LXA4 protected mice from renal ischemia/reperfusion injury by promoting IRG1/Nrf2 and IRAK-M-TRAF6 signal pathways.

Excessive inflammatory response and increased oxidative stress play an essential role in the pathophysiology of ischemia/reperfusion (I/R)-induced acute kidney injury (IRI-AKI). Emerging evidence suggests that lipoxin A4 (LXA4), as an endogenous negative regulator in inflammation, can ameliorate several I/R injuries. However, the mechanisms and effects of LXA4 on IRI-AKI remain unknown. In this study, A bilateral renal I/R mouse model was used to evaluate the role of LXA4 in wild-type, IRG1 knockout, and IRAK-M knockout mice. Our results showed that LXA4, as well as 5-LOX and ALXR, were quickly induced, and subsequently decreased by renal I/R. LXA4 pretreatment improved renal I/R-induced renal function impairment and renal damage and inhibited inflammatory responses and oxidative stresses in mice kidneys. Notably, LXA4 inhibited I/R-induced the activation of TLR4 signal pathway including decreased phosphorylation of TAK1, p36, and p65, but did not affect TLR4 and p-IRAK-1. The analysis of transcriptomic sequencing data and immunoblotting suggested that innate immune signal molecules interleukin-1 receptor-associated kinase-M (IRAK-M) and immunoresponsive gene 1 (IRG1) might be the key targets of LXA4. Further, the knockout of IRG1 or IRAK-M abolished the beneficial effects of LXA4 on IRI-AKI. In addition, IRG1 deficiency reversed the up-regulation of IRAK-M by LXA4, while IRAK-M knockout had no impact on the IRG1 expression, indicating that IRAK-M is a downstream molecule of IRG1. Mechanistically, we found that LXA4-promoted IRG1-itaconate not only enhanced Nrf2 activation and increased HO-1 and NQO1, but also upregulated IRAK-M, which interacted with TRAF6 by competing with IRAK-1, resulting in deactivation of TLR4 downstream signal in IRI-AKI. These data suggested that LXA4 protected against IRI-AKI via promoting IRG1/Itaconate-Nrf2 and IRAK-M-TRAF6 signaling pathways, providing the rationale for a novel strategy for preventing and treating IRI-AKI.

Elucidating Cuproptosis-Associated Genes in the Progression from Nash to HCC Using Bulk and Single-Cell RNA Sequencing Analyses and Experimental Validation.

Background and Objectives: Non-alcoholic steatohepatitis (NASH) is a significant risk factor for hepatocellular carcinoma (HCC) development. Timely treatment during the NASH stage is essential to minimize the possibility of disease progression to HCC. Cuproptosis is a newly identified form of cellular death that could impact the progression of various diseases and cancers. Materials and Methods: Transcriptome and single-cell sequencing datasets were utilized to investigate the role of cuproptosis-related genes (CRGs) in NASH progression to HCC. FDX1, LIPT1, and PDHP were identified as CRGs in NASH patients, and FDX1, DBT, GCSH, SLC31A1, and DLAT were identified as CRGs in patients with NASH progressing to HCC. FDX1 was found to play a significant role in both NASH patients and patients with NASH progressing to HCC. This study constructed cuproptosis-related clusters (CRCs) using the Nonnegative Matrix Factorization algorithm, and they were linked to fatty acid metabolism and the PPAR signaling pathway in both NASH CRCs and HCC CRCs. The Weighted Correlation Network Analysis algorithm identified CRP, CRC, TAT, CXCL10, and ACTA1 as highly relevant genes in NASH CRCs and HCC CRCs. The expression of FDX1 was validated in both mouse models and human NASH samples. Results: The investigation highlights FDX1 as a pivotal CRG in both NASH and NASH progression to HCC. The comprehensive characterization of CRGs sheds light on their potential biofunctional importance in the context of NASH and HCC. Our experimental results show that FDX1 expression was significantly increased in NASH patients. Conclusions: The present study identified key CRGs, revealing their potential impact on NASH and HCC. Meanwhile, targeting FDX1 may prevent the progression of NASH to HCC.

Paeonol alleviates CCl4-induced liver fibrosis through suppression of hepatic stellate cells activation via inhibiting the TGF-ß/Smad3 signaling.

Objective: Paeonol is a natural phenolic component isolated from the root bark of peony with multiple pharmacological activities. We investigated the anti-fibrotic effect and underlying mechanism of paeonol. Methods: Twenty-four male C57BL/6J mice were divided into 4 groups (n = 6 in each group), injected with CCl4 to induce liver fibrosis and administrated with paeonol according to the regimen. The serum activity of ALT and AST, and H&E staining were to assess liver injury. Sirius and Masson staining, and hydroxyproline content were to evaluate the degree of liver fibrosis. TNF-α, IL-6, TGF-ß, MDA, GSH-PX, SOD, and CAT were detected to reflect inflammation and oxidative stress. RT-qPCR and Western blot analysis to assess the activation of HSCs and TGF-ß/Smad3 signaling. Results: Paeonol ameliorated liver injury and liver fibrosis, reflected by the decrease of ALT, AST, less lesion in H&E staining, mitigated fibrosis in Sirius and Masson staining, lessened content of hydroxyproline. Paeonol attenuated the level of IL-6 and TNF-α, and elevated the activity of GSH-PX, SOD, and CAT with reducing the level of MDA. The expression of col 1a, α-SMA, vimentin, and desmin were down-regulated and TGF-ß/Smad3 signaling pathway was inhibited. Conclusion: These data demonstrated that paeonol could alleviate CCl4-induced liver fibrosis through suppression of hepatic stellate cells activation via inhibiting the TGF-ß/Smad3 signaling.

Glycyrrhetinic acid attenuates lipopolysaccharide-induced fulminant hepatic failure in d-galactosamine-sensitized mice by up-regulating expression of interleukin-1 receptor-associated kinase-M.

Glycyrrhetinic acid (GA), the main active ingredient of licorice, reportedly has anti-inflammatory and hepatoprotective properties, but its molecular mechanisms remain be elusive. In the present study, Balb/c mice were pretreated with GA (10, 30, or 100mg/kg) 1h before lipopolysaccharide (LPS)/d-galactosamine (D-GalN) administration. In other in vitro experiment, RAW264.7 macrophages were pretreated with GA before LPS exposure. The mortality, hepatic tissue histology, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were analyzed. Toll like receptor 4 (TLR4), interleukin-1 receptor-associated kinases (IRAKs), activation of mitogen-activated protein kinases (MAPKs) and NF-κB, and production of TNF-α were assessed by flow cytometry, western blotting, and enzyme-linked immunosorbent assay (ELISA), respectively. Our results showed that pretreatment with GA protected mice against LPS/D-GalN-induced fulminant hepatic failure (FHF), including a dose-dependent alleviation of mortality and ALT/AST elevation, ameliorating hepatic pathological damage, and decreasing TNF-α release. Moreover, GA inhibited LPS-induced activation of MAPKs and NF-κB in response to LPS, but the expression of TLR4 was not affected in vivo and in vitro. Notably, GA pretreatment in vivo suppressed IRAK-1 activity while inducing IRAK-M expression. Silencing of IRAK-M expression with siRNA blocked these beneficial effects of GA on the activation of MAPKs and NF-κB as well as TNF-α production in LPS-primed macrophages. Taken together, we conclude that GA could prevent LPS/D-GalN-induced FHF. The underlying mechanisms may be related to up-regulation of IRAK-M, which in turn caused deactivation of IRAK-1 and subsequent MAPKs and NF-κB, resulting in inhibiting TNF-α production.

Resolvin D1 attenuates CCl4-induced acute liver injury involving up-regulation of HO-1 in mice.

Acute hepatic failure involves in excessive oxidative stress and inflammatory responses, leading to a high mortality due to lacking effective therapy. Resolvin D1 (RvD1), an endogenous lipid mediator derived from polyunsaturated fatty acids, has been shown anti-inflammatory and anti-oxidative actions, however, whether RvD1 has protective effects on hepatic failure remains elusive. In this study, the roles and molecular mechanisms of RvD1 were explored in carbon tetrachloride (CCl4)-induced acute liver injury. Our results showed that RvD1 protected mice against CCl4-induced hepatic damage, as evaluated by reduced aminotransferase activities and malondialdehyde content, elevated glutathione and superoxide dismutase activities, and alleviated hepatic pathological damage. Moreover, RvD1 significantly attenuated serum tumor necrosis factor-α and interleukin-6 levels as well as hepatic myeloperoxidase activity, whereas enhanced serum IL-10 level in CCl4-administered mice. Further, RvD1 markedly up-regulated the expression and activity of heme oxygenase-1 (HO-1). However, inhibition of HO-1 activity reversed the protective effects of RvD1 on CCl4-induced liver injury. These results suggest that RvD1 could effectively prevent CCl4-induced liver injury by inhibition of oxidative stress and inflammation, and the underlying mechanism may be related to up-regulation of HO-1.

Sesamin ameliorates lipopolysaccharide/d-galactosamine-induced fulminant hepatic failure by suppression of Toll-like receptor 4 signaling in mice.

Sesamin has been described to exert anti-oxidant and anti-inflammatory properties. In present study, we investigated the potential effects and mechanisms of sesamin on lipopolysaccharide (LPS)-induced fulminant hepatic failure (FHF) in d-galactosamine (D-GalN)-sensitized mice. Our results showed that pretreatment with sesamin dose-dependently improved LPS/D-GalN-induced mortality and liver injury as indicated by reduced serum levels of aminotransferases and alleviated pathological damage as well as hepatocyte apoptosis in mice. Additionally, sesamin markedly attenuated LPS/D-GalN-induced adhesion molecules expression, and decreased neutrophils recruitment. Furthermore, sesamin inhibited LPS-induced tumor necrosis factor-alpha (TNF-α) production, p38 mitogen-activated protein kinases (MAPK) and NF-κB activation, and Toll like receptor (TLR) 4 expression in mice and in RAW264.7 macrophage cells. In summary, these results demonstrate that sesamin protects mice from LPS-induced FHF and the molecular mechanisms may down-regulate the expression of TLR4, block MAPK and NF-κB activation, decrease the production of TNF-α.

PPAR-alpha and PPAR-beta expression changes in the hippocampus of rats undergoing global cerebral ischemia/reperfusion due to PPAR-gamma status.

BACKGROUND: Peroxisome proliferator-activated receptors (PPARs, including alpha, beta and gamma subtypes) and their agonists have a protective role in treatment of central nervous system (CNS) diseases. The present study was designed to investigate the expression changes of PPAR-alpha, -beta, -gamma and NF-kappa B in the hippocampus of rats with global cerebral ischemia/reperfusion injury (GCIRI) after treatment with agonists or antagonists of PPAR-gamma. METHODS: A rat GCIRI model was established by occlusion of bilateral common carotid arteries and cervical vena retransfusion. GW9662 (5 µg), a selective PPAR- gamma antagonist, was intraventricularly injected at 0.5 h before GCIR; Rosiglitazone (0.8, 2.4 and 7.2 mg/kg), a selective PPAR- gamma agonist, was injected intraperitoneally at 1 h before GCIRI. The expression changes of PPAR-alpha, -beta and -gamma at mRNA and protein levels were detected by RT-PCR and western blotting. The changes of spatial learning and memory (SLM) functions were assessed by using a Morris water maze; the pathohistological changes of hippocampal neurons were evaluated by hematoxylin-eosin (HE) staining; the contents of IL-1, IL-6, IL-10 and TNF-alpha, and the NF- kappa B expression were measured by enzyme-linked immunosorbent assay (ELISA) and immunohistochemical staining. The superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were also detected. RESULTS: The SLM function and hippocampal neurons were significantly impaired after the occurrence of GCIRI. The MDA, IL-1, IL-6, IL-10, TNF-alpha content and expression of PPARs increased significantly, but the SOD activity and NF-kappa B expression were weakened in the hippocampus. Rosiglitazone treatment significantly protected rats from SLM function impairment and neuron death, and resulted in higher expressions of SOD activity and NF-kappa B, but lower contents of MDA and inflammatory factors. After treatment with rosiglitazone or GW9662, no significant change in PPAR-alpha or -beta expression was detected. CONCLUSIONS: Rosiglitazone, a PPAR-gamma agonist, plays a protective role in hippocampal neuron damage of GCIRI rats by inhibiting the oxidative stress response and inflammation. The activation or antagonism of PPAR-gamma did not affect the expression of PPAR-alpha or -beta, indicating that the three subtypes of PPARs act in independent pathways in the CNS.

Two undescribed coumarins from Hansenia weberbaueriana.

Two previously undescribed coumarins (1 and 2) were isolated from the root of Hansenia weberbaueriana which have been used to cure inflammatory diseases over thousands of years by Chinese. The structures of new findings were confirmed by comprehensive analyses of spectral evidences in HRESIMS, 1D and 2D NMR combined with chemical calculations. Compounds 1 and 2 exhibited potential anti-inflammatory properties by reducing the mRNA expression levels of TNF-α, IL-6 and IL-1ß in lipopolysaccharide (LPS)-induced RAW264.7 macrophages at a concentration of 15 µM.

Piperine attenuates hepatic ischemia/reperfusion injury via suppressing the TLR4 signaling cascade in mice.

Piperine, the major active substance in black pepper, has been shown to have anti-inflammatory and antioxidant effects in several ischemic diseases. However, the role of piperine in hepatic ischemia/reperfusion injury (HIRI) and its underlying mechanisms remain unclear. In this study, the mice were administered piperine (30 mg/kg) intragastric administration before surgery. After 24 h of hepatic ischemia-reperfusion, liver histopathological evaluation, serum transaminase measurements, and TUNEL analysis were performed. The infiltration of inflammatory cells and production of inflammatory mediators in the liver tissue were determined by immunofluorescence and immunohistochemical staining. The protein levels of toll-like receptor 4 (TLR4) and related proteins such as nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), interleukin-1 receptor-associated kinase 1 (IRAK1), p65, and p38 were detected by western blotting. The results showed that plasma aminotransferase (ALT), aspartate aminotransferase (AST), hepatocyte apoptosis, oxidative stress, and inflammatory cell infiltration significantly increased in HIRI mice. Piperine pretreatment notably repaired liver function, improved the histopathology and apoptosis of liver cells, alleviated oxidative stress injury, and reduced inflammatory cell infiltration. Further analysis showed that piperine attenuated tumor necrosis factor-a (TNF-α) and interleukin 6 (IL-6) production and reduced TLR4 activation and phosphorylation of IRAK1, p38, and NF-κB in HIRI. Piperine has a protective effect against HIRI through the TLR4/IRAK1/NF-κB signaling pathway and may be a safer option for future clinical treatment and prevention of ischemia-related diseases.

Derlin-1 promotes diet-induced non-alcoholic fatty liver disease via increasing RIPK3-mediated necroptosis.

BACKGROUND & AIMS: Unrestricted endoplasmic reticulum (ER) stress and the continuous activation of ER associated protein degradation (ERAD) pathway might lead to the aggravation of non-alcoholic steatohepatitis (NASH). Derlin-1 has been considered to be an integral part of the ERAD pathway, which is involved in the regulation of the transport and excretion of protein degradation products within ER. However, the regulatory role and mechanism of Derlin-1 in NASH remains unclear. METHODS: The expression of Derlin-1 was firstly detected in the liver of normal and NASH animal model and patient. Then, western diet (WD)-induced NASH mice were administrated with the lentivirus-mediated Derlin-1 knockdown or overexpression. Finally, RIPK3 knockout mice were used to explore the mechanism. The liver injury, hepatic steatosis, inflammation, and fibrosis as well as ER stress signal pathway were evaluated. RESULTS: The levels of Derlin-1 were significantly elevated in the liver of WD-fed mice and NASH patients when compared to the control group. Furthermore, Derlin-1 knockdown attenuated WD-induced liver injury, lipid accumulation, inflammatory response, and fibrosis. Conversely, overexpression of Derlin-1 presented the completely opposite results. Mechanistically, Derlin-1 enhanced ER stress pathways and led to necroptosis, and RIPK3 knockout dramatically reduced Derlin-1 expression and reversed the progression of NASH aggravated by Derlin-1. CONCLUSIONS: Notably, Derlin-1 is a critical modulator in NASH. It may accelerate the progression of NASH by regulating the activation of the ERAD pathway and further aggravating the ER stress, which might be involved in RIPK3-mediated necroptosis. Therefore, targeting Derlin-1 as a novel intervention point holds the potential to delay or even reverse NASH.

Protectin D1 inhibits TLR4 signaling pathway to alleviate non-alcoholic steatohepatitis via upregulating IRAK-M.

Non-alcoholic steatohepatitis (NASH) is a prevalent metabolic disease, characterized by the hepatic steatosis, inflammation, and fibrosis, which is lack of effective treatment currently. Protectin D1 (PTD1), a lipid mediator from omega-3 fatty acid docosahexaenoic acid (DHA), has displayed wide pharmacological actions including anti-inflammation in a variety of diseases, but the role of PTD1 on NASH remains unclear. In this study, using the methionine and choline deficient (MCD) fed NASH model, we explored the effect and underlying mechanism of PTD1 on NASH in mice. Our results showed PTD1 improved MCD-induced steatosis, hepatocellular injury, inflammation and fibrosis. Furthermore, PTD1 inhibited MCD-induced activation of TLR4 downstream molecules (TAK1, p38 and p65) without affecting the levels of TLR4 and phosphorylated IRAK-1. Notably, the levels of IRAK-M protein and the binding between IRAK-M and TRAF6 in the liver were also increased by PTD1 in NASH mice. Moreover, IRAK-M knockout remarkedly reverted the beneficial effects of PTD1 on the NASH in mice. Thus, these results demonstrated that PTD1 could protect mice from NASH by inhibiting the activation of TLR4 downstream signaling pathway, which might be related to the upregulation of IRAK-M, indicating that PTD1 may provide a new treatment for NASH.

Chrysin and its nanoliposome ameliorated non-alcoholic steatohepatitis via inhibiting TLR4 signalling pathway.

OBJECTIVES: Non-alcoholic steatohepatitis (NASH) is a chronic liver disease histologically characterized by liver steatosis, hepatocellular injury, inflammation and fibrosis, resulting in cirrhosis and hepatocellular carcinoma, but effective measures and obvious pathogenesis for NASH remain elusive. Chrysin (CH) has been reported to have anti-inflammatory effects but shows lower bioavailability. METHODS: In this study, a chrysin nanoliposome (CH-NL) was first prepared and characterized. Then, we used the methionine-choline-deficient (MCD) diet to induce a mouse model of NASH. Finally, the effects of CH and CH-NL on NASH were evaluated in the liver of NASH mice. KEY FINDINGS: The results showed that CH or CH-NL significantly reduced the accumulation of lipids in hepatocytes, alleviated liver injury, decreased the generation of radical oxygen species, and attenuated the accumulation of collagen fibre in the liver of NASH mice. In addition, CH and its nano-liposomes markedly inhibited the production of inflammatory cytokines and inflammatory cell infiltration in the liver of NASH mice. Further studies found that CH-NL and CH-NL downregulated the MCD diet-induced activation of Toll-like receptor 4 (TLR4) signalling pathway in the liver of mice. CONCLUSIONS: CH and its nanoliposome alleviated MCD diet-induced NASH in mice, which might be through inhibiting TLR4 signalling pathway.

Identification and Analysis of Neutrophil Extracellular Trap-Related Genes in Osteoarthritis by Bioinformatics and Experimental Verification.

Background: Osteoarthritis (OA) is a common joint disease with long-term pain and dysfunction that negatively affects the quality of life of patients. Neutrophil extracellular traps (NETs), consisting of DNA, proteins and cytoplasm, are released by neutrophils and play an important role in a variety of diseases. However, the relationship between OA and NETs is unclear. Methods: In our study, we used bioinformatics to explore the relationship between OA and NETs and the potential biological markers. GSE55235, GSE55457, GSE117999 and GSE98918 were downloaded from the Gene Expression Omnibus (GEO) database for subsequent analysis.After differential analysis of OA expression matrices, intersection with NET-related genes (NRGs) was taken to identify Differentially expressed NRGs (DE-NRGs) in OA processes. Evaluation of immune cell infiltration by ssGSEA and CIBERSORT algorithm. The GSVA method was used to analyze the activity changes of Neutrophils pathway, Neutrophil degranulation and Neutrophil granule constituents pathway. Results: Based on RandomForest (RF), Least Absolute Shrinkage and Selection Operator (LASSO), and Support Vector Machine-Recursive Feature Elimination (SVM-RFE) learning algorithms, five core genes (CRISPLD2, IL1B, SLC25A37, MMP9, and TLR7) were identified to construct an OA-related nomogram model for predicting OA progression. ROC curve results for these genes validated the nomogram's reliability. Correlation analysis, functional enrichment, and drug predictions were performed for the core genes. TLR7 emerged as a key focus due to its high importance ranking in RF and SVM-RFE analyses. Gene Set Enrichment Analysis (GSEA) revealed a strong association between TLR7 and the Neutrophil extracellular trap pathway. Expression of core genes was demonstrated in mice OA models and human OA samples. TLR7 expression in ATDC5 cell line was significantly higher than control after TNFα induction, along with increased IL6 and MMP13. Conclusion: TLR7 may be related to NETs and affects OA.

Sesamin Protects against APAP-Induced Acute Liver Injury by Inhibiting Oxidative Stress and Inflammatory Response via Deactivation of HMGB1/TLR4/NFκB Signal in Mice.

Acetaminophen (APAP) overdose would lead to liver toxicity and even acute liver failure in severe cases by triggering an inflammatory response and oxidative stress. Sesamin has been reported to possess anti-inflammatory and antioxidant actions in several animal disease models. In the present study, the effects and mechanisms of sesamin on APAP-induced acute liver injury (ALI) were explored. The results showed that pretreatment with sesamin significantly alleviated APAP-induced ALI, as indicated by decreased serum aminotransferase activities, hepatic pathological damages, and hepatic cellular apoptosis. But sesamin has no significant effects on the expression of cytochrome P450 2E1 (CYP2E1), APAP-cysteine adducts (APAP-CYS) production, and glutathione content in the liver of APAP-administered mice. Moreover, APAP-induced liver oxidative stress and inflammatory response also were remarkedly attenuated by sesamin, including reducing hepatic reactive oxygen species levels, promoting antioxidant generation, and inhibiting the expression of TNF-α and IL-1ß, as well as decreasing inflammatory cell recruitment. Notably, sesamin inhibited serum high-mobility group box 1 (HMGB1) releases and blocked hepatic activation of Toll-like receptor 4 (TLR4)-interleukin 1 receptor-associated kinase 3-nuclear factor kappa B (NF-κB) signaling pathway in APAP-administered mice. These findings indicated that sesamin could mitigate APAP-induced ALI through suppression of oxidative stress and inflammatory response, which might be mediated by the deactivation of HMGB1/TLR4/NF-κB signaling in mice.

Paeoniflorin modulates oxidative stress, inflammation and hepatic stellate cells activation to alleviate CCl4-induced hepatic fibrosis by upregulation of heme oxygenase-1 in mice.

OBJECTIVES: The role of Paeoniflorin on hepatic fibrosis and the specific mechanisms has not yet been elucidated. Therefore, we explored whether Paeoniflorin exerted protective effects on carbon tetrachloride (CCl4)-induced hepatic fibrosis and the underlying mechanisms. METHODS: A model of hepatic fibrosis was induced by intraperitoneally injecting with CCl4 (10% 5 µl/g) twice a week for 7 weeks. To explore the effects of Paeoniflorin, mice were treated with Paeoniflorin (100 mg/kg) by gavage once a day at 1 week after modeling until they were sacrificed. KEY FINDINGS: Paeoniflorin remarkably improved liver function and histopathological changes of hepatic tissues in CCl4-induced liver injury. Besides, the serum MAO enzyme activity and hydroxyproline contents were notably decreased following the intervention of Paeoniflorin. The decreased expression of Vimentin, α-SMA, Col1a and Desmin manifested the inhibition of the hepatic stellate cells (HSCs) activation. Interestingly, Paeoniflorin intervention significantly upregulated the expression of heme oxygenase-1, and attenuated the inflammatory cytokines production as well as the CCl4-induced oxidative stress imbalance. CONCLUSIONS: Paeoniflorin could effectively alleviate CCl4-induced hepatic fibrosis by upregulation of heme oxygenase-1, and it might be a new effective option for the comprehensive treatment of hepatic fibrosis.

Hesperetin attenuated acetaminophen-induced hepatotoxicity by inhibiting hepatocyte necrosis and apoptosis, oxidative stress and inflammatory response via upregulation of heme oxygenase-1 expression.

Acetaminophen (APAP) is a common antipyretic and analgesic drug, but its overdose can induce acute liver failure with lack of effective therapies. Hesperetin, a dihydrogen flavonoid compound, has been revealed to exert multiple pharmacological activities. Here, we explored the protective effects and mechanism of hesperetin on APAP-induced hepatotoxicity. The results showed that pretreatment with hesperetin dose-dependently attenuated APAP-induced acute liver injury in mice, as measured by alleviated serum enzymes activities, hepatic pathological damage and apoptosis. Moreover, hesperetin mitigated APAP-induced oxidative stress and inflammatory response in mice by inhibiting oxidative molecules but increasing antioxidative molecules production, reducing inflammatory cells infiltration and proinflammatory cytokines production, blocking Toll-like receptor (TLR)-4 signal activation. In vitro experiment indicated that hesperetin dose-dependently inhibited APAP-primed cytotoxicity, apoptosis, and reactive oxygen species (ROS) in murine AML12 hepatocytes. Notably, hesperetin up-regulated expression of heme oxygenase-1 (HO-1) mRNA and protein in the liver of mice and AML12 cells exposed to APAP. Furthermore, knockdown of HO-1 by adenovirus-mediated HO-1 siRNA reverted these beneficial effects of hesperetin on APAP-induced hepatocytotoxicity as well as ROS and inflammatory response in vivo and in vitro. These findings demonstrated that hesperetin exerted a protective prophylaxis on APAP-induced acute liver injury by inhibiting hepatocyte necrosis and apoptosis, oxidative stress and inflammatory response via up-regulating HO-1 expression.

Salidroside protects mice against CCl4-induced acute liver injury via down-regulating CYP2E1 expression and inhibiting NLRP3 inflammasome activation.

Salidroside (Sal), a natural phenolic compound isolated from Rhodiola sachalinensis, has been utilized as anti-inflammatory and antioxidant for centuries, however, its effects against liver injury and the underlying mechanisms are unclear. This study was designed to evaluate the protective effects and underlying mechanisms of Sal on carbon tetrachloride (CCl4)-induced acute liver injury (ALI) in mice. C57BL/6 mice were pretreated with Sal before CCl4 injection, the serum and liver tissue were collected to evaluate liver damage and molecular indices. The results showed that Sal pretreatment dose-dependently attenuated CCl4-induced acute liver injury, as indicated by lowering the activities of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT), and inhibiting hepatic pathological damage and apoptosis. In addition, Sal alleviated CCl4-primed oxidative stress and inflammatory response by restoring hepatic glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), and inhibiting cytokines. Finally, Sal also down-regulated the expression of cytochrome P4502E1 (CYP2E1), and Nod-like receptor protein 3 (NLRP3) inflammasome activation in the liver of mice by CCl4. Our study demonstrates that Sal exerts its hepatoprotective effects on ALI through its antioxidant and anti-inflammatory effects, which might be mediated by down-regulating CYP2E1 expression and inhibiting NLRP3 inflammasome activation.

Mangiferin Attenuates LPS/D-GalN-Induced Acute Liver Injury by Promoting HO-1 in Kupffer Cells.

Acute liver injury and its terminal phase, hepatic failure, trigger a series of complications, including hepatic encephalopathy, systematic inflammatory response syndrome, and multiorgan failure, with relatively high morbidity and mortality. Liver transplantation is the ultimate intervention, but the shortage of donor organs has limited clinical success. Mangiferin (MF), a xanthone glucoside, has been reported to have excellent anti-inflammatory efficacy. Here, a lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced acute liver injury mouse model was established to investigate the protective role of MF and the underlying mechanisms of action. Pretreatment with MF improved survival, decreased serum aminotransferase activities, and inhibited hepatic TNF-α production in LPS/D-GalN-challenged mice. Through Kupffer cell (KC) deletion by GdCl3 and KC adoptive transfer, KCs were confirmed to be involved in these beneficial effects of MF. MF reduced LPS-mediated TNF-α production via the suppression of the TLR4/NF-κB signaling pathway in vitro. MF promoted HO-1 expression, but the knockdown of HO-1 prevented TNF-α inhibition, suggesting that the damage-resistance effects of HO-1 occurred via the suppression of TNF-α synthesis. When HO-1-silenced KCs were transferred to the liver with KC deletion, the protective effect of MF against LPS/D-GalN-induced acute liver injury was reduced, illustrating the role of KC-derived HO-1 in the anti-injury effects of MF. Collectively, MF attenuated acute liver injury induced by LPS/D-GalN via the inhibition of TNF-α production by promoting KCs to upregulate HO-1 expression.

Baicalin and its nanoliposomes ameliorates nonalcoholic fatty liver disease via suppression of TLR4 signaling cascade in mice.

As a natural flavonoid compound, baicalin(BA)has been reported to exhibit hepatoprotective and anti-inflammatory properties. However, the characteristic of poor solubility and low bioavailability greatly limits its application. In addition, the effects and underlying mechanisms of BA in nonalcoholic fatty liver disease (NAFLD) remain elusive. In this study, Methionine and choline deficient diet (MCD)-induced NAFLD mice were treated with baicalin or baicalin-loaded nanoliposomes (BA-NL), then hepatic histopathological changes, biochemical parameters and inflammatory molecules were observed. We found that mice in MCD group showed significant increases in plasma transaminase, hepatocyte apoptosis, hepatic lipid accumulation, liver fibrosis, and infiltration of neutrophils and macrophages compared with control group, however, BA and BA-NL markedly attenuated MCD-induced the above changes. Besides, further analysis indicated that BA and BA-NL also inhibited the up-regulation of toll-like receptor 4 (TLR4) signal and the production of inflammatory mediators in MCD mice. Importantly, BA-NL was found to be more effective than baicalin on MCD-induced NAFLD in mice. These data suggested that BA and its nanoliposomes BA-NL could effectively protect mice against MCD-induced NAFLD, which might be mediated through inhibiting TLR4 signaling cascade.

Geniposide protected hepatocytes from acetaminophen hepatotoxicity by down-regulating CYP 2E1 expression and inhibiting TLR 4/NF-κB signaling pathway.

Acetaminophen (APAP) is a widely used over-the-counter drug for antipyretic and analgesic, but an overdose will induce acute liver injury. APAP hepatotoxicity has been the most common cause of acute liver failure in western countries with high morbidity and mortality. Geniposide (GP), an iridoid glycoside extracted from the fruit of Gardenia jasminoides, has been reported to exert a profound anti-inflammatory activity on acute and chronic diseases. However, it is never demonstrated whether GP can protect hepatocytes from APAP hepatotoxicity. In this study, we investigated the protective effect and underlying mechanism of GP against AILI. The results showed that GP pretreatment reduced the levels of ALT and AST in a dose-dependent manner and alleviated hepatocyte necrosis and apoptosis in mice exposed at APAP. Moreover, it suppressed the expression of CYP 2E1 and attenuated the exhaustion of GSH and accumulation of MDA in the liver. Furthermore, GP remarkably inhibited inflammatory cells infiltration and mitigated the release of IL-1ß and TNF-α, and inhibited Toll-like receptor 4 (TLR4) expression and nuclear factor kappa (NF-κB) activation. These data suggested that GP could effectively protect hepatocytes from APAP hepatotoxicity through the down-regulation of CYP 2E1 expression and the inhibition of TLR4/NF-κB signaling pathway.