Discipline: Biological Sciences
Room: Exhibit Hall A
Wendy Camejo Nunez - Morgan State University
Co-Author(s): Catherine Demos, Georgia Tech and Emory University, Atlanta, GA; Nicole Noren Hooten, National Institute on Aging, NIH, Baltimore, MD; Sandeep Kumar, Georgia Tech and Emory University, Atlanta, GA; Hanjoong Jo, Georgia Tech and Emory University, Atlanta, GA; Michelle K. Evans, National Institute on Aging, NIH, Baltimore, MD; Douglas F. Dluzen, Morgan State University, Baltimore, MD
Hypertension is a major risk factor for cardiovascular and cerebrovascular diseases, including atherosclerosis. Over 85 million people in the United States live with hypertension, and African Americans (AAs) have the highest prevalence. Nearly 50% of AA women will be diagnosed with hypertension; however, few studies focus on this population and examine how hypertension develops and leads to downstream complications like atherosclerosis. Differential gene expression (DGE) is considered an important contributing factor to the predisposition and pathology of many diseases, including hypertension and atherosclerosis. The goal of this study is to identify DGE across multiple models of hypertension and functionally-validate the most relevant differentially-expressed genes. Here, we performed a meta-analysis of microarrays examining patterns of DGE in peripheral blood mononuclear cells (PBMCs) isolated from AA and white women with hypertension (n=6/group) and within the carotid artery of mice exposed to disturbed blood flow through partial carotid ligation (PCL) (n=5/group). We used the cut-off values of P<0.05, an absolute value in fold-change ≥1.5-fold, and an FDR or 0.3 to identify significant genes. We found that PPP1R16B, GADD45A, ADAM15, ICAM15, SNN, BIRC3, FBXO34, ICK, STX6, HMGB2, CALML4, SIVA1, and EHBP1L1 overlapped between these hypertension datasets. We also identified an overlap of 4 miRNAs: miR-19b-1-5p, miR-103a-2-5p, miR-20a-5p, and miR-30c-5p. We hypothesized that disturbed blood flow differentially regulates the expression of several or all of these genes. We exposed human aortic endothelial cells (HAECs) under unidirectional shear stress vs. oscillatory shear stress using a cone-and-plate viscometer for 24 hours. We identified CALML4 to be significantly downregulated (P<0.05; n=3) while STX6 was significantly upregulated (P<0.05; n=3) in oscillatory shear stress vs. unidirectional shear stress control. We observed reciprocal expression of miR-20a-5p and miR-103a-2-5p. An in silico analysis using TargetScan predicted that miR-20a-5p targets STX6 and miR-103a-2-5p targets CALML4. We validated these predictions by overexpressing miR-20a-5p in HAECs, in which the expression of STX6 was significantly downregulated (P<0.05, n=2). Currently, we are validating miR-103a-2-5p as a regulator of CALML4 expression. We are also treating HAECs and HUVECs with Angiotensin II to identify changes in the expression of these genes, as this is an important hormone in hypertension. Future studies are warranted to validate this miRNA-mediated regulation of gene expression and downstream endothelial function. These studies can lead to a better understanding of hypertension and hypertension-related complications like atherosclerosis, particularly in the most at-risk populations.
Funder Acknowledgement(s): This study was supported by the NIA Intramural Research Program, the NIGMS RISE, the NIGMS ASCEND and the NIMHD RCMI at Morgan.
Faculty Advisor: Douglas F. Dluzen, email@example.com
Role: I performed the meta-analysis to identify the overlapping genes between the microarrays. I validated the expression on those genes in HAEC cells under shear stress. I transfected HAEC cells with miR-20a to verify the overexpression of STX6. I performed the in silico analysis of miRNA using TargetScan.