Synergistic lethality between auranofin-induced oxidative DNA damage and ATR inhibition in cancer cells.

AIMS: Studies in the past have shown that inhibition of the ataxia telangiectasia and Rad3-related (ATR) kinase sensitizes cancer cells to genotoxic anticancer treatments, however, clinical use of ATR inhibitors in combination with DNA damaging chemotherapy is limited due to toxicity in healthy tissues. In this study, we investigated the synergistic anticancer effect between ATR inhibition and oxidative DNA damage induced by the thioredoxin reductase inhibitor auranofin. MAIN METHODS: Cytotoxicity was evaluated by cell viability assays. Western blot, comet assay, immunostaining and flow cytometry were performed to dissect the underlying mechanisms. In vivo efficacy was examined against tumor xenografts. KEY FINDINGS: Nontoxic doses of auranofin alone increased the levels of reactive oxygen species (ROS) in cancer but not noncancerous cells, resulting in oxidative DNA damage and activation of the ATR DNA damage response pathway selectively in cancer cells. Inhibition of ATR in auranofin-treated cancer cells resulted in unscheduled firing of dormant DNA replication origins, abrogation of the S phase cell cycle checkpoint and extensive DNA breakage, leading to replication catastrophe and potent synergistic lethality. Both the antioxidant NAC and the DNA polymerase inhibitor aphidicolin reduced replication stress and synergistic cytotoxicity, implicating replication stress-driven catastrophic cell death resulted from collision between oxidative DNA damage and dysregulated DNA replication. In vivo, auranofin and VE822 coadministration enabled marked regressions of tumor xenografts, while each drug alone had no effect. SIGNIFICANCE: As increased generation of ROS is a universal feature of tumors, our findings may open new routes to broaden the therapeutic potential of ATR inhibitors.

Maternal supplementation with Limosilactobacillus reuteri FN041 for preventing infants with atopic dermatitis: study protocol for a randomized controlled trial.

Background: Atopic dermatitis (AD) has increased rapidly with rapid urbanization; however, the treatment options for AD are lacking because the commonly used therapies can only alleviate symptoms. Limosilactobacillus reuteri (L. reuteri), FN041 is a specific strain isolated from human breast milk, and its protective potential against AD has been confirmed. This study aims to assess the efficacy of maternal consumption of L. reuteri FN041 during late pregnancy and lactation in preventing infantile AD. Methods: First, a randomized, double-blind, placebo-controlled intervention study will be conducted on 340 pregnant females with babies at high risk for AD. These subjects will be randomly divided into four groups of different doses of L. reuteri FN041 (1 × 109, 5 × 109, and 1 × 1010 CFU/d) along with a placebo. The safety and efficacy of maternal use of L. reuteri FN041 for preventing infantile AD will be analyzed, and the most efficient dosage of L. reuteri FN041 will be determined. Subsequently, a multicenter cohort study of 500 pregnant females with babies at high risk for AD will be conducted to promote the maternal application of L. reuteri FN041. These subjects will be administered L. reuteri FN041 at the optimal dose determined during the first stage of late pregnancy and lactation, and their babies will be analyzed for AD development. Recruitment was initiated in October 2022. Discussion: The primary outcome is the cumulative incidence of AD at 24 months after maternal consumption of L. reuteri FN041 during late pregnancy and lactation, whereas the secondary outcome is the efficiency of L. reuteri FN041 transfer from the mother's gut to breast milk and then the infant's gut after oral supplementation. This study will demonstrate the efficacy of edible probiotics isolated from breast milk in preventing or treating AD in infants. Accordingly, we provide population-based advice for administering specific probiotics for the primary prevention of AD in pregnant females. Understanding the underlying mechanisms of probiotic strains derived from breast milk can promote their application in preventing infant diseases associated with intestinal microbiota imbalance and immune disorders. Clinical trial registration: https://www.chictr.org.cn/, identifier [ChiCTR2300075611].

Lacticaseibacillus casei ATCC334 Ameliorates Radiation-Induced Intestinal Injury in Rats by Targeting Microbes and Metabolites.

SCOPE: Gastrointestinal side effects are frequently observed in patients receiving medical radiation therapy. As Lacticaseibacillus casei ATCC334 potentially affects microbial ecosystem, the study hypothesizes that it may improve radiation-induced intestinal injury in rats by modulating the "gut microbiota-metabolite-barrier axis." METHODS AND RESULTS: Rats are fed one of three or no doses of L. casei ATCC334 for 7 days and then expose to a single dose of 9 Gy X-ray total abdominal irradiation. Supplementation with L. casei ATCC334 promote the proliferation of intestinal stem cells (ISCs), increase the expression of tight junction proteins, reduce intestinal permeability, and protect intestinal barrier integrity. Moreover, 16S rRNA sequencing show that medium and high doses of L. casei ATCC334 inhibit the growth of Escherichia/Shigella and favor Akkermansia proliferation. L. casei ATCC334 intervention reprogram the metabolic profile and inhibit putrescine production but promote alpha-linolenic acid (ALA) production. Notably, a decrease in putrescine and an increase in ALA are significantly correlated with the proliferation of ISCs and enhanced intestinal barrier function following L. casei ATCC334 intervention. CONCLUSION: These results highlight that medium and high doses of L. casei ATCC334 alleviate radiation-induced intestinal damage by enhancing the mucosal barrier and remodeling the gut microbiota structure and metabolic activity.

Breast Milk-Derived Limosilactobacillus reuteri Prevents Atopic Dermatitis in Mice via Activating Retinol Absorption and Metabolism in Peyer's Patches.

SCOPE: Supplementing Limosilactobacillus reuteri Fn041, a breast milk-derived probiotic from agricultural and pastoral areas, to maternal mice during late pregnancy and lactation prevents atopic dermatitis (AD) in offspring. This study aims to elucidate the molecular mechanism of Fn041-mediated immune regulation. METHODS AND RESULTS: Fn041 is administered prenatal and postnatal to maternal mice, and to offspring after weaning. The ears are administered with calcipotriol to induce AD. Fn041 treatment significantly alleviates ear inflammation, and reduces mast cell infiltration. Fn041 treatment upregulates and downregulates intestinal ZO-1 and Claudin-2 mRNA expression, respectively. Transcriptome analysis of Peyer's patches reveals that pathways related to DNA damage repair are activated in AD mice, which is inhibited by Fn041 treatment. Fn041 activates pathways related to retinol absorption and metabolism. Untargeted metabolomic analysis reveals that Fn041 treatment increases plasma retinol and kynurenine. Fn041 treatment does not significantly alter the overall cecal microbiota profile, only increases the relative abundances of Ligilactobacillus apodemi, Ligilactobacillus murinus, Akkermansia muciniphila, and Bacteroides thetaiotaomicron. CONCLUSIONS: Fn041 induces anti-AD immune responses directly by promoting the absorption and metabolism of retinol in Peyer's patches, and plays an indirect role by strengthening the mucosal barrier and increasing the abundance of specific anti-AD bacteria in the cecum.

Limosilactobacillus reuteri FN041 prevents atopic dermatitis in pup mice by remodeling the ileal microbiota and regulating gene expression in Peyer's patches after vertical transmission.

Objectives: Limosilactobacillus reuteri FN041 is a potential probiotic bacterium isolated from breast milk in traditional farming and pastoral areas of China. The purpose of this study was to investigate the optimal intervention mode and potential mechanism of FN041 to prevent atopic dermatitis (AD) in mice. Methods: In intervention mode I, FN041 was supplemented to dams during the late trimester and lactation and pups after weaning; in intervention mode II, FN041 was supplemented after pups were weaned. AD was induced in pups with MC903 plus ovalbumin on the ear after weaning. Results: The effect of intervention mode I in preventing AD was significantly better than that of intervention mode II. Compared with the model group, the inflammatory response of the pup's ears, the proportion of spleen regulatory T cells and the plasma IgE were significantly decreased in mice in intervention mode I. Furthermore, the intestinal mucosal barrier was enhanced, and the Shannon index of the ileal microbiota was significantly increased. The microbiota structure deviated from the AD controls and shifted toward the healthy controls according to the PCoA of unweighted UniFrac. The relative abundances of Limosilactobacillus, Faecalibacterium, Bifidobacterium, and Akkermansia in the ileum were significantly increased compared to the AD group. Based on RNA-seq analysis of pups' Peyer's patches (PPs), FN041 inhibits autoimmune pathways such as asthma and systemic lupus erythematosus and activates retinol metabolism and PPAR signaling pathways to reduce inflammatory responses. Intervention mode II also significantly reduced AD severity score, but the reduction was approximately 67% of that of intervention mode I. This may be related to its ineffective remodeling of the ileal microbiota. Conclusion: Prenatal and postnatal administration of FN041 is an effective way to prevent AD in offspring, and its mechanism is related to remodeling of ileal microbiota and PPs immune response.

Widespread vertical transmission of secretory immunoglobulin A coated trace bacterial variants from the mother to infant gut through breastfeeding.

Gut microbiota transmission from mother to offspring is critical to infant gut microbiota and immune development. Mother's intestine and breast milk are rich in secretory immunoglobulin A (sIgA), which can coat a specific bacterial spectrum and may be related to bacterial transmission and colonization. Here we analyzed the microbiota and sIgA-coated bacteria of maternal fecal samples and breast milk and infant fecal samples from 19 dyads by 16S rRNA amplicon sequencing. For the sIgA-coated microbiota, both the phylogenetic diversity and the Shannon index of maternal fecal samples show a lower trend than those of infant fecal samples (P < 0.05). For beta diversity, all three samples were significantly different from each other (P < 0.05, based on permutational multivariate analysis of variance). We found that sIgA mediated a wide range of vertical transmission of trace bacteria with a relative abundance of amplicon sequence variants of more than 0.0001%. FEAST-based analysis reveals that there was an equal contribution of the maternal gut (median [IQR]; 8.75% [0.90, 62.14]) and breast milk (9.23% [1.69, 22.29]) to infant intestinal total microbiota. The 39 percent of sIgA-coated microbiota in breast milk samples provided as much as 28.49-93.84 percent of all sIgA-coated microbiota in the newborn gut. Therefore, maternal gut and breast milk sIgA-coated bacteria are essential sources of intestinal bacteria in infants. There was high individual variation in the contribution of the maternal gut and breast milk microbiota to the paired infant gut microbiota. Analysis based on the weighted transfer ratio (WTR) explained that diverse sIgA-coated bacteria are transferred from breast milk to the gut of the respective infant, mainly lactic acid bacteria, especially Lactobacillus gasseri (WTR = 2475.5), Enterococcus faecium (WTR = 2438) and Streptococcus salivarius (WTR = 117.71). Bifidobacterium longum, with a WTR of 69.35, is the key sIgA-coated bacteria that are transferred from the mother's gut to breast milk. In conclusion, sIgA mediates the vertical transmission of specific bacteria, to realize the controllable inheritance of the intestinal bacteria and function from the mother to the offspring. This provides a new basis for the screening of probiotics for infant formula addition.

Mixed nuts with high nutrient density improve insulin resistance in mice by gut microbiota remodeling.

The consumption of mixed nuts is a healthy dietary strategy to reduce the risk of cardiovascular disease and has a prebiotic effect on the gut microbiota. However, there is a lack of basic research based on mixed nut formulation. This study established a new method for optimizing mixed nut formulations using the Nutrient Rich Food (NRF) index model. Nutrient indices were adjusted by combining 10 and 8 encouraging nutrients and 3 limiting nutrients of nuts and dried fruits, respectively. The optimized mixed nut formulation had the highest total NRF and the lowest energy, which was achieved by applying linear programming. The effect of an optimized mixed nut formulation on insulin resistance and gut microbiota was investigated in an animal model of metabolic disorders caused by a high-fat diet. Male C57BL/6J mice (n = 12 per group) were fed a low-fat diet, a high-fat diet (HFD), HFD with a supplemented classical randomized controlled trial mixed nut formula (MN1), a commercially available mixed nut formula (MN2), a high-nutrient density mixed nut formula (MN3), or ellagic acid (positive control). MN3 treatment decreased total plasma cholesterol, homeostasis model assessment-insulin resistance index, high sensitivity C-reactive protein, and zonulin levels, strengthened the intestinal barrier, and significantly altered the ß-diversity of the intestinal microbiota as compared to the HFD group. These effects of MN3 were superior to MN1 and MN2. In conclusion, MN3 had the highest nutrient density and improved insulin resistance in low-grade inflammation via gut microbiota remodeling.

The Antidepressant Effect of Deoiled Sunflower Seeds on Chronic Unpredictable Mild Stress in Mice Through Regulation of Microbiota-Gut-Brain Axis.

Objectives: Sunflower seeds provide tryptophan-rich proteins with the potential to protect against depression. Tryptophan is a precursor of serotonin and a substrate for the production of indole derivatives by gut microbiota. This study aimed to investigate the association between the depression-alleviating effects of deoiled and dechlorogenic sunflower seeds (DSFS) and regulation of gut microbiota. Materials and Methods: Male C57BL/6J mice were fed a diet comprising a source of soy protein (normal and model control), DSFS or whey protein concentrate (positive control) for 7 weeks, and chronic stress-induced depression was induced. Results: Feeding the DSFS diet prevented depression-like behaviors, intestinal barrier damage, elevated plasma corticosterone, and reduced hippocampal serotonin levels in mice. Meanwhile, Feeding the DSFS diet significantly altered the gut microbiota structure, characterized by elevated relative abundances of Ileibacterium valens, Ruminococcus flavefaciens, Clostridium scindens, and Olsenella massiliensis, which were inversely associated with depressive behaviors and markers of mucosal barrier damage. DSFS also altered the gut metabolite profile, prevented depression-induced gut L-tryptophan depletion, and upregulated its metabolite indoleacetaldehyde. Conclusion: Feeding the DSFS diet prevented depression in mice by remodeling the gut microbiota and bacterial tryptophan metabolism.

Prevention of High-Fat Diet-Induced Hypercholesterolemia by Lactobacillus reuteri Fn041 Through Promoting Cholesterol and Bile Salt Excretion and Intestinal Mucosal Barrier Functions.

Objectives: Lactobacillus reuteri Fn041 (Fn041) is a probiotic isolated from immunoglobulin A coated microbiota in the human breast milk of Gannan in China with a low incidence of hypercholesterolemia. This study aims to explore the role and mechanism of Fn041 in preventing hypercholesterolemia caused by a high-fat diet in mice. Methods: C57BL/6N mice were fed a low-fat diet or a high-fat diet and gavage with Fn041 and Lactobacillus rhamnosus GG (LGG) for 8 weeks. Results: Both Fn041 and LGG prevented the occurrence of hypercholesterolemia, liver and testicular fat accumulation. In addition, a high-fat diet causes intestinal dysbiosis and mucosal barrier damage, which is associated with hypercholesterolemia. Fn041 prevented the high-fat diet-induced reduction in alpha diversity of intestinal microbiota and intestinal mucosal barrier damage. Fn041 treatment significantly increased fecal total cholesterol and total bile acids. Conclusions: Fn041 prevented hypercholesterolemia by enhancing cholesterol excretion and mucosal barrier function.

Prevention of Atopic Dermatitis in Mice by Lactobacillus Reuteri Fn041 Through Induction of Regulatory T Cells and Modulation of the Gut Microbiota.

SCOPE: The development of atopic dermatitis (AD) in infants is closely related to the lagging development of intestinal microbiota, including that inoculated by breast milk bacteria, and immune development. Lactobacillus reuteri Fn041 is a secretory immunoglobulin A (sIgA) -coated bacterium derived from human milk. METHODS AND RESULTS: We intervene with L. reuteri Fn041 in maternal and offspring BALB/C mice during late gestation and lactation and after weaning of the pups, respectively. AD is then induced with MC903. L. reuteri Fn041 significantly suppresses AD symptoms such as skin swelling, mast cell, and eosinophil infiltration. This effect is attributed to the regulation of the systemic Th1 and Th2 cytokine ratios and the promotion of CD4+ CD25+ Foxp3+ regulatory T cell proliferation in mesenteric lymph nodes. It is also associated with the regulation of intestinal microbiota, particularly promoting Lactobacillus and Akkermansia. CONCLUSION: Our study strengthens the understanding that breast milk-derived sIgA coated potential probiotics are involved in the development of infant intestinal microbiota, thus promoting immune development and preventing allergic diseases, and expanding the knowledge of breast milk sIgA and bacterial interactions on infant immune development.

Lactation-dependent vertical transmission of natural probiotics from the mother to the infant gut through breast milk.

The transmission of certain bacteria from the mother's gut to the infant's gut via breast milk (BM) is critical for the offspring's immune system development. Dysbiosis of the BM microbiota can be caused by a variety of reasons, which can be influenced by probiotics delivered via the enteromammary route. The goal of this study was to investigate the bacteria that can be transmitted from the mother to the infant's intestine during various lactation periods in 19 mother-child dyads. Bacterial transmission is most common during the colostrum phase when bacteria with certain amplicon sequence variants (ASVs) enter the newborn intestine and inhabit it permanently. We have established that anaerobic gut-associated bacteria, such as Faecalibacterium, Blautia and Lachnoclostridium, transfer from the mother to the infant's gut with lactation dependence using the idea of weighted transfer ratios. Streptococcus salivarius, Bifidobacterium longum, and Lactobacillus gasseri are transferred from the maternal gut to the BM, as well as from the BM to the newborn gut, depending on different ASVs. These findings suggest that isolation of key microorganisms from breast milk could be utilized to modify the microbiota of BM or newborns by giving the mother a probiotic or adding it to artificial milk to promote neonatal health.

Gastrointestinal biotransformation and tissue distribution of pterostilbene after long-term dietary administration in mice.

The metabolic fate of dietary compounds is closely related to their biological functions. Pterostilbene (PT) is a methylated stilbene found in many plant foods. Herein, we investigated gastrointestinal biotransformation and tissue distribution of PT in mice fed with 0.05% PT (w/w) for 5 weeks. PT and its major metabolites i.e. PT sulfate (PT-S), pinostilbene, pinostilbene sulfate, hydroxylated PT and hydroxylated PT sulfate were identified and quantified in the mucosa and content of the digestive tissues, blood, urine and vital organs. The results showed PT underwent demethylation, hydroxylation and conjugation in the small intestine, while the conjugated metabolites were largely deconjugated in the colon. Anaerobic fermentation with mouse cecal bacteria demonstrated the microbiota mediated deconjugation and demethylation of PT-S and PT, respectively. In conclusion, oral consumption of PT led to extensive biotransformation in mouse gastrointestinal tract and the metabolites of PT might play important roles in the bioactivity of PT.

Depletion of gut secretory immunoglobulin A coated Lactobacillus reuteri is associated with gestational diabetes mellitus-related intestinal mucosal barrier damage.

Changes in secretory immunoglobulin A (SIgA) coated bacteria from early to late pregnancy were associated with the development of gestational diabetes mellitus (GDM). SIgA coated beneficial gut bacteria, which are depleted in GDM, are potential probiotics for the prevention of GDM. We investigated blood biochemistry, chronic inflammation, mucosal barrier biomarkers and faecal SIgA coated microbiota in healthy early pregnancy (T1H, n = 50), late pregnancy (T3H, n = 30) and women with GDM (T3D, n = 27). The "leaky gut" markers, zonulin and lipopolysaccharide (LPS), significantly increased in T3D compared to the T3H group. The Shannon index of SIgA coated microbiota was elevated in late pregnancy compared to early pregnancy and was the highest in the T3D group (p < 0.001). The T3D group was enriched in SIgA coated Escherichia and Streptococcus and depleted in Lactobacillus and Bifidobacterium. Blood glucose (BG) positively correlated with zonulin (p < 0.001) and LPS (p < 0.05). Lactobacillus reuteri negatively correlated with BG (p < 0.05), zonulin (p < 0.05) and LPS (p < 0.01). Lactobacillus reuteri QS01 isolated from the feces of T1H significantly reduced LPS released by the gut microbiota of GDM individuals in vitro. In conclusion, GDM may be related to intestinal mucosal damage and inflammation-induced dysbiosis of SIgA coated microbiota. SIgA coated L. reuteri can reduce the level of LPS of GDM in vitro.

Sex-dependent modulation of immune development in mice by secretory IgA-coated Lactobacillus reuteri isolated from breast milk.

Lactobacilli, commonly present in human breast milk, appear to colonize the neonatal gut and provide protection to infants against various infections, thereby promoting immune development. This study examined the potential probiotic role of breast milk-derived Lactobacillus reuteri FN041 in immune development in mice. The FN041 were gavaged either to BALB/c dams (n = 6/group) during the lactation period or to their offspring (n = 6/sex per intervention) after weaning separately (cointervention). All interventions induced increased intestinal barriers in 5-wk-old offspring, especially in the females. Immunoglobulin A plasmocytes in ileal tissue and secretory IgA (sIgA) in ileal contents increased in all 5-wk-old offspring of cointervention. The activation of mRNA expression of 17 genes was sex-dependent, especially in 5-wk-old offspring. Broader genes were regulated in female mice. The effect of cointervention on the Shannon index of total microbiota is sex-related. The Shannon index of sIgA-coated microbiota increased in both sexes. The sIgA-coated microbiota showed intergroup differences according to ß diversity, especially in female mice that showed an increase in Bifidobacterium of Actinobacteria. The sIgA-coated Bifidobacterium was positively correlated with mRNA expression of Tlr9. The sIgA-coated Lactobacillus in male offspring was negatively correlated with mRNA expression of Cldn2. In conclusion, L. reuteri FN041 promoted the production of intestinal sIgA and the expression of genes related to antimicrobial peptides in the offspring and enhanced the function of the mucosal barrier, depending on sex and treatment manner.

A pregnancy complication-dependent change in SIgA-targeted microbiota during third trimester.

Gut microbiota play a crucial role in metabolic dysfunction during gestation, which might be prevented by using probiotics. This study compared the composition of the gut microbiota in healthy and complicated pregnancies, for screening and isolating healthy pregnancy-derived probiotics. According to the principal component analysis of secretory immunoglobulin A (SIgA)-coated microbiota in the gut, third-trimester volunteers can be divided into three groups: AHd (n = 29), GDMd (n = 37), and GHd (n = 25), dominated by asymptomatic healthy donors (62.07%), gestational diabetes mellitus (GDM) donors (40.54%), and gestational hypertension (GH) donors (40%), respectively. There was a significant difference in ß-diversity (p < 0.01) and α-diversity (p < 0.05) among the three groups. At the phylum level, the Firmicutes of the GHd group were significantly lower than those of the AHd group (p = 0.039), while Bacteroidetes (p = 0.005) and Proteobacteria (p = 0.002) of the GHd group were more dominant than those of the AHd group. At the genus level, the linear discriminant analysis effect size showed that SIgA-targeted Enterococcus was the dominant taxonomic biomarker of the AHd group, and the GHd group was enriched with Escherichia and Streptococcus. The GDMd and GHd groups had higher faecal calprotectin, serum lipopolysaccharide, zonulin, and GLYCAM-1 levels. We conclude that the occurrence of complications in the third trimester may be related to intestinal barrier injury associated with disorders of the intestinal SIgA-targeted microbiota; gut barrier injury triggers inflammation in pregnant women. SIgA-targeted L. reuteri showed a significant correlation with low inflammatory response and may be a potential probiotic candidate for preventing pregnancy complications.

Dietary resveratrol attenuated colitis and modulated gut microbiota in dextran sulfate sodium-treated mice.

Accumulating evidence suggests that the gut microbiota plays an important role in the pathogenesis of colitis and that its composition could be modulated by exposure to dietary components. Thus, it may be possible to ameliorate the severity of colitis through administration of dietary components. Herein, we determined the effects of orally administered resveratrol on the gut microbiota composition and the resulting inflammatory status of a dextran sodium sulfate (DSS)-induced colitis mouse model. Our results supported our hypothesis that dietary resveratrol altered the microbial composition and restored microbial community diversity in DSS-treated mice. Specifically, resveratrol effectively decreased the abundance of the genera Akkermansia, Dorea, Sutterella and Bilophila, and increased the proportion of Bifidobacterium in colitic mice. Resveratrol was also able to prevent mouse body weight loss, reduce the disease activity index, attenuate tissue damage, and down-regulate the expression of pro-inflammatory cytokines such as IL-2, IFN-γ, GM-CSF, IL-1ß, IL-6, KC/GRO, and TNF-α in the colon of DSS-treated mice. Pearson's correlation analysis indicated significant correlations between the relative levels of these pro-inflammatory cytokines and alterations of the gut microbiota. Our results demonstrated that dietary resveratrol attenuated the inflammatory status and alleviated gut microbiota dysbiosis in a colitis mouse model.

The gastrointestinal fate of limonin and its effect on gut microbiota in mice.

The gut microbiota plays a critical role in human health. Diets could modulate the gut microbiota, which in turn may contribute to altered health outcomes by way of changing the relative risk of chronic diseases. Limonin, widely found in citrus fruits, has been reported to possess multiple beneficial health effects. However, the gastrointestinal fate of limonin and its effect on gut microbiota remain unknown. Herein, mice were fed a diet containing 0.05% limonin (w/w) for 9 weeks. Liquid chromatography-mass spectrum analysis showed that limonin was concentrated along the gastrointestinal tract and reached 523.14 nmol g-1 in the colon lumen. Compared to control mice, colonic microbiota richness was significantly increased by limonin. Gut microbiota community was also clearly distinct from the control group as shown by Principle Coordinate Analysis. Additionally, the relative abundance of 22 genera (relative abundance >0.1%) was altered significantly. Among these, generally regarded probiotics (Lactobacillus and Bifidobacterium) were reduced, which was not due to direct inhibitory effect of limonin. According to the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, amino acid metabolism, lipid, metabolism and immune system function were predicted to be upregulated, and immune system disease and infectious disease markers were predicted to be suppressed dramatically by limonin based on gut microbiota composition. Within the infectious disease category, bacterial toxin and Staphylococcus aureus infection markers were suppressed significantly with limonin treatment. Collectively, our study provides the first line of evidence that oral intake of limonin could shift gut microbiota composition and its functions, which warrants further investigation to determine its implication in human health.

Lactobacillus reuteri improves gut barrier function and affects diurnal variation of the gut microbiota in mice fed a high-fat diet.

Lactobacillus reuteri FN041 is a secretory IgA-targeted Lactobacillus strain from human breast milk that has probiotic potential. The aim of this study was to test whether FN041 can alleviate dyslipidaemia and mucosal-barrier damage caused by a high-fat diet (HFD) and whether it can affect diurnal variation of the intestinal microbiota. C57BL/6 mice were fed either a normal chow diet or high-fat diet (HFD) for 7 weeks and were treated with either PBS as a control or L. reuteri FN041 for 4 weeks. Our results showed that FN041 treatment significantly attenuated HFD-induced weight gain (P < 0.01), accumulation of testicular fat, an increase in locomotor activity during the active phase (P < 0.01), triglyceridaemia, hypercholesterolaemia (P < 0.05), liver Fas overexpression, and Srebp1c mRNA expression inhibition. Moreover, FN041 treatment improved intestinal epithelial barrier function and induced a daily oscillation-dependent change in short-chain fatty acid production by the gut microbiota. A deeper understanding of the molecular pathways participating in intestinal barrier and microbiota modifications, and changes to lipid metabolism under the influence of FN041, will have important implications by potentially opening new horizons for the development of relevant foods to prevent metabolic disorders and unrelated intestinal diseases.

IgA-Targeted Lactobacillus jensenii Modulated Gut Barrier and Microbiota in High-Fat Diet-Fed Mice.

IgA-coated Lactobacillus live in the mucous layer of the human or mammalian intestine in close proximity to epithelial cells. They act as potential probiotics for functional food development, but their physiological regulation has not yet been studied. We isolated IgA-targeted (Lactobacillus jensenii IgA21) and lumen lactic acid bacterial strains (Pediococcus acidilactici FS1) from the fecal microbiota of a healthy woman. C57BL/6 mice were fed a normal (CON) or high fat diet (HFD) for 6 weeks and then treated with IgA21 or FS1 for 4 weeks. HFD caused dyslipidemia, mucosal barrier damage, and intestinal microbiota abnormalities. Only IgA21 significantly inhibited dyslipidemia and gut barrier damage. This was related to significant up-regulation of mucin-2, PIgR mRNA expression, and colonic butyrate production (P < 0.05 vs. HFD). Unlike IgA21, FS1 caused a more pronounced gut dybiosis than did HFD, and, in particular, it induced a significant decrease in the Bacteroidales S24-7 group and an increase in Desulfovibrionaceae (P < 0.05 vs. CON). In conclusion, IgA-coated and non-coated lactic acid bacteria of gut have been demonstrated to differentially affect the intestinal barrier and serum lipids. This indicates that IgA-bound bacteria possess the potential to more easily interact with the host gut to regulate homeostasis.