[Mechanism of ginsenoside Rg_1 in regulating autophagy through miR-155/Notch1/Hes1 pathway to attenuate hypoxia/reoxygenation injury in HL-1 cells].

This article explored the specific mechanism by which ginsenoside Rg_1 regulates cellular autophagy to attenuate hypoxia/reoxygenation(H/R) injury in HL-1 cardiomyocytes through the microRNA155(miR-155)/neurogenic gene Notch homologous protein 1(Notch1)/hairy and enhancer of split 1(Hes1) pathway. An HL-1 cell model with H/R injury was constructed, and ginsenoside Rg_1 and/or Notch1 inhibitor DAPT and miR-155 mimics were used to treat cells. Cell counting kit(CCK)-8 was used to detect the relative viability of HL-1 cells with H/R injury. The lactate dehydrogenase(LDH) content in cell culture medium supernatant was detected by using an LDH assay kit, and autophagosome in cells was observed by transmission electron microscopy. The level of autophagy in cells was detected through the mono-dansyl-cadaverine(MDC) detection method. Fluorescence quantitative polymerase chain reaction was used to detect the mRNA levels of miR-155, Notch1, Hes1, and microtubule-associated protein1 light chain 3(LC3), and Western blot was used to detect the protein expression levels of Notch1, Hes1, LC3Ⅰ, and LC3Ⅱ. The results show that after H/R injury, the activity of HL-1 cells decreases, and LDH leakage increases. Besides, the number of intracellular autophagosomes increases, and the mRNA level of LC3 and the LC3Ⅱ/LC3Ⅰ ratio are elevated. In addition, ginsenoside Rg_1 can increase cell activity, decrease LDH leakage and the number of intracellular autophagosomes, and reduce the mRNA level of LC3 and the LC3Ⅱ/LC3Ⅰ ratio. Therefore, it plays a cardioprotective role by inhibiting autophagy, and Notch1 inhibitor or miR-155 overexpression can inhibit the effect of ginsenoside Rg_1, promote autophagy, and aggravate H/R injury in HL-1 cells. Ginsenoside Rg_1 can inhibit the reduction of Notch1 and Hes1 mRNA levels and protein expressions and the increase in miR-155 mRNA levels caused by H/R injury, while Notch1 inhibitors or miR-155 overexpression show the opposite effect. In summary, ginsenoside Rg_1 can regulate autophagy through the miR-155/Notch1/Hes1 pathway to alleviate H/R injury in HL-1 cardiomyocytes.