Advances of natural activators for Nrf2 signaling pathway on cholestatic liver injury protection: a review

Activation of Nrf2/HO-1 signaling pathway exacerbates cholestatic liver injury

Nuclear factor erythroid 2-related factor-2 (Nrf2) antioxidant signaling is involved in liver protection, but this generalization overlooks conflicting studies indicating that Nrf2 effects are not necessarily hepatoprotective. The role of Nrf2/heme oxygenase-1 (HO-1) in cholestatic liver injury (CLI) remains poorly defined. Here, we report that Nrf2/HO-1 activation exacerbates liver injury rather than exerting a protective effect in CLI. Inhibiting HO-1 or ameliorating bilirubin transport alleviates liver injury in CLI models. Nrf2 knockout confers hepatoprotection in CLI mice, whereas in non-CLI mice, Nrf2 knockout aggravates liver damage. In the CLI setting, oxidative stress activates Nrf2/HO-1, leads to bilirubin accumulation, and impairs mitochondrial function. High levels of bilirubin reciprocally upregulate the activation of Nrf2 and HO-1, while antioxidant and mitochondrial-targeted SOD2 overexpression attenuate bilirubin toxicity. The expression of Nrf2 and HO-1 is elevated in serum of patients with CLI. These results reveal an unrecognized function of Nrf2 signaling in exacerbating liver injury in cholestatic disease.

The beneficial health effects of puerarin in the treatment of cardiovascular diseases: from mechanisms to therapeutics

Cardiovascular diseases (CVDs) are the leading causes of death globally that seriously threaten human health. Although novel western medicines have continued to be discovered over the past few decades to inhibit the progression of CVDs, new drug research and development for treating CVDs with less side effects and adverse reactions are continuously being desired. Puerarin is a natural product found in a variety of medicinal plants belonging to the flavonoid family with potent biological and pharmacological activities. Abundant research findings in the literature have suggested that puerarin possesses a promising prospect in treating CVDs. In recent years, numerous new molecular mechanisms of puerarin have been explored in experimental and clinical studies, providing new evidence for this plant metabolite to protect against CVDs. This article systematically introduces the history of use, bioavailability, and various dosage forms of puerarin and further summarizes recently published data on the major research advances and their underlying therapeutic mechanisms in treating CVDs. It may provide references for researchers in the fields of pharmacology, natural products, and internal medicine.

Design, synthesis, and anti-tumor activity of derivatives of ring A and C-28 of asiatic acid

Based on computer-aided drug design (CADD), the active groups of the known active small molecule compounds that can bind to EGFR target protein were analyzed through the molecular docking method. Then, 12 novel asiatic acid derivatives were synthesized by introducing active groups at ring A and C-28 positions of asiatic acid. The structures of these novel compounds were determined by NMR and MS. Furthermore, the anti-tumor activities of these derivatives on human lung cancer cells (A549) and human breast cancer cells (MCF-7) were evaluated by MTT assay. In conclusion, compounds I4 and II3 have stronger anti-cancer activity than parent compounds, the activities were stronger than gefitinib and comparable to afatinib, which may be potential candidate compounds for tumor therapy.

From inflammation to pyroptosis: Understanding the consequences of cadmium exposure in chicken liver cells

Hepatotoxicity is frequently observed following acute cadmium (Cd) exposure in chicken. Oxidative stress and subsequent inflammation are regarded as the main reasons for cadmium-induced liver injury. NOD-like receptor (NLR) family pyrin domain-containing 3 (NLRP3) inflammasome-induced pyroptosis is involved in various inflammatory diseases, including liver injury. Poultry are more susceptible to harmful effects of heavy metals. However, the mechanism of cadmium-induced liver injury in chicken is still elusive. In this study, the effect of cadmium on chicken liver cells and the underlying mechanisms were investigated. The results showed mitochondria was damaged and excessive reactive oxygen species (ROS) were generated in chicken liver cell line LMH after cadmium exposure. Furthermore, cadmium-induced NLRP3 inflammasome activation and the cell membrane rupture indicated LMH cells pyroptosis. The ROS scavengers, acetylcysteine (NAC) and Mito-TEMPO prevented pyroptosis in LMH cells, suggesting that ROS were responsible for the activation of the NLRP3 inflammasome induced by cadmium. Additionally, anti-oxidative transcription factor Nrf2 was inhibited after cadmium exposure, explaining the excessive ROS generation. In summary, our study showed that cadmium leads to ROS generation by inducing mitochondrial damage and inhibiting Nrf2 activity, which promotes NLRP3 inflammasome activation and eventually induces pyroptosis in LMH cells.

Therapeutic approaches for cholestatic liver diseases: the role of nitric oxide pathway

Cholestasis describes bile secretion or flow impairment, which is clinically manifested with fatigue, pruritus, and jaundice. Neutrophils play a crucial role in many diseases such as cholestasis liver diseases through mediating several oxidative and inflammatory pathways. Data have been collected from clinical, in vitro, and in vivo studies published between 2000 and December 2021 in English and obtained from the PubMed, Google Scholar, Scopus, and Cochrane libraries. Although nitric oxide plays an important role in the pathogenesis of cholestatic liver diseases, excessive levels of NO in serum and affected tissues, mainly synthesized by the inducible nitric oxide synthase (iNOS) enzyme, can exacerbate inflammation. NO induces the inflammatory and oxidative processes, which finally leads to cell damage. We found that natural products such as baicalin, curcumin, resveratrol, and lycopene, as well as chemical likes ursodeoxycholic acid, dexamethasone, rosuvastatin, melatonin, and sildenafil, are able to markedly attenuate the NO production and iNOS expression, mainly through inducing the nuclear factor κB (NF-κB), Janus kinase and signal transducer and activator of transcription (JAK/STAT), and toll like receptor-4 (TLR4) signaling pathways. This study summarizes the latest scientific data about the bile acid signaling pathway, the neutrophil chemotaxis recruitment process during cholestasis, and the role of NO in cholestasis liver diseases. Literature review directed us to propose that suppression of NO and its related pathways could be a therapeutic option for preventing or treating cholestatic liver diseases.

Isobavachalcone attenuates liver fibrosis via activation of the Nrf2/HO-1 pathway in rats

Liver fibrosis, a progression of chronic liver disease, is a significant concern worldwide due to the lack of effective treatment modalities. Recent studies have shown that natural products play a crucial role in preventing and treating liver fibrosis. Isobavachalcone (IBC) is a chalcone compound with anti-inflammatory, antioxidant, and anti-cancer properties. However, its potential antifibrotic effects remain to be elucidated. This study aimed to investigate the antifibrotic effects of IBC on liver fibrosis and its underlying mechanisms in rats. The results showed that IBC significantly ameliorated the pathological damage and collagen deposition in liver tissues; it also reduced the levels of hydroxyproline (HYP), alanine aminotransferase (ALT), and aspartate aminotransferase (AST). In addition, IBC activated Nuclear factor E2-associated factor 2/Hemeoxygenase-1 (Nrf2/HO-1) signaling, leading to the nuclear translocation of Nrf2. This translocation subsequently increased the levels of superoxide dismutase (SOD) and glutathione (GSH) and decreased the levels of malondialdehyde (MDA) and reactive oxygen species (ROS), thereby alleviating oxidative stress-induced damage. Moreover, it inhibited the expression of nuclear factor kappa B (NF-κB), which further reduced the levels of downstream inflammatory factors, such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and IL-1 beta (IL-1β), thereby suppressing the activation of HSCs and weakening liver fibrosis. In HSC-T6 cell experiments, changes observed in inflammatory responses, oxidative stress indicators, and protein expression were consistent with the in vivo results. Furthermore, the Nrf2 inhibitor (ML385) attenuated the effect of IBC on inhibiting the activation of quiescent HSCs. Consequently, IBC could alleviate liver fibrosis by activating Nrf2/ HO-1 signaling.

Ginsenoside Rg1 alleviates ANIT-induced cholestatic liver injury by inhibiting hepatic inflammation and oxidative stress via SIRT1 activation

ETHNOPHARMACOLOGICAL RELEVANCE

Ginseng (Panax ginseng C. A. Mey) is a common traditional Chinese medicine used for anti-inflammation, treating colitis, type 2 diabetes, diarrhea, and recovering hepatobiliary function. Ginsenosides, the main active components isolated from ginseng, possess liver and gallbladder diseases therapeutic potential.

AIMS OF THE STUDY

Cholestatic liver injury (CLI) is a liver disease induced by intrahepatic accumulation of toxic bile acids and currently lacks clinically effective drugs. Our previous study found that ginsenosides alleviated CLI by activating sirtuin 1 (SIRT1), but the effective ingredients and the underlying mechanism have not been clarified. This study aimed to identify an effective ingredient with the most significant activation effect on SIRT1 from the five major monomer saponins of ginsenosides: Rb1, Rd, Rg1, 20s-Rg3, and Rc further explore its protective effects on CLI, and elaborate its underlying mechanism.

MATERIALS AND METHODS

Discovery Studio 3.0 was used to conduct molecular docking between monomer saponins and SIRT1, and further detect the influence of monomer saponins on SIRT1 activity in vitro. Finally, it was determined that Rg1 had the most significant stimulative effect on SIRT1, and the hepatoprotective activity of Rg1 in CLI was explored in vivo. Wild-type mice were intragastrically α-naphthylisothiocyanate (ANIT) to establish an experimental model of intrahepatic cholestasis and Rg1 intervention, and then liver injury and cholestasis related indexes were detected. In addition, Liver-specific SIRT1 gene knockout (SIRT1-/-) mice were administered with ANIT and/or Rg1 to further investigate the mechanism of action of Rg1.

RESULTS

The results of molecular docking and in vitro experiments showed that all the five ginsenoside monomers could bind to the active site of SIRT1 and promote SIRT1 activity in HepG2 cells. Among them, Rg1 exhibited the most significant stimulation of SIRT1 activity in cholestasis. Besides, it could ameliorate ANIT-induced inflammation and oxidative stress in HepG2 cells. Therefore, we investigated the hepatoprotective effect and mechanism of Rg1 on CLI. Results showed that Rg1 reversed the ANIT-induced increase in biochemical parameters, improved liver pathological injury, and decreased liver lipid accumulation, reactive oxygen species and pro-inflammatory factor levels. Mechanistically, Rg1 induced SIRT1 expression, followed by promoted the activity of Nrf2 and suppressed the activation of NF-κB. Interestingly, the hepatoprotective effect of Rg1 was blocked in SIRT1-/- mice.

CONCLUSION

Rg1 mitigated ANIT-induced CLI via upregulating SIRT1 expression, and our results suggested that Rg1 is a candidate compound for treating CLI.

Papaverine attenuates the progression of alpha naphthylisothiocyanate induce cholestasis in rats

Cholestasis is a hepatobiliary condition that manifests as acute or chronic and results from disruptions in the bile flow, formation, or secretion processes. The Farnesoid X receptor (FXR) is a vital target for the therapy of cholestasis since it regulates BA homeostasis. Despite the discovery of multiple active FXR agonists, there are still no effective treatments for cholestasis. Papaverine is identified as an FXR agonist.This study investigates papaverine's efficacy and probable mechanism in protecting against alpha naphthylisothiocyanate (ANIT) induced cholestasis. Thirty male albino rats were divided into three groups, each with ten rats. Group I (control) rats were administered 1 mL/kg corn oil 48 h before sacrifice; group II rats were orally administered 100 mg/kg ANIT. Group III received a 200 mg/kg dosage of papaverine over seven consecutive days. A single dose of ANIT at a concentration of 100 mg/kg was orally administered on the fifth day; group II and III animals were euthanized 48 h after inducing cholestasis, and serum concentrations of liver function tests and total bile acid (TBA) were measured. Besides measuring the inflammatory mediator's tumor necrosis factor-alpha (TNF-α) and interleukin 1 (IL-1β), antioxidant markers such as superoxide dismutase (SOD) and glutathione (GSH) were also assessed. The findings indicated the enhancement in the liver function test and total bile acids, as well as in liver histology; papaverine significantly lowered TNF-α and IL-1β while SOD and GSH significantly increased. Additionally, papaverine upregulates Fxr gene expression, bile salt export pump (Besp), small heterodimer partner (shp), hepatocyte nuclear factor 1α (Hnfα), nuclear factor erythroid 2-related factor (Nrf2), heme oxygenase (Ho-1), NAD(P)H quinone oxidoreductase 1 (Nqo1). Furthermore, papaverine increased protein expressions of Sirtuin1. (SIRT 1), FXR, HO-1, and BSEP levels in the rats' livers. The protective effects of papaverine may be attributed to the activation of FXR signaling pathways. These findings revealed that papaverine protects against ANIT-induced Cholestasis.

Wedelolactone alleviates cholestatic liver injury by regulating FXR-bile acid-NF-κB/NRF2 axis to reduce bile acid accumulation and its subsequent inflammation and oxidative stress

BACKGROUND

Cholestatic liver diseases (CLD) comprise a variety of disorders of bile formation, which causes chronic exposure to bile acid (BA) in the liver generally and results in hepatotoxicity and progressive hepatobiliary injury. Wedelolactone (7-methoxy-5, 11, 12-trihydroxy-coumestan, WED), the natural active compound derived from Ecliptae Herba, has been reported with valuable bioactivity for liver protection. Nevertheless, the effect of WED on cholestatic liver injury (CLI) remains unexplored.

PURPOSE

The present study aims to elucidate the protective effect of WED on Alpha-naphthylisothiocyanate (ANIT)-induced CLI mice, and to investigate its potential pharmacological mechanism.

METHODS

The anit-cholestatic and hepatoprotective effects of WED were evaluated in ANIT-induced CLI mice. Non-targeted metabolomics study combined with ingenuity pathway analysis (IPA) was used to explore the key mechanism of WED. The BA metabolic profile in enterohepatic circulation was analyzed to evaluate the effect of WED in regulating BA metabolism. Furthermore, molecular dynamics (MD) simulation and cellular thermal shift assay (CETSA) were used to simulate and verify the targeting activation of WED on the Farnesoid X receptor (FXR). The core role of FXR in WED promoting BA transportation, and alleviating BA accumulation-induced hepatotoxicity was further evaluated in WT and FXR knockout mice or hepatocytes.

RESULTS

WED dose-dependently alleviated ANIT-induced cholestasis and liver injury in mice, and simultaneously suppressed the signaling pathway of nuclear factor-kappa B/nuclear factor-erythroid 2-related factor 2 (NF-κB/NRF2) to relieve inflammation and oxidative stress. At the metabolite level, WED improved the metabolic disorder in CLI mice focusing on the metabolism of BA, arachidonic acid, and glycerophospholipid, that closely related to the process of BA regulation, inflammation, and oxidative damage. WED targeting activated FXR, which then transcribed its target genes, including the bile salt export pump (BSEP) and the BA transporter, and subsequently increased BA transportation to restore the damaged enterohepatic circulation of BA. Meanwhile, WED alleviated hepatic BA accumulation and protected the liver from BA-induced damage via NF-κB/NRF2 signaling pathway. Furthermore, FXR deficiency suppressed the protective effect of WED in vitro and in vivo.

CONCLUSION

WED regulated BA metabolism and alleviated hepatic damage in cholestasis. It protected the liver according to adjusted BA transportation and relieved BA accumulation-related hepatotoxicity via FXR-bile acid-NF-κB/NRF2 axis. Our study provides novel insights that WED might be a promising strategy for cholestatic liver disease.

The protective effect of forsythiaside A on 3,5-diethoxycarbonyl-1,4-dihydrocollidine-induced cholestatic liver injury in mice: Based on targeted metabolomics and molecular biology technology

Cholestasis is a disorder of bile secretion and excretion caused by a variety of etiologies. At present, there is a lack of functional foods or drugs that can be used for intervention. Forsythiaside A (FTA) is a natural phytochemical component isolated from the medicinal plant Forsythia suspensa (Thunb.) Vahl, which has a significant hepatoprotective effect. In this study, we investigated whether FTA could alleviate liver injury induced by cholestasis. In vitro, FTA reversed the decrease in viability of human intrahepatic bile duct epithelial cells, the decrease in antioxidant enzymes (SOD1, CAT and GSH-Px), and cell apoptosis induced by lithocholic acid. In vivo, FTA protected mice from 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-induced liver injury, abnormal serum biochemical indexes, abnormal bile duct hyperplasia, and inflammatory infiltration. Furthermore, FTA treatment alleviated liver fibrosis by inhibiting collagen deposition and HSC activation. The metabonomic results showed that DDC-induced bile acid disorders in the liver and serum were reversed after FTA treatment, which may benefit from the activation of the FXR/BSEP axis. In addition, FTA treatment increased the levels of antioxidant enzymes in the serum and liver. Meanwhile, FTA treatment inhibited ROS and MDA levels and cleaved caspase 3 protein expression, thereby reducing DDC-induced hepatic oxidative stress and apoptosis. Further studies showed that the antioxidant effects of FTA were dependent on the activation of the BRG1/NRF2/HO-1 axis. In a word, FTA has a significant hepatoprotective effect on cholestatic liver injury, and can be further developed as a functional food or drug to prevent and treat cholestatic liver injury.

Hepatoprotective Mechanisms Induced by Spinach Methanolic Extract in Rats with Hyperglycemia-An Immunohistochemical Analysis

Spinach methanolic extract (SME) has a hepatoprotective effect due to its polyphenolic antioxidants; however, its action in parenchymal (PQ) and non-parenchymal (nPQ) cells remains unknown. This study investigates the hepatoprotective effect of SME on streptozotocin-induced hyperglycemic rats (STZ), focusing on immunohistochemical analyses. Methods: The extract was prepared, and the total polyphenols and antioxidant activity were quantified. Adult male Wistar rats were divided into four groups (n = 8): normoglycemic rats (NG), STZ-induced hyperglycemic (STZ), STZ treated with 400 mg/kg SME (STZ-SME), and NG treated with SME (SME) for 12 weeks. Serum liver transaminases and lipid peroxidation levels in tissue were determined. The distribution pattern and relative levels of markers related to oxidative stress [reactive oxygen species (ROS), superoxide dismutase-1, catalase, and glutathione peroxidase-1], of cytoprotective molecules [nuclear NRF2 and heme oxygenase-1 (HO-1)], of inflammatory mediators [nuclear NF-κB, TNF-α], proliferation (PCNA), and of fibrogenesis markers [TGF-β, Smad2/3, MMP-9, and TIMP1] were evaluated. Results: SME had antioxidant capacity, and it lowered serum transaminase levels in STZ-SME compared to STZ. It reduced NOX4 staining, and lipid peroxidation levels were related to low formation of ROS. In STZ-SME, the immunostaining for antioxidant enzymes increased in nPQ cells compared to STZ. However, enzymes were also localized in extra and intracellular vesicles in STZ. Nuclear NRF2 staining and HO-1 expression in PQ and nPQ were higher in STZ-SME than in STZ. Inflammatory factors were decreased in STZ-SME and were related to the percentage decrease in NF-κB nuclear staining in nPQ cells. Similarly, TGF-β (in the sinusoids) and MMP-9 (in nPQ) were increased in the STZ-SME group compared to the other groups; however, staining for CTGF, TIMP1, and Smad2/3 was lower. Conclusions: SME treatment in hyperglycemic rats induced by STZ may have hepatoprotective properties due to its scavenger capacity and the regulation of differential expression of antioxidant enzymes between the PQ and nPQ cells, reducing inflammatory and fibrogenic biomarkers in liver tissue.

The Protective Effect and Mechanism of a Phytochemical Extract from the Wild Vegetable Shutou (Crateva unilocularis Buch.) against Acetaminophen-Induced Liver Injury in Mice

Acetaminophen (APAP) abuse is a common public health problem which can cause severe liver damage. However, strategies for dealing with this situation safely and effectively are very limited. The goal of the current work was to evaluate the protection and potential molecular mechanisms of an ethanol extract from shoots of the wild vegetable shutou (Crateva unilocularis Buch.) (ECS) against APAP-induced liver damage in mice. Mice orally received ECS for seven days (300 or 600 mg/kg b.w. per day) before being intraperitoneally injected with APAP (250 mg/kg). Results exhibited that ECS obviously decreased the content of alkaline phosphatase, alanine aminotransferase, aspartate transaminase, and malondialdehyde (p < 0.05). Catalase and superoxide dismutase were notably restored (p < 0.05), and the content of reduced glutathione was obviously increased (p < 0.05). Moreover, ECS significantly inhibited the secretion of interleukin-1β and tumor necrosis factor-α (p < 0.05). Further analyses of the mechanisms showed that ECS may alleviate oxidative stress in the liver by increasing the expression of the nuclear factor erythroid-2-related factor 2 and NADH quinone oxidoreductase 1 proteins, and may suppress liver inflammation by inhibiting the expression of the phosphorylated-inhibitor kappa B alpha/inhibitor kappa B alpha, phosphorylated-nuclear factor κB/nuclear factor κB, and cyclooxygenase-2 proteins. Meanwhile, ECS inhibited hepatocyte apoptosis by enhancing B-cell lymphoma gene 2 and suppressing Bcl-2-associated X protein. In summary, ECS may be used as a dietary supplement to prevent the liver damage caused by APAP abuse.

Molecular mechanisms of hepatoprotective effect of tectorigenin against ANIT-induced cholestatic liver injury: Role of FXR and Nrf2 pathways

Cholestatic liver injury is caused by toxic action or allergic reaction, resulting in abnormality of bile formation and excretion. Few effective therapies have become available for the treatment of cholestasis. Herein, we found that tectorigenin (TG), a natural isoflavone, showed definite protective effects on alpha-naphthylisothiocyanate (ANIT)-induced cholestatic liver injury, significantly reversing the abnormality of plasma alanine/aspartate aminotransferase, total/direct bilirubin and alkaline phosphatase, as well as hepatic reactive oxygen species, catalase and superoxide dismutase. Importantly, the targeted metabolomic determination found that BA homeostasis could be well maintained in TG-treated cholestatic mice, especially the levels of glycocholic acid, tauromuricholic acid, taurocholic acid, taurolithocholic acid, tauroursodeoxycholic acid and taurodeoxycholic acid. Overall, primary/secondary and amidated/unamidated bile acid (BA) levels were significantly altered upon ANIT stimulation but could be restored by TG intervention to certain extents. In addition, TG boosted the expression of farnesoid x receptor (FXR), which in turn upregulated multidrug resistance protein 2 (MRP2) and bile salt export pump (BSEP) to accelerate the excretion of BA. Meanwhile, TG enhanced the expression of Nrf2 and its upstream genes PI3K/Akt and downstream target genes HO-1, NQO1, GCLC and GCLM to strengthen the antioxidant capacity. Taken together, TG plays a vital role in maintaining BA homeostasis and ameliorating cholestatic liver injury through regulating FXR-mediated BA efflux and Nrf2-mediated antioxidative pathways.

Oxidative stress in Wernicke's encephalopathy

Wernicke's encephalopathy (WE) is a severe life-threatening disease that occurs due to vitamin B1 (thiamine) deficiency (TD). It is characterized by acute mental disorder, ataxia, and ophthalmoplegia. TD occurs because of the following reasons: insufficient intake, increased demand, and long-term drinking due to corresponding organ damage or failure. Recent studies showed that oxidative stress (OS) can damage organs and cause TD in the brain, which further leads to neurodegenerative diseases, such as WE. In this review, we discuss the effects of TD caused by OS on multiple organ systems, including the liver, intestines, and brain in WE. We believe that strengthening the human antioxidant system and reducing TD can effectively treat WE.

Intestinal microbiomics and hepatic metabolomics insights into the potential mechanisms of probiotic Bifidobacterium pseudolongum CCFM1253 preventing acute liver injury in mice

BACKGROUND

Bifidobacterium pseudolongum is widely exists in mammal gut and its abundance is associated with human and animal health. The present study aimed to investigate the potential mechanisms of B. pseudolongum CCFM1253 on protecting against lipopolysaccharide (LPS)-induced acute liver injury (ALI) by metagenomic analysis and liver metabolomic profiles.

RESULTS

Bifidobacterium pseudolongum CCFM1253 preintervention remarkably attenuated the influence of LPS on serum alanine transaminase and aspartate amino transferase activities. B. pseudolongum CCFM1253 preintervention remarkably attenuated the inflammation responses (tumor necrosis factor-α, interleukin-1β, and interleukin-6) and elevated antioxidative enzymes activities [total antioxidant capacity, superoxide dismutase, catalase, and glutathione peroxidase] in ALI mice by intervening in the Nf-kβ and Nrf2 pathways, respectively. Bifidobacterium pseudolongum CCFM1253 treatment elevated the proportion of Alistipes and Bifidobacterium, and decreased the proportion of uncultured Bacteroidales bacterium, Muribaculum, Parasutterella and Ruminococcaceae UCG-010 in ALI mice, which were strongly correlated with the inhibition of inflammation responses and oxidative stress. Untargeted liver metabolomics exhibited that the hepatoprotective efficacy of B. pseudolongum CCFM1253 might be achieved by altering liver metabolites-related riboflavin metabolism, phenylalanine metabolism, alanine, citrate cycle (tricarboxylic acid cycle), and so on. Furthermore, riboflavin exposure could control the contents of malondialdehyde, superoxide dismutase, and catalase in hydrogen peroxide-treated HepG2 cells.

CONCLUSION

Bifidobacterium pseudolongum CCFM1253 can effectively alleviate inflammatory response and oxidative stress, and regulate the intestinal microbiota composition and liver metabolism, and elevate the liver riboflavin content in LPS-treated mice. Therefore, B. pseudolongum CCFM1253 could serves as a potential probiotic to ameliorate the host health. © 2023 Society of Chemical Industry.

Calculus Bovis Sativus alleviates estrogen cholestasis-induced gut and liver injury in rats by regulating inflammation, oxidative stress, apoptosis, and bile acid profiles

ETHNOPHARMACOLOGICAL RELEVANCE

Natural Calculus Bovis (NCB) is a traditional Chinese medicine used for anti-inflammation, treating fever, pain, sedation, and recovering hepatobiliary function. Calculus Bovis Sativus (CBS), produced from in vitro artificial cultivation by bioengineering techniques, acts as an ideal substitute for NCB when treating various diseases.

AIM OF THE STUDY

Gut-liver injury is an important pathological feature of several cholestatic liver diseases, including estrogen-induced cholestasis (EIC). The strong link between cholestatic liver injury and intestinal damage emphasizes the need of considering gut-liver integrity during treatment. The purpose of this study is to look into the pharmacological activities of CBS on EIC-induced gut and liver damage.

MATERIALS AND METHODS

EIC-induced cholestatic rats were given oral gavage daily for five days with or without CBS (150 mg/kg). The liver/body weight, serum biochemistry, and tissue histopathology were then evaluated. Quantitative real-time PCR, Western blot analyses, and immunofluorescence were used to determine the gene expression associated with pathological alterations of the liver and intestine in EIC-induced cholestatic rats. Bile acid profiles within enterohepatic circulation were detected by liquid chromatography-mass spectrometry.

RESULTS

CBS significantly reduced relative liver weight, restored serum biochemistry levels, and improved the hepatic and intestinal pathological damage in EIC model rats. CBS reduced EIC-induced hepatic inflammation by inactivation of the NF-κB signaling and inhibition of TNFα, IL-1β, and IL-6 expression. CBS alleviated EIC-induced hepatic and intestinal oxidative stress by regulating Nrf2-GCLM/GCLC and Nrf2-HO-1 pathways, respectively. CBS treatment upregulated Bcl-2 and downregulated Bax and cleaved caspase3 to improve EIC-induced hepatic and intestinal cell apoptosis. Additionally, CBS reversed the disorders of bile acid profiles in the enterohepatic circulation by reducing bile acid accumulation in the liver and plasma and increasing bile excretion and intestinal reabsorption of bile acids.

CONCLUSION

CBS alleviates EIC-induced hepatic and intestinal injury through regulating inflammation, oxidative stress, apoptosis, and bile acid profiles. These results suggest that CBS or drugs targeting the gut-liver axis may be effective therapeutic agents for cholestasis.

NRF2 and FXR dual signaling pathways cooperatively regulate the effects of oleanolic acid on cholestatic liver injury

BACKGROUND

Previous studies have shown that the anti-cholestatic effect of oleanolic acid (OA) is associated with FXR and NRF2. However, how the two signaling pathways cooperate to regulate the anti-cholestatic effect of OA remains unclear.

PURPOSE

This study aimed to further demonstrate the effect of OA on alpha-naphthyl isothiocyanate (ANIT)-induced cholestatic liver injury and the interaction mechanism between NRF2 and FXR signaling pathways in maintaining bile acid homeostasis.

METHODS

Gene knockout animals and cell models, metabolomics analysis, and co-immunoprecipitation were used to investigate the mechanism of OA against cholestatic liver injury.

RESULTS

The effect of OA against ANIT-induced liver injury in rats was dramatically reduced after Nrf2 gene knockdown. With the silencing of Fxr, the hepatoprotective effect of OA was weakened, but it still effectively alleviated cholestatic liver injury in rats. In L02 cells, OA can up-regulate the levels of NRF2, FXR, BSEP and UGT1A1, and reduce the expression of CYP7A1. Silencing of NRF2 or FXR significantly attenuated the protective effect of OA on ANIT-induced L02 cell injury and its regulation on downstream target genes, and the influence of NRF2 gene silencing on OA appeared to be greater. The NRF2 activator sulforaphane, and the FXR activator GW4064 both remarkably promoted NRF2 binding to P300 and FXR to RXRα, but reduced β-catenin binding to P300 and β-catenin binding to FXR.

CONCLUSION

The effect of OA on cholestatic liver injury is closely related to the simultaneous activation of NRF2 and FXR dual signaling pathways, in which NRF2 signaling pathway plays a more important role. The dual signaling pathways of NRF2 and FXR cooperatively regulate bile acid metabolic homeostasis through the interaction mechanism with β-catenin/P300.

Exploration of the Potential Targets and Molecular Mechanism of Carthamus tinctorius L. for Liver Fibrosis Based on Network Pharmacology and Molecular Docking Strategy

Carthamus tinctorius L. (Honghua, HH) is an herbal medicine and functional food widely used to treat chronic liver diseases, including liver fibrosis. By using network pharmacology and molecular docking experiments, the present study aims to determine the bioactive components, potential targets, and molecular mechanisms of HH for treating liver fibrosis. The components of HH were screened from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform and literature, and the SwissTargetPrediction database was used to predict the treatment targets of HH. Genecards and DisGeNET databases contained targets for liver fibrosis, and the STRING database provided networks of protein–protein interactions. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed using the Database of Annotation, Visualization and Integrated Discovery. The protein–protein interactive network and drug–component–major target–pathway interactive network were visualized and analyzed by Cytoscape software. Finally, Autodock Vina and Discovery Studio software were used for molecular docking Validation. A total of 23 candidate bioactive compounds with 187 treatment targets of HH were acquired from the databases and literature. A total of 121 overlapping targets between HH and liver fibrosis were found to provide the molecular basis for HH on liver fibrosis. Quercetin, beta carotene, and lignan were identified as key components with targeting to ESR1, PIK3CA, and MTOR. HH is engaged in the intervention of various signaling cascades associated with liver fibrosis, such as PI3K/AKT/mTOR pathway, MAPK pathway, and PPAR pathway. In conclusion, HH treats liver fibrosis through multi-component, multi-target, and multi-pathway mechanisms.