Hepatic Stellate Cell-Macrophage Crosstalk in Liver Fibrosis and Carcinogenesis

Reducing Nogo-B Improves Hepatic Fibrosis by Inhibiting BACe1-Mediated Autophagy

BACKGROUND

Hepatic fibrosis (HF) is a histopathological change in the process of long-term liver injury caused by cytokine secretion and internal environment disturbance, resulting in excessive liver repair and fiber scar. Nogo-B protein is widely distributed in peripheral tissues and organs and can regulate the migration of endothelial cells by activating TGF-β1 in vascular remodeling after injury. Nogo-B has been shown to promote organ fibrosis. This study was to determine the role of Nogo-B in HF.

METHODS

An HF model was built by intraperitoneal injections with 20% carbon tetrachloride. Localization of Nogo-B was detected by FISH. The interaction between Nogo-B and BACE1 was confirmed by Co-IP. Autophagy flux was analyzed using tandem mRFP-GFP-LC3 fluorescence microscopy, electron microscopy, and western blotting. Detection of serum AST and ALT and H&E staining were utilized to detect the degree of liver injury. The HF was evaluated by Masson trichromatic staining. RT-qPCR, western blotting, and immunofluorescence were employed to detect relevant indicators.

RESULTS

Reducing Nogo-B suppressed AST and ALT levels, the accumulation of collagen I and α-SMA, and expressions of pro-fibrotic genes in mouse liver. BACE1 was a potential downstream target of Nogo-B. Nogo-B was upregulated in TGF-β1-activated hepatic stellate cells (HSCs). Knocking down Nogo-B caused the downregulation of pro-fibrotic genes and inhibited viability of HSCs. Nogo-B knockdown prevented CCL4-induced fibrosis, accompanied by downregulation of extracellular matrix. Nogo-B inhibited HSC autophagy and increased lipid accumulation. BACE1 knockdown inhibited HSC autophagy and activation in LX-2 cells.

CONCLUSION

Nogo-B knockdown prevents HF by directly inhibiting BACe1-mediated autophagy.

Unveiling the role of the Hedgehog signaling pathway in chronic liver disease: Therapeutic insights and strategies

The Hedgehog (Hh) signaling plays a crucial role in adult liver repair by promoting the expansion and differentiation of hepatic progenitor cells into mature hepatocytes and cholangiocytes. Elevated Hh signaling is associated with severe chronic liver diseases, making Hh inhibitors a promising therapeutic option. Sonidegib and vismodegib, both FDA-approved Smoothened (Smo) inhibitors for basal cell carcinoma (BCC), have shown potential for application in chronic liver disorders based on clinical evidence. We highlight the vital role of the Hh pathway in metabolic dysfunction-associated steatotic liver disease (MASLD)/metabolic dysfunction-associated steatohepatitis (MASH), liver fibrosis, and hepatocellular carcinoma (HCC). Moreover, therapeutic strategies targeting the Hh pathway in chronic liver diseases have been discussed, providing a basis for improving disease management and outcomes.

Cenicriviroc Suppresses and Reverses Steatohepatitis by Regulating Macrophage Infiltration and M2 Polarization in Mice

The inhibition of hepatic macrophage and Kupfer cell recruitment and activation is a potential strategy for treating insulin resistance and nonalcoholic steatohepatitis (NASH). Cenicriviroc (CVC), a dual C-C chemokine receptor 2 (CCR2) and CCR5 antagonist, has shown antifibrotic activity in murine models of NASH and has been evaluated in clinical trials on patients with NASH. This study investigated the effects of CVC on macrophage infiltration and polarization in a lipotoxic model of NASH. C57BL/6 mice were fed a high-cholesterol, high-fat (CL) diet or a CL diet containing 0.015% CVC (CL + CVC) for 12 weeks. Macrophage recruitment and activation were assayed by immunohistochemistry and flow cytometry. CVC supplementation attenuated excessive hepatic lipid accumulation and peroxidation and alleviated glucose intolerance and hyperinsulinemia in the mice that were fed the CL diet. Flow cytometry analysis revealed that compared with the CL group, mice fed the CL + CVC diet had fewer M1-like macrophages, more M2-like macrophages, and fewer T cell counts, indicating that CVC caused an M2-dominant shift of macrophages in the liver. Similarly, CVC decreased lipopolysaccharide-stimulated M1-like macrophage activation, whereas it increased interleukin-4-induced M2-type macrophage polarization in vitro. In addition, CVC attenuated hepatic fibrosis by repressing hepatic stellate cell activation. Lastly, CVC reversed insulin resistance as well as steatosis, inflammation, and fibrosis of the liver in mice with pre-existing NASH. In conclusion, CVC prevented and reversed hepatic steatosis, insulin resistance, inflammation, and fibrogenesis in the liver of NASH mice via M2 macrophage polarization.

Τ cell-mediated adaptive immunity in the transition from metabolic dysfunction-associated steatohepatitis to hepatocellular carcinoma

Metabolic dysfunction-associated steatohepatitis (MASH) is the progressed version of metabolic dysfunction-associated steatotic liver disease (MASLD) characterized by inflammation and fibrosis, but also a pathophysiological "hub" that favors the emergence of liver malignancies. Current research efforts aim to identify risk factors, discover disease biomarkers, and aid patient stratification in the context of MASH-induced hepatocellular carcinoma (HCC), the most prevalent cancer among MASLD patients. To investigate the tumorigenic transition in MASH-induced HCC, researchers predominantly exploit preclinical animal-based MASH models and studies based on archived human biopsies and clinical trials. Recapitulating the immune response during tumor development and progression is vital to obtain mechanistic insights into MASH-induced HCC. Notably, the advanced complexity behind MASLD and MASH pathogenesis shifted the research focus towards innate immunity, a fundamental element of the hepatic immune niche that is usually altered robustly in the course of liver disease. During the last few years, however, there has been an increasing interest for deciphering the role of adaptive immunity in MASH-induced HCC, particularly regarding the functions of the various T cell populations. To effectively understand the specific role of T cells in MASH-induced HCC development, scientists should urgently fill the current knowledge gaps in this field. Pinpointing the metabolic signature, sketching the immune landscape, and characterizing the cellular interactions and dynamics of the specific T cells within the MASH-HCC liver are essential to unravel the mechanisms that adaptive immunity exploits to enable the emergence and progression of this cancer. To this end, our review aims to summarize the current state of research regarding the T cell functions linked to MASH-induced HCC.

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

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

Wuling capsule modulates macrophage polarization by inhibiting the TLR4-NF-κB signaling pathway to relieve liver fibrosis

BACKGROUND AND PURPOSE

Wuling capsule (WL) has good efficacy in the clinical treatment of chronic hepatitis B and liver injury. Liver fibrosis is a common pathological feature of chronic liver disease and may progress to irreversible cirrhosis and liver cancer. Accumulating evidence reveals that modulating macrophage polarization contribute to the therapy of liver fibrosis. However, the effects of WL on modulating macrophage polarization to relive liver fibrosis remain unclear. This study investigated the anti-liver fibrosis effects of WL in carbon tetrachloride (CCl4)-induced liver fibrosis in rats, and the modulation effects and underlying molecular mechanism on macrophage polarization.

METHODS

A rat liver fibrosis model was constructed by intraperitoneal injection of 40 % CCl4 olive oil mixture. At 2, 4, 6, and 8 weeks, the histopathological status of the liver was assessed by hematoxylin-eosin (HE) and Masson staining; the liver biochemical indexes were measured in rat liver tissue. The expression levels of inflammatory cytokines in liver tissue were detected by ELISA. The mRNA levels and proteins expression of macrophage markers of different phenotypes, TLR4-NF-κB signaling pathway indicators were detected independently by ELISA, immunofluorescence, RT-PCR and western blotting.

RESULTS

In vivo, WL treatment attenuated abnormal changes in weight, organ indices and biochemical indices, alleviated pathological changes, and reduced collagen fiber deposition as well as the expression of α-SMA in liver tissues. Further studies revealed that WL decreased the expression of the macrophage M1 polarization markers inducible nitric oxide synthase (iNOS), TNF-α, IL-6, and CD86, promoted the expression of the M2 macrophage polarization markers IL-10, CD206, and arginase-1 (Arg-1), and inhibited the activation of the TLR4-NF-κB signaling pathway via several key signaling proteins. In vitro, WL significantly suppressed macrophage M1 polarization, and promoted M2 polarization while boosted M1 polarization transform to M2 polarization in LPS-activated RAW264.7 cells.

CONCLUSIONS

This study demonstrated that WL modulated macrophage polarization against liver fibrosis mainly by inhibiting the activation of the TLR4-NF-κB signaling pathway.

Tianhuang formula ameliorates liver fibrosis by inhibiting CCL2-CCR2 axis and MAPK/NF-κB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

In the progression of chronic liver diseases, liver fibrosis is a reversible pathophysiologic event for liver diseases prognosis and risk of cirrhosis. Liver injury factors of different etiologies mediate this process. There is still a lack of effective medications for treating liver fibrosis. Additionally, the ameliorative effects of traditional herbs on liver fibrosis have been commonly reported. Tianhuang formula (THF) is a drug combination consisting of 2 traditional Chinese herbs, which has been showing significant improvement in metabolic liver diseases. However, the hepatoprotective effect and mechanism of THF in ameliorating liver fibrosis are still unclear.

AIM OF THE STUDY

This study aimed to investigate the effects of THF on carbon tetrachloride (CCl4)-induced and methionine-choline-deficient (MCD) diet-induced liver fibrosis model and to reveal the potential mechanisms. It can provide experimental evidence for THF as a therapeutic candidate for liver fibrosis.

MATERIALS AND METHODS

In this study, CCl4-induced mice were treated with THF (80 mg/kg, 160 mg/kg) or Fuzheng Huayu (FZHY) capsules (4.8 g/kg) for 6 weeks. MCD-induced mice received the same doses of THF or FZHY for 4 weeks. FZHY is used as a comparative study in these two models. Following that, using kit reagents detected changes in relevant serum and liver biochemical indicators. Histological changes in mouse liver were measured by staining of H&E and Sirius Red. The markers expression of liver fibrosis and inflammation were detected using qRT-PCR, western blotting and immunohistochemical staining analysis. The potential regulatory mechanism of THF to ameliorate liver fibrosis was performed by RNA-sequencing analysis. Finally, the analysis results were verified by immunofluorescence co-staining, qRT-PCR and western blotting.

RESULTS

Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and hepatic triglyceride (TG) levels in CCl4 and MCD-induced liver fibrosis mice were significantly improved after THF treatment. Meanwhile, the expression of fibrosis and inflammation markers were significantly suppressed. Furthermore, THF downregulated the expression of the macrophage marker CD68. According to RNA-sequencing analysis, we found the CCL2-CCR2 axis and MAPK/NF-κB as the potential signaling pathway for THF against liver fibrosis.

CONCLUSION

This study revealed that THF ameliorated liver injury, inflammation and fibrotic process by inhibiting CCL2-CCR2 axis and its downstream MAPK/NF-κB signaling pathway.

Abnormal metabolism in hepatic stellate cells: Pandora's box of MAFLD related hepatocellular carcinoma

Metabolic associated fatty liver disease (MAFLD) is a significant risk factor for the development of hepatocellular carcinoma (HCC). Hepatic stellate cells (HSCs), as key mediators in liver injury response, are believed to play a crucial role in the repair process of liver injury. However, in MAFLD patients, the normal metabolic and immunoregulatory mechanisms of HSCs become disrupted, leading to disturbances in the local microenvironment. Abnormally activated HSCs are heavily involved in the initiation and progression of HCC. The metabolic disorders and abnormal activation of HSCs not only initiate liver fibrosis but also contribute to carcinogenesis. In this review, we provide an overview of recent research progress on the relationship between the abnormal metabolism of HSCs and the local immune system in the liver, elucidating the mechanisms of immune imbalance caused by abnormally activated HSCs in MAFLD patients. Based on this understanding, we discuss the potential and challenges of metabolic-based and immunology-based mechanisms in the treatment of MAFLD-related HCC, with a specific focus on the role of HSCs in HCC progression and their potential as targets for anti-cancer therapy. This review aims to enhance researchers' understanding of the importance of HSCs in maintaining normal liver function and highlights the significance of HSCs in the progression of MAFLD-related HCC.

Chemokine receptor CCR1 regulates macrophage activation through mTORC1 signaling in nonalcoholic steatohepatitis

BACKGROUND AND AIMS

Chemokine (CC motif) receptor 1 (CCR1) promotes liver fibrosis in mice. However, its effects on nonalcoholic steatohepatitis (NASH) remain unclear. Therefore, the present study aimed to investigate the role of CCR1 in the progression of NASH.

METHODS

Human serum and liver tissues were obtained from patients with NASH and controls. Systemic (Ccr1-/-) and liver macrophage-knockout Ccr1 (Ccr1LKD) mice were fed a high-cholesterol and high-fat (CL) diet for 12 weeks or a methionine/choline-deficient (MCD) diet for 4 weeks. BX471 was used to pharmacologically inhibit CCR1 in CL-fed mice.

RESULTS

CCR1 was significantly upregulated in liver samples from patients with NASH and in animal models of dietary-induced NASH. In the livers of mice fed a CL diet for 12 weeks, the CCR1 protein colocalized with F4/80+ macrophages rather than with hepatic stellate cells. Compared to their wild-type littermates, Ccr1-/- mice fed with the CL or MCD diet showed inhibition of NASH-associated hepatic steatosis, inflammation, and fibrosis. Mechanistically, Ccr1 deficiency suppressed macrophage infiltration and activation by attenuating the mechanistic target of rapamycin complex 1 (mTORC1) signaling. Similar results were observed in Ccr1LKD mice administered the CL diet. Moreover, CCR1 inhibition by BX471 effectively suppressed NASH progression in CL-fed mice.

CONCLUSIONS

Ccr1 deficiency mitigated macrophage activity by inhibiting mTORC1 signaling, thereby preventing the development of NASH. Notably, the CCR1 inhibitor BX471 protected against NASH. These findings would help in developing novel strategies for the treatment of NASH.

Investigating the Role of Non-Coding RNA in Non-Alcoholic Fatty Liver Disease

Non-coding RNAs (ncRNAs) are RNA molecules that do not code for protein but play key roles in regulating cellular processes. NcRNAs globally affect gene expression in diverse physiological and pathological contexts. Functionally important ncRNAs act in chromatin modifications, in mRNA stabilization and translation, and in regulation of various signaling pathways. Non-alcoholic fatty liver disease (NAFLD) is a set of conditions caused by the accumulation of triacylglycerol in the liver. Studies of ncRNA in NAFLD are limited but have demonstrated that ncRNAs play a critical role in the pathogenesis of NAFLD. In this review, we summarize NAFLD's pathogenesis and clinical features, discuss current treatment options, and review the involvement of ncRNAs as regulatory molecules in NAFLD and its progression to non-alcoholic steatohepatitis (NASH). In addition, we highlight signaling pathways dysregulated in NAFLD and review their crosstalk with ncRNAs. Having a thorough understanding of the disease process's molecular mechanisms will facilitate development of highly effective diagnostic and therapeutic treatments. Such insights can also inform preventive strategies to minimize the disease's future development.

The roles of epigallocatechin gallate in the tumor microenvironment, metabolic reprogramming, and immunotherapy

Cancer, a disease that modern medicine has not fully understood and conquered, with its high incidence and mortality, deprives countless patients of health and even life. According to global cancer statistics, there were an estimated 19.3 million new cancer cases and nearly 10 million cancer deaths in 2020, with the age-standardized incidence and mortality rates of 201.0 and 100.7 per 100,000, respectively. Although remarkable advancements have been made in therapeutic strategies recently, the overall prognosis of cancer patients remains not optimistic. Consequently, there are still many severe challenges to be faced and difficult problems to be solved in cancer therapy today. Epigallocatechin gallate (EGCG), a natural polyphenol extracted from tea leaves, has received much attention for its antitumor effects. Accumulating investigations have confirmed that EGCG can inhibit tumorigenesis and progression by triggering apoptosis, suppressing proliferation, invasion, and migration, altering tumor epigenetic modification, and overcoming chemotherapy resistance. Nevertheless, its regulatory roles and biomolecular mechanisms in the immune microenvironment, metabolic microenvironment, and immunotherapy remain obscure. In this article, we summarized the most recent updates about the effects of EGCG on tumor microenvironment (TME), metabolic reprogramming, and anti-cancer immunotherapy. The results demonstrated EGCG can promote the anti-cancer immune response of cytotoxic lymphocytes and dendritic cells (DCs), attenuate the immunosuppression of myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs), and inhibit the tumor-promoting functions of tumor-associated macrophages (TAMs), tumor-associated neutrophils (TANs), and various stromal cells including cancer-associated fibroblasts (CAFs), endothelial cells (ECs), stellate cells, and mesenchymal stem/stromal cells (MSCs). Additionally, EGCG can suppress multiple metabolic reprogramming pathways, including glucose uptake, aerobic glycolysis, glutamine metabolism, fatty acid anabolism, and nucleotide synthesis. Finally, EGCG, as an immunomodulator and immune checkpoint blockade, can enhance immunotherapeutic efficacy and may be a promising candidate for antitumor immunotherapy. In conclusion, EGCG plays versatile regulatory roles in TME and metabolic reprogramming, which provides novel insights and combined therapeutic strategies for cancer immunotherapy.

Crosstalk between fibroblasts and immunocytes in fibrosis: From molecular mechanisms to clinical trials

BACKGROUND

The impact of fibroblasts on the immune system provides insight into the function of fibroblasts. In various tissue microenvironments, multiple fibroblast subtypes interact with immunocytes by secreting growth factors, cytokines, and chemokines, leading to wound healing, fibrosis, and escape of cancer immune surveillance. However, the specific mechanisms involved in the fibroblast-immunocyte interaction network have not yet been fully elucidated.

MAIN BODY AND CONCLUSION

Therefore, we systematically reviewed the molecular mechanisms of fibroblast-immunocyte interactions in fibrosis, from the history of cellular evolution and cell subtype divisions to the regulatory networks between fibroblasts and immunocytes. We also discuss how these communications function in different tissue and organ statuses, as well as potential therapies targeting the reciprocal fibroblast-immunocyte interplay in fibrosis. A comprehensive understanding of these functional cells under pathophysiological conditions and the mechanisms by which they communicate may lead to the development of effective and specific therapies targeting fibrosis.

Interleukin-34 is more suitable than macrophage colony-stimulating factor for predicting liver significant fibrosis in patients with chronic hepatitis B

AIMS

Interleukin-34 (IL-34) and macrophage colony-stimulating factor (CSF-1) have similar functions, such as promoting the formation of liver fibrosis. This study aimed to evaluate and compare the diagnostic value of serum IL-34 and CSF-1 for significant liver fibrosis in patients with chronic hepatitis B (CHB).

METHODS

A total of 369 CHB patients, consisting of 208 HBeAg-negative patients and 161 HBeAg-positive patients, were enrolled in this study. Additionally, 72 healthy individuals served as healthy controls (HCs). Serum levels of IL-34 and CSF-1 were measured using the enzyme-linked immunosorbent assay method. Liver fibrosis grades were assessed using the modified Scheuer scoring system.

RESULTS

Serum IL-34 and CSF-1 levels exhibited significant elevation in both HBeAg-negative and HBeAg-positive patients in comparison to HCs (p < 0.001). IL-34 emerged as an independent factor linked to significant liver fibrosis, whereas CSF-1 did not exhibit such an association. Receiver operating characteristic (ROC) analysis indicated higher areas under the curves (AUCs) for IL-34 (0.814, p < 0.001 and 0.673, p < 0.001) when diagnosing significant liver fibrosis in HBeAg-negative and HBeAg-positive patients, respectively, as opposed to CSF-1 (0.602, p < 0.001; 0.619, p = 0.385). Within the HBeAg-negative patient subgroup, the AUC for IL-34 surpassed that of FIB-4 (p = 0.009) and APRI (p = 0.045).

CONCLUSION

Serum IL-34 has the potential to be a straightforward and practical biomarker that demonstrates superior performance to serum CSF-1 in the diagnosis of significant liver fibrosis in CHB patients, especially within the HBeAg-negative patients.

Macrophages Serve as Bidirectional Regulators and Potential Therapeutic Targets for Liver Fibrosis

Liver fibrosis is a dynamic pathological process in which the structure and function of the liver abnormally change due to long-term complex inflammatory reactions and chronic liver injury caused by multiple internal and external factors. Previous studies believed that the activation of hepatic stellate cells is a critical part of the occurrence and development of liver fibrosis. However, an increasing number of studies have indicated that the macrophage plays an important role as a central regulator in liver fibrosis, and it directly affects the development and recovery of liver fibrosis. Studies of macrophages and liver fibrosis in the recent 10 years will be reviewed in this paper. This review will not only clarify the molecular mechanism of liver fibrosis regulated by macrophages but also provide new strategies and methods for ameliorating and treating liver fibrosis.

A novel tumor immunotherapy-related signature for risk stratification, prognosis prediction, and immune status in hepatocellular carcinoma

Immunotherapy as a strategy to deal with cancer is increasingly being used clinically, especially in hepatocellular carcinoma (HCC). We aim to create an immunotherapy-related signature that can play a role in predicting HCC patients' survival and therapeutic outcomes. Immunotherapy-related genes were discovered first. Clinical information and gene expression data were extracted from GSE140901. By a series of bioinformatics methods to analyze, overlapping genes were used to build an immunotherapy-related signature that could contribute to predict both the prognosis of people with hepatocellular carcinoma and responder to immune checkpoint blockade therapy of them in TCGA database. Differences of the two groups in immune cell subpopulations were then compared. Furthermore, A nomogram was constructed, based on the immunotherapy-related signature and clinicopathological features, and proved to be highly predictive. Finally, immunohistochemistry assays were performed in HCC tissue and normal tissue adjacent tumors to verify the differences of the four genes expression. As a result of this study, a prognostic protein profile associated with immunotherapy had been created, which could be applied to predict patients' response to immunotherapy and may provide a new perspective as clinicians focus on non-apoptotic treatment for patients with HCC.

Hippophae rhamnoides reverses decreased CYP2D6 expression in rats with BCG-induced liver injury

In this study, we investigated the effect of Hippophae rhamnoides L. (HRP) on the activity of CYP2D6 via the CAMP/PKA/NF-κB pathway in rats with Bacille Calmette-Guerin (BCG)-induced immunological liver injury. BCG (125 mg/kg) was injected to establish the rat model of liver injury. HRP was administered intragastrically for one week as the intervention drug. Proteomics techniques were used to analyze protein expression levels, obtaining a comprehensive understanding of the liver injury process. ELISA or western blotting was used to detect specific protein levels. Dextromethorphan was detected using high-performance liquid chromatography to reflect the metabolic activity of CYP2D6. BCG downregulated the expression of CYP2D6, cAMP, PKA, IκB, and P-CREB and upregulated that of NF-κB, IL-1β, TNF-α, and CREB in the liver; HRP administration reversed these effects. Therefore, HRP may restore the metabolic function of the liver by reversing the downregulation of CYP2D6 through inhibition of NF-κB signal transduction and regulation of the cAMP/PKA/CREB/CYP2D6 pathway. These findings highlight the role of HRP as an alternative clinical drug for treating hepatitis B and other immune-related liver diseases.

Single-cell RNA sequencing reveals the heterogeneity and intercellular communication of hepatic stellate cells and macrophages during liver fibrosis

Uncontrolled and excessive progression of liver fibrosis is thought to be the prevalent pathophysiological cause of liver cirrhosis and hepatocellular cancer, and there are currently no effective antifibrotic therapeutic options available. Intercellular communication and cellular heterogeneity in the liver are involved in the progression of liver fibrosis, but the exact nature of the cellular phenotypic changes and patterns of interregulatory remain unclear. Here, we performed single-cell RNA sequencing on nonparenchymal cells (NPCs) isolated from normal and fibrotic mouse livers. We identified eight main types of cells, including endothelial cells, hepatocytes, dendritic cells, B cells, natural killer/T (NK/T) cells, hepatic stellate cells (HSCs), cholangiocytes and macrophages, and revealed that macrophages and HSCs exhibit the most variance in transcriptional profile. Further analyses of HSCs and macrophage subpopulations and ligand-receptor interaction revealed a high heterogeneity characterization and tightly interregulated network of these two groups of cells in liver fibrosis. Finally, we uncovered a profibrotic Thbs1+ macrophage subcluster, which expands in mouse and human fibrotic livers, activating HSCs via PI3K/AKT/mTOR signaling pathway. Our findings decode unanticipated insights into the heterogeneity of HSCs and macrophages and their intercellular crosstalk at a single-cell level, and may provide potential therapeutic strategies in liver fibrosis.

Ambiguous Pathogenic Roles of Macrophages in Alcohol-Associated Liver Diseases

Alcohol-associated liver disease (ALD) represents a major public health issue worldwide and is a leading etiology of liver cirrhosis. Alcohol-related liver injuries include a range of manifestations including alcoholic hepatitis (AH), simple steatosis, steatohepatitis, hepatic fibrosis, cirrhosis and liver cancer. Liver disease occurs from several pathological disturbances such as the metabolism of ethanol, which generates reactive oxygen species (ROS) in hepatocytes, alterations in the gut microbiota, and the immune response to these changes. A common hallmark of these liver affections is the establishment of an inflammatory environment, and some (broad) anti-inflammatory approaches are used to treat AH (eg, corticosteroids). Macrophages, which represent the main innate immune cells in the liver, respond to a wide variety of (pathogenic) stimuli and adopt a large spectrum of phenotypes. This translates to a diversity of functions including pathogen and debris clearance, recruitment of other immune cells, activation of fibroblasts, or tissue repair. Thus, macrophage populations play a crucial role in the course of ALD, but the underlying mechanisms driving macrophage polarization and their functionality in ALD are complex. In this review, we explore the various populations of hepatic macrophages in alcohol-associated liver disease and the underlying mechanisms driving their polarization. Additionally, we summarize the crosstalk between hepatic macrophages and other hepatic cell types in ALD, in order to support the exploration of targeted therapeutics by modulating macrophage polarization.

CREKA-modified liposomes target activated hepatic stellate cells to alleviate liver fibrosis by inhibiting collagen synthesis and angiogenesis

Activated hepatic stellate cells (HSCs) are considered the key driver of excessive extracellular matrix and abnormal angiogenesis, which are the main pathological manifestations of hepatic fibrosis. However, the absence of specific targeting moieties has rendered the development of HSC-targeted drug delivery systems a significant obstacle in the treatment of liver fibrosis. Here we have identified a notable increase in fibronectin expression on HSCs, which positively correlates with the progression of hepatic fibrosis. Thus, we decorated PEGylated liposomes with CREKA, a peptide with high affinity for fibronectin, to facilitate the targeted delivery of sorafenib to activated HSCs. The CREKA-coupled liposomes exhibited enhanced cellular uptake in the human hepatic stellate cell line LX2 and selective accumulation in CCl4-induced fibrotic liver through the recognition of fibronectin. When loaded with sorafenib, the CREKA-modified liposomes effectively suppressed HSC activation and collagen accumulation in vitro. Furthermore. in vivo results demonstrated that the administration of sorafenib-loaded CREKA-liposomes at a low dose significantly mitigated CCl4-induced hepatic fibrosis, prevented inflammatory infiltration and reduced angiogenesis in mice. These findings suggest that CREKA-coupled liposomes have promising potential as a targeted delivery system for therapeutic agents to activated HSCs, thereby providing an efficient treatment option for hepatic fibrosis. STATEMENT OF SIGNIFICANCE: In liver fibrosis, activated hepatic stellate cells (aHSCs) are the key driver of extracellular matrix and abnormal angiogenesis. Our investigation has revealed a significant elevation in fibronectin expression on aHSCs, which is positively associated with the progression of hepatic fibrosis. Thus, we developed PEGylated liposomes decorated with CREKA, a molecule with a high affinity for fibronectin, to facilitate the targeted delivery of sorafenib to aHSCs. The CREKA-coupled liposomes can specifically target aHSCs both in vitro and in vivo. Loading sorafenib into CREKA-Lip significantly alleviated CCl4-induced liver fibrosis, angiogenesis and inflammation at low doses. These findings suggest that our drug delivery system holds promise as a viable therapeutic option for liver fibrosis with minimal risk of adverse effects.

Cannabidiol alleviates perfluorooctane sulfonate-induced macrophage extracellular trap mediate inflammation and fibrosis in mice liver

As a new type of persistent organic pollutant, perfluorooctane sulphonate (PFOS) has received extensive attention worldwide. Cannabidiol (CBD) is a non-psychoactive natural cannabinoid extract that has been proved to have antioxidation, regulation of inflammation and other functions. However, the effects of PFOS on liver injury and whether CBD can alleviate PFOS-induced liver injury are still unclear. Therefore, in this study, we used CBD (10 mg/kg) and/or PFOS (5 mg/kg) to intraperitoneally inject mice for 30 days. We found that PFOS exposure led to inflammatory infiltration in the liver of mice, increased the formation of macrophage extracellular trap (MET), and promoted fibrosis. In vitro, we established a coculture system of RAW264.7, AML12 and LX-2 cells, and treated them with CBD (10 μM) and/or PFOS (200 μM). The results showed that PFOS could also induce the expression of MET, inflammation and fibrosis marker genes in vitro. Coiled-coil domain containing protein 25 (CCD25), as a MET-DNA sensor, was used to investigate its ability to regulate inflammation and fibrosis, we knocked down CCDC25 and its downstream proteins (integrin-linked kinase, ILK) by siRNA technology, and used QNZ to inhibit NF-κB pathway. The results showed that the knockdown of CCDC25 and ILK and the inhibition of NF-κB pathway could inhibit MET-induced inflammation and fibrosis marker gene expression. In summary, we found that PFOS-induced MET can promote inflammation and fibrosis through the CCDC25-ILK-NF-κB signaling axis, while the treatment of CBD showed a protective effect, and it is proved by Macromolecular docking that this protective effect is achieved by combining CBD with peptidylarginine deiminase 4 (PAD4) to alleviate the release of MET. Therefore, regulating the formation of MET and the CCDC25-ILK-NF-κB signaling axis is an innovative treatment option that can effectively reduce hepatotoxicity. Our study reveals the mechanism of PFOS-induced hepatotoxicity and provides promising insights into the protective role of CBD in this process.

Therapeutic inhibition of miR-155 attenuates liver fibrosis via STAT3 signaling

Most chronic liver diseases progress to liver fibrosis, which, when left untreated, can lead to cirrhosis and hepatocellular carcinoma. MicroRNA (miRNA)-targeted therapeutics have become attractive approaches to treat diseases. In this study, we investigated the therapeutic effect of miR-155 inhibition in the bile duct ligation (BDL) mouse model of liver fibrosis and evaluated the role of miR-155 in chronic liver fibrosis using miR-155-deficient (miR-155 knockout [KO]) mice. We found increased hepatic miR-155 expression in patients with cirrhosis and in the BDL- and CCl4-induced mouse models of liver fibrosis. Liver fibrosis was significantly reduced in miR-155 KO mice after CCl4 administration or BDL. To assess the therapeutic potential of miR-155 inhibition, we administered an rAAV8-anti-miR-155 tough decoy in vivo that significantly reduced liver damage and fibrosis in BDL. BDL-induced protein levels of transforming growth factor β (TGF-β), p-SMAD2/3, and p-STAT3 were attenuated in anti-miR-155-treated compared with control mice. Hepatic stellate cells from miR-155 KO mice showed attenuation in activation and mesenchymal marker expression. In vitro, miR-155 gain- and loss-of-function studies revealed that miR-155 regulates activation of stellate cells partly via STAT3 signaling. Our study suggests that miR-155 is the key regulator of liver fibrosis and might be a potential therapeutic target to attenuate fibrosis progression.

Mechanisms of tumor-associated macrophages affecting the progression of hepatocellular carcinoma

Tumor-associated macrophages (TAMs) are essential components of the immune cell stroma of hepatocellular carcinoma. TAMs originate from monocytic myeloid-derived suppressor cells, peripheral blood monocytes, and kupffer cells. The recruitment of monocytes to the HCC tumor microenvironment is facilitated by various factors, leading to their differentiation into TAMs with unique phenotypes. TAMs can directly activate or inhibit the nuclear factor-κB, interleukin-6/signal transducer and signal transducer and activator of transcription 3, Wnt/β-catenin, transforming growth factor-β1/bone morphogenetic protein, and extracellular signal-regulated kinase 1/2 signaling pathways in tumor cells and interact with other immune cells via producing cytokines and extracellular vesicles, thus affecting carcinoma cell proliferation, invasive and migratory, angiogenesis, liver fibrosis progression, and other processes to participate in different stages of tumor progression. In recent years, TAMs have received much attention as a prospective treatment target for HCC. This review describes the origin and characteristics of TAMs and their mechanism of action in the occurrence and development of HCC to offer a theoretical foundation for further clinical research of TAMs.

Non-alcoholic fatty liver disease: pathophysiological concepts and treatment options

The prevalence of non-alcoholic fatty liver disease (NAFLD) is continually increasing due to the global obesity epidemic. NAFLD comprises a systemic metabolic disease accompanied frequently by insulin resistance and hepatic and systemic inflammation. Whereas simple hepatic steatosis is the most common disease manifestation, a more progressive disease course characterized by liver fibrosis and inflammation (i.e. non-alcoholic steatohepatitis) is present in 10-20% of affected individuals. NAFLD furthermore progresses in a substantial number of patients towards liver cirrhosis and hepatocellular carcinoma. Whereas this disease now affects almost 25% of the world's population and is mainly observed in obesity and type 2 diabetes, NAFLD also affects lean individuals. Pathophysiology involves lipotoxicity, hepatic immune disturbances accompanied by hepatic insulin resistance, a gut dysbiosis, and commonly hepatic and systemic insulin resistance defining this disorder a prototypic systemic metabolic disorder. Not surprisingly many affected patients have other disease manifestations, and indeed cardiovascular disease, chronic kidney disease, and extrahepatic malignancies are all contributing substantially to patient outcome. Weight loss and lifestyle change reflect the cornerstone of treatment, and several medical treatment options are currently under investigation. The most promising treatment strategies include glucagon-like peptide 1 receptor antagonists, sodium-glucose transporter 2 inhibitors, Fibroblast Growth Factor analogues, Farnesoid X receptor agonists, and peroxisome proliferator-activated receptor agonists. Here, we review epidemiology, pathophysiology, and therapeutic options for NAFLD.

The crosstalking immune cells network creates a collective function beyond the function of each cellular constituent during the progression of hepatocellular carcinoma

Abundance of data on the role of inflammatory immune responses in the progression or inhibition of hepatocellular carcinoma (HCC) has failed to offer a curative immunotherapy for HCC. This is largely because of focusing on detailed specific cell types and missing the collective function of the hepatic immune system. To discover the collective immune function, we take systems immunology approach by performing high-throughput analysis of snRNAseq data collected from the liver of DIAMOND mice during the progression of nonalcoholic fatty liver disease (NAFLD) to HCC. We report that mutual signaling interactions of the hepatic immune cells in a dominant-subdominant manner, as well as their interaction with structural cells shape the immunological pattern manifesting a collective function beyond the function of the cellular constituents. Such pattern discovery approach recognized direct role of the innate immune cells in the progression of NASH and HCC. These data suggest that discovery of the immune pattern not only detects the immunological mechanism of HCC in spite of dynamic changes in immune cells during the course of disease but also offers immune modulatory interventions for the treatment of NAFLD and HCC.

Vitamin D alleviates hypothyroidism associated liver dysfunction: Histological and biochemical evidence

There is a complex correlation between thyroid hormones (THs) and liver function. Hypothyroidism as a failure of the thyroid gland to produce adequate thyroid hormones to fulfill the metabolic requirements of the body, may perturb liver structure and function. Emerging evidence suggests the protective effects of vitamin D against liver damage. Herein, this study aimed to investigate the role of vitamin D in hypothyroidism-associated liver injury. Forty male Wistar rats were classified into 4 groups: control, hypothyroid (Hypo) group received 0.05% PTU, Hypo- Vitamin D groups were given 100 and 500 IU/kg vitamin D orally via gavage for 6 weeks. Serum level of liver function including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) were measured. Malondialdehyde (MDA) level, superoxide dismutase (SOD) enzyme activity, and total thiol content were measured as oxidative stress indicators in the liver tissue. Furthermore, to estimate liver tissue fibrosis, Masson's trichrome staining was done. Our findings showed that hypothyroidism-induced liver fibrosis was associated with increased levels of ALT, AST and ALP. Though, vitamin D administration could significantly reduce the ALT, AST and ALP in the serum and suppress the accumulation of collagen fibers. Moreover, the activity of SOD and total thiol content was notably reduced, while the MDA content was significantly increased in the PTU- induced hypothyroid rats compared to the control group. Nonetheless, treatment with vitamin D improved mentioned oxidative stress markers in the Hypo-vitamin D groups. In conclusion, vitamin D due to its potential antioxidant and anti-fibrotic properties could be effective in the decrease of hypothyroidism-associated liver injury.

Chronic-binge ethanol feeding aggravates systemic dyslipidemia in Ldlr-/- mice, thereby accelerating hepatic fibrosis

Objective

Chronic ethanol consumption is known to cause alcohol-associated liver disease, which poses a global health concern as almost a quarter of heavy drinkers develop severe liver damage. Alcohol-induced liver disease ranges from a mild, reversible steatotic liver to alcoholic steatohepatitis and irreversible liver fibrosis and cirrhosis, ultimately requiring liver transplantation. While ethanol consumption is associated with dysregulated lipid metabolism and altered cholesterol homeostasis, the impact of dyslipidemia and pre-existing hypercholesterolemia on the development of alcohol-associated liver disease remains to be elucidated.

Design

To address the influence of systemic dyslipidemia on ethanol-induced liver disease, chronic-binge ethanol feeding was applied to female C57BL/6J (wild type) mice and mice deficient for the low-density lipoprotein receptor (Ldlr-/-), which display a human-like lipoprotein profile with elevated cholesterol and triglyceride levels in circulation. Respective control groups were pair-fed an isocaloric diet.

Results

Chronic-binge ethanol feeding did not alter systemic lipid levels in wild type mice. While increased systemic cholesterol levels in Ldlr-/- mice were not affected by ethanol feeding, chronic-binge ethanol diet aggravated elevated plasma triglyceride levels in Ldlr-/- mice. Despite higher circulatory triglyceride levels in Ldlr-/- mice, hepatic lipid levels and the development of hepatic steatosis were not different from wild type mice after ethanol diet, while hepatic expression of genes related to lipid metabolism (Lpl) and transport (Cd36) showed minor changes. Immunohistochemical assessment indicated a lower induction of infiltrating neutrophils in the livers of ethanol-fed Ldlr-/- mice compared to wild type mice. In line, hepatic mRNA levels of the pro-inflammatory genes Ly6g, Cd11b, Ccr2, Cxcl1 and F4/80 were reduced, indicating less inflammation in the livers of Ldlr-/- mice which was associated with reduced Tlr9 induction. While systemic ALT and hepatic MDA levels were not different, Ldlr-deficient mice showed accelerated liver fibrosis development after chronic-binge ethanol diet than wild type mice, as indicated by increased levels of Sirius Red staining and higher expression of pro-fibrotic genes Tgfb, Col1a1 and Col3a1. Ldlr-/- and wild type mice had similar plasma ethanol levels and did not show differences in the hepatic mRNA levels of Adh1 and Cyp2e1, important for ethanol metabolism.

Conclusion

Our results highlight that chronic-binge ethanol feeding enhances systemic dyslipidemia in Ldlr-/- mice which might accelerate the development of hepatic fibrosis, independent of hepatic lipid levels.

Liver metastasis from colorectal cancer: pathogenetic development, immune landscape of the tumour microenvironment and therapeutic approaches

Colorectal cancer liver metastasis (CRLM) is one of the leading causes of death among patients with colorectal cancer (CRC). Although immunotherapy has demonstrated encouraging outcomes in CRC, its benefits are minimal in CRLM. The complex immune landscape of the hepatic tumour microenvironment is essential for the development of a premetastatic niche and for the colonisation and metastasis of CRC cells; thus, an in-depth understanding of these mechanisms can provide effective immunotherapeutic targets for CRLM. This review summarises recent studies on the immune landscape of the tumour microenvironment of CRLM and highlights therapeutic prospects for targeting the suppressive immune microenvironment of CRLM.

MiR-552-3p Regulates Multiple Fibrotic and Inflammatory genes Concurrently in Hepatic Stellate Cells Improving NASH-associated Phenotypes

Non-alcoholic steatohepatitis (NASH) is a chronic liver disease characterized by hepatic steatosis, inflammation, and progressive fibrosis. Our previous study demonstrated that microRNA-552-3p (miR-552-3p) was down-regulated in the livers of patients with NASH and alleviated hepatic glycolipid metabolic disorders. However, whether miR-552-3p affects NASH progression remains unclear. In this current study, we found that hepatic miR-552-3p expression was negatively correlated with the degree of liver fibrosis and inflammation of NASH patients. Interestingly, the level of miR-552-3p was decreased during hepatic stellate cell (HSC) activation in vitro. Overexpression of miR-552-3p could not only inhibit the expression of fibrotic and inflammatory genes, but also restrain the activation of TGF-β1/Smad3 signaling pathway by down-regulating the expression of TGFBR2 and SMAD3 in HSCs, finally suppressing HSC activation. More importantly, overexpression of miR-552-3p ameliorated liver fibrosis and inflammation in two murine models: high fat/high fructose/high cholesterol diet-induced NASH model and carbon tetrachloride (CCl4)-treated liver fibrosis model. In conclusion, miR-552-3p plays a crucial role in the pathogenesis of NASH by limiting multiple fibrotic and inflammatory pathways in HSCs, which may shed light on its therapeutic potential in NASH.

Macrophage in liver Fibrosis: Identities and mechanisms

Liver fibrosis is a chronic disease characterized by the deposition of extracellular matrix and continuous loss of tissues that perform liver functions. Macrophages are crucial modulators of innate immunity and play important roles in liver fibrogenesis. Macrophages comprise heterogeneous subpopulations that exhibit different cellular functions. Understanding the identity and function of these cells is essential for understanding the mechanisms of liver fibrogenesis. According to different definitions, liver macrophages are divided into M1/M2 macrophages or monocyte-derived macrophages/Kupffer cells. Classic M1/M2 phenotyping corresponds to pro- or anti-inflammatory effects, and, therefore, influences the degree of fibrosis in later phases. In contrast, the origin of the macrophages is closely associated with their replenishment and activation during liver fibrosis. These two classifications of macrophages depict the function and dynamics of liver-infiltrating macrophages. However, neither description properly elucidates the positive or negative role of macrophages in liver fibrosis. Critical tissue cells mediating liver fibrosis include hepatic stellate cells and hepatic fibroblasts, with hepatic stellate cells being of particular interest because of their close association with macrophages in liver fibrosis. However, the molecular biological descriptions of macrophages are inconsistent between mice and humans, warranting further investigations. In liver fibrosis, macrophages can secrete various pro-fibrotic cytokines, such as TGF-β, Galectin-3 and interleukins (ILs), and fibrosis-inhibiting cytokines, such as IL10. These different secretions may be associated with the specific identity and spatiotemporal characteristics of macrophages. Furthermore, during fibrosis dissipation, macrophages may degrade extracellular matrix by secreting matrix metalloproteinases (MMPs). Notably, using macrophages as therapeutic targets in liver fibrosis has been explored. The current therapeutic approaches for liver fibrosis can by categorized as follows: treatment with macrophage-related molecules and macrophage infusion therapy. Although there have been limited studies, macrophages have shown reliable potential for liver fibrosis treatment. In this review, we focu on the identity and function of macrophages and their relationship to the progression and regression of liver fibrosis.

Activation of Kupffer cells in NAFLD and NASH: mechanisms and therapeutic interventions

Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are emerging as the leading causes of liver disease worldwide. These conditions can lead to cirrhosis, liver cancer, liver failure, and other related ailments. At present, liver transplantation remains the sole treatment option for end-stage NASH, leading to a rapidly growing socioeconomic burden. Kupffer cells (KCs) are a dominant population of macrophages that reside in the liver, playing a crucial role in innate immunity. Their primary function includes phagocytosing exogenous substances, presenting antigens, and triggering immune responses. Moreover, they interact with other liver cells during the pathogenesis of NAFLD, and this crosstalk may either delay or exacerbate disease progression. Stimulation by endogenous signals triggers the activation of KCs, resulting in the expression of various inflammatory factors and chemokines, such as NLRP3, TNF-α, IL-1B, and IL-6, and contributing to the inflammatory cascade. In the past 5 years, significant advances have been made in understanding the biological properties and immune functions of KCs in NAFLD, including their interactions with tissue molecules, underlying molecular mechanisms, signaling pathways, and relevant therapeutic interventions. Having a comprehensive understanding of these mechanisms and characteristics can have enormous potential in guiding future strategies for the prevention and treatment of NAFLD.

Neobavaisoflavone induces pyroptosis of liver cancer cells via Tom20 sensing the activated ROS signal

BACKGROUND

Neobavaisoflavone (NBIF), a natural active ingredient isolated from Psoralea, possesses anti-inflammatory, anti-cancer, and antioxidant properties; however, the anti-tumor mechanism of NBIF has not been thoroughly investigated, and the inhibitory effect and inhibitory pathway of NBIF on liver cancer are still unknown.

PURPOSE

Our study aimed to explore the effects of NBIF on hepatocellular carcinoma and its potential mechanisms.

METHODS

First, we detected the inhibition of NBIF on HCC cells by the CCK8 assay and then observed the morphological changes of the cells under the microscope. Besides, we analyzed the changes in the pyroptosis level of NBIF when inhibiting the cells through flow cytometry, immunofluorescence, and a western blot assay. Finally, we used a mouse tumor-bearing model to explore the effects of NBIF in vivo on HCCLM3 cells.

RESULTS

NBIF-treated HCC cells exhibited specific features of pyroptosis. Analysis of pyroptosis-related protein levels revealed that NBIF primarily induced pyroptosis in HCC cells via the caspase-3-GSDME signaling pathway. Then, we demonstrated that NBIF impacted the protein expression of Tom20 by producing ROS in HCC cells, hence promoting the recruitment of Bax to mitochondria, activating caspase-3, cutting GSDME, and triggering pyroptosis.

CONCLUSIONS

By activating ROS, NBIF was able to trigger pyroptosis in HCC cells, providing an experimental basis for the future study of new treatments for liver cancer.

Unraveling the Emerging Niche Role of Hepatic Stellate Cell-derived Exosomes in Liver Diseases

Hepatic stellate cells (HSCs) play an essential role in various liver diseases, and exosomes are critical mediators of intercellular communication in local and distant microenvironments. Cellular crosstalk between HSCs and surrounding multiple tissue-resident cells promotes or inhibits the activation of HSCs. Substantial evidence has revealed that HSC-derived exosomes are involved in the occurrence and development of liver diseases through the regulation of retinoid metabolism, lipid metabolism, glucose metabolism, protein metabolism, and mitochondrial metabolism. HSC-derived exosomes are underpinned by vehicle molecules, such as mRNAs and microRNAs, that function in, and significantly affect, the processes of various liver diseases, such as acute liver injury, alcoholic liver disease, nonalcoholic fatty liver disease, viral hepatitis, fibrosis, and cancer. As such, numerous exosomes derived from HSCs or HSC-associated exosomes have attracted attention because of their biological roles and translational applications as potential targets for therapeutic targets. Herein, we review the pathophysiological and metabolic processes associated with HSC-derived exosomes, their roles in various liver diseases and their potential clinical application.

Mechanical homeostasis imbalance in hepatic stellate cells activation and hepatic fibrosis

Chronic liver disease or repeated damage to hepatocytes can give rise to hepatic fibrosis. Hepatic fibrosis (HF) is a pathological process of excessive sedimentation of extracellular matrix (ECM) proteins such as collagens, glycoproteins, and proteoglycans (PGs) in the hepatic parenchyma. Changes in the composition of the ECM lead to the stiffness of the matrix that destroys its inherent mechanical homeostasis, and a mechanical homeostasis imbalance activates hepatic stellate cells (HSCs) into myofibroblasts, which can overproliferate and secrete large amounts of ECM proteins. Excessive ECM proteins are gradually deposited in the Disse gap, and matrix regeneration fails, which further leads to changes in ECM components and an increase in stiffness, forming a vicious cycle. These processes promote the occurrence and development of hepatic fibrosis. In this review, the dynamic process of ECM remodeling of HF and the activation of HSCs into mechanotransduction signaling pathways for myofibroblasts to participate in HF are discussed. These mechanotransduction signaling pathways may have potential therapeutic targets for repairing or reversing fibrosis.

The emerging importance role of m6A modification in liver disease

N6-methyladenosine (m6A) modification, as one of the most common types of inner RNA modification in eukaryotes, plays a multifunctional role in normal and abnormal biological processes. This type of modification is modulated by m6A writer, eraser and reader, which in turn impact various processes of RNA metabolism, such as RNA processing, translation, nuclear export, localization and decay. The current academic view holds that m6A modification exerts a crucial role in the post-transcriptional modulation of gene expression, and is involved in multiple cellular functions, developmental and disease processes. However, the potential molecular mechanism and specific role of m6A modification in the development of liver disease have not been fully elucidated. In our review, we summarized the latest research progress on m6A modification in liver disease, and explored how these novel findings reshape our knowledge of m6A modulation of RNA metabolism. In addition, we also illustrated the effect of m6A on liver development and regeneration to prompt further exploration of the mechanism and role of m6A modification in liver physiology and pathology, providing new insights and references for the search of potential therapeutic targets for liver disease.

Inhibition of FGFR2 Signaling by Cynaroside Attenuates Liver Fibrosis

Liver fibrosis represents a significant health hazard with a high morbidity rate and an increased risk of liver cancer. Targeting overactivated Fibroblast growth factor receptor 2 (FGFR2) is a promising strategy to counteract collagen accumulation during liver fibrosis. However, there is a shortage of drugs to specifically block the activation of FGFR2 in liver fibrosis patients. Data mining, cell validation, and animal studies showed a positive correlation between FGFR2 overexpression and liver fibrosis development. Novel FGFR2 inhibitors were screened using a microarray-based high-throughput binding analysis. The effectiveness of each candidate was validated through simulated docking, binding affinity verification, single-point mutation validation, and in vitro kinase inhibition measurements to demonstrate the ability of each inhibitor to block the catalytic pocket and reverse FGFR2 overactivation. A specific FGFR2 inhibitor, cynaroside (CYN, also known as luteoloside), was screened based on the finding that FGFR2 promotes hepatic stellate cell (HSC) activation and collagen secretion in hepatocytes. The results from cellular assays showed that CYN can inhibit FGFR2 hyperactivation resulting from its overexpression and excessive basic fibroblast growth factor (bFGF), reducing HSC activation and collagen secretion in hepatocytes. Animal experiments on a carbon tetrachloride (CCl4) mouse model and a nonalcoholic steatohepatitis mouse model indicate that CYN treatment reduces liver fibrosis during fibrosis formation. These findings suggest that CYN prevents liver fibrosis formation at the cell level and in mouse models.

Hyaluronan in liver fibrosis: basic mechanisms, clinical implications, and therapeutic targets

Hyaluronan (HA), also known as hyaluronic acid, is a glycosaminoglycan that is a critical component of the extracellular matrix (ECM). Production and deposition of ECM is a wound-healing response that occurs during chronic liver disease, such as cirrhosis. ECM production is a sign of the disease progression of fibrosis. Indeed, the accumulation of HA in the liver and elevated serum HA levels are used as biomarkers of cirrhosis. However, recent studies also suggest that the ECM, and HA in particular, as a functional signaling molecule, facilitates disease progression and regulation. The systemic and local levels of HA are regulated by de novo synthesis, cleavage, endocytosis, and degradation of HA, and the molecular mass of HA influences its pathophysiological effects. However, the regulatory mechanisms of HA synthesis and catabolism and the functional role of HA are still poorly understood in liver fibrosis. This review summarizes the role of HA in liver fibrosis at molecular levels as well as its clinical implications and discusses the potential therapeutic uses of targeting HA in liver fibrosis.

Phillygenin inhibited M1 macrophage polarization and reduced hepatic stellate cell activation by inhibiting macrophage exosomal miR-125b-5p

Liver fibrosis (LF) is an important stage in chronic liver disease development, characterized by hepatic stellate cell (HSC) activation and excessive extracellular matrix deposition. Phillygenin (PHI), an active component in the traditional Chinese medicine Forsythiae Fructus with a significant anti-inflammatory effect, has been proved to inhibit HSC activation. Macrophages can polarize to pro-inflammatory M1 phenotype and anti-inflammatory M2 phenotype, participating in LF development. Currently, Forsythiae Fructus and its many components have been proved to inhibit the inflammatory activation of macrophages. However, there is no direct evidence that PHI can regulate macrophage polarization, and the relationship between macrophage polarization and the anti-LF effect of PHI has not been studied. In this study, we found that PHI inhibited the co-expression of CD80 and CD86, and inhibited the mRNA expression and protein secretion of related inflammatory cytokines in RAW264.7 cells. For mechanism, PHI was found to inhibit the JAK1/JAK2-STAT1 and Notch1 signaling pathways. Subsequently, mHSCs were co-cultured with the conditioned media or exosomes from macrophages with different treatments. It was found that the conditioned media and exosomes from PHI-treated macrophages inhibited the expression of MMP2, TIMP1, TGF-β, α-SMA, COL1 and NF-κB in mHSCs. Moreover, through bioinformatic analysis and cell transfection, we confirmed that PHI reduced HSC activation by inhibiting the overexpression of miR-125b-5p in M1 macrophage-derived exosomes and restoring Stard13 expression in mHSCs. On the whole, PHI could inhibit M1 macrophage polarization by suppressing the JAK1/JAK2-STAT1 and Notch1 signaling pathways, and reduce HSC activation by inhibiting macrophage exosomal miR-125b-5p targeting Stard13. DATA AVAILABILITY: The raw data supporting the conclusions of this study are available in the article/Supplementary figures, and can be obtained from the first or corresponding author.

Anti-fibrotic effect of aurocyanide, the active metabolite of auranofin

Drug repositioning has gained significant attention over the past several years. The anti-rheumatoid arthritis drug auranofin has been investigated for the treatment of other diseases, including liver fibrosis. Because auranofin is rapidly metabolized, it is necessary to identify the active metabolites of auranofin that have detectable levels in the blood and reflect its therapeutic effects. In the present study, we investigated whether aurocyanide as an active metabolite of auranofin, can be used to evaluate the anti-fibrotic effects of auranofin. Incubation of auranofin with liver microsomes showed that auranofin was susceptible to hepatic metabolism. Previously, we found that the anti-fibrotic effects of auranofin are mediated via system x_c^--dependent inhibition of the NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome. Therefore, we tried to identify active metabolites of auranofin based on their inhibitory effects on system x_c^- and NLRP3 inflammasome in bone marrow-derived macrophages. Among the seven candidate metabolites, 1-thio-β-D-glycopyrano-sato-S-(triethyl-phosphine)-gold(I) and aurocyanide potently inhibited system x_c^- and NLRP3 inflammasome. A pharmacokinetics study on mice detected significant plasma levels of aurocyanide after auranofin administration. Oral administration of aurocyanide significantly prevented thioacetamide-induced liver fibrosis in mice. Moreover, the in vitro anti-fibrotic effects of aurocyanide were assessed in LX-2 cells, where aurocyanide significantly decreased the migratory ability of the cells. In conclusion, aurocyanide is metabolically stable and detectable in plasma, and has inhibitory effects on liver fibrosis, suggesting that it is a potential marker of the therapeutic effects of auranofin.

Non-Parenchymal Cells and the Extracellular Matrix in Hepatocellular Carcinoma in Non-Alcoholic Fatty Liver Disease

Hepatocellular carcinoma (HCC) in the setting of non-alcoholic fatty liver disease (NAFLD)-related cirrhosis and even in the pre-cirrhotic state is increasing in incidence. NAFLD-related HCC has a poor clinical outcome as it is often advanced at diagnosis due to late diagnosis and systemic treatment response is poor due to reduced immune surveillance. Much of the focus of molecular research has been on the pathological changes in hepatocytes; however, immune cells, hepatic stellate cells, liver sinusoidal endothelial cells and the extracellular matrix may play important roles in the pathogenesis of NAFLD-related HCC as well. Here, we review the role of non-parenchymal cells in the liver in the pathogenesis of HCC in the context of NAFLD-NASH, with a particular focus on the innate and the adaptive immune system, fibrogenesis and angiogenesis. We review the key roles of macrophages, hepatic stellate cells (HSCs), T cells, natural killer (NK) cells, NKT cells and liver sinusoidal endothelial cells (LSECs) and the role of the extracellular matrix in hepatocarcinogenesis within the steatotic milieu.

Proteomic Analysis of Hepatic Fibrosis in Human Immunodeficiency Virus-Associated Nonalcoholic Fatty Liver Disease Demonstrates Up-regulation of Immune Response and Tissue Repair Pathways

BACKGROUND

Human immunodeficiency virus (HIV)-associated nonalcoholic fatty liver disease (NAFLD) is characterized by a high prevalence of hepatic fibrosis as a strong clinical predictor of all-cause and liver-specific mortality risk.

METHODS

We leveraged data from an earlier clinical trial to define the circulating proteomic signature of hepatic fibrosis in HIV-associated NAFLD. A total of 183 plasma proteins within 2 high-multiplex panels were quantified at baseline and at 12 months (Olink Cardiovascular III; Immuno-Oncology).

RESULTS

Twenty proteins were up-regulated at baseline among participants with fibrosis stages 2-3 versus 0-1. Proteins most differentially expressed included matrix metalloproteinase 2 (P < .001), insulin-like growth factor-binding protein 7 (P = .001), and collagen α1(I) chain (P = .001). Proteins were enriched within pathways including response to tumor necrosis factor and aminopeptidase activity. Key proteins correlated directly with visceral adiposity and glucose intolerance and inversely with CD4+ T-cell count. Within the placebo-treated arm, 11 proteins differentially increased among individuals with hepatic fibrosis progression over a 12-month period (P < .05).

CONCLUSIONS

Among individuals with HIV-associated NAFLD, hepatic fibrosis was associated with a distinct proteomic signature involving up-regulation of tissue repair and immune response pathways. These findings enhance our understanding of potential mechanisms and biomarkers of hepatic fibrosis in HIV.

Role of B Cell-Activating Factor in Fibrosis Progression in a Murine Model of Non-Alcoholic Steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease all over the world. Therapeutic strategies targeting its multidirectional pathways are required. Particularly, fibrosis is closely associated with its prognosis. We previously found that B cell-activating factor (BAFF) is associated with severity of NAFLD. Here, we determined the direct in vivo role of BAFF in the development of liver fibrosis. Histological and biochemical analyses were performed using wild-type and BAFF-deficient mice. We established a murine model of non-alcoholic steatohepatitis (NASH) using carbon tetrachloride injection accompanied by high-fat/high-cholesterol diet feeding. Additionally, in vitro analysis using mouse macrophage-like cell line RAW264.7 and primary hepatic stellate cells was performed. Hepatic steatosis and inflammation, and most importantly, the progression of liver fibrosis, were ameliorated in BAFF-deficient mice compared to those wild-type mice in our model. Additionally, BAFF deficiency reduced the number of CD11c⁺ M1-type macrophages in the liver. Moreover, BAFF stimulated RAW264.7 cells to secrete nitric oxide and tumor necrosis factor α, which drove the activation of hepatic stellate cells. This indicates that BAFF plays a crucial role in NASH development and may be a promising therapeutic target for NASH.

The Ultrastructure of Hepatic Stellate Cell-Macrophage Intercellular Crosstalk as a New Morphological Insight into Phenomenon of Fibrogenesis in Pediatric Autoimmune Hepatitis

The aim of the study was the pioneering retrospective ultrastructural evaluation of respective forms of hepatic stellate cells (HSCs) and analysis of their crosstalk with other adjacent nonparenchymal cells (NPCs), especially Kupffer cells/macrophages (KCs/MPs), in pediatric autoimmune hepatitis (AIH).

METHODS

Ultrastructural assessment of the HSC population and NPCs was performed in transmission electron microscopy (TEM) using pretreatment liver biopsies from 25 children (8 boys and 17 girls) aged 4-17 with clinic-pathologically diagnosed untreated AIH.

RESULTS

Submicroscopic evaluation allowed easy identification of numerous HSCs in the form of transitory cells, i.e., T-HSCs, accompanied by signs of fibrosis. T-HSCs included cells with features of activation initiation (iHSCs) and activation perpetuation (pHSCs), indicating high HSC activation plasticity. The pHSCs were markedly elongated and mainly showed a distinct loss of lipid cytoplasmic material, expanded and dilated channels of granular endoplasmic reticulum, and linear bundles of microfilaments beneath the cell membrane. They were surrounded by usually mature collagen fibers. Frequently activated KCs/MPs adhered directly to T-HSCs. Between them, tight intercellular junctions were formed by means of point desmosomes.

CONCLUSIONS

Our qualitative TEM observations indicate a key role of T-HSCs in liver fibrogenesis in pediatric AIH, with the essential involvement of activated KCs/MPs that directly adhere to them. Tight intercellular junctions, being the ultrastructural exponent of the specific cellular mechanisms of the crosstalk between NPCs, can play a vital role in hepatic collagen fibroplasia. A better understanding of HSC population morphology at the ultrastructural level in AIH seems important not only to improve the disease morphological diagnostics but to also provide new insights into therapeutic interventions for the phenomenon of liver fibrogenesis.

Exosomes in liver fibrosis: The role of modulating hepatic stellate cells and immune cells, and prospects for clinical applications

Liver fibrosis is a global health problem caused by chronic liver injury resulting from various factors. Hepatic stellate cells (HSCs) have been found to play a major role in liver fibrosis, and pathological stimuli lead to their transdifferentiation into myofibroblasts. Complex multidirectional interactions between HSCs, immune cells, and cytokines are also critical for the progression of liver fibrosis. Despite the advances in treatments for liver fibrosis, they do not meet the current medical needs. Exosomes are extracellular vesicles of 30-150 nm in diameter and are capable of intercellular transport of molecules such as lipids, proteins and nucleic acids. As an essential mediator of intercellular communication, exosomes are involved in the physiological and pathological processes of many diseases. In liver fibrosis, exosomes are involved in the pathogenesis mainly by regulating the activation of HSCs and the interaction between HSCs and immune cells. Serum-derived exosomes are promising biomarkers of liver fibrosis. Exosomes also have promising therapeutic potential in liver fibrosis. Exosomes derived from mesenchymal stem cells and other cells exhibit anti-liver fibrosis effects. Moreover, exosomes may serve as potential therapeutic targets for liver fibrosis and hold promise in becoming drug carriers for liver fibrosis treatment.

Ongoing involvers and promising therapeutic targets of hepatic fibrosis: The hepatic immune microenvironment

Hepatic fibrosis is often secondary to chronic inflammatory liver injury. During the development of hepatic fibrosis, the damaged hepatocytes and activated hepatic stellate cells (HSCs) caused by the pathogenic injury could secrete a variety of cytokines and chemokines, which will chemotactic innate and adaptive immune cells of liver tissue and peripheral circulation infiltrating into the injury site, mediating the immune response against injury and promoting tissue reparation. However, the continuous release of persistent injurious stimulus-induced inflammatory cytokines will promote HSCs-mediated fibrous tissue hyperproliferation and excessive repair, which will cause hepatic fibrosis development and progression to cirrhosis even liver cancer. And the activated HSCs can secrete various cytokines and chemokines, which directly interact with immune cells and actively participate in liver disease progression. Therefore, analyzing the changes in local immune homeostasis caused by immune response under different pathological states will greatly enrich our understanding of liver diseases' reversal, chronicity, progression, and even deterioration of liver cancer. In this review, we summarized the critical components of the hepatic immune microenvironment (HIME), different sub-type immune cells, and their released cytokines, according to their effect on the development of progression of hepatic fibrosis. And we also reviewed and analyzed the specific changes and the related mechanisms of the immune microenvironment in different chronic liver diseases.Moreover, we retrospectively analyzed whether the progression of hepatic fibrosis could be alleviated by modulating the HIME.We aimed to elucidate the pathogenesis of hepatic fibrosis and provide the possibility for exploring the therapeutic targets for hepatic fibrosis.

Recent progress in molecular mechanisms of postoperative recurrence and metastasis of hepatocellular carcinoma

Hepatectomy is currently considered the most effective option for treating patients with early and intermediate hepatocellular carcinoma (HCC). Unfortunately, the postoperative prognosis of patients with HCC remains unsatisfactory, predominantly because of high postoperative metastasis and recurrence rates. Therefore, research on the molecular mechanisms of postoperative HCC metastasis and recurrence will help develop effective intervention measures to prevent or delay HCC metastasis and recurrence and to improve the long-term survival of HCC patients. Herein, we review the latest research progress on the molecular mechanisms underlying postoperative HCC metastasis and recurrence to lay a foundation for improving the understanding of HCC metastasis and recurrence and for developing more precise prevention and intervention strategies.

Salvianolic acid B suppresses hepatic stellate cell activation and liver fibrosis by inhibiting the NF-κB signaling pathway via miR-6499-3p/LncRNA-ROR

BACKGROUND

Long non-coding RNA (LncRNAs) have been reported to play an important role in liver fibrosis and are closely associated with hepatic stellate cell (HSC) activation. We previously found that salvianolic acid B (Sal B) improves liver fibrosis by regulating the NF-κB signaling pathway. However, whether the LncRNA, regulator of reprogramming (LncRNA-ROR) plays a role in Sal B-mediated anti-fibrosis effects via the NF-κB signaling pathway remain unclear.

PURPOSE

This study aimed to evaluate the effects of Sal B on HSC activation and liver fibrosis and investigate its mechanism from the perspective of LncRNA-ROR-mediated NF-κB signaling pathways.

METHODS

LX-2 and T6 cell lines were cultured. Animal models of liver fibrosis were established using CCl4 in male BALB/c mice. Primary HSCs were isolated from mice and cultured. Serum biochemical and liver histological analyses were performed to evaluate the effects of Sal B on liver fibrosis. The index of HSC activation and the expression of LncRNA-ROR, microRNAs (miRNAs), and inflammatory factors were determined by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) or immunofluorescence staining. Cell proliferation was measured by a Cell Counting Kit-8 (CCK-8). NF-κB signaling-associated protein levels were assessed using western blotting or immunofluorescence staining. A luciferase reporter assay was used to detect transcription activity.

RESULTS

In this study, a lower level of LncRNA-ROR was found during Sal B attenuating HSC activation in HSCs. Mechanistically, Sal B impeded the NF-κB signaling pathway to inhibit HSC proliferation and activation by downregulating LncRNA-ROR. Additionally, Sal B upregulated miR-6499-3p to target LncRNA-ROR for degradation. Functionally, Sal B treatment ameliorated CCl4-induced liver fibrosis in mice by inhibiting HSC activation.

CONCLUSION

Sal B suppresses HSC activation and liver fibrosis via regulation of miR-6499-3p/LncRNA-ROR-mediated NF-κB signaling pathway. These results reveal a new molecular mechanism of Sal B on liver fibrosis from the insight of LncRNAs.

Molecular mechanism and potential therapeutic targets of liver metastasis from gastric cancer

Gastric cancer (GC) is characterized by high invasion and poor prognosis. The occurrence of liver metastasis seriously affects advanced GC prognosis. In recent years, great progress has been made in the field of GC liver metastasis. The abnormal expression of related genes leads to the occurrence of GC liver metastasis through metastasis cascades. The changes in the liver microenvironment provide a pre-metastasis condition for GC cells to colonize and grow. The development of several potential therapeutic targets might provide new therapeutic strategies for its treatment. Therefore, we reviewed the regulatory mechanism of abnormal genes mediating liver metastasis, the effect of liver resident cells on liver metastasis, and potential therapeutic targets, hoping to provide a novel therapeutic option to improve the quality of life and prognosis of GC patients with liver metastasis.

Fatty Liver/Adipose Tissue Dual-Targeting Nanoparticles with Heme Oxygenase-1 Inducer for Amelioration of Obesity, Obesity-Induced Type 2 Diabetes, and Steatohepatitis

Persistent uptake of high-calorie diets induces the storage of excessive lipid in visceral adipose tissue. Lipids secreted from obese adipose tissue are accumulated in peripheral tissues such as the liver, pancreas, and muscle, and impair insulin sensitivity causing type 2 diabetes mellitus (T2DM). Furthermore, the accumulation of inflammatory cytokines and lipids in the liver induces apoptosis and fibrogenesis, and ultimately causes nonalcoholic steatohepatitis (NASH). To modulate obese tissue environments, it is challenged to selectively deliver inducers of heme oxygenase-1 (HO-1) to adipose tissue with the aid of a prohibitin targeting drug delivery system. Prohibitin binding peptide (PBP), an oligopeptide targeting prohibitin rich in adipose tissue, is conjugated on the surface of Hemin- or CoPP-loaded poly(lactide-co-glycolide) nanoparticles (PBP-NPs). PBP-NPs efficiently differentiate lipid storing white adipocytes into energy-generating brown adipocytes in T2DM and NASH models. In addition, PBP-NPs are found to target prohibitin overexpressed fatty liver in the NASH model and inhibit hepatic uptake of circulating lipids. Furthermore, PBP-NPs switch phenotypes of inflammatory macrophages in damaged organs and lower inflammation. Taken together, dual-targeted induction of HO-1 in fatty adipose and liver tissues is proven to be a promising therapeutic strategy to ameliorate obesity, insulin resistance, and steatohepatitis by lowering lipids and cytokines.

[Hydroxynitone suppresses hepatic stellate cell activation by inhibiting TGF-β1 phosphorylation to alleviate CCl4-induced liver fibrosis in rats]

OBJECTIVE

To investigate the effect of hydronidone on CCl4-induced liver fibrosis in rats and explore the possible mechanism.

METHODS

Sixty-six male SD rats were randomized into 5 groups, including a control group (n=10), a liver fibrosis model group (n=20), 2 hydronidone dose groups (100 and 250 mg/kg; n=12), and a pirfenidone (250 mg/kg) treatment group (n= 12). Rat models of liver fibrosis were established by subcutaneous injection of CCl4 in all but the control group. Hydronidone and pirfenidone were given daily at the indicated doses by intragastric administration for 6 weeks. After the treatments, serum samples were collected from the rats for detecting liver function parameters, and hydroxyproline content in the liver tissue was determined. Inflammation and fibrosis in the liver tissue were observed using HE staining and Sirius Red staining. In the cell experiment, human hepatic stellate cell line LX-2 was stimulated with TGF-β1 and treated with hydronidone or pirfenidone, and the expression levels of α-SMA, collagen type I and phosphorylated Smad3, phosphorylated p38, phosphorylated ERK1/2 and phosphorylated Akt were detected with Western blotting.

RESULTS

In the rat models of liver fibrosis, treatment with hydronidone obviously improved the liver functions, reduced the content of hydroxyproline in the liver tissue, and significantly alleviated liver fibrosis (P < 0.05). In LX-2 cells, hydronidone dose-dependently decreased the expression levels of α-SMA and collagen type I. In TGF- β1-stimulated cells, the phosphorylation levels of Smad3, P38, ERK, and Akt increased progressively with the extension of the treatment time, but this effect was significantly attenuated by treatment with hydronidone (P < 0.05).

CONCLUSION

Hydronidone can inhibit the phosphorylation of the proteins in the TGF-β signaling pathway, thereby preventing TGF-β1-mediated activation of hepatic stellate cells, which may be a possible mechanism by which hydronidone alleviates CCl4-induced liver fibrosis in rats.