NIAAA Model Research Articles

Phospholipase D2 drives cellular lipotoxicity and tissue inflammation in alcohol-associated liver disease

AimsExcessive alcohol consumption leads to alcoholic liver disease (ALD), a major contributing factor to cirrhosis and hepatocellular carcinoma. In the present study we investigated the involvement of phospholipase D2 (PLD2) in the pathogenesis of ALD. Methods and materialsALD was induced in mice by chronic and binge ethanol feeding (the NIAAA model). Cellular transcriptome was examined by RNA-seq. Key findingsAnalysis of RNA-seq datasets indicated that PLD2 expression was up-regulated in liver tissues and in hepatocytes during ALD pathogenesis. Exposure of hepatocytes to ethanol treatment led to an increase in PLD2 expression. Similarly, ethanol feeding in mice stimulated PLD2 expression in the liver. On the contrary, PLD2 knockdown in hepatocytes down-regulated expression of pro-inflammatory and pro-lipogenic genes and dampened lipid accumulation. Consistently, PLD2 knockdown in mice significantly ameliorated ALD pathogenesis as evidenced by reduced steatosis and hepatic inflamamation. RNA-seq identified several metabolic pathways that were influenced by PLD2 deficiency. SignificanceOur data demonstrate that PLD2 is a novel regulator of ALD and suggest that small-molecule PLD2 inhibitors can be considered as a reasonable strategy for ALD treatment.

Protective effects of phenylethanol glycosides from Cistanche tubulosa against ALD through modulating gut microbiota homeostasis

Ethnopharmacological relevanceCistanche tubulosa (Schenk) Wight, a Chinese herbal medicine (Rou Cong Rong) with Xinjiang characteristics, was recorded in many medical books in ancient China and often used as a tonic medicine. Supported by the traditional Chinese medicine theory of “homology of liver and kidney,” C. tubulosa (Schenk) Wight has many clinical applications in tonifying the kidney and protecting the liver. Modern pharmacological studies have also found that the protective effects of phenylethanol glycosides from C. tubulosa (Schenk) Wight (CPhGs) play an important role in ameliorating alcoholic liver injury. Aim of the studyWe aimed to investigate whether CPhGs can enhance the therapeutic outcome of alcoholic liver disease (ALD) by targeting the “gut–liver axis,” thus contributing to the knowledge of how Chinese herbs alleviate disease by influencing the gut microbiota. Materials and methodsAn ALD mouse model was established using the Lieber–DeCarli alcohol liquid diet, and the effects of CPhGs on the intestinal barrier and gut microbiota of ALD mice were investigated in a pseudo-sterile mouse model and fecal microbiota transplantation (FMT) mouse model. We fed female C57BL/6N mice with Lieber-DeCarli ethanol liquid diet, according to the NIAAA model. Animal experiment of long-term, ethanol diet intervention for 6W, and short-term for 11d. The FMT experiments were also performed. ResultsCPhGs significantly improved ALD manifestations. ALD mice demonstrated significant gut microbiota dysbiosis and significantly abnormal proliferation of Allobaculum compared with the control diet group in long-term NIAAA mouse model (L-Pair). In mice that received the long-term intervention, the improvement in gut barrier function in the CPhGs-treated group was accompanied by a significant decrease in the abundance of Allobaculum and a significant increase in the abundance of Akkermansia. Furthermore, compared with the mouse were gavaged fecal microbiota from the long-term NIAAA mouse donors (FMT-EtOH), the number of goblet cells, abundance of Akkermansia, and the intestinal short-chain fatty acid concentrations were significantly increased in the mouse were gavaged fecal microbiota from high (700 mg/kg) doses of CPhGs orally in long-term NIAAA model donors (FMT-EtOH-H). Network analysis and species distribution results demonstrated that Akkermansia and Allobaculum were the genera with the highest abundances in the gut microbiota and that their interaction was related to propionic acid metabolism. ConclusionsThe results suggest that CPhGs exert a protective effect against ALD by modulating the abundance and composition of Akkermansia and Allobaculum in the intestine, maintaining the intestinal mucus balance, and safeguarding intestinal barrier integrity.

Involvement of BRD4 in Alcoholic Liver Injury: Autophagy Modulation via Regulation of the SIRT1/Beclin1 Axis

Alcoholic liver disease (ALD) caused by chronic alcohol abuse involves complex processes from steatosis to fibrosis, cirrhosis, and hepatocellular carcinoma, posing a global health issue. Bromodomain protein 4 (BRD4) typically serves as a “reader” modulating the functions of transcription factors involved in various biological processes and disease progression. However, the specific mechanisms underlying alcoholic liver injury remain unclear. In this study, we detected aberrant BRD4 expression in the alcohol-induced ALD mouse model of chronic and binge ethanol feeding developed by the National Institute on Alcohol Abuse and Alcoholism, consistent with the in vitro results in Aml-12 mouse hepatocytes. Blocking and inhibiting BRD4 restored the impaired autophagic flux and lysosomal functions in alcohol-treated Aml-12 cells, whereas BRD4 overexpression reduced the expression levels of autophagy marker and lysosomal genes. Furthermore, mouse BRD4 knockdown, mediated by a short hairpin RNA carried by the adeno-associated virus serotype 8, significantly attenuated the alcohol-induced hepatocyte damage, including lipid deposition and inflammatory cell infiltration. Mechanistically, BRD4 overexpression in alcoholic liver injury inhibited the expression of sirtuin (SIRT)1 in Aml-12 cells. Chromatin immunoprecipitation and dual-luciferase reporter assays revealed that BRD4 functions as a transcription factor and suppressor, actively binding to the SIRT1 promoter region and inhibiting its transcription. SIRT1 activated autophagy, which was suppressed in alcoholic liver injury via Beclin1 deacetylation. In conclusion, our study revealed that BRD4 negatively regulated the SIRT1/Beclin1 axis and that its deficiency alleviated alcohol-induced liver injury in mice, thus providing a new strategy for ALD treatment.

Clinical characteristics and prognosis of hospitalized patients with moderate alcohol-associated hepatitis.

Little is known about the clinical characteristics and prognosis of hospitalized patients with moderate alcohol-associated hepatitis (mAH) as compared to severe alcohol-associated hepatitis (sAH). Therefore, we aimed to describe the clinical characteristics and risk factors associated with mortality in hospitalized mAH patients. Patients hospitalized with alcohol-associated hepatitis (AH) from 1 January 2010 to 31 December 2020 at a large US healthcare system [11 hospitals, one liver transplant centre] were retrospectively analysed for outcomes. Primary outcome was 90-day mortality. AH and mAH were defined according to NIAAA Alcoholic Hepatitis Consortia and Model for End-stage Liver Disease Score ≤ 20 respectively. Multivariable Cox regression analysis was performed to identify independent risk factors associated with 90-day mortality. 1504 AH patients were hospitalized during the study period, of whom 39% (n = 590) had mAH. Compared to sAH patients, mAH patients were older (50 vs. 48 years, p < 0.001) and less likely to have underlying cirrhosis (74% vs. 83%, p < 0.001). There were no differences between the two groups for median alcohol intake g/day (mAH 140.0 vs. sAH 112.0, p = 0.071). The cumulative proportion surviving at 90 days was 88% in mAH versus 62% in sAH (p < 0.001). On multivariable analysis, older age [HR 1.03 (95% CI 1.00-1.06), p = 0.020], corticosteroid use [HR 1.80 (95% CI 1.06-3.06), p = 0.030] and acute kidney injury (AKI) [HR 2.43 (95% CI 1.33-4.47), p = 0.004] were independently associated with 90-day mortality. mAH carries a 12% mortality rate at 90 days. Age, AKI and corticosteroid use were associated with an increased risk for 90-day mortality. Avoidance of corticosteroids and strategies to reduce the risk of AKI could improve outcomes in mAH patients.

Akkermansia muciniphila Ameliorates Alcoholic Liver Disease in Experimental Mice by Regulating Serum Metabolism and Improving Gut Dysbiosis.

Alcoholic liver disease (ALD) represents a significant global health concern, yet the available treatment options remain limited. Numerous studies have shown that gut microbiota is a critical target for the treatment of ALD. Additionally, there is increasing evidence that host metabolism also plays a crucial role in the development of ALD. Akkermansia muciniphila has been demonstrated to ameliorate experimental ALD through its modulatory effects on the intestinal vascular barrier, enhancement of mucus layer thickness, and promotion of intestinal tight junction proteins. Nevertheless, there is a dearth of studies investigating the impact of A. muciniphila on host metabolism and gut microbiota. Here, C57BL/6 mice were utilized to establish a modified NIAAA model in order to investigate the impact of the oral administration of A. muciniphila during the development of ALD. Furthermore, we employed targeted metabolomics to analyze the serum metabolomic profiles of the mice and 2bRAD-M sequencing to comprehensively examine the underlying mechanisms of the efficacy of A. muciniphila on ALD. Our results illustrated that the oral administration of A. muciniphila alleviated alcohol-induced liver injury in conjunction with encouraged serum levels of ornithine and diminished the elevation of oxalic acid levels induced by alcohol intake. In addition, A. muciniphila also inhibited the proliferation of harmful bacteria, such as Escherichia coli and Helicobacter hepaticus, induced by alcohol consumption while promoting the growth of butyrate-producing and commensal bacteria, including Paramuribaculum intestinale and Bacteroides ovatus. In conclusion, this study suggests that A. muciniphila restores ALD by regulating the gut microbiota, and this corrective effect is associated with alterations in the serum metabolism. Our research supplies a theoretical basis for developing A. muciniphila as an innovative generation of probiotic for preventing and managing ALD.

Puerarin inhibits inflammation and lipid accumulation in alcoholic liver disease through regulating MMP8.

Alcoholic liver disease (ALD) is a growing global health concern, and its early pathogenesis includes steatosis and steatohepatitis. Inhibiting lipid accumulation and inflammation is a crucial step in relieving ALD. Evidence shows that puerarin (Pue), an isoflavone isolated from Pueraria lobata, exerts cardio-protective, neuroprotective, anti-inflammatory, antioxidant activities. However, the therapeutic potential of Pue on ALD remains unknown. In the study, both the NIAAA model and ethanol (EtOH)-induced AML-12 cell were used to explore the protective effect of Pue on alcoholic liver injury in vivo and in vitro and related mechanism. The results showed that Pue (100 mg·kg-1) attenuated EtOH-induced liver injury and inhibited the levels of SREBP-1c, TNF-α, IL-6 and IL-1β, compared with silymarin (Sil, 100 mg·kg-1). In vitro results were consistent within vivo results. Mechanistically, Pue might suppress liver lipid accumulation and inflammation by regulating MMP8. In conclusion, Pue might be a promising clinical candidate for ALD treatment.

Differences of Lipid Proton Compositions and Fatty Acids Between Alcoholic Fatty Liver and High-Fat Diet Fatty Liver Animal Models: 9.4 T Magnetic Resonance Spectroscopy Study

The objective of this study was to determine differences in chemical compositions according to fat deposition in the liver using an alcoholic fatty liver animal model and a high-fat diet-induced fatty liver animal model. A mouse model of chronic and binge ethanol feeding (NIAAA model), an alcoholic fatty liver model, was used to induce fatty liver according to the study protocol. The NIAAA control group had 15 mice. The NIAAA experimental group was administered with Lieber DeCarli diet powder. The high-fat diet control group was fed a general diet ad libitum. The high-fat diet fatty liver group was induced with a high-fat (60%) diet. Data were acquired by 9.4 T magnetic resonance spectroscopy for each fatty liver animal model. Fatty acids were calculated by quantifying each lipid proton through T2 correction. Difference in lipid proton (LP) for each model was identified with a multivariate statistical method. Mean differences in fatty acids among the four models were compared. The difference in LP composition was insignificant between the high-fat diet control and the experimental group. Orthogonal partial least squares discriminant analysis of the high-fat experimental group and the NIAAA experimental group showed no significant difference in the composition of each LP. However, there was a difference in the value of the composition deposited in the liver between NIAAA control and experimental groups. Comparison of each fatty acid between NIAAA control and experimental groups revealed that poly-unsaturated bond was significantly (p = 0.002) higher in the experimental group than in the control group. There were differences in total lipid and polyunsaturated bonds between NIAAA experimental and control groups. Methylene protons were deposited at lower concentrations whereas diallylic protons were deposited at higher concentrations in the NIAAA experimental group than in the control group.

Hepatic pIgR-mediated secretion of IgA limits bacterial translocation and prevents ethanol-induced liver disease in mice

ObjectiveAlcohol-associated liver disease is accompanied by microbial dysbiosis, increased intestinal permeability and hepatic exposure to translocated microbial products that contribute to disease progression. A key strategy to generate immune protection...

NAD Supplement Alleviates Intestinal Barrier Injury Induced by Ethanol Via Protecting Epithelial Mitochondrial Function.

The epithelial tight junction is an important intestinal barrier whose disruption can lead to the release of harmful intestinal substances into the circulation and cause damage to systemic injury. The maintenance of intestinal epithelial tight junctions is closely related to energy homeostasis and mitochondrial function. Nicotinamide riboside (NR) is a NAD booster that can enhance mitochondrial biogenesis in liver. However, whether NR can prevent ethanol-induced intestinal barrier dysfunction and the underlying mechanisms remain unclear. We applied the mouse NIAAA model (chronic plus binge ethanol feeding) and Caco-2 cells to explore the effects of NR on ethanol-induced intestinal barrier dysfunction and the underlying mechanisms. NAD homeostasis and mitochondrial function were measured. In addition, knockdown of SirT1 in Caco-2 cells was further applied to explore the role of SirT1 in the protection of NR. We found that ethanol increased intestinal permeability, increased the release of LPS into the circulation and destroyed the intestinal epithelial barrier structure in mice. NR supplementation attenuated intestinal barrier injury. Both in vivo and in vitro experiments showed that NR attenuated ethanol-induced decreased intestinal tight junction protein expressions and maintained NAD homeostasis. In addition, NR supplementation activated SirT1 activity and increased deacetylation of PGC-1α, and reversed ethanol-induced mitochondrial dysfunction and mitochondrial biogenesis. These effects were diminished with the knockdown of SirT1 in Caco-2 cells. Boosting NAD by NR alleviates ethanol-induced intestinal epithelial barrier damage via protecting mitochondrial function in a SirT1-dependent manner.

Carnosic acid suppressed the formation of NETs in alcoholic hepatosteatosis based on P2X7R-NLRP3 axis

BackgroundAlcoholic liver disease (ALD) is accompanied by a disruption of lipid metabolism and an inflammatory response in the liver during the process of disease. Carnosic acid (CA), a natural diterpene extracted from Rosmarinus officinalis (rosemary) and Salvia officinalis (sage), has more pharmacological activities, which is known to be useful in the treatment of obesity and acts by regulating energy metabolism. However, the role and regulation mechanism of CA against ALD remain unclear. HypothesisWe hypothesized that CA might improve alcoholic-induced hepatosteatosis. Study design and methodsThe alcoholic liver disease model was established a mouse chronic ethanol feeding by Lieber-DeCarli control liquid feed (10 d) plus a single binge with or without CA administration. AML12 cells were exposed to ethanol for 24 h. Murine peritoneal macrophages (MPM) were stimulated with LPS and ATP. ResultsCA ameliorated lipid accumulation in the liver of mice in the NIAAA model, acting by inhibiting the expression of genes related to lipid synthesis. CA reduced alcohol-induced immune cell infiltration in the liver, and inhibited the activation of P2X7R-NLRP3 inflammasome, meanwhile blocked the formation of NETs in mouse livers tissue. In AML12 cells, CA attenuated the lipid accumulation triggered by ethanol stimulation, which was achieved by inhibiting the expression of SREBP1 and CA reduced the release of inflammatory factor IL-1β by inhibiting the activation of P2X7R-NLRP3. In MPM, IL-1β and HMGB1 were reduced after LPS/ATP stimulation in CA-treated cells and supernatant. ConclusionsCA attenuated alcohol-induced fat accumulation, suppressed the formation of NETs based on P2X7R-NLRP3 axis in mouse livers. Our data indicated that CA exerted hepatoprotective effects, which might be a promising candidate.

Altered ethanol metabolism and increased oxidative stress enhance alcohol-associated liver injury in farnesoid X receptor-deficient mice.

Pharmacological activation of farnesoid X receptor (FXR) ameliorates liver injury, steatosis and inflammation in mouse models of alcoholic liver disease (ALD), but the underlying mechanisms of the protective effect of FXR against ALD remain unclear. To investigate the role of FXR in ALD, we used the NIAAA model of chronic plus binge ethanol feeding in FXR-deficient knockout (FXR KO) mice. Ethanol-mediated liver injury and steatosis were increased in FXR KO mice, while both WT and FXR KO mice consumed the same amount of alcohol. Ethanol feeding induced liver inflammation and neutrophil infiltration that were further increased in FXR KO mice. In addition, collagen accumulation and expression of profibrotic genes were markedly elevated in the liver of alcohol-fed FXR KO compared to wild-type mice, suggesting that ethanol-induced liver fibrosis is enhanced in the absence of FXR. Surprisingly, FXR KO mice showed reduced blood alcohol levels post-binge, while CYP2E1 and ALDH1A1 were upregulated compared to WT mice, suggesting that alcohol metabolism is altered in FXR KO mice. Notably, exacerbated liver injury in FXR KO mice was associated with increased oxidative stress. ALDH1A1 activity was upregulated in FXR-deficient mouse primary hepatocytes, contributing to reactive oxygen species (ROS) generation, in vitro. Finally, using an ALDH1A1 inhibitor, we showed that ALDH1A1 activity is a key contributor to alcohol-induced ROS generation in FXR-deficient hepatocytes, in vitro. ALD pathogenesis in FXR KO mice correlates with altered ethanol metabolism and increased oxidative stress, providing new insights into the protective function of FXR in ALD.

Chronic and Binge Alcohol Ingestion Increases Truncated Oxidized Phosphatidylcholines in Mice Lungs Due to Increased Oxidative Stress.

Heavy alcohol drinking has negative health effects in multiple organs. It predisposes lungs to inflammatory conditions associated with acute lung injury and increased incidence of pneumonia and sepsis, which may lead to death due to acute respiratory distress syndrome in some individuals with alcohol use disorder (AUD). In general, rodent models of alcohol exposure either do not recapitulate multiple organ injuries as seen in humans or require longer duration to establish tissue injury and inflammation. The recently introduced NIAAA model of alcohol-induced liver injury, characterized by a marked increase in steatosis and liver damage with 10 days of a liquid diet containing 5% ethanol followed by a single ethanol binge (5 g/kg). Therefore, we employed this model to explore the status of surfactant phospholipids, oxidative stress, tissue injury markers and inflammatory cytokines in lungs. In lungs of C57BL/6J mice, the alcohol feeding significantly increased levels of the surfactant phospholipid dipalmitoyl phosphatidylcholine (DPPC) as well as the truncated oxidized phosphatidylcholines palmitoyl oxovaleryl phosphatidyl-choline (POVPC), palmitoyl glutaryl phosphatidyl-choline (PGPC), palmitoyl oxo-nonanoyl phosphatidyl-choline (ALDO-PC), and palmitoyl azelaoyl phosphatidyl-choline (PAzePC) at 9 h post-binge. Additionally, gene expression of the enzymes catalyzing lipid oxidation, such as arachidonate 15-lipoxygenase (Alox15), prostaglandin synthase 2 (Ptgs2), Cytochrome P450 2E1 (Cyp2E1) and NADPH oxidase 1 (Nox1) were significantly increased. Furthermore, ethanol increased levels of the inflammatory cytokine Interleukin-17 in bronchoalveolar lavage fluid. In conclusion, the NIAAA alcohol feeding model might be suitable to study alcohol-induced lung injury and inflammation.

Effects of intestine-specific deletion of fibroblast growth factor 15 on alcoholic liver disease development in mice

Background and aimsAlcoholic liver disease (ALD) is an important and growing cause for the development of chronic liver diseases in the world. Bile acid (BA) levels are increased in patients with ALD and dysregulation of BA homeostasis worsens ALD. BA synthesis is critically regulated by fibroblast growth factor (FGF)15 in mice and FGF19 in humans. FGF15/19 are mainly produced in the ileum and their main function is to suppress BA synthesis in the liver through the activation of fibroblast growth factor receptor 4 (FGFR4) on hepatocytes. The effects of intestine-specific Fgf15 deficiency on the development of ALD were determined in the current study. MethodsEnterocyte-specific Fgf15 knockout mice (Fgf15int−/−) and the established mouse model by chronic and binge ethanol feeding (NIAAA model) were adapted in this study. ResultsThe Fgf15int−/− mice had increased BA pool size, consistent with negative effects of FGF15-FGFR4 signaling on BA synthesis. There were not obviously physical and hepatic histological abnormalities presented in Fgf15int−/− mice compared to wild-type mice. Following alcohol treatment, the Fgf15int−/− mice exhibited a higher degree of liver injury, increased hepatic expression of Cd14, a receptor for lipopolysaccharide expressed in the liver, and increased hepatic lipid levels. We did not observe alterations in the levels of fibrosis in the liver or expression of genes involved in hepatic fibrosis, regardless of genotypes or following the alcohol treatment. ConclusionsFGF15 may prevent hepatic steatosis in the development of ALD in mice, and maintaining FGF19/FGFR4 signaling may be critical in the prevention and/or treatment of ALD in humans in the future.

Hepatic NCoR1 deletion exacerbates alcohol-induced liver injury in mice by promoting CCL2-mediated monocyte-derived macrophage infiltration.

Nuclear receptor corepressor 1 (NCoR1) is a corepressor of the epigenetic regulation of gene transcription that has important functions in metabolism and inflammation, but little is known about its role in alcohol-associated liver disease (ALD). In this study, we developed mice with hepatocyte-specific NCoR1 knockout (NCoR1Hep-/-) using the albumin-Cre/LoxP system and investigated the role of NCoR1 in the pathogenesis of ALD and the underlying mechanisms. The traditional alcohol feeding model and NIAAA model of ALD were both established in wild-type and NCoR1Hep-/- mice. We showed that after ALD was established, NCoR1Hep-/- mice had worse liver injury but less steatosis than wild-type mice. We demonstrated that hepatocyte-specific loss of NCoR1 attenuated liver steatosis by promoting fatty acid oxidation by upregulating BMAL1 (a circadian clock component that has been reported to promote peroxisome proliferator activated receptor alpha (PPARα)-mediated fatty β-oxidation by upregulating de novo lipid synthesis). On the other hand, hepatocyte-specific loss of NCoR1 exacerbated alcohol-induced liver inflammation and oxidative stress by recruiting monocyte-derived macrophages via C-C motif chemokine ligand 2 (CCL2). In the mouse hepatocyte line AML12, NCoR1 knockdown significantly increased ethanol-induced CCL2 release. These results suggest that hepatocyte NCoR1 plays distinct roles in controlling liver inflammation and steatosis, which provides new insights into the development of treatments for steatohepatitis induced by chronic alcohol consumption.

Raphani Semen (Raphanus sativus L.) Ameliorates Alcoholic Fatty Liver Disease by Regulating De Novo Lipogenesis.

In this study, we investigated the pharmacological effect of a water extract of Raphani Semen (RSWE) on alcoholic fatty liver disease (AFLD) using ethanol-induced AFLD mice (the NIAAA model) and palmitic acid (PA)-induced steatosis HepG2 cells. An RSWE supplement improved serum and hepatic triglyceride (TG) levels of AFLD mice, as well as their liver histological structure. To explore the molecular action of RSWE in the improvement of AFLD, we investigated the effect of RSWE on four major pathways for lipid homeostasis in the liver: free fatty acid transport, lipogenesis, lipolysis, and β-oxidation. Importantly, RSWE decreased the mRNA expression of de novo lipogenesis-related genes, such as Srebf1, Cebpa, Pparg, and Lpin1, as well as the protein levels of these factors, in the liver of AFLD mice. That these actions of RSWE affect lipogenesis was confirmed using PA-induced steatosis HepG2 cells. Overall, our findings suggest that RSWE has the potential for improvement of AFLD by inhibiting de novo lipogenesis.

Camel milk ameliorates inflammatory mechanisms in an alcohol-induced liver injury mouse model

Camel milk (CM) is considered to protect the liver in the practice of traditional medicine in nomadic areas. The purpose of the present study was to investigate the effects of CM on the hepatic biochemical and multiple omics alterations induced by chronic alcoholic liver disease (ALD). An intragastric gavage mice Lieber DeCarli + Gao binge model (NIAAA model) was employed to investigate the inflammatory mechanism of camel milk on the liver tissue of mice. A gut microbiota of the feces of mice and transcriptomic and proteomic analyses of the liver of mice were performed. Analysis of serum and liver biochemical indexes revealed that camel milk not only prevents alcohol-induced colonic dysfunction and lipid accumulation, but also regulates oxidative stress and inflammatory cytokine production to protect against chronic ALD in mouse. The gut microbial community of mice treated with camel milk was more similar to the untreated control group than to the model group, indicating that the intake of camel milk pre- and post-alcohol gavage effectively prevents and alleviates the intestinal microbial disorder caused by chronic alcoholism in mice. Furthermore, the results of the transcriptomic and proteomic analyses of the liver tissue showed that camel milk can improve alcoholic liver injury in mice by regulating inflammatory factors and immune system disruptions. This study provides insights into the molecular mechanism by which camel milk can be developed as a potential functional food with no side effects and against liver injury.

Alcohol stimulates the proliferation of mouse small intestinal epithelial cells via Wnt signaling

The intestinal epithelium is one of the fastest renewing tissues in mammals and is a barrier against toxic substances such as alcohol. Excessive alcohol can induce intestinal damage leading to intestinal bowel diseases. Thus, the control of small intestinal epithelial cell (IEC) regeneration is thought to be important for homeostasis in response to epithelium damage. However, reports on how epithelial cells respond to small intestinal damage are scarce. We investigated the effects of alcohol consumption on small intestinal epithelial cells of mice. To verify that alcohol altered the small intestinal epithelium, we used 8–10 weeks old male C57BL/6J mice for models of chronic and binge alcohol consumption (the NIAAA model) in addition to an organoid model. Alcohol promoted the proliferative activity of IECs and intestinal stem cells (ISCs) in intestinal crypts. Alcohol consumption increased expression of the proliferation marker cyclin D1 and activated the p44/42 MAPK (Erk1/2) signaling pathway in small intestinal epithelial cells. The Wnt target genes were markedly increased in IECs from alcohol-treated mice. In the small intestinal organoid model exposed to alcohol, the organoid area and numbers of buds increased with alcohol concentrations up to 0.5% similar to in vivo observations. These results suggest that alcohol consumption stimulates the proliferation of small intestinal epithelial cells via Wnt signaling.

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.

Deficiency of Intestinal α1-2-Fucosylation Exacerbates Ethanol-Induced Liver Disease in Mice.

Fucosyltransferase 2 (Fut2)-mediated intestinal α1-2-fucosylation is important in maintaining a symbiotic host-microbiota relationship and can protect against several pathogens. Intestinal dysbiosis is an important factor for the progression of experimental ethanol (EtOH)-induced liver disease, but the role of Fut2 in modulating the intestinal glycocalyx during alcohol-associated liver disease is unknown. We investigated the role of Fut2-mediated intestinal α1-2-fucosylation for the development of alcohol-associated liver disease. Immunohistochemistry staining was applied to evaluate α1-2-fucosylation in duodenal biopsies from patients with alcohol use disorder. Wild-type (WT) and Fut2-deficient littermate mice were subjected to Lieber-DeCarli models of chronic EtOH administration and the chronic-binge EtOH diet (NIAAA model). Intestinal α1-2-fucosylation was down-regulated in patients with alcohol use disorder. Lack of α1-2-fucosylation in Fut2-deficient mice exacerbates chronic EtOH-induced liver injury, steatosis, and inflammation without affecting EtOH metabolism. Dietary supplementation of the α1-2-fucosylated glycan 2'-fucosyllactose (2'-FL) ameliorates EtOH-induced liver disease in Fut2-deficient mice in the NIAAA model. Despite no direct effects on growth of Enterococcus faecalis in vitro, intestinal α1-2-fucosylation reduces colonization of cytolysin-positive E. faecalis in the intestine of EtOH-fed mice. Intestinal α1-2-fucosylation acts as a host-protective mechanism against EtOH-induced liver disease. 2'-FL is an oligosaccharide naturally present in human milk that could be considered as therapeutic agent for alcohol-associated liver disease.

Alox12/15 Deficiency Exacerbates, While Lipoxin A4 Ameliorates Hepatic Inflammation in Murine Alcoholic Hepatitis.

Alcoholism is one of the leading and increasingly prevalent reasons of liver associated morbidity and mortality worldwide. Alcoholic hepatitis (AH) constitutes a severe disease with currently no satisfying treatment options. Lipoxin A4 (LXA4), a 15-lipoxygenase (ALOX15)-dependent lipid mediator involved in resolution of inflammation, showed promising pre-clinical results in the therapy of several inflammatory diseases. Since inflammation is a main driver of disease progression in alcoholic hepatitis, we investigated the impact of endogenous ALOX15-dependent lipid mediators and exogenously applied LXA4 on AH development. A mouse model for alcoholic steatohepatitis (NIAAA model) was tested in Alox12/15+/+ and Alox12/15−/− mice, with or without supplementation of LXA4. Absence of Alox12/15 aggravated parameters of liver disease, increased hepatic immune cell infiltration in AH, and elevated systemic neutrophils as a marker for systemic inflammation. Interestingly, i.p. injections of LXA4 significantly lowered transaminase levels only in Alox12/15−/− mice and reduced hepatic immune cell infiltration as well as systemic inflammatory cytokine expression in both genotypes, even though steatosis progressed. Thus, while LXA4 injection attenuated selected parameters of disease progression in Alox12/15−/− mice, its beneficial impact on immunity was also apparent in Alox12/15+/+ mice. In conclusion, pro-resolving lipid mediators may be beneficial to reduce inflammation in alcoholic hepatitis.