Effects of Metabolites Derived From Gut Microbiota and Hosts on Pathogens

Rhodobacter sphaeroides supplementation improves defense ability of Chinese mitten crab Eriocheir sinensis against Shewanella putrefaciens infection via intestinal flora and metabolism regulation

Shewanella putrefaciens is a vital bacterial pathogen implicated in serious diseases in Chinese mitten crab Eriocheir sinensis. Yet the use of probiotics to improve the defense ability of E. sinensis against S. putrefaciens infection remains poorly understood. In the present study, the protective effect of dietary R. sphaeroides against S. putrefaciens infection in E. sinensis was evaluated through antioxidant capability, immune response, and survival under bacterial challenge assays, and its protective mechanism was further explored using a combination of intestinal flora and metabolome assays. Our results indicated that dietary R. sphaeroides could significantly improve immunity and antioxidant ability of Chinese mitten crabs, thereby strengthening their disease resistance with the relative percentage survival of 81.09% against S. putrefaciens. In addition, dietary R. sphaeroides could significantly alter the intestinal microbial composition and intestinal metabolism of crabs, causing not only the reduction of potential threatening pathogen load but also the increase of differential metabolites in tryptophan metabolism, pyrimidine metabolism, and glycerophospholipid metabolism. Furthermore, the regulation of differential metabolites such as N-Acetylserotonin positively correlated with beneficial Rhodobacter could be a potential protection strategy for Shewanella infection. To the best of our knowledge, this is the first study to illustrate the protective effect and mechanism of R. sphaeroides supplementation to protect E. sinensis against S. putrefaciens infection.

Metabolic immaturity of newborns and breast milk bile acid metabolites are the central determinants of heightened neonatal vulnerability to norovirus diarrhea

Noroviruses are the leading global cause of acute gastroenteritis, responsible for 685 million annual cases. While all age groups are susceptible to noroviruses, children are vulnerable to more severe infections than adults, underscored by 200 million pediatric cases and up to 200,000 deaths in children annually. Understanding the basis for the increased vulnerability of young hosts is critical to developing effective treatments. The pathogenic outcome of any enteric virus infection is governed by a complex interplay between the virus, intestinal microbiota, and host immune factors. A central mediator in these complex relationships are host- and microbiota-derived metabolites. Noroviruses bind a specific class of metabolites, bile acids, which are produced by the host and then modified by commensal bacterial enzymes. Paradoxically, bile acids can have both proviral and antiviral roles during norovirus infections. Considering these opposing effects, the microbiota-regulated balance of the bile acid pool may be a key determinant of the pathogenic outcome of a norovirus infection. The bile acid pool in newborns is unique due to immaturity of host metabolic pathways and developing gut microbiota, which could underlie the vulnerability of these hosts to severe norovirus infections. Supporting this concept, we demonstrate herein that microbiota and their bile acid metabolites protect from severe norovirus diarrhea whereas host-derived bile acids promote disease. Remarkably, we also report that maternal bile acid metabolism determines neonatal susceptibility to norovirus diarrhea during breastfeeding by delivering proviral bile acids to the newborn. Finally, directed targeting of maternal and neonatal bile acid metabolism can protect the neonatal host from norovirus disease. Altogether, these data support the conclusion that metabolic immaturity in newborns and ingestion of proviral maternal metabolites in breast milk are the central determinants of heightened neonatal vulnerability to norovirus disease.

The Effect of Clostridium butyricum on Gut Microbial Changes and Functional Profiles of Metabolism in High-fat Diet-fed Rats Depending on Age and Sex

Background/Aims

A high-fat diet (HFD) causes dysbiosis and promotes inflammatory responses in the colon. This study aims to evaluate the effects of Clostridium butyricum on HFD-induced gut microbial changes in rats.

Methods

Six-week-old Fischer-344 rats with both sexes were given a control or HFD during 8 weeks, and 1-to-100-fold diluted Clostridium butyricum were administered by gavage. Fecal microbiota analyses were conducted using 16S ribosomal RNA metagenomic sequencing and predictive functional profiling of microbial communities in metabolism.

Results

A significant increase in Ruminococcaceae and Lachnospiraceae, which are butyric acid-producing bacterial families, was observed in the probiotics groups depending on sex. In contrast, Akkermansia muciniphila, which increased through a HFD regardless of sex, and decreased in the probiotics groups. A. muciniphila positively correlated with Claudin-1 expression in males (P < 0.001) and negatively correlated with the expression of Claudin-2 (P = 0.042), IL-1β (P = 0.037), and IL-6 (P = 0.044) in females. In terms of functional analyses, a HFD decreased the relative abundances of M00131 (carbohydrate metabolism module), M00579, and M00608 (energy metabolism), and increased those of M00307 (carbohydrate metabolism), regardless of sex. However, these changes recovered especially in male C. butyricum groups. Furthermore, M00131, M00579, and M00608 showed a positive correlation and M00307 showed a negative correlation with the relative abundance of A. muciniphila (P < 0.001).

Conclusion

The beneficial effects of C. butyricum on HFD-induced gut dysbiosis in young male rats originate from the functional profiles of carbohydrate and energy metabolism.

Cell-Free Supernatant of Lactobacillus rhamnosus and Bifidobacterium breve Ameliorates Ischemic Stroke-Generated Neurological Deficits in Rats

The beneficial effects of probiotics, postbiotics, and paraprobiotics have already been registered in managing ischemic stroke-generated neuroinflammation and gut dysbiosis. Herein, we examined the impact of cell-free supernatant (CFS) obtained from probiotics (Lactobacillus rhamnosus UBLR-58 and Bifidobacterium breve UBBr-01) in a rat transient middle cerebral artery occlusion (MCAO) model of focal cerebral injury. Pre-MCAO supplementation of probiotics (2 × 109 CFU/mL) for 21 days or CFS (1 mL/rat) for 7 days protect the MCAO-induced somatosensory and motor impairments recorded at 24 h and 72 h after reperfusion in foot-fault, rotarod, adhesive removal, and vibrissae-evoked forelimb placing tests. We also noted the reduced infarct area and neuronal degradation in the right hemisphere of probiotics- and CFS-recipient MCAO-operated animals. Moreover, MCAO-induced altered concentrations of glial-fibrillary acidic protein, NeuN, zonula occludens-1 (ZO-1), TLR4, IL-1β, IL-6, and TNF-α, as well as matrix metalloproteinase-9 (MMP9) were reversed in the treatment groups. Probiotics and CFS treatment ameliorated the elevated levels of IL-6, IL-1β, and MMP9 in the blood plasma of rats. The disrupted microbial phyla, Firmicutes-to-Bacteroides ratio, villi/crypt ratio, and decreased mucin-producing goblet cells, ZO-1, and occludin in the colon of MCAO-operated rats were recovered following probiotics and CFS treatment. NMR characterization of CFS and rat blood plasma revealed the presence of several important bacterial metabolites. These findings suggest that the CFS obtained from Lactobacillus rhamnosus UBLR-58 and Bifidobacterium breve UBBr-01 has the propensity to improve MCAO-generated neurological dysfunctions in rats by dampening neuroinflammation and modulating the gut-brain axis modulators.

Theabrownin from Fu Brick tea ameliorates high-fat induced insulin resistance, hepatic steatosis, and inflammation in mice by altering the composition and metabolites of gut microbiota

Fu Brick tea belongs to fermented dark tea, which is one of the six categories of tea. Fu Brick tea has been reported to reduce adiposity and has beneficial effects in the treatment of hypercholesterolemia and cardiovascular disease. Theabrownin (TB) is one of the pigments with the most abundant content in Fu Brick tea. TB has also been reported to have lipid-lowering effects, but its mechanism remains unclear. We found that TB could effectively reduce the insulin resistance and fat deposition induced by a high fat diet (HFD), decrease inflammation in the liver, improve intestinal integrity, and reduce endotoxins in circulation. Further studies showed that TB increased the abundance of Verrucomicrobiota and reduced the abundance of Firmicutes and Desulfobacterota in the intestinal tract of obese mice. The alteration of gut microbiota is closely linked to the metabolic phenotype after TB treatment through correlation analysis. Moreover, TB changed the gut microbial metabolites including L-ornithine, α-ketoglutarate, and glutamine, which have also been found to be upregulated in the liver after TB intervention. In vitro, L-ornithine, α-ketoglutarate, or glutamine significantly reduced lipopolysaccharide (LPS)-induced inflammation in macrophages. Therefore, our results suggest that TB can reduce adiposity, systemic insulin resistance, and liver inflammation induced by a HFD through altering gut microbiota and improving the intestinal tight junction integrity. The metabolites of gut microbiota might also play a role in ameliorating the HFD-induced phenotype by TB.

Blood lipids mediate the effects of gut microbiome on endometriosis: a mendelian randomization study

BACKGROUND

There is evidence for an association between the gut microbiome and endometriosis. However, their causal relationship and the mediating role of lipid metabolism remain unclear.

METHODS

Using genome-wide association study (GWAS) data, we conducted a bidirectional Mendelian randomization (MR) analysis to investigate the causal relationships between gut microbiome and endometriosis. The inverse variance weighted (IVW) method was used as the primary model, with other MR models used for comparison. Sensitivity analysis based on different statistical assumptions was used to evaluate whether the results were robust. A two-step MR analysis was further conducted to explore the mediating effects of lipids, by integrating univariable MR and the multivariate MR method based on the Bayesian model averaging method (MR-BMA).

RESULTS

We identified four possible intestinal bacteria genera associated with the risk of endometriosis through the IVW method, including Eubacterium ruminantium group (odds ratio [OR] = 0.881, 95% CI: 0.795-0.976, P = 0.015), Anaerotruncus (OR = 1.252, 95% CI: 1.028-1.525, P = 0.025), Olsenella (OR = 1.110, 95% CI: 1.007-1.223, P = 0.036), and Oscillospira (OR = 1.215, 95% CI: 1.014-1.456, P = 0.035). The further two-step MR analysis identified that the effect of Olsenella on endometriosis was mediated by triglycerides (proportion mediated: 3.3%; 95% CI = 1.5-5.1%).

CONCLUSION

This MR study found evidence for specific gut microbiomes associated with the risk of endometriosis, which might partially be mediated by triglycerides.

Role of the gut microbiota in hematologic cancer

Hematologic neoplasms represent 6.5% of all cancers worldwide. They are characterized by the uncontrolled growth of hematopoietic and lymphoid cells and a decreased immune system efficacy. Pathological conditions in hematologic cancer could disrupt the balance of the gut microbiota, potentially promoting the proliferation of opportunistic pathogens. In this review, we highlight studies that analyzed and described the role of gut microbiota in different types of hematologic diseases. For instance, myeloma is often associated with Pseudomonas aeruginosa and Clostridium leptum, while in leukemias, Streptococcus is the most common genus, and Lachnospiraceae and Ruminococcaceae are less prevalent. Lymphoma exhibits a moderate reduction in microbiota diversity. Moreover, certain factors such as delivery mode, diet, and other environmental factors can alter the diversity of the microbiota, leading to dysbiosis. This dysbiosis may inhibit the immune response and increase susceptibility to cancer. A comprehensive analysis of microbiota-cancer interactions may be useful for disease management and provide valuable information on host-microbiota dynamics, as well as the possible use of microbiota as a distinguishable marker for cancer progression.

Effect of short-term consumption of yellow peas as noodles on the intestinal environment: A single-armed pre-post comparative pilot study

Legumes contain dietary fiber and resistant starch, which are beneficial to the intestinal environment. Here, we investigated the effects of yellow pea noodle consumption on the gut microbiota and fecal metabolome of healthy individuals. This single-armed pre-post comparative pilot study evaluated eight healthy female participants who consumed yellow pea noodles for 4 weeks. The gut microbiota composition and fecal metabolomic profile of each participant were evaluated before (2 weeks), during (4 weeks), and after (4 weeks) daily yellow pea noodle consumption. 16S rRNA gene sequencing was performed on stool samples, followed by clustering of operational taxonomic units using the Cluster Database at High Identity with Tolerance and integrated QIIME pipeline to elucidate the gut microbiota composition. The fecal metabolites were analyzed using capillary electrophoresis time-of-flight mass spectrometry and liquid chromatography time-of-flight mass spectrometry. Compared to day 0, the relative abundances of five bacterial genera (Bacteroides, Bilophila, Hungatella, Parabacteroides, and Streptococcus) in the intestinal microbiota significantly decreased, wherein those of Bifidobacterium longum and Ruminococcus bromii were increased on day 29 and decreased to the basal level (day 0) on day 57. Fecal metabolomic analysis identified 11 compounds showing significant fluctuations in participants on day 29 compared to day 0. Although the average levels of short-chain fatty acids in participants did not differ significantly on day 29 compared to those on day 0, the levels tended to increase in individual participants with >8% relative abundance of R. bromii in their gut microbiota. In conclusion, incorporating yellow peas as a daily staple may confer human health benefits by favorably altering the intestinal environment.

Mini-review: microbiota have potential to prevent PEDV infection by improved intestinal barrier

Porcine epidemic diarrhea virus (PEDV) infection poses a significant threat to the global pig industry. Current prevention and control strategies are inadequate in protecting pigs from new PEDV variants. This review aims to examine the relationship between PEDV and intestinal microbes, and investigate whether modulating intestinal microbes could affect PEDV infection. The mechanisms by which various intestinal microbes affect viral infection were initially introduced. Intestinal microbes can influence enteric viral infection through direct contact, such as binding, or by affecting interferons (IFNs) production and the intestinal barrier. Influencing the intestinal barrier by microbes can impact PEDV infection in young piglets. To narrow down the range of microbes that may influence PEDV infection, this review summarized microbes that change after infection. Short chain fatty acids (SCFAs), bacterial cell components, and toxins from microbes were identified as important mediators affecting PEDV infection. SCFAs primarily strengthen the intestinal barrier and inhibit intestinal inflammation, while bacterial cell components and toxins are more likely to damage the intestinal barrier. Therefore, this review hypothesizes that fecal transplantation, which allows the host to colonize more SCFAs-producing microbes, may prevent PEDV infection. However, these hypotheses require further proof, and the transplantation of intestinal microbes in pigs requires more exploration.

How Do Microorganisms Influence the Development of Endometriosis? Participation of Genital, Intestinal and Oral Microbiota in Metabolic Regulation and Immunopathogenesis of Endometriosis

Microorganisms inhabiting the human body play an extremely key role in its proper functioning, as well as in the development of the immune system, which, by maintaining the immune balance, allows you to enjoy health. Dysbiosis of the intestinal microbiota, or in the oral cavity or reproductive tract, understood as a change in the number and diversity of all microorganisms inhabiting them, may correlate with the development of many diseases, including endometriosis, as researchers have emphasized. Endometriosis is an inflammatory, estrogen-dependent gynecological condition defined by the growth of endometrial cells outside the uterine cavity. Deregulation of immune homeostasis resulting from microbiological disorders may generate chronic inflammation, thus creating an environment conducive to the increased adhesion and angiogenesis involved in the development of endometriosis. In addition, research in recent years has implicated bacterial contamination and immune activation, reduced gastrointestinal function by cytokines, altered estrogen metabolism and signaling, and abnormal progenitor and stem cell homeostasis, in the pathogenesis of endometriosis. The aim of this review was to present the influence of intestinal, oral and genital microbiota dysbiosis in the metabolic regulation and immunopathogenesis of endometriosis.

Disruption of fish gut microbiota composition and holobiont's metabolome during a simulated Microcystis aeruginosa (Cyanobacteria) bloom

BACKGROUND

Cyanobacterial blooms are one of the most common stressors encountered by metazoans living in freshwater lentic systems such as lakes and ponds. Blooms reportedly impair fish health, notably through oxygen depletion and production of bioactive compounds including cyanotoxins. However, in the times of the "microbiome revolution", it is surprising that so little is still known regarding the influence of blooms on fish microbiota. In this study, an experimental approach is used to demonstrate that blooms affect fish microbiome composition and functions, as well as the metabolome of holobionts. To this end, the model teleost Oryzias latipes is exposed to simulated Microcystis aeruginosa blooms of various intensities in a microcosm setting, and the response of bacterial gut communities is evaluated in terms of composition and metabolome profiling. Metagenome-encoded functions are compared after 28 days between control individuals and those exposed to highest bloom level.

RESULTS

The gut bacterial community of O. latipes exhibits marked responses to the presence of M. aeruginosa blooms in a dose-dependent manner. Notably, abundant gut-associated Firmicutes almost disappear, while potential opportunists increase. The holobiont's gut metabolome displays major changes, while functions encoded in the metagenome of bacterial partners are more marginally affected. Bacterial communities tend to return to original composition after the end of the bloom and remain sensitive in case of a second bloom, reflecting a highly reactive gut community.

CONCLUSION

Gut-associated bacterial communities and holobiont functioning are affected by both short and long exposure to M. aeruginosa, and show evidence of post-bloom resilience. These findings point to the significance of bloom events to fish health and fitness, including survival and reproduction, through microbiome-related effects. In the context of increasingly frequent and intense blooms worldwide, potential outcomes relevant to conservation biology as well as aquaculture warrant further investigation. Video Abstract.

Revitalizing myocarditis treatment through gut microbiota modulation: unveiling a promising therapeutic avenue

Numerous studies have demonstrated that gut microbiota plays an important role in the development and treatment of different cardiovascular diseases, including hypertension, heart failure, myocardial infarction, arrhythmia, and atherosclerosis. Furthermore, evidence from recent studies has shown that gut microbiota contributes to the development of myocarditis. Myocarditis is an inflammatory disease that often results in myocardial damage. Myocarditis is a common cause of sudden cardiac death in young adults. The incidence of myocarditis and its associated dilated cardiomyopathy has been increasing yearly. Myocarditis has gained significant attention on social media due to its association with both COVID-19 and COVID-19 vaccinations. However, the current therapeutic options for myocarditis are limited. In addition, little is known about the potential therapeutic targets of myocarditis. In this study, we review (1) the evidence on the gut-heart axis, (2) the crosslink between gut microbiota and the immune system, (3) the association between myocarditis and the immune system, (4) the impact of gut microbiota and its metabolites on myocarditis, (5) current strategies for modulating gut microbiota, (6) challenges and future directions for targeted gut microbiota in the treatment of myocarditis. The approach of targeting the gut microbiota in myocarditis is still in its infancy, and this is the study to explore the gut microbiota-immune system-myocarditis axis. Our findings are expected to pave the way for the use of gut microbiota as a potential therapeutic target in the treatment of myocarditis.

Metabolite interactions between host and microbiota during health and disease: Which feeds the other?

Metabolites produced by the host and microbiota play a crucial role in how human bodies develop and remain healthy. Most of these metabolites are produced by microbiota and hosts in the digestive tract. Metabolites in the gut have important roles in energy metabolism, cellular communication, and host immunity, among other physiological activities. Although numerous host metabolites, such as free fatty acids, amino acids, and vitamins, are found in the intestine, metabolites generated by gut microbiota are equally vital for intestinal homeostasis. Furthermore, microbiota in the gut is the sole source of some metabolites, including short-chain fatty acids (SCFAs). Metabolites produced by microbiota, such as neurotransmitters and hormones, may modulate and significantly affect host metabolism. The gut microbiota is becoming recognized as a second endocrine system. A variety of chronic inflammatory disorders have been linked to aberrant host-microbiota interplays, but the precise mechanisms underpinning these disturbances and how they might lead to diseases remain to be fully elucidated. Microbiome-modulated metabolites are promising targets for new drug discovery due to their endocrine function in various complex disorders. In humans, metabolotherapy for the prevention or treatment of various disorders will be possible if we better understand the metabolic preferences of bacteria and the host in specific tissues and organs. Better disease treatments may be possible with the help of novel complementary therapies that target host or bacterial metabolism. The metabolites, their physiological consequences, and functional mechanisms of the host-microbiota interplays will be highlighted, summarized, and discussed in this overview.

Effects of OsomeFood Clean Label plant-based meals on the gut microbiome

BACKGROUND

Plant-based diets offer more beneficial microbes and can modulate gut microbiomes to improve human health. We evaluated the effects of the plant-based OsomeFood Clean Label meal range ('AWE' diet), on the human gut microbiome.

METHODS

Over 21 days, ten healthy participants consumed OsomeFood meals for five consecutive weekday lunches and dinners and resumed their regular diets for other days/meals. On follow-up days, participants completed questionnaires to record satiety, energy and health, and provided stool samples. To document microbiome variations and identify associations, species and functional pathway annotations were analyzed by shotgun sequencing. Shannon diversity and regular diet calorie intake subsets were also assessed.

RESULTS

Overweight participants gained more species and functional pathway diversity than normal BMI participants. Nineteen disease-associated species were suppressed in moderate-responders without gaining diversity, and in strong-responders with diversity gains along with health-associated species. All participants reported improved short-chain fatty acids production, insulin and γ-aminobutyric acid signaling. Moreover, fullness correlated positively with Bacteroides eggerthii; energetic status with B. uniformis, B. longum, Phascolarctobacterium succinatutens, and Eubacterium eligens; healthy status with Faecalibacterium prausnitzii, Prevotella CAG 5226, Roseburia hominis, and Roseburia sp. CAG 182; and overall response with E. eligens and Corprococcus eutactus. Fiber consumption was negatively associated with pathogenic species.

CONCLUSION

Although the AWE diet was consumed for only five days a week, all participants, especially overweight ones, experienced improved fullness, health status, energy and overall responses. The AWE diet benefits all individuals, especially those of higher BMI or low-fiber consumption.

Exercise-acclimated microbiota improves skeletal muscle metabolism via circulating bile acid deconjugation

Habitual exercise alters the intestinal microbiota composition, which may mediate its systemic benefits. We examined whether transplanting fecal microbiota from trained mice improved skeletal muscle metabolism in high-fat diet (HFD)-fed mice. Fecal samples from sedentary and exercise-trained mice were gavage-fed to germ-free mice. After receiving fecal samples from trained donor mice for 1 week, recipient mice had elevated levels of AMP-activated protein kinase (AMPK) and insulin growth factor-1 in skeletal muscle. In plasma, bile acid (BA) deconjugation was found to be promoted in recipients transplanted with feces from trained donor mice; free-form BAs also induced more AMPK signaling and glucose uptake than tauro-conjugated BAs. The transplantation of exercise-acclimated fecal microbiota improved glucose tolerance after 8 weeks of HFD administration. Intestinal microbiota may mediate exercise-induced metabolic improvements in mice by modifying circulating BAs. Our findings provide insights into the prevention and treatment of metabolic diseases.

Retroviral Infection and Commensal Bacteria Dependently Alter the Metabolomic Profile in a Sterile Organ

Both viruses and bacteria produce "pathogen associated molecular patterns" that may affect microbial pathogenesis and anti-microbial responses. Additionally, bacteria produce metabolites, while viruses could change the metabolic profiles of the infected cells. Here, we used an unbiased metabolomics approach to profile metabolites in spleens and blood of murine leukemia virus-infected mice monocolonized with Lactobacillus murinus to show that viral infection significantly changes the metabolite profile of monocolonized mice. We hypothesize that these changes could contribute to viral pathogenesis or to the host response against the virus and thus open a new avenue for future investigations.

Retroviral infection and commensal bacteria dependently alter the metabolomic profile in a sterile organ

Both viruses and bacteria produce 'pathogen associated molecular patterns' that may affect microbial pathogenesis and anti-microbial responses. Additionally, bacteria produce metabolites while viruses could change metabolic profiles of the infected cells. Here, we used an unbiased metabolomics approach to profile metabolites in spleens and blood of Murine Leukemia Virus-infected mice monocolonized with Lactobacillus murinus to show that viral infection significantly changes the metabolite profile of monocolonized mice. We hypothesize that these changes could contribute to viral pathogenesis or to the host response against the virus and thus, open a new avenue for future investigations.

ALZHEIMER'S DISEASE AND ITS RELATIONSHIP WITH THE MICROBIOTA-GUT-BRAIN AXIS

BACKGROUND

Alzheimer's disease (AD) is a progressive and irreversible neurodegenerative disease, characterized by the accumulation of amyloid plaques and neurofibrillary tangles in the brain. Several pathways enable bidirectional communication between the central nervous system (CNS), the intestine and its microbiota, constituting the microbiota-gut-brain axis.

OBJECTIVE

Review the pathophysiology of AD, relate it to the microbiota-gut-brain axis and discuss the possibility of using probiotics in the treatment and/or prevention of this disease.

METHODS

Search of articles from the PubMed database published in the last 5 years (2017 to 2022) structure the narrative review.

RESULTS

The composition of the gut microbiota influences the CNS, resulting in changes in host behavior and may be related to the development of neurodegenerative diseases. Some metabolites produced by the intestinal microbiota, such as trimethylamine N-oxide (TMAO), may be involved in the pathogenesis of AD, while other compounds produced by the microbiota during the fermentation of food in the intestine, such as D-glutamate and fatty acids short chain, are beneficial in cognitive function. The consumption of live microorganisms beneficial to health, known as probiotics, has been tested in laboratory animals and humans to evaluate the effect on AD.

CONCLUSION

Although there are few clinical trials evaluating the effect of probiotic consumption in humans with AD, the results to date indicate a beneficial contribution of the use of probiotics in this disease.

Dietary grape pomace extract supplementation improved meat quality, antioxidant capacity, and immune performance in finishing pigs

In pig production, reducing production costs and improving immunity are important. Grape pomace, a good agricultural by-product, has been thrown away as food waste for a long time. Recently, we found that it could be used as a new source of pig feed. We investigated the effect of grape pomace on inflammation, gut barrier function, meat quality, and growth performance in finishing pigs. Our results indicated that treatment samples showed a significant decrease in water loss, IL-1β, DAO, ROS, and MDA content (p < 0.05). IgA, IgG, IgM, CAT, T-AOC, SOD, and IFN-γ significantly increased compared with those in control samples (p < 0.05). Meanwhile, the relative mRNA expression of the tight junction protein occludin showed a significant difference (p < 0.05). Analysis of metagenomic sequencing indicated that grape pomace significantly decreased the relative abundance of Treponema and Streptococcus (p < 0.05). In summary, our results demonstrated that grape pomace could improve meat quality, alleviate inflammation, and decrease oxidative stress.

Homeostasis and Dysbiosis of the Intestinal Microbiota: Comparing Hallmarks of a Healthy State with Changes in Inflammatory Bowel Disease

The gut microbiota, which represent a community of different microorganisms in the human intestinal tract, are crucial to preserving human health by participating in various physiological functions and acting as a metabolic organ. In physiological conditions, microbiota-host partnership exerts homeostatic stability; however, changes in intestinal microbiota composition (dysbiosis) are an important factor in the pathogenesis of inflammatory bowel disease and its two main disease entities: ulcerative colitis and Crohn's disease. The incidence and prevalence of these inflammatory conditions have increased rapidly in the last decade, becoming a significant problem for the healthcare system and a true challenge in finding novel therapeutic solutions. The issue is that, despite numerous studies, the etiopathogenesis of inflammatory bowel disease is not completely clear. Based on current knowledge, chronic intestinal inflammation occurs due to altered intestinal microbiota and environmental factors, as well as a complex interplay between the genetic predisposition of the host and an inappropriate innate and acquired immune response. It is important to note that the development of biological and immunomodulatory therapy has led to significant progress in treating inflammatory bowel disease. Certain lifestyle changes and novel approaches-including fecal microbiota transplantation and nutritional supplementation with probiotics, prebiotics, and synbiotics-have offered solutions for dysbiosis management and paved the way towards restoring a healthy microbiome, with only minimal long-term unfavorable effects.

Bacteroides fragilis derived metabolites, identified by molecular networking, decrease Salmonella virulence in mice model

In the gut microbiota, resident bacteria prevent pathogens infection by producing specific metabolites. Among bacteria belonging to phylum Bacteroidota, we have previously shown that Bacteroides fragilis or its cell-free supernatant inhibited in vitro Salmonella Heidelberg translocation. In the present study, we have analyzed this supernatant to identify bioactive molecules after extraction and subsequent fractionation using a semi-preparative reversed-phase Liquid Chromatography High-Resolution Tandem Mass Spectrometry (LC-HRMS/MS). The results indicated that only two fractions (F3 and F4) strongly inhibited S. Heidelberg translocation in a model mimicking the intestinal epithelium. The efficiency of the bioactive fractions was evaluated in BALB/c mice, and the results showed a decrease of S. Heidelberg in Peyer’s patches and spleen, associated with a decrease in inflammatory cytokines and neutrophils infiltration. The reduction of the genus Alistipes in mice receiving the fractions could be related to the anti-inflammatory effects of bioactive fractions. Furthermore, these bioactive fractions did not alter the gut microbiota diversity in mice. To further characterize the compounds present in these bioactive fractions, Liquid Chromatography High-Resolution Tandem Mass Spectrometry (LC-HRMS/MS) data were analyzed through molecular networking, highlighting cholic acid (CA) and deoxycholic acid. In vitro, CA had inhibitory activity against the translocation of S. Heidelberg by significantly decreasing the expression of Salmonella virulence genes such as sipA. The bioactive fractions also significantly downregulated the flagellar gene fliC, suggesting the involvement of other active molecules. This study showed the interest to characterize better the metabolites produced by B. fragilis to make them means of fighting pathogenic bacteria by targeting their virulence factor without modifying the gut microbiota.

Female reproductive dysfunctions and the gut microbiota

The gut microbiome is considered an endocrine organ that can influence distant organs and associated biological pathways. Recent advances suggest that gut microbial homeostasis is essential for reproductive health and that perturbations in the gut microbiota can lead to reproductive pathologies. This review provides an updated overview of the relationship between the gut microbiome and female reproductive diseases. Specifically, we highlight the most recent findings on the gut microbiome in gynecological pathologies including polycystic ovarian syndrome, endometriosis, and endometrial cancer. Most studies revealed associations between altered gut microbial compositions and these reproductive diseases, though few have suggested cause-effect relationships. Future studies should focus on determining the molecular mechanisms underlying associations between gut microbiota and reproductive diseases. Understanding this bidirectional relationship could lead to the development of novel and effective strategies to prevent, diagnose, and treat female reproductive organ-related diseases.

Lower abundance of Bacteroides and metabolic dysfunction are highly associated with the post-weaning diarrhea in piglets

Growing evidences show a direct link between diarrhea and disorders of gut microbiota in pigs. However, whether there are microbial markers associated with post-weaning diarrhea remains unknown. In the current study, we compared the microbial community, functions and metabolites between healthy weaned piglets (group H, n=7) and piglets with post-weaning diarrhea (group D, n=7), in order to find out diarrhea associated microbial markers. Each of 7 fecal samples was collected from H and D piglets (weaned at 21 d and sampled at 26 d). The metagenomic and untargeted metabolomic analysis revealed that the microbial composition, function and metabolic profile in D pigs was considerably reshaped, including the reduced abundance and number of Bacteroides, which significantly correlated with the diarrhea status of host. The carbohydrate metabolism, biosynthesis and metabolism, lipid metabolism, amino acid metabolism, and the activity of glycan and carbohydrates digestion related enzymes showed extensively down-regulated in D pigs compared with H pigs. Diarrhea significantly changed the metabolic profiles of fecal microbiota, and most of the altered metabolites were negatively or positively correlated with the change in the abundance of Bacteroides. In conclusion, the lower abundance of Bacteroides and its associated metabolic dysfunction may be regarded as microbial markers of physiological post-weaning diarrhea in piglets.

Diet-microbiome-gut-brain nexus in acute and chronic brain injury

In recent years, appreciation for the gut microbiome and its relationship to human health has emerged as a facilitator of maintaining healthy physiology and a contributor to numerous human diseases. The contribution of the microbiome in modulating the gut-brain axis has gained significant attention in recent years, extensively studied in chronic brain injuries such as Epilepsy and Alzheimer’s Disease. Furthermore, there is growing evidence that gut microbiome also contributes to acute brain injuries like stroke(s) and traumatic brain injury. Microbiome-gut-brain communications are bidirectional and involve metabolite production and modulation of immune and neuronal functions. The microbiome plays two distinct roles: it beneficially modulates immune system and neuronal functions; however, abnormalities in the host’s microbiome also exacerbates neuronal damage or delays the recovery from acute injuries. After brain injury, several inflammatory changes, such as the necrosis and apoptosis of neuronal tissue, propagates downward inflammatory signals to disrupt the microbiome homeostasis; however, microbiome dysbiosis impacts the upward signaling to the brain and interferes with recovery in neuronal functions and brain health. Diet is a superlative modulator of microbiome and is known to impact the gut-brain axis, including its influence on acute and neuronal injuries. In this review, we discussed the differential microbiome changes in both acute and chronic brain injuries, as well as the therapeutic importance of modulation by diets and probiotics. We emphasize the mechanistic studies based on animal models and their translational or clinical relationship by reviewing human studies.

Bidirectional crosstalk between dysbiotic gut microbiota and systemic lupus erythematosus: What is new in therapeutic approaches?

Systemic lupus erythematosus is an autoimmune disease characterized by chronic inflammation and multiple organs damage. Its pathogenesis is complex and involves multiple factors including gut microbiota. Accumulating evidence indicates the interaction of microbial communities with the host immune system to maintain a state of homeostasis. Imbalances within the gut microbial composition and function may contribute to the development of many autoimmune diseases including SLE. In this review, we aim to highlight the dysregulation of commensal bacteria and their metabolites in the gastrointestinal tract and the resulting autoimmune responses in lupus and to decrypt the cross-link between the altered gut microbiota and the immune system in the SLE condition. We also provide new insights into targeting gut microbiota as a promising therapeutic approach to treat and manage SLE.

Role of Intestinal Dysbiosis and Nutrition in Rheumatoid Arthritis

Rheumatoid arthritis is a chronic systemic immune-mediated disease caused by genetic and environmental factors. It is often characterized by the generation of autoantibodies that lead to synovial inflammation and eventual multi-joint destruction. A growing number of studies have shown significant differences in the gut microbiota composition of rheumatoid arthritis (RA) patients compared to healthy controls. Environmental factors, and changes in diet and nutrition are thought to play a role in developing this dysbiosis. This review aims to summarize the current knowledge of intestinal dysbiosis, the role of nutritional factors, and its implications in the pathogenesis of rheumatoid arthritis and autoimmunity. The future direction focuses on developing microbiome manipulation therapeutics for RA disease management.

Targeted suppression of human IBD-associated gut microbiota commensals by phage consortia for treatment of intestinal inflammation

Human gut commensals are increasingly suggested to impact non-communicable diseases, such as inflammatory bowel diseases (IBD), yet their targeted suppression remains a daunting unmet challenge. In four geographically distinct IBD cohorts (n = 537), we identify a clade of Klebsiella pneumoniae (Kp) strains, featuring a unique antibiotics resistance and mobilome signature, to be strongly associated with disease exacerbation and severity. Transfer of clinical IBD-associated Kp strains into colitis-prone, germ-free, and colonized mice enhances intestinal inflammation. Stepwise generation of a lytic five-phage combination, targeting sensitive and resistant IBD-associated Kp clade members through distinct mechanisms, enables effective Kp suppression in colitis-prone mice, driving an attenuated inflammation and disease severity. Proof-of-concept assessment of Kp-targeting phages in an artificial human gut and in healthy volunteers demonstrates gastric acid-dependent phage resilience, safety, and viability in the lower gut. Collectively, we demonstrate the feasibility of orally administered combination phage therapy in avoiding resistance, while effectively inhibiting non-communicable disease-contributing pathobionts.

Influences of Gastrointestinal Microbiota Dysbiosis on Serum Proinflammatory Markers in Epithelial Ovarian Cancer Development and Progression

GI microbiota has been implicated in producing the inflammatory tumor microenvironment of several cancers. Women with ovarian cancer often report GI-related symptoms at diagnosis although minimal is known about the possible GI bacteria that may trigger pro-tumorigenic immune responses in early EOC. The purpose of this study was to investigate the influences of GI microbiota dysbiosis on serum inflammatory markers during EOC utilizing a rodent model. This experimental design consisted of C57BL/6 mice randomly assigned to either the microbiota dysbiosis group (n = 6) or control group (n = 5). The CD7BL/6 mice assigned to the microbiota dysbiosis group were administered a mixture of broad-spectrum antibiotics (bacitracin and neomycin) for 2 weeks. Both groups were injected intraperitoneally with mouse ovarian epithelial cells that induce ovarian tumorigenesis. Levels of C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) were assessed in the serum, and the composition of the GI microbiota in fecal samples was measured using 16S rRNA gene sequencing. Overall CRP serum levels were significantly lower and TNFα levels were significantly higher in the microbiota dysbiosis group compared to the control group. The abundances of microbiota that correlated with CRP serum levels in the combined groups were genus Parabacteroides, Roseburia, and Emergencia and species Ruminococcus faecis, Parabacteroides distasonis, Roseburia Faecis, and Emergencia timonensis. This study provides evidence to support for further investigation of the GI microbial profiles in patients at risk of EOC.

Multimodal Imaging Mass Spectrometry of Murine Gastrointestinal Tract with Retained Luminal Content

The gastrointestinal tract, including luminal content, harbors a complex mixture of microorganisms, host dietary content, and immune factors. Existing imaging approaches remove luminal content and only visualize small regions of the GI tract. Here, we demonstrate a workflow for multimodal imaging using matrix-assisted laser desorption/ionization imaging mass spectrometry, autofluorescence, and bright field microscopy for mapping intestinal tissue and luminal content. Results comparing tissue and luminal content in control murine tissue show both unique molecular and elemental distributions and abundances using multimodal protein, lipid, and elemental imaging. For instance, lipid PC(42:1) is 2× higher intensity in luminal content than tissue, while PC(32:0) is 80× higher intensity in tissue. Additionally, some ions such as the protein at m/z 3443 and the element manganese are only detected in luminal content, while the protein at m/z 8564 was only detected in tissue and phosphorus had 2× higher abundance in tissue. These data highlight the robust molecular information that can be gained from the gastrointestinal tract with the inclusion of luminal content.

Inhibitory Bacterial Diversity and Mucosome Function Differentiate Susceptibility of Appalachian Salamanders to Chytrid Fungal Infection

Mucosal defenses are crucial in animals for protection against pathogens and predators. Host defense peptides (antimicrobial peptides, AMPs) as well as skin-associated microbes are key components of mucosal immunity, particularly in amphibians. We integrate microbiology, molecular biology, network-thinking, and proteomics to understand how host and microbially derived products on amphibian skin (referred to as the mucosome) serve as pathogen defenses. We studied defense mechanisms against chytrid pathogens, Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal), in four salamander species with different Batrachochytrium susceptibilities. Bd infection was quantified using qPCR, mucosome function (i.e., ability to kill Bd or Bsal zoospores in vitro), skin bacterial communities using 16S rRNA gene amplicon sequencing, and the role of Bd-inhibitory bacteria in microbial networks across all species. We explored the presence of candidate-AMPs in eastern newts and red-backed salamanders. Eastern newts had the highest Bd prevalence and mucosome function, while red-back salamanders had the lowest Bd prevalence and mucosome function, and two-lined salamanders and seal salamanders were intermediates. Salamanders with highest Bd infection intensity showed greater mucosome function. Bd infection prevalence significantly decreased as putative Bd-inhibitory bacterial richness and relative abundance increased on hosts. In co-occurrence networks, some putative Bd-inhibitory bacteria were found as hub-taxa, with red-backs having the highest proportion of protective hubs and positive associations related to putative Bd-inhibitory hub bacteria. We found more AMP candidates on salamanders with lower Bd susceptibility. These findings suggest that salamanders possess distinct innate mechanisms that affect chytrid fungi. IMPORTANCE How host mucosal defenses interact, and influence disease outcome is critical in understanding host defenses against pathogens. A more detailed understanding is needed of the interactions between the host and the functioning of its mucosal defenses in pathogen defense. This study investigates the variability of chytrid susceptibility in salamanders and the innate defenses each species possesses to mediate pathogens, thus advancing the knowledge toward a deeper understanding of the microbial ecology of skin-associated bacteria and contributing to the development of bioaugmentation strategies to mediate pathogen infection and disease. This study improves the understanding of complex immune defense mechanisms in salamanders and highlights the potential role of the mucosome to reduce the probability of Bd disease development and that putative protective bacteria may reduce likelihood of Bd infecting skin.

Lactococcus cremoris subsp. cremoris FC-fermented milk activates protein synthesis and increases skeletal muscle mass in middle-aged mice

Age-related muscle atrophy is associated with decreased protein anabolic capacity. Dietary intervention is an important strategy for the treatment of age-related muscle atrophy. This study examined the effect of Lactococcus cremoris subsp. cremoris FC-fermented milk on muscle mass and protein anabolic signaling in middle-aged mice. Male C57BL/6J mice (18-month-old) were divided into the control and Lactococcus cremoris subsp. cremoris FC-fermented milk supplementation groups. Mice were administered unfermented or fermented milk (300 μL/day) by gavage every alternate day for 8 weeks; thereafter, muscle weight, protein metabolic signaling factors, and inflammatory factors were investigated. Soleus muscle weight was higher in the fermented milk group than in the control group. Expression of insulin growth factor-1, a typical anabolic factor, and phosphorylation levels of anabolic signaling factors (mTOR and p70S6K) were higher after fermented milk supplementation. Levels of tumor necrosis factor-α, an inhibitor of protein anabolism, were lower in the fermented milk group. These data suggest that the daily intake of Lactococcus cremoris subsp. cremoris FC-fermented milk increased skeletal muscle mass as well as protein synthesis in the middle-aged mice, which may be mediated by reduction in the levels of inflammatory factors. Therefore, accelerated protein synthesis, induced by the consumption of fermented milk, has a potential role in counteracting muscle atrophy.

Effects of a mediterranean diet on the gut microbiota and microbial metabolites: A systematic review of randomized controlled trials and observational studies

Consumption of the Mediterranean dietary pattern (MedDiet) is associated with reduced risk of numerous non-communicable diseases. Modulation of the composition and metabolism of the gut microbiota represents a potential mechanism through which the MedDiet elicits these effects. We conducted a systematic literature search (Prospero registration: CRD42020168977) using PubMed, The Cochrane Library, MEDLINE, SPORTDiscuss, Scopus and CINAHL databases for randomized controlled trials (RCTs) and observational studies exploring the impact of a MedDiet on gut microbiota composition (i.e., relative abundance of bacteria or diversity metrics) and metabolites (e.g., short chain fatty acids). Seventeen RCTs and 17 observational studies were eligible for inclusion in this review. Risk of bias across the studies was mixed but mainly identified as low and unclear. Overall, RCTs and observational studies provided no clear evidence of a consistent effect of a MedDiet on composition or metabolism of the gut microbiota. These findings may be related to the diverse methods across studies (e.g., MedDiet classification and analytical techniques), cohort characteristics, and variable quality of studies. Further, well-designed studies are warranted to advance understanding of the potential effects of the MedDiet using more detailed examination of microbiota and microbial metabolites with reference to emerging characteristics of a healthy gut microbiome.

Microbial Metabolite Regulation of Epithelial Cell-Cell Interactions and Barrier Function

Epithelial cells that line tissues such as the intestine serve as the primary barrier to the outside world. Epithelia provide selective permeability in the presence of a large constellation of microbes, termed the microbiota. Recent studies have revealed that the symbiotic relationship between the healthy host and the microbiota includes the regulation of cell–cell interactions at the level of epithelial tight junctions. The most recent findings have identified multiple microbial-derived metabolites that influence intracellular signaling pathways which elicit activities at the epithelial apical junction complex. Here, we review recent findings that place microbiota-derived metabolites as primary regulators of epithelial cell–cell interactions and ultimately mucosal permeability in health and disease.

Gut Microbiota and Their Metabolites in Stroke: A Double-Edged Sword

Besides damaging the brain, stroke causes systemic changes, including to the gastrointestinal system. A growing body of evidence supports the role of the gut and its microbiota in stroke, stroke prognosis, and recovery. The gut microbiota can increase the risk of a cerebrovascular event, playing a role in the onset of stroke. Conversely, stroke can induce dysbiosis of the gut microbiota and epithelial barrier integrity. This has been proposed as a contributor to systemic infections. In this review, we describe the role of the gut microbiota, microbiome and microbiota-derived metabolites in experimental and clinical stroke, and their potential use as therapeutic targets. Fourteen clinical studies have identified 62 upregulated (eg, Streptococcus, Lactobacillus, Escherichia) and 29 downregulated microbial taxa (eg, Eubacterium, Roseburia) between stroke and healthy participants. The majority found that stroke patients have reduced gut microbiome diversity. However, other nonbacterial microorganisms are yet to be studied. In experimental stroke, severity is dependent on gut microbiome composition, whereas the latter can greatly change with antibiotics, age, and diet. Consumption of foods rich in choline and L-carnitine are positively associated with stroke onset via production of trimethylamine N-oxide in experimental and clinical stroke. Conversely, in mice, consumption of dietary fiber improves stroke outcome, likely via gut microbiota-derived metabolites called short-chain fatty acids, such as acetate, propionate, and butyrate. The majority of the evidence, however, comes from experimental studies. Clinical interventions targeted at gut microbiota-derived metabolites as new therapeutic opportunities for stroke prevention and treatment are warranted.

Bacterial Gut Microbiota and Infections During Early Childhood

Gut microbiota composition during the first years of life is variable, dynamic and influenced by both prenatal and postnatal factors, such as maternal antibiotics administered during labor, delivery mode, maternal diet, breastfeeding, and/or antibiotic consumption during infancy. Furthermore, the microbiota displays bidirectional interactions with infectious agents, either through direct microbiota-microorganism interactions or indirectly through various stimuli of the host immune system. Here we review these interactions during childhood until 5 years of life, focusing on bacterial microbiota, the most common gastrointestinal and respiratory infections and two well characterized gastrointestinal diseases related to dysbiosis (necrotizing enterocolitis and Clostridioides difficile infection). To date, most peer-reviewed studies on the bacterial microbiota in childhood have been cross-sectional and have reported patterns of gut dysbiosis during infections as compared to healthy controls; prospective studies suggest that most children progressively return to a "healthy microbiota status" following infection. Animal models and/or studies focusing on specific preventive and therapeutic interventions, such as probiotic administration and fecal transplantation, support the role of the bacterial gut microbiota in modulating both enteric and respiratory infections. A more in depth understanding of the mechanisms involved in the establishment and maintenance of the early bacterial microbiota, focusing on specific components of the microbiota-immunity-infectious agent axis is necessary in order to better define potential preventive or therapeutic tools against significant infections in children.

Human milk oligosaccharides and infant gut microbiota: Molecular structures, utilization strategies and immune function

Human milk oligosaccharides (HMOs) are a unique class of non-digestible carbohydrates present in the mother milk, which play a key role in the development of infant gut microbiota, epithelial barrier and immune function. The deficiency of HMOs in the bovine milk-based infant formula has been widely recognized as a major culprit for the much higher incidence of immune disorders of formula-fed infants. This report was to give an up-to-date review on the structure characteristics of HMOs and the possible mechanisms, and strategies for their cellular uptake, and metabolism by the gut bacteria and the associated effects on the infant gut microbiome, and immune function. Most previous studies have been carried out in animals or in vitro model systems on the utilization strategies for HMOs in infant bacteria and their roles in infant microbiome, and gut immune function. A few HMO molecules have been synthesized artificially and applied in infant formulas.

Yeast β-Glucan Altered Intestinal Microbiome and Metabolome in Older Hens

The prebiotics- and probiotics-mediated positive modulation of the gut microbiota composition is considered a useful approach to improve gut health and food safety in chickens. This study explored the effects of yeast β-glucan (YG) supplementation on intestinal microbiome and metabolites profiles as well as mucosal immunity in older hens. A total of 256 43-week-old hens were randomly assigned to two treatments, with 0 and 200 mg/kg of YG. Results revealed YG-induced downregulation of toll-like receptors (TLRs) and cytokine gene expression in the ileum without any effect on the intestinal barrier. 16S rRNA analysis claimed that YG altered α- and β-diversity and enriched the relative abundance of class Bacilli, orders Lactobacillales and Enterobacteriales, families Lactobacillaceae and Enterobacteriaceae, genera Lactobacillus and Escherichia–Shigella, and species uncultured bacterium-Lactobacillus. Significant downregulation of cutin and suberin, wax biosynthesis, atrazine degradation, vitamin B6 metabolism, phosphotransferase system (PTS), steroid degradation, biosynthesis of unsaturated fatty acids, aminobenzoate degradation and quorum sensing and upregulation of ascorbate and aldarate metabolism, C5-branched dibasic acid metabolism, glyoxylate and dicarboxylate metabolism, pentose and glucuronate interconversions, steroid biosynthesis, carotenoid biosynthesis, porphyrin and chlorophyll metabolism, sesquiterpenoid and triterpenoid biosynthesis, lysine degradation, and ubiquinone and other terpenoid-quinone biosyntheses were observed in YG-treated hens, as substantiated by the findings of untargeted metabolomics analysis. Overall, YG manifests prebiotic properties by altering gut microbiome and metabolite profiles and can downregulate the intestinal mucosal immune response of breeder hens.

Metagenomic and metatranscriptomic analyses reveal minor-yet-crucial roles of gut microbiome in deep-sea hydrothermal vent snail

BACKGROUND

Marine animals often exhibit complex symbiotic relationship with gut microbes to attain better use of the available resources. Many animals endemic to deep-sea chemosynthetic ecosystems host chemoautotrophic bacteria endocellularly, and they are thought to rely entirely on these symbionts for energy and nutrition. Numerous investigations have been conducted on the interdependence between these animal hosts and their chemoautotrophic symbionts. The provannid snail Alviniconcha marisindica from the Indian Ocean hydrothermal vent fields hosts a Campylobacterial endosymbiont in its gill. Unlike many other chemosymbiotic animals, the gut of A. marisindica is reduced but remains functional; yet the contribution of gut microbiomes and their interactions with the host remain poorly characterised.

RESULTS

Metagenomic and metatranscriptomic analyses showed that the gut microbiome of A. marisindica plays key nutritional and metabolic roles. The composition and relative abundance of gut microbiota of A. marisindica were different from those of snails that do not depend on endosymbiosis. The relative abundance of microbial taxa was similar amongst three individuals of A. marisindica with significant inter-taxa correlations. These correlations suggest the potential for interactions between taxa that may influence community assembly and stability. Functional profiles of the gut microbiome revealed thousands of additional genes that assist in the use of vent-supplied inorganic compounds (autotrophic energy source), digest host-ingested organics (carbon source), and recycle the metabolic waste of the host. In addition, members of five taxonomic classes have the potential to form slime capsules to protect themselves from the host immune system, thereby contributing to homeostasis. Gut microbial ecology and its interplay with the host thus contribute to the nutritional and metabolic demands of A. marisindica.

CONCLUSIONS

The findings advance the understanding of how deep-sea chemosymbiotic animals use available resources through contributions from gut microbiota. Gut microbiota may be critical in the survival of invertebrate hosts with autotrophic endosymbionts in extreme environments.

Deoxycholic acid delays the wound healing of colonic epithelial cells via transmembrane G-protein-coupled receptor 5

BACKGROUND AND AIM

Efficient intestinal wound healing is essential for good prognoses of ulcerative colitis (UC). Although bile acids and the transmembrane G-protein-coupled receptor (TGR) 5 have been reported to affect wound healing in intestinal epithelial cells, the detailed underlying mechanisms are unclear. Here, we investigated the role of TGR5 in wound healing in the context of colonic epithelial cells in the presence of bile acids.

METHODS

The expression of TGR5 in the colonic epithelium of both a dextran sulfate sodium (DSS)-induced colitis mouse model (recovery phase), and UC patients in clinical remission, was evaluated. Young adult mouse colonic epithelial (YAMC) cells were then used to evaluate wound healing after treatment with deoxycholic acid (DCA); TGR5 was silenced in YAMC cells via shRNA-transfection, and a wound-healing assay in the presence of DCA was performed. Furthermore, we investigated the role of the activation of AKT in the context of wound healing.

RESULTS

The expression of TGR5 was decreased in the colonic epithelium of both mice with DSS-induced colitis and UC patients. Additionally, DCA significantly delayed wound healing in YAMC cells but not in TGR5 silenced ones. Of note, the DCA-induced activation of AKT signaling in YAMC cells was inhibited by TGR5 silencing, and AKT inhibitors prevented the wound healing delay induced by DCA.

CONCLUSIONS

Overall, we show that DCA delays wound healing in the context of colonic epithelial cells through AKT activation. These results may support the development of new therapeutic approaches for epithelial regeneration in UC.

Next-generation microbial drugs developed from microbiome's natural products

Scientists working in natural products chemistry have been enticed by the current advancements being made in the discovery of novel "magic bullets" from microbes homed to all conceivable environments. Even though researchers continue to face challenges funneling the novel bioactive compounds in the global therapeutic industries, it seems most likely that the discovery of some "hit molecules" with significant biomedical applications is not that far. We applaud novel natural products for their ability to combat the spread of superbugs and aid in the prevention of currently observed antibiotic resistance. This in-depth investigation covers a wide range of microbiomes with a proclivity for synthesizing novel compounds to combat the spread of superbugs. Furthermore, we use this opportunity to explore various groups of secondary metabolites and their biosynthetic pathways in various microbiota found in mammals, insects, and humans. This systematic study, when taken as a whole, offers detail understanding on the biomedical fate of various groups of compounds originated from diverse microbiomes. For gathering all information that has been uncovered and released so far, we have also presented the huge diversity of microbes that are associated with humans and their metabolic products. To conclude, this concrete review suggests novel ideas that will prove immensely helpful in reducing the danger posed by superbugs while also improving the efficacy of antibiotics.

Dual role of microbiota-derived short-chain fatty acids on host and pathogen

A growing body of documents shows microbiota produce metabolites such as short-chain fatty acids (SCFAs) as crucial executors of diet-based microbial influence the host and bacterial pathogens. The production of SCFAs depends on the metabolic activity of intestinal microflora and is also affected by dietary changes. SCFAs play important roles in maintaining colonic health as an energy source, as a regulator of gene expression and cell differentiation, and as an anti-inflammatory agent. Additionally, the regulated expression of virulence genes is critical for successful infection by an intestinal pathogen. Bacteria rely on sensing environmental signals to find preferable niches and reach the infectious state. This review will present data supporting the diverse functional roles of microbiota-derived butyrate, propionate, and acetate on host cellular activities such as immune modulation, energy metabolism, nervous system, inflammation, cellular differentiation, and anti-tumor effects, among others. On the other hand, we will discuss and summarize data about the role of these SCFAs on the virulence factor of bacterial pathogens. In this regard, receptors and signaling routes for SCFAs metabolites in host and pathogens will be introduced.

A non-optimal cervicovaginal microbiota in pregnancy is associated with a distinct metabolomic signature among non-Hispanic Black individuals

Biomechanical and molecular processes of premature cervical remodeling preceding spontaneous preterm birth (sPTB) likely result from interactions between the cervicovaginal microbiota and host immune responses. A non-optimal cervicovaginal microbiota confers increased risk of sPTB. The cervicovaginal space is metabolically active in pregancy; microbiota can produce, modify, and degrade metabolites within this ecosystem. We establish that cervicovaginal metabolomic output clusters by microbial community in pregnancy among Black individuals, revealing increased metabolism within the amino acid and dipeptide pathways as hallmarks of a non-optimal microbiota. Few differences were detected in metabolomic profiles when stratified by birth outcome. The study raises the possibility that metabolites could distinguish women with greater risk of sPTB among those with similar cervicovaginal microbiota, and that metabolites within the amino acid and carbohydrate pathways may play a role in this distinction.

Probiotics Treatment of Leg Diseases in Broiler Chickens: a Review

Normal development and growth of bones are critical for poultry. With the rapid growth experienced by broiler chickens, higher incidences of leg weakness and lameness are common problems in adolescent meat-type poultry that present huge economic and welfare issues. Leg disorders such as angular bone deformities and tibial dyschondroplasia have become common in broilers and are associated with poor growth, high mortality rates, increased carcass condemnation, and downgrading at slaughter. Probiotics have shown promise for a variety of health purposes, including preventing diarrhea, elevating carcass quality, and promoting growth of the poultry. In addition, recent studies have indicated that probiotics can maintain the homeostasis of the gut microbiota and improve the health of the gastrointestinal tract, which confers a potentially beneficial effect on bone health. This review mainly describes the occurrence of broiler leg disease and the role of probiotics in bone health through regulating the gut microbiota and improving intestinal function, thus providing a relevant theoretical basis for probiotics to hinder the development of skeletal disorders in broiler chickens.

Probiotic Pediococcus pentosaceus ABY 118 to Modulation of ChIFN-γ and ChIL-10 in Broilers Infected by Eimeria tenella Oocyst

Eimeria causes coccidiosis, which has long been recognized as a disease in chickens that significantly affects the economy. The global chicken population continues to grow, and its contribution to food security increases, making it increasingly important to produce chicken meat that is safe for human and health. This study aims to prove Pediococcus pentosaceus ABY 118 to modulation of ChIFN-γ and ChIL-10 in chickens infected with E. tenella oocysts. This study used 100 of day-old chickens (DOC), randomly divided into 5 treatments; each treatment consists of 20 chickens. The treatments was as follows: P0 (−): negative control; P0 (+): positive control; P1: monensin; P2: probiotic 1.5 × 10⁸ CFU/ml; and P3: probiotic 3.0 × 10⁸ CFU/ml. At the age of 20 days, Eimeria tenella (E. tenella) oocysts were inoculated orally at a dose of 1 × 10⁴. The probiotic P. pentosaceus ABY 118 was given orally through drinking water from DOC to 35 days. Monensin was given orally through feed from the age of 14–26 days. The results of statistical analysis showed that there was a significant difference (P < 0.05) between treatments on ChIFN-γ and ChIL-10 at 6 and 8 days postinfected with E. tenella oocysts. Based on the results of this study, it can be concluded that the use of P. pentosaceus ABY 118 isolates at a dose of 1.5 × 10⁸ CFU/ml and 3.0 × 10⁸ CFU/ml per liter of drinking water can increase health by stimulation of ChIFN-γ and ChIL-10 in broiler infected with E. tenella oocyst.

Epigenome - A mediator for host-microbiome crosstalk

The interaction between the gut and its eventual trillions of microbe inhabitants during microbial colonization, represents a critical time period for establishing the overall health and wellbeing of an individual. The gut microbiome represents a diverse community of microbes that are critical for many physiological roles of the host including host metabolism. These processes are controlled by a fine-tuned chemical cross talk between the host and microbiota. Although the exact mechanisms behind this cross talk remains elusive, microbiota induced epigenetic mechanisms like DNA methylation and histone modifications may be key. This review presents our perspective on the epigenome as a mediator for host-microbiota cross talk, as well as methodology to study epigenetics, the role of dysbiosis in disease, and how the gut microbiome-host axis may be used in personal medicine.

Gut microbiota-derived short-chain fatty acids protect against the progression of endometriosis

Worldwide, ∼196 million are afflicted with endometriosis, a painful disease in which endometrial tissue implants and proliferates on abdominal peritoneal surfaces. Theories on the origin of endometriosis remained inconclusive. Whereas up to 90% of women experience retrograde menstruation, only 10% develop endometriosis, suggesting that factors that alter peritoneal environment might contribute to endometriosis. Herein, we report that whereas some gut bacteria promote endometriosis, others protect against endometriosis by fermenting fiber to produce short-chain fatty acids. Specifically, we found that altered gut microbiota drives endometriotic lesion growth and feces from mice with endometriosis contained less of short-chain fatty acid and n-butyrate than feces from mice without endometriosis. Treatment with n-butyrate reduced growth of both mouse endometriotic lesions and human endometriotic lesions in a pre-clinical mouse model. Mechanistic studies revealed that n-butyrate inhibited human endometriotic cell survival and lesion growth through G-protein-coupled receptors, histone deacetylases, and a GTPase activating protein, RAP1GAP. Our findings will enable future studies aimed at developing diagnostic tests, gut bacteria metabolites and treatment strategies, dietary supplements, n-butyrate analogs, or probiotics for endometriosis.

Effects of oral administration of timothy hay and psyllium on the growth performance and fecal microbiota of preweaning calves

The objective of this study was to evaluate the effects of oral administration of fiber from the first week of life on the growth and hindgut environment of preweaning calves. Twenty newborn female Holstein calves were divided into 2 groups as control and treatment. Calves in both groups were reared under the same feeding program except for oral fiber administration. Timothy hay and psyllium were mixed at a 50-to-6 ratio as a treatment diet for oral fiber administration. Calves in the treatment group were orally administered 50 g of fiber daily from 3 to 7 d of age and 100 g of fiber from 8 d of age until weaning. Feed intake and occurrence of diarrhea were recorded daily, and body weight (BW) was recorded weekly for the individual calf. Fresh feces were collected from calves at 7, 21, 35, 49, and 56 d of age to analyze fermentation parameters and microbiota to characterize the hindgut environment. Higher fiber intake in the treatment group due to oral administration of timothy and psyllium did not affect the starter intake and achieved higher BW at 21 d of age. The fecal pH, total volatile fatty acid, lactate, and ammonia nitrogen concentrations were not affected by oral fiber administration; meanwhile, the molar proportion of propionate was higher in the treatment group at 7 d of age. The difference in fecal microbiota in the calves subjected to the oral administration of fiber was observed within 21 d of life; Lactobacillus spp. and Prevotella spp. showed higher abundance, whereas that of Clostridium perfringens was decreased. These higher abundances of beneficial bacteria and lower abundance of pathogenic bacteria during early life may partly explain the higher BW of calves in the treatment group at 21 d of age. Furthermore, no adverse effect was observed for the BW and health status in the treatment group throughout the preweaning period. Therefore, early fiber feeding via oral administration potentially contributes to improving the hindgut environment in newborn calves, which leads to better growth of calves during the early stage of life.

Algal Oil Rich in Docosahexaenoic Acid Alleviates Intestinal Inflammation Induced by Antibiotics Associated with the Modulation of the Gut Microbiome and Metabolome

In this study, the effect of algal oil rich in docosahexaenoic acid on the mucosal injury with gut microbiota disorders caused by ceftriaxone sodium (CS) was evaluated. The results showed that algal oil treatment (500 mg kg^-1 day^-1) significantly reduced the levels of pro-inflammatory cytokines, including interleukin 6 , interleukin 1β, and tumor necrosis factor α, in the colon. Algal oil restored the CS-induced gut microbiota dysbiosis by elevating some short-chain-fatty-acid-producing bacteria, e.g., Ruminococcus and Blautia. The CS-induced metabolic disorder was also regulated by algal oil, which was characterized by the modulations of tryptophan metabolism, phospholipid metabolism, and bile acid metabolism. Our results suggested that supplementation of algal oil could alleviate inflammation and promote mucosal healing, which could be a functional food ingredient to protect aganist antibiotic-induced alteration of gut microbiota and metabolic dysbiosis.

The Vibrio cholerae Type Six Secretion System Is Dispensable for Colonization but Affects Pathogenesis and the Structure of Zebrafish Intestinal Microbiome

Zebrafish (Danio rerio) are an attractive model organism for a variety of scientific studies, including host-microbe interactions. The organism is particularly useful for the study of aquatic microbes that can colonize vertebrate hosts, including Vibrio cholerae, an intestinal pathogen. V. cholerae must colonize the intestine of an exposed host for pathogenicity to occur. While numerous studies have explored various aspects of the pathogenic effects of V. cholerae on zebrafish and other model organisms, few, if any, have examined how a V. cholerae infection alters the resident intestinal microbiome and the role of the type six secretion system (T6SS) in that process. In this study, 16S rRNA gene sequencing was utilized to investigate how strains of V. cholerae both with and without the T6SS alter the aforementioned microbial profiles following an infection. V. cholerae infection induced significant changes in the zebrafish intestinal microbiome, and while not necessary for colonization, the T6SS was important for inducing mucin secretion, a marker for diarrhea. Additional salient differences to the microbiome were observed based on the presence or absence of the T6SS in the V. cholerae utilized for challenging the zebrafish hosts. We conclude that V. cholerae significantly modulates the zebrafish intestinal microbiome to enable colonization and that the T6SS is important for pathogenesis induced by the examined V. cholerae strains. Furthermore, the presence or absence of T6SS differentially and significantly affected the composition and structure of the intestinal microbiome, with an increased abundance of other Vibrio bacteria observed in the absence of V. cholerae T6SS.