Dietary Isoflavones Alter Gut Microbiota and Lipopolysaccharide Biosynthesis to Reduce Inflammation

Identification of lipid metabolism-related gene markers and construction of a diagnostic model for multiple sclerosis: An integrated analysis by bioinformatics and machine learning

BACKGROUND

Multiple sclerosis (MS) is an autoimmune inflammatory disorder that causes neurological disability. Dysregulated lipid metabolism contributes to the pathogenesis of MS. This study aimed to identify lipid metabolism-related gene markers and construct a diagnostic model for MS.

METHODS

Gene expression profiles for MS were obtained from the Gene Expression Omnibus database. Differentially expressed lipid metabolism-related genes (LMRGs) were identified and performed functional enrichment analysis. Least absolute shrinkage and selection operator (LASSO), random forest (RF), and protein-protein interaction (PPI) analysis were employed to screen hub genes. The predictive power of hub genes was evaluated using receiver operating characteristic (ROC) curves. We developed an artificial neural network (ANN) model and validated its performance in three test sets. Immune cell infiltration analysis, Gene set enrichment analysis, and ceRNA network construction were performed to explore the role of lipid metabolism in the pathogenesis of MS. Drugs prediction and molecular docking were utilized to identify potential therapeutic drugs.

RESULTS

We identified 40 differentially expressed LMRGs, with significant enrichment in Arachidonic acid metabolism, Steroid hormone biosynthesis, Fatty acid elongation, and Sphingolipid metabolism. AKR1C3, NFKB1, and ABCA1 were identified as gene markers for MS, and their expression was upregulated in the MS group. The areas under the ROC curve (AUCs) for AKR1C3, NFKB1, and ABCA1 in the training set were 0.779, 0.703, and 0.726, respectively. The ANN model exhibited good discriminative ability in both the training and test sets, achieving an AUC of 0.826 on the training set and AUC values of 0.822, 0.890, and 0.833 on the test sets. Gamma.delta.T.cell, Natural.killer.T.cell, Plasmacytoid.dendritic.cell, Regulatory.T.cell, and Type.1.T.helper.cell were highly expressed in the MS group. A ceRNA network showed a complex regulatory interplay involving hub genes. Luteolin, isoflavone, and thalidomide had good binding affinities to the hub genes.

CONCLUSION

Our study emphasized the crucial role of lipid metabolism in MS, identifing AKR1C3, NFKB1, and ABCA1 as gene markers. The ANN model exhibited good performance on both the training and testing sets. These findings offer valuable insights into the molecular mechanisms underlying MS, and establish a scientific foundation for future research.

Comparative analysis of intestinal microbiota and its function on digestion and immunity of juvenile abalone Haliotis discus hannai fed two different sources of dietary soybean protein

The present study evaluated the replacement of fish meal (FM) with two different soybean protein sources (soybean protein concentrate (SPC) and soybean meal (SBM)) on the intestine microbiota of abalone Haliotis discus hannai and the implications for the host intestinal function and health. The control diet with FM as the main protein source (CON), and the four experimental diets with 50 % and 100 % SBM replacing FM (SBM50 and SBM100), and 25 % and 100 % SPC replacing FM (SPC25 and SPC100) were fed to abalone for 110 days. The intestinal microbiota analysis results revealed that there were no significant differences in α-diversity indices (Chao1, Ace, Sobs, and Shannon) among all groups. However, analysis of similarity (ANOSIM) demonstrated dramatic shifts in the intestinal microbiota component at the genus level among the groups. Venn diagram analysis identified 470 overlapping operational taxonomic units (OTUs) across the five groups, with the SBM50 and CON groups exhibiting the highest and lowest number of unique OTUs, respectively. Firmicutes and Proteobacteria were the predominant phyla in abalone, with Mycoplasma being the dominant genus (CON: 42.95 %; SBM50: 23.98 %; SBM100: 49.32 %; SPC25: 27.20 %; SPC100: 34.25 %). Notably, the pathogens Vibrio abundance in the SPC25 group was significantly lower than in the CON group. The intestinal microbiota networks in the CON, SBM50, SBM100, SPC25, and SPC100 groups consisted of 1757, 2140, 1992, 2281 and 1747 edges, respectively. Furthermore, correlation heatmap results suggested that digestive enzymes and immune indices in abalone were associated with specific intestinal microbiota. Functional prediction via the KEGG pathway analysis revealed that the replacement levels of dietary FM with SBM and SPC significantly affect various biological functions of the intestinal microbiota. In summary, feeding SBM (50 %) and SPC (25 %) diets to abalone increased the abundance of beneficial bacterium in the intestines, contributing to improved digestion and increased growth rate of abalone.

Flavonoids for gastrointestinal tract local and associated systemic effects: A review of clinical trials and future perspectives

BACKGROUND

Flavonoids are naturally occurring dietary phytochemicals with significant antioxidant effects aside from several health benefits. People often consume them in combination with other food components. Compiling data establishes a link between bioactive flavonoids and prevention of several diseases in animal models, including cardiovascular diseases, diabetes, gut dysbiosis, and metabolic dysfunction-associated steatotic liver disease (MASLD). However, numerous clinical studies have demonstrated the ineffectiveness of flavonoids contradicting rodent models, thereby challenging the validity of using flavonoids as dietary supplements.

AIM OF REVIEW

This review provides a clinical perspective to emphasize the effective roles of dietary flavonoids as well as to summarize their specific mechanisms in animals briefly.

KEY SCIENTIFIC CONCEPTS OF REVIEW

First, this review offers an in-depth elucidation of the metabolic processes of flavonoids within human, encompassing the small, large intestine, and the liver. Furthermore, the review provides a comprehensive overview of the various functions of flavonoids in the gastrointestinal tract, including hindering the breakdown and assimilation of macronutrients, such as polysaccharides and lipids, regulating gut hormone secretion as well as inhibition of mineral iron absorption. In the large intestine, an unabsorbed major portion of flavonoids interact with the gut flora leading to their biotransformation. Once absorbed and circulated in the bloodstream, bioactive flavonoids or their metabolites exert numerous beneficial systemic effects. Lastly, we examine the protective effects of flavonoids in several metabolic disorders, including endothelial dysfunction, MASLD, cardiovascular disease, obesity, hyperlipidemia, and insulin resistance. In conclusion, this review outlines the safety and future prospects of flavonoids in the field of health, especially in the prevention of metabolic syndrome (MetS).

Soy protein β-conglycinin ameliorates pressure overload-induced heart failure by increasing short-chain fatty acid (SCFA)-producing gut microbiota and intestinal SCFAs

BACKGROUND AND AIMS

Soybeans and their ingredients have antioxidant and anti-inflammatory effects on cardiovascular diseases. β-Conglycinin (β-CG), a major constituent of soy proteins, is protective against obesity, hypertension, and chronic kidney disease, but its effects on heart failure remain to be elucidated. We tested the effects of β-CG on left ventricular (LV) remodeling in pressure overload-induced heart failure.

METHODS

A transverse aortic constriction (TAC)-induced pressure overload was applied to the heart in 7-week-old C57BL6 male mice that were treated with β-CG, GlcNAc, or sodium propionate. Gut microbiota was analyzed by 16S rRNA sequencing. Fecal short-chain fatty acids (SCFAs) were quantified by GC-MS. The effects of oral antibiotics were examined in β-CG-fed mice.

RESULTS

β-CG ameliorated impaired cardiac contractions, cardiac hypertrophy, and myocardial fibrosis in TAC-operated mice. As β-CG is a highly glycosylated protein, we examined the effects of GlcNAc. GlcNAc had similar but less efficient effects on LV remodeling compared to β-CG. β-CG increased three major SCFA-producing intestinal bacteria, as well as fecal concentrations of SCFAs, in sham- and TAC-operated mice. Oral administration of antibiotics nullified the effects of β-CG in TAC-operated mice by markedly reducing SCFA-producing intestinal bacteria and fecal SCFAs. In contrast, oral administration of sodium propionate, one of SCFAs, ameliorated LV remodeling in TAC-operated mice to a similar extent as β-CG.

CONCLUSIONS

β-CG was protective against TAC-induced LV remodeling, which was likely to be mediated by increased SCFA-producing gut microbiota and increased intestinal SCFAs. Modified β-CG and/or derivatives arising from β-CG are expected to be developed as prophylactic and/or therapeutic agents to ameliorate devastating symptoms in heart failure.

Progress in the preparation, structure and bio-functionality of Dictyophora indusiata polysaccharides: A review

Dictyophora indusiata (D. indusiata) is an elegant fungus known as the "mushroom queen" because of its rich nutritional value and resemblance to dancers wearing clean white dresses. Due to the harsh growth environment, the yield of D. indusiata is relatively low. Polysaccharides are the most abundant component among them and it is valued for its unique physiological function. Multiple extraction and purification methods have been used to separate and purify polysaccharides from D. indusiata. These polysaccharides have demonstrated strong biological activities in vitro and in vivo, including anti-inflammatory, anti-tumour, immunomodulatory, antioxidant and anti-hyperlipidemic effects. In addition, D. indusiata polysaccharides have shown promising potential for development and application in the areas of food, healthcare products, pharmaceuticals, and cosmetics. Recent advances in the extraction, purification, structural characterization, biological activities and application prospects of D. indusiata polysaccharides were summarized. This review may enrich the knowledge about bioactive polysaccharides from D. indusiata and provide a theoretical basis. Due to diverse potential health-promoting properties of D. indusiata polysaccharides, further development for their application in functional foods and pharmaceuticals is expected.

Dietary soy protein reverses obesity-induced liver steatosis and alters fecal microbial composition independent of isoflavone level

Introduction

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a major public health concern that is exacerbated by the obesity pandemic. Dietary interventions have the potential to alleviate obesity-associated MASLD through variable mechanisms, including optimizing the gut microbiota. Previously, we reported that soy protein concentrate (SPC) with low or high levels of isoflavone (LIF or HIF) protected young obese Zucker rats from developing liver steatosis. The current study was designed to test whether SPC-LIF and SPC-HIF diets would reverse liver steatosis and alter fecal microbial composition in adult obese Zucker rats with existing steatosis.

Methods

Six-week-old male obese Zucker rats (n = 26) were fed a casein control diet (CAS) for 8 weeks and 7 rats were randomly selected and sacrificed to confirm liver steatosis. The remaining rats were randomly assigned to receive CAS, SPC-LIF, or SPC-HIF diet (n = 6-7/group) for an additional 10 weeks.

Results

Compared to CAS diet, feeding SPC-LIF and SPC-HIF diets resulted in significantly lower liver weight, liver steatosis score, and liver microvesicular score (p < 0.05), but did not lead to difference in body weight, liver macrovesicular score, serum ALT, or serum AST. Isoflavone levels (e.g., LIF vs. HIF) did not affect any of these measurements except in the SPC-HIF group, which had an additional decrease in liver weight (p < 0.05) compared to the SPC-LIF group. The SPC-HIF group also had significantly higher levels of the aglycone forms of daidzein, genistein, and equol as well as the total levels of daidzein, genistein, and equol compared to SPC-LIF or CAS diet fed rats (p < 0.05). The distribution of microbial communities based on measures of beta diversity of both SPC-LIF and SPC-HIF groups were significantly different to that of the CAS group (p ≤ 0.005). Alpha-diversity did not differ between any of the groups.

Conclusion

Taken together, dietary soy protein can reverse liver steatosis in adult Zucker rats, and the reversal of steatosis is accompanied by alterations in gut microbial composition.

Soymilk yogurt fermented using Pediococcus pentosaceus TOKAI 759 m improves mice gut microbiota and reduces pro-inflammatory cytokine production

This study aimed to determine the anti-inflammatory activities and bioactive compounds of soymilk yogurt prepared using Lactiplantibacillus plantarum TOKAI 17 or Pediococcus pentosaceus TOKAI 759 m. Mice were divided into five groups: normal diet (ND), soymilk, soymilk yogurt using L. plantarum TOKAI 17 (SY 17) or P. pentosaceus TOKAI 759 m (SY 759 m), and 0.5 × 109 cells of each starter strain (BC 17 or BC759m). In the SY 759 m group, the serum pro-inflammatory cytokine levels and the cytotoxicity of natural killer cells were attenuated compared to the ND group. In the cecum microbiota, the abundances of butyrate-producing bacteria increased in the SY 759 m and BC 17 groups. Furthermore, SY 759 m metabolites contained high levels of aglycone isoflavone, adenine and showed a significant decrease in CCL-2 and interleukin-6 production in lipopolysaccharide-induced macrophage. In conclusion, soymilk yogurt produced using P. pentosaceus TOKAI 759 m modulates the gut microbiota and can potentially prevent pro-inflammatory cytokine production.

Investigating the regulatory effect of Shen Qi Bu Qi powder on the gastrointestinal flora and serum metabolites in calves

Object

To investigate the effects of Shen Qi Bu Qi Powder (SQBQP) on the average daily gain, blood indexes, gastrointestinal microflora, and serum metabolites of calves.

Methods

A total of 105 calves were randomly assigned to three groups (n = 35 per group): the control group (C, fed with a basal diet for 21 days) and two treatment groups (SQBQP-L and SQBQP-H, fed with the basal diet supplemented with 15 and 30 g/kg of SQBQP), respectively for 21 days. The active components of SQBQP were identified using LC-MS/MS. Serum digestive enzymes and antioxidant indices were determined by ELISA kits and biochemical kits, respectively. Serum differential metabolites were analyzed by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS), while flora in rumen fluid and fecal were analyzed by 16S rDNA sequencing. Further correlation analysis of gastrointestinal flora and serum metabolites of SQBQP-H and C groups were performed with Spearman's correlation.

Results

The principal active components of SQBQP mainly includes polysaccharides, flavonoids, and organic acids. Compared to the control group (C), calves in the SQBQP-H (high dose) and SQBQP-L (low dose) groups showed a significant increase in serum amylase (AMS) levels (P<0.001), while lipase content significantly decreased (P<0.05). Additionally, the average daily gain, T-AOC, and cellulase content of calves in the SQBQP-H group significantly increased (P<0.05). Proteobacteria and Succinivibrio in the rumen flora of the SQBQP-H group was significantly lower than that of the C group (P<0.05). The relative abundance of Proteobacteria, Actinobacteria, Candidatus_Saccharibacteria, Deinococcus_Thermus, Cyanobacteria, and Succinivibrio in the SQBQP-H group was significantly increased (P<0.05), while the relative abundance of Tenericutes and Oscillibacter was significantly decreased (P<0.05). Serum metabolomics analysis revealed 20 differential metabolites, mainly enriched in amino acid biosynthesis, β-alanine metabolism, tyrosine, and tryptophan biosynthesis metabolic pathways (P<0.05). Correlation analysis results showed that Butyrivibrio in rumen flora and Oscillibacter_valericigenes in intestinal flora were significantly positively correlated with average daily gain, serum biochemical indexes, and differential metabolite (-)-Epigallocatechin (R>0.58, P<0.05).

Conclusion

SQBQP can promote calves weight gain and enhance health by modulating gastrointestinal flora and metabolic processes in the body.

Modulation of multiple sclerosis risk and pathogenesis by the gut microbiota: Complex interactions between host genetics, bacterial metabolism, and diet

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system, affecting nearly 2 million people worldwide. The etiology of MS is multifactorial: Approximately 30% of the MS risk is genetic, which implies that the remaining ~70% is environmental, with a number of factors proposed. One recently implicated risk factor for MS is the composition of the gut microbiome. Numerous case-control studies have identified changes in gut microbiota composition of people with MS (pwMS) compared with healthy control individuals, and more recent studies in animal models have begun to identify the causative microbes and underlying mechanisms. Here, we review some of these mechanisms, with a specific focus on the role of host genetic variation, dietary inputs, and gut microbial metabolism, with a particular emphasis on short-chain fatty acid and tryptophan metabolism. We put forward a model where, in an individual genetically susceptible to MS, the gut microbiota and diet can synergize as potent environmental modifiers of disease risk and possibly progression, with diet-dependent gut microbial metabolites serving as a key mechanism. We also propose that specific microbial taxa may have divergent effects in individuals carrying distinct variants of MS risk alleles or other polymorphisms, as a consequence of host gene-by-gut microbiota interactions. Finally, we also propose that the effects of specific microbial taxa, especially those that exert their effects through metabolites, are highly dependent on the host dietary intake. What emerges is a complex multifaceted interaction that has been challenging to disentangle in human studies, contributing to the divergence of findings across heterogeneous cohorts with differing geography, dietary preferences, and genetics. Nonetheless, this provides a complex and individualized, yet tractable, model of how the gut microbiota regulate susceptibility to MS, and potentially progression of this disease. Thus, we conclude that prophylactic or therapeutic modulation of the gut microbiome to prevent or treat MS will require a careful and personalized consideration of host genetics, baseline gut microbiota composition, and dietary inputs.

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

SCOPE

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

METHODS AND RESULTS

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

CONCLUSION

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

Isoflavones Effects on Vascular and Endothelial Outcomes: How Is the Gut Microbiota Involved?

Isoflavones are a group of (poly)phenols, also defined as phytoestrogens, with chemical structures comparable with estrogen, that exert weak estrogenic effects. These phytochemical compounds have been targeted for their proven antioxidant and protective effects. Recognizing the increasing prevalence of cardiovascular diseases (CVD), there is a growing interest in understanding the potential cardiovascular benefits associated with these phytochemical compounds. Gut microbiota may play a key role in mediating the effects of isoflavones on vascular and endothelial functions, as it is directly implicated in isoflavones metabolism. The findings from randomized clinical trials indicate that isoflavone supplementation may exert putative effects on vascular biomarkers among healthy individuals, but not among patients affected by cardiometabolic disorders. These results might be explained by the enzymatic transformation to which isoflavones are subjected by the gut microbiota, suggesting that a diverse composition of the microbiota may determine the diverse bioavailability of these compounds. Specifically, the conversion of isoflavones in equol-a microbiota-derived metabolite-seems to differ between individuals. Further studies are needed to clarify the intricate molecular mechanisms behind these contrasting results.

Antibiotic-altered gut microbiota explain host memory plasticity and disrupt pace-of-life covariation for an aquatic snail

There is mounting evidence that intestinal microbiota communities and their genes (the gut microbiome) influence how animals behave and interact with their environment, driving individual variation. Individual covariation in behavioural, physiological, and cognitive traits among individuals along a fast-slow continuum is thought to arise because these traits are linked as part of an adaptive pace-of-life strategy. Yet paradoxically, trait intercorrelation is absent or disrupted in some populations but not others. Here, we provide experimental evidence from aquatic pond snails (Lymnaea stagnalis) that environmental stressors and the gut microbiota explain host phenotypic plasticity and disrupted covariation among traits. Antibiotic exposure at varying levels of ecologically relevant concentrations had multiple effects starting with gut microbiota diversity, differential abundance, and inferred function. Memory declined in line with antibiotic concentrations that caused the most profound gut microbiota disruption, and although pace-of-life traits remained rigid, their covariation did not. Moreover, inferred microbial metabolic pathways with biologically relevant host functions explained individual and treatment variation in phenotypes. Together, our results point to the gut microbiome as a proximate mechanism influencing the emergence and maintenance of phenotypic variation within populations and highlights the need to decipher whether the gut microbiome's sensitivity to environmental pollution facilitates adaptive or maladaptive phenotypic plasticity.

Game of microbes: the battle within - gut microbiota and multiple sclerosis

Multiple sclerosis (MS) is a chronic and progressive autoimmune disease of the central nervous system (CNS), with both genetic and environmental factors contributing to the pathobiology of the disease. While human leukocyte antigen (HLA) genes have emerged as the strongest genetic factor, consensus on environmental risk factors are lacking. Recently, trillions of microbes residing in our gut (microbiome) have emerged as a potential environmental factor linked with the pathobiology of MS as PwMS show gut microbial dysbiosis (altered gut microbiome). Thus, there has been a strong emphasis on understanding the factors (host and environmental) regulating the composition of the gut microbiota and the mechanism(s) through which gut microbes contribute to MS disease, especially through immune system modulation. A better understanding of these interactions will help harness the enormous potential of the gut microbiota as a therapeutic approach to treating MS.

Naringenin confers protection against experimental autoimmune encephalomyelitis through modulating the gut-brain axis: A multiomics analysis

Multiple sclerosis (MS) is a disease of the central nervous system that involves the immune system attacking the protective covering of nerve fibers. This disease can be influenced by both environmental and genetic factors. Evidence has highlighted the critical role of the intestinal microbiota in MS and its animal model, experimental autoimmune encephalomyelitis (EAE). The composition of gut microflora is mainly determined by dietary components, which, in turn, modulate host homeostasis. A diet rich in naringenin at 0.5% can effectively mitigate the severity of EAE in mice. However, there is little direct data on the impact of naringenin at optimal doses on EAE development, as well as its intestinal microbiota and metabolites. Our study revealed that 2.0% naringenin resulted in the lowest clinical score and pathological changes in EAE mice, and altered the gene expression profiles associated with inflammation and immunity in spinal cord tissue. We then used untargeted metabolomics and 16S rRNA gene sequences to identify metabolites and intestinal microbiota, respectively. Naringenin supplementation enriched gut microbiota in EAE mice, including increasing the abundance of Paraprevotellaceae and Comamonadaceae, while decreasing the abundance of Deltaproteobacteria, RF39, and Desulfovibrionaceae. Furthermore, the changes in gut microbiota affected the production of metabolites in the feces and brain, suggesting a role in regulating the gut-brain axis. Finally, we conducted a fecal transplantation experiment to validate that gut microbiota partly mediates the effect of naringenin on EAE alleviation. In conclusion, naringenin has potential immunomodulatory effects that are influenced to some extent by the gut microbiome.

Increased serum α-tocopherol acetate mediated by gut microbiota ameliorates alveolar bone loss through the STAT3 signalling pathway in diabetic periodontitis

AIM

To evaluate whether and how gut microbiota-meditated metabolites regulate alveolar bone homeostasis in diabetic periodontitis (DP).

MATERIALS AND METHODS

Lactobacillus casei (L. casei) was employed as a positive modulator of gut microbiota in DP mice. The destruction of alveolar bone was evaluated. Untargeted metabolomics was conducted to screen out the pivotal metabolites. A co-housing experiment was conducted to determine the connection between the gut microbiota and alpha-tocopherol acetate (α-TA). α-TA was applied to DP mice to investigate its effect against alveolar bone loss. Human periodontal ligament cells (hPDLCs) and human gingival fibroblasts (HGFs) were extracted for the in vitro experiment. Transcriptomic analysis and immunohistochemistry were performed to detect the major affected signalling pathways.

RESULTS

Positive regulation of the gut microbiota significantly attenuated alveolar bone loss and increased the serum α-TA level. The alteration in gut microbiota composition could affect the serum α-T (the hydrolysates of α-TA) level. α-TA could alleviate alveolar bone destruction in DP mice and α-T exert beneficial effects on hPDLCs and HGFs. Mechanistically, the STAT3 signalling pathway was the pivotal pathway involved in the protective role of α-TA.

CONCLUSIONS

The gut microbiota-α-TA-STAT3 axis plays an important role in the regulation of diabetic alveolar bone homeostasis.

Diet-microbiome-immune interplay in multiple sclerosis: Understanding the impact of phytoestrogen metabolizing gut bacteria

Multiple sclerosis (MS) is a chronic and progressive autoimmune disease of the central nervous system (CNS), with both genetic and environmental factors contributing to the pathobiology of the disease. Although HLA genes have emerged as the strongest genetic factor linked to MS, consensus on the environmental risk factors is lacking. Recently, the gut microbiota has garnered increasing attention as a potential environmental factor in MS, as mounting evidence suggests that individuals with MS exhibit microbial dysbiosis (changes in the gut microbiome). Thus, there has been a strong emphasis on understanding the role of the gut microbiome in the pathobiology of MS, specifically, factors regulating the gut microbiota and the mechanism(s) through which gut microbes may contribute to MS. Among all factors, diet has emerged to have the strongest influence on the composition and function of gut microbiota. As MS patients lack gut bacteria capable of metabolizing dietary phytoestrogen, we will specifically discuss the role of a phytoestrogen diet and phytoestrogen metabolizing gut bacteria in the pathobiology of MS. A better understanding of these mechanisms will help to harness the enormous potential of the gut microbiota as potential therapeutics to treat MS and other autoimmune diseases.

Interactions between gut microbiota and polyphenols: A mechanistic and metabolomic review

BACKGROUND

Polyphenols are a class of naturally sourced compounds with widespread distribution and an extensive array of bioactivities. However, due to their complex constituents and weak absorption, a convincing explanation for their remarkable bioactivity remains elusive for a long time. In recent years, interaction with gut microbiota is hypothesized to be a reasonable explanation of the potential mechanisms for natural compounds especially polyphenols.

OBJECTIVES

This review aims to present a persuasive explanation for the contradiction between the limited bioavailability and the remarkable bioactivities of polyphenols by examining their interactions with gut microbiota.

METHODS

We assessed literatures published before April 10, 2023, from several databases, including Scopus, PubMed, Google Scholar, and Web of Science. The keywords used include "polyphenols", "gut microbiota", "short-chain fatty acids", "bile acids", "trimethylamine N-oxide", "lipopolysaccharides" "tryptophan", "dopamine", "intestinal barrier", "central nervous system", "lung", "anthocyanin", "proanthocyanidin", "baicalein", "caffeic acid", "curcumin", "epigallocatechin-3-gallate", "ferulic acid", "genistein", "kaempferol", "luteolin", "myricetin", "naringenin", "procyanidins", "protocatechuic acid", "pterostilbene", "quercetin", "resveratrol", etc. RESULTS: The review first demonstrates that polyphenols significantly alter gut microbiota diversity (α- and β-diversity) and the abundance of specific microorganisms. Polyphenols either promote or inhibit microorganisms, with various factors influencing their effects, such as dosage, treatment duration, and chemical structure of polyphenols. Furthermore, the review reveals that polyphenols regulate several gut microbiota metabolites, including short-chain fatty acids, dopamine, trimethylamine N-oxide, bile acids, and lipopolysaccharides. Polyphenols affect these metabolites by altering gut microbiota composition, modifying microbial enzyme activity, and other potential mechanisms. The changed microbial metabolites induced by polyphenols subsequently trigger host responses in various ways, such as acting as intestinal acid-base homeostasis regulators and activating on specific target receptors. Additionally, polyphenols are transformed into microbial derivatives by gut microbiota and these polyphenols' microbial derivatives have many potential advantages (e.g., increased bioactivity, improved absorption). Lastly, the review shows polyphenols maintain intestinal barrier, central nervous system, and lung function homeostasis by regulating gut microbiota.

CONCLUSION

The interaction between polyphenols and gut microbiota provides a credible explanation for the exceptional bioactivities of polyphenols. This review aids our understanding of the underlying mechanisms behind the bioactivity of polyphenols.

A UPLC-MS/MS Based Rapid, Sensitive, and Non-Enzymatic Methodology for Quantitation of Dietary Isoflavones in Biological Fluids

Dietary isoflavones, a type of phytoestrogens, have gained importance owing to their health-promoting benefits. However, the beneficial effects of isoflavones are mediated by smaller metabolites produced with the help of gut bacteria that are known to metabolize these phytoestrogenic compounds into Daidzein and Genistein and biologically active molecules such as S-Equol. Identifying and measuring these phytoestrogens and their metabolites is an important step towards understanding the significance of diet and gut microbiota in human health and diseases. We have overcome the reported difficulties in quantitation of these isoflavones and developed a simplified, sensitive, non-enzymatic, and sulfatases-free extraction methodology. We have subsequently used this method to quantify these metabolites in the urine of mice using UPLC-MS/MS. The extraction and quantitation method was validated for precision, linearity, accuracy, recoveries, limit of detection (LOD), and limit of quantification (LOQ). Linear calibration curves for Daidzein, Genistein, and S-Equol were set up by performing linear regression analysis and checked using the correlation coefficient (r2 > 0.995). LOQs for Daidzein, Genistein, and S-Equol were 2, 4, and 2 ng/mL, respectively. This UPLC-MS/MS swift method is suitable for quantifying isoflavones and the microbial-derived metabolite S-Equol in mice urine and is particularly useful for large numbers of samples.

Dendrobium officinale Polysaccharide Alleviates Type 2 Diabetes Mellitus by Restoring Gut Microbiota and Repairing Intestinal Barrier via the LPS/TLR4/TRIF/NF-kB Axis

Dendrobium officinale polysaccharide (DOP), the main active component, has a variety of bioactivities. In this study, a type 2 diabetes mellitus (T2DM) and antibiotic-induced pseudo-germ-free mouse models were used to investigate the hypoglycemic mechanisms of DOP. The findings showed that DOP ameliorated dysfunctional glucolipid metabolism, lipopolysaccharide (LPS) leakage, and metabolic inflammation levels in T2DM mice. Furthermore, DOP significantly upregulated the mRNA expression of tight junction proteins Claudin-1, Occludin, and ZO-1 and reduced intestinal inflammation and oxidative stress damage through the LPS/TLR4/TRIF/NF-κB axis to repair the intestinal barrier. Interestingly, pseudo-germ-free mouse experiments confirmed that the above beneficial effects of DOP were dependent on gut microbiota. 16S rRNA analysis showed that DOP strongly inhibited the harmful bacterium Helicobacter by 94.57% and facilitated the proliferation of probiotics Allobaculum, Bifidobacterium, and Lactobacillus by 34.96, 139.41, and 88.95%, respectively. Therefore, DOP is capable of rebuilding certain specific intestinal microbiota to restore intestinal barrier injury, which supports the utilization of DOP as a new type of prebiotic in functional foods for T2DM.

Looking at the Full Picture: Utilizing Topic Modeling to Determine Disease-Associated Microbiome Communities

The microbiome is a complex micro-ecosystem that provides the host with pathogen defense, food metabolism, and other vital processes. Alterations of the microbiome (dysbiosis) have been linked with a number of diseases such as cancers, multiple sclerosis (MS), Alzheimer's disease, etc. Generally, differential abundance testing between the healthy and patient groups is performed to identify important bacteria (enriched or depleted in one group). However, simply providing a singular species of bacteria to an individual lacking that species for health improvement has not been as successful as fecal matter transplant (FMT) therapy. Interestingly, FMT therapy transfers the entire gut microbiome of a healthy (or mixture of) individual to an individual with a disease. FMTs do, however, have limited success, possibly due to concerns that not all bacteria in the community may be responsible for the healthy phenotype. Therefore, it is important to identify the community of microorganisms linked to the health as well as the disease state of the host. Here we applied topic modeling, a natural language processing tool, to assess latent interactions occurring among microbes; thus, providing a representation of the community of bacteria relevant to healthy vs. disease state. Specifically, we utilized our previously published data that studied the gut microbiome of patients with relapsing-remitting MS (RRMS), a neurodegenerative autoimmune disease that has been linked to a variety of factors, including a dysbiotic gut microbiome. With topic modeling we identified communities of bacteria associated with RRMS, including genera previously discovered, but also other taxa that would have been overlooked simply with differential abundance testing. Our work shows that topic modeling can be a useful tool for analyzing the microbiome in dysbiosis and that it could be considered along with the commonly utilized differential abundance tests to better understand the role of the gut microbiome in health and disease.

Application of plant specialized metabolites to modulate soil microbiota

Plant specialized metabolites (PSMs) are considerably diverse compounds with multifaceted roles in the adaptation of plants to various abiotic and biotic stresses. PSMs are frequently secreted into the rhizosphere, a small region around the roots, where they facilitate interactions between plants and soil microorganisms. PSMs shape the host-specific rhizosphere microbial communities that potentially influence plant growth and tolerance to adverse conditions. Plant mutants defective in PSM biosynthesis contribute to reveal the roles of each PSM in plant-microbiota interactions in the rhizosphere. Recently, various approaches have been used to directly supply PSMs to soil by in vitro methods or through addition in pots with plants. This review focuses on the feasibility of the direct PSM application methods to reveal rhizospheric plant-microbiota interactions and discusses the possibility of applying the knowledge gained to future engineering of rhizospheric traits.

Dietary supplementation of Allium mongolicum modulates rumen-hindgut microbial community structure in Simmental calves

Compared to traditional herbage, functional native herbage is playing more important role in ruminant agriculture through improving digestion, metabolism and health of livestock; however, their effects on rumen microbial communities and hindgut fermentation are still not well understood. The objective of present study was to evaluate the effects of dietary addition of Allium mongolicum on bacterial communities in rumen and feces of claves. Sixteen 7-month-old male calves were randomly divided into four groups (n = 4). All calves were fed a basal ration containing roughage (alfalfa and oats) and mixed concentrate in a ratio of 60:40 on dry matter basis. In each group, the basal ration was supplemented with Allium mongolicum 0 (SL0), 200 (SL200), 400 (SL400), and 800 (SL800) mg/kg BW. The experiment lasted for 58 days. Rumen fluid and feces in rectum were collected, Rumen fluid and hindgut fecal were collected for analyzing bacterial community. In the rumen, Compared with SL0, there was a greater relative abundance of phylum Proteobacteria (p < 0.05) and genera Rikenellaceae_RC9_gut_group (p < 0.01) in SL800 treatment. In hindgut, compared with SL0, supplementation of A. mongolicum (SL200, SL400, or SL800) decreased in the relative abundances of Ruminococcaceae_UCG-014 (p < 0.01), Ruminiclostridium_5 (p < 0.01), Eubacterium_coprostanoligenes_group (p < 0.05), and Alistipes (p < 0.05) in feces; Whereas, the relative abundances of Christensenellaceae_R-7_group (p < 0.05), and Prevotella_1 (p < 0.01) in SL800 were higher in feces, to maintain hindgut stability. This study provided evidence that A. mongolicum affects the gastrointestinal of calves, by influencing microbiota in their rumen and feces.

Alteration of faecal microbiota balance related to long-term deep meditation

Background

Advancements in research have confirmed that gut microbiota can influence health through the microbiota-gut-brain axis. Meditation, as an inner mental exercise, can positively impact the regulation of an individual's physical and mental health. However, few studies have comprehensively investigated faecal microbiota following long-term (several years) deep meditation. Therefore, we propose that long-term meditation may regulate gut microbiota homeostasis and, in turn, affect physical and mental health.

Aims

To investigate the effects of long-term deep meditation on the gut microbiome structure.

Methods

To examine the intestinal flora, 16S rRNA gene sequencing was performed on faecal samples of 56 Tibetan Buddhist monks and neighbouring residents. Based on the sequencing data, linear discriminant analysis effect size (LEfSe) was employed to identify differential intestinal microbial communities between the two groups. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) analysis was used to predict the function of faecal microbiota. In addition, we evaluated biochemical indices in the plasma.

Results

The α-diversity indices of the meditation and control groups differed significantly. At the genus level, Prevotella and Bacteroides were significantly enriched in the meditation group. According to the LEfSe analysis, two beneficial bacterial genera (Megamonas and Faecalibacterium) were significantly enriched in the meditation group. Functional predictive analysis further showed that several pathways-including glycan biosynthesis, metabolism and lipopolysaccharide biosynthesis-were significantly enriched in the meditation group. Moreover, plasma levels of clinical risk factors were significantly decreased in the meditation group, including total cholesterol and apolipoprotein B.

Conclusions

Long-term traditional Tibetan Buddhist meditation may positively impact physical and mental health. We confirmed that the gut microbiota composition differed between the monks and control subjects. The microbiota enriched in monks was associated with a reduced risk of anxiety, depression and cardiovascular disease and could enhance immune function. Overall, these results suggest that meditation plays a positive role in psychosomatic conditions and well-being.

Isoflavone consumption reduces inflammation through modulation of phenylalanine and lipid metabolism

INTRODUCTION

Phytoestrogens found in soy, fruits, peanuts, and other legumes, have been identified as metabolites capable of providing beneficial effects in multiple pathological conditions due to their ability to mimic endogenous estrogen. Interestingly, the health-promoting effects of some phytoestrogens, such as isoflavones, are dependent on the presence of specific gut bacteria. Specifically, gut bacteria can metabolize isoflavones into equol, which has a higher affinity for endogenous estrogen receptors compared to dietary isoflavones. We have previously shown that patients with multiple sclerosis (MS), a neuroinflammatory disease, lack gut bacteria that are able to metabolize phytoestrogen. Further, we have validated the importance of both isoflavones and phytoestrogen-metabolizing gut bacteria in disease protection utilizing an animal model of MS. Specifically, we have shown that an isoflavone-rich diet can protect from neuroinflammatory diseases, and that protection was dependent on the ability of gut bacteria to metabolize isoflavones into equol. Additionally, mice on a diet with isoflavones showed an anti-inflammatory response compared to the mice on a diet lacking isoflavones. However, it is unknown how isoflavones and/or equol mediates their protective effects, especially their effects on host metabolite levels.

OBJECTIVES

In this study, we utilized untargeted metabolomics to identify metabolites found in plasma that were modulated by the presence of dietary isoflavones.

RESULTS

We found that the consumption of isoflavones increased anti-inflammatory monounsaturated fatty acids and beneficial polyunsaturated fatty acids while reducing pro-inflammatory glycerophospholipids, sphingolipids, phenylalanine metabolism, and arachidonic acid derivatives.

CONCLUSION

Isoflavone consumption alters the systemic metabolic landscape through concurrent increases in monounsaturated fatty acids and beneficial polyunsaturated fatty acids plus reduction in pro-inflammatory metabolites and pathways. This highlights a potential mechanism by which an isoflavone diet may modulate immune-mediated disease.