SphK1 deficiency ameliorates the development of atherosclerosis by inhibiting the S1P/S1PR3/Rhoa/ROCK pathway

S1P is an important factor regulating the function of the vascular endothelial barrier. SphK1 is an important limiting enzyme for the synthesis of S1P. However, the role of the SphK1/S1P-mediated vascular endothelial barrier function in atherosclerosis has not been fully revealed. This study explored the roles and mechanisms of SphK1 on atherosclerosis in vivo and in vitro.

In vivo, ApoE^-/- and SphK1^-/-ApoE^-/- mice were fed a high-fat diet to induce atherosclerosis. In vitro, ox-LDL induced HUVECs to establish a cell model. Aortic histological changes were measured by H&E staining, Oil Red O staining, EVG staining, Sirius scarlet staining, immunofluorescence, and Evans Blue Assay. Western blotting was performed to explore the specific mechanism.

We validated that deficiency of SphK1 resulted in a marked amelioration of atherosclerosis, as indicated by the decreased lipid accumulation, inflammatory factors, oxidative stress, aortic plaque area, inflammatory factor infiltration, VCAM-1 expression, and vascular endothelial permeability. Moreover, deficiency of SphK1 downregulated the expression of aortic S1PR3, Rhoa, ROCK, and F-actin. The results of administration with the SphK1 inhibitor PF-543 and the S1PR3 inhibitor VPC23019 in vitro further confirmed the conclusion that deficiency of SphK1 reduced S1P level and S1PR3 protein expression, inhibited Rhoa/ROCK signaling pathway, regulated protein expression of F-actin, improved vascular endothelial dysfunction and permeability, and exerted anti-atherosclerotic effects.

This study revealed that deficiency of SphK1 relieved vascular endothelial barrier function in atherosclerosis mice via SphK1/S1P/S1PR signaling pathway.