Affiliation:
1. Third Affiliated Hospital of Sun Yat-Sen University
Abstract
Abstract
Purpose: Mitophagy reduces mitochondrial dysfunction and
accumulation of reactive oxygen species (ROS) to prevent myocardial
injury in diabetic cardiomyopathy (DCM). Accumulated studies have
confirmed that metformin enhances autophagy to maintain
mitochondrial homeostasis and scavenge ROS. However, whether and
how metformin regulates mitophagy in cardiomyocytes remain
unclear.
Methods: Diabetic cardiomyopathy was modeled in H9c2
Cardiomyocytes treated with high glucose (30 mM) . Then high
Glucose-stimulated H9C2 cells were exposed to metformin, AMPKα
inhibitor and Sirt1 inhibitor for 24 h. Mitochondrial dysfunction
and mitophagy were detected by fluorescent probe
2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA), mitochondrial
membrane potential(MMP), flow cytometry and western blot.
Resluts: We found that the protein expression of Parkin, ROS
level, and mitochondrial membrane potential showed dynamic changes
in H9C2 cells under the stimulation of high glucose. Importantly,
metformin enhanced mitophagy, scavenged ROS, improved mitochondrial
function and inhibited apoptosis in H9C2 cells treated with high
glucose. Mechanistically, metformin increased the protein
expression of p-AMPKα, Sirt1, Parkin, and LC3-II in H9C2 cells
after a high glucose challenge. Depletion of AMPKα and Sirt1
abolished the increase of protein levels of Parkin and LC3-II and
mitophagy levels induced by metformin.
Conclusion: Our data indicated that metformin improves
mitochondrial dysfunction of H9C2 cells under hyperglycemia by
activating AMPKα/Sirt1/Parkin-mediated mitophagy, which provides
novel evidence for the treatment of DCM.
Publisher
Research Square Platform LLC