Fibrotic Liver Research Articles

Nintedanib attenuates NLRP3 inflammasome-driven liver fibrosis by targeting Src signaling.

Liver injury induces an inflammatory response that activates hepatic stellate cells, which is the initial factor of liver fibrosis. Nintedanib, a multi-targeted tyrosine kinase inhibitor targeting the Src signalling pathway, has been approved for the treatment of idiopathic pulmonary fibrosis. However, it is still not known whether nintedanib ameliorates liver fibrosis by inhibiting inflammasome activation. Here, a carbon tetrachloride (CCl4)-induced liver fibrosis model was used to assess the anti-fibrotic efficacy of nintedanib in vivo. Lipopolysaccharide and ATP were used to activate nucleotide oligomerisation domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasomes in LX-2 cells, and the efficacy of nintedanib on NLRP3 inflammasome activation was evaluated. Moreover, we used Src-overexpressing and Src-downregulating lentiviruses to transfect LX-2 cells to explore the targets of nintedanib. Nintedanib attenuated inflammation and extracellular matrix accumulation in CCl4-induced fibrotic livers and reduced the expression of NLRP3, fibrotic makers, and the phosphorylation of Src, epidermal growth factor receptor (EGFR), AKT, ERK1/2 in LX-2 cells. Furthermore, nintedanib thwarted NLRP3 inflammasome activation by suppressing the phosphorylation of Src and its downstream signalling pathway and reducing reactive oxygen species production. Our study indicates that nintedanib effectively suppresses NLRP3 inflammasome activation and has the potential for the treatment of liver fibrosis.

Target-Engineered Liposomes Decorated with Nanozymes Alleviate Liver Fibrosis by Remodeling the Liver Microenvironment.

Liver fibrosis is a pathological repair response that occurs after sustained liver damage, and prompt intervention is necessary to prevent liver fibrosis from developing into a potentially life-threatening condition. In long-term liver injury, damaged hepatocytes produce excessive amounts of reactive oxygen species (ROS), which activate hepatic stellate cells (HSCs). This activation leads to excessive accumulation of extracellular matrix proteins in liver tissue. Additionally, liver macrophages contribute to the inflammatory microenvironment in the hepatic fibrotic process, exacerbating liver fibrosis through ROS production and the secretion of pro-inflammatory factors. To address the dysregulation of the hepatic microenvironment associated with liver fibrosis, we developed cerium oxide nanozymes using hyaluronic acid (HA) as a template and decorated them on the surface of liposomes loaded with oleanolic acid (OA). We named this prepared and obtained target-engineered liposome HCOL. The inherent superoxide dismutase (SOD) and catalase (CAT) activities of HCOL enabled it to effectively scavenge ROS in HSCs and alleviate the hypoxic conditions characteristic of fibrotic livers. Furthermore, HCOL reduced the concentrations of ROS in macrophages, promoting a shift in macrophage polarization from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype. This transition increased the production of the anti-inflammatory cytokine interleukin 10 (IL-10), which contributed to the mitigation of the inflammatory microenvironment. Consequently, this therapeutic approach proves effective in decelerating the advancement of liver fibrosis.

Ligand-Tethered Extracellular Vesicles Mediated RNA Therapy for Liver Fibrosis.

Liver fibrosis poses a significant global health burden, in which hepatic stellate cells (HSCs) play a crucial role. Targeted nanomedicine delivery systems directed at HSCs have shown immense potential in the treatment of liver fibrosis. Herein, a bioinspired material, engineered therapeutic miR-181a-5p (a miRNA known to inhibit fibrotic signaling pathways) and targeted moiety hyaluronic acid (HA) co-functionalized extracellular vesicles (EVs) are developed. HA is incorporated onto the surface of EVs using DSPE-PEG as a linker, allowing preferential binding to CD44 receptors, which are overexpressed on activated HSCs. Our results confirmed enhanced cellular uptake and improved payload delivery, as evidenced by the increased intracellular abundance of miR-181a-5p in activated HSCs and fibrotic livers. HA-equipped EVs loaded with miR-181a-5p (DPH-EVs@miR) significantly reduce HSC activation and extracellular matrix (ECM) deposition by inhibiting the TGF-β/Smad signaling pathway, thus alleviating the progression of liver fibrosis. Additionally, DPH-EVs@miR improves liver function, ameliorates inflammatory infiltration, and mitigates hepatocyte apoptosis, demonstrating superior hepatic protective effects. Collectively, this study reports a prospective nanovesicle therapeutic platform loaded with therapeutic miRNA and targeting motifs for liver fibrosis. The biomarker-guided EV-engineering technology utilized in this study provides a promising tool for nanomedicine and precision medicine.

Transient receptor potential channel 6 knockout ameliorates hepatic fibrosis by inhibiting the activation and proliferation of hepatic stellate cells.

Hepatic fibrosis is a common outcome of chronic liver injury and can eventually lead to cirrhosis, which is a major public health concern. Hepatic stellate cells (HSCs) are the major producers of extracellular matrix (ECM) and regulate the synthesis and decomposition of ECM, but the specific mechanism of them remains unclear. Transient receptor potential channel 6 (TRPC6), a non-selective cation channel, plays an important role in organic fibrosis. However, the role of TRPC6 in liver fibrosis is rarely studied. Here, we investigated the function of TRPC6 in the activation of the human hepatic stellate cell line LX-2 in vitro and bile duct ligation (BDL)-induced hepatic fibrosis in vivo by western blot, Ca2+ imaging, and immunohistochemistry. We first found that TRPC6 was upregulated in fibrotic liver tissues and TRPC6 knockout inhibited BDL-induced hepatic fibrosis. Transforming growth factor-β1 (TGF-β1) treatment increased TRPC6 expression and thapsigargin (Tg)-mediated SOCE in LX-2 cells, which was decreased by the TRPC6 specific inhibitor SAR7334. Blockage of TRPC6 by SAR7334 or TRPC6-shRNA transfection attenuated TGF-β1-induced LX-2 cell activation and proliferation via the PI3K/AKT/p70S6K signaling pathway. These observations suggested that TRPC6 contribute to LX-2 cell activation and hepatic fibrosis, and downregulation of TRPC6 may become a therapeutic strategy for the treatment of hepatic fibrosis in the future.

Effect of GB1107, a novel galectin-3 inhibitor on pro-fibrotic signalling in the liver

Background and PurposeGalectin-3 (Gal-3) is a pro-fibrotic β-galactoside binding lectin highly expressed in fibrotic liver and implicated in hepatic fibrosis. GB1107 is a novel orally active Gal-3 small molecule inhibitor that has high affinity for Gal-3 >1000-fold selectively over other galectins. The aim of this study was to characterise GB1107 and galectin-3 in vitro and in vivo in the context of fibrosis signalling and liver disease. Experimental ApproachLiver fibrosis was induced by administration of CCl4 twice weekly by intraperitoneal injection in mice for 8 weeks. GB1107 was orally administered once daily (10 mg/kg) for the last 4 weeks of CCl4 treatment. Fibrosis was assessed by picrosirius red staining of FFPE sections. Liver enzymes, Gal-3 and downstream biomarkers were assessed in liver and plasma. Paired-end sequencing was performed on the NextSeq 2000 platform. Pathway enrichment analysis was performed to determine enrichment of differentially expressed genes (DEGs) within Reactome pathways and Gene Ontology (GO) terms. Key ResultsGB1107 significantly reduced plasma transaminases and liver Gal-3 and reduced liver fibrosis. RNAseq analysis of whole liver showed that 1,659 DEGs were identified with CCl4 treatment compared to control. Pathways enriched in up-regulated genes in the CCl4 group included those related to the extracellular matrix, collagen biosynthesis and assembly, cell cycle and the immune system. Comparing GB1107 treatment with CCl4 control 1147 DEGs were identified. GB1107 effectively reversed the majority of the CCl4 induced gene changes. Conclusions and ImplicationsGB1107 attenuated liver fibrosis and highlights Gal-3 as a therapeutic target for hepatic fibrosis.

The de-sulfinylation enzyme sulfiredoxin-1 attenuates hepatic stellate cell activation and liver fibrosis by modulating the PTPN12-NLRP3 axis.

Liver fibrosis is characterized by the progressive scarring of liver tissue. Oxidative stress is a critical causal factor of hepatic stellate cell (HSC) activation and the subsequent liver fibrogenesis, but the mechanism is not fully understood. Cysteine sulfinic acid (Cys-SO2H), a modification of reactive cysteine residues, is a unique form of oxidative response that alters the structure and function of proteins. Sulfiredoxin 1 (SRXN1) is responsible for ATP-dependent reduction of the Cys-SO2H to sulfenic acid (Cys-SOH). We found that the expression of SRXN1 was increased in activated HSCs and in human and mouse fibrotic livers. HSC-specific ablation of Srxn1 or pharmacological inhibition of Srxn1 exacerbated HSC activation and sensitized mice to liver fibrosis. Mechanistically, SRXN1 inhibited HSC activation by de-sulfinylating the phosphatase protein tyrosine phosphatase non-receptor type 12 (PTPN12), which enhanced its phosphatase activity and protein stability, leading to decreased tyrosine phosphorylation and reduced activation of the pro-fibrotic inflammasome protein NLRP3. The anti-fibrotic effect of SRXN1 was abolished when NLRP3 was inhibited. In contrast, overexpression of PTPN12 attenuated NLRP3 activation, and this effect was further amplified by the C164A S-sulfinylation resistant mutant of PTPN12. Our findings have uncovered an important role of SRXN1 and protein S-sulfinylation in HSC activation and liver fibrosis. The SRXN1-PTPN12-NLRP3 axis represents potential therapeutic targets for liver fibrosis.

LiMAx test and ultrasound elastography to measure biomarkers of declining liver function in patients with liver fibrosis: A correlation analysis.

Monitoring liver changes is crucial in the management of liver fibrosis. Current diagnostic methods include liver function tests such as the Liver Maximum Capacity (LiMAx) test and measurements of liver stiffness. While the LiMAx test quantifies liver function through 13C-methacetin metabolism, ultrasound (US) elastography noninvasively assesses liver stiffness. The relationship between the findings of these methods in patients with liver fibrosis is not fullyunderstood. This study evaluated the correlation between LiMAx measurements of liver function and US elastography-based liver stiffness measurements to better understand the interplay between functional and structural liver parameters in fibrotic liver disease. Additionally, the relationship between body mass index (BMI) and these parameters isevaluated. This retrospective study analysed data from 97 patients who underwent both LiMAx testing and real-time elastography, resulting in a total data set of 108 examinations. The correlations between the results of the LiMAx test and elastography and their relationships with body mass index (BMI) were analysed. There was a significant negative correlation (r = -0.25, p < 0.05) between LiMAx test values and liver stiffness measurements. BMI was significantly negatively correlated with LiMAx values (r = -0.29, p < 0.001) but not significantly correlated with liver stiffness values. This retrospective study confirms the results of previous studies showing a notable but weak association between liver function and liver stiffness. Our results highlight the potential value of both tests as complementary tools for the evaluation of liver health, reinforcing the necessity for a multimodal approach to liver assessment.

LHPP deficiency aggravates liver fibrosis through TGF-β/Smad3 signaling.

Liver fibrosis is characterized by a wound-healing response and may progress to liver cirrhosis and even hepatocellular carcinoma. Phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) is a tumor suppressor that participates in malignant diseases. However, the role of LHPP in liver fibrosis has not been determined. Herein, the function and regulatory network of LHPP were explored in liver fibrosis. The expression of LHPP in human and murine fibrotic liver tissues was assessed via immunohistochemistry and Western blot analysis. In addition, liver fibrosis was induced in wild-type (WT) and LHPP-/- (KO) mice after carbon tetrachloride (CCl4) or thioacetamide (TAA) treatment. The effect of LHPP was systematically assessed by using specimens acquired from the above murine models. The functional role of LHPP was further explored by detecting the pathway activity of TGF-β/Smad3 and apoptosis after interfering with LHPP invitro. To explore whether the function of LHPP depended on the TGF-β/Smad3 pathway invivo, an inhibitor of the TGF-β/Smad3 pathway was used in CCl4-induced WT and KO mice. LHPP expression was downregulated in liver tissue samples from fibrosis patients and fibrotic mice. LHPP deficiency aggravated CCl4- and TAA-induced liver fibrosis. Moreover, through immunoblot analysis, we identified the TGF-β/Smad3 pathway as a key downstream pathway of LHPP invivo and invitro. The effect of LHPP deficiency was reversed by inhibiting the TGF-β/Smad3 pathway in liver fibrosis. These results revealed that LHPP deficiency exacerbates liver fibrosis through the TGF-β/Smad3 pathway. LHPP may be a potential therapeutic target in hepatic fibrosis.

Kisspeptin Alleviates Human Hepatic Fibrogenesis by Inhibiting TGFβ Signaling in Hepatic Stellate Cells.

The peptide hormone kisspeptin attenuates liver steatosis, metabolic dysfunction-associated steatohepatitis (MASH), and fibrosis in mouse models by signaling via the kisspeptin 1 receptor (KISS1R). However, whether kisspeptin impacts fibrogenesis in the human liver is not known. We investigated the impact of a potent kisspeptin analog (KPA) on fibrogenesis using human precision-cut liver slices (hPCLS) from fibrotic livers from male patients, in human hepatic stellate cells (HSCs), LX-2, and in primary mouse HSCs. In hPCLS, 48 h and 72 h of KPA (3 nM, 100 nM) treatment decreased collagen secretion and lowered the expression of fibrogenic and inflammatory markers. Immunohistochemical studies revealed that KISS1R is expressed and localized to HSCs in MASH/fibrotic livers. In HSCs, KPA treatment reduced transforming growth factor b (TGFβ)-the induced expression of fibrogenic and inflammatory markers, in addition to decreasing TGFβ-induced collagen secretion, cell migration, proliferation, and colony formation. Mechanistically, KISS1R signaling downregulated TGFβ signaling by decreasing SMAD2/3 phosphorylation via the activation of protein phosphatases, PP2A, which dephosphorylates SMAD 2/3. This study revealed for the first time that kisspeptin reverses human hepatic fibrogenesis, thus identifying it as a new therapeutic target to treat hepatic fibrosis.

Berberine-Loaded PVCL-PVA-PEG Self-Assembled Micelles for the Treatment of Liver Fibrosis.

Liver fibrosis is a necessary pathological process in many chronic liver diseases. Studies have shown that the progression of chronic liver disease can be slowed by rational intervention in hepatic fibrosis. Berberine (BBR), a natural extract of Phellodendron amurense, inhibits the development of liver fibrosis through several mechanisms. However, the clinical application of BBR is limited due to its low solubility. Drug delivery systems have been developed to improve the solubility of hydrophobic drugs and increase their efficacy in treating the liver fibrosis. In this study, a biocompatible nanomicelle was constructed by thin-film dispersion method using polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (PVCL-PVA-PEG) as a carrier to encapsulate BBR (PVCL-PVA-PEG/BBR-MCs) to improve the solubility of BBR and reduce the systemic side effects. The ability to inhibit HSC-T6 cell activation of PVCL-PVA-PEG/BBR-MCs was evaluated in vitro. The anti-hepatic fibrosis effects of PVCL-PVA-PEG/BBR-MCs were investigated in vivo. PVCL-PVA-PEG/BBR-MCs have a uniform spherical shape with a mean particle size of 60.04 ± 0.027 nm and a potential of 1.49 ± 0.32 mV. It had an encapsulation efficiency of 98.52% ± 0.70 and drug loading content of 6.16% ± 0.04. Compared to free BBR, PVCL-PVA-PEG/BBR-MCs significantly inhibited HSC-T6 cell activation and TGF-β1-induced HSC-T6 cell migration in vitro. In vivo biodistribution experiments showed significantly improved hepatic distribution of PVCL-PVA-PEG/DiD-MCs compared to free DiD, suggesting that PVCL-PVA-PEG micelles enhance the ability of BBR to enter the liver and improve therapeutic efficacy. After treatment, PVCL-PVA-PEG/BBR-MCs significantly improved fibrotic liver structure and reduced collagen deposition in comparison to the CCl4-treated group; the treatment outcome was more effective than that of the free BBR group. Our results demonstrate the advantages of encapsulating BBR in PVCL-PVA-PEG micelles and highlight the potential of PVCL-PVA-PEG/BBR-MCs as a therapeutic strategy for the treatment of liver fibrosis.

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.

NADPH oxidase 4 deficiency promotes hepatocellular carcinoma arising from hepatic fibrosis by inducing M2-macrophages in the tumor microenvironment

Hepatocellular carcinoma (HCC) often arises in the cirrhotic livers, highlighting the intricate link between hepatic fibrosis and carcinogenesis. Reactive oxygen species produced by NADPH oxidase 4 (NOX4) contribute to liver injury leading to hepatic fibrosis. Paradoxically, NOX4 is known to inhibit HCC progression. This study aims to elucidate the role of NOX4 in hepatocarcinogenesis in the background of hepatic fibrosis. We established the mouse model of HCC arising from the fibrotic liver by administering diethylnitrosamine and carbon tetrachloride to wild-type (WT) or NOX4−/− mice. Hepatic fibrogenesis, tumorigenesis, and macrophage polarization were assessed by immunohistochemistry, PCR, and flow cytometry using in vivo and in vitro models. In NOX4−/− mice, hepatic fibrosis was attenuated, while the number of tumors and the proliferation of HCC cells were increased compared to WT mice. Notably, a significant increase in M2-polarized macrophages was observed in NOX4−/− mice through immunohistochemistry and PCR analysis. Subsequent experiments demonstrated that NOX4-silenced HCC cells promote macrophage polarization toward M2. In addition to attenuating hepatic fibrogenesis, NOX4 deficiency triggers macrophage polarization towards the M2 phenotype in the fibrotic liver, thereby promoting hepatocellular carcinogenesis. These findings provide novel insights into the mechanism of NOX4-mediated tumor suppression in HCC arising from fibrotic livers.

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.

Huangqi Decoction reduces liver fibrosis in rats by modulating PI3K/Akt/mTOR signaling and promoting autophagy.

Liver fibrosis is a chronic condition caused by various factors, and currently, there are no widely effective treatments. Autophagy plays a crucial role in maintaining liver energy homeostasis, and its disruption can contribute to the development of liver fibrosis. This study investigates the effects and molecular mechanisms of Huangqi Decoction, a traditional Chinese medicine, on autophagy and apoptosis in fibrotic liver tissue. Tissue staining indicated that Huangqi Decoction mitigated CCL4-induced liver injury and apoptosis in rats. Western blot analysis of liver fibrosis markers revealed that Huangqi Decoction significantly reduced the expression levels of alpha-smooth muscle actin (α-SMA), type I collagen, matrix metalloproteinase-2 (MMP-2), and matrix metalloproteinase-9 (MMP-9). Additionally, serum markers of liver fibrosis and biochemical indicators of hepatocyte injury showed that Huangqi Decoction effectively lowered serum levels of hyaluronic acid (HA), lymph node (LN), type I collagen, aspartate aminotransferase (AST), and alanine aminotransferase (ALT). Furthermore, Western blot analysis confirmed that Huangqi Decoction alleviated hepatocyte injury by promoting autophagy and inhibiting the PI3K/Akt/mTOR signaling pathway. In conclusion, Huangqi Decoction enhances autophagy and inhibits apoptosis through the PI3K/Akt/mTOR pathway in rats with liver fibrosis.

SIRT7 protects against liver fibrosis by suppressing stellate cell activation via TGF-β/SMAD2/3 pathway

BackgroundSIRT7 is a class III HDACs deacetylase which plays critical roles in various biological processes. Aberrant SIRT7 expression is associated with tumorigenesis and disease progression while role of SIRT7 in hepatic fibrosis remain elusive. MethodsSIRT7 expression was examined in fibrotic liver sample via WB and IHC. Myeloid cell-specific knockout (SIRT7MKO) mice were generated by crossing SIRT7flox/flox mice with LysM-Cre mice. Primary hepatic stellate cells (HSCs) was isolated to examine stellate cells activation. SIRT7 and SMAD2/3 interaction were analyzed by immunoprecipitation. SB525334 was used to prevent SMAD2/3 phosphorylation. ResultsSIRT7 expression was decreased during chronic liver disease progression but was increased in liver cancer. IHC staining indicated that SIRT7 was primarily expressed in non-parenchymal cells in both fibrotic and cirrhotic liver. Knockout SIRT7 in myeloid cells resulted in significant elevation of serum ALT and liver fibrosis, but mildly affected hepatic inflammation after CCl4 treatment. We further observed significant elevation of elevation of stellate cell activation and SMAD2/3 activation in SIRT7MKO mice. By using primary HSCs and stellate cell line, we confirmed that SIRT7 interacted with SMAD2/3, induced its deacetylation and was critical in regulation of SMAD2/3 activation and stellate cell activation upon TGF-β stimulation. Pharmacological inhibition of SMAD2/3 reversed the hyperactivation of SIRT7MKO HSCs after TGF-β stimulation, and abolished stellate cell activation and liver fibrosis in SIRT7MKO mice. ConclusionOur findings revealed previously unidentified role of SIRT7 in regulating HSCs activation via modulating TGF-β/SMAD2/3 signaling pathway. Targeting SIRT7 might offer novel therapeutic option against liver fibrosis.

Chitinase 1: a novel therapeutic target in metabolic dysfunction-associated steatohepatitis.

Metabolic dysfunction-associated steatohepatitis (MASH) is characterized by persistent inflammatory cascades, with macrophage activation playing a pivotal role. Chitinase 1 (CHIT1), produced by activated macrophages, is a key player in this cascade. In this study, we aimed to explore the role of CHIT1 in MASH with progressive liver fibrosis. Fibrotic liver tissue and serum from distinct patient groups were analyzed using nCounter MAX, flow cytometry, immunohistochemistry, and enzyme-linked immunosorbent assay. A MASH mouse model was constructed to evaluate the effectiveness of OATD-01, a chitinase inhibitor. Macrophage profiling was performed using single-nuclei RNA sequencing and flow cytometry. CHIT1 expression in fibrotic liver tissues was significantly correlated with the extent of liver fibrosis, macrophages, and inflammation. Single-nuclei RNA sequencing demonstrated a notable increase in macrophages numbers, particularly of lipid-associated macrophages, in MASH mice. Treatment with OATD-01 reduced non-alcoholic fatty liver disease activity score and Sirius red-positive area. Additionally, OATD-01-treated mice had lower CHIT1, F4/80, and α-smooth muscle actin positivity, as well as significantly lower levels of inflammatory markers, pro-fibrotic genes, and matrix remodeling-related mRNAs than vehicle-treated mice. Although the population of F4/80+CD11b+ intrahepatic mononuclear phagocytes remained unchanged, their infiltration and activation (CHIT1+MerTK+) significantly decreased in OATD-01-treated mice, compared with that observed in vehicle-treated mice. Our study underscores the pivotal role of CHIT1 in MASH. The observed significant improvement in inflammation and hepatic fibrosis, particularly at higher doses of the CHIT1 inhibitor, strongly suggests the potential of CHIT1 as a therapeutic target in MASH accompanied by progressive liver fibrosis.

Inhibition of ATP1V6G3 prompts hepatic stellate cell senescence with reducing ECM by activating Notch1 pathway to alleviate hepatic fibrosis

Liver fibrosis is characterized by an excessive reparative response to various etiological factors, with the activated hepatic stellate cells (aHSCs) leading to extracellular matrix (ECM) accumulation. Senescence is a stable growth arrest, and the senescence of aHSCs is associated with the degradation of ECM and the regression of hepatic fibrosis, making it a promising approach for managing hepatic fibrosis. The role and specific mechanisms by which V-Type Proton ATPase Subunit G 3 (ATP6V1G3) influences senescence in activated HSCs during liver fibrosis remain unclear. Our preliminary results reveal upregulation of ATP6V1G3 in both human fibrotic livers and murine liver fibrosis models. Additionally, ATP6V1G3 inhibition induced senescence in aHSCs in vitro. Moreover, suppressing Notch1 reversed the senescence caused by ATP6V1G3 inhibition in HSCs. Thus, targeting ATP6V1G3, which appears to drive HSCs senescence through the Notch1 pathway, emerges as a potential therapeutic strategy for hepatic fibrosis.

Neutrophil-secreted S100A8/A9 participates in fatty liver injury and fibrosis by promoting myofibroblast migration.

Fatty liver, which is induced by abnormal lipid metabolism, is one of the most common causes of chronic liver disease globally and causes liver fibrosis. During this process, bone marrow-derived mesenchymal stromal cells (BMSCs) and hepatic stellate cells (HSCs) migrate toward the injured liver and participate in fibrogenesis by transdifferentiating into myofibroblasts. S100A8/A9 is a powerful inducer of cell migration and is involved in liver injury. But there are few reports about the effects of S100A8/A9 on BMSC/HSC migration. In the current study, we found that S100A8/A9 expression was increased during fatty liver injury/fibrogenesis. Moreover, S100A8/A9 expression had a positive correlation with fibrosis marker gene expressions in the injured liver. S100A8/A9 was mainly produced by neutrophils in the fibrotic liver. In vitro, neutrophil-secreted S100A8/A9 promoted BMSC/HSC migration via remodeling of microfilaments. Using specific siRNA and inhibitor, we proved that S100A8/A9-induced BMSC/HSC migration is dependent on TLR4/Rho GTPases signaling. Moreover, S100A8/A9 knock-down alleviated liver injury and fibrogenesis in vivo, while injection of S100A9 neutralizing antibody performed similar roles. We proved that S100A8/A9 was involved in liver injury and fibrogenesis via inducing BMSC/HSC migration. Our research reveals a new mechanism underlying BMSC/HSC migration in liver fibrosis and suggests S100A8/A9 as a potential therapeutic target of liver fibrosis. KEY MESSAGES: S100A8/A9 is secreted by neutrophils and increased in fatty liver injury. Neutrophil-secreted S100A8/A9 is a mediator of BMSC/HSC migration in vitro. S100A8/A9-induced BMSC/HSC migration is dependent on TLR4/Rho GTPases signaling. S100A8/A9 blockade alleviates liver injury and fibrogenesis in vivo.

Fibrotic liver extracellular matrix induces cancerous phenotype in biomimetic micro-tissues of hepatocellular carcinoma model

BackgroundDespite considerable advancements in identifying factors contributing to the development of hepatocellular carcinoma (HCC), the pathogenesis of HCC remains unclear. In many cases, HCC is a consequence of prolonged liver fibrosis, resulting in the formation of an intricate premalignant microenvironment. The accumulation of extracellular matrix (ECM) is a hallmark of premalignant microenvironment. Given the critical role of different matrix components in regulating cell phenotype and function, this study aimed to elucidate the interplay between the fibrotic matrix and malignant features in HCC. MethodsLiver tissues from both control (normal) and carbon tetrachloride (CCl4)-induced fibrotic rats were decellularized using sodium dodecyl sulfate (SDS) and Triton X-100. The resulting hydrogel from decellularized ECM was processed into micro-particles via the water-in-oil emulsion method. Micro-particles were subsequently incorporated into three-dimensional liver biomimetic micro-tissues (MTs) comprising Huh-7 cells, human umbilical vein endothelial cells (HUVECs), and LX-2 cells. The MTs were evaluated using the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay at day 11, immunofluorescence staining, immunoblotting, and spheroid migration assay at day 14 after co-culture. ResultsFibrotic matrix from CCl4-treated rat livers significantly enhanced the growth rate of the MTs and their expression of CCND1 as compared to the normal one. Fibrotic matrix, also induced the expression of epithelial-to-mesenchymal transition (EMT)-associated genes such as TWIST1, ACTA2, MMP9, CDH2, and VIMENTIN in the MTs as compared to the normal matrix. Conversely, the expression of CDH1 and hepatic maturation genes HNF4A, ALB, CYP3A4 was decreased in the MTs when the fibrotic matrix was used. Furthermore, the fibrotic matrix increased the migration of the MTs and their secretion of alpha-fetoprotein. ConclusionsOur findings suggest a regulatory role for the fibrotic matrix in promoting cancerous phenotype, which could potentially accelerate the progression of malignancy in the liver.

FoxD1 expression identifies a distinct subset of hepatic stellate cells involved in liver fibrosis

Hepatic stellate cells (HSCs) are pericytes of the liver responsible for liver fibrosis and cirrhosis, which are the end stages of chronic liver diseases. TGF-β activates HSCs, leading to the differentiation of myofibroblasts in the process of liver fibrosis. While the heterogeneity of HSCs is appreciated in the fibrotic liver, it remains elusive which HSC subsets mainly contribute to fibrosis. Here, we show that the expression of the pericyte marker FoxD1 specifically marks a subset of HSCs in FoxD1-fate tracer mice. HSCs fate-mapped by FoxD1 were preferentially localized in the portal and peripheral areas of both the homeostatic and fibrotic liver induced by carbon tetrachloride. Furthermore, the deletion of Cbfβ, which is necessary for TGF-β signaling, in FoxD1-expressing cells ameliorated liver fibrosis. Thus, we identified an HSC subset that preferentially responds to liver injuries.