期刊
BMC MICROBIOLOGY
卷 15, 期 -, 页码 -出版社
BMC
DOI: 10.1186/s12866-015-0546-x
关键词
L. acidophilus; Synbiotics; Salmonella; TGF-b; NF-kappa B; MIR21; SMAD
类别
资金
- Kaohsiung Veterans General Hospital [VGHKS102-97, VGHNSU103-004, VGHKS100-125]
- Zuoying Branch of Kaohsiung Armed Forces General Hospital [ZBH 104-26]
- Kaohsiung Medical University [KMU-TP103A33]
Background: Salmonella is a common intestinal pathogen that causes acute and chronic inflammatory response. Probiotics reduce inflammatory cytokine production and serve as beneficial commensal microorganisms in the human gastrointestinal tract. TGF-beta (transforming growth factor beta)/SMAD and NF-kappa B signaling play important roles in inflammation in intestinal cells. However, the involvement of the signaling in regulating inflammation between Salmonella and probiotics is not fully understood. Methods: L. acidophilus and prebiotic inulin were used to treat human intestinal Caco-2 cells prior to infection with Salmonella. The cells were harvested to examine the cytokines and MIR21 expression with immunoblotting and real-time PCR. NF-kappa B and SMAD3/4 reporter vectors were transfected into cells to monitor inflammation and TGF-beta 1 signaling, respectively. Results: In this study, we showed that the probiotic L. acidophilus decreased Salmonella-induced NF-kappa B activation in human intestinal Caco-2 cells. Expression of the inflammatory cytokines, TNF-alpha and IL-8, in L. acidophilus-pretreated cells was also significantly lower than that in cells infected with Salmonella alone. Moreover, TGF-beta 1 and MIR21 expression was elevated in cells pretreated with L. acidophilus or synbiotic, a combination of inulin and L. acidophilus, compared to that in untreated cells or cells infected with S. typhimurium alone. By contrast, expression of SMAD7, a target of MIR21, was accordingly reduced in cells treated with L. acidophilus or synbiotics. Consistent with TGF-beta 1/MIR21 and SMAD7 expression, SMAD3/4 transcriptional activity was significantly higher in the cells treated with L. acidophilus or synbiotics. Furthermore, TGF-beta 1 antibody antagonized the SMAD3/4 and NF-kappa B transcriptional activity modulated by L. acidophilus in intestinal cells. Conclusion: Our results suggest that the TGF-beta 1/MIR21 signaling pathway may be involved in the suppressive effects of L. acidophilus on inflammation caused by S. typhimurium in intestinal Caco-2 cells.
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