FXR Inhibits Endoplasmic Reticulum Stress-Induced NLRP3 Inflammasome in Hepatocytes and Ameliorates Liver Injury

Unfolded protein response-activated NLRP3 inflammasome contributes to pyroptotic and apoptotic podocyte injury in diabetic kidney disease via the CHOP-TXNIP axis

BACKGROUND

Diabetic kidney disease (DKD) is the leading cause of chronic kidney disease and end-stage renal disease worldwide. Podocyte injury and death is a key event in DKD progression. Emerging evidence has indicated that crosstalk between unfolded protein response (UPR) and NLR family pyrin domain containing 3 (NLRP3) inflammasome plays an essential role in DKD progression. However, the involvement of these pathways in podocyte injury and death during DKD remains unclear.

RESULTS

Here, we found that inositol-requiring enzyme 1 (IRE1) and protein kinase RNA-like ER kinase (PERK) branches of the UPR, NLRP3 inflammasome, and apoptosis were activated in podocytes under DKD and high glucose (HG) conditions. In vitro, inducing ER stress by thapsigargin, and IRE1 or PERK overexpression upon HG treatment stimulated NLRP3 inflammasome-mediated pyroptosis and apoptosis, whereas inhibiting IRE1 or PERK suppressed them. Importantly, we discovered that the newly identified NLRP3-binding partner, thioredoxin-interacting protein (TXNIP), upon activation by the transcription factor (TF) PERK/CCAAT-enhancer-binding protein homologous protein (CHOP), served as a link between IRE1 or PERK branches with NLRP3 inflammasome-mediated pyroptosis and apoptosis. TXNIP expression was promoted in podocytes from DKD patients and db/db mice, as well as in HG-exposed conditionally immortalized human podocyte (HPC). In HG-exposed HPC, IRE1 or PERK overexpression upregulated TXNIP expression, while IRE1 or PERK inhibition downregulated it. TXNIP or CHOP silencing both inhibited HG-upregulated TXNIP, further blocking NLRP3 inflammasome-mediated pyroptosis and apoptosis. Furthermore, NLRP3 overexpression aggravated HG-induced pyroptosis and apoptosis, whereas additional TXNIP silencing reversed them without affecting IRE1 or PERK branches.

CONCLUSION

In conclusion, our results suggested that UPR/NLRP3 inflammasome-mediated pyroptosis/apoptosis pathway was involved in diabetic podocyte injury, and that targeting the CHOP-TXNIP axis may serve as a promising therapeutic target for DKD.

Heat stress enhances the expression of METTL3 to mediate N6-methyladenosine modification of SOS2 and NLRP3 inflammasome activation in boar Sertoli cells

Heat stress negatively affects pig production by disrupting the immune homeostasis of Sertoli cells (SCs), which compromises sperm quality, culminating in male infertility. Herein, we aimed to study the mechanism by which the NLRP3 inflammasome is activated by heat stress through N6-methyladenosine (m6A) modification regulation in SCs. Initially, it was found that heat stress (44°C, 30 min) markedly activated ERK1/2 signaling, which subsequently promoted NLRP3 inflammasome activation and inflammatory cytokine release from SCs. Then, using an m6A dot-blot assay, m6A sequencing, and methylated RNA immunoprecipitation, we found that heat stress augmented the level of m6A modification in SCs, and METTL3 augmented the m6A modification of mRNA encoding SOS Ras/Rho guanine nucleotide exchange factor 2 (SOS2), a key activator of the ERK pathway. Furthermore, YTHDF1 recognized and bound to the m6A-modified SOS2 mRNA to enhance its translation efficiency, ultimately triggering ERK1/2 signaling activation. In vivo experiments demonstrated that heat stress-induced decline in semen quality in mice was associated with elevated levels of m6A modifications in the testis and NLRP3 inflammasome activation. However, the damage caused by heat stress could be attenuated by intraperitoneal injection of S-Adenosylhomocysteine (SAH), a specific methyltransferase inhibitor. Our results emphasize the critical roles of m6A in regulating NLRP3 inflammasome activation under heat stress, identifying a novel therapeutic avenue to address heat stress.

Anti-inflammatory effects of Esomeprazole in septic lung injury by mediating endoplasmic reticulum stress

Acute lung injury characterized by overactive pulmonary inflammation is a common and serious complication of sepsis. Esomeprazole (ESO), a potent proton pump inhibitor (PPI), has been demonstrated as a promising anti-inflammatory agent in treating sepsis at high concentrations, the efficacy of which in sepsis-induced lung injury has not been explored. This research aimed to investigate the role of ESO in septic lung injury and the potential mechanism. The mice were pretreated by ESO prior to the construction of cecal ligation and puncture (CLP) sepsis model. MH-S lung macrophages were exposed to lipopolysaccharide (LPS) to induce inflammatory injury. The severity of lung damage was detected by H&E staining, measurement of lactic dehydrogenase (LDH) and lung wet/dry weight (W/D) ratio. The levels of inflammatory cytokines were detected by ELISA and Western blotting. The number of inflammatory cells was counted. Macrophage distribution was measured by immunohistochemical staining of macrophage markers. Western blotting also determined the expression of endoplasmic reticulum stress (ERS) and NLR family pyrin domain containing 3 (NLRP3) inflammasome-related proteins. CCK-8 method was used to detect cell viability. ESO concentration-dependently mitigated the pathological damage of lung tissues, reduced LDH activity, lung W/D ratio, decreased inflammatory cell counts and F4/80 expression in the lung tissues of sepsis mice. Besides, ESO suppressed inflammatory response, NLRP3 inflammasome activation and inactivated activating transcription factor 6 (ATF6)-CCAAT-enhancer-binding protein homologous protein (CHOP)-mediated ERS signaling both in vitro and in vivo. ATF6 overexpression partially reversed the impacts of ESO on NLRP3 inflammasome and the levels of inflammatory cytokines in LPS-induced MH-S cells. Anyway, ESO may inhibit ATF6/CHOP pathway to protect against inflammation in septic lung injury.

Endoplasmic reticulum stress in liver fibrosis: Mechanisms and therapeutic potential

This paper reviews the important role of endoplasmic reticulum stress in the patho mechanism of liver fibrosis and its potential as a potential target for the treatment of liver fibrosis. Liver fibrosis is the result of sustained inflammation and injury to the liver due to a variety of factors, triggering excessive deposition of extracellular matrix and fibrous scar formation, which in turn leads to loss of liver function and a variety of related complications. Endoplasmic reticulum stress is one of the characteristics of chronic liver disease and is closely related to the pathological process of chronic liver disease, including alcohol-related liver disease, viral hepatitis, and liver fibrosis. The unfolded protein response is one of the important response mechanisms to endoplasmic reticulum stress. It is associated with several pathological aspects of liver fibrosis and the maintenance of endoplasmic reticulum homeostasis. Interventions targeting endoplasmic reticulum stress for the treatment of liver fibrosis have potential research and application value. An in-depth understanding of the biological basis of endoplasmic reticulum stress is also needed in the treatment of liver fibrosis, as well as the development of more effective drugs and interventions to accurately regulate the endoplasmic reticulum signaling network, to achieve the restoration and maintenance of endoplasmic reticulum homeostasis at the cellular and organ levels, and to further promote the reversal of the pathological process of liver fibrosis.

Exogenous hydrogen sulfide improves non-alcoholic fatty liver disease by inhibiting endoplasmic reticulum stress/NLRP3 inflammasome pathway

Non-alcoholic fatty liver disease (NAFLD) is a common chronic liver disease worldwide, and its exact pathogenesis has not been fully studied. Hydrogen sulfide (H2S) is the third gas signaling molecule discovered in mammals, following nitric oxide and carbon monoxide. It has the effects of anti-inflammation, anti-apoptosis, and so on, thereby playing an important role in many diseases. However, the role and mechanism of exogenous H2S in NAFLD are not fully understood. In this study, we constructed in vitro and in vivo NAFLD models by feeding mice a high-fat diet and stimulating hepatocytes with palmitic acid, respectively, to investigate the improvement effect and mechanism of exogenous H2S on NAFLD. The results showed that NaHS (a donor of H2S) treatment alleviated lipid accumulation, inflammation, apoptosis and pyroptosis, and downregulated endoplasmic reticulum (ER) stress and nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NRRP3) inflammasome in NAFLD. The activation of NLRP3 inflammasome weakened NaHS improvement of NAFLD, indicating that exogenous H2S ameliorated NAFLD by inhibiting NLRP3 inflammasome-mediated lipid synthesis, inflammation, apoptosis and pyroptosis. Similarly, the activation of ER stress weakened NaHS improvement of NAFLD and NaHS inhibition of NLRP3 inflammasome, indicating that exogenous H2S suppressed NLRP3 inflammasome by downregulating ER stress, thus improving NAFLD. Additionally, the protein expressions of NLRP3 and cleaved caspase-1 were downregulated after inhibiting the reactive oxygen species (ROS)/extracellular signal-regulated kinases (ERK) and ROS/thioredoxin-interacting protein (TXNIP) pathways, indicating that ER stress activated NLRP3 inflammasome through the ROS/ERK and ROS/TXNIP pathways. In conclusion, our results indicated that exogenous H2S inhibited NLRP3 inflammasome-mediated hepatocytes inflammation, lipid synthesis, apoptosis and pyroptosis by downregulating ER stress, thereby improving NAFLD; Furthermore, ER stress activated NLRP3 inflammasome through the ROS/ERK and ROS/TXNIP pathways in NAFLD. ER stress/NLRP3 inflammasome is expected to become a new target of H2S for treating NAFLD.

Dual role of pyroptosis in liver diseases: mechanisms, implications, and therapeutic perspectives

Pyroptosis, a form of programmed cell death induced by inflammasome with a mechanism distinct from that of apoptosis, occurs via one of the three pathway types: classical, non-classical, and granzyme A/B-dependent pyroptosis pathways. Pyroptosis is implicated in various diseases, notably exhibiting a dual role in liver diseases. It facilitates the clearance of damaged hepatocytes, preventing secondary injury, and triggers immune responses to eliminate pathogens and damaged cells. Conversely, excessive pyroptosis intensifies inflammatory responses, exacerbates hepatocyte damage and promotes the activation and proliferation of hepatic stellate cells, accelerating liver fibrosis. Furthermore, by sustaining an inflammatory state, impacts the survival and proliferation of cancer cells. This review comprehensively summarizes the dual role of pyroptosis in liver diseases and its therapeutic strategies, offering new theoretical foundations and practical guidance for preventing and treating of liver diseases.

Tenascin C-Guided Nanosystem for Precision Delivery of Obeticholic Acid in Liver Fibrosis Therapy

Objective: Liver fibrosis, a hallmark of chronic liver diseases, is characterized by excessive extracellular matrix (ECM) deposition and scar tissue formation. Current antifibrotic nanomedicines face significant limitations, including poor penetration into fibrotic tissue, rapid clearance, and suboptimal therapeutic efficacy. The dense fibrotic ECM acts as a major physiological barrier, necessitating the development of a targeted delivery strategy to achieve effective therapeutic outcomes. Methods: We designed a liposomal delivery system functionalized with the GBI-10 aptamer and encapsulating obeticholic acid (OCA lips@Apt) to enhance selective delivery to fibrotic liver tissue while minimizing systemic toxicity. Results: Both in vitro and in vivo studies demonstrated that the aptamer-modified OCA liposomes effectively treated hepatic fibrosis through dual mechanisms: modulation of abnormal bile acid metabolism and attenuation of inflammation. The targeted delivery system leveraged the overexpression of Tenascin-C (TnC), a key ECM component in fibrotic tissues, for precise localization and enhanced endocytosis via the exposed cationic liposome surface. Conclusions: The OCA lips@Apt nanodrug demonstrated superior therapeutic efficacy with minimal off-target effects, offering a promising strategy to overcome critical barriers in liver fibrosis treatment. By precisely targeting the fibrotic ECM and modulating key pathological pathways, this TnC-guided liposomal delivery system provides a significant advancement in antifibrotic nanomedicine.

Mechanism of action of the nucleotide-binding oligomerization domain-like receptor protein 3 inflammasome and its regulation in liver injury

ABSTRACT

Nucleotide-binding oligomerization domain (NOD)-like receptor protein 3 (NLRP3) is a cytosolic pattern recognition receptor that recognizes multiple pathogen-associated molecular patterns and damage-associated molecular patterns. It is a cytoplasmic immune factor that responds to cellular stress signals, and it is usually activated after infection or inflammation, forming an NLRP3 inflammasome to protect the body. Aberrant NLRP3 inflammasome activation is reportedly associated with some inflammatory diseases and metabolic diseases. Recently, there have been mounting indications that NLRP3 inflammasomes play an important role in liver injuries caused by a variety of diseases, specifically hepatic ischemia/reperfusion injury, hepatitis, and liver failure. Herein, we summarize new research pertaining to NLRP3 inflammasomes in hepatic injury, hepatitis, and liver failure. The review addresses the potential mechanisms of action of the NLRP3 inflammasome, and its regulation in these liver diseases.

Comparison of Endoplasmic Reticulum Stress and Pyroptosis Induced by Pathogenic Calcium Oxalate Monohydrate and Physiologic Calcium Oxalate Dihydrate Crystals in HK-2 Cells: Insights into Kidney Stone Formation

Endoplasmic reticulum stress (ERS) can activate pyroptosis through CHOP and TXNIP; however, the correlation between this process and the formation of kidney stones has not been reported. The purpose is to investigate the effects of calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) on ERS and pyroptosis in HK-2 cells and to explore the formation mechanism of calcium oxalate stones. HK-2 cells were injured by 3 μm COM and COD. COM and COD significantly upregulated the expression levels of GRP78, CHOP, TXNIP, and pyroptosis-related proteins (NLRP3, caspase-1, GSDMD-N, and IL-1β). Fluorescence colocalization revealed that COM induced pyroptosis by inducing the interaction between TXNIP and NLRP3. Both COM and COD crystals can induce ERS and pyroptosis in HK-2 cells. COM induces the interaction with NLRP3 by the upregulation of CHOP and TXNIP and then promotes pyroptosis, while COD only promotes pyroptosis by the upregulation of CHOP. The cytotoxicity and the ability of COM to promote crystal adhesion and aggregation are higher than COD, suggesting that COM is more dangerous for calcium oxalate kidney stone formation.

Metabolic disorders, inter-organ crosstalk, and inflammation in the progression of metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a global health concern, affecting over 30 % of adults. It is a principal driver in the development of cirrhosis and hepatocellular carcinoma. The complex pathogenesis of MASLD involves an excessive accumulation of lipids, subsequently disrupting lipid metabolism and prompting inflammation within the liver. This review synthesizes the recent research progress in understanding the mechanisms contributing to MASLD progression, with particular emphasis on metabolic disorders and interorgan crosstalk. We highlight the molecular mechanisms linked to these factors and explore their potential as novel targets for pharmacological intervention. The insights gleaned from this article have important implications for both the prevention and therapeutic management of MASLD.

Regulation of bile acids and their receptor FXR in metabolic diseases

High sugar, high-fat diets and unhealthy lifestyles have led to an epidemic of obesity and obesity-related metabolic diseases, seriously placing a huge burden on socio-economic development. A deeper understanding and elucidation of the specific molecular biological mechanisms underlying the onset and development of obesity has become a key to the treatment of metabolic diseases. Recent studies have shown that the changes of bile acid composition are closely linked to the development of metabolic diseases. Bile acids can not only emulsify lipids in the intestine and promote lipid absorption, but also act as signaling molecules that play an indispensable role in regulating bile acid homeostasis, energy expenditure, glucose and lipid metabolism, immunity. Disorders of bile acid metabolism are therefore important risk factors for metabolic diseases. The farnesol X receptor, a member of the nuclear receptor family, is abundantly expressed in liver and intestinal tissues. Bile acids act as endogenous ligands for the farnesol X receptor, and erroneous FXR signaling triggered by bile acid dysregulation contributes to metabolic diseases, including obesity, non-alcoholic fatty liver disease and diabetes. Activation of FXR signaling can reduce lipogenesis and inhibit gluconeogenesis to alleviate metabolic diseases. It has been found that intestinal FXR can regulate hepatic FXR in an organ-wide manner. The crosstalk between intestinal FXR and hepatic FXR provides a new idea for the treatment of metabolic diseases. This review focuses on the relationship between bile acids and metabolic diseases and the current research progress to provide a theoretical basis for further research and clinical applications.

Endoplasmic Reticulum Stress Induces ROS Production and Activates NLRP3 Inflammasome Via the PERK-CHOP Signaling Pathway in Dry Eye Disease

Purpose

The purpose of this study was to investigate the potential roles of endoplasmic reticulum (ER) stress in the development of dry eye disease (DED).

Methods

Single-cell RNA sequencing (scRNA-seq) data from the Gene Expression Omnibus (GEO) database, derived from corneal tissues of a dry eye mouse model, was processed using the Seurat R program. The results were validated using a scopolamine-induced dry eye mouse model and a hyperosmotic-induced cell model involving primary human corneal epithelial cells (HCECs) and immortalized human corneal epithelial (HCE-2) cells. The HCE-2 cells were treated with 4-phenylbutyric acid (4-PBA) or tunicamycin (TM) to modulate ER stress. TXNIP and PERK knockdown were performed by siRNA transfection. Immunofluorescence, Western blotting, and real-time PCR were used to assess oxidative stress, ER stress, unfolded protein response (UPR) marker proteins, and TXNIP/NLRP3 axis activation.

Results

The analysis of scRNAseq data shows an increase in the ER stress marker GRP78, and the activation of the PERK-CHOP of UPR in DED mouse. These findings were confirmed both in vivo and in vitro. Additionally, HCE-2 cells treated with 4-PBA or TM showed significant effects on the production of reactive oxygen species (ROS) and the activation of the TXNIP/NLRP3-IL1β signaling pathway. Furthermore, siRNA knockdown of PERK or TXNIP, which alleviated the TXNIP/NLRP3-IL1β signaling axis, showed protective effects on HCECs.

Conclusions

This study explores the role of ER stress-induced oxidative stress and NLRP3-IL-1β mediated inflammation in DED, and highlights the therapeutic potential of PERK-CHOP axis and TXNIP in the treatment of DED.

Endothelial Dysfunction and Liver Cirrhosis: Unraveling of a Complex Relationship

Endothelial dysfunction (ED) is the in the background of multiple metabolic diseases and a key process in liver disease progression and cirrhosis decompensation. ED affects liver sinusoidal endothelial cells (LSECs) in response to different damaging agents, causing their progressive dedifferentiation, unavoidably associated with an increase in intrahepatic resistance that leads to portal hypertension and hyperdynamic circulation with increased cardiac output and low peripheral artery resistance. These changes are driven by a continuous interplay between different hepatic cell types, invariably leading to increased reactive oxygen species (ROS) formation, increased release of pro-inflammatory cytokines and chemokines, and reduced nitric oxide (NO) bioavailability, with a subsequent loss of proper vascular tone regulation and fibrosis development. ED evaluation is often accomplished by serum markers and the flow-mediated dilation (FMD) measurement of the brachial artery to assess its NO-dependent response to shear stress, which usually decreases in ED. In the context of liver cirrhosis, the ED assessment could help understand the complex hemodynamic changes occurring in the early and late stages of the disease. However, the instauration of a hyperdynamic state and the different NO bioavailability in intrahepatic and systemic circulation-often defined as the NO paradox-must be considered confounding factors during FMD analysis. The primary purpose of this review is to describe the main features of ED and highlight the key findings of the dynamic and intriguing relationship between ED and liver disease. We will also focus on the significance of FMD evaluation in this setting, pointing out its key role as a therapeutic target in the never-ending battle against liver cirrhosis progression.

The Molecular Mechanism of Farnesoid X Receptor Alleviating Glucose Intolerance in Turbot (Scophthalmus maximus)

To explore the molecular targets for regulating glucose metabolism in carnivorous fish, the turbot (Scophthalmus maximus) was selected as the research object to study. Farnesoid X receptor (FXR; NR1H4), as a ligand-activated transcription factor, plays an important role in glucose metabolism in mammals. However, the mechanisms controlling glucose metabolism mediated by FXR in fish are not understood. It was first found that the protein levels of FXR and its target gene, small heterodimer partner (SHP), were significantly decreased in the high-glucose group (50 mM, HG) compared with those in the normal glucose group (15 mM, CON) in primary hepatocytes of turbot. By further exploring the function of FXR in turbot, the full length of FXR in turbot was cloned, and its nuclear localization function was characterized by subcellular localization. The results revealed that the FXR had the highest expression in the liver, and its capability to activate SHP expression through heterodimer formation with retinoid X receptor (RXR) was proved, which proved RXR could bind to 15 binding sites of FXR by forming hydrogen bonds. Activation of FXR in both the CON and HG groups significantly increased the expression of glucokinase (gk) and pyruvate kinase (pk), while it decreased the expression of cytosolic phosphoenolpyruvate carboxykinase (cpepck), mitochondrial phosphoenolpyruvate carboxykinase (mpepck), glucose-6-phosphatase 1 (g6pase1) and glucose-6-phosphatase 2 (g6pase2), and caused no significant different in glycogen synthetase (gs). ELISA experiments further demonstrated that under the condition of high glucose with activated FXR, it could significantly decrease the activity of PEPCK and G6PASE in hepatocytes. In a dual-luciferase reporter assay, the FXR could significantly inhibit the activity of G6PASE2 and cPEPCK promoters by binding to the binding site 'ATGACCT'. Knockdown of SHP after activation of FXR reduced the inhibitory effect on gluconeogenesis. In summary, FXR can bind to the mpepck and g6pase2 promoters to inhibit their expression, thereby directly inhibiting the gluconeogenesis pathway. FXR can also indirectly inhibit the gluconeogenesis pathway by activating shp. These findings suggest the possibility of FXR as a molecular target to regulate glucose homeostasis in turbot.

trans-chalcone ameliorates CCl4-induced acute liver injury by suppressing endoplasmic reticulum stress, oxidative stress and inflammation

BACKGROUND

Acute liver injury serves as a crucial marker for detecting liver damage due to toxic, viral, metabolic, and autoimmune exposures. Due to the response to adverse external stimuli and various cellular homeostasis, Endoplasmic reticulum stress (ERS), Oxidative stress, and Inflammation have great potential for treating liver injury. Trans-chalcones (TC) is a polyphenolic compound derived from a natural plant with anti-oxidative and anti-inflammatory abilities. Here, TC was aimed to attenuate liver injury by triggering ER stress, oxidative stress, inflammation, and apoptosis. A single dose of carbon tetrachloride (CCl4) 1 mL/kg was administered intraperitoneally into C57BL6 mice to construct an in vivo NAFLD model, whereas AML12 cells were treated with lipopolysaccharides (LPS) to construct an in vitro NAFLD model. The mice used in the experiment were randomly assigned to two groups: a 12-hour set and a 24-hour set. Forty-nine mice were randomly divided into seven groups, the control group (Group I), TC group (Group II) 10 mg/kg TC, negative control group (Group III) CCl4, TC + CCl4 groups (Groups IV-VI), mice were subcutaneously treated with (5, 10, and 20) mg/kg of TC for three consecutive days before the CCl4 injection and the positive control group (Group VII) received 10 mg/kg Silymarin. After the experiment, serum transaminase, liver histological pathology, hepatic expression levels ERS, oxidative stress, and inflammation-related markers were assessed. TC pre-treatment significantly alleviates the expression of ER stress, oxidative stress, inflammatory cytokines, and apoptosis in both in vivo and in vitro models of liver injury. TC treatment significantly reduced serum transaminase levels (ALT and AST), and improved liver histopathological scores. TC administration also led to a reduction in MDA levels and the suppression of ROS generated by CCl4 in hepatic tissue, which contributed to an increase in GSH levels. The protective effect of TC on the liver injury mouse model was achieved by inhibiting hepatocyte apoptosis. Moreover, TC pre-treatment dramatically decreased the protein levels of ER stress indicators such as CHOP, Bip, Ero-Lα, IRE1α, PERK, Calnexin, and PDI when compared to the CCl4-only treated group. TC exerts hepatoprotective effects against CCl4-induced acute liver injuries in mice by modulating ERS, oxidative stress, and inflammation. These results suggest that TC pre-treatment at a dose of (20 mg/kg BW) was as effective as silymarin (10 mg/kg) in preventing CCl4-induced acute liver injury. Further investigations are necessary to elucidate the precise molecular mechanisms underlying the hepatoprotective effects of TC and to explore its therapeutic potential in clinical trials.

Methacrylated hyaluronic acid/laponite photosensitive, sustained-release hydrogel loaded with bilobalide for enhancing random flap survival through mitigation of endoplasmic reticulum stress

Random flaps are extensively utilized in plastic surgery due to their flexibility compared to traditional axial vascular system arrangements and their resemblance to injured skin in color, thickness, and texture. Despite these advantages, they are susceptible to ischemia-reperfusion injuries and subsequent necrosis post-transplantation. Bilobalide (BB), a sesquiterpene compound derived from Ginkgo biloba, exhibits notable antioxidant and anti-inflammatory properties and is commonly used to treat ischemiareperfusion injuries. However, its short half-life restricts its sustained efficacy in random flaps. In this study, we synthesized a multi-crosslinked, photosensitive methacryloyl hyaluronic acid(HAMA)/laponite(Lap)/bilobalide (BB) hydrogel. This dualcrosslinked hydrogel demonstrates superior mechanical properties and biocompatibility while providing a stable release of bilobalide. In vitro experiments showed that it significantly reduces edema, promotes angiogenesis, and enhances the survival of random flaps. Further network pharmacology analysis and recovery experiments suggested that the hydrogel's beneficial effects are mediated by the regulation of endoplasmic reticulum stress and specifically identified the regulation of the PERK/TXNIP/NLRP3 signaling pathway as crucial to its anti-inflammatory effects. Therefore, this HAMA/Lap/BB hydrogel promotes the survival of random flaps in rats by alleviating endoplasmic reticulum stress, providing a novel intervention strategy for the treatment of random flaps injuries.

SIRT5 safeguards against T-2 toxin induced liver injury by repressing iron accumulation, oxidative stress, and the activation of NLRP3 inflammasome

T-2 toxin, a highly toxic trichothecene mycotoxin widely found in food and feed, poses a significant threat to human health as well as livestock and poultry industry. Liver, being a crucial metabolic organ, is particularly susceptible to T-2 toxin induced damage characterized by inflammation and oxidative stress. Despite the role of Sirtuin 5 (SIRT5) in mitigating liver injury has been confirmed, its specific impact on T-2 toxin induced liver injury remains to be elucidated. The objective of this study was to investigate the protective role of SIRT5 against T-2 toxin induced liver injury in mice. Following the oral administration of 1 mg/kg.bw of T-2 toxin for 21 consecutive days to SIRT5 knockout (SIRT5-/-) and wild-type (WT) male mice, liver assessments were conducted. Our findings demonstrated that aggravated hepatic pathological injury was observed in SIRT5-/- mice, accompanied by elevated malondialdehyde (MDA) and Fe levels, as well as enhanced expression of glutathione peroxidase 4 (GPX4), NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3), apoptosis-associated speck-like protein containing a CARD (ASC), caspase-1, Gasdermin-D (GSDMD), tumour necrosis factor-alpha (TNF-α), and interleukin-1beta (IL-1β). These results indicated that SIRT5 alleviated hepatic structural damage and dysfunction, while inhibiting oxidative stress, iron accumulation, and NLRP3 inflammasome activation. Analysis revealed a positive correlation among NLRP3 inflammasome activation, iron accumulation, and oxidative stress. Overall, our study demonstrated that SIRT5 mitigated liver injury induced by T-2 toxin through inhibiting iron accumulation, oxidative stress, and NLRP3 inflammasome activation, providing novel insights into the management and prevention of T-2 toxin poisoning.

Tauroursodeoxycholic acid suppresses biliary epithelial cell apoptosis and endoplasmic reticulum stress by miR-107/NCK1 axis in a FXR-dependent manner

Tauroursodeoxycholic acid (TUDCA) can activate farnesoid X receptor (FXR) to involve in the formation of gallstones. Here, this study aimed to probe the potential mechanism of TUDCA-FXR network in the formation of bile duct stone. The levels of TUDCA, FXR and NCK1 were decreased, while the level of miR-107 was increased in the serum of bile duct stone patients. FXR expression was positively correlated with TUDCA or NCK1 expression in patients, moreover, TUDCA pretreatment in biliary epithelial cells increased the levels of FXR and NCK1, and rescued the decrease of NCK1 caused by FXR knockdown in cells. Then functional analysis showed FXR knockdown caused apoptosis and endoplasmic reticulum stress (ERS) as well as suppressed proliferation in biliary epithelial cells in vitro, which were attenuated by TUDCA pretreatment or NCK1 overexpression Mechanistically, NCK1 was a target of miR-107, which was up-regulated by FXR silencing, and FXR knockdown-induced decrease of NCK1 was rescued by miR-107 inhibition. Additionally, miR-107 expression was negatively correlated with TUDCA expression in bile duct stone patients, and TUDCA pretreatment in biliary epithelial cells decreased miR-107 expression by FXR. Functionally, the pretreatment of TUDCA or FXR agonist suppressed miR-107-evoked apoptosis and ERS in biliary epithelial cells. In conclusion, TUDCA up-regulates FXR expression to activate NCK1 through absorbing miR-107, thus suppressing the apoptosis and ERS in biliary epithelial cells, these results provided a theoretical basis for elucidating the mechanism of bile duct stone formation.

Adapting to change: resolving the dynamic and dual roles of NCK1 and NCK2

Adaptor proteins play central roles in the assembly of molecular complexes and co-ordinated activation of specific pathways. Through their modular domain structure, the NCK family of adaptor proteins (NCK1 and NCK2) link protein targets via their single SRC Homology (SH) 2 and three SH3 domains. Classically, their SH2 domain binds to phosphotyrosine motif-containing receptors (e.g. receptor tyrosine kinases), while their SH3 domains bind polyproline motif-containing cytoplasmic effectors. Due to these functions being established for both NCK1 and NCK2, their roles were inaccurately assumed to be redundant. However, in contrast with this previously held view, NCK1 and NCK2 now have a growing list of paralog-specific functions, which underscores the need to further explore their differences. Here we review current evidence detailing how these two paralogs are unique, including differences in their gene/protein regulation, binding partners and overall contributions to cellular functions. To help explain these contrasting characteristics, we then discuss SH2/SH3 structural features, disordered interdomain linker regions and post-translational modifications. Together, this review seeks to highlight the importance of distinguishing NCK1 and NCK2 in research and to pave the way for investigations into the origins of their interaction specificity.

Inhibiting endoplasmic reticulum stress alleviates perioperative neurocognitive disorders by reducing neuroinflammation mediated by NLRP3 inflammasome activation

AIM

The aim of this study is to explore the key mechanisms of perioperative neurocognitive dysfunction (PND) after anesthesia/surgery (A/S) by screening hub genes.

METHODS

Transcriptome sequencing was conducted on hippocampal samples obtained from 18-month-old C57BL/6 mice assigned to control (Ctrl) and A/S groups. The functionality of differentially expressed genes (DEGs) was investigated using Metascape. Hub genes associated with changes between the two groups were screened by combining weighted gene coexpression network analysis within CytoHubba. Reverse transcription PCR and western blotting were used to validate changes in mRNA and protein expression, respectively. NLRP3 inflammasome activation was detected by western blotting and ELISA. Tauroursodeoxycholic acid (TUDCA), an inhibitor of endoplasmic reticulum (ER) stress, was administrated preoperatively to explore its effects on the occurrence of PND. Immunofluorescence analysis was performed to evaluate the activation of astrocytes and microglia in the hippocampus, and hippocampus-dependent learning and memory were assessed using behavioral experiments.

RESULTS

In total, 521 DEGs were detected between the control and A/S groups. These DEGs were significantly enriched in biological processes related to metabolic processes and their regulation. Four hub genes (Hspa5, Igf1r, Sfpq, and Xbp1) were identified. Animal experiments have shown that mice in the A/S group exhibited cognitive impairments accompanied by increased Hspa5 and Xbp1 expression, ER stress, and activation of NLRP3 inflammasome.

CONCLUSIONS

Inhibiting ER stress alleviated cognitive impairment in A/S mice; particularly, ER stress induced by A/S results in NLRP3 inflammasome activation and neuroinflammation. Moreover, the preoperative administration of TUDCA inhibited ER stress, NLRP3 inflammasome activation, and neuroinflammation.

Endoplasmic reticulum stress in diseases

The endoplasmic reticulum (ER) is a key organelle in eukaryotic cells, responsible for a wide range of vital functions, including the modification, folding, and trafficking of proteins, as well as the biosynthesis of lipids and the maintenance of intracellular calcium homeostasis. A variety of factors can disrupt the function of the ER, leading to the aggregation of unfolded and misfolded proteins within its confines and the induction of ER stress. A conserved cascade of signaling events known as the unfolded protein response (UPR) has evolved to relieve the burden within the ER and restore ER homeostasis. However, these processes can culminate in cell death while ER stress is sustained over an extended period and at elevated levels. This review summarizes the potential role of ER stress and the UPR in determining cell fate and function in various diseases, including cardiovascular diseases, neurodegenerative diseases, metabolic diseases, autoimmune diseases, fibrotic diseases, viral infections, and cancer. It also puts forward that the manipulation of this intricate signaling pathway may represent a novel target for drug discovery and innovative therapeutic strategies in the context of human diseases.

Potential mechanisms of traditional Chinese medicine in the treatment of liver cirrhosis: a focus on gut microbiota

Cirrhosis, a pathological stage that develops from various chronic liver diseases, is characterized by liver fibrosis, pseudolobular formation, and chronic inflammation. When it progresses to the decompensated phase, the mortality rate of cirrhosis can reach 80%. The role of gut microbiota in the progression of liver diseases has received significant attention. Numerous studies have shown that regulating gut microbiota has significant therapeutic effects on preventing and reversing liver cirrhosis. This article reviewed the mechanisms by which gut microbiota influence liver cirrhosis, explaining the effective therapeutic effects of traditional Chinese medicine. Through multi-directional regulation involving signaling pathways, gut microbiota diversity, and restoration of intestinal barrier function, traditional Chinese medicine has been promising in ameliorating liver cirrhosis, providing treatment options and pharmacological guidance for the occurrence and development of liver cirrhosis.

DDIT3 aggravates TMJOA cartilage degradation via Nrf2/HO-1/NLRP3-mediated autophagy

OBJECTIVE

DNA damage-inducible transcript 3 (DDIT3), as a downstream transcription factor of endoplasmic reticulum stress, is reported to regulate chondrogenic differentiation under physiological and pathological state. However, the specific involvement of DDIT3 in the degradation of condylar cartilage of temporomandibular joint osteoarthritis (TMJOA) is unclarified.

DESIGN

The expression patterns of DDIT3 in condylar cartilage from monosodium iodoacetate-induced TMJOA mice were examined to uncover the potential role of DDIT3 in TMJOA. The Ddit3 knockout (Ddit3-/-) mice and their wildtype littermates (Ddit3+/+) were used to clarify the effect of DDIT3 on cartilage degradation. Primary condylar chondrocytes and ATDC5 cells were applied to explore the mechanisms of DDIT3 on autophagy and extracellular matrix (ECM) degradation in chondrocytes. The autophagy inhibitor chloroquine (CQ) was used to determine the effect of DDIT3-inhibited autophagy in vivo.

RESULTS

DDIT3 were highly expressed in condylar cartilage from TMJOA mice. Ddit3 knockout alleviated condylar cartilage degradation and subchondral bone loss, compared with their wildtype littermates. In vitro study demonstrated that DDIT3 exacerbated ECM degradation in chondrocytes induced by TNF-α through inhibiting autophagy. The intraperitoneal injection of CQ further confirmed that Ddit3 knockout alleviated cartilage degradation in TMJOA through activating autophagy in vivo.

CONCLUSIONS

Our findings identified the crucial role of DDIT3-inhibited autophagy in condylar cartilage degradation during the development of TMJOA.

Farnesoid X receptor: From Structure to Function and Its Pharmacology in Liver Fibrosis

The farnesoid X receptor (FXR), a ligand-activated transcription factor, plays a crucial role in regulating bile acid metabolism within the enterohepatic circulation. Beyond its involvement in metabolic disorders and immune imbalances affecting various tissues, FXR is implicated in microbiota modulation, gut-to-brain communication, and liver disease. The liver, as a pivotal metabolic and detoxification organ, is susceptible to damage from factors such as alcohol, viruses, drugs, and high-fat diets. Chronic or recurrent liver injury can culminate in liver fibrosis, which, if left untreated, may progress to cirrhosis and even liver cancer, posing significant health risks. However, therapeutic options for liver fibrosis remain limited in terms of FDA-approved drugs. Recent insights into the structure of FXR, coupled with animal and clinical investigations, have shed light on its potential pharmacological role in hepatic fibrosis. Progress has been achieved in both fundamental research and clinical applications. This review critically examines recent advancements in FXR research, highlighting challenges and potential mechanisms underlying its role in liver fibrosis treatment.

Luteolin, apigenin, and chrysin inhibit lipotoxicity-induced NLRP3 inflammasome activation and autophagy damage in macrophages by suppressing endoplasmic reticulum stress

Lipotoxicity leads to numerous metabolic disorders such as nonalcoholic steatohepatitis. Luteolin, apigenin, and chrysin are three flavones with known antioxidant and anti-inflammatory properties, but whether they inhibit lipotoxicity-mediated NLRP3 inflammasome activation was unclear. To address this question, we used J774A.1 macrophages and Kupffer cells stimulated with 100 μM palmitate (PA) in the presence or absence of 20 μM of each flavone. PA increased p-PERK, p-IRE1α, p-JNK1/2, CHOP, and TXNIP as well as p62 and LC3-II expression and induced autophagic flux damage. Caspase-1 activation and IL-1β release were also noted after 24 h of exposure to PA. In the presence of the PERK inhibitor GSK2656157, PA-induced CHOP and TXNIP expression and caspase-1 activation were mitigated. Compared with PA treatment alone, Bcl-2 coupled to beclin-1 was elevated and autophagy was reversed by the JNK inhibitor SP600125. With luteolin, apigenin, and chrysin treatment, PA-induced ROS production, ER stress, TXNIP expression, autophagic flux damage, and apoptosis were ameliorated. Moreover, TXNIP binding to NLRP3 and IL-1β release in response to LPS/PA challenge were reduced. These results suggest that luteolin, apigenin, and chrysin protect hepatic macrophages against PA-induced NLRP3 inflammasome activation and autophagy damage by attenuating endoplasmic reticulum stress.

Lactobacillus rhamnosus GG ameliorates triptolide-induced liver injury through modulation of the bile acid-FXR axis

Triptolide (TP) is the principal bioactive compound of Tripterygium wilfordii with significant anti-tumor, anti-inflammatory and immunosuppressive activities. However, its severe hepatotoxicity greatly limits its clinical use. The underlying mechanism of TP-induced liver damage is still poorly understood. Here, we estimate the role of the gut microbiota in TP hepatotoxicity and investigate the bile acid metabolism mechanisms involved. The results of the antibiotic cocktail (ABX) and fecal microbiota transplantation (FMT) experiment demonstrate the involvement of intestinal flora in TP hepatotoxicity. Moreover, TP treatment significantly perturbed gut microbial composition and reduced the relative abundances of Lactobacillus rhamnosus GG (LGG). Supplementation with LGG reversed TP-induced hepatotoxicity by increasing bile salt hydrolase (BSH) activity and reducing the increased conjugated bile acids (BA). LGG supplementation upregulates hepatic FXR expression and inhibits NLRP3 inflammasome activation in TP-treated mice. In summary, this study found that gut microbiota is involved in TP hepatotoxicity. LGG supplementation protects mice against TP-induced liver damage. The underlying mechanism was associated with the gut microbiota-BA-FXR axis. Therefore, LGG holds the potential to prevent and treat TP hepatotoxicity in the clinic.

New compatible pair of TCM: Paeoniae Radix Alba effectively alleviate Psoraleae Fructus-induced liver injury by suppressing NLRP3 inflammasome activation

Objective

Drug-induced liver injury (DILI), a type of acute inflammation, has sparked significant concern owing to its unpredictability and severity. Psoraleae Fructus (PF), an edible Chinese herb widely used in traditional Chinese medicine (TCM), causes liver injury. Therefore, the elucidation of the mechanism underlying PF-induced liver injury and the search for more effective means of detoxification using herbal compatibility has become an urgent issue. This study evaluated the hepatoprotective effects of Paeoniae Radix Alba (PRA), a hepatoprotective Chinese medicine, on PF-induced liver injury and explored the underlying mechanisms.

Methods

A rat model of lipopolysaccharide (LPS)-induced immune stress was established to evaluate the hepatotoxicity of PF and the detoxifying effect of PRA. Subsequently, inflammatory pathways were identified using network pharmacology. Finally, the molecular mechanism by which PRA alleviates PF-induced liver injury was validated using an inflammasome activation model in bone marrow-derived macrophages (BMDMs).

Results

In vivo, hepatocytes in rats treated with LPS + PF exhibited massive inflammatory infiltration and apoptosis, and the expression of liver injury indicators and inflammatory factors was significantly upregulated, which was reversed by PRA pretreatment. Network pharmacology showed that PRA alleviated PF-induced liver injury and was associated with the NOD-like receptor signaling pathway. Moreover, PF directly induced inflammasome activation in LPS-primed BMDMs which in turn induced caspase-1 activation and the secretion of downstream effector cytokines such as IL-1β. PRA pretreatment inhibited PF-induced activation of the NLRP3 inflammasome by mitigating the accumulation of mitochondrial reactive oxygen species (mtROS).

Conclusions

The present study demonstrates that PRA alleviated PF induced-liver injury by inhibiting NLRP3 inflammasome activation. The results of this study are expected to inform the prevention and control of PF-induced hepatotoxicity in clinical practice.

Targeting BRD4 mitigates hepatocellular lipotoxicity by suppressing the NLRP3 inflammasome activation and GSDMD-mediated hepatocyte pyroptosis

Nod-like receptor family pyrin-containing protein 3 (NLRP3) inflammasome plays a pathologic role in metabolic dysfunction-associated steatohepatitis (MASH), but the molecular mechanism regulating the NLRP3 inflammasome activation in hepatocellular lipotoxicity remains largely unknown. Bromodomain-containing protein 4 (BRD4) has emerged as a key epigenetic reader of acetylated lysine residues in enhancer regions that control the transcription of key genes. The aim of this study is to investigate if and how BRD4 regulated the NLRP3 inflammasome activation and pyroptosis in MASH. Using the AML12 and primary mouse hepatocytes stimulated by palmitic acid (PA) as an in vitro model of hepatocellular lipotoxicity, we found that targeting BRD4 by genetic knockdown or a selective BRD4 inhibitor MS417 protected against hepatosteatosis; and this protective effect was attributed to inhibiting the activation of NLRP3 inflammasome and reducing the expression of Caspase-1, gasdermin D (GSDMD), interleukin (IL)-1β and IL-6. Moreover, BRD4 inhibition limited the voltage-dependent anion channel-1 (VDAC1) expression and oligomerization in PA-treated AML12 hepatocytes, thereby suppressing the NLRP3 inflammasome activation. Additionally, the expression of BRD4 enhanced in MASH livers of humans. Mechanistically, BRD4 was upregulated during hepatocellular lipotoxicity that in turn modulated the active epigenetic mark H3K27ac at the promoter regions of the Vdac and Gsdmd genes, thereby enhancing the expression of VDAC and GSDMD. Altogether, our data provide novel insights into epigenetic mechanisms underlying BRD4 activating the NLRP3 inflammasome and promoting GSDMD-mediated pyroptosis in hepatocellular lipotoxicity. Thus, BRD4 might serve as a novel therapeutic target for the treatment of MASH.

Nr1h4 and Thrb ameliorate ER stress and provide protection in the MPTP mouse model of Parkinson's

Elevated ER stress has been linked to the pathogenesis of several disease conditions including neurodegeneration. In this study, we have holistically determined the differential expression of all the nuclear receptors (NRs) in the presence of classical ER stress inducers. Activation of Nr1h4 and Thrb by their cognate ligands (GW4064 and T3) ameliorates the tunicamycin (TM)-induced expression of ER stress genes. A combination of both ligands is effective in mitigating cell death induced by TM. Further exploration of their protective effects in the Parkinson's disease (PD) model shows that they reduce MPP+-induced dissipation of mitochondrial membrane potential and ROS generation in an in vitro PD model in neuronal cells. Furthermore, the generation of an experimental murine PD model reveals that simultaneous treatment of GW4064 and T3 protects mice from ER stress, dopaminergic cell death, and functional deficits in the MPTP mouse model of PD. Thus, activation of Nr1h4 and Thrb by their respective ligands plays an indispensable role in ER stress amelioration and mounts protective effects in the MPTP mouse model of PD.

Bile acids induce liver fibrosis through the NLRP3 inflammasome pathway and the mechanism of FXR inhibition of NLRP3 activation

BACKGROUND

Altered patterns of bile acids (BAs) are frequently present in liver fibrosis, and BAs function as signaling molecules to initiate inflammatory responses. Therefore, this study was conducted to uncover the notably altered components of BAs and to explore the pathway of altered BA induced inflammation in the development of liver fibrosis.

METHODS

Bile acids were quantified by ultraperformance liquid chromatography coupled to mass spectrometry (UPLC‒MS/MS). Cell Counting Kit-8 assays were used to determine the proliferative capacity of HSCs. Transwell assays and wound healing assays were used to determine the migratory capacity of LX2 cells. Protein expression was evaluated by western blotting.

RESULTS

Plasma bile acid analysis showed higher levels of GCDCA, TCDCA, GCA and TCA in patients with liver fibrosis than in normal controls. The AUC of GCDCA was the highest. Western blotting showed that GCDCA treatment increased the expression of NLRP3-related proteins and collagen1 in vitro and significantly increased LX2 cells proliferation and migration. Furthermore, knockdown of NLRP3 or overexpression of FXR in LX2 cells decreased the expression of the above proteins, and FXR inhibited NLRP3 (ser 295) phosphorylation in vitro and vivo. In vivo, HE, Masson's trichrome, and Sirius Red staining showed that GCDCA increased collagen fibers in the mouse liver, and the expression of NLRP3-related proteins, collagen 1, and α-SMA in the liver increased significantly. However, the knockout of NLRP3 reversed these patterns.

CONCLUSION

(1) Primary conjugated bile acids increased in patients with liver fibrosis; (2) GCDCA induce hepatic fibrosis via the NLRP3 inflammasome pathway; (3) FXR inhibits NLRP3 activity by restraining its phosphorylation; (4) knockdown or knockout of NLRP3 may relieve the onset of hepatic fibrosis.

Expression of hepatic genes involved in bile acid metabolism in dairy cows with fatty liver

Bile acids are cholesterol-derived molecules that are primarily produced in the liver. In nonruminants with fatty liver, overproduction of bile acids is associated with liver injury. During the transition period, fatty liver is a metabolic disorder that can affect up to 50% of high-producing dairy cows. The purpose of this study was to provide a comprehensive evaluation on hepatic bile acid metabolism in dairy cows with fatty liver by assessing expression changes of genes involved in bile acid synthesis, export and uptake. The serum activities of aspartate aminotransferase, alanine aminotransferase and glutamate dehydrogenase and concentration of total bile acids were all greater, whereas serum concentration of total cholesterol was lower in cows with fatty liver than in healthy cows. Content of total bile acids was higher but total cholesterol was slightly lower in liver tissues from fatty liver cows than from healthy cows. The hepatic mRNA abundance of cholesterol 7a-hydroxylase (CYP7A1), hydroxy-delta-5-steroid dehydrogenase, 3 β- and steroid delta-isomerase 7 (HSD3B7) and sterol 12α-hydroxylase (CYP8B1), enzymes involved in the classic pathway of bile acid synthesis, was higher in fatty liver cows than in healthy cows. Compared with healthy cows, the hepatic mRNA abundance of alternative bile acid synthesis pathway-related genes sterol 27-hydroxylase (CYP27A1) and oxysterol 7α-hydroxylase (CYP7B1) did not differ in cows with fatty liver. The protein and mRNA abundance of bile acid transporter bile salt efflux pump (BSEP) were lower in the liver of dairy cow with fatty liver. Compared with healthy cows, the hepatic mRNA abundance of bile acid transporters solute carrier family 51 subunit α (SLC51A), ATP binding cassette subfamily C member 1 (ABCC1) and 3 (ABCC3) was greater in cows with fatty liver, whereas the solute carrier family 51 subunit β (SLC51B) did not differ. The expression of genes involved in bile acid uptake, including solute carrier family 10 member 1 (NTCP), solute carrier organic anion transporter family member 1A2 (SLCO1A2) and 2B1 (SLCO2B1) was upregulated in dairy cows with fatty liver. Furthermore, the hepatic protein and mRNA abundance of bile acid metabolism regulators farnesoid X receptor (FXR) and small heterodimer partner (SHP) were lower in cows with fatty liver than in healthy cows. Overall, these data suggest that inhibition of FXR signaling pathway may lead to the increased bile acid synthesis and uptake and decreased secretion of bile acids from hepatocytes to the bile, which elevates hepatic bile acids content in dairy cows with fatty liver. As the hepatotoxicity of bile acids has been demonstrated on nonruminant hepatocytes, it is likely that the liver injury is induced by increased hepatic bile acids content in dairy cows with fatty liver.

Examining the Pathogenesis of MAFLD and the Medicinal Properties of Natural Products from a Metabolic Perspective

Metabolic-associated fatty liver disease (MAFLD), characterized primarily by hepatic steatosis, has become the most prevalent liver disease worldwide, affecting approximately two-fifths of the global population. The pathogenesis of MAFLD is extremely complex, and to date, there are no approved therapeutic drugs for clinical use. Considerable evidence indicates that various metabolic disorders play a pivotal role in the progression of MAFLD, including lipids, carbohydrates, amino acids, and micronutrients. In recent years, the medicinal properties of natural products have attracted widespread attention, and numerous studies have reported their efficacy in ameliorating metabolic disorders and subsequently alleviating MAFLD. This review aims to summarize the metabolic-associated pathological mechanisms of MAFLD, as well as the natural products that regulate metabolic pathways to alleviate MAFLD.

FXR controls duodenogastric reflux-induced gastric inflammation through negatively regulating ER stress-associated TNXIP/NLPR3 inflammasome

Duodenogastric reflux (DGR) is closely associated with gastric inflammation and tumorigenesis; however, the precise mechanism is unclear. Hence, we aim to clarify this molecular mechanism and design an effective therapeutic strategy based on it. The present study found that DGR induced TXNIP/NLRP3 inflammasome activation and triggered pyroptosis in gastric mucosa in vitro and in vivo, in which endoplasmic reticulum (ER) stress via PERK/eIF2α/CHOP signaling was involved. Mechanistically, farnesoid X receptor (FXR) antagonized the DGR-induced PERK/eIF2α/CHOP pathway and reduced TXNIP and NLRP3 expression. Moreover, FXR suppressed NLRP3 inflammasome activation by physically interacting with NLRP3 and caspase-1. Administration of the FXR agonist OCA protected the gastric mucosa from DGR-induced barrier disruption and mucosal inflammation. In conclusion, our study demonstrates the involvement of TXNIP/NLRP3 inflammasome-mediated pyroptosis in DGR-induced gastric inflammation. FXR antagonizes gastric barrier disruption and mucosal inflammation induced by DGR. Restoration of FXR activity may be a therapeutic strategy for DGR-associated gastric tumorigenesis.

Acute kidney injury: exploring endoplasmic reticulum stress-mediated cell death

Acute kidney injury (AKI) is a global health problem, given its substantial morbidity and mortality rates. A better understanding of the mechanisms and factors contributing to AKI has the potential to guide interventions aimed at mitigating the risk of AKI and its subsequent unfavorable outcomes. Endoplasmic reticulum stress (ERS) is an intrinsic protective mechanism against external stressors. ERS occurs when the endoplasmic reticulum (ER) cannot deal with accumulated misfolded proteins completely. Excess ERS can eventually cause pathological reactions, triggering various programmed cell death (autophagy, ferroptosis, apoptosis, pyroptosis). This article provides an overview of the latest research progress in deciphering the interaction between ERS and different programmed cell death. Additionally, the report consolidates insights into the roles of ERS in AKI and highlights the potential avenues for targeting ERS as a treatment direction toward for AKI.

Glycyrrhizin alleviates radiation-induced lung injury by regulating the NLRP3 inflammasome through endoplasmic reticulum stress

Objective

Radiation pneumonitis (RP) is the major adverse response of radiation therapy for thoracic malignant tumors, and there is a lack of effective interventions. The aim of this study was to investigate the radioprotective effect of Glycyrrhizin (GL) on RP and its potential mechanism.

Method

The body weight and lung weight of mice were monitored. HE staining was used to observe lung injury, and the expression of endoplasmic reticulum (ER) stress biomarkers and the activation of NLRP3 inflammasome were determined by Western blotting and immunohistochemistry. Flow cytometry was performed to check MLE-12 apoptosis. ER stress activator, Tunicamycin (Tuni), was used to verify the potential mechanism of GL. A systemic pharmacology explored the potential targets and pathways of GL.

Results

In this study, the lungs of irradiated mice showed significant pneumonic changes. In vivo and in vitro assay, NLRP3 inflammasome was significantly activated, the expression of ER stress biomarkers was elevated, flow cytometry confirms increased apoptosis in irradiated MLE-12 cells. GL inhibits the activation of NLRP3 inflammasome and ER stress pathways. Furthermore, systemic pharmacology revealed that the radioprotective effect of GL may be related to the MAPK signaling pathway.

Conclusion

In the present study, the results indicated that GL may regulate NLRP3 inflammasome through ER stress, thus exerting irradiation-protective effects on RP, and the ER stress pathway may be a potential target for RP treatment.

Hepatic Zbtb18 (Zinc Finger and BTB Domain Containing 18) alleviates hepatic steatohepatitis via FXR (Farnesoid X Receptor)

A lasting imbalance between fatty acid synthesis and consumption leads to non-alcoholic fatty liver disease (NAFLD), coupled with hepatitis and insulin resistance. Yet the details of the underlying mechanisms are not fully understood. Here, we unraveled that the expression of the transcription factor Zbtb18 is markedly decreased in the livers of both patients and murine models of NAFLD. Hepatic Zbtb18 knockout promoted NAFLD features like impaired energy expenditure and fatty acid oxidation (FAO), and induced insulin resistance. Conversely, hepatic Zbtb18 overexpression alleviated hepato-steatosis, insulin resistance, and hyperglycemia in mice fed on a high-fat diet (HFD) or in diabetic mice. Notably, in vitro and in vivo mechanistic studies revealed that Zbtb18 transcriptional activation of Farnesoid X receptor (FXR) mediated FAO and Clathrin Heavy Chain (CLTC) protein hinders NLRP3 inflammasome activity. This key mechanism by which hepatocyte's Zbtb18 expression alleviates NAFLD and consequent liver fibrosis was further verified by FXR's deletion and forced expression in mice and cultured mouse primary hepatocytes (MPHs). Moreover, CLTC deletion significantly abrogated the hepatic Zbtb18 overexpression-driven inhibition of NLRP3 inflammasome activity in macrophages. Altogether, Zbtb18 transcriptionally activates the FXR-mediated FAO and CLTC expression, which inhibits NLRP3 inflammasome's activity alleviating inflammatory stress and insulin resistance, representing an attractive remedy for hepatic steatosis and fibrosis.

Hepatitis B virus-mediated sodium influx contributes to hepatic inflammation via synergism with intrahepatic danger signals

The NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inflammasome has been involved in the pathogenesis of various chronic liver diseases. However, its role in hepatitis B virus (HBV)-associated hepatitis remains unknown. Here we demonstrate the synergistic effect of HBV with potential intrahepatic danger signals on NLRP3 inflammasome activation. HBV exposure at the appropriate temporal points enhances potassium efflux-dependent NLRP3 inflammasome activation in macrophages and also increases NLRP3 inflammasome-mediated inflammation in HBV-transgenic mouse model. HBV-mediated synergism with intrahepatic signals represented by ATP molecules on NLRP3 activation was observed via relevance analysis, confocal microscopy, and co-immunoprecipitation, and its effector cytokines exhibit positive associations with hepatic inflammation in patients with severe hepatitis B. Furthermore, the synergism of HBV on NLRP3 inflammasome activation owes to increased sodium influx into macrophages. Our data demonstrate that HBV contributes to hepatic inflammation via sodium influx-dependent synergistic activation of NLRP3 inflammasome, which provides a deeper understanding of immune pathogenesis in HBV-associated hepatitis.

Role of NLRP3 Inflammasome in Stroke Pathobiology: Current Therapeutic Avenues and Future Perspective

Neuroinflammation is a key pathophysiological feature of stroke-associated brain injury. A local innate immune response triggers neuroinflammation following a stroke via activating inflammasomes. The nucleotide-binding oligomerization domain leucine-rich repeat and pyrin domain-containing protein 3 (NLRP3) inflammasome has been heavily implicated in stroke pathobiology. Following a stroke, several stimuli have been suggested to trigger the assembly of the NLRP3 inflammasome. Recent studies have advanced the understanding and revealed several new players regulating NLRP3 inflammasome-mediated neuroinflammation. This article discussed recent advancements in NLRP3 assembly and highlighted stroke-induced mitochondrial dysfunction as a major checkpoint to regulating NLRP3 activation. The NLRP3 inflammasome activation leads to caspase-1-dependent maturation and release of IL-1β, IL-18, and gasdermin D. In addition, genetic or pharmacological inhibition of the NLRP3 inflammasome activation and downstream signaling has been shown to attenuate brain infarction and improve the neurological outcome in experimental models of stroke. Several drug-like small molecules targeting the NLRP3 inflammasome are in different phases of development as novel therapeutics for various inflammatory conditions, including stroke. Understanding how these molecules interfere with NLRP3 inflammasome assembly is paramount for their better optimization and/or development of newer NLRP3 inhibitors. In this review, we summarized the assembly of the NLRP3 inflammasome and discussed the recent advances in understanding the upstream regulators of NLRP3 inflammasome-mediated neuroinflammation following stroke. Additionally, we critically examined the role of the NLRP3 inflammasome-mediated signaling in stroke pathophysiology and the development of therapeutic modalities to target the NLRP3 inflammasome-related signaling for stroke treatment.

Farnesoid X receptor activation protects against renal fibrosis via modulation of β-catenin signaling

OBJECTIVE

Activation of farnesoid X receptor (FXR), a bile acid nuclear receptor, may be implicated in the pathophysiology of diabetic nephropathy. We explored a possible role for FXR activation in preventing renal fibrosis in high fat diet (HFD)-fed mice.

METHODS

We investigated the effects of HFD on mouse kidney and renal tubular epithelial cells both in vivo and in vitro, and observed the changes of FXR and β-catenin pathway. FXR agonist was also used to alleviate this HFD-induced effect, and the interaction between FXR and β-catenin was further verified.

RESULTS

Mice were fed by a 60% kcal fat diet for 20 weeks developed the typical traits of metabolic syndrome with subsequent renal lipid accumulation and renal injury. Treatment with the FXR agonist CDCA or GW4064 decreased body weight, renal lipid accumulation, as well as renal injury. Moreover, renal β-catenin signaling was activated and improved with FXR-agonist treatment in HFD-fed mice. To examine whether FXR affected β-catenin signaling, and was involved in tubulo-interstitial fibrosis, we explored the FXR expression and function in ox-LDL induced-renal tubular injury. In rat proximal tubular epithelial cells (NRK-52E) stimulated by ox-LDL, FXR protein was decreased compared to control group, and phosphorylated (Ser675) β-catenin was activated by ox-LDL in a dose- and time-dependent manner. Ox-LDL enhanced α-SMA and fibronectin expressions and reduced E-cadherin levels, whereas FXR agonism or FXR overexpression inhibited fibronectin and α-SMA expressions and restored E-cadherin. Moreover, FXR agonist treatment also decreased phosphorylated (Ser675) β-catenin, nuclear translocation and β-catenin-mediated transcription induced by ox-LDL in NRK-52E cells. We showed that FXR could bind with β-catenin via the AF1 domain, and disrupt the assembly of the core β-catenin/TCF4 complex.

CONCLUSION

These experimental data suggest that FXR activation, via modulating β-catenin signaling, may contribute to attenuating the development of lipid-mediated tubulo-interstitial fibrosis.

Angiotensin II type-2 receptor attenuates liver fibrosis progression by suppressing IRE1α-XBP1 pathway

The renin-angiotensin system (RAS) has been recognized as a crucial contributor to the development of liver fibrosis, and AT2R, an essential component of RAS, is involved in the progression of liver fibrosis. However, the underlying mechanisms by which AT2R modulates liver fibrosis remain elusive. Here, we report that AT2R was induced to be highly expressed during the progression of liver fibrosis, and the elevated AT2R attenuates liver fibrosis by suppressing IRE1α-XBP1 pathway. In this study, we found that AT2R is not expressed in the no cirrhotic adult liver, but is induced expression during liver fibrosis in both cirrhotic patients and fibrotic mice models. Upregulated AT2R inhibits the activation and proliferation of hepatic stellate cells (HSCs). In addition, our study showed that during liver fibrosis, AT2R deletion increased the dimerization activation of IRE1α and promoted XBP1 splicing, and the spliced XBP1s could promote their transcription by binding to the AT2R promoter and repress the IRE1α-XBP1 axis, forming an AT2R-IRE1α-XBP1 negative feedback loop. Importantly, the combination treatment of an AT2R agonist and an endoplasmic reticulum stress (ER stress) alleviator significantly attenuated liver fibrosis in a mouse model of liver fibrosis. Therefore, we conclude that the AT2R-IRE1α signaling pathway can regulate the progression of liver fibrosis, and AT2R is a new potential therapeutic target for treating liver fibrosis.

NLRP3 inflammatory pathway. Can we unlock depression?

Depression holds the title of the largest contributor to worldwide disability, with the numbers expected to continue growing. Currently, there are neither reliable biomarkers for the diagnosis of the disease nor are the current medications sufficient for a lasting response in nearly half of patients. In this comprehensive review, we analyze the previously established pathophysiological models of the disease and how the interplay between NLRP3 inflammasome activation and depression might offer a unifying perspective. Adopting this inflammatory theory, we explain how NLRP3 inflammasome activation emerges as a pivotal contributor to depressive inflammation, substantiated by compelling evidence from both human studies and animal models. This inflammation is found in the central nervous system (CNS) neurons, astrocytes, and microglial cells. Remarkably, dysregulation of the NLRP3 inflammasome extends beyond the CNS boundaries and permeates into the enteric and peripheral immune systems, thereby altering the microbiota-gut-brain axis. The integrity of the brain blood barrier (BBB) and intestinal epithelial barrier (IEB) is also compromised by this inflammation. By emphasizing the central role of NLRP3 inflammasome activation in depression and its far-reaching implications, we go over each area with potential modulating mechanisms within the inflammasome pathway in hopes of finding new targets for more effective management of this debilitating condition.

Bacteroides fragilis alleviates necrotizing enterocolitis through restoring bile acid metabolism balance using bile salt hydrolase and inhibiting FXR-NLRP3 signaling pathway

Necrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality in premature infants with no specific treatments available. We aimed to identify the molecular mechanisms underlying NEC and investigate the therapeutic effects of Bacteroides fragilis on NEC. Clinical samples of infant feces, bile acid-targeted metabolomics, pathological staining, bioinformatics analysis, NEC rat model, and co-immunoprecipitation were used to explore the pathogenesis of NEC. Taxonomic characterization of the bile salt hydrolase (bsh) gene, enzyme activity assays, 16S rRNA sequencing, and organoids were used to explore the therapeutic effects of B. fragilis on NEC-related intestinal damage. Clinical samples, NEC rat models, and in vitro experiments revealed that total bile acid increased in the blood but decreased in feces. Moreover, the levels of FXR and other bile acid metabolism-related genes were abnormal, resulting in disordered bile acid metabolism in NEC. Taurochenodeoxycholic acid accelerated NEC pathogenesis and taurodeoxycholate alleviated NEC. B. fragilis displayed bsh genes and enzyme activity and alleviated intestinal damage by restoring gut microbiota dysbiosis and bile acid metabolism abnormalities by inhibiting the FXR-NLRP3 signaling pathway. Our results provide valuable insights into the therapeutic role of B. fragilis in NEC. Administering B. fragilis may substantially alleviate intestinal damage in NEC.

Endoplasmic reticulum stress-mediated autophagy alleviates lipopolysaccharide-induced nucleus pulposus cell pyroptosis by inhibiting CHOP signaling in vitro

Pyroptosis, a newly discovered pro-inflammatory programmed necrosis of cells, serves as an initiating and promoting event that leads to intervertebral disc (IVD) degeneration (IDD). Endoplasmic reticulum stress (ERS) and autophagy are vital regulatory mechanisms of cellular homeostasis, which is also closely related to IDD. However, the role and relationship of ERS and autophagy in the pyroptosis of nucleus pulposus cell (NPC) are not well understood. In this research, we aimed to elucidate the role and mechanism of ERS-C/EBP homologous protein (CHOP) in lipopolysaccharide (LPS)-induced cell pyroptosis and determine its interaction with autophagy. ERS and autophagy inducers or inhibitors were used or not in the preconditioning of rat NPCs. Cell viability, pyroptosis-related protein expression, caspase-1 activity assay, and enzyme-linked immunosorbent assay were performed to observe rat NPC pyroptosis after the treatment of LPS. Activation of the ERS pathway and autophagy were assessed by quantitative real-time PCR, western blot analyses, and immunofluorescence staining assay to classify the molecular mechanisms. Our results showed that LPS stimulation induced NPC pyroptosis with concomitant activation of the ERS-CHOP pathway and initiated autophagy. Activation of the ERS-CHOP pathway exacerbated rat NPC pyroptosis, whereas autophagy inhibited cell pyroptosis. LPS-induced cell pyroptosis and CHOP upregulation were negatively regulated by autophagy. LPS-induced autophagy was depressed by the ERS inhibitor but aggravated by the ERS inducer. Taken together, our findings suggested that LPS induced NPC pyroptosis by activating ERS-CHOP signaling and ERS mediated LPS-induced autophagy, which in turn alleviated NPC pyroptosis by inhibiting CHOP signaling.

CREBH promotes autophagy to ameliorate NASH by regulating Coro1a

Dysfunctional autophagy aggravates oxidative stress and inflammation in hepatocytes and accelerates the progression of nonalcoholic steatohepatitis (NASH). Here, we demonstrated that cAMP-responsive element-binding protein H (CREBH) is a transcriptional regulator of hepatic autophagy in response to diet-induced NASH. The results showed that the upregulation of CREBH in lipid-overloaded hepatocytes improves cell damage, dysfunction of autophagic flux and associated abnormal accumulation of the autophagosome marker LC3-II and autophagic substrate p62. CREBH deficiency aggravated the dysfunctional autophagy and liver injury and even caused NASH-associated liver fibrosis. In addition, the changing trend of autolysosomes and lysosome membrane-associated protein (LAMP1) was consistent with the expression level of CREBH. This result indicated that CREBH might promote autophagic degradation by restoring the formation of autolysosomes, thereby improving the blocked autophagic flux. Moreover, we observed that CREBH inhibited the expression of Coronin 1a (Coro1a), an autophagosome-lysosome fusion-related gene, through transcriptional regulation. The overexpression of Coro1a in LO2 liver cells inhibited autophagic flux and elevated inflammatory cytokine levels upon palmitic acid (PA) stimulation. Overall, our findings provide new insights into the regulatory role of CREBH in the progression of NASH and reveal that Coro1a is a novel target gene of CREBH based on the autophagy pathway.

Restraint stress promotes nonalcoholic steatohepatitis by regulating the farnesoid X receptor/NLRP3 signaling pathway

Psychological stress promotes nonalcoholic steatohepatitis (NASH) development. However, the pathogenesis of psychological stress-induced NASH remains unclear. This study aims to explore the underlying mechanism of restraint stress-induced NASH, which mimics psychological stress, and to discover potential NASH candidates. Methionine choline deficient diet- and high fat diet-induced hepatosteatotic mice are subjected to restraint stress to induce NASH. The mice are administrated with Xiaoyaosan granules, NOD-like receptor family pyrin domain containing 3 (NLRP3) inhibitors, farnesoid X receptor (FXR) agonists, or macrophage scavengers. Pathological changes and NLRP3 signaling in the liver are determined. These results demonstrate that restraint stress promotes hepatic inflammation and fibrosis in hepatosteatotic mice. Restraint stress increases the expressions of NLRP3, Caspase-1, Gasdermin D, interleukin-1β, cholesterol 7α-hydroxylase, and sterol 12α-hydroxylase and decreases the expression of FXR in NASH mice. Xiaoyaosan granules reverse hepatic inflammation and fibrosis and target FXR and NLRP3 signals. In addition, inhibition of NLRP3 reduces the NLRP3 inflammasome and liver damage in mice with restraint stress-induced NASH. Elimination of macrophages and activation of FXR also attenuate inflammation and fibrosis by inhibiting NLRP3 signaling. However, NLRP3 inhibitors or macrophage scavengers fail to affect the expression of FXR. In conclusion, restraint stress promotes NASH-related inflammation and fibrosis by regulating the FXR/NLRP3 signaling pathway. Xiaoyaosan granules, NLRP3 inhibitors, FXR agonists, and macrophage scavengers are potential candidates for the treatment of psychological stress-related NASH.

HFD-exacerbated Metabolic Side Effects of Olanzapine Are Suppressed by ER Stress Inhibitor

OBJECTIVE

Numerous schizophrenic patients are suffering from obesity primarily attributed to antipsychotic medication and poor dietary habits. This study investigated the progressive deterioration of olanzapine-induced metabolic disorders in the presence of a high-fat diet (HFD) and explored the involvement of endoplasmic reticulum (ER) stress.

METHODS

Female Sprague-Dawley rats fed on a standard chow diet or HFD were treated with olanzapine (3 mg/kg/day) and the ER stress inhibitor 4-phenylbutyric acid (4-PBA, 1 and 0.5 g/kg/day) for 8 days. Changes in body weight, food intake, and plasma lipids were assessed. Hepatic fat accumulation was evaluated using oil red O staining. Western blotting and immunofluorescence assays were employed to examine the expression of ER stress markers, NOD-like receptor pyrin domain-containing protein 3 (NLRP3), and proopiomelanocortin (POMC) in the hypothalamus or liver.

RESULTS

Compared to olanzapine alone, olanzapine+HFD induced greater weight gain, increased hyperlipidemia, and enhanced hepatic fat accumulation (P<0.05). Co-treatment with 4-PBA exhibited a dose-dependent inhibition of these effects (P<0.05). Further mechanistic investigations revealed that olanzapine alone activated ER stress, upregulated NLRP3 expression in the hypothalamus and liver, and downregulated hypothalamic POMC expression. The HFD exacerbated these effects by 50%-100%. Moreover, co-administration of 4-PBA dose-dependently attenuated the olanzapine+HFD-induced alterations in ER stress, NLRP3, and POMC expression in the hypothalamus and liver (P<0.05).

CONCLUSION

HFD worsened olanzapine-induced weight gain and lipid metabolic disorders, possibly through ER stress-POMC and ER stress-NLRP3 signaling. ER stress inhibitors could be effective in preventing olanzapine+HFD-induced metabolic disorders.

Insights into the underlying pathogenesis and therapeutic potential of endoplasmic reticulum stress in degenerative musculoskeletal diseases

Degenerative musculoskeletal diseases are structural and functional failures of the musculoskeletal system, including osteoarthritis, osteoporosis, intervertebral disc degeneration (IVDD), and sarcopenia. As the global population ages, degenerative musculoskeletal diseases are becoming more prevalent. However, the pathogenesis of degenerative musculoskeletal diseases is not fully understood. Previous studies have revealed that endoplasmic reticulum (ER) stress is a stress response that occurs when impairment of the protein folding capacity of the ER leads to the accumulation of misfolded or unfolded proteins in the ER, contributing to degenerative musculoskeletal diseases. By affecting cartilage degeneration, synovitis, meniscal lesion, subchondral bone remodeling of osteoarthritis, bone remodeling and angiogenesis of osteoporosis, nucleus pulposus degeneration, annulus fibrosus rupture, cartilaginous endplate degeneration of IVDD, and sarcopenia, ER stress is involved in the pathogenesis of degenerative musculoskeletal diseases. Preclinical studies have found that regulation of ER stress can delay the progression of multiple degenerative musculoskeletal diseases. These pilot studies provide foundations for further evaluation of the feasibility, efficacy, and safety of ER stress modulators in the treatment of musculoskeletal degenerative diseases in clinical trials. In this review, we have integrated up-to-date research findings of ER stress into the pathogenesis of degenerative musculoskeletal diseases. In a future perspective, we have also discussed possible directions of ER stress in the investigation of degenerative musculoskeletal disease, potential therapeutic strategies for degenerative musculoskeletal diseases using ER stress modulators, as well as underlying challenges and obstacles in bench-to-beside research.

Farnesoid X receptor in chronic liver diseases: an immunohistochemical study

Chronic hepatitis C virus (HCV) related liver diseases are still an ongoing cause of hepatic failure despite the effective role of direct-acting anti-viral agents. Farnesoid X receptor (FXR) agonists have a potential therapeutic effect on the management of chronic liver diseases (CLD). However, data regarding FXR protein expression in human CLDs are limited and conflicting. We aimed to assess the immunohistochemical expression of FXR in HCV-related chronic hepatitis and cirrhosis in comparison with metabolic-associated fatty liver disease (MAFLD) and normal liver tissue. The expression of FXR was low both in hepatocytes and bile ducts of HCV-related chronic hepatitis and cirrhosis (p = .001, respectively). In addition, a significantly low expression of FXR was observed in HCV-related hepatitis and cirrhosis groups compared to MAFLD in hepatocytes (p < .001, for both) and bile ducts (p = .004 and p = .018). FXR expression in HCV-related cirrhosis was significantly associated with compensated liver function (p = .032) and low inflammatory activity (p = .022). FXR expression decreases in HCV-related CLDs. There was some evidence that FXR expression could protect against post-hepatitis cirrhosis.

Resveratrol improves emamectin benzoate-induced pyroptosis and inflammation of Ctenopharyngodon idellus hepatic cells by alleviating oxidative stress/endoplasmic reticulum stress

Emamectin benzoate (EMB) is the most widely used pesticide in the world and contributes to water pollution. Owing to the lack of a specific antidote, EMB has a severe negative impact on the health of aquatic organisms. Resveratrol (RES), a substance with antioxidant capacity, is secreted by the fruits of many plants. This study was to explore the protection of RES against EMB-induced pyroptosis and inflammatory response in grass carp (Ctenopharyngodon idellus) hepatic liver (L8824) cells by oxidative stress/endoplasmic reticulum (ER) stress. The results showed that compared to the CON group, EMB induced oxidative stress in L8824 cells with the increase of reactive oxygen species (ROS), methane dicarboxylic aldehyde (MDA), and hydrogen peroxide (H2O2) contents and the decrease of total superoxide dismutase (t-sod) and glutathione peroxidase (gsh-px) activities (P < 0.05). In addition, EMB triggered ERS, increasing the relative mRNA expression of protein kinase R-like endoplasmic reticulum kinase (perk), inositol requiring enzyme 1 alpha (ire1α), glucose-regulated protein 78 (grp78), activating transcription factor 4 (atf4), activating transcription factor 6 (atf6), and CCAAT-enhancer-binding protein homologous protein (chop) and the protein expression of eukaryotic initiation factor 2α (eif2α), chop, atf6, and atf4. Meanwhile, EMB further induced pyroptosis by upregulating the mRNA and protein expression of nlrp3, aptamer protein (asc), caspase-1, gsdmd, interleukin-1β (il-1β), and interleukin-18 (il-18). EMB also induced inflammation in L8824 cells by increasing the mRNA expression of interleukin-2 (il-2), interleukin-6 (il-6), tumor necrosis factor-α (tnf-α), and ifn-γ and decreasing the content of interleukin-10 (il-10). However, compared to the EMB group, the oxidant indices and expression of genes related to ER stress, pyroptosis, and pro-inflammatory factors were significantly down-regulated (P < 0.05), whereas the antioxidant indicators and anti-inflammatory factor were significantly up-regulated in the EMB + RES group (P < 0.05). In conclusion, EMB caused hepatocytes pyroptosis and inflammation in grass carp, and RES could alleviate EMB-induced pyroptosis and inflammation in L8824 cells by ameliorating oxidative stress/ER stress.

Effects of toxicants on endoplasmic reticulum stress and hepatic cell fate determination

Toxicant-induced injury is a significant global health issue. However, the mechanisms through which toxicants such as carbon tetrachloride, acetaminophen, dimethylformamide, cocaine, and morphine induce the death of multiple cell types and contribute to liver toxicity are highly complex. This phenomenon involves intricate signaling pathways in association with oxidative stress, inflammation, and activation of death receptors, which are closely linked to endoplasmic reticulum (ER) stress. ER stress initially triggers the unfolded protein response, which either promotes cell survival or causes cell death at later times, depending on the severity and duration of the stress. Thus, comprehending the molecular basis governing cell fate determination in the context of ER stress may provide key insights into the prevention and treatment of toxicant-induced injury. This review summarizes our current understanding of agents that trigger different forms of ER stress-mediated cell death, necroptosis, ferroptosis, pyroptosis, and apoptosis, and covers the underlying molecular basis of toxicant-induced ER stress, as well as potential target molecules.