Mechanistic study of cycloastragenol in improving heart failure by regulating PI3K/AKT/mTOR signaling and ferroptosis.

Abstract

Heart failure (HF) is the end stage of various cardiovascular diseases, and persistent myocardial injury and adverse remodeling are major causes of its high hospitalization and mortality rates worldwide. Therefore, it is important to identify key molecules and effective agents that can slow or reverse HF progression. Cycloastragenol (CAG) is an active compound derived from Astragalus and has anti-inflammatory, antioxidant, and tissue-protective effects. The present study aimed to clarify the protective role of CAG in HF and to determine whether this effect is related to the regulation of ferroptosis through the PI3K/AKT/mTOR signaling pathway. The results showed that PI3K/AKT/mTOR signaling activity was markedly decreased in myocardial tissue from HF rats, accompanied by impaired cardiac function, aggravated myocardial injury, enhanced inflammatory response, and increased myocardial fibrosis and hypertrophic remodeling. At the same time, GSH levels were decreased, whereas ROS, MDA, and Fe2+ levels were increased. In addition, GPX4 and FTH1 expression was downregulated, ACSL4 expression was upregulated, and the Prussian blue-positive area was increased, indicating marked ferroptosis-related abnormalities. After CAG treatment, these changes were improved to different degrees. CAG restored cardiac function, reduced serum NT-proBNP, CK-MB, and cTnI levels, decreased inflammatory factor expression, and alleviated myocardial fibrosis and hypertrophy. Meanwhile, PI3K/AKT/mTOR signaling activity was restored, and iron deposition, lipid peroxidation, and ferroptosis-related molecular abnormalities were alleviated. In vitro experiments further showed that, in an OGD-induced H9c2 cell injury model, CAG increased cell viability, reduced LDH release, attenuated the inflammatory response, and alleviated mitochondrial membrane potential loss, ROS accumulation, and ferroptosis-related protein abnormalities. C11-BODIPY 581/591 flow cytometry further demonstrated that CAG reduced OGD-induced lipid ROS accumulation and lipid peroxidation. In addition, the ferroptosis inhibitor ferrostatin-1 partially rescued OGD-induced cell injury, restored cell viability, reduced LDH release, and suppressed lipid ROS accumulation, further supporting the involvement of ferroptosis-related processes. Further intervention with the AKT inhibitor MK-2206 partially weakened the protective effects of CAG, supporting the involvement of AKT signaling in its protective action. In conclusion, the present study showed that CAG improved HF-related myocardial injury and myocardial remodeling by restoring PI3K/AKT/mTOR signaling activity and inhibiting ferroptosis-related processes, suggesting that CAG may be a potential therapeutic agent for HF.