Exosome-mediated macrophage regulation for inflammatory bowel disease repair: a potential target of gut inflammation.

Inflammatory bowel disease (IBD), which includes Crohn's disease (CD) and ulcerative colitis (UC), is a complex condition without a definite cause. During IBD, immune cells such as macrophages release proinflammatory cytokines and chemokines, contributing to intestinal barrier integrity dysfunction. IBD is largely influenced by macrophages, which are classified into subtypes M1 and M2. M1 macrophages have been found to contribute to the development of IBD, whereas M2 macrophages alleviate IBD. Hence, agents that cause increased polarization of the M2 phenotype could help repair IBD. Exosomes, as ubiquitous conveyors of intercellular messages, are involved in immune responses and immune-mediated disease processes. Exosomes and their microRNA (miRNA) from healthy cells have been found to polarize macrophages to M2 to repair IBD due to their anti-inflammatory properties; however, those from inflammatory-driven cells and disease cells promote M1 macrophages to perpetuate IBD. Here, we review the biogenesis, biochemical composition, and sources of exosomes, as well as the roles of exosomes as extracellular vesicles in regulation of macrophages to repair IBD.

[Effects of TUG1 on hepatic fibrosis and its mechanism].

Objective: To investigate the effects and mechanisms of taurine up-regulated gene 1 (TUG1) in hepatic fibrosis. Methods: According to the literature, the classic hepatic fibrosis model of rats induced by 1%DMN(1ml/kg/d) was established. The rats with hepatic fibrosis and activated hepatic stellate cells (HSC) were divided into model control group, negative control group (transfected with siRNA negative control), siRNA interference group (transfected with TUG1). At the end of the experiment, hematoxylin eosin (HE) staining was used to detect the pathological changes of liver tissue; reverse transcription polymerase chain reaction (RT-PCR) and Western blot were used to determine the expression levels of α-smooth muscle actin (α-SMA), TUG1, collagen I, matrix metalloproteinase-2 (MMP-2), tissue inhibitor of metalloproteinase-1 (TIMP-1), Smad2 and Smad3 in rat liver tissue and activated hepatic stellate cells. Results: Compared with the model control group, the protein and gene levels of TUG1 and α-SMA in the negative control group were increased significantly(P＜0.05). The protein and gene levels of TUG1, α-SMA, collagen I, MMP-2, TIMP-1, Smad2 and Smad3 in the liver tissue and activated hepatic stellate cells in the siRNA interference group were decreased (P＜0.05) while compared with the blank control group and the negative control group. There were no significant differences in the levels of TUG1, α-SMA, collagen I, MMP-2, TIMP-1, Smad2 and Smad3 in the liver tissue and activated hepatic stellate cells between the control group and the negative control group (P＞0.05). Conclusion: TUG1 level is elevated in hepatic fibrosis tissue and activated hepatic stellate cells. Silencing TUG1 may improve the pathological damage of hepatic fibrosis induced by 1% DMN by inhibiting the transforming growth factor(TGF-ß1)/ Smad signaling pathway.