SNX10 mediates alcohol-induced liver injury and steatosis by regulating the activation of chaperone-mediated autophagy.

BACKGROUND & AIMS: Alcoholic liver disease (ALD) is a major cause of morbidity and mortality worldwide. However, the cellular defense mechanisms underlying ALD are not well understood. Recent studies highlighted the involvement of chaperone-mediated autophagy (CMA) in regulating hepatic lipid metabolism. Sorting nexin (SNX)-10 has a regulatory function in endolysosomal trafficking and stabilisation. Here, we investigated the roles of SNX10 in CMA activation and in the pathogenesis of alcohol-induced liver injury and steatosis. METHODS: Snx10 knockout (Snx10 KO) mice and their wild-type (WT) littermates fed either the Lieber-DeCarli liquid alcohol diet or a control liquid diet, and primary cultured WT and Snx10 KO hepatocytes stimulated with ethanol, were used as in vivo and in vitro ALD models, respectively. Activation of CMA, liver injury parameters, inflammatory cytokines, oxidative stress and lipid metabolism were measured. RESULTS: Compared with WT littermates, Snx10 KO mice exhibited a significant amelioration in ethanol-induced liver injury and hepatic steatosis. Both in vivo and in vitro studies showed that SNX10 deficiency upregulated lysosome-associated membrane protein type 2A (LAMP-2A) expression and CMA activation, which could be reversed by SNX10 overexpression in vitro. LAMP-2A interference confirmed that the upregulation of Nrf2 and AMPK signalling pathways induced by SNX10 deficiency relied on CMA activation. Pull-down assays revealed an interaction between SNX10 and cathepsin A (CTSA), a key enzyme involved in LAMP-2A degradation. Deficiency in SNX10 inhibited CTSA maturation and increased the stability of LAMP-2A, resulting in an increase in CMA activity. CONCLUSIONS: SNX10 controls CMA activity by mediating CTSA maturation, and, thus, has an essential role in alcohol-induced liver injury and steatosis. Our results provide evidence for SNX10 as a potential promising therapeutic target for preventing or ameliorating liver injury in ALD. LAY SUMMARY: Alcoholic liver disease is a major cause of morbidity and mortality worldwide. Recent studies highlight the involvement of chaperone-mediated autophagy (CMA) in regulating hepatic lipid metabolism. Our study reveals that deficiency of sorting nexin (SNX) 10 increases the stability of LAMP-2A by inhibiting cathepsin A maturation, resulting in the increase of CMA activity and, thus, alleviates alcohol-induced liver injury and steatosis.

Protective effects of Wang-Bi tablet on bone destruction in collagen-induced arthritis by regulating osteoclast-osteoblast functions.

ETHNOPHARMACOLOGICAL RELEVANCE: Wang-bi tablet (WB) consists of 17 traditional Chinese medicines and has been used for treating rheumatoid arthritis (RA) in China for many years, however, its pharmacologic mechanism is not clear. AIM OF STUDY: The aim of this study was to investigate the therapeutic effect of WB on collagen-induced mouse arthritis and explored the underlying mechanism. MATERIALS AND METHODS: DBA/1 mice were used to establish a type II collagen-induced arthritis (CIA) model. From the day of arthritis onset, mice were treated daily by gavage with either total glucosides of paeony (TGP, 0.37  g/kg/d) or WB at a lower (1.11  g/kg/d, WBL) or higher dose of (3.33  g/kg/d, WBH) for 8 weeks. The severity of arthritis, levels of cytokines and the activation of signaling pathways were determined. RESULTS: Our results revealed that WB treatment effectively alleviated inflammatory symptoms and prevented bone erosions and joint destructions. It obviously decreased the serum concentration of pro-inflammatory cytokines TNF-α, IL-6 and IL-17α, while increased the concentration of anti-inflammatory cytokine IL-10. Interestingly, the proportion of splenic Treg cells were increased significantly. In vitro experiments showed that WB inhibited the differentiation of osteoclasts. Consistently, the mRNA levels of tartrate-resistant acid phosphatase (TRAP) and cathepsin K (CtsK), and the activation of NF-κB and JAK-STAT3 signaling pathways in the paws of CIA mice were inhibited by WB treatment. On the other hand, up-regulation of osteogenic genes Runx2, Osterix mRNA, and activation of Wnt/ß-catenin signaling pathway along with a decreased receptor activator of nuclear factor κB ligand (RANKL) expression were found in WB treated mice. CONCLUSION: Our results suggest that the therapeutic effect of Wang-bi tablet could be attributed to its inhibitory activity on NF-κB and STAT3 signaling pathway-mediated osteoclast differentiation, and its enhancement on Wnt/ß-catenin signaling pathway-mediated osteoblast functions.

Protective effects of a traditional Chinese herbal formula Jiang-Xian HuGan on Concanavalin A-induced mouse hepatitis via NF-κB and Nrf2 signaling pathways.

ETHNOPHARMACOLOGICAL RELEVANCE: Jiang-Xian HuGan (JXHG) formulated by five natural products including Freshwater clam (Corbicula fluminea), Curcuma longa L., Ligustrum lucidum, Eclipta prostrata (L.) L. and Paeonia lactiflora Pall., has exhibited a great hepatoprotective effect. AIM OF THIS STUDY: We investigated the effect of JXHG on concanavalin A (ConA)-induced acute live injury in mice, and to elucidate its underlying molecular mechanisms. MATERIALS AND METHODS: Jiangkanling Capsule (900 mg/kg), low-dose JXHG (LJXHG, 700 mg/kg), high-dose JXHG (HJXHG, 1400 mg/kg) were administered to mice by oral gavage daily for 20 days prior to a single intravenous injection of ConA (20 mg/kg). Liver injury was evaluated by measuring the serum levels of enzymes and cytokines as well as liver histological analysis. We also measured the hepatic expression of cytokines at mRNA levels and the proteins related to NF-κB and Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) signaling pathways. RESULT: Our results showed that JXHG pretreatment significantly alleviated ConA-induced live injury as evidenced by decreased serum levels of glutamic-pyruvic transaminase (ALT) and glutamic oxalacetic transaminase (AST), and reduced hepatocyte apoptosis and mortality. Furthermore, JXHG was able to significantly reduce the serum levels of proinflammatory cytokines, down-regulate the mRNA expression of interleukin-6 (IL-6) and interferon-γ (IFN-γ), and up-regulate IL-10 as well as superoxide-dimutase-1 (SOD1), glutathione reductase (GSR) and Glutathione peroxidase 2 (GPX2) mRNA in the liver tissues after Con A injection. In addition, JXHG pretreatment dramatically suppressed the phosphorylation of NF-κB p65 (p65), increased Nrf2 expression, and decreased the expression ratio of cleaved caspase-3/caspase-3 in liver tissues. CONCLUSION: These results suggest that JXHG protects against ConA-induced acute live injury through inhibiting NF-κB mediated inflammatory pathway and promoting Nrf2 mediated anti-oxidative stress signaling pathway.

Suppressive effects of Wang­Bi Tablet on adjuvant­induced arthritis in rats via NF­κB and STAT3 signaling pathways.

Rheumatoid arthritis (RA) severely affects the quality life of patients due to its high association with disability. Traditional Chinese medicines have been reported to exert notable therapeutic effects on RA. The Chinese medicinal prescription Wang­Bi Tablet (WB) has been successfully used to clinically treat RA for many years; however, its pharmacological mechanism of action is largely unclear. In the present study, adjuvant­induced arthritis (AIA) rats were used to evaluate the anti­inflammatory effects of WB and western blotting was used to explore the molecular mechanisms. The experimental results demonstrated that WB treatment significantly reduced arthritis score and hind­paw volume. Furthermore, synovial hyperplasia, inflammatory cell infiltration and joint destruction were ameliorated by WB. The expression levels of the proinflammatory cytokines interleukin (IL)­1ß, tumor necrosis factor­α and IL­6, were reduced in the joints of WB­treated rats. Western blotting revealed that WB could also inhibit excessive activation of nuclear factor (NF)­κB and Janus kinase (JAK)­signal transducer and activator of transcription 3 (STAT3) signaling pathways. These results indicated that the therapeutic effects of WB on AIA may be accomplished through inhibition of the NF­κB and JAK­STAT3 signaling pathways. These findings provide experimental evidence to support WB as a therapeutic agent for the treatment of patients with RA.