Role In Hepatic Fibrosis Research Articles

Cell-specific regulation of insulin action and hepatic fibrosis by CEACAM1.

The incidence of metabolic dysfunction-associated steatotic liver disease (MASLD) has reached an epidemic rise worldwide. The disease is a constellation of a broad range of metabolic and histopathologic abnormalities. It begins with hepatic steatosis and progresses to metabolic dysfunction-associated steatohepatitis (MASH), including hepatic fibrosis, apoptosis, and cell injury. Despite ample research effort, the pathogenesis of the disease has not been fully delineated. Whereas insulin resistance is implicated in the early stages of the disease, its role in hepatic fibrosis remains controversial. We have focused our studies on the role of carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) in hepatocytes and endothelial cells in the metabolic and histopathological dysregulation in MASH. Patients with MASH exhibit lower hepatic CEACAM1 with a progressive decline in hepatocytes and endothelial cells as the fibrosis stage advances. In mice, conditional deletion of CEACAM1 in hepatocytes impairs insulin clearance to cause hyperinsulinemia-driven insulin resistance with steatohepatitis and hepatic fibrosis even when mice are fed a regular chow diet. In contrast, its conditional deletion in endothelial cells causes inflammation-driven hepatic fibrosis without adversely affecting metabolism (mice remain insulin-sensitive and do not develop hepatic steatosis). Thus, this review provides in vivo evidence that supports or discards the role of insulin resistance in liver injury and hepatic fibrosis.

Formononetin Induces Ferroptosis in Activated Hepatic Stellate Cells to Attenuate Liver Fibrosis by Targeting NADPH Oxidase 4.

Ferroptosis is a newly discovered type of cell death that exerts a crucial role in hepatic fibrosis. Formononetin (FMN), a natural isoflavone compound mainly isolated from Spatholobus suberectus Dunn, shows multiple biological activities, including antioxidant, anti-inflammatory, and hepatoprotection. This research aims to explore the regulatory mechanism of FMN in liver fibrosis and the relationship between NADPH oxidase 4 (NOX4) and ferroptosis. The effects of FMN on HSC ferroptosis were evaluated in rat model of CCl4-induced hepatic fibrosis. In vitro, N-acetyl-L-cysteine (NAC) and deferoxamine (DFO) were used to block ferroptosis and then explored the anti-fibrotic effect of FMN. The target protein of FMN was identified by bio-orthogonal click chemistry reaction as well as drug affinity responsive target stability (DARTS), cellular thermal shift (CETSA), surface plasmon resonance (SPR) assays, and isothermal titration calorimetry (ITC) analysis. Here, we found that FMN exerted anti-fibrotic effects via inducing ferroptosis in activated HSCs. NAC and DFO prevented FMN-induced ferroptotic cell death and collagen reduction. Furthermore, FMN bound directly to NOX4 through possible active amino acid residues sites, and increased NOX4-based NADPH oxidase activity to enhance levels of NADP+/NADPH, thus promoting ferroptosis of activated HSCs and relieving liver fibrosis. These results demonstrate that the direct target and mechanism by which FMN improves liver fibrosis, suggesting that FMN may be a natural candidate for further development of liver fibrosis therapy.

Galectin 3-binding protein (LGALS3BP) depletion attenuates hepatic fibrosis by reducing transforming growth factor-β1 (TGF-β1) availability and inhibits hepatocarcinogenesis.

Increased Galectin 3-binding protein (LGALS3BP) serum levels have been used to assess hepatic fibrosis stages and the severity of hepatocellular carcinoma (HCC). Considering the crucial role of transforming growth factor-β1 (TGF-β1) in the emergence of these diseases, the present study tested the hypothesis that LGALS3BP regulates the TGF-β1 signaling pathway. The expression levels of LGALS3BP and TGFB1 were analyzed in patients with metabolic dysfunction-associated steatohepatitis (MASH) and HCC. Multiple omics techniques, such as RNA-sequencing, transposase-accessible chromatin-sequencing assay, and liquid chromatography-tandem mass spectrometry proteomics, were used to identify the regulatory mechanisms for the LGALS3BP-TGF-β1 axis. The effects of altered TGF-β1 signaling by LGALS3BP were investigated in conditional LGALS3BP-knockin and LGALS3BP-knockout mice. In patients with MASH and HCC, the levels of LGALS3BP and TGFB1 exhibited positive correlations. Stimulation of LGALS3BP by the inflammatory cytokine interferon α in HCC cells or ectopic overexpression of LGALS3BP in hepatocytes promoted the expression levels of TGFB1. Aggravated fibrosis was observed in the livers of hepatocyte-specific LGALS3BP-knockin mice, with increased TGFB1 levels. LGALS3BP directly bound to and assembled integrin αV, an integral mediator required for releasing active TGF-β1 from extracellular latent complex with the rearranged F-actin cytoskeleton. The released TGF-β1 activated JunB transcription factor, which in turn promoted the TGF-β1 positive feedback loop. LGALS3BP deletion in the hepatocytes downregulated TGF-β1 signaling and CCl4 induced fibrosis. Moreover, LGALS3BP depletion hindered hepatocarcinogenesis by limiting the availability of fibrogenic TGF-β1. LGALS3BP plays a crucial role in hepatic fibrosis and carcinogenesis by controlling the TGF-β1 signaling pathway, making it a promising therapeutic target in TGF-β1-related diseases.

An inducible sphingosine kinase 1 in hepatic stellate cells potentiates liver fibrosis

Hepatic stellate cells (HSCs) play a role in hepatic fibrosis and sphingosine kinase (SphK) is involved in biological processes. As studies on the regulatory mechanisms and functions of SphK in HSCs during liver fibrosis are currently limited, this study aimed to elucidate the regulatory mechanism and connected pathways of SphK upon HSC activation. The expression of SphK1 was higher in HSCs than in hepatocytes, and upregulated in activated primary HSCs. SphK1 was also increased in liver homogenates of carbon tetrachloride-treated or bile duct ligated mice and in transforming growth factor-β (TGF-β)-treated LX-2 cells. TGF-β-mediated SphK1 induction was due to Smad3 signaling in LX-2 cells. SphK1 modulation altered the expression of liver fibrogenesis-related genes. This SphK1-mediated profibrogenic effect was dependent on SphK1/sphingosine-1-phosphate/sphingosine-1-phosphate receptor signaling through ERK. Epigallocatechin gallate blocked TGF-β-induced SphK1 expression and hepatic fibrogenesis by attenuating Smad and MAPK activation. SphK1 induced by TGF-β facilitates HSC activation and liver fibrogenesis, which is reversed by epigallocatechin gallate. Accordingly, SphK1 and related signal transduction may be utilized to treat liver fibrosis.

Cysteine sulfenylation contributes to liver fibrosis via the regulation of EphB2-mediated signaling

Sulfenylation is a reversible oxidative posttranslational modification (PTM) of proteins on cysteine residues. Despite the dissection of various biological functions of cysteine sulfenylation, its roles in hepatic fibrosis remain elusive. Here, we report that EphB2, a receptor tyrosine kinase previously implicated in liver fibrosis, is regulated by cysteine sulfenylation during the fibrotic progression of liver. Specifically, EphB2 is sulfenylated at the residues of Cys636 and Cys862 in activated hepatic stellate cells (HSCs), leading to the elevation of tyrosine kinase activity and protein stability of EphB2 and stronger interactions with focal adhesion kinase for the activation of downstream mitogen-activated protein kinase signaling. The inhibitions of both EphB2 kinase activity and cysteine sulfenylation by idebenone (IDE), a marketed drug with potent antioxidant activity, can markedly suppress the activation of HSCs and ameliorate hepatic injury in two well-recognized mouse models of liver fibrosis. Collectively, this study reveals cysteine sulfenylation as a new type of PTM for EphB2 and sheds a light on the therapeutic potential of IDE for the treatment of liver fibrosis.

ACE2 Expressed on Myeloid Cells Alleviates Sepsis-Induced Acute Liver Injury via the Ang-(1-7)-Mas Receptor Axis.

Sepsis-induced acute liver injury (ALI) is common in intensive care units. Angiotensin-converting enzyme 2 (ACE2) plays a vital role in hepatic fibrosis and steatosis; however, its role in sepsis-induced ALI remains unclear. This study found that hepatic ACE2 expression in cecal ligation and puncture (CLP)-treated mice significantly decreased 24h after CLP. ACE2-transgenic (TG) mice exhibited a significant improvement in CLP-induced ALI, accompanied by the inhibition of hepatocyte apoptosis, oxidative stress, and inflammation, while ACE2-knockout mice demonstrated an opposite trend. During sepsis-induced ALI, ACE2-TG could also elevate the Ang-(1-7) and Mas receptor (MasR) levels in liver tissues. Interestingly, the MasR inhibitor A779 abrogated the favorable effects of ACE2 on CLP-induced ALI. In a bone marrow transplantation experiment, the ACE2-TG transplantation group showed significantly improved inflammation and liver dysfunction, less hepatocyte apoptosis, and reduced oxidative stress after CLP compared with the wild-type transplantation group. In contrast, the ACE2-knockout group showed poor inflammatory response and liver dysfunction, significantly more hepatocyte apoptosis, and elevated oxidative stress than the wild-type transplantation group after CLP. ACE2 protects against sepsis-induced ALI by inhibiting hepatocyte apoptosis, oxidative stress, and inflammation via the Ang-(1-7)-Mas receptor axis. Thus, targeting ACE2 may be a promising novel strategy for preventing and treating sepsis-induced ALI.

MANF brakes TLR4 signaling by competitively binding S100A8 with S100A9 to regulate macrophage phenotypes in hepatic fibrosis.

The mesencephalic astrocyte-derived neurotrophic factor (MANF) has been recently identified as a neurotrophic factor, but its role in hepatic fibrosis is unknown. Here, we found that MANF was upregulated in the fibrotic liver tissues of the patients with chronic liver diseases and of mice treated with CCl4. MANF deficiency in either hepatocytes or hepatic mono-macrophages, particularly in hepatic mono-macrophages, clearly exacerbated hepatic fibrosis. Myeloid-specific MANF knockout increased the population of hepatic Ly6Chigh macrophages and promoted HSCs activation. Furthermore, MANF-sufficient macrophages (from WT mice) transfusion ameliorated CCl4-induced hepatic fibrosis in myeloid cells-specific MANF knockout (MKO) mice. Mechanistically, MANF interacted with S100A8 to competitively block S100A8/A9 heterodimer formation and inhibited S100A8/A9-mediated TLR4-NF-κB signal activation. Pharmacologically, systemic administration of recombinant human MANF significantly alleviated CCl4-induced hepatic fibrosis in both WT and hepatocytes-specific MANF knockout (HKO) mice. This study reveals a mechanism by which MANF targets S100A8/A9-TLR4 as a "brake" on the upstream of NF-κB pathway, which exerts an impact on macrophage differentiation and shed light on hepatic fibrosis treatment.

Bone Morphogenetic Protein 13 Has Protumorigenic Effects on Hepatocellular Carcinoma Cells In Vitro.

Activated hepatic stellate cells (HSCs) play a key role in hepatic fibrosis and, thus, build the "soil" for hepatocarcinogenesis. Furthermore, HSCs are known to promote the progression of hepatocellular carcinoma (HCC), but the molecular mechanisms are only incompletely understood. Recently, we newly described the expression of bone morphogenetic protein 13 (BMP13) by HSCs in fibrotic liver tissue. In addition, BMP13 has mostly been studied in the context of cartilage and bone repair, but not in liver disease or cancer. Thus, we aimed to analyze the expression and function of BMP13 in HCC. Expression analyses revealed high BMP13-expression in activated human HSCs, but not in human HCC-cell-lines. Furthermore, analysis of human HCC tissues showed a significant correlation between BMP13 and α-smooth muscle actin (α-SMA), and immunofluorescence staining confirmed the co-localization of BMP13 and α-SMA, indicating activated HSCs as the cellular source of BMP13 in HCC. Stimulation of HCC cells with recombinant BMP13 increased the expression of the inhibitors of differentiation 1 (ID1) and 2 (ID2), which are known targets of BMP-signaling and cell-cycle promotors. In line with this, BMP13-stimulation caused an induced SMAD 1/5/9 and extracellular signal-regulated kinase (ERK) phosphorylation, as well as reduced expression of cyclin-dependent kinase inhibitors 1A (CDKN1A) and 2A (CDKN2A). Furthermore, stimulation with recombinant BMP13 led to increased proliferation and colony size formation of HCC cells in clonogenicity assays. The protumorigenic effects of BMP13 on HCC cells were almost completely abrogated by the small molecule dorsomorphin 1 (DMH1), which selectively blocks the intracellular kinase domain of ALK2 and ALK3, indicating that BMP13 acts via these BMP type I receptors on HCC cells. In summary, this study newly identifies stroma-derived BMP13 as a potential new tumor promotor in HCC and indicates this secreted growth-factor as a possible novel therapeutic target in HCC.

Hop-derived Humulinones Reveal Protective Effects in in vitro Models of Hepatic Steatosis, Inflammation and Fibrosis.

Nonalcoholic fatty liver disease (NAFLD) is emerging as leading cause of liver disease worldwide. Specific pharmacologic therapy for NAFLD is a major unmet medical need. Recently, iso-alpha acids, hop-derived bitter compounds in beer, have been shown to beneficially affect NAFLD pathology. Humulinones are further hop derived bitter acids particularly found in modern styles of beer. So far, biological effects of humulinones have been unknown. Here, we investigated the effect of humulinones in in vitro models for hepatic steatosis, inflammation and fibrosis. Humulinones dose-dependently inhibited fatty acid induced lipid accumulation in primary human hepatocytes. Humulinones reduced the expression of fatty acid uptake transporter CD36 and key enzymes of (de novo) lipid synthesis. Conversely, humulinones increased the expression of FABP1, CPT1 and ACOX1, indicative for increased lipid combustion. Furthermore, humulinones ameliorated steatosis induced pro-inflammatory gene expression. Furthermore, humulinones significantly reduced the expression of pro-inflammatory and pro-fibrogenic factors in control as well as lipopolysaccharide treated activated hepatic stellate cells, which play a key role in hepatic fibrosis. In conclusion, humulinones beneficially affect different pathophysiological steps of NAFLD. Our data suggest humulinones as promising therapeutic agents for the prevention and treatment of NAFLD.

Gomisin D alleviates liver fibrosis through targeting PDGFRβ in hepatic stellate cells

Platelet-derived growth factor receptor β (PDGFRβ) plays an important role in hepatic fibrosis and is closely associated with hepatic stellate cells (HSCs) activation. Previously, by modeling PDGFRβ affinity chromatography, we found that gomisin D can target PDGFRβ. However, whether gomisin D has anti-fibrosis effects through targeting PDGFRβ remained unclear. In this study, the effect of gomisin D on hepatic fibrosis was evaluated in vivo and vitro. HSC cell lines and primary HSC were cultured and functionally we found that gomisin D promotes HSC apoptosis, inhibits HSCs activation and proliferation. A male BALB/c mouse liver fibrosis model was established to comfirm gomisin D (especially in 50 mg/kg) could improve liver fibrosis by inhibiting HSCs activation. In addition, gomisin D had a good binding ability with PDGFRβ (KD = 3.3e-5 M). Mechanically, gomisin D regulated PDGF-BB/PDGFRβ signaling pathway by targeting PDGFRβ, further more inhibited HSC activation, subsequently inhibited inflammatory factors, ultimately improved CCl4-induced liver fibrosis. Overall, gomisin D could inhibit HSC proliferation and activation, promote HSC apoptosis, and alleviate CCl4-induced hepatic fibrosis by targeting PDGFRβ and regulating PDGF-BB/PDGFRβ signaling pathway. This study provides a new drug for anti-liver firbosis therapy, and elucidates the deeper mechanism of gomisin D against HSCs activation by targeting PDGFRβ.

Inhibition of circular RNA ASPH reduces the proliferation and promotes the apoptosis of hepatic stellate cells in hepatic fibrosis

Circular RNAs (circRNAs) are a newly identified form of non-coding RNA that play a crucial role in various pathological processes. However, the expression profile and function of circRNAs in hepatic fibrosis (HF) remain largely unknown. In this study, we showed that a novel circRNA ASPH (circASPH) mediates HF by targeting the miR-139-5p/Notch1 axis. We investigated the expression profile of circRNAs in hepatocyte exosomes of mice with HF using circRNA-sequencing and found significant upregulation of circASPH. Loss- and gain-of-function analysis of circASPH was performed to assess its role in HF. Furthermore, we performed luciferase reporter assay, RNA pull-down, and fluorescence in situ hybridization analyses and confirmed that circASPH directly binds to miR-139-5p. We also found that circASPH was upregulated in liver fibrogenesis. Downregulation of circASPH expression inhibited hepatic stellate cell (HSC) activation and proliferation, induced apoptosis, and attenuated mouse liver fibrogenic injury. Mechanistically, circASPH directly targeted miR-139-5p to regulate the expression of Notch1 in HF. Thus, downregulation of circASPH may suppress the activation of HSCs and HF through the circASPH/miR-139-5p/Notch1 axis. Our findings indicated that circASPH may be a potential biomarker for HF diagnosis and therapy.

Jiawei Taohe Chengqi Decoction attenuates hepatic fibrosis by preventing activation of HSCs through regulating Src/ERK/Smad3 signal pathway

Ethnopharmacological relevanceJiawei Taohe Chengqi Decoction (JTCD) is a Traditional Chinese Medicine (TCM) formula modified from Taohe Chengqi Decoction in the classic ancient literature of TCM “Treatise on Febrile Diseases”. Clinical and pharmacological studies have shown that JTCD has a therapeutic effect on hepatic encephalopathy, non-alcoholic fatty liver, cirrhotic ascites, and can alleviate acute liver injury in rats. Our previous studies confirmed that JTCD could alleviate hepatic fibrosis and activation of hepatic stellate cells (HSCs). However, its mechanism remains unclear. Aim of the studyThis study aimed to elucidate the mechanism of Src Signal on hepatic fibrosis and HSCs activation, and whether JTCD inhibited hepatic fibrosis and HSCs activation through affecting Src Signal. Materials and methodsIn vivo, sixty specific pathogen free male C57/BL6 mice were divided into following six groups: Control group, Model group, SARA group, JTCD low dose group, JTCD medium dose group and JTCD high dose group. Then we established a carbon tetrachloride (CCL4)-induced hepatic fibrosis mice model, each JTCD group was given the corresponding dose of JTCD by gavage, the SARA group was given Saracatinib and the control group was given saline, once a day for 4 consecutive weeks. UPLC-Q-TOF-MS analyzed chemical components of JTCD. Pathological examination including Hematoxylin and Eosin (H&E), Masson and Sirius red staining was used to observe the characteristic of hepatic fibrosis. Automatic biochemical analyzer detected the levels of alanine aminotransfease (ALT), and aspartate transaminase (AST) in serum. Western-blot and immunohistochemical staining (IHC) detected protein expression. In vitro, we used shRNA to knock down the expression of Src in immortalized human hepatic stellate cell line (LX-2), then intervened with ERK1/2 agonists/inhibitors and JTCD-containing serum after transforming growth factor β1 (TGF-β1) treatment. Immunofluorescence and western-blot detected protein expression. The migratory characteristic of HSCs was assessed by wound-healing assay. ResultsWe identified 135 chemical components in the water extract of JTCD, and the water extract of JTCD contains a variety of anti-hepatic fibrosis components. Compared to the model group, hepatic fibrosis performance was significantly improved, the serum levels of ALT and AST were significantly decreased in JTCD groups and SARA group, IHC staining and western blot results indicated that JTCD decreased the expressions of α-smooth muscle actin (α-SMA), phospho-Src (Tyr416), phospho-ERK1/2 and phospho-Smad3. In vitro, JTCD-containing serum could significantly decrease the protein expressions of α-SMA, phospho-Src (Tyr416), phospho-ERK1/2 and phospho-Smad3 according to the results of western-blot and immunofluorescence, in addition, JTCD-containing serum inhibited the mobility and activation of LX-2. What's more, after intervening with Src-shRNA, ERK1/2 agonists/inhibitors and JTCD-containing serum, the western-blot results showed that Src/ERK/Smad3 signal has an important role in hepatic fibrosis and HSCs, and JTCD attenuates hepatic fibrosis by preventing activation of HSCs through regulating Src/ERK/Smad3 signal pathway. ConclusionsThe results showed that Src kinase promoted hepatic fibrosis and HSCs activation through the ERK/Smad3 signal pathway. More importantly, the mechanism by which JTCD attenuated hepatic fibrosis and HSCs activation was by inhibiting the Src/ERK/Smad3 signal pathway.

Implications of differential transcription start site selection on chronic myeloid leukemia and prostate cancer cell protein expression.

The relevance of minor transcription start sites in broad promoters is not well understood. We have studied AGAP2 expression in prostate cancer and chronic myeloid leukemia (CML), showing transcription is initiated from alternative transcription start sites (TSSs) within a single TSS cluster, producing cancer-type-specific AGAP2 mRNAs with small differences in their 5' UTR length. Interestingly, in the CML cell lines where the 5' UTR is longer, AGAP2 protein levels are lower. We demonstrate that the selection of an upstream TSS involved the formation of a G quadruplex in the 5' UTR, decreasing polysome formation. After developing a bioinformatics pipeline to query data from the FANTOM project and the NCl-60 human tumor cell lines screen, we found HK1 expression can also be regulated by the same mechanism. Overall, we present compelling data supporting TSS selection within a TSS cluster play a role in protein expression and should not be ignored.

Identification of Liver Fibrosis-Related MicroRNAs in Human Primary Hepatic Stellate Cells Using High-Throughput Sequencing

MicroRNAs (miRNAs) participate in hepatic stellate cell (HSC) activation, which drives liver fibrosis initiation and progression. We aimed to identify novel hepatic fibrosis targets using miRNA sequencing (miRNA-seq) of human primary HSCs. Surgically resected liver tissues were used to extract HSCs. Based on next-generation sequencing, miRNA-seq was performed on four pairs of HSCs before and after in vitro culture. Additionally, we compared our data with open access miRNA-seq data derived from fourteen cirrhotic and nine healthy liver tissues. Selected miRNAs associated with fibrosis were verified by quantitative real-time PCR. Target mRNAs of differentially expressed (DE) miRNAs were predicted to construct co-expression networks. We identified 230 DEmiRNAs (118 upregulated and 112 downregulated) upon HSC activation. Of the 17 miRNAs with the most significant differences in expression, liver disease-related miRNAs included miR-758-3p, miR-493-5p, miR-409-3p, miR-31-5p, miR-1268a, and miR-381-3p, which might play roles in hepatic fibrosis. Moreover, let-7g-5p, miR-107, miR-122-5p, miR-127-3p, miR-139-5p, miR-148a-3p, miR-194-5p, miR-215-5p, miR-26a-5p, miR-340-5p, miR-451a, and miR-99a-5p were common between our data and the publicly available sequencing data. A co-expression network comprising 1891 matched miRNA-mRNA pairs representing 138 DEmiRNAs and 1414 DEmRNAs was constructed. MiR-1268a and miR-665, possessing the richest target DEmRNAs, may be vital in HSC activation. The targeted genes were involved in collagen metabolism, extracellular matrix structural constituent, cytoskeletal protein binding, and cell adhesion. The miRNAs we identified may provide a basis and reference for the selection of diagnostic and therapeutic targets for hepatic fibrosis.

20-Hydroxytetraenoic acid induces hepatic fibrosis via the TGF-β1/Smad3 signaling pathway

Hepatic fibrosis is caused by excessive accumulation of extracellular matrix (ECM) due to repeated liver injury. Hepatic stellate cells (HSCs) play a key role in the pathogenesis and progression of hepatic fibrosis. A study showed that CYP4A14 gene defect can inhibit hepatic fibrosis, but the specific mechanism was not clear. In this experiment, patients with hepatic fibrosis, LX-2 cells (a human HSCs line), and mice with liver fibrosis induced by carbon tetrachloride (CCl4) were used to study the effect of 20-Hydroxytetraenoic acid (20-HETE), one of the main metabolites of arachidonic acid (AA) catalyzed by CYP4A enzyme, on hepatic fibrosis and its mechanism. Our experimental results showed that the 20-HETE of patients with hepatic fibrosis is significantly higher than that of normal people and is closely related to the degree of fibrosis. 20-HETE could induce activation of LX-2 cells and 20-HETE antagonist could inhibit the induction of 20-HETE. 20-HETE was significantly increased in CCl4-induced liver fibrosis mice and inhibition of 20-HETE production could attenuate hepatic fibrosis. 20-HETE induced hepatic fibrosis mainly via the TGF- β1/Smad3 signal pathway. In conclusion, the results suggest that 20-HETE plays an important role in hepatic fibrosis and may be a possible target for the clinical treatment of hepatic fibrosis.

Transient Receptor Potential Vanilloid-1 (TRPV1) Alleviates Hepatic Fibrosis via TGF-β Signaling.

Hepatic fibrosis is a major global health problem and considered a leading cause of liver-related morbidity and mortality worldwide. Although previous studies have suggested that transient receptor potential vanilloid-1 (TRPV1) is protective against cardiac and renal fibrosis, its functional role in hepatic fibrosis has remained elusive. Herein, we characterize the effects of TRPV1 on carbon tetrachloride- (CCl4-) induced mice, in vitro transforming growth factor-β- (TGF-β-) treated hepatic stellate cells (HSCs), and human fibrosis specimens. Finally, our results demonstrated the significant TRPV1 downregulation in human liver fibrosis tissues. Knocking out TRPV1 significantly increased the expression of various hepatic fibrosis markers, while the expression of these biomarkers declined markedly in capsaicin-activated mice. Moreover, our study revealed that knocking down TRPV1 would enhance the promotive effect of TGF-β on HSC proliferation, cell cycle, cell apoptosis, and ECM expression. Also, such promotive effect can be partially reversible by capsaicin, an exogenous activator of TRPV1. Collectively, the obtained data suggest that TRPV1 may alleviate CCl4-induced hepatic fibrosis and attenuate the effect of TGF-β on HSC activation, proliferation, and apoptosis, which overall implies that targeting TRPV1 channel activity may be an effective therapeutic strategy for treating hepatic fibrosis.

FRI208 - Autoantibodies to apolipoprotein A-1 in chronic hepatitis C infection: a role in hepatic fibrosis and cirrhosis?

FRI208 - Autoantibodies to apolipoprotein A-1 in chronic hepatitis C infection: a role in hepatic fibrosis and cirrhosis?

Crosstalk Between Autophagy and Innate Immunity: A Pivotal Role in Hepatic Fibrosis.

Liver fibrosis is a repair process of chronic liver injuries induced by toxic substances, pathogens, and inflammation, which exhibits a feature such as deposition of the extracellular matrix. The initiation and progression of liver fibrosis heavily relies on excessive activation of hepatic stellate cells (HSCs). The activated HSCs express different kinds of chemokine receptors to further promote matrix remodulation. The long-term progression of liver fibrosis will contribute to dysfunction of the liver and ultimately cause hepatocellular carcinoma. The liver also has abundant innate immune cells, including DCs, NK cells, NKT cells, neutrophils, and Kupffer cells, which conduct complicated functions to activation and expansion of HSCs and liver fibrosis. Autophagy is one specific type of cell death, by which the aberrantly expressed protein and damaged organelles are transferred to lysosomes for further degradation, playing a crucial role in cellular homeostasis. Autophagy is also important to innate immune cells in various aspects. The previous studies have shown that dysfunction of autophagy in hepatic immune cells can result in the initiation and progression of inflammation in the liver, directly or indirectly causing activation of HSCs, which ultimately accelerate liver fibrosis. Given the crosstalk between innate immune cells, autophagy, and fibrosis progression is complicated, and the therapeutic options for liver fibrosis are quite limited, the exploration is essential. Herein, we review the previous studies about the influence of autophagy and innate immunity on liver fibrosis and the molecular mechanism to provide novel insight into the prevention and treatment of liver fibrosis.

Exosome-mediated delivery of RBP-J decoy oligodeoxynucleotides ameliorates hepatic fibrosis in mice.

Rationale: Macrophages play multi-dimensional roles in hepatic fibrosis. Studies have implicated Notch signaling mediated by the transcription factor RBP-J in macrophage activation and plasticity. Additionally, we have previously shown that myeloid-specific disruption of RBP-J can ameliorate hepatic fibrosis in mice. Accordingly, we next asked whether blocking Notch signaling in macrophages could serve as a therapeutic strategy to treat hepatic fibrosis. In this study, we used a combination of transcription factor decoy oligodeoxynucleotides (ODNs) and exosomes to test this possibility.Methods: Hairpin-type decoy oligodeoxynucleotides (ODNs) were designed for the transcription factor RBP-J. The effects of RBP-J decoy ODNs on Notch signaling were evaluated by western blot, quantitative RT-PCR, luciferase reporter assays, and electrophoretic mobility shift assays. ODNs were loaded into HEK293T-derived exosomes by electroporation. A hepatic fibrosis mouse model was established by the intraperitoneal injection of carbon tetrachloride or bile duct ligation. Mice with hepatic fibrosis were administered exosomes loaded with RBP-J decoy ODNs via tail vein injection. The in vivo distribution of exosomes was analyzed by fluorescence labeling and imaging. Liver histology was examined using hematoxylin and eosin, Sirius red, and Masson staining, as well as immunohistochemical staining for Col1α1 and αSMA.Results: We found that RBP-J decoy ODNs could be efficiently loaded into exosomes and inhibit the activation of Notch signaling. Furthermore, exosomes administered via the tail vein were found to be primarily taken up by hepatic macrophages in mice with liver fibrosis. Importantly, RBP-J decoy ODNs delivered by exosomes could efficiently inhibit Notch signaling in macrophages and ameliorate hepatic fibrosis in mice.Conclusions: Combined, our data showed that the infusion of exosomes loaded with RBP-J decoy ODNs represents a promising therapeutic strategy for the treatment of hepatic fibrosis.

LncRNA MEG3 modulates hepatic stellate cell activation by sponging miR‑145 to regulate PPARγ.

It is important to determine the mechanism of liver fibrosis for targeted therapy and the development of targeted therapies for liver fibrosis may offer promise for patients with liver disease. Long non-coding RNAs (lncRNAs) serve a role in hepatic fibrosis. The lncRNA maternally expressed gene 3 (MEG3) has been confirmed to inhibit liver fibrosis. The present study investigated the role of the MEG3 in healthy patients and patients with liver fibrosis. The expression levels of MEG3 and microRNA (miR)-145 in the serum of healthy volunteers and patients with liver fibrosis and in LX-2 cells were detected using reverse transcription-quantitative PCR. A dual-luciferase reporter assay was used to determine the targeting relationship between MEG3 and miR-145, and the targeting relationship between miR-145 and peroxisome proliferator-activated receptor γ (PPARγ). The protein expression levels of PPARγ, α-smooth muscle actin (α-SMA) and collagen I (COL1A1) were detected using western blotting. The expression levels of α-SMA and COL1A1 were also determined using immunofluorescence. Finally, a Cell Counting Kit-8 assay was performed to assess the proliferative ability of LX-2 cells. A significantly reduced MEG3 expression level was demonstrated in serum from patients with liver fibrosis compared with serum from healthy controls. TGF-β1 induced a significantly decreased MEG3 expression level in LX-2 human hepatic stellate cells in vitro. The TGF-β1-induced increases in cell proliferation and α-SMA and COL1A1 protein expression levels were reversed following MEG3 overexpression. The results also demonstrated that MEG3 sponged miR-145 and competed endogenously with miR-145 to regulate PPARγ. In summary, the present study identified MEG3 as an anti-fibrotic lncRNA and provided new information regarding the role of MEG3 in liver fibrosis. MEG3 may therefore be a potential target in the treatment of liver fibrosis.