Yangonin modulates lipid homeostasis, ameliorates cholestasis and cellular senescence in alcoholic liver disease via activating nuclear receptor FXR

Exploring bile acid transporters as key players in cancer development and treatment: Evidence from preclinical and clinical studies

Bile acid transporters (BATs) are integral membrane proteins belonging to various families, such as solute carriers, organic anion transporters, and ATP-binding cassette families. These transporters play a crucial role in bile acid transportation within the portal and systemic circulations, with expression observed in tissues, including the liver, kidney, and small intestine. Bile acids serve as signaling molecules facilitating the absorption and reabsorption of fats and lipids. Dysregulation of bile acid concentration has been implicated in tumorigenesis, yet the role of BATs in this process remains underexplored. Emerging evidence suggests that BATs may modulate various stages of cancer progression, including initiation, development, proliferation, metastasis, and tumor microenvironment regulation. Targeting BATs using siRNAs, miRNAs, and small compound inhibitors in preclinical models and their polymorphisms are well-studied for transporters like BSEP, MDR1, MRP2, OATP1A2, etc., and have shed light on their involvement in tumorigenesis, particularly in cancers such as those affecting the liver and gastrointestinal tract. While BATs' role in diseases like Alagille syndrome, biliary atresia, and cirrhosis have been extensively studied, their implications in cancer warrant further investigation. This review highlights the expression and function of BATs in cancer development and emphasizes the potential of targeting these transporters as a novel therapeutic strategy for various malignancies.

MetALD: Does it require a different therapeutic option?

New guidelines for the definitions of steatotic liver disease have named the entity of metabolic dysfunction and alcohol-associated liver disease (MetALD) as an overlap condition of metabolic dysfunction-associated steatotic liver disease (MASLD) and alcohol-associated liver disease. There is a broad range of therapeutics in all stages of development for MASLD, but these therapeutics, in general, have not been studied in patients with significant ongoing alcohol use. In this review, we discuss the current understanding of the endogenous and exogenous risks for MASLD and MetALD. Rational strategies for therapeutic intervention in MetALD include biopsychosocial interventions, alcohol use cessation strategies, including the use of medications for alcohol use disorder, and judicious use of therapeutics for steatotic liver disease. Therapeutics with promise for MetALD include incretin-based therapies, FGF21 agonists, thyroid hormone receptor beta agonists, sodium-glucose co-transporter 2 inhibitors, and agents to modify de novo lipogenesis. Currently, glucagon-like peptide 1 receptor agonists and peroxisome proliferator-activated receptor γ agonists have the largest body of literature supporting their use in MASLD, and there is a paucity of agents in trials for alcohol-associated liver disease. From existing studies, it is not clear if unique therapeutics or a combinatorial approach are needed for MetALD. Further elucidation of the safety and benefits of MASLD-related therapies is of paramount importance for advancing therapeutics for MetALD in carefully designed inclusive clinical trials.

Integrative analysis of non12-hydroxylated bile acid revealed the suppressed molecular map of alternative pathway in nonalcoholic steatohepatitis mice

Bile acids (BAs) are significantly altered in the liver and serum of patients with nonalcoholic steatohepatitis (NASH). However, the underlying mechanisms of these changes, particularly BA alternative pathways (BAP) responsible for non12-OH BAs, remain unclear. RNA-seq data were initially analyzed to reveal the changes of gene expression in NASH patients. Targeted metabolomics were conducted on plasma from NASH mice induced by high-fat or western diet with CCl4 for 10-24 weeks. Liver tissues were examined using proteomics, RT-qPCR, and western blotting. An integrated approach was then employed to analyze protein interactions and network correlations. Analysis of RNA-seq data revealed the inhibition of CYP7B1 in NASH patients, indicating the dysregulation of BAP. In NASH mouse models, dysregulation of BA circulation was observed by increased plasma total BA (TBA) levels and decreased liver TBA, with liver swelling and histopathological changes. Targeted metabolomics revealed suppressed levels of non12-OH BAs, which inversely correlated with increased liver injury markers. The reduced mRNA and protein expression of Fxr and upregulation of Lxr signaling in livers suggested the suppressed BAP was modulated by Fxr-Lxr signaling. Moreover, BAP interactions predominantly implicated multiple metabolism disruptions, involving 7 hub proteins (Hk1, Acadsb, Pklr, Insr, Ldlr, Cyp27a1, and Cyp7b1), offering promising therapeutic targets for NASH. We presented the metabolic and proteomic map of BAP and its regulatory network in NASH progression. Therapeutic targeting of BAP or its co-regulatory proteins holds promise for NASH treatment and metabolic syndrome management.

Aristolochic acid-induced dyslipidemia and hepatotoxicity: The potential role of FXR and AHR receptors

Aristolochic acids (AAs) represent a class of nitrophenanthrene carboxylic acids naturally existing or accidentally mixed in herbal medicines or crops, which have long been recognized for causing nephropathy. Recently, the linkage between AAs and liver injury has become a concern; however, the current understanding of the mechanism or mode of action (MOA) is limited. In the present study, we investigated nuclear receptor-mediated MOA associated with AAs-induced liver injury including dyslipidemia and hepatotoxicity. Bioinformatic analysis of AAI-interacting genes indicated nuclear receptor-mediated metabolizing pathways; Transcriptomic profiling of AAs-exposed rats with liver injury suggested FXR-, NRF2-, and AHR- mediated pathways in the injured livers of the rats. Mechanistic investigation using HepG2 cells indicated AAI-induced hepatic lipid accumulation by elevating Triglyceride (TG) through inhibition of the FXR. In addition, AAI-induced hepatocellular damage by activating the AHR pathway, which further generated ROS and activated the NRF2 pathway. Together, these results provided new clues for researchers who are interested in chemical-induced liver injury.

Bruceine A alleviates alcoholic liver disease by inhibiting AIM2 inflammasome activation via activating FXR

BACKGROUND

Alcoholic liver disease (ALD), a public health challenge worldwide caused by long-term persistent drinking, is life-threatening with minimal approved therapies. Hepatic steatosis accompanied by inflammation is an initial and inevitable stage in the complex progression of simple alcoholic liver injury to more severe liver diseases such as hepatitis, liver fibrosis, cirrhosis and liver cancer.

PURPOSE

We aimed to identify the therapeutic role of Bruceine A (BA) in ALD whilst attempting to explore whether its protective effects depend specifically on the farnesoid X receptor (FXR).

METHODS

Autodock was applied to detect the affinity between BA and FXR. Lieber-DeCarli liquid diet with 5 % ethanol (v/v) was adopted to establish the mouse ALD model. The lentivirus mediating FXR (LV-FXR) was injected into mice via the tail vein to establish FXR-overexpressed mice. FXR silencing or overexpression plasmids were transfected into AML-12 cells prior to ethanol stimulation. Quantitative real-time PCR, Western blotting and immunofluorescence assays were employed to determine the expression of related genes. We subjected liver sections to H&E and Oil Red O staining to evaluate the liver histological injury and the deposition of lipid droplets.

RESULTS

BA significantly reduced body weight and liver-to-body weight ratios as well as biochemical indexes in mice. Ethanol-induced liver damage and lipid accumulation could be alleviated by BA treatment. BA bound to FXR by two hydrogen bonds. There was a positive correlation between BA administration and FXR expression. BA inhibited the expression of lipid synthesis genes and enhanced the expression of lipid metabolism genes by activating FXR, thus alleviating steatosis in ALD. Moreover, BA exerted an ameliorative effect against inflammation by inhibiting the activation of absent in melanoma 2 (AIM2) inflammasome by activating FXR. FXR overexpression possessed the ability to counter the accumulation of lipid and the activation of AIM2 inflammasome caused by ethanol. FXR deficiency exacerbated ethanol-induced liver steatosis and inflammation. The hepatoprotective effect of BA could be disrupted by FXR antagonist guggulsterone (GS) in vivo and FXR siRNA in vitro.

CONCLUSION

BA alleviated alcoholic liver disease by inhibiting AIM2 inflammasome activation through an FXR-dependent mechanism. This study may potentially represent a new therapeutic approach for ALD.

Sarmentol H derived from Sedum sarmentosum Bunge directly targets FXR to mitigate cholestasis by recruiting SRC-1

BACKGROUND

Farnesoid X receptor (FXR) is a vital receptor for bile acids and plays an important role in the treatment of cholestatic liver disease. In addition to traditional bile acid-based steroidal agonists, synthetic alkaloids are the most commonly reported non-steroidal FXR agonists. Sarmentol H is a nor-sesquiterpenoid obtained from Sedum sarmentosum Bunge, and in vitro screening experiments have shown that it might be related to the regulation of the FXR pathway in a previous study.

PURPOSE

To investigate the therapeutic effects of sarmentol H on cholestasis and to determine whether sarmentol H directly targets FXR to mitigate cholestasis. Furthermore, this study aimed to explore the key amino acid residues involved in the binding of sarmentol H to FXR through site-directed mutagenesis.

METHODS

An intrahepatic cholestasis mouse model was established to investigate the therapeutic effects of sarmentol H on cholestasis. In vitro experiments, including Co-Ip and FXR-EcRE-Luc assays, were performed to assess whether sarmentol H activates FXR by recruiting the receptor coactivator SRC1. CETSA, SIP, DARTS, and ITC were used to determine the binding of sarmentol H to FXR protein. The key amino acid residues for sarmentol H binding to FXR were analyzed by molecular docking and site-directed mutagenesis. Finally, we conducted in vivo experiments on wild-type and Fxr-/- mice to further validate the anticholestatic target of sarmentol H.

RESULTS

Sarmentol H had significant ameliorative effects on the pathological conditions of cholestatic mice induced with ANIT. In vitro experiments suggested that it is capable of activating FXR and regulating downstream signaling pathways by recruiting SRC1. The target validation experiments showed that sarmentol H had the ability to bind to FXR as a ligand (KD = 2.55 μmol/L) and enhance the stability of its spatial structure. Moreover, site-directed mutagenesis revealed that THR292 and TYR365 were key binding sites for sarmentol H and FXR. Furthermore, knockout of the Fxr gene resulted in a significantly higher degree of ANIT-induced cholestatic liver injury than that in wild-type cholestatic mice, and the amelioration of cholestasis or regulatory effects on FXR downstream genes by sarmentol H also disappeared in Fxr-/- cholestatic mice.

CONCLUSION

Sarmentol H is an FXR agonist. This is the first study to show that it exerts a significant therapeutic effect on cholestatic mice, and can directly bind to FXR and activate it by recruiting the coactivator SRC1.

Emodin alleviates cholestatic liver injury by modulating Sirt1/Fxr signaling pathways

Emodin (EMO) has the effect of anti-cholestasis induced by alpha-naphthylisothiocyanate (ANIT). But its mechanism is still unclear. The farnesoid X receptor (Fxr) is the master bile acid nuclear receptor. Recent studies have reported that Sirtuin 1 (Sirt1) can regulate the activities of Fxr. The purpose of the current study was to investigate the mechanism of EMO against ANIT-induced liver injury based on Sirt1/Fxr signaling pathway. The ANIT-induced cholestatic rats were used with or without EMO treatment. Serum biochemical indicators, as well as liver histopathological changes were examined. The genes expressions of Sirt1, Fxr, Shp, Bsep and Mrp2 were detected. The expressions of Sirt1, Fxr and their downstream related genes were investigated in vitro. The results showed that EMO significantly alleviated ANIT-induced liver injury in rats, and increased Sirt1, Fxr, Shp, Bsep and Mrp2 gene expression in liver, while decreased the expression of Cyp7a1. EMO significantly activated Fxr, while Sirt1 inhibitor and Sirt1 gene silencing significantly reduced Fxr activity in vitro. Collectively, EMO in the right dose has a protective effect on liver injury induced by ANIT, and the mechanism may be through activation of Fxr by Sirt1, thus regulating bile acid metabolism, and reducing bile acid load in hepatocytes.

Role of FXR in the development of NAFLD and intervention strategies of small molecules

Non-alcoholic fatty liver disease (NAFLD) remains a prevailing etiological agent behind hepatocyte diseases like chronic liver disease. The spectrum of processes involved in NAFLD stages includes hepatic steatosis, non-alcoholic fatty liver, and non-alcoholic steatohepatitis (NASH). Without intervention, the progression of NASH can further deteriorate into cirrhosis and ultimately, hepatocellular carcinoma. The cardinal features that characterize NAFLD are insulin resistance, lipogenesis, oxidative stress and inflammation, extracellular matrix deposition and fibrosis. Due to its complex pathogenesis, existing pharmaceutical agents fail to take a curative or ameliorative effect on NAFLD. Consequently, it is imperative to identify novel therapeutic targets and strategies for NAFLD, ideally to improve the aforementioned key features in patients. As an enterohepatic regulator of bile acid homeostasis, lipid metabolism, and inflammation, FarnesoidX receptor (FXR) is an important pharmacological target for the treatment of NAFLD. Manipulating FXR to regulate lipid metabolic signaling pathways is a potential mechanism to mitigate NAFLD. Therefore, elucidating the modulatory character of FXR in regulating lipid metabolism in NAFLD has the potential to yield groundbreaking perspectives for drug design. This review details recent advances in the regulation of lipid depletion in hepatocytes and investigates the pivotal function of FXR in the progress of NAFLD.

Therapeutic effect of dietary ingredients on cellular senescence in animals and humans: A systematic review

BACKGROUND

Cellular senescence has been regarded as a therapeutic target for ageing and age-related diseases. Several senotherapeutic agents have been proposed, including compounds derived from natural products which hold the translational potential to promote healthy ageing. This systematic review examined the association of dietary ingredients with cellular senescence in animals and humans, with an intent to identify dietary ingredients with senotherapeutic potential.

METHODS

This systematic review was registered at PROSPERO International prospective register of systematic reviews (Reg #: CRD42022338885). The databases PubMed and Embase were systematically searched for key terms related to cellular senescence, senescence markers, diets, nutrients and bioactive compounds. Intervention and observational studies on human and animals investigating the effects of dietary ingredients via oral administration on cellular senescence load were included. The SYRCLE's risk of bias tool and Cochrane risk of bias tool v2.0 were used to assess the risk of bias for animal and human studies respectively.

RESULTS

Out of 5707 identified articles, 83 articles consisting of 78 animal studies and 5 human studies aimed to reduce cellular senescence load using dietary ingredients. In animal studies, the most-frequently used senescence model was normative ageing (26 studies), followed by D-galactose-induced models (17 studies). Resveratrol (8 studies), vitamin E (4 studies) and soy protein isolate (3 studies) showed positive effects on reducing the level of senescence markers such as p53, p21, p16 and senescence-associated ß-galactosidase in various tissues of physiological systems. In three out of five human studies, ginsenoside Rg1 had no positive effect on reducing senescence in muscle tissues after exercise. The risk of bias for both animal and human studies was largely unclear.

CONCLUSION

Resveratrol, vitamin E and soy protein isolate are promising senotherapeutics studied in animal models. Studies testing dietary ingredients with senotherapeutic potential in humans are limited and translation is highly warranted.

The zhuyu pill relieves rat cholestasis by regulating the mRNA expression of lipid and bile metabolism associated genes

Background: The Zhuyu pill (ZYP), composed of Coptis chinensis Franch. and Tetradium ruticarpum (A. Jussieu) T. G. Hartley, is an effective traditional Chinese medicine with potential anti-cholestatic effects. However, the underlying mechanisms of ZYP remain unknown. Objective: To investigate the mechanism underlying the interventional effect of ZYP on mRNA-seq analysis in cholestasis rat models. Materials and methods: This study tested the effects of a low-dose (0.6 g/kg) and high-dose (1.2 g/kg) of ZYP on a cholestasis rat model induced by α-naphthyl-isothiocyanate (ANIT, 50 mg/kg). Serum biochemistry and histopathology results were used to evaluate the therapeutic effect of ZYP, and mRNA-Seq analysis was performed and verified using real-time fluorescence quantitative PCR (qRT-PCR). GO, KEGG, and GSEA analyses were integrated to identify the mechanism by which ZYP impacted cholestatic rats. Results: ZYP was shown to significantly improve abnormal changes in the biochemical blood indexes and liver histopathology of cholestasis rats and regulate pathways related to bile and lipid metabolism, including fatty acid metabolism, retinol metabolism, and steroid hormone biosynthesis, to alleviate inflammation, cholestasis, and lipid metabolism disorders. Relative expression of the essential genes Cyp2a1, Ephx2, Acox2, Cyp1a2, Cyp2c11, and Sult2a1 was verified by qRT-PCR and showed the same trend as mRNA-seq analysis. Conclusion: ZYP has a significant anti-cholestatic effect by regulating bile metabolism and lipid metabolism related pathways. These findings indicate that ZYP is a novel and promising prospect for treating cholestasis.

Environmental endocrine disruptors and pregnane X receptor action: A review

The pregnane X receptor (PXR) is a kind of orphan nuclear receptor activated by a series of ligands. Environmental endocrine disruptors (EEDs) are a wide class of molecules present in the environment that are suspected to have adverse effects on the endocrine system by interfering with the synthesis, transport, degradation, or action of endogenous hormones. Since EEDs may modulate human/rodent PXR, this review aims to summarize EEDs as PXR modulators, including agonists and antagonists. The modular structure of PXR is also described, interestingly, the pharmacology of PXR have been confirmed to vary among different species. Furthermore, PXR play a key role in the regulation of endocrine function. Endocrine disruption of EEDs via PXR and its related pathways are systematically summarized. In brief, this review may provide a way to understand the roles of EEDs in interaction with the nuclear receptors (such as PXR) and the related pathways.

Cellular senescence in liver diseases: From mechanisms to therapies

Cellular senescence is an irreversible state of cell cycle arrest, characterized by a gradual decline in cell proliferation, differentiation, and biological functions. Cellular senescence is double-edged for that it can provoke organ repair and regeneration in physiological conditions but contribute to organ and tissue dysfunction and prime multiple chronic diseases in pathological conditions. The liver has a strong regenerative capacity, where cellular senescence and regeneration are closely involved. Herein, this review firstly introduces the morphological manifestations of senescent cells, the major regulators (p53, p21, and p16), and the core pathophysiologic mechanisms underlying senescence process, and then specifically generalizes the role and interventions of cellular senescence in multiple liver diseases, including alcoholic liver disease, nonalcoholic fatty liver disease, liver fibrosis, and hepatocellular carcinoma. In conclusion, this review focuses on interpreting the importance of cellular senescence in liver diseases and summarizes potential senescence-related regulatory targets, aiming to provide new insights for further researches on cellular senescence regulation and therapeutic developments for liver diseases.

A review of edible plant-derived natural compounds for the therapy of liver fibrosis

Liver fibrosis has a high incidence worldwide and is the common pathological basis of many chronic liver diseases. Liver fibrosis is caused by the excessive deposition of extracellular matrix and concomitant collagen accumulation in livers and can lead to the development of liver cirrhosis and even liver cancer. A large number of studies have provided evidence that liver fibrosis can be blocked or even reversed by appropriate medical interventions. However, the antifibrosis drugs with ideal clinical efficacy are still insufficient. The edible plant-derived natural compounds have been reported to exert effective antifibrotic effects with few side-effects, representing a kind of promising source for the treatment of liver fibrosis. In this article, we reviewed the current progress of the natural compounds derived from dietary plants in the treatment of liver fibrosis, including phenolic compounds (capsaicin, chlorogenic acid, curcumin, ellagic acid, epigallocatechin-3-gallate, resveratrol, sinapic acid, syringic acid, vanillic acid and vitamin E), flavonoid compounds (genistein, hesperidin, hesperetin, naringenin, naringin and quercetin), sulfur-containing compounds (S-allylcysteine, ergothioneine, lipoic acid and sulforaphane) and other compounds (betaine, caffeine, cucurbitacin B, lycopene, α-mangostin, γ-mangostin, ursolic acid, vitamin C and yangonin). The pharmacological effects and related mechanisms of these compounds in in-vivo and in-vitro models of liver fibrosis are focused.

Mechanism of crocin I on ANIT-induced intrahepatic cholestasis by combined metabolomics and transcriptomics

Background: Intrahepatic cholestasis (IC) is a disorder of bile production, secretion, and excretion with various causes. Crocin I (CR) is effective in the treatment of IC, but its underlying mechanisms need to be further explored. We aimed to reveal the therapeutic mechanism of crocin I for IC by combining an integrated strategy of metabolomics and transcriptomics. Methods: The hepatoprotective effect of CR against cholestasis liver injury induced by α-naphthylisothiocyanate (ANIT) was evaluated in rats. The serum biochemical indices, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bile acid (TBA), total bilirubin (TBIL), direct bilirubin (DBIL), tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), and interleukin 1β (IL-1β), as well as the liver oxidative stress indexes and the pathological characteristics of the liver were analyzed. In addition, we also performed a serum metabolomics study using UPLC-Q Exactive HF-X technology to investigate the effect of CR on the serum of rats with ANIT-induced IC and screened potential biomarkers. The enrichment analysis of differential expressed genes (DEGs) was performed by transcriptomics. Finally, the regulatory targets of CR on potential biomarkers were obtained by combined analysis, and the relevant key targets were verified by western blotting. Results: CR improved serum and liver homogenate indexes and alleviated liver histological injury. Compared with ANIT group, the CR group had 76 differential metabolites, and 10 metabolic pathways were enriched. There were 473 DEGs significantly changed after CR treatment, most of which were enriched in the retinol metabolism, calcium signaling pathway, PPAR signaling pathway, circadian rhythm, chemokine signaling pathway, arachidonic acid metabolism, bile secretion, primary bile acid biosynthesis, and other pathways. By constructing the "compound-reaction-enzyme-gene" interaction network, three potential key-target regulation biomarkers were obtained, including 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR), ATP-binding cassette transporter G5 (ABCG5), and sulfotransferase2A1(SULT2A1), which were further verified by western blotting. Compared with the ANIT group, the CR group significantly increased the expression of ABCG5 and SULT2A1, and the expression of HMGCR significantly decreased. Conclusion: Combined metabolomic and transcriptomic analyses show that CR has a therapeutic effect on IC through regulation of the biosynthesis of bile acids and bilirubin in the bile secretion pathway and regulation of the expression of HMGCR, ABCG5, and SULT2A1.

Ginsenoside Rc Modulates SIRT6-NRF2 Interaction to Alleviate Alcoholic Liver Disease

Alcoholic liver disease (ALD) is a serious worldwide health problem. Ginsenoside Rc is a major active ingredient isolated from Panax ginseng, whose pharmacological effects counteract oxidative stress, inflammation, and lipid accumulation. However, it is still unclear whether ginsenoside Rc might exert beneficial effects on alcohol-induced liver injury. To this aim, mice primary hepatocytes (MPHs) were challenged with alcohol to test ginsenoside Rc's effects on their intracellular alcohol metabolism. C57BL/6J mice or SIRT6alb-/- mice were chronically fed a diet with added alcohol or given a single gavage of alcohol with or without ginsenoside Rc. Analyses of alcohol metabolism, oxidative stress, inflammation, lipid metabolism, and RNaseq expression were conducted to explore potential targets exploited by ginsenoside Rc to protect against ALD. Our results showed that ginsenoside Rc attenuated alcohol-induced liver injury by regulating oxidative stress, inflammation, and lipid accumulation both in vivo and in vitro. Ginsenoside Rc did increase the deacetylase activity of SIRT6, thereby lowering acetylated NRF2 levels, which elevated NRF2's stability, and subsequently exerting an antioxidant effect. In keeping with this, the hepatic knockout of SIRT6 almost abolished the hepatoprotective effects of ginsenoside Rc against ALD. Therefore, our results suggest that ginsenoside Rc attenuated hepatocytes' damage and oxidative stress in ALD by up-regulating the SIRT6/NRF2 pathway. Hence, ginsenoside Rc may be a promising drug to treat or relieve ALD.

Long-term oral administration of Epimedii Folium induced cholestasis in mice by interfering with bile acid transport

ETHNOPHARMACOLOGICAL RELEVANCE

Epimedii Folium (EF) is a common traditional Chinese medicine that functions as a tonifying kidney yang to strengthen bones and muscles and dispel wind dampness (limb pain, lethargy, nausea, anorexia, and loose stools). Several studies have reported the potential risk of cholestatic liver damage from EF use; however, there have been few investigations of EF-induced cholestasis, particularly the underlying mechanisms.

AIMS OF THE STUDY

The purpose of this study was to evaluate the risk of EF-induced cholestasis in vivo and to explore the mechanisms of action.

MATERIALS AND METHODS

ICR mice were orally administered a water extract of EF (WEF) in doses of 6.5 and 19.5 g/kg/day for 14 weeks. Liver-to-body weight ratios, body weight, histopathological examination, and biochemical analyses were performed to assess WEF-induced cholestasis in the mice. Genes associated with bile acid (BA) metabolism and transport, including sodium taurocholate cotransporting polypeptide (NTCP), cytochrome P450 8B1 (CYP8B1), bile-salt export pump (BSEP), multidrug resistance P-glycoproteins 1 (MDR1), and farnesoid X receptor (FXR), were measured at the transcript and protein levels to investigate the potential mechanisms through which cholestasis is aroused by EF.

RESULTS

After administration of WEF for 14 weeks, mice in the high-dose WEF group showed poor health with an increased liver-to-body weight ratio as well as higher serum aminotransferase, alkaline phosphatase, direct bilirubin, and total BA levels. Compared with the control group, mRNA expression of NTCP and cholesterol 7a-hydroxylase (CYP7A1) increased, and levels of BSEP, MDR1, multidrug resistance-associated protein 2, and multidrug resistance-associated protein 3 decreased in the WEF-treated group. NTCP, BSEP, MDR1, and CYP8B1 showed similar mRNA and protein expression trends.

CONCLUSION

We demonstrated that the long-term oral administration of WEF causes cholestatic liver injury in mice, which is consistent with reported clinical cases. Furthermore, we found that the destruction of BA metabolism and transport is involved in WEF-induced cholestasis. The fine-scale molecular mechanisms of WEF-induced cholestasis and the active compounds of EF need further study.

Curcumol Suppresses CCF-Mediated Hepatocyte Senescence Through Blocking LC3B–Lamin B1 Interaction in Alcoholic Fatty Liver Disease

Recent studies indicated that hepatocyte senescence plays an important role in the development of alcoholic fatty liver disease (AFLD), suggesting that inhibition of hepatocyte senescence might be a potential strategy for AFLD treatment. The present study investigated the effect of curcumol, a component from the root of Rhizoma Curcumae, on hepatocyte senescence in AFLD and the underlying mechanisms implicated. The results showed that curcumol was able to reduce lipid deposition and injury in livers of ethanol liquid diet-fed mice and in ethanol-treated LO2 cells. Both in vivo and in vitro studies indicated that supplementation with curcumol effectively alleviated ethanol-induced cellular senescence as manifested by a decrease in senescence-associated β-galactosidase (SA-β-gal) activity, a downregulated expression of senescence-related markers p16 and p21, and dysfunction of the telomere and telomerase system. Consistently, treatment with curcumol led to a marked suppression of ethanol-induced formation of cytoplasmic chromatin fragments (CCF) and subsequent activation of cGAS-STING, resulting in a significant reduction in senescence-associated secretory phenotype (SASP)-related inflammatory factors’ secretion. Further studies indicated that curcumol’s inhibition of CCF formation might be derived from blocking the interaction of LC3B with lamin B1 and maintaining nuclear membrane integrity. Taken together, these results indicated that curcumol was capable of ameliorating AFLD through inhibition of hepatocyte senescence, which might be attributed to its blocking of LC3B and lamin B1 interaction and subsequent inactivation of the CCF-cGAS-STING pathway. These findings suggest a promising use of curcumol in the treatment of AFLD.

Comparison of bile acids profiles in the enterohepatic circulation system of mice and rats

Bile acids (BAs) were selected as biomarkers for the diagnosis and prevention of multiple liver diseases, and they were also considered as an important signal transductor via "liver-gut" axis. As important factors for maintaining the normal function and tissue morphology, BA homeostasis throughout the enterohepatic circulation system was guaranteed by BA synthases and transporters, nuclear receptors (NRs) and gut microbiota, all of which presented significant species differences. Thus, we simultaneously quantify BA profiles in the enterohepatic circulation of SD rats and C57BL/6 mice to reveal the species differences of BA homeostasis between these two main rodents of preclinical studies. Our results showed that BA profiles of mice plasma, bile and liver were most dissimilar from these of rats. Meanwhile, BAs profiles also presented obvious species differences in the intestine of mice and rats, especially small intestine. Unlike rats, taurine-conjugated bile acids (T-BAs) were predominant in mice small intestine content and tissue, in which taurocholic acid (TCA) was the most prominent BAs. BAs dynamic analysis showed that compared with rats, mice showed stranger taurine and glycine de-conjugations in lager intestine. However, both the ratios of unconjugated bile acids (Un-BAs) to conjugated BAs, and secondary BAs to primary BAs in mice small content and tissue were all much lower than these in rats. Furthermore, ileum BAs profiles also showed significantly separation trend between rats and mice, whether content or tissue. Our data revealed that the patterns of BAs homeostasis in mice enterohepatic circulation system were significantly different from these in rats (especially in intestine), suggesting that more cautious should be paid to the selection of BAs as biomarkers for disease diagnosis or/and drug induced toxicity, and the certain role and mechanism of individual BA in the pathological process of BA-related diseases via "liver-gut" axis should be verified by using of multiple species.

Farnesoid X receptor (FXR) agonists induce hepatocellular apoptosis and impair hepatic functions via FXR/SHP pathway

Farnesoid X receptor (FXR) plays an indispensable role in liver homeostasis and has been a promising drug target for hepatic diseases. However, the concerns of undesired biological actions limit the clinical applications of FXR agonists. To reveal the intrinsic mechanism of FXR agonist-induce hepatotoxicity, two typical FXR agonists with different structures (obeticholic acid (OCA) and Px-102) were investigated in the present study. By detecting MMP, ROS, and ATP and analyzing the fate of cells, we found that both OCA and Px-102 reduced the mitochondrial function of hepatocytes and promoted cell apoptosis. Gene ablation or inhibition of FXR or SHP ameliorated the cytotoxicities of OCA and Px-102, which indicated the adverse actions of FXR/SHP activation including down-regulation of phosphorylation of PI3K/AKT and functional hepatic genes. The dose-related injurious effects of OCA (10 mg/kg and 30 mg/kg) and Px-102 (5 mg/kg and 15 mg/kg) on the liver were confirmed on a high-fat diet mouse model. The decrease of hepatocyte-specific genes and augmenter of liver regeneration in the liver caused by OCA or Px-102 suggested an imbalance of liver regeneration and a disruption of hepatic functions. Exploration of intestinally biased FXR agonists or combination of FXR agonist with apoptosis inhibitor may be more beneficial strategies for liver diseases.

Cultured bear bile powder ameliorates acute liver injury in cholestatic mice via inhibition of hepatic inflammation and apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Natural bear bile powder (NBBP) is a traditional Chinese medicine used for treating liver dysfunction. Cultured bear bile powder (CBBP), which is produced using biotransformation of chicken bile, acts as an appropriate substitute for NBBP when treating cholestatic liver injury.

AIM OF THE STUDY

To investigate the molecular mechanisms underlying the hepatoprotective effects of CBBP in an α-naphthylisothiocyanate (ANIT)-induced cholestatic mouse model.

MATERIALS AND METHODS

Cholestatic mice were pretreated with CBBP or NBBP via oral gavage once a day for two weeks. Their blood biochemistry and liver histopathology were then evaluated using standard protocols. Western blot analyses, real-time polymerase chain reaction, and immunohistochemistry were used to evaluate changes in the protein levels and gene expression profiles of factors associated with hepatic inflammation and apoptosis in cholestatic mice.

RESULTS

CBBP significantly decreased the serum indices of liver injury, and ameliorated neutrophil infiltration and hepatocyte necrosis within liver tissue of cholestatic mice. Expression of the inflammatory factors, such as tumor necrosis factor-α, interleukin-1β (IL-1β), IL-6, monocyte chemoattractant protein-1, and intercellular adhesion molecule 1, was significantly reduced in CBBP-treated cholestatic mice. Moreover, proteins involved in the toll-like receptor 4/myeloid differentiation factor 88/nuclear factor-kappa B (TLR4/Myd88/NF-κB) signaling pathway, such as CD14, TLR4, Myd88, and NF-κB, that were increased in cholestatic mice, were downregulated by CBBP. Meanwhile, increased expression of the apoptosis-related proteins, caspase-3 and Bax, in cholestatic mice was reversed by CBBP treatment.

CONCLUSION

CBBP treatment alleviates ANIT-induced cholestasis and liver injury by reducing hepatocyte inflammation and apoptosis.