Abstract 15377: Investigating the Role of Breast Cancer Susceptibility Gene 2 in High Glucose-Induced Endothelial Dysfunction

Abstract

Introduction and Hypothesis: Mutations in the breast cancer susceptibility gene 2 (BRCA2) impair DNA damage repair which can eventually culminate in cancer, inflammation and/or apoptosis. Hyperglycemia-induced oxidative stress triggers DNA damage, inflammation and apoptosis, which are common contributors to endothelial dysfunction in diabetes. Here, we assessed the hypothesis that BRCA2 plays critical role in hyperglycemia-induced endothelial dysfunction. Methods and Results: Human umbilical vein endothelial cells (HUVECs) were exposed to high- (HG; 25 mM) or normal glucose (NG; 5 mM) and BRCA2 expression was measured. Our data showed significant BRCA2 upregulation in HG-treated HUVECs. Next, we successfully silenced BRCA2 in HUVECs, and measured the expression levels of p53 and p21 in HG- and NG-treated BRCA2-silenced HUVECs. We observed a significant upregulation of p53 and p21 in BRCA2-deficient HUVECs, which was further augmented by HG. Next, we measured the migratory and angiogenic potential of control and BRCA2-seilenced HUVECs under NG and HG. Our preliminary data showed that HG and loss of BRCA2 together inhibited the migratory capacity and angiogenic potential of HUVECs. To understand the mechanism behind the effect of HG on BRCA2-deficient ECs, we measured expression levels of endothelial nitric oxide synthase (eNOS). Both expression and activation of eNOS was reduced in HG-treated BRCA2-deficient HUVECs. To understand the effect of loss of BRCA2 on overall endothelial transcriptome and to understand mechanisms, we performed RNA sequencing on scrambled control- and siBRCA2-transfected HUVECs. Interestingly, a total of 3150 genes were differentially expressed in BRCA2-deficient HUVECs compared to the control group. Conclusion: Collectively, these findings reveal a novel role for BRCA2 as a regulator of endothelial function in context of HG treatment in vitro . Our RNA sequencing data shows theimportance of BRCA2 in regulating endothelial transcriptome and overall endothelial function. Further studies are underway; however, these results may provide important implications concerning the susceptibility of BRCA2 mutation carriers to HG-induced endothelial dysfunction as well as other CVDs.