Ttyh3 ameliorates myocardial ischemia-reperfusion injury by activating Akt1 signaling to suppress apoptosis.

Myocardial ischemia-reperfusion injury (MIRI) poses significant challenges in cardiovascular therapeutics, with the molecular mechanisms underlying cardiomyocyte apoptosis remaining incompletely understood. This study identifies Ttyh3 as a critical regulator of MIRI and delineates its mechanistic pathway. In vivo and in vitro models revealed that Ttyh3 expression was significantly downregulated following myocardial ischemia-reperfusion (IR) and hypoxia-reoxygenation (HR) injury. Overexpression of Ttyh3 via AAV9 in mice markedly improved cardiac function-evidenced by enhanced ejection fraction (EF) and fractional shortening (FS)-and reduced infarct size. Concurrently, Ttyh3 overexpression attenuated mitochondrial dysfunction and apoptosis, suppressing pro-apoptotic Bax/cleaved caspase-3 while upregulating anti-apoptotic Bcl2. In vitro HR models mirrored these findings, confirming Ttyh3's anti-apoptotic role. Mechanistic studies revealed an association between Ttyh3 and Akt1, accompanied by enhanced Akt1 phosphorylation. Crucially, AKT inhibition largely abolished Ttyh3-mediated protection, confirming Akt1 activation as pivotal. Further, Ttyh3 knockdown or overexpression modulated the chaperonin subunit Cct3, a novel regulator linked to apoptosis regulation. Silencing Cct3 reversed Ttyh3-induced Akt1 phosphorylation and cardioprotection, establishing a Ttyh3-Cct3-p-Akt1 axis as central to mitigating apoptosis and IR injury. Collectively, these findings unveil Ttyh3 as a modulator of Akt1 signaling via Cct3, offering a promising therapeutic target to attenuate MIRI-driven cardiomyocyte apoptosis and mitochondrial damage. This study provides novel insights into the molecular interplay governing cardiac IR injury and underscores Ttyh3's potential for clinical translation.