[Adeno-associated virus-mediated hepatocyte-specific NDUFA13 overexpression protects against CCl4-induced liver fibrosis in mice by inhibiting hepatic NLRP3 activation].

OBJECTIVE: To investigate the protective effect of NDUFA13 protein against acute liver injury and liver fibrosis in mice and explore the possible mechanisms. METHODS: BALB/C mice (7 to 8 weeks old) were divided into normal group, CCl4 group, CCl4+AAV-NC group and CCl4+AAV-NDU13 group (n=18). Mouse models of liver fibrosis were established by intraperitoneal injection of CCl4 twice a week for 3, 5 or 7 weeks, and the recombinant virus AAV8-TBG-NC or AAV8-TBG-NDUFA13 was injected via the tail vein 7-10 days prior to CCl4 injection. After the treatments, pathological changes in the liver of the mice were observed using HE and Masson staining. Hepatic expression levels of NDUFA13 and α-SMA were detected with Western blotting, and the coexpression of NDUFA13 and NLRP3, TNF-α and IL-1ß, and α-SMA and collagen Ⅲ was analyzed with immunofluorescence assay. RESULTS: HE and Masson staining showed deranged liver architecture, necrotic hepatocytes and obvious inflammatory infiltration and collagen fiber deposition in mice with CCl4 injection (P < 0.001). NDUFA13 expression markedly decreased in CCl4-treated mice (P < 0.001), while a significant reduction in inflammatory aggregation and fibrosis was observed in mice with AAV-mediated NDUFA13 overexpression (P < 0.001). In CCl4+AAV-NDU13 group, immunofluorescence assay revealed markedly weakened activation of NLRP3 inflammasomes (P < 0.001), significantly decreased TNF-α and IL-1ß secretion (P < 0.001), and inhibited hepatic stellate cell activation (P < 0.05) and collagen formation in the liver (P < 0.001). CONCLUSION: Mitochondrial NDUFA13 overexpression in hepatocytes protects against CCl4- induced liver fibrosis in mice by inhibiting activation of NLRP3 signaling.

Single-Cell Transcriptome Analysis Identified Core Genes and Transcription Factors in Mesenchymal Cell Differentiation during Liver Cirrhosis.

BACKGROUND: Mesenchymal cells, including hepatic stellate cells (HSCs), fibroblasts (FBs), myofibroblasts (MFBs), and vascular smooth muscle cells (VSMCs), are the main cells that affect liver fibrosis and play crucial roles in maintaining tissue homeostasis. The dynamic evolution of mesenchymal cells is very important but remains to be explored for researching the reversible mechanism of hepatic fibrosis and its evolution mechanism of hepatic fibrosis to cirrhosis. METHODS: Here, we analysed the transcriptomes of more than 50,000 human single cells from three cirrhotic and three healthy liver tissue samples and the mouse hepatic mesenchymal cells of two healthy and two fibrotic livers to reconstruct the evolutionary trajectory of hepatic mesenchymal cells from a healthy to a cirrhotic state, and a subsequent integrative analysis of bulk RNA sequencing (RNA-seq) data of HSCs from quiescent to active (using transforming growth factor ß1 (TGF-ß1) to stimulate LX-2) to inactive states. RESULTS: We identified core genes and transcription factors (TFs) involved in mesenchymal cell differentiation. In healthy human and mouse livers, the expression of NR1H4 and members of the ZEB families (ZEB1 and ZEB2) changed significantly with the differentiation of FB into HSC and VSMC. In cirrhotic human livers, VSMCs transformed into HSCs with downregulation of MYH11, ACTA2, and JUNB and upregulation of PDGFRB, RGS5, IGFBP5, CD36, A2M, SOX5, and MEF2C. Following HSCs differentiation into MFBs with the upregulation of COL1A1, TIMP1, and NR1H4, a small number of MFBs reverted to inactivated HSCs (iHSCs). The differentiation trajectory of mouse hepatic mesenchymal cells was similar to that in humans; however, the evolution trajectory and proportion of cell subpopulations that reverted from MFBs to iHSCs suggest that the mouse model may not accurately reflect disease progression and outcome in humans. CONCLUSIONS: Our analysis elucidates primary genes and TFs involved in mesenchymal cell differentiation during liver fibrosis using scRNA-seq data, and demonstrated the core genes and TFs in process of HSC activation to MFB and MFB reversal to iHSC using bulk RNA-seq data of human fibrosis induced by TGF-ß1. Furthermore, our findings suggest promising targets for the treatment of liver fibrosis and provide valuable insights into the molecular mechanisms underlying its onset and progression.

Schisantherin A protects hepatocyte via upregulating DDAH1 to ameliorate liver fibrosis in mice.

BACKGROUND: Hepatic fibrosis is the pivotal determinant in the progression of chronic liver diseases towards cirrhosis or advanced stages. Studies have shown that Schisantherin A (Sin A), the primary active compound from Schizandra chinensis (Turcz.) Baill., exhibits anti-hepatic fibrosis effects. However, the mechanism of Sin A in liver fibrosis remain unclear. PURPOSE: To examine the effects and underlying mechanism of Sin A on hepatic fibrosis. STUDY DESIGN AND METHODS: The effects and mechanism of Sin A were investigated using liver fibrosis mouse models induced by carbon tetrachloride (CCl4) or dimethylnitrosamine (DMN), as well as H2O2-induced hepatocyte injury in vitro. RESULTS: Sin A treatment ameliorated hepatocyte injury, inflammation, hepatic sinusoidal capillarization, and hepatic fibrosis in both CCl4-induced and DMN-induced mice. Sin A effectively reversed the reduction of DDAH1 expression, the p-eNOS/eNOS ratio and NO generation and attenuated the elevation of hepatic ADMA level induced by CCl4 and DMN. Knockdown of DDAH1 in hepatocytes not only triggered hepatocyte damage, but it also counteracted the effect of Sin A on protecting hepatocytes in vitro. CONCLUSION: Our findings indicate that Sin A ameliorates liver fibrosis by upregulating DDAH1 to protect against hepatocyte injury. These results provide compelling evidence for Sin A treatment in liver fibrosis.

The combination of tetracyclines effectively ameliorates liver fibrosis via inhibition of EphB1/2.

Eph receptor tyrosine kinase EphB1/2 contributes to the development of liver fibrosis, suggesting the rationale that EphB1/2 inhibitors may be effective in liver fibrosis therapy. Since tetracycline antibiotics were recently demonstrated as EphB kinase inhibitors, in present study we investigated their therapeutic potential against liver fibrosis. Our results showed that the tetracycline combination of demeclocycline (D), chlortetracycline (C), and minocycline (M) inhibited the activation of hepatic stellate cells (HSCs) in vitro and alleviated CCl4-induced animal model of liver fibrosis in vivo. Mechanistically, DCM combination inhibited EphB1/2 phosphorylation and subsequent activation of the MAPK signaling. Moreover, we found that short-term and low-dose DCM combination treatment decreased tissue inflammation and improved liver fibrosis in mice. Thus, our study indicates that tetracyclines may be repurposed for the treatment of liver fibrosis.

Metabolomics reveals that chronic restraint stress alleviates carbon tetrachloride-induced hepatic fibrosis through the INSR/PI3K/AKT/AMPK pathway.

Hepatic fibrosis (HF) could be developed into liver cirrhosis or even hepatocellular carcinoma. Stress has an important role in the occurrence and development of various considerable diseases. However, the effect of a certain degree stress on HF is still controversial. In our study, stress was simulated with regular chronic restraint stress (CRS) and HF model was induced with CCl4 in mice. We found that CRS was able to attenuate CCl4-induced liver injury and fibrosis in mice. Surprisingly, behavioral analysis showed that the mice in the HF group exhibited depression-like behavior. Further, the metabolomic analysis revealed that 119 metabolites and 20 metabolic pathways were altered in mice liver, especially the betaine metabolism pathway. Combined with the results of Ingenuity Pathway Analysis (IPA), the key proteins INSR, PI3K, AKT, and p-AMPK were identified and verified, and the results showed that CRS could upregulate the protein levels and mRNA expression of INSR, PI3K, AKT, and p-AMPK in liver tissues of HF mice. It suggested that CRS alleviated CCl4-induced liver fibrosis in mice through upregulation of the INSR/PI3K/AKT/AMPK pathway. Proper stress might be a potential therapeutic strategy for the treatment of chronic liver disease, which provided new insights into the treatment of HF. KEY MESSAGES: Chronic restraint stress mitigated CCl4-induced liver injury and hepatic fibrosis. CCl4-induced liver fibrosis could cause depression-like behavior. Chronic restraint stress altered metabolomic profiles in hepatic fibrosis mice, especially the betaine metabolism pathway. Chronic restraint stress increased betaine levels in liver tissue. Chronic restraint stress regulated the INSR/PI3K/AKT/AMPK signaling pathway in hepatic fibrosis mice.

Ganoderma lucidum ethanol extracts ameliorate hepatic fibrosis and promote the communication between metabolites and gut microbiota g_Ruminococcus through the NF-κB and TGF-ß1/Smads pathways.

ETHNOPHARMACOLOGICAL RELEVANCE: Ganoderma lucidum, a traditional edible medicinal mushroom, has been widely reported to improve liver diseases as a dietary intervention for people. Ganoderma lucidum extracts, primarily total triterpenoids (GLTTs), are one of the bioactive ingredients that have excellent beneficial effects on hepatic fibrosis. Therefore, its prevention and reversal are particularly critical due to the increasing number of patients with chronic liver diseases worldwide. AIM OF THE STUDY: The study aimed to evaluate whether GLTTs had a hepatoprotective effect against hepatic fibrosis through metabolic perturbations and gut microbiota changes and its underlying mechanisms. MATERIALS AND METHODS: The compound compositions of GLTTs were quantified, and carbon tetrachloride (CCl4)-induced hepatic fibrosis rats were used to investigate the cause of the improvement in various physiological states with GLTTs treatment, and to determine whether its consequent effect was associated with endogenous metabolites and gut microbiota using UPLC-Q-TOF-MSE metabolomics and 16S rRNA gene sequencing technology. RESULTS: GLTTs alleviated physical status, reduced liver pathological indicators, proinflammatory cytokines, and deposition of hepatic collagen fibers via regulating the NF-κB and TGF-ß1/Smads pathways. The untargeted metabolomics analysis identified 16 potential metabolites that may be the most relevant metabolites for gut microbiota dysbiosis and the therapeutic effects of GLTTs in hepatic fibrosis. Besides, although GLTTs did not significantly affect the α-diversity indexes, significant changes were observed in the composition of microflora structure. In addition, Spearman analysis revealed strong correlations between endogenous metabolites and gut microbiota g_Ruminococcus with hepatic fibrosis. CONCLUSION: GLTTs could provide a potential target for the practical design and application of novel functional food ingredients or drugs in the therapy of hepatic fibrosis.

Aloin Attenuates Oxidative Stress, Inflammation, and CCl4-Induced Liver Fibrosis in Mice: Possible Role of TGF-ß/Smad Signaling.

Liver fibrosis refers to the excessive buildup of extracellular matrix (ECM) components in liver tissue. It is considered a pathological response to liver damage for which there is no effective treatment. Aloin, an anthraquinone compound isolated from the aloe plant, has shown good pharmacological effects in the treatment of gastric cancer, ulcerative colitis, myocardial hypertrophy, traumatic brain injury, and other diseases; however, its specific impact on liver fibrosis remains unclear. To address this gap, we conducted a study to explore the mechanisms underlying the potential antifibrotic effect of aloin. We constructed a mouse liver fibrosis model using carbon tetrachloride (CCl4) dissolved in olive oil as a modeling drug. Additionally, a cellular model was developed by using transforming growth factor ß1 (TGF-ß1) as a stimulus applied to hepatic stellate cells. After aloin intervention, serum alanine aminotransferase, hepatic hydroxyproline, and serum aspartate aminotransferase were reduced in mice after aloin intervention compared to CCl4-mediated liver injury without aloin intervention. Aloin relieved the oxidative stress caused by CCl4 via reducing hepatic malondialdehyde in liver tissue and increasing the level of superoxide dismutase. Aloin treatment decreased interleukin (IL)-1ß, IL-6, and tumor necrosis factor-α and increased the expression of IL-10, which inhibited the inflammatory response in liver injury. In addition, aloin inhibited the activation of hepatic stellate cells and reduced the level of α-smooth muscle actin (α-SMA) and collagen type I. In cell and animal experiments, aloin attenuated liver fibrosis, acting through the TGF-ß/Smad2/3 signaling pathway, and mitigated CCl4- and TGF-ß1-induced inflammation. Thus, the findings of this study provided theoretical data support and a new possible treatment strategy for liver fibrosis.

Triptolide attenuates CCL4-induced liver fibrosis by regulating the differentiation of CD4+ T cells in mice.

Liver fibrosis is a major global health issue, and immune dysregulation is a main contributor. Triptolide is a natural immunosuppressive agent with demonstrated effectiveness in ameliorating liver fibrosis, but whether it exerts anti-liver fibrotic effects via immunoregulation remains obscure. In this study, first, by employing a CCL4-induced liver fibrosis mouse model, we demonstrated that triptolide could alleviate pathological damage to liver tissue and attenuate liver function damaged by CCL4. In addition, triptolide inhibited the expression of liver fibrotic markers such as hydroxyproline, collagen type IV, hyaluronidase, laminin, and procollagen type III, and the protein expression of α-SMA in CCL4-induced liver fibrosis. Second, with the help of network pharmacology, we predicted that triptolide's anti-liver fibrotic effects might occur through the regulation of Th17, Th1, and Th2 cell differentiation, which indicated that triptolide might mitigate liver fibrosis via immunoregulation. Finally, multiplex immunoassays and flow cytometry were adopted to verify this prediction. The results suggested that triptolide could reverse the aberrant expression of inflammatory cytokines caused by CCL4 and regulate the differentiation of Th1, Th2, Th17, and Treg cells. In conclusion, triptolide could attenuate CCL4-induced liver fibrosis by regulating the differentiation of CD4+ T cells. The results obtained in this study extended the application of triptolide and introduced a new mechanism of triptolide's anti-liver fibrotic effects.

Empagliflozin suppresses hedgehog pathway, alleviates ER stress, and ameliorates hepatic fibrosis in rats.

Worldwide mortality from hepatic fibrosis remains high, due to hepatocellular carcinoma and end stage liver failure. The progressive nature of hepatic fibrosis from inflammation to cicatrized tissues warrants subtle intervention with pharmacological agents that hold potential. Empagliflozin (Empa), a novel hypoglycemic drug with antioxidant and anti-inflammatory properties, has lately been proposed to have additional antifibrotic activities. In the current study, we examined the antifibrotic effect of the Empa through modulating the activity of hepatic stellate cells by hedgehog (Hh) pathway. We also assessed the markers of inflammatory response and endoplasmic reticulum (ER) stress. Male Albino rats were treated with either CCl4 (0.4 mg/kg twice/week) and/or Empa (10 mg/kg/day) for eight weeks. In this study, CCl4 rats had active Hh signaling as indicated by overexpression of Patched 1, Smoothened and Glioblastoma-2. CCl4 induced ER stress as CHOP expression was upregulated and ERAD was downregulated. CCl4-induced inflammatory response was demonstrated through increased levels of TNF-α, IL-6 and mRNA levels of IL-17 while undetectable expression of IL-10. Conversely, Empa elicited immunosuppression, suppressed the expression of Hh markers, and reversed markers of ER stress. In conclusion, Empa suppressed CCl4-induced Hh signaling and proinflammatory response, meanwhile embraced ER stress in the hepatic tissues, altogether provided hepatoprotection.

Kaempferol attenuates carbon tetrachloride (CCl4)-induced hepatic fibrosis by promoting ASIC1a degradation and suppression of the ASIC1a-mediated ERS.

BACKGROUND: Kaempferol is a flavonoid derived from the herb, Kaempferia galanga L., in addition to exhibiting a wide range of pharmacological properties, kaempferol is also an anti-inflammatory, anti-lipid metabolizing, and anti-oxidative stress agent. The underlying molecular mechanisms of its effects on vascular endothelial growth factor (VEGF) secretion and activation of hepatic stellate cells (HSCs) are yet unknown. Activated HSCs induces VEGF release and extracellular matrix (ECM) accumulation which are important factors in hepatic fibrosis. PURPOSE: Our aim is to explore how kaempferol may affect hepatic fibrosis and the mechanisms behind its effects. METHODS: The in vivo model was Sprague-Dawley rats induced with carbon tetrachloride (CCl4). Histological staining was used to observe histological features of the liver. The levels of (alanine aminotransferase) ALT and (aspartate aminotransferase) AST were detected by the corresponding kits. Platelet-derived growth factor (PDGF) was used to stimulate the HSC-T6 rat hepatic stellate cells. The mechanisms underlying this process were investigated using a variety of molecular approaches, including immunofluorescence, RT-qPCR, and western blotting. Moreover, intracellular Ca2+ were observed by laser confocal microscope. RESULTS: It was found that kaempferol significantly reduced the expression of ASIC1a, VEGF, α-SMA and Collagen-I proteins in a model of CCl4-induced hepatic fibrosis in rats. In HSC-T6, kaempferol inhibits activation of HSCs by decreasing expression of ASIC1a, eIF2α, p-eIF2α and ATF-4. Laser confocal fluorescence showed that kaempferol inhibited Ca2+ influx and reduced Ca2+ concentration around the endoplasmic reticulum. Molecular docking and cellular thermal shift assay (CETSA) results further indicated that kaempferol interacted with ASIC1a. We found that kaempferol may promote the degradation of ASIC1a and inhibited ASIC1a- mediated upregulation of ERS. CONCLUSION: The data from our in vivo experiments demonstrate that kaempferol effectively attenuates hepatic fibrosis. In vitro studies we further propose a novel mechanism of kaempferol against hepatic fibrosis which can interact with ASIC1a and promote ASIC1a degradation while inhibiting the activation and VEGF release of HSCs by suppressing the ASIC1a-eIF2α-ATF-4 signaling pathway.

Protective effect of water extracts of Veronicastrum latifolium (Hemsl.) Yamazaki on carbon tetrachloride-induced liver fibrosis in mice and its effect on intestinal flora.

Liver fibrosis refers to a reversible event of repair and reconstruction following injury due to various etiologies, and its continuous development will lead to cirrhosis and liver cancer. Abnormal alterations in intestinal microbiota can hasten the development of hepatic fibrosis and damage. Veronicastrum latifolium (Hemsl.) Yamazaki (VLY) is a classic drug applied extensively for managing acute and chronic hepatitis, liver cirrhosis and ascites in ethnic minority areas of Guizhou Province, China, which possesses broad-spectrum pharmacological activities. In view of the crucial role of intestinal microbiota in the development of liver fibrosis, the present study attempted to investigate the effects of VLY aqueous extract on ameliorating CCl4-elicited liver fibrosis in mice and on intestinal microbiota and to explore its possible mechanism. Phytochemical analysis showed that VLY water extract contained a variety of components, particularly rich in organic acids and their derivatives, flavonoids, phenolic acids, nucleotides and their derivatives, carbohydrates and other compounds. VLY water extract remarkably alleviated CCl4-induced liver damage and fibrosis in mice, improved liver histology, and improved liver function abnormalities. VLY water extract also inhibited the activation of hepatic stellate cells and invasion of intrahepatic inflammatory cells. Additionally, sequencing the 16 s rDNA gene revealed that VLY water extract changed the intestinal microbiota composition in liver fibrotic mice. It elevated the Firmicutes/Bacteroidota ratio and enriched the relative Lactobacillus richness, which is capable of mitigating fibrosis and inflammation in impaired liver. In summary, through modulation of inflammation and intestinal microbiota, VLY water extract can reduce the CCl4-elicited liver fibrosis.

Farnesoid X receptor activation is required for the anti-inflammatory and anti-oxidative stress effects of Alisol B 23-acetate in carbon tetrachloride-induced liver fibrosis in mice.

Previous studies have shown that Alisol B 23-acetate (23ABA) had potent liver-protection effects, however, its roles and potential mechanisms in carbon tetrachloride (CCl4)-induced liver fibrosis remain to be determined. The present study aimed to investigate the effects of 23ABA on CCl4-induced liver fibrosis and tried to elucidate the underlying mechanisms by focusing on regulating of farnesoid X receptor (FXR). In vivo study found that 23ABA alleviated the CCl4-induced liver injury, and showed no obvious systemic toxicity on mice. 23ABA inhibited the collagen production, decreased sera levels of hyaluronic acid (HA) and procollagen type III (PC-III), lowered mRNA expression of α-smooth muscle actin (α-SMA), fibronectin, collagen I and collagen III in livers of mice. 23ABA inhibited the mRNA expressions and the sera levels of interleukin-6 (IL-6), IL-1ß, and tumor necrosis factor-α (TNF-α), as well as decreased the expression of cyclooxygenase 2 (COX-2) in fibrotic livers of mice. Besides, 23ABA decreased levels of reactive oxygen species (ROS) and malondialdehyde (MDA), increased glutathione (GSH) level, enhanced activities of superoxide dismutase (SOD) and glutathione reductase (GR) as well as increased mRNA expression of nuclear factor-E2-related factor 2 (Nrf2), glutamate-cysteine ligase, catalytic subunit (GCLC) and glutamate-cysteine ligase, modifier subunit (GCLM). Further study showed that the anti-liver injury and anti-fibrotic effects of 23ABA were abrogated by FXR antagonist guggulsterone (GS) in vivo. In addition, the inhibition effects of 23ABA on liver inflammation and oxidative stress were also weakened by treatment with GS in CCl4-induced fibrotic mice livers. In conclusion, the protective effects of 23ABA against CCl4-induced liver injury and fibrosis, due to FXR-mediated regulation of liver inflammation and oxidative stress.

Axitinib attenuates the progression of liver fibrosis by restoring mitochondrial function.

Liver fibrosis can progress to cirrhosis and hepatocellular carcinoma, which may eventually lead to liver failure and even death. No direct anti-fibrosis drugs are available at present. Axitinib is a new generation of potent multitarget tyrosine kinase receptor inhibitors, but its role in liver fibrosis remains unclear. In this study, a CCl4-induced hepatic fibrosis mouse model and a TGF-ß1-induced hepatic stellate cell model were used to explore the effect and mechanism of axitinib on hepatic fibrosis. Results confirmed that axitinib could alleviate the pathological damage of liver tissue induced by CCl4 and inhibit the production of glutamic-oxalacetic transaminase and glutamic-pyruvic transaminase. It also inhibited collagen and hydroxyproline deposition and the protein expression of Col-1 and α-SMA in CCl4-induced liver fibrosis. In addition, axitinib inhibited the expression of CTGF and α-SMA in TGF-ß1-induced hepatic stellate cells. Further studies showed that axitinib inhibited mitochondrial damage and reduced oxidative stress and NLRP3 maturation. The use of rotenone and antimycin A confirmed that axitinib could restore the activity of mitochondrial complexes I and III, thereby inhibiting the maturation of NLRP3. In summary, axitinib inhibits the activation of HSCs by enhancing the activity of mitochondrial complexes I and III, thereby alleviating the progression of liver fibrosis. This study reveals the strong potential of axitinib in the treatment of liver fibrosis.

The Effect of Royal Jelly on Telomere Length and Some Biochemical Parameters in Wistar Albino Rats with Liver Damage Caused by Carbon Tetrachloride.

Royal jelly (RJ) is a natural bee product that has been used for therapeutic purposes since ancient times. The therapeutic properties of this product, which has rich biological content, are still being investigated with new approaches. In this study, the effect of RJ on telomere length, some antioxidant parameters, and lipid profile was examined. This study will contribute to the literature as it is the first to evaluate the effect of RJ on the length of telomeres in damaged liver tissues. In the study, the levels of serum triglyceride, total cholesterol (TC), high-density lipoprotein cholesterol, low-density lipoprotein cholesterol (LDL-C), aspartate transaminase (AST), alanine transaminase (ALT), telomerase, 8'-hydroxy-2'-deoxyguanosine (8-OHdG), and paraoxonase-1 (PON1) were investigated with enzyme-linked immunosorbent assay method and telomere lengths were investigated by real-time quantitative polymerase chain reaction. The increased TC, LDL-C levels, and AST and ALT activities in the serum after carbon tetrachloride (CCl4) administration approached the control level after RJ administration. PON1 activity decreased in groups with CCl4. PON1 activity increased after RJ administration. The level of 8-OHdG, which increased groups with CCl4, decreased after RJ administration. According to the results of telomere length analysis in liver tissues, telomere lengths in damaged tissues were significantly shortened with CCl4 application and increased with RJ application. Based on the findings of the study, it was concluded that RJ may have therapeutic effects on telomere lengths and some biochemistry parameters.

Peptides from Antarctic krill (Euphausia superba) ameliorate acute liver injury in mice induced by carbon tetrachloride via activating the Nrf2/HO-1 pathway.

This study aimed to evaluate the hepatoprotective effects of peptides from Antarctic krill (AKP) on carbon tetrachloride (CCl4)-induced acute liver injury (ALI) in mice and the underlying molecular mechanisms. ICR mice were pretreated with AKP (500 mg kg-1, i.g.) and silybin (30 mg kg-1, i.g.) for 15 days before CCl4 (0.25 mL per kg BW, i.p.) injection. To assess hepatocellular damage and molecular indices, the serum and liver tissue were evaluated at harvest. The results showed that AKP pretreatment remarkably attenuated CCl4-induced liver injury, which was identified by the decrease in serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST), alleviation of hepatocyte necrosis, and inhibition of the levels of the pro-inflammatory factors TNF-α and IL-1ß compared to those for silymarin. AKP pretreatment also enhanced the redox balance by reducing the concentrations of MDA and 8-iso-PG and increasing the activities of SOD, GSH and GSH-PX in the liver of mice. In addition, AKP upregulated oxidative stress-related mRNA expressions of Nrf2, Keap1, HO-1, and NQO1 and further activated the protein expression on the Nrf2/HO-1 singling pathway. In summary, AKP might be a promising hepatoprotective nutraceutical against ALI and its underlying mechanisms are associated with activation of the Nrf2/HO-1 pathway.

CD14 is not required for carbon tetrachloride-induced hepatic inflammation and fibrosis with or without lipopolysaccharide challenge.

Binding of lipopolysaccharide (LPS) to CD14 is required for its cellular effects via TLR4. A role of LPS/TLR4-mediated signaling in activated hepatic stellate cells (aHSCs), the major fibrogenic cells, in liver fibrosis has been reported. We investigated effects of LPS on carbon tetrachloride (CCl4)-induced fibrosis in CD14-knockout (KO) mice in vivo, and culture-activated HSCs in vitro. CCl4 (biweekly; 4 weeks)-treated wild type (WT) and CD14-KO mice were challenged with single LPS administration for 24 h. Liver injury, inflammation and fibrosis were determined. Culture-activated HSCs from WT or CD14-KO mice were stimulated with LPS. Parameters of fibrogenic activity (expression of collagen1a1 [Col1a1], α-smooth muscle actin [αSMA] and TGFß1) and inflammatory cytokines/chemokines were measured. CCl4 treatment caused similar liver injury and fibrosis in WT and CD14-KO mice. LPS increased liver injury and inflammation similarly in CCl4-treated WT and CD14-KO mice, but downregulated Timp1 and upregulated Mmp13. LPS elicited similar NFκB activation and inflammatory response in WT and CD14-KO aHSCs. LPS similarly downregulated Acta2 (encodes αSMA), Pdgfrb, Col1a1 and Mmp13 expression but did not affect Timp1 expression in WT and CD14-KO aHSCs. LPS did not alter Tgfb1 but increased expression of decorin (Dcn) (inhibitor of TGFß1) expression in WT and CD14-KO aHSCs. The results indicate that the effects of LPS on HSCs are CD14-independent, and CD14 is not required for hepatic fibrosis. LPS-induced down-modulation of fibrogenic markers in aHSCs is also CD14-independent.

Hepatocyte-specific knockout of HIF-2α cannot alleviate carbon tetrachloride-induced liver fibrosis in mice.

Background: The effects of hypoxia inducible factor-2α (HIF-2α) deficiency on liver fibrosis have not been demonstrated in a fibrosis model induced by carbon tetrachloride (CCl4). We aimed to examine whether hepatocyte-specific HIF-2α deletion could ameliorate CCl4-induced liver fibrosis in mice. Methods: Hepatocyte-specific HIF-2α knockout mice were created using an albumin promoter-driven Cre recombinase. HIF-2α knockout (KO) mice and floxed control wild-type (WT) mice were fed a normal diet (ND) and received either twice weekly intraperitoneal injections of CCl4 solution (CCl4 dissolved in olive oil) or the corresponding amount of olive oil for 8 weeks. The indicators of liver function, glucose and lipid metabolism, and liver histology were compared among the different groups. Results: Hepatocyte-specific HIF-2α knockout had no effect on the growth, liver function, glucose or lipid metabolism in mice. CCl4-treated KO and WT mice had a similar pattern of injury and inflammatory cell infiltration in the liver. Quantification of Masson staining, α-smooth muscle actin (α-SMA) immunohistochemistry, and the hydroxyproline (HYP) content revealed similar liver fibrosis levels between KO and WT mice injected intraperitoneally with CCl4. Immunohistochemistry analysis suggested that HIF-2α was mainly expressed in the portal area and hepatic sinusoids but not in hepatocytes. Bioinformatics analyses further indicated that HIF-2α expression was neither liver specific nor hepatocyte specific, and the effect of HIF-2α in hepatocytes on liver fibrosis may not be as important as that in liver sinuses. Conclusions: Hepatocyte HIF-2α expression may not be a key factor in the initiation of liver fibrogenesis, and hepatocyte-specific deletion of HIF-2α may not be the ideal therapeutic strategy for liver fibrosis.

Glaucocalyxin A attenuates carbon tetrachloride-induced liver fibrosis and improves the associated gut microbiota imbalance.

Liver fibrosis refers to the pathophysiological process of dysplasia on the connective tissue of the liver, caused by a variety of pathogenic factors. Glaucocalyxin A (GLA) has anticoagulation, antibacterial, anti-inflammation, antioxidant and antitumour properties. However, whether GLA ameliorates liver fibrosis or not is still unclear. In this study, a liver fibrosis model was established using male C57BL/6 mice. The mice were treated with 5 and 10 mg/kg GLA via intraperitoneal injection, respectively. The ones that were treated with 5 mg/kg OCA were used as the positive control group. The levels of liver function, liver fibrosis biomarkers and liver pathological changes were then evaluated. We also explored the effects of GLA on inflammatory response and liver cell apoptosis. In addition, we investigated the gut microbiota mechanisms of GLA on liver fibrosis. The results from this study that GLA could significantly decrease the level of liver function (AST, ALT, TBA) and liver fibrosis (HA, LN, PC-III, IV-C). On the other hand, a significant decrease in inflammation levels (IL-1ß, TNF-α) were also noted. GLA also improves CCl4-induced pathological liver injuries and collagen deposition, in addition to decreasing apoptosis levels. In addition, an increase in the ratio of Bacteroidetes and Firmicutes in liver disease was also observed. GLA also improves the gut microbiota. In conclusion, GLA attenuates CCl4-induced liver fibrosis and improves the associated gut microbiota imbalance.

Engineered fibrotic liver-targeted truncated transforming growth factor ß receptor type II variant for superior anti-liver fibrosis therapy.

Truncated transforming growth factor ß receptor type II (tTßRII) is a promising anti-liver fibrotic candidate because it serves as a trap for binding excessive TGF-ß1 by means of competing with wild type TßRII (wtTßRII). However, the widespread application of tTßRII for the treatment of liver fibrosis has been limited by its poor fibrotic liver-homing capacity. Herein, we designed a novel tTßRII variant Z-tTßRII by fusing the platelet-derived growth factor ß receptor (PDGFßR)-specific affibody ZPDGFßR to the N-terminus of tTßRII. The target protein Z-tTßRII was produced using Escherichia coli expression system. In vitro and in vivo studies showed that Z-tTßRII has a superior specific fibrotic liver-targeting potential via the engagement of PDGFßR-overexpressing activated hepatic stellate cells (aHSCs) in liver fibrosis. Moreover, Z-tTßRII significantly inhibited cell migration and invasion, and downregulated fibrosis- and TGF-ß1/Smad pathway-related protein levels in TGF-ß1-stimiluated HSC-T6 cells. Furthermore, Z-tTßRII remarkably ameliorated liver histopathology, mitigated the fibrosis responses and blocked TGF-ß1/Smad signaling pathway in CCl4-induced liver fibrotic mice. More importantly, Z-tTßRII exhibits a higher fibrotic liver-targeting potential and stronger anti-fibrotic effects than either its parent tTßRII or former variant BiPPB-tTßRII (PDGFßR-binding peptide BiPPB modified tTßRII). In addition, Z-tTßRII shows no significant sign of potential side effects in other vital organs in liver fibrotic mice. Taken together, we conclude that Z-tTßRII with its a high fibrotic liver-homing potential, holds a superior anti-fibrotic activity in liver fibrosis in vitro and in vivo, which may be a potential candidate for targeted therapy for liver fibrosis.

Dietary oxidized frying oil activates hepatic stellate cells and accelerates the severity of carbon tetrachloride- and thioacetamide-induced liver fibrosis in mice.

Deep-frying is a common cooking practice worldwide, and after repeated heating's, the oil undergoes various chemical reactions, including hydrolysis, polymerization, lipid oxidation, and the Maillard reaction. Studies have pointed out that oxidized dietary frying oil may cause teratogenesis in mice and increase cancer and cardiovascular risks. The liver is the main organ involved in dietary nutrient catabolism, detoxification, bile production, and lipid metabolism. Nevertheless, the effects of oxidized frying oil exposure on the activation of hepatic stellate cells (HSCs) and liver fibrosis are still unclear. In this study, we showed that exposure to oxidized frying oil enhanced the sensitivity of HSCs to transforming growth factor (TGF)-ß1-induced α-smooth muscle actin (α-SMA), collagen 1a2, collagen 1a1, metalloproteinase-2, and phosphorylated smad2/3 activation. In both carbon tetrachloride (CCl4)- and thioacetamide (TAA)-induced liver fibrosis mouse models, we showed that long-term administration of a 10% fried oil-containing diet significantly upregulated fibrogenesis genes expression and deposition of hepatic collagen. Furthermore, long-term fried oil exposure not only promoted macrophage infiltration and increased inflammatory-related gene expression, but also accumulated excess cholesterol and lipid peroxidation in the liver tissues. In conclusion, our study demonstrated that feeding a fried oil-containing diet may trigger TGF-ß1-induced HSCs activation and thereby promote liver damage and fibrosis progression through enhancing the inflammatory response and lipid peroxidation.