Rab27A promotes cellular apoptosis and ROS production by regulating the miRNA-124-3p/STAT3/RelA signalling pathway in ulcerative colitis
JOURNAL OF CELLULAR AND MOLECULAR MEDICINE
Authors: Luo, Yang; Yu, Min-Hao; Yan, Ya-Ru; Zhou, Yong; Qin, Shao-Lan; Huang, Yi-Zhou; Qin, Jun; Zhong, Ming
Abstract
Ulcerative colitis (UC) is a multifactorial inflammatory disease, and increasing evidence has demonstrated that the mechanism of UC pathogenesis is associated with excessive cellular apoptosis and reactive oxygen species (ROS) production. However, their function and molecular mechanisms related to UC remain unknown. In this study, Rab27A mRNA and protein were proven to be overexpressed in intestinal epithelial cells of UC patients and DSS-induced colitis mice, compared with control (P < 0.05). And Rab27A silencing inhibits inflammatory process in DSS-induced colitis mice (P < 0.05). Then, it was shown that knockdown of Rab27A suppressed apoptosis and ROS production through modulation of miR-124-3p, whereas overexpression of Rab27A promoted apoptosis and ROS production in LPS-induced colonic cells. In addition, enhanced expression of miR-124-3p attenuated apoptosis and ROS production by targeting regulation of STAT3 in LPS-induced colonic cells. Mechanistically, we found Rab27A reduced the expression and activity of miR-124-3p to activate STAT3/RelA signalling pathway and promote apoptosis and ROS production in LPS-induced colonic cells, whereas overexpression of miR-124-3p abrogated these effects of Rab27A. More importantly, animal experiments illustrated that ectopic expression of Rab27A promoted the inflammatory process, whereas overexpression of miR-124-3p might interfere with the inflammatory effect in DSS-induced colitis mice. In summary, Rab27A might modulate the miR-124-3p/STAT3/RelA axis to promote apoptosis and ROS production in inflammatory colonic cells, suggesting that Rab27A as a novel therapeutic target for the prevention and treatment of UC patients.
Sirtuin 1 activation alleviates primary biliary cholangitis via the blocking of the NF-kappa B signaling pathway
INTERNATIONAL IMMUNOPHARMACOLOGY
Authors: Li, Yong; Xi, Yanhai; Tao, Guohua; Xu, Guohua; Yang, Zaixing; Fu, Xingli; Liang, Yan; Qian, Jianping; Cui, Yanhong; Jiang, Tingwang
Abstract
This report sought to establish the mechanistic role of sirtuin-1 (Sirt1), a NAD(+)-dependent deacetylase in the modulation of primary biliary cholangitis (PBC) pathogenesis. 64 PBC patients (diagnosed based on practice guidelines for American Association for the Study of Liver Diseases) and 60 healthy controls were included in this study. Clinically, the mRNA expression level of Sirt1 in macrophages differentiated from peripheral blood mononuclear cells (PBMCs) of PBC subjects substantially decreased when compared with the healthy controls but not in other Sirt family genes (Sirt2-7). Consistent with clinical results, a PBC murine model showed that levels of Sirt1 significantly decreased in the liver and Kupffer cells of mice treated with polyinosinic/polycytidylic acid (poly I:C) for 16 weeks. A TAK1 inhibitor (NG25) prevented the poly I:C-induced Sirt1 protein level decreasing in Kupffer cells but not MAPK inhibitor. Sirt1 activators resveratrol (RSV) and SRT1720 (SRT) ameliorated poly I:C-induced hepatic injury observed via histopathologic analysis and decreased aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in the PBC murine model. Furthermore, Sirt1 activators significantly reduced pro-inflammatory cytokines levels such as interleukin-1 beta (IL-1 beta), IL-6, interferon-gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) in serum in poly I:C-induced mice. In addition, Sirt1 activators significantly inhibited the phosphorylated and acetylated levels of the RelA/p65 subunit of the nuclear transcription factor (NF-kappa B) but not the interferon regulatory factor (IRF) 3 in poly I:C-injured mice livers. Significantly, RSV improved the interaction between Sirt1 and p65, which may contribute to the decreased activity of NF-kappa B. In summary, the Sirt1 signaling pathway plays an essential role in the development of PBC and this may represent a novel approach and target for the treatment of PBC.