Endothelial Calcium Dynamics and RNA Expression Following Partial Carotid Artery Ligation in Mice

Under conditions of normal laminar blood flow, shear stress along the arterial endothelium preserves vascular homeostasis. Correspondingly, disruption of shear stress along the vascular wall underlies progressive endothelial dysfunction and vascular wall remodeling associated with atherosclerosis. Recent findings suggest distinct changes in the profile of spatially and temporally dynamic Ca 2+ signals along the endothelial network may play an early and critical role in the pathologic transition to disease under low flow conditions. Here we employ a carotid artery partial ligation (PL) mouse model to study progressive effects of disrupted flow on endothelial Ca 2+ handling proteins at progressive time points (1, 7, and 14 days) and corresponding changes in Ca 2+ signaling. For these studies, left carotid arteries (LCA) of anesthetized mice were surgically ligated (leaving only the superior thyroid artery patent) while right carotid arteries (RCA) were left open and used as controls. Ultrasound was performed at indicated time points to track LCA and RCA blood flow profiles. Following euthanasia, arteries were harvested and subjected to 1) endothelial cell isolation followed by RNA seq analysis, 2) sectioning for immunostaining, or 3) preparation for confocal imaging of endothelial Ca 2+ signals. Ultrasound measurements revealed an approximately 90% reduction of flow in ligated arteries (LCA) by day 1 post-ligation. In LCA vs RCA, expression of crucial Ca 2+ handling/regulating proteins was altered, including small conductance Ca 2+ -activated K + channels (K Ca 2.2/3/4), type IV vanilloid transient receptor potential channels (TRPV4), and sarcoplasmic endoplasmic reticulum Ca 2+ ATPase (SERCA3). These proteins were markedly downregulated within 24 hours of flow disruption, with further reductions observed at 7 days. Downregulation of Ca 2+ handling proteins corresponded with progressive truncation of Ca 2+ signal frequency and area along the endothelial network. Our findings suggest that an altered expression of certain Ca 2+ handling proteins is an early consequence of blood flow disruption, leading to distinct shifts in the dynamic endothelial Ca 2+ signaling profile that underlies progressive dysfunction and structural remodeling in low-flow vascular disease. This work was supported by R01HL155288 and P01HL066299 from the National Institutes of Health 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.