A Mechanistic Review of Cell Death in Alcohol-Induced Liver Injury

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.

PSTPIP2 protects against alcoholic liver injury and invokes STAT3-mediated suppression of apoptosis

Alcoholic liver injury (ALI) stands as a prevalent affliction within the spectrum of complex liver diseases. Prolonged and excessive alcohol consumption can pave the way for liver fibrosis, cirrhosis, and even hepatocellular carcinoma. Recent findings have unveiled the protective role of proline serine-threonine phosphatase interacting protein 2 (PSTPIP2) in combating liver ailments. However, the role of PSTPIP2 in ALI remains mostly unknown. This study aimed to determine the expression profile of PSTPIP2 in ALI and to uncover the mechanism through which PSTPIP2 affects the survival and apoptosis of hepatocytes in ALI, using both ethyl alcohol (EtOH)-fed mice and an EtOH-induced AML-12 cell model. We observed a consistent decrease in PSTPIP2 expression both in vivo and in vitro. Functionally, we assessed the impact of PSTPIP2 overexpression on ALI by administering adeno-associated virus 9 (AAV9)-PSTPIP2 into mice. The results demonstrated that augmenting PSTPIP2 expression significantly shielded against liver parenchymal distortion and curbed caspase-dependent hepatocyte apoptosis in EtOH-induced ALI mice. Furthermore, enforcing PSTPIP2 expression reduced hepatocyte apoptosis in a stable PSTPIP2-overexpressing AML-12 cell line established through lentivirus-PSTPIP2 transfection in vitro. Mechanistically, this study also identified signal transducer and activator of transcription 3 (STAT3) as a direct signaling pathway regulated by PSTPIP2 in ALI. In conclusion, our findings provide compelling evidence that PSTPIP2 has a regulatory role in hepatocyte apoptosis via the STAT3 pathway in ALI, suggesting PSTPIP2 as a promising therapeutic target for ALI.

Ginseng fermentation solution affects the gut microbiota in zebrafish with alcoholic liver disease via PI3K/Akt pathway

BACKGROUND

Ginsenosides have received increased amounts of attention due to their ability to modulate the intestinal flora, which may subsequently alleviate alcoholic liver disease (ALD). The effects of ginseng fermentation solution (GFS) on the gut microbiota and metabolism in ALD patients have not been explored.

PURPOSE

This research aimed to explore the regulatory effect of GFS on ALD both in vitro and in vivo.

METHOD

This study assessed the anti-ALD efficacy of GFS using an LO2 cell model and a zebrafish model. Untargeted metabolomics was used for differentially abundant metabolite analysis, and high-throughput 16S rRNA sequencing was used to examine the effect of GFS on ALD.

RESULTS

The LO2 cell line experiments demonstrated that GFS effectively mitigated alcohol-induced oxidative stress and reduced apoptosis by upregulating PI3K and Bcl-2 expression and decreasing the levels of malondialdehyde, total cholesterol, and triglycerides. In zebrafish, GFS improved morphological and physiological parameters and diminished oxidative stress-induced ALD. Meanwhile, the results from Western blotting indicated that GFS enhanced the expression of PI3K, Akt, and Bcl-2 proteins while reducing Bax protein expression, thereby ameliorating the ALD model in zebrafish. Metabolomics data revealed significant changes in a total of 46 potential biomarkers. Among them, metabolites such as prostaglandin F2 alpha belong to arachidonic acid metabolism. In addition, GFS also partly reversed the imbalance of gut microbiota composition caused by alcohol. At the genus level, alcohol consumption elevated the presence of Flectobacillus, Curvibacter, among others, and diminished Elizabethkingia within the intestinal microbes of zebrafish. Conversely, GFS reversed these effects, notably enhancing the abundance of Proteobacteria and Archaea. Correlation analyses further indicated a significant negative correlation between prostaglandin F2 alpha, 11,14,15-THETA, Taurocholic acid and Curvibacter.

CONCLUSION

This study highlights a novel mechanism by which GFS modulates anti-ALD activity through the PI3K/Akt signalling pathway by influencing the intestinal flora-metabolite axis. These results indicate the potential of GFS as a functional food for ALD treatment via modulation of the gut flora.

Bioactive peptides as a novel strategy to prevent alcoholic liver injury

Alcohol intake has become one of the leading risks to human health and wellness, among which acute and/or chronic alcohol-induced liver injury is a leading threaten, with few therapeutic options other than abstinence. In recent years, studies suggested that certain bioactive peptides from food sources could represent natural and safe alternatives for the prevention of alcoholic liver injury. Hence, this chapter focus on the advanced research on bioactive peptides exerting hepatoprotective activity against alcoholic liver injury. The main sources of protein, strategies for the preparation of hepatoprotective hydrolysates and peptides, underlying mechanisms of peptides on hepatoprotection, and possible structure-activity relationship between peptides and hepatoprotective activity were summarized and discussed, aiming to give a systematic insight into the research progress of hepatoprotective peptides. However, more efforts would be needed to give a clearer insight into the underlying mechanisms and structure-activity relationship before using hepatoprotective peptides as functional food ingredients or dietary supplements.

A model of alcoholic liver disease based on different hepatotoxics leading to liver cancer

The worst-case scenario related to alcoholic liver disease (ALD) arises after a long period of exposure to the harmful effect of alcohol consumption along with other hepatotoxics. ALD encompasses a broad spectrum of liver-associated disorders, such as steatosis, steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Based on the chronic administration of different hepatotoxics, including ethanol, sucrose, lipopolysaccharide, and low doses of diethylnitrosamine over a short period, here we aimed to develop a multiple hepatotoxic (MHT)-ALD model in the mouse that recapitulates the human ALD-associated disorders. We demonstrated that the MHT-ALD model induces ADH1A and NXN, an ethanol metabolizer and a redox-sensor enzyme, respectively; promotes steatosis associated with the induction of the lipid droplet forming FSP27, inflammation identified by the infiltration of hepatic neutrophils-positive to LY-6G marker, and the increase of MYD88 level, a protein involved in inflammatory response; and stimulates the early appearance of cellular senescence identified by the senescence markers SA-β-gal activity and p-H2A.XSer139. It also induces fibrosis associated with increased desmin, a marker of hepatic stellate cells whose activation leads to the deposition of collagen fibers, accompanied by cell death and compensatory proliferation revealed by increased CASP3-mediated apoptosis, and KI67- and PCNA-proliferation markers, respectively. It also induces histopathological traits of malignancy and the level of the HCC marker, GSTP1. In conclusion, we provide a useful model for exploring the chronological ALD-associated alterations and stages, and addressing therapeutic approaches.

Advances in the Pathogenesis of Metabolic Liver Disease-Related Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the sixth most common cancer globally and the primary cause of death in cancer cases, with significant public health concern worldwide. Despite the overall decline in the incidence and mortality rates of HCC in recent years in recent years, the emergence of metabolic liver disease-related HCC is causing heightened concern, especially in countries like the United States, the United Kingdom, and P.R. China. The escalation of metabolic liver disease-related HCC is attributed to a combination of factors, including genetic predisposition, lifestyle choices, and changes in the living environment. However, the pathogenesis of metabolic liver disease-associated HCC remains imperfect. In this review, we encapsulate the latest advances and essential aspects of the pathogenesis of metabolic liver disease-associated HCC, including alcoholic liver disease (ALD), metabolic dysfunction-associated steatotic liver disease (MASLD), and inherited metabolic liver diseases.

The protective effect of Enteromorpha prolifera polysaccharide on alcoholic liver injury in C57BL/6 mice

An alcohol-induced liver injury model was induced in C57BL/6 mice to assess the protective efficacy of Enteromorpha prolifera polysaccharides (EP) against liver damage. Histological alterations in the liver were examined following hematoxylin-eosin (H&E) staining. Biochemical assay kits and ELISA kits were employed to analyze serum and liver biochemical parameters, as well as the activity of antioxidant enzymes and alcohol metabolism-related enzymes. The presence of oxidative stress-related proteins in the liver was detected using western blotting. Liquid chromatography and mass spectrometry were used to profile serum metabolites in mice. The findings demonstrated that EP-H (100 mg/Kg) reduced serum ALT and AST activity by 2.31-fold and 2.32-fold, respectively, when compared to the alcohol-induced liver injury group. H&E staining revealed a significant attenuation of microvesicular steatosis and ballooning pathology in the EP-H group compared to the model group. EP administration was found to enhance alcohol metabolism by regulating metabolite-related enzymes (ADH and ALDH) and decreasing CYP2E1 expression. EP also modulated the Nrf2/HO-1 signaling pathway to bolster hepatic antioxidant capacity. Furthermore, EP restored the levels of lipid metabolites (Glycine, Butanoyl-CoA, and Acetyl-CoA) to normalcy. In summary, EP confers protection to the liver through the regulation of antioxidant activity and lipid metabolites in the murine liver.

Distinct Types of Cell Death and Implications in Liver Diseases: An Overview of Mechanisms and Application

Cell death is associated with a variety of liver diseases, and hepatocyte death is a core factor in the occurrence and progression of liver diseases. In recent years, new cell death modes have been identified, and certain biomarkers have been detected in the circulation during various cell death modes that mediate liver injury. In this review, cell death modes associated with liver diseases are summarized, including some cell death modes that have emerged in recent years. We described the mechanisms associated with liver diseases and summarized recent applications of targeting cell death in liver diseases. It provides new ideas for the diagnosis and treatment of liver diseases. In addition, multiple cell death modes can contribute to the same liver disease. Different cell death modes are not isolated, and they interact with each other in liver diseases. Future studies may focus on exploring the regulation between various cell death response pathways in liver diseases.

Acetyl-L-carnitine attenuates chronic ethanol-induced oxidative stress, ER stress and apoptosis in rat gastric tissue

Consuming alcohol affects almost all organs. Acetaldehyde, formed as the main product as a result of alcohol metabolism, causes the production of free superoxide radicals when oxidized, and accordingly oxidative and apoptotic processes are triggered. There are studies showing that carnitine has effects on oxidative and apoptotic processes that occur in various conditions. However, the mechanisms showing the effects of L-carnitine on these effects of alcohol have not been fully elucidated. In our study, the effects of acetyl-L-carnitine administration on the molecular mechanisms of oxidative stress, endoplasmic reticulum stress, and apoptotic parameters in gastric tissue of rats chronically exposed to alcohol were investigated. Hematoxylin-eosin staining was used for histopathological studies. Endoplasmic reticulum stress markers were detected with immunohistochemical staining and western blotting. Apoptotic index was evaluated by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. Total oxidant and antioxidant status were examined by ELISA. Our results showed that chronic alcohol administration caused a significant increase in TOS levels, an indicator of oxidative stress, the levels of ER-stress-associated proteins XBP1, GRP78, and CHOP, and % apoptotic index values in rat gastric tissues. Additionally, it was determined that acetyl-L-carnitine administration caused an improvement in those values. Based on our data, we can conclude that acetyl-L-carnitine has a tissue protective effect by scavenging free oxygen radicals and reducing ER stress-related proteins XBP1, GRP78, and CHOP and apoptosis in chronic ethanol-administered rats, and that this natural antioxidant may be beneficial in the treatment of oxidative stress-induced diseases.

Hepatocyte-derived biomarkers predict liver-related events at 2 years in Child-Pugh class A alcohol-related cirrhosis

BACKGROUND & AIMS

In patients with compensated alcohol-related cirrhosis, reliable prognostic biomarkers are lacking. Keratin-18 and hepatocyte-derived large extracellular vesicle (lEV) concentrations reflect disease activity, but their ability to predict liver-related events is unknown.

METHODS

We measured plasma keratin-18 and hepatocyte lEV concentrations in 500 patients with Child-Pugh class A alcohol-related cirrhosis. The ability of these hepatocyte-derived biomarkers, alone or combined with model for end-stage liver disease (MELD) and FibroTest scores, to predict liver-related events at 2 years was analyzed, taking into account the alcohol consumption at inclusion and during follow-up.

RESULTS

Keratin-18 and hepatocyte lEV concentrations increased with alcohol consumption. In patients without active alcohol consumption at enrollment (n = 419), keratin-18 concentration predicted liver-related events at 2 years, independently of FibroTest and MELD. Patients with both keratin-18 concentrations >285 U/L and FibroTest >0.74 had a 24% cumulative incidence of liver-related events at 2 years, vs. 5% to 14% in other groups of patients. Similar results were obtained when combining keratin-18 concentrations >285 U/L with MELD >10. In patients with active alcohol consumption at enrollment (n = 81), hepatocyte lEVs predicted liver-related events at 2 years, independently of FibroTest and MELD. Patients with both hepatocyte lEV concentrations >50 U/L and FibroTest >0.74 had a 62% cumulative incidence of liver-related events at 2 years, vs. 8% to 13% in other groups of patients. Combining hepatocyte lEV concentrations >50 U/L with MELD >10 had a lower discriminative ability. Similar results were obtained when using decompensation of cirrhosis, defined according to Baveno VII criteria, as an endpoint.

CONCLUSION

In patients with Child-Pugh class A alcohol-related cirrhosis, combining hepatocyte-derived biomarkers with FibroTest or MELD scores identifies patients at high risk of liver-related events, and could be used for risk stratification and patient selection in clinical trials.

IMPACT AND IMPLICATIONS

In patients with compensated alcohol-related cirrhosis, reliable predictors of outcome are lacking. In patients with Child-Pugh class A alcohol-related cirrhosis, combining hepatocyte-derived biomarkers (keratin-18 and hepatocyte-large extracellular vesicles) with FibroTest or MELD scores identifies those at high risk of liver-related events at 2 years. The identified patients at high risk of liver-related events are the target-of-choice population for intensive surveillance (e.g., referral to tertiary care centers; intensive control of risk factors) and inclusion in clinical trials.

Role of ERK1/2 Signaling in Cinnabarinic Acid-Driven Stanniocalcin 2-Mediated Protection against Alcohol-Induced Apoptosis

We have previously shown that a bona fide aryl hydrocarbon receptor (AhR) agonist, cinnabarinic acid (CA), protects against alcohol-induced hepatocyte apoptosis via activation of a novel AhR target gene, stanniocalcin 2 (Stc2). Stc2 translates to a secreted disulfide-linked hormone, STC2, known to function in cell development, calcium and phosphate regulation, angiogenesis, and antiapoptosis-albeit the comprehensive mechanism by which the CA-AhR-STC2 axis confers antiapoptosis is yet to be characterized. In this study, using RNA interference library screening, downstream antiapoptotic molecular signaling components involved in CA-induced STC2-mediated protection against ethanol-induced apoptosis were investigated. RNA interference library screening of kinases and phosphatases in Hepa1 cells and subsequent pathway analysis identified mitogen-activated protein kinase (MAPK) signaling as a critical molecular pathway involved in CA-mediated protection. Specifically, phosphorylation of ERK1/2 was induced in response to CA treatment without alterations in p38 and JNK signaling pathways. Silencing Stc2 in Hepa1 cells and in vivo experiments performed in Stc2-/- (Stc2 knockout) mice, which failed to confer CA-mediated protection against ethanol-induced apoptosis, showed abrogation of ERK1/2 activation, underlining the significance of ERK1/2 signaling in CA-STC2-mediated protection. In conclusion, activation of ERK1/2 signaling in CA-driven AhR-dependent Stc2-mediated protection represents a novel mechanism of protection against acute alcohol-induced apoptosis. SIGNIFICANCE STATEMENT: Previous studies have shown the role of stanniocalcin 2 (Stc2) in cinnabarinic acid (CA)-mediated protection against alcohol-induced apoptosis. Here, using RNA interference library screening and subsequent in vivo studies, the functional significance of ERK1/2 activation in CA-induced Stc2-mediated protection against acute ethanol-induced apoptosis was identified. This study is thus significant as it illustrates a comprehensive downstream mechanism by which CA-induced Stc2 protects against alcoholic liver disease.

Management of alcoholic hepatitis: A clinical perspective

Alcohol-associated liver disease is the primary cause of liver-related mortality worldwide and one of the most common indications for liver transplantation. Alcoholic hepatitis represents the most acute and severe manifestation of alcohol-associated liver disease and is characterized by a rapid onset of jaundice with progressive inflammatory liver injury, worsening of portal hypertension, and an increased risk for multiorgan failure in patients with excessive alcohol consumption. Severe alcoholic hepatitis is associated with a poor prognosis and high short-term mortality. During the COVID-19 pandemic, rates of alcohol-associated hepatitis have increased significantly, underscoring that it is a serious and growing health problem. However, adequate management of alcohol-associated hepatitis and its complications in everyday clinical practice remains a major challenge. Currently, pharmacotherapy is limited to corticosteroids, although these have only a moderate effect on reducing short-term mortality. In recent years, translational studies deciphering key mechanisms of disease development and progression have led to important advances in the understanding of the pathogenesis of alcoholic hepatitis. Emerging pathophysiology-based therapeutic approaches include anti-inflammatory agents, modifications of the gut-liver axis and intestinal dysbiosis, epigenetic modulation, antioxidants, and drugs targeting liver regeneration. Concurrently, evidence is increasing that early liver transplantation is a safe treatment option with important survival benefits in selected patients with severe alcoholic hepatitis not responding to medical treatment. This narrative review describes current pathophysiology and management concepts of alcoholic hepatitis, provides an update on emerging treatment options, and focuses on the need for holistic and patient-centred treatment approaches to improve prognosis.

System Biology Investigation Revealed Lipopolysaccharide and Alcohol-Induced Hepatocellular Carcinoma Resembled Hepatitis B Virus Immunobiology and Pathogenesis

Hepatitis B infection caused by the hepatitis B virus is a life-threatening cause of liver fibrosis, cirrhosis, and hepatocellular carcinoma. Researchers have produced multiple in vivo models for hepatitis B virus (HBV) and, currently, there are no specific laboratory animal models available to study HBV pathogenesis or immune response; nonetheless, their limitations prevent them from being used to study HBV pathogenesis, immune response, or therapeutic methods because HBV can only infect humans and chimpanzees. The current study is the first of its kind to identify a suitable chemically induced liver cirrhosis/HCC model that parallels HBV pathophysiology. Initially, data from the peer-reviewed literature and the GeneCards database were compiled to identify the genes that HBV and seven drugs (acetaminophen, isoniazid, alcohol, D-galactosamine, lipopolysaccharide, thioacetamide, and rifampicin) regulate. Functional enrichment analysis was performed in the STRING server. The network HBV/Chemical, genes, and pathways were constructed by Cytoscape 3.6.1. About 1546 genes were modulated by HBV, of which 25.2% and 17.6% of the genes were common for alcohol and lipopolysaccharide-induced hepatitis. In accordance with the enrichment analysis, HBV activates the signaling pathways for apoptosis, cell cycle, PI3K-Akt, TNF, JAK-STAT, MAPK, chemokines, NF-kappa B, and TGF-beta. In addition, alcohol and lipopolysaccharide significantly activated these pathways more than other chemicals, with higher gene counts and lower FDR scores. In conclusion, alcohol-induced hepatitis could be a suitable model to study chronic HBV infection and lipopolysaccharide-induced hepatitis for an acute inflammatory response to HBV.

Effect of Hepatic Pathology on Liver Regeneration: The Main Metabolic Mechanisms Causing Impaired Hepatic Regeneration

Liver regeneration has been studied for many decades, and the mechanisms underlying regeneration of normal liver following resection are well described. However, no less relevant is the study of mechanisms that disrupt the process of liver regeneration. First of all, a violation of liver regeneration can occur in the presence of concomitant hepatic pathology, which is a key factor reducing the liver's regenerative potential. Understanding these mechanisms could enable the rational targeting of specific therapies to either reduce the factors inhibiting regeneration or to directly stimulate liver regeneration. This review describes the known mechanisms of normal liver regeneration and factors that reduce its regenerative potential, primarily at the level of hepatocyte metabolism, in the presence of concomitant hepatic pathology. We also briefly discuss promising strategies for stimulating liver regeneration and those concerning methods for assessing the regenerative potential of the liver, especially intraoperatively.

Fatty Liver Disease, Metabolism and Alcohol Interplay: A Comprehensive Review

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide, and its incidence has been increasing in recent years because of the high prevalence of obesity and metabolic syndrome in the Western population. Alcohol-related liver disease (ArLD) is the most common cause of cirrhosis and constitutes the leading cause of cirrhosis-related deaths worldwide. Both NAFLD and ArLD constitute well-known causes of liver damage, with some similarities in their pathophysiology. For this reason, they can lead to the progression of liver disease, being responsible for a high proportion of liver-related events and liver-related deaths. Whether ArLD impacts the prognosis and progression of liver damage in patients with NAFLD is still a matter of debate. Nowadays, the synergistic deleterious effect of obesity and diabetes is clearly established in patients with ArLD and heavy alcohol consumption. However, it is still unknown whether low to moderate amounts of alcohol are good or bad for liver health. The measurement and identification of the possible synergistic deleterious effect of alcohol consumption in the assessment of patients with NAFLD is crucial for clinicians, since early intervention, advising abstinence and controlling cardiovascular risk factors would improve the prognosis of patients with both comorbidities. This article seeks to perform a comprehensive review of the pathophysiology of both disorders and measure the impact of alcohol consumption in patients with NAFLD.

Fpr2-/- Mice Developed Exacerbated Alcohol-Associated Liver Disease

Alcohol-associated liver disease (ALD) is the most common chronic liver disease and carries a significant healthcare burden. ALD has no long-term treatment options aside from abstinence, and the mechanisms that contribute to its pathogenesis are not fully understood. This study aimed to investigate the role of formyl peptide receptor 2 (FPR2), a receptor for immunomodulatory signals, in the pathogenesis of ALD. WT and Fpr2-/- mice were exposed to chronic-binge ethanol administration and subsequently assessed for liver injury, inflammation, and markers of regeneration. The differentiation capacity of liver macrophages and the oxidative burst activity of neutrophils were also examined. Compared to WT, Fpr2-/- mice developed more severe liver injury and inflammation and had compromised liver regeneration in response to ethanol administration. Fpr2-/- mice had fewer hepatic monocyte-derived restorative macrophages, and neutrophils isolated from Fpr2-/- mice had diminished oxidative burst capacity. Fpr2-/- MoMF differentiation was restored when co-cultured with WT neutrophils. Loss of FPR2 led to exacerbated liver damage via multiple mechanisms, including abnormal immune responses, indicating the crucial role of FPR2 in ALD pathogenesis.

PTTG1 alleviates acute alcoholic liver injury by inhibiting endoplasmic reticulum stress-induced hepatocyte pyroptosis

BACKGROUND & AIMS

Heavy drinking is a primary cause of alcoholic liver injury (ALI). Pituitary tumour transforming gene 1 (PTTG1) is involved in the occurrence and development of hepatocellular carcinoma (HCC), which is a well-known inflammation-related cancer with various aetiologies, including alcohol consumption. However, the role of PTTG1 in alcohol-induced liver injury and inflammation is not clear.

METHODS

Blood samples were collected from patients with acute alcohol intoxication (n = 20) and healthy controls (n = 20). PTTG1 knockout (KO) mice and PTTG1 transgenic (TG) mice were given a single gavage of alcohol (5 g/kg, 50%) to construct the alcohol-induced liver injury.

RESULTS

We found that serum PTTG1 levels were downregulated in acute ALI patients. In addition, acute alcohol administration significantly reduced PTTG1 levels in the serum and liver of mice. Compared to wild-type mice, PTTG1 KO mice had more serious liver injury, which was accompanied by worsened hepatic endoplasmic reticulum (ER) stress and hepatocyte pyroptosis induced by alcohol. Similarly, PTTG1 deficiency exacerbated alcohol-induced cell death in primary mouse hepatocytes and LO2 cells, by increasing hepatic ER stress and pyroptosis. Importantly, TUDCA, an ER stress inhibitor, could blocked alcohol-induced hepatic pyroptosis in PTTG1 knockdown LO2 cells. Finally, overexpression of PTTG1 substantially attenuated alcohol-induced liver injury by reducing ER stress and hepatic pyroptosis in mice.

CONCLUSIONS

We demonstrated that PTTG1 participates in ALI and has a protective effect against alcohol-induced hepatic ER stress and pyroptosis.

Alcohol, Inflammation, and Microbiota in Alcoholic Liver Disease

Alcoholic liver disease (ALD) is a consequence of excessive alcohol use. According to many studies, alcohol represents a significant socioeconomic and health risk factor in today's population. According to data from the World Health Organization, there are about 75 million people who have alcohol disorders, and it is well known that its use leads to serious health problems. ALD is a multimodality spectrum that includes alcoholic fatty liver disease (AFL) and alcoholic steatohepatitis (ASH), consequently leading to liver fibrosis and cirrhosis. In addition, the rapid progression of alcoholic liver disease can lead to alcoholic hepatitis (AH). Alcohol metabolism produces toxic metabolites that lead to tissue and organ damage through an inflammatory cascade that includes numerous cytokines, chemokines, and reactive oxygen species (ROS). In the process of inflammation, mediators are cells of the immune system, but also resident cells of the liver, such as hepatocytes, hepatic stellate cells, and Kupffer cells. These cells are activated by exogenous and endogenous antigens, which are called pathogen and damage-associated molecular patterns (PAMPs, DAMPs). Both are recognized by Toll-like receptors (TLRs), which activation triggers the inflammatory pathways. It has been proven that intestinal dysbiosis and disturbed integrity of the intestinal barrier perform a role in the promotion of inflammatory liver damage. These phenomena are also found in chronic excessive use of alcohol. The intestinal microbiota has an important role in maintaining the homeostasis of the organism, and its role in the treatment of ALD has been widely investigated. Prebiotics, probiotics, postbiotics, and symbiotics represent therapeutic interventions that can have a significant effect on the prevention and treatment of ALD.

Apoptosis in megakaryocytes: Safeguard and threat for thrombopoiesis

Platelets, generated from precursor megakaryocytes (MKs), are central mediators of hemostasis and thrombosis. The process of thrombopoiesis is extremely complex, regulated by multiple factors, and related to many cellular events including apoptosis. However, the role of apoptosis in thrombopoiesis has been controversial for many years. Some researchers believe that apoptosis is an ally of thrombopoiesis and platelets production is apoptosis-dependent, while others have suggested that apoptosis is dispensable for thrombopoiesis, and is even inhibited during this process. In this review, we will focus on this conflict, discuss the relationship between megakaryocytopoiesis, thrombopoiesis and apoptosis. In addition, we also consider why such a vast number of studies draw opposite conclusions of the role of apoptosis in thrombopoiesis, and try to figure out the truth behind the mystery. This review provides more comprehensive insights into the relationship between megakaryocytopoiesis, thrombopoiesis, and apoptosis and finds some clues for the possible pathological mechanisms of platelet disorders caused by abnormal apoptosis.

Rhizophora mucronata Lam. (Mangrove) Bark Extract Reduces Ethanol-Induced Liver Cell Death and Oxidative Stress in Swiss Albino Mice: In Vivo and In Silico Studies

The bark extract of Rhizophora mucronata (BERM) was recently reported for its prominent in vitro protective effects against liver cell line toxicity caused by various toxicants, including ethanol. Here, we aimed to verify the in vivo hepatoprotective effects of BERM against ethanol intoxication with the prediction of potential targets employing in silico studies. An oral administration of different concentrations (100, 200 and 400 mg/kg body weight) of BERM before high-dose ethanol via intraperitoneal injection was performed in mice. On day 7, liver sections were dissected for histopathological examination. The ethanol intoxication caused liver injury and large areas of necrosis. The pre-BERM administration decreased the ethanol-induced liver damage marker tumor necrosis factor-alpha (TNF-α) expression, reduced hepatotoxicity revealed by nuclear deoxyribonucleic acid (DNA) fragmentation and decreased oxidative stress indicated by malondialdehyde and glutathione contents. Our in silico studies have identified BERM-derived metabolites exhibiting the highest predicted antioxidant and free radical scavenger activities. Molecular docking studies showed that most of the metabolites were predicted to be enzyme inhibitors such as carbonic anhydrase inhibitors, which were reported to stimulate the antioxidant defense system. The metabolites predominantly presented acceptable pharmacokinetics and safety profiles, suggesting them as promising new antioxidant agents. Altogether, the BERM extract exerts antioxidative activities and shows promising hepatoprotective effects against ethanol intoxication. Identification of related bioactive compounds will be of interest for future use at physiological concentrations in ethanol-intoxicated individuals.

Role of Oxidative Stress in Liver Disorders

Oxygen is vital for life as it is required for many different enzymatic reactions involved in intermediate metabolism and xenobiotic biotransformation. Moreover, oxygen consumption in the electron transport chain of mitochondria is used to drive the synthesis of ATP to meet the energetic demands of cells. However, toxic free radicals are generated as byproducts of molecular oxygen consumption. Oxidative stress ensues not only when the production of reactive oxygen species (ROS) exceeds the endogenous antioxidant defense mechanism of cells, but it can also occur as a consequence of an unbalance between antioxidant strategies. Given the important role of hepatocytes in the biotransformation and metabolism of xenobiotics, ROS production represents a critical event in liver physiology, and increasing evidence suggests that oxidative stress contributes to the development of many liver diseases. The present review, which is part of the special issue “Oxidant stress in Liver Diseases”, aims to provide an overview of the sources and targets of ROS in different liver diseases and highlights the pivotal role of oxidative stress in cell death. In addition, current antioxidant therapies as treatment options for such disorders and their limitations for future trial design are discussed.

Role of mechanistic target of rapamycin in autophagy and alcohol-associated liver disease

Mechanistic target of rapamycin (mTOR) is a serine-threonine kinase and a cellular sensor for nutrient and energy status, which is critical in regulating cell metabolism and growth by governing the anabolic (protein and lipid synthesis) and catabolic process (autophagy). Alcohol-associated liver disease (ALD) is a major chronic liver disease worldwide that carries a huge financial burden. The spectrum of the pathogenesis of ALD includes steatosis, fibrosis, inflammation, ductular reaction, and eventual hepatocellular carcinoma, which is closely associated with metabolic changes that are regulated by mTOR. In this review, we summarized recent progress of alcohol consumption on the changes of mTORC1 and mTORC2 activity, the potential mechanisms and possible impact of the mTORC1 changes on autophagy in ALD. We also discussed the potential beneficial effects and limitations of targeting mTORC1 against ALD.

Cellular Bioenergetics: Experimental Evidence for Alcohol-induced Adaptations

At-risk alcohol use is associated with multisystemic effects and end-organ injury, and significantly contributes to global health burden. Several alcohol-mediated mechanisms have been identified, with bioenergetic maladaptation gaining credence as an underlying pathophysiological mechanism contributing to cellular injury. This evidence-based review focuses on the current knowledge of alcohol-induced bioenergetic adaptations in metabolically active tissues: liver, cardiac and skeletal muscle, pancreas, and brain. Alcohol metabolism itself significantly interferes with bioenergetic pathways in tissues, particularly the liver. Alcohol decreases states of respiration in the electron transport chain, and activity and expression of respiratory complexes, with a net effect to decrease ATP content. In addition, alcohol dysregulates major metabolic pathways, including glycolysis, the tricarboxylic acid cycle, and fatty acid oxidation. These bioenergetic alterations are influenced by alcohol-mediated changes in mitochondrial morphology, biogenesis, and dynamics. The review highlights similarities and differences in bioenergetic adaptations according to tissue type, pattern of (acute vs. chronic) alcohol use, and energy substrate availability. The compromised bioenergetics synergizes with other critical pathophysiological mechanisms, including increased oxidative stress and accelerates cellular dysfunction, promoting senescence, programmed cell death, and end-organ injury.

Probiotic Lactobacilli ameliorate alcohol-induced hepatic damage via gut microbial alteration

Alcoholic liver disease (ALD), which includes fatty liver, cirrhosis, steatosis, fibrosis, and hepatocellular carcinoma, is a global health problem. The probiotic effects of lactic acid bacteria (LAB) are well-known; however, their protective effect against ALD remains unclear. Therefore, in this study, our objective was to assess the protective effects of LAB on ALD. To this end, mice were fed either a normal diet or an alcohol diet for 10 days (to induce ALD) accompanied by vehicle treatment (the NC and AC groups) or kimchi-derived LAB (Lactiplantibacillus plantarum DSR J266 and Levilactobacillus brevis DSR J301, the AL group; or Lacticaseibacillus rhamnosus GG, the AG group). Our results showed that mice in the AC group showed significantly higher serum aspartate aminotransferase and alanine aminotransferase levels than those in the normal diet groups; however, their levels in the AL and AG groups were relatively lower. We also observed that the AL and AG groups showed relatively lower interleukin-6 levels than the AC group. Additionally, AC group showed the accumulation of several fat vesicles in the liver, while the AL and AG groups showed remarkably lower numbers of fat vesicles. The relative abundance of Enterococcus feacalis, which showed association with liver injury, significantly increased in the AC group compared with its levels in the normal diet groups. However, the AG group showed a decreased relative abundance in this regard, confirming that LAB exerted an improvement effect on gut microbial community. These findings suggested that via gut microbiota alteration, the ingestion of LAB can alleviate the ill effects of alcohol consumption, including inflammation, liver damage, gut dysbiosis, and abnormal intestinal nutrient metabolism.

Beneficial Effects of lncRNA-UC.360+ shRNA on Diabetic Cardiac Sympathetic Damage via NLRP3 Inflammasome-Induced Pyroptosis in Stellate Ganglion

Hyperglycemia is one of the common symptoms of diabetes, and it produces excessive reactive oxygen species (ROS). This study investigated whether the long noncoding RNA (lncRNA) UC.360+ is involved in diabetic cardiac autonomic neuropathy (DCAN) mediated by NLRP3 inflammasome-induced pyroptosis in the stellate ganglion (SG). Using a rat type 2 diabetes model, we found that lncRNA UC.360+ short hairpin RNA (shRNA) ameliorated the dyslipidaemia of type 2 diabetic rats and reduced serum adrenaline and ROS production in SG under hyperglycemia. In addition, UC.360+ shRNA also reduced the expression of nuclear factor kappa-B (NF-κB), NLRP3, ASC, caspase-1, interleukin-1β (IL-1β), and IL-18 in the SG of diabetic rats and inhibited the phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK). Therefore, lncRNA-UC.360+ shRNA may modulate the NLRP3 inflammasome/inflammatory pathway in the SG, which in turn alleviates diabetic heart sympathetic nerve damage.

Ameliorating effects of water bamboo shoot (Zizania latifolia) on acute alcoholism in a mice model and its chemical composition

In this study, the ameliorative effect of water bamboo shoot (WBS) on acute alcoholism mice was investigated and potential biological compounds were explored. Results showed that extraction methods significantly affected the active substances contents and bioactivities of WBS. Principal component analysis (PCA) showed that alkali extract (NE) obtained the highest score, therefore, it was selected for further analysis. Animal experiments showed that NE demonstrated ameliorative effects on acute alcoholism mice as evident by significantly elevated activities of dehydrogenase (alcohol dehydrogenase, acetaldehyde dehydrogenase) and antioxidant enzymes (superoxide dismutase, glutathione peroxidase, catalase), whereas significantly reduced the levels of aminotransferase (alanine aminotransferase, aspartate aminotransferase) in serum. The potential bioactive activity compounds of NE were explored by UPLC-MS/MS and bioinformatics analysis. Butyl isobutyl phthalate vanillin, ferulic acid methyl ester might be the major compounds in NE on alleviating acute alcoholism. These results indicated that WBS possesses potential ameliorating effect on acute alcoholism.

FUN14 Domain Containing 1 (FUNDC1): A Promising Mitophagy Receptor Regulating Mitochondrial Homeostasis in Cardiovascular Diseases

Mitochondria, the intracellular organelles for cellular aerobic respiration and energy production, play an important role in the regulation of cell metabolism and cell fate. Mitophagy, a selective form of autophagy, maintains dynamic homeostasis of cells through targeting long-lived or defective mitochondria for timely clearance and recycling. Dysfunction in mitophagy is involved in the molecular mechanism responsible for the onset and development of human diseases. FUN14 domain containing 1 (FUNDC1) is a mitochondrial receptor located in the outer mitochondria membrane (OMM) to govern mitophagy process. Emerging evidence has demonstrated that levels and phosphorylation states of FUNDC1 are closely related to the occurrence, progression and prognosis of cardiovascular diseases, indicating a novel role for this mitophagy receptor in the regulation of mitochondrial homeostasis in cardiovascular system. Here we review mitophagy mediated by FUNDC1 in mitochondria and its role in various forms of cardiovascular diseases.

Cinnabarinic Acid-Induced Stanniocalcin 2 Confers Cytoprotection against Alcohol-Induced Liver Injury

We recently identified upregulation of a novel aryl hydrocarbon receptor (AhR) target gene, stanniocalcin 2 (STC2), by an endogenous AhR agonist, cinnabarinic acid (CA). STC2 is a disulfide-linked homodimeric secreted glycoprotein that plays a role in various physiologic processes, including cell metabolism, inflammation, endoplasmic reticulum (ER) and oxidative stress, calcium regulation, cell proliferation, and apoptosis. Our previous studies have confirmed that CA-induced AhR-dependent STC2 expression was able to confer cytoprotection both in vitro and in vivo in response to injury induced by variety of ER/oxidative insults. Here, we used mouse models of chronic and acute ethanol feeding and demonstrated that upregulation of STC2 by CA was critical for cytoprotection. In STC2 knockout mice (STC2-/-), CA failed to protect against both acute as well as chronic-plus-binge ethanol-induced liver injury, whereas re-expression of STC2 in the liver using in vivo gene delivery restored cytoprotection against injury based on measures of apoptosis and serum levels of liver enzymes, underlining STC2's indispensable function in cell survival. In conclusion, the identification of STC2 as an AhR target gene receptive to CA-mediated endogenous AhR signaling and STC2's role in providing cytoprotection against liver injury represents a key finding with potentially significant therapeutic implications. SIGNIFICANCE STATEMENT: We recently identified stanniocalcin 2 (STC2) as a novel aryl hydrocarbon receptor (AhR) target gene regulated by endogenous AhR agonist and tryptophan metabolite, cinnabarinic acid (CA). Here, we showed that CA-induced STC2 expression conferred cytoprotection against apoptosis, steatosis, and liver injury in chronic as well as acute models of ethanol feeding. Therefore, this study will prove instrumental in developing CA as a promising lead compound for future drug development against hepatic diseases.

Oyster broth concentrate and its major component taurine alleviate acute alcohol‐induced liver damage

Our previous study showed that oyster hydrolysate (OH) protected against the liver damage caused by a single instance of ethanol (EtOH) binge drinking. Oyster broth concentrate (OBC) was discovered in the process of searching for a different substance derived from oysters (Crassostrea gigas) with economic value. OBC is a by‐product of boiling oysters at 95°C for 3 min. In this study, we investigated the effects of OBC and its major component taurine on blood and liver tissues obtained from a single‐EtOH‐binge‐drinking mouse model. The preadministration of OBC enhanced EtOH metabolism by increasing the activities of alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), and catalase. In addition, the preadministration of OBC reduced cytochrome P450 2E1 (CYP2E1) activity, reactive oxygen species (ROS) generation, Ca²⁺ concentrations, apoptotic signals, and inflammatory mediators in liver tissues. The reduction of apoptotic and inflammatory signals by OBC resulted from the downregulation of endoplasmic reticulum (ER) stress molecules and NF‐κB activity. Taurine administration showed similar effects to OBC. These results show that OBC protected against acute EtOH‐induced liver damage through the action of taurine. Our findings suggest that OBC could be an economically valuable substance and a functional food with hepatoprotective effects.

Alcohol-Associated Tissue Injury: Current Views on Pathophysiological Mechanisms

At-risk alcohol use is a major contributor to the global health care burden and leads to preventable deaths and diseases including alcohol addiction, alcoholic liver disease, cardiovascular disease, diabetes, traumatic injuries, gastrointestinal diseases, cancers, and fetal alcohol syndrome. Excessive and frequent alcohol consumption has increasingly been linked to alcohol-associated tissue injury and pathophysiology, which have significant adverse effects on multiple organ systems. Extensive research in animal and in vitro models has elucidated the salient mechanisms involved in alcohol-induced tissue and organ injury. In some cases, these pathophysiological mechanisms are shared across organ systems. The major alcohol- and alcohol metabolite-mediated mechanisms include oxidative stress, inflammation and immunometabolic dysregulation, gut leak and dysbiosis, cell death, extracellular matrix remodeling, endoplasmic reticulum stress, mitochondrial dysfunction, and epigenomic modifications. These mechanisms are complex and interrelated, and determining the interplay among them will make it possible to identify how they synergistically or additively interact to cause alcohol-mediated multiorgan injury. In this article, we review the current understanding of pathophysiological mechanisms involved in alcohol-induced tissue injury.

The role of MLKL in Hepatic Ischemia-Reperfusion Injury of Alcoholic Steatotic Livers

Alcohol-related liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) are the primary causes of chronic liver disease in western countries. Liver transplantation is currently one of the most efficient approaches to save patients with liver failure, which is often associated with hepatic ischemia-reperfusion (IR) injury. IR injury is exacerbated by hepatic steatosis, yet the mechanism remains elusive. Necroptosis is a form of regulated cell death mediated by receptor-interacting protein kinase 1 (RIP1), RIP3 and mixed lineage kinase domain-like (MLKL) protein, which has been implicated in the pathogenesis of ALD and NAFLD. Though necroptosis plays an important role in IR injury of high fat diet - induced steatotic livers, the role of necroptosis in IR injury of ethanol - induced steototic livers has not been investigated. In the present study, we used chronic plus binge alcohol (Gao-binge) feeding followed by IR surgery to investigate IR liver injury with ethanol-associated steatosis. We found that the levels of key necroptotic proteins MLKL and RIP3 increased in alcohol-fed mouse livers. Moreover, we observed increased liver injury after IR in control diet-fed mice, which was further exacerbated by alcohol feeding based on serum alanine aminotransferase (ALT) levels and TUNEL staining of necrotic cells. Hepatic neutrophil infiltration also increased in alcohol-fed mice after IR surgery. However, deletion of Mlkl did not protect against IR liver injury in alcohol-fed mice compared with matched wild-type mice. In conclusion, alcoholic steatosis promotes IR injury, which seems to be independent of MLKL-mediated necroptosis.

Association of Diabetes Mellitus and Alcohol Abuse with Cancer: Molecular Mechanisms and Clinical Significance

Diabetes mellitus (DM), one of the metabolic diseases which is characterized by sustained hyperglycemia, is a life-threatening disease. The global prevalence of DM is on the rise, mainly in low- and middle-income countries. Diabetes is a major cause of blindness, heart attacks, kidney failure, stroke, and lower limb amputation. Type 2 diabetes mellitus (T2DM) is a form of diabetes that is characterized by high blood sugar and insulin resistance. T2DM can be prevented or delayed by a healthy diet, regular physical activity, maintaining normal body weight, and avoiding alcohol and tobacco use. Ethanol and its metabolites can cause differentiation defects in stem cells and promote inflammatory injury and carcinogenesis in several tissues. Recent studies have suggested that diabetes can be treated, and its consequences can be avoided or delayed with proper management. DM has a greater risk for several cancers, such as breast, colorectal, endometrial, pancreatic, gallbladder, renal, and liver cancer. The incidence of cancer is significantly higher in patients with DM than in those without DM. In addition to DM, alcohol abuse is also a risk factor for many cancers. We present a review of the recent studies investigating the association of both DM and alcohol abuse with cancer incidence.

Generation of a Transgenic Zebrafish Line for In Vivo Assessment of Hepatic Apoptosis

Hepatic apoptosis is involved in a variety of pathophysiologic conditions in the liver, including hepatitis, steatosis, and drug-induced liver injury. The development of easy-to-perform and reliable in vivo assays would thus greatly enhance the efforts to understand liver diseases and identify associated genes and potential drugs. In this study, we developed a transgenic zebrafish line that was suitable for the assessment of caspase 3 activity in the liver by using in vivo fluorescence imaging. The larvae of transgenic zebrafish dominantly expressed Casper3GR in the liver under control of the promoter of the phosphoenolpyruvate carboxykinase 1 gene. Casper3GR is composed of two fluorescent proteins, tagGFP and tagRFP, which are connected via a peptide linker that can be cleaved by activated caspase 3. Under tagGFP excitation conditions in zebrafish that were exposed to the well-characterized hepatotoxicant isoniazid, we detected increased and decreased fluorescence associated with tagGFP and tagRFP, respectively. This result suggests that isoniazid activates caspase 3 in the zebrafish liver, which digests the linker between tagGFP and tagRFP, resulting in a reduction in the Förster resonance energy transfer to tagRFP upon tagGFP excitation. We also detected isoniazid-induced inhibition of caspase 3 activity in zebrafish that were treated with the hepatoprotectants ursodeoxycholic acid and obeticholic acid. The transgenic zebrafish that were developed in this study could be a powerful tool for identifying both hepatotoxic and hepatoprotective drugs, as well as for analyzing the effects of the genes of interest to hepatic apoptosis.

Long non-coding RNA CRNDE as potential biomarkers facilitate inflammation and apoptosis in alcoholic liver disease

Due to persistent inconsistencies in the expression data of alcoholic liver disease (ALD), it is necessary to turn to “pre-laboratory” comprehensive analysis in order to accelerate effective precision medicine and transformation research. We screened pseudogene-derived lncRNA associated with ALD by comparative analysis of 2 independent data sets from GEO. Three lncRNAs (CRNDE, RBMS3-AS3, and LINC01088) were demonstrated to be potentially useful diagnostic markers in ALD. Among them, the expression of CRNDE is up-regulated. Therefore, we focus on CRNDE. Kyoto Encyclopedia of Genes and Genomes pathways analysis revealed higher CRNDE can activate MAPK signaling pathway, apoptosis, wnt signaling pathway, and hematopoietic cell lineage. Next, we established ALD animal model and verified the success of the modeling. The result showed ALD tissues in mice had significantly higher CRNDE levels than normal tissues. Moreover, the increase of IL-6 in the serum of mice in the low-dose group is related to the activation of inflammatory factors after alcohol-induced liver injury. In addition, alcohol can induce apoptosis, and knockdown of CRNDE can reduce apoptosis. Our integrated expression profiling identified CRNDE independently associated with ALD. CRNDE can facilitate inflammation and apoptosis in ALD.

Alcohol's Impact on the Gut and Liver

Alcohol is inextricably linked with the digestive system. It is absorbed through the gut and metabolised by hepatocytes within the liver. Excessive alcohol use results in alterations to the gut microbiome and gut epithelial integrity. It contributes to important micronutrient deficiencies including short-chain fatty acids and trace elements that can influence immune function and lead to liver damage. In some people, long-term alcohol misuse results in liver disease progressing from fatty liver to cirrhosis and hepatocellular carcinoma, and results in over half of all deaths from chronic liver disease, over half a million globally per year. In this review, we will describe the effect of alcohol on the gut, the gut microbiome and liver function and structure, with a specific focus on micronutrients and areas for future research.

Autophagy Inhibition Plays a Protective Role in Ferroptosis Induced by Alcohol via the p62-Keap1-Nrf2 Pathway

Binge alcohol consumption is a serious health concern. Ferroptosis is an iron-dependent lipid peroxidation mediated cell death. Activation of the Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) pathway has been shown to exert a protective effect by blunting the responses to ferroptosis inducers. The autophagy substrate p62 was demonstrated to modulate Nrf2 and contribute to the suppression of ferroptosis. Furthermore, autophagy inhibition resulted in the accumulation of p62, which is a specific substrate for this process. Therefore, we aimed to explore the protective effect of autophagy inhibition against alcohol-induced ferroptosis through activating the p62-Keap1-Nrf2 pathway. Our results demonstrated that alcohol induced ferroptosis, which could be significantly reduced by ferrostatin-1. Additionally, we found that autophagy inhibition could protect HepG2 cells against alcohol-induced ferroptosis by activating the p62-Keap1-Nrf2 pathway. Furthermore, inhibition of autophagy increased the expression of p62, which interacted with Keap1 to promote Nrf2 translocation into the nucleus and upregulation its target proteins ferritin heavy (FTH), ferroportin (FPN), and heme oxygenase-1 (HO-1). This study provides a theoretical basis for further elucidation of the relationship between autophagy and ferroptosis and lays a preliminary foundation for further research concerning dietary guidance in the prevention and treatment of diseases related to alcohol-induced ferroptosis.

The molecular mechanism of acute liver injury and inflammatory response induced by Concanavalin A

Acute liver injury is a common but urgent clinical condition, and its underlying mechanism remains to be further elucidated. Concanavalin A (ConA)-induced liver injury was investigated in the study. Different from the caspase-dependent cell apoptosis in lipopolysaccharide/D-aminogalactose (LPS/D-GalN) induced liver injury, ConA-induced hepatocyte death was independent on caspase. Increased hepatocytic expressions of mixed lineage kinase domain like (MLKL) and receptor-interacting protein kinase 1 (RIPK1), and higher serum concentration of tumor necrosis factor-α (TNF-α) were noticed in mice with ConA-induced liver injury. Inhibition of RIPK1 protein or deletion of MLKL gene could significantly attenuate the acute liver injury and improve mice survival. Besides, the ConA treatment induced severe hepatic inflammation in wide type (WT) mice in comparison with Mlkl-/- mice, suggesting the RIPK1-MLKL-mediated hepatocellular necroptosis might participate in the process of liver injury. Moreover, mitochondrial damage associated molecular patterns (DAMPs) were subsequently released after the hepatocyte death, and further activated the p38 mitogen-activated protein kinase (MAPK) pathway, which could be reduced by deletion or inhibition of Toll-like receptor 9 (TLR9). Taken together, our research revealed that ConA-induced acute liver injury was closely related to TNF-α-mediated cell necroptosis, and inhibiting RIPK1 or deleting MLKL gene could alleviate liver injury in mice. The mitochondrial DNA released by dead hepatocytes further activated neutrophils through TLR9, thus resulting in the exacerbation of liver injury.

The Impact of the NLRP3 Pathway in the Pathogenesis of Non-Alcoholic Fatty Liver Disease and Alcohol-Related Liver Disease

The presence of hepatic steatosis and inflammation is increasingly associated with both metabolic and alcohol-related liver conditions. Both are on the increase globally and, apart from liver transplantation, there are no licensed therapies that target the full complement of disease features. The presence of some shared pathogenic mechanisms and histological features in NAFLD and ALD suggests that it may be possible to develop markers for prognostication or staging, or indeed new therapeutic tools to treat both conditions. One such example of an approach exists in the form of the NACHT-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome pathway. Activation of the NLRP3 inflammasome results in hepatocyte pyroptosis, persistence, and amplification of liver inflammation and activation of profibrogenic signaling cascades. Thus, targeting elements of the pathway in NAFLD and ALD may provide a tractable route to pharmacological therapy. In this review, we summarize the contribution of this inflammasome to disease and review the current options for therapy.

Identification of a MicroRNA-E3 Ubiquitin Ligase Regulatory Network for Hepatocyte Death in Alcohol-Associated Hepatitis

We aimed to identify a microRNA (miRNA)-E3 ubiquitin ligase regulatory network for protein substrates enriched in cell death pathways and investigate the underlying molecular mechanisms in alcohol-associated hepatitis (AH). An miRNA-E3 ubiquitin ligase regulatory network for protein substrates enriched in cell death pathways was constructed using integrated bioinformatics analysis. Differentially expressed hub miRNAs (GSE59492) and their validated miRNA target genes (GSE28619) were identified in the liver of patients with AH compared with healthy controls. Liver samples from patients with AH and healthy individuals and mice exposed to Gao-binge (acute on chronic) ethanol were used for experimental validation. Using hub miRNAs identified by weighted correlation network analysis, a miRNA-E3 ubiquitin ligase regulatory network was established based on 17 miRNAs and 7 E3 ligase genes targeted by these miRNAs that were down-regulated in AH. Among the miRNAs in this regulatory network, miR-150-5p was the only miRNA regulating the E3 ligase cytokine-inducible SH2 containing protein (CISH), the E3 ligase that regulates the largest number of substrates among all E3 ligase family members. Therefore, the CISH regulatory pathway for ubiquitinated substrates was selected for subsequent experimental validation. Consistent with the bioinformatics analysis results, expression of miR-150-5p was markedly increased, while CISH was decreased, in the livers of patients with AH and mice exposed to Gao-binge ethanol. Moreover, ubiquitination of Fas-associated protein with death domain, a predicted CISH substrate involved in the regulation of programmed cell death, was reduced in livers from mice after Gao-binge ethanol. Conclusion: Identification of the miRNA-E3 ubiquitin ligase regulatory network for protein substrates enriched in the cell death pathways provides insights into the molecular mechanisms contributing to hepatocyte death in AH.

Network Meta-Analysis on the Mechanisms Underlying Alcohol Augmentation of COVID-19 Pathologies

Background

The coronavirus disease 2019 (COVID‐19) pandemic is a worldwide crisis caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). Many COVID‐19 patients present with fever in the early phase, with some progressing to a hyperinflammatory phase. Ethanol (EtOH) exposure may lead to systemic inflammation. Network meta‐analysis was conducted to examine possible relationships between EtOH consumption and COVID‐19 pathologies.

Methods

Molecules affected by EtOH exposure were identified by analysis with QIAGEN Knowledge Base. Molecules affected by COVID‐19 were identified from studies in MEDLINE, bioRxiv, and medRxiv reporting gene expression profiles in COVID‐19 patients, QIAGEN Coronavirus Network Explorer, and analysis of the RNA‐sequencing data of autopsied lungs of COVID‐19 patients retrieved from the GEO database. Network meta‐analysis was then conducted on these molecules using QIAGEN Ingenuity Pathway Analysis (IPA).

Results

Twenty‐eight studies reporting significant gene expression changes in COVID‐19 patients were identified. One RNA‐sequencing dataset on autopsied lungs of COVID‐19 patients was retrieved from GEO. Our network meta‐analysis suggests that EtOH exposure may augment the effects of SARS‐CoV‐2 infection on hepatic fibrosis signaling pathway, cellular metabolism and homeostasis, inflammation, and neuroinflammation. EtOH may also enhance the activity of key mediators including cytokines, such as IL‐1β, IL‐6, and TNF, and transcription factors, such as JUN and STAT, while inhibiting the activity of anti‐inflammatory mediators including glucocorticoid receptor. Furthermore, IL‐1β, IL‐6, TNF, JUN, and STAT were mapped to 10 pathways predicted to associate with SARS‐CoV‐2 proteins, including HMGB1, IL‐1, and IL‐6 signaling pathways.

Conclusions

Our meta‐analyses demonstrate that EtOH exposure may augment SARS‐CoV‐2–induced inflammation by altering the activity of key inflammatory mediators. Our findings suggest that it is important for clinicians to caution patients about the risk of alcohol consumption, which has increased during the COVID‐19 pandemic. The findings also call for further investigation into how alcohol exposure affects viral infections.

A review on molecular mechanism of alcoholic liver disease

Excessive alcohol consumption leads to damage to the organs of the body. More importantly, the liver is majorly affected organ upon alcohol consumption for most of the people; it causes inflammation and affects various pathways involved in metabolism. If the person is with high response of inflammatory in conduct with alcohol leads to the liver damage, which involves the creating effects with major cycle leads to homeostasis. In this review, we summarize the molecular mechanisms of alcoholic liver disease, such as the important role of genes, risk factors, pathogenicity, and role of micro RNA, the role of inflammation in the liver, and alcoholic fibrosis in the liver. There is increased oxidative stress, change in the biochemical alterations, and reduction in the antioxidant enzymes. These changes in the mechanism lead to liver injury. Hepatocyte nuclear factor-4 is the major transcriptional factor for the regulation of some genes involved in the lipid metabolism and oxidation process; with the help of the agonist, we can attenuate the level of the gene in the site of hepatic tissues, which will prevent the homeostatic condition. This review shows a clear view of the various pathways involved in alcohol consumption, which helps in the prevention of ALD using an agonist.

A narrative review of the role of necroptosis in liver disease: a double-edged sword

Acute and chronic liver injuries lead to hepatocyte death and turnover. When injuries become chronic, continuous cell death and transformation lead to chronic inflammation, fibrosis, cirrhosis, and eventually carcinoma. A therapeutic strategy of great significance for liver disease is to control hepatocyte death in acute and chronic injuries. This strategy prevents hepatocytes from causing liver failure and inhibits both secondary inflammation and fibrosis. Both apoptosis and necrosis have been proven to occur in the liver, but the role of necroptosis in liver diseases is controversial. Necroptosis, which has features of necrosis and apoptosis, is a regulatory process that occurs in some cell types when caspases are inhibited. The signaling pathway of necroptosis is characterized by the activation of receptor-interacting proteins kinase (RIPK) and mixed lineage kinase domain-like (MLKL). Necroptosis is associated with a variety of inflammatory diseases and has been the focus of research in recent years. The incidence of necroptosis in liver tissues has been studied recently in several liver injury models, but the results of the studies are not consistent. The purpose of this review is to summarize the published data on the involvement of necroptosis in liver injury, focusing on the controversies, issues remaining to be discussed, and potential therapeutic applications in this area.

MANF protects pancreatic acinar cells against alcohol-induced endoplasmic reticulum stress and cellular injury

BACKGROUND/PURPOSE

Heavy alcohol drinking is associated with pancreatitis. Pancreatitis is initiated by the damage to the pancreatic acinar cells. The endoplasmic reticulum (ER) stress has been shown to play an important role in alcohol-induced pancreatic damage. Mesencephalic astrocyte-derived neurotrophic factor (MANF) is an ER stress-inducible protein. The aim of the study was to determine whether MANF can ameliorate alcohol-induced ER stress and cellular damages to pancreatic acinar cells.

METHODS

Alcohol-induced damage to mouse pancreatic 266-6 acinar cells was determined by MTT and flow cytometry. MANF expression was downregulated by MANF siRNA using the Neon Transfection System. The overexpression of MANF was performed by the infection with the adenoviral vector carrying mouse MANF gene. The expression of ER stress markers was determined by immunoblotting and immunofluorescence.

RESULTS

Alcohol caused ER stress, oxidative stress and induced apoptosis of 266-6 acinar cells. Recombinant human MANF alleviated alcohol-induced ER stress and cell death by inhibiting IRE1-caspase 12-caspase 3 apoptotic pathway. Overexpression of mouse MANF also protected cells against alcohol-induced apoptosis. In contrast, inhibiting MANF by siRNA exacerbated alcohol-induced cellular damage.

CONCLUSIONS

MANF was protective against alcohol-induced ER stress and cellular injury in pancreatic acinar cells. The findings suggest a potential therapeutic value of MANF for alcoholic pancreatitis.

Phosphorylation of eIF2α mitigates endoplasmic reticulum stress and hepatocyte necroptosis in acute liver injury

INTRODUCTION AND OBJECTIVES

Necroptosis and endoplasmic reticulum (ER) stress has been implicated in acute and chronic liver injury. Activated eukaryotic initiation factor 2 alpha (eIF2α) attenuates protein synthesis and relieves the load of protein folding in the ER. In this study, we aimed to analyze the impact of eIF2α phosphorylation on hepatocyte necroptosis in acute liver injury.

MATERIALS AND METHODS

Male BALB/c mice were injected with tunicamycin or d-galactosamine, and LO2 cells were incubated with tunicamycin to induce acute liver injury. 4-Phenylbutyric acid (PBA) and salubrinal were used to inhibit ER stress and eIF2α dephosphorylation, respectively. We analyzed the eIF2α phosphorylation, ER stress, and hepatocyte necroptosis in mice and cells model.

RESULTS

Tunicamycin or d-galactosamine significantly induced ER stress and necroptosis, as well as eIF2α phosphorylation, in mice and LO2 cells (p<0.05). ER stress aggravated tunicamycin-induced hepatocyte necroptosis in mice and LO2 cells (p<0.05). Elevated eIF2α phosphorylation significantly mitigated hepatocyte ER stress (p<0.05) and hepatocyte necroptosis in mice (34.37±3.39% vs 22.53±2.18%; p<0.05) and LO2 cells (1±0.11 vs 0.33±0.05; p<0.05). Interestingly, tumor necrosis factor receptor (TNFR) 1 protein levels were not completely synchronized with necroptosis. TNFR1 expression was reduced in d-galactosamine-treated mice (p<0.05) and cells incubated with tunicamycin for 12 and 24h (p<0.05). ER stress partially restored TNFR1 expression and increased necroptosis in tunicamycin-incubated cells (p<0.05).

CONCLUSIONS

These results imply that ER stress can mediate hepatocyte necroptosis independent of TNFR1 signaling and elevated eIF2α phosphorylation can mitigate ER stress during acute liver injury.

Cell Death in Liver Diseases: A Review

Regulated cell death (RCD) is pivotal in directing the severity and outcome of liver injury. Hepatocyte cell death is a critical event in the progression of liver disease due to resultant inflammation leading to fibrosis. Apoptosis, necrosis, necroptosis, autophagy, and recently, pyroptosis and ferroptosis, have all been investigated in the pathogenesis of various liver diseases. These cell death subroutines display distinct features, while sharing many similar characteristics with considerable overlap and crosstalk. Multiple types of cell death modes can likely coexist, and the death of different liver cell populations may contribute to liver injury in each type of disease. This review addresses the known signaling cascades in each cell death pathway and its implications in liver disease. In this review, we describe the common findings in each disease model, as well as the controversies and the limitations of current data with a particular focus on cell death-related research in humans and in rodent models of alcoholic liver disease, non-alcoholic fatty liver disease and steatohepatitis (NASH/NAFLD), acetaminophen (APAP)-induced hepatotoxicity, autoimmune hepatitis, cholestatic liver disease, and viral hepatitis.

Gentiopicroside prevents alcoholic liver damage by improving mitochondrial dysfunction in the rat model

Gentianae Radix et Rhizoma is a medical plant that is widely cultivated in China, North Korea, Japan, and Russia, and gentiopicroside is one of its major active compounds. In this study, the hepatoprotective activity of gentiopicroside on rats with alcoholic liver damage (ALD) was evaluated using the transaminase and blood lipid levels and antioxidant capacity. The potential mechanism of hepatoprotective effect of gentiopicroside was evaluated by mitochondrial function detection, gas chromatography-mass spectrometry (GC-MS) metabolomic analysis, and anti-apoptosis analysis. Results showed that the gentiopicroside exhibited good hepatoprotective activity on rats with ALD by decreasing the transaminase levels, regulating the blood lipid levels, and increasing the antioxidant capacity. The potential mechanisms were related to regulating mitochondrial dysfunction by recovering mitochondrial membrane potential level, adenosine triphosphate concentration, activities of key enzymes in tricarboxylic acid cycle, and activities of complex I-V, regulating micromolecular metabolism and anti-apoptosis. These findings supported the further exploration of Gentianae Radix et Rhizoma as effective phytotherapy to prevent and treat ALD.

Physcion Protects Against Ethanol-Induced Liver Injury by Reprogramming of Circadian Clock

The circadian clock plays a key role in our daily physiology and metabolism. Alcohol consumption disrupts the circadian rhythm of metabolic genes in the liver; however, the potential contribution of circadian clock modulation to alcoholic liver disease (ALD) is unknown. We identified a novel liver protective agent, physcion, which can alleviate fat accumulation and inflammation in ALD mice via reprogramming the hepatic circadian clock. The model of alcoholic hepatitis was established by intragastrically administering ethanol. In vitro, physcion was investigated by treating HepG2 cells with ethanol. The role of circadian clock in Physcion caused liver protection was tested by knocking down the core circadian gene Bmal1. Physcion application caused reduced lipogenesis and alleviated inflammation in alcohol-induced mice. In alcoholic hepatosteatosis models, physcion upregulated the core circadian genes. And the circadian misalignment triggered by ethanol was efficiently reversed by physcion. Physcion attenuated lipogenesis via reprogramming the circadian clock in HepG2 cells. Suppression of Bmal1 by RNA interference abolished the protective of physcion. In addition, Physcion binds to the active pocket of BMAL1 and promotes its expression. The study identified the novel liver protective effects of physcion on alcohol-induced liver injury, and modulation of the core circadian clock regulators contributes to ALD alleviation. More importantly, strategies targeting the circadian machinery, for example, Bmal1, may prove to be beneficial treatment options for this condition.

NLRP12 negatively regulates EtOH-induced liver macrophage activation via NF-κB pathway and mediates hepatocyte apoptosis in alcoholic liver injury

Alcohol-induced liver injury is characterized by abnormal liver dysfunction and excessive inflammation response. Recent years a wealth of data have been yielded indicating that EtOH (ethyl alcohol)-induced macrophage activation along with liver inflammation plays a dominating role in the progression of alcohol-induced liver injury. Here we found high expression of NLRP12 (Nucleotide-binding oligomerization domain protein 12, which is generally considered to be a negative regulator of inflammatory response) in EtOH-fed mouse liver tissue, primary Kupffer cells and EtOH-induced RAW264.7 cells. Additionally, overexpression of NLRP12 following Ad (adenovirus)-NLRP12-EGFP contributed to the attenuation of steatosis and inflammation in EtOH-fed mice model and EtOH-primed RAW264.7 cells. In parallel, Knockdown of NLRP12 aggravated the inflammatory response in RAW264.7 cells triggered by EtOH. Meanwhile, after administration of overexpression or inhibition of NLRP12 expression in vitro, the expression of phosphorylated protein of NF-kB signaling pathway was significantly affected. After increasing or decreasing the expression of NLRP12 in RAW264.7 cells, AML-12 cells were cultured with the supernatant of RAW264.7 cells stimulated by EtOH, and the percent of apoptosis ratio of AML-12 cells was remarkably altered. The study suggested that reduced inflammatory response induced by NLRP12-mediated inhibition of NF-kB pathway participated in the decrease of hepatocyte apoptosis in alcohol-induced liver injury. Collectively, these findings suggested the significance of NLRP12-mediated macrophage activation in alcohol-induced liver injury.