Sirolimus-FKBP12.6 Impairs Endothelial Barrier Function Through Protein Kinase C-alpha Activation and Disruption of the p120-Vascular Endothelial Cadherin Interaction

• Type of Material: Article
• Authors: Anwer Habib, Emory University; Vinit Karmali, Emory University; Rohini Polavarapu, Emory University; Hirokuni Akahori, Emory University; Qi Cheng, CV Path Institute, Inc.; Kim Pachura, Emory University; Frank D. Kolodgie, CV Path Institute, Inc.; Aloke Finn, Emory University
• Language: English
• Date: 2013-10-01
• Publisher: American Heart Association
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2013 American Heart Association, Inc.
• Final Published Version (URL): http://dx.doi.org/10.1161/ATVBAHA.113.301659
• Title of Journal or Parent Work: Arteriosclerosis, Thrombosis, and Vascular Biology
• ISSN: 1079-5642
• Volume: 33
• Issue: 10
• Start Page: 2425
• End Page: 2431
• Grant/Funding Information: This study was supported by the Carlyle Fraser Heart Center, CVPath Inc., American Heart Association and US NIH grant RO1 HL096970-01A.; AVF has sponsored research agreements with Medtronic CardioVascular and Boston Scientific.; AH is supported with an AHA Postdoctoral Fellowship grant (Greater Southeast Affiliate).
• Keywords: PROLIFERATION SIGNAL INHIBITORS; AKT; PKC; HEART-TRANSPLANTATION; Life Sciences & Biomedicine; Cardiovascular System & Cardiology; EXPRESSION; Peripheral Vascular Disease; IN-VITRO; RAPAMYCIN; PHOSPHORYLATION; endothelium; Hematology; Science & Technology; PATHWAYS; RYANODINE RECEPTOR; PERMEABILITY; sirolimus
• Research Categories: Health Sciences, Medicine and Surgery; Health Sciences, General

Abstract

OBJECTIVE - : Sirolimus (SRL) is an immunosuppressant drug used to prevent rejection in organ transplantation and neointimal hyperplasia when delivered from drug-eluting stents. Major side effects of SRL include edema and local collection of intimal lipid deposits at drug-eluting stent sites, suggesting that SRL impairs endothelial barrier function (EBF). The aim of this study was to address the role of SRL on impaired EBF and the potential mechanisms involved. APPROACH AND RESULTS - : Cultured human aortic endothelial cells (HAECs) and intact human and mouse endothelium was examined to determine the effect of SRL, which binds FKBP12.6 to inhibit the mammalian target of rapamycin, on EBF. EBF, measured by transendothelial electrical resistance, was impaired in HAECs when treated with SRL or small interfering RNA for FKBP12.6 and reversed when pretreated with ryanodine, a stabilizer of ryanodine receptor 2 intracellular calcium release channels. Intracellular calcium increased in HAECs treated with SRL and normalized with ryanodine pretreatment. SRL-treated HAECs demonstrated increases in protein kinase C-α phosphorylation, a calcium sensitive serine/threonine kinase important in vascular endothelial (VE) cadherin barrier function through its interaction with p120-catenin (p120). Immunostaining of HAECs, human coronary and mouse aortic endothelium treated with SRL showed disruption of p120-VE cadherin interaction treated with SRL. SRL impairment of HAEC EBF was reduced with protein kinase C-α small interfering RNA. Mice treated with SRL demonstrated increased vascular permeability by Evans blue albumin extravasation in the lungs, heart, and aorta. CONCLUSIONS - : SRL-FKBP12.6 impairs EBF by activation of protein kinase C-α and downstream disruption of the p120-VE cadherin interaction in vascular endothelium. These data suggest this mechanism may be an important contributor of SRL side effects related to impaired EBF.