Inhibition of NLRP3-mediated crosstalk between hepatocytes and liver macrophages by geniposidic acid alleviates cholestatic liver inflammatory injury

PPARα agonist ameliorates cholestatic liver injury by regulating hepatic macrophage homeostasis

Inflammatory response plays an essential role in the pathogenesis of cholestatic liver injury. PPARα agonists have been shown to regulate bile acid homeostasis and hepatic inflammation. However, the immunoregulatory mechanisms through which PPARα agonists ameliorate cholestatic liver injury remain unclear. In this study, surgical bile duct ligation was performed to establish a mouse model of cholestasis. Our study revealed that PPARα agonist alleviated cholestatic liver injury in mice by suppressing inflammatory response, reducing neutrophil infiltration, and promoting M2-like macrophage polarization. CyTOF analysis showed that PPARα agonist increased the proportion of anti-inflammatory F4/80hiCD44+MHCII- M2-like macrophages while decreasing the proportion of pro-inflammatory CD64+CX3CR1+CCR2hiVISTAhiCD172a+CD44hi M1-like MoMFs. Additionally, scRNA-seq indicated that PPARα agonist regulated the developmental trajectory and homeostasis of hepatic macrophages. Mechanistically, PPARα agonist may influence the expression of immune regulators in heterogeneous macrophages to exert protective effects against cholestasis. In addition, the CCL and MIF signaling pathways may participate in the communication among hepatic immune cells, including macrophages, neutrophils, natural killer cells, and dendritic cells, in response to the PPARα agonist. In conclusions, PPARα agonist alleviated cholestatic liver injury by attenuating the inflammatory response and restoring hepatic macrophage homeostasis. This study might enhance the understanding of the immunoregulatory mechanisms of PPARα agonists, providing promising therapeutic targets for cholestatic liver diseases.

Redox-Responsive AIEgen Diselenide-Covalent Organic Framework Composites Targeting Hepatic Macrophages for Treatment of Drug-induced Liver Injury

The escalating misuse of antipyretic and analgesic drugs, alongside the rising incidents of acute drug-induced liver injury, underscores the need for a precisely targeted drug delivery system. Herein, two isoreticular covalent organic frameworks (Se-COF and Se-BCOF) are developed by Schiff-base condensation of emissive tetraphenylethylene and diselenide-bridged monomers. Leveraging the specific affinity of macrophages for mannose, the first precise targeting of these COFs to liver macrophages is achieved. The correlation is also explored between the therapeutic effects of COFs and the NLRP3/ASC/Caspase-1 signaling pathway. Utilizing this innovative delivery vehicle, the synergistic delivery of matrine and berberine are accomplished, compounds extracted from traditional Chinese medicine. This approach not only demonstrated the synergistic effects of the drugs but also mitigated their toxicity. Notably, berberine, through phosphorylation of JNK and up-regulation of nuclear Nrf-2 and its downstream gene Mn-SOD expression, simultaneously countered excessive ROS and suppressed the activation of the NLRP3/ASC/Caspase-1 signaling pathway in injured liver tissues. This multifaceted approach proved highly effective in safeguarding against acute drug-induced liver injury, ultimately restoring liver health to normalcy. These findings present a novel and promising strategy for the treatment of acute drug-induced liver injury.

Geniposidic Acid Attenuates Chronic Tubulointerstitial Nephropathy Through Regulation of the NF-ƙB/Nrf2 Pathway Via Aryl Hydrocarbon Receptor Signaling

Renal fibrosis is an outcome of chronic kidney disease, independent of the underlying etiology. Renal fibrosis is caused primarily by oxidative stress and inflammation. We identified the components of Plantaginis semen and elucidated their anti-fibrotic and anti-inflammatory mechanisms. The renoprotective components and underlying molecular mechanisms of P. semen were investigated in rats with adenine-induced chronic tubulointerstitial nephropathy (TIN) and in idole-3-acetic acid (IAA)-stimulated NRK-52E cells. Acetate and n-butanol extracts were found to be the bioactive fractions of P. semen. A total of 65 compounds including geniposidic acid (GPA), apigenin (APG), and acteoside (ATS) were isolated and identified. Among the seven main extract components, treatment with GPA, APG, and ATS reduced the serum levels of creatinine and urea in TIN rats. Mechanistically, GPA ameliorated renal fibrosis through repressing aryl hydrocarbon receptor (AHR) signaling and regulating redox signaling including inhibiting proinflammatory nuclear factor kappa B (NF-ƙB) and its target gene products as well as activated antioxidative nuclear factor-erythroid-2-related factor 2 (Nrf2) and its downstream target gene products in both TIN rats and IAA-stimulated NRK-52E cells. The inhibitory effect of GPA on AHR, NF-Ƙb, and Nrf2 signaling were partially abolished in IAA-stimulated NRK-52E cells treated with CH223191 compared with untreated IAA-stimulated NRK-52E cells. These data demonstrated that GPA alleviates oxidative stress and inflammation partly by suppressing AHR signaling.

Lupeol improves bile acid metabolism and metabolic dysfunction-associated steatotic liver disease in mice via FXR signaling pathway and gut-liver axis

Metabolic dysfunction-associated steatotic liver disease (MASLD) has a multifactorial and complex pathogenesis. Notably, the disorder of Bile acid (BA) metabolism and lipid metabolism-induced lipotoxicity are the main risk factors of MASLD. Lupeol, traditional regional medicine from Xinjiang, has a long history of use for its anti-inflammatory, anti-tumor, and immune-modulating properties. Recent research suggests its potential as a therapeutic option for MASLD due to its proposed binding capacity to the nuclear BA receptor, Farnesoid X receptor (FXR), hence could represent a therapeutic option for MASLD. In this study, a natural triterpenoid drug lupeol improved BA metabolism and MASLD in mice through the FXR signaling pathway and the gut-liver axis. Furthermore, lupeol effectively restored gut healthiness and improved intestinal immunity, barrier integrity, and inflammation, as indicated by the reconstructed gut flora. Compared with fenofibrate (Feno), lupeol treatment significantly reduced weight gain, fat deposition, and liver injury, decreased serum total cholesterol (TC) and triglyceride (TG) levels, and alleviated hepatic steatosis and liver inflammation. BA analysis showed that lupeol treatment accelerated BA efflux and decreased uptake of BA by increasing hepatic FXR and bile salt export pump (BSEP) expression. Gut microbiota alterations could be related to enhanced fecal BA excretion in lupeol-treated mice. Therefore, consumption of lupeol may prevent HFD-induced MASLD and BA accumulation, possibly via the FXR signaling pathway and regulating the gut microbiota.

Sarmentol H derived from Sedum sarmentosum Bunge directly targets FXR to mitigate cholestasis by recruiting SRC-1

BACKGROUND

Farnesoid X receptor (FXR) is a vital receptor for bile acids and plays an important role in the treatment of cholestatic liver disease. In addition to traditional bile acid-based steroidal agonists, synthetic alkaloids are the most commonly reported non-steroidal FXR agonists. Sarmentol H is a nor-sesquiterpenoid obtained from Sedum sarmentosum Bunge, and in vitro screening experiments have shown that it might be related to the regulation of the FXR pathway in a previous study.

PURPOSE

To investigate the therapeutic effects of sarmentol H on cholestasis and to determine whether sarmentol H directly targets FXR to mitigate cholestasis. Furthermore, this study aimed to explore the key amino acid residues involved in the binding of sarmentol H to FXR through site-directed mutagenesis.

METHODS

An intrahepatic cholestasis mouse model was established to investigate the therapeutic effects of sarmentol H on cholestasis. In vitro experiments, including Co-Ip and FXR-EcRE-Luc assays, were performed to assess whether sarmentol H activates FXR by recruiting the receptor coactivator SRC1. CETSA, SIP, DARTS, and ITC were used to determine the binding of sarmentol H to FXR protein. The key amino acid residues for sarmentol H binding to FXR were analyzed by molecular docking and site-directed mutagenesis. Finally, we conducted in vivo experiments on wild-type and Fxr-/- mice to further validate the anticholestatic target of sarmentol H.

RESULTS

Sarmentol H had significant ameliorative effects on the pathological conditions of cholestatic mice induced with ANIT. In vitro experiments suggested that it is capable of activating FXR and regulating downstream signaling pathways by recruiting SRC1. The target validation experiments showed that sarmentol H had the ability to bind to FXR as a ligand (KD = 2.55 μmol/L) and enhance the stability of its spatial structure. Moreover, site-directed mutagenesis revealed that THR292 and TYR365 were key binding sites for sarmentol H and FXR. Furthermore, knockout of the Fxr gene resulted in a significantly higher degree of ANIT-induced cholestatic liver injury than that in wild-type cholestatic mice, and the amelioration of cholestasis or regulatory effects on FXR downstream genes by sarmentol H also disappeared in Fxr-/- cholestatic mice.

CONCLUSION

Sarmentol H is an FXR agonist. This is the first study to show that it exerts a significant therapeutic effect on cholestatic mice, and can directly bind to FXR and activate it by recruiting the coactivator SRC1.

Optimized therapeutic potential of Yinchenhao decoction for cholestatic hepatitis by combined network meta-analysis and network pharmacology

BACKGROUND

Cholestatic hepatitis is recognized as a significant contributor to the development of liver fibrosis and cirrhosis. As a well-known classic formula for the treatment of cholestatic hepatitis, Yinchenhao decoction (YCHD) is widely used in countries in Asia, including China, Japan, and Korea. However, in recent years, a risk of liver injury has been reported from Rheum palmatum L. and Gardenia jasmonoides J.Ellis which are the main ingredients of YCHD. Therefore, the question arises whether YCHD is still safe enough for the treatment of cholestatic hepatitis or whether an optimized ratio of ingredients should be applied. These is inevitable questions for the clinical application of YCHD.

PURPOSE

To provide a scientific basis for the clinical application of YCHD through a combination of meta-analysis and network pharmacology and to find the best ratio of components to ensure optimal therapeutic efficacy and safety. At the same time, a deeper understanding of the mechanisms of YCHD was explored.

METHODS

We retrieved relevant trials from various databases including PubMed, Web of Science, EMBASE, Cochrane Library, China National Knowledge Infrastructure (CNKI), VIP and Wanfang databases up to August 2023. After screening for inclusion and exclusion criteria, we assessed efficiency, ALT, AST, and TBIL as outcome parameters. The relevant data underwent a network meta-analysis using STATA 16.0 software. Based on network pharmacology, we screened the disease targets, active ingredients, and targets related to YCHD. The targets were visualized using Cytoscape 3.9.1. Then, potential mechanisms were explored based on bioinformatic techniques.

RESULTS

Twenty eligible studies were finally screened and a total of 1,591 patients who fulfilled the inclusion criteria were enrolled in the study. The meta-analysis results indicated that TG-c (treatment group c) [(Artemisia capillaris Thunb. : Gardenia jasminoides J.Ellis : Rheum palmatum L. = 10:5:2-10:5:3) + CT] was the most promising therapeutic approach, demonstrating superior efficacy and notable improvements in both AST and TBIL levels. For ALT, TG-d [(Artemisia capillaris : Gardenia jasminoides : Rheum palmatum = 5:1:1-5:2:1) + CT] exhibited the greatest potential as optimal therapy option. Based on the surface under the cumulative ranking curve (SUCRA) values, TG-c was the best therapy in terms of efficiency and improvement in TBIL levels, while TG-d was the most effective in reducing ALT levels. For AST levels, TG-e [(Artemisia capillaris : Gardenia jasminoides : Rheum palmatum = 5:2:2-5:3:3) + CT] was the most effective therapy. The comprehensive analysis revealed that TG-c exhibited the most pronounced efficacy. Combined network pharmacology, GO enrichment analysis and KEGG pathway enrichment analysis displayed that the key target genes of Artemisia capillaris, Rheum palmatum, and Gardenia jasminoides were closely involved in inflammation response, bile transport, apoptosis, oxidative stress, and regulation of leukocyte migration. Notably, bile secretion dominated the common pathway of the three herbs. On the other hand, Artemisia capillaris exhibited a unique mode of action by regulating the IL-17 signaling pathway, which may play a crucial role in its effectiveness.

CONCLUSION

Based on our findings, the optimal TG-C demonstrated the most favorable overall therapeutic efficacy by increasing the dosage of Artemisia capillaris while reducing the dosage of Gardenia jasminoides and Rheum palmatum. This is attributed to the potent ability of Artemisia capillaris. to effectively modulate the IL-17 signaling pathway, thereby exerting a beneficial therapeutic effect. Conversely, Gardenia jasminoides and Rheum palmatum may potentially enhance the activation of the NF-кB signaling pathway, thereby elevating the risk of hepatotoxicity.

IRG1/itaconate alleviates acute liver injury in septic mice by suppressing NLRP3 expression and its mediated macrophage pyroptosis via regulation of the Nrf2 pathway

Sepsis, a systemic inflammatory response triggered by infection, has a considerably high mortality rate. However, effective prevention and intervention measures against sepsis remain insufficient. Therefore, this study aimed to investigate the mechanisms underlying the protective properties of immune response gene-1 (IRG1) and 4-Octyl itaconate (OI) during acute liver damage in mice with sepsis. A sepsis mouse model was established to compare wild-type and IRG1-/- groups. The impact of IRG1/Itaconate on pro- and anti-inflammatory cytokines was evaluated using J774A.1 cells. IRG1/Itaconate substantially reduced pro-inflammatory cytokines and increased the release of anti-inflammatory cytokines. It reduced pathological damage to liver tissues, preserved normal liver function, decreased the release of reactive oxygen species (ROS) and LDH, and enhanced the GSH/GSSG ratio. Moreover, IRG1 and itaconic acid activated the Nrf2 signaling pathway, regulating the expression of its downstream antioxidative stress-related proteins. Additionally, they inhibited the activity of NLRP3 inflammatory vesicles to suppress the expression of macrophage-associated pyroptosis signaling molecules. Our findings demonstrate that IRG1/OI inhibits NLRP3 inflammatory vesicle activation and macrophage pyroptosis by modulating the Nrf2 signaling pathway, thereby attenuating acute liver injury in mice with sepsis. These findings could facilitate the clinical application of IRG1/Itaconate to prevent sepsis-induced acute liver injury.

Timosaponin BⅡ reduces colonic inflammation and alleviates DSS-induced ulcerative colitis by inhibiting NLRP3

ETHNOPHARMACOLOGICAL RELEVANCE

The Timosaponin BⅡ (TBⅡ) is one of the main active components of the traditional Chinese medicine Anemarrhena asphodeloides, and it is a steroidal saponin with various pharmacological activities such as anti-oxidation, anti-inflammatory and anti-apoptosis. However, its role in acute ulcerative colitis remains unexplored thus far.

AIM OF THE STUDY

This study aims to investigate the protective effect of TBⅡ against dextran sulfate sodium (DSS)-induced ulcerative colitis in mice and elucidate its underlying mechanisms.

METHODS

Wild-type (WT) and NLRP3 knockout (NLRP3-/-) mice were applied to evaluate the protective effect of TBⅡ in DSS-induced mice colitis. Pharmacological inhibition of NLRP3 or adenovirus-mediated NLRP3 overexpression in bone marrow-derived macrophages (BMDM) from WT mice and colonic epithelial HCoEpiC cells was used to assess the role of TBⅡ in LPS + ATP-induced cell model. RNA-seq, ELISA, western blots, immunofluorescence staining, and expression analysis by qPCR were performed to examine the alterations of colonic NLRP3 expression in DSS-induced colon tissues and LPS + ATP-induced cells, respectively.

RESULTS

In mice with DSS-induced ulcerative colitis, TBⅡ treatment attenuated clinical symptoms, repaired the intestinal mucosal barrier, reduced inflammatory infiltration, and alleviated colonic inflammation. RNA-seq analysis and protein expression levels demonstrated that TBⅡ could prominently inhibit NLRP3 signaling. TBⅡ-mediated NLRP3 inhibition was associated with alleviating intestinal permeability and inflammatory response via the blockage of communication between epithelial cells and macrophages, probably in an NLRP3 inhibition mechanism. However, pharmacological inhibition of NLRP3 by MCC950 or Ad-NLRP3 mediated NLRP3 overexpression significantly impaired the TBⅡ-mediated anti-inflammatory effect. Mechanistically, TBⅡ-mediated NLRP3 inhibition may be partly associated with the suppression of NF-κB, a master pro-inflammatory factor for transcriptional regulation of NLRP3 expression in the priming step. Moreover, co-treatment TBⅡ with NF-κB inhibitor BAY11-7082 partly impaired TBⅡ-mediated NLRP3 inhibition, and consequently affected the IL-1β mature and secretion. Importantly, TBⅡ-mediated amelioration was not further enhanced in NLPR3-/- mice.

CONCLUSION

TBⅡ exerted a prominent protective effect against DSS-induced colitis via regulation of alleviation of intestinal permeability and inflammatory response via the blockage of crosstalk between epithelial cells and macrophages in an NLRP3-mediated inhibitory mechanism. These beneficial effects could make TBⅡ a promising drug for relieving colitis.

Geniposidic acid alleviates osteoarthritis progression through inhibiting inflammation and chondrocytes ferroptosis

Osteoarthritis is one of the common diseases that seriously affects the quality of life of middle-aged and elderly people worldwide. Geniposidic acid (GPA) is extracted from Eucommia ulmoides that exhibits various pharmacological effects. This study investigated the function of GPA on osteoarthritis (OA) in IL-1β-stimulated mouse chondrocytes and mouse OA model. Mouse OA model was established by destabilization of the medial meniscus (DMM) and GPA was given intraperitoneal injection. The results demonstrated that GPA could alleviate DMM-induced OA in mice. In vitro, IL-1β-induced PGE2, NO, MMP1 and MMP3 were suppressed by GPA. Furthermore, IL-1β-induced ferroptosis was inhibited by GPA, as confirmed by the inhibition of MDA, iron, and ROS, as well as the upregulation of GSH, GPX4, and Ferritin. In addition, GPA was found to increase the expression of Nrf2 and HO-1. And the inhibition of GPA on IL-1β-induced inflammation and ferroptosis were prevented by Nrf2 inhibitor. In conclusion, GPA alleviates OA progression through inhibiting inflammation and chondrocytes ferroptosis via Nrf2 signalling pathway.

Activated hepatic stellate cell-derived Bmp-1 induces liver fibrosis via mediating hepatocyte epithelial-mesenchymal transition

Liver fibrosis is a reparative response to injury that arises from various etiologies, characterized by activation of hepatic stellate cells (HSCs). Periostin, a secreted matricellular protein, has been reported to participate in tissue development and regeneration. However, its involvement in liver fibrosis remains unknown. This study investigated the roles and mechanisms of Periostin in phenotypic transition of HSCs and relevant abnormal cellular crosstalk during liver fibrosis. The fate of hepatic stellate cells (HSCs) during liver fibrogenesis was investigated using single-cell and bulk RNA sequencing profiles, which revealed a significant proliferation of activated HSCs (aHSCs) in fibrotic livers of both humans and mice. αSMA-TK mice were used to demonstrate that depletion of proliferative aHSCs attenuates liver fibrosis induced by carbon tetrachloride and 3,5-diethoxycarbonyl-1,4-dihydrocollidine. Through integrating data from single-cell and bulk sequencing, Periostin was identified as a distinctive hallmark of proliferative aHSC subpopulation. Elevated levels of Periostin were detected in fibrotic livers of both humans and mice, primarily within aHSCs. However, hepatic Periostin levels were decreased along with depletion of proliferative aHSCs. Deficiency of Periostin led to reduced liver fibrosis and suppressed hepatocyte epithelial-mesenchymal transition (EMT). Periostin-overexpressing HSCs, exhibiting a proliferative aHSC phenotype, release bone morphogenetic protein-1 (Bmp-1), which activates EGFR signaling, inducing hepatocyte EMT and contributing to liver fibrosis. In conclusion, Periostin in aHSCs drives their acquisition of a proliferative phenotype and the release of Bmp-1. Proliferative aHSC subpopulation-derived Bmp-1 induces hepatocyte EMT via EGFR signaling, promoting liver fibrogenesis. Bmp-1 and Periostin should be potential therapeutic targets for liver fibrosis.

Geniposidic acid attenuates DSS-induced colitis through inhibiting inflammation and regulating gut microbiota

Geniposidic acid (GPA) is a bioactive compound isolated from Gardenia jasminoides Ellis (Rubiaceae) that has long been used to treat arthritis, jaundice, and hypertension. However, the therapeutic effects of GPA against colitis remain underexplored. This study aimed to investigate the effect of GPA on the remission of colitis and the underlying mechanisms. A DSS-induced colitis mouse model was used to evaluate the influence of GPA on the modulation of gut microbiota and intestinal epithelial barrier function. Our results indicated that GPA improved DSS-induced mouse colitis, including loss of body weight, disease activity index (DAI), colon length, and colonic pathological damage. DSS-induced destruction of the intestinal barrier was also significantly repaired by GPA treatment. In addition, the relative levels of pro-inflammatory cytokines, such as IL-1β and TNF-α, were markedly alleviated by GPA. Furthermore, western blot analysis revealed that GPA downregulated the protein expression of the nuclear transcription factor NF-κB. Finally, we first demonstrated that GPA could alleviate gut microbiota dysbiosis in mice with colitis by bacterial 16S rRNA sequencing. In conclusion, our study demonstrates the therapeutic and protective effects of GPA on IBD and provides novel insights into the prevention of colitis by targeting gut microbiota metabolism using natural products.

Identification of pancreatic lipase inhibitors from Eucommia ulmoides tea by affinity-ultrafiltration combined UPLC-Orbitrap MS and in vitro validation

Pancreatic lipase inhibitors can reduce blood lipids by inactivating the catalytic activity of human pancreatic lipase, a key enzyme involved in triglyceride hydrolysis, which helps control some dyslipidemic diseases. The ability of Eucommia ulmoides tea to improve fat-related diseases is closely related to the natural inhibitory components of pancreatic lipase contained in the tea. In this study, fifteen pancreatic lipase inhibitors were screened and identified from Eucommia ulmoides tea by affinity-ultrafiltration combined UPLC-Q-Exactive Orbitrap/MS. Four representative components of geniposidic acid, quercetin-3-O-sambuboside, isochlorogenic acid A, and quercetin with high binding degrees were further verified by nanoscale differential scanning fluorimetry (nanoDSF) and enzyme inhibitory assays. The results of flow cytometry showed that they could significantly reduce the activity of pancreatic lipase in AR42J cells induced by palmitic acid in a concentration-dependent manner. Our findings suggest that Eucommia ulmoides tea may be a promising resource for pancreatic lipase inhibitors of natural origin.

Effects of various interventions on non-alcoholic fatty liver disease (NAFLD): A systematic review and network meta-analysis

Background: With the increasing prevalence of obesity and metabolic syndrome, the incidence of non-alcoholic fatty liver disease (NAFLD) is also increasing. In the next decade, NAFLD may become the main cause of liver transplantation. Therefore, the choice of treatment plan is particularly important. The purpose of this study was to compare several interventions in the treatment of NAFLD to provide some reference for clinicians in selecting treatment methods.

Methods: We searched Public Medicine (PubMed), Medline, Excerpta Medica Database (Embase), and Cochrane Library from January 2013 to January 2023 to identify randomized controlled trials (RCTs) published in English. The network meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Forty-three studies accounting for a total of 2,969 patients were included, and alanine aminotransferase (ALT), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL) were selected as outcome measures for analysis and comparison.

Results: We evaluated the results of drug, diet, and lifestyle interventions between the intervention and control groups. Curcumin (CUN) and probiotics (PTC) were selected for medication, the Mediterranean diet (MDED) was selected for special diet (SPD), and various kinds of exercise and lifestyle advice were selected for lifestyle interventions (LFT). The SUCRA was used to rank interventions according to the effect on ALT indicators (SUCRA: PTC 80.3%, SPD 65.2%, LFT 61.4%, PLB 32.8%, CUN 10.2%), TC indicators (SUCRA: PTC 89.4%, SPD 64%, CUN 34%, LFT 36.6%, PLB 17%), and LDL indicators (SUCRA: PTC 84.2%, CUN 69.5%, LFT 51.7%, PLB 30.1%, SPD 14.5%). The pairwise meta-analysis results showed that MDED was significantly better than NT in improving ALT [SMD 1.99, 95% CI (0.38, 3.60)]. In terms of improving TC and LDL, ATS was significantly better than NT [SMD 0.19, 95% CI (0.03, 0.36)] [SMD 0.18, 95% CI (0.01, 0.35)].

Conclusion: Our study showed that PTC is most likely to be the most effective treatment for improving NAFLD indicators. Professional advice on diet or exercise was more effective in treating NAFLD than no intervention.

Inflammasome and pyroptosis in autoimmune liver diseases

Autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), and IgG4-related sclerosing cholangitis (IgG4-SC) are the four main forms of autoimmune liver diseases (AILDs), which are all defined by an aberrant immune system attack on the liver. Most previous studies have shown that apoptosis and necrosis are the two major modes of hepatocyte death in AILDs. Recent studies have reported that inflammasome-mediated pyroptosis is critical for the inflammatory response and severity of liver injury in AILDs. This review summarizes our present understanding of inflammasome activation and function, as well as the connections among inflammasomes, pyroptosis, and AILDs, thus highlighting the shared features across the four disease models and gaps in our knowledge. In addition, we summarize the correlation among NLRP3 inflammasome activation in the liver-gut axis, liver injury, and intestinal barrier disruption in PBC and PSC. We summarize the differences in microbial and metabolic characteristics between PSC and IgG4-SC, and highlight the uniqueness of IgG4-SC. We explore the different roles of NLRP3 in acute and chronic cholestatic liver injury, as well as the complex and controversial crosstalk between various types of cell death in AILDs. We also discuss the most up-to-date developments in inflammasome- and pyroptosis-targeted medicines for autoimmune liver disorders.

Therapeutic interventions target the NLRP3 inflammasome in ulcerative colitis: Comprehensive study

One of the significant health issues in the world is the prevalence of ulcerative colitis (UC). UC is a chronic disorder that mainly affects the colon, beginning with the rectum, and can progress from asymptomatic mild inflammation to extensive inflammation of the entire colon. Understanding the underlying molecular mechanisms of UC pathogenesis emphasizes the need for innovative therapeutic approaches based on identifying molecular targets. Interestingly, in response to cellular injury, the NLR family pyrin domain containing 3 (NLRP3) inflammasome is a crucial part of the inflammation and immunological reaction by promoting caspase-1 activation and the release of interleukin-1β. This review discusses the mechanisms of NLRP3 inflammasome activation by various signals and its regulation and impact on UC.

Thioredoxin reductase 1 regulates hepatic inflammation and macrophage activation during acute cholestatic liver injury

BACKGROUND AND AIMS

Cholestatic liver diseases, including primary sclerosing cholangitis, are characterized by periportal inflammation with progression to hepatic fibrosis and ultimately cirrhosis. We recently reported that the thioredoxin antioxidant response is dysregulated during primary sclerosing cholangitis. The objective of this study was to examine the impact of genetic and pharmacological targeting of thioredoxin reductase 1 (TrxR1) on hepatic inflammation and liver injury during acute cholestatic injury.

APPROACH AND RESULTS

Primary mouse hepatocytes and intrahepatic macrophages were isolated from 3-day bile duct ligated (BDL) mice and controls. Using wildtype and mice with a liver-specific deletion of TrxR1 (TrxR1LKO), we analyzed the effect of inhibition or ablation of TrxR1 signaling on liver injury and inflammation. Immunohistochemical analysis of livers from BDL mice and human cholestatic patients revealed increased TrxR1 staining in periportal macrophages and hepatocytes surrounding fibrosis. qPCR analysis of primary hepatocytes and intrahepatic macrophages revealed increased TrxR1 mRNA expression following BDL. Compared with sham controls, BDL mice exhibited increased inflammation, necrosis, and increased mRNA expression of pro-inflammatory cytokines, fibrogenesis, the NLRP3 inflammatory complex, and increased activation of NFkB, all of which were ameliorated in TrxR1LKO mice. Importantly, following BDL, TrxR1LKO induced periportal hepatocyte expression of Nrf2-dependent antioxidant proteins and increased mRNA expression of basolateral bile acid transporters with reduced expression of bile acid synthesis genes. In the acute BDL model, the TrxR1 inhibitor auranofin (10 mg/kg/1 d preincubation, 3 d BDL) ameliorated BDL-dependent increases in Nlrp3, GsdmD, Il1β, and TNFα mRNA expression despite increasing serum alanine aminotransferase, aspartate aminotransferase, bile acids, and bilirubin.

CONCLUSIONS

These data implicate TrxR1-signaling as an important regulator of inflammation and bile acid homeostasis in cholestatic liver injury.