Bacteria-Induced Group 2 Innate Lymphoid Cells in the Stomach Provide Immune Protection through Induction of IgA.

The intestinal microbiota shapes and directs immune development locally and systemically, but little is known about whether commensal microbes in the stomach can impact their immunological microenvironment. Here, we report that group 2 innate lymphoid cells (ILC2s) were the predominant ILC subset in the stomach and show that their homeostasis and effector functions were regulated by local commensal communities. Microbes elicited interleukin-7 (IL-7) and IL-33 production in the stomach, which in turn triggered the propagation and activation of ILC2. Stomach ILC2s were also rapidly induced following infection with Helicobacter pylori. ILC2-derived IL-5 resulted in the production of IgA, which coated stomach bacteria in both specific pathogen-free (SPF) and H. pylori-infected mice. Our study thus identifies ILC2-dependent IgA response that is regulated by the commensal microbiota, which is implicated in stomach protection by eliminating IgA-coated bacteria including pathogenic H. pylori.

Acetate differentially regulates IgA reactivity to commensal bacteria.

The balance between bacterial colonization and its containment in the intestine is indispensable for the symbiotic relationship between humans and their bacteria. One component to maintain homeostasis at the mucosal surfaces is immunoglobulin A (IgA), the most abundant immunoglobulin in mammals1,2. Several studies have revealed important characteristics of poly-reactive IgA3,4, which is produced naturally without commensal bacteria. Considering the dynamic changes within the gut environment, however, it remains uncertain how the commensal-reactive IgA pool is shaped and how such IgA affects the microbial community. Here we show that acetate-one of the major gut microbial metabolites-not only increases the production of IgA in the colon, but also alters the capacity of the IgA pool to bind to specific microorganisms including Enterobacterales. Induction of commensal-reactive IgA and changes in the IgA repertoire by acetate were observed in mice monocolonized with Escherichia coli, which belongs to Enterobacterales, but not with the major commensal Bacteroides thetaiotaomicron, which suggests that acetate directs selective IgA binding to certain microorganisms. Mechanistically, acetate orchestrated the interactions between epithelial and immune cells, induced microbially stimulated CD4 T cells to support T-cell-dependent IgA production and, as a consequence, altered the localization of these bacteria within the colon. Collectively, we identified a role for gut microbial metabolites in the regulation of differential IgA production to maintain mucosal homeostasis.

Gut microbiota and fecal metabolites in sustained unresponsiveness by oral immunotherapy in school-age children with cow's milk allergy.

BACKGROUND: Oral immunotherapy (OIT) can ameliorate cow's milk allergy (CMA); however, the achievement of sustained unresponsiveness (SU) is challenging. Regarding the pathogenesis of CMA, recent studies have shown the importance of gut microbiota (Mb) and fecal water-soluble metabolites (WSMs), which prompted us to determine the change in clinical and gut environmental factors important for acquiring SU after OIT for CMA. METHODS: We conducted an ancillary cohort study of a multicenter randomized, parallel-group, delayed-start design study on 32 school-age children with IgE-mediated CMA who underwent OIT for 13 months. We defined SU as the ability to consume cow's milk exceeding the target dose in a double-blind placebo-controlled food challenge after OIT followed by a 2-week-avoidance. We longitudinally collected 175 fecal specimens and clustered the microbiome and metabolome data into 29 Mb- and 12 WSM-modules. RESULTS: During OIT, immunological factors improved in all participants. However, of the 32 participants, 4 withdrew because of adverse events, and only 7 were judged SU. Gut environmental factors shifted during OIT, but only in the beginning, and returned to the baseline at the end. Of these factors, milk- and casein-specific IgE and the Bifidobacterium-dominant module were associated with SU (milk- and casein-specific IgE; OR for 10 kUA/L increments, 0.67 and 0.66; 95%CI, 0.41-0.93 and 0.42-0.90; Bifidobacterium-dominant module; OR for 0.01 increments, 1.40; 95%CI, 1.10-2.03), and these associations were observed until the end of OIT. CONCLUSIONS: In this study, we identified the clinical and gut environmental factors associated with SU acquisition in CM-OIT.

Amendment of a thermophile-fermented compost to humus improves the growth of female larvae of the Hercules beetle Dynastes hercules (Coleoptera: scarabaeidae).

AIMS: Hercules beetle is a popular pet and large adult individuals are considered valuable. Incorporating compost prepared from marine animals and fermented by thermophilic bacteria into the humus benefits the gut microflora of several livestock. Here, we evaluated whether this compost improves the growth of the Hercules beetle (Dynastes hercules hercules) larvae. METHODS AND RESULTS: We mixed the compost grains with the humus at a final concentration of 1% (w/w) and transferred ∼90 days old Hercules beetle larvae to fresh humus with or without the compost. After 72 days rearing period, only the female larvae reared in the humus with compost exhibited superior growth, compared with those grown in compost-free humus. The gut bacterial composition was determined at 0 and 46 day after transferring the larvae to humus with or without compost. Improved growth of the female larvae was associated with increased abundance of Mollicutes and decreased abundance of Gammaproteobacteria. CONCLUSION: The thermophile-fermented compost has a probiotic effect on the female Hercules beetle larvae that is mediated by altered gut microflora.

Computational estimation of sediment symbiotic bacterial structures of seagrasses overgrowing downstream of onshore aquaculture.

Coastal seagrass meadows are essential in blue carbon and aquatic ecosystem services. However, this ecosystem has suffered severe eutrophication and destruction due to the expansion of aquaculture. Therefore, methods for the flourishing of seagrass are still being explored. Here, data from 49 public coastal surveys on the distribution of seagrass and seaweed around the onshore aquaculture facilities are revalidated, and an exceptional area where the seagrass Zostera marina thrives was found near the shore downstream of the onshore aquaculture facility. To evaluate the characteristics of the sediment for growing seagrass, physicochemical properties and bacterial ecological evaluations of the sediment were conducted. Evaluation of chemical properties in seagrass sediments confirmed a significant increase in total carbon and a decrease in zinc content. Association analysis and linear discriminant analysis refined bacterial candidates specified in seagrass overgrown- and nonovergrown-sediment. Energy landscape analysis indicated that the symbiotic bacterial groups of seagrass sediment were strongly affected by the distance close to the seagrass-growing aquaculture facility despite their bacterial population appearing to fluctuate seasonally. The bacterial population there showed an apparent decrease in the pathogen candidates belonging to the order Flavobacteriales. Moreover, structure equation modeling and a linear non-Gaussian acyclic model based on the machine learning data estimated an optimal sediment symbiotic bacterial group candidate for seagrass growth as follows: the Lachnospiraceae and Ruminococcaceae families as gut-inhabitant bacteria, Rhodobacteraceae as photosynthetic bacteria, and Desulfobulbaceae as cable bacteria modulating oxygen or nitrate reduction and oxidation of sulfide. These observations confer a novel perspective on the sediment symbiotic bacterial structures critical for blue carbon and low-pathogenic marine ecosystems in aquaculture.

Development of a novel feeding method for Japanese black calves with thermophile probiotics at postweaning.

AIMS: Probiotic effects of compost containing thermophiles on productivity have been reported in domestic animals, although not cattle. We evaluated the effects of administering Caldibacillus hisashii, a thermophile contained in compost, on growth, blood components, faecal organic acid concentrations and microbiota population in Japanese black calves. METHODS AND RESULTS: Calves were administered C. hisashii from 3 to 5 months of age. Administering C. hisashii decreased feed intake without affecting body weight, indicating that feed efficiency is improved by administration. Administering C. hisashii decreased plasma insulin concentration without affecting glucose and non-esterified fatty acid concentrations. Chao1 was decreased by exposure at 5 months of age. Similarly, weighted and unweighted UniFrac distances were affected by treatment at 5 months of age. Faecal abundance of the phylum Bacteroidetes tended to be increased by exposure. Faecal propionic acid concentration was correlated positively with faecal abundance of phylum Bacteroidetes but negatively with that of Firmicutes. Interestingly, the population of the genus Methanobrevibacter, representing the majority of methanogens, was lowered by exposure and was negatively correlated with faecal propionic acid concentration. CONCLUSION: Administration of C. hisashii has the potential to improve growth performance of Japanese black calves and to contribute to reducing environmental load, which may be associated with altered endocrine kinetics and gut microbial populations. SIGNIFICANCE AND IMPACT OF THE STUDY: This study revealed that isolated thermophiles included in compost may exert probiotic effects on calves.

Integrated Multi-Omics Analysis Reveals Differential Effects of Fructo-Oligosaccharides (FOS) Supplementation on the Human Gut Ecosystem.

Changes in the gut ecosystem, including the microbiome and the metabolome, and the host immune system after fructo-oligosaccharide (FOS) supplementation were evaluated. The supplementation of FOS showed large inter-individual variability in the absolute numbers of fecal bacteria and an increase in Bifidobacterium. The fecal metabolome analysis revealed individual variability in fructose utilization in response to FOS supplementation. In addition, immunoglobulin A(IgA) tended to increase upon FOS intake, and peripheral blood monocytes significantly decreased upon FOS intake and kept decreasing in the post-FOS phase. Further analysis using a metagenomic approach showed that the differences could be at least in part due to the differences in gene expressions of enzymes that are involved in the fructose metabolism pathway. While the study showed individual differences in the expected health benefits of FOS supplementation, the accumulation of "personalized" knowledge of the gut ecosystem with its genetic expression may enable effective instructions on prebiotic consumption to optimize health benefits for individuals in the future.

Role of a new bioassay for thyroid-stimulating antibodies (aequorin TSAb) in Graves' ophthalmopathy.

Graves' ophthalmopathy (GO) is characterized by an autoimmune reaction against thyrotropin (TSH) receptors and is diagnosed by TSH receptor antibody (TRAb). A novel assay for thyroid-stimulating antibody (TSAb) was recently introduced using a frozen Chinese hamster ovary cell line expressing TSH receptors, cyclic adenosine monophosphate (cAMP)-gated calcium channel, and aequorin (aequorin TSAb). The aim of this study was to evaluate the role of aequorin TSAb in GO. We studied 136 Japanese patients with GO (22 euthyroid and 8 hypothyroid GO patients) at our hospital. TRAbs were estimated by first generation TRAb (TRAb 1st), second generation TRAb (hTRAb 2nd), conventional porcine TSAb, and the new aequorin TSAb assays. Aequorin TSAb, porcine TSAb, TRAb 1st, and hTRAb 2nd were positive in 125/136 (92%), 110/136 (81%), 81/130 (62%), and 93/114 (82%) patients, respectively. In patients with hyperthyroid GO, they were positive in 98/106 (98%), 96/106 (91%), 78/101 (77%), and 84/93 (90%) patients, respectively. In patients with euthyroid GO, they were positive in 19/22 (86%), 9/22 (41%), 1/21 (5%), and 6/17 (35%) patients, respectively. Aequorin TSAb levels were significantly related to TRAb 1st (r = 0.4172, p < 0.0001), hTRAb 2nd (r = 0.2592, p < 0.0001), and porcine TSAb (r = 0.4665, p < 0.0001). Clinical activity score (CAS) was significantly greater in patients with high titers of aequorin TSAb than in those with low titers. Aequorin TSAb levels were significantly related to the signal intensity ratio of the enlarged eye muscle and proptosis evaluated by MRI before steroid pulse therapy. Aequorin TSAb assay was more sensitive than the conventional assays, especially in euthyroid GO.

Lactobacillus sp. improved microbiota and metabolite profiles of aging rats.

Aging is closely associated with altered gut function and composition, in which elderly were reported with reduced gut microbiota diversity and increased incidence of age-related diseases. Probiotics have been shown to exert beneficial health-promoting effects through modulation of intestinal microflora biodiversity, thus the effects of probiotics administration on D-galactose (D-gal) senescence-induced rat were evaluated based on the changes in gut microbiota and metabolomic profiles. Upon senescence induction, the ratio of Firmicutes/ Bacteroidetes was significantly lowered, while treatment with Lactobacillus helveticus OFS 1515 and L. fermentum DR9 increased the ratio at the phylum level (P < 0.05). Study on the genus level showed that L. paracasei OFS 0291 and L. helveticus OFS 1515 administration reduced Bacteroides, which are prominently opportunistic pathogens while L. fermentum DR9 treated rats promoted the proliferation of Lactobacillus compared to the aged rats (P < 0.05). Probiotics treatment did not alter fecal short-chain fatty acid (SCFA) profile, but an increase in acetate was observed in the D-gal rats. The analysis of fecal water-soluble metabolites showed that D-gal induced senescence caused great impact on amino acids metabolism such as urocanic acid, citrulline, cystamine and 5-oxoproline, which could serve as potential aging biomarkers. Treatment with probiotics ameliorated these metabolites in a strain-specific manner, whereby L. fermentum DR9 promoted antioxidative effect through upregulation of oxoproline, whereas both L. paracasei OFS 0291 and L. helveticus OFS 1515 restored the levels of reducing sugars, arabinose and ribose similar to the young rats. D-gal induced senescence did cause significant immunological alteration in the colon of aged rats however, all probiotic strains demonstrated immunomodulatory properties as L. paracasei OFS 0291, L. helveticus OFS 1515 and L. fermentum DR9 alleviated proinflammatory cytokines TNF-α, IFN-γ and IL-1ß as well as IL-4 compared to the aged control (P < 0.05). Our study highlights the potential of probiotics as an anti-aging therapy through healthy gut modulation.

Commensal microbe-derived butyrate induces the differentiation of colonic regulatory T cells.

Gut commensal microbes shape the mucosal immune system by regulating the differentiation and expansion of several types of T cell. Clostridia, a dominant class of commensal microbe, can induce colonic regulatory T (Treg) cells, which have a central role in the suppression of inflammatory and allergic responses. However, the molecular mechanisms by which commensal microbes induce colonic Treg cells have been unclear. Here we show that a large bowel microbial fermentation product, butyrate, induces the differentiation of colonic Treg cells in mice. A comparative NMR-based metabolome analysis suggests that the luminal concentrations of short-chain fatty acids positively correlates with the number of Treg cells in the colon. Among short-chain fatty acids, butyrate induced the differentiation of Treg cells in vitro and in vivo, and ameliorated the development of colitis induced by adoptive transfer of CD4(+) CD45RB(hi) T cells in Rag1(-/-) mice. Treatment of naive T cells under the Treg-cell-polarizing conditions with butyrate enhanced histone H3 acetylation in the promoter and conserved non-coding sequence regions of the Foxp3 locus, suggesting a possible mechanism for how microbial-derived butyrate regulates the differentiation of Treg cells. Our findings provide new insight into the mechanisms by which host-microbe interactions establish immunological homeostasis in the gut.

NALT M cells are important for immune induction for the common mucosal immune system.

Nasopharynx-associated lymphoid tissue (NALT) is one of the major constituents of the mucosa-associated lymphoid tissue (MALT), and has the ability to induce antigen-specific immune responses. However, the molecular mechanisms responsible for antigen uptake from the nasal cavity into the NALT remain largely unknown. Immunohistochemical analysis showed that CCL9 and CCL20 were co-localized with glycoprotein 2 (GP2) in the epithelium covering NALT, suggesting the existence of M cells in NALT. In analogy with the reduced number of Peyer's patch M cells in CCR6-deficient mice, the number of NALT M cells was drastically decreased in CCR6-deficient mice compared with the wild-type mice. Translocation of nasally administered Salmonella enterica serovar Typhimurium into NALT via NALT M cells was impaired in CCR6-deficient mice, whereas S. Typhimurium demonstrated consistent co-localization with NALT M cells in wild-type mice. When wild-type mice were nasally administered with an attenuated vaccine strain of S. Typhimurium, the mice were protected from a subsequent challenge with wild-type S. Typhimurium. Antigen-specific fecal and nasal IgA was detected after nasal immunization with the attenuated vaccine strain of S. Typhimurium only in wild-type mice but not in CCR6-deficient mice. Taken together, these observations demonstrate that NALT M cells are important as a first line of defense against infection by enabling activation of the common mucosal immune system (CMIS).

Modulation of gut microbiota composition due to early weaning stress induces depressive behavior during the juvenile period in mice.

BACKGROUND: The gut microbiota plays an important role in the development of behavior and immunity in infants and juveniles. Early weaning (EW), a form of social stress in mice, leads to increased anxiety and an enhanced stress response in the hypothalamic-pituitary-adrenal axis during adulthood. Early life stress also modulates the immune system and increases vulnerability to infection. However, studies investigating the causal relationships among juvenile stress, microbiota changes, and immune and behavioral deficits are limited. Therefore, we hypothesized that EW alters gut microbiota composition and impairs the development of the nervous and immune systems. RESULTS: EW mice moved longer distances in the marble-burying test and had longer immobility times in the tail suspension test than normal weaning (NW) mice. In parallel, the gut microbiome composition differed between NW and EW mice, and the abundance of Erysipelotrichacea in EW mice at 8 weeks of age was lower than that in NW mice. In an empirical study, germ-free mice colonized with the gut microbiota of EW mice (GF-EW mice) demonstrated higher depressive behavior than GF mice colonized with normal weaning microbiota (GF-NW mice). Immune cell profiles were also affected by the EW microbiota colonization; the number of CD4 + T cells in the spleen was reduced in GF-EW mice. CONCLUSION: Our results suggest that EW-induced alterations in the gut microbiota cause depressive behaviors and modulate the immune system.

Prevalence and clinical characteristics of unremembered nocturnal eating in diabetic subjects: Kurume sleep trouble in obesity and metabolic disorders (KUSTOMED) study.

Nighttime food intake is associated with weight gain and higher HbA1c levels. We experienced night eaters who have no memory of their nocturnal eating in the morning. In this study, the curious night eating behavior was designated as "unremembered nocturnal eating syndrome (UNES)". We screened 1,169 patients with diabetes for sleep quality and abnormal eating behavior at night using the Pittsburgh Sleep Quality Index questionnaire with an additional question regarding UNES. When abnormal nocturnal eating behavior was noted, detailed clinical information was extracted from interviews with the patients. We identified 9 patients who experienced UNES. They had a higher BMI compared with subjects who reported no such episodes. Among them, 6 patients who consumed food at night without memory 2-5 times per month or more had significantly higher HbA1c levels. Continuous glucose monitoring in a patient with type 1 diabetes revealed an abrupt elevation of glucose levels from midnight when some foods were consumed. Eight of the 9 patients were taking benzodiazepine and/or non-benzodiazepine hypnotic agents when they experienced the episodes. The prevalence of UNES was 0.8% in all subjects and 4% in those taking hypnotic drugs. The ratio of hypnotic drug use in subjects with UNES was significantly higher than for individuals without UNES (89% vs. 17%, p<0.0001). Although UNES seems to be etiologically heterogeneous, hypnotics-induced parasomnia and/or anterograde amnesia may be associated with the behavior. UNES is not rare in diabetic patients on hypnotic medicine and may be a hidden cause of unexpected morning hyperglycemia.

Fatty acid overproduction by gut commensal microbiota exacerbates obesity.

Although recent studies have highlighted the impact of gut microbes on the progression of obesity and its comorbidities, it is not fully understood how these microbes promote these disorders, especially in terms of the role of microbial metabolites. Here, we report that Fusimonas intestini, a commensal species of the family Lachnospiraceae, is highly colonized in both humans and mice with obesity and hyperglycemia, produces long-chain fatty acids such as elaidate, and consequently facilitates diet-induced obesity. High fat intake altered the expression of microbial genes involved in lipid production, such as the fatty acid metabolism regulator fadR. Monocolonization with a FadR-overexpressing Escherichia coli exacerbated the metabolic phenotypes, suggesting that the change in bacterial lipid metabolism is causally involved in disease progression. Mechanistically, the microbe-derived fatty acids impaired intestinal epithelial integrity to promote metabolic endotoxemia. Our study thus provides a mechanistic linkage between gut commensals and obesity through the overproduction of microbe-derived lipids.

Assessment of metagenomic workflows using a newly constructed human gut microbiome mock community.

To quantify the biases introduced during human gut microbiome studies, analyzing an artificial mock community as the reference microbiome is indispensable. However, there are still limited resources for a mock community which well represents the human gut microbiome. Here, we constructed a novel mock community comprising the type strains of 18 major bacterial species in the human gut and assessed the influence of experimental and bioinformatics procedures on the 16S rRNA gene and shotgun metagenomic sequencing. We found that DNA extraction methods greatly affected the DNA yields and taxonomic composition of sequenced reads, and that some of the commonly used primers for 16S rRNA genes were prone to underestimate the abundance of some gut commensal taxa such as Erysipelotrichia, Verrucomicrobiota and Methanobacteriota. Binning of the assembled contigs of shotgun metagenomic sequences by MetaBAT2 produced phylogenetically consistent, less-contaminated bins with varied completeness. The ensemble approach of multiple binning tools by MetaWRAP can improve completeness but sometimes increases the contamination rate. Our benchmark study provides an important foundation for the interpretation of human gut microbiome data by providing means for standardization among gut microbiome data obtained with different methodologies and will facilitate further development of analytical methods.

Estimation of silent phenotypes of calf antibiotic dysbiosis.

Reducing antibiotic usage among livestock animals to prevent antimicrobial resistance has become an urgent issue worldwide. This study evaluated the effects of administering chlortetracycline (CTC), a versatile antibacterial agent, on the performance, blood components, fecal microbiota, and organic acid concentrations of calves. Japanese Black calves were fed with milk replacers containing CTC at 10 g/kg (CON group) or 0 g/kg (EXP group). Growth performance was not affected by CTC administration. However, CTC administration altered the correlation between fecal organic acids and bacterial genera. Machine learning (ML) methods such as association analysis, linear discriminant analysis, and energy landscape analysis revealed that CTC administration affected populations of various types of fecal bacteria. Interestingly, the abundance of several methane-producing bacteria at 60 days of age was high in the CON group, and the abundance of Lachnospiraceae, a butyrate-producing bacterium, was high in the EXP group. Furthermore, statistical causal inference based on ML data estimated that CTC treatment affected the entire intestinal environment, potentially suppressing butyrate production, which may be attributed to methanogens in feces. Thus, these observations highlight the multiple harmful impacts of antibiotics on the intestinal health of calves and the potential production of greenhouse gases by calves.

An agroecological structure model of compost-soil-plant interactions for sustainable organic farming.

Compost is used worldwide as a soil conditioner for crops, but its functions have still been explored. Here, the omics profiles of carrots were investigated, as a root vegetable plant model, in a field amended with compost fermented with thermophilic Bacillaceae for growth and quality indices. Exposure to compost significantly increased the productivity, antioxidant activity, color, and taste of the carrot root and altered the soil bacterial composition with the levels of characteristic metabolites of the leaf, root, and soil. Based on the data, structural equation modeling (SEM) estimated that amino acids, antioxidant activity, flavonoids and/or carotenoids in plants were optimally linked by exposure to compost. The SEM of the soil estimated that the genus Paenibacillus and nitrogen compounds were optimally involved during exposure. These estimates did not show a contradiction between the whole genomic analysis of compost-derived Paenibacillus isolates and the bioactivity data, inferring the presence of a complex cascade of plant growth-promoting effects and modulation of the nitrogen cycle by the compost itself. These observations have provided information on the qualitative indicators of compost in complex soil-plant interactions and offer a new perspective for chemically independent sustainable agriculture through the efficient use of natural nitrogen.

The epithelia-specific membrane trafficking factor AP-1B controls gut immune homeostasis in mice.

BACKGROUND & AIMS: Epithelial cells that cover the intestinal mucosal surface maintain immune homeostasis and tolerance in the gastrointestinal tract. However, little is known about the molecular mechanisms that regulate epithelial immune functions. Epithelial cells are distinct in that they are highly polarized; this polarity is, at least in part, established by the epithelium-specific polarized sorting factor adaptor protein (AP)-1B. We investigated the role of AP-1B-mediated protein sorting in the maintenance of gastrointestinal immune homeostasis. METHODS: The role of AP-1B in intestinal immunity was examined in AP-1B-deficient mice (Ap1m2(-/-)) by monitoring their phenotypes, intestinal morphology, and epithelial barrier functions. AP-1B-mediated protein sorting was examined in polarized epithelial cells from AP-1B knockdown and Ap1m2(-/-) mice. RESULTS: Ap1m2(-/-) mice developed spontaneous chronic colitis, characterized by accumulation of interleukin-17A-producing, T-helper 17 cells. Deficiency of AP-1B caused epithelial immune dysfunction, such as reduced expression of antimicrobial proteins and impaired secretion of immunoglobulin A. These defects promoted intestinal dysbiosis and increased bacterial translocation within the mucosa. Importantly, AP-1B deficiency led to mistargeting of a subset of basolateral cytokine receptors to the apical plasma membrane in a polarized epithelial cell line and in colonic epithelial cells from mice. AP1M2 expression was reduced significantly in colonic epithelium samples from patients with Crohn's disease. CONCLUSIONS: AP-1B is required for proper localization of a subset of cytokine receptors in polarized epithelial cells, which allows them to respond to cytokine signals from underlying lamina propria cells. The AP-1B-mediated protein sorting machinery is required for maintenance of immune homeostasis and prevention of excessive inflammation.

A Japanese Herbal Formula, Daikenchuto, Alleviates Experimental Colitis by Reshaping Microbial Profiles and Enhancing Group 3 Innate Lymphoid Cells.

Daikenchuto (DKT) is one of the most widely used Japanese herbal formulae for various gastrointestinal disorders. It consists of Zanthoxylum Fructus (Japanese pepper), Zingiberis Siccatum Rhizoma (processed ginger), Ginseng radix, and maltose powder. However, the use of DKT in clinical settings is still controversial due to the limited molecular evidence and largely unknown therapeutic effects. Here, we investigated the anti-inflammatory actions of DKT in the dextran sodium sulfate (DSS)-induced colitis model in mice. We observed that DKT remarkably attenuated the severity of experimental colitis while maintaining the members of the symbiotic microbiota such as family Lactobacillaceae and increasing levels of propionate, an immunomodulatory microbial metabolite, in the colon. DKT also protected colonic epithelial integrity by upregulating the fucosyltransferase gene Fut2 and the antimicrobial peptide gene Reg3g. More remarkably, DKT restored the reduced colonic group 3 innate lymphoid cells (ILC3s), mainly RORγthigh-ILC3s, in DSS-induced colitis. We further demonstrated that ILC3-deficient mice showed increased mortality during experimental colitis, suggesting that ILC3s play a protective function on colonic inflammation. These findings demonstrate that DKT possesses anti-inflammatory activity, partly via ILC3 function, to maintain the colonic microenvironment. Our study also provides insights into the molecular basis of herbal medicine effects, promotes more profound mechanistic studies towards herbal formulae and contributes to future drug development.

Impact of dietary fructooligosaccharides (FOS) on murine gut microbiota and intestinal IgA secretion.

Fructooligosaccharides (FOS) are considered as prebiotics and are well known for their health-promoting properties, including antitumor, allergy-preventive, and infection-protective effects. They exert these effects by modulating the gut microbial composition and dynamics. In the present study, we performed a comparative whole metagenome shotgun sequencing analysis (WMGS) to elucidate the gut microbiota and secretary Immunoglobulin A (SIgA) dynamics as a result of 5% (w/w) FOS supplementation over a period of 7 days (fecal samples were collected every day). A number of taxa including Bacteroides, Lactobacillus, Roseburia, Clostridia, Faecalibaculum, and Enterorhabdus were found to be modulated with SIgA production in the murine gut. The process of SIgA production from FOS metabolization was found to be carried out via the production of short-chain fatty acids in the gut. Species of Bacteroides and Roseburia; namely, B. caccae, B. finegoldii, B. ovatus, B. thetaiotamicron, and Roseburia intestinalis, respectively, are predominantly responsible for FOS metabolization in the murine gut. The abundances of these bacterial species and their corresponding functions involved in FOS metabolization decreased over time even though these prebiotics were administered continuously for seven days. This suggests that there is a decrease in FOS metabolization over time. In addition, the present analysis suggests that the administration of FOS may help to reduce the pathogenic bacteria from the gut via SIgA production. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-022-03116-3.