title: Cyclophilin-mediated pathways in the effect of cyclosporin A on endothelial cells: role of vascular endothelial growth factor.
abstract: The relative importance of cyclophilin (CyP) versus calcineurin (Cn)-mediated mechanisms in the effect of cyclosporin A (CsA) on endothelial cells (ECs) is largely unknown. In cultured ECs, CsA was cytotoxic/proapoptotic or cytoprotective/antiapoptotic at high or low concentrations, respectively. CsA analogs (MeVal-4-CsA and MeIle-4-CsA), which bind to CyP but do not inhibit Cn, closely reproduced the CsA effects. Based on our previous data, the role of vascular endothelial growth factor (VEGF) as a mediator of CsA-induced cytoprotection was further analyzed. The actions of CsA and CsA analogs were shifted from a protective to a cell-damaging pattern in the presence of a specific anti-VEGF monoclonal antibody (mAb). This positive interaction was further supported by a transient increase in cytosolic free calcium concentration ([Ca(2+)](i)) by VEGF after pretreatment with either CsA or MeVal-4-CsA and an increase in the expression and synthesis of VEGF receptor 2 (VEGFR2). Of functional importance, blockade of the interaction between VEGF and VEGFR2 by a VEGFR2 mAb abolished the cytoprotective effect of CsA. In addition, preconditioning with low concentrations of CsA or CsA analogs increased both cytoprotection and VEGFR2 mRNA expression when EC were exposed to higher concentrations of CsA. In summary, our results reveal that (1) the biphasic responses to CsA in EC are related to the interaction of CsA with CyP rather than with Cn and (2) VEGF is a critical factor in the cytoprotective effect of CsA, by a mechanism that involves VEGFR2.
authors.affiliation: Laboratorio de Nefrología-Hipertensión, Fundación Jiménez Díaz, Universidad Autónoma, Instituto Reina Sofía de Investigación Nefrológica, Madrid, Spain.
authors.forename: M Victoria
authors.initials: MV
authors.lastname: Alvarez-Arroyo
authors.forename: Susana
authors.initials: S
authors.lastname: Yagüe
authors.forename: Ronald M
authors.initials: RM
authors.lastname: Wenger
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Pereira
authors.forename: Sonsoles
authors.initials: S
authors.lastname: Jiménez
authors.forename: Francisco R
authors.initials: FR
authors.lastname: González-Pacheco
authors.forename: M Angeles
authors.initials: MA
authors.lastname: Castilla
authors.forename: Juan José P
authors.initials: JJ
authors.lastname: Deudero
authors.forename: Carlos
authors.initials: C
authors.lastname: Caramelo
mesh_terms: D000818:Animals; D019703:Calcineurin / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D002478:Cells, Cultured; D021983:Cyclophilins / Q000502:physiology*; D016572:Cyclosporine / Q000494:pharmacology* / Q000633:toxicity; D019610:Cytoprotection; D004268:DNA-Binding Proteins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D016228:Endothelial Growth Factors / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism; D007700:Kinetics; D008222:Lymphokines / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D012333:RNA, Messenger / Q000096:biosynthesis; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000502:physiology; D017978:Receptors, Growth Factor / Q000235:genetics / Q000502:physiology; D040262:Receptors, Vascular Endothelial Growth Factor; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
chemical_list: D004268:DNA-Binding Proteins; D016228:Endothelial Growth Factors; D008222:Lymphokines; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D012333:RNA, Messenger; D017978:Receptors, Growth Factor; D014157:Transcription Factors; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D016572:Cyclosporine; D020794:Receptor Protein-Tyrosine Kinases; D040262:Receptors, Vascular Endothelial Growth Factor; D019703:Calcineurin; D021983:Cyclophilins; D002118:Calcium