Molecular Targets of microRNAs during Liver Regeneration after Acute Injury: Recent Advances.

Experimental models using 2/3 partial hepatectomy or chemical injury have helped identify the pathways associated with liver regeneration (LR). Several microRNAs (miRNAs) have been identified as modulators of LR, but the molecular mechanisms underlying their activity are still unclear. Given the development of new therapies targeting miRNAs, this is an important question to address. This review discusses recent studies exploring the molecular mechanisms of miRNA-dependent regulation of LR. In particular, the finding that circ-RBM23 promotes LR by sequestering cytoplasmic miRNA139-5p has furthered the understanding of the molecular mechanisms underlying circRNA activity. Interestingly, although miRNAs are generally considered negative regulators of their target mRNAs, miRNAs182-5p promotes LR by upregulating Cyp7a. Furthermore, mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) were shown to enhance LR after 2/3 partial hepatectomy by releasing miRNAs that inhibit gene expression to promote an anti-inflammatory response or miRNA-regulatory factors. Since the administration of MSCs-EVs has no hepatotoxic side effects, this may represent a therapeutic strategy to promote LR. miRNAs also mediate LR after chemical injury. This is the case for miR194 and miR21, whose downregulation activates pro-regeneration pathways to ameliorate acetaminophen-induced liver injury. In addition, the downregulation of miR21 has been shown to improve autophagy and haemostasis after acetaminophen overdose. Although further studies are needed to improve their efficacy as therapeutics, the evidence gathered in this review has led to a better understanding of the molecular mechanisms associated with the control of LR by miRNAs. [ABSTRACT FROM AUTHOR]