Impairment of Akt activity by CYP2E1 mediated oxidative stress is involved in chronic ethanol-induced fatty liver

Metallofullerenol alleviates alcoholic liver damage via ROS clearance under static magnetic and electric fields

Alcoholic liver disease (ALD) is a common chronic redox disease caused by increased alcohol consumption. Abstinence is a major challenge for people with alcohol dependence, and approved drugs have limited efficacy. Therefore, this study aimed to explore a new treatment strategy for ALD using ferroferric oxide endohedral fullerenol (Fe3O4@C60(OH)n) in combination with static magnetic and electric fields (sBE). The primary hepatocytes of 8-9-week-old female BALB/c mice were used to evaluate the efficacy of the proposed combination treatment. A mouse chronic binge ethanol feeding model was established to determine the alleviatory effect of Fe3O4@C60(OH)n on liver injury under sBE exposure. Furthermore, the ability of Fe3O4@C60(OH)n to eliminate •OH was evaluated. Alcohol-induced hepatocyte and mitochondrial damage were reversed in vitro. Additionally, the combination therapy reduced liver damage, alleviated oxidative stress by improving antioxidant levels, and effectively inhibited liver lipid accumulation in animal experiments. Here, we used a combination of magnetic derivatives of fullerenol and sBE to further improve the ROS clearance rate, thereby alleviating ALD. The developed combination treatment may effectively improve alcohol-induced liver damage and maintain redox balance without apparent toxicity, thereby enhancing therapy aimed at ALD and other redox diseases.

Biphasic effects of ethanol consumption on N,N-dimethylformamide-induced liver injury in mice

N,N-Dimethylformamide (DMF) is a well-documented occupational hazardous material, which can induce occupational liver injury. The current study was designed to investigate whether ethanol consumption can affect DMF-induced hepatotoxicity and the potential underlying mechanisms involved. We found that a single dose of ethanol (1.25, 2.5, or 5 g/kg bw by gavage) significantly repressed the increase in serum alanine transaminase (ALT) and aspartate transaminase (AST) activities and alleviated the liver histopathological changes in mice challenged with 3 g/kg DMF. In contrast, long-term moderate drinking (2.5 g/kg bw) significantly aggravated the repeated DMF (0.7 g/kg bw) exposure-induced increase in the serum ALT and AST activities. Mechanistically, acute ethanol consumption suppressed DMF-induced activation of the NLR family pyrin domain-containing protein 3 (NLRP3) inflammasome, while long-term moderate ethanol consumption promoted hepatocyte apoptosis in the mouse liver. Notably, cytochrome P4502E1 (CYP2E1) protein level and activity in mouse livers were not significantly affected by ethanol per se in the two models. These results confirm that regular drinking can increase the risk of DMF-induced hepatotoxicity, and suggest that DMF-handling workers should avoid consuming ethanol to reduce the risk of DMF-indued liver injury.

CYP2E1 deficit mediates cholic acid-induced malignant growth in hepatocellular carcinoma cells

BACKGROUND

Increased level of serum cholic acid (CA) is often accompanied with decreased CYP2E1 expression in hepatocellular carcinoma (HCC) patients. However, the roles of CA and CYP2E1 in hepatocarcinogenesis have not been elucidated. This study aimed to investigate the roles and the underlying mechanisms of CYP2E1 and CA in HCC cell growth.

METHODS

The proteomic analysis of liver tumors from DEN-induced male SD rats with CA administration was used to reveal the changes of protein expression in the CA treated group. The growth of CA-treated HCC cells was examined by colony formation assays. Autophagic flux was assessed with immunofluorescence and confocal microscopy. Western blot analysis was used to examine the expression of CYP2E1, mTOR, AKT, p62, and LC3II/I. A xenograft tumor model in nude mice was used to examine the role of CYP2E1 in CA-induced hepatocellular carcinogenesis. The samples from HCC patients were used to evaluate the clinical value of CYP2E1 expression.

RESULTS

CA treatment significantly increased the growth of HCC cells and promoted xenograft tumors accompanied by a decrease of CYP2E1 expression. Further studies revealed that both in vitro and in vivo, upregulated CYP2E1 expression inhibited the growth of HCC cells, blocked autophagic flux, decreased AKT phosphorylation, and increased mTOR phosphorylation. CYP2E1 was involved in CA-activated autophagy through the AKT/mTOR signaling. Finally, decreased CYP2E1 expression was observed in the tumor tissues of HCC patients and its expression level in tumors was negatively correlated with the serum level of total bile acids (TBA) and gamma-glutamyltransferase (GGT).

CONCLUSIONS

CYP2E1 downregulation contributes to CA-induced HCC development presumably through autophagy regulation. Thus, CYP2E1 may serve as a potential target for HCC drug development.

Retinoic acid induced specific changes in the phosphoproteome of C17.2 neural stem cells

Retinoic acid (RA), a vitamin A derivative, is an effective cell differentiating factor which plays critical roles in neuronal differentiation induction and the production of neurotransmitters in neurons. However, the specific changes in phosphorylation levels and downstream signalling pathways associated with RA remain unclear. This study employed qualitative and quantitative phosphoproteomics approaches based on mass spectrometry to investigate the phosphorylation changes induced by RA in C17.2 neural stem cells (NSCs). Dimethyl labelling, in conjunction with TiO2 phosphopeptide enrichment, was utilized to profile the phosphoproteome of self-renewing and RA-induced differentiated cells in C17.2 NSCs. The results of our study revealed that, qualitatively, 230 and 14 phosphoproteins were exclusively identified in the self-renewal and RA-induced groups respectively. Quantitatively, we successfully identified and quantified 177 unique phosphoproteins, among which 70 exhibited differential phosphorylation levels. Analysis of conserved phosphorylation motifs demonstrated enrichment of motifs corresponding to cyclin-dependent kinase and MAPK in the RA-induced group. Additionally, through a comprehensive literature and database survey, we found that the differentially expressed proteins were associated with the Wnt/β-catenin and Hippo signalling pathways. This work sheds light on the changes in phosphorylation levels induced by RA in C17.2 NSCs, thereby expanding our understanding of the molecular mechanisms underlying RA-induced neuronal differentiation.

Gehua Jiejiu Dizhi decoction ameliorates alcoholic fatty liver in mice by regulating lipid and bile acid metabolism and with exertion of antioxidant stress based on 4DLabel-free quantitative proteomic study

OBJECTIVE

To analyze the effect and molecular mechanism of Gehua Jiejiu Dizhi decoction (, GJDD) on alcoholic fatty live disease (AFLD) by using proteomic methods.

METHODS

The male C57BL/6J mouse were randomly divided into four groups: control group, model group, GJDD group and resveratrol group. After the AFLD model was successfully prepared by intragastric administration of alcohol once on the basis of the Lieber-DeCarli classical method, the GJDD group and resveratrol group were intragastrically administered with GJDD (4900 mg/kg) and resveratrol (400 mg/kg) respectively, once a day for 9 d. The fat deposition of liver tissue was observed and evaluated by oil red O (ORO) staining. 4DLabel-free quantitative proteome method was used to determine and quantify the protein expression in liver tissue of each experimental group. The differentially expressed proteins were screened according to protein expression differential multiples, and then analyzed by Gene ontology classification and Kyoto Encyclopedia of Genes and Genomes pathway enrichment. Finally, expression validation of the differentially co-expressed proteins from control group, model group and GJDD group were verified by targeted proteomics quantification techniques.

RESULTS

In semiquantitative analyses of ORO, all kinds of steatosis (ToS, MaS, and MiS) were evaluated higher in AFLD mice compared to those in GJDD or resveratrol-treated mice. 4DLabel-free proteomics analysis results showed that a total of 4513 proteins were identified, of which 3763 proteins were quantified and 946 differentially expressed proteins were screened. Compared with the control group, 145 proteins were up-regulated and 148 proteins were down-regulated in the liver tissue of model group. In addition, compared with the model group, 92 proteins were up-regulated and 135 proteins were down-regulated in the liver tissue of the GJDD group. 15 differentially co-expressed proteins were found between every two groups (model group vs control group, GJDD group vs model group and GJDD group vs control group), which were involved in many biological processes. Among them, 11 differentially co-expressed key proteins (Aox3, H1-5, Fabp5, Ces3a, Nudt7, Serpinb1a, Fkbp11, Rpl22l1, Keg1, Acss2 and Slco1a1) were further identified by targeted proteomic quantitative technology and their expression patterns were consistent with the results of 4D label-free proteomic analysis.

CONCLUSIONS

Our study provided proteomics-based evidence that GJDD alleviated AFLD by modulating liver protein expression, likely through the modulation of lipid metabolism, bile acid metabolism and with exertion of antioxidant stress.

A functional chicken-liver hydrolysate-based supplement ameliorates alcohol liver disease via regulation of antioxidation, anti-inflammation, and antiapoptosis

Tons of broiler livers are produced yearly in Taiwan but always considered waste. Our team has successfully patented and characterized a chicken-liver hydrolysate (CLH) with several biofunctions. Chronic alcohol consumption causes hepatosteatosis or even hepatitis, cirrhosis, and cancers. This study was to investigate the hepatoprotection of CLH-based supplement (GBHP01™) against chronic alcohol consumption. Results showed that GBHP01™ could reduce (p < .05) enlarged liver size, lipid accumulation/steatosis scores, and higher serum AST, ALT, γ-GT, triglyceride, and cholesterol levels induced by an alcoholic liquid diet. GBHP01™ reduced liver inflammation and apoptosis in alcoholic liquid-diet-fed mice via decreasing TBARS, interleukin-6, interleukin-1β, and tumor necrosis factor-α levels, increasing reduced GSH/TEAC levels and activities of SOD, CAT and GPx, as well as downregulating CYP2E1, BAX/BCL2, Cleaved CASPASE-9/Total CASPASE-9 and Active CASPASE-3/Pro-CASPASE-3 (p < .05). Furthermore, GBHP01™ elevated hepatic alcohol metabolism (ADH and ALDH activities) (p < .05). In conclusion, this study prove the hepatoprotection of GBHP01™ against alcohol consumption.

Glucosamine attenuates alcohol-induced acute liver injury via inhibiting oxidative stress and inflammation

Alcohol liver disease (ALD) is a liver disease caused by long-term heavy drinking. Glucosamine (GLC) is an amino monosaccharide that plays a very important role in the synthesis of human and animal cartilage. GLC is commonly used in the treatment of mild to moderate osteoarthritis and has good anti-inflammatory and antioxidant properties. In this study, alcoholic injury models were constructed in mice and human normal hepatocyte L02 cells to explore the protective effect and mechanism of GLC on ALD. Mice were given GLC by gavage for 30 days. Liver injury models of both mice and L02 cells were produced by ethanol. Detecting the levels of liver injury biomarkers, lipid metabolism, oxidative stress biomarkers, and inflammatory factors through different reagent kits. Exploring oxidative and inflammatory pathways in mouse liver tissue through Western blot and RT-PCR. The results showed that GLC can significantly inhibit the abnormal increase of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), triglycerides (TG), total cholesterol (TC), very low density lipoprotein (VLDL), low-density lipoprotein cholesterol (LDL-C), and can significantly improve the level of high-density lipoprotein cholesterol (HDL-C). In addition, GLC intervention significantly improved alcohol induced hepatic oxidative stress by reducing the levels of malondialdehyde (MDA) and, increasing the levels of glutathione (GSH), catalase (CAT) and superoxide dismutase (SOD) in the liver. Further mechanisms suggest that GLC can inhibit the expression of ethanol metabolism enzyme cytochrome P4502E1 (CYP2E1), activate the antioxidant pathway Keap1/Nrf2/HO-1, down-regulate the phosphorylation of MAPK and NF-κB signaling pathways, and thus reduce the expression of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6). Therefore, GLC may be a significant candidate functional food for attenuating alcohol induced acute liver injury.

Protective Effect of Monoterpene Isoespintanol in a Rat Model of Prediabetes Induced by Fructose

A high-fructose diet (HFD) induces murine alterations like those recorded in human prediabetes. Protective effects of isoespintanol (monoterpene isolated from Oxandra cf. xylopioides) on changes induced by HFD were evaluated. Animals were maintained for 21 days with a standard diet (C), 10% fructose (F), and F plus isoespintanol (FI, 10 mg/kg, i.p.). Glycemia, triglyceridemia, total and HDL-cholesterol, and insulin resistance index (IRX) were determined. Intraperitoneal glucose tolerance test (IGTT) was performed. In the liver, we measured glycogen, lipogenic gene expression (SREBP-1c, GPAT, FAS, and CPT1), oxidative stress (GSH and 3'-nitrotyrosine content), inflammation markers (iNOS, TNF-α, and PAI-1 gene expression; iNOS and COX-2 protein levels), p-eNOS, p-Akt, and p-GSK3β protein levels. Isoespintanol corrected enhanced triglycerides, lipogenic genes, and IRX, and reduced HDL-cholesterol induced by HFD. Increased liver glycogen and inflammatory markers and decreased GSH, p-Akt, and p-GSK3β measured in F rats were reversed by isoespintanol, and p-eNOS/e-NOS and iNOS/GADPH ratios were normalized. Isoespintanol restored glucose tolerance (IGTT) compared to F rats. These results demonstrate for the first time that isoespintanol prevents endocrine-metabolic alterations induced by HFD in prediabetic rats. These effects could be mediated by Akt/eNOS and Akt/GSK3β pathways, suggesting its possible use as a therapeutic tool for the prevention of diabetes at early stages of its development (prediabetes).

Branched-chain amino acid modulation of lipid metabolism, gluconeogenesis, and inflammation in a finishing pig model: targeting leucine and valine

Branched-chain amino acids (BCAAs) play a regulatory role in adipogenesis and energy balance. Therefore, this study aimed to investigate the impact of BCAA supplements, especially leucine (Leu) and valine (Val) supplementation, on lipid metabolism and related disorders in a finishing pig model. The results demonstrated that Leu (1%) and Val decreased serum as well as hepatic lipid accumulation. Moreover, metabolomics and lipidomics analyses revealed that Leu and Val markedly downregulated the level of various lipid species in the liver. This outcome may be explained by Leu and Val promoting cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA)/hormone-sensitive triglyceride lipase (HSL) signaling pathways. Leu and Val altered the fatty acid composition in distinct adipose tissues and decreased the levels of inflammatory factors. Additionally, they significantly decreased back fat thickness, and the results of the fatty acid profiles demonstrated that Leu and Val significantly increased the levels of monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) while decreasing those of saturated fatty acids (SFAs), especially in back fat and abdominal fat. Besides, Leu and Val restored glucose homeostasis by suppressing gluconeogenesis through the serine/threonine protein kinase (AKT)/transcription factor forkhead box O1 (FOXO1) signaling pathway in the liver and back fat. In summary, these results suggest that Leu and Val may serve as key regulators for modulating lipid metabolism and steatosis.

Glutamine Ameliorates Liver Steatosis via Regulation of Glycolipid Metabolism and Gut Microbiota in High-Fat Diet-Induced Obese Mice

Obesity and its associated conditions, such as nonalcoholic fatty liver disease (NAFLD), are risk factors for health. The aim of this study was to explore the effects of glutamine (Gln) on liver steatosis induced by a high-fat diet (HFD) and HEPG2 cells induced by oleic acid. Gln demonstrated a positive influence on hepatic homeostasis by suppressing acetyl CoA carboxylase (ACC) and fatty acid synthase (FAS) and promoting sirtuin 1 (SIRT1) expression while improving glucose metabolism by regulating serine/threonine protein kinase (AKT)/factor forkhead box O1 (FOXO1) signals in vivo and in vitro. Obese Gln-fed mice had higher colonic short-chain fatty acid (SCFA) contents and lower inflammation factor protein levels in the liver, HEPG2 cells, and jejunum. Gln-treated obese mice had an effective decrease in Firmicutes abundance. These findings indicate that Gln serves as a nutritional tool in managing obesity and related disorders.

Stress mechanism involved in the progression of alcoholic liver disease and the therapeutic efficacy of nanoparticles

Alcoholic liver disease (ALD) poses a significant threat to human health, with excessive alcohol intake disrupting the immunotolerant environment of the liver and initiating a cascade of pathological events. This progressive disease unfolds through fat deposition, proinflammatory cytokine upregulation, activation of hepatic stellate cells, and eventual development of end-stage liver disease, known as hepatocellular carcinoma (HCC). ALD is intricately intertwined with stress mechanisms such as oxidative stress mediated by reactive oxygen species, endoplasmic reticulum stress, and alcohol-induced gut dysbiosis, culminating in increased inflammation. While the initial stages of ALD can be reversible with diligent care and abstinence, further progression necessitates alternative treatment approaches. Herbal medicines have shown promise, albeit limited by their poor water solubility and subsequent lack of extensive exploration. Consequently, researchers have embarked on a quest to overcome these challenges by delving into the potential of nanoparticle-mediated therapy. Nanoparticle-based treatments are being explored for liver diseases that share similar mechanisms with alcoholic liver disease. It underscores the potential of these innovative approaches to counteract the complex pathogenesis of ALD, providing new avenues for therapeutic intervention. Nevertheless, further investigations are imperative to fully unravel the therapeutic potential and unlock the promise of nanoparticle-mediated therapy specifically tailored for ALD treatment.

Stress mechanism involved in the progression of alcoholic liver disease and the therapeutic efficacy of nanoparticles

Alcoholic liver disease (ALD) poses a significant threat to human health, with excessive alcohol intake disrupting the immunotolerant environment of the liver and initiating a cascade of pathological events. This progressive disease unfolds through fat deposition, proinflammatory cytokine upregulation, activation of hepatic stellate cells, and eventual development of end-stage liver disease, known as hepatocellular carcinoma (HCC). ALD is intricately intertwined with stress mechanisms such as oxidative stress mediated by reactive oxygen species, endoplasmic reticulum stress, and alcohol-induced gut dysbiosis, culminating in increased inflammation. While the initial stages of ALD can be reversible with diligent care and abstinence, further progression necessitates alternative treatment approaches. Herbal medicines have shown promise, albeit limited by their poor water solubility and subsequent lack of extensive exploration. Consequently, researchers have embarked on a quest to overcome these challenges by delving into the potential of nanoparticle-mediated therapy. Nanoparticle-based treatments are being explored for liver diseases that share similar mechanisms with alcoholic liver disease. It underscores the potential of these innovative approaches to counteract the complex pathogenesis of ALD, providing new avenues for therapeutic intervention. Nevertheless, further investigations are imperative to fully unravel the therapeutic potential and unlock the promise of nanoparticle-mediated therapy specifically tailored for ALD treatment.

Cyp2e1 knockdown attenuates high glucose-induced apoptosis and oxidative stress of cardiomyocytes by activating PI3K/Akt signaling

AIMS

Cyp2e1 is a crucial CYP450 enzyme participating in diabetes and cardiovascular disorder. However, the role of Cyp2e1 in diabetic cardiomyopathy (DCM) has never been reported. Thus, we intended to identify the effects of Cyp2e1 on cardiomyocytes under high glucose (HG) conditions.

METHODS

Identification of differentially expressed genes in DCM and control rats was performed using bioinformatics analysis based on GEO database. The Cyp2e1-knockdown H9c2 and HL-1 cells were established through transfection with si-Cyp2e1. Western blot analysis was performed to determine the expression levels of Cyp2e1, apoptosis-related proteins and PI3K/Akt signaling-associated proteins. TUNEL assay was performed to assess apoptotic rate. Reactive oxygen species (ROS) generation was examined by DCFH2-DA staining assay.

RESULTS

From the bioinformatics analysis, Cyp2e1 was confirmed as an upregulated gene in DCM tissues. In vitro assays proved that Cyp2e1 expression was markedly increased in HG-induced H9c2 and HL-1 cells. Cyp2e1 knockdown attenuated HG-induced apoptosis in both H9c2 and HL-1 cells, as proved by deceased apoptotic rate, relative cleaved caspase-3/caspase-3 level, and caspase-3 activity. Cyp2e1 knockdown reduced ROS generation and elevated the expression level of nuclear Nrf2 in HG-induced H9c2 and HL-1 cells. Increased relative levels of p-PI3K/PI3K and p-Akt/Akt were found in Cyp2e1-knockdown H9c2 and HL-1 cells. Inhibition of PI3K/Akt using LY294002 reversed the inhibitory effects of Cyp2e1 knockdown on cell apoptosis and ROS generation on cardiomyocytes.

CONCLUSIONS

Cyp2e1 knockdown attenuated HG-induced apoptosis and oxidative stress by activating PI3K/Akt signaling in cardiomyocytes. These findings suggested that Cyp2e1 might be potentially used as an effective therapeutic strategy for DCM.

Pathogenesis of Alcoholic Fatty Liver a Narrative Review

Alcohol effect hepatic lipid metabolism through various mechanisms, leading synergistically to an accumulation of fatty acids (FA) and triglycerides. Obesity, as well as dietary fat (saturated fatty acids (FA) versus poly-unsaturated fatty acids (PUFA)) may modulate the hepatic fat. Alcohol inhibits adenosine monophosphate activated kinase (AMPK). AMPK activates peroxisome proliferator activated receptor a (PPARα) and leads to a decreased activation of sterol regulatory element binding protein 1c (SRABP1c). The inhibition of AMPK, and thus of PPARα, results in an inhibition of FA oxidation. This ß-oxidation is further reduced due to mitochondrial damage induced through cytochrome P4502E1 (CYP2E1)-driven oxidative stress. Furthermore, the synthesis of FAs is stimulated through an activation of SHREP1. In addition, alcohol consumption leads to a reduced production of adiponectin in adipocytes due to oxidative stress and to an increased mobilization of FAs from adipose tissue and from the gut as chylomicrons. On the other side, the secretion of FAs via very-low-density lipoproteins (VLDL) from the liver is inhibited by alcohol. Alcohol also affects signal pathways such as early growth response 1 (Egr-1) associated with the expression of tumour necrosis factor α (TNF α), and the mammalian target of rapamycin (mTOR) a key regulator of autophagy. Both have influence the pathogenesis of alcoholic fatty liver. Alcohol-induced gut dysbiosis contributes to the severity of ALD by increasing the metabolism of ethanol in the gut and promoting intestinal dysfunction. Moreover, pathogen-associated molecular patterns (PAMPS) via specific Toll-like receptor (TLR) bacterial overgrowth leads to the translocation of bacteria. Endotoxins and toxic ethanol metabolites enter the enterohepatic circulation, reaching the liver and inducing the activation of the nuclear factor kappa-B (NFκB) pathway. Pro-inflammatory cytokines released in the process contribute to inflammation and fibrosis. In addition, cellular apoptosis is inhibited in favour of necrosis.

Alcohol, White Adipose Tissue, and Brown Adipose Tissue: Mechanistic Links to Lipogenesis and Lipolysis

According to data from the World Health Organization, there were about 3 million deaths caused by alcohol consumption worldwide in 2016, of which about 50% were related to liver disease. Alcohol consumption interfering with the normal function of adipocytes has an important impact on the pathogenesis of alcoholic liver disease. There has been increasing recognition of the crucial role of adipose tissue in regulating systemic metabolism, far beyond that of an inert energy storage organ in recent years. The endocrine function of adipose tissue is widely recognized, and the significance of the proteins it produces and releases is still being investigated. Alcohol consumption may affect white adipose tissue (WAT) and brown adipose tissue (BAT), which interact with surrounding tissues such as the liver and intestines. This review briefly introduces the basic concept and classification of adipose tissue and summarizes the mechanism of alcohol affecting lipolysis and lipogenesis in WAT and BAT. The adipose tissue-liver axis is crucial in maintaining lipid homeostasis within the body. Therefore, this review also demonstrates the effects of alcohol consumption on the adipose tissue-liver axis to explore the role of alcohol consumption in the crosstalk between adipose tissue and the liver.

Effect of Europinidin against Alcohol-Induced Liver Damage in Rats by Inhibiting the TNF-α/TGF-β/IFN-γ/NF-kB/Caspase-3 Signaling Pathway

BACKGROUND

The effect of europinidin on alcoholic liver damage in rats was examined in this research.

METHODS

A total of 24 Wistar rats were grouped in the same way into four groups: normal control (normal), ethanol control (EtOH), europinidin low dose (10 mg/kg), and europinidin higher dose (20 mg/kg). The test group rats were orally treated with europinidin-10 and europinidin-20 for 4 weeks, whereas 5 mL/kg distilled water was administered to control rats. In addition, 1 h after the last dose of the above-mentioned oral treatment, 5 mL/kg (i.p.) EtOH was injected to induce liver injury. After 5 h of EtOH treatment, samples of blood were withdrawn for biochemical estimations.

RESULTS

Administration of europinidin at both doses restored all of the estimated serum, i.e., liver function tests (ALT, AST, ALP), biochemical test (Creatinine, albumin, BUN, direct bilirubin, and LDH), lipid assessment (TC and TG), endogenous antioxidants (GSH-Px, SOD, and CAT), malondialdehyde (MDA), nitric oxide (NO), cytokines (TGF-β, TNF-α, IL-1β, IL-6, IFN-γ, and IL-12), caspase-3, and nuclear factor kappa B (NF-κB) associated with the EtOH group.

CONCLUSION

The results of the investigation showed that europinidin had favorable effects in rats given EtOH and may have hepatoprotective potential property.

Pathogenic mechanisms and regulatory factors involved in alcoholic liver disease

Alcoholism is a widespread and damaging behaviour of people throughout the world. Long-term alcohol consumption has resulted in alcoholic liver disease (ALD) being the leading cause of chronic liver disease. Many metabolic enzymes, including alcohol dehydrogenases such as ADH, CYP2E1, and CATacetaldehyde dehydrogenases ALDHsand nonoxidative metabolizing enzymes such as SULT, UGT, and FAEES, are involved in the metabolism of ethanol, the main component in alcoholic beverages. Ethanol consumption changes the functional or expression profiles of various regulatory factors, such as kinases, transcription factors, and microRNAs. Therefore, the underlying mechanisms of ALD are complex, involving inflammation, mitochondrial damage, endoplasmic reticulum stress, nitrification, and oxidative stress. Moreover, recent evidence has demonstrated that the gut-liver axis plays a critical role in ALD pathogenesis. For example, ethanol damages the intestinal barrier, resulting in the release of endotoxins and alterations in intestinal flora content and bile acid metabolism. However, ALD therapies show low effectiveness. Therefore, this review summarizes ethanol metabolism pathways and highly influential pathogenic mechanisms and regulatory factors involved in ALD pathology with the aim of new therapeutic insights.

Scutellarin prevents acute alcohol-induced liver injury via inhibiting oxidative stress by regulating the Nrf2/HO-1 pathway and inhibiting inflammation by regulating the AKT, p38 MAPK/NF-κB pathways

Alcoholic liver disease (ALD) is the most frequent liver disease worldwide, resulting in severe harm to personal health and posing a serious burden to public health. Based on the reported antioxidant and anti-inflammatory capacities of scutellarin (SCU), this study investigated its protective role in male BALB/c mice with acute alcoholic liver injury after oral administration (10, 25, and 50 mg/kg). The results indicated that SCU could lessen serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels and improve the histopathological changes in acute alcoholic liver; it reduced alcohol-induced malondialdehyde (MDA) content and increased glutathione peroxidase (GSH-Px), catalase (CAT), and superoxide dismutase (SOD) activity. Furthermore, SCU decreased tumor necrosis factor-‍α (TNF-‍α), interleukin-6 (IL-6), and IL-‍1β messenger RNA (mRNA) expression levels, weakened inducible nitric oxide synthase (iNOS) activity, and inhibited nucleotide-binding oligomerization domain (NOD)‍-like receptor protein 3 (NLRP3) inflammasome activation. Mechanistically, SCU suppressed cytochrome P450 family 2 subfamily E member 1 (CYP2E1) upregulation triggered by alcohol, increased the expression of oxidative stress-related nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) pathways, and suppressed the inflammation-related degradation of inhibitor of nuclear factor-‍κB (NF-‍κB)‍-‍α (IκBα) as well as activation of NF‍-‍κB by mediating the protein kinase B (AKT) and p38 mitogen-activated protein kinase (MAPK) pathways. These findings demonstrate that SCU protects against acute alcoholic liver injury via inhibiting oxidative stress by regulating the Nrf2/HO-1 pathway and suppressing inflammation by regulating the AKT, p38 MAPK/NF-κB pathways.

Stereoisomers of octahydrocurcumin, the hydrogenated metabolites of curcumin, display stereoselective activity on the CYP2E1 enzyme in L-02 cells

As the final hydrogenated metabolite of curcumin, octahydrocurcumin (OHC) exhibits increased powerful bioactivities. The chiral and symmetric chemical structure indicated that there were two OHC stereoisomers, (3R,5S)-octahydrocurcumin (Meso-OHC) and (3S,5S)-octahydrocurcumin ((3S,5S)-OHC), which may induce different effects on metabolic enzymes and bioactivities. Thus, we detected OHC stereoisomers from rat metabolites (blood, liver, urine and feces) after oral administration of curcumin. In addition, OHC stereoisomers were prepared and then their different influences on cytochrome P450 enzymes (CYPs) and UDP-glucuronyltransferases (UGTs) in L-02 cells were tested to explore the potential interaction and different bioactivities. Our results proved that curcumin could be metabolised into OHC stereoisomers first. In addition, Meso-OHC and (3S,5S)-OHC exhibited slight induction or inhibition effects on CYP1A2, CYP2A6, CYP2C8, CYP2C9, CYP3A4 and UGTs. Furthermore, Meso-OHC exhibited more intensive inhibition toward CYP2E1 expression than (3S,5S)-OHC, ascribed to the different mode of binding to the enzyme protein (P < 0.05), which finally induced more effective liver protection effects in acetaminophen-induced L-02 cell injury.

Effect of Clomethiazole Vs. Clorazepate on Hepatic Fat and Serum Transaminase Activities in Alcohol-Associated Liver Disease: Results from a Randomized, Controlled Phase II Clinical Trial

AIMS

Alcohol-associated liver disease (ALD) is a global health problem caused, among other factors, by oxidative stress from the formation of reactive oxygen species (ROS). One important source of ROS is microsomal ethanol metabolism catalyzed by cytochrome P450 2E1 (CYP2E1), which is induced by chronic ethanol consumption. Inhibition of CYP2E1 by clomethiazole (CMZ) decreases oxidative stress in cell cultures and improves ALD in animal studies. Our study aimed to assess the benefits of a CYP2E1 inhibitor (clomethiazole) in detoxification of patients with ALD.

METHODS

Open label, randomized controlled clinical trial to study whether CYP2E1 inhibition improves ALD in the patients with alcohol use disorders admitted for alcohol detoxification therapy (ADT). Patients had to have a serum aspartate aminotransferase (AST) activity exceeding twice the upper normal limit at time of admission and be non-cirrhotic defined by fibroscan value <12 kPa. Sixty patients were randomly assigned to ADT with either CMZ or clorazepate (CZP) for 7-10 days in a 1:1 ratio. The chlorzoxazone test of CYP2E1 activity was performed at enrolment and at 2 points during the study.

RESULTS

ADT improved hepatic steatosis (controlled attenuation parameter) in both groups significantly. A trend towards a greater improvement in hepatic fat content during ADT (-21.5%) was observed in the CMZ group (252 ± 48 dB/m vs. 321 ± 38 dB/m; P < 0.0001) compared with the CZP group (-13.9%; 273 ± 38 dB/m vs. 317 ± 39 dB/m; P < 0.0001). As already reported, serum AST (P < 0.004) and alanine aminotransferase (ALT) activities (P < 0.0006) significantly decreased in CMZ patients as compared with patients on CZP by the end of hospitalization. A significant correlation was found between AST (P = 0.023), ALT (P = 0.009), GGT (P = 0.039) and CAP.

CONCLUSION

This study demonstrates that CMZ improves clinical biomarkers for ALD in humans most likely due to its inhibitory effect on CYP2E1. Because of its addictive potential, CMZ can only be given for a short period of time and therefore other CYP2E1 inhibitors to treat ALD are needed.

Synergistic toxicity of ethanol and 2,4-dichlorophenoxyacetic acid enhances oxidant status, DNA damage, inflammation, and apoptosis in rats

Clarifying the interactions between substances as a result of exposure to multiple xenobiotics and determining the impacts on health are important from the toxicological point of view. Therefore, the aim of the study was to investigate the synergistic toxic effects of ethanol and 2,4-dichlorophenoxyacetic acid (2,4-D) in male albino rats. A total number of 28 Wistar male rats were divided into 4 groups (7/each), and 2,4-D (5 mg/kg) and ethanol (3 g/kg) were administered orally to rats for 60 days, either alone or in combination. Co-administration of ethanol and 2,4-D increased liver functional enzyme levels and lipid peroxidation in blood and tissues while decreased glutathione and antioxidant enzyme activities when compared to individual applications. Furthermore, co-administration of ethanol and 2,4-D caused DNA damage as well as the increase in apoptotic and proinflammatory cytokine gene expressions. Furthermore, histopathological examination of the tissues especially liver and kidney revealed that these two substances induced more serious damage. In conclusion, co-administration of ethanol and 2,4-D resulted in strong toxic effects on tissues (especially liver) with a synergistic interaction and give rise to serious toxicological drawbacks.

Galacto-Oligosaccharide Alleviates Alcohol-Induced Liver Injury by Inhibiting Oxidative Stress and Inflammation

Alcoholic liver disease (ALD) is a primary cause of mortality and morbidity worldwide. Oxidative stress and inflammation are important pathogenic factors contributing to ALD. We investigated the protective mechanism of galacto-oligosaccharide (GOS) against ALD through their antioxidant and anti-inflammatory activities by performing in vivo and in vitro experiments. Western blot and RT‒PCR results indicated that the expression of cytochrome P450 protein 2E1 (CYP2E1) in liver tissues and L02 cells was reduced in the GOS-treated mice compared with the model group. In addition, GOS prominently reduced the expression of Kelch-like ECH-associated protein 1 (Keap1), increased the expression of the nuclear factor erythroid-2-related factor 2 (Nrf2) and haem oxygenase-1 (HO-1) proteins, and enhanced the antioxidant capacity. In addition, GOS decreased inflammation by reducing inflammatory factor levels and inhibiting the mitogen-activated protein kinase (MAPK)/nuclear factor kappa B (NF-κB) pathway. Based on these results, GOS may be a prospective functional food for the prevention and treatment of ALD.

Insulin resistance enhances binge ethanol-induced liver injury through promoting oxidative stress and up-regulation CYP2E1

Alcoholic liver disease (ALD) has caused a serious burden on public and personal health in crowd with ethanol abuse. The effects of insulin resistance (IR) on ALD and the mechanisms underlying these responses are still not well understood. In this study, we investigated the changes of liver injury, inflammation, apoptosis, mitochondrial dysfunction and CYP2E1 changes in liver of mice exposed to ethanol with IR or not. We found IR increased the sensitivity of liver injury in mice exposed to ethanol, manifested as the increase serum activities of AST and ALT, the accumulation of triglycerides, the deterioration of liver pathology and increase of inflammatory factors. IR also exacerbated apoptosis and mitochondrial dysfunction in liver of mice exposed to ethanol. The increase of oxidative stress and the decrease of antioxidant defense ability might be responsible for the sensitizing effects of IR on ethanol-induced liver injury, supported by the increase of MDA levels and the decline of GSH/GSSG, the inactivation of antioxidant enzymes SOD, GR through the inhibition of Nrf-2 pathway. The activation of CYP2E1 might be also involved in the sensitizing effects of IR on ethanol induced liver injury in mice. These results demonstrated that IR exhibited a significant pro-oxidative and pro-apoptosis effects to aggravate alcoholic liver injury. Our study helped us to better understand the sensitive role of IR on ALD and suggested that alcohol intake may be more harmful for people with IR.

Diallyl disulfide ameliorates ethanol-induced liver steatosis and inflammation by maintaining the fatty acid catabolism and regulating the gut-liver axis

Diallyl disulfide (DADS) has been suggested to possess hepatoprotection against alcoholic liver disease (ALD) by a couple of pilot studies, while the underlying mechanisms remain largely unknown. This study aimed to investigate the hepatoprotective effects of DADS against ethanol-induced liver steatosis and early inflammation by using the chronic-plus-binge mice model and cultured J774A.1 macrophages and AML12 hepatocytes. We found that DADS significantly attenuated ethanol-induced elevation of serum aminotransferase activities, accumulation of liver triglyceride, hepatocytes apoptosis, oxidative stress, infiltration of macrophages and neutrophils, and proinflammatory polarization of macrophages in mice livers. In addition, chronic-plus-binge drinking induced apparent intestinal mucosa damage and disturbance of gut microbiota, endotoxemia, and activation of hepatic NF-κB signaling and NLRP3 inflammasome, which was inhibited by DADS. In vitro studies using cocultured AML12/J774A.1 cells showed that DADS suppressed ethanol/LPS-induced cell injury and inflammatory activation of macrophages. Furthermore, DADS ameliorated ethanol-induced decline of peroxisome proliferator-activated receptor α (PPARα), carnitine palmitoyltransferase 1 (CPT1), and phosphorylated AMP-activated protein kinase (AMPK) protein levels in mice liver and AML12 cells. These results demonstrate that DADS could prevent ethanol-induced liver steatosis and early inflammation by regulating the gut-liver axis and maintaining fatty acid catabolism.

CYP2E1 plays a suppressive role in hepatocellular carcinoma by regulating Wnt/Dvl2/β-catenin signaling

Objective

Knowledge of the role of CYP2E1 in hepatocarcinogenesis is largely based on epidemiological and animal studies, with a primary focus on the role of CYP2E1 in metabolic activation of procarcinogens. Few studies have directly assessed the effects of CYP2E1 on HCC malignant phenotypes.

Methods

The expression of CYP2E1 in HCC tissues was determined by qRT-PCR, western blotting and immunohistochemistry. Overexpression of CYP2E1 in HCC cell was achieved by lentivirus transfection. The function of CYP2E1 were detected by CCK-8, wound healing, transwell assays, xenograft models and pulmonary metastasis model. TOP/FOPFlash reporter assay, western blotting, functional rescue experiments, Co-immunoprecipitation and reactive oxygen species detection were conducted to reveal the underlying mechanism of the tumor suppressive role of CYP2E1.

Results

CYP2E1 expression is down-regulated in HCC tissues, and this downregulation was associated with large tumor diameter, vascular invasion, poor differentiation, and shortened patient survival time. Ectopic expression of CYP2E1 inhibits the proliferation, invasion and migration and epithelial-to-mesenchymal transition of HCC cells in vitro, and inhibits tumor formation and lung metastasis in nude mice. Mechanistic investigations show that CYP2E1 overexpression significantly inhibited Wnt/β-catenin signaling activity and decreased Dvl2 expression in HCC cells. An increase in Dvl2 expression restored the malignant phenotype of HCC cells. Notably, CYP2E1 promoted the ubiquitin-mediated degradation of Dvl2 by strengthening the interaction between Dvl2 and the E3 ubiquitin ligase KLHL12 in CYP2E1-stable HCC cells. CYP2E1-induced ROS accumulation was a critical upstream event in the Wnt/β-Catenin pathway in CYP2E1-overexpressing HCC cells.

Conclusions

These results provide novel insight into the role of CYP2E1 in HCC and the tumor suppressor role of CYP2E1 can be attributed to its ability to manipulate Wnt/Dvl2/β-catenin pathway via inducing ROS accumulation, which provides a potential target for the prevention and treatment of HCC.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03396-6.

Fermented Curcuma longa L. Prevents Alcoholic Fatty Liver Disease in Mice by Regulating CYP2E1, SREBP-1c, and PPAR-α

We examined the efficacy of fermented Curcuma longa L. (FT) on the development of alcoholic fatty liver in mice and investigated the underlying mechanism. The protective potential of FT against ethanol-induced fatty liver was determined using C57BL/6 male mice allocated into four groups (8 mice/group). Control groups received either distilled water or 5 g/kg body weight (b.w.) per day ethanol for 8 days. Treatment groups were administered either 300 mg/kg b.w. per day of milk thistle or FT before receiving ethanol. FT contained a higher amount of caffeic acid and tetrahydrocurcumin than C. longa. FT pretreatment significantly suppressed the elevated hepatic lipid droplets associated with ethanol ingestion. In comparison with ethanol-treated control, FT pretreated mice showed inhibited cytochrome P4502E1 (CYP2E1), sterol regulatory element-binding protein-1 (SREBP-1c), and acetyl-CoA carboxylase production but elevated AMP-activated protein kinase, peroxisome proliferator-activated receptor-alpha (PPAR-α), and carnitine palmitoyltransferase 1 (CPT-1) levels. Taken together, FT is a promising hepatoprotectant for preventing of alcoholic fatty liver through modulating fatty acid synthesis and oxidation.

Prenatal ethanol exposure induces dynamic changes of expression and activity of hepatic cytochrome P450 isoforms in male rat offspring

This study aimed at determining the effect of prenatal ethanol exposure (PEE) on the expression and activity of cytochrome P450 (CYP) isozymes at different life stages of male rat offspring. Pregnant Wistar rats were administered with ethanol (4 g/kg/d) intragastrically from gestational day (GD) 9-20. Male offspring's gene and activity of CYP isozymes were analyzed on GD 20 (only expression), postnatal day (PD) 84 and 196. Using aniline as probe, we compared the enzyme kinetics of hepatic CYP2E1 between two groups. Expression of CYP isozymes was examined in rat primary hepatocytes and human hepatic cell lines treated with ethanol or/and glucocorticoid. Gene level of Cyp1a2, 2b1, 2d1, 2e1, 3a1 and aryl hydrocarbon receptor were increased in PEE group on GD 20 and PD 84 and Cyp2e1 still exhibited an increasing trend on PD 196 compared with the control. PEE inhibited CYP2D1 and 2E1 activities in male offspring on PD 84. CYP activities in two groups became the same level on PD 196. PEE induced an opposite change in gene and protein level of hepatic CYP2E1 before and after birth. In consistent with lower protein level, aniline metabolism in PEE was weaker in liver microsome. Both single and combined use of ethanol or/and glucocorticoid increased CYPs expression in vitro. In conclusion, PEE programmed a higher gene and lower protein level of CYPs in male offspring, which dwindled with age. Impairment of protein levels and enzyme activities of CYPs may affect individual metabolism of endogenous and exogenous substances in early adulthood.

Neuroprotective Effects of Crocin Against Ethanol Neurotoxicity in the Animal Model of Fetal Alcohol Spectrum Disorders

Several experimental and clinical findings suggest that ethanol consumption during pregnancy activates an oxidative-inflammatory cascade followed by wide apoptotic neurodegeneration within several brain areas, including the hippocampus. Crocin can protect neurons because of its antioxidant, anti-inflammatory, and antiapoptotic effects. This study evaluated the crocin protective impact on ethanol-related neuroinflammation and neuronal apoptosis in the hippocampus of rat pups exposed to alcohol over postnatal days. Ethanol (5.25 g/kg) was administrated in milk solution (27.8 ml/kg) by intragastric intubation 2-10 days after birth. The animals received crocin (15, 30, and 45 mg/kg) 2-10 days after birth. The hippocampus-dependent memory and spatial learning were evaluated 36 days after birth using the Morris water maze task. Further, the concentrations of TNF-α and antioxidant enzymes were determined using ELISA assay to examine the antioxidant and anti-inflammatory activities. Also, immunohistochemical staining was performed to evaluate the glial fibrillary acidic protein (GFAP), Ionized calcium binding adaptor molecule 1(Iba-1), and caspase-3 expression. The administration of crocin significantly attenuated spatial memory impairment (P < 0.01) after ethanol neurotoxicity. Also, crocin led to a significant enhancement in SOD (P < 0.05) and GSH-PX (P < 0.01), whereas it caused a reduction in the TNF-α and MDA concentrations compared to the ethanol group (P < 0.01). Moreover, the hippocampal level of caspase-3 (P < 0.01) and the number of GFAP and Iba-1-positive cells decreased in the crocin group (P < 0.001). Crocin suppresses apoptotic signaling mediated by the oxidative-inflammatory cascade in rat pups exposed to ethanol after birth.

Triptolide regulates oxidative stress and inflammation leading to hepatotoxicity via inducing CYP2E1

Triptolide (TP), the main active compound extracted from medicine-tripterygium wilfordii Hook f. (TWHF). It has anti-tumor and immunomodulatory properties. Our study aimed to investigate the mechanisms of hepatotoxicity treated with TP in vivo and in vitro, as well as their relationship with the NF-κB (p65) signal pathway; and to assess TP-induced hepatotoxicity after CYP2E1 modulation by the known inhibitor, clomethiazole, and the known inducer, pyrazole. Mice were given TP to cause liver injury and IHHA-1 cells were given TP to cause hepatocyte injury. The enzyme activity and hepatotoxicity changed dramatically when the CYP2E1 inhibitor and inducer were added. In comparison to the control group, the enzyme inducer increased the activity of CYP2E1, whereas the enzyme inhibitor had the opposite effect. Our findings suggest that TP is an inducer of CYP2E1 via a time-dependent activation mechanism. In addition, TP can promote oxidative stress, inflammatory and involving the NF-κB (p65) signal pathway. Therefore, we used triptolide to stimulate C57 mice and IHHA-1 cells to determine whether TP can promote oxidative stress and inflammation by activating CYP2E1 in response to exacerbated liver damage and participate in NF-κB (p65) signaling pathway.

Targeting Peroxisome Proliferator-Activated Receptor-β/δ (PPARβ/δ) for the Treatment or Prevention of Alcoholic Liver Disease

Excessive, chronic alcohol consumption can lead to alcoholic liver disease. The etiology of alcoholic liver disease is multifactorial and is influenced by alterations in gene expression and changes in fatty acid metabolism, oxidative stress, and insulin resistance. These events can lead to steatosis, fibrosis, and eventually to cirrhosis and liver cancer. Many of these functions are regulated by peroxisome proliferator-activated receptors (PPARs). Thus, it is not surprising that PPARs can modulate the mechanisms that cause alcoholic liver disease. While the roles of PPARα and PPARγ are clearer, the role of PPARβ/δ in alcoholic liver disease requires further clarification. This review summarizes the current understanding based on recent studies that indicate that PPARβ/δ can likely be targeted for the treatment and/or the prevention of alcoholic liver disease.

Nebivolol alleviates liver damage caused by methotrexate via AKT1/Hif1α/eNOS signaling

Despite the wide clinical indications, methotrexate (MTX) use is limited because of serious side effects including liver toxicity. MTX was shown to cause tissue damage by mainly oxidative stress and also inflammation and apoptosis. Thus, Nebivolol (NEB) which has antioxidant and antiapoptotic properties were thought to be effective against MTX-induced injury. This study aimed to evaluate the effects of NEB on MTX-induced liver toxicity via AKT/Hypoxia-Inducible Factor 1 Alpha (HIF1α)/Endothelial Nitric Oxide Synthase (eNOS) signaling pathways. Rats were divided into three groups as control, MTX, and NEB. A single dose of MTX (20 mg/kg intraperitoneally) was given to the rats on the first day of the experiment and NEB (10 mg/kg, daily by oral gavage) was given to the treatment group for a week. At the end of the experiment, bloods were taken for aspartate transaminase (AST), alanine aminotransferase (ALT), and total bilirubin (T-BIL) analyses. Liver tissues were harvested for biochemical (total oxidant status (TOS) and total antioxidant status (TAS), genetic (PCR analyses for AKT1, eNOS, and HIF1a), and histological (Hemotoxylin-Eosin, Masson Trichome, Periodic Acid Schiff-Asien Blue, reticulin for histological, and CD3 for immunohistochemical staining) analyses. MTX increased the levels of TOS values, AST, ALT, T-BIL levels and decreased the expressions of AKT/HIF1α/eNOS. NEB treatment reversed all these changes markedly via decreasing inflammation by nitric oxid (NO) production. In conclusion, NEB treatment significantly preserves the liver by decreasing oxidant levels and inflammatory parameters through HIF1α/eNOS signaling. Due to the antioxidant properties of NEB, it can be used in other liver injury models sharing the same pathway.

TA allele of rs2070673 in the CYP2E1 gene is associated with lobular inflammation and nonalcoholic steatohepatitis in patients with biopsy-proven nonalcoholic fatty liver disease

BACKGROUND AND AIM

Cytochrome P450 2E1 (CYP2E1) plays a role in lipid metabolism, and by increasing hepatic oxidative stress and inflammation, the upregulation of CYP2E1 is involved in development of nonalcoholic steatohepatitis (NASH). We aimed to explore the relationship between CYP2E1-333A>T (rs2070673) and the histological severity of nonalcoholic fatty liver disease (NAFLD).

METHODS

We studied 438 patients with biopsy-proven NAFLD. NASH was defined as NAFLD Activity Score ≥ 5 with existence of steatosis, ballooning, and lobular inflammation. CYP2E1-333A>T (rs2070673) was genotyped by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Serum cytokines related to inflammation were measured by the Bio-plex 200 system to investigate possible mediating factors involved in the process.

RESULTS

The TA genotype of rs2070673 had a higher prevalence of moderate/severe lobular inflammation (27.6% vs 20.3% vs 13.3%, P < 0.01) and NASH (55.7% vs 42.4% vs 40.5%, P < 0.01) compared with the AA and TT genotypes, respectively. In multivariable regression modeling, the heterozygote state TA was associated with moderate/severe lobular inflammation (adjusted odds ratio: 2.31, 95% confidence interval 1.41-3.78, P < 0.01) or NASH (adjusted odds ratio: 1.82, 95% confidence interval 1.22-2.69, P < 0.01), independently of age, sex, common metabolic risk factors, and presence of liver fibrosis. Compared with no-NASH, NASH patients had significantly higher levels of serum interleukin-1 receptor antagonist, interleukin-18, and interferon-inducible protein-10 (IP-10), whereas only IP-10 was increased with the rs2070673 TA variant (P = 0.01). Mediation analysis showed that IP-10 was responsible for ~60% of the association between the rs2070672 and NASH.

CONCLUSIONS

The TA allele of rs2070673 is strongly associated with lobular inflammation and NASH, and this effect appears to be largely mediated by serum IP-10 levels.

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

BACKGROUND

Alcoholic liver disease (ALD) is a progressive disease beginning with simple steatosis but can progress to alcoholic steatohepatitis, fibrosis, cirrhosis, and even hepatocellular carcinoma. The morbidity of ALD is on the rise and has been a large burden on global healthcare system. It is unfortunately that there are currently no approved therapeutic drugs against ALD. Hence, it is of utmost urgency to develop the efficacious therapies. The ability of many molecular targets against ALD is under investigation. Farnesoid X receptor (FXR), a member of the ligand-activated transcription factor superfamily, has been recently demonstrated to have a crucial role in the pathogenesis and progression of ALD.

PURPOSE

The purpose of the study is to determine whether Yangonin (YAN), a FXR agonist previously demonstrated by us, exerts the hepatoprotective effects against ALD and further to clarify the mechanisms in vitro and in vivo.

STUDY DESIGN

The alcoholic liver disease model induced by Lieber-Decarli liquid diet was established with or without Yan treatment.

METHODS

We determined the liver to body weight ratios, the body weight, serum and hepatic biochemical indicators. The alleviation of the liver histopathological progression was evaluated by H&E and immunohistochemical staining. Western blot and quantitative real-time PCR were used to demonstrate YAN treatment-mediated alleviation mechanisms of ALD.

RESULTS

The data indicated that YAN existed hepatoprotective activity against ALD via FXR activation. YAN improved the lipid homeostasis by decreasing hepatic lipogenesis and increasing fatty acid β-oxidation and lipoprotein lipolysis through modulating the related protein. Also, YAN ameliorated ethanol-induced cholestasis via inhibiting bile acid uptake transporter Ntcp and inducing bile acid efflux transporter Bsep and Mrp2 expression. Besides, YAN improved bile acid homeostasis via inducing Sult2a1 expression and inhibiting Cyp7a1 and Cyp8b1 expression. Furthermore, YAN attenuated ethanol-triggered hepatocyte damage by inhibiting cellular senescence marker P16, P21 and Hmga1 expression. Also, YAN alleviated ethanol-induced inflammation by down-regulating the inflammation-related gene IL-6, IL-1β and TNF-α expression. Notably, the protective effects of YAN were cancelled by FXR siRNA in vitro and FXR antagonist GS in vivo.

CONCLUSIONS

YAN exerted significant hepatoprotective effects against liver injury triggered by ethanol via FXR-mediated target gene modulation.

Polymorphisms in genes related to oxidative stress and inflammation: Emerging links with the pathogenesis and severity of Cerebral Cavernous Malformation disease

Cerebral Cavernous Malformation (CCM) is a cerebrovascular disease of genetic origin affecting 0.5% of the population and characterized by abnormally enlarged and leaky capillaries that predispose to seizures, neurological deficits, and intracerebral hemorrhage (ICH). CCM occurs sporadically or is inherited as dominant condition with incomplete penetrance and highly variable expressivity. Three disease genes have been identified: KRIT1 (CCM1), CCM2 and CCM3. Previous results demonstrated that loss-of-function mutations of CCM genes cause pleiotropic effects, including defective autophagy, altered reactive oxygen species (ROS) homeostasis, and enhanced sensitivity to oxidative stress and inflammatory events, suggesting a novel unifying pathogenetic mechanism, and raising the possibility that CCM disease onset and severity are influenced by the presence of susceptibility and modifier genes. Consistently, genome-wide association studies (GWAS) in large and homogeneous cohorts of patients sharing the familial form of CCM disease and identical mutations in CCM genes have led to the discovery of distinct genetic modifiers of major disease severity phenotypes, such as development of numerous and large CCM lesions, and susceptibility to ICH. This review deals with the identification of genetic modifiers with a significant impact on inter-individual variability in CCM disease onset and severity, including highly polymorphic genes involved in oxidative stress, inflammatory and immune responses, such as cytochrome P450 monooxygenases (CYP), matrix metalloproteinases (MMP), and Toll-like receptors (TLR), pointing to their emerging prognostic value, and opening up new perspectives for risk stratification and personalized medicine strategies.

Ferulic acid prevents aflatoxin B1-induced liver injury in rats via inhibiting cytochrome P450 enzyme, activating Nrf2/GST pathway and regulating mitochondrial pathway

Aflatoxin B1 (AFB1) causes oxidative stress and hepatocyte apoptosis through its epoxidized metabolite AFBO, which is catalyzed by CYP450 enzymes. Ferulic acid (FA) is a phenolic acid commonly found in plants and is known for its antioxidant capacity. However, the role of FA in AFB1-induced liver injury is still elusive. In this study, rats were exposed to AFB1 and simultaneously treated with FA for 30 days. The results showed that I) FA alleviated the histopathological changes induced by AFB1, inhibited the elevation of serological indexes induced by AFB1, and reduced the production of AFBO in liver. II) AFB1-induced increase in CYP450 expression was significantly reduced by FA. The molecular docking results of FA and CYP2A6 showed high fitness score and interaction. III) FA obviously inhibited the production of MDA, and significantly activated the Nrf2/GST pathway and antioxidant enzymes (SOD and GST). IV) AFB1-induced hepatocyte apoptosis, the high expression of p53, bax, cyt-c, caspase-9, caspase-3, and the low expression of bcl-2 were all restored by FA. It has been suggested from these results that FA proved effective against AFB1-induced liver damage in rats via inhibiting CYP450 enzyme, promoting antioxidant pathway Nrf2/GST, activating antioxidant enzymes (SOD and GST), and regulating the mitochondrial pathway.

Oxidative Stress-A Key Player in the Course of Alcohol-Related Liver Disease

Oxidative stress is known to be an inseparable factor involved in the presentation of liver disorders. Free radicals interfere with DNA, proteins, and lipids, which are crucial in liver metabolism, changing their expression and biological functions. Additionally, oxidative stress modifies the function of micro-RNAs, impairing the metabolism of hepatocytes. Free radicals have also been proven to influence the function of certain transcriptional factors and to alter the cell cycle. The pathological appearance of alcohol-related liver disease (ALD) constitutes an ideal example of harmful effects due to the redox state. Finally, ethanol-induced toxicity and overproduction of free radicals provoke irreversible changes within liver parenchyma. Understanding the underlying mechanisms associated with the redox state in the course of ALD creates new possibilities of treatment for patients. The future of hepatology may become directly dependent on the effective action against reactive oxygen species. This review summarizes current data on the redox state in the natural history of ALD, highlighting the newest reports on this topic.

Demethylenetetrahydroberberine alleviates nonalcoholic fatty liver disease by inhibiting the NLRP3 inflammasome and oxidative stress in mice

AIMS

Demethylenetetrahydroberberine (DMTHB) is a novel derivative of berberine and demethyleneberberine. This research explored the pharmacological effects and molecular mechanisms of DMTHB on nonalcoholic fatty liver disease (NAFLD).

MATERIALS AND METHODS

C57BL/6 mice were induced by a methionine- and choline- deficient (MCD) diet and L02 cells were induced by palmitic acid to establish NAFLD animal and cell models. qPCR and western blotting were used to detect the expression of genes and proteins associated with pharmacological mechanism. A biotin-labeled DMTHB pulldown assay was used to further clarify the pharmacological targets.

KEY FINDINGS

Our results indicated that DMTHB significantly alleviates NAFLD in mice. Biochemical assays showed that serum alanine aminotransferase, aspartate aminotransferase and hepatic lipids were significantly decreased in MCD-induced NAFLD mice orally administered of DMTHB (50 mg/kg or 150 mg/kg body weight daily) for 30 d. qPCR and ELISA analysis demonstrated that DMTHB reduced the expression of serum proinflammatory cytokines, such as TNF-α, IL-1β and IL-6. Moreover, pull-down assays and compound-centric chemical proteomics illustrated that DMTHB inhibited NOD-like receptor protein 3 (NLRP3) inflammasome signaling. In addition, DMTHB also attenuated oxidative stress and endoplasmic reticulum stress by downregulation CYP2E-1 and ATF-4 expression. Moreover, DMTHB treatment ameliorated the liver fibrosis in MCD-induced NAFLD mice by suppressing the expression of TGF-β1, α-SMA and collagen 1A1.

SIGNIFICANCE

DMTHB targeted the NLRP3 inflammasome to suppress inflammation and inhibited CYP2E1 to reduce oxidative stress and ER stress. Consequently, DMTHB may have therapeutic benefits in the treatment of NAFLD in the clinic.

A mini-review of the rodent models for alcoholic liver disease: shortcomings, application, and future prospects

Rodents are the most common models in studies of alcoholic liver disease (ALD). Although several rodents ALD models have been established and multiple mechanisms have been elucidated based on them, these models have some non-negligible shortcomings, specifically only inducing early stage (mainly steatosis, slight to moderate steatohepatitis) but not the whole spectrum of human ALD. The resistance of rodents to advanced ALD has been suggested to be due to the physiological differences between rodents and human beings. Previous studies have reported significant interstrain differences in the susceptibility to ethanol-induced liver injury and in the manifestation of ALD (such as different alteration of lipid profiles). Therefore, it would be interesting to characterize the manifestation of ethanol-induced liver damage in various rodents, which may provide a recommendation to investigators of ALD. Furthermore, more severe ALD models need to be established for the study of serious ALD forms, which may be achieved by using genetic modified rodents.

S-Allylmercaptocysteine improves alcoholic liver disease partly through a direct modulation of insulin receptor signaling

Alcoholic liver disease (ALD) causes insulin resistance, lipid metabolism dysfunction, and inflammation. We investigated the protective effects and direct regulating target of S-allylmercaptocysteine (SAMC) from aged garlic on liver cell injury. A chronic ethanol-fed ALD in vivo model (the NIAAA model) was used to test the protective functions of SAMC. It was observed that SAMC (300 mg/kg, by gavage method) effectively ameliorated ALD-induced body weight reduction, steatosis, insulin resistance, and inflammation without affecting the health status of the control mice, as demonstrated by histological, biochemical, and molecular biology assays. By using biophysical assays and molecular docking, we demonstrated that SAMC directly targeted insulin receptor (INSR) protein on the cell membrane and then restored downstream IRS-1/AKT/GSK3β signaling. Liver-specific knock-down in mice and siRNA-mediated knock-down in AML-12 cells of Insr significantly impaired SAMC (250 μmol/L in cells)-mediated protection. Restoration of the IRS-1/AKT signaling partly recovered hepatic injury and further contributed to SAMC's beneficial effects. Continuous administration of AKT agonist and recombinant IGF-1 in combination with SAMC showed hepato-protection in the mice model. Long-term (90-day) administration of SAMC had no obvious adverse effect on healthy mice. We conclude that SAMC is an effective and safe hepato-protective complimentary agent against ALD partly through the direct binding of INSR and partial regulation of the IRS-1/AKT/GSK3β pathway.

Simvastatin attenuates spatial memory impairment via inhibiting microgliosis and apoptotic cell death against ethanol induced neurotoxicity in the developing rat hippocampus

Ethanol is associated with oxidative stress. Exposure to ethanol during childhood may lead to neurological disorders. Congenital disorders induced by alcohol are mainly caused by an oxidative-inflammatory cascade due to extensive apoptotic neurodegeneration in the brain, particularly in the hippocampus. Simvastatin, which acts as an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA), is widely used to manage cardiovascular diseases. Recently, the neuroprotective effects of simvastatin against nervous system disorders have been introduced. In this study, we examined the protective effects of simvastatin on ethanol-related neurotoxicity in the hippocampus of rat pups. Ethanol (5.27 g/kg) in a milk solution (27.8 mL/kg) was administered to male rat pups via intragastric intubation at 2-10 days after birth. Also, 10 and 20 mg/kg of simvastatin were injected to the animals. By using Morris water maze task, the hippocampus-dependent memory and spatial learning was evaluated 36 days after birth. An ELISA assay was performed to investigate the antioxidant and anti-inflammatory effects of simvastatin by measuring the levels of tumor necrosis factor-α (TNF-α), and antioxidant enzymes. To assess the expression levels of Iba1 immunohistochemical staining and caspase-3 immunofluorescence staining was performed. The current study demonstrated that administration of simvastatin significantly attenuates spatial memory impairment (P < 0.01) after ethanol neurotoxicity. Also simvastatin could considerably increase the total superoxide dismutaseand glutathione levels (P < 0.01). Moreover, it was associated with a greater reduction in malondialdehyde (P < 0.05) and TNF-α levels, compared to the ethanol group (P < 0.01). Furthermore, in the simvastatin group, the hippocampal level of caspase-3 and the level of Iba1-positive cells, reduced (P < 0.01). This study demonstrated that apoptotic signaling, mediated by the oxidative-inflammatory cascade, could be inhibited by simvastatin in rat pups with ethanol exposure in the postnatal period.

A New CYP2E1 Inhibitor, 12-Imidazolyl-1-dodecanol, Represents a Potential Treatment for Hepatocellular Carcinoma

Cytochrome P450 2E1 (CYP2E1) is a key target protein in the development of alcoholic and nonalcoholic fatty liver disease (FLD). The pathophysiological correlate is the massive production of reactive oxygen species. The role of CYP2E1 in the development of hepatocellular carcinoma (HCC), the final complication of FLD, remains controversial. Specifically, CYP2E1 has not yet been defined as a molecular target for HCC therapy. In addition, a CYP2E1-specific drug has not been developed. We have already shown that our newly developed CYP2E1 inhibitor 12-imidazolyl-1-dodecanol (I-ol) was therapeutically effective against alcoholic and nonalcoholic steatohepatitis. In this study, we investigated the effect of I-ol on HCC tumorigenesis and whether I-ol could serve as a possible treatment option for terminal-stage FLD. I-ol exerted a very highly significant antitumour effect against hepatocellular HepG2 cells. Cell viability was reduced in a dose-dependent manner, with only the highest doses causing a cytotoxic effect associated with caspase 3/7 activation. Comparable results were obtained for the model colorectal adenocarcinoma cell line, DLD-1, whose tumorigenesis is also associated with CYP2E1. Transcriptome analyses showed a clear effect of I-ol on apoptosis and cell-cycle regulation, with the increased expression of p27Kip1 being particularly noticeable. These observations were confirmed at the protein level for HepG2 and DLD-1 cells grafted on a chorioallantoic membrane. Cell-cycle analysis showed a complete loss of proliferating cells with a simultaneous increase in S-phase arrest beginning at a threshold dose of 30 μM. I-ol also reduced xenograft tumour growth in nude mice. This antitumour effect was not associated with tumour cachexia. I-ol was not toxic to healthy tissues or organs. This study demonstrates for the first time the therapeutic effect of the specific CYP2E1 inhibitor I-ol on the tumorigenesis of HCC. Our findings imply that I-ol can potentially be applied therapeutically on patients at the final stage of FLD.

Alcohol suppresses cardiovascular diurnal variations in male normotensive rats: Role of reduced PER2 expression and CYP2E1 hyperactivity in the heart

BACKGROUND AND AIMS

The molecular mechanism of the adverse effects of ethanol on diurnal cardiovascular regulation remains unknown. In separate studies, the cardiac circadian rhythm protein period-2 (PER2) confers cardioprotection and, in other organs, PER2 interaction with the ethanol-metabolizing enzyme CYP2E1 underlies, via heme oxygenase-1 (HO-1) upregulation, tissue injury/dysfunction. Here, we hypothesized that suppressed PER2 expression and elevated CYP2E1/HO-1 levels in the heart underlie the disrupted diurnal cardiovascular rhythm/function in alcohol-fed normotensive rats.

METHODS

In ethanol-fed (5%, w/v; 8 weeks) or isocaloric liquid diet-fed male rats, diurnal changes in blood pressure (BP), heart rate (HR), HR vagal variability index, root mean square of successive beat-to-beat differences in beat-interval duration (rMSSD), and cardiac function were measured by radiotelemetry and echocardiography followed by ex vivo molecular studies.

RESULTS

Radiotelemetry findings showed ethanol-evoked reductions in BP (during the dark cycle), rMSSD (during both cycles), and in diurnal differences in BP and rMSSD. Echocardiography findings revealed significant (p < 0.05) reductions in ejection fraction and fractional shortening (weeks 4-6) in the absence of cardiac remodeling (collagen content). Hearts of ethanol-fed rats exhibited higher (p < 0.05) CYP2E1 activity (50%) and HO-1 expression (63%), along with reduction (p < 0.05) in PER2 levels (29%), compared with the hearts of isocaloric diet-fed control rats.

CONCLUSIONS

Our novel findings implicate upregulations of CYP2E1/HO-1 and downregulation of the circadian rhythm cardioprotective protein PER2, in the heart, in the chronic deleterious diurnal cardiovascular effects of alcohol in male rats.

Ethanol-induced CYP2E1 Expression is Reduced by Lauric Acid via PI3K Pathway in HepG2 Cells

The metabolism of alcohol involves cytochrome P450 2E1 (CYP2E1)-induced oxidative stress, with the association of phosphatidylinositol-3-kinases (PI3K) and nuclear factor kappa B (NFκB) signalling pathways. CYP2E1 is primarily involved in the microsomal ethanol oxidising system, which generates massive reactive oxygen species (ROS) and ultimately leads to oxidative stress and tissue damage. Lauric acid, a major fatty acid in palm kernel oil, has been shown as a potential antioxidant. Here, we aimed to evaluate the use of lauric acid as a potential antioxidant against ethanol-mediated oxidative stress by investigating its effect on CYP2E1 mRNA expression and the signalling pathway in ethanol-induced HepG2 cells. HepG2 cells were firstly treated with different concentrations of ethanol, and subsequently co-treated with different concentrations of lauric acid for 24 h. Total cellular RNA and total protein were extracted, and qPCR and Western blot was carried out. Ethanol induced the mRNA expression of CYP2E1 significantly, but lauric acid was able to downregulate the induced CYP2E1 expression in a dose-dependent manner. Similarly, Western blot analysis and densitometry analysis showed that the phosphorylated PI3K p85 (Tyr458) protein was significantly elevated in ethanol-treated HepG2 cells, but co-treatment with lauric acid repressed the activation of PI3K. However, there was no significant difference in NFκB pathway, in which the normalised NFκB p105 (Ser933) phosphorylation remained constant in any treatment conditions in this study. This suggests that ethanol induced CYP2E1 expression by activating PI3K p85 (Tyr458) pathway, but not the NFκB p105 (Ser933) pathway in HepG2 cells.

Effects of taraxasterol against ethanol and high-fat diet-induced liver injury by regulating TLR4/MyD88/NF-κB and Nrf2/HO-1 signaling pathways

Studies have reported that taraxasterol (TAR) is effective in the treatment of immune liver injury and alcoholic liver injury. The mechanism of action is mainly related to the inhibition of inflammation. To determine the key molecular mechanisms for the effect of TAR on alleviating ethanol and high-fat diet-induced liver injury, pathological morphology, biochemistry, oxidative stress, inflammatory response and lipid metabolism were examined. Our results showed that TAR could inhibit ethanol-induced hepatocyte death or lipid accumulation, and suppress oxidative stress, inflammatory response and lipid metabolism disorders. More specifically, ethanol-induced TLR-4 and MyD88 inflammatory response were down-regulated, when treated with TAR. Production of CYP2E1, Nrf2 and HO-1, which produced in response to increased oxidative stress, were regulated in TAR treated, ethanol-induced hepatocytes. In summary, TAR could inhibit the inflammatory response and oxidative stress, which was related to the regulation of TAR on TLR-4/MyD88/NF-κB and Nrf2/HO-1 pathways.

Involvement of CYP2E1-ROS-CD36/DGAT2 axis in the pathogenesis of VPA-induced hepatic steatosis in vivo and in vitro

Valproic acid (VPA) is a widely prescribed antiepileptic drug, which may cause steatosis in the liver. Oxidative stress is associated with the progression of VPA-induced hepatic steatosis. However, the potential mechanisms are not fully understood. In this study, we demonstrated the involvement of CYP2E1-ROS-CD36/DGAT2 axis in the pathogenesis of VPA-induced hepatic steatosis in vitro and in vivo. First, VPA treatment (500 mg/kg in mice, 5 mM in LO₂ cells) induced hepatic steatosis and enhanced reactive oxidative stress (ROS) level, and ROS scavenger, N-acetyl-L-cysteine (NAC, 200 mg/kg in mice, 1 mM in LO₂ cells) reversed the changes. Next, we observed the enhanced expression and enzymatic activity of cytochrome P450 2E1 (CYP2E1) in VPA-treated mice and LO₂ cells. Importantly, VPA-induced ROS accumulation and hepatic steatosis were attenuated when CYP2E1 was inhibited using CYP2E1 inhibitor, diallyl sulfide (DAS, 100 mg/kg in mice, 1 mM in LO₂ cells) or in CYP2E1-knockdown cell line, suggesting that CYP2E1 plays a potential role in ROS production following hepatic steatosis. Furthermore, gene expression analysis showed that the mRNA levels of cluster of differentiation 36 (CD36), a fatty acid translocase protein and distinct diacylglycerol acyltransferase 2 (DGAT2) were significantly upregulated in mice and LO₂ cells after VPA treatment, while the change was alleviated by NAC and DAS. Meanwhile, time course experiments demonstrated that the increase of CYP2E1 level occurred earlier than that of ROS, CD36 and DGAT2, and ROS generation preceded the onset of hepatic steatosis. Taken together, VPA treatment enhances the expression and enzymatic activity of CYP2E1, which promotes ROS production and then causes CD36 and DGAT2 overproduction and hepatic steatosis in mice and LO₂ cells, which provides a novel insight into VPA-induced hepatic steatosis.

An Overview of the Mechanism of Penthorum chinense Pursh on Alcoholic Fatty Liver

Alcohol liver disease (ALD) caused by excessive alcohol consumption is a progressive disease, and alcohol fatty liver disease is the primary stage. Currently, there is no approved drug for its treatment. Abstinence is the best way to heal, but patients' compliance is poor. Unlike other chronic diseases, alcohol fatty liver disease is not caused by nutritional deficiencies; it is caused by the molecular action of ingested alcohol and its metabolites. More and more studies have shown the potential of Penthorum chinense Pursh (PCP) in the clinical use of alcohol fatty liver treatment. The purpose of this paper is to reveal from the essence of PCP treatment of alcohol liver mechanism mainly by the ethanol dehydrogenase (ADH) and microsomal ethanol oxidation system-dependent cytochrome P4502E1 (CYP2E1) to exert antilipogenesis, antioxidant, anti-inflammatory, antiapoptotic, and autophagy effects, with special emphasis on its mechanisms related to SIRT1/AMPK, KEAP-1/Nrf2, and TLR4/NF-κB. Overall, data from the literature shows that PCP appears to be a promising hepatoprotective traditional Chinese medicine (TCM).

Roles of peroxisome proliferator-activated receptor α in the pathogenesis of ethanol-induced liver disease

Alcoholic liver disease (ALD) is a progressively aggravated liver disease with high incidence in alcoholics. Ethanol-induced fat accumulation and the subsequent lipopolysaccharide (LPS)-driven inflammation bring liver from reversible steatosis, to irreversible hepatitis, fibrosis, cirrhosis, and even hepatocellular carcinoma. Peroxisome proliferator-activated receptor α (PPARα) is a member of the nuclear receptor superfamily of ligand-activated transcription factors and plays pivotal roles in the regulation of fatty acid homeostasis as well as the inflammation control in the liver. It has been well documented that PPARα activity and/or expression are downregulated in liver of mice exposed to ethanol, which is thought to be one of the prime contributors to ethanol-induced steatosis, hepatitis and fibrosis. This article summarizes the current evidences from in vitro and animal models for the critical roles of PPARα in the onset and progression of ALD. Importantly, it should be noted that the expression of PPARα in human liver is reported to be similar to that in mice, and PPARα expression is downregulated in the liver of patients with nonalcoholic fatty liver disease (NAFLD), a disease sharing many similarities with ALD. Therefore, clinical trials investigating the expression of PPARα in the liver of ALD patients and the efficacy of strong PPARα agonists for the prevention and treatment of ALD are warranted.

Diet induces hepatocyte protection in fatty liver disease via modulation of PTEN signaling

Fatty liver disease (FLD) is characterized by accumulation of excess fat in the liver. The underlying molecular mechanism associated with the progression of the disease has been in elusive. Hepatocellular demise due to increased oxidative stress resulting in an inflammatory response may be a key feature in FLD. Recent advances in molecular biology have led to an improved understanding of the molecular pathogenesis, suggesting a critical association between the PI3K/AKT/PTEN signaling pathway and FLD. In particular, PTEN has been associated with regulating the pathogenesis of hepatocyte degeneration. Given the function of mitochondria in reactive oxygen species (ROS) generation and the initiation of oxidative stress, the mitochondrial antioxidant network is of interest. It is vital to balance the activity of intracellular key molecules to maintain a healthy liver. Consequently, onset of FLD may be delayed using dietary protective agents that alter PTEN signaling and reduce ROS levels. The advancement of research on dietary regulation with a focus on modulatory roles in ROS generation and PTEN associated signaling is summarized in the current study, supporting further preventive and therapeutic exploration.