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

Hypoxia-inducible factor-1 alpha (HIF-1α) inhibitor AMSP-30 m attenuates CCl4-induced liver fibrosis in mice by inhibiting the sonic hedgehog pathway

Liver fibrosis is a passive and irreversible wound healing process caused by chronic liver injury. Research has shown that the upregulation of hypoxia inducible factor-1 alpha (HIF-1α) is closely related to the occurrence and development of liver fibrosis and HIF-1 α may be a promising target for the treatment of liver fibrosis. AMSP-30 m is a newly developed novel HIF-1α inhibitor by our group, which has strong anti-tumor and anti-inflammatory effects. In this study, we described the therapeutic effect and specific mechanism of AMSP-30 m on carbon tetrachloride (CCl4) induced liver fibrosis in mice. Liver fibrosis induced by CCl4 in mice and liver fibrosis induced by cobalt dichloride (CoCl2) in LX-2 cells (human hepatic stellate cell (HSC) line) were studied. Hematoxylin & eosin (H&E)and Masson's trichrome staining were used to observe pathological conditions. Western Blot, immunofluorescence and immunohistochemistry were used to detect protein expression and localization in cells, and quantitative real-time PCR analysis (qRT-PCR) was used to detect mRNA expression. Biochemical detection kits were used to detect alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. The results demonstrated that AMSP-30 m significantly alleviated pathological symptoms, reduced ALT and AST levels, and inhibited the expression of alpha-smooth muscle actin (α-SMA) and collagen type I (COL1α1) in CCl4-induced liver fibrosis in mice. AMSP-30 m could significantly reduce the expression of HIF-1α and sonic hedgehog (Shh) pathway related proteins (Smoothened (Smo), Shh, and glioma-associated oncogene-1 (Gli-1)) in CCl4 induced liver fibrosis mice. AMSP-30 m also played a similar role in the CoCl2-induced anoxic liver fibrosis model of LX-2 cells. Further experiments showed that Cyclopamine (a Shh inhibitor) could significantly inhibit the increase of α-SMA and COL1α1 resulting from HIF-1α but not significantly inhibit HIF-1α induced by CoCl2 in LX-2 cells. And the combination of Cyclopamine and AMSP-30 m further reduced the expression of α-SMA and COL1α1 induced by HIF-1α. In summary, this study demonstrates that the HIF-1α inhibitor AMSP-30 m exerts a robust anti-fibrotic effect by inhibiting the Shh pathway, which is identified as a critical underlying mechanism. These findings suggest a promising therapeutic strategy for the treatment of liver fibrosis.

Type I IFN receptor blockade alleviates liver fibrosis through macrophage-derived STAT3 signaling

Liver macrophages play a role in the development of liver fibrosis progression via the regulation of inflammatory signaling. However, the precise mechanisms of macrophages contributing to liver fibrosis progression remain unclear. Using a preclinical model of CCl4-treated mice, we determined the composition of immune cells and the alteration of inflammatory gene expression. Our findings revealed a significant increase in liver macrophages, particularly those derived from infiltrating blood monocytes, in fibrotic mice. Moreover, the expression levels of type I IFN signature genes such as IFNα, IFNβ, ISG15, USP18, Ifi44, Ifit1, Ifit2, IRF3, and IRF7 were elevated in fibrotic mice. To determine the role of type I IFN signaling in liver fibrosis, we administered an IFNAR-1 antibody to block this pathway for 3 days prior to harvesting the liver. Notably, IFNAR-1 blockade reduced macrophage numbers compared to control mice and alleviated liver fibrosis in mice with increased hepatocyte proliferation and apoptosis. The ratio of P-STAT3/P-STAT1 in monocyte-derived macrophages was increased in the IFNAR-1 blockade group compared to fibrotic mice, and this was related to the appearance of M2 macrophage differentiation. Additionally, single-cell RNA-seq analysis indicated that IFNAR blockade affected inflammatory pathways involved in hepatocyte regeneration and fibrosis prevention. Taken together, IFNAR-1 blockade alleviates liver fibrosis progression by modulating macrophage inflammatory responses. These results provide insights for developing anti-fibrotic therapies against type I IFN signaling.

Comparative study on the anti-alcoholic liver disease efficiency of the ethanol- and water-soluble polysaccharides from Baijiu vinasses

Ethanol- and water-soluble polysaccharides were extracted from Baijiu vinasses (EP and WP), respectively. EP was dominantly composed by arabinose, glucose and xylose with molar ratio of 8.81: 76.82: 6.9. While, WP was dominantly composed by galactose, glucose and mannose with molar ratio of 8.32: 56.05: 25.19. The molecular weights and reducing sugar contents in EP and WP were 6.2 kDa vs. 16.1 kDa and 24.52 ± 0.97 % vs. 19.77 ± 0.75 %, respectively. Alterations in activation of the Nrf2/HO-1 signalling pathway and increases in the abundance of Lachnospiraceae and Akkermansia and their associated metabolisms could be the general mechanism by which Baijiu vinasses (BV) polysaccharides alleviated alcohol-induced liver disease (ALD) in mice. Due to the different physicochemical characteristics, the ALD alleviation efficiency was different. EP exhibited higher efficiency in oxidative stress suppressing and lipid alternation by activating the peroxisome proliferators-activated receptors (PPAR) signalling pathway. WP exhibited higher efficiency in liver damage repairing with the controlment in tryptophan metabolism pathway. This study exhibited the potential biofunction of BV polysaccharides in ALD alleviation and could promote the BV upcycling.

The CYP4/20-HETE/GPR75 axis in the progression metabolic dysfunction-associated steatosis liver disease (MASLD) to chronic liver disease

Introduction

Metabolic-dysfunction-associated steatosis liver disease (MASLD) is a progressive liver disease from simple steatosis, steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. Chronic liver diseases (CLDs) can lead to portal hypertension, which is a major cause of complications of cirrhosis. CLDs cause structural alterations across the liver through increased contents of extracellular matrix (ECM), driving dysfunction of liver sinusoidal endothelial cells (LSECs) alongside hepatic stellate cells (HSCs) and activated resident or infiltrating immune cells. Bioactive arachidonic metabolites have diverse roles in the progression of MASLD. Both secreted levels of 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acid (EET) are elevated in patients with liver cirrhosis.

Methods

CLD samples were evaluated for changes in free fatty acids (FFA), cholesterol, bilirubin, bile acid, reactive oxygen species (ROD), lipid peroxidation, myeloperoxidase activity and hydroxyproline levels to evaluate the degrees of liver damage and fibrosis. To address the role of the CYP4/20-HETE/GPR75 axis, we measured the amount and the synthesis of 20-HETE in patients with CLD, specifically during the progression of MASLD. Additionally, we evaluated gene expression and protein levels of GPR75, a high-affinity receptor for 20-HETE across CLD patient samples.

Results

We observed an increase in 20-HETE levels and synthesis during the progression of MASLD. Increased synthesis of 20-HETE correlated with the expression of CYP4A11 genes but not CYP4F2. These results were confirmed by increased P4504A11 protein levels and decreased P4504F2 protein levels during the development and progression of MASLD. The gene expression and protein levels of GPR75, the major receptor for 20-HETE, increased in the progression of MASLD. Interestingly, the CYP4A11 and GPR75 mRNA levels increased in steatohepatitis but dramatically dropped in cirrhosis and then increased in patients with HCC. Also, protein levels of P4504A11 and GPR75 mirrored their mRNA levels.

Discussion

These results indicate that the CYP4A11 and subsequent GPR75 genes are coordinately regulated in the progression of MASLD and may have multiple roles, including 20-HETE activation of peroxisome proliferator-activated receptor α (PPARα) in steatosis and GPR75 in CLD through either increased cell proliferation or vasoconstriction in portal hypertension during cirrhosis. The abrupt reduction in CYP4A11 and GPR75 in patients with cirrhosis may also be due to increased 20-HETE, serving as a feedback mechanism via GPR75, leading to reduced CYP4A11 and GPR75 gene expression. This work illustrates key correlations associated with the CYP4/20-HETE/GPR75 axis and the progression of liver disease in humans.

Ginsenoside, a potential natural product against liver diseases: a comprehensive review from molecular mechanisms to application

Liver disease constitutes a significant cause of global mortality, with its pathogenesis being multifaceted. Identifying effective pharmacological and preventive strategies is imperative for liver protection. Ginsenosides, the major bioactive compounds found in ginseng, exhibit multiple pharmacological activities including protection against liver-related diseases by mitigating liver fat accumulation and inflammation, preventing hepatic fibrosis, and exerting anti-hepatocarcinogenic effects. However, a comprehensive overview elucidating the regulatory pathways associated with ginsenosides in liver disease remains elusive. This review aims to consolidate the molecular mechanisms through which different ginsenosides ameliorate distinct liver diseases, alongside the pathogenic factors underlying liver ailments. Notably, ginsenosides Rb1 and Rg1 demonstrate significantly effective in treating fatty liver, hepatitis, and liver fibrosis, and ginsenosides CK and Rh2 exhibit potent anti-hepatocellular carcinogenic effects. Their molecular mechanisms underlying these effects primarily involve the modulation of AMPK, NF-κB, TGF-β, NFR2, JNK, and other pathways, thereby attenuating hepatic fat accumulation, inflammation, inhibition of hepatic stellate cell activation, and promoting apoptosis in hepatocellular carcinoma cells. Furthermore, it provides insights into the safety profile and current applications of ginsenosides, thereby facilitating their clinical development. Consequently, ginsenosides present promising prospects for liver disease management, underscoring their potential as valuable therapeutic agents in this context.

The effect of saraglitazar on TGF-β-induced smad3 phosphorylation and expression of genes related to liver fibrosis in LX2 cell line

BACKGROUND AND PURPOSE

Liver fibrosis is a reversible liver injury that occurs as a result of many chronic inflammatory diseases and can lead to cirrhosis, which is irreversible and fatal. So, we studied the anti-fibrotic effects of saroglitazar on LX-2 cell lines, as a dual PPARα/γ agonist.

METHODS

Cells, after 80% confluence, were treated with TGF-β (2 ng/mL) for 24 h. Then cells were treated with saroglitazar at different doses (2.5, 5, 10 µM) for 24 h. After same incubation, the cells of control group, TGF-β group, and TGF-β + saroglitazar group were harvested for RNA and protein extraction to determine the effects of saroglitazar. RT-PCR and western blot methods were used to express genes related to fibrosis.

RESULTS

Our results show that the relative expression of α-SMA, collagen1α, N-cadherin, NOX (1, 2, and 4), and phosphorylated Smad3 protein was significantly higher in TGF-β-treated cells compared with the normal group, and E-cadherin expression was decreased in TGF-β-treated cells. After TGF-β-treated cells were exposed to saroglitazar, the expression of these genes was significantly reversed (P < 0.05).

CONCLUSIONS

Our results clearly show the short-term inhibitory role of saroglitazar in the expression of fibrotic factors using the TGF-β/Smad signaling pathway. These results suggest that saroglitazar can be considered as a suitable therapeutic strategy for fibrotic patients. Although more studies are needed.

Bioactive signalling lipids as drivers of chronic liver diseases

Lipids are important in multiple cellular functions, with most having structural or energy storage roles. However, a small fraction of lipids exert bioactive roles through binding to G protein-coupled receptors and induce a plethora of processes including cell proliferation, differentiation, growth, migration, apoptosis, senescence and survival. Bioactive signalling lipids are potent modulators of metabolism and energy homeostasis, inflammation, tissue repair and malignant transformation. All these events are involved in the initiation and progression of chronic liver diseases. In this review, we focus specifically on the roles of bioactive lipids derived from phospholipids (lyso-phospholipids) and poly-unsaturated fatty acids (eicosanoids, pro-resolving lipid mediators and endocannabinoids) in prevalent chronic liver diseases (alcohol-associated liver disease, non-alcoholic fatty liver disease, viral hepatitis and hepatocellular carcinoma). We discuss the balance between pathogenic and beneficial bioactive lipids as well as potential therapeutic targets related to the agonism or antagonism of their receptors.

Alleviation of D-gal-induced senile liver injury by Rg3, a signature component of red ginseng

To investigate the mechanism by which ginsenoside Rg3 regulates oxidative stress (OS) and inflammation through NF/KB pathway to delay mouse liver injury. This work randomized Balbc mice as four groups: Normal, D-gal, Rg3-L, Rg3-H. Paraffin-embedded liver tissue sections were prepared, later, BAX/BCL-2 protein expression was observed by HE, Sirius red, TUNEL and immunofluorescence to detect apoptotic injury and α-SMA/TGF-β protein expression to detect fibrosis, and liver inflammation-related protein NF-KB was detected. HE and TUNEL staining showed that Rg3 reduced necrotic cells and fibrosis in liver-injured mice, Rg3 increased anti-inflammatory cytokine IL-18 and reduced TNF-α, IL-1β and IL-6 expression. Conclusion: Ginsenoside Rg3 can effectively antagonize D-gal's role in mouse liver injury, and its mechanism may be associated with regulating inflammatory pathway by Rg.

Eicosanoids and other oxylipins in liver injury, inflammation and liver cancer development

Liver cancer is a malignancy developed from underlying liver disease that encompasses liver injury and metabolic disorders. The progression from these underlying liver disease to cancer is accompanied by chronic inflammatory conditions in which liver macrophages play important roles in orchestrating the inflammatory response. During this process, bioactive lipids produced by hepatocytes and macrophages mediate the inflammatory responses by acting as pro-inflammatory factors, as well as, playing roles in the resolution of inflammation conditions. Here, we review the literature discussing the roles of bioactive lipids in acute and chronic hepatic inflammation and progression to cancer.