Abstract 690: Circulating Proteomics And Endothelial Cell Phenotype In Patients With Type 2 Diabetes Mellitus (T2DM)

Patients with T2DM display endothelial dysfunction that predicts cardiovascular risk. We have previously demonstrated reduced eNOS activation in endothelial cells (ECs) isolated from patients with T2DM. We sought to identify drivers of EC dysfunction using a combination of proteomic and transcriptomic approaches by measuring: serum O-link cardiovascular panels II and III along with insulin-mediated eNOS phosphorylation and miRNA profiling (NextGen sequencing) in isolated ECs. In 69 patients (37 with T2DM and 32 age- and sex-similar non-T2DM controls) proteomic analysis identified 35 upregulated and 6 downregulated (FDR p<0.05) proteins that included metabolic, vascular and fluid homeostasis, immune and apoptosis related biomarkers. Several biomarkers related to the degree of insulin-mediated eNOS phosphorylation in isolated EC: (renin r= -0.38, p=0.004, chymotrypsin C r= 0.37, p=0.006, paraoxinase 3, r= 0.35, p=0.009, lipoprotein lipase r= 0.34, p=0.01, superoxide dismutase 2 r= 0.31, p=0.02 and adrenomedullin r= -0.27, p=0.049). In a subset of 10 patients (5/group), we confirmed expression of EC-specific miRNA in ECs purified by CD144 microbeads. Comparing patients with T2DM and controls we found 6 upregulated and 7 downregulated miRNAs (FDR P<0.05). Ingenuity Pathway Analysis shows that these miRNAs are involved in the regulation of inflammation, glucose metabolism, stress signaling and cell cycle pathways. Further we found overlap of differentially expressed miRNA with predicted regulation of biomarkers that were altered in T2DM including: miR-4326 and miR-1270 regulate TNFRSF10A and ALCAM, while, miR-4433-5p and miR-342-3p are involved in regulation of superoxide dismutase 2. Our findings demonstrate that an association of circulating biomarkers particularly those that relate to fluid metabolism and oxidative stress with altered endothelial cell signaling in patients with T2DM. Further we have early evidence of altered non-coding miRNA expression in ECs in T2DM that may be related to inflammation and oxidative stress. Ongoing studies are evaluating the functional implications of altered miRNA expression in regulating vascular function in patients with T2DM.