hESC-Derived Epicardial Cells Promote Repair of Infarcted Hearts in Mouse and Swine.

Myocardial infarction (MI) causes excessive damage to the myocardium, including the epicardium. However, whether pluripotent stem cell-derived epicardial cells (EPs) can be a therapeutic approach for infarcted hearts remains unclear. Here, the authors report that intramyocardial injection of human embryonic stem cell-derived EPs (hEPs) at the acute phase of MI ameliorates functional worsening and scar formation in mouse hearts, concomitantly with enhanced cardiomyocyte survival, angiogenesis, and lymphangiogenesis. Mechanistically, hEPs suppress MI-induced infiltration and cytokine-release of inflammatory cells and promote reparative macrophage polarization. These effects are blocked by a type I interferon (IFN-I) receptor agonist RO8191. Moreover, intelectin 1 (ITLN1), abundantly secreted by hEPs, interacts with IFN-ß and mimics the effects of hEP-conditioned medium in suppression of IFN-ß-stimulated responses in macrophages and promotion of reparative macrophage polarization, whereas ITLN1 downregulation in hEPs cancels beneficial effects of hEPs in anti-inflammation, IFN-I response inhibition, and cardiac repair. Further, similar beneficial effects of hEPs are observed in a clinically relevant porcine model of reperfused MI, with no increases in the risk of hepatic, renal, and cardiac toxicity. Collectively, this study reveals hEPs as an inflammatory modulator in promoting infarct healing via a paracrine mechanism and provides a new therapeutic approach for infarcted hearts.

Asiatic acid alleviates ischemic myocardial injury in mice by modulating mitophagy- and glycophagy-based energy metabolism.

Myocardial infarction (MI) causes disturbances in myocardial energy metabolism, ultimately leading to a poor prognosis. Cytosolic glycogen autophagy (glycophagy) and mitochondrial autophagy (mitophagy) are upregulated in MI to optimize energy metabolism but to a limited extent. Asiatic acid (AA), a pentacyclic triterpene derived from the traditional Chinese herb Centella asiatica, displays anti-inflammatory, antioxidant, and antiapoptotic activities. AA has been found to alleviate focal cerebral and liver ischemic injury by reversing mitochondrial dysfunction. In this study, we investigated whether AA exerted cardioprotective effects against MI by activating glycophagy and mitophagy to improve the energy balance. In vitro cardioprotective effects were examined in neonatal mouse cardiomyocytes subjected to oxygen-glucose deprivation for 12 h. Treatment with AA (2-50 µM) significantly increased cell viability and improved the energy metabolism evidenced by increased ATP level and phosphocreatine/ATP ratio. In vivo cardioprotective effects were studied in a mouse model of MI. Administration of AA (5-125 mg·kg-1·d-1, ig) significantly reduced infarct size and ischemic myocardial injury, and improved cardiac function. AA treatment also promoted mitophagy and relieved mitochondrial edema evidenced by increased number of mitophagosomes in ischemic myocardium in vivo and increased mitochondria-light chain 3 (LC3)-II colocalization in ODG-treated cardiomyocytes in vitro. Mitophagy activation was accompanied by activation of the AMPK signaling pathway. Knockdown of AMPK abolished AA-activated mitophagy. Furthermore, we showed that glycophagy was upregulated in OGD cardiomyocytes evidenced by increased starch binding domain protein 1 (STBD1)-GABA type A receptor-associated protein-like 1(GABARAPL1) interaction and extracellular acidification rate, whereas AA treatment further promoted glycophagy accompanied by PI3K/Akt activation. PI3K inhibitor LY294002 or Akt inhibitor GSK690693 blocked the effects of AA on glycophagy and glycolysis. Finally, simultaneous inhibition of glycophagy and mitophagy abolished the cardioprotective effects and energy regulation of AA. These results demonstrate that AA protects ischemic cardiomyocytes by modulating glycophagy- and mitophagy-based energy metabolism through the PI3K/Akt and AMPK pathways.