Inhibition of heme-thiolate monooxygenase CYP1B1 prevents hepatic stellate cell activation and liver fibrosis by accumulating trehalose.

Activation of extracellular matrix-producing hepatic stellate cells (HSCs) is a key event in liver fibrogenesis. We showed that the expression of the heme-thiolate monooxygenase cytochrome P450 1B1 (CYP1B1) was elevated in human and mouse fibrotic livers and activated HSCs. Systemic or HSC-specific ablation and pharmacological inhibition of CYP1B1 attenuated HSC activation and protected male but not female mice from thioacetamide (TAA)-, carbon tetrachloride (CCl4)-, or bile duct ligation (BDL)-induced liver fibrosis. Metabolomic analysis revealed an increase in the disaccharide trehalose in CYP1B1-deficient HSCs resulting from intestinal suppression of the trehalose-metabolizing enzyme trehalase, whose gene we found to be a target of RARα. Trehalose or its hydrolysis-resistant derivative lactotrehalose exhibited potent antifibrotic activity in vitro and in vivo by functioning as an HSC-specific autophagy inhibitor, which may account for the antifibrotic effect of CYP1B1 inhibition. Our study thus reveals an endobiotic function of CYP1B1 in liver fibrosis in males, mediated by liver-intestine cross-talk and trehalose. At the translational level, pharmacological inhibition of CYP1B1 or the use of trehalose/lactotrehalose may represent therapeutic strategies for liver fibrosis.

CircRNA_001373 promotes liver fibrosis by regulating autophagy activation in hepatic stellate cells via the miR-142a-5p/Becn1 axis.

The purpose of this study was to investigate the regulatory role and underlying mechanisms of circRNA_001373 in the hepatic stellate cell (HSC) activation. Quantitative real-time polymerase chain reaction was used to detect the expression of circRNA_001373, miR-142a-5p and Becn1. The viability of JS-1 cells was measured by Cell Counting Kit-8. The targeting relationship between miR-142a-5p and CircRNA_001373, as well as between miR-142a-5p and Becn1 was predicted using CircInteractome and TargetScan databases, respectively, and validated by dual-luciferase reporter assay. Western blot was utilized to determine the expression levels of proteins related to autophagy and the activation if HSCs in JS-1 cells. After activation by platelet-derived growth factor-BB, an increase was observed in the expression of collagen I and α-smooth muscle actin proteins. The expression of CircRNA_001373 was up-regulated in the activated HSCs. Knockdown of CircRNA_001373 significantly inhibited cell viability and activation of JS-1 cells, as well as autophagy in the activated HSCs. CircRNA_001373 could sponge miR-142a-5p in the activated HSCs, which in turn elevated the Becn1 expression. Concurrent knockdown of both CircRNA_001373 and miR-142a-5p reversed the inhibitory effects of the knockdown of CircRNA_001373 alone on cell viability and autophagy in activated JS-1 cells. CircRNA_ 001373 promotes cell viability and autophagy as well as the activation of JS-1 cells by regulating the miR-142a-5p/Becn1 axis.

[Analysis of core functional components in Yinchenhao Decoction and their pathways for treating liver fibrosis].

OBJECTIVE: To analyze the core functional component groups (CFCG) in Yinchenhao Decoction (YCHD) and their possible pathways for treating hepatic fibrosis based on network pharmacology. METHODS: PPI data were extracted from DisGeNET, Genecards, CMGRN and PTHGRN to construct a weighted network using Cytoscape 3.9.1. The data of the chemical components in YCHD were obtained from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP), and the potential active components and targets were selected using PreADMET Web server and SwissTargetPrediction. A fusion model was constructed to obtain the functional effect space and evaluate the effective proteins to identify the CFCG followed by GO and KEGG pathway enrichment analyses for all the targets. In cultured human hepatic stellate cells (LX-2 cells), the cytotoxicity of different compounds in YCHD was tested using CCK-8 assay; the effects of these compounds on collagen α1 (Col1a1) mRNA expression and the pathways in 20 ng/mL TGF-ß1-stimulated cells were analyzed using RT-qPCR and Western blotting. RESULTS: A total of 1005 pathogenic genes, 226 potential active components and 1529 potential targets in YCHD and 52 potential targets of CFCG were obtained. Benzyl acetate, vanillic acid, clorius, polydatin, lauric acid and ferulic acid were selected for CCK-8 verification, and they all showed minimal cytotoxicity below the concentration of 200 µmol/L. Clorius, polydatin, lauric acid and ferulic acid all effectively inhibited TGF-ß1-induced LX-2 cell activation. At the concentration of 200 µmol/L, all these 4 components inhibited PI3K, p-PI3K, AKT, p-AKT, ERK, p-ERK, P38 MAPK and p-P38 MAPK expressions in TGF-ß1-induced LX-2 cells. CONCLUSION: The therapeutic effect of YCHD on hepatic fibrosis is probably mediated by its core functional components including benzyl acetate, vanillic acid, clorius, polydatin, lauric acid and ferulic acid, which inhibit the PI3K-AKT and MAPK pathways in hepatic stellate cells.

Exogenous S1P via S1P receptor 2 induces CTGF expression through Src-RhoA-ROCK-YAP pathway in hepatic stellate cells.

BACKGROUND: Hepatic fibrosis, a prevalent chronic liver condition, involves excessive extracellular matrix production associated with aberrant wound healing. Hepatic stellate cells (HSCs) play a pivotal role in liver fibrosis, activated by inflammatory factors such as sphingosine 1-phosphate (S1P). Despite S1P's involvement in fibrosis, its specific role and downstream pathway in HSCs remain controversial. METHODS: In this study, we investigated the regulatory role of S1P/S1P receptor (S1PR) in Hippo-YAP activation in both LX-2 cell lines and primary HSCs. Real-time PCR, western blot, pharmacological inhibitors, siRNAs, and Rho activity assays were adopted to address the molecular mechanisms of S1P mediated YAP activation. RESULTS: Serum and exogenous S1P significantly increased the expression of YAP target genes in HSCs. Pharmacologic inhibitors and siRNA-mediated knockdowns of S1P receptors showed S1P receptor 2 (S1PR2) as the primary mediator for S1P-induced CTGF expression in HSCs. Results using siRNA-mediated knockdown, Verteporfin, and Phospho-Tag immunoblots showed that S1P-S1PR2 signaling effectively suppressed the Hippo kinases cascade, thereby activating YAP. Furthermore, S1P increased RhoA activities in cells and ROCK inhibitors effectively blocked CTGF induction. Cytoskeletal-perturbing reagents were shown to greatly modulate CTGF induction, suggesting the important role of actin cytoskeleton in S1P-induced YAP activation. Exogeneous S1P treatment was enough to increase the expression of COL1A1 and α-SMA, that were blocked by YAP specific inhibitor. CONCLUSIONS: Our data demonstrate that S1P/S1PR2-Src-RhoA-ROCK axis leads to Hippo-YAP activation, resulting in the up-regulation of CTGF, COL1A1 and α-SMA expression in HSCs. Therefore, S1PR2 may represent a potential therapeutic target for hepatic fibrosis.

Carthamus tinctorius L. inhibits hepatic fibrosis and hepatic stellate cell activation by targeting the PI3K/Akt/mTOR pathway.

Hepatic fibrosis (HF) is a process that occurs during the progression of several chronic liver diseases, for which there is a lack of effective treatment options. Carthamus tinctorius L. (CTL) is often used in Chinese or Mongolian medicine to treat liver diseases. However, its mechanism of action remains unclear. In the present study, CTL was used to treat rats with CCl4­induced HF. The histopathological, biochemical and HF markers of the livers of the rats were analyzed, and CTL­infused serum was used to treat hepatic stellate cells (HSCs) in order to detect the relevant markers of HSC activation. Protein expression pathways were detected both in vitro and in vivo. Histopathological results showed that CTL significantly improved CCl4­induced liver injury, reduced aspartate aminotransferase and alanine aminotransferase levels, promoted E­cadherin expression, and decreased α­smooth muscle actin (SMA), SOX9, collagen I and hydroxyproline expression. Moreover, CTL­infused serum was found to decrease α­SMA and collagen I expression in HSCs. Further studies showed that CTL inhibited the activity of the PI3K/Akt/mTOR pathway in the rat livers. Following the administration of the PI3K agonist 740Y­P to HSCs, the inhibitory effect of CTL on the PI3K/Akt//mTOR pathway was blocked. These results suggested that CTL can inhibit HF and HSC activation by inhibiting the PI3K/Akt/mTOR pathway.

Vitamin D receptor attenuates carbon tetrachloride-induced liver fibrosis via downregulation of YAP.

Liver fibrosis is characterized by the excessive accumulation of extracellular matrix proteins, which can lead to cirrhosis and liver cancer. Metabolic dysfunction-associated steatosis liver diseases are common causes of liver fibrosis, sharing a similar pathogenesis with carbon tetrachloride (CCl4) exposure. This process involves the activation of hepatic stellate cells (HSCs) into myofibroblasts. However, the detailed mechanism and effective treatment strategies require further investigation. In this study, we uncovered a negative correlation between VDR expression and YAP within HSCs. Subsequently, we demonstrated that VDR exerted a downregulatory influence on YAP transcriptional activity in HSCs. Intriguingly, activation VDR effectively inhibited the culture induced activation of primary HSCs by suppressing the transcriptional activity of early YAP. Furthermore, in vivo results manifested that hepatic-specific deletion of YAP/TAZ ameliorates CCl4-induced liver fibrosis, and nullified the antifibrotic efficacy of VDR. Importantly, a YAP inhibitor rescued the exacerbation of liver fibrosis induced by hepatic-specific VDR knockout. Moreover, the combined pharmacological of VDR agonist and YAP inhibitor demonstrated a synergistic effect in diminishing CCl4-induced liver fibrosis, primary HSCs activation and hepatic injury in vivo. These effects were underpinned by their collective ability to inhibit HSC activation through AMPK activation, consequently curbing ATP synthesis and HSCs proliferation. In conclusion, our results not only revealed the inhibition of VDR on YAP-activated liver stellate cells but also identified a synergistic effect of VDR agonist and YAP inhibitor in an AMPKα-dependent manner, providing a practical foundation for integration of multi-targeted drugs in the therapy of CCl4-induced hepatic fibrosis.

Sequential system based on ferritin delivery system and cell therapy for modulating the pathological microenvironment and promoting recovery.

The vicious crosstalk among capillarization of hepatic sinusoidal endothelial cells (LSECs), activation of hepatic stellate cells (aHSCs), and hepatocyte damage poses a significant impediment to the successful treatment of liver fibrosis. In this study, we propose a sequential combination therapy aimed at disrupting the malignant crosstalk and reshaping the benign microenvironment while repairing damaged hepatocytes to achieve effective treatment of liver fibrosis. Firstly, H-subunit apoferrin (Ferritin) was adopted to load platycodonin D (PLD) and MnO2, forming ferritin@MnO2/PLD (FMP) nanoparticles, which exploited the high affinity of ferritin for the highly expressed transferrin receptor 1 (TfR1) to achieve the precise targeted delivery of FMP in the liver. Upon PLD intervention, restoration of the fenestration pores in capillarized LSECs was facilitated by modulating the phosphatidyl inositol 3-kinase/protein kinase B (PI3K/AKT) and Kruppel Like Factor 2 (KLF2) signaling pathways both in vitro and in vivo, enabling efficient entry of FMP into the Disse space. Subsequently, FMP NPs effectively inhibited HSC activation by modulating the TLR2/TLR4/NF-κB-p65 signaling pathway. Moreover, FMP NPs efficiently scavenged reactive oxygen species (ROS) and mitigated the expression of inflammatory mediators, thereby reshaping the microenvironment to support hepatocyte repair. Finally, administration of bone marrow mesenchymal stem cells (BMMSCs) was employed to promote the regeneration and functional recovery of damaged hepatocytes. In conclusion, the combined sequential therapy involving FMP and BMMSCs effectively attenuated liver fibrosis induced by CCl4 administration, resulting in significant amelioration of the fibrotic condition. The therapeutic strategy outlined in this study underscores the significance of disrupting the deleterious cellular interactions and remodeling the microenvironment, thereby presenting a promising avenue for clinical intervention in liver fibrosis.

A novel experimental mouse model of diabetic nonalcoholic steatohepatitis: A critical role for acid-sensitive Ion Channel 1a.

BACKGROUND: A two-way relationship exists between type 2 diabetes (T2DM) and human nonalcoholic steatohepatitis (NASH). Several diabetic NASH models have the disadvantages of long cycles or inconsistent with the actual incidence of human disease, which would be costly and time-consuming to investigate disease pathogenesis and develop drugs. Therefore, there is an urgent need to establish a diabetic NASH mouse model. METHODS: The combination between Fructose-palmitate-cholesterol diet (FPC) and Streptozotocin (STZ) (FPC+STZ) was used to construct diabetic NASH mouse model. The in vivo effects of silencing acid-sensitive Ion Channel 1a (ASIC1a) were examined with an adeno-associated virus 9 (AAV9) carrying ASIC1a short hairpin RNA (shRNA) in FPC+STZ model. RESULTS: The mice fed with FPC for 12 weeks had insulin resistance, hyperinsulinemia, lipid accumulation, and increased hepatic levels of inflammatory factors. However, it still did not develop remarkable liver fibrosis. Most interestingly, noticeable fibrotic scars were observed in the liver of mice from FPC+STZ group. Furthermore, insulin therapy significantly ameliorated FPC+STZ-induced NASH-related liver fibrosis, indicating that hyperglycemia is of great significance in NASH development and progression. Importantly, ASIC1a was found to be involved in the pathogenesis of diabetic NASH as demonstrated that silencing ASIC1a in HSCs significantly ameliorated FPC+STZ-induced NASH fibrosis. Mechanistically, ASIC1a interacted with Poly Adp-adenosine ribose polymerase (PARP1) to promote HSC activation by inducing autophagy. CONCLUSION: A FPC diet combined with an injection of STZ induces a diabetic NASH mouse model in a shorter period. Targeting ASIC1a may provide a novel therapeutic target for the treatment of diabetic NASH.

Pregnane X receptor inhibits the transdifferentiation of hepatic stellate cells by down-regulating periostin expression.

Pregnane X receptor (PXR) is a xenobiotic-sensing nuclear receptor that plays a key role in drug metabolism. Recently, PXR was found to attenuate the development of liver cancer by suppressing epithelial-mesenchymal transition (EMT) in liver cancer cells in a mouse model of two-stage chemical carcinogenesis. To elucidate the role of PXR in the EMT of liver cancer cells, we focused on its role in hepatic stellate cells (HSCs), which are components of the tumor microenvironment in hepatocellular carcinoma (HCC). Human HSC-derived LX-2 cells stably expressed destabilization domain (DD)-fused human PXR (hPXR-LX2 cells). Human HCC-derived HepG2 cells were transfected with the EMT marker VIM promoter-regulated reporter plasmid and co-cultured with hPXR-LX2 cells or treated with hPXR-LX2-derived conditioned medium (CM). Co-culture or CM treatment increased reporter activity in HepG2 cells. This induction was attenuated upon PXR activation in hPXR-LX2 cells by treatment with the DD-stabilizing chemical Shield-1 and the human PXR ligand rifampicin. PXR activation in hPXR-LX2 cells exhibited inhibition of TGF-ß1-induced transdifferentiation, supported by observations of morphological changes and protein or mRNA levels of the transdifferentiation markers COL1A1 and FN1. PXR activation in hPXR-LX2 cells also attenuated the mRNA levels of the key transdifferentiation factor, POSTN. Treatment of hPXR-LX2 cells with recombinant POSTN restored the PXR-mediated suppression of transdifferentiation. Reporter assays with the POSTN promoter showed that PXR inhibited the NF-κB-mediated transcription of POSTN. Consequently, PXR activation in HSCs is expected to inhibit transdifferentiation by down-regulating POSTN expression, thereby suppressing EMT of liver cancer cells.

GSK805 inhibits alpha-smooth muscle expression and modulates liver inflammation without impairing the well-being of mice.

Cholestatic liver diseases, such as primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC), lead to inflammation and severe hepatic damage with limited therapeutic options. This study assessed the efficacy of the inverse RORγt agonist, GSK805, both in vitro using the hepatic stellate cell-line LX-2 and in vivo using male bile duct-ligated BALB/c mice. In vitro, 0.3 µM GSK805 reduced alpha-smooth muscle actin expression in LX-2 cells. In vivo, GSK805 significantly decreased IL-23R, TNF-α, and IFN-γ expression in cholestatic liver. Despite high concentrations of GSK805 in the liver, no significant reduction in fibrosis was noticed. GSK805 significantly increased aspartate aminotransferase and alanine aminotransferase activity in the blood, while levels of glutamate dehydrogenase, alkaline phosphatase, and bilirubin were not substantially increased. Importantly, GSK805 did neither increase an animal distress score nor substantially reduce body weight, burrowing activity, or nesting behavior. These results suggest that a high liver concentration of GSK805 is achieved by daily oral administration and that this drug modulates inflammation in cholestatic mice without impairing animal well-being.

Experimental study on H2O2 activation of HSC-T6 and hepatic fibrosis in cholestatic mice by "Yajieshaba".

ETHNOPHARMACOLOGICAL RELEVANCE: Yajieshaba (YJSB), approved by the Yunnan Provincial Food and Drug Administration in 2008, are known for their anti-inflammatory, antiviral, and pro-apoptotic properties, effectively treating Hepatic fibrosis (HF). However, its mechanism of action remains unclear. AIM OF THE STUDY: The objective of this investigation is to explore how YJSB influences the TGF-ß1/Smad signaling pathway as a strategy for reducing HF. METHODS: The establishment of a HF model in mice involved ligation of the common bile duct, followed by administration of YJSB. Body and liver weights were measured, and the liver index calculated. Serum levels of ALT, AST, ALP, TBA, and TBIL were assessed using colorimetric methods. Additionally, liver homogenates were analyzed for PIIINP, Col-IV, LN, HA, and Hyp, as well as TGF-ß1 activity, using ELISA. Histological analyses of liver sections, stained with H&E, Ag, and Masson's trichrome, were performed to examine inflammation and the accumulation of collagen and reticular fibers. These studies aimed to elucidate the pharmacodynamic effects of YJSB on HF in mice with bile duct obstruction. The target pathways of YJSB were preliminarily identified through immunofluorescence detection of TGF-ß1, P-Smad2L, P-Smad2C, P-Smad3L, P-Smad3C, and Smad4 proteins. In vitro experiments included the induction of hepatic stellate cell (HSC-T6) activation by H2O2. A cell injury model was established for HSC-T6, and the CCK-8 assay was used to determine the optimal YJSB concentration and treatment duration. After pirfenidone (PFD) administration, which inhibits the TGF-ß1/Smad pathway, the effects of YJSB on HSC-T6 cell proliferation were observed. ELISA assays quantified Col-III, α-SMA, and Col-I in cell lysates to assess YJSB's impact on collagen synthesis in HSC-T6 cells. Western blot analysis was performed to assess the protein levels within the TGF-ß1/Smad signaling cascade. RESULTS: In the HF mouse model, administration of YJSB notably augmented the body weight and reduced the liver index. Concurrently, there was an elevation in serum concentrations of ALP, AST, ALT, TBA, and TBIL. Similarly, in the liver homogenates of HF mice, increases were observed in the levels of HA, PIIINP, Col-IV, LN, Hyp, and TGF-ß1. Histological assessments using H&E, Ag, and Masson stains indicated a substantial diminution in liver tissue damage. Through immunofluorescence analysis, it was discerned that YJSB modulated the expression of TGF-ß1, P-Smad2L, P-Smad2C, and P-Smad3L downwards, while elevating P-Smad3C and Smad4 protein expressions. Additional investigations revealed a significant reduction in α-SMA, Col-I, and Col-III levels in cell culture fluids, suggesting a decrease in collagen synthesis and a protective role against cellular damage. Western blot analyses demonstrated that the TGF-ß1/Smad pathway inhibitor, PFD, acted in synergy with YJSB, enhancing its regulatory effects on this pathway, decreasing levels of TGF-ß1, P-Smad2L, P-Smad2C, P-Smad3L, and promoting the expression of P-Smad3C. CONCLUSIONS: YJSB demonstrates a pharmacodynamic effect against HF, enhancing liver functionality and effectively mitigating the damage associated with bile duct obstruction. The proposed action mechanism of YJSB involves modulation of the TGF-ß1/Smad signaling pathway. Research indicates that YJSB might play a role in suppressing the movement, programmed cell death, and activation of HSC-T6, potentially decelerating the advancement of hepatic fibrosis.

Cell-specific AHR-driven differential gene expression in the mouse liver cell following acute TCDD exposure.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a persistent environmental contaminant that disrupts hepatic function leading to steatotic liver disease (SLD)-like pathologies, such as steatosis, steatohepatitis, and fibrosis. These effects are mediated by the aryl hydrocarbon receptor following changes in gene expression. Although diverse cell types are involved, initial cell-specific changes in gene expression have not been reported. In this study, differential gene expression in hepatic cell types was examined in male C57BL/6 mice gavaged with 30 µg/kg of TCDD using single-nuclei RNA-sequencing. Ten liver cell types were identified with the proportions of most cell types remaining unchanged, except for neutrophils which increased at 72 h. Gene expression suggests TCDD induced genes related to oxidative stress in hepatocytes as early as 2 h. Lipid homeostasis was disrupted in hepatocytes, macrophages, B cells, and T cells, characterized by the induction of genes associated with lipid transport, steroid hormone biosynthesis, and the suppression of ß-oxidation, while linoleic acid metabolism was altered in hepatic stellate cells (HSCs), B cells, portal fibroblasts, and plasmacytoid dendritic cells. Pro-fibrogenic processes were also enriched, including the induction retinol metabolism genes in HSCs and the early induction of anti-fibrolysis genes in hepatocytes, endothelial cells, HSCs, and macrophages. Hepatocytes also had gene expression changes consistent with hepatocellular carcinoma. Collectively, these findings underscore the effects of TCDD in initiating SLD-like phenotypes and identified cell-specific gene expression changes related to oxidative stress, steatosis, fibrosis, cell proliferation and the development of HCC.

In Vitro Investigation of the Anti-Fibrotic Effects of 1-Phenyl-2-Pentanol, Identified from Moringa oleifera Lam., on Hepatic Stellate Cells.

Liver fibrosis, characterized by excessive extracellular matrix deposition, is driven by activated hepatic stellate cells (HSCs). Due to the limited availability of anti-fibrotic drugs, the research on therapeutic agents continues. Here we have investigated Moringa oleifera Lam. (MO), known for its various bioactive properties, for anti-fibrotic effects. This study has focused on 1-phenyl-2-pentanol (1-PHE), a compound derived from MO leaves, and its effects on LX-2 human hepatic stellate cell activation. TGF-ß1-stimulated LX-2 cells were treated with MO extract or 1-PHE, and the changes in liver fibrosis markers were assessed at both gene and protein levels. Proteomic analysis and molecular docking were employed to identify potential protein targets and signaling pathways affected by 1-PHE. Treatment with 1-PHE downregulated fibrosis markers, including collagen type I alpha 1 chain (COL1A1), collagen type IV alpha 1 chain (COL4A1), mothers against decapentaplegic homologs 2 and 3 (SMAD2/3), and matrix metalloproteinase-2 (MMP2), and reduced the secretion of matrix metalloproteinase-9 (MMP-9). Proteomic analysis data showed that 1-PHE modulates the Wnt/ß-catenin pathway, providing a possible mechanism for its effects. Our results suggest that 1-PHE inhibits the TGF-ß1 and Wnt/ß-catenin signaling pathways and HSC activation, indicating its potential as an anti-liver-fibrosis agent.

DGAT1 and DGAT2 Inhibitors for Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) Management: Benefits for Their Single or Combined Application.

Inhibiting diacylglycerol acetyltransferase (DGAT1, DGAT2) enzymes (iDGAT1, iDGAT2), involved in triglyceride (TG) synthesis, improves hepatic steatosis in metabolic dysfunction-associated steatotic liver disease (MASLD) patients. However, their potential synergism in disease onset (SLD) and progression (metabolic dysfunction-associated steatohepatitis, fibrosis) has been poorly explored. We investigated iDGAT1 and iDGAT2 efficacy, alone or combined (iDGAT1/2) on fat accumulation and hepatocellular injury in hepatocytes (HepG2) and on fibrogenic processes in hepatic stellate cells (LX2). We further tested whether the addition of MitoQ antioxidant to iDGAT1/2 would enhance their effects. SLD and MASH conditions were reproduced in vitro by supplementing Dulbecco's Modified Eagle's Medium (DMEM) with palmitic/oleic acids (PAOA) alone (SLD-medium), or plus Lipopolisaccaride (LPS), fructose, and glucose (MASH-medium). In SLD-medium, iDGAT1 and iDGAT2 individually, and even more in combination, reduced TG synthesis in HepG2 cells. Markers of hepatocellular damage were slightly decreased after single iDGAT exposure. Conversely, iDGAT1/2 counteracted ER/oxidative stress and inflammation and enhanced mitochondrial Tricarboxylic acid cycle (TCA) and respiration. In HepG2 cells under a MASH-like condition, only iDGAT1/2 effectively ameliorated TG content and oxidative and inflammatory mediators, further improving bioenergetic balance. LX2 cells, challenged with SLD/MASH media, showed less proliferation and slower migration rates in response to iDGAT1/2 drugs. MitoQ combined with iDGAT1/2 improved cell viability and dampened free fatty acid release by stimulating ß-oxidation. Dual DGAT inhibition combined with antioxidants open new perspectives for MASLD management.

Specnuezhenide ameliorates hepatic fibrosis via regulating SIRT6-Mediated inflammatory signaling cascades.

ETHNOPHARMACOLOGICAL RELEVANCE: Ligustrum lucidum W.T. Aiton is a traditional Chinese medicine that has long been used with high hepatoprotective therapeutic and condition value. Specnuezhenide (SP), the standard prominent secoiridoid compound of Fructus Ligustri Lucidi may ameliorate hepatic inflammation in chronic liver diseases. AIM OF THE STUDY: Regulating inflammation through SIRT6-P2X7R axis has caused the emergence of novel molecular mechanism strategies for reversing hepatic fibrosis. This study focused on the mechanism of SP in modulating the liver inflammatory microenvironment in hepatic fibrosis. MATERIALS AND METHODS: C57BL/6 mice with hepatic fibrosis were stimulated with thioacetamide (TAA) prior to administration of SP. Hepatic stellate cells (HSCs) or normal mouse primary hepatocytes were exposed to transforming growth factor-ß (TGF-ß) treatment. Meanwhile, normal mouse bone marrow-derived macrophages (BMDMs) were treated with lipopolysaccharide/adenosine triphosphate (LPS/ATP), aiming to obtain the conditioned medium. HSCs and hepatocytes were transfected with SIRT6 knockdown vector (siRNA-SIRT6) to estimate the impact of SP on the SIRT6-P2X7R/NLRP3 signaling pathway. RESULTS: SP suppressed the HSCs extracellular matrix (ECM) deposition as well as pro-inflammatory cytokine levels induced by the medium of BMDMs or TGF-ß. In addition, SP also significantly up-regulated SIRT6, inhibited P2X7R-NLRP3 inflammasome in HSCs and hepatocytes, and functioned as MDL-800 (a SIRT6 agonist). SP reduced the hepatocytes pyroptosis and further prevented the occurrence of inflammatory response in the liver. SP could inhibit the activation of BMDMs and impede IL-1ß and IL-18 from entering extracellular regions. Moreover, deficiency of SIRT6 in HSCs or hepatocytes reduced SP's regulation of P2X7R suppression. For TAA-treated mice, SP mitigated histopathological changes, ECM accumulation, EMT process, and NETs formation in hepatic fibrosis. CONCLUSIONS: Therefore, SP decreased inflammatory response via SIRT6-P2X7R/NLRP3 pathway and suppressed fibrillogenesis. These findings supported SP as the novel candidate to treat hepatic fibrosis.

Gentiana decoction inhibits liver fibrosis and the activation of hepatic stellate cells via upregulating the expression of Parkin.

Liver fibrosis is a wound-healing process. It can be induced by various chronic liver diseases. Liver fibrosis is characterized by the activation of hepatic stellate cells (HSCs), a key event. However, no effective treatment strategies to cure or alleviate liver fibrosis-induced pathologic changes have yet been developed. Traditional Chinese medicine (TCM) exhibits a good anti-fibrosis action, with few side effects. Gentiana decoction, a TCM also called Longdan Xiegan Tang (LXT), is used for purging the liver in clinical settings. However, the role of LXT in preventing liver fibrosis and the underlying regulatory mechanism have not yet been investigated. This study demonstrates that LXT treatment can protect the liver from the injuries resulting from CCl4-induced liver fibrosis in mice and suppress the activation of HSCs. The mice in the LXT group exhibit litter collagen I and HSC activation marker α-smooth muscle actin (α-SMA) expression. Transcriptome sequencing of the mouse liver tissue reveals that the level of Parkin, a mitophagy marker, decreased in CCl4-induced liver fibrosis. Further study shows that the injection of Parkin-overexpression adeno-associated virus (Parkin-AAV) via the tail vein can reduce CCl4-induced liver fibrogenesis in mice. We conducted a mechanistic study also, which suggests that LXT treatment suppresses the activation of HSCs by upregulating the expression of Parkin. Hence, it can be suggested that LXT inhibits liver fibrosis by activating the Parkin signaling pathway.

Microplastic-induced hepatic adverse effects evaluated in advanced quadruple cell human primary models following three weeks of repeated exposure.

Nano and microplastics are defined as particles smaller than 100 nm and 5 mm respectively. The widespread production and use of plastics in everyday life has resulted in significant accumulation of plastic debris in the environment. Over the last two decades there are increased concerns regarding the potential entry and accumulation of plastics in the human body with ingestion being one of the most important routes of exposure. However, the magnitude and nature of potential toxic effects of plastic exposure to human health is not yet fully understood. The liver is the body's principal detoxification organ and critically to this study recognized as the main accumulation site for particulates. In this study as the first of its kind the health impacts of long term low repeated polystyrene microplastics (1 and 5 µm) exposure was investigated in a functionally active 3D liver microtissue model, composed of primary human hepatocytes, Kupffer cells, sinusoidal endothelial cells and hepatic stellate cells. The highlight from the data includes microplastic-induced dose (3.125-25 µg/ml) and time dependent (up to 504 h) increase in cell death and inflammation manifested by enhanced release of IL6, IL8 and TNF-α. The exposure to repeated dosing of the plastics also resulted in notable pathology manifested as aberrant tissue architecture, such as dilated bile canaliculi and large lipid droplets inside the hepatic cells. This toxicity matched extremely well to the accumulation of the materials with the cells of microtissue predominately in the organ macrophages. This study highlights the real issue and danger of microplastic exposure with potential for long-term accumulation and adverse effects of non-biodegradable plastics within the liver.

Trimethylamine N-oxide induces non-alcoholic fatty liver disease by activating the PERK.

Nonalcoholic fatty liver disease (NAFLD) is a liver disease causing different progressive pathological changes. Trimethylamine N-oxide (TMAO), a product of gut microbiota metabolism, is a specific agonist of the protein kinase R-like endoplasmic reticulum kinase (PERK) pathway, one of the endoplasmic reticulum stress (ERS) pathways. TMAO has been associated with the occurrence and development of NAFLD based on the results of previous studies, but whether the simple consumption of TMAO can directly induce NAFLD and its underlying mechanism remain unclear. To investigate this question, we constructed an animal model in which adult male zebrafish were fed a controlled diet containing 1 % or 3 % TMAO for 20 weeks. Eventually, we observed that TMAO caused lipid accumulation, inflammatory infiltration, liver injury and liver fibrosis in zebrafish livers; meanwhile, the PERK signaling pathway was activated in the zebrafish livers. This finding was further confirmed in HepG2 cells and hepatic stellate cells models. In conclusion, this study found that TMAO directly induced different pathological states of NAFLD in zebrafish liver, and the activation of PERK pathway is an important mechanism, which may provide crucial strategies for the diagnosis and treatment of NAFLD.

PPARß/δ attenuates hepatic fibrosis by reducing SMAD3 phosphorylation and p300 levels via AMPK in hepatic stellate cells.

The role of peroxisome proliferator-activated receptor (PPAR)ß/δ in hepatic fibrosis remains a subject of debate. Here, we examined the effects of a PPARß/δ agonist on the pathogenesis of liver fibrosis and the activation of hepatic stellate cells (HSCs), the main effector cells in liver fibrosis, in response to the pro-fibrotic stimulus transforming growth factor-ß (TGF-ß). The PPARß/δ agonist GW501516 completely prevented glucose intolerance and peripheral insulin resistance, blocked the accumulation of collagen in the liver, and attenuated the expression of inflammatory and fibrogenic genes in mice fed a choline-deficient high-fat diet (CD-HFD). The antifibrogenic effect of GW501516 observed in the livers CD-HFD-fed mice could occur through an action on HSCs since primary HSCs isolated from Ppard-/- mice showed increased mRNA levels of the profibrotic gene Col1a1. Moreover, PPARß/δ activation abrogated TGF-ß1-mediated cell migration (an indicator of cell activation) in LX-2 cells (immortalized activated human HSCs). Likewise, GW501516 attenuated the phosphorylation of the main downstream intracellular protein target of TGF-ß1, suppressor of mothers against decapentaplegic (SMAD)3, as well as the levels of the SMAD3 co-activator p300 via the activation of AMP-activated protein kinase (AMPK) and the subsequent inhibition of extracellular signal-regulated kinase-1/2 (ERK1/2) in LX-2 cells. Overall, these findings uncover a new mechanism by which the activation of AMPK by a PPARß/δ agonist reduces TGF-ß1-mediated activation of HSCs and fibrosis via the reduction of both SMAD3 phosphorylation and p300 levels.

Key regulators of hepatic stellate cell activation in alcohol liver Disease: A comprehensive review.

Alcoholic liver disease (ALD) is a broad category of disorders that begin with liver injury, lead to liver fibrosis, and ultimately conclude in alcohol-induced liver cirrhosis, the most chronic and irreversible liver damage. Liver fibrosis (LF) is a common pathological characteristic observed in most chronic liver inflammatory conditions that involve prolonged inflammation. In this review, we have summarized ethanol-mediated hepatic stellate cell (HSCs) activation and its role in liver fibrosis progression. We highlight important molecular mechanisms that are modulated by ethanol, play a role in the activation of HSCs and the progression of liver fibrosis and identifying potential targets to ameliorate liver fibrosis.