title: miR-200b inhibits TNF-α-induced IL-8 secretion and tight junction disruption of intestinal epithelial cells in vitro.
abstract: Inflammatory bowel diseases (IBDs) are chronic, inflammatory disorders of the gastrointestinal tract with unclear etiologies. Intestinal epithelial cells (IECs), containing crypt and villus enterocytes, occupy a critical position in the pathogenesis of IBDs and are a major producer of immunoregulatory cytokines and a key component of the intact epithelial barrier. Previously, we have reported that miR-200b is involved in the progression of IBDs and might maintain the integrity of the intestinal epithelial barrier via reducing the loss of enterocytes. In this study, we further investigated the impact of miR-200b on intestinal epithelial inflammation and tight junctions in two distinct differentiated states of Caco-2 cells after TNF-α treatment. We demonstrated that TNF-α-enhanced IL-8 expression was decreased by microRNA (miR)-200b in undifferentiated IECs. Simultaneously, miR-200b could alleviate TNF-α-induced tight junction (TJ) disruption in well-differentiated IECs by reducing the reduction in the transepithelial electrical resistance (TEER), inhibiting the increase in paracellular permeability, and preventing the morphological redistribution of the TJ proteins claudin 1 and ZO-1. The expression levels of the JNK/c-Jun/AP-1 and myosin light chain kinase (MLCK)/phosphorylated myosin light chain (p-MLC) pathways were attenuated in undifferentiated and differentiated enterocytes, respectively. Furthermore, a dual-luciferase reporter gene detection system provided direct evidence that c-Jun and MLCK were the specific targets of miR-200b. Collectively, our results highlighted that miR-200b played a positive role in IECs via suppressing intestinal epithelial IL-8 secretion and attenuating TJ damage in vitro, which suggested that miR-200b might be a promising strategy for IBD therapy.
  This was the first time that the inhibitory role of miR-200b on intestinal epithelial inflammation and paracellular permeability has been reported. Moreover, we further divided the intestinal epithelial cells (IECs) into two differentiated conditions and investigated the distinct impacts of miR-200b. Finally, we put forward and proved that myosin light chain kinase (MLCK) was a novel target of miR-200b.
authors.affiliation: Department of Gastroenterology, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Yujie
authors.identifier: http://orcid.org/0000-0001-8256-5897
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Department of Gastroenterology, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhou
authors.affiliation: Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China; and.
authors.forename: Junkai
authors.initials: J
authors.lastname: Yan
authors.affiliation: Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China; and.
authors.forename: Zizhen
authors.initials: Z
authors.lastname: Gong
authors.affiliation: Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China; and.
authors.forename: Yongtao
authors.initials: Y
authors.lastname: Xiao
authors.affiliation: Department of Gastroenterology, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Cong
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Colorectal Surgery, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Du
authors.affiliation: Department of Gastroenterology, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; way_01chen@163.com.|Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China; and.
authors.forename: Yingwei
authors.initials: Y
authors.lastname: Chen
mesh_terms: D018938:Caco-2 Cells; D006801:Humans; D016209:Interleukin-8 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000166:cytology* / Q000473:pathology; D048031:JNK Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism; D019108:Tight Junctions / Q000502:physiology*; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D016209:Interleukin-8; C533896:MIRN200 microRNA, human; D035683:MicroRNAs; D018808:Transcription Factor AP-1; D014409:Tumor Necrosis Factor-alpha; D009219:Myosin-Light-Chain Kinase; D048031:JNK Mitogen-Activated Protein Kinases
keywords: IL-8; TNF-α; intestinal epithelial cell; miR-200b; tight junction