HucMSC-Exo Promote Mucosal Healing in Experimental Colitis by Accelerating Intestinal Stem Cells and Epithelium Regeneration via Wnt Signaling Pathway.

Background: Mucosal healing has emerged as a crucial therapeutic goal for inflammatory bowel diseases (IBD). Exosomes (Exo) as a potential acellular candidate for stem cell therapy might be competent to promote mucosal healing, while its mechanism remains unexplored. Methods: Exosomes derived from human umbilical cord mesenchymal stem cells (hucMSCs) were subjected to experimental colitis mice intraperitoneally to estimate the role in mucosal healing and the regeneration of intestinal stem cells (ISCs) and epithelium. The intestinal organoid model of IBD was constructed utilizing tumor necrosis factor (TNF)-α for subsequent function analysis in vitro. Transcriptome sequencing was performed to decipher the underlying mechanism and Wnt-C59, an oral Wnt inhibitor, was used to confirm that further. Finally, the potential specific components of hucMSC­exo were investigated based on several existing miRNA expression datasets. Results: HucMSC-exo showed striking potential for mucosal healing in colitis mice, characterized by decreased histopathological injuries and neutrophil infiltration as well as improved epithelial integrity. HucMSC-exo up-regulated the expression of leucine-rich repeat-containing G-protein coupled receptor 5 (Lgr5), a specific marker for ISCs and accelerated the proliferation of intestinal epithelium. HucMSC-exo endowed intestinal organoids with more excellent capacity to grow and bud under TNF-α stimulation. More than that, the fact that hucMSC-exo activated the canonical Wnt signaling pathway to promote mucosal healing was uncovered by not only RNA-sequencing but also relevant experimental data. Finally, bioinformatics analysis of the existing miRNA expression datasets indicated that several miRNAs abundant in hucMSC-exo involved widely in regeneration or repair related biological processes and Wnt signaling pathway might be one of the most important signal transduction pathways. Conclusion: Our results suggested that hucMSC-exo could facilitate mucosal healing in experimental colitis by accelerating ISCs and intestinal epithelium regeneration via transferring key miRNAs, which was dependent on the activation of Wnt/ß-catenin signaling pathway.

CCN6 improves hepatic steatosis, inflammation, and fibrosis in non-alcoholic steatohepatitis.

BACKGROUND AND AIMS: CCN6 is a secretory protein with functions of maintaining mitochondrial homeostasis and anti-oxidative stress; and yet, whether it is involved in the pathogenesis of non-alcoholic steatohepatitis (NASH) is still obscure. We investigated the role and mechanism of CCN6 in the development of NASH. METHODS: Human liver tissue samples were collected to detect the expression profile of CCN6. High-fat-high-cholesterol (HFHC) and methionine choline-deficient (MCD) diet were applied to mice to establish NASH animal models. Liver-specific overexpression of CCN6 was induced in mice by tail vein injection of adeno-associated virus (AAV), and then the effect of CCN6 on the course of NASH was observed. Free fatty acid (FFA) was applied to HepG2 cells to construct the cell model of steatosis, and the effect of CCN6 was investigated by knocking down the expression of CCN6 through small interfering RNA (siRNA) transfection. RESULTS: We found that CCN6 expression was significantly downregulated in the liver of NASH. We confirmed that liver-specific overexpression of CCN6 significantly attenuated hepatic steatosis, inflammation response and fibrosis in NASH mice. Based on RNA-seq analysis, we revealed that CCN6 significantly affected the MAPK pathway. Then, by interfering with apoptosis signal-regulating kinase 1 (ASK1), we identified the ASK1/MAPK pathway pairs as the targets of CCN6 action. CONCLUSIONS: CCN6 protects against hepatic steatosis, inflammation response and fibrosis by inhibiting the activation of ASK1 along with its downstream MAPK signalling. CCN6 may be a potential therapeutic target for the treatment of NASH.

Exosomes derived from human umbilical cord mesenchymal stem cells ameliorate experimental non-alcoholic steatohepatitis via Nrf2/NQO-1 pathway.

BACKGROUND: No approved effective therapy for non-alcoholic steatohepatitis (NASH) is currently available. Exosomes derived from mesenchymal stem cells (MSCs) perform the functions such as inhibiting inflammation, anti-oxidative stress, regulating immunity, but it is not clear whether human umbilical cord mesenchymal stem cells (hUC-MSCs) exosomes protect against NASH through Nrf2/NQO-1 pathway. Therefore, this study was conducted to investigate the effects of hUC-MSCs exosomes on NASH through Nrf2/NQO-1 pathway in vivo and in vitro. METHODS: C57BL/6J male mice were fed with high fat and high cholesterol diet (HFHC) and methionine choline deficiency diet (MCD). Mice were treated with or without hUC-MSCs exosomes by tail intravenous injection. The liver histology, lipid metabolism and oxidative stress were evaluated. HepG2 and AML12 cells were incubated with palmitic acid (PA) and MCD conditioned medium, respectively. Then the therapeutic effect of hUC-MSCs exosomes in steatotic cells was evaluated. To elucidate the signaling pathways, the Nrf2-specific blocker ML385 was applied to intervene in vitro. RESULTS: In NASH models, hUC-MSCs exosomes attenuated steatosis in hepatocytes, altered the abnormal expression of lipid-related genes including SREBP-1c, PPAR-α, Fabp5, CPT1α, ACOX and FAS, suppressed the hepatic inflammatory responses by decreasing the expression of F4/80+ macrophages, CD11c+ macrophages as well as the content of TNF-α and IL-6. hUC-MSCs exosomes also inhibited oxidative stress by reducing the level of MDA, CYP2E1 and ROS, increasing the activity of SOD and GSH in hepatocytes. Notably, hUC-MSCs exosomes enhanced the protein ratio of p-Nrf2/Nrf2 and the protein expression of NQO-1. Moreover, in vitro, the therapeutic effects of hUC-MSCs exosomes on lipid deposition and ROS were reversed by ML385. Also, ML385 reduced the protein expression of p-Nrf2 and NQO-1 in vitro. CONCLUSION: Nrf2/NQO-1 antioxidant signaling pathway may play a key role in the treatment of NASH by hUC-MSCs exosomes.

Troxerutin attenuates cognitive decline in the hippocampus of male diabetic rats by inhibiting NADPH oxidase and activating the Nrf2/ARE signaling pathway.

Diabetes­associated cognitive decline is a recently identified a potential complication of diabetes. The present study was designed to examine the effects of troxerutin, a potent antioxidant, on cognitive function in rats with streptozotocin­induced diabetes and to further explore the potential underlying mechanisms. Cognitive functions were investigated by the Morris water maze test. The malondialdehyde (MDA) level and superoxide dismutase (SOD) activity in the hippocampus were assessed as the parameters of oxidative stress. Subunits of the NADPH oxidase (NOX) expression and nuclear factor erythroid 2­related factor 2/antioxidant responsive element (Nrf2/ARE) signaling pathway were detected to explore the potential underlying mechanisms. The water maze test revealed that troxerutin significantly improved cognitive impairment in diabetic rats. Troxerutin treatment attenuated oxidative stress in the hippocampus of diabetic rats, as evidenced by the decreased MDA level and the increased SOD activity. Moreover, troxerutin activated the Nrf2/ARE signaling pathway via Nrf2 nuclear translocation in the cells in the hippocampus of diabetic rats. Troxerutin elevated the expression levels of the antioxidant enzymes, heme oxygenase­1 (HO­1) and NAD(P)H:quinone oxidoreductase (NQO1), and decreased the expression levels of the NOX subunits, gp91phox, p47phox and p22phox. On the whole, these findings demonstrate that troxerutin exerts neuroprotective effects against diabetes­associated cognitive decline by suppressing oxidative stress in the hippocampus of rats with streptozotocin­induced diabetes. Troxerutin may thus prove to be a potential therapeutic medicine for the treatment of diabetes­associated cognitive decline.

MicroRNA-142-5p facilitates the pathogenesis of ulcerative colitis by regulating SOCS1.

BACKGROUND: Increasing evidence suggests that abnormal levels of microRNAs (miRNAs) are associated with ulcerative colitis (UC). It has been demonstrated that microRNA (miR)-142-5p was upregulated in UC patients. However, it remains unclear what the role of miR-142-5p is in UC. METHODS: Samples from patients with active UC and healthy controls were performed with miRNA microarray to identify miRNAs involved in the pathogenesis of UC. The results of quantitative RT-PCR verified that miR-142-5p was upregulated in UC patients. Meanwhile, the decreased expression of suppressor of cytokine signaling 1 (SOCS1) was also detected at mRNA and protein levels. The regulatory effect of miR-142-5p on SOCS1 was evaluated by luciferase reporter assay. Levels of IL-6 or IL-8 were detected by quantitative RT-PCR or enzyme-linked immunosorbent assay in HT-29 cells to evaluate the roles of SOCS1 or miR-142-5p in the progression of UC. RESULTS: The expression level of miR-142-5p was significantly upregulated and inversely correlated with SOCS1. Luciferase experiments showed that miR-142-5p interfered with the expression of SOCS1 by directly targeting its 3'-UTR. Furthermore, the level of miR-142-5p plays an important role in the secretion of IL-6 and IL-8. Moreover, lost function of SOCS1 reversed the miR-142-5p inhibitory effect. CONCLUSIONS: These results indicate that miR-142-5p improved the intestinal inflammation of active-UC patients by downregulating SOCS1 expression and increasing the cytokines IL-6 and IL-8 secretion.