Semaphorin 3C (Sema3C) reshapes stromal microenvironment to promote hepatocellular carcinoma progression.

More than 90% of hepatocellular carcinoma (HCC) cases develop in the presence of fibrosis or cirrhosis, making the tumor microenvironment (TME) of HCC distinctive due to the intricate interplay between cancer-associated fibroblasts (CAFs) and cancer stem cells (CSCs), which collectively regulate HCC progression. However, the mechanisms through which CSCs orchestrate the dynamics of the tumor stroma during HCC development remain elusive. Our study unveils a significant upregulation of Sema3C in fibrotic liver, HCC tissues, peripheral blood of HCC patients, as well as sorafenib-resistant tissues and cells, with its overexpression correlating with the acquisition of stemness properties in HCC. We further identify NRP1 and ITGB1 as pivotal functional receptors of Sema3C, activating downstream AKT/Gli1/c-Myc signaling pathways to bolster HCC self-renewal and tumor initiation. Additionally, HCC cells-derived Sema3C facilitated extracellular matrix (ECM) contraction and collagen deposition in vivo, while also promoting the proliferation and activation of hepatic stellate cells (HSCs). Mechanistically, Sema3C interacted with NRP1 and ITGB1 in HSCs, activating downstream NF-kB signaling, thereby stimulating the release of IL-6 and upregulating HMGCR expression, consequently enhancing cholesterol synthesis in HSCs. Furthermore, CAF-secreted TGF-ß1 activates AP1 signaling to augment Sema3C expression in HCC cells, establishing a positive feedback loop that accelerates HCC progression. Notably, blockade of Sema3C effectively inhibits tumor growth and sensitizes HCC cells to sorafenib in vivo. In sum, our findings spotlight Sema3C as a novel biomarker facilitating the crosstalk between CSCs and stroma during hepatocarcinogenesis, thereby offering a promising avenue for enhancing treatment efficacy and overcoming drug resistance in HCC.

A20 in hepatic stellate cells suppresses chronic hepatitis by inhibiting DCLK1-JNK pathway-dependent chemokines.

Hepatic stellate cells (HSCs) are responsible for liver fibrosis accompanied by its activation into myofibroblasts and the abundant production of extracellular matrix. However, the HSC contribution to progression of liver inflammation has been less known. We aimed to elucidate the mechanism in HSCs underlying the inflammatory response and the function of tumor necrosis factor α-related protein A20 (TNFAIP3). We established A20 conditional knockout (KO) mice crossing Twist2-Cre and A20 floxed mice. Using these mice, the effect of A20 was analyzed in mouse liver and HSCs. The human HSC line LX-2 was also used to examine the role and underlying molecular mechanism of A20. In this KO model, A20 was deficient in >80% of HSCs. Spontaneous inflammation with mild fibrosis was found in the liver of the mouse model without any exogenous agents, suggesting that A20 in HSCs suppresses chronic hepatitis. Comprehensive RNA sequence analysis revealed that A20-deficient HSCs exhibited an inflammatory phenotype and abnormally expressed chemokines. A20 suppressed JNK pathway activation in HSCs. Loss of A20 function in LX-2 cells also induced excessive chemokine expression, mimicking A20-deficient HSCs. A20 overexpression suppressed chemokine expression in LX-2. In addition, we identified DCLK1 in the genes regulated by A20. DCLK1 activated the JNK pathway and upregulates chemokine expression. DCLK1 inhibition significantly decreased chemokine induction by A20-silencing, suggesting that A20 controlled chemokine expression in HSCs via the DCLK1-JNK pathway. In conclusion, A20 suppresses chemokine induction dependent on the DCLK1-JNK signaling pathway. These findings demonstrate the therapeutic potential of A20 and the DCLK1-JNK pathway for the regulation of inflammation in chronic hepatitis.

Advances in Research on the Effectiveness and Mechanism of Active Ingredients from Traditional Chinese Medicine in Regulating Hepatic Stellate Cells Autophagy Against Hepatic Fibrosis.

Hepatic fibrosis (HF) is a pathological process of structural and functional impairment of the liver and is a key component in the progression of chronic liver disease. There are no specific anti-hepatic fibrosis (anti-HF) drugs, and HF can only be improved or prevented by alleviating the cause. Autophagy of hepatic stellate cells (HSCs) is closely related to the development of HF. In recent years, traditional Chinese medicine (TCM) has achieved good therapeutic effects in the prevention and treatment of HF. Several active ingredients from TCM (AITCM) can regulate autophagy in HSCs to exert anti-HF effects through different pathways, but relevant reviews are lacking. This paper reviewed the research progress of AITCM regulating HSCs autophagy against HF, and also discussed the relationship between HSCs autophagy and HF, pointing out the problems and limitations of the current study, in order to provide references for the development of anti-HF drugs targeting HSCs autophagy in TCM. By reviewing the literature in PubMed, Web of Science, Embase, CNKI and other databases, we found that the relationship between autophagy of HSCs and HF is currently controversial. HSCs autophagy may promote HF by consuming lipid droplets (LDs) to provide energy for their activation. However, in contrast, inducing autophagy in HSCs can exert the anti-HF effect by stimulating their apoptosis or senescence, reducing type I collagen accumulation, inhibiting the extracellular vesicles release, degrading pro-fibrotic factors and other mechanisms. Some AITCM inhibit HSCs autophagy to resist HF, with the most promising direction being to target LDs. While, others induce HSCs autophagy to resist HF, with the most promising direction being to target HSCs apoptosis. Future research needs to focus on cell targeting research, autophagy targeting research and in vivo verification research, and to explore the reasons for the contradictory effects of HSCs autophagy on HF.

Combination of Pirfenidone and Andrographolide Ameliorates Hepatic Stellate Cell Activation and Liver Fibrosis by Mediating TGF-ß/Smad Signaling Pathway.

Background: Biliary atresia (BA) is a devastating congenital disease characterized by inflammation and progressive liver fibrosis. Activation of hepatic stellate cells (HSCs) plays a central role in the pathogenesis of hepatic fibrosis. Our study aimed to investigate the pharmacological effect and potential mechanism of pirfenidone (PFD) and andrographolide (AGP) separately and together on liver fibrosis of BA. Materials and Methods: The bile ducts of male C57BL/6J mice were ligated or had the sham operation. The in vivo effects of PFD and/or AGP on liver fibrosis of BA were evaluated. Human hepatic stellate cells (LX-2) were also treated with PFD and/or AGP in vitro. Results: PFD and/or AGP ameliorates liver fibrosis and inflammation in the mice model of BA, as evidenced by significant downregulated in the accumulation of collagen fibers, hepatic fibrosis markers (α-SMA, collagen I, and collagen IV), and inflammatory markers (IL-1ß, IL-6, and TNF-α). Moreover, compared with monotherapy, these changes are more obvious in the combined treatment of PFD and AGP. Consistent with animal experiments, hepatic fibrosis markers (α-SMA, collagen I, and CTGF) and inflammatory markers (IL-1ß, IL-6, and TNF-α) were significantly decreased in activated LX-2 cells after PFD and/or AGP treatment. In addition, PFD and/or AGP inhibited the activation of HSCs by blocking the TGF-ß/Smad signaling pathway, and the combined treatment of PFD and AGP synergistically inhibited the phosphorylation of Smad2 and Smad3. Conclusion: The combined application of PFD and AGP exerted superior inhibitive effects on HSC activation and liver fibrosis by mediating the TGF-ß/Smad signaling pathway as compared to monotherapy. Therefore, the combination of PFD and AGP may be a promising treatment strategy for liver fibrosis in BA.

Glycolysis in hepatic stellate cells coordinates fibrogenic extracellular vesicle release spatially to amplify liver fibrosis.

Liver fibrosis is characterized by the activation of perivascular hepatic stellate cells (HSCs), the release of fibrogenic nanosized extracellular vesicles (EVs), and increased HSC glycolysis. Nevertheless, how glycolysis in HSCs coordinates fibrosis amplification through tissue zone-specific pathways remains elusive. Here, we demonstrate that HSC-specific genetic inhibition of glycolysis reduced liver fibrosis. Moreover, spatial transcriptomics revealed a fibrosis-mediated up-regulation of EV-related pathways in the liver pericentral zone, which was abrogated by glycolysis genetic inhibition. Mechanistically, glycolysis in HSCs up-regulated the expression of EV-related genes such as Ras-related protein Rab-31 (RAB31) by enhancing histone 3 lysine 9 acetylation on the promoter region, which increased EV release. Functionally, these glycolysis-dependent EVs increased fibrotic gene expression in recipient HSC. Furthermore, EVs derived from glycolysis-deficient mice abrogated liver fibrosis amplification in contrast to glycolysis-competent mouse EVs. In summary, glycolysis in HSCs amplifies liver fibrosis by promoting fibrogenic EV release in the hepatic pericentral zone, which represents a potential therapeutic target.

Hemodialysis bilayer bionic blood vessels developed by the mechanical stimulation of hepatitis B viral X(HBX) gene- transfected hepatic stellate cells. / é€šè¿‡æœºæ¢°åŠ›åˆºæ¿€ä¹™åž‹è‚ç‚Žç— æ¯’XåŸºå› (HBX)转染的肝星状细胞制备血液透析用双层仿生血管.

Artificial vascular graft (AVG) fistula is widely used for hemodialysis treatment in patients with renal failure. However, it has poor elasticity and compliance, leading to stenosis and thrombosis. The ideal artificial blood vessel for dialysis should replicate the structure and components of a real artery, which is primarily maintained by collagen in the extracellular matrix (ECM) of arterial cells. Studies have revealed that in hepatitis B virus (HBV)-induced liver fibrosis, hepatic stellate cells (HSCs) become hyperactive and produce excessive ECM fibers. Furthermore, mechanical stimulation can encourage ECM secretion and remodeling of a fiber structure. Based on the above factors, we transfected HSCs with the hepatitis B viral X (HBX) gene for simulating the process of HBV infection. Subsequently, these HBX-HSCs were implanted into a polycaprolactone-polyurethane (PCL-PU) bilayer scaffold in which the inner layer is dense and the outer layer consists of pores, which was mechanically stimulated to promote the secretion of collagen nanofiber from the HBX-HSCs and to facilitate crosslinking with the scaffold. We obtained an ECM-PCL-PU composite bionic blood vessel that could act as access for dialysis after decellularization. Then, the vessel scaffold was implanted into a rabbit's neck arteriovenous fistula model. It exhibited strong tensile strength and smooth blood flow and formed autologous blood vessels in the rabbit's body. Our study demonstrates the use of human cells to create biomimetic dialysis blood vessels, providing a novel approach for creating clinical vascular access for dialysis.

Human iPSC-derived liver co-culture spheroids to model liver fibrosis.

The lack of adequate humanin vitromodels that recapitulate the cellular composition and response of the human liver to injury hampers the development of anti-fibrotic drugs. The goal of this study was to develop a human spheroid culture model to study liver fibrosis by using induced pluripotent stem cell (iPSC)-derived liver cells. iPSCs were independently differentiated towards hepatoblasts (iHepatoblasts), hepatic stellate cells (iHSCs), endothelial cells (iECs) and macrophages (iMΦ), before assembly into free floating spheroids by culturing cells in 96-well U-bottom plates and orbital shaking for up to 21 days to allow further maturation. Through transcriptome analysis, we show further maturation of iECs and iMΦ, the differentiation of the iHepatoblasts towards hepatocyte-like cells (iHeps) and the inactivation of the iHSCs by the end of the 3D culture. Moreover, these cultures display a similar expression of cell-specific marker genes (CYP3A4, PDGFRß, CD31andCD68) and sensitivity to hepatotoxicity as spheroids made using freshly isolated primary human liver cells. Furthermore, we show the functionality of the iHeps and the iHSCs by mimicking liver fibrosis through iHep-induced iHSC activation, using acetaminophen. In conclusion, we have established a reproducible human iPSC-derived liver culture model that can be used to mimic fibrosisin vitroas a replacement of primary human liver derived 3D models. The model can be used to investigate pathways involved in fibrosis development and to identify new targets for chronic liver disease therapy.

Aggregation-Induced Emission CN-Based Nanoparticles to Alleviate Hypoxic Liver Fibrosis via Triggering HSC Ferroptosis and Enhancing Photodynamic Therapy.

Hypoxia can lead to liver fibrosis and severely limits the efficacy of photodynamic therapy (PDT). Herein, carbon nitride (CN)-based hybrid nanoparticles (NPs) VPSGCNs@TSI for light-driven water splitting were utilized to solve this problem. CNs were doped with selenide glucose (Se-glu) to enhance their red/NIR region absorption. Then, vitamin A-poly(ethylene glycol) (VA-PEG) fragments and aggregation-induced emission (AIE) photosensitizers TSI were introduced into Se-glu-doped CN NPs (VPSGCNs) to construct VPSGCNs@TSI NPs. The introduction of VA-PEG fragments enhanced the targeting of the NPs to activated hepatic stellate cells (HSCs) and reduced their toxicity to ordinary liver cells. VPSGCN units could trigger water splitting to generate O2 under 660 nm laser irradiation, improve the hypoxic environment of the fibrosis site, downregulate HIF-1α expression, and activate HSC ferroptosis via the HIF-1α/SLC7A11 pathway. In addition, generated O2 could also increase the reactive oxygen species (ROS) production of TSI units in a hypoxic environment, thereby completely reversing hypoxia-triggered PDT resistance to enhance the PDT effect. The combination of water-splitting materials and photodynamic materials showed a 1 + 1 > 2 effect in increasing oxygen levels in liver fibrosis, promoting ferroptosis of activated HSCs and reversing PDT resistance caused by hypoxia.

Metabolic reprogramming in liver fibrosis.

Chronic liver diseases, primarily metabolic dysfunction-associated steatotic liver disease (MASLD), harmful use of alcohol, or viral hepatitis, may result in liver fibrosis, cirrhosis, and cancer. Hepatic fibrogenesis is a complex process with interactions between different resident and non-resident heterogeneous liver cell populations, ultimately leading to deposition of extracellular matrix and organ failure. Shifts in cell phenotypes and functions involve pronounced transcriptional and protein synthesis changes that require metabolic adaptations in cellular substrate metabolism, including glucose and lipid metabolism, resembling changes associated with the Warburg effect in cancer cells. Cell activation and metabolic changes are regulated by metabolic stress responses, including the unfolded protein response, endoplasmic reticulum stress, autophagy, ferroptosis, and nuclear receptor signaling. These metabolic adaptations are crucial for inflammatory and fibrogenic activation of macrophages, lymphoid cells, and hepatic stellate cells. Modulation of these pathways, therefore, offers opportunities for novel therapeutic approaches to halt or even reverse liver fibrosis progression.

Beyond stiffness: Multiscale viscoelastic features as biomechanical markers for assessing cell types and states.

Cell mechanics are pivotal in regulating cellular activities, diseases progression, and cancer development. However, the understanding of how cellular viscoelastic properties vary in physiological and pathological stimuli remains scarce. Here, we develop a hybrid self-similar hierarchical theory-microrheology approach to accurately and efficiently characterize cellular viscoelasticity. Focusing on two key cell types associated with livers fibrosis-the capillarized liver sinusoidal endothelial cells and activated hepatic stellate cells-we uncover a universal two-stage power-law rheology characterized by two distinct exponents, αshort and αlong. The mechanical profiles derived from both exponents exhibit significant potential for discriminating among diverse cells. This finding suggests a potential common dynamic creep characteristic across biological systems, extending our earlier observations in soft tissues. Using a tailored hierarchical model for cellular mechanical structures, we discern significant variations in the viscoelastic properties and their distribution profiles across different cell types and states from the cytoplasm (elastic stiffness E1 and viscosity η), to a single cytoskeleton fiber (elastic stiffness E2), and then to the cell level (transverse expansion stiffness E3). Importantly, we construct a logistic-regression-based machine-learning model using the dynamic parameters that outperforms conventional cell-stiffness-based classifiers in assessing cell states, achieving an area under the curve of 97% vs. 78%. Our findings not only advance a robust framework for monitoring intricate cell dynamics but also highlight the crucial role of cellular viscoelasticity in discerning cell states across a spectrum of liver diseases and prognosis, offering new avenues for developing diagnostic and therapeutic strategies based on cellular viscoelasticity.

Inhibition of endogenous hydrogen sulfide production reduces activation of hepatic stellate cells via the induction of cellular senescence.

In chronic liver injury, quiescent hepatic stellate cells (HSCs) transdifferentiate into activated myofibroblast-like cells and produce large amounts of extracellular matrix components, e.g. collagen type 1. Cellular senescence is characterized by irreversible cell-cycle arrest, arrested cell proliferation and the acquisition of the senescence-associated secretory phenotype (SASP) and reversal of HSCs activation. Previous studies reported that H2S prevents induction of senescence via its antioxidant activity. We hypothesized that inhibition of endogenous H2S production induces cellular senescence and reduces activation of HSCs. Rat HSCs were isolated and culture-activated for 7 days. After activation, HSCs treated with H2S slow-releasing donor GYY4137 and/or DL-propargylglycine (DL-PAG), an inhibitor of the H2S-producing enzyme cystathionine γ-lyase (CTH), as well as the PI3K inhibitor LY294002. In our result, CTH expression was significantly increased in fully activated HSCs compared to quiescent HSCs and was also observed in activated stellate cells in a in vivo model of cirrhosis. Inhibition of CTH reduced proliferation and expression of fibrotic markers Col1a1 and Acta2 in HSCs. Concomitantly, DL-PAG increased the cell-cycle arrest markers Cdkn1a (p21), p53 and the SASP marker Il6. Additionally, the number of ß-galactosidase positive senescent HSCs was increased. GYY4137 partially restored the proliferation of senescent HSCs and attenuated the DL-PAG-induced senescent phenotype. Inhibition of PI3K partially reversed the senescence phenotype of HSCs induced by DL-PAG. Inhibition of endogenous H2S production reduces HSCs activation via induction of cellular senescence in a PI3K-Akt dependent manner. Our results show that cell-specific inhibition of H2S could be a novel target for anti-fibrotic therapy via induced cell senescence.

Agalactosyl IgG induces liver fibrogenesis via Fc gamma receptor 3a on human hepatic stellate cells.

The relevance of aberrant serum IgG N-glycosylation in liver fibrosis has been identified; however, its causal effect remains unclear. Because hepatic stellate cells (HSCs) contribute substantially to liver fibrosis, we investigated whether and through which mechanisms IgG N-glycosylation affects the fibrogenic properties of HSCs. Analysis of serum IgG1 N-glycome from 151 patients with chronic hepatitis B or liver cirrhosis revealed a positive correlation between Ishak fibrosis grading and IgG1 with agalactosyl N-glycoforms on the crystallizable fragment (Fc). Fc gamma receptor (FcγR) IIIa was observed in cultured human HSCs and HSCs in human liver tissues, and levels of FcγRIIIa in HSCs correlated with the severity of liver fibrosis. Additionally, agalactosyl IgG treatment caused HSCs to have a fibroblast-like morphology, enhanced migration and invasion capabilities, and enhanced expression of the FcγRIIIa downstream tyrosine-protein kinase SYK. Furthermore, agalactosyl IgG treatment increased fibrogenic factors in HSCs, including transforming growth factor (TGF)-ß1, total collagen, platelet-derived growth factor subunit B and its receptors, pro-collagen I-α1, α-smooth muscle actin, and matrix metalloproteinase 9. These effects were more pronounced in HSCs that stably expressed FCGR3A and were reduced in FCGR3A knockout cells. Agalactosyl IgG and TGF-ß1 each increased FCGR3A in HSCs. Furthermore, serum TGF-ß1 concentrations in patients were positively correlated with agalactosyl IgG1 levels and liver fibrosis severity, indicating a positive feedback loop involving agalactosyl IgG, HSC-FcγRIIIa, and TGF-ß1. In conclusion, agalactosyl IgG promotes fibrogenic characteristics in HSCs through FcγRIIIa. © 2024 The Pathological Society of Great Britain and Ireland.

KDM4C represses liver fibrosis by regulating H3K9me3 methylation of ALKBH5 and m6A methylation of snail1 mRNA.

OBJECTIVE: We aimed to disclose the molecular mechanism of snail1 in liver fibrosis. METHODS: Carbon tetrachloride (CCl4) was used to induce a liver fibrosis model in mice whereby serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were evaluated, and liver pathological alternations were assessed. Rat hepatic stellate cells (HSC-T6) were irritated with transforming growth factor (TGF)-ß1, followed by assessment of cell viability and migration. The levels of snail1, ALKBH5, and lysine specific demethylase 4C (KDM4C) were quantified by immunohistochemistry, western blot, or reverse transcription-quantitative polymerase chain reaction, in addition to α-smooth muscle actin (SMA), anti-collagen type I α1 (COL1A1), vimentin, and E-cadherin. Photoactivatable ribonucleoside-enhanced crosslinking and immunoprecipitation and RNA stability were evaluated to determine the relationship between ALKBH5 and snail1. Changes in KDM4C-bound ALKBH5 promoter and enrichment of histone H3 lysine 9 trimethylation (H3K9me3) at the ALKBH5 promoter were determined using chromatin immunoprecipitation. RESULTS: In fibrosis mice, snail1 was upregulated while ALKBH5 and KDM4C were downregulated. KDM4C overexpression reduced serum ALT and AST levels, liver injury, and α-SMA, COL1A1 and VIMENTIN expressions but increased E-cadherin expression. However, the aforementioned trends were reversed by concurrent overexpression of snail1. In HSC-T6 cells exposed to TGF-ß1, ALKBH5 overexpression weakened cell viability and migration, downregulated α-SMA, COL1A1 and VIMENTIN, upregulated E-CADHERIN, and decreased m6A modification of snail1 and its mRNA stability. KDM4C increased ALKBH5 expression by lowering H3K9me3 level, but inhibited HSC-T6 cell activation by regulating the ALKBH5/snail1 axis. CONCLUSION: KDM4C decreases H3K9me3 methylation to upregulate ALKBH5 and subsequently inhibits snail1, ultimately impeding liver fibrosis.

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.

SH-Alb inhibits phenotype remodeling of pro-fibrotic macrophage to attenuate liver fibrosis through SIRT3-SOD2 axis.

Albumin has a variety of biological functions, such as immunomodulatory and antioxidant activity, which depends largely on its thiol activity. However, in clinical trials, the treatment of albumin by injection of commercial human serum albumin (HSA) did not achieve the desired results. Here, we constructed reduced modified albumin (SH-Alb) for in vivo and in vitro experiments to investigate the reasons why HSA did not achieve the expected effects. SH-Alb was found to delay the progression of liver fibrosis in mice by alleviating liver inflammation and oxidative stress. Although R-Alb also has some of the above roles, the effect of SH-Alb is more remarkable. Mechanism studies have shown that SH-Alb reduces the release of pro-inflammatory and pro-fibrotic cytokine through the mitogen-activated protein kinase (MAPK) signaling pathway. In addition, SH-Alb deacetylates SOD2, a key enzyme of mitochondrial reactive oxygen species (ROS) production, by promoting the expression of SIRT3, thereby reducing the accumulation of ROS. Finally, macrophages altered by R-Alb or SH-Alb can inhibit the activation of hepatic stellate cells and endothelial cells, further delaying the progression of liver fibrosis. These results indicate that SH-Alb can remodel the phenotype of macrophages, thereby affecting the intrahepatic microenvironment and delaying the process of liver fibrosis. It provides a good foundation for the application of albumin in clinical treatment.

Naringin from Ganshuang granule inhibits inflammatory to relieve liver fibrosis through TGF-ß-Smad signaling pathway.

OBJECTIVE: The present study aims to investigate the specific protective effects and underlying mechanisms of Ganshuang granule (GSG) on dimethylnitrosamine (DMN)-induced hepatic fibrosis in rat models. METHODS: Hepatic fibrosis was experimentally evoked in rats by DMN administration, and varying dosages of GSG were employed as an intervention. Hepatocellular damage was assessed by measuring serum levels of aminotransferase and bilirubin, accompanied by histopathological examinations of hepatic tissue. The hepatic concentrations of platelet-derived growth factor (PDGF) and transforming growth factor-ß1 (TGF-ß1) were quantitated via enzyme-linked immunosorbent assay (ELISA). The expression of α-smooth muscle actin (α-SMA) within hepatic tissue was evaluated using immunohistochemical techniques. The levels of hepatic interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), and a spectrum of interleukins (IL-2, IL-4, IL-6, IL-10) were quantified by quantitative real-time PCR (qRT-PCR). Additionally, hepatic stellate cells (HSCs) were cultured in vitro and exposed to TNF-α in the presence of naringin, a principal component of GSG. The gene expression levels of tissue inhibitor of metalloproteinase-1 (TIMP-1) and matrix metallopeptidase-1 (MMP-1) in these cells were also quantified by qRT-PCR. Proliferative activity of HSCs was evaluated by the Cell Counting Kit-8 assay. Finally, alterations in Smad protein expression were analyzed through Western blotting. RESULTS: Administration of GSG in rats with fibrosis resulted in reduced levels of serum aminotransferases and bilirubin, along with alleviation of histopathological liver injury. Furthermore, the fibrosis rats treated with GSG exhibited significant downregulation of hepatic TGF-ß1, PDGF, and TNF-α levels. Additionally, GSG treatment led to increased mRNA levels of IFN-γ, IL-2, and IL-4, as well as decreased expression of α-SMA in the liver. Furthermore, treatment with naringin, a pivotal extract of GSG, resulted in elevated expression of MMP-1 and decreased levels of TIMP-1 in TNF-α-stimulated HSCs when compared to the control group. Additionally, naringin administration led to a reduction in Smad expression within the HSCs. CONCLUSION: GSG has the potential to mitigate fibrosis induced by DMN in rat models through the regulation of inflammatory and fibrosis factors. Notably, naringin, the primary extract of GSG, may exert a pivotal role in modulating the TGF-ß-Smad signaling pathway.

Advanced three-dimensional in vitro liver models to study the activity of anticancer drugs.

The liver is one of the most important organs in the human body. It performs many important functions, including being responsible for the metabolism of most drugs, which is often associated with its drug-induced damage. Currently, there are no ideal pharmacological models that would allow the evaluation of the effect of newly tested drugs on the liver in preclinical studies. Moreover, the influence of hepatic metabolism on the effectiveness of the tested drugs is rarely evaluated. Therefore, in this work we present an advanced model of the liver, which reflects most of the morphologically and metabolically important features of the liver in vivo, namely: three-dimensionality, cellular composition, presence of extracellular matrix, distribution of individual cell types in the structure of the liver model, high urea and albumin synthesis efficiency, high cytochrome p450 activity. In addition, the work, based on the example of commonly used anticancer drugs, shows how important it is to take into account hepatic metabolism in the effective assessment of their impact on the target organ, in this case cancer. In our research, we have shown that the most similar to liver in vivo are 3D cellular aggregates composed of three important liver cells, namely hepatocytes (HepG2), hepatic stellate cells (HSCs), and hepatic sinusoidal endothelial cells (HSECs). Moreover, we showed that the cells in 3D aggregate structure need time (cell-cell interactions) to improve proper liver characteristic. The triculture model additionally showed the greatest ability to metabolize selected anticancer drugs.

Nicotine aggravates liver fibrosis via α7 nicotinic acetylcholine receptor expressed on activated hepatic stellate cells in mice.

BACKGROUND: Smoking is a risk factor for liver cirrhosis; however, the underlying mechanisms remain largely unexplored. The α7 nicotinic acetylcholine receptor (α7nAChR) has recently been detected in nonimmune cells possessing immunoregulatory functions. We aimed to verify whether nicotine promotes liver fibrosis via α7nAChR. METHODS: We used osmotic pumps to administer nicotine and carbon tetrachloride to induce liver fibrosis in wild-type and α7nAChR-deficient mice. The severity of fibrosis was evaluated using Masson trichrome staining, hydroxyproline assays, and real-time PCR for profibrotic genes. Furthermore, we evaluated the cell proliferative capacity and COL1A1 mRNA expression in human HSCs line LX-2 and primary rat HSCs treated with nicotine and an α7nAChR antagonist, methyllycaconitine citrate. RESULTS: Nicotine exacerbated carbon tetrachloride-induced liver fibrosis in mice (+42.4% in hydroxyproline assay). This effect of nicotine was abolished in α7nAChR-deficient mice, indicating nicotine promotes liver fibrosis via α7nAChR. To confirm the direct involvement of α7nAChRs in liver fibrosis, we investigated the effects of genetic suppression of α7nAChR expression on carbon tetrachloride-induced liver fibrosis without nicotine treatment. Profibrotic gene expression at 1.5 weeks was significantly suppressed in α7nAChR-deficient mice (-83.8% in Acta2, -80.6% in Col1a1, -66.8% in Tgfb1), and collagen content was decreased at 4 weeks (-22.3% in hydroxyproline assay). The in vitro analysis showed α7nAChR expression in activated but not in quiescent HSCs. Treatment of LX-2 cells with nicotine increased COL1A1 expression (+116%) and cell proliferation (+10.9%). These effects were attenuated by methyllycaconitine citrate, indicating the profibrotic effects of nicotine via α7nAChR. CONCLUSIONS: Nicotine aggravates liver fibrosis induced by other factors by activating α7nAChR on HSCs, thereby increasing their collagen-producing capacity. We suggest the profibrotic effect of nicotine is mediated through α7nAChRs.

BTLA deficiency promotes HSC activation and protects against hepatic ischemia-reperfusion injury.

BACKGROUND AND AIMS: Hepatic ischemia-reperfusion injury (IRI) is unavoidable even despite the development of more effective surgical approaches. During hepatic IRI, activated HSC (aHSC) are involved in liver injury and recovery. APPROACH AND RESULT: A proportion of aHSC increased significantly both in the mouse liver tissues with IRI and in the primary mouse HSCs and LX-2 cells during hypoxia-reoxygenation. "Loss-of-function" experiments revealed that depleting aHSC with gliotoxin exacerbated liver damage in IRI mice. Subsequently, we found that the transcription of mRNA and the expression of B and T lymphocyte attenuator (BTLA) protein were lower in aHSC compared with quiescent HSCs. Interestingly, overexpression or knockdown of BTLA resulted in opposite changes in the activation of specific markers for HSCs such as collagen type I alpha 1, α-smooth muscle actin, and Vimentin. Moreover, the upregulation of these markers was also observed in the liver tissues of global BLTA-deficient (BTLA-/-) mice and was higher after hepatic IRI. Compared with wild-type mice, aHSC were higher, and liver injury was lower in BTLA-/- mice following IRI. However, the depletion of aHSC reversed these effects. In addition, the depletion of aHSC significantly exacerbated liver damage in BTLA-/- mice with hepatic IRI. Furthermore, the TGF-ß1 signaling pathway was identified as a potential mechanism for BTLA to negatively regulate the activation of HSCs in vivo and in vitro. CONCLUSIONS: These novel findings revealed a critical role of BTLA. Particularly, the receptor inhibits HSC-activated signaling in acute IRI, implying that it is a potential immunotherapeutic target for decreasing the IRI risk.