Diabetes markedly increases the risk of cardiovascular disease (CVD), primarily through endothelial dysfunction driven by chronic hyperglycemia and oxidative stress. Cluster of Differentiation 36 (CD36), a fatty acid translocase and scavenger receptor, is known to contribute to lipid uptake, inflammation, and oxidative stress in vascular cells. Recent evidence suggests that CD36 is also present in mitochondria, indicating a potential role in mitochondrial fatty acid metabolism. Therefore, this study aims to explore the function of mitochondrial CD36 in lipid metabolism under conditions of obesity and hyperglycemia. To achieve this, human adipose microvascular endothelial cells (HAMECs) were exposed to elevated glucose with or without fatty acids (FAs) to mimic hyperglycemic and obesogenic conditions. Cells treated with both glucose and FAs exhibited significantly higher superoxide production compared to those treated with either alone, suggesting synergistic oxidative stress. CD36 knockdown reduced this effect, confirming its involvement in ROS generation. Western blotting, flow cytometry, and immunocytochemistry revealed that glucose exposure for 72 hours upregulated total CD36 expression but not its membrane localization. Fatty acid uptake (FAU) assays showed a significant CD36 dependent increase in lipid transport. These findings led us to explore the role of mitochondrial CD36 (mitoCD36) in endothelial cell (EC) lipid metabolism. TOM40-based mitochondrial isolation and MitoTracker colocalization confirmed the presence of CD36 in EC mitochondria, while Western blotting of purified mitochondrial protein demonstrated enhanced mitochondrial CD36 expression under high-glucose conditions. Flow cytometry data revealed that mitochondrial CD36 facilitated fatty acid transfer into endothelial mitochondria, and this process is upregulated when treated with high glucose. This result leads to increased mitochondrial reactive oxygen species (mitoROS) generation. Collectively, these findings reveal a novel mechanism linking glucose-induced mitochondrial CD36 upregulation to endothelial oxidative injury, highlighting its potential contribution to vascular dysfunction and CVD progression in diabetes. Funding source: Institutional Development Award (IDeA) of the National Institute of General Medical Sciences of the National Institutes of Health under award number 2P20GM113125. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.
Kashyap et al. (Fri,) studied this question.