Manipulation Of Microbiota Research Articles

Variability in fecal metabolome depending on age, PFBS pollutant, and fecal transplantation in zebrafish: A non-invasive diagnosis of health

To protect the wellbeing of research animals, certain non-invasive measures are in increasing need to facilitate an early diagnosis of health and toxicity. In this study, feces specimen was collected from adult zebrafish to profile the metabolome fingerprint. Variability in fecal metabolite composition was also distinguished as a result of aging, perfluorobutanesulfonate (PFBS) toxicant, and fecal transplantation. The results showed that zebrafish feces was very rich in a diversity of metabolites that belonged to several major classes, including lipid, amino acid, carbohydrate, vitamin, steroid hormone, and neurotransmitter. Fecal metabolites had functional implications to multiple physiological activities, which were characterized by the enrichment of digestion, absorption, endocrine, and neurotransmission processes. The high richness and functional involvement of fecal metabolites pinpointed feces as an abundant source of diagnostic markers. By comparison between young and aged zebrafish, fundamental modifications of fecal metabolomes were caused by aging progression, centering on the neuroactive ligand-receptor interaction pathway. Exposure of aged zebrafish to PFBS pollutant also significantly disrupted the metabolomic structure in feces. Of special concern were the changes in fecal hormone intermediates after PFBS exposure, which was concordant with the in vivo endocrine disrupting effects of PFBS. Furthermore, it was intriguing that transplantation of young zebrafish feces efficiently mitigated the metabolic perturbation of PFBS in aged recipients, highlighting the health benefits of therapeutic strategies based on gut microbiota manipulation. In summary, the present study provides preliminary clues to evidence the non-invasive advantage of fecal metabolomics in the early diagnosis and prediction of physiology and toxicology.

Manipulation of Gut Microbiota as a Key Target for Crohn's Disease.

Crohn's disease (CD) is an inflammatory bowel disease (IBD) sub-type characterized by transmural chronic inflammation of the gastrointestinal tract. Research indicates a complex CD etiology involving genetic predisposition and immune dysregulation in response to environmental triggers. The chronic mucosal inflammation has been associated with a dysregulated state, or dysbiosis, of the gut microbiome (bacteria), mycobiome (fungi), virome (bacteriophages and viruses), and archeaome (archaea) further affecting the interkingdom syntrophic relationships and host metabolism. Microbiota dysbiosis in CD is largely described by an increase in facultative anaerobic pathobionts at the expense of strict anaerobic Firmicutes, such as Faecalibacterium prausnitzii. In the mycobiome, reduced fungal diversity and fungal-bacteria interactions, along with a significantly increased abundance of Candida spp. and a decrease in Saccharomyces cerevisiae are well documented. Virome analysis also indicates a significant decrease in phage diversity, but an overall increase in phages infecting bacterial groups associated with intestinal inflammation. Finally, an increase in methanogenic archaea such as Methanosphaera stadtmanae exhibits high immunogenic potential and is associated with CD etiology. Common anti-inflammatory medications used in CD management (amino-salicylates, immunomodulators, and biologics) could also directly or indirectly affect the gut microbiome in CD. Other medications often used concomitantly in IBD, such as antibiotics, antidepressants, oral contraceptives, opioids, and proton pump inhibitors, have shown to alter the gut microbiota and account for increased susceptibility to disease onset or worsening of disease progression. In contrast, some environmental modifications through alternative therapies including fecal microbiota transplant (FMT), diet and dietary supplements with prebiotics, probiotics, and synbiotics have shown potential protective effects by reversing microbiota dysbiosis or by directly promoting beneficial microbes, together with minimal long-term adverse effects. In this review, we discuss the different approaches to modulating the global consortium of bacteria, fungi, viruses, and archaea in patients with CD through therapies that include antibiotics, probiotics, prebiotics, synbiotics, personalized diets, and FMT. We hope to provide evidence to encourage clinicians and researchers to incorporate these therapies into CD treatment options, along with making them aware of the limitations of these therapies, and indicate where more research is needed.

The Role of Gut Microbiota in the Skeletal Muscle Development and Fat Deposition in Pigs.

Pork quality is a factor increasingly considered in consumer preferences for pork. The formation mechanisms determining meat quality are complicated, including endogenous and exogenous factors. Despite a lot of research on meat quality, unexpected variation in meat quality is still a major problem in the meat industry. Currently, gut microbiota and their metabolites have attracted increased attention in the animal breeding industry, and recent research demonstrated their significance in muscle fiber development and fat deposition. The purpose of this paper is to summarize the research on the effects of gut microbiota on pig muscle and fat deposition. The factors affecting gut microbiota composition will also be discussed, including host genetics, dietary composition, antibiotics, prebiotics, and probiotics. We provide an overall understanding of the relationship between gut microbiota and meat quality in pigs, and how manipulation of gut microbiota may contribute to increasing pork quality for human consumption.

Resilience or susceptibility to traumatic stress: Potential influence of the microbiome

Exposure to traumatic stress is a major risk factor for development of neuropsychiatric disorders in a sub-population of individuals, while others remain resilient. The mechanisms and contributing factors differentiating between these phenotypes are still unclear. We hypothesize that inter-individual differences in the microbial composition and function contribute to host resilience or susceptibility to stress-induced psychopathologies. The current study aimed to characterize gut microbial community before and after exposure to traumatic stress in an animal model of PTSD. Sprague-Dawley male rats were randomly divided into unstressed controls and experimental group subjected to Single Prolonged Stress (SPS). After 14 days, behavioral analyses were performed using Open Field, Social Interaction and Elevated Plus Maze tests. Based on the anxiety measures, the SPS group was further subdivided into resilient (SPS-R) and susceptible (SPS–S) cohorts. The animals were sacrificed after the last behavioral test and cecum, colon, hippocampus, and medial prefrontal cortex were dissected. Prior to SPS and immediately after Open Field test, fecal samples were collected from each rat for 16S V3–V4 ribosomal DNA sequencing, whereas urine samples were collected before SPS, 90 min into immobilization and on the day of sacrifice to measure epinephrine and norepinephrine levels. Analyses of the fecal microbiota revealed significant differences in microbial communities and in their predictive functionality among the groups before and after SPS stressors. Before SPS, the SPS-S subgroup harbored microbiota with an overall pro-inflammatory phenotype, whereas SPS-R subgroup had microbiota with an overall anti-inflammatory phenotype, with predictive functional pathways enriched in carbohydrate and lipid metabolism and decreased in amino acid metabolism and neurodegenerative diseases. After SPS, the gut microbial communities and their predictive functionality shifted especially in SPS cohorts, with volatility at the genus level correlating inversely with Anxiety Index. In line with the alterations seen in the gut microbiota, the levels of cecal short chain fatty acids were also altered, with SPS-S subgroup having significantly lower levels of acetate, valerate and caproate. The levels of acetate inversely correlated with Anxiety Index. Interestingly, urinary epinephrine and norepinephrine levels were also higher in the SPS-S subgroup at baseline and during stress, indicative of an altered sympathoadrenal stress axis. Finally, shorter colon (marker of intestinal inflammation) and a lower claudin-5 protein expression (marker for increased blood brain barrier permeability) were observed in the SPS-S subgroup. Taken together, our results suggest microbiota is a potential factor in predisposing subjects either to stress susceptibility or resilience. Moreover, SPS triggered significant shifts in the gut microbiota, their metabolites and brain permeability. These findings could lead to new therapeutic directions for PTSD possibly through the controlled manipulation of gut microbiota. It may enable early identification of individuals more likely to develop prolonged anxiogenic symptoms following traumatic stress.

Acrylamide induced glucose metabolism disorder in rats involves gut microbiota dysbiosis and changed bile acids metabolism

Acrylamide (AA) is a common food contaminant that causes glucose metabolism disorders (GMD). However, the underlying mechanism remains unclear. Female Sprague Dawley (SD) rats were treated with AA via gavage for 21 days, and the glucose and insulin levels, gut microbiota, intestinal barrier, and metabolism were analyzed. The results revealed that AA elevated serum glucose levels, reduced insulin levels and caused intestinal barrier injury. The 16S amplicon sequencing and non-targeted metabolomics showed that AA induced gut microbiota dysbiosis and bile acids (BAs) metabolism disorder. Specifically, AA decreased the abundance of Lactobacillus and Bacteroides in the cecal contents, and increased the cholic acid (CA) content in feces. Meanwhile, the expression of ileum apical sodium-dependent bile acid transporter (ASBT) responsible for CA reabsorption was suppressed. Further analysis indicated that BAs sensing nuclear receptor farnesoid X receptor (FXR) gene was activated and glucagon-like peptide-1 (GLP-1) which stimulates insulin secretion was downregulated. In addition, activation of FXR increased the expression of fibroblast growth factor 15 (FGF15), which resulted in the inhibition of hepatic BAs synthesis. Overall, this study demonstrated that AA-induced GMD is associated with the gut-microbiota-CA-FXR/GLP-1 axis. These findings add new knowledge to the AA-induced GMD and provide a basis for potential AA toxicity mitigation by manipulation of the gut microbiota.

Microbiota manipulation through the secretion of effector proteins is fundamental to the wealth of lifestyles in the fungal kingdom

Fungi are well-known decomposers of organic matter that thrive in virtually any environment on Earth where they encounter wealths of other microbes. Some fungi evolved symbiotic lifestyles, including pathogens and mutualists, that have mostly been studied in binary interactions with their hosts. However, we now appreciate that such interactions are greatly influenced by the ecological context in which they take place. While establishing their symbioses, fungi not only interact with their hosts but also with the host-associated microbiota. Thus, they target the host and its associated microbiota as a single holobiont. Recent studies have shown that fungal pathogens manipulate the host microbiota by means of secreted effector proteins with selective antimicrobial activity to stimulate disease development. In this review, we discuss the ecological contexts in which such effector-mediated microbiota manipulation is relevant for the fungal lifestyle and argue that this is not only relevant for pathogens of plants and animals but also beneficial in virtually any niche where fungi occur. Moreover, we reason that effector-mediated microbiota manipulation likely evolved already in fungal ancestors that encountered microbial competition long before symbiosis with land plants and mammalian animals evolved. Thus, we claim that effector-mediated microbiota manipulation is fundamental to fungal biology.

Protective effect of fermented okara on the regulation of inflammation, the gut microbiota, and SCFAs production in rats with TNBS-induced colitis

Dysbiosis of gut microbiota is intimately related to ulcerative colitis. The literature has revealed the gut microbiota metabolism of dietary fiber, which is a key resource for short-chain fatty acids (SCFAs) production and subsequently leads to anti-inflammatory effects. It is known that okara (a soybean byproduct) is rich in dietary fiber, but the effect of fermented okara on relieving colitis remains unclear. The object of this study was to investigate the effects of Aspergillus oryzae-fermented okara (FO) on colitis prevention through gut microbiota manipulation in a 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis rat model. The results showed that administration of FO elevated the relative abundance of SCFAs-producing bacteria (Lachnospiraceae and Bifidobacteriaceae) and SCFAs production, which engaged with GPR43 (SCFAs receptor) consequently decreased the production of proinflammatory cytokines (IL-6, IL-1β, and TNF-α), inflammatory mediators (COX-2, iNOS, PGE2, and NO), and MCP-1 chemokine and increased anti-inflammatory cytokine (IL-10 and IL-4) production through inhibition of HDAC3/MAPK-related proteins and the NF-κB inflammatory pathway in TNBS-induced colitis in rats. Moreover, increased activity of antioxidants, such as SOD, CAT, GSH, and GPx, and decreased MDA and MPO production were also observed after FO administration in TNBS-induced colitis in rats. This study demonstrated the novel potential of soybean byproducts for alleviating TNBS-induced intestinal inflammation and enhancing antioxidant capacity for colitis improvement. This new finding may enhance the value of okara for functional food development.

Human microbiota: A crucial gatekeeper in lung cancer initiation, progression, and treatment

Lung cancer is becoming one of the most detrimental cancers with the highest morbidity and mortality rate of all cancers, posing a significant burden for the global health system. Nonetheless, the therapeutic efficacy of traditional lung cancer therapies still remains relatively unsatisfying with varied responsiveness and unexpected adverse effects. Fortunately, studies have reported that an intimate relationship might exist between microbiota and lung carcinoma. Notably, microbial dysbiosis might result in changes in the metabolism, induction of immunosuppression, and recruitment of inflammatory factors, thereby driving lung carcinogenesis. Certain microbial strains were identified to be specifically enriched in the lung tumor beds, indicating their predictive role in lung cancer. Furthermore, the particular microbial composition was also proved to potentiate the outcomes of lung cancer therapies, suggesting that lung and gut microbiome were promising to be clinically applied for lung cancer therapy. In this review, we will comprehensively summarize the recent findings on how microbes mediate the initiation, progression, and treatment of lung cancer, illustrating the potential mechanisms and probing into the putative manipulation of microbiota to facilitate lung cancer treatments.

Gut-based manipulations spur hippocampal mitochondrial bioenergetics in a model of pediatric epilepsy

A growing body of evidence supports a role of the gut microbiota in regulating diverse physiological processes, including neural function and metabolism via the gut-brain axis. Infantile spasms syndrome is an early-onset epileptic encephalopathy associated with perturbed brain mitochondrial bioenergetics. Employing a neonatal rat model of infantile spasms, mitochondria respirometry and biochemical analyses, the present study reveals that gut microbiota manipulation by diet, antibiotics and probiotics have the potential to enhance hippocampal mitochondrial bioenergetics. Although preliminary in nature, our data reveal that microbial manipulation that regulates brain mitochondrial function may be a novel strategy for the treatment of epileptic disorders.

Alterations in Microbiota‐Gut‐Brain Axis and Susceptibility or Resilience to Traumatic Stress

Post‐Traumatic Stress Disorder (PTSD) is a severe and long‐lasting outcome of exposure to traumatic life event. Exposure to trauma induces PTSD only in a sub‐population of individuals while others remain resilient. The mechanisms and contributing factors differentiating between stress resilient and stress susceptible subjects are still unclear. We hypothesize that inter‐individual differences in the microbiome composition and its function contribute to host resilience or susceptibility to stress induced psychopathologies. The current study aimed to characterize differences in the gut microbial community structure and function that mediate vulnerability or resilience to traumatic stress in the Single Prolonged Stress (SPS) animal model of PTSD. Sprague‐Dawley male rats were divided into unstressed controls and SPS experimental group. After 14 days, behavioral analyses were performed using Open Field, Social Interaction and Elevated Plus Maze tests. Based on the anxiety measures, the SPS group was further subdivided into SPS‐resilient (R) and SPS‐susceptible (S) subgroups. After the last behavioral test, the animals were sacrificed and cecum, colon, hippocampus, and medial prefrontal cortex were collected. Prior to SPS and immediately after Open Field test, fecal samples were collected from each rat for 16S V3‐V4 ribosomal sequencing; whereas urine samples were collected before SPS, 90 minutes into immobilization and on the day of dissection to measure urinary epinephrine (epi) and norepinephrine (norepi) levels. Analyses of the fecal microbiota revealed significant differences among the groups before and after SPS stressors. Before SPS, the SPS‐S subgroup harbored microbiota with an overall pro‐inflammatory phenotype, such as significantly increased levels of Clostridia, and decreased levels of Lactobacillusand Barnesiella compared to the SPS‐R subgroup. After SPS, among the many changes observed were significant shifts in the abundance of Firmicutes and Bacteroidetes in SPS subgroups. Urinary epi and norepi levels were also different among the groups, with SPS‐S subgroup having higher baseline catecholamines levels. In line with the alterations seen in the gut microbiota, the levels of cecal short chain fatty acids were also altered, with SPS‐S subgroup having significantly lower levels of Acetate, Valerate and Caproate. Interestingly, the levels of acetate inversely correlated with anxiety index. The colon length and permeability were also altered, with SPS‐S having significantly shorter colon and increased permeability as measured by Claudin‐1 expression. Finally, analyses of different brain regions also revealed significant increases in blood brain barrier permeability in SPS‐S subgroup as determined by Claudin‐5 expression. Taken together, our results suggest microbiota is a potential factor in predisposing subjects either to stress susceptibility or resilience. Moreover, SPS triggered significant shifts in the gut microbiota, their metabolites and brain and gut permeability. These findings could lead to new therapeutic directions for PTSD possibly through the controlled manipulation of gut microbiota. It may enable early identification of individuals more likely to develop prolonged anxiolytic symptoms following traumatic stress.

Gut commensal Coprococcus comes diminishes the blood pressure‐lowering effect of ester angiotensin‐converting enzyme inhibitors

IntroductionDrug resistant HTN (rHTN) affects around 15% to 20% of hypertensive (HTN) patients. The underlying mechanisms of resistance to treatment remain poorly understood. The majority of angiotensin‐converting enzyme inhibitors (ACEi) are esters, whereby we hypothesized that select gut microbiota hydrolyze ACEi rendering lower efficacy (Figure 1A). To test this hypothesis, we investigated if and which gut microbe modulates the effectiveness of ACEi.MethodsVancomycin, Meropenem and Omeprazole (VMO) were given to 16‐week‐old male Spontaneously Hypertensive Rats (SHR) at 50 mg/kg/day for five days. A single dose of 8mg/kg Quinapril was orally administered to both SHR and SHR+VMO, and blood pressure (BP) was recorded via radio‐telemetry. Liquid chromatography–mass spectrometry was used to measure the catabolism of quinapril. The hydrolysis of p‐nitro‐phenylbutyrate was used to measure the activity of bacterial esterase. 16S rRNA sequencing was used to study the microbial composition. At last, ester ACEi ramipril and non‐ester lisinopril were co‐administered with Coprococcus comes, respectively, to generalize the effect of C. comes on ACEi's effectiveness.ResultsCompared to the SHR, depletion of gut microbiota in the SHR+VMO group preserved the BP lowering effect of Quinapril, an ester ACEi (Figure 1B). The SHR+VMO group showed (1) reduced Coprococcus (Figure 1C); (2) lower esterase activity per gram of cecal microbiota to hydrolyze quinapril (Figure 1D); (3) a 50% lower reduction in quinapril quantity (nmol) after incubation with 1mg of cecal lysate for 3 hr (Figure 1E). C. comes,a species in Coprococcusgenus, catabolized quinapril in vitro and reduced its BP‐lowering effects in the SHR (Figure 2A‐B). Importantly, C. comes also reduced the BP‐lowering effects of ramipril (ester), but not lisinopril (non‐ester) in the SHR (Figure 2C‐D).ConclusionThese observations constitute the first report of an unrecognized role of a select gut microbe, C. comes, in reducing the effectiveness of ester ACEi. As such, this mechanistic study serves as the foundation for expanding clinical management of antihypertensive drug resistance via manipulation of gut microbiota.

Microbiota regulation of development of thymic microbiota-specific T cells

Abstract While exposure to microbial antigens in peripheral sites causes expansion of antigen-specific T cells, a role for antigen-specific expansion had not been identified during T cell development in the thymus. We recently found that intestinal colonization induced intestinal dendritic cells migration to the thymus, driving thymic expansion of microbiota-specific T cells early in life. In contrast, colonization in adulthood leads to expansion of peripheral but not thymic microbiota-specific T cells. Thymic microbiota-specific T cells developed early in life were undifferentiated and caused intestinal inflammation in immunocompromised hosts upon antigen reencounter. We sought to understand regulation of this developmental window and define if thymic expansion of microbiota-specific T cells could be restarted in adult mice. We found that microbiota manipulation reestablished expansion of microbiota-specific T cells in the thymus of adult mice. We are in the process of characterizing these T cells in adulthood to assess their impact on intestinal inflammation. Our data suggests that intestinal colonization controls the generation of thymic microbiota-specific T cells which has the potential to modulate inflammatory processes.

Tumor-intrinsic factors dictate beneficial effect of microbiota-based therapies

Abstract Gut microbiota impacts antitumor immunity and recent studies have shown that manipulating microbiota via fecal transplant can rescue immune checkpoint blockade (ICB) response in refractory melanoma patients. However, not all patients benefited from this approach. We hypothesize that tumor-intrinsic factors (e.g. neoantigen load and immune microenvironment) contribute to the microbiota effect on anticancer response. To test this, we performed preclinical microbiota manipulation studies using dietary intervention. Mice fed high-fiber diet (FD) had improved spontaneous tumor control and response to ICB. Mechanistically, FD-induced changes in microbiota composition skewed the tumor innate immune repertoire towards an antitumor profile marked by increased dendritic cell infiltration. Downstream of the innate compartment, FD reduced the proportion of intratumoral Tregs and exhausted CD8+ T cells. We further assessed the effects of FD across 8 tumor models including EL4 lymphoma, MC38 colon carcinoma, and 6 melanomas (M1–M6) that mimic the variety of human melanoma subtypes. Although FD had a beneficial effect overall, not all models responded to the same extent, and were accompanied by different changes in the tumor immune profile. FD delayed tumor initiation for EL4 and M4, reduced growth rate for M3 and M5, both delayed initiation and reduced growth rate for MC38, M2, and M6, but had no significant effects for M1. Additionally, we found that increasing tumor immunogenicity resulted in a synergistic effect with FD. Our data suggests that tumor-intrinsic factors influence the beneficial effect of microbiota on antitumor immunity. Identifying these factors will help refine the use of microbiota-based therapies in the clinic. This research was supported by the Intramural Research Program of the NIH (CCR-NCI). This research was supported by the Intramural Research Program of the NIH (CCR-NCI).

Prebiotics and Postbiotics Synergistic Delivery Microcapsules from Microfluidics for Treating Colitis.

Manipulation of gut microbiota by bacterial metabolites has shown protective effects against colitis; while the efficacy is strictly limited by the poor oral delivery efficiency and single drug usage. Here, a novel prebiotics and postbiotics synergistic delivery microcapsule composed of indole‐3‐propionic acid (IPA) postbiotic and three prebiotics including alginate sodium, resistant starch (RS), and chitosan via microfluidic electrospray for preventing and treating colitis are proposed. It is found that oral administration of IPA microcapsules (IPA@MC) to mice can exert significant protective effects to colitis, suggesting the therapeutic synergy between prebiotics and postbiotics. Furthermore, the mechanism of the IPA@MC is revealed in modulating the gut microbiota, that is by significantly increasing the overall richness and abundance of short‐chain fatty acids (SCFA) producing bacteria such as Faecalibacterium and Roseburia. These results indicate that the prebiotics and postbiotics synergistic delivery microcapsules are ideal candidates for treating colitis.

A Pilot Study Exploring the Association of Entacapone, Gut Microbiota, and the Subsequent Side Effects in Patients With Parkinson's Disease.

Background and AimsEntacapone, one of the most common drugs distributed among patients with Parkinson’s disease, is a peripherally acting catechol-O-methyltransferase (COMT) inhibitor that is used in addition to levodopa to control symptoms. However, there have been negative effects reported against entacapone, namely, gastrointestinal (GI) problems and drowsiness. In this pilot study, we aim to examine the hypothesis that the discomfort induced by entacapone might be originated from the shift of microbial composition by adjusting the effect of levodopa.MethodsThe population in this pilot study consisted of 13 PD patients treated with levodopa only and 11 with both levodopa and entacapone. The 16S rRNA gene sequence data were processed, aligned, and categorized using the DADA2. Alpha diversity indices for Observed, Chao1, Shannon, and Simpson metrics were calculated with Phyloseq 1.32.0. Dissimilarities were calculated using unweighted unique fraction metrics (Unifrac), weighted Unifrac, and Canberra distance. Functional differences were calculated by PICRUSt2 based on the KEGG database.ResultsResults of 16S rRNA sequencing analysis showed that while entacapone did not influence the species richness, the composition of the microbial community shifted considerably. Relative abundances of bacteria related to constipation and other GI disorders also altered significantly. Functional enrichment analysis revealed changes in the metabolic activity of alanine, aspartate, and glutamate. These amino acids are related to common side effects of entacapone such as auditory hallucinations, fatigue, and nightmare.ConclusionOur findings provide testable hypothesis on the cause of unpleasant side effects of entacapone, which in the long run could possibly be reduced through gut microbiota manipulation.

Colonization of the live biotherapeutic product VE303 and modulation of the microbiota and metabolites in healthy volunteers

Manipulation of the gut microbiota via fecal microbiota transplantation (FMT) has shown clinical promise in diseases such as recurrent Clostridioides difficile infection (rCDI). However, the variable nature of this approach makes it challenging to describe the relationship between fecal strain colonization, corresponding microbiota changes, and clinical efficacy. Live biotherapeutic products (LBPs) consisting of defined consortia of clonal bacterial isolates have been proposed as an alternative therapeutic class because of their promising preclinical results and safety profile. We describe VE303, an LBP comprising 8 commensal Clostridia strains under development for rCDI, and its early clinical development in healthy volunteers (HVs). In a phase 1a/b study in HVs, VE303 is determined to be safe and well-tolerated at all doses tested. VE303 strains optimally colonize HVs if dosed over multiple days after vancomycin pretreatment. VE303 promotes the establishment of a microbiota community known to provide colonization resistance.

The role of microbiota in nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is the most frequent liver disease worldwide. Gut microbiota can play a role in the pathogenesis of NAFLD since dysbiosis is associated with reduced bacterial diversity, altered Firmicutes/Bacteroidetes ratio, a relative abundance of alcohol-producing bacteria, or other specific genera. Changes can promote disrupted intestinal barrier and hyperpermeability, filtration of bacterial products, activation of the immune system, and pro-inflammatory changes in the intestine, in the liver, and at a systemic level. Microbiota-derived molecules can contribute to the steatogenic effects. The link between gut dysbiosis and NAFLD, however, is confused by several factors which include age, BMI, comorbidities, dietary components, and lifestyle. The role of toxic chemicals in food and water requires further studies in both gut dysbiosis and NAFLD. We can anticipate that gut microbiota manipulation will represent a potential therapeutic tool to delay or reverse the progression of NAFLD, paving the way to primary prevention measures.

Microbiota transplantation in portal hypertension: promises and pitfalls.

In this commentary, we discuss new findings indicating that microbiota transplantation has favorable impact on portal hypertension (PH) in the experimental model of cirrhosis induced by bile duct ligation (BDL) (Huang et al.; Clin Sci (Lond) (2021) 135(24): 2709-2728, doi: 10.1042/CS20210602). Sinusoidal PH is an ominous outcome of advanced chronic liver disease, characterized by increased intrahepatic vascular resistance (IHVR), splanchnic hyperemia, and the development of portosystemic collaterals. In the work of Huang et al., microbiota transplantation not only alleviated splanchnic hyperdynamic circulation by improving vascular responsiveness and decreasing mesenteric angiogenesis, but also reduced blood flow in portosystemic collaterals. Surprisingly, however, microbiota transplantation had no effect on intrahepatic vasoconstriction in this experimental model. We discuss these observations in the context of recent literature showing that manipulation of the gut microbiota (either by transplantation or through the use of probiotics) may improve IHVR, which is one of the earliest abnormalities in the pathogenesis of sinusoidal PH. Further research is needed to explore the specific molecular and cellular targets associated with the correction of dysbiosis in liver disease.

Microbiota manipulation to prevent oxalate kidney stone formation.

Microbiota manipulation to prevent oxalate kidney stone formation.

Secreted Glycoside Hydrolase Proteins as Effectors and Invasion Patterns of Plant-Associated Fungi and Oomycetes.

During host colonization, plant-associated microbes, including fungi and oomycetes, deliver a collection of glycoside hydrolases (GHs) to their cell surfaces and surrounding extracellular environments. The number and type of GHs secreted by each organism is typically associated with their lifestyle or mode of nutrient acquisition. Secreted GHs of plant-associated fungi and oomycetes serve a number of different functions, with many of them acting as virulence factors (effectors) to promote microbial host colonization. Specific functions involve, for example, nutrient acquisition, the detoxification of antimicrobial compounds, the manipulation of plant microbiota, and the suppression or prevention of plant immune responses. In contrast, secreted GHs of plant-associated fungi and oomycetes can also activate the plant immune system, either by acting as microbe-associated molecular patterns (MAMPs), or through the release of damage-associated molecular patterns (DAMPs) as a consequence of their enzymatic activity. In this review, we highlight the critical roles that secreted GHs from plant-associated fungi and oomycetes play in plant–microbe interactions, provide an overview of existing knowledge gaps and summarize future directions.