Flow-mediated endothelial remodeling and inflammation drive developmental vascular susceptibility in ldlr loss of function

Atherosclerosis, the leading cause of cardiovascular disease, is associated with aberrant lipid metabolism, endothelial dysfunction, and chronic inflammation, yet its early manifestations and mechanisms remain incompletely understood. As low-density lipoprotein receptor loss of function is the most common monogenic cause of atherosclerosis, we employed low-density lipoprotein receptor knockout (ldlr-/-) zebrafish to investigate the developmental origins of atherosclerotic cardiovascular disease. Single-cell RNA-sequencing under differential flow conditions in embryonic ldlr-/- zebrafish identified a population of disproportionately stressed endothelial cells marked by overexpression of heat shock protein 70 (hsp70). Hsp70 is induced in stressed endothelial cells in a flow-dependent manner in zebrafish and a subset of human endothelial cells, and its activation is associated with disrupted remodeling angiogenesis in vivo. Genetic and pharmacological studies demonstrated that hsp70 upregulation inhibits vascular apoptosis and ciliogenesis, leading to altered angiogenic remodeling. Concurrently, pro-inflammatory processes, including enhanced myelopoiesis and thrombogenicity, are amplified at early stages in ldlr-/- zebrafish, which also exhibit impaired regenerative angiogenesis and heightened neutrophil recruitment post-vascular injury. Our findings reveal how abnormalities in flow-mediated endothelial remodeling and inflammation converge during embryogenesis to drive vascular susceptibility to hemodynamic and other stressors in ldlr loss of function.