Project description:Nicotinamide mononucleotide adenylyltransferase 1 (NMNAT1), an NAD+ synthetase in Preiss-Handler and salvage pathways, governs nuclear NAD+ homeostasis. This study investigated the role of NMNAT1 on alcohol-associated liver disease (ALD). Decreased NMNAT1 expression and activity were observed in the liver of alcohol-associated hepatitis patients and either liver or primary hepatocytes from ALD mice. F-box and WD repeat domain containing 7 (FBXW7)-regulated interferon regulatory factor 1 (IRF1) ubiquitination degradation contributed to alcohol-inhibited NMNAT1 transcriptional level. Hepatic NMNAT1 knockout aggravated alcohol-induced hepatic NAD+ decline and further hepatic steatosis and liver injury. Metabolomics and transcriptomics interaction revealed that cysteine sulfinic acid decarboxylase (CSAD)-regulated taurine pathway was involved in NMNAT1-disrupted hepatic lipid metabolism in ALD. Hepatic CSAD overexpression or taurine supply attenuated hepatic NMNAT1 knockout-aggravated ALD, respectively. Hepatic NMNAT1 loss inhibited NMN-protected ALD. Replenishing hepatic NMNAT1 reversed liver lipid accumulation in ALD mice. These findings identified NMNAT1 as a promising therapeutic target for ALD.
Project description:Background and Aims: Alcohol-related liver disease (ALD) is one of the leading causes of severe liver disease with limited pharmacological treatments for alcohol-related steatohepatitis (ASH). CD44, a glycoprotein mainly expressed in immune cells, has been implicated in multiple inflammatory diseases but has never been studied in the ALD context. We therefore studied its contribution to ASH development in mice and its expression in ALD patients. Approach and Results: Here, we report that liver CD44 expression is associated with liver injury and inflammation and its deficiency (Cd44-/-) partially protected mice upon chronic plus binge ethanol feeding (CPB-EtOH). CD44 deletion in myeloid cells (Cd44myel-KO) recapitulated the same protective effects associated with reduced inflammatory monocyte infiltration and neutrophil activation in the liver and diminished blood neutrophil-lymphocyte ratio (NLR). CD44-deficient neutrophils displayed reduced PMA-induced inflammatory mediator expression and increased phagocytosis of live bacteria. Cd44myel-KO mice were also protected against hepatic steatosis mediated by CPB-EtOH or chronic ethanol feeding, due in part to increased SIRT1 mediated fatty acid beta-oxidation. CD44 neutralization with antibodies strongly decreased liver injury and inflammation (hepatic neutrophil frequency) and blood NLR upon CPB-EtOH. In samples from ALD patients, hepatic CD44 expression increased with ALD severity, correlated with hepatic TNFα and CD11b expression, and CD44-expressing neutrophils were enriched in alcohol-associated hepatitis. Conclusions: Human and experimental evidence supports CD44 as a marker of hepatic inflammation in ALD. In addition, CD44 modulates neutrophil mobilization and functions and its targeting partially prevents liver inflammation and injury in the context of acute-on-chronic alcohol drinking.
Project description:Background and Aims: Alcohol-related liver disease (ALD) is one of the leading causes of severe liver disease with limited pharmacological treatments for alcohol-related steatohepatitis (ASH). CD44, a glycoprotein mainly expressed in immune cells, has been implicated in multiple inflammatory diseases but has never been studied in the ALD context. We therefore studied its contribution to ASH development in mice and its expression in ALD patients. Approach and Results: Here, we report that liver CD44 expression is associated with liver injury and inflammation and its deficiency (Cd44-/-) partially protected mice upon chronic plus binge ethanol feeding (CPB-EtOH). CD44 deletion in myeloid cells (Cd44myel-KO) recapitulated the same protective effects associated with reduced inflammatory monocyte infiltration and neutrophil activation in the liver and diminished blood neutrophil-lymphocyte ratio (NLR). CD44-deficient neutrophils displayed reduced PMA-induced inflammatory mediator expression and increased phagocytosis of live bacteria. Cd44myel-KO mice were also protected against hepatic steatosis mediated by CPB-EtOH or chronic ethanol feeding, due in part to increased SIRT1 mediated fatty acid beta-oxidation. CD44 neutralization with antibodies strongly decreased liver injury and inflammation (hepatic neutrophil frequency) and blood NLR upon CPB-EtOH. In samples from ALD patients, hepatic CD44 expression increased with ALD severity, correlated with hepatic TNFα and CD11b expression, and CD44-expressing neutrophils were enriched in alcohol-associated hepatitis. Conclusions: Human and experimental evidence supports CD44 as a marker of hepatic inflammation in ALD. In addition, CD44 modulates neutrophil mobilization and functions and its targeting partially prevents liver inflammation and injury in the context of acute-on-chronic alcohol drinking.
Project description:Metabolic dysfunction-associated steatotic liver disease and its progressive and inflamma-tory form metabolic dysfunction-associated steatohepatitis represents a global health challenge, with limited treatment options available. In this study we identified an endoge-nous, understudied omega-6 fatty acid metabolite, arachidonoyl-taurine (ARA-T), capable of mitigating liver disease. ARA-T levels increased in human plasma of chronic and acute fatty liver and their abundance can be driven in humans and mice by dietary supplementa-tion of arachidonic acid. Surprisingly, our genetic model of elevated circulating ARA-T levels prevented inflammation and hepatic steatosis by increased uptake and turnover of fatty ac-ids in the liver. Pharmacological administration of ARA-T reduced liver weight and diet-induced hepatic lipid deposition in mice, demonstrating its potential to protect against and reverse the progression of liver disease. Thus, ARA-T may represent a way to protect against pro-inflammatory actions of omega-6 fatty acids thereby contributing to regulation of in-flammation and accumulation of hepatic lipids.
Project description:Metabolic dysfunction-associated steatotic liver disease and its progressive and inflamma-tory form metabolic dysfunction-associated steatohepatitis represents a global health challenge, with limited treatment options available. In this study we identified an endoge-nous, understudied omega-6 fatty acid metabolite, arachidonoyl-taurine (ARA-T), capable of mitigating liver disease. ARA-T levels increased in human plasma of chronic and acute fatty liver and their abundance can be driven in humans and mice by dietary supplementa-tion of arachidonic acid. Surprisingly, our genetic model of elevated circulating ARA-T levels prevented inflammation and hepatic steatosis by increased uptake and turnover of fatty ac-ids in the liver. Pharmacological administration of ARA-T reduced liver weight and diet-induced hepatic lipid deposition in mice, demonstrating its potential to protect against and reverse the progression of liver disease. Thus, ARA-T may represent a way to protect against pro-inflammatory actions of omega-6 fatty acids thereby contributing to regulation of in-flammation and accumulation of hepatic lipids.
Project description:Metabolic dysfunction-associated steatotic liver disease and its progressive and inflamma-tory form metabolic dysfunction-associated steatohepatitis represents a global health challenge, with limited treatment options available. In this study we identified an endoge-nous, understudied omega-6 fatty acid metabolite, arachidonoyl-taurine (ARA-T), capable of mitigating liver disease. ARA-T levels increased in human plasma of chronic and acute fatty liver and their abundance can be driven in humans and mice by dietary supplementa-tion of arachidonic acid. Surprisingly, our genetic model of elevated circulating ARA-T levels prevented inflammation and hepatic steatosis by increased uptake and turnover of fatty ac-ids in the liver. Pharmacological administration of ARA-T reduced liver weight and diet-induced hepatic lipid deposition in mice, demonstrating its potential to protect against and reverse the progression of liver disease. Thus, ARA-T may represent a way to protect against pro-inflammatory actions of omega-6 fatty acids thereby contributing to regulation of in-flammation and accumulation of hepatic lipids.
Project description:The tumor suppressor p53 is critical for tumor suppression and other biological events. Yet, the regulatory role of p53 in alcohol-induced fatty liver remains unclear. Here, we show a role for p53 in regulating the ethanol metabolism via acetaldehyde dehydrogenase 2 (ALDH2), a key enzyme responsible for oxidization of alcohol. Through repressing ethanol oxidization, p53 suppresses intracellular levels of acetyl-CoA and histone acetylation, leading to the inhibition of the stearoyl-CoA desaturase-1 (SCD1) gene expression. Mechanistically, p53 directly binds to ALDH2 and prevents the formation of its active tetramer, and indirectly limits the production of pyruvate that promotes the activity of ALDH2. Notably, p53 deficient mice exhibit increased lipid accumulation, which can be reversed by ALDH2 depletion. Moreover, hepatic specific knockdown of SCD1 diminishes ethanol-induced fatty liver caused by p53 loss. By contrast, overexpression of SCD1 in liver promotes ethanol-induced fatty liver development in wildtype mice, while has mild effect on p53-/- or ALDH2-/- mice. Overall, our findings reveal a previously unrecognized function of p53 in alcohol-induced fatty liver, and uncover pyruvate as a natural regulator of ALDH2.
Project description:To investigate the function of read-through circRNAs in liver, we obtained human NASH liver tissues and normal liver tissues patients without NAFLD undergoing surgery for hepatic hemangioma.Patients with positive hepatitis B surface antigen or anti-hepatitis C virus (HCV) antibody with detectable HCV RNA, excessive alcohol consumption (20 g/day in men or 10 g/day in women), secondary fatty liver (e.g., use of systemic steroids or tamoxifen), or malignancies before baseline were excluded. We then performed exome capture mRNA sequencing using livers from three NASH patients and three patients with hepatic hemangioma.
Project description:Alcohol induced fatty liver cause a dangerous health problem and is the major cause of morbidity and mortality worldwide. Garlic (Allium sativum) is documented to possess anti-fatty liver properties. However the exact molecular mechanisms are unknown. The main aim of this experiment is to elucidate the underlying pathways through which garlic ameliorates alcohol induced fatty liver. Dially disulfide and garlic oil were the garlic compounds used in this study. Leiber DeCarli ethanol liquid diet was to induce fatty liver in C57BL/6 mice model. Also the expression impaired by alcohol induced fatty liver is another aim of this study.
Project description:Alcoholic liver diseases (ALDs) encompass a broad spectrum of clinical features of alcoholic fatty liver, alcoholic steatohepatitis and cirrhosis, and increased risk of hepatocellular carcinoma. While the toxic effects of alcohol likely result from complex interactions between genes and the environment, the molecular mechanisms of alcohol-induced liver damage remains undefined. Thus, a better understanding of the mechanisms regulating hepatic cell injury may lead to more effective therapeutic approaches for ALD. Here we compared the miRNA expression profile from tissues from control mice and mice receiving intragastric ethanol feeding. Four microarray hybridization studies were performed on three different pairs of liver-derived RNA from intragastric ethanol feeding and normal mice. The miRNAs differentially overexpressed in livers from ethanol fed mice.