miR-200b-containing microvesicles attenuate experimental colitis associated intestinal fibrosis by inhibiting epithelial-mesenchymal transition.

BACKGROUND AND AIM: Epithelial-mesenchymal transition (EMT), characterized by the decrease of E-cadherin (E-Cad) and increase in vimentin and alpha-smooth muscle actin (α-SMA), was demonstrated to participate in inflammatory bowel disease-related fibrosis. miR-200b plays an anti-fibrosis role in inhibiting EMT by targeting ZEB1 and ZEB2. But the stability of exogenous miR-200b in blood limits its application. Microvesicles (MVs), which can transfer miRNAs among cells and prevent them from degradation, may provide an excellent transport system for the delivery of miR-200b in the treatment of fibrosis. METHODS: Bone marrow mesenchymal stem cells (BMSCs) were transfected with lentivirus to overexpress miR-200b. The MVs packaged with miRNA-200b were harvested for the anti-fibrotic treatment using in vitro (transforming growth factor beta 1-mediated EMT in intestinal epithelial cells: IEC-6) and in vivo (TNBS-induced intestinal fibrosis in rats) models. The pathological morphology was observed, and the fibrosis related proteins, such as E-Cad, vimentin, α-SMA, ZEB1, and ZEB2, were detected. RESULTS: MiR-200b-MVs would significantly reverse the morphology in TGF-ß1-treated IEC-6 cells and improve the TNBS-induced colon fibrosis histologically. The treatment of miR-200b-MVs increased miR-200b levels both in the IEC-6 cells and colon, resulting in a significant prevention EMT and alleviation of fibrosis. The expression of E-Cad was increased, and the expressions of vimentin and α-SMA were decreased. ZBE1 and ZEB2, the targets of miR-200b, were also decreased. CONCLUSIONS: miR-200b could be transferred from genetically modified BMSCs to the target cells or tissue by MVs. The mechanisms of miR-200b-MVs in inhibiting colonic fibrosis were related to suppressing the development of EMT by targeting ZEB1and ZEB2.

Role of DOR-ß-arrestin1-Bcl2 signal transduction pathway and intervention effects of oxymatrine in ulcerative colitis.

This study was aimed to investigate the role of the delta-opioid receptor (DOR)-ß-arrestin1-Bcl-2 signal transduction pathway in the pathogenesis of ulcerative colitis (UC) and the intervention effects of oxymatrine on UC. Forty Sprague-Dawley rats were divided into normal group, model group, oxymatrine-treated group and mesalazine-treated group (n=10 each) at random. The rat UC model was established by intra-colonic injection of trinitrobenzene sulfonic acid in the model group and two treatment groups. The rats in oxymatrine-treated group were subjected to intramuscular injection of oxymatrine [63 mg/(kg·day)] for 15 days, and those in mesalazine-treated group given mesalazine solution [0.5 g/(kg·day)] by gastric lavage for the same days. Animals in normal group and model group were administered 3 mL water by gastric lavage for 15 days. On the 16th day, after fasting for 24 h, the rats were sacrificed for the removal of colon tissues. The expression levels of DOR, ß-arrestin1 and Bcl-2 were determined in colon tissues by immunohistochemistry and real-time quantitative polymerase chain reaction (RT-PCR), respectively. It was found that the expression levels of DOR, ß-arrestin1 and Bcl-2 protein and mRNA were significantly increased in the model group as compared with the other groups (P<0.05). They were conspicuously decreased in both mesalazine-treated and oxymatrine-treated groups in contrast to the model group (P<0.05). No statistically significant difference was noted in these indices between mesalazine- and oxymatrinetreated groups (P>0.05). This study indicated that the DOR-ß-arrestin1-Bcl-2 signal transduction pathway may participate in the pathogenesis of UC. Moreover, oxymatrine can attenuate the development of UC by regulating the DOR-ß-arrestin1-Bcl-2 signal transduction pathway.

Extracellular Vesicles Derived from Bone Marrow Mesenchymal Stem Cells Protect against Experimental Colitis via Attenuating Colon Inflammation, Oxidative Stress and Apoptosis.

The administration of bone mesenchymal stem cells (BMSCs) could reverse experimental colitis, and the predominant mechanism in tissue repair seems to be related to their paracrine activity. BMSCs derived extracellular vesicles (BMSC-EVs), including mcirovesicles and exosomes, containing diverse proteins, mRNAs and micro-RNAs, mediating various biological functions, might be a main paracrine mechanism for stem cell to injured cell communication. We aimed to investigate the potential alleviating effects of BMSC-EVs in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis model. Intravenous injection of BMSC-EVs attenuated the severity of colitis as evidenced by decrease of disease activity index (DAI) and histological colonic damage. In inflammation response, the BMSC-EVs treatment significantly reduced both the mRNA and protein levels of nuclear factor kappaBp65 (NF-κBp65), tumor necrosis factor-alpha (TNF-α), induciblenitric oxidesynthase (iNOS) and cyclooxygenase-2 (COX-2) in injured colon. Additionally, the BMSC-EVs injection resulted in a markedly decrease in interleukin-1ß (IL-1ß) and an increase in interleukin-10 (IL-10) expression. Therapeutic effect of BMSC-EVs associated with suppression of oxidative perturbations was manifested by a decrease in the activity of myeloperoxidase (MPO) and Malondialdehyde (MDA), as well as an increase in superoxide dismutase (SOD) and glutathione (GSH). BMSC-EVs also suppressed the apoptosis via reducing the cleavage of caspase-3, caspase-8 and caspase-9 in colitis rats. Data obtained indicated that the beneficial effects of BMSC-EVs were due to the down regulation of pro-inflammatory cytokines levels, inhibition of NF-κBp65 signal transduction pathways, modulation of anti-oxidant/ oxidant balance, and moderation of the occurrence of apoptosis.

Intervention effects of QRZSLXF, a Chinese medicinal herb recipe, on the DOR-ß-arrestin1-Bcl2 signal transduction pathway in a rat model of ulcerative colitis.

ETHNOPHARMACOLOGICAL RELEVANCE: Qingre Zaoshi Liangxue Fang (QRZSLXF) is a Chinese medicinal herb recipe that is commonly prescribed for the treatment of ulcerative colitis. It includes 5 quality assured herbs: Sophora flavescens Aiton., Baphicacanthus cusia (Nees) Bremek., Bletilla striata Rchb.f., Glycyrrhiza uralensis Fisch. and Coptis chinensis Franch. The main phytochemical ingredient of QRZSLXF includes ammothamnine, sophocarpidine, liquiritin, berberine and indirubin. QRZSLXF has been clinically proven for use in the treatment of ulcerative colitis for over twenty years. In the past ten years, research has confirmed the therapeutic effect of QRZSLXF in ulcerative colitis and partially revealed its mechanism of action. Here, we further reveal the therapeutic mechanism of QRZSLXF in ulcerative colitis. To investigate the role of the DOR-ß-arrestin1-Bcl-2 signal transduction pathway in ulcerative colitis and to determine the effects of QRZSLXF on this signal transduction pathway. MATERIALS AND METHODS: Eighty-four Sprague-Dawley rats were randomly divided into six groups: normal control group, model group, mesalazine group, and QRZSLXF high-dose, medium-dose group and low-dose groups (n=14). Experimental colitis was induced by trinitrobenzenesulfonic acid (TNBS) in each group, except the normal control group. After modeling, bloody stool, mental state and diarrhea were observed and recorded. Two rats were randomly selected from the model groups adfnd sacrificed on day 3 to observe pathological changes in the colon tissue by microscopy. The rats in the QRZSLXF-treated groups received intramuscular injections of different concentrations of QRZSLXF for 15 days. The rats in the mesalazine group were treated with mesalazine solution (0.5 g/kg/day) by gastric lavage for 15 days. The rats in the normal control group and the model group were treated with 3 mL water by gastric lavage for 15 days. On the 16th day, after fasting for 24 h, the remaining rats were sacrificed and their colon tissues were used to detect the mRNA and protein expressions of DOR, ß-arrestin1 and Bcl-2 by Real-time PCR and immunohistochemistry, respectively. Histological changes in the colon tissues were also examined. RESULTS AND CONCLUSIONS: The expressions of DOR, ß-arrestin1 and Bcl-2 were significantly different among the four groups. The expressions of DOR, ß-arrestin1 and Bcl-2 protein and mRNA were significantly increased in the model group compared with the other groups (P<0.05). In contrast to the model group, the expressions of DOR, ß-arrestin1 and Bcl-2 were significantly decreased in the mesalazine group and the groups that received different doses of QRZSLXF (P<0.05), and there were no statistically significant differences among the mesalazine and QRZSLXF-treated groups (P>0.05). This study indicates that the DOR-beta-arrestin1-Bcl-2 signal transduction pathway may participate in the pathologic course of ulcerative colitis. Moreover, QRZSLXF could attenuate ulcerative colitis by regulating the DOR-ß-arrestin1-Bcl-2 signal transduction pathway.