Liver fibrosis is a wound‐healing response represented by excessive extracellular matrix deposition. Activation of hepatic stellate cell (HSC) is the critical cellular basis for hepatic fibrogenesis, whereas hepatocyte undergoes epithelial‐mesenchymal transition (EMT) which is also involved in chronic liver injury. Long noncoding RNA H19 has been found to be associated with cholestatic liver fibrosis lately. However, the role of H19 in liver fibrosis remains largely to be elucidated. In this study, we found that the expression of H19 was significantly upregulated in the liver tissue of CCl4‐induced mice, a toxicant‐induced liver fibrogenesis model. Overexpression of H19 significantly aggravated activation of HSC and EMT of hepatocyte both by stimulating transforming growth factor‐β (TGF‐β) pathway. In terms of mechanism, H19 functioned as a competing endogenous RNA to sponge miR‐148a and subsequently sustained the level of ubiquitin‐specific protease 4 (USP4), which was an identified target of miR‐148a and was able to stabilize TGF‐β receptor I. In conclusion, our findings revealed a novel H19/miR‐148a/USP4 axis which promoted liver fibrosis via TGF‐β pathway in both HSC and hepatocyte, indicating that H19 could become a promising target for the treatment of liver fibrosis.
The alteration of the enteric nervous system (ENS) and its role in neuroimmune modulation remain obscure in the pathogenesis of inflammatory bowel diseases (IBDs). Here, by using the xCell tool and the latest immunolabeling-enabled three-dimensional (3D) imaging of solvent-cleared organs technique, we found severe pathological damage of the entire ENS and decreased expression of choline acetyltransferase (ChAT) in IBD patients. As a result, acetylcholine (ACh), a major neurotransmitter of the nervous system synthesized by ChAT, was greatly reduced in colon tissues of both IBD patients and colitis mice. Importantly, administration of ACh via enema remarkably ameliorated colitis, which was proved to be directly dependent on monocytic myeloid-derived suppressor cells (M-MDSCs). Furthermore, ACh was demonstrated to promote interleukin-10 secretion of M-MDSCs and suppress the inflammation through activating the nAChR/ERK pathway. The present data reveal that the cholinergic signaling pathway in the ENS is impaired during colitis and uncover an ACh-MDSCs neuroimmune regulatory pathway, which may offer promising therapeutic strategies for IBDs.
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