miR-125b promotes the NF-κB-mediated inflammatory response in NAFLD via directly targeting TNFAIP3.
Zhang Qian,Yu Kun,Cao Yazhen,Luo Yanli,Liu Yan,Zhao Caiyan
Life sciences
BACKGROUND:Non-alcoholic fatty liver disease (NAFLD) has a high incidence and mortality rate, and a rapid course of clinical development. Although miR-125b is closely associated with the pathogenesis of liver fibrosis and hepatocellular carcinoma, the role of miR-125b in NAFLD remains unknown. METHODS:The levels of TNF-α, IL-6, and IL-1β expression were examined via ELISA assays. Real-time PCR was used to determine the levels of miR-125b and tumor necrosis factor alpha-induced protein 3 (TNFAIP3) expression. The related molecular mechanisms were examined by performing luciferase reporter, western blot, and immunofluorescence assays. Structural changes in the livers of mice with NAFLD were observed via H&E staining. RESULTS:The levels of TNF-α, IL-6, and IL-1β in NAFLD patients were greatly increased, and miR-125b expression was significantly up-regulated. The phosphorylation of IκBα and p65, and secretion of inflammatory factors were all markedly decreased by miR-125b silencing, but greatly increased by miR-125b overexpression. We also demonstrated that downregulation of TNFAIP3 in NAFLD was negatively correlated with miR-125b. Interestingly, the influence of miR-125b inhibitors on nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)-mediated inflammatory responses were greatly aggravated by co-treatment with TNFAIP siRNA; however, the opposite results were obtained after treatment with miR-125b mimics and TNFAIP plasmids. Furthermore, the HF-induced liver damage and inflammatory responses were greatly ameliorated by miR-125b inhibitors but further aggravated by co-treatment with TNFAIP3 siRNA. CONCLUSION:MiR-125b promoted the NF-κB-mediated inflammatory response in NAFLD by directly targeting TNFAIP3, and that mechanism might be target for treating NAFLD.
10.1016/j.lfs.2021.119071
TNFAIP3 ameliorates the degeneration of inflammatory human nucleus pulposus cells by inhibiting mTOR signaling and promoting autophagy.
Chen Jie,Ma Yufei,Yang Zhijie,Lan Haiyang,Liu Guangliang,Zhang Ye,Xia Huiqiang,Wang Xiaofang,Han Fei,Tu Xiaolin,Liu Bo
Aging
Autophagy is involved in degenerative diseases such as osteoarthritis and disc degeneration. Although, tumor necrosis factor α-induced protein 3 (TNFAIP3) is well-known as a key regulator of inflammation and autophagy, it is still not clear whether TNFAIP3 regulates autophagy to protect from human disc cells degeneration. We hypothesize that TNFAIP3 may also regulate autophagy to inhibit pro-inflammatory cytokines expression in human nucleus pulposus cells (NPCs). In this study, TNFAIP3 expression was increased in degenerative disc tissue as well as LPS-stimulated human NPCs, and the effect of TNFAIP3 in LPS-induced NPCs was further explored. The results demonstrated that pro-inflammatory cytokines expression in TNFAIP3-His cells was decreased, while it was increased in TNFAIP3-siRNA cells. Further molecular mechanism research showed that TNFAIP3-siRNA cells enhanced the phosphorylation of mammalian target of rapamycin (mTOR) and inhibited autophagy. Meanwhile, after treatment of TNFAIP3-siRNA cells with the mTOR inhibitor Torin1, the level of autophagy increased and the decrease of extracellular matrix was reversed. In summary, overexpressed TNFAIP3 can promote autophagy and reduce inflammation in LPS-induced human NPCs. Moreover, autophagy triggered by TNFAIP3 can ameliorate the degeneration of inflammatory human NPCs, providing a potential and an attractive therapeutic strategy for degenerative disease.
10.18632/aging.104160
The anti-inflammatory protein TNFAIP3/A20 binds the WD40 domain of ATG16L1 to control the autophagic response, NFKB/NF-κB activation and intestinal homeostasis.
Serramito-Gómez Inmaculada,Boada-Romero Emilio,Slowicka Karolina,Vereecke Lars,Van Loo Geert,Pimentel-Muiños Felipe X
Autophagy
The C-terminal domain of ATG16L1 includes 7 WD40-type repeats (WD40 domain, WDD) and is not required for canonical macroautophagy/autophagy. Instead, the WDD allows ATG16L1 to induce LC3/Atg8 lipidation in single-membrane compartments, although a detailed functional characterization of this region is still missing. In a recent report we identify the anti-inflammatory molecule TNFAIP3/A20 as a binding partner of the WDD. Such physical interaction allows mutual downregulation of the expression levels of both proteins, so that the absence of one of them causes upregulation of the other. This cross-regulation provides a molecular basis for a striking genetic interaction in mice where elimination of both molecules in the intestinal epithelium generates an aggressive inflammatory phenotype. studies reveal unexpected features of the functional interplay between ATG16L1 and TNFAIP3. ATG16L1 requires TNFAIP3 to sustain the canonical autophagic flux measured by SQSTM1/p62 degradation. The WDD mediates lysosomal degradation of TNFAIP3 promoted by ATG16L1, and also regulates the NFKB/NF-κB response. Therefore, our data reveal new roles of the WDD and TNFAIP3 in the regulation of autophagy, protein stability and inflammatory signaling. More generally, we identify the interaction between ATG16L1 and TNFAIP3 as a signaling hub that integrates different pathways with important implications for intestinal homeostasis.
10.1080/15548627.2019.1628549
A20 Attenuates Liver Fibrosis in NAFLD and Inhibits Inflammation Responses.
Wang Xiaohan,Ai Luoyan,Xu Qingqing,Wu Changwei,Chen Zhiwei,Su Dazhi,Jiang Xiaoke,Fan Zhuping
Inflammation
We previously reported A20 was able to inhibit lipid accumulation in nonalcoholic steatohepatitis. We want to investigate whether A20 influences liver fibrosis in this study. Liver tissues from patients with hepatic fibrosis (n = 9) and healthy individuals (n = 7) were studied for A20 protein level by immunohistochemistry. A20 messenger RNA (mRNA) and protein level were also analyzed in two murine hepatic fibrosis models: methionine- and choline-deficient (MCD) diet and extrahepatic bile duct ligation (BDL) operation by real-time PCR and western blot. In vitro, the LX-2 human hepatic stellate cell line was treated by LPS at 0, 0.001, 0.01, 0.1, and 1 μg/mL for 6 h or at the concentration of 0.1 μg/mL for 0, 6, 12, and 24 h, then A20 expression levels were detected by western blot and PCR. The mRNA level of α-SMA, collagen I, collagen III, TGF-β, IL-6, MCP-1, and TLR4 was also examined by PCR. We then overexpressed A20 in LX-2 cells using adenovirus technique. Levels of α-SMA, collagen I, collagen III, TGF-β, IL-6, MCP-1, and TLR4 were examined in A20-overexpression LX-2 cells. Patients with hepatic fibrosis showed significantly higher A20 protein level compared with healthy controls. A20 mRNA and protein levels were also increased in livers from MCD feeding or BDL operation mice in comparison to normal controls. In LX-2 cells, LPS induced A20 protein in a concentration-dependent manner. The mRNA levels of α-SMA, collagen I, collagen III, TGF-β, IL-6, MCP-1, and TLR4 were increased after LPS treatment. Overexpression of A20 in LX-2 cells inhibited α-SMA deposition and collagen I, collagen III secretion. TGF-β, IL-6, MCP-1, and TLR4 mRNA levels were also reduced in A20-overexpression LX-2 cells in response to LPS stimulation. A20 overexpression inhibits hepatic stellate cell activation, which could be the mechanism for high A20 expression protected livers from fibrosis. Enhancement of A20 expression seems to be rational therapeutic strategies for liver fibrosis.
10.1007/s10753-017-0528-2
The deubiquitinating enzyme TNFAIP3 mediates inactivation of hepatic ASK1 and ameliorates nonalcoholic steatohepatitis.
Zhang Peng,Wang Pi-Xiao,Zhao Ling-Ping,Zhang Xin,Ji Yan-Xiao,Zhang Xiao-Jing,Fang Chun,Lu Yue-Xin,Yang Xia,Gao Mao-Mao,Zhang Yan,Tian Song,Zhu Xue-Yong,Gong Jun,Ma Xin-Liang,Li Feng,Wang Zhihua,Huang Zan,She Zhi-Gang,Li Hongliang
Nature medicine
Activation of apoptosis signal-regulating kinase 1 (ASK1) in hepatocytes is a key process in the progression of nonalcoholic steatohepatitis (NASH) and a promising target for treatment of the condition. However, the mechanism underlying ASK1 activation is still unclear, and thus the endogenous regulators of this kinase remain open to be exploited as potential therapeutic targets. In screening for proteins that interact with ASK1 in the context of NASH, we identified the deubiquitinase tumor necrosis factor alpha-induced protein 3 (TNFAIP3) as a key endogenous suppressor of ASK1 activation, and we found that TNFAIP3 directly interacts with and deubiquitinates ASK1 in hepatocytes. Hepatocyte-specific ablation of Tnfaip3 exacerbated nonalcoholic fatty liver disease- and NASH-related phenotypes in mice, including glucose metabolism disorders, lipid accumulation and enhanced inflammation, in an ASK1-dependent manner. In contrast, transgenic or adeno-associated virus-mediated TNFAIP3 gene delivery in the liver in both mouse and nonhuman primate models of NASH substantially blocked the onset and progression of the disease. These results implicate TNFAIP3 as a functionally important endogenous suppressor of ASK1 hyperactivation in the pathogenesis of NASH and identify it as a potential new molecular target for NASH therapy.
10.1038/nm.4453