Impact of CD36-mediated Endothelial Stiffening on Lesion Formation in Hypercholesterolemic Mice

Objective: To determine the impact of endothelial stiffening induced by CD36 (cluster of differentiation 36)-mediated lipid uptake on endothelial barrier disruption and the development of atherosclerosis in hypercholesterolemic mice. Approach and Results: Endothelial stiffening of intact en face monolayers, as assessed by atomic force microscopy, reveal the hyperlipidemic mouse model of atherosclerosis, LDLR -/- (low density lipoprotein receptor knockout) is significantly stiffer, especially in the atheroprone aortic arch, as compared to wild type controls (n=4 male mice with 8-15 tissue measurement sites per condition per mouse, p<0.05). Furthermore, there was a differential response in endothelial stiffness in males and females, with males having a greater endothelial stiffening. This difference correlated to a significantly greater plaque development, as analyzed using Oil O Red staining for lipids, in male HFD-fed LDLR -/- mice, as compared to age-matched females (n=5-6, p<0.05). Specific downregulation of endothelial CD36 in hypercholesterolemic Cdh5.CreERT2CD36 fl/fl LDLR -/- mice led to a significant decrease in endothelial stiffening (n=5 mice, p<0.05), both on chow and on HFD. Our data further reveal that prevention of HFD-induced endothelial stiffening by downregulation of CD36 is associated with a protective effect against endothelial barrier disruption in the hypercholesterolemic mouse model, as assessed by the penetration of Evan’s Blue Dye into the aortic wall. Evidence of the importance of CD36 is also demonstrated in atherosclerotic lesion formation, which is shown to be CD36-dependent (n=5-6 mice, p<0.05). Furthermore, a linear regression analysis of endothelial stiffness against percent plaque area across the two sexes, diet, and CD36 expression show a significant correlation (r = 0.84). Conclusions: This data suggests that endothelial CD36-dependent endothelial stiffening in intact aortas result in endothelial barrier disruption and promote atherosclerotic plaque formation. Supported by RO1HL073965, R01HL141120, RO1HL083298 (I. Levitan), NIA RO1AG044404 (J. Lee), and NHLBI T32 training appointment and UIC internal fellowship (V. Aguilar). This abstract was presented at the American Physiology Summit 2025 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.