Shear stress is uncoupled from atheroprotective KLK10 in atherosclerotic plaques.

Background And Aims: Physiological shear stress promotes vascular homeostasis by inducing protective molecules in endothelial cells (EC). However, physiological shear stress has been linked to atherosclerosis progression in some individuals with heightened cardiovascular risk. To address this apparent paradox, we hypothesized that diseased arteries may exhibit reduced responsiveness to the protective effects of physiological shear stress. Consequently, we compared the transcriptome of EC exposed to physiological shear stress in healthy arteries versus atherosclerotic conditions.

Methods: Employing 3D light sheet imaging and computational fluid dynamics, we identified NOS3 as a marker of physiological shear stress in both healthy and atherosclerotic murine arteries. Single-cell RNA sequencing was performed on EC from healthy (C57BL/6) mice, mildly diseased (Apoe normal diet) mice, and highly diseased (Apoe high fat diet) mice. The transcriptomes of Nos3 cells (exposed to physiological shear stress) were compared among the groups.

Results: Nos3 EC were associated with several markers of physiological shear stress in healthy arteries. Clustering of Nos3 EC revealed 8 different EC subsets that varied in proportion between healthy and diseased arteries. Cluster-specific nested functional enrichment of gene ontology terms revealed that Nos3 EC in diseased arteries were enriched for inflammatory and apoptotic gene expression. These alterations were accompanied by changes in several mechanoreceptors, including the atheroprotective factor KLK10, which was enriched in Nos3 EC in healthy arteries but markedly reduced in severely diseased arteries.

Conclusions: Physiological shear stress is uncoupled from atheroprotective KLK10 within atherosclerotic plaques. This sheds light on the complex interplay between shear stress, endothelial function, and the progression of atherosclerosis in individuals at risk of cardiovascular complications.