An investigation of a new therapeutic target on atherosclerosis

Background: Atherosclerotic cardiovascular diseases associated with elevated blood lipid levels and vascular remodeling remain one of the major global health threats, although several therapies are currently available to control blood lipids in clinical practice. New treatments are urgently needed to treat atherosclerotic cardiovascular diseases. Endothelial cells are essential for maintaining vascular homeostasis, while endothelial–mesenchymal transition (EndMT) contributes to the formation of atherosclerotic plaques. This study aims to investigate a new therapeutic target that maintains endothelial health and inhibits the development of atherosclerosis.
Methods: Immunostaining was used to detect the expression and distribution of proteins in atherosclerotic arteries and cultured endothelial cells. RNA sequencing was performed to analyze the mRNA expression profile and enriched pathways. Real-time PCR and western blot were used to determine the expression of genes, transcriptionally and translationally.
Results: The expression and phosphorylation of TANK-binding kinase 1 (TBK1) were increased in atherosclerotic mouse aortas, and the results of immunostaining show that increased phosphorylated TBK1 was mainly localized in the endothelium. We also found that the phosphorylation of TBK1 in human endothelial cells was induced by oscillatory shear stress in a time-dependent manner, suggesting that oscillatory shear stress-induced endothelial TBK1 activation is likely involved in the development of endothelial dysfunction and atherosclerosis. We next overexpressed the constitutive TBK1 in human endothelial cells and performed RNA sequencing analysis. Atherosclerosis and EMT signaling pathways were top enriched by GAD and KEGG pathway analysis in human endothelial cells overexpressed with constitutive TBK1, which was confirmed by real-time PCR, western blot, and immunostaining. The expression of EndMT markers was indeed induced by constitutive TBK1 overexpression in human endothelial cells. Interestingly, TBK1 inhibition by its specific inhibitor GSK8612 suppressed inflammatory cytokines- or LPS-induced EndMT. Oral treatment of GSK8612 (1 mg/kg/day) for one month in ApoE knockout mice exerted an inhibitory effect on the formation of atherosclerotic plaques and suppressed the expression of EndMT markers in mouse aortas without alteration of metabolic parameters.
Conclusions: The present study reveals that endothelial TANK-binding kinase 1 is a novel therapeutic target of anti-EndMT and antiatherogenesis. TBK1 inhibitors may act as potentially effective drugs for the treatment of patients with atherosclerotic vascular disease. This study is supported by HMRF 07181286 and SRFS2021-4S04.