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.

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.

The effects of simvastatin-loaded nanoliposomes on human multilineage liver fibrosis microtissue.

In this in vitro study, for the first time, we evaluate the effects of simvastatin-loaded liposome nanoparticles (SIM-LipoNPs) treatment on fibrosis-induced liver microtissues, as simvastatin (SIM) has shown potential benefits in the non-alcoholic fatty liver disease process. We developed multicellular liver microtissues composed of hepatic stellate cells, hepatoblastoma cells and human umbilical vein endothelial cells. The microtissues were supplemented with a combination of palmitic acid and oleic acid to develop fibrosis models. Subsequently, various groups of microtissues were exposed to SIM and SIM-LipoNPs at doses of 5 and 10 mg/mL. The effectiveness of the treatments was evaluated by analysing cell viability, production of reactive oxygen species (ROS) and nitric oxide (NO), the expression of Kruppel-like factor (KLF) 2, and pro-inflammatory cytokines (interleukin(IL)-1 α, IL-1 ß, IL-6 and tumour necrosis factor-α), and the expression of collagen I. Our results indicated that SIM-LipoNPs application showed promising results. SIM-LipoNPs effectively amplified the SIM-klf2-NO pathway at a lower dosage compatible with a high dosage of free SIM, which also led to reduced oxidative stress by decreasing ROS levels. SIM-LipoNPs administration also resulted in a significant reduction in pro-inflammatory cytokines and Collagen I mRNA levels, as a marker of fibrosis. In conclusion, our study highlights the considerable therapeutic potential of using SIM-LipoNPs to prevent liver fibrosis progress, underscoring the remarkable properties of SIM-LipoNPs in activating the KLF2-NO pathway and anti-oxidative and anti-inflammatory response.

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.

Apigenin intervenes in liver fibrosis by regulating PKM2-HIF-1α mediated oxidative stress.

Apigenin (API) is a natural flavonoid compound with antioxidant, anti fibrotic, anti-inflammatory and other effects, but there is limited research on the effect of API on liver fibrosis. This study aims to explore the effect and potential mechanism of API on liver fibrosis induced by CCl4 in mice. The results indicate that API reduces oxidative stress levels, inhibits hepatic stellate cell (HSC) activation, and exerts anti liver fibrosis effects by regulating the PKM2-HIF-1α pathway. We observed that API alleviated liver tissue pathological damage and collagen deposition in CCl4 induced mouse liver fibrosis model, promoting the recovery of liver function in mice with liver fibrosis. In addition, the API inhibits the transition of Pyruvate kinase isozyme type M2 (PKM2) from dimer to tetramer formation by regulating the EGFR-MEK1/2-ERK1/2 pathway, thereby preventing dimer from entering the nucleus and blocking PKM2-HIF-1α access. This change leads to a decrease in malondialdehyde (MDA) and Catalase (CAT) levels and an increase in glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX) levels, as well as total antioxidant capacity (T-AOC) in the liver of liver fibrosis mice. At the same time, API downregulated the expression of α-smooth muscle actin (α-SMA), Vimentin and Desmin in the liver tissue of mice with liver fibrosis, inhibited the activation of HSC, and reduced collagen deposition. These results indicate that API can inhibit HSC activation and alleviate CCl4 induced liver fibrosis by inhibiting the PKM2-HIF-1α pathway and reducing oxidative stress, laying an important foundation for the development and clinical application of API as a novel drug for treating liver fibrosis.

Naringenin ameliorates MASH fibrosis via regulating TAK1/MAPK/FoxO3a-mediated apoptosis in the activated hepatic stellate cells.

This study aims to explore the regulating effect and mechanism of naringenin (NGN) on the hepatic stellate cells (HSCs) apoptosis and its preventive effects on MASH fibrosis. C57BL/6 mice were subjected to either high-fat diet (HFD) plus carbon tetrachloride (CCl4) injection (HFD + CCl4) for 8 weeks to induce a MASH fibrosis model or bile duct ligation (BDL) to establish a liver fibrosis model, NGN was administered by gavage. LX2 cells were stimulated by oleic acid (OA) and lipopolysaccharide (LPS) (OA + LPS) to study the effects of NGN on activated hepatic stellate cell (HSC). Additionally, LO2 cells stimulated with OA + LPS were used to assess the protective effects of NGN on lipotoxicity of hepatocytes. Our in vivo results showed that NGN administration effectively inhibited mouse liver fibrosis in both of the MASH model and BDL model. The in vitro results indicate that NGN directly inhibited HSCs activation and promoted apoptosis of the activated HSCs, while it suppressed the apoptosis of LO2 cells induced by OA + LPS. The underlying mechanisms were mainly elucidated through the reduction of TAK1 phosphorylation, leading to the downregulation of p-JNK and p-ERK expression. This in turn, inhibited the phosphorylation of FoxO3a and promoted the nuclear localization of FoxO3a. Consequently, this may enhance the transcription of apoptosis-related genes, resulting in the apoptosis of activated HSCs. In conclusion, NGN ameliorates MASH fibrosis by enhancing apoptosis of the activated HSCs. The inhibitory effects of NGN on the TAK1/MAPK/FoxO3a pathway were demonstrated as its preventive mechanisms against MASH fibrosis.

Lycorine relieves the CCl4-induced liver fibrosis mainly via the JAK2/STAT3 and PI3K/AKT signaling pathways.

Liver fibrosis, a progressive process of fibrous scarring, results from the accumulation of extracellular matrix proteins (ECM). If left untreated, it often progresses to diseases such as cirrhosis and hepatocellular carcinoma. Lycorine, a natural alkaloid derived from medicinal plants, has shown diverse bioactivities by targeting JAK2/STAT3 signaling, but its pharmacological effects and potential molecular mechanisms in liver fibrosis remains largely unexplored. The purpose of this study is to elucidate the pharmacological activity and molecular mechanism of lycorine in anti-hepatic fibrosis. Findings indicate that lycorine significantly inhibited hepatic stellate cells (HSCs) activation by reducing the expression of α-SMA and collagen-1. In vivo, lycorine treatment alleviated carbon tetrachloride (CCl4) -induced mice liver fibrosis, improving liver function, decreasing ECM deposition, and inhibiting fibrosis-related markers' expression. Mechanistically, it was found that lycorine exerts protective activity through the JAK2/STAT3 and PI3K/AKT signaling pathways, as evidenced by transcriptome sequencing technology and small molecule inhibitors. These results underscore lycorine's potential as a therapeutic drug for liver fibrosis.

Targeted inhibition of autophagy in hepatic stellate cells by hydroxychloroquine: An effective therapeutic approach for the treatment of liver fibrosis.

BACKGROUND AND PURPOSE: Liver fibrosis is a wound-healing reaction which is the main cause of chronic liver diseases worldwide. The activated hepatic stellate cell (aHSC) is the main driving factor in the development of liver fibrosis. Inhibiting autophagy of aHSC can prevent the progression of liver fibrosis, but inhibiting autophagy of other liver cells has opposite effects. Hence, targeted inhibition of autophagy in aHSC is quite necessary for the treatment of liver fibrosis, which prompts us to explore the targeted delivery system of small molecule autophagy inhibitor hydroxychloroquine (HCQ) that can target aHSC and alleviate the liver fibrosis. METHODS: The delivery system of HCQ@retinol-liposome nanoparticles (HCQ@ROL-LNPs) targeting aHSC was constructed by the film dispersion and pH-gradient method. TGF-ß-induced HSC activation and thioacetamide (TAA)-induced liver fibrosis mice model were established, and the targeting ability and therapeutic effect of HCQ@ROL-LNPs in liver fibrosis were studied subsequently in vitro and in vivo. RESULTS: HCQ@ROL-LNPs have good homogeneity and stability. They inhibited the autophagy of aHSC selectively by HCQ and reduced the deposition of extracellular matrix (ECM) and the damage to other liver cells. Compared with the free HCQ and HCQ@LNPs, HCQ@ROL-LNPs had good targeting ability, showing enhanced therapeutic effect and low toxicity to other organs. CONCLUSION: Construction of HCQ@ROL-LNPs delivery system lays a theoretical and experimental foundation for the treatment of liver fibrosis and promotes the development of clinical therapeutic drugs for liver diseases.

Cholinized-Polymer Functionalized Lipid-Based Drug Carriers Facilitate Liver Fibrosis Therapy via Ultrafast Liver-Targeting Delivery.

Here, we report novel cholinized-polymer functionalized lipid-based nanoparticles (CP-LNPs) for rapid and highly effective delivery of drugs to the liver, achieving targeting within 10 min and nearly 100% efficiency. In this study, CP-LNPs loaded with a promising antifibrotic agent curcumin (CP-LNPs/Cur) significantly improved the stability of curcumin under physiological conditions and its distribution in the liver. In vitro experiments demonstrated that CP-LNPs/Cur effectively suppressed the proliferation and migration of activated hepatic stellate cells (aHSCs), as evidenced by the decreased expression of α-SMA. Moreover, CP-LNPs/Cur attenuated oxidative stress levels in hepatocytes while improving mitochondrial physiological activity. In vivo antifibrosis studies have shown that CP-LNPs/Cur only require a low dose to significantly alleviate liver injury and collagen deposition, thereby preventing the progression of liver fibrosis. These findings indicated that CP-LNPs exhibit great potential in liver fibrosis therapy benefiting from the novel targeting strategy.

Novel Oridonin Analog CYD0682 Inhibits Hepatic Stellate Cell Activation via the Heat Shock Protein 90-Dependent STAT3 Pathway.

INTRODUCTION: Activated hepatic stellate cells (HSCs) are the primary effector cells in hepatic fibrosis, over depositing extracellular matrix (ECM) proteins. Our previous work found oridonin analog CYD0682 attenuates proliferation, Transforming Growth Factor ß (TGFß)-induced signaling, and ECM production in immortalized HSCs. The underlying mechanism behind these reductions is unclear. The Signal Transduction and Activator of Transcription 3 (STAT3) pathway plays a central role in HSC activation and has been found to be overexpressed in models of hepatic injury. In this study, we will examine the effect of CYD0682 on STAT3 signaling. METHODS: Immortalized human (LX-2) and rat (HSC-T6) HSC lines were treated with CYD0682 or Tanespimycin (17-AAG) with or without TGF-ß. Nuclear and cytosolic proteins were extracted. Protein expression was analyzed with Western blot. DNA binding activity was assessed with STAT3 DNA Binding ELISA. Cell viability was assessed with Alamar blue assay. RESULTS: CYD0682 treatment inhibited STAT3 phosphorylation at tyrosine 705 in a dose-dependent manner in LX-2 and HSC-T6 cells. STAT3 DNA binding activity and STAT3 regulated protein c-myc were significantly decreased by CYD0682. Notably, TGFß-induced STAT3 phosphorylation and ECM protein expression were inhibited by CYD0682. STAT3 is reported to be a Heat Shock Protein 90 (HSP90) client protein. Notably, CYD0682 attenuated the expression of endogenous STAT3 and other HSP90 client proteins FAK, IKKα, AKT and CDK9. HSP90 specific inhibitor 17-AAG suppressed endogenous and TGFß-induced STAT3 phosphorylation and ECM protein production. CONCLUSIONS: CYD0682 attenuates endogenous and TGFß-induced STAT3 activation and ECM production via an HSP90 dependent pathway in HSCs. Further study of this pathway may present new targets for therapeutic intervention in hepatic fibrosis.

Exploring novel A2AAR antagonists: Design, synthesis, and evaluation of 2,6,9-trisubstituted purine derivatives as promising antifibrotic agents.

A series of 2,6,9-trisubstituted purine derivatives were designed and synthesized with diverse chemical moieties. Through a comprehensive biological evaluation, we identified 4-(6-(methylamino)-2-(phenylethynyl)-9H-purin-9-yl)phenol (6a) as a promising A2AAR antagonist with potent antifibrotic properties. Compound 6a demonstrated significant efficacy in inhibiting CRE promoter activity and in reducing the expression of fibrogenic marker proteins and downstream effectors of A2AAR activation, surpassing the A2AAR antagonist ZM241385 and initial screening hits, 9-benzyl-N-methyl-2-(phenylethynyl)-9H-purin-6-amine (5a) and 9-((benzyloxy)methyl)-N-methyl-2-(phenylethynyl)-9H-purin-6-amine (5j). Further validation revealed that compound 6a effectively inhibited fibrogenic marker proteins induced by A2AAR overexpression or TGF-ß1 treatment in hepatic stellate cells, alongside reducing PKA and CREB phosphorylation. These findings suggest that compound 6a exerts its antifibrotic action by modulating the cAMP/PKA/CREB pathway through A2AAR inhibition. Overall, our study provides valuable insights for the development of novel therapeutics that target hepatic fibrosis through A2AAR antagonism.

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.

Hydronidone induces apoptosis in activated hepatic stellate cells through endoplasmic reticulum stress-associated mitochondrial apoptotic pathway.

BACKGROUND AND AIM: Hydronidone (HDD) is a novel pirfenidone derivative developed initially to reduce hepatotoxicity. Our previous studies in animals and humans have demonstrated that HDD treatment effectively attenuates liver fibrosis, yet the underlying mechanism remains unclear. This study aimed to investigate whether HDD exerts its anti-fibrotic effect by inducing apoptosis in activated hepatic stellate cells (aHSCs) through the endoplasmic reticulum stress (ERS)-associated mitochondrial apoptotic pathway. METHODS: The carbon tetrachloride (CCl4)- and 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-induced liver fibrosis models were used for in vivo studies. In vitro studies were conducted using the human hepatic stellate cell line LX-2. The apoptotic effect of HDD on aHSCs was examined using TUNEL and flow cytometry assays. The small interfering RNA (siRNA) technique was employed to downregulate the expression of interest genes. RESULTS: HDD treatment significantly promoted apoptosis in aHSCs in both the CCl4- and DDC-induced liver fibrosis in mice and LX-2 cells. Mechanistic studies revealed that HDD triggered ERS and subsequently activated the IRE1α-ASK1-JNK pathway. Furthermore, the influx of cytochrome c from the mitochondria into the cytoplasm was increased, leading to mitochondrial dysfunction and ultimately triggering apoptosis in aHSCs. Notably, inhibition of IRE1α or ASK1 by siRNA partially abrogated the pro-apoptotic effect of HDD in aHSCs. CONCLUSIONS: The findings of both in vivo and in vitro studies suggest that HDD induces apoptosis in aHSCs via the ERS-associated mitochondrial apoptotic pathway, potentially contributing to the amelioration of liver fibrosis.

Mitochondria-targeted reactive oxygen species blockor SS-31 blocks hepatic stellate cell activation and alleviates hepatic fibrosis by regulating NLRP3 inflammasomes.

This study aimed to elucidate the effect of mitochondria-targeted reactive oxygen species (ROS) blockor SS-31 on hepatic stellate cells (HSC) activation during liver fibrosis. TGF-ß1 was employed to induce HSC activation, while MitoSOX Red was utilized to assess the presence of mitochondrial ROS. The mitochondrial membrane potential (MMP) was measured using the JC-1 probe, and the ATP level was determined using a specific kit. The proliferation of HSCs was assessed using CCK-8 and colony formation assays, whereas flow cytometry was employed to detect HSC apoptosis. Fibrotic markers (COL1A1 and α-SMA) and NLRP3 inflammasome components (NLRP3, caspase-1, and ASC) were analyzed via Western blotting. Liver fibrosis was induced in mice using CCl4, and subsequently, histopathological changes were observed through HE staining and Masson staining. In TGF-ß1-activated HSCs, mitochondrial ROS expression increased, MMP and ATP content decreased, indicating mitochondrial damage. After TGF-ß1 induction, HSC proliferation increased, apoptosis decreased, and COL1A1, α-SMA, and NLRP3 inflammasome protein expression increased. After SS-31 treatment, mitochondrial ROS expression decreased, MMP recovered, ATP level increased, HSC proliferation decreased, apoptosis increased, and the expressions of COL1A1, α-SMA, and NLRP3 inflammasome decreased. NLRP3 blockor MCC950 treatment blocked HSC activation. CCL4-induced liver fibrosis mice had inflammatory cell infiltration and significant collagen fiber deposition in the liver. After SS-31 treatment, liver inflammation and collagen deposition were significantly reduced. SS-31, as a mitochondria-targeted ROS blockor, can block HSC activation by regulating the NLRP3 inflammasome, thereby alleviating liver fibrosis.

Heteryunine A, an amidated tryptophan-catechin-spiroketal hybrid with antifibrotic activity from Heterosmilax yunnanensis.

An unprecedented spiro-C-glycoside adduct, heteryunine A (1), along with two uncommon alkaloids featuring a 2,3-diketopiperazine skeleton, heterpyrazines A (2) and B (3), were discovered in the roots of Heterosmilax yunnanensis. The detailed spectroscopic analysis helped to clarify the planar structures of these compounds. Compound 1, containing 7 chiral centers, features a catechin fused with a spiroketal and connects with a tryptophan derivative by a CC bond. Its complex absolute configuration was elucidated by rotating frame overhauser enhancement spectroscopy (ROESY), specific rotation, and the 13C nuclear magnetic resonance (NMR) and electronic circular dichroism (ECD) calculation. The possible biosynthetic routes for 1 were deduced. Compounds 1 and 2 showed significant antifibrotic effects and further research revealed that they inhibited the activation, migration and proliferation of hepatic stellate cells (HSCs) through suppressing the activity of Ras homolog family member A (RhoA).

Group IVA Phospholipase A2 in Collagen-Producing Cells Promotes High-Fat Diet-Induced Infiltration of Inflammatory Cells into the Liver by Upregulating the Expression of MCP-1.

Nonalcoholic steatohepatitis (NASH) is characterized by hepatic inflammation and fibrosis due to excessive fat accumulation. Monocyte chemoattractant protein-1 (MCP-1) is a key chemokine that infiltrates inflammatory cells into the liver during the development of NASH. Our previous studies demonstrated that a systemic deficiency of group IVA phospholipase A2 (IVA-PLA2), an enzyme that contributes to the production of lipid inflammatory mediators, protects mice against high-fat diet-induced hepatic fibrosis and markedly suppresses the CCl4-induced expression of MCP-1 in the liver. However, it remains unclear which cell types harboring IVA-PLA2 are involved in the elevated production of MCP-1. Hence, the present study assessed the types of cells responsible for IVA-PLA2-mediated production of MCP-1 using cultured hepatic stellate cells, endothelial cells, macrophages, and hepatocytes, as well as cell-type specific IVA-PLA2 deficient mice fed a high-fat diet. A relatively specific inhibitor of IVA-PLA2 markedly suppressed the expression of MCP-1 mRNA in cultured hepatic stellate cells, but the suppression of MCP-1 expression was partial in endothelial cells and not observed in monocytes/macrophages or hepatocytes. In contrast, a deficiency of IVA-PLA2 in collagen-producing cells (hepatic stellate cells), but not in other types of cells, reduced the high-fat diet-induced expression of MCP-1 and inflammatory cell infiltration in the liver. Our results suggest that IVA-PLA2 in hepatic stellate cells is critical for hepatic inflammation in the high-fat diet-induced development of NASH. This supports a potential therapeutic approach for NASH using a IVA-PLA2 inhibitor targeting hepatic stellate cells.

Extracellular vesicles originating from steatotic hepatocytes promote hepatic stellate cell senescence via AKT/mTOR signaling.

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is increasing rapidly due to the obesity epidemic. In the inflammatory stages of MASLD (MASH), activation of hepatic stellate cells (HSCs) leads to initiation and progression of liver fibrosis. Extracellular vesicles (EVs) are released from all cell types and play an important role in intercellular communication. However, the role of EVs released from hepatocytes in the context of MASLD is largely unknown. Therefore, the present study aimed to investigate the role of EVs derived from both normal and steatotic (free fatty acid-treated) hepatocytes on the phenotype of HSCs via the senescence pathway. Primary rat hepatocytes were treated with free fatty acids (FFAs: oleic acid and palmitic acid). EVs were collected by ultracentrifugation. EVs markers and HSCs activation and senescence markers were assessed by Western blot analysis, qPCR and cytochemistry. Reactive oxygen species (ROS) production was assessed by fluorescence assay. RNA profiles of EVs were evaluated by sequencing. We found that EVs from hepatocytes treated with FFAs (FFA-EVs) inhibit collagen type 1 and α-smooth muscle actin expression, increase the production of ROS and the expression of senescence markers (IL-6, IL-1ß, p21 and senescence-associated ß-galactosidase activity) in early activating HSCs via the AKT-mTOR pathway. Sequencing showed differentially enriched RNA species between the EVs groups. In conclusion, EVs from FFA-treated hepatocytes inhibit HSC activation by inducing senescence via the AKT-mTOR signaling pathway. Determining the components in EVs from steatotic hepatocytes that induce HSC senescence may lead to the identification of novel targets for intervention in the treatment of MASLD in the future.

Leveraging adrenergic receptor blockade for enhanced nonalcoholic fatty liver disease treatment via a biomimetic nanoplatform.

Nonalcoholic fatty liver disease (NAFLD) is characterized by excessive lipid accumulation, steatosis and fibrosis. Sympathetic nerves play a critical role in maintaining hepatic lipid homeostasis and regulating fibrotic progression through adrenergic receptors expressed by hepatocytes and hepatic stellate cells; however, the use of sympathetic nerve-focused strategies for the treatment of NAFLD is still in the infancy. Herein, a biomimetic nanoplatform with ROS-responsive and ROS-scavenging properties was developed for the codelivery of retinoic acid (RA) and the adrenoceptor antagonist labetalol (LA). The nanoplatform exhibited improved accumulation and sufficient drug release in the fibrotic liver, thereby achieving precise codelivery of drugs. Integration of adrenergic blockade effectively interrupted the vicious cycle of sympathetic nerves with hepatic stellate cells (HSCs) and hepatocytes, which not only combined with RA to restore HSCs to a quiescent state but also helped to reduce hepatic lipid accumulation. We demonstrated the excellent ability of the biomimetic nanoplatform to ameliorate liver inflammation, fibrosis and steatosis. Our work highlights the tremendous potential of a sympathetic nerve-focused strategy for the management of NAFLD and provides a promising nanoplatform for the treatment of NAFLD.

Uncovering the mechanism of troglitazone-mediated idiosyncratic drug-induced liver injury with individual-centric models.

Idiosyncratic drug-induced liver injury is a rare and unpredictable event. Deciphering its initiating-mechanism is a hard task as its occurrence is individual dependent. Thus, studies that utilize models that are not individual-centric might drive to a general mechanistic conclusion that is not necessarily true. Here, we use the individual-centric spheroid model to analyze the initiating-mechanism of troglitazone-mediated iDILI risk. Individual-centric spheroid models were generated using a proprietary cell educating technology. These educated spheroids contain hepatocytes, hepatic stellate cells, activated monocyte-derived macrophages, and dendritic cells under physiological conditions. We show that phases 1 and 2 drug-metabolizing enzymes were induced in an individual-dependent manner. However, we did not observe any association of DEMs induction and troglitazone (TGZ)-mediated iDILI risk. We analyzed TGZ-mediated iDILI and found that a 44-year-old male showed iDILI risk that is associated with TGZ-mediated suppression of IL-12 expression by autologous macrophages and dendritic cells. We performed a rescue experiment and showed that treatment of spheroids from this 44-year-old male with TGZ and recombinant IL-12 suppressed iDILI risk. We confirmed the mechanism in another 31-year-old female with iDILI risk. We demonstrate here that individual-centric spheroid are versatile models that allow to predict iDILI risk and to analyze a direct effect of the drug on activated macrophages and dendritic cells to uncover the initiating-mechanism of iDILI occurrence. This model opens perspectives for a personalized strategy to mitigate iDILI risk.

Albiflorin ameliorates thioacetamide-induced hepatic fibrosis: The involvement of NURR1-mediated inflammatory signaling cascades in hepatic stellate cells activation.

Thioacetamide (TAA) within the liver generates hepatotoxic metabolites that can be induce hepatic fibrosis, similar to the clinical pathological features of chronic human liver disease. The potential protective effect of Albiflorin (ALB), a monoterpenoid glycoside found in Paeonia lactiflora Pall, against hepatic fibrosis was investigated. The mouse hepatic fibrosis model was induced with an intraperitoneal injection of TAA. Hepatic stellate cells (HSCs) were subjected to treatment with transforming growth factor-beta (TGF-ß), while lipopolysaccharide/adenosine triphosphate (LPS/ATP) was added to stimulate mouse peritoneal macrophages (MPMs), leading to the acquisition of conditioned medium. For TAA-treated mice, ALB reduced ALT, AST, HYP levels in serum or liver. The administration of ALB reduced histopathological abnormalities, and significantly regulated the expressions of nuclear receptor-related 1 protein (NURR1) and the P2X purinoceptor 7 receptor (P2×7r) in liver. ALB could suppress HSCs epithelial-mesenchymal transition (EMT), extracellular matrix (ECM) deposition, and pro-inflammatory factor level. ALB also remarkably up-regulated NURR1, inhibited P2×7r signaling pathway, and worked as working as C-DIM12, a NURR1 agonist. Moreover, deficiency of NURR1 in activated HSCs and Kupffer cells weakened the regulatory effect of ALB on P2×7r inhibition. NURR1-mediated inhibition of inflammatory contributed to the regulation of ALB ameliorates TAA-induced hepatic fibrosis, especially based on involving in the crosstalk of HSCs-macrophage. Therefore, ALB plays a significant part in the mitigation of TAA-induced hepatotoxicity this highlights the potential of ALB as a protective intervention for hepatic fibrosis.