Yes-Associated Protein Targets the Transforming Growth Factor β Pathway to Mediate High-Fat/High-Sucrose Diet-induced Arterial Stiffness

Background: Metabolic syndrome is related to cardiovascular diseases, which is attributed in part, to arterial stiffness; however, the mechanisms remain unclear. The present study aimed to investigate the molecular mechanisms of metabolic syndrome-induced arterial stiffness and to identify new therapeutic targets. Methods: Arterial stiffness was induced by high-fat/high-sucrose diet in mice, which was quantified by Doppler ultrasound. Four-dimensional label-free quantitative proteomic analysis, affinity purification and mass spectrometry, and immunoprecipitation and GST (glutathione S-transferase) pull-down experiments were performed to explore the mechanism of YAP (Yes-associated protein)-mediated TGF (transforming growth factor) beta pathway activation. Results: YAP protein was upregulated in the aortic tunica media of mice fed a high-fat/high-sucrose diet for 2 weeks and precedes arterial stiffness. Smooth muscle cell-specific YAP knockdown attenuated high-fat/high-sucrose diet-induced arterial stiffness and activation of TGF beta-Smad2/3 signaling pathway in arteries. By contrast, Myh11Cre(ERT2)-Yap(Tg) mice exhibited exacerbated high-fat/high-sucrose diet-induced arterial stiffness and enhanced TGF beta-activated Smad2/3 phosphorylation in arteries. PPM1B (protein phosphatase, Mg2+/Mn2+-dependent 1B) was identified as a YAP-bound phosphatase that translocates into the nucleus to dephosphorylate Smads (mothers against decapentaplegic homologs) in response to TGF beta. This process was inhibited by YAP through removal of the K63-linked ubiquitin chain of PPM1B at K326. Conclusions: This study provides a new mechanism by which smooth muscle cell YAP regulates the TGF beta pathway and a potential therapeutic target in metabolic syndrome-associated arterial stiffness.