Spermidine-enhanced autophagic flux improves cardiac dysfunction following myocardial infarction by targeting the
Jing Yan1,2,3, Jian-Yun Yan1,2,3, Yu-Xi Wang1,2,3
1Laboratory of Heart Center and Department of Cardiology, Heart Center, Zhujiang Hospital, Southern Medical University, Guangzhou, China.
Background And Purpose:
Spermidine, a natural polyamine, is abundant in mammalian cells and is involved in cell growth, proliferation, and regeneration. Recently, oral spermidine supplements were cardioprotective in age-related cardiac dysfunction, through enhancing autophagic flux. However, the effect of spermidine on myocardial injury and cardiac dysfunction following myocardial infarction (MI) remains unknown.
Experimental Approach:
We determined the effects of spermidine in a model of MI, Sprague-Dawley rats with permanent ligation of the left anterior descending artery, and in cultured neonatal rat cardiomyocytes (NRCs) exposed to angiotensin II (Ang II). Cardiac function in vivo was assessed with echocardiography. In vivo and in vitro studies used histological and immunohistochemical techniques, along with western blots.
Key Results:
Spermidine improved cardiomyocyte viability and decreased cell necrosis in NRCs treated with angiotensin II. In rats post-MI, spermidine reduced infarct size, improved cardiac function, and attenuated myocardial hypertrophy. Spermidine also suppressed the oxidative damage and inflammatory cytokines induced by MI. Moreover, spermidine enhanced autophagic flux and decreased apoptosis both in vitro and in vivo. The protective effects of spermidine on cardiomyocyte apoptosis and cardiac dysfunction were abolished by the autophagy inhibitor chloroquine, indicating that spermidine exerted cardioprotective effects at least partly through promoting autophagic flux, by activating the AMPK/mTOR signalling pathway.
Conclusions And Implications:
Our findings suggest that spermidine improved MI-induced cardiac dysfunction by promoting AMPK/mTOR-mediated autophagic flux.
Related Concept Videos
01:22PI3K/mTOR/AKT Signaling Pathway
03:03mTOR Signaling and Cancer Progression
The mTOR pathway or the...
01:19Interactions Between Signaling Pathways
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...
03:14Notch Signaling Pathway
The Notch gene came into the limelight in 1914 after the discovery that its mutation in Drosophila melanogaster leads to a serrated (or "notched") wing margin phenotype. It was not...
02:33Hedgehog Signaling Pathway
01:28Insulin: The Receptor and Signaling Pathways