Yin Mingming, Yan Xuebing, Weng Wenhao, Yang Yongzhi, Gao Renyuan, Liu Minfeng, Pan Cheng, Zhu Qi, Li Hao, Wei Qing, Shen Tongyi, Ma Yanlei, Qin Huanlong
Department of GI Surgery, Shanghai Tenth People's Hospital Affiliated to Tongji University, Shanghai, China.
Department of General Surgery, Anhui NO.2 Province People's Hopital, Hefei, China.
Cell Physiol Biochem. 2018;45(2):474-490. doi: 10.1159/000487027. Epub 2018 Jan 25.
BACKGROUND/AIMS: Recent studies have demonstrated that the manipulation of the gut microbiome represents a promising treatment for inflammatory bowel disease (IBD). We previously identified micro integral membrane protein (MIMP) as the smallest domain of surface layer protein from Lactobacillus Plantarum. However, the therapeutic relevance of MIMP in IBD remains unknown.
We initially employed a dextran sodium sulphate (DSS)-induced colitis model and evaluated the effect of MIMP on the inflammation response, intestinal barrier and gut microbiota using histological examination, Fluorescein isothiocyanate-Dextran detection and pyrosequencing analysis respectively. We then established peripheral blood mononuclear cells (PBMCs) and an epithelial CaCO-2 co-culture model to investigate the regulatory role of MIMP in inflammatory cytokines. The level changes of inflammatory cytokines were detected using Enzyme-linked immunosorbent and real-time polymerase chain reaction assay. The involved regulatory mechanisms were investigated mainly using dual luciferase reporter and chromatin immunoprecipitation assay.
In the DSS-induced colitis model, we observed that MIMP intervention effectively improved the body weight loss, increased the colon length and decreased disease activity index. Consistently, the inflammation scores in the MIMP treatment group were significantly lower than those in the DSS treatment group. Furthermore, MIMP intervention was found to successfully neutralize DSS treatment by decreasing the expression of pro-inflammatory cytokines (IFN-γ, IL-17 and IL-23) and increasing the expression of anti-inflammatory cytokines (IL-4 and IL-10). Notably, the permeability assay demonstrated that the MIMP treatment group was remarkably lower than that in the DSS treatment group. We also showed that MIMP improved gut microbiota dysbiosis caused by DSS-induced inflammation. Additionally, in PBMCs and the CaCO-2 co-culture model, MIMP showed an obvious suppressive effect on lipopolysaccharide-induced inflammation in a time- and dose-dependent manner. Furthermore, we revealed that MIMP could modulate inflammatory cytokine expression through the toll-like receptor 4 pathway and histone acetylation.
Our results suggested that MIMP showed a significant anti-inflammatory effect through regulating the gut barrier, microbiota and inflammatory cytokines. MIMP may have translational relevance as clinically relevant therapy for IBD patients.
背景/目的：最近的研究表明，肠道微生物群的调控是治疗炎症性肠病（IBD）的一种有前景的方法。我们之前将微小整合膜蛋白（MIMP）鉴定为植物乳杆菌表层蛋白的最小结构域。然而，MIMP在IBD中的治疗相关性仍然未知。
我们最初采用葡聚糖硫酸钠（DSS）诱导的结肠炎模型，分别通过组织学检查、异硫氰酸荧光素-葡聚糖检测和焦磷酸测序分析，评估MIMP对炎症反应、肠道屏障和肠道微生物群的影响。然后我们建立了外周血单核细胞（PBMC）和上皮CaCO-2共培养模型，以研究MIMP在炎性细胞因子中的调节作用。使用酶联免疫吸附测定和实时聚合酶链反应测定来检测炎性细胞因子的水平变化。主要使用双荧光素酶报告基因和染色质免疫沉淀测定来研究相关的调节机制。
在DSS诱导的结肠炎模型中，我们观察到MIMP干预有效地改善了体重减轻，增加了结肠长度并降低了疾病活动指数。同样，MIMP治疗组的炎症评分明显低于DSS治疗组。此外，发现MIMP干预通过降低促炎细胞因子（IFN-γ、IL-17和IL-23）的表达并增加抗炎细胞因子（IL-4和IL-10）的表达，成功抵消了DSS治疗的作用。值得注意的是，通透性测定表明MIMP治疗组明显低于DSS治疗组。我们还表明，MIMP改善了由DSS诱导的炎症引起的肠道微生物群失调。此外，在PBMC和CaCO-2共培养模型中，MIMP对脂多糖诱导的炎症表现出明显的抑制作用，且具有时间和剂量依赖性。此外，我们揭示了MIMP可以通过Toll样受体4途径和组蛋白乙酰化来调节炎性细胞因子的表达。
我们的结果表明，MIMP通过调节肠道屏障、微生物群和炎性细胞因子表现出显著的抗炎作用。MIMP作为IBD患者的临床相关治疗方法可能具有转化相关性。
