Abstract:

Objective To investigate the impact of blocking androgen receptor (AR) signaling pathway in the pathogenesis of male thoracic aortic dissection (TAD) and to uncover its molecular mechanisms. Methods In TAD clinical samples, animal models and primary cells, real-time quantitative polymerase chain reaction (RT-qPCR) and immunoblotting were used to detect the expression levels of AR and its pathway target gene FKBP5. Immunofluorescence was used to detect AR expression in primary cells isolated from TAD animal models. Immunohistochemistry was used to detect GPX4 expression in TAD animal models. In vascular smooth muscle cells (VSMCs), the AR signaling pathway was blocked to detect changes in oxidative stress and ferroptosis-related markers using biochemical assays. Luciferase reporter gene, chromatin immunoprecipitation, and nuclear run-on real-time transcription analysis were used to verify the transcriptional regulation of the key ferroptosis inhibitor gene long-chain acyl-CoA synthetase 3 (ACSL3) by the AR signaling pathway. In animal models, imaging and histological methods were employed to elucidate how the inhibition of the AR signaling pathway promotes the occurrence of TAD. Results Compared with normal aortic tissues, the expression of AR and its pathway target gene FKBP5, was reduced in tissues from male TAD patients and in the aortic VSMCs of male mouse TAD model tissues. Blocking the AR signaling pathway significantly reduced the expression levels of the ferroptosis inhibitor glutathione peroxidase 4(GPX4) in mouse aortic VSMCs, inducing the formation and rupture of TAD. Blocking the AR pathway induced the expression of oxidative stress and ferroptosis-related markers in VSMCs. Further research found that AR bound to the ACSL3 promoter region and promoted its transcription, inhibiting ferroptosis in VSMCs. Overexpression of ACSL3 reversed the ferroptosis induced by AR blockade. Animal experiments showed that blocking the AR signaling pathway promoted thoracic aortic lumen dilation, elastic fiber fragmentation, ultimately leading to TAD occurrence. Conclusions The AR signaling pathway inhibits ferroptosis in VSMCs through transcriptional activation of ACSL3. Loss of its function leads to elastic fiber fragmentation of the aortic wall, thereby promoting the occurrence and development of TAD.

Key words: Thoracic aortic dissection(TAD), Androgen receptor signaling pathway, Ferroptosis, Long-chain acyl-CoA synthetase 3(ACSL3), Vascular smooth muscle cell(VSMC)