You will find below the list of publications of all the members of the Peptides, Glycoconjugates and Metals in Biology research pole. For individual or theme-specific publications, please consult the research or the personal pages via the members list using the sidebar navigation tool.
2016 |
Isomerization and Oligomerization of Truncated and Mutated Tau Forms by FKBP52 are Independent Processes Article de journal A Kamah; F X Cantrelle; I Huvent; J Giustiniani; K Guillemeau; C Byrne; Y Jacquot; I Landrieu; E E Baulieu; C Smet; B Chambraud; G Lippens Journal of Molecular Biology, 428 (6), p. 1080–1090, 2016. @article{Kamah:2016, title = {Isomerization and Oligomerization of Truncated and Mutated Tau Forms by FKBP52 are Independent Processes}, author = {A Kamah and F X Cantrelle and I Huvent and J Giustiniani and K Guillemeau and C Byrne and Y Jacquot and I Landrieu and E E Baulieu and C Smet and B Chambraud and G Lippens}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84959261786&doi=10.1016%2fj.jmb.2016.02.015&partnerID=40&md5=fa8b175818d6093a38424aca150b0eb2}, doi = {10.1016/j.jmb.2016.02.015}, year = {2016}, date = {2016-01-01}, journal = {Journal of Molecular Biology}, volume = {428}, number = {6}, pages = {1080--1090}, abstract = {The aggregation of the neuronal Tau protein is one molecular hallmark of Alzheimer's disease and other related tauopathies, but the precise molecular mechanisms of the aggregation process remain unclear. The FK506 binding protein FKBP52 is able to induce oligomers in the pathogenic Tau P301L mutant and in a truncated form of the wild-type human Tau protein. Here, we investigate whether FKBP52's capacity to induce Tau oligomers depends on its prolyl cis/trans isomerase activity. We find that FKBP52 indeed can isomerize selected prolyl bonds in the different Tau proteins, and that this activity is carried solely by its first FK506 binding domain. Its capacity to oligomerize Tau is, however, not linked to this peptidyl-prolyl isomerase activity. In addition, we identified a novel molecular interaction implying the PHF6 peptide of Tau and the FK1/FK2 domains of FKBP52 independent of FK506 binding; these data point toward a non-catalytic molecular interaction that might govern the effect of FKBP52 on Tau. © 2016 Elsevier Ltd. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The aggregation of the neuronal Tau protein is one molecular hallmark of Alzheimer's disease and other related tauopathies, but the precise molecular mechanisms of the aggregation process remain unclear. The FK506 binding protein FKBP52 is able to induce oligomers in the pathogenic Tau P301L mutant and in a truncated form of the wild-type human Tau protein. Here, we investigate whether FKBP52's capacity to induce Tau oligomers depends on its prolyl cis/trans isomerase activity. We find that FKBP52 indeed can isomerize selected prolyl bonds in the different Tau proteins, and that this activity is carried solely by its first FK506 binding domain. Its capacity to oligomerize Tau is, however, not linked to this peptidyl-prolyl isomerase activity. In addition, we identified a novel molecular interaction implying the PHF6 peptide of Tau and the FK1/FK2 domains of FKBP52 independent of FK506 binding; these data point toward a non-catalytic molecular interaction that might govern the effect of FKBP52 on Tau. © 2016 Elsevier Ltd. All rights reserved. |
A β-turn motif in the steroid hormone receptor's ligand-binding domains interacts with the peptidyl-prolyl isomerase (PPIase) catalytic site of the immunophilin FKBP52 Article de journal C Byrne; M A Henen; M Belnou; F -X Cantrelle; A Kamah; H Qi; J Giustiniani; B Chambraud; E -E Baulieu; G Lippens; I Landrieu; Y Jacquot Biochemistry, 55 (38), p. 5366–5376, 2016. @article{Byrne:2016, title = {A β-turn motif in the steroid hormone receptor's ligand-binding domains interacts with the peptidyl-prolyl isomerase (PPIase) catalytic site of the immunophilin FKBP52}, author = {C Byrne and M A Henen and M Belnou and F -X Cantrelle and A Kamah and H Qi and J Giustiniani and B Chambraud and E -E Baulieu and G Lippens and I Landrieu and Y Jacquot}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84989260723&doi=10.1021%2facs.biochem.6b00506&partnerID=40&md5=d6d3646263e00c9bd3049c235c894a13}, doi = {10.1021/acs.biochem.6b00506}, year = {2016}, date = {2016-01-01}, journal = {Biochemistry}, volume = {55}, number = {38}, pages = {5366--5376}, abstract = {The immunophilin FKBP52 interacts with nuclear steroid hormone receptors. Studying the crystal structure of human estrogen receptor α (hERα) and using nuclear magnetic resonance, we show here that the short V364PGF367 sequence, which is located within its ligand-binding domain and adopts a type II β-turn conformation in the protein, binds the peptidyl-prolyl isomerase (PPIase or rotamase) FK1 domain of FKBP52. Interestingly, this turn motif displays strong similarities with the FKBP52 FK1 domain-binding moiety of macrolide immunomodulators such as rapamycin and GPI-1046, an immunophilin ligand with neuroprotective characteristics. An increase in the hydrophobicity of the residue preceding the proline and cyclization of the VPGF peptide strengthen its recognition by the FK1 domain of FKBP52. Replacement of the Pro residue with a dimethylproline also enhances this interaction. Our study not only contributes to a better understanding of how the interaction between the FK1 domain of FKBP52 and steroid hormone receptors most likely works but also opens new avenues for the synthesis of FKBP52 FK1 peptide ligands appropriate for the control of hormone-dependent physiological mechanisms or of the functioning of the Tau protein. Indeed, it has been shown that FKBP52 is involved in the intraneuronal dynamics of the Tau protein. © 2016 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The immunophilin FKBP52 interacts with nuclear steroid hormone receptors. Studying the crystal structure of human estrogen receptor α (hERα) and using nuclear magnetic resonance, we show here that the short V364PGF367 sequence, which is located within its ligand-binding domain and adopts a type II β-turn conformation in the protein, binds the peptidyl-prolyl isomerase (PPIase or rotamase) FK1 domain of FKBP52. Interestingly, this turn motif displays strong similarities with the FKBP52 FK1 domain-binding moiety of macrolide immunomodulators such as rapamycin and GPI-1046, an immunophilin ligand with neuroprotective characteristics. An increase in the hydrophobicity of the residue preceding the proline and cyclization of the VPGF peptide strengthen its recognition by the FK1 domain of FKBP52. Replacement of the Pro residue with a dimethylproline also enhances this interaction. Our study not only contributes to a better understanding of how the interaction between the FK1 domain of FKBP52 and steroid hormone receptors most likely works but also opens new avenues for the synthesis of FKBP52 FK1 peptide ligands appropriate for the control of hormone-dependent physiological mechanisms or of the functioning of the Tau protein. Indeed, it has been shown that FKBP52 is involved in the intraneuronal dynamics of the Tau protein. © 2016 American Chemical Society. |
The Use of Mn(II) Bound to His-tags as Genetically Encodable Spin-Label for Nanometric Distance Determination in Proteins Article de journal H Y V Ching; F C Mascali; H C Bertrand; E M Bruch; P Demay-Drouhard; R M Rasia; C Policar; L C Tabares; S Un Journal of Physical Chemistry Letters, 7 (6), p. 1072–1076, 2016. @article{Ching:2016, title = {The Use of Mn(II) Bound to His-tags as Genetically Encodable Spin-Label for Nanometric Distance Determination in Proteins}, author = {H Y V Ching and F C Mascali and H C Bertrand and E M Bruch and P Demay-Drouhard and R M Rasia and C Policar and L C Tabares and S Un}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84962539336&doi=10.1021%2facs.jpclett.6b00362&partnerID=40&md5=16161dac85830ffcae821a41e6480d4c}, doi = {10.1021/acs.jpclett.6b00362}, year = {2016}, date = {2016-01-01}, journal = {Journal of Physical Chemistry Letters}, volume = {7}, number = {6}, pages = {1072--1076}, abstract = {A genetically encodable paramagnetic spin-label capable of self-assembly from naturally available components would offer a means for studying the in-cell structure and interactions of a protein by electron paramagnetic resonance (EPR). Here, we demonstrate pulse electron-electron double resonance (DEER) measurements on spin-labels consisting of Mn(II) ions coordinated to a sequence of histidines, so-called His-tags, that are ubiquitously added by genetic engineering to facilitate protein purification. Although the affinity of His-tags for Mn(II) was low (800 μM), Mn(II)-bound His-tags yielded readily detectable DEER time traces even at concentrations expected in cells. We were able to determine accurately the distance between two His-tag Mn(II) spin-labels at the ends of a rigid helical polyproline peptide of known structure, as well as at the ends of a completely cell-synthesized 3-helix bundle. This approach not only greatly simplifies the labeling procedure but also represents a first step towards using self-assembling metal spin-labels for in-cell distance measurements. © 2016 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A genetically encodable paramagnetic spin-label capable of self-assembly from naturally available components would offer a means for studying the in-cell structure and interactions of a protein by electron paramagnetic resonance (EPR). Here, we demonstrate pulse electron-electron double resonance (DEER) measurements on spin-labels consisting of Mn(II) ions coordinated to a sequence of histidines, so-called His-tags, that are ubiquitously added by genetic engineering to facilitate protein purification. Although the affinity of His-tags for Mn(II) was low (800 μM), Mn(II)-bound His-tags yielded readily detectable DEER time traces even at concentrations expected in cells. We were able to determine accurately the distance between two His-tag Mn(II) spin-labels at the ends of a rigid helical polyproline peptide of known structure, as well as at the ends of a completely cell-synthesized 3-helix bundle. This approach not only greatly simplifies the labeling procedure but also represents a first step towards using self-assembling metal spin-labels for in-cell distance measurements. © 2016 American Chemical Society. |
RIDME spectroscopy on high-spin Mn2+ centers Article de journal D Akhmetzyanov; H Y V Ching; V Denysenkov; P Demay-Drouhard; H C Bertrand; L C Tabares; C Policar; T F Prisner; S Un Physical Chemistry Chemical Physics, 18 (44), p. 30857–30866, 2016. @article{Akhmetzyanov:2016, title = {RIDME spectroscopy on high-spin Mn2+ centers}, author = {D Akhmetzyanov and H Y V Ching and V Denysenkov and P Demay-Drouhard and H C Bertrand and L C Tabares and C Policar and T F Prisner and S Un}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85025823502&doi=10.1039%2fc6cp05239h&partnerID=40&md5=d3a6cd609c88b382cf0297ed361d4003}, doi = {10.1039/c6cp05239h}, year = {2016}, date = {2016-01-01}, journal = {Physical Chemistry Chemical Physics}, volume = {18}, number = {44}, pages = {30857--30866}, abstract = {Pulsed EPR dipolar spectroscopy is a powerful tool for determining the structure and conformational dynamics of biological macromolecules, as it allows precise measurements of distances in the range of 1.5-10 nm. Utilization of high-spin Mn2+ species as spin probes for distance measurements is of significant interest, because they are biologically compatible and endogenous in numerous biological systems. However, to date dipolar spectroscopy experiments with this kind of species have been underexplored. Here we present pulsed electron electron double resonance (PELDOR also called DEER) and relaxation-induced dipolar modulation enhancement (RIDME) experiments, which have been performed at W-band (94 GHz) and J-band frequencies (263 GHz) on a bis-MnDOTA (DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate) model system. The distances obtained from these experiments are in good agreement with predictions. RIDME experiments reveal a significantly higher modulation depth compared to PELDOR, which is an important consideration for biological samples. These experiments also feature higher harmonics of the dipolar coupling frequency due to effective multiple-quantum relaxation of high-spin Mn2+ as well as the multiple-component background function. Harmonics of the dipolar coupling frequency were taken into account by including additional terms in the kernel function of Tikhonov regularization analysis. © The Owner Societies 2016.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Pulsed EPR dipolar spectroscopy is a powerful tool for determining the structure and conformational dynamics of biological macromolecules, as it allows precise measurements of distances in the range of 1.5-10 nm. Utilization of high-spin Mn2+ species as spin probes for distance measurements is of significant interest, because they are biologically compatible and endogenous in numerous biological systems. However, to date dipolar spectroscopy experiments with this kind of species have been underexplored. Here we present pulsed electron electron double resonance (PELDOR also called DEER) and relaxation-induced dipolar modulation enhancement (RIDME) experiments, which have been performed at W-band (94 GHz) and J-band frequencies (263 GHz) on a bis-MnDOTA (DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate) model system. The distances obtained from these experiments are in good agreement with predictions. RIDME experiments reveal a significantly higher modulation depth compared to PELDOR, which is an important consideration for biological samples. These experiments also feature higher harmonics of the dipolar coupling frequency due to effective multiple-quantum relaxation of high-spin Mn2+ as well as the multiple-component background function. Harmonics of the dipolar coupling frequency were taken into account by including additional terms in the kernel function of Tikhonov regularization analysis. © The Owner Societies 2016. |
Photophysical properties of single core multimodal probe for imaging (SCoMPI) in a membrane model and in cells Article de journal S Hostachy; J -M Swiecicki; C Sandt; N Delsuc; C Policar Dalton Transactions, 45 (7), p. 2791–2795, 2016. @article{Hostachy:2016, title = {Photophysical properties of single core multimodal probe for imaging (SCoMPI) in a membrane model and in cells}, author = {S Hostachy and J -M Swiecicki and C Sandt and N Delsuc and C Policar}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84958064177&doi=10.1039%2fc5dt03819g&partnerID=40&md5=fb027086e6424b54b23cc2c11098e273}, doi = {10.1039/c5dt03819g}, year = {2016}, date = {2016-01-01}, journal = {Dalton Transactions}, volume = {45}, number = {7}, pages = {2791--2795}, abstract = {The spectroscopic properties of two luminescent Re(i) tricarbonyl complexes conjugated with two cell-penetrating peptides were examined. Fluorescence experiments and IR quantification in membrane models and in cells showed unexpectedly strong luminescence enhancement for one of the complexes in a lipid environment. © The Royal Society of Chemistry 2016.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The spectroscopic properties of two luminescent Re(i) tricarbonyl complexes conjugated with two cell-penetrating peptides were examined. Fluorescence experiments and IR quantification in membrane models and in cells showed unexpectedly strong luminescence enhancement for one of the complexes in a lipid environment. © The Royal Society of Chemistry 2016. |
New insight into the structural, electrochemical and biological aspects of macroacyclic Cu(II) complexes derived from S-substituted dithiocarbazate schiff bases Article de journal M L Low; L Maigre; M I M Tahir; E R T Tiekink; P Dorlet; R Guillot; T B Ravoof; R Rosli; J -M Pagès; C Policar; N Delsuc; K A Crouse European Journal of Medicinal Chemistry, 120 , p. 1–12, 2016. @article{Low:2016, title = {New insight into the structural, electrochemical and biological aspects of macroacyclic Cu(II) complexes derived from S-substituted dithiocarbazate schiff bases}, author = {M L Low and L Maigre and M I M Tahir and E R T Tiekink and P Dorlet and R Guillot and T B Ravoof and R Rosli and J -M Pag\`{e}s and C Policar and N Delsuc and K A Crouse}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84967102584&doi=10.1016%2fj.ejmech.2016.04.027&partnerID=40&md5=71cde180942655ac9c57205e82887fcf}, doi = {10.1016/j.ejmech.2016.04.027}, year = {2016}, date = {2016-01-01}, journal = {European Journal of Medicinal Chemistry}, volume = {120}, pages = {1--12}, abstract = {Copper (II) complexes synthesized from the products of condensation of S-methyl- and S-benzyldithiocarbazate with 2,5-hexanedione (SMHDH2 and SBHDH2 respectively) have been characterized using various physicochemical (elemental analysis, molar conductivity, magnetic susceptibility) and spectroscopic (infrared, electronic) methods. The structures of SMHDH2, its copper (II) complex, CuSMHD, and the related CuSBHD complex as well as a pyrrole byproduct, SBPY, have been determined by single crystal X-ray diffraction. In order to provide more insight into the behaviour of the complexes in solution, electron paramagnetic resonance (EPR) and electrochemical experiments were performed. Antibacterial activity and cytotoxicity were evaluated. The compounds, dissolved in 0.5% and 5% DMSO, showed a wide range of antibacterial activity against 10 strains of Gram-positive and Gram-negative bacteria. Investigations of the effects of efflux pumps and membrane penetration on antibacterial activity are reported herein. Antiproliferation activity was observed to be enhanced by complexation with copper. Preliminary screening showed Cu complexes are strongly active against human breast adenocarcinoma cancer cell lines MDA-MB-231 and MCF-7. © 2016 Published by Elsevier Masson SAS.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Copper (II) complexes synthesized from the products of condensation of S-methyl- and S-benzyldithiocarbazate with 2,5-hexanedione (SMHDH2 and SBHDH2 respectively) have been characterized using various physicochemical (elemental analysis, molar conductivity, magnetic susceptibility) and spectroscopic (infrared, electronic) methods. The structures of SMHDH2, its copper (II) complex, CuSMHD, and the related CuSBHD complex as well as a pyrrole byproduct, SBPY, have been determined by single crystal X-ray diffraction. In order to provide more insight into the behaviour of the complexes in solution, electron paramagnetic resonance (EPR) and electrochemical experiments were performed. Antibacterial activity and cytotoxicity were evaluated. The compounds, dissolved in 0.5% and 5% DMSO, showed a wide range of antibacterial activity against 10 strains of Gram-positive and Gram-negative bacteria. Investigations of the effects of efflux pumps and membrane penetration on antibacterial activity are reported herein. Antiproliferation activity was observed to be enhanced by complexation with copper. Preliminary screening showed Cu complexes are strongly active against human breast adenocarcinoma cancer cell lines MDA-MB-231 and MCF-7. © 2016 Published by Elsevier Masson SAS. |
Monitoring bicosomes containing antioxidants in normal and irradiated skin Article de journal E Fernández; S Hostachy; C Sandt; G Rodríguez; H C Bertrand; S Clède; M Cócera; A D L Maza; F Lambert; C Policar; O López RSC Advances, 6 (76), p. 72559–72567, 2016. @article{Fernandez:2016, title = {Monitoring bicosomes containing antioxidants in normal and irradiated skin}, author = {E Fern\'{a}ndez and S Hostachy and C Sandt and G Rodr\'{i}guez and H C Bertrand and S Cl\`{e}de and M C\'{o}cera and A D L Maza and F Lambert and C Policar and O L\'{o}pez}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84982684419&doi=10.1039%2fc6ra11170j&partnerID=40&md5=126bef944046a09450ae86ce5985c07f}, doi = {10.1039/c6ra11170j}, year = {2016}, date = {2016-01-01}, journal = {RSC Advances}, volume = {6}, number = {76}, pages = {72559--72567}, abstract = {This study evaluates the penetration of bicosome systems incorporating two different antioxidants into normal skin and skin exposed to ultraviolet-visible radiation (UV-VIS) by Fourier-transform infrared microspectroscopy (FT-IR) using synchrotron radiation. Bicosomes are phospholipid assemblies based on mixtures of discoidal lipid structures protected by spherical lipid vesicles able to incorporate different molecules. In the current work, the antioxidants incorporated in these systems were β-carotene and a Mn complex as a superoxide dismutase (SOD) mimic. Additionally, a rhenium tri-carbonyl derivative was incorporated in the bicosome systems in order to map their penetration following the tag specific carbonyl signal by FT-IR microspectroscopy. The characterization of bicosome systems using the dynamic light scattering technique (DLS) showed a modification in the size of the systems containing β-carotene (Bcβ) or MnII complex (BcMn). After skin permeation, FT-IR results indicated a higher and deeper penetration of the BcMn system than the Bcβ system into the skin. Likely, the different physicochemical properties of both antioxidants could be responsible for this effect. Moreover, the penetration of both bicosome systems in irradiated skin was lower in comparison with the normal skin. This fact could be a consequence of the alteration of water transport in the skin during the irradiation process. In conclusion, these results indicated the effectiveness of bicosome systems as skin carriers, and provide information to protect skin under radiation using antioxidants. © The Royal Society of Chemistry 2016.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This study evaluates the penetration of bicosome systems incorporating two different antioxidants into normal skin and skin exposed to ultraviolet-visible radiation (UV-VIS) by Fourier-transform infrared microspectroscopy (FT-IR) using synchrotron radiation. Bicosomes are phospholipid assemblies based on mixtures of discoidal lipid structures protected by spherical lipid vesicles able to incorporate different molecules. In the current work, the antioxidants incorporated in these systems were β-carotene and a Mn complex as a superoxide dismutase (SOD) mimic. Additionally, a rhenium tri-carbonyl derivative was incorporated in the bicosome systems in order to map their penetration following the tag specific carbonyl signal by FT-IR microspectroscopy. The characterization of bicosome systems using the dynamic light scattering technique (DLS) showed a modification in the size of the systems containing β-carotene (Bcβ) or MnII complex (BcMn). After skin permeation, FT-IR results indicated a higher and deeper penetration of the BcMn system than the Bcβ system into the skin. Likely, the different physicochemical properties of both antioxidants could be responsible for this effect. Moreover, the penetration of both bicosome systems in irradiated skin was lower in comparison with the normal skin. This fact could be a consequence of the alteration of water transport in the skin during the irradiation process. In conclusion, these results indicated the effectiveness of bicosome systems as skin carriers, and provide information to protect skin under radiation using antioxidants. © The Royal Society of Chemistry 2016. |
Human TTR conformation altered by rhenium tris-carbonyl derivatives Article de journal L Ciccone; C Policar; E A Stura; W Shepard Journal of Structural Biology, 195 (3), p. 353–364, 2016. @article{Ciccone:2016, title = {Human TTR conformation altered by rhenium tris-carbonyl derivatives}, author = {L Ciccone and C Policar and E A Stura and W Shepard}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84991363542&doi=10.1016%2fj.jsb.2016.07.002&partnerID=40&md5=86e7e8d956bfdb39ae832e52b01a9dea}, doi = {10.1016/j.jsb.2016.07.002}, year = {2016}, date = {2016-01-01}, journal = {Journal of Structural Biology}, volume = {195}, number = {3}, pages = {353--364}, abstract = {Transthyretin (TTR) is a 54 kDa homotetrameric serum protein that transports thyroxine (T4) and retinol. TTR is potentially amyloidogenic due to homotetramer dissociation into monomeric intermediates that self-assemble as amyloid deposits and insoluble fibrils. Most crystallographic structures, including those of amyloidogenic variants show the same tetramer without major variations in the monomer-monomer interface nor in the volume of the interdimeric cavity. Soaking TTR crystals in a solution containing rhenium tris-carbonyl derivatives yields a TTR conformer never observed before. Only one of the two monomers of the crystallographic dimer is significantly altered, and the inner part of the T4 binding cavity is expanded at one end and shrunk at the other. The result redefines the mechanism of allosteric communication between the two sites, suggesting that negative cooperativity is a function of dimer asymmetry, which can be induced through internal or external binding. An aspect that remains unexplained is why the conformational changes are ubiquitous throughout the crystal although the heavy metal content of the derivatized crystals is relatively low. The conformational changes observed, which include Leu82, may represent a form of TTR better at scavenging β-Amyloid. At a resolution of 1.69 r{A}, with excellent refinement statistics and well defined electron density for all parts of the structure, it is possible to envisage answering important questions that range from protein cooperative behavior to heavy atom induced protein conformational modifications that can result in crystallographic non-isomorphism. © 2016 Elsevier Inc.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Transthyretin (TTR) is a 54 kDa homotetrameric serum protein that transports thyroxine (T4) and retinol. TTR is potentially amyloidogenic due to homotetramer dissociation into monomeric intermediates that self-assemble as amyloid deposits and insoluble fibrils. Most crystallographic structures, including those of amyloidogenic variants show the same tetramer without major variations in the monomer-monomer interface nor in the volume of the interdimeric cavity. Soaking TTR crystals in a solution containing rhenium tris-carbonyl derivatives yields a TTR conformer never observed before. Only one of the two monomers of the crystallographic dimer is significantly altered, and the inner part of the T4 binding cavity is expanded at one end and shrunk at the other. The result redefines the mechanism of allosteric communication between the two sites, suggesting that negative cooperativity is a function of dimer asymmetry, which can be induced through internal or external binding. An aspect that remains unexplained is why the conformational changes are ubiquitous throughout the crystal although the heavy metal content of the derivatized crystals is relatively low. The conformational changes observed, which include Leu82, may represent a form of TTR better at scavenging β-Amyloid. At a resolution of 1.69 Å, with excellent refinement statistics and well defined electron density for all parts of the structure, it is possible to envisage answering important questions that range from protein cooperative behavior to heavy atom induced protein conformational modifications that can result in crystallographic non-isomorphism. © 2016 Elsevier Inc. |
Bioinspired superoxide-dismutase mimics: The effects of functionalization with cationic polyarginine peptides Article de journal H Y V Ching; I Kenkel; N Delsuc; E Mathieu; I Ivanović-Burmazović; C Policar Journal of Inorganic Biochemistry, 160 , p. 172–179, 2016. @article{Ching:2016a, title = {Bioinspired superoxide-dismutase mimics: The effects of functionalization with cationic polyarginine peptides}, author = {H Y V Ching and I Kenkel and N Delsuc and E Mathieu and I Ivanovi\'{c}-Burmazovi\'{c} and C Policar}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84964372716&doi=10.1016%2fj.jinorgbio.2016.01.025&partnerID=40&md5=035d0c2b5ffd4ee0b6fb74df285838da}, doi = {10.1016/j.jinorgbio.2016.01.025}, year = {2016}, date = {2016-01-01}, journal = {Journal of Inorganic Biochemistry}, volume = {160}, pages = {172--179}, abstract = {Continuing a bio-mimetic approach, we have prepared peptide conjugates of a superoxide dismutase (SOD) mimic [MnL]+ (where HL = N-(2-hydroxybenzyl)-N,N'-bis[2-(N-methylimidazolyl)methyl]ethane-1,2-diamine), namely [MnL'-Arg(n-1)]n+ (where n = 2, 4, 7 and 10) and [MnL'-Gly1]+. [MnL'-Arg(n-1)]n+ contained cationic residue(s) that emulate the electrostatic channel of the enzyme. Physicochemical methods showed that functionalization at the secondary amine of HL did not impair coordination to MnII with association constants (Kassoc) between 1.6 and 3.3 × 106 M- 1. The MnIII/MnII redox potential of the conjugates was between 0.27 and 0.30 V vs SCE, slightly higher than [MnL]+ under the same conditions, but remain at a value that facilitates O2•- dismutation. The catalytic rate constant (kcat) of the dismutation for the series was studied using a direct stopped-flow method, which showed that for compounds with the same overall charge, the alkylation of the secondary amine of [MnL]+ (kcat = 5.0 ± 0.1 × 106 M- 1 s- 1) led to a lower value (i.e. for [MnL'Gly]+}, keywords = {}, pubstate = {published}, tppubtype = {article} } Continuing a bio-mimetic approach, we have prepared peptide conjugates of a superoxide dismutase (SOD) mimic [MnL]+ (where HL = N-(2-hydroxybenzyl)-N,N'-bis[2-(N-methylimidazolyl)methyl]ethane-1,2-diamine), namely [MnL'-Arg(n-1)]n+ (where n = 2, 4, 7 and 10) and [MnL'-Gly1]+. [MnL'-Arg(n-1)]n+ contained cationic residue(s) that emulate the electrostatic channel of the enzyme. Physicochemical methods showed that functionalization at the secondary amine of HL did not impair coordination to MnII with association constants (Kassoc) between 1.6 and 3.3 × 106 M- 1. The MnIII/MnII redox potential of the conjugates was between 0.27 and 0.30 V vs SCE, slightly higher than [MnL]+ under the same conditions, but remain at a value that facilitates O2•- dismutation. The catalytic rate constant (kcat) of the dismutation for the series was studied using a direct stopped-flow method, which showed that for compounds with the same overall charge, the alkylation of the secondary amine of [MnL]+ (kcat = 5.0 ± 0.1 × 106 M- 1 s- 1) led to a lower value (i.e. for [MnL'Gly]+ |
Bimodal X-ray and Infrared Imaging of an Organometallic Derivative of Praziquantel in Schistosoma mansoni Article de journal S Clède; N Cowan; F Lambert; H C Bertrand; R Rubbiani; M Patra; J Hess; C Sandt; N Trcera; G Gasser; J Keiser; C Policar ChemBioChem, 17 (11), p. 1004–1007, 2016. @article{Clede:2016, title = {Bimodal X-ray and Infrared Imaging of an Organometallic Derivative of Praziquantel in Schistosoma mansoni}, author = {S Cl\`{e}de and N Cowan and F Lambert and H C Bertrand and R Rubbiani and M Patra and J Hess and C Sandt and N Trcera and G Gasser and J Keiser and C Policar}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84973124415&doi=10.1002%2fcbic.201500688&partnerID=40&md5=608b1bb28a5237e0717a29ee815e73bc}, doi = {10.1002/cbic.201500688}, year = {2016}, date = {2016-01-01}, journal = {ChemBioChem}, volume = {17}, number = {11}, pages = {1004--1007}, abstract = {An organometallic derivative of praziquantel was studied directly in worms by using inductively coupled plasma-mass spectrometry (ICP-MS) for quantification and synchrotron-based imaging. X-ray fluorescence (XRF) and IR absorption spectromicroscopy were used for the first time in combination to directly locate this organometallic drug candidate in schistosomes. The detection of both CO (IR) and Cr (XRF) signatures proved that the Cr(CO)3 core remained intact in the worms. Images showed a preferential accumulation at the worm's tegument, consistent with a possible targeting of the calcium channel but not excluding other biological targets inside the worm. Imaginative imaging: Two synchrotron-based techniques - X-ray fluorescence and IR absorption spectroscopy - were used in combination for the first time to directly locate an organometallic drug candidate in schistosomes. This represents a novel approach to examine mechanisms of actions for organometallic compounds and might lead to the discovery of new drug candidates. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.}, keywords = {}, pubstate = {published}, tppubtype = {article} } An organometallic derivative of praziquantel was studied directly in worms by using inductively coupled plasma-mass spectrometry (ICP-MS) for quantification and synchrotron-based imaging. X-ray fluorescence (XRF) and IR absorption spectromicroscopy were used for the first time in combination to directly locate this organometallic drug candidate in schistosomes. The detection of both CO (IR) and Cr (XRF) signatures proved that the Cr(CO)3 core remained intact in the worms. Images showed a preferential accumulation at the worm's tegument, consistent with a possible targeting of the calcium channel but not excluding other biological targets inside the worm. Imaginative imaging: Two synchrotron-based techniques - X-ray fluorescence and IR absorption spectroscopy - were used in combination for the first time to directly locate an organometallic drug candidate in schistosomes. This represents a novel approach to examine mechanisms of actions for organometallic compounds and might lead to the discovery of new drug candidates. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. |
A Bis-Manganese(II)–DOTA Complex for Pulsed Dipolar Spectroscopy Article de journal P Demay-Drouhard; H Y V Ching; D Akhmetzyanov; R Guillot; L C Tabares; H C Bertrand; C Policar ChemPhysChem, p. 2066–2078, 2016. @article{Demay-Drouhard:2016, title = {A Bis-Manganese(II)\textendashDOTA Complex for Pulsed Dipolar Spectroscopy}, author = {P Demay-Drouhard and H Y V Ching and D Akhmetzyanov and R Guillot and L C Tabares and H C Bertrand and C Policar}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84977597209&doi=10.1002%2fcphc.201600234&partnerID=40&md5=38a2466ad0f00d0edb158d200429986c}, doi = {10.1002/cphc.201600234}, year = {2016}, date = {2016-01-01}, journal = {ChemPhysChem}, pages = {2066--2078}, abstract = {High-spin gadolinium(III) and manganese(II) complexes have emerged as alternatives to standard nitroxide radical spin labels for measuring nanometric distances by using pulsed electron\textendashelectron double resonance (PELDOR or DEER) at high fields/frequencies. For certain complexes, particularly those with relatively small zero-field splitting (ZFS) and short distances between the two metal centers, the pseudosecular term of the dipolar coupling Hamiltonian is non-negligible. However, in general, the contribution from this term during conventional data analysis is masked by the flexibility of the molecule of interest and/or the long tethers connecting them to the spin labels. The efficient synthesis of a model system consisting of two [Mn(dota)]2− (MnDOTA; DOTA4−=1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate) directly connected to the ends of a central rodlike oligo(phenylene\textendashethynylene) (OPE) spacer is reported. The rigidity of the OPE is confirmed by Q-band PELDOR measurements on a bis-nitroxide analogue. The MnII−MnII distance distribution profile determined by W-band PELDOR is in reasonable agreement with one simulated by using a simple rotamer analysis. The small degree of flexibility arising from the linking MnDOTA arm appears to outweigh the contribution from the pseudosecular term at this interspin distance. This study illustrates the potential of MnDOTA-based spin labels for measuring fairly short nanometer distances, and also presents an interesting candidate for in-depth studies of pulsed dipolar spectroscopy methods on MnII−MnII systems. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim}, keywords = {}, pubstate = {published}, tppubtype = {article} } High-spin gadolinium(III) and manganese(II) complexes have emerged as alternatives to standard nitroxide radical spin labels for measuring nanometric distances by using pulsed electron–electron double resonance (PELDOR or DEER) at high fields/frequencies. For certain complexes, particularly those with relatively small zero-field splitting (ZFS) and short distances between the two metal centers, the pseudosecular term of the dipolar coupling Hamiltonian is non-negligible. However, in general, the contribution from this term during conventional data analysis is masked by the flexibility of the molecule of interest and/or the long tethers connecting them to the spin labels. The efficient synthesis of a model system consisting of two [Mn(dota)]2− (MnDOTA; DOTA4−=1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate) directly connected to the ends of a central rodlike oligo(phenylene–ethynylene) (OPE) spacer is reported. The rigidity of the OPE is confirmed by Q-band PELDOR measurements on a bis-nitroxide analogue. The MnII−MnII distance distribution profile determined by W-band PELDOR is in reasonable agreement with one simulated by using a simple rotamer analysis. The small degree of flexibility arising from the linking MnDOTA arm appears to outweigh the contribution from the pseudosecular term at this interspin distance. This study illustrates the potential of MnDOTA-based spin labels for measuring fairly short nanometer distances, and also presents an interesting candidate for in-depth studies of pulsed dipolar spectroscopy methods on MnII−MnII systems. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim |
Indolin-2-one compounds targeting thioredoxin reductase as potential anticancer drug leads Article de journal K K Kaminska; H C Bertrand; H Tajima; W C Stafford; Q Cheng; W Chen; G Wells; E S J Arner; E -H Chew Oncotarget, 7 (26), p. 40233–40251, 2016. @article{Kaminska:2016, title = {Indolin-2-one compounds targeting thioredoxin reductase as potential anticancer drug leads}, author = {K K Kaminska and H C Bertrand and H Tajima and W C Stafford and Q Cheng and W Chen and G Wells and E S J Arner and E -H Chew}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84983002228&doi=10.18632%2foncotarget.9579&partnerID=40&md5=21b5120cc53147d2dce47cf9545ab207}, doi = {10.18632/oncotarget.9579}, year = {2016}, date = {2016-01-01}, journal = {Oncotarget}, volume = {7}, number = {26}, pages = {40233--40251}, abstract = {Several compounds bearing the indolinone chemical scaffold are known to possess anticancer properties. For example, the tyrosine kinase inhibitor sunitinib is an arylideneindolin-2-one compound. The chemical versatility associated with structural modifications of indolinone compounds underlies the potential to discover additional derivatives possessing anticancer properties. Previously synthesized 3-(2-oxoethylidene)indolin-2-one compounds, also known as supercinnamaldehyde (SCA) compounds in reference to the parent compound 1 [1-methyl-3(2- oxopropylidene)indolin-2-one], bear a nitrogen-linked α,β-unsaturated carbonyl (Michael acceptor) moiety. Here we found that analogs bearing N-substituents, in particular compound 4 and 5 carrying an N-butyl and N-benzyl substituent, respectively, were strongly cytotoxic towards human HCT 116 colorectal and MCF-7 breast carcinoma cells. These compounds also displayed strong thioredoxin reductase (TrxR) inhibitory activity that was likely attributed to the electrophilicity of the Michael acceptor moiety. Their selectivity towards cellular TrxR inhibition over related antioxidant enzymes glutathione reductase (GR), thioredoxin (Trx) and glutathione peroxidase (GPx) was mediated through targeting of the selenocysteine (Sec) residue in the highly accessible C-terminal active site of TrxR. TrxR inhibition mediated by indolin-2-one compounds led to cellular Trx oxidation, increased oxidative stress and activation of apoptosis signal-regulating kinase 1 (ASK1). These events also led to activation of p38 and JNK mitogen-activated protein kinase (MAPK) signaling pathways, and cell death with apoptotic features of PARP cleavage and caspase 3 activation. In conclusion, these results suggest that indolin-2-one-based compounds specifically targeting TrxR may serve as novel drug leads for anticancer therapy.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Several compounds bearing the indolinone chemical scaffold are known to possess anticancer properties. For example, the tyrosine kinase inhibitor sunitinib is an arylideneindolin-2-one compound. The chemical versatility associated with structural modifications of indolinone compounds underlies the potential to discover additional derivatives possessing anticancer properties. Previously synthesized 3-(2-oxoethylidene)indolin-2-one compounds, also known as supercinnamaldehyde (SCA) compounds in reference to the parent compound 1 [1-methyl-3(2- oxopropylidene)indolin-2-one], bear a nitrogen-linked α,β-unsaturated carbonyl (Michael acceptor) moiety. Here we found that analogs bearing N-substituents, in particular compound 4 and 5 carrying an N-butyl and N-benzyl substituent, respectively, were strongly cytotoxic towards human HCT 116 colorectal and MCF-7 breast carcinoma cells. These compounds also displayed strong thioredoxin reductase (TrxR) inhibitory activity that was likely attributed to the electrophilicity of the Michael acceptor moiety. Their selectivity towards cellular TrxR inhibition over related antioxidant enzymes glutathione reductase (GR), thioredoxin (Trx) and glutathione peroxidase (GPx) was mediated through targeting of the selenocysteine (Sec) residue in the highly accessible C-terminal active site of TrxR. TrxR inhibition mediated by indolin-2-one compounds led to cellular Trx oxidation, increased oxidative stress and activation of apoptosis signal-regulating kinase 1 (ASK1). These events also led to activation of p38 and JNK mitogen-activated protein kinase (MAPK) signaling pathways, and cell death with apoptotic features of PARP cleavage and caspase 3 activation. In conclusion, these results suggest that indolin-2-one-based compounds specifically targeting TrxR may serve as novel drug leads for anticancer therapy. |
Hexagonal-shaped chondroitin sulfate self-assemblies have exalted anti-HSV-2 activity Article de journal A Galus; J -M Mallet; D Lembo; V Cagno; M Djabourov; H Lortat-Jacob; K Bouchemal Carbohydrate Polymers, 136 , p. 113–120, 2016. @article{Galus:2016, title = {Hexagonal-shaped chondroitin sulfate self-assemblies have exalted anti-HSV-2 activity}, author = {A Galus and J -M Mallet and D Lembo and V Cagno and M Djabourov and H Lortat-Jacob and K Bouchemal}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84941910307&doi=10.1016%2fj.carbpol.2015.08.054&partnerID=40&md5=cea3ce4315cf160b6b8b3c19d4ab3c9a}, doi = {10.1016/j.carbpol.2015.08.054}, year = {2016}, date = {2016-01-01}, journal = {Carbohydrate Polymers}, volume = {136}, pages = {113--120}, abstract = {The initial step in mucosal infection by the herpes simplex virus type 2 (HSV-2) requires its binding to certain glycosaminoglycans naturally present on host cell membranes. We took advantage of this interaction to design biomimetic supramolecular hexagonal-shaped nanoassemblies composed of chondroitin sulfate having exalted anti-HSV-2 activity in comparison with native chondroitin sulfate. Nanoassemblies were formed by mixing hydrophobically-modified chondroitin sulfate with α-cyclodextrin in water. Optimization of alkyl chain length grafted on chondroitin sulfate and the ratio between hydrophobically-modified chondroitin sulfate and α-cyclodextrin showed that more cohesive and well-structured nanoassemblies were obtained using higher α-cyclodextrin concentration and longer alkyl chain lengths. A structure-activity relationship was found between anti-HSV-2 activity and the amphiphilic nature of hydrophobically-modified chondroitin sulfate. Also, antiviral activity of hexagonal nanoassemblies against HSV-2 was further improved in comparison with hydrophobically-modified chondroitin sulfate. This work suggests a new biomimetic formulation approach that can be extended to other heparan-sulfate-dependent viruses. © 2015 Elsevier Ltd. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The initial step in mucosal infection by the herpes simplex virus type 2 (HSV-2) requires its binding to certain glycosaminoglycans naturally present on host cell membranes. We took advantage of this interaction to design biomimetic supramolecular hexagonal-shaped nanoassemblies composed of chondroitin sulfate having exalted anti-HSV-2 activity in comparison with native chondroitin sulfate. Nanoassemblies were formed by mixing hydrophobically-modified chondroitin sulfate with α-cyclodextrin in water. Optimization of alkyl chain length grafted on chondroitin sulfate and the ratio between hydrophobically-modified chondroitin sulfate and α-cyclodextrin showed that more cohesive and well-structured nanoassemblies were obtained using higher α-cyclodextrin concentration and longer alkyl chain lengths. A structure-activity relationship was found between anti-HSV-2 activity and the amphiphilic nature of hydrophobically-modified chondroitin sulfate. Also, antiviral activity of hexagonal nanoassemblies against HSV-2 was further improved in comparison with hydrophobically-modified chondroitin sulfate. This work suggests a new biomimetic formulation approach that can be extended to other heparan-sulfate-dependent viruses. © 2015 Elsevier Ltd. All rights reserved. |
2015 |
Development of Bright Fluorescent Quadracyclic Adenine Analogues: TDDFT-Calculation Supported Rational Design Article de journal Anders Foller Larsen; Blaise Dumat; Moa S Wranne; Christopher P Lawson; Søren Preus; Mattias Bood; Henrik Gradén; L Marcus Wilhelmsson; Morten Grøtli Scientific Reports, 5 , p. 12653-12653, 2015. @article{FollerLarsen:2015, title = {Development of Bright Fluorescent Quadracyclic Adenine Analogues: TDDFT-Calculation Supported Rational Design}, author = {Anders Foller Larsen and Blaise Dumat and Moa S Wranne and Christopher P Lawson and S\oren Preus and Mattias Bood and Henrik Grad\'{e}n and L Marcus Wilhelmsson and Morten Gr\otli}, doi = {10.1038/srep12653}, year = {2015}, date = {2015-07-01}, journal = {Scientific Reports}, volume = {5}, pages = {12653-12653}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Feliciana Real Fernández; Margherita Di Pisa; Giada Rossi; Nicolas Auberger; Olivier Lequin; Maud Larregola; Amina Benchohra; Christelle Mansuy; Gerard Chassaing; Francesco Lolli; Joussef Hayek; Solange Lavielle; Paolo Rovero; Jean-Maurice Mallet; Anna Maria Papini Biopolymers, 104 (5), p. 560-576, 2015. @article{RealFernandez:2015, title = {Antibody Recognition in Multiple Sclerosis and Rett Syndrome Using a Collection of Linear and Cyclic N -Glucosylated Antigenic Probes: Antibody Recognition in Multiple Sclerosis and Rett Syndrome}, author = {Feliciana Real Fern\'{a}ndez and Margherita Di Pisa and Giada Rossi and Nicolas Auberger and Olivier Lequin and Maud Larregola and Amina Benchohra and Christelle Mansuy and Gerard Chassaing and Francesco Lolli and Joussef Hayek and Solange Lavielle and Paolo Rovero and Jean-Maurice Mallet and Anna Maria Papini}, doi = {10.1002/bip.22677}, year = {2015}, date = {2015-04-01}, journal = {Biopolymers}, volume = {104}, number = {5}, pages = {560-576}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Second-Generation Fluorescent Quadracyclic Adenine Analogues: Environment-Responsive Probes with Enhanced Brightness Article de journal Blaise Dumat; Mattias Bood; Moa S Wranne; Christopher P Lawson; Anders Foller Larsen; Søren Preus; Jens Streling; Henrik Gradén; Eric Wellner; Morten Grøtli; Marcus L Wilhelmsson Chemistry - A European Journal, 21 (10), p. 4039-4048, 2015. @article{Dumat:2015, title = {Second-Generation Fluorescent Quadracyclic Adenine Analogues: Environment-Responsive Probes with Enhanced Brightness}, author = {Blaise Dumat and Mattias Bood and Moa S Wranne and Christopher P Lawson and Anders Foller Larsen and S\oren Preus and Jens Streling and Henrik Grad\'{e}n and Eric Wellner and Morten Gr\otli and Marcus L Wilhelmsson}, doi = {10.1002/chem.201405759}, year = {2015}, date = {2015-03-01}, journal = {Chemistry - A European Journal}, volume = {21}, number = {10}, pages = {4039-4048}, abstract = {Fluorescent base analogues comprise a group of increasingly important molecules for the investigation of nucleic acid structure, dynamics, and interactions with other molecules. Herein, we report on the quantum chemical calculation aided design, synthesis, and characterization of four new putative quadracyclic adenine analogues. The compounds were efficiently synthesized from a common intermediate through a two-step pathway with the Suzuki-Miyaura coupling as the key step. Two of the compounds, qAN1 and qAN4, display brightnesses ($epsilonPhi$F ) of 1700 and 2300, respectively, in water and behave as wavelength-ratiometric pH probes under acidic conditions. The other two, qAN2 and qAN3, display lower brightnesses but exhibit polarity-sensitive dual-band emissions that could prove useful to investigate DNA structural changes induced by DNA-protein or -drug interactions. The four qANs are very promising microenvironment-sensitive fluorescent adenine analogues that display considerable brightness for such compounds.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Fluorescent base analogues comprise a group of increasingly important molecules for the investigation of nucleic acid structure, dynamics, and interactions with other molecules. Herein, we report on the quantum chemical calculation aided design, synthesis, and characterization of four new putative quadracyclic adenine analogues. The compounds were efficiently synthesized from a common intermediate through a two-step pathway with the Suzuki-Miyaura coupling as the key step. Two of the compounds, qAN1 and qAN4, display brightnesses ($epsilonPhi$F ) of 1700 and 2300, respectively, in water and behave as wavelength-ratiometric pH probes under acidic conditions. The other two, qAN2 and qAN3, display lower brightnesses but exhibit polarity-sensitive dual-band emissions that could prove useful to investigate DNA structural changes induced by DNA-protein or -drug interactions. The four qANs are very promising microenvironment-sensitive fluorescent adenine analogues that display considerable brightness for such compounds. |
Functionalizable red emitting calcium sensor bearing a 1,4-triazole chelating moiety Article de journal M Collot; C Wilms; J -M Mallet RSC Advances, 5 (9), p. 6993–7000, 2015. @article{Collot:2015, title = {Functionalizable red emitting calcium sensor bearing a 1,4-triazole chelating moiety}, author = {M Collot and C Wilms and J -M Mallet}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84920811584&doi=10.1039%2fc4ra12858c&partnerID=40&md5=0538c0c03e1684550eaf1e8d64cc8c1f}, doi = {10.1039/c4ra12858c}, year = {2015}, date = {2015-01-01}, journal = {RSC Advances}, volume = {5}, number = {9}, pages = {6993--7000}, abstract = {Herein we developed a functionalizable OFF-ON red emitting fluorescent calcium probe based on a new chelating system formed by CuAAC click chemistry (Huisgen cycloaddition). The pro-sensor 7 which is not sensitive to Ca2+, contains an alkyne moiety that, upon the click reaction, forms a chelating group involving the 1,4-triazole. Probe 10 exhibited good sensitivity towards calcium (Kd = 5.8 μM) and zinc (5.6 μM) with a high dynamic range (65 fold fluorescence increase), high quantum yield (0.59) and showed very low fluorescence enhancement in the presence of a high concentration of Mg2+. We extended this method and generated two dextran conjugates in order to compare their sensing properties with those of the molecular form of 10. © The Royal Society of Chemistry 2015.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Herein we developed a functionalizable OFF-ON red emitting fluorescent calcium probe based on a new chelating system formed by CuAAC click chemistry (Huisgen cycloaddition). The pro-sensor 7 which is not sensitive to Ca2+, contains an alkyne moiety that, upon the click reaction, forms a chelating group involving the 1,4-triazole. Probe 10 exhibited good sensitivity towards calcium (Kd = 5.8 μM) and zinc (5.6 μM) with a high dynamic range (65 fold fluorescence increase), high quantum yield (0.59) and showed very low fluorescence enhancement in the presence of a high concentration of Mg2+. We extended this method and generated two dextran conjugates in order to compare their sensing properties with those of the molecular form of 10. © The Royal Society of Chemistry 2015. |
H-Rubies, a new family of red emitting fluorescent pH sensors for living cells Article de journal G Despras; A I Zamaleeva; L Dardevet; C Tisseyre; J G Magalhaes; C Garner; M De Waard; S Amigorena; A Feltz; J -M Mallet; M Collot Chemical Science, 6 (10), p. 5928–5937, 2015. @article{Despras:2015, title = {H-Rubies, a new family of red emitting fluorescent pH sensors for living cells}, author = {G Despras and A I Zamaleeva and L Dardevet and C Tisseyre and J G Magalhaes and C Garner and M De Waard and S Amigorena and A Feltz and J -M Mallet and M Collot}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84941771218&doi=10.1039%2fc5sc01113b&partnerID=40&md5=522f013467ca99e17055b77088a0b804}, doi = {10.1039/c5sc01113b}, year = {2015}, date = {2015-01-01}, journal = {Chemical Science}, volume = {6}, number = {10}, pages = {5928--5937}, abstract = {Monitoring intracellular pH has drawn much attention due to its undeniably important function in cells. The widespread development of fluorescent imaging techniques makes pH sensitive fluorescent dyes valuable tools, especially red-emitting dyes which help to avoid the overcrowded green end of the spectral band. Herein, we present H-Rubies, a family of pH sensors based on a phenol moiety and a X-rhodamine fluorophore that display a bright red fluorescence upon acidification with pKtextlessinftextgreateratextless/inftextgreater values spanning from 4 to 9. Slight structural modifications led to dramatic changes in their physicochemical properties and a relationship between their structures, their ability to form H-aggregates, and their apparent pKtextlessinftextgreateratextless/inftextgreater was established. While molecular form H-Rubies can be used to monitor mitochondrial acidification of glioma cells, their functionalised forms were linked via click chemistry to dextrans or microbeads containing a near infrared Cy5 (Alexa-647) in order to provide ratiometric systems that were used to measure respectively the phagosomal and endosomal pH in macrophages (RAW 264.7 cells) using flow cytometry. © The Royal Society of Chemistry 2015.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Monitoring intracellular pH has drawn much attention due to its undeniably important function in cells. The widespread development of fluorescent imaging techniques makes pH sensitive fluorescent dyes valuable tools, especially red-emitting dyes which help to avoid the overcrowded green end of the spectral band. Herein, we present H-Rubies, a family of pH sensors based on a phenol moiety and a X-rhodamine fluorophore that display a bright red fluorescence upon acidification with pKtextlessinftextgreateratextless/inftextgreater values spanning from 4 to 9. Slight structural modifications led to dramatic changes in their physicochemical properties and a relationship between their structures, their ability to form H-aggregates, and their apparent pKtextlessinftextgreateratextless/inftextgreater was established. While molecular form H-Rubies can be used to monitor mitochondrial acidification of glioma cells, their functionalised forms were linked via click chemistry to dextrans or microbeads containing a near infrared Cy5 (Alexa-647) in order to provide ratiometric systems that were used to measure respectively the phagosomal and endosomal pH in macrophages (RAW 264.7 cells) using flow cytometry. © The Royal Society of Chemistry 2015. |
FRET-based nanobiosensors for imaging intracellular Ca2+ and Ħ+ microdomains Article de journal A I Zamaleeva; G Despras; C Luccardini; M Collot; M De Waard; M Oheim; J -M Mallet; A Feltz Sensors (Switzerland), 15 (9), p. 24662–24680, 2015. @article{Zamaleeva:2015, title = {FRET-based nanobiosensors for imaging intracellular Ca2+ and {H}+ microdomains}, author = {A I Zamaleeva and G Despras and C Luccardini and M Collot and M De Waard and M Oheim and J -M Mallet and A Feltz}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84942274997&doi=10.3390%2fs150924662&partnerID=40&md5=68dc9fd5142fca94995fcd7b97df4ca6}, doi = {10.3390/s150924662}, year = {2015}, date = {2015-01-01}, journal = {Sensors (Switzerland)}, volume = {15}, number = {9}, pages = {24662--24680}, abstract = {Semiconductor nanocrystals (NCs) or quantum dots (QDs) are luminous point emitters increasingly being used to tag and track biomolecules in biological/biomedical imaging. However, their intracellular use as highlighters of single-molecule localization and nanobiosensors reporting ion microdomains changes has remained a major challenge. Here, we report the design, generation and validation of FRET-based nanobiosensors for detection of intracellular Ca2+ and H+ transients. Our sensors combine a commercially available CANdot®565QD as an energy donor with, as an acceptor, our custom-synthesized red-emitting Ca2+ or H+ probes. These ‘Rubies’ are based on an extended rhodamine as afluorophore and a phenol or BAPTA (1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetra-acetic acid) for H+ or Ca2+ sensing, respectively, and additionally bear a linker arm for conjugation. QDs were stably functionalized using the same SH/maleimide crosslink chemistry for all desired reactants. Mixing ion sensor and cell-penetrating peptides (that facilitate cytoplasmic delivery) at the desired stoichiometric ratio produced controlled multi-conjugated assemblies. Multiple acceptors on the same central donor allow up-concentrating the ion sensor on the QD surface to concentrations higher than those that could be achieved in free solution, increasing FRET efficiency and improving the signal. We validate these nanosensors for the detection of intracellular Ca2+ and pH transients using live-cell fluorescence imaging. © 2015 by the authors; licensee MDPI, Basel, Switzerland.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Semiconductor nanocrystals (NCs) or quantum dots (QDs) are luminous point emitters increasingly being used to tag and track biomolecules in biological/biomedical imaging. However, their intracellular use as highlighters of single-molecule localization and nanobiosensors reporting ion microdomains changes has remained a major challenge. Here, we report the design, generation and validation of FRET-based nanobiosensors for detection of intracellular Ca2+ and H+ transients. Our sensors combine a commercially available CANdot®565QD as an energy donor with, as an acceptor, our custom-synthesized red-emitting Ca2+ or H+ probes. These ‘Rubies’ are based on an extended rhodamine as afluorophore and a phenol or BAPTA (1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetra-acetic acid) for H+ or Ca2+ sensing, respectively, and additionally bear a linker arm for conjugation. QDs were stably functionalized using the same SH/maleimide crosslink chemistry for all desired reactants. Mixing ion sensor and cell-penetrating peptides (that facilitate cytoplasmic delivery) at the desired stoichiometric ratio produced controlled multi-conjugated assemblies. Multiple acceptors on the same central donor allow up-concentrating the ion sensor on the QD surface to concentrations higher than those that could be achieved in free solution, increasing FRET efficiency and improving the signal. We validate these nanosensors for the detection of intracellular Ca2+ and pH transients using live-cell fluorescence imaging. © 2015 by the authors; licensee MDPI, Basel, Switzerland. |
Candida albicans β-1,2-mannosyltransferase Bmt3 prompts the elongation of the cell-wall phosphopeptidomannan Article de journal G Sfihi-Loualia; T Hurtaux; E Fabre; C Fradin; A Mée; M Pourcelot; E Maes; J Bouckaert; J -M Mallet; D Poulain; F Delplace; Y Guérardel Glycobiology, 26 (2), p. 203–214, 2015. @article{Sfihi-Loualia:2015, title = {Candida albicans β-1,2-mannosyltransferase Bmt3 prompts the elongation of the cell-wall phosphopeptidomannan}, author = {G Sfihi-Loualia and T Hurtaux and E Fabre and C Fradin and A M\'{e}e and M Pourcelot and E Maes and J Bouckaert and J -M Mallet and D Poulain and F Delplace and Y Gu\'{e}rardel}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84958973962&doi=10.1093%2fglycob%2fcwv094&partnerID=40&md5=836aa3e4a3780c3ecaeb8e5623aefd83}, doi = {10.1093/glycob/cwv094}, year = {2015}, date = {2015-01-01}, journal = {Glycobiology}, volume = {26}, number = {2}, pages = {203--214}, abstract = {β-1,2-Linked mannosides are expressed on numerous cell-wall glycoconjugates of the opportunistic pathogen yeast Candida albicans. Several studies evidenced their implication in the host-pathogen interaction and virulence mechanisms. In the present study, we characterized the in vitro activity of CaBmt3, a β-1,2-mannosyltransferase involved in the elongation of β-1,2-oligomannosides oligomers onto the cell-wall polymannosylated N-glycans. A recombinant soluble enzyme Bmt3p was produced in Pichia pastoris and its enzyme activity was investigated using natural and synthetic oligomannosides as potential acceptor substrates. Bmt3p was shown to exhibit an exquisite enzymatic specificity by adding a single terminal β-mannosyl residue to α-1,2-linked oligomannosides capped by a Manβ1-2Man motif. Furthermore, we demonstrated that the previously identified CaBmt1 and CaBmt3 efficiently act together to generate Manβ1-2Manβ1-2[Manα1-2]n sequence from α-1,2-linked oligomannosides onto exogenous and endogenous substrates. © 2015 The Author. Published by Oxford University Press. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } β-1,2-Linked mannosides are expressed on numerous cell-wall glycoconjugates of the opportunistic pathogen yeast Candida albicans. Several studies evidenced their implication in the host-pathogen interaction and virulence mechanisms. In the present study, we characterized the in vitro activity of CaBmt3, a β-1,2-mannosyltransferase involved in the elongation of β-1,2-oligomannosides oligomers onto the cell-wall polymannosylated N-glycans. A recombinant soluble enzyme Bmt3p was produced in Pichia pastoris and its enzyme activity was investigated using natural and synthetic oligomannosides as potential acceptor substrates. Bmt3p was shown to exhibit an exquisite enzymatic specificity by adding a single terminal β-mannosyl residue to α-1,2-linked oligomannosides capped by a Manβ1-2Man motif. Furthermore, we demonstrated that the previously identified CaBmt1 and CaBmt3 efficiently act together to generate Manβ1-2Manβ1-2[Manα1-2]n sequence from α-1,2-linked oligomannosides onto exogenous and endogenous substrates. © 2015 The Author. Published by Oxford University Press. All rights reserved. |
A new method for the determination of the nitrogen content of nitrocellulose based on the molar ratio of nitrite-to-nitrate ions released after alkaline hydrolysis Article de journal E Alinat; N Delaunay; X Archer; J -M Mallet; P Gareil Journal of Hazardous Materials, 286 (1), p. 92–99, 2015. @article{Alinat:2015, title = {A new method for the determination of the nitrogen content of nitrocellulose based on the molar ratio of nitrite-to-nitrate ions released after alkaline hydrolysis}, author = {E Alinat and N Delaunay and X Archer and J -M Mallet and P Gareil}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84937219620&doi=10.1016%2fj.jhazmat.2014.12.032&partnerID=40&md5=a1da8a9eb053326337df3469ce1fb3f3}, doi = {10.1016/j.jhazmat.2014.12.032}, year = {2015}, date = {2015-01-01}, journal = {Journal of Hazardous Materials}, volume = {286}, number = {1}, pages = {92--99}, abstract = {A new method was proposed to determine the nitrogen content of nitrocelluloses (NCs). It is based on the finding of a linear relationship between the nitrogen content and the molar ratio of nitrite-to-nitrate ions released after alkaline hydrolysis. Capillary electrophoresis was used to monitor the concentration of nitrite and nitrate ions. The influences of hydrolysis time and molar mass of NC on the molar ratio of nitrite-to-nitrate ions were investigated, and new insights into the understanding of the alkaline denitration mechanism of NCs, underlying this analytical strategy is provided. The method was then tested successfully with various explosive and non-explosive NC-containing samples such as various daily products and smokeless gunpowders. Inherently to its principle exploiting a concentration ratio, this method shows very good repeatability in the determination of nitrogen content in real samples with relative standard deviation (. n=. 3) inferior to 1.5%, and also provides very significant advantages with respect to sample extraction, analysis time (1. h for alkaline hydrolysis, 3. min for electrophoretic separation), which was about 5 times shorter than for the classical Devarda's method, currently used in industry, and safety conditions (no need for preliminary drying NC samples, mild hydrolysis conditions with 1. M sodium hydroxide for 1. h at 60. °C). © 2014 Elsevier B.V.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A new method was proposed to determine the nitrogen content of nitrocelluloses (NCs). It is based on the finding of a linear relationship between the nitrogen content and the molar ratio of nitrite-to-nitrate ions released after alkaline hydrolysis. Capillary electrophoresis was used to monitor the concentration of nitrite and nitrate ions. The influences of hydrolysis time and molar mass of NC on the molar ratio of nitrite-to-nitrate ions were investigated, and new insights into the understanding of the alkaline denitration mechanism of NCs, underlying this analytical strategy is provided. The method was then tested successfully with various explosive and non-explosive NC-containing samples such as various daily products and smokeless gunpowders. Inherently to its principle exploiting a concentration ratio, this method shows very good repeatability in the determination of nitrogen content in real samples with relative standard deviation (. n=. 3) inferior to 1.5%, and also provides very significant advantages with respect to sample extraction, analysis time (1. h for alkaline hydrolysis, 3. min for electrophoretic separation), which was about 5 times shorter than for the classical Devarda's method, currently used in industry, and safety conditions (no need for preliminary drying NC samples, mild hydrolysis conditions with 1. M sodium hydroxide for 1. h at 60. °C). © 2014 Elsevier B.V. |
Hypervalent-Iodine-Mediated Synthesis of 1,2-Dispirodienones: Experimental and Theoretical Investigations Article de journal T Hromjakova; P Retailleau; L Grimaud; V Gandon; L Chabaud; C Guillou European Journal of Organic Chemistry, 2015 (34), p. 7494–7503, 2015. @article{Hromjakova:2015, title = {Hypervalent-Iodine-Mediated Synthesis of 1,2-Dispirodienones: Experimental and Theoretical Investigations}, author = {T Hromjakova and P Retailleau and L Grimaud and V Gandon and L Chabaud and C Guillou}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84954457910&doi=10.1002%2fejoc.201501160&partnerID=40&md5=c562e8d5892730fd94160b4110ab2a80}, doi = {10.1002/ejoc.201501160}, year = {2015}, date = {2015-01-01}, journal = {European Journal of Organic Chemistry}, volume = {2015}, number = {34}, pages = {7494--7503}, abstract = {The oxidation of phenol acetanilides mediated by hypervalent iodine is described. The transformation proceeds through the formation of a carbocationic species that evolves either into a [6,5,6]-tricyclic compound (1,2-dispirodienone) or a [6,6,6]-tricyclic compound (aryl spirodienone). In most examples, the 1,2-dispirodienones are obtained in good yields. In some cases, depending on the substitution pattern of the phenol acetanilides and the reaction conditions, aryl spirodienones are formed. We performed electrochemical experiments on a 1,2-dispirodienone to study its redox properties. These data provide evidence that the 1,2-dispirodienone can ring-open and ring-close under redox conditions. The hypervalent-iodine-mediated oxidation of phenol acetanilides to 1,2-dispirodienones was rationalized on the basis of density functional theory (DFT) calculations. In addition, these DFT computations suggest that the formation of the aryl spirodienones occurs by a stepwise reaction pathway, which first involves an ipso attack to yield a [6,5,6]-tricyclic carbocationic intermediate and then a 1,2-sigmatropic shift of the bond that connects the two six-membered rings. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The oxidation of phenol acetanilides mediated by hypervalent iodine is described. The transformation proceeds through the formation of a carbocationic species that evolves either into a [6,5,6]-tricyclic compound (1,2-dispirodienone) or a [6,6,6]-tricyclic compound (aryl spirodienone). In most examples, the 1,2-dispirodienones are obtained in good yields. In some cases, depending on the substitution pattern of the phenol acetanilides and the reaction conditions, aryl spirodienones are formed. We performed electrochemical experiments on a 1,2-dispirodienone to study its redox properties. These data provide evidence that the 1,2-dispirodienone can ring-open and ring-close under redox conditions. The hypervalent-iodine-mediated oxidation of phenol acetanilides to 1,2-dispirodienones was rationalized on the basis of density functional theory (DFT) calculations. In addition, these DFT computations suggest that the formation of the aryl spirodienones occurs by a stepwise reaction pathway, which first involves an ipso attack to yield a [6,5,6]-tricyclic carbocationic intermediate and then a 1,2-sigmatropic shift of the bond that connects the two six-membered rings. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. |
Transition-Metal-Free α-Arylation of Enolizable Aryl Ketones and Mechanistic Evidence for a Radical Process Article de journal M Pichette Drapeau; I Fabre; L Grimaud; I Ciofini; T Ollevier; M Taillefer Angewandte Chemie - International Edition, 54 (36), p. 10587–10591, 2015. @article{PichetteDrapeau:2015, title = {Transition-Metal-Free α-Arylation of Enolizable Aryl Ketones and Mechanistic Evidence for a Radical Process}, author = {M Pichette Drapeau and I Fabre and L Grimaud and I Ciofini and T Ollevier and M Taillefer}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940446640&doi=10.1002%2fanie.201502332&partnerID=40&md5=5aad4174f11c138275502b734114180a}, doi = {10.1002/anie.201502332}, year = {2015}, date = {2015-01-01}, journal = {Angewandte Chemie - International Edition}, volume = {54}, number = {36}, pages = {10587--10591}, abstract = {The α-arylation of enolizable aryl ketones can be carried out with aryl halides under transition-metal-free conditions using KOtBu in DMF. The α-aryl ketones thus obtained can be used for step- and cost-economic syntheses of fused heterocycles and Tamoxifen. Mechanistic studies demonstrate the synergetic role of base and solvent for the initiation of the radical process. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The α-arylation of enolizable aryl ketones can be carried out with aryl halides under transition-metal-free conditions using KOtBu in DMF. The α-aryl ketones thus obtained can be used for step- and cost-economic syntheses of fused heterocycles and Tamoxifen. Mechanistic studies demonstrate the synergetic role of base and solvent for the initiation of the radical process. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. |
Titanium-Mediated Cyclopropanation of Nitriles with Unsaturated Grignard Reagents: Application to the Synthesis of Constrained Lysine Derivatives Article de journal G Forcher; N Clousier; A Beauseigneur; P Setzer; F Boeda; M S M Pearson-Long; P Karoyan; J Szymoniak; P Bertus Synthesis (Germany), 47 (7), p. 992–1006, 2015. @article{Forcher:2015, title = {Titanium-Mediated Cyclopropanation of Nitriles with Unsaturated Grignard Reagents: Application to the Synthesis of Constrained Lysine Derivatives}, author = {G Forcher and N Clousier and A Beauseigneur and P Setzer and F Boeda and M S M Pearson-Long and P Karoyan and J Szymoniak and P Bertus}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84949130137&doi=10.1055%2fs-0034-1379978&partnerID=40&md5=896720112382568d95185db52f84b732}, doi = {10.1055/s-0034-1379978}, year = {2015}, date = {2015-01-01}, journal = {Synthesis (Germany)}, volume = {47}, number = {7}, pages = {992--1006}, abstract = {A comparative study of the titanium-mediated cyclopropanation of (benzyloxy)acetonitrile and Boc-protected cyanohydrin using unsaturated Grignard reagents (but-3-enyl- and pent-4-enylmagnesium bromides) is described. The best conditions to provide the cis and trans isomers of cyclopropylamines bearing unsaturation were identified and the alkene moiety was subjected to chemical modifications, as shown by the synthesis of orthogonally protected cis- and trans-2,3-methanolysine, cis-2,3-methanoornithine, and cis-2,3-methanohomo-lysine. © Georg Thieme Verlag.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A comparative study of the titanium-mediated cyclopropanation of (benzyloxy)acetonitrile and Boc-protected cyanohydrin using unsaturated Grignard reagents (but-3-enyl- and pent-4-enylmagnesium bromides) is described. The best conditions to provide the cis and trans isomers of cyclopropylamines bearing unsaturation were identified and the alkene moiety was subjected to chemical modifications, as shown by the synthesis of orthogonally protected cis- and trans-2,3-methanolysine, cis-2,3-methanoornithine, and cis-2,3-methanohomo-lysine. © Georg Thieme Verlag. |
CD47 Agonist Peptides Induce Programmed Cell Death in Refractory Chronic Lymphocytic Leukemia B Cells via PLCγ1 Activation: Evidence from Mice and Humans Article de journal A -C Martinez-Torres; C Quiney; T Attout; H Boullet; L Herbi; L Vela; S Barbier; D Chateau; E Chapiro; F Nguyen-Khac; F Davi; M Le Garff-Tavernier; R Moumné; M Sarfati; P Karoyan; H Merle-Béral; P Launay; S A Susin PLoS Medicine, 12 (3), 2015. @article{Martinez-Torres:2015, title = {CD47 Agonist Peptides Induce Programmed Cell Death in Refractory Chronic Lymphocytic Leukemia B Cells via PLCγ1 Activation: Evidence from Mice and Humans}, author = {A -C Martinez-Torres and C Quiney and T Attout and H Boullet and L Herbi and L Vela and S Barbier and D Chateau and E Chapiro and F Nguyen-Khac and F Davi and M Le Garff-Tavernier and R Moumn\'{e} and M Sarfati and P Karoyan and H Merle-B\'{e}ral and P Launay and S A Susin}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84926512944&doi=10.1371%2fjournal.pmed.1001796&partnerID=40&md5=d6d0c23386f4e276919f9360d0bf5e83}, doi = {10.1371/journal.pmed.1001796}, year = {2015}, date = {2015-01-01}, journal = {PLoS Medicine}, volume = {12}, number = {3}, abstract = {Chronic lymphocytic leukemia (CLL), the most common adulthood leukemia, is characterized by the accumulation of abnormal CD5+ B lymphocytes, which results in a progressive failure of the immune system. Despite intense research efforts, drug resistance remains a major cause of treatment failure in CLL, particularly in patients with dysfunctional TP53. The objective of our work was to identify potential approaches that might overcome CLL drug refractoriness by examining the pro-apoptotic potential of targeting the cell surface receptor CD47 with serum-stable agonist peptides. In peripheral blood samples collected from 80 patients with CLL with positive and adverse prognostic features, we performed in vitro genetic and molecular analyses that demonstrate that the targeting of CD47 with peptides derived from the C-terminal domain of thrombospondin-1 efficiently kills the malignant CLL B cells, including those from high-risk individuals with a dysfunctional TP53 gene, while sparing the normal T and B lymphocytes from the CLL patients. Further studies reveal that the differential response of normal B lymphocytes, collected from 20 healthy donors, and leukemic B cells to CD47 peptide targeting results from the sustained activation in CLL B cells of phospholipase C gamma-1 (PLCγ1), a protein that is significantly over-expressed in CLL. Once phosphorylated at tyrosine 783, PLCγ1 enables a Ca2+-mediated, caspase-independent programmed cell death (PCD) pathway that is not down-modulated by the lymphocyte microenvironment. Accordingly, down-regulation of PLCγ1 or pharmacological inhibition of PLCγ1 phosphorylation abolishes CD47-mediated killing. Additionally, in a CLL-xenograft model developed in NOD/scid gamma mice, we demonstrate that the injection of CD47 agonist peptides reduces tumor burden without inducing anemia or toxicity in blood, liver, or kidney. The limitations of our study are mainly linked to the affinity of the peptides targeting CD47, which might be improved to reach the standard requirements in drug development, and the lack of a CLL animal model that fully mimics the human disease. Our work provides substantial progress in (i) the development of serum-stable CD47 agonist peptides that are highly effective at inducing PCD in CLL, (ii) the understanding of the molecular events regulating a novel PCD pathway that overcomes CLL apoptotic avoidance, (iii) the identification of PLCγ1 as an over-expressed protein in CLL B cells, and (iv) the description of a novel peptide-based strategy against CLL. © 2015 Martinez-Torres et al.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Chronic lymphocytic leukemia (CLL), the most common adulthood leukemia, is characterized by the accumulation of abnormal CD5+ B lymphocytes, which results in a progressive failure of the immune system. Despite intense research efforts, drug resistance remains a major cause of treatment failure in CLL, particularly in patients with dysfunctional TP53. The objective of our work was to identify potential approaches that might overcome CLL drug refractoriness by examining the pro-apoptotic potential of targeting the cell surface receptor CD47 with serum-stable agonist peptides. In peripheral blood samples collected from 80 patients with CLL with positive and adverse prognostic features, we performed in vitro genetic and molecular analyses that demonstrate that the targeting of CD47 with peptides derived from the C-terminal domain of thrombospondin-1 efficiently kills the malignant CLL B cells, including those from high-risk individuals with a dysfunctional TP53 gene, while sparing the normal T and B lymphocytes from the CLL patients. Further studies reveal that the differential response of normal B lymphocytes, collected from 20 healthy donors, and leukemic B cells to CD47 peptide targeting results from the sustained activation in CLL B cells of phospholipase C gamma-1 (PLCγ1), a protein that is significantly over-expressed in CLL. Once phosphorylated at tyrosine 783, PLCγ1 enables a Ca2+-mediated, caspase-independent programmed cell death (PCD) pathway that is not down-modulated by the lymphocyte microenvironment. Accordingly, down-regulation of PLCγ1 or pharmacological inhibition of PLCγ1 phosphorylation abolishes CD47-mediated killing. Additionally, in a CLL-xenograft model developed in NOD/scid gamma mice, we demonstrate that the injection of CD47 agonist peptides reduces tumor burden without inducing anemia or toxicity in blood, liver, or kidney. The limitations of our study are mainly linked to the affinity of the peptides targeting CD47, which might be improved to reach the standard requirements in drug development, and the lack of a CLL animal model that fully mimics the human disease. Our work provides substantial progress in (i) the development of serum-stable CD47 agonist peptides that are highly effective at inducing PCD in CLL, (ii) the understanding of the molecular events regulating a novel PCD pathway that overcomes CLL apoptotic avoidance, (iii) the identification of PLCγ1 as an over-expressed protein in CLL B cells, and (iv) the description of a novel peptide-based strategy against CLL. © 2015 Martinez-Torres et al. |
Unsaturated acyl chains dramatically enhanced cellular uptake by direct translocation of a minimalist oligo-arginine lipopeptide Article de journal J -M Swiecicki; M Di Pisa; F Lippi; S Chwetzoff; C Mansuy; G Trugnan; G Chassaing; S Lavielle; F Burlina Chemical Communications, 51 (78), p. 14656–14659, 2015. @article{Swiecicki:2015, title = {Unsaturated acyl chains dramatically enhanced cellular uptake by direct translocation of a minimalist oligo-arginine lipopeptide}, author = {J -M Swiecicki and M Di Pisa and F Lippi and S Chwetzoff and C Mansuy and G Trugnan and G Chassaing and S Lavielle and F Burlina}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84941928625&doi=10.1039%2fc5cc06116d&partnerID=40&md5=288261f987c6ebd4b9aa0b0ec89f2154}, doi = {10.1039/c5cc06116d}, year = {2015}, date = {2015-01-01}, journal = {Chemical Communications}, volume = {51}, number = {78}, pages = {14656--14659}, abstract = {The recurring issue with cell penetrating peptides is how to increase direct translocation vs. endocytosis, to avoid premature degradation. Acylation by a cis unsaturated chain (C22:6) of a short cationic peptide provides a new rational design to favour diffuse cytosolic and dense Golgi localisations. © The Royal Society of Chemistry 2015.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The recurring issue with cell penetrating peptides is how to increase direct translocation vs. endocytosis, to avoid premature degradation. Acylation by a cis unsaturated chain (C22:6) of a short cationic peptide provides a new rational design to favour diffuse cytosolic and dense Golgi localisations. © The Royal Society of Chemistry 2015. |
Accumulation of cell-penetrating peptides in large unilamellar vesicles: A straightforward screening assay for investigating the internalization mechanism Article de journal J -M Swiecicki; M Di Pisa; F Burlina; P Lécorché; C Mansuy; G Chassaing; S Lavielle Biopolymers, 104 (5), p. 533–543, 2015. @article{Swiecicki:2015a, title = {Accumulation of cell-penetrating peptides in large unilamellar vesicles: A straightforward screening assay for investigating the internalization mechanism}, author = {J -M Swiecicki and M Di Pisa and F Burlina and P L\'{e}corch\'{e} and C Mansuy and G Chassaing and S Lavielle}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84975261080&doi=10.1002%2fbip.22652&partnerID=40&md5=b7e09c0b307479f4671edad8a6ef121d}, doi = {10.1002/bip.22652}, year = {2015}, date = {2015-01-01}, journal = {Biopolymers}, volume = {104}, number = {5}, pages = {533--543}, abstract = {The internalization of cell-penetrating peptides (CPPs) into liposomes (large unilamellar vesicles, LUVs) was studied with a rapid and robust procedure based on the quenching of a small fluorescent probe, 7-nitrobenz-2-oxa-1,3-diazole (NBD). Quenching can be achieved by reduction with dithionite or by pH jump. LUVs with different compositions of phospholipids (PLs) were used to screen the efficacy of different CPPs. In order to "validate" the composition of the membrane models, a control cationic peptide, which does not enter eukaryotic cells, was included in the study. It was found that pure DOPG or DOPG within ternary mixtures with cholesterol are the most appropriate models for studying CPP translocation. An anionic lipid, such as DOPG, is required for the adsorption of the basic peptides on the surface of LUVs. In addition, it acts as transfer agent through the lipid bilayer. A fluid phase and/or the presence of phase defects also appear mandatory for the internalization to occur. The neutralization of charges within an inverted micelle demonstrated in the case of DOPG and also proposed for a ternary mixture of PLs might not be the only mechanism for the CPP translocation. Finally, it is shown that oleic acid facilitates the entry inside LUVs in gel phase of a series of cationic peptides including CPPs and also the negative control peptide PKCi. © 2015 Wiley Periodicals, Inc.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The internalization of cell-penetrating peptides (CPPs) into liposomes (large unilamellar vesicles, LUVs) was studied with a rapid and robust procedure based on the quenching of a small fluorescent probe, 7-nitrobenz-2-oxa-1,3-diazole (NBD). Quenching can be achieved by reduction with dithionite or by pH jump. LUVs with different compositions of phospholipids (PLs) were used to screen the efficacy of different CPPs. In order to "validate" the composition of the membrane models, a control cationic peptide, which does not enter eukaryotic cells, was included in the study. It was found that pure DOPG or DOPG within ternary mixtures with cholesterol are the most appropriate models for studying CPP translocation. An anionic lipid, such as DOPG, is required for the adsorption of the basic peptides on the surface of LUVs. In addition, it acts as transfer agent through the lipid bilayer. A fluid phase and/or the presence of phase defects also appear mandatory for the internalization to occur. The neutralization of charges within an inverted micelle demonstrated in the case of DOPG and also proposed for a ternary mixture of PLs might not be the only mechanism for the CPP translocation. Finally, it is shown that oleic acid facilitates the entry inside LUVs in gel phase of a series of cationic peptides including CPPs and also the negative control peptide PKCi. © 2015 Wiley Periodicals, Inc. |
Concentration-dependent and surface-assisted self-assembly properties of a bioactive estrogen receptor α-derived peptide Article de journal F S Ruggeri; C Byrne; L Khemtemourian; G Ducouret; G Dietler; Y Jacquot Journal of Peptide Science, 21 (2), p. 95–104, 2015. @article{Ruggeri:2015, title = {Concentration-dependent and surface-assisted self-assembly properties of a bioactive estrogen receptor α-derived peptide}, author = {F S Ruggeri and C Byrne and L Khemtemourian and G Ducouret and G Dietler and Y Jacquot}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84921823563&doi=10.1002%2fpsc.2730&partnerID=40&md5=eb091e7246c00864fc9bba4b932056de}, doi = {10.1002/psc.2730}, year = {2015}, date = {2015-01-01}, journal = {Journal of Peptide Science}, volume = {21}, number = {2}, pages = {95--104}, abstract = {We have synthesized a 17-mer peptide (ERα17p) that is issued from the hinge region of the estrogen receptor α and which activates the proliferation of breast carcinoma cells in steroid-deprived conditions. In the present paper, we show that at a concentration of ∼50 μM, it rapidly forms amyloid-like fibrils with the assistance of electrostatic interactions and that at higher concentrations, it spontaneously forms a hydrogel. By using biophysical, spectral and rheological techniques, we have explored the structural, biophysical and mechanical characteristics of ERα17p with respect to fibril formation and gelation. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We have synthesized a 17-mer peptide (ERα17p) that is issued from the hinge region of the estrogen receptor α and which activates the proliferation of breast carcinoma cells in steroid-deprived conditions. In the present paper, we show that at a concentration of ∼50 μM, it rapidly forms amyloid-like fibrils with the assistance of electrostatic interactions and that at higher concentrations, it spontaneously forms a hydrogel. By using biophysical, spectral and rheological techniques, we have explored the structural, biophysical and mechanical characteristics of ERα17p with respect to fibril formation and gelation. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd. |
The sequence Pro295-Thr311 of the hinge region of oestrogen receptor α is involved in ERK1/2 activation via GPR30 in leiomyoma cells Article de journal D Leiber; F Burlina; C Byrne; P Robin; C Piesse; L Gonzalez; G Leclercq; Z Tanfin; Y Jacquot Biochemical Journal, 472 (1), p. 97–109, 2015. @article{Leiber:2015, title = {The sequence Pro295-Thr311 of the hinge region of oestrogen receptor α is involved in ERK1/2 activation via GPR30 in leiomyoma cells}, author = {D Leiber and F Burlina and C Byrne and P Robin and C Piesse and L Gonzalez and G Leclercq and Z Tanfin and Y Jacquot}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84945944261&doi=10.1042%2fBJ20150744&partnerID=40&md5=aaba841e02aee4bc64eb82d540a4d782}, doi = {10.1042/BJ20150744}, year = {2015}, date = {2015-01-01}, journal = {Biochemical Journal}, volume = {472}, number = {1}, pages = {97--109}, abstract = {The ERα (oestrogen receptor α)-derived peptide ERα17p activates rapid signalling events in breast carcinoma cells under steroid-deprived conditions. In the present study, we investigated its effects in ELT3 leiomyoma cells under similar conditions. We show that it activates ERK1/2 (extracellular-signal-regulated kinase 1/2), the Gαi protein, the trans-activation of EGFR (epidermal growth factor receptor) and, finally, cell proliferation. It is partially internalized in cells and induces membrane translocation of β-arrestins. The activation of ERK1/2 is abolished by the GPR30 (G-protein-coupled receptor 30) antagonist G15 and GPR30 siRNA. When ERα is down-regulated by prolonged treatment with E2 (oestradiol) or specific ERα siRNA, the peptide response is blunted. Thus the simultaneous presence of GPR30 and ERα is required for the action of ERα17p. In addition, its PLM sequence, which interferes with the formation of the ERα-calmodulin complex, appears to be requisite for the phosphorylation of ERK1/2 and cell proliferation. Hence ERα17p is, to our knowledge, the first known peptide targeting ERα-GPR30 membrane cross-talk and the subsequent receptormediated biological effects. © 2015 Authors; published by Portland Press Limited.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The ERα (oestrogen receptor α)-derived peptide ERα17p activates rapid signalling events in breast carcinoma cells under steroid-deprived conditions. In the present study, we investigated its effects in ELT3 leiomyoma cells under similar conditions. We show that it activates ERK1/2 (extracellular-signal-regulated kinase 1/2), the Gαi protein, the trans-activation of EGFR (epidermal growth factor receptor) and, finally, cell proliferation. It is partially internalized in cells and induces membrane translocation of β-arrestins. The activation of ERK1/2 is abolished by the GPR30 (G-protein-coupled receptor 30) antagonist G15 and GPR30 siRNA. When ERα is down-regulated by prolonged treatment with E2 (oestradiol) or specific ERα siRNA, the peptide response is blunted. Thus the simultaneous presence of GPR30 and ERα is required for the action of ERα17p. In addition, its PLM sequence, which interferes with the formation of the ERα-calmodulin complex, appears to be requisite for the phosphorylation of ERK1/2 and cell proliferation. Hence ERα17p is, to our knowledge, the first known peptide targeting ERα-GPR30 membrane cross-talk and the subsequent receptormediated biological effects. © 2015 Authors; published by Portland Press Limited. |
When cationic cell-penetrating peptides meet hydrocarbons to enhance in-cell cargo delivery Article de journal M D Pisa; G Chassaing; J -M Swiecicki Journal of Peptide Science, 21 (5), p. 356–369, 2015. @article{Pisa:2015, title = {When cationic cell-penetrating peptides meet hydrocarbons to enhance in-cell cargo delivery}, author = {M D Pisa and G Chassaing and J -M Swiecicki}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84928808409&doi=10.1002%2fpsc.2755&partnerID=40&md5=31ff1ae39e96ac1184e2f12c70e0e708}, doi = {10.1002/psc.2755}, year = {2015}, date = {2015-01-01}, journal = {Journal of Peptide Science}, volume = {21}, number = {5}, pages = {356--369}, abstract = {Cell-penetrating peptides (CPPs) are short sequences often rich in cationic residues with the remarkable ability to cross cell membranes. In the past 20 years, CPPs have gained wide interest and have found numerous applications in the delivery of bioactive cargoes to the cytosol and even the nucleus of living cells. The covalent or non-covalent addition of hydrocarbon moieties to cationic CPPs alters the hydrophobicity/hydrophilicity balance in their sequence. Such perturbation dramatically influences their interaction with the cell membrane, might induce self-assembling properties and modifies their intracellular trafficking. In particular, the introduction of lipophilic moieties changes the subcellular distribution of CPPs and might result in a dramatically increase of the internalization yield of the co-transported cargoes. Herein, we offer an overview of different aspects of the recent findings concerning the properties of CPPs covalently or non-covalently associated to hydrocarbons. We will focus on the impact of the hydrocarbon moieties on the delivery of various cargoes, either covalently or non-covalently bound to the modified CPPs. We will also provide some key elements to rationalize the influence of the hydrocarbons moieties on the cellular uptake. Furthermore, the recent in vitro and in vivo successful applications of acylated CPPs will be summarized to provide a broad view of the versatility of these modified CPPs as small-molecules and oligonucleotides vectors. Copyright © 2015 European Peptide Society and John Wiley & Sons, Ltd.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Cell-penetrating peptides (CPPs) are short sequences often rich in cationic residues with the remarkable ability to cross cell membranes. In the past 20 years, CPPs have gained wide interest and have found numerous applications in the delivery of bioactive cargoes to the cytosol and even the nucleus of living cells. The covalent or non-covalent addition of hydrocarbon moieties to cationic CPPs alters the hydrophobicity/hydrophilicity balance in their sequence. Such perturbation dramatically influences their interaction with the cell membrane, might induce self-assembling properties and modifies their intracellular trafficking. In particular, the introduction of lipophilic moieties changes the subcellular distribution of CPPs and might result in a dramatically increase of the internalization yield of the co-transported cargoes. Herein, we offer an overview of different aspects of the recent findings concerning the properties of CPPs covalently or non-covalently associated to hydrocarbons. We will focus on the impact of the hydrocarbon moieties on the delivery of various cargoes, either covalently or non-covalently bound to the modified CPPs. We will also provide some key elements to rationalize the influence of the hydrocarbons moieties on the cellular uptake. Furthermore, the recent in vitro and in vivo successful applications of acylated CPPs will be summarized to provide a broad view of the versatility of these modified CPPs as small-molecules and oligonucleotides vectors. Copyright © 2015 European Peptide Society and John Wiley & Sons, Ltd. |