title: Cyclosporin a disrupts notch signaling and vascular lumen maintenance.
abstract: Cyclosporin A (CSA) suppresses immune function by blocking the cyclophilin A and calcineurin/NFAT signaling pathways. In addition to immunosuppression, CSA has also been shown to have a wide range of effects in the cardiovascular system including disruption of heart valve development, smooth muscle cell proliferation, and angiogenesis inhibition. Circumstantial evidence has suggested that CSA might control Notch signaling which is also a potent regulator of cardiovascular function. Therefore, the goal of this project was to determine if CSA controls Notch and to dissect the molecular mechanism(s) by which CSA impacts cardiovascular homeostasis. We found that CSA blocked JAG1, but not Dll4 mediated Notch1 NICD cleavage in transfected 293T cells and decreased Notch signaling in zebrafish embryos. CSA suppression of Notch was linked to cyclophilin A but not calcineurin/NFAT inhibition since N-MeVal-4-CsA but not FK506 decreased Notch1 NICD cleavage. To examine the effect of CSA on vascular development and function, double transgenic Fli1-GFP/Gata1-RFP zebrafish embryos were treated with CSA and monitored for vasculogenesis, angiogenesis, and overall cardiovascular function. Vascular patterning was not obviously impacted by CSA treatment and contrary to the anti-angiogenic activity ascribed to CSA, angiogenic sprouting of ISV vessels was normal in CSA treated embryos. Most strikingly, CSA treated embryos exhibited a progressive decline in blood flow that was associated with eventual collapse of vascular luminal structures. Vascular collapse in zebrafish embryos was partially rescued by global Notch inhibition with DAPT suggesting that disruption of normal Notch signaling by CSA may be linked to vascular collapse. However, multiple signaling pathways likely cause the vascular collapse phenotype since both cyclophilin A and calcineurin/NFAT were required for normal vascular function. Collectively, these results show that CSA is a novel inhibitor of Notch signaling and vascular function in zebrafish embryos.
authors.affiliation: Department of Cancer and Cell Biology, University of Cincinnati, Cincinnati, Ohio, United States of America.
authors.forename: Raghav
authors.initials: R
authors.lastname: Pandey
authors.affiliation: Department of Biology, Duke University, Durham, North Carolina, United States of America.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Botros
authors.affiliation: Department of Pharmacology and Molecular Sciences, and Medical Scientist Training Program, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America.
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Nacev
authors.affiliation: Department of Biology, Boise State University, Boise, Idaho, United States of America.
authors.forename: Allan R
authors.initials: AR
authors.lastname: Albig
mesh_terms: D000818:Animals; D019703:Calcineurin / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism; D021984:Cyclophilin A / Q000378:metabolism; D016572:Cyclosporine / Q000494:pharmacology*; D004625:Embryo, Nonmammalian / Q000098:blood supply / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D057809:HEK293 Cells; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D000072100:Jagged-1 Protein; D008565:Membrane Proteins / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D051880:Receptors, Notch / Q000378:metabolism*; D000072099:Serrate-Jagged Proteins; D015398:Signal Transduction / Q000187:drug effects*; D015027:Zebrafish / Q000196:embryology*; D029961:Zebrafish Proteins
chemical_list: D002135:Calcium-Binding Proteins; D036341:Intercellular Signaling Peptides and Proteins; C000606273:JAG1 protein, human; D000072100:Jagged-1 Protein; D008565:Membrane Proteins; D051880:Receptors, Notch; D000072099:Serrate-Jagged Proteins; D029961:Zebrafish Proteins; C000606276:jag1a protein, zebrafish; D016572:Cyclosporine; D019703:Calcineurin; D021984:Cyclophilin A