Effect of NLRC5 on activation and reversion of hepatic stellate cells by regulating the nuclear factor-κB signaling pathway

Abstract

BACKGROUND The formation of liver fibrosis is mainly caused by the activation of hepatic stellate cells (HSCs) and the imbalance of extracellular matrix (ECM) production and degradation. The treatment of liver fibrosis mainly includes removing the cause, inhibiting the activation of HSCs, and inhibiting inflammation. NOD-like receptor (NLR) family, caspase activation and recruitment domain (CARD) domain containing 5/NOD27/CLR16.1 (NLRC5) is a highly conserved member of the NLR family and is involved in inflammation and immune responses by regulating various signaling pathways such as nuclear factor-κB (NF-κB) signaling. It has been found that NLRC5 plays an important role in liver fibrosis, but its specific effect and possible mechanism remain to be fully elucidated. AIM To investigate the role of NLRC5 in the activation and reversion of HSCs induced with transforming growth factor-β (TGF-β) and MDI, and to explore its relationship with liver fibrosis. METHODS A total of 24 male C57BL/6 mice were randomly divided into three groups, including normal, fibrosis, and recovery groups. Twenty-four hours after a liver fibrosis and spontaneous reversion model was established, the mice were sacrificed and pathological examination of liver tissue was performed to observe the degree of liver fibrosis in each group. LX-2 cells were cultured in vitro and treated with TGF-β1 and MDI. Real-time quantitative PCR (qPCR) and Western blot were used to analyze the expression levels of NLRC5, α-smooth muscle actin (α-SMA), and collagen type I alpha1 (Col1a1) in each group. The activity of NF-κB in each group of cells transfected with NLRC5-siRNA was detected. RESULTS Compared with the normal mice, the expression level of NLRC5 increased significantly ( P < 0.01) in the fibrosis group, but decreased significantly in the recovery group ( P < 0.01). In in vitro experiments, the content of NLRC5 was enhanced after TGF-β1 stimulation and decreased to a lower level when treated with MDI ( P < 0.01). The expression of α-SMA and Col1a1 proteins and mRNAs in TGF-β1-mediated cells was suppressed by transfection with NLRC5-siRNA ( P < 0.01). Western blot analysis showed that the expression of NF-κB p65 protein and phosphorylated IκBα (p-IκBα) was increased in the liver of mice in the fibrosis group but decreased in the recovery group ( P < 0.01), and the protein level of nuclear p65 and p-IκBα was significantly increased after treatment with NLRC5-siRNA ( P < 0.01). CONCLUSION NLRC5 may play a key role in the development and reversal of hepatic fibrosis through the NF-κB signaling pathway, and it is expected to be one of the clinical therapeutic targets.

Effects of G-Rh2 on mast cell-mediated anaphylaxis via AKT-Nrf2/NF-κB and MAPK-Nrf2/NF-κB pathways

“…In addition, NF-κB-p65 is also involved in mast cell activation [ 48 ]. Thus, we further clarified the effect of G-Rh2 on NF-κB-p65.…”

Teleost NOD-like receptors and their downstream signaling pathways: A brief review

“…The role of NLRC5 in antiviral signaling is further validated in primary human fibroblasts and several cell lines in which NLRC5 gene knockout showed significant decreased levels of IFN-a/b in response to virus [ 154 , 155 ]. Besides, NLRC5 has been shown to regulate NF-κB and IFN-I signaling pathways both positively [156] as well as negatively [ 53 , 157 ]. It also modulates other signaling pathways such as JAK2/STAT3 [158] , AKT/VEGF-A [159] , PI3K/AKT [160] , and inflammasome activity [161] ( Figure 4 ).…”

Network Pharmacology, Molecular Docking, Molecular Dynamics Simulation, and in vitro Experiments to Explore the Mechanism of Asiatic Acid Inhibiting Acetaldehyde-Induced Activation of Hepatic Stellate Cells

“…The NF-κB signaling pathway is closely associated with the development and reversal of liver fibrosis. 51 The present study found that NF-κB was significantly involved in the pro-fibrotic effect on HSCs, with NF-κB activation triggering the downregulation of the TGF-β pseudoreceptor BAMBI, enhancing TGF-β signaling and cell activation. 52 TGF-β is regarded as the main cytokine responsible for HSCs activation and proliferation, inducing HSCs to produce type I collagen and other components of the ECM, thus promoting the development of liver fibrosis.…”