Microbiome as a therapeutic target in alcohol-related liver disease

Application progress of early nutrition intervention in patients with hepatocellular carcinoma after liver transplantation

Liver transplantation, as an effective therapy for patients with liver cancer, plays an important role in improving the quality of life of patients. However, the complexity and trauma of liver transplantation can easily lead to the occurrence of malnutrition in patients, and then increase the risk of postoperative complications, which has aroused widespread clinical attention. Reasonable nutritional support can not only maintain the stability of the body’s internal environment, reduce the occurrence of complications, but also promote the recovery of liver and other organ functions. In recent years, with the in-depth understanding of nutritional metabolism after liver transplantation, the application of enteral nutrition and parenteral nutrition in nutritional support after liver transplantation has been increasingly extensive and achieved remarkable results. This paper discusses the effect of early postoperative nutritional intervention on patients with liver cancer and liver transplantation, and combined with its mechanism of action, can better understand the effectiveness of intervention, and provide reference for the development of scientific and reasonable nutritional support programs in clinical practice.

Aryl hydrocarbon receptor (AHR) and nuclear factor erythroid-derived 2-like 2 (NRF2): An important crosstalk in the gut-liver axis

The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor, mainly involved in detoxification. However, in the intestine, metabolites derived from the diet, which are converted by a wide range of bacteria can also activate the AHR. This intestinal AHR activation plays a key role in maintaining the gut barrier by, for example, upregulating antimicrobial peptides and anti-inflammatory cytokines. Since the gut barrier influences the gut-liver axis by regulating the leaking of metabolites, bacteria, and endotoxins into circulation and particularly into the liver, the AHR is a key factor in the gut-liver axis. Vice versa, certain liver pathologies also influence the gut microbiome, thereby altering bacteria-derived activation of the AHR. Additionally, bile acids can impact the gut via the liver and thereby also affect the AHR. The aryl hydrocarbon receptor (AHR) interacts with several molecular factors, one of which is the nuclear factor erythroid-derived 2-like 2 (NRF2), a transcription factor primarily associated with regulating antioxidant stress responses. The interplay between AHR and NRF2 has been investigated in the context of various diseases; this review highlights the significance of this interaction within the framework of the gut-liver axis.

Liver diseases: epidemiology, causes, trends and predictions

As a highly complex organ with digestive, endocrine, and immune-regulatory functions, the liver is pivotal in maintaining physiological homeostasis through its roles in metabolism, detoxification, and immune response. Various factors including viruses, alcohol, metabolites, toxins, and other pathogenic agents can compromise liver function, leading to acute or chronic injury that may progress to end-stage liver diseases. While sharing common features, liver diseases exhibit distinct pathophysiological, clinical, and therapeutic profiles. Currently, liver diseases contribute to approximately 2 million deaths globally each year, imposing significant economic and social burdens worldwide. However, there is no cure for many kinds of liver diseases, partly due to a lack of thorough understanding of the development of these liver diseases. Therefore, this review provides a comprehensive examination of the epidemiology and characteristics of liver diseases, covering a spectrum from acute and chronic conditions to end-stage manifestations. We also highlight the multifaceted mechanisms underlying the initiation and progression of liver diseases, spanning molecular and cellular levels to organ networks. Additionally, this review offers updates on innovative diagnostic techniques, current treatments, and potential therapeutic targets presently under clinical evaluation. Recent advances in understanding the pathogenesis of liver diseases hold critical implications and translational value for the development of novel therapeutic strategies.

Regulatory mechanisms of the probiotic-targeted gut-liver axis for the alleviation of alcohol-related liver disease: a review

Alcohol abuse-triggered alcohol-related liver disease (ALD) has become as a global public health concern that substantially affects the well-being and clinical status of patients. Although modern medicine provides various treatments for ALD, their effectiveness is limited and can lead to adverse side effects. Probiotics have been employed to prevent, alleviate, and even treat ALD, with promising results. However, few comprehensive reviews are available on how they mitigate ALD by targeting the gut-liver axis. This review systematically clarifies the specific mediators of the gut-liver axis in healthy states. It also describes the alterations observed in ALD. Furthermore, this review thoroughly summarizes the underlying mechanisms through which probiotics act on the gut-liver axis to relieve ALD. It also discusses the current status and challenges faced in clinical research applications. Finally, we discuss the challenges and future prospects of using probiotics to treat ALD. This review improves our understanding of ALD and supports the development and application of probiotics that target the gut-liver axis for therapeutic use.

Ginsenoside Rg1: A bioactive therapeutic agent for diverse liver diseases

Diverse liver diseases are characterised by late diagnosis and rapid progression and have become one of the major threats to human health. To delay the transition from benign tissue lesions to a substantial organ injury, scientists have gradually applied natural compounds derived from plants as a complementary therapy in the field of hepatology. Ginseng (Panax ginseng C. A. Meyer) is a tonic traditional Chinese herbal medicine, and natural products, including ginsenoside Rg1 (G-Rg1), which is a kind of 20(S)-protopanaxatriol saponin with a relatively high biological activity, can be isolated from the roots or stems of ginseng. Given these information, this review aimed to summarise and discuss the metabolic mechanisms of G-Rg1 in the regulation of diverse liver diseases and the measures to improve its bioavailability. As a kind of monomer in Chinese medicine with multitarget pharmacological effects, G-Rg1 can provide significant therapeutic benefits in the alleviation of alcoholic liver disease, nonalcoholic fatty liver disease, liver fibrosis, viral hepatitis, etc., which mainly rely on the inhibition of apoptosis, strengthening endogenous anti-inflammatory and antioxidant mechanisms, activation of immune responses and regulation of efflux transport signals, to improve pathological changes in the liver caused by lipid deposition, inflammation, oxidative stress, accumulation of hepatotoxic product, etc. However, the poor bioavailability of G-Rg1 must be overcome to improve its clinical application value. In summary, focusing on the hepatoprotective benefits of G-Rg1 will provide new insights into the development of natural Chinese medicine resources and their pharmaceutical products to target the treatment of liver diseases.

Bacteria/Nanozyme Composites: New Therapeutics for Disease Treatment

Bacterial therapy is recognized as a cost-effective treatment for several diseases. However, its development is hindered by limited functionality, weak inherent therapeutic effects, and vulnerability to harsh microenvironmental conditions, leading to suboptimal treatment activity. Enhancing bacterial activity and therapeutic outcomes emerges as a pivotal challenge. Nanozymes have garnered significant attention due to their enzyme-mimic activities and high stability. They enable bacteria to mimic the functions of gene-edited bacteria expressing the same functional enzymes, thereby improving bacterial activity and therapeutic efficacy. This review delineates the therapeutic mechanisms of bacteria and nanozymes, followed by a summary of strategies for preparing bacteria/nanozyme composites. Additionally, the synergistic effects of such composites in biomedical applications such as gastrointestinal diseases and tumors are highlighted. Finally, the challenges of bacteria/nanozyme composites are discussed and propose potential solutions. This study aims to provide valuable insights to offer theoretical guidance for the advancement of nanomaterial-assisted bacterial therapy.

Gut Microbiota as Emerging Players in the Development of Alcohol-Related Liver Disease

The global incidence and mortality rates of alcohol-related liver disease are on the rise, reflecting a growing health concern worldwide. Alcohol-related liver disease develops due to a complex interplay of multiple reasons, including oxidative stress generated during the metabolism of ethanol, immune response activated by immunogenic substances, and subsequent inflammatory processes. Recent research highlights the gut microbiota's significant role in the progression of alcohol-related liver disease. In patients with alcohol-related liver disease, the relative abundance of pathogenic bacteria, including Enterococcus faecalis, increases and is positively correlated with the level of severity exhibited by alcohol-related liver disease. Supplement probiotics like Lactobacillus, as well as Bifidobacterium, have been found to alleviate alcohol-related liver disease. The gut microbiota is speculated to trigger specific signaling pathways, influence metabolite profiles, and modulate immune responses in the gut and liver. This research aimed to investigate the role of gut microorganisms in the onset and advancement of alcohol-related liver disease, as well as to uncover the underlying mechanisms by which the gut microbiota may contribute to its development. This review outlines current treatments for reversing gut dysbiosis, including probiotics, fecal microbiota transplantation, and targeted phage therapy. Particularly, targeted therapy will be a vital aspect of future alcohol-related liver disease treatment. It is to be hoped that this article will prove beneficial for the treatment of alcohol-related liver disease.

Alcoholic Extracts from the Ganoderma Lucidum Fermentation Product Alleviated Ethanol-Induced Liver Injury, Gut Leakiness, and Gut Dysbiosis in Mice

The hepatoprotective effect of the alcoholic extracts of Ganoderma lucidum fermentation products (GFE) was investigated. C57BL/6 mice were pretreated with GFE for 7 days and then subjected to the chronic-binge ethanol feeding model. GFE pretreatment significantly reduced the ethanol-induced elevated serum levels of aspartate aminotransferase (AST) and alanine transaminase (ALT), hepatic steatosis, and increased triglyceride content. GFE pretreatment also altered hepatic alcohol metabolism, suppressed oxidative stress by decreasing the expression of Cyp2e1, and increasing the level of GSH. Lipidmoic analysis revealed that GFE pretreatment effectively increased ratio of phosphatidylcholines /phosphatidylethanolamine (PC/PE) in the liver. Furthermore, mice pretreated with GFE demonstrated decreased hepatic inflammation and plasma lipopolysaccharide (LPS) levels. Additionally, the mRNA expression of gut tight junction proteins such as ZO-1, Occludin and Claudin-1, along with antimicrobial peptide (e.g., Reg3β and Reg3γ) were up-regulated by GFE pretreatment. 16s rRNA sequencing revealed that GFE increased Bacteroidales, Parabacteroides, and Dubosiella, which were associated with hepatic steatosis, inflammation and intestinal barrier function parameters. These results demonstrate that GFE can prevent ethanol-induced liver injury and inflammation, gut leakiness and restore gut microbiota dysbiosis.

Distinct alterations of gut microbiota between viral- and non-viral-related hepatocellular carcinoma

Altered gut microbiota has been connected to hepatocellular carcinoma (HCC) occurrence and advancement. This study was conducted to identify a gut microbiota signature in differentiating between viral-related HCC (Viral-HCC) and non-hepatitis B-, non-hepatitis C-related HCC (NBNC-HCC). Fecal specimens were obtained from 16 healthy controls, 33 patients with viral-HCC (17 and 16 cases with hepatitis B virus (HBV) and hepatitis C virus (HCV) infection, respectively), and 18 patients with NBNC-HCC. Compositions of fecal microbiota were assessed by 16S rRNA sequencing. Bioinformatic analysis was performed by the DADA2 pipeline in the R program. Significantly different genera from the top 50 relative abundance were used to classify between subgroups of HCC by the Random Forest algorithm. Our data demonstrated that the HCC group had a significantly decreased alpha-diversity and changed microbial composition in comparison with healthy controls. Within the top 50 relative abundance, there were 11 genera including Faecalibacterium, Agathobacter, and Coprococcus that were significantly enhanced in Viral-HCC, while 5 genera such as Bacteroides, Streptococcus, Ruminococcus gnavus group, Parabacteroides, and Erysipelatoclostridium were enhanced in NBNC-HCC. Compared to Viral-HCC, the NBNC-HCC subgroup significantly reduced various short-chain fatty acid-producing bacteria, as well as declined fecal butyrate but elevated plasma surrogate markers of microbial translocation. Based on the machine learning algorithm, a high diagnostic accuracy to classify HCC subgroups was achieved with an area under the receiver-operating characteristic (ROC) curve (AUC) of 0.94. Collectively, these data revealed that gut dysbiosis was distinct according to etiological factors of HCC, which might play an essential role in hepatocarcinogenesis. These findings underscore the possible use of a gut microbiota signature for the diagnosis and therapeutic approaches regarding different subgroups of HCC. KEY POINTS: • Gut dysbiosis is connected to hepatocarcinogenesis and can be used as a novel biomarker. • Gut microbiota composition is significantly altered in different etiological factors of HCC. • Microbiota-based signature can accurately distinguish between Viral-HCC and NBNC-HCC.

Hepatoprotective potential of four fruit extracts rich in different structural flavonoids against alcohol-induced liver injury via gut microbiota-liver axis

Alcoholic liver injury (ALI) accounts for a major share of the global burden of non-viral liver disease. In the absence of specialized medications, research on using fruit flavonoids as a treatment is gaining momentum. This study investigated the hepatoprotective effects of four fruits rich in structurally diverse flavonoids: ougan (Citrus reticulata cv. Suavissima, OG), mulberry (Morus alba L., MB), apple (Malus × domestica Borkh., AP), and turnjujube (Hovenia dulcis Thunnb., TJ). A total of one flavanone glycoside, three polymethoxyflavones, two anthocyanins, one flavonol glycoside, and one dihydroflavonol were identified through UPLC analysis. In an acute ethanol-induced ALI mouse model, C57BL/6J mice were supplemented with 200 mg/kg·BW/day of different fruit extracts for three weeks. Our results showed that the four extracts exhibited promising benefits in improving lipid metabolism disorders, iron overload, and oxidative stress. RT-PCR and Western blot tests suggested that the potential mechanism may partially be attributed to the activation of the NRF2-mediated antioxidant response and the inhibition of ferroptosis pathways. Furthermore, fruit extracts administration demonstrated a specific regulatory role in intestinal microecology, with increases in beneficial bacteria such as Dubosiella, Lactobacillus, and Bifidobacterium. Spearman correlation analysis revealed strong links between intestinal flora, lipid metabolism, and iron homeostasis, implying that the fruit extracts mitigated ALI via the gut microbiota-liver axis. In vitro experiments reaffirmed the activity against ethanol-induced oxidative damage and highlighted the positive effects of flavonoid components. These findings endorse the prospective application of OG, MB, AP, and TJ as dietary supplements or novel treatments for ALI.

The pyruvate dehydrogenase kinase inhibitor dichloroacetate mitigates alcohol-induced hepatic inflammation and metabolic disturbances in mice

BACKGROUND

Dichloroacetate (DCA), a pan-pyruvate dehydrogenase kinase inhibitor, ameliorates multiple pathological conditions and tissue injury and shows strong potential for clinical applications. Here, we investigated the preventive effects of DCA in a murine model of alcohol-associated liver disease.

METHODS

C57BL/6J mice were subjected to the acute-on-chronic model of alcohol-associated liver disease and treated with DCA. Livers were assessed in liver histology, biochemistry, and gene expression. Mass spectrometry was used to compare protein expression and metabolite levels.

RESULTS

DCA inhibited hepatic expression of inflammatory genes but did not prevent steatosis and hepatocellular injury in ethanol-fed mice. Consistently, DCA repressed the expression of mRNAs for inflammatory genes in LPS-stimulated murine bone-marrow-derived macrophages and human monocytic THP-1 cells and inhibited both gene expression and protein release of interleukin-1 beta. DCA prevented hepatic accumulation of isovaleric acid in ethanol-fed mice, a short-chain fatty acid primarily produced by gut microbiota. In vitro, isovaleric acid potentiated LPS's effects, while DCA prevented this proinflammatory action. Ethanol feeding increased the expression of proteins involved in diverse metabolic pathways, including branched-chain amino acid (BCAA) degradation. In ethanol-fed mice, hepatic Fischer's ratio (the molar ratio of BCAAs to aromatic amino acids Phe and Tyr) and BTR (the molar ratio of BCAAs to Tyr) showed a decrease compared to pair-fed mice; however, this decrease was not observed in DCA-treated ethanol-fed mice. DCA blunted the ethanol-induced increase of BCKDHA, the rate-limiting enzyme in BCAA catabolism, and cytochrome P450 2E1.

CONCLUSIONS

Ethanol-induced hepatic inflammatory responses and metabolic disturbances were prevented by DCA in mice, indicating the potential to develop pyruvate dehydrogenase kinase inhibitors as an effective therapy to treat alcohol-associated liver disease.

3PM-guided innovation in treatments of severe alcohol-associated hepatitis utilizing fecal microbiota transplantation

Rationale

Severe alcohol-associated hepatitis (SAH) is the most critical, acute, inflammatory phenotype within the alcohol-associated liver disease (ALD) spectrum, characterized by high 30- and 90-day mortality. Since several decades, corticosteroids (CS) are the only approved pharmacotherapy offering highly limited survival benefits. Contextually, there is an evident demand for 3PM innovation in the area meeting patients' needs and improving individual outcomes. Fecal microbiota transplantation (FMT) has emerged as one of the new potential therapeutic options. In this study, we aimed to address the crucial 3PM domains in order to assess (i) the impact of FMT on mortality in SAH patients beyond CS, (ii) to identify factors associated with the outcome to be improved (iii) the prediction of futility, (iv) prevention of suboptimal individual outcomes linked to increased mortality, and (v) personalized allocation of therapy.

Methods

We conducted a prospective study (NCT04758806) in adult patients with SAH who were non-responders (NR) to or non-eligible (NE) for CS between January 2018 and August 2022. The intervention consisted of five 100 ml of FMT, prepared from 30 g stool from an unrelated healthy donor and frozen at - 80 °C, administered daily to the upper gastrointestinal (GI) tract. We evaluated the impact of FMT on 30- and 90-day mortality which we compared to the control group selected by the propensity score matching and treated by the standard of care; the control group was derived from the RH7 registry of patients hospitalized at the liver unit (NCT04767945). We have also scrutinized the FMT outcome against established and potential prognostic factors for SAH - such as the model for end-stage liver disease (MELD), Maddrey Discriminant Function (MDF), acute-on-chronic liver failure (ACLF), Liver Frailty Index (LFI), hepatic venous-portal pressure gradient (HVPG) and Alcoholic Hepatitis Histologic Score (AHHS) - to see if the 3PM method assigns them a new dimension in predicting response to therapy, prevention of suboptimal individual outcomes, and personalized patient management.

Results

We enrolled 44 patients with SAH (NR or NE) on an intention-to-treat basis; we analyzed 33 patients per protocol for associated factors (after an additional 11 being excluded for receiving less than 5 doses of FMT), and 31 patients by propensity score matching for corresponding individual outcomes, respectively. The mean age was 49.6 years, 11 patients (33.3%) were females. The median MELD score was 29, and ACLF of any degree had 27 patients (81.8%). FMT improved 30-day mortality (p = 0.0204) and non-significantly improved 90-day mortality (p = 0.4386). Univariate analysis identified MELD ≥ 30, MDF ≥ 90, and ACLF grade > 1 as significant predictors of 30-day mortality, (p = 0.031; p = 0.014; p = 0.034). Survival was not associated with baseline LFI, HVPG, or AHHS.

Conclusions and recommendations in the framework of 3PM

In the most difficult-to-treat sub-cohort of patients with SAH (i.e., NR/NE), FMT improved 30-day mortality. Factors associated with benefit included MELD ≤ 30, MDF ≤ 90, and ACLF < 2. These results support the potential of gut microbiome as a therapeutic target in the context of 3PM research and vice versa - to use 3PM methodology as the expedient unifying template for microbiome research. The results allow for immediate impact on the innovative concepts of (i) personalized phenotyping and stratification of the disease for the clinical research and practice, (ii) multilevel predictive diagnosis related to personalized/precise treatment allocation including evidence-based (ii) prevention of futile and sub-optimally effective therapy, as well as (iii) targeted prevention of poor individual outcomes in patients with SAH. Moreover, our results add to the existing evidence with the potential to generate new research along the SAH's pathogenetic pathways such as diverse individual susceptibility to alcohol toxicity, host-specific mitochondrial function and systemic inflammation, and the role of gut dysbiosis thereof.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-024-00381-5.

Risk factors and prognostic impact of new decompensated events in hospitalized patients with decompensated cirrhosis

BACKGROUND

Decompensated cirrhosis (DC) is prone to recurrent episodes of decompensation following the initial event. This study aimed to identify the risk factors for subsequent decompensation and assess their impact on the outcomes of patients hospitalized for DC.

METHODS

Patients with DC were divided into two groups based on the occurrence of new decompensated events during hospitalization. Logistic regression analysis was employed to identify risk factors for new decompensation. The Cox proportional hazards model was used to evaluate the relationship between new decompensation and short-term mortality risk in these patients.

RESULTS

The study cohort consisted of 339 patients with DC, with a median age of 57 years. During hospitalization, 83 patients (24.5%) experienced new decompensated events, with bacterial infections (BIs) being the most common (n = 46, 13.6%). Multivariate analysis revealed that the Model for End-Stage Liver Disease (MELD) score at admission (OR = 1.06, 95% CI: 1.02-1.11, P = 0.005) was the sole risk factor for new decompensation during hospitalization. Patients who experienced new decompensation had significantly higher 28-day (28.9% vs. 7.0%, P < 0.001) and 90-day (33.7% vs. 15.2%, P < 0.001) transplant-free mortality compared to those who did not. After adjusting for white cell count, C-reactive protein, and MELD score, new decompensation during hospitalization was identified as an independent risk factor for 28-day and 90-day mortality (HR = 2.63, 95% CI: 1.42-4.87, P = 0.002 and HR = 1.73, 95% CI: 1.04-2.88, P = 0.033, respectively).

CONCLUSIONS

Patients with high MELD scores are susceptible to new decompensation during hospitalization, and the occurrence of new decompensation adversely affects short-term mortality in patients with DC.

Ellagic Acid Protects against Alcohol-Related Liver Disease by Modulating the Hepatic Circadian Rhythm Signaling through the Gut Microbiota-NPAS2 Axis

Alcohol-related liver disease (ALD) encompasses a spectrum of hepatic disorders resulting from alcohol abuse, which constitutes the predominant etiology of morbidity and mortality associated with hepatic pathologies globally. Excessive alcohol consumption disrupts the integrity of the intestinal barrier and perturbs the balance of gut microbiota, thereby facilitating the progression of ALD. Ellagic acid (EA) has been extensively reported to be an effective intervention for alleviating liver symptoms. However, the target molecules of EA in improving ALD and its underlying mechanism remain elusive. First, our study indicates that EA ameliorated ALD through the hepatic circadian rhythm signaling by up-regulating neuronal PAS domain protein 2 (NPAS2). Furthermore, analysis of the intestinal microbiome showed that EA significantly enhanced the abundance of beneficial bacteria, which was positively correlated with NPAS2 expression and negatively correlated with liver injury. Finally, antibiotic treatment and fecal microbiota transplantation (FMT) experiments established a causal relationship between the reshaped microbiota and NPAS2 in the amelioration of ALD. In summary, our study demonstrates novel evidence that EA attenuated ALD by modulating the hepatic circadian rhythm signaling pathway via the gut microbiota-NPAS2 axis, providing valuable insights for EA and microbiome-targeted interventions against ALD.

Convergence of Alcohol Consumption and Dietary Quality in US Adults Who Currently Drink Alcohol: An Analysis of Two Core Risk Factors of Liver Disease

BACKGROUND/OBJECTIVES

Alcohol consumption and poor dietary habits are on the rise in the United States, posing significant challenges to public health due to their contribution to chronic diseases such as liver failure. While associations between alcohol consumption patterns and diet quality have been explored, the relationship between specific alcoholic beverage types and diet quality remains underexamined. This study aims to compare diet quality among consumers of different alcoholic beverage types.

METHODS

We conducted a cross-sectional analysis of 1917 current alcohol drinkers from the National Health and Nutrition Examination Survey (NHANES) who completed a 24 h dietary recall survey. Diet quality was assessed using the Healthy Eating Index (HEI), with higher scores indicating superior diet quality. Multivariable logistic regression models were employed to assess differences in HEI between consumers of various alcoholic beverage types, using wine-only drinkers as the reference group and controlling for demographic, socioeconomic, lifestyle, and metabolic syndrome variables.

RESULTS

Beer-only drinkers were more likely to have lower income, higher rates of cigarette smoking, and insufficient physical activity compared to other alcohol consumers. In the fully adjusted multivariable model, beer-only drinkers had an HEI score that was 3.12 points lower than wine-only drinkers. In contrast, liquor/cocktail-only and multiple-type drinkers had similar HEI scores to wine-only drinkers.

CONCLUSIONS

Beer-only consumption is associated with poorer diet quality among alcohol drinkers. Targeted patient education and public health campaigns may be effective in addressing the combined impact of alcohol consumption and poor diet quality on chronic disease risk.

Rice Protein Peptides Alleviate Alcoholic Liver Disease via the PPARγ Signaling Pathway: Through Liver Metabolomics and Gut Microbiota Analysis

Alcoholic liver disease (ALD) is the predominant type of liver disease worldwide, resulting in significant mortality and a high disease burden. ALD damages multiple organs, including the liver, gut, and brain, causing inflammation, oxidative stress, and fat deposition. In this study, we investigated the effects of rice protein peptides (RPP) on ALD in mice with a primary focus on the gut microbiota and liver metabolites. The results showed that administration of RPP significantly alleviated the symptoms of ALD in mice including adiposity, oxidative stress, and inflammation. The KEGG pathway shows that RPP downregulates the liver metabolite of capric acid and the metabolism of fatty acid biosynthesis compared with the MOD group. Mechanistically, RPP downregulated the PPARγ signaling pathway and suppressed the expression of fatty acid biosynthesis genes (FASN, ACC1, ACSL1, and ACSL3). Furthermore, two active peptides (YLPTKQ and PKLPR) with potential therapeutic functions for ALD were screened by Caco-2 cell modeling and molecular docking techniques. In addition, RPP treatment alleviates gut microbiota dysbiosis by reversing the F/B ratio, increasing the relative abundance of Alloprevotella and Alistipes, and upregulating the level of short-chain fatty acids. In conclusion, RPP alleviates ALD steatosis through the PPARγ signaling pathway by YLPTKQ and PKLPR and regulates gut microbiota.

Galangin Alleviates Alcohol-Provoked Liver Injury Associated with Gut Microbiota Disorder and Intestinal Barrier Dysfunction in Mice

Prolonged and excessive intake of alcohol results in the onset of alcoholic liver disease, which is marked by oxidative stress, intestinal barrier dysfunction, and disturbance in the intestinal microbiome. Galangin, a potent flavonoid from Alpinia officinarum Hance, has been recognized for its diverse biological properties; however, its ability for protecting against alcohol-stimulated hepatotoxicity remains unexplored in prior research. In the current study, a Gao-Binge mouse model was established to assess the positive role and mechanisms of galangin upon alcohol-induced liver injury. The administration of galangin relieved liver pathological damage, oxidative stress, and NLRP3-mediated inflammation induced by alcohol. In addition, galangin significantly reversed abnormal intestinal histopathological manifestations and damaged the intestinal barrier function. Furthermore, microbiota composition revealed that galangin improved intestinal imbalance by improving the gut microbiota dysbiosis and short-chain fatty acid level. Collectively, this study explored the interactions between phytochemical factors and virulence factors and discovered that galangin powerfully improved alcohol-induced liver disease by repressing the inflammatory cascade via the gut microbiota-mediated gut-liver axis. These results suggested that alcohol-targeted natural products could have potential applications in promoting food safety and human health and offer valuable insights into the possible use of these substances in these important areas.

Ethanol with thioacetamide murine model of alcoholic liver disease identifies hepatic pathways as targets for the human disease

INTRODUCTION AND OBJECTIVES

Hepatic proteome and gut microbiota alterations are known in alcohol-associated hepatitis (AAH). Current animal models sparsely mimic human AAH. We aimed to develop an murine model that closely resembled human AAH.

MATERIALS AND METHODS

Male C57BL/6N mice were pair-fed control/incremental ethanol Lieber-DeCarli diets and thioacetamide (TAA) for 12-weeks to induce AAH. Hepatic proteome was analyzed using LC-MS/MS. Gut-bacteria was determined using 16s-rRNA sequencing.

RESULTS

Mice exposed to EtOH+TAA displayed higher expression of liver triglycerides (1.5-fold, p = 0.001), pro-inflammatory (IL6, 1.5-fold, p = 0.002 and TNFα, 1.7-fold, p = 0.01), fibrotic (TGF-β, 2.7-fold, p = 0.01 and Col1α1, 2-fold, p = 0.01) and oxidative markers (GSH and SOD (-1.5 fold, p = 0.004 & 0.005 respectively)) as compared to EtOH alone. Histology of EtOH+TAA liver displayed pericellular liver fibrosis, increased steatosis, and neutrophil infiltration, which resembled human AAH. In the 12wk EtOH+TAA group, Desulfobacteria, Campylobacteria, and Patescibacteria increased by 2-fold (p = 0.02). Pathway combined score (CS, log10) in EtOH+TAA treatment showed upregulated hepatic ethanol oxidation (CS=1.93), fatty acid biosynthesis (CS=2.48), necrosis (CS=1.59), collagen formation (CS=1.28) and hypoxia (CS=0.68) and downregulated fatty acid beta-oxidation (CS=2.37), PPAR signaling (CS=1.35) fatty acid degradation (CS=2.35), bile acid metabolism (CS=1.87), and oxidative phosphorylation (CS=1.50), as observed in human disease.

CONCLUSIONS

Using an ethanol-thioacetamide combination in mice results in a faster establishment of AAH with fibrosis than previously known models. Differential protein expression strongly correlates with pathways found altered in human AAH, thus making the model mimic human disease better than other known models., respectively. Thioacetamide (TAA) was administered to enhance liver fibrosis and mimic human AAH.

Fatty acid synthesis is indispensable for Kupffer cells to eliminate bacteria in ALD progression

BACKGROUND

Dysregulated fatty acid metabolism is closely linked to the development of alcohol-associated liver disease (ALD). KCs, which are resident macrophages in the liver, play a critical role in ALD pathogenesis. However, the effect of alcohol on fatty acid metabolism in KCs remains poorly understood. The current study aims to investigate fatty acid metabolism in KCs and its potential effect on ALD development.

METHODS

Wild-type C57BL/6 mice were fed a Lieber-DeCarli ethanol liquid diet for 3 days. Then, the liver injury and levels of intrahepatic bacteria were assessed. Next, we investigated the effects and underlying mechanisms of ethanol exposure on fatty acid metabolism and the phagocytosis of KCs, both in vivo and in vitro. Finally, we generated KCs-specific Fasn knockout and overexpression mice to evaluate the impact of FASN on the phagocytosis of KCs and ethanol-induced liver injury.

RESULTS

Using Bodipy493/503 to stain intracellular neutral lipids, we found significantly reduced lipid levels in KCs from mice fed an alcohol-containing diet for 3 days and in RAW264.7 macrophages exposed to ethanol. Mechanistically, alcohol exposure suppressed sterol regulatory element-binding protein 1 transcriptional activity, thereby inhibiting fatty acid synthase (FASN)-mediated de novo lipogenesis in macrophages both in vitro and in vivo. We show that genetic ablation and pharmacologic inhibition of FASN significantly impaired KC's ability to take up and eliminate bacteria. Conversely, KCs-specific Fasn overexpression reverses the impairment of macrophage phagocytosis caused by alcohol exposure. We also revealed that KCs-specific Fasn knockout augmented KCs apoptosis and exacerbated liver injury in mice fed an alcohol-containing diet for 3 days.

CONCLUSIONS

Our findings indicate the crucial role of de novo lipogenesis in maintaining effective KCs phagocytosis and suggest a therapeutic target for ALD based on fatty acid synthesis in KCs.

Inflammation, oxidative stress and gut microbiome perturbation: A narrative review of mechanisms and treatment of the alcohol hangover

Alcohol is the most widely abused substance in the world, the leading source of mortality in 15-49-year-olds, and a major risk factor for heart disease, liver disease, diabetes, and cancer. Despite this, alcohol is regularly misused in wider society. Consumers of excess alcohol often note a constellation of negative symptoms, known as the alcohol hangover. However, the alcohol hangover is not considered to have long-term clinical significance by clinicians or consumers. We undertook a critical review of the literature to demonstrate the pathophysiological mechanisms of the alcohol hangover. Hereafter, the alcohol hangover is re-defined as a manifestation of sickness behavior secondary to alcohol-induced inflammation, using the Bradford-Hill criteria to demonstrate causation above correlation. Alcohol causes inflammation through oxidative stress and endotoxemia. Alcohol metabolism is oxidative and increased intake causes relative tissue hypoxia and increased free radical generation. Tissue damage ensues through lipid peroxidation and the formation of DNA/protein adducts. Byproducts of alcohol metabolism such as acetaldehyde and congeners, sleep deprivation, and the activation of nonspecific inducible CYP2E1 in alcohol-exposed tissues exacerbate free radical generation. Tissue damage and cell death lead to inflammation, but in the intestine loss of epithelial cells leads to intestinal permeability, allowing the translocation of pathogenic bacteria to the systemic circulation (endotoxemia). This leads to a well-characterized cascade of systemic inflammation, additionally activating toll-like receptor 4 to induce sickness behavior. Considering the evidence, it is suggested that hangover frequency and severity may be predictors of the development of later alcohol-related diseases, meriting formal confirmation in prospective studies. In light of the mechanisms of alcohol-mediated inflammation, research into gut permeability and the gut microbiome may be an exciting future therapeutic avenue to prevent alcohol hangover and other alcohol-related diseases.

Systematic analysis of microorganisms' metabolism for selective targeting

Selective drugs with a relatively narrow spectrum can reduce the side effects of treatments compared to broad-spectrum antibiotics by specifically targeting the pathogens responsible for infection. Furthermore, combating an infectious pathogen, especially a drug-resistant microorganism, is more efficient by attacking multiple targets. Here, we combined synthetic lethality with selective drug targeting to identify multi-target and organism-specific potential drug candidates by systematically analyzing the genome-scale metabolic models of six different microorganisms. By considering microorganisms as targeted or conserved in groups ranging from one to six members, we designed 665 individual case studies. For each case, we identified single essential reactions as well as double, triple, and quadruple synthetic lethal reaction sets that are lethal for targeted microorganisms and neutral for conserved ones. As expected, the number of obtained solutions for each case depends on the genomic similarity between the studied microorganisms. Mapping the identified potential drug targets to their corresponding pathways highlighted the importance of key subsystems such as cell envelope biosynthesis, glycerophospholipid metabolism, membrane lipid metabolism, and the nucleotide salvage pathway. To assist in the validation and further investigation of our proposed potential drug targets, we introduced two sets of targets that can theoretically address a substantial portion of the 665 cases. We expect that the obtained solutions provide valuable insights into designing narrow-spectrum drugs that selectively cause system-wide damage only to the target microorganisms.

Solanum nigrum L. berries extract ameliorated the alcoholic liver injury by regulating gut microbiota, lipid metabolism, inflammation, and oxidative stress

Solanum nigrum L. (SN) berry is an edible berry containing abundant polyphenols and bioactive compounds, which possess antioxidant and antiinflammatory properties. However, the effects of SN on alcohol-induced biochemical changes in the enterohepatic axis remain unclear. In the current study, a chronic ethanol-fed mice ALD model was used to test the protective mechanisms of SN berries. Microbiota composition was determined via 16S rRNA sequencing, we found that SN berries extract (SNE) improved intestinal imbalance by reducing the Firmicutes to Bacteroides ratio, restoring the abundance of Akkermansia microbiota, and reducing the abundance of Allobaculum and Shigella. SNE restored the intestinal short-chain fatty acids content. In addition, liver transcriptome data analysis revealed that SNE primarily affected the genes involved in lipid metabolism and inflammatory responses. Furthermore, SNE ameliorated hepatic steatosis in alcohol-fed mice by activating AMP-activated protein kinase (AMPK), acetyl-CoA carboxylase (ACC), peroxisome proliferator-activated receptor α (PPAR-α). SNE reduced the expression of toll-like receptor 4 (TLR4), myeloid differentiation factor-88 (MyD88) nuclear factor kappa-B (NF-κB), which can indicate that SNE mainly adjusted LPS/TLR4/MyD88/NF-κB pathway to reduce liver inflammation. SNE enhanced hepatic antioxidant capacity by regulating NRF2-related protein expression. SNE alleviates alcoholic liver injury by regulating of gut microbiota, lipid metabolism, inflammation, and oxidative stress. This study may provide a reference for the development and utilization of SN resources.

Direct effects of alcohol on gut-epithelial barrier: Unraveling the disruption of physical and chemical barrier of the gut-epithelial barrier that compromises the host-microbiota interface upon alcohol exposure

The development of alcohol-associated diseases is multifactorial, mechanism of which involves metabolic alteration, dysregulated immune response, and a perturbed intestinal host-environment interface. Emerging evidence has pinpointed the critical role of the intestinal host-microbiota interaction in alcohol-induced injuries, suggesting its contribution to disease initiation and development. To maintain homeostasis in the gut, the intestinal mucosa serves as the first-line defense against exogenous factors in the gastrointestinal tract, including dietary contents and the commensal microbiota. The gut-epithelial barrier comprises a physical barrier lined with a single layer of intestinal epithelial cells and a chemical barrier with mucus trapping host regulatory factors and gut commensal bacteria. In this article, we review recent studies pertaining to the disrupted gut-epithelial barrier upon alcohol exposure and examine how alcohol and its metabolism can affect the regulatory ability of intestinal epithelium.

Alcohol and Periodontal Disease: A Narrative Review

The scientific literature dealing with alcohol and alcoholic beverages revealed that these drinks possess an adverse impact on periodontal tissues. Additionally, other principal risk factors include tobacco, smoking, poor oral hygiene, etc. It has been observed that among chronic alcoholics, there are further issues, such as mental, social, and physical effects, that promote alcoholism. These people may have weak immunity for defense against pathogenic organisms and bacteria. Thus, chances of gingival bleeding, swollen gums, bad breath, and increased bone loss are there. Different alcoholic beverages in the market cause less salivation; these beverages contain sugars that promote acid production in the oral cavity by pathogens that demineralize the enamel and damage gum and teeth. This chronic alcohol consumption can progress into different types of oral disorders, including cancer, halitosis, and caries, and is also associated with tobacco and smoking. Chronic alcohol consumption can cause alteration of the oral microbiome and increase oral pathogens, which lead to periodontal disease and an environment of inflammation created in the body due to malnutrition, diminished immunity, altered liver condition, brain damage, and gut microbiota alteration. Heavily colored alcoholic beverages produce staining on teeth and, due to less saliva, may cause other toxic effects on the periodontium. Over-dependency on alcohol leads to necrotizing lesions such as necrotizing gingivitis, necrotizing periodontitis, and necrotizing stomatitis. These pathological impairments instigate severe damage to oral structures. Therefore, proper counseling by the attending dental surgeon and related health professionals is urgently required for the patient on the basis that the individual case needs to go away from the regular heavy consumption of alcohol.

A novel dual near-infrared fluorescent probe for bioimaging and visualization of viscosity in acute alcoholic liver injury

A dual NIR fluorescent probe Cy-ND is developed for viscosity sensing with λex/em = 766/806 nm, making it apt for biological analysis, whose response is validated through DFT and TDDFT computations. Cy-ND successfully detected viscosity changes amidst acute alcohol-induced liver injury and liver ischemia-reperfusion injury.

Gut Bacteria Provide Genetic and Molecular Reporter Systems to Identify Specific Diseases

With genetic information gained from next-generation sequencing (NGS) and genome-wide association studies (GWAS), it is now possible to select for genes that encode reporter molecules that may be used to detect abnormalities such as alcohol-related liver disease (ARLD), cancer, cognitive impairment, multiple sclerosis (MS), diabesity, and ischemic stroke (IS). This, however, requires a thorough understanding of the gut-brain axis (GBA), the effect diets have on the selection of gut microbiota, conditions that influence the expression of microbial genes, and human physiology. Bacterial metabolites such as short-chain fatty acids (SCFAs) play a major role in gut homeostasis, maintain intestinal epithelial cells (IECs), and regulate the immune system, neurological, and endocrine functions. Changes in butyrate levels may serve as an early warning of colon cancer. Other cancer-reporting molecules are colibactin, a genotoxin produced by polyketide synthetase-positive Escherichia coli strains, and spermine oxidase (SMO). Increased butyrate levels are also associated with inflammation and impaired cognition. Dysbiosis may lead to increased production of oxidized low-density lipoproteins (OX-LDLs), known to restrict blood vessels and cause hypertension. Sudden changes in SCFA levels may also serve as a warning of IS. Early signs of ARLD may be detected by an increase in regenerating islet-derived 3 gamma (REG3G), which is associated with changes in the secretion of mucin-2 (Muc2). Pro-inflammatory molecules such as cytokines, interferons, and TNF may serve as early reporters of MS. Other examples of microbial enzymes and metabolites that may be used as reporters in the early detection of life-threatening diseases are reviewed.

Galangin Prevents Against Ethanol-Induced Intestinal Barrier Dysfunction and NLRP3 Inflammasome Activation via NF-κB/MAPK Signaling Pathways in Mice and Caco-2 Cells

The potential of natural phytochemicals in addressing ethanol-related public safety concerns has been garnering attention. Galangin, a potent flavonoid renowned for its antioxidative and anti-inflammatory characteristics, is derived from the galanga plant, and propolis is derived from bees. Here, we documented the effects of galangin on ethanol-stimulated intestinal tight junction damage and investigated its potential protective mechanism in both in vivo and in vitro models, which has not been extensively investigated. Our results revealed that galangin efficaciously mitigated ethanol-induced intestine injury and dysfunction of the intestinal barrier. Concurrently, galangin significantly counteracted the ethanol-induced upregulation of NLRP3 inflammasome-associated proteins and activated the mitogen-activated protein kinase (MAPK) and nuclear factor kappa-B (NF-κB) signaling pathways in both the mouse colon and Caco-2 cells. Interestingly, similar to galangin, inhibitors of MAPKs and the NF-κB p65 reduced ethanol-induced NLRP3 inflammasome activation and intestinal tight junction damage. To sum up, our results showed that galangin blocks the ethanol-induced perturbation of the intestinal barrier and activation of the NLRP3 inflammasome via the NF-κB/MAPK signaling pathways.

Palmitoleic Acid Ameliorates Metabolic Disorders and Inflammation by Modulating Gut Microbiota and Serum Metabolites

SCOPE

Palmitoleic acid (POA) is an omega-7 monounsaturated fatty acid that has been suggested to improve metabolic disorders. However, it remains unclear whether gut microbiota plays a role in the amelioration of metabolic disorders by POA. This study aims to investigate the regulation of POA on metabolism, as well as systemic inflammation in HFD-fed mice from the perspective of serum metabolome and gut microbiome.

METHODS AND RESULTS

Thirty-six C57BL/6 male mice are randomly assigned to either a normal chow diet containing 1.9% w/w lard or an HFD containing 20.68% w/w lard or 20.68% w/w sea buckthorn pulp oil for 16 weeks. The study finds that POA significantly attenuated hyperlipidemia, insulin resistance, and inflammation in HFD-fed mice. POA supplementation significantly alters the composition of serum metabolites, particularly lipid metabolites in the glycerophospholipid metabolism pathway. POA obviously increases the abundance of Bifidobacterium and decreases the abundance of Allobaculum. Importantly, the study finds that glycerophosphocholine mediates the effect of Bifidobacterium on LDL-C, sphingomyelin mediates the effect of Bifidobacterium on IL-6, and maslinic acid mediates the effect of Allobaculum on IL-6.

CONCLUSION

The results suggest that exogenous POA can improve metabolic disorders and inflammation in HFD-fed mice, potentially by modulating the serum metabolome and gut microbiome.

Exploring Impact of Probiotic-Fermented Soymilk on Dextran-Sulfate-Sodium-Induced Ulcerative Colitis via Modulating Inflammation and Gut Microbiota Profile

SCOPE

Lactic acid bacteria with probiotic functions and their fermentation products play a role in regulating ulcerative colitis (UC). This study investigates the potential role of fermented soymilk (FSM4) rich in isoflavones on DSS-induced UC.

METHODS AND RESULTS

Mice received 3% DSS and are supplemented daily once for 1 week by NFSM and FSM4. DSS usually causes intestinal inflammation and alters the gut microbiota. FSM4 intervention improves the UC-related inflammation and gut microbiota alteration. It considerably decreases pro-inflammatories such as TNF-α, IL-1β, and IL-6 in serum and COX-2 and MPO in colon tissues and pathogenic bacteria (Escherichia-Shigella). This facilitates gut-healthy bacteria growth. These healthy bacteria negatively correlat with pro-inflammatory factors but positively associated with acetic acid, butyric acid, and propionic acid, which may act for PPAR-γ pathway activating and NF-κB p65 pathway inhibiting, lowering the risk of UC. Overall, FSM4 might alleviate UC and significantly reverse the dysbiosis of gut microbiota via the PPAR-γ activation. It could be a good alternative for developing functional food to protect against UC.

CONCLUSION

FSM4 attenuates intestinal inflammation and modulates the SCFA-producing bacteria growth, which enable the PPAR-γ activation to alleviate the UC target, which could be a dietary intervention strategy for gut health.

The impact of gut microbial signals on hematopoietic stem cells and the bone marrow microenvironment

Hematopoietic stem cells (HSCs) undergo self-renewal and differentiation in the bone marrow, which is tightly regulated by cues from the microenvironment. The gut microbiota, a dynamic community residing on the mucosal surface of vertebrates, plays a crucial role in maintaining host health. Recent evidence suggests that the gut microbiota influences HSCs differentiation by modulating the bone marrow microenvironment through microbial products. This paper comprehensively analyzes the impact of the gut microbiota on hematopoiesis and its effect on HSCs fate and differentiation by modifying the bone marrow microenvironment, including mechanical properties, inflammatory signals, bone marrow stromal cells, and metabolites. Furthermore, we discuss the involvement of the gut microbiota in the development of hematologic malignancies, such as leukemia, multiple myeloma, and lymphoma.

Effects of Astragaloside IV on Hearing, Inflammatory Factors, and Intestinal Flora in Mice Exposed to Noise

Long-term exposure to noise can cause irreversible hearing loss. Considering that there is no effective drug treatment, it is important to seek preventive treatment for noise-induced hearing loss (NIHL). Although astragaloside IV (AS-IV) protects against NIHL by reducing serum inflammatory factors, there is scarce information on the regulation of inflammatory factors by AS-IV to prevent NIHL. We investigated the hearing thresholds and relationship between the serum levels of inflammatory cytokines and intestinal microbiota of c57bl/6j mice exposed to noise (103 dB SPL 4 h·d-1) for 7 days, treated with or without AS-IV. Our results revealed a lower hearing threshold and lower serum levels of TNF-α, TNF-γ, IL-6, IL-1β, and IFN-γ in the mice treated with AS-IV. Additionally, AS-IV increased the abundance levels of the phylum Firmicutes, class Bacillus, order Lactobacillus, and family Lactobacillus (p < 0.05), and decreased those of the phylum Bacteroidetes and order Bacteroidales (p < 0.05). Lactobacillus and Bacilli negatively correlated with TNF-α, TNF-γ, and IL-1β; Erysipelotrichaceae negatively correlated with INF-γ; and Clostridiales positively correlated with IL-1β. In conclusion, AS-IV reduces the elevation of hearing thresholds in mice, preventing hearing loss in mice exposed to noise, and under the intervention of AS-IV, changes in the levels of inflammatory factors correlate with intestinal flora. We suggest that AS-IV improves intestinal flora and reduces inflammation levels in c57bl/6j mice exposed to noise.

Gut-derived ammonia contributes to alcohol-related fatty liver development via facilitating ethanol metabolism and provoking ATF4-dependent de novo lipogenesis activation

BACKGROUND & AIMS

Dysbiosis contributes to alcohol-associated liver disease (ALD); however, the precise mechanisms remain elusive. Given the critical role of the gut microbiota in ammonia production, we herein aim to investigate whether and how gut-derived ammonia contributes to ALD.

METHODS

Blood samples were collected from human subjects with/without alcohol drinking. Mice were exposed to the Lieber-DeCarli isocaloric control or ethanol-containing diets with and without rifaximin (a nonabsorbable antibiotic clinically used for lowering gut ammonia production) supplementation for five weeks. Both in vitro (NH4Cl exposure of AML12 hepatocytes) and in vivo (urease administration for 5 days in mice) hyperammonemia models were employed. RNA sequencing and fecal amplicon sequencing were performed. Ammonia and triglyceride concentrations were measured. The gene and protein expression of enzymes involved in multiple pathways were measured.

RESULTS

Chronic alcohol consumption causes hyperammonemia in both mice and human subjects. In healthy livers and hepatocytes, ammonia exposure upregulates the expression of urea cycle genes, elevates hepatic de novo lipogenesis (DNL), and increases fat accumulation. Intriguingly, ammonia promotes ethanol catabolism and acetyl-CoA formation, which, together with ammonia, synergistically facilitates intracellular fat accumulation in hepatocytes. Mechanistic investigations uncovered that ATF4 activation, as a result of ER stress induction and general control nonderepressible 2 activation, plays a central role in ammonia-provoked DNL elevation. Rifaximin ameliorates ALD pathologies in mice, concomitant with blunted hepatic ER stress induction, ATF4 activation, and DNL activation.

CONCLUSIONS

An overproduction of ammonia by gut microbiota, synergistically interacting with ethanol, is a significant contributor to ALD pathologies.

Structural elucidation of a highly branched α-D-glucan from Huangjiu and its hepatoprotective activity via gut microbiome regulation and intestinal barrier repairment

Polysaccharides in Huangjiu, a traditional fermented food, are expected to be potentially effective ingredients in protecting against alcoholic liver disease (ALD). Elucidating their precise structural and functional characteristics is essential for in-depth understanding of structure-activity relationships of hepatoprotective polysaccharides. Herein, a major polysaccharide component HJPS1-2 was purified from Huangjiu with an average molecular weight of 3.49 kDa. Structural analyses inferred that HJPS1-2 backbone was composed of (1 → 4)-linked α-D-Glcp and a single α(1 → 6)-D-Glcp-α(1 → 6)-D-Glcp branched unit for every three α(1 → 4)-D-Glcp. An ALD mouse model was further established to clarify the underlying effect of HJPS1-2 on ALD alleviation. Biochemical detection and histopathological assessment revealed that HJPS1-2 intervention remarkably improved ethanol-induced hepatic dysfunction and steatosis. HJPS1-2 treatment ameliorated gut microbiota dysbiosis of ALD mice in a dose-dependent manner, mainly manifested as restoration of microbial diversities, community structure and bacterial interaction patterns. Compared with ethanol group, the strikingly elevated intestinal short-chain fatty acids' levels and enhanced intestinal barrier function after HJPS1-2 intake might contribute to reduced serum and liver lipopolysaccharide levels and subsequently suppressed release of hepatic inflammatory cytokines, thus mitigating ALD. Collectively, this research supports the potential of food-derived polysaccharides to hinder the early formation and progression of ALD through maintaining intestinal homeostasis.

Pan C, Xing H. Intestinal microbiome-targeted therapies improve liver function in alcohol-related liver disease by restoring bifidobacteria: a systematic review and meta-analysis

Objective: To systematically evaluate the efficacy of intestinal microbiome-targeted therapies (MTTs) in alcohol-related liver disease (ALD). Methods: With pre-specified keywords and strategies, we searched databases including Cochrane Library, PubMed, EMBASE, CNKI, Wanfang Data, and Weipu for RCTs on intestinal MTTs in ALD patients from January 2000 to May 2021. Two researchers independently conducted literature screening, data extraction, and quality evaluation according to the eligible criteria. Outcomes of interest included the effects of intestinal MTTs on ALT, AST, GGT, TBIL, TNF-α, IL-6, intestinal Escherichia coli, and Bifidobacteria when compared to the control group. Pooled data were compiled and analyzed with Revman 5.4 software. Results: Among 5 RCTs included with 456 ALD patients who received probiotics, the therapeutic pooled effects in the experimental group were the followings: ALT (MD = -7.16.95% CI: 10.71∼-3.60; p < 0.0001)、AST (MD = -25.11.95% CI: 30.57∼-19.47; p < 0.00001)、GGT (MD = -6.72.95% CI: 11.91∼-1.53; p = 0.01)、IL-6(SMD = -0.82.95% CI: 1.10∼-0.54; p < 0.00001), which were significantly better than those in the placebo or standard treatment group respectively, while the difference of TBIL (SMD = -0.06, 95%CI: 0.29-0.16; p = 0.59), TNF-α(SMD = -0.53.95% CI: 1.57-0.50; p = 0.31)in the two groups was not significant. After intestinal MTT treatment, the number of intestinal Bifidobacteria increased significantly (MD = 0.79.95% CI: 0.00-1.58; p = 0.05)in the experimental group. However, there were no significant changes in the number of E. coli in both groups (SMD = -0.29.95% CI: 0.92-0.34; p = 0.36). Conclusion: Intestinal MTTs can significantly improve liver function, associated with the increase of intestinal Bifidobacteria, which may be beneficial to ALD. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021246067, Identifier CRD42021246067.

MUP1 mediates urolithin A alleviation of chronic alcohol-related liver disease via gut-microbiota-liver axis

Alcohol-related liver disease (ALD) is recognized as a global health crisis, contributing to approximately 20% of liver cancer-associated fatalities. Dysbiosis of the gut microbiome is associated with the development of ALD, with the gut microbial metabolite urolithin A (UA) exhibiting a potential for alleviating liver symptoms. However, the protective efficacy of UA against ALD and its underlying mechanism mediated by microbiota remain elusive. In this study, we provide evidence demonstrating that UA effectively ameliorates alcohol-induced metabolic disorders and hepatic endoplasmic reticulum (ER) stress through a specific gut-microbiota-liver axis mediated by major urinary protein 1 (MUP1). Moreover, UA exhibited the potential to restore alcohol-induced dysbiosis of the intestinal microbiota by enriching the abundance of Bacteroides sartorii (B. sartorii), Parabacteroides distasonis (P. distasonis), and Akkermansia muciniphila (A. muciniphila), along with their derived metabolite propionic acid. Partial attenuation of the hepatoprotective effects exerted by UA was observed upon depletion of gut microbiota using antibiotics. Subsequently, a fecal microbiota transplantation (FMT) experiment was conducted to evaluate the microbiota-dependent effects of UA in ALD. FMT derived from mice treated with UA exhibited comparable efficacy to direct UA treatment, as it effectively attenuated ER stress through modulation of MUP1. It was noteworthy that strong associations were observed among the hepatic MUP1, gut microbiome, and metabolome profiles affected by UA. Intriguingly, oral administration of UA-enriched B. sartorii, P. distasonis, and A. muciniphila can enhance propionic acid production to effectively suppress ER stress via MUP1, mimicking UA treatment. Collectively, these findings elucidate the causal mechanism that UA alleviated ALD through the gut-microbiota-liver axis. This unique mechanism sheds light on developing novel microbiome-targeted therapeutic strategies against ALD.

The Protective Effect of Auricularia cornea var. Li. Polysaccharide on Alcoholic Liver Disease and Its Effect on Intestinal Microbiota

This study's objective was to examine the protective effect and mechanism of a novel polysaccharide (AYP) from Auricularia cornea var. Li. on alcoholic liver disease in mice. AYP was extracted from the fruiting bodies of Auricularia cornea var. Li. by enzymatic extraction and purified by DEAE-52 and Sephacryl S-400. Structural features were determined using high-performance liquid chromatography, ion exchange chromatography and Fourier-transform infrared analysis. Additionally, alcoholic liver disease (ALD) mice were established to explore the hepatoprotective activity of AYP (50, 100 and 200 mg/kg/d). Here, our results showed that AYP presented high purity with a molecular weight of 4.64 × 105 Da. AYP was composed of galacturonic acid, galactose, glucose, arabinose, mannose, xylose, rhamnose, ribos, glucuronic acid and fucose (molar ratio: 39.5:32.9:23.6:18.3:6.5:5.8:5.8:3.3:2:1.1). Notably, AYP remarkably reduced liver function impairment (alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG), total cholesterol (TC)), nitric oxide (NO) and malondialdehyde (MDA) of the liver and enhanced the activity of antioxidant enzymes (superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and glutathione (gGSH)) in mice with ALD. Meanwhile, the serum level of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) were reduced in ALD mice treated by AYP. Furthermore, the AYPH group was the most effective and was therefore chosen to further investigate its effect on the intestinal microbiota (bacteria and fungi) of ALD mice. Based on 16s rRNA and ITS-1 sequencing data, AYP influenced the homeostasis of intestinal microbiota to mitigate the damage of ALD mice, possibly by raising the abundance of favorable microbiota (Muribaculaceae, Lachnospiraceae and Kazachstania) and diminishing the abundance of detrimental microbiota (Lactobacillus, Mortierella and Candida). This discovery opens new possibilities for investigating physiological activity in A. cornea var. Li. and provides theoretical references for natural liver-protecting medication research.

Yak milk protects against alcohol-induced liver injury in rats

The protective effects of yak milk (YM) against chronic alcoholic liver injury in rats were investigated in this study. Histologic and biochemical analyses demonstrated that YM consumption ameliorates alcohol-induced liver injury by increasing the liver antioxidant enzyme activity and reducing inflammation. Furthermore, microbiome and metabolomic analyses exploring YM's impact on gut microbiota and metabolism found that YM administration regulates gut microbiota composition. Specifically, there was a decrease in the relative abundance of Helicobacter, Streptococcus, Peptococcus and Tyzzerella, along with an increase in Turisibacter and Intestinimonas. Moreover, Pearson analysis indicated positive correlations between Peptococcus and Tyzzerella with ALT and AST levels, while showing a negative correlation with ADH levels. Furthermore, differential metabolite analysis of fecal samples from the YM group identified significant increases in the taurine (2-Aminoethanesulfonic acid), hypotaurine (2-Aminoethanesulfonic Acid) and isethionic acid levels. Finally, KEGG topology analysis highlighted taurine and hypotaurine metabolism as the primary pathways influenced by YM intervention. Therefore, these findings collectively suggest that YM may protect alcohol-exposed rats against liver injury by modulating oxidative stress, inflammatory response, gut microbiota disorder, and metabolic regulation.

Oral Pathogenic Bacteria and the Oral-Gut-Liver Axis: A New Understanding of Chronic Liver Diseases

Liver diseases have long been a prevalent cause of morbidity and mortality, and their development and progression involve multiple vital organs throughout the body. Recent studies on the oral-gut-liver axis have revealed that the oral microbiota is associated with the pathophysiology of chronic liver diseases. Since interventions aimed at regulating oral biological disorders may delay the progress of liver disease, it is crucial to better comprehend this process. Oral bacteria with potential pathogenicity have been extensively studied and are closely related to several types of chronic liver diseases. Therefore, this review will systemically describe the emerging role of oral pathogenic bacteria in common liver diseases, including alcoholic liver disease (ALD), non-alcoholic steatohepatitis (NASH), non-alcoholic fatty liver disease (NAFLD), cirrhosis, autoimmune liver diseases (AILD), and liver cancer, and bring in new perspectives for future research.

The role of NADPH oxidase 1 in alcohol-induced oxidative stress injury of intestinal epithelial cells

Alcohol-mediated reactive oxygen species (ROS) play a vital role in intestinal barrier injury. However, the mechanism of ROS accumulation in enterocytes needs to be explored further. In our study, we found that chronic-binge ethanol-fed mice had increased levels of gut oxidative stress and high intestinal permeability. The transcription profiles of the colonic epithelial cells showed that the level of NADPH oxidase 1 (NOX1) was significantly elevated in alcohol-exposed mice compared with isocaloric-exposed mice. In vitro, NOX1 silencing alleviated ROS accumulation and the apoptosis of human colonic epithelial cells (NCM460), while NOX1 overexpression accelerated oxidative stress injury of NCM460 cells. Propionic acid was reduced in the gut of chronic-binge ethanol-fed mice, compared with isocaloric-fed mice, as observed through untargeted metabolomic analysis. Supplementation with propionate relieved ethanol-induced liver and intestinal barrier injuries and reduced the level of ROS accumulation and apoptosis of ethanol-induced colonic epithelial cells. Propionate alleviating NOX1 induced ROS injury of colonic epithelial cells, independent of G protein-coupled receptors. Propionate significantly inhibited histone deacetylase 2 (HDAC2) expressions both in ethanol-exposed colonic epithelial cells and TNF-α-treated NCM460. Chromatin immunoprecipitation (ChIP) assays showed that propionate suppressed the NOX1 expression by regulating histone acetylation in the gene promoter region. In conclusion, NOX1 induces oxidative stress injury of colonic epithelial cells in alcohol-related liver disease. Propionate, which can act as an endogenous HDAC2 inhibitor, can decrease levels of apoptosis of intestinal epithelial cells caused by oxidative stress.

Compensated liver cirrhosis: Natural course and disease-modifying strategies

Compensated liver cirrhosis (CLC) is defined as cirrhosis with one or more decompensating events, such as ascites, variceal haemorrhage, or hepatic encephalopathy. Patients with CLC are largely asymptomatic with preserved hepatic function. The transition from CLC to decompensated cirrhosis occurs as a result of a complex interaction between multiple predisposing and precipitating factors. The first decompensation event in CLC patients is considered a significant turning point in the progression of cirrhosis, as it signals a drastic decline in median survival rates from 10-12 years to only 1-2 years. Furthermore, early cirrhosis has the potential to regress as liver fibrosis is a dynamic condition. With the advent of effective non-invasive tools for detecting hepatic fibrosis, more and more patients with CLC are currently being recognised. This offers clinicians a unique opportunity to properly manage such patients in order to achieve cirrhosis regression or, at the very least, prevent its progression. There are numerous emerging approaches for preventing or delaying decompensation in CLC patients. A growing body of evidence indicates that treating the underlying cause can lead to cirrhosis regression, and the use of non-selective beta-blockers can prevent decompensation by lowering portal hypertension. Additionally, addressing various cofactors (such as obesity, diabetes, dyslipidaemia, and alcoholism) and precipitating factors (such as infection, viral hepatitis, and hepatotoxic drugs) that have a detrimental impact on the natural course of cirrhosis may benefit patients with CLC. However, high-quality data must be generated through well-designed and adequately powered randomised clinical trials to validate these disease-modifying techniques for CLC patients. This article discussed the natural history of CLC, risk factors for its progression, and therapeutic approaches that could alter the trajectory of CLC evolution and improve outcomes.

Alcohol consumption promotes arsenic absorption but reduces tissue arsenic accumulation in mice

Alcohol consumption alters gut microflora and damages intestinal tight junction barriers, which may affect arsenic (As) oral bioavailability. In this study, mice were exposed to arsenate in the diet (6 μg/g) over a 3-week period and gavaged daily with Chinese liquor (0.05 or 0.10 mL per mouse per day). Following ingestion, 78.0% and 72.9% of the total As intake was absorbed and excreted via urine when co-exposed with liquor at daily doses of 0.05 or 0.10 mL, significantly greater than when As was supplied alone (44.7%). Alcohol co-exposure significantly altered gut microbiota but did not significantly alter As biotransformation in the intestinal tract or tissue. Significantly lower relative mRNA expression was observed for genes encoding for tight junctions in the ileum of liquor co-exposed mice, contributing to greater As bioavailability attributable to enhanced As absorption via the intestinal paracellular pathway. However, As concentration in the liver, kidney, and intestinal tissue of liquor-treated mice was decreased by 24.4%-42.6%, 27.5%-38.1%, and 28.1%-48.9% compared to control mice. This was likely due to greater renal glomerular filtration rate induced by alcohol, as suggested by significantly lower expression of genes encoding for renal tight junctions. In addition, in mice gavaged daily with 0.05 mL liquor, the serum antidiuretic hormone level was significantly lower than control mice (2.83 ± 0.59 vs. 5.40 ± 1.10 pg/mL), suggesting the diuretic function of alcohol consumption, which may facilitate As elimination via urine. These results highlight that alcohol consumption has a significant impact on the bioavailability and accumulation of As.

Lactiplantibacillus plantarum P101 Attenuated Cyclophosphamide-Induced Liver Injury in Mice by Regulating the Nrf2/ARE Signaling Pathway

Cyclophosphamide causes side effects in cancer patients, including hepatotoxicity. Probiotics have recently emerged as potential approaches for the administration of many diseases. This study aimed to evaluate the protective effects of Lactiplantibacillus plantarum P101 against cyclophosphamide-induced liver injury and elucidate the underlying mechanism. In this study, Lactiplantibacillus plantarum P101 or Lactobacillus rhamnosus GG were pre-administered to mice with varying duration (1 week, 2 weeks, and 3 weeks) before being intraperitoneally injected with cyclophosphamide at a dose of 30 mg/kg/day for 7 days to induce liver injury. Results demonstrated that cyclophosphamide-induced liver injury was characterized by histopathological disorders, including irregular central venous shape and hepatic vascular rupture, as well as a severe inflammation response and oxidative stress. The administration of probiotics for 3 weeks exerted the most significant improvements in alleviating liver injury, oxidative stress, and inflammation when compared to the shorter intervention duration. Notably, Lactiplantibacillus plantarum P101 exhibited more pronounced effects than Lactobacillus rhamnosus GG. Furthermore, Lactiplantibacillus plantarum P101 enhanced the antioxidant defense system by activating the Nrf2/ARE signaling pathway, ultimately alleviating hepatotoxicity and hepatocyte apoptosis. In conclusion, this study highlighted the potential of Lactiplantibacillus plantarum P101 to alleviate cyclophosphamide-induced hepatotoxicity.

Roles of Gut Microbiota in Alcoholic Liver Disease

Alcoholic liver disease (ALD)-one of the most common liver diseases - involves a wide range of disorders, including asymptomatic hepatic steatosis, alcoholic hepatitis (AH), liver fibrosis, and cirrhosis. Alcohol consumption induces a weakened gut barrier and changes in the composition of the gut microbiota. The presence of CYP2E1 and its elevated levels in the gastrointestinal tract after alcohol exposure lead to elevated levels of ROS and acetaldehyde, inducing inflammation and oxidative damage in the gut. At the same time, the influx of harmful molecules such as the bacterial endotoxin LPS and peptidogly from gut dysbiosis can induce intestinal inflammation and oxidative damage, further compromising the intestinal mucosal barrier. In this process, various oxidative stress-mediated post-translational modifications (PTMs) play an important role in the integrity of the barrier, eg, the presence of acetaldehyde will result in the sustained phosphorylation of several paracellular proteins (occludin and zona occludens-1), which can lead to intestinal leakage. Eventually, persistent oxidative stress, LPS infiltration and hepatocyte damage through the enterohepatic circulation will lead to hepatic stellate cell activation and hepatic fibrosis. In addition, probiotics, prebiotics, synbiotics, fecal microbial transplantation (FMT), bioengineered bacteria, gut-restricted FXR agonists and others are promising therapeutic approaches that can alter gut microbiota composition to improve ALD. In the future, there will be new challenges to study the interactions between the genetics of individuals with ALD and their gut microbiome, to provide personalized interventions targeting the gut-liver axis, and to develop better techniques to measure microbial communities and metabolites in the body.

Protection of Inonotus hispidus (Bull.) P. Karst. against Chronic Alcohol-Induced Liver Injury in Mice via Its Relieving Inflammation Response

Alcoholic liver disease (ALD) can be induced by excessive alcohol consumption, and has a worldwide age-standardized incidence rate (ASIR) of approximately 5.243%. Inonotus hispidus (Bull.) P. Karst. (IH) is a mushroom with pharmacological effects. In ALD mice, the hepatoprotective effects of IH were investigated. IH strongly ameliorated alcohol-induced pathological changes in the liver, including liver structures and its function-related indices. Intestinal microbiota and serum metabolomics analysis showed that IH altered the associated anti-inflammatory microbiota and metabolites. According to results obtained from Western blot, immunohistochemistry (IHC), and enzyme-linked immunosorbent assay (ELISA), IH downregulated the levels of pro-inflammation factors interleukin (IL)-1β, IL-6 and tumor necrosis factor-α (TNF-α), enhanced the expressions of peroxisome proliferator-activated receptor alpha (PPARα) and 15-hydroxprostaglandin dehydrogenase (15-PGDH), and inhibited the phosphorylated activation of Janus kinase (JAK) 1 and signal transducer and activator of transcription (STAT) 3, confirming the hepatoprotection of IH against alcohol damage via anti-inflammation. This study provides the experimental evidence for the hepatoprotective effects of IH in chronic ALD.

Gut Microbiome-Centered Therapies for Alcohol-Associated Liver Disease

Globally, liver disease caused by alcohol is becoming more prevalent each year. Misuse of alcohol causes a spectrum of liver diseases, such as liver steatosis, steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. The cornerstone of treatment is abstinence from alcohol. In spite of this, available treatment for alcohol-associated liver disease (ALD) shows limited effectiveness currently. There are numerous ways in which alcohol disrupts the gut-liver axis, including dysbiosis of the gut microbiome, disruption of mucus and epithelial cell barriers, impaired production of antimicrobial molecules, and dysfunction of the immune system, causing translocation of viable microbes and microbial products to the liver and systemic circulation. Microbial exposure results in not only inflammation and progression of liver disease but also infections in late-stage ALD. This led scientists to focus their therapeutic strategies and targets for ALD on the gut microbiome. Throughout this review, we address the role of gut microbiome-centered therapeutic approaches for ALD focusing predominantly on randomized controlled trials. We will summarize the latest clinical trials using probiotics, antibiotics, and fecal microbial transplants in modulating the gut-liver axis and for improvement of ALD.

Effects of dietary irritants on intestinal homeostasis and the intervention strategies

Abundant diet components are unexplored as vital factors in intestinal homeostasis. Dietary irritants stimulate the nervous system and provoke somatosensory responses, further inducing diarrhea, gut microbiota disorder, intestinal barrier damage or even severe gastrointestinal disease. We depicted the effects of food with piquancy, high fat, low pH, high-refined carbohydrates, and indigestible texture. The mechanism of dietary irritants on intestinal homeostasis were comprehensively summarized. Somatosensory responses to dietary irritants are palpable and have specific chemical and neural mechanisms. In contrast, even low-dose exposure to dietary irritants can involve multiple intestinal barriers. Their mechanisms in intestinal homeostasis are often overlapping and dose-dependent. Therefore, treating symptoms caused by dietary irritants requires personalized nutritional advice. The reprocessing of stimulant foods, additional supplementation with probiotics or prebiotics, and enhancement of the intestinal barrier are effective intervention strategies. This review provides promising preliminary guidelines for the treatment of symptoms and gastrointestinal injury caused by dietary irritants.

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.

Bacillus subtilis pretreatment alleviates ethanol-induced acute liver injury by regulating the Gut-liver axis in mice

This study was designed to investigate the hepatoprotective effects of Bacillus subtilis, a commensal bacterial species in the human gut, on ethanol-induced acute liver damage and the underlying mechanisms in mice. Male ICR mice challenged with three doses of ethanol (5.5 g/kg BW) exhibited a significant increase in serum aminotransferase activities and TNF-α level, liver fat accumulation, and activation of NF-κB signaling and NLRP3 inflammasome, which was suppressed by pretreatment with Bacillus subtilis. Besides, Bacillus subtilis inhibited acute ethanol-induced intestinal villi shortening and epithelial loss, the decline of protein levels of intestinal tight junction protein ZO-1 and occludin, and elevation of serum LPS level. Furthermore, the upregulation of mucin-2 (MUC2) and the downregulation of anti-microbial Reg3B and Reg3G levels induced by ethanol were repressed by Bacillus subtilis. Lastly, Bacillus subtilis pretreatment significantly increased the abundance of the intestinal Bacillus, but had no effects on the binge drinking-induced increase of Prevotellaceae abundance. These results demonstrate that Bacillus subtilis supplementation could ameliorate binge drinking-induced liver injury, and thus may serve as a functional dietary supplement for binge drinkers.

Dietary cholesterol in alcohol-associated liver disease

There is an increasing prevalence of alcohol-associated liver disease (ALD) worldwide. In addition to excessive alcohol consumption, other nutritional factors have been shown to affect the initiation and progression of ALD. The emerging role of cholesterol in exacerbating ALD has been reported recently and the underlying mechanisms are discussed. In addition, the interplay between dietary cholesterol and alcohol on cholesterol metabolism is reviewed. Furthermore, we highlight the therapeutic potential of cholesterol-lowering drugs in managing the onset and severity of ALD. Finally, we suggest the future mechanistic investigation of the effect of cholesterol on insulin resistance and intestinal inflammation in the exacerbation of alcohol-induced cellular and systemic dysfunction.

Tandem mass tag-based quantitative proteomics analyses of a chicken-original virulent and its attenuated Histomonas meleagridis strain in China

Introduction

Histomonas meleagridis can cause histomonosis in poultry. Due to the prohibition of effective drugs, the prevention and treatment of the disease requires new strategies. Questions about its pathogenic mechanisms and virulence factors remain puzzling.

Methods

To address these issues, a tandem mass tag (TMT) comparative proteomic analysis of a virulent strain and its attenuated strain of Chinese chicken-origin was performed.

Results

A total of 3,494 proteins were identified in the experiment, of which 745 proteins were differentially expressed (fold change ≥1.2 or ≤0.83 and p &lt; 0.05), with 192 up-regulated proteins and 553 down-regulated proteins in the virulent strain relative to the attenuated strain.

Discussion

Surface protein BspA like, digestive cysteine proteinase, actin, and GH family 25 lysozyme were noted among the proteins up regulated in virulent strains, and these several proteins may be directly related to the pathogenic capacity of the histomonad. Ferredoxin, 60S ribosomal protein L6, 40S ribosomal protein S3, and NADP-dependent malic enzyme which associated with biosynthesis and metabolism were also noted, which have the potential to be new drug targets. The up-regulation of alpha-amylase, ras-like protein 1, ras-like protein 2, and involucrin in attenuated strains helps to understand how it is adapted to the long-term in vitro culture environment. The above results provide some candidate protein-coding genes for further functional verification, which will help to understand the molecular mechanism of pathogenicity and attenuation of H. meleagridis more comprehensively.