Platelet microparticles-derived miR-25-3p promotes the hepatocyte proliferation and cell autophagy via reducing B-cell translocation gene 2

Platelets are critical regulators of liver regeneration, but the mechanisms are still not fully understood. Platelets have been shown to contain a wide variety of microRNAs (miRNAs) and play an important role in many diseases. However, the mechanism that how the platelet microparticles (PMPs)-derived miRNA regulate the hepatocyte proliferation is not very clear. In this study, we have successfully isolated and identified PMPs. We also found that PMPs, which could be well integrated into the HHL-5 cells, could upregulate the level of miR-25-3p in HHL-5 cells. Meanwhile, we found that PMPs-derived miR-25-3p promoted HHL-5 cells proliferation by accelerating cells into the S phase, and enhanced the autophagy by increasing the LC3II expression and reducing the P62 expression. Then, we proved that the miR-25-3p could target the B-cell translocation gene 2 (BTG2) and downregulate the expression levels of the BTG2 gene in HHL-5 cells. In addition, the overexpression of BTG2 significantly inhibited the proliferation and autophagy abilities of HHL-5 cells, while cotransfected miR-25-3p mimics or PMPs could partially rescue HHL-5 cells proliferation and autophagy. Furthermore, we proved that PMPs accelerated hepatocyte proliferation by regulating autophagy pathways. Therefore, PMPs-derived miR-25-3p promoted HHL-5 cell proliferation and autophagy by targeting BTG2, which may be a new therapeutic method for liver regeneration.