Parabacteroides distasonis ameliorates hepatic fibrosis potentially via modulating intestinal bile acid metabolism and hepatocyte pyroptosis in male mice

Co-exposure to enrofloxacin and atrazine enhances the hepatotoxicity in Larimichthys crocea by targeting the hypothalamic-pituitary-thyroid and gut-liver axes

Enrofloxacin (ENR) and atrazine (ATZ) are common co-contaminants in marine environments. Although the immunosuppressive effects of ENR and the endocrine-disrupting properties of ATZ are well established, the combined effects of these pollutants on hepatotoxicity, particularly concerning the regulation of the hypothalamic-pituitary-thyroid (HPT) and gut-liver axes, remain poorly understood. In this study, Larimichthys crocea was exposed to ENR and ATZ at environmentally relevant concentrations, individually and in combination, to investigate the hepatotoxicity. Liver cell swelling, necrosis, oxidative stress, and elevated liver injury markers were observed, indicating hepatic damage, with co-exposure exacerbating liver injury. Decreased levels of thyrotropin-releasing hormone and thyroid-stimulating hormone, increased triiodothyronine and thyroxine, and altered expression of HPT axis-related genes demonstrated enhanced disruption of the HPT axis under co-exposure, which was strongly associated with oxidative stress and liver dysfunction. Molecular docking confirmed that ENR and ATZ inhibited thyroid hormone binding to target proteins, likely provoking the enhanced hepatotoxicity. Additionally, ATZ significantly intensified the intestinal bacterial disturbances induced by ENR, further aggravating hepatotoxicity through the gut-liver axis. This study is the first to reveal the increased risk associated with ENR and ATZ co-exposure, highlighting the need for attention to such co-contaminants.

Parabacteroides distasonis promotes CXCL9 secretion of tumor-associated macrophages and enhances CD8+T cell activity to trigger anti-tumor immunity against anti-PD-1 treatment in non-small cell lung cancer mice

BACKGROUND

Parabacteroides distasonis (P. distasonis) could regulate inflammatory markers, promote intestinal barrier integrity, and block tumor formation in colon. However, the regulatory effect of P. distasonis on non-small cell lung cancer (NSCLC) remains unknown. This study aimed to investigate the regulatory effect of P. distasonis on NSCLC and its impact on tumor immunity.

METHODS

We first established a mouse model of Lewis lung cancer, and administered P. distasonis and intrabitoneal injection of anti-mouse PD-1 monoclonal antibody to assess the impact of P. distasonis on tumor immunity, and mouse intestinal barrier. Then, we explored the effect of P. distasonis on CD8+T cells and CXCL9 secretion mediated by tumor-associated macrophages (TAM). We used the TLR1/2 complex inhibitor CPT22 to evaluate its effect on macrophage activation. Finally, we explored the effect of P. distasonis on CD8+T cells and CXCL9 secreted by TAM in vivo.

RESULTS

In vivo, P. distasonis enhanced anti-tumor effects of anti-PD-1 in NSCLC mice, improved intestinal barrier integrity, recruited macrophages, and promoted M1 polarization. In vitro, CD86 and iNOS levels in BMDM were elevated and CD206 and Arg1 levels were suppressed in membrane fraction of P. distasonis (PdMb) group in comparison to Control group. With additional CPT22 pre-treatment, the levels of CD86 and iNOS in BMDM were reduced, and the levels of CD206 and Arg1 were increased. Compared to PBS group, P. distasonis group exhibited higher proportion of CD8+T cells in tumor tissues, along with increased positive proportion of GZMB and IFN-γ in CD8+T cells. Additionally, in comparison to Control group, PdMb group showed an elevated proportion of GZMB+T and IFN-γ+T cells within CD8+T cells, and secretion of IFN-γ, TNF-α, perforin, and GZMB in CD8+T cell supernatant increased. Moreover, the proportion of CXCL9+F4/80+ macrophages in tumor tissues was higher in P. distasonis group compared to PBS group. In comparison to Control group, CXCL9 protein level in BMDM and CXCL9 secretion level in BMDM supernatant were increased in PdMb group. Finally, P. distasonis enhanced CD8+T cell activity by secreting CXCL9 from macrophages in vivo.

CONCLUSIONS

P. distasonis promoted CXCL9 secretion of TAM and enhanced CD8+T cell activity to trigger anti-tumor immunity against anti-PD-1 treatment in NSCLC mice.

Diet shapes and maintains the personalized native gut microbiomes in mice

BACKGROUND

The gut microbiome plays a critical role in human health and disease. Different dietary backgrounds play an important role in the uniqueness and diversity of the gut microbiota in different individuals, which promotes heterogeneity in disease phenotypes and treatment responses. Here, we explored how diet affects the composition and function of the native gut microbiome of model mice, based on the shotgun metagenomic and metabolomic, by analyzing the gut microbiome of C57B/6J mice in different dietary backgrounds.

RESULTS

The gut microbiomes of mice receiving different diets consistently exhibit distinct compositions across bacterial species, strains, fungi and phages. This implies that native microbial communities cannot 'homogenize' rapidly becaise of priority effects and unchanging diets. Notably, hotspot bacteria such as Limosilactobacillus reuteri, Parabacteroides distasonis and Akkermansia muciniphila were significantly different among the groups. These species harbor diverse adaptive mutations, reflecting genomic evolutionary diversity. The functional profiles of the gut microbiota also exhibit selective differences, involving the capacity for carbohydrate, branched-chain amino acid and fatty acid synthesis, as well as virulence factors, carbohydrate-active enzymes and antibiotic resistance. Furthermore, the differences in the gut microbiota also propagate to the host's serum, where structural and specific metabolite differences were observed. Metabolites that directly impact host health, such as d-glucosamine 6-phosphate and testolic acid, also show significant differences between the different dietary groups.

CONCLUSION

Our findings underscore the profound influence of different dietary the composition and functionality of the gut microbiome, offering valuable insights into optimizing health outcomes through personalized nutritional interventions. © 2024 Society of Chemical Industry.

FAP-catalyzed in situ self-assembly of magnetic resonance imaging probe for early and precise staging of liver fibrosis

Liver fibrosis is an inevitable stage in the progression of most chronic liver diseases. Early diagnosis and treatment of liver fibrosis are crucial for effectively managing chronic liver conditions. However, there lacks a noninvasive and sensitive imaging method capable of early assessing fibrosis activity. Here, we report a molecular magnetic resonance imaging (MRI) probe for imaging fibroblast activation protein (FAP), which is overexpressed on activated hepatic stellate cells (HSCs) even in very early fibrotic livers. This method relies on FAP-catalyzed in situ self-assembly of its substrate probe that leads to the increase of the rotational correlation time (τR) of probe, thereby notably amplifies T1 MRI signal. Thanks to the superior specificity and efficiency of enzymatic reaction, our method has been validated as highly selective and sensitive to FAP in two liver fibrosis mouse models. By establishing a direct correlation between MRI signals and fibrosis activity, our method enables continuous monitoring of liver fibrotic disease progression and assessment of treatment responses.

Polysaccharide from Caulerpa lentillifera alleviates hyperlipidaemia through altering bile acid metabolism mediated by gut microbiota

Polysaccharide from Caulerpa lentillifera (CLP) offers preventative health benefits, but its efficacy against hyperlipidaemia and underlying mechanisms still elusive. This investigation assessed CLP's potential to mitigate high-fat diet (HFD)-induced hyperlipidaemia via the gut microbiota-bile acid (BA) axis. In hyperlipidaemic mice, 8 weeks of CLP treatment improved body weight, lipid profiles, and hepatic function, correlating with shifts in BA concentrations. Additionally, CLP not only repaired HFD-induced gut dysbiosis by increasing SCFA-producing bacteria but also positively modulated gut metabolites, including acetic and butyric acids. Spearman's correlation analysis illustrated strong associations between the altered microbes, metabolites, and the expression of genes involved in BA metabolism. Remarkably, CLP significantly influenced BA levels related to hyperlipidaemia, partly by augmenting the population of Parabacteroides and associated butyric acid level. These results indicate that CLP may serve as a functional food to guard against dyslipidaemia through impacting specific gut microbes and metabolites such as Parabacteroides and butyrate, and thus presenting promising therapeutic prospects for diseases associated with BA metabolism.

Integrating Bioinformatics and Experimental Validation to Identify Mitochondrial Permeability Transition-Driven Necrosis-Related lncRNAs that can Serve as Prognostic Biomarkers and Therapeutic Targets in Endometrial Carcinoma

Endometrial carcinoma (EC) is a common malignant tumor in women with high mortality and relapse rates. Mitochondrial permeability transition (MPT)-driven necrosis is a novel form of programmed cell death. The MPT-driven necrosis related lncRNAs (MRLs) involved in EC development remain unclear. We aimed to predict the outcomes of patients with EC by constructing a novel prognostic model based on MRLs and explore potential molecular functions. A risk prognostic model was developed utilizing multi-Cox regression in conjunction with the Least Absolute Shrinkage and Selection Operator (LASSO) regression algorithm, which was based on MRLs. The predictive efficacy of the model was evaluated through receiver operating characteristic (ROC) curve analysis, as well as nomogram and concordance index (C-index) assessments. Patients were categorized into high- and low-risk groups based on their median risk scores. Notably, the high-risk group exhibited significantly poorer overall survival (OS) outcomes. Gene ontology (GO) and Gene set enrichment analysis (GSEA) demonstrated that Hedgehog and cell cycle pathways were enriched in the high-risk group. Tumor Immune Dysfunction and Exclusion (TIDE) displayed that patients in the high-risk group showed a high likelihood of immune evasion and less effective immunotherapy. A significant disparity in immune function was also observed between two groups. Based on the nine-MRLs, drug sensitivity analysis identified several anticancer drugs with potential efficacy in prognosis. Meanwhile, the results demonstrated that OGFRP1 plays a carcinogenic role by affecting mitochondrial membrane permeability in EC. Therefore, the risk model constructed by nine MRLs could be used to predict the clinical outcomes and therapeutic responses in patients with EC effectively.

Early-life antibiotic exposure aggravates hepatic steatosis through enhanced endotoxemia and lipotoxic effects driven by gut Parabacteroides

Compelling evidence supports a link between early-life gut microbiota and the metabolic outcomes in later life. Using an early-life antibiotic exposure model in BALB/c mice, we investigated the life-course impact of prenatal and/or postnatal antibiotic exposures on the gut microbiome of offspring and the development of metabolic dysfunction-associated steatotic liver disease (MASLD). Compared to prenatal antibiotic exposure alone, postnatal antibiotic exposure more profoundly affected gut microbiota development and succession, which led to aggravated endotoxemia and metabolic dysfunctions. This was primarily resulted from the overblooming of gut Parabacteroides and hepatic accumulation of cytotoxic lysophosphatidyl cholines (LPCs), which acted in conjunction with LPS derived from Parabacteroides distasonis (LPS_PA) to induce cholesterol metabolic dysregulations, endoplasmic reticulum (ER) stress and apoptosis. Integrated serum metabolomics, hepatic lipidomics and transcriptomics revealed enhanced glycerophospholipid hydrolysis and LPC production in association with the upregulation of PLA2G10, the gene controlling the expression of the group X secretory Phospholipase A2s (sPLA2-X). Taken together, our results show microbial modulations on the systemic MASLD pathogenesis and hepatocellular lipotoxicity pathways following early-life antibiotic exposure, hence help inform refined clinical practices to avoid any prolonged maternal antibiotic administration in early life and potential gut microbiota-targeted intervention strategies.

Protein supplementation differentially alters gut microbiota and associated liver injury recovery in mouse model of alcohol-related liver disease

BACKGROUND

Patients with Alcohol-related Liver Disease (ALD) are advised increased protein supplementation. These nutrients are also available to gut microbiota. We evaluated the effects of protein supplementation from two sources, soya (veg) or egg, on gut microbiota modulation and ALD remission.

METHODS

ALD was induced in mice using the Lieber-DeCarli diet and incremental ethanol + thioacetamide (150 mg/kg body-weight,i.p.) twice-a-week. After 8wks, mice were fed standard (std.), egg (ovalbumin) or veg diet (20 % increase protein) for 7days. Biochemical parameters, hepatic proteome and gut microbiota composition were analyzed and correlated to capture liver and intestinal recovery.

RESULTS

Veg-diet decreased hepatic steatosis and fibrosis compared with std diet (83.3 %, p = 0.001 and 75 %, p = 0.01, respectively) or egg-diet (66.6 %, p = 0.03 and 25 %, p = 0.04, respectively). ALT and AST levels reduced by 40 % (p = 0.04) and 27.3 % (p = 0.04), respectively in veg diet compared to egg diet. Veg-diet increased intestinal claudin-3 (61 %, p = 0.02) and occludin (80 %, p = 0.001) compared to egg-diet. Plasma endotoxin levels in veg were reduced by 64 % and 32 % compared to std. (p = 0.04) or egg (p = 0.06). Veg-diet increased beneficial taxa, Lachnospiraceae UCG-006 (8.06-folds, p = 1.64E-25), Prevotellaceae NK3B31 (9.96-folds, p = 1.58E-36), Kurthia (8.11-folds, p = 3.98E-16) and Akkermansia (5.9-folds, p = 5.01E-75), while decreasing pathogenic Roseburia (-3.28-folds, p = 1.60E-06), Klebsiella (-5.7-folds, p = 1.55E-06), Staphylococcus (-5.3-folds, p = 1.62E-12). Hepatic proteome showed an increase in pyruvate, cysteine, methionine metabolism, bile acid biosynthesis, and glycolysis.

CONCLUSION

Alteration in protein alone can affect variable outcomes in ALD, with protein from vegetable sources resulting in enhanced improvement in the gut-liver axis. Vegetable protein-supplemented diet enhances fatty acid beta oxidation and energy metabolism accompanied by improvement in gut-dysbiosis and ALD associated hepatic injury.

Preparation technologies, structural characteristics and biological activities of polysaccharides from bee pollen: A review

Bee pollen, a natural honeybee product, is hailed as a treasure trove of human nutrition. Among the nourishing substances of bee pollen, the constituents with a low molecular weight (such as phenolic acids and flavonoid glycosides) have been extensively studied in the past decades, whereas the polysaccharides with a relatively high molecular weight have received much less attention. To deepen our understanding of bee pollen polysaccharides, this review summarizes the published findings related to their preparation technologies, structural characteristics and biological activities. Among the preparation technologies, ultrasonic-assisted extraction is currently the most effective technology for the recovery of polysaccharides from bee pollen, because ultrasound can crack the pollen exine into fragments and facilitate the release of polysaccharides present in the pollen intine. The preliminary structures, including the molecular weight and monosaccharide composition, of bee pollen polysaccharides have been widely reported, but their fine structures have not fully elucidated. Moreover, bee pollen polysaccharides have antioxidant, immunomodulatory, and antitumor activities, exhibiting potential application in functional foods. Furthermore, bee pollen polysaccharides can modulate the composition of gut microbiota and promote the production of short-chain fatty acids. It is expected that this review can provide inspiration for the development and utilization of bee pollen polysaccharides.

Alpha-aminobutyric acid ameliorates diet-induced metabolic dysfunction-associated steatotic liver disease (MASLD) progression in mice via enhancing AMPK/SIRT1 pathway and modulating the gut-liver axis

Alpha-aminobutyric acid (ABA) is a nonproteinogenic amino acid, a metabolite which could be generated from the metabolism of methionine, threonine, serine and glycine or as a gut-microbiome-derived metabolite. Changes in ABA levels have been embroiled in metabolic dysfunction-associated steatotic liver disease (MASLD) intervention studies, but their relation to MASLD pathogenesis remains unclear. Hence, this present study aimed to investigate the effect of oral ABA supplementation on the progression of a high fat/high cholesterol diet (HFD) induced MASLD mice model. ABA was found to remodel the gut microbiome composition and ameliorate MASLD parameters in HFD-fed mice. ABA mitigated HFD-induced gain in liver weight, hepatic steatosis, insulin resistance, serum and hepatic triglyceride levels, and liver cholesterol levels. Modulation of lipid metabolism was observed in the liver, in which expression of proteins and/or genes involved in de novo lipogenesis were suppressed, while those involved in fatty acid oxidation and autophagy were upregulated together with cellular antioxidant capacity, in addition to the enhancement of the AMPK/SIRT1 pathway. ABA reshaped the gut composition by enriching nine bacterial species, including Helicobacter hepaticus, Desulfovibrio sp. G11, Parabacteroides distasonis, and Bacteroides fragilis, while diminishing the abundance of 16 species, which included four Helicobacter species. KEGG pathway analysis of microbial functions found that ABA impeded secondary bile acid biosynthesis - which was reflected in the faecal BA composition analysis. Notably, ABA also inhibited ileal FXR-Fgf15 signaling, allowing for increased hepatic Cyp7a1 expression to eliminate cholesterol buildup in the liver. Overall, our findings indicate that ABA could be used as a promising therapeutic approach for the intervention of MASLD.

Probiotic Limosilactobacillus reuteri DSM 17938 Alleviates Acute Liver Injury by Activating the AMPK Signaling via Gut Microbiota-Derived Propionate

Limosilactobacillus reuteri DSM 17938 (L. reuteri DSM 17938) was one of the most widely used probiotics in humans for gastrointestinal disorders, but few studies have investigated its role in drug-induced liver injury (DILI). Here, we evaluated the efficacy of L. reuteri DSM 17938 using a mouse model of DILI induced by triptolide. Pregavage of L. reuteri DSM 17938 for 1 week remarkably lowered hepatic inflammatory cytokines level and oxidative stress, with diminished serum alanine transaminase and aspartate aminotransferase levels. Metabolomics and RT-qPCR analysis confirmed its ability in ameliorating TP-disrupted hepatic fatty acid β oxidation. Genome annotation of L. reuteri showed its ability to modulate energy metabolism. Targeted metabolomics demonstrated that L. reuteri DSM 17938 modified the short fatty acid profiles in cecum, especially enhancing propionate levels. Further experiments found that L. reuteri DSM 17938 can activate AMPK signaling by upregulating gut microbiota-derived propionate level, thus restoring impaired mitochondrial biogenesis and energy supply processes to recover energy homeostasis, which leads to diminished ROS production and oxidative stress injury in hepatocytes. Besides, AMPK inhibitor dorsomorphin abolished all the effects on propionate protecting mitochondria and energy metabolism. This study established probiotic therapy of L. reuteri DSM 17938 as a preventive intervention for DILI in clinical. We also revealed that L. reuteri DSM 17938 can activate AMPK signaling by propionate, facilitating a deeper understanding of the action mechanism of L. reuteri DSM 17938 against acute liver injury and contributing to the development of its postbiotics and wider applications.

The impact of different gastrointestinal reconstruction techniques on gut microbiota after gastric cancer surgery

Introduction

Gastric cancer is one of the common malignant tumors in the digestive tract, characterized by high incidence and mortality rates. This is particularly significant in China, where a large proportion of global new cases of gastric cancer and related deaths occur. In recent years, with the continuous development of molecular biology technology, people have gained a deeper understanding of the gastrointestinal microbiome, and studies have shown that it is closely related to the occurrence, development, and therapeutic response of gastric cancer. Although surgical intervention is crucial in significantly extending the survival of gastric cancer patients, the disruption of the balance of the intestinal microbiota caused by surgery itself should not be overlooked, as it may affect postoperative recovery.

Methods

This study was approved by the Biomedical Ethics Committee of Sichuan Mianyang 404 Hospital. A random sampling method was used to select patients who underwent gastric cancer surgery at the hospital from January 2023 to December 2023. All patients signed written informed consent forms. Standardized perioperative management was conducted for the patients in the study, including preoperative preparation, intraoperative handling, and postoperative treatment. Fecal samples were collected from patients before surgery (before bowel preparation) and around one week after surgery for 16S rRNA sequencing analysis, through which differential biomarkers and related functional genes were sought.

Results

The study results indicated that there was no significant difference in the diversity of the gut microbiota between the two groups. Compared with the R-Y group, the DTR surgical method significantly altered the structure of the gut microbiota, affecting the types, quantities, and proportions of intestinal bacteria. Furthermore, the DTR group exhibited poorer postoperative nutritional absorption capacity compared to the R-Y group, as indicated by a lower F/B ratio. The R-Y group showed a richer abundance of Bacteroidetes and a lower abundance of Proteobacteria, as well as a higher F/B ratio after surgery. These findings provide new insights into the changes in the gut microbiota following gastric cancer surgery, which may be of significant importance for postoperative recovery and long-term health management.

Discussion

This study reveals the impact of different gastrointestinal reconstruction techniques on the postoperative gut microbiota of gastric cancer patients, providing new insights into the physiological changes during the postoperative recovery period. Although there was no significant difference in microbial diversity between the DTR group and the R-Y group, the DTR group showed more pronounced changes in microbial structure postoperatively, which may be associated with an increased risk of postoperative infection. These findings emphasize the importance of considering the impact on the gut microbiota when selecting gastric cancer surgery methods. However, the study had a limited sample size and did not delve into changes in metabolites. Future studies should expand the sample size and conduct metabolomic analyses to further validate these preliminary findings.

Signature of pre-pregnancy microbiome in infertile women undergoing frozen embryo transfer with gestational diabetes mellitus

This study aims to evaluate differences in gut microbiota structures between infertile women undergoing frozen embryo transfer (FET) with gestational diabetes mellitus (GDM) and healthy controls (HCs), and to identify potential markers. We comprehensively enrolled 193 infertile women undergoing FET (discovery cohort: 38 HCs and 31 GDM; validation cohort: 85 HCs and 39 GDM). Gut microbial profiles of the discovery cohort were investigated during the pre-pregnancy (Pre), first trimester (T1), and second trimester (T2). The microbial community in the HCs group remained relatively stable throughout the pregnancy, while the microbial structure alteration occurred in the GDM group during T2. A model based on ten bacteria and ten metabolites simultaneously was used to predict the risk of GDM developing in the pre-pregnancy state with the ROC value of 0.712. Algorithms on the basis of marker species and biochemical parameters can be used as effective tools for GDM risk evaluation before pregnancy.

Xylo-oligosaccharides enhance intestinal and thymic immunity by modulating pyroptosis, gut microbiota, and Th17/Treg immune response in lipopolysaccharide-challenged piglets

Xylo-oligosaccharides (XOS) have been shown to improve the immune system of weaned piglets, but the molecular mechanism of their action remains unclear. Therefore, this study aimed to investigate the impact of XOS on intestinal and thymic immune function in weaned piglets challenged with lipopolysaccharide (LPS) and elucidate the underlying mechanism. In a 2 × 2 factorial arrangement, consisting of diet treatment (basal diet vs 0.02% XOS diet) and immunological challenge [saline vs LPS], 24 piglets were randomly divided into 4 groups (n = 6): CON group, basal diet + saline; LPS group, basal diet + LPS; XOS group, 0.02% XOS diet + saline; XOS_LPS group, 0.02% XOS diet + LPS. Piglets were fed either the basal or XOS diet for 21 d, followed by intraperitoneal injections of normal saline or LPS on the 22nd day. Ileum, thymus, and colon samples were collected 4 h after the intraperitoneal saline or LPS injection. The piglets fed the XOS diet had higher average daily feed intake and average daily weight gain (P < 0.05). The XOS diet increased ileal villus height and decreased crypt depth. XOS also enhanced ileal and thymic antioxidant enzyme activities, anti-inflammatory cytokine expression, and decreased malondialdehyde levels and mRNA abundance of pro-inflammatory cytokines in piglets (P < 0.05). The XOS diet also downregulated the ileal and thymic NOD-like receptor family pyrin domain containing 3 and gasdermin-D gene and protein expression associated with pyroptosis (P < 0.05). Moreover, The XOS diet increased the mRNA abundance of forkhead box P3, signal transducer and activator of transcription 5, and transforming growth factor beta 1 while decreasing signal transducer and activator of transcription 3 and retinoid-related orphan receptor-gammat mRNA abundance (P < 0.05). The XOS diet enhanced forkhead box P3 protein expression and reduced retinoid-related orphan receptor-gammat protein expression following the LPS challenge (P < 0.05). At the same time, The XOS diet affected the gut microbiota and increased levels of short-chain fatty acids (P < 0.05). In conclusion, XOS may modulate ileal and thymic immune function in weaned piglets following a 4-h LPS challenge by affecting gut microbiota, pyroptosis, and Th17/Treg immune responses.

Polymerization of dietary fructans differentially affects interactions among intestinal microbiota of colitis mice

The intestinal microbiota plays a critical role in maintaining human health and can be modulated by dietary interventions and lifestyle choices. Fructans, a dietary carbohydrate, are selectively utilized by the intestinal microbiota to confer health benefits. However, the specific effects of different fructan types on microbial changes and functions remain incompletely understood. Here, we investigated how the intestinal microbiota responds to fructans with varying degrees of polymerization in the context of gut dysbiosis. Both low molecular weight fructo-oligosaccharides and high molecular weight levan suppressed intestinal inflammation in a colitis mouse model, mitigating intestinal fibrosis and dysbiosis. Although both the effects of fructo-oligosaccharides and levan are microbiota-dependent, distinct modulation patterns of the intestinal microbiota were observed based on the molecular weight of the fructans. Levan had a more pronounced and persistent impact on gut microbiota compared to fructo-oligosaccharides. Levan particularly promoted the abundance of Dubosiella newyorkensis, which exhibited preventive effects against colitis. Our findings highlight the importance of polymerization levels of dietary fructans in microbiota alterations and identify Dubosiella newyorkensis as a potential probiotic for treating inflammatory diseases.

High-fat/high-sucrose diet results in a high rate of MASH with HCC in a mouse model of human-like bile acid composition

BACKGROUND

Wild-type (WT) mice fed a conventional high-fat/high-sucrose diet (HFHSD) rarely develop metabolic dysfunction-associated steatohepatitis (MASH) with HCC. Because mouse bile acid (BA) is highly hydrophilic, we hypothesized that making it hydrophobic would lead to MASH with HCC.

METHODS

Eleven-week-old WT and Cyp2a12/Cyp2c70 double knockout (DKO) mice were divided into two groups, including one which was fed a normal chow diet, and one which was fed an HFHSD. Samples were collected after 15, 30, 47, and 58 weeks for histological, biochemical, and immunological analyses.

RESULTS

In the HFHSD group, body weight gain did not differ in WT versus DKO mice, although HFHSD-fed DKO mice exhibited markedly accelerated liver inflammation, fibrosis, and carcinogenesis. HFHSD upregulated lipogenesis and downregulated fatty acid oxidation in both WT and DKO mice, which increased liver lipid accumulation and lipotoxicity. However, the increase in reactive oxygen species production and carcinogenesis observed in DKO mice could not be explained by abnormal lipid metabolism alone. Regarding BA metabolism, DKO mice had a higher hydrophobicity index. They exhibited an age-associated increase in chenodeoxycholic acid (CDCA) levels because of CYP8B1 activity inhibition due to the farnesoid X receptor activation. HFHSD further downregulated CYP8B1, presumably by activating the Liver X receptor. Liver CDCA accumulation was associated with increased inflammation, reactive oxygen species production, and hepatocyte FGF15 induction. Moreover, in noncancerous liver tissues, HFHSD appeared to activate STAT3, an oncogenic transcription factor, which was enhanced by a CDCA-rich environment.

CONCLUSIONS

Here, we developed a new model of MASH with HCC using mice with human-like BA composition and found that HFHSD and elevated hepatic CDCA synergistically increased the risk of MASH with HCC.

Unveiling the role of Pafah1b3 in liver fibrosis: A novel mechanism revealed

Liver fibrosis is a common outcome of various chronic hepatic insults, characterized by excessive extracellular matrix (ECM) deposition. The precise mechanisms, however, remain largely undefined. This study identified an elevated expression of platelet-activating factor acetylhydrolase 1B3 (Pafah1b3) in liver tissues from both carbon tetrachloride (CCl4)-treated mice and patients with cirrhosis. Deletion of Pafah1b3 significantly attenuated CCl4-induced fibrosis, hepatic stellate cell (HSC) activation, and activation of transforming growth factor-β (TGF-β) signaling. Mechanistically, PAFAH1B3 binds to mothers against decapentaplegic homolog 7 (SMAD7), disrupting SMAD7's interaction with TGF-β receptor 1 (TβR1), which subsequently decreases TβR1 ubiquitination and degradation. Pharmacological inhibition using 3-IN-P11, a specific Pafah1b3 inhibitor, conferred protective effects against CCl4-induced fibrosis in mice. Furthermore, Pafah1b3 deficiency reduced hepatic inflammation. Overall, these results establish a pivotal role for Pafah1b3 in modulating TGF-β signaling and driving HSC activation.

Dietary Influences on Gut Microbiota and Their Role in Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a major contributor to liver-related morbidity, cardiovascular disease, and metabolic complications. Lifestyle interventions, including diet and exercise, are first line in treating MASLD. Dietary approaches such as the low-glycemic-index Mediterranean diet, the ketogenic diet, intermittent fasting, and high fiber diets have demonstrated potential in addressing the metabolic dysfunction underlying this condition. The development and progression of MASLD are closely associated with taxonomic shifts in gut microbial communities, a relationship well-documented in the literature. Given the importance of diet as a primary treatment for MASLD, it is important to understand how gut microbiota and their metabolic byproducts mediate favorable outcomes induced by healthy dietary patterns. Conversely, microbiota changes conferred by unhealthy dietary patterns such as the Western diet may induce dysbiosis and influence steatotic liver disease through promoting hepatic inflammation, up-regulating lipogenesis, dysregulating bile acid metabolism, increasing insulin resistance, and causing oxidative damage in hepatocytes. Although emerging evidence has identified links between diet, microbiota, and development of MASLD, significant gaps remain in understanding specific microbial roles, metabolite pathways, host interactions, and causal relationships. Therefore, this review aims to provide mechanistic insights into the role of microbiota-mediated processes through the analysis of both healthy and unhealthy dietary patterns and their contribution to MASLD pathophysiology. By better elucidating the interplay between dietary nutrients, microbiota-mediated processes, and the onset and progression of steatotic liver disease, this work aims to identify new opportunities for targeted dietary interventions to treat MASLD efficiently.

Taurochenodeoxycholic acid ameliorates the Staphylococcus aureus infection-induced acute lung injury through toll-like receptor 2 in mice

Acute lung injury (ALI) is a significant clinical problem associated with high morbidity and mortality. Inflammation induced by gram-positive bacterial pathogens, specifically Staphylococcus aureus (S. aureus), plays a major role in ALI development and other infectious diseases. Taurochenodeoxycholic acid (TCDCA) exhibits diverse biological activities and pharmacological effects. Nevertheless, the potential preventive and therapeutic effects of TCDCA and the underlying mechanism in the ALI induced by S. aureus infection remain poorly understood. Our results showed that the TCDCA (0.1 μg/g) had a beneficial effect on lung damage in mice infected with S. aureus. Specifically, TCDCA could lead to a reduction in pulmonary focal or diffuse oedema and a decrease in the infiltration of neutrophils in the S. aureus-infected lungs. We observed that TCDCA could significantly down-regulate the expression of HMGB1 in lung from S. aureus-infected mice. Furthermore, TCDCA could attenuate the production of inflammatory mediators in lungs and serum from S. aureus-infected mice. This finding further supported the notion that TCDCA potentially protects against tissue injury. In addition, TCDCA regulated the secretion of the proinflammatory cytokine, the activation of MAPK and NF-κB signaling pathways, and the activation of TLR2 in macrophages. Notably, TCDCA might reduce the secretion levels of inflammatory mediators and lung damage through the TLR2 in S. aureus-infected macrophages or mice. Altogether, TCDCA shows promise as a potential drug for preventing and treating ALI by modulating or inhibiting inflammatory mediators through TLR2.

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.

Therapeutic potential of Parabacteroides distasonis in gastrointestinal and hepatic disease

Increasing evidences indicate that the gut microbiota is involved in the development and therapy of gastrointestinal and hepatic disease. Imbalance of gut microbiota occurs in the early stages of diseases, and maintaining the balance of the gut microbiota provides a new strategy for the treatment of diseases. It has been reported that Parabacteroides distasonis is associated with multiple diseases. As the next-generation probiotics, several studies have demonstrated its positive regulation on the gastrointestinal and hepatic disease, including inflammatory bowel disease, colorectal cancer, hepatic fibrosis, and fatty liver. The function of P. distasonis and its metabolites mainly affect host immune system, intestinal barrier function, and metabolic networks. Manipulation of P. distasonis with natural components lead to the protective effect on enterohepatic disease. In this review, the metabolic pathways regulated by P. distasonis are summarized to illustrate its active metabolites and their impact on host metabolism, the role and action mechanism in gastrointestinal and hepatic disease are discussed. More importantly, the natural components can be used to manipulate P. distasonis as treatment strategies, and the challenges and perspectives of P. distasonis in clinical applications are discussed.

Neuroprotection of celastrol against postoperative cognitive dysfunction through dampening cGAS-STING signaling

Neuroinflammation is a central player in postoperative cognitive dysfunction (POCD), an intractable and highly confounding neurological complication with finite therapeutic options. Celastrol, a quinone methide triterpenoid, is a bioactive ingredient extracted from Tripterygium wilfordii with talented anti-inflammatory capacity. However, it is unclear whether celastrol can prevent anesthesia/surgery-evoked cognitive deficits in an inflammation-specific manner. The STING agonist 5,6-dimethylxanthenone-4-acetic acid (DMXAA) was used to determine whether celastrol possesses neuroprotection dependent on the STING pathway in vivo and in vitro. Isoflurane and laparotomy triggered cGAS-STING activation, caspase-3/GSDME-dependent pyroptosis, and enhanced Iba-1 immunoreactivity. Celastrol improved cognitive performance and decreased the levels of cGAS, 2'3'-cGAMP, STING, NF-κB phosphorylation, Iba-1, TNF-α, IL-6, and IFN-β. Downregulation of cleaved caspase-3 and N-GSDME was observed in the hippocampus of POCD mice and HT22 cells after celastrol administration, accompanied by limited secretion of pyroptosis-pertinent pro-inflammatory cytokines IL-1β and IL-18. DMXAA neutralized the favorable influences of celastrol on cognitive function, as confirmed by the activation of the STING/caspase-3/GSDME axis. These findings implicate celastrol as a therapeutic agent for POCD through anti-inflammation and anti-pyroptosis.

Gut microbiota in health and disease: advances and future prospects

The gut microbiota plays a critical role in maintaining human health, influencing a wide range of physiological processes, including immune regulation, metabolism, and neurological function. Recent studies have shown that imbalances in gut microbiota composition can contribute to the onset and progression of various diseases, such as metabolic disorders (e.g., obesity and diabetes) and neurodegenerative conditions (e.g., Alzheimer's and Parkinson's). These conditions are often accompanied by chronic inflammation and dysregulated immune responses, which are closely linked to specific forms of cell death, including pyroptosis and ferroptosis. Pathogenic bacteria in the gut can trigger these cell death pathways through toxin release, while probiotics have been found to mitigate these effects by modulating immune responses. Despite these insights, the precise mechanisms through which the gut microbiota influences these diseases remain insufficiently understood. This review consolidates recent findings on the impact of gut microbiota in these immune-mediated and inflammation-associated conditions. It also identifies gaps in current research and explores the potential of advanced technologies, such as organ-on-chip models and the microbiome-gut-organ axis, for deepening our understanding. Emerging tools, including single-bacterium omics and spatial metabolomics, are discussed for their promise in elucidating the microbiota's role in disease development.

Dynamic Shifts in Antibiotic Residues and Gut Microbiome Following Tilmicosin Administration to Silkie Chickens

Tilmicosin, an antibiotic widely used in animal husbandry to prevent and treat bacterial infections, raises concerns due to its residual accumulation, which impacts both animal health and food safety. In this study, we conducted a comprehensive analysis of tilmicosin clearance patterns in different tissues, assessed physiological impacts through blood biochemistry, and investigated changes in gut microbial composition with 16S rRNA sequencing of the tilmicosin-treated Silkie chickens. Initially, we observed rapid peaks in tilmicosin residues in all tissues within 1 day after treatment, but complete metabolism took longer, extending beyond 9 days. Moreover, tilmicosin treatment significantly decreased serum levels of total bile acid, blood urea nitrogen, and uric acid, while increasing the levels of direct bilirubin, total bilirubin, and glutathione peroxidase at day 3, followed by a decrease from day 5 onwards. The effects of tilmicosin use on microbial composition and diversity lasted for an extended period, with the relative abundance of Proteobacteria remaining significantly different between the control and tilmicosin-treated groups at 120 days. Additionally, correlation analysis revealed a strong positive correlation between Mucispirillum_schaedleri and tilmicosin residue in all tissues, while Parabbacteroide_distasonis, Faecalibacterium_prausnitzii, and others exhibited negative correlations with tilmicosin residue. Overall, our study indicates a significant correlation between intestinal microbes and antibiotic residues, providing a theoretical basis for guiding the withdrawal period after antibiotic use.

Ampelopsis grossedentata tea alleviating liver fibrosis in BDL-induced mice via gut microbiota and metabolite modulation

Liver fibrosis (LF) is a common sequela to diverse chronic liver injuries, leading to rising rates of cirrhosis and hepatocellular carcinoma (HCC). As the medicinal and edible homologous material, traditional teas have exhibited promising applications in the clinical management of liver fibrosis. Here, we generated a liver fibrosis mouse model to explore the potent therapeutic ability of Ampelopsis grossedentata (AG) tea on this condition by multi-omics analysis. The biochemistry results pointed towards mitigated increases of ALT, AST, TBIL, and ALP triggered by BDL in the AG-treated group. Examination using H&E and Sirius Red staining revealed severe liver injuries, inflammation infiltration, amplified fibrosed regions, and the creation of bile ducts, all of which were fallout from BDL. Immunohistochemistry findings also implicated a noteworthy upregulation of the HSC activation marker α-smooth muscle actin (α-SMA) and the fibrosis marker collagen I in the BDL group. However, these symptoms demonstrated a significant improvement in the group treated with 100 mg/kg AG. Findings from the Western Blot test corroborated the prominent elevation of TNF-α, col1a1, α-SMA, and TGF-β, instigated by BDL, while AG treatment meaningfully modulated these proteins. Furthermore, our study underscored the potential involvement of several microbiota, such as Ruminococcaceae UCG-014, Eubacterium Ruminantium, Ruminococcus 1, Christensenellaceae R-7, Acetatifactor, Dubosiella, Parasutterella, Faecalibaculum, and Defluviitaleaceae UCG-011, in the progression of liver fibrosis and the therapeutic efficacy of AG. This investigation shows that during the process of AG ameliorating BDL-induced liver fibrosis, bile acid derivatives such as CDCA, TCDCA, 3-DHC, UCA, DCA, among others, play significant roles. In this study, we identified that several non-bile acid metabolites, such as Deltarasin, Thr-Ile-Arg, etc., are entailed in the process of AG improving liver fibrosis.

Gut commensal Parabacteroides distasonis exerts neuroprotective effects in acute ischemic stroke with hyperuricemia via regulating gut microbiota-gut-brain axis

BACKGROUND

Hyperuricemia is considered as an independent risk factor for acute ischemic stroke (AIS), and some AIS patients are accompanied by an increase in serum uric acid. Recent studies have highlighted the important role of gut microbiota in both hyperuricemia and AIS, but there is little available data on the relationship between gut microbiota and the pathogenesis of AIS with hyperuricemia (HAS).

METHODS

Here we profiled the gut microbiota composition in 63 HAS patients and 269 non-HAS patients through 16s rRNA sequencing. Male rat with hyperuricemia were subjected to middle cerebral artery occlusion (MCAO) to establish HAS model and were then treated with Parabacteroides distasonis. Subsequently, the neurological deficit, pathological damages and blood-brain barrier disruption were evaluated. Moreover, the levels of ROS, inflammatory cytokines, NF-𝜿B pathway related protein, and vascular density markers were determined.

RESULTS

There were significant differences of gut microbiota composition between HAS patients and non-HAS patients, and a significant decrease in the abundance of Parabacteroides in HAS patients compared to non-HAS patients. Animal experiments showed that supplementation with P. distasonis increased beneficial commensal bacteria, significantly improved neurological deficits, pathological damages and BBB disruption, as well as reduced the level of serum uric acid in HAS rats. We further demonstrated that P. distasonis treatment decreased ROS level and increased SOD2 level, thereby reducing oxidative stress. Meanwhile, P. distasonis effectively inhibited NF-𝜿B signal pathway and reduced the production of inflammatory cytokines, including TNF-α and IL-1β, alleviating the inflammatory response. Notably, P. distasonis treatment increased the levels of vascular density markers including cluster of differentiation 31 (CD31) and alpha-smooth muscle actin (α-SMA), ameliorating vascular damage in HAS rats.

CONCLUSIONS

Together, these findings highlighted the important role of P. distasonis in the pathogenesis of HAS, and its mechanism was involved in the regulation of gut microbiota-gut-brain axis, which implied a novel strategy against HAS.

Fucoidan ameliorates alcohol-induced liver injury in mice through Parabacteroides distasonis-mediated regulation of the gut-liver axis

Polysaccharides can benefit the liver via modulation of the gut microbiota, but the exact mechanism is still unclear. This study demonstrated that the effect of Scytosiphon lomentaria fucoidan (SLF) on alcohol-induced liver injury can be closely related to the level of Parabacteroides distasonis (Pd) via in vivo and in vitro models. Further mice experiment showed that Pd alleviated liver injury and inflammation by suppressing the NF-κB/MAPK pathways and activating Nrf2 pathway. The underlying mechanism can be closely associated with modulation of the gut microbiota, particularly an increase in microbiota diversity and beneficial bacteria and a reduction in Proteobacteria. Targeted metabolomics indicated that Pd ameliorated alcohol-induced dysbiosis of microbiota metabolites profile, primarily affecting amino acid metabolism. Moreover, Pd reduced the level of total bile acids (BAs) and improved BAs profile, affecting the expression levels of BA-associated genes in the liver and ileum involved in BA synthesis, transport, and reabsorption. This study suggests that SLF can benefit alcohol-induced liver injury via P. distasonis-mediated regulation of the gut-liver axis.

Sulforaphane Improves Liver Metabolism and Gut Microbiota in Circadian Rhythm Disorder Mice Models Fed With High-Fat Diets

SCOPE

This study aims to investigate the effect of sulforaphane (SFN) on hepatic metabolism and gut microbiota in a shifted circadian rhythm (CR) mouse model fed with a high-fat diet (HFD).

METHODS AND RESULTS

A shifted CR mouse model with HFD is constructed. Biochemical analyses are used to evaluate the effects of SFN on lipid accumulation and liver function. Targeted metabolomics is used for liver metabolites. Results from hematoxylin and eosin staining and Oil Red O staining show that SFN improves liver lipid accumulation and intestinal inflammatory damage in shifted CR treatment with HFD. The concentrations of amino acid metabolites are increased, and the levels of bile acid metabolites are significantly decreased by SFN treatment. Results from 16S rRNA gene sequencing indicate that SFN modulates gut microbiota, particularly by enhancing beneficial bacteria such as Lachnospiraceae, Lactobacillus, Alistipes, Akkermansia, and Eubacteriaum coprostanoligenes. Correlation analysis confirms a close relationship between intestinal microbiota and hepatic metabolites. SFN significantly regulates CR protein expression in the hypothalamus and liver tissues.

CONCLUSION

SFN alleviates hepatic metabolic disorder and gut microbiota dysbiosis induced by CR disruption under a high-fat diet in a mouse model, indicating the potential of SFN in regulating CR disruption.

Mass spectrometry-based metabolomics reveals metabolism of molnupiravir may lead to metabolic disorders and hepatotoxicity

Molnupiravir (MO) is a pyrimidine nucleoside anti-SARS-CoV-2 drug. MO treatment could cause mild liver injury. However, the underlying mechanism of MO-induced liver injury and the metabolic pathway of MO in vivo are unclear. In this study, metabolomics analysis and molecular biology methods were used to explore these issues. Through metabolomics analysis, it was found that the homeostasis of pyrimidine, purine, lysophosphatidylcholine (LPC), and amino acids in mice was destroyed after MO treatment. A total of 80 changed metabolites were detected. Among these changed metabolites, 4-ethylphenyl sulfate, dihydrouracil, and LPC 20:0 was related to the elevation of alkaline phosphatase (ALP), interleukin-6 (IL6), and nuclear factor kappa-B (NF-κB). The levels of 4-ethylphenyl sulfate, dihydrouracil, and LPC 20:0 in plasma were positively correlated with their levels in the liver, suggesting that these metabolites were associated with MO-induced liver injury. MO treatment could increase NHC and cytidine levels, activate cytidine deaminase (CDA), and increase LPC levels. CDA and LPC could increase the mRNA expression level of toll-like receptor (TLR). The current study indicated that the elevation of hepatic TLR may be an important reason for MO leading to the liver injury.

Gut microbiota depletion and FXR inhibition exacerbates zonal hepatotoxicity of sunitinib

Rationale: Sunitinib is a small-molecule tyrosine kinase inhibitor associated with the side-effect of liver injury. The impaired cell type in liver and the hepatotoxicity mechanisms is still unclear. Methods: Spatial metabolomics, transmission electron microscopy, immunofluorescence co-staining, and isolation of bile duct cells and liver sinusoidal endothelial cells (LSECs) were used to evaluate the zonated hepatotoxicity of sunitinib. Farnesoid X receptor (FXR) conditional knockout mice, metagenomics analysis, bacteria clearance, bacterial culture, Parabacteroides distasonis and 3-oxolithocholic acid supplementation were used to evaluate the hepatotoxicity mechanisms of sunitinib. Results: Phenotype analysis found that hepatic autophagy, apoptosis, and mitochondrial injury were observed in vivo or in vitro after sunitinib treatment. By using spatial metabolomics and isolation of bile duct cells and LSECs, the zonated drug toxicity was observed around the portal vein. Hepatocytes, bile duct cells, and LSECs were damaged after sunitinib treatment. FXR inhibition and gut microbiota depletion aggravated sunitinib-induced liver injury. For diurnal variation, sunitinib-induced liver injury was enhanced at night compared with that at day, and FXR and gut microbiota participated in circadian rhythmic hepatotoxicity induced by sunitinib. Conclusions: Our data suggested activation of FXR and Parabacteroides distasonis supplementation may be used to improve sunitinib-induced hepatotoxicity.

Low molecular fucoidan alleviated alcohol-induced liver injury in BALB/c mice by regulating the gut microbiota-bile acid-liver axis

Fucoidan has attracted significant attention owing to its remarkable bioactivities, but the effect of molecular weight (Mw) on its activities in the context of alcoholic liver diseases (ALD) is poorly understood. In this study, low Mw fucoidan (OSLF) was prepared, and its protective effect against alcohol-induced liver injury was assessed in a mouse model. OSLF increased weight gain and colon length, improved lipid disorders, and reduced oxidative stress in mice exposed to alcohol, alleviating liver injury. OSLF alleviated inflammation in the liver by inhibiting alcohol-activated NF-κB and MAPK pathways. The underlying mechanism can be attributed to the improvement of alcohol-induced dysbiosis of the gut microbiota, including a decrease in Proteobacteria and Bacteroidetes and an increase in microbiota diversity, as well as the abundances of Parabacteroides, Bacteroides, and Faecalibaculum. Metabolomics results showed that OSLF improved alcohol-induced abnormalities of microbiota metabolites, primarily involving amino acid metabolism and short chain fatty acids production. In addition, OSLF ameliorated bile acid metabolism in the gut and regulated the expression of bile acid-associated genes in the liver, affecting bile acid synthesis, regulation, and transport. It suggested that OSLF had the potential for the management of ALD by regulating the gut microbiota-bile acid-liver axis.

Palmitoleic Acid Inhibits Hepatotoxic Effects by Reducing Trimethylamine-N-Oxide (TMAO) Formation in High L-Carnitine-Treated Mice

BACKGROUND/OBJECTIVES

This study investigated the effects of palmitoleic acid (POA) consumption on liver function, intestinal microbiota, and trimethylamine-N-oxide (TMAO) levels in the serum of mice treated with 3% L-carnitine drinking water. The purpose was to highlight the impact of POA on liver injury associated with high L-carnitine intake.

METHODS

A correlation analysis was carried out. The physiological and biochemical results showed that the administration of POA could alleviate liver injury induced by high L-carnitine ingestion, as reflected by a reduction in liver function indices (ALT, AST, AKP, and TBA activities) and modulation of antioxidant enzyme activities (SOD, GSH-Px, MDA, and RAHFR). The study also monitored the levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C). Additionally, to assess the impact of POA on intestinal microbiota, we conducted a 16S rRNA high-throughput sequencing analysis.

RESULTS

The findings indicated that POA administration resulted in lower levels of TMAO in treated mice. Furthermore, POA could regulate the composition of intestinal microbiota in L-carnitine mice, particularly affecting Bacteroides vulgatus, Parabacteroides distasonis, Alistipes shahii, Lachnospiraceae NK4A136 group, and Parasutterella secunda, which were closely related to liver injury.

CONCLUSIONS

In summary, POA could repair liver damage caused by high intake of L-carnitine by regulating the distribution of intestinal flora and subsequently decreasing serum TMAO levels.

The Role of Mitochondrial Permeability Transition in Bone Metabolism, Bone Healing, and Bone Diseases

Bone is a dynamic organ with an active metabolism and high sensitivity to mitochondrial dysfunction. The mitochondrial permeability transition pore (mPTP) is a low-selectivity channel situated in the inner mitochondrial membrane (IMM), permitting the exchange of molecules of up to 1.5 kDa in and out of the IMM. Recent studies have highlighted the critical role of the mPTP in bone tissue, but there is currently a lack of reviews concerning this topic. This review discusses the structure and function of the mPTP and its impact on bone-related cells and bone-related pathological states. The mPTP activity is reduced during the osteogenic differentiation of mesenchymal stem cells (MSCs), while its desensitisation may underlie the mechanism of enhanced resistance to apoptosis in neoplastic osteoblastic cells. mPTP over-opening triggers mitochondrial swelling, regulated cell death, and inflammatory response. In particular, mPTP over-opening is involved in dexamethasone-induced osteoblast dysfunction and bisphosphonate-induced osteoclast apoptosis. In vivo, the mPTP plays a significant role in maintaining bone homeostasis, with many bone disorders linked to its excessive opening. Genetic deletion or pharmacological inhibition of the over-opening of mPTP has shown potential in enhancing bone injury recovery and alleviating bone diseases. Here, we review the findings on the relationship of the mPTP and bone at both the cellular and disease levels, highlighting novel avenues for pharmacological approaches targeting mitochondrial function to promote bone healing and manage bone-related disorders.

Ursolic Acid Regulates Immune Balance, Modulates Gut Microbial Metabolism, and Improves Liver Health in Mice

Ursolic acid (UA) has demonstrated significant immunomodulatory and hepatoprotective effects; however, the underlying mechanisms remain unclear. This study aims to analyze the impact of UA on the gut microbiome, metabolome, and liver transcriptome, investigate UA's role in maintaining gut immune homeostasis and liver health, and evaluate the potential contributions of gut microbes and their metabolites to these beneficial effects. Our findings indicate that UA enhances immune balance in the jejunum, fortifies intestinal barrier function, and promotes overall gut health. UA modulates the intestinal microbiota and its metabolic processes, notably increasing the abundance of beneficial bacteria such as Odoribacter and Parabacteroides, along with their metabolites, including ornithine and lactucin. Additionally, UA inhibits the expression of interleukin-1 receptor 1 (IL1R1) and calcium (Ca2+) voltage-gated channel auxiliary subunit beta 2 (CACNB2) while enhancing the synthesis pathways of retinol and ascorbic acid, thereby exerting a protective influence on liver function. In summary, UA enhances intestinal immune homeostasis and promotes liver health, with these advantageous effects potentially mediated by beneficial bacteria (Odoribacter and Parabacteroides) and their metabolites (ornithine and lactucin).

Effect of Ilex hainanensis Merr. On HFD-induced nonalcoholic fatty liver disease and rebalance of gut microbiota and bile acids metabolism in mice

Nonalcoholic fatty liver disease (NAFLD) is a clinicopathological syndrome characterized by excessive intracellular fat deposition in the hepatocytes, and the development is exacerbated by gut microbiota and bile acids metabolism disorders. Ilex hainanensis Merr. is a traditional medicine of the Zhuang nationality, historically esteemed for its efficacy in lowering blood pressure and lipid levels. This study aimed to investigate the pharmacodynamic effects in NAFLD mice and impacts on gut microbiota and bile acids (BAs) metabolism of I. hainanensis extract (IHA). 16 compounds were identified from IHA by HPLC-DAD-MS analysis. IHA significantly reduced body weight indexs, alanine transaminase (ALT) and aspartate transaminase (AST) activities, improved dyslipidemia and insulin resistance (IR), and effectively ameliorated hepatic steatosis in HFD-induced NAFLD mice. IHA also altered gut microbiota composition, particularly enhancing the abundance of bacteria involved in BAs metabolism, as well as augmented BAs synthesis in the liver and increased fecal excretion. In conclusion, our findings suggest that IHA holds promise in improving NAFLD conditions and modulating gut microbiota and BAs metabolism. These insights contribute to a deeper understanding of the mechanisms underlying IHA-mediated alleviation of lipid accumulation in NAFLD.

Pyroptosis in health and disease: mechanisms, regulation and clinical perspective

Pyroptosis is a type of programmed cell death characterized by cell swelling and osmotic lysis, resulting in cytomembrane rupture and release of immunostimulatory components, which play a role in several pathological processes. Significant cellular responses to various stimuli involve the formation of inflammasomes, maturation of inflammatory caspases, and caspase-mediated cleavage of gasdermin. The function of pyroptosis in disease is complex but not a simple angelic or demonic role. While inflammatory diseases such as sepsis are associated with uncontrollable pyroptosis, the potent immune response induced by pyroptosis can be exploited as a therapeutic target for anti-tumor therapy. Thus, a comprehensive review of the role of pyroptosis in disease is crucial for further research and clinical translation from bench to bedside. In this review, we summarize the recent advancements in understanding the role of pyroptosis in disease, covering the related development history, molecular mechanisms including canonical, non-canonical, caspase 3/8, and granzyme-mediated pathways, and its regulatory function in health and multiple diseases. Moreover, this review also provides updates on promising therapeutic strategies by applying novel small molecule inhibitors and traditional medicines to regulate pyroptosis. The present dilemmas and future directions in the landscape of pyroptosis are also discussed from a clinical perspective, providing clues for scientists to develop novel drugs targeting pyroptosis.

Infection‑associated bile acid disturbance contributes to macrophage activation in patients with cirrhosis

Cirrhosis impairs macrophage function and disrupts bile acid homeostasis. Although bile acids affect macrophage function in patients with sepsis, whether and how the bile acid profile is changed by infection in patients with cirrhosis to modulate macrophage function remains unclear. The present study aimed to investigate the changes in the bile acid profile of patients with cirrhosis and infection and their effects on macrophage function. Serum was collected from 20 healthy subjects, 18 patients with cirrhosis and 39 patients with cirrhosis and infection. Bile acid profiles were detected using high‑performance liquid chromatography‑triple time‑of‑flight mass spectrometer. The association between bile acid changes and infection was analysed using receiver operating characteristic (ROC) curves. Infection‑altered bile acids were used in combination with lipopolysaccharides (LPS) to stimulate RAW264.7/THP‑1 cells in vitro. The migratory capacity was evaluated using wound healing and Transwell migration assays. The expression of Arg‑1, iNOS, IκBα, phosphorylated (p‑)IκBα and p65 was examined with western blotting and immunofluorescence, Tnfα, Il1b and Il6 mRNA was examined with RT‑qPCR, and CD86, CD163 and phagocytosis was measured with flow cytometry. The ROC curves showed that decreased hyodeoxycholic acid (HDCA) and deoxycholic acid (DCA) levels were associated with infection. HDCA or DCA combined with LPS enhanced the phagocytic and migratory ability of macrophages, accompanied by upregulation of iNOS and CD86 protein expression as well as Tnfα, Il1b, and Il6 mRNA expression. However, neither HDCA nor DCA alone showed an effect on these phenotypes. In addition, DCA and HDCA acted synergistically with LPS to increase the expression of p‑IκBα and the intranuclear migration of p65. Infection changed the bile acid profile in patients with cirrhosis, among which the reduction of DCA and HDCA associated most strongly with infection. HDCA and DCA enhanced the sensitivity of macrophage function loss to LPS stimulation. These findings suggested a potential role for monitoring the bile acid profile that could help manage patients with cirrhosis and infection.

Forsythiaside-A improved bile-duct-ligation-induced liver fibrosis in mice: The involvement of alleviating mitochondrial damage and ferroptosis in hepatocytes via activating Nrf2

Liver fibrosis is a key and reversible stage in the progression of many chronic liver diseases to cirrhosis or hepatocellular carcinoma. Forsythiaside-A (FTA), a main compound isolated from Forsythiae Fructus, has an excellent liver protective activity. This study aims to investigate the efficacy of FTA in improving cholestatic liver fibrosis. Bile-duct-ligation (BDL) was conducted to induce liver fibrosis in mice. Hepatic collagen deposition was evaluated by Masson and Sirus red staining. The bile acid spectrum in the liver and serum was analyzed by mass spectrometry. Liver oxidative stress injury and mitochondria damage were observed by using Mito-Tracker Red fluorescence staining, transmission electron microscopy, etc. The level of ferrous iron (Fe2+) and the expression of ferroptosis-associated molecules were detected. The binding between FTA and its target protein was confirmed by Co-immunoprecipitation (Co-IP), cellular thermal shift assay (CETSA), drug affinity responsive target stability (DARTS) and surface plasmon resonance (SPR). Our results demonstrated that FTA alleviated BDL-induced liver fibrosis in mice. FTA did not decrease the elevated amount of bile acids in BDL-treated mice, but reduced the bile acid-induced mitochondrial damage, oxidative stress and ferroptosis in hepatocytes, and also induced nuclear factor erythroid 2-related factor-2 (Nrf2) activation. In Nrf2 knock-out mice, the FTA-provided protection against BDL-induced liver fibrosis was disappeared, and FTA's inhibition on mitochondrial damage, oxidative stress and ferroptosis were lowered. Further results displayed that FTA could directly bind to Kelch-like ECH-associated protein-1 (Keap1), thereby activating Nrf2. Moreover, the BDL-induced liver fibrosis was markedly weakened in liver-specific Keap1 knockout mice. Hence, this study suggests that FTA alleviated the BDL-induced liver fibrosis through attenuating mitochondrial damage and ferroptosis in hepatocytes by activating Nrf2 via directly binding to Keap1.

Coordinated elimination of bacterial taxa optimally attenuates alloimmunity and prolongs allograft survival

This study aimed to dissect the relationship between specific gut commensal bacterial subgroups, their functional metabolic pathways, and their impact on skin allograft outcome and alloimmunity. We previously showed that oral broad-spectrum antibiotic (Abx) pretreatment in mice delayed skin, heart, and lung allograft rejection and dampened alloimmune responses. Here, rationally designed Abx combinations targeting major bacterial groups were used to elucidate their individual contribution to modulating alloimmune responses. Abx cocktails targeting intestinal gram-negative, gram-positive, or anaerobic/gram-positive bacteria by oral gavage, all delayed skin allograft rejection, and reduced alloreactive T cell priming to different extents. Notably, the most pronounced extension of skin allograft survival and attenuation of alloimmunity were achieved when all gut bacterial groups were simultaneously targeted. These results suggest a model in which the strength of the alloimmune response is additively tuned up by gut microbial diversity. Shotgun metagenomic sequencing enabled strain-level resolution and identified a shared commensal, Parabacteroides distasonis, as the most enriched following all Abx treatments. Oral administration of P.distasonis to mice harboring a diverse microbiota significantly prolonged skin allograft survival, identifying a probiotic with therapeutic benefit in transplantation.

Phenylethanol Glycoside from Cistanche tubulosa Attenuates BSA-Induced Liver Fibrosis in Rats by Modulating the Gut Microbiota-Liver Axis

This study aimed to investigate the effect of phenylethanol glycoside from Cistanche tubulosa (CPhGs) on the prevention of bovine serum albumin (BSA)-induced hepatic fibrosis in rats. Investigation of the mechanisms of the anti-hepatic fibrosis effect was focused on CPhGs' influence on the "gut-liver" regulation, including the gut microbiota, intestinal barrier, systemic lipopolysaccharide (LPS) concentration, and LPS-related signaling pathway. The results show that CPhGs restored the diversity of gut microbiota, increased the relative abundance of Bacteroidetes, and decreased the relative abundance of Firmicutes and Proteobacteria in the fibrotic rats. In addition, CPhGs promoted the enrichment of probiotics such as Blautia, Oscillospira, Ruminococcus, Odoribacter, Bacteroides, and Parabacteroides in intestines of these rats. Furthermore, CPhGs reduced histopathological injury in the intestine and restored the tight junctions of the intestine by increasing the expression of ZO-1, occludin, and E-cadherin. CPhGs efficiently reduced serum LPS and liver lipopolysaccharide-binding protein (LBP) levels and inhibited the LPS-TLR4/MyD88/NF-κB pathway, which is related to protein expression in the liver. Correlation analysis confirmed that these beneficial bacteria were negatively associated with pathological damage, while LPS and harmful bacteria were positively associated with liver injury. Our fecal microbiota transplantation (FMT) experiment confirmed that gut microbiota is an important part of disease progression and that CPhGs is useful for the prevention and treatment of hepatic fibrosis. Our data demonstrate that the anti-hepatic fibrosis mechanism of CPhGs was mediated by regulation of the "gut-liver" axis. These results can stimulate consideration for its use in clinical practices.

Celastrol-Ligustrazine compound proven to be a novel drug candidate for idiopathic pulmonary fibrosis by intervening in the TGF-β1 mediated pathways-an experimental in vitro and vivo study

Idiopathic Pulmonary Fibrosis (IPF) is a disease characterized by pulmonary interstitial fibrosis and collagen proliferation, currently lacking effective therapeutic options. The combined use of Celastrol and Ligustrazine has been proved to synergistically improve the pathological processes of inflammation and fibrosis. In earlier studies, we designed and synthesized a Celastrol-Ligustrazine compound CL-001, though its role in IPF remains unclear. Here, the effects and mechanisms of CL-001 in bleomycin (BLM)-induced IPF were investigated. In vivo, CL-001 significantly improved lung function, reduced pulmonary inflammation, and decreased collagen deposition, thereby preventing the progression of IPF. In vitro, CL-001 concurrently inhibited both Smad-dependent and Smad-independent pathways, thereby suppressing TGF-β1-induced epithelial-mesenchymal transition (EMT) and epithelial cell migration. This inhibitory effect was superior to that of Celastrol or Ligustrazine administered alone. Additionally, CL-001 significantly increased the level of apoptosis and promoted the expression of apoptosis-related proteins (Caspase-8 and PARP), ultimately leading to widespread apoptosis in activated lung epithelial cells. In summary, CL-001 exhibits excellent anti-IPF effects both in vitro and in vivo, suggesting its potential as a novel candidate drug for IPF, warranting further development.

Genetically predicted metabolites mediate the association between immune cells and metabolic dysfunction-associated steatotic liver disease: a mendelian randomization study

BACKGROUND

Existing studies have presented limited and disparate findings on the nexus between immune cells, plasma metabolites, and metabolic dysfunction-associated steatotic liver disease (MASLD). The aim of this study was to investigate the causal relationship between immune cells and MASLD. Additionally, we aimed to identify and quantify the potential mediating role of metabolites.

METHODS

A Mendelian randomization (MR) analysis was conducted using two samples of pooled data from genome-wide association studies on MASLD that included 2568 patients and 409,613 control individuals. Additionally, a mediated MR study was employed to quantify the metabolite-mediated immune cell effects on MASLD.

RESULTS

In this study, eight immunophenotypes were linked to the risk of MASLD, and thirty-five metabolites/metabolite ratios were linked to the occurrence of MASLD. Furthermore, a total of six combinations of immunophenotypic and metabolic factors demonstrated effects on the occurrence of MASLD, although the mediating effects of metabolites were not significant.

CONCLUSION

Our study demonstrated that certain immunophenotypes and metabolite/metabolite ratios have independent causal relationships with MASLD. Furthermore, we identified specific metabolites/metabolite ratios that are associated with an increased risk of MASLD. However, their mediating role in the causal association between immunophenotypes and MASLD was not significant. It is important to consider immune and metabolic disorders among patients with MASLD in clinical practice.

Research progress on the effect of pyroptosis on the occurrence, development, invasion and metastasis of colorectal cancer

Pyroptosis is a type of programmed cell death mediated by gasdermines (GSDMs). The N-terminal domain of GSDMs forms pores in the plasma membrane, causing cell membrane rupture and the release of cell contents, leading to an inflammatory response and mediating pyrodeath. Pyroptosis plays an important role in inflammatory diseases and malignant tumors. With the further study of pyroptosis, an increasing number of studies have shown that the pyroptosis pathway can regulate the tumor microenvironment and antitumor immunity of colorectal cancer and is closely related to the occurrence, development, treatment and prognosis of colorectal cancer. This review aimed to explore the molecular mechanism of pyroptosis and the role of pyroptosis in the occurrence, development, treatment and prognosis of colorectal cancer (CRC) and to provide ideas for the clinical diagnosis and treatment of CRC.

Dietary fiber alleviates alcoholic liver injury via Bacteroides acidifaciens and subsequent ammonia detoxification

The gut microbiota and diet-induced changes in microbiome composition have been linked to various liver diseases, although the specific microbes and mechanisms remain understudied. Alcohol-related liver disease (ALD) is one such disease with limited therapeutic options due to its complex pathogenesis. We demonstrate that a diet rich in soluble dietary fiber increases the abundance of Bacteroides acidifaciens (B. acidifaciens) and alleviates alcohol-induced liver injury in mice. B. acidifaciens treatment alone ameliorates liver injury through a bile salt hydrolase that generates unconjugated bile acids to activate intestinal farnesoid X receptor (FXR) and its downstream target, fibroblast growth factor-15 (FGF15). FGF15 promotes hepatocyte expression of ornithine aminotransferase (OAT), which facilitates the metabolism of accumulated ornithine in the liver into glutamate, thereby providing sufficient glutamate for ammonia detoxification via the glutamine synthesis pathway. Collectively, these findings uncover a potential therapeutic strategy for ALD involving dietary fiber supplementation and B. acidifaciens.

Astragalus polysaccharides-induced gut microbiota play a predominant role in enhancing of intestinal barrier function of broiler chickens

BACKGROUND

The intestinal barrier is the first line of defense against intestinal invasion by pathogens and foreign antigens and is closely associated with the gut microbiota. Astragalus polysaccharides (APS) have a long history of use in traditional Chinese medicine owing to its protective properties against intestinal barrier function. The mechanism of APS-induced gut microbiota enhancing intestinal barrier function is urgently needed.

RESULTS

Dietary polysaccharide deprivation induced intestinal barrier dysfunction, decreased growth performance, altered microbial composition (Faecalibacterium, Dorea, and Coprobacillus), and reduced isobutyrate concentration. The results showed that APS facilitates intestinal barrier function in broiler chickens, including a thicker mucus layer, reduced crypt depth, and the growth of tight junction proteins. We studied the landscape of APS-induced gut microbiota and found that APS selectively promoted the growth of Parabacteroides, a commensal bacterium that plays a predominant role in enhancing intestinal barrier function. An in vitro growth assay further verified that APS selectively increased the abundance of Parabacteroides distasonis and Bacteroides uniformis. Dietary APS supplementation increased the concentrations of isobutyrate and bile acid (mainly chenodeoxycholic acid and deoxycholate acid) and activated signaling pathways related to intestinal barrier function (such as protein processing in the endoplasmic reticulum, tight junctions, and adherens junction signaling pathways).

CONCLUSIONS

APS intervention restored the dietary polysaccharide-induced dysfunction of the intestinal barrier by selectively promoting the abundance of Parabacteroides distasonis, and increasing the concentrations of isobutyrate and bile acids (mainly CDCA and DCA). These findings suggest that APS-induced gut microbiota and metabolic niches are promising strategies for enhancing intestinal barrier function.

Enzyme/ROS dual-sensitive nanoplatform with on-demand Celastrol release capacity for enhanced ulcerative colitis therapy by ROS scavenging, microbiota rebalancing, inflammation alleviating

BACKGROUND

The oral administration of drugs for treating ulcerative colitis (UC) is hindered by several factors, including inadequate gastrointestinal stability, insufficient accumulation in colonic lesions, and uncontrolled drug release.

METHODS

A multiple sensitive nano-delivery system comprising β-cyclodextrin (CD) and 4-(hydroxymethyl)phenylboronic acid (PAPE) with enzyme/reactive oxygen species (ROS) sensitivity was developed to load celastrol (Cel) as a comprehensive treatment for UC.

RESULTS

Owing to the positive charge in the site of inflamed colonic mucosa, the negatively charged nanomedicine (Cel/NPs) could efficiently accumulate. Expectedly, Cel/NPs showed excellent localization ability to colon in vitro and in vivo tests. The elevated concentration of ROS and intestinal enzymes in the colon microenvironment quickly break the CD, resulting in Cel release partially to rebalance microbiota and recover the intestinal barrier. The accompanying cellular internalization of residual Cel/NPs, along with the high concentration of cellular ROS to trigger Cel burst release, could decrease the expression of inflammatory cytokines, inhibit colonic cell apoptosis, promote the macrophage polarization, scavenge ROS, and regulate the TLR4/NF-κB signaling pathway, which certified that Cel/NPs possessed a notably anti-UC therapy outcome.

CONCLUSIONS

We provide a promising strategy for addressing UC symptoms via an enzyme/ROS-sensitive oral platform capable of releasing drugs on demand.

Role of gut/liver metabolites and gut microbiota in liver fibrosis caused by cholestasis

AIM OF THE STUDY

Cholestasis induces severe liver injury and subsequent liver fibrosis. However, a comprehensive understanding of the relationships between liver fibrosis and cholestasis-induced changes in metabolites in the gut and fibrotic liver tissue and in the gut microbiota is insufficient.

METHODS

Common bile duct ligation (BDL) was employed to establish a cholestatic liver fibrosis model in mice for 26 days. Fibrotic liver tissue and the gut contents were collected. Untargeted metabolomics was conducted for the determination of metabolites in the gut contents and liver tissues. Metagenomics was adopted to explore the gut microbiota.

RESULTS

The metabolites in the gut contents and liver tissues between normal and cholestatic liver fibrosis mice were highly distinct. Beta-alanine metabolism and glutathione metabolism were downregulated in the gut of the BDL group. Galactose metabolism, biosynthesis of unsaturated fatty acids, and ABC transporters were upregulated in the gut and downregulated in the liver of the BDL group. Arginine biosynthesis, taurine and hypotaurine metabolism, arginine and proline metabolism, and primary bile acid biosynthesis were downregulated in the gut and upregulated in the liver of the BDL group. Metagenomic analysis revealed that the alpha diversity of the microbiota in the BDL group decreased. The altered structure of the gut microbiota in the BDL group led to the hypofunction of important metabolic pathways (such as folate biosynthesis, histidine metabolism, thiamine metabolism, biotin metabolism, and phenylalanine, tyrosine and tryptophan biosynthesis) and enzymes (such as NADH, DNA helicase, and DNA-directed DNA polymerase). Correlation analyses indicated that certain gut microbes were associated with gut and liver metabolites.

CONCLUSIONS

Untargeted metabolomics and metagenomics provided comprehensive information on gut and liver metabolism and gut microbiota in mice with cholestatic liver fibrosis. Therefore, significantly altered bacteria and metabolites may help provide some targets against cholestatic liver fibrosis in the future.

Rumen and hindgut microbiome regulate average daily gain of preweaning Holstein heifer calves in different ways

BACKGROUND

The average daily gain (ADG) of preweaning calves significantly influences their adult productivity and reproductive performance. Gastrointestinal microbes are known to exert an impact on host phenotypes, including ADG. The aim of this study was to investigate the mechanisms by which gastrointestinal microbiome regulate ADG in preweaning calves and to further validate them by isolating ADG-associated rumen microbes in vitro.

RESULTS

Sixteen Holstein heifer calves were selected from a cohort with 106 calves and divided into higher ADG (HADG; n = 8) and lower ADG (LADG; n = 8) groups. On the day of weaning, samples of rumen contents, hindgut contents, and plasma were collected for rumen metagenomics, rumen metabolomics, hindgut metagenomics, hindgut metabolomics, and plasma metabolomics analyses. Subsequently, rumen contents of preweaning Holstein heifer calves from the same dairy farm were collected to isolate ADG-associated rumen microbes. The results showed that the rumen microbes, including Pyramidobacter sp. C12-8, Pyramidobacter sp. CG50-2, Pyramidobacter porci, unclassified_g_Pyramidobacter, Pyramidobacter piscolens, and Acidaminococcus fermentans, were enriched in the rumen of HADG calves (LDA > 2, P < 0.05). Enrichment of these microbes in HADG calves' rumen promoted carbohydrate degradation and volatile fatty acid production, increasing proportion of butyrate in the rumen and ultimately contributing to higher preweaning ADG in calves (P < 0.05). The presence of active carbohydrate degradation in the rumen was further suggested by the negative correlation of the rumen microbes P. piscolens, P. sp. C12-8 and unclassified_g_Pyramidobacter with the rumen metabolites D-fructose (R <  - 0.50, P < 0.05). Widespread positive correlations were observed between rumen microbes (such as P. piscolens, P. porci, and A. fermentans) and beneficial plasma metabolites (such as 1-pyrroline-5-carboxylic acid and 4-fluoro-L-phenylalanine), which were subsequently positively associated with the growth rate of HADG calves (R > 0.50, P < 0.05). We succeeded in isolating a strain of A. fermentans from the rumen contents of preweaning calves and named it Acidaminococcus fermentans P41. The in vitro cultivation revealed its capability to produce butyrate. In vitro fermentation experiments demonstrated that the addition of A. fermentans P41 significantly increased the proportion of butyrate in the rumen fluid (P < 0.05). These results further validated our findings. The relative abundance of Bifidobacterium pseudolongum in the hindgut of HADG calves was negatively correlated with hindgut 4-hydroxyglucobrassicin levels, which were positively correlated with plasma 4-hydroxyglucobrassicin levels, and plasma 4-hydroxyglucobrassicin levels were positively correlated with ADG (P < 0.05).

CONCLUSIONS

This study's findings unveil that rumen and hindgut microbes play distinctive roles in regulating the preweaning ADG of Holstein heifer calves. Additionally, the successful isolation of A. fermentans P41 not only validated our findings but also provided a valuable strain resource for modulating rumen microbes in preweaning calves. Video Abstract.

Parabacteroides distasonis regulates the infectivity and pathogenicity of SVCV at different water temperatures

BACKGROUND

Spring viremia of carp virus (SVCV) infects a wide range of fish species and causes high mortality rates in aquaculture. This viral infection is characterized by seasonal outbreaks that are temperature-dependent. However, the specific mechanism behind temperature-dependent SVCV infectivity and pathogenicity remains unclear. Given the high sensitivity of the composition of intestinal microbiota to temperature changes, it would be interesting to investigate if the intestinal microbiota of fish could play a role in modulating the infectivity of SVCV at different temperatures.

RESULTS

Our study found that significantly higher infectivity and pathogenicity of SVCV infection in zebrafish occurred at relatively lower temperature. Comparative analysis of the intestinal microbiota in zebrafish exposed to high- and low-temperature conditions revealed that temperature influenced the abundance and diversity of the intestinal microbiota in zebrafish. A significantly higher abundance of Parabacteroides distasonis and its metabolite secondary bile acid (deoxycholic acid, DCA) was detected in the intestine of zebrafish exposed to high temperature. Both colonization of Parabacteroides distasonis and feeding of DCA to zebrafish at low temperature significantly reduced the mortality caused by SVCV. An in vitro assay demonstrated that DCA could inhibit the assembly and release of SVCV. Notably, DCA also showed an inhibitory effect on the infectious hematopoietic necrosis virus, another Rhabdoviridae member known to be more infectious at low temperature.

CONCLUSIONS

This study provides evidence that temperature can be an important factor to influence the composition of intestinal microbiota in zebrafish, consequently impacting the infectivity and pathogenicity of SVCV. The findings highlight the enrichment of Parabacteroides distasonis and its derivative, DCA, in the intestines of zebrafish raised at high temperature, and they possess an important role in preventing the infection of SVCV and other Rhabdoviridae members in host fish. Video Abstract.

Gut microbiota Parabacteroides distasonis enchances the efficacy of immunotherapy for bladder cancer by activating anti-tumor immune responses

OBJECTIVE

Bladder cancer(BCa) was a disease that seriously affects patients' quality of life and prognosis. To address this issue, many researches suggested that the gut microbiota modulated tumor response to treatment; however, this had not been well-characterized in bladder cancer. In this study, our objective was to determine whether the diversity and composition of the gut microbiota or the density of specific bacterial genera influence the prognosis of patients with bladder cancer.

METHODS

We collected fecal samples from a total of 50 bladder cancer patients and 22 matched non-cancer individuals for 16S rDNA sequencing to investigate the distribution of Parabacteroides in these two groups. Further we conducted follow-up with cancer patients to access the impact of different genera of microorganisms on patients survival. We conducted a Fecal Microbiota Transplantation (FMT) and mono-colonization experiment with Parabacteroides distasonis to explore its potential enhancement of the efficacy of anti-PD-1 immunotherapy in MB49 tumor-bearing mice. Immunohistochemistry, transcriptomics and molecular experiment analyses were employed to uncover the underlying mechanisms.

RESULTS

The 16S rDNA showed that abundance of the genus Parabacteroides was elevated in the non-cancer control group compared to bladder cancer group. The results of tumor growth curves showed that a combination therapy of P. distasonis and ICIs treatment significantly delayed tumor growth and increased the intratumoral densities of both CD4+T and CD8+T cells. The results of transcriptome analysis demonstrated that the pathways associated with antitumoral immune response were remarkably upregulated in the P. distasonis gavage group.

CONCLUSION

P. distasonis delivery combined with α-PD-1 mAb could be a new strategy to enhance the effect of anti-PD-1 immunotherapy. This effect might be achieved by activating immune and antitumor related pathways.