Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 20 5 2021 09 28 550 562 Alireza Moulazadeh Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran AND Noncommunicable Disease Research Center, Fasa University of Medical Sciences, Fasa, Iran Sara Soudi Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran Bita Bakhshi Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran 2020 12 20 2021 08 04 Inflammation-induced by the interaction of the Vibrio cholerae with the epithelial cells is considered as a main cause of bacteria spreading through the gastrointestinal tract and its consequences. Because of the immunomodulatory and antibacterial properties of adipose-derived mesenchymal stem cells (AD-MSCs), this study aimed to investigate the effect of AD-MSCs on the interaction of the bacterial-epithelial cell. Caco-2 differentiated to intestinal epithelial cells co-cultured with AD-MSCs in a 1:1 ratio of the surface area of six-well plates, for 48 hours. After exposure to Vibrio cholerae, bacterial attachment and internalization were evaluated. Secretions of interleukin (IL) -6, prostaglandin E2 (PGE2), and nitric oxide (NO) were also measured using ELISA, and Griess assay, respectively. In addition, the expression of chloratoxin (Ctx-β) and inflammatory cytokines such as TNF-α, IL-1β, and IL-8 were evaluated by real-time polymerase chain reaction (RT-PCR). The rate of apoptosis was also evaluated by Annexin V-PI flow cytometry. Bacterial attachment and Ctx-β expression were significantly reduced in the co-culture group compared to the Vibrio cholerae-exposed Caco-2. IL-6 and PGE2 secretion increased in the co-culture group. NO, was also slightly reduced in exposure to Vibrio cholerae. An elevated level of bacterial internalization was observed in the co-culture group compared to the Caco-2 cells leading to an increase in the expression of pro-inflammatory cytokines. The rate of apoptosis was also increased significantly. Cell-to-cell contact of AD-MSCs and Caco-2 promoted inflammatory responses and disruption of the epithelium barrier by enhancing bacterial invasion. This may be due to the high expression of surface matrix metalloproteinases on MSCs.  https://ijaai.tums.ac.ir/index.php/ijaai/article/view/3073 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/3073/1750