Abstract 15086: Caveolin-1 Dependent APPL1 Nuclear Translocation as a Novel Mechanism Mediating Adiponectin Endothelial Protection in Diabetes
Introduction: Adiponectin (APN) regulates multiple genes and exerts pleiotropic vascular protective effects. However, intracellular signaling mediating APN gene regulatory effect and vasculoprotective actions remain unclear.
Objective: To identify unrecognized APN signaling pathways that plays important role in APN vascular protection.
Methods and Results: High glucose/high lipid (HG/HL) cultured RAEC were utilized for in vitro molecular investigation and high-fat induced diabetic mice were utilized for in vivo concept-proving study. APN treatment reduced HG/HL-induced endothelial injury in a Cav1- and APPL1-dependent manner. Co-immunoprecipitation demonstrated that APN promotes Cav1-APPL1 interaction and signaling complex formation. Most interestingly, confocal microscope and Western analysis demonstrated that APN treatment caused significant APPL1 nuclear translocation. This process was abolished in Cav1 knockdown cells, indicating that Cav1 functions as a vehicle for APN-induced APPL1 nuclear translocation. Of the 32 APN-upregulated genes identified by Endothelial Cell Biology RT2 Profiler PCR Array, 28 were upregulated in a Cav1/APPL1-dependent manner. Pathway analysis demonstrated that majority of Cav1/APPL1-dependent upregulated genes are involved in cell growth and survival, and 10 of them are anti-apoptotic/pro-antigenic double function genes. Among these 10 anti-apoptotic/pro-antigenic double function genes, expression level (gene and protein) of Angiopoietin-1, VEGFR1 and Occludin were significantly reduced in aortic EC isolated from diabetic mice or exposed to high glucose/high lipid (HG/HL). In vivo APN treatment improved Angiopoietin-1/VEGFR1/Occludin expression in diabetic endothelial cells. Finally, APN treatment significantly attenuated HG/HL-induced apoptosis, reduced permeability, and promoted tube formation in cultured EC. These effects were lost in APPL1 or Cav1 single knockdown or Angiopoietin-1/VEGFR1/Occludin triple-knockdown cells.
Conclusion: Taken together, the current study demonstrated for the first time that APN induced Cav1-dependent APPL1 nuclear translocation is a novel mechanism mediating APN mediated gene expression and endothelial protection in diabetes.
Author Disclosures: Y. Du: None. Y. Wang: None. W. Lau: None. T.A. Christopher: None. B. Lopez: None. X. Ma: None.
- © 2016 by American Heart Association, Inc.