Influence of a Hyperglycemic Microenvironment on a Healthy versus Diabetic Rat Vascular Endothelium Reveals Distinct Mechanistic and Phenotypic Responses
Authors: Haspula Dhanush , Vallejos Andrew , Hoffmann Brian 
Published: June 2021

Hyperglycemia is a critical factor in the development of vascular endothelial dysfunction in type 2 diabetes mellitus (T2DM). While hyperglycemic states are an independent risk factor for endothelial dysfunction, a pro‐inflammatory environment during diabetes is demonstrated to serve as a priming factor for hyperglycemia‐induced vascular damage. Whether hyperglycemic states result in a disruption of similar cellular pathways under both diabetic and non‐diabetic states, remains largely unknown. This study aimed to address this gap in knowledge through molecular and functional characterization of primary cardiac microvascular endothelial cells (RCMVECs) derived from the spontaneously T2DM Goto‐Kakizaki (GK) rat model in comparison to the control Wistar Kyoto (WKY) rat model under normal and hyperglycemic conditions. GK and WKY RCMVECs were cultured under both normal (NG; 4.5 mM) and high glucose (HG; 25 mM) conditions for two weeks, followed by tandem mass spectrometry (MS/MS), qPCR, tube formation assay (TFA), microplate based fluorimetry for reactive oxygen species (ROS), and mitochondrial respiration analyses. Following enrichment and pathway analyses of the tandem MS/MS and qPCR datasets, several molecular targets involved in angiogenic, redox and metabolic functions were significantly altered (FC>2; p<0.05) in the GK RCMVEC response to HG, but not in the WKY RCMVECs. Glycolytic enzymes were markedly reduced, and PMA‐induced superoxide production was enhanced in GK RCMVECs (HG vs NG; p<0.05). Additionally, insulin resistance genes were markedly altered in GK RCMVECs under HG conditions (p<0.05). While HG caused reduction in TFA parameters in WKY RCMVECs, GK RCMVECs exhibited fractured tubes under baseline conditions regardless of glycemic condition. Through the integration of high‐throughput tandem MS/MS analysis, bioinformatics analyses, transcriptomic analysis and in vitro functional assays, we identified a wide spectrum of molecular derangements in endothelial cells that were triggered by environmental (hyperglycemic) and/or genetic (diabetic permissive) determinants. We infer that the consequence of an incapacitated glycolytic machinery could well result in a greater reliance on the OXPHOS pathway in GK HG RCMVECs. This may lead to a significant superoxide burden and a spike in the levels of pro‐atherogenic factors. In conclusion, a hyperglycemia microenvironment exhibited distinct changes in the diabetic endothelial response as compared to those observed in healthy states.

Support or Funding Information

Support for this project has been provided by the National Institutes of Health National Institute of Diabetes and Digestive and Kidney Diseases (K01‐DK105043 to BRH) and the Department of Biomedical Engineering at the Medical College of Wisconsin and Marquette University, Milwaukee, WI, USA.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.