JTC801 inhibited CA9 activation via HIF-1α to promotes alkaliptosis in vascular smooth muscle cells and alleviate the formation of aortic dissection.

Abstract

BACKGROUND: Aortic dissection (AD) is a life-threatening cardiovascular condition characterized by high morbidity and mortality rates. However, the molecular mechanism of intracellular pH in AD development has not been fully elucidated. In this study, the role of carbonic anhydrase 9 (CA9) in VSMCs intracellular pH and the regulatory mechanism were investigated. METHODS: Cell viability was examined by cell counting kit-8 (CCK-8) and intracellular pH was detected by BCECF-AM probe. The regulation of CA9 transcription by HIF-1α was measured by Cut &run-qPCR assay. The levels of CA9, HIF-1α, MMP2 and α-SMA were evaluated by RT-qPCR, Western blot and Immunofluorescence. RESULTS: Our results demonstrated that CA9 was significantly upregulated in AD tissues, primarily localized in VSMCs, and associated with increased MMP2 levels, while α-SMA levels decreased. Silencing CA9 in VSMCs resulted in reduced cell viability and increased intracellular pH. Additionally, we found that HIF-1α was upregulated in AD, regulating CA9 expression in VSMCs. Treatment with JTC801 in a BAPN-induced mouse model reduced CA9 and HIF-1α expression, improving survival and decreasing AD incidence. CONCLUSION: This study establishes CA9 as a hypoxia-responsive mediator of pH dysregulation in AD, modulated by HIF-1α. Targeting the HIF-1α/CA9 axis with JTC801 presents a novel therapeutic strategy to restore VSMC homeostasis and ECM integrity. These findings advance our understanding of intracellular pH in AD and highlight this approach may be a potential therapeutic target.