MSCs Ameliorate Hepatic IR Injury by Modulating Phenotypic Transformation of Kupffer Cells Through Drp-1 Dependent Mitochondrial Dynamics.

BACKGROUND: Hepatic ischemia and reperfusion (IR) injury, characterized by reactive oxygen species (ROS) production and immune disorders, leads to exogenous antigen-independent local inflammation and hepatocellular death. Mesenchymal stem cells (MSCs) have been shown to be immunomodulatory, antioxidative and contribute to liver regeneration in fulminant hepatic failure. We aimed to investigate the underlying mechanisms by which MSCs protect against liver IR injury in a mouse model. METHODS: MSCs suspension was injected 30 min prior to hepatic warm IR. Primary kupffer cells (KCs) were isolated. Hepatic injury, inflammatory responses, innate immunity, KCs phenotypic polarization and mitochondrial dynamics were evaluated with or without KCs Drp-1 overexpression RESULTS: MSCs markedly ameliorated liver injury and attenuated inflammatory responses and innate immunity after liver IR injury. MSCs significantly restrained M1 phenotypic polarization but boosted M2 polarization of KCs extracted from ischemic liver, as demonstrated by lowered transcript levels of iNOS and IL-1ß but raised transcript levels of Mrc-1 and Arg-1 combined with p-STAT6 up-regulation and p-STAT1 down-regulation. Moreover, MSCs inhibited KCs mitochondrial fission, as evidenced by decreased Drp1 and Dnm2 levels. We overexpressed Drp-1 in KCs which promote mitochondrial fission during IR injury. the regulation of MSCs towards KCs M1/M2 polarization was abrogated by Drp-1 overexpression after IR injury. Ultimately, in vivo Drp-1 overexpression in KCs hampered the therapeutic effects of MSCs against hepatic IR injury CONCLUSIONS: We revealed that MSCs facilitated M1-M2 phenotypic polarization through inhibiting Drp-1 dependent mitochondrial fission and further attenuated liver IR injury. These results add a new insight into regulating mechanisms of mitochondrial dynamics during hepatic IR injury and may offer novel opportunities for developing therapeutic targets to combat hepatic IR injury.

Puerarin protects against high-fat high-sucrose diet-induced non-alcoholic fatty liver disease by modulating PARP-1/PI3K/AKT signaling pathway and facilitating mitochondrial homeostasis.

As yet, there was no effective pharmacological therapy approved for non-alcoholic fatty liver disease (NAFLD). Here, we aimed to evaluate the therapeutic potential of puerarin against NAFLD and explored the underlying mechanisms. C57BL/6J mice were fed with a high-fat high-sucrose (HFHS) diet with or without puerarin coadministration intragastrically. The levels of hepatocellular injury, steatosis, fibrosis, and mitochondrial and metabolism alteration were detected. First, puerarin ameliorated histopathologic abnormalities due to HFHS. We observed a marked increase in hepatic lipid content, inflammation, and fibrosis level, which were attenuated by puerarin. Possible mechanisms were related to puerarin-mediated activation of PI3K/AKT pathway and further improvement in fatty acid metabolism. Puerarin restored the NAD+ content and beneficially affected the hepatic mitochondrial function, which attenuated HFHS-induced steatosis and metabolic disturbances. Finally, hepatic PARP-1 was activated due to excessive fat intake. Puerarin attenuated the PARP-1 expression in HFHS-fed mice, and PJ34, the PARP inhibitor, could mimic these protections of puerarin. However, pharmacological inhibition of PI3K disabled the protection of puerarin or PJ34 toward NAD+ refilling and mitochondrial homeostasis. In conclusion, our findings indicated that puerarin could be a promising and practical therapeutic strategy in NAFLD through modulating PARP-1/PI3K/AKT signaling pathway and further facilitating mitochondrial function.