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Cellular and Molecular Gastroenterology... 2024A long immune-tolerant (IT) phase lasting for decades and delayed HBeAg seroconversion (HBe-SC) in patients with chronic hepatitis B (CHB) increase the risk of liver...
BACKGROUND & AIMS
A long immune-tolerant (IT) phase lasting for decades and delayed HBeAg seroconversion (HBe-SC) in patients with chronic hepatitis B (CHB) increase the risk of liver diseases. Early entry into the immune-active (IA) phase and HBe-SC confers a favorable clinical outcome with an unknown mechanism. We aimed to identify factor(s) triggering IA entry and HBe-SC in the natural history of CHB.
METHODS
To study the relevance of gut microbiota evolution in the risk of CHB activity, fecal samples were collected from CHB patients (n = 102) in different disease phases. A hepatitis B virus (HBV)-hydrodynamic injection (HDI) mouse model was therefore established in several mouse strains and germ-free mice, and multiplatform metabolomic and bacteriologic assays were performed.
RESULTS
Ruminococcus gnavus was the most abundant species in CHB patients in the IT phase, whereas Akkermansia muciniphila was predominantly enriched in IA patients and associated with alanine aminotransferase flares, HBeAg loss, and early HBe-SC. HBV-HDI mouse models recapitulated this human finding. Increased cholesterol-to-bile acids (BAs) metabolism was found in IT patients because R gnavus encodes bile salt hydrolase to deconjugate primary BAs and augment BAs total pool for facilitating HBV persistence and prolonging the IT course. A muciniphila counteracted this activity through the direct removal of cholesterol. The secretome metabolites of A muciniphila, which contained small molecules structurally similar to apigenin, lovastatin, ribavirin, etc., inhibited the growth and the function of R gnavus to allow HBV elimination.
CONCLUSIONS
R gnavus and A muciniphila play opposite roles in HBV infection. A muciniphila metabolites, which benefit the elimination of HBV, may contribute to future anti-HBV strategies.
Topics: Animals; Humans; Mice; Akkermansia; Cholesterol; Clostridiales; Hepatitis B e Antigens; Hepatitis B, Chronic; Gastrointestinal Microbiome
PubMed: 38092311
DOI: 10.1016/j.jcmgh.2023.12.003 -
Anaerobe Feb 2024Ruminococcus gnavus is a rare human pathogen, and clinical data on R. gnavus infection are insufficient. This retrospective study aimed to investigate the clinical...
OBJECTIVES
Ruminococcus gnavus is a rare human pathogen, and clinical data on R. gnavus infection are insufficient. This retrospective study aimed to investigate the clinical characteristics of R. gnavus infections.
METHODS
This study included 13 cases of bacteremia and three cases of non-bacteremia infections caused by R. gnavus. We evaluated the patient data, infection source, clinical outcomes, and antimicrobial susceptibility of R. gnavus isolates for these cases.
RESULTS
The median age of patients was 75 years (range 47-95), and eight patients were female. Twelve cases were presumed to have an intra-abdominal infection source, and the remaining four cases had an unknown infection source. The most common underlying conditions were immunosuppression (seven cases), solid tumors (seven cases), and history of gastrointestinal surgery (five cases). Thirteen patients exhibited gastrointestinal problems (dysfunction, bleeding, intra-abdominal infection, or inflammation). Multiple pathogens were observed in six cases, and fatal outcomes were recorded in three cases. Antimicrobial susceptibility data were available for eight isolates, all of which exhibited low minimum inhibitory concentrations to penicillin (≤0.03 μg/mL), ampicillin-sulbactam (≤0.5 μg/mL), piperacillin-tazobactam (≤4 μg/mL), and metronidazole (≤0.5-1 μg/mL).
CONCLUSION
Ruminococcus gnavus is frequently associated with an intra-abdominal infection source, and treatment strategies should consider the possibility of multiple pathogens.
Topics: Humans; Female; Middle Aged; Aged; Aged, 80 and over; Male; Ruminococcus; Retrospective Studies; Intraabdominal Infections; Bacteremia; Anti-Infective Agents; Anti-Bacterial Agents; Clostridiales
PubMed: 38211774
DOI: 10.1016/j.anaerobe.2024.102818 -
Microbial Genomics Jul 2023is prevalent in the intestines of humans and animals, and ambiguities have been reported regarding its relations with the development of diseases and host well-being....
is prevalent in the intestines of humans and animals, and ambiguities have been reported regarding its relations with the development of diseases and host well-being. We postulate the ambiguities of its function in different cases may be attributed to strain-level variability of genomic features of . We performed comparative genomic and pathogenicity prediction analysis on 152 filtered high-quality genomes, including 4 genomes of strains isolated from healthy adults in this study. The mean G+C content of genomes of was 42.73±0.33 mol%, and the mean genome size was 3.46±0.34 Mbp. Genome-wide evolutionary analysis revealed genomes were divided into three major phylogenetic clusters. Pan-core genome analysis revealed that there was a total of 28 072 predicted genes, and the core genes, soft-core genes, shell genes and cloud genes accounted for 3.74 % (1051/28 072), 1.75 % (491/28 072), 9.88 % (2774/28 072) and 84.63 % (23 756/28 072) of the total genes, respectively. The small proportion of core genes reflected the wide divergence among strains. We found certain coding sequences with determined health benefits (such as vitamin production and arsenic detoxification), whilst some had an implication of health adversity (such as sulfide dehydrogenase subunits). The functions of the majority of core genes were unknown. The most widespread genes functioning in antibiotic resistance and virulence are (tetracycline-resistance gene, present in 75 strains) and (capsular polysaccharide biosynthesis protein Cps4J encoding gene, detected in 3 genomes), respectively. Our results revealed genomic divergence and the existence of certain safety-relevant factors of . This study provides new insights for understanding the genomic features and health relevance of , and raises concerns regarding predicted prevalent pathogenicity and antibiotic resistance among most of the strains.
Topics: Adult; Animals; Humans; Ruminococcus; Phylogeny; Clostridiales; Genomics
PubMed: 37486746
DOI: 10.1099/mgen.0.001071 -
Gut Microbes 2022is a prevalent member of the human gut microbiota, which is over-represented in inflammatory bowel disease and neurological disorders. We previously showed that the...
is a prevalent member of the human gut microbiota, which is over-represented in inflammatory bowel disease and neurological disorders. We previously showed that the ability of to forage on mucins is strain-dependent and associated with sialic acid metabolism. Here, we showed that mice monocolonized with ATCC 29149 (-mice) display changes in major sialic acid derivatives in their cecum content, blood, and brain, which is accompanied by a significant decrease in the percentage of sialylated residues in intestinal mucins relative to germ-free (GF) mice. Changes in metabolites associated with brain function such as tryptamine, indolacetate, and trimethylamine -oxide were also detected in the cecal content of -mice when compared to GF mice. Next, we investigated the effect of monocolonization on hippocampus cell proliferation and behavior. We observed a significant decrease of PSA-NCAM immunoreactive granule cells in the dentate gyrus (DG) of -mice as compared to GF mice and recruitment of phagocytic microglia in the vicinity. Behavioral assessments suggested an improvement of the spatial working memory in -mice but no change in other cognitive functions. These results were also supported by a significant upregulation of genes involved in proliferation and neuroplasticity. Collectively, these data provide first insights into how metabolites may influence brain regulation and function through modulation of granule cell development and synaptic plasticity in the adult hippocampus. This work has implications for further understanding the mechanisms underpinning the role of in neurological disorders.
Topics: Animals; Brain; Clostridiales; Gastrointestinal Microbiome; Mice; Mucins; N-Acetylneuraminic Acid; Polysaccharides
PubMed: 35579971
DOI: 10.1080/19490976.2022.2073784 -
ImmunoHorizons Mar 2023Epithelium-derived antimicrobial peptides represent an evolutionarily ancient defense mechanism against pathogens. Regenerating islet-derived protein 3 γ (Reg3γ), the...
Epithelium-derived antimicrobial peptides represent an evolutionarily ancient defense mechanism against pathogens. Regenerating islet-derived protein 3 γ (Reg3γ), the archetypal intestinal antimicrobial peptide, is critical for maintaining host-microbe interactions. Expression of Reg3γ is known to be regulated by the microbiota through two different pathways, although it remains unknown whether specific Reg3γ-inducing bacteria act via one or both of these pathways. In recent work, we identified Ruminococcus gnavus and Limosilactobacillus reuteri as commensal bacteria able to induce Reg3g expression. In this study, we show these bacteria require myeloid differentiation primary response protein 88 and group 3 innate lymphoid cells for induction of Reg3γ in mice. Interestingly, we find that R. gnavus and L. reuteri suppress Reg3γ in the absence of either myeloid differentiation primary response protein 88 or group 3 innate lymphoid cells. In addition, we demonstrate that colonization by these bacteria is not required for induction of Reg3γ, which occurs several days after transient exposure to the organisms. Taken together, our findings highlight the complex mechanisms underlying microbial regulation of Reg3γ.
Topics: Animals; Mice; Bacteria; Immunity, Innate; Limosilactobacillus reuteri; Lymphocytes; Proteins; Ruminococcus
PubMed: 36943156
DOI: 10.4049/immunohorizons.2200096 -
Journal of Applied Microbiology May 2016The molecular cross-talk between commensal bacteria and the gut play an important role in the maintenance of the intestinal homeostasis and general health. Here, we...
AIMS
The molecular cross-talk between commensal bacteria and the gut play an important role in the maintenance of the intestinal homeostasis and general health. Here, we studied the impact of a major Gram-positive anaerobic bacterium of the human gut microbiota, that is, Ruminococcus gnavus on the glycosylation pattern and the production of intestinal mucus by the goblet cells.
METHODS AND RESULTS
Our results showed that R. gnavus E1 specifically increases the expression and the glycosylation level of the intestinal glyco-conjugates by goblet cells in the colonic mucosa of mono-associated mice with R. gnavus E1 as well as in human HT29-MTX cells. Such an effect was mediated through induction of the level of mRNA encoding for the major intestinal gel-forming mucin such as MUC2 and various glycosyltransferase enzymes.
CONCLUSIONS
This study demonstrates for the first time that R. gnavus E1 possess the ability to modulate the glycosylation profile of the glyco-conjugate molecules and mucus in goblet cells.
SIGNIFICANCE AND IMPACT OF THE STUDY
Furthermore, we demonstrated that R. gnavus E1 modified specifically the glycosylation pattern and MUC2 expression by means of a small soluble factor of peptidic nature (<3 kDa) and heat stable in the HT29-MTX cell.
Topics: Animals; Colon; Gastrointestinal Microbiome; Glycosylation; Goblet Cells; HT29 Cells; Humans; Intestinal Mucosa; Intestines; Mice; Mucins; Ruminococcus
PubMed: 26868655
DOI: 10.1111/jam.13095 -
Gut Microbes 2023The prevalence and occurrence of mucin-degrading (MD) bacteria, such as and , is highly associated with human health and disease states. However, MD bacterial...
The prevalence and occurrence of mucin-degrading (MD) bacteria, such as and , is highly associated with human health and disease states. However, MD bacterial physiology and metabolism remain elusive. Here, we assessed functional modules of mucin catabolism, through a comprehensive bioinformatics-aided functional annotation, to identify 54 genes and 296 genes. The reconstructed core metabolic pathways coincided with the growth kinetics and fermentation profiles of and grown in the presence of mucin and its constituents. Genome-wide multi-omics analyses validated the nutrient-dependent fermentation profiles of the MD bacteria and identified their distinct mucolytic enzymes. The distinct metabolic features of the two MD bacteria induced differences in the metabolite receptor levels and inflammatory signals of the host immune cells. In addition, experiments and community-scale metabolic modeling demonstrated that different dietary intakes influenced the abundance of MD bacteria, their metabolic fluxes, and gut barrier integrity. Thus, this study provides insights into how diet-induced metabolic differences in MD bacteria determine their distinct physiological roles in the host immune response and the gut ecosystem.
Topics: Humans; Mucins; Multiomics; Ecosystem; Gastrointestinal Microbiome; Bacteria
PubMed: 37305974
DOI: 10.1080/19490976.2023.2221811 -
Nutrients Jul 2023The gut microbiota is a dynamic community of bacteria distributed in the gastroenteric tract and changes in response to diseases, diet, use of antibiotics and... (Review)
Review
The gut microbiota is a dynamic community of bacteria distributed in the gastroenteric tract and changes in response to diseases, diet, use of antibiotics and probiotics, hygiene status, and other environmental factors. Dysbiosis, a disruption of the normal crosstalk between the host and the microbes, is associated with obesity, diabetes, cancer, and cardiovascular diseases, is linked to a reduction of anti-inflammatory bacteria like and , and to an increase in the growth of proinflammatory species like and . Some plants possess anticancer properties and various studies have reported that some of these are also able to modulate the gut microbiota. The aim of this work is to evaluate the crucial relationship between medical plants and gut microbiota and the consequences on the onset and progression of cancer. In vivo studies about hematological malignancies showed that beta-glucans tie to endogenous antibeta glucan antibodies and to iC3b, an opsonic fragment of the central complement protein C3, leading to phagocytosis of antibody-targeted neoplastic cells and potentiation of the cytotoxic activity of the innate immune system if administered together with monoclonal antibodies. In conclusion, this review suggests the potential use of medical plants to improve gut dysbiosis and assist in the treatment of cancer.
Topics: Humans; Gastrointestinal Microbiome; Dysbiosis; Obesity; Bacteria; Diet; Neoplasms; Probiotics
PubMed: 37571264
DOI: 10.3390/nu15153327 -
Rheumatology and Immunology Research Dec 2023The gut microbiome represents a potential promising therapeutic target for autoimmune diseases. This review summarizes the current knowledge on the links between the gut...
The gut microbiome represents a potential promising therapeutic target for autoimmune diseases. This review summarizes the current knowledge on the links between the gut microbiome and several autoimmune rheumatic diseases including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) spondyloarthropathies (SpA), Sjogren's syndrome (SS), and systemic sclerosis (SSc). Evidence from studies of RA and SLE patients suggests that alterations in the gut microbiome composition and function contribute to disease development and progression through increased gut permeability, with microbes and microbial metabolites driving an excessive systemic activation of the immune system. Also, there is growing evidence that gut dysbiosis and subsequent immune cell activation may contribute to disease pathogenesis in SpA and SS. For SSc, there are fewer, but these are still informative, reports on alterations in the gut microbiome. In general, the complex interplay between the microbiome and the immune system is still not fully understood. Here we discuss the current knowledge of the link between the gut microbiome and autoimmune rheumatic diseases, highlighting potentially fertile areas for future research and make considerations on the potential benefits of strategies that restore gut microbiome homeostasis.
PubMed: 38125641
DOI: 10.2478/rir-2023-0027 -
Scientific Reports Nov 2022Moyamoya disease (MMD) is a rare cerebrovascular disease endemic in East Asia. The p.R4810K mutation in RNF213 gene confers a risk of MMD, but other factors remain...
Moyamoya disease (MMD) is a rare cerebrovascular disease endemic in East Asia. The p.R4810K mutation in RNF213 gene confers a risk of MMD, but other factors remain largely unknown. We tested the association of gut microbiota with MMD. Fecal samples were collected from 27 patients with MMD, 7 patients with non-moyamoya intracranial large artery disease (ICAD) and 15 control individuals with other disorders, and 16S rRNA were sequenced. Although there was no difference in alpha diversity or beta diversity between patients with MMD and controls, the cladogram showed Streptococcaceae was enriched in patient samples. The relative abundance analysis demonstrated that 23 species were differentially abundant between patients with MMD and controls. Among them, increased abundance of Ruminococcus gnavus > 0.003 and decreased abundance of Roseburia inulinivorans < 0.002 were associated with higher risks of MMD (odds ratio 9.6, P = 0.0024; odds ratio 11.1, P = 0.0051). Also, Ruminococcus gnavus was more abundant and Roseburia inulinivorans was less abundant in patients with ICAD than controls (P = 0.046, P = 0.012). The relative abundance of Ruminococcus gnavus or Roseburia inulinivorans was not different between the p.R4810K mutant and wildtype. Our data demonstrated that gut microbiota was associated with both MMD and ICAD.
Topics: Humans; Moyamoya Disease; Gastrointestinal Microbiome; RNA, Ribosomal, 16S; Ruminococcus; Intracranial Arterial Diseases; Rare Diseases; Arteries; Adenosine Triphosphatases; Ubiquitin-Protein Ligases
PubMed: 36424438
DOI: 10.1038/s41598-022-24496-9