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Quentin Nevers - One of the best experts on this subject based on the ideXlab platform.
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Développement d'une nouvelle famille d'inhibiteurs de cyclophilines à large spectre antiviral et étude de leurs mécanismes d'action dans les infections par le Virus de l'Hépatite C et les Coronavirus.
2018Co-Authors: Quentin NeversAbstract:Les dernières décennies ont été marquées par l’émergence ou la réémergence d’un nombre croissant de virus pathogènes. Malheureusement, les antiviraux actuellement sur le marché ciblent un nombre restreint de virus ; il y a donc un besoin urgent de développer des antiviraux à large spectre. Les cyclophilines sont des protéines cellulaires impliquées dans un grand nombre de processus biologiques, qui possèdent une activité enzymatique peptidyl-prolyl cis-trans isomérase (PPIase). Elles sont également impliquées dans la réplication de virus appartenant à des familles éloignées et constituent donc une cible de choix pour le développement d'antiviraux à large spectre. Toutefois, les inhibiteurs de cyclophilines disponibles possèdent de nombreux inconvénients qui rendent leur utilisation clinique difficile.Par une stratégie de "fragment-based drug design", nous avons généré une nouvelle famille d'inhibiteurs de cyclophilines, les SMCypI ("Small-Molecule Cyclophilin Inhibitors"), complètement différents de tous les inhibiteurs de cyclophilines existants. La cristallographie de ces composés a montré qu'ils se fixaient dans les deux poches voisines du site actif des cyclophilines et qu'ils inhibaient leur activité PPIase. Ces composés n’étaient pas immunosuppressifs et bloquaient in vitro l'infection par le VIH, le VHC et les Coronavirus.L'activité anti-VHC du C31, composé le plus actif sur l'activité PPIase des cyclophilines, a été caractérisée. Le C31 était un inhibiteur pan-génotypique du VHC, doté d’une haute barrière contre la résistance et présentant une activité additive avec les inhibiteurs du VHC approuvés. Nous avons montré que le C31 bloquait l'infection par le VHC en rompant l'interaction entre la protéine virale NS5A et la cyclophiline A de façon PPIase-dépendante. Enfin, le C31 était actif sur la réplication des virus zika, de la dengue, de la fièvre jaune et du Nil Occidental.L'activité des SMCypI a été caractérisée sur l'infection par le Coronavirus 229E. De manière intéressante, l’inhibition de l’activité PPIase était nécessaire, mais pas suffisante pour l’activité antivirale. Une étude de la relation structure-activité des composés a révélé qu'un groupement chimique situé à l'interface entre les deux poches du site actif des cyclophilines jouait un rôle clé dans l'effet anti-coronavirus. Le F836 a été identifié comme le composé le plus actif, qui bloquait l'effet cytopathique et la quantité d'ARN du HCoV-229E avec la même efficacité que l'alisporivir, sans toxicité associée. Ce composé bloquait l'entrée du HCoV-229E après l'attachement du virus à la surface cellulaire, et était également actif sur l'entrée des HCoV-OC43 et du MERS-CoV. Nous avons par la suite démontré l’association de la cyclophiline A avec les particules virales. Par l'utilisation de la technologie CRISPR-Cas9, des cellules invalidées pour la cyclophiline A ont été générées. La cyclophiline A apparaissait nécessaire pour l'infection par HCoV-229E et la cible de l'effet antiviral du F836.Les SMCypI constituent un outil pour la compréhension des mécanismes par lesquels les cyclophilines modulent les infections virales et représentent des candidats crédibles pour le développement futur d'antiviraux à large spectre.
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Characterization of the Anti-Hepatitis C Virus Activity of New Nonpeptidic Small-Molecule Cyclophilin Inhibitors with the Potential for Broad Anti- Flaviviridae Activity
Antimicrobial Agents and Chemotherapy, 2018Co-Authors: Quentin Nevers, Nazim Ahnou, Rozenn Brillet, Isaac Ruiz, Flora Donati, Laurent Softic, Maxime Chazal, Nolwenn Jouvenet, Slim Fourati, Camille BaudessonAbstract:Although members of the Flaviviridae display high incidence, morbidity, and mortality rates, the development of specific antiviral drugs for each virus is unlikely. Cyclophilins, a family of host peptidyl-prolyl cis-trans isomerases (PPIases), play a pivotal role in the life cycles of many viruses and therefore represent an attractive target for broad-spectrum antiviral development. We report here the pangenotypic anti-hepatitis C virus (HCV) activity of a small-molecule cyclophilin inhibitor (SMCypI). Mechanistic and modeling studies revealed that the SMCypI bound to cyclophilin A in competition with cyclosporine (CsA), inhibited its PPIase activity, and disrupted the CypA-nonstructural protein 5A (NS5A) interaction. Resistance selection showed that the lead SMCypI hardly selected amino acid substitutions conferring low-level or no resistance in vitro. Interestingly, the SMCypI selected D320E and Y321H substitutions, located in domain II of the NS5A protein. These substitutions were previously associated with low-level resistance to cyclophilin inhibitors such as alisporivir. Finally, the SMCypI inhibited the replication of other members of the Flaviviridae family with higher 50% effective concentrations (EC50s) than for HCV. Thus, because of its chemical plasticity and simplicity of synthesis, our new family of SMCypIs represents a promising new class of drugs with the potential for broad-spectrum anti-Flaviviridae activity as well as an invaluable tool to explore the role of Cyclophilins in viral life cycles.
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Fragment-based discovery of a new family of non-peptidic small-molecule cyclophilin inhibitors with potent antiviral activities
Nature Communications, 2016Co-Authors: Abdelhakim Ahmed-belkacem, Quentin Nevers, Lionel Colliandre, Nazim Ahnou, Muriel Gelin, Yannick Bessin, Rozenn Brillet, Olivier Cala, Dominique Douguet, William BourguetAbstract:Cyclophilins are peptidyl-prolyl cis/trans isomerases (PPIase) that catalyse the interconversion of the peptide bond at proline residues. Several Cyclophilins play a pivotal role in the life cycle of a number of viruses. The existing cyclophilin inhibitors, all derived from cyclosporine A or sanglifehrin A, have disadvantages, including their size, potential for side effects unrelated to cyclophilin inhibition and drug–drug interactions, unclear antiviral spectrum and manufacturing issues. Here we use a fragment-based drug discovery approach using nucleic magnetic resonance, X-ray crystallography and structure-based compound optimization to generate a new family of non-peptidic, small-molecule cyclophilin inhibitors with potent in vitro PPIase inhibitory activity and antiviral activity against hepatitis C virus, human immunodeficiency virus and coronaviruses. This family of compounds has the potential for broad-spectrum, high-barrier-to-resistance treatment of viral infections.
Nevers Quentin - One of the best experts on this subject based on the ideXlab platform.
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Développement d'une nouvelle famille d'inhibiteurs de cyclophilines à large spectre antiviral et étude de leurs mécanismes d'action dans les infections par le Virus de l'Hépatite C et les Coronavirus.
HAL CCSD, 2018Co-Authors: Nevers QuentinAbstract:Over the past decades, an increasing number of viruses has emerged or re-emerged in humans. Unfortunately, currently approved antiviral drugs target a small set of viruses. Thus, there is an urgent need for the development of broad-spectrum antiviral drugs.Cyclophilins are cellular proteins involved in a large number of biological processes, and in different viral lifecycles from unrelated families. They appear as a potential target for the development of broad-spectrum antiviral approaches. However, currently available cyclophilin inhibitors have drawbacks which limit their clinical use.By means of "fragment-based drug design", we generated a new class of small-molecule cyclophilin inhibitors (SMCypI), unrelated with those already available. Cristallographic studies revealed that the SMCypIs bind to two close pockets of the active site and inhibit cyclophilin PPIase activity. These compounds do not bear immunosuppressive properties and inhibit the replication of HIV, HCV and coronaviruses in vitro.We characterized the anti-HCV activity of C31, the most potent inhibitor of cyclophilin PPIase activity. C31 had pan-genotypic HCV inhibitor properties, with a high barrier to resistance and additive effects with currently approved anti-HCV agents. C31 blocked HCV replication by disrupting the interaction between the nonstructural viral protein NS5A and cyclophilin A in a PPIase-dependent manner. Finally, C31 was active on zika, yellow fever, dengue and West-Nile virus infections.The antiviral activity of the SMCypIs has then been characterized on HCoV-229E infection. Interestingly, PPIase inhibition was necessary, but not sufficient for antiviral effect. A structure-activity relationship study identified a key moiety in the SMCypIs at the interface between the two cyclophilin pockets. F836 has been identified as the most potent compound which inhibited both the cytopathic effect and the intracellular RNA of HCoV-229E without associated cytotoxicity and as potently as alisporivir. This compound targeted HCoV-229E entry at a post-attachment step and was also active on HCoV-OC43 and MERS-CoV strains. We then demonstrated that cyclophilin A was associated with viral particles. By means of CRISPR-Cas9, cell lines depleted for cyclophilin A were generated. Cyclophilin A was identified as a proviral factor for HCoV-229E and was partially involved in F836 antiviral effect. Cyclophilin A expression level was drastically decreased by infection.SMCypIs represent a unique tool to decipher the cellular and molecular mechanisms by which Cyclophilins interfere with viral lifecycles, as well as drugable compounds that could find an indication as broad-spectrum antiviral drugs.Les dernières décennies ont été marquées par l’émergence ou la réémergence d’un nombre croissant de virus pathogènes. Malheureusement, les antiviraux actuellement sur le marché ciblent un nombre restreint de virus ; il y a donc un besoin urgent de développer des antiviraux à large spectre. Les cyclophilines sont des protéines cellulaires impliquées dans un grand nombre de processus biologiques, qui possèdent une activité enzymatique peptidyl-prolyl cis-trans isomérase (PPIase). Elles sont également impliquées dans la réplication de virus appartenant à des familles éloignées et constituent donc une cible de choix pour le développement d'antiviraux à large spectre. Toutefois, les inhibiteurs de cyclophilines disponibles possèdent de nombreux inconvénients qui rendent leur utilisation clinique difficile.Par une stratégie de "fragment-based drug design", nous avons généré une nouvelle famille d'inhibiteurs de cyclophilines, les SMCypI ("Small-Molecule Cyclophilin Inhibitors"), complètement différents de tous les inhibiteurs de cyclophilines existants. La cristallographie de ces composés a montré qu'ils se fixaient dans les deux poches voisines du site actif des cyclophilines et qu'ils inhibaient leur activité PPIase. Ces composés n’étaient pas immunosuppressifs et bloquaient in vitro l'infection par le VIH, le VHC et les Coronavirus.L'activité anti-VHC du C31, composé le plus actif sur l'activité PPIase des cyclophilines, a été caractérisée. Le C31 était un inhibiteur pan-génotypique du VHC, doté d’une haute barrière contre la résistance et présentant une activité additive avec les inhibiteurs du VHC approuvés. Nous avons montré que le C31 bloquait l'infection par le VHC en rompant l'interaction entre la protéine virale NS5A et la cyclophiline A de façon PPIase-dépendante. Enfin, le C31 était actif sur la réplication des virus zika, de la dengue, de la fièvre jaune et du Nil Occidental.L'activité des SMCypI a été caractérisée sur l'infection par le Coronavirus 229E. De manière intéressante, l’inhibition de l’activité PPIase était nécessaire, mais pas suffisante pour l’activité antivirale. Une étude de la relation structure-activité des composés a révélé qu'un groupement chimique situé à l'interface entre les deux poches du site actif des cyclophilines jouait un rôle clé dans l'effet anti-coronavirus. Le F836 a été identifié comme le composé le plus actif, qui bloquait l'effet cytopathique et la quantité d'ARN du HCoV-229E avec la même efficacité que l'alisporivir, sans toxicité associée. Ce composé bloquait l'entrée du HCoV-229E après l'attachement du virus à la surface cellulaire, et était également actif sur l'entrée des HCoV-OC43 et du MERS-CoV. Nous avons par la suite démontré l’association de la cyclophiline A avec les particules virales. Par l'utilisation de la technologie CRISPR-Cas9, des cellules invalidées pour la cyclophiline A ont été générées. La cyclophiline A apparaissait nécessaire pour l'infection par HCoV-229E et la cible de l'effet antiviral du F836.Les SMCypI constituent un outil pour la compréhension des mécanismes par lesquels les cyclophilines modulent les infections virales et représentent des candidats crédibles pour le développement futur d'antiviraux à large spectre
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Development of a new family of cyclophilin inhibitors with broad antiviral spectrum and study of their mechanisms of action in Hepatitis C Virus and Coronavirus infections.
2018Co-Authors: Nevers QuentinAbstract:Les dernières décennies ont été marquées par l’émergence ou la réémergence d’un nombre croissant de virus pathogènes. Malheureusement, les antiviraux actuellement sur le marché ciblent un nombre restreint de virus ; il y a donc un besoin urgent de développer des antiviraux à large spectre. Les cyclophilines sont des protéines cellulaires impliquées dans un grand nombre de processus biologiques, qui possèdent une activité enzymatique peptidyl-prolyl cis-trans isomérase (PPIase). Elles sont également impliquées dans la réplication de virus appartenant à des familles éloignées et constituent donc une cible de choix pour le développement d'antiviraux à large spectre. Toutefois, les inhibiteurs de cyclophilines disponibles possèdent de nombreux inconvénients qui rendent leur utilisation clinique difficile.Par une stratégie de "fragment-based drug design", nous avons généré une nouvelle famille d'inhibiteurs de cyclophilines, les SMCypI ("Small-Molecule Cyclophilin Inhibitors"), complètement différents de tous les inhibiteurs de cyclophilines existants. La cristallographie de ces composés a montré qu'ils se fixaient dans les deux poches voisines du site actif des cyclophilines et qu'ils inhibaient leur activité PPIase. Ces composés n’étaient pas immunosuppressifs et bloquaient in vitro l'infection par le VIH, le VHC et les Coronavirus.L'activité anti-VHC du C31, composé le plus actif sur l'activité PPIase des cyclophilines, a été caractérisée. Le C31 était un inhibiteur pan-génotypique du VHC, doté d’une haute barrière contre la résistance et présentant une activité additive avec les inhibiteurs du VHC approuvés. Nous avons montré que le C31 bloquait l'infection par le VHC en rompant l'interaction entre la protéine virale NS5A et la cyclophiline A de façon PPIase-dépendante. Enfin, le C31 était actif sur la réplication des virus zika, de la dengue, de la fièvre jaune et du Nil Occidental.L'activité des SMCypI a été caractérisée sur l'infection par le Coronavirus 229E. De manière intéressante, l’inhibition de l’activité PPIase était nécessaire, mais pas suffisante pour l’activité antivirale. Une étude de la relation structure-activité des composés a révélé qu'un groupement chimique situé à l'interface entre les deux poches du site actif des cyclophilines jouait un rôle clé dans l'effet anti-coronavirus. Le F836 a été identifié comme le composé le plus actif, qui bloquait l'effet cytopathique et la quantité d'ARN du HCoV-229E avec la même efficacité que l'alisporivir, sans toxicité associée. Ce composé bloquait l'entrée du HCoV-229E après l'attachement du virus à la surface cellulaire, et était également actif sur l'entrée des HCoV-OC43 et du MERS-CoV. Nous avons par la suite démontré l’association de la cyclophiline A avec les particules virales. Par l'utilisation de la technologie CRISPR-Cas9, des cellules invalidées pour la cyclophiline A ont été générées. La cyclophiline A apparaissait nécessaire pour l'infection par HCoV-229E et la cible de l'effet antiviral du F836.Les SMCypI constituent un outil pour la compréhension des mécanismes par lesquels les cyclophilines modulent les infections virales et représentent des candidats crédibles pour le développement futur d'antiviraux à large spectre.Over the past decades, an increasing number of viruses has emerged or re-emerged in humans. Unfortunately, currently approved antiviral drugs target a small set of viruses. Thus, there is an urgent need for the development of broad-spectrum antiviral drugs.Cyclophilins are cellular proteins involved in a large number of biological processes, and in different viral lifecycles from unrelated families. They appear as a potential target for the development of broad-spectrum antiviral approaches. However, currently available cyclophilin inhibitors have drawbacks which limit their clinical use.By means of "fragment-based drug design", we generated a new class of small-molecule cyclophilin inhibitors (SMCypI), unrelated with those already available. Cristallographic studies revealed that the SMCypIs bind to two close pockets of the active site and inhibit cyclophilin PPIase activity. These compounds do not bear immunosuppressive properties and inhibit the replication of HIV, HCV and coronaviruses in vitro.We characterized the anti-HCV activity of C31, the most potent inhibitor of cyclophilin PPIase activity. C31 had pan-genotypic HCV inhibitor properties, with a high barrier to resistance and additive effects with currently approved anti-HCV agents. C31 blocked HCV replication by disrupting the interaction between the nonstructural viral protein NS5A and cyclophilin A in a PPIase-dependent manner. Finally, C31 was active on zika, yellow fever, dengue and West-Nile virus infections.The antiviral activity of the SMCypIs has then been characterized on HCoV-229E infection. Interestingly, PPIase inhibition was necessary, but not sufficient for antiviral effect. A structure-activity relationship study identified a key moiety in the SMCypIs at the interface between the two cyclophilin pockets. F836 has been identified as the most potent compound which inhibited both the cytopathic effect and the intracellular RNA of HCoV-229E without associated cytotoxicity and as potently as alisporivir. This compound targeted HCoV-229E entry at a post-attachment step and was also active on HCoV-OC43 and MERS-CoV strains. We then demonstrated that cyclophilin A was associated with viral particles. By means of CRISPR-Cas9, cell lines depleted for cyclophilin A were generated. Cyclophilin A was identified as a proviral factor for HCoV-229E and was partially involved in F836 antiviral effect. Cyclophilin A expression level was drastically decreased by infection.SMCypIs represent a unique tool to decipher the cellular and molecular mechanisms by which Cyclophilins interfere with viral lifecycles, as well as drugable compounds that could find an indication as broad-spectrum antiviral drugs
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Characterization of the Anti-Hepatitis C Virus Activity of New Nonpeptidic Small-Molecule Cyclophilin Inhibitors with the Potential for Broad Anti- Flaviviridae Activity
'American Society for Microbiology', 2018Co-Authors: Nevers Quentin, Ruiz Isaac, Ahnou Nazim, Donati Flora, Brillet Rozenn, Softic Laurent, Chazal Maxime, Jouvenet Nolwenn, Fourati Slim, Baudesson CamilleAbstract:International audienceAlthough members of the Flaviviridae display high incidence, morbidity, and mortality rates, the development of specific antiviral drugs for each virus is unlikely. Cyclophilins, a family of host peptidyl-prolyl cis-trans isomerases (PPIases), play a pivotal role in the life cycles of many viruses and therefore represent an attractive target for broad-spectrum antiviral development. We report here the pangenotypic anti-hepatitis C virus (HCV) activity of a small-molecule cyclophilin inhibitor (SMCypI). Mechanistic and modeling studies revealed that the SMCypI bound to cyclophilin A in competition with cyclosporine (CsA), inhibited its PPIase activity, and disrupted the CypA-nonstructural protein 5A (NS5A) interaction. Resistance selection showed that the lead SMCypI hardly selected amino acid substitutions conferring low-level or no resistance in vitro. Interestingly, the SMCypI selected D320E and Y321H substitutions, located in domain II of the NS5A protein. These substitutions were previously associated with low-level resistance to cyclophilin inhibitors such as alisporivir. Finally, the SMCypI inhibited the replication of other members of the Flaviviridae family with higher 50% effective concentrations (EC50s) than for HCV. Thus, because of its chemical plasticity and simplicity of synthesis, our new family of SMCypIs represents a promising new class of drugs with the potential for broad-spectrum anti-Flaviviridae activity as well as an invaluable tool to explore the role of Cyclophilins in viral life cycles
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Fragment-based discovery of a new family of non-peptidic small-molecule cyclophilin inhibitors with potent antiviral activities
'Springer Science and Business Media LLC', 2016Co-Authors: Ahmed-belkacem Abdelhakim, Nevers Quentin, Ahnou Nazim, Brillet Rozenn, Colliandre Lionel, Gelin Muriel, Bessin Yannick, Cala Olivier, Douguet Dominique, Bourguet WilliamAbstract:International audienceCyclophilins are peptidyl-prolyl cis/trans isomerases (PPIase) that catalyse the interconversion of the peptide bond at proline residues. Several Cyclophilins play a pivotal role in the life cycle of a number of viruses. The existing cyclophilin inhibitors, all derived from cyclosporine A or sanglifehrin A, have disadvantages, including their size, potential for side effects unrelated to cyclophilin inhibition and drug–drug interactions, unclear antiviral spectrum and manufacturing issues. Here we use a fragment-based drug discovery approach using nucleic magnetic resonance, X-ray crystallography and structure-based compound optimization to generate a new family of non-peptidic, small-molecule cyclophilin inhibitors with potent in vitro PPIase inhibitory activity and antiviral activity against hepatitis C virus, human immunodeficiency virus and coronaviruses. This family of compounds has the potential for broad-spectrum, high-barrier-to-resistance treatment of viral infections
Nikolai V. Naoumov - One of the best experts on this subject based on the ideXlab platform.
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alisporivir inhibition of hepatocyte Cyclophilins reduces hbv replication and hepatitis b surface antigen production
Gastroenterology, 2015Co-Authors: Sandra Phillips, S Chokshi, Udayan Chatterji, A Riva, Michael Bobardt, Roger Williams, Philippe Gallay, Nikolai V. NaoumovAbstract:Background & Aims Cyclophilins are host factors required for hepatitis C virus replication. Cyclophilin inhibitors such as alisporivir have shown strong anti–hepatitis C virus activity in vitro and in clinical studies. However, little is known about whether hepatocyte Cyclophilins are involved in the hepatitis B virus (HBV) life cycle. We investigated the effects of 2 cyclophilin inhibitors (alisporivir and NIM811) on HBV replication and hepatitis B surface antigen (HBsAg) production in cell lines. Methods Liver-derived cell lines producing full-length HBV and HBsAg particles, owing to stable (HepG2215) or transient (HuH-7) transfection, or infected with HBV (HepaRG cells; Invitrogen [Carlsbad, CA]), were incubated with alisporivir or NIM811 alone, or alisporivir in combination with a direct antiviral (telbivudine). The roles of individual Cyclophilins in drug response was evaluated by small interfering RNA knockdown of cyclophilin (CYP)A, CYPC, or CYPD in HepG2215 cells, or CYPA knockdown in HuH-7 cells. The kinetics of antiviral activity were assessed based on levels of HBV DNA and HBsAg and Southern blot analysis. Results In HepG2215, HuH-7, and HepaRG cells, alisporivir reduced intracellular and secreted HBV DNA, in a dose-dependent manner. Knockdown of CYPA, CYPC, or CYPD (reduced by 80%) significantly reduced levels of HBV DNA and secreted HBsAg. Knockdown of CYPA significantly reduced secretion of HBsAg, leading to accumulation of intracellular HBsAg; the addition of alisporivir greatly reduced levels of HBsAg in these cells. The combination of alisporivir and telbivudine had greater antiviral effects than those of telbivudine or alisporivir alone. Conclusions Alisporivir inhibition of Cyclophilins in hepatocyte cell lines reduces replication of HBV DNA and HBsAg production and secretion. These effects are potentiated in combination with direct antiviral agents that target HBV-DNA polymerase.
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Cyclophilin inhibition as potential therapy for liver diseases.
Journal of hepatology, 2014Co-Authors: Nikolai V. NaoumovAbstract:The Cyclophilins are a group of proteins with peptidyl-prolyl isomerase enzymatic activity, localised in different cellular compartments and involved in a variety of functions related to cell metabolism and energy homeostasis, having enhanced expression in inflammation or malignancy. Cyclophilin A (CypA), the most abundantly expressed cyclophilin, is present mainly in the cytoplasm and is a host factor involved in the life cycle of multiple viruses. The extracellular fractions of CypA and CypB are potent pro-inflammatory mediators. CypD, located in mitochondria, is a key regulator of mitochondrial permeability transition pores, and is critical for necrotic cell death. Cyclosporines are the prototype cyclophilin inhibitors. Cyclic peptides, which bind and inhibit Cyclophilins without having immunosuppressive properties, have been generated by chemical modifications of cyclosporin A. In addition, cyclophilin inhibitors that are structurally different from cyclosporines have been synthesized. The involvement of Cyclophilins in the pathogenesis of different liver diseases has been established using both in vitro and in vivo investigations, thus indicating that cyclophilin inhibition may be of therapeutic benefit. This review summarises the evidence for potential therapeutic applications of non-immunosuppressive cyclophilin inhibitors, alone or in combination with other agents, in virus-induced liver diseases like hepatitis C, B or Delta, liver inflammation and fibrosis, acetaminophen-induced liver toxicity and hepatocellular carcinoma.
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oc 025 alisporivir inhibition of cellular Cyclophilins disrupts hepatitis b virus hbv replication and this effect is further enhanced in combination with direct antiviral targeting hbv dna polymerase in vitro
Gut, 2012Co-Authors: S Chokshi, A Riva, S Phillips, Nikolai V. NaoumovAbstract:Introduction Cyclophilins are intracellular proteins with enzymatic activity—peptidyl-prolyl-isomerase that plays a major role in the life cycle of Hepatitis C virus. By targeting host Cyclophilins Alisporivir (DEB025) exerts potent anti-HCV activity in vitro and in clinical studies. We have recently shown in vitro that cyclophilin inhibition with Alisporivir or NIM811 also interferes with HBV replication, with Alisporivir having a greater effect than NIM811. To elucidate the underlying mechanisms, in the present study we compared in vitro the effects on HBV replication of Alisporivir alone, Alisporivir in combination with a potent antiviral targeting HBV-DNA polymerase, and in cells after selective knockdown of individual Cyclophilins. Methods Stably (HepG2215) and transiently (HUH-7) transfected cells, producing full HBV virions and HBsAg particles, were treated with different Alisporivir concentrations (0.25/1.0/5.0/20 ug/ml) alone, Telbivudine alone, or combinations of Alisporivir and Telbivudine. To determine the involvement of individual Cyclophilins, HepG2215 cells were transfected with siRNA-specific for cyclophilin (Cyp) A, C or D and additionally treated with Alisporivir. Cytoplasmic extracts and supernatants were harvested at baseline; 24, 48 and 72 h post-treatment. The kinetics of antiviral activity was assessed by quantitation of intracellular and secreted HBV-DNA (real-time qPCR) and HBsAg levels (ELISA). Results Alisporivir treatment resulted in dose-dependent reduction of intracellular and secreted HBV-DNA from HepG2215 and HUH-7 cells at all time points, by 70% (p=0.004) and 63% (p 3-fold reduction of HBsAg vs either Alisporivir or Telbivudine alone. CypA, C or D expression was markedly reduced after transfection with corresponding siRNA, which was associated with significant decrease of HBV-DNA and HBsAg levels (p Conclusion These results suggest that Alisporivir interferes with multiple sites of HBV replication and has synergistic antiviral activity with direct antiviral targeting viral DNA polymerase, such as Telbivudine. Competing interests None declared.
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p43 cellular protein cyclophilin a is involved in hepatitis b virus replication and its inhibition with deb025 alisporivir or nim811 demonstrates antiviral activity in vitro
Gut, 2011Co-Authors: S Chokshi, A Riva, S Phillips, Nikolai V. NaoumovAbstract:Introduction Cyclophilins are ubiquitously expressed intracellular proteins that have enzymatic activity—peptidyl-prolyl cis-trans isomerase, and are involved in regulation of mitochondrial/cytosolic transport in the cells. DEB025 (Alisporivir) and NIM811 are non-immunosuppressive cyclophilin inhibitors that efficiently block hepatitis C virus replication by targeting host rather than viral proteins, however the potential impact of cyclophillin inhibition on hepatitis B virus (HBV) life cycle is poorly understood. Aim In the present study we employed a panel of liver cell lines to investigate the ability of cyclophilin inhibitors DEB025 (Alisporivir) and NIM811 to affect HBV replication and viral particle secretion from the cells. Method HepG2215 cells, stably transfected with the full HBV genome and supporting the production of both infectious virions and HBsAg particles, and the parent cells (HepG2) were cultured for 7 days (baseline), prior to treatment with DEB025 or NIM811 at 0.25; 1.0 and 5.0 mg/ml. The cells and supernatants were harvested separately at baseline; 6, 24, 48 and 72 h after addition of cyclophilin inhibitors. HBV DNA levels - both intracellular and in culture supernatants—were quantitated by Taqman qPCR (ABI7500). Western blot and ELISA were used to assess intracellular and secreted HBsAg, respectively. PLC/PRF/5 cells, expressing only HBsAg, were also tested. Cyclophilin expression in the cells was silenced by transfection separately with siRNA for Cyclophilins A, B, C or D to determine the role of individual Cyclophilins in HBV replication. Results Cyclophilin inhibition with either DEB025 or NIM811 significantly reduced cytoplasmic core-particle associated HBV DNA levels in the cells, between 2 and 10-fold as compared with the control cells. The most pronounced reduction of intracellular HBV DNA (by 10-fold at 72 h) was observed with DEB025 5 mg/ml, which was greater than the reduction observed with NIM811. Similarly, DEB025 (at 1 and 5 mg/ml) showed a greater impact in reducing HBV virion secretion in the supernatants, compared with NIM811. HBsAg secretion from the cells was also reduced by up to 50% when compared to controls. Cyclophilin-A expression was markedly reduced after transfection with corresponding siRNA, which led to a rapid decrease of intracellular HBV DNA by 2 logs. HBV-DNA was reduced further when the cyclophillin-A silenced cultures were treated with NIM811 or DEB025. Conclusion These results demonstrate that cyclophilin A is directly involved in HBV replication. Cyclophilin inhibition by DEB025 or NIM811 interferes with HBV replication within liver cells and reduces the secretion of infectious virions and HBsAg particles from the cells, with DEB025 having a greater antiviral activity than NIM811.
Joseph Heitman - One of the best experts on this subject based on the ideXlab platform.
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The Cyclophilins.
Genome biology, 2005Co-Authors: Ping Wang, Joseph HeitmanAbstract:Cyclophilins (Enzyme Commission (EC) number 5.1.2.8) belong to a group of proteins that have peptidyl-prolyl cis-trans isomerase activity; such proteins are collectively known as immunophilins and also include the FK-506-binding proteins and the parvulins. Cyclophilins are found in all cells of all organisms studied, in both prokaryotes and eukaryotes; humans have a total of 16 cyclophilin proteins, Arabidopsis up to 29 and Saccharomyces 8. The first member of the Cyclophilins to be identified in mammals, cyclophilin A, is the major cellular target for, and thus mediates the actions of, the immunosuppressive drug cyclosporin A. Cyclophilin A forms a ternary complex with cyclosporin A and the calcium-calmodulin-activated serine/threonine-specific protein phosphatase calcineurin; formation of this complex prevents calcineurin from regulating cytokine gene transcription. Recent studies have implicated a diverse array of additional cellular functions for Cyclophilins, including roles as chaperones and in cell signaling.
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Cyclophilin A and Ess1 interact with and regulate silencing by the Sin3-Rpd3 histone deacetylase.
The EMBO journal, 2000Co-Authors: Miguel Arévalo-rodríguez, Maria E Cardenas, Steven D. Hanes, Joseph HeitmanAbstract:Three families of prolyl isomerases have been identified: Cyclophilins, FK506-binding proteins (FKBPs) and parvulins. All 12 Cyclophilins and FKBPs are dispensable for growth in yeast, whereas the one parvulin homolog, Ess1, is essential. We report here that cyclophilin A becomes essential when Ess1 function is compromised. We also show that overexpression of cyclophilin A suppresses ess1 conditional and null mutations, and that cyclophilin A enzymatic activity is required for suppression. These results indicate that cyclophilin A and Ess1 function in parallel pathways and act on common targets by a mechanism that requires prolyl isomerization. Using genetic and biochemical approaches, we found that one of these targets is the Sin3-Rpd3 histone deacetylase complex, and that cyclophilin A increases and Ess1 decreases disruption of gene silencing by this complex. We show that conditions that favor acetylation over deacetylation suppress ess1 mutations. Our findings support a model in which Ess1 and cyclophilin A modulate the activity of the Sin3-Rpd3 complex, and excess histone deacetylation causes mitotic arrest in ess1 mutants.
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all Cyclophilins and fk506 binding proteins are individually and collectively dispensable for viability in saccharomyces cerevisiae
Proceedings of the National Academy of Sciences of the United States of America, 1997Co-Authors: Kara Dolinski, Scott Muir, Maria E Cardenas, Joseph HeitmanAbstract:The Cyclophilins and FK506 binding proteins (FKBPs) bind to cyclosporin A, FK506, and rapamycin and mediate their immunosuppressive and toxic effects, but the physiological functions of these proteins are largely unknown. Cyclophilins and FKBPs are ubiquitous and highly conserved enzymes that catalyze peptidyl-prolyl isomerization, a rate-limiting step during in vitro protein folding. We have addressed their functions by a genetic approach in the yeast Saccharomyces cerevisiae. Five Cyclophilins and three FKBPs previously were identified in yeast. We identified four additional enzymes: Cpr6 and Cpr7, which are homologs of mammalian cyclophilin 40 that have also recently been independently isolated by others, Cpr8, a homolog of the secretory pathway cyclophilin Cpr4, and Fpr4, a homolog of the nucleolar FKBP, Fpr3. None of the eight Cyclophilins or four FKBPs were essential. Surprisingly, yeast mutants lacking all 12 immunophilins were viable, and the phenotype of the dodecuplet mutant resulted from simple addition of the subtle phenotypes of each individual mutation. We conclude that Cyclophilins and FKBPs do not play an essential general role in protein folding and find little evidence of functional overlap between the different enzymes. We propose that each cyclophilin and FKBP instead regulates a restricted number of unique partner proteins that remain to be identified.
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A yeast cyclophilin gene essential for lactate metabolism at high temperature.
Proceedings of the National Academy of Sciences of the United States of America, 1992Co-Authors: Edward S. Davis, Joseph Heitman, Andrea Becker, Michael N. Hall, Miles B. BrennanAbstract:The Cyclophilins are a family of ubiquitous eukaryotic proteins first identified by high affinity for cyclosporin A (CsA). The immunosuppressant and cytotoxic effects of CsA are thought to result from formation of a toxic complex between cyclophilin and CsA rather than from inhibition of cyclophilin function. The physiological role(s) of the Cyclophilins is unknown. Cyclophilins have in vitro peptidylprolyl cistrans isomerase (PPIase) activity, and thus may be involved in protein folding in vivo. We have isolated a yeast cyclophilin gene, CPR3, which encodes a presumptive mitochondrial isoform. While CPR3 disruption mutants lack any phenotype at 30 degrees C, they are unable to grow on L-lactate at 37 degrees C. Disruptions of two other cyclophilin genes (CPR1, CPR2) and of FPR1, the gene encoding an FK506 binding protein with PPIase activity, do not affect growth on L-lactate at 37 degrees C. L-Lactate metabolism requires transcriptional induction of CYB2, the gene encoding flavocytochrome b2; cpr3 mutants induce transcription of this gene normally. This result demonstrates a conditional lethal phenotype for a cyclophilin mutation and presents a system for genetic and biochemical analysis of cyclophilin function.
Nazim Ahnou - One of the best experts on this subject based on the ideXlab platform.
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Characterization of the Anti-Hepatitis C Virus Activity of New Nonpeptidic Small-Molecule Cyclophilin Inhibitors with the Potential for Broad Anti- Flaviviridae Activity
Antimicrobial Agents and Chemotherapy, 2018Co-Authors: Quentin Nevers, Nazim Ahnou, Rozenn Brillet, Isaac Ruiz, Flora Donati, Laurent Softic, Maxime Chazal, Nolwenn Jouvenet, Slim Fourati, Camille BaudessonAbstract:Although members of the Flaviviridae display high incidence, morbidity, and mortality rates, the development of specific antiviral drugs for each virus is unlikely. Cyclophilins, a family of host peptidyl-prolyl cis-trans isomerases (PPIases), play a pivotal role in the life cycles of many viruses and therefore represent an attractive target for broad-spectrum antiviral development. We report here the pangenotypic anti-hepatitis C virus (HCV) activity of a small-molecule cyclophilin inhibitor (SMCypI). Mechanistic and modeling studies revealed that the SMCypI bound to cyclophilin A in competition with cyclosporine (CsA), inhibited its PPIase activity, and disrupted the CypA-nonstructural protein 5A (NS5A) interaction. Resistance selection showed that the lead SMCypI hardly selected amino acid substitutions conferring low-level or no resistance in vitro. Interestingly, the SMCypI selected D320E and Y321H substitutions, located in domain II of the NS5A protein. These substitutions were previously associated with low-level resistance to cyclophilin inhibitors such as alisporivir. Finally, the SMCypI inhibited the replication of other members of the Flaviviridae family with higher 50% effective concentrations (EC50s) than for HCV. Thus, because of its chemical plasticity and simplicity of synthesis, our new family of SMCypIs represents a promising new class of drugs with the potential for broad-spectrum anti-Flaviviridae activity as well as an invaluable tool to explore the role of Cyclophilins in viral life cycles.
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Fragment-based discovery of a new family of non-peptidic small-molecule cyclophilin inhibitors with potent antiviral activities
Nature Communications, 2016Co-Authors: Abdelhakim Ahmed-belkacem, Quentin Nevers, Lionel Colliandre, Nazim Ahnou, Muriel Gelin, Yannick Bessin, Rozenn Brillet, Olivier Cala, Dominique Douguet, William BourguetAbstract:Cyclophilins are peptidyl-prolyl cis/trans isomerases (PPIase) that catalyse the interconversion of the peptide bond at proline residues. Several Cyclophilins play a pivotal role in the life cycle of a number of viruses. The existing cyclophilin inhibitors, all derived from cyclosporine A or sanglifehrin A, have disadvantages, including their size, potential for side effects unrelated to cyclophilin inhibition and drug–drug interactions, unclear antiviral spectrum and manufacturing issues. Here we use a fragment-based drug discovery approach using nucleic magnetic resonance, X-ray crystallography and structure-based compound optimization to generate a new family of non-peptidic, small-molecule cyclophilin inhibitors with potent in vitro PPIase inhibitory activity and antiviral activity against hepatitis C virus, human immunodeficiency virus and coronaviruses. This family of compounds has the potential for broad-spectrum, high-barrier-to-resistance treatment of viral infections.
