Abstract: Objective To investigate the mechanism of hepatitis C virus (HCV) core protein inducing incomplete mitophagy via activation of endocannabinoids system.Methods Hepatic stellate X-2 cells were co-cultured with HepG2 cells or HepG2 cells expressing HCV core protein. After co-culture, 2-arachidonoylglycerol (2-AG) level, reactive oxygen species (ROS) and activity of mitochondrial respiratory chain enzyme complexes were measured with liquid chromatography/mass spectrometry, flow cytometer and spectrophotometric method, respectively. Mitochondria membrane potential and calcium (Ca²⁺) concentration were detected with laser scanning confocal microscope. The levels of cannabinoid receptor 1(CB1R), phosphorylated serine-threonine kinase (p-Akt), mammalian target of rapamycin (mTOR), microtubule-associated protein 1 light chain 3 (LC3)-Ⅱ and p62 protein were measured using western blot. The levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were assayed with kit. All quantitative data was analyzed with t-test.Results In LX-2 cells co-cultured with HepG2 cells expressing HCV core protein, levels of 2-AG, ROS, Ca²⁺ concentration, MDA, CB1R protein and expression of LC3-Ⅱ protein were increased, while the activity of mitochondrial respiratory chain enzyme complexes, mitochondria membrane potential, SOD level, expression of p-Akt and p-mTOR protein were decreased compared with those in LX-2 cells co-cultured with HepG2 cells. However, the expression level of p62 protein did not change.Conclusion HCV core protein may not only increase 2-AG content, ROS level and Ca²⁺ concentration, but also up-regulate the expression of CB1R. Meanwhile, it may decrease mitochondria membrane potential, and down-regulate p-Akt and p-mTOR protein to induce incomplete mitophagy.

Key words: Hepatitis C virus, HCV, Core protein, Endocannabinoids system, Mitophagy