Deletion of both Dectin-1 and Dectin-2 affects the bacterial but not fungal gut microbiota and susceptibility to colitis in mice

Abelmoschi Corolla polysaccharides and related metabolite ameliorates colitis via modulating gut microbiota and regulating the FXR/STAT3 signaling pathway

Ulcerative Colitis (UC) is a chronic inflammatory disease of the intestinal tract with unknown definitive etiology. Polysaccharides are among the most important active components of Abelmoschi Corolla, exhibitings various pharmacological activities such as antioxidation and immunomodulation. However, no studies have yet reported the application of Abelmoschi Corolla Polysaccharides (ACP) in treating UC. This study aims to highlight the therapeutic efficacy of ACP in UC and reveal the underlying mechanism. The potential therapeutic effect is initially verified using a dextran sodium sulfate (DSS)-induced colitis model. 16S rRNA sequencing is performed using feces samples and untargeted metabolomics using serum samples to further reveal that ACP reprograms the dysbiosis triggered by UC progression, increases the abundance of Bacteroides spp., Blautia spp., and Parabacteroides spp. at the genus level and enriches the serum concentration of 7-ketodeoxycholic acid (7-KDA). Furthermore, using the FXR-/- mouse model, it is revealed that Farnesoid X Receptor (FXR) is a key target for ACP and the metabolite 7-KDA to block STAT3 phosphorylation by repairing the intestinal barrier to attenuate UC. Taken together, this work highlights the therapeutic potential of ACP against UC, mainly exerting its effects via modulating gut microbiota and regulating the FXR/STAT3 signaling pathway.

From sugar binders to diabetes fighters: the lectin saga of antihyperglycemic activity through systematic review and meta-analysis

Introduction

Lectins are carbohydrate-binding proteins that are extremely selective for sugar groups in the other molecules. As a result, they perform a variety of roles in biological processes involving cell, carbohydrate, and protein recognition at the cellular and molecular levels. Because lectins can bind to carbohydrates, they may play a role in determining the rate of carbohydrate digestion. They also bind to some proteins involved in diabetes mellitus (DM) pathophysiology. The present review aims to summarize the efficiency of lectins from different sources as potential antihyperglycemic agents.

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were employed for the drafting. In this regard, published scientific articles on the effects of different lectins on blood glucose (BG), glucose tolerance, hormonal effects, carbohydrate-digesting enzymes, oxidative stress, and insulin production process were collected from reputed journals using electronic databases. Furthermore, the toxicity effects of lectins from different sources were collected. A specific keyword search was completed to collect numerous articles with unique experimental designs and significant results. This was followed by the selection of the requisite articles based on the criteria designed by the authors. Data extraction was based on the common research elements included in the articles.

Results and Discussion

Of 13 identified studies, 11 studies were considered after double screening based on the inclusion criteria. All 11 pharmacological investigations were considered for review. Subsequent studies reflected on the pharmacological properties of lectins on the levels of BG, oxidative stress, β-cell proliferation, insulin resistance, inhibition of carbohydrate digesting enzymes, body weight, food and water intake, lipid profile, and other parameters. This review highlights lectins as potential anti-diabetic agents.

Conclusion

However, due to limited research, systematic evaluation is recommended for their development and promotion as effective potential antihyperglycemic agents. The clinical efficacy and safety of lectins against diabetes mellitus must also be evaluated.

Insights into gut fungi in pigs: A comprehensive review

Fungi in the gut microbiota of mammals play a crucial role in host physiological regulation, including intestinal homeostasis and host immune regulation. However, our understanding of gut fungi in mammals remains limited, especially in economically valuable animals, such as pigs. Therefore, this review first describes the classification and characterisation of fungi, provides insights into the methods used to study gut fungi, and summarises the recent progress on pig gut fungi. Additionally, it discusses the challenges in the study of pig gut fungi and highlights potential perspectives. The aim of this review is to serve as a valuable reference for advancing our knowledge of gut fungi in animals.

Integration of Gut Mycobiota and Oxidative Stress to Decipher the Roles of C-Type Lectin Receptors in Inflammatory Bowel Diseases

BACKGROUND

Ulcerative colitis (UC) and Crohn's disease (CD) are two subtypes of inflammatory bowel disease (IBD) with rapidly increased incidence worldwide. Although multiple factors contribute to the occurrence and progression of IBD, the role of intestinal fungal species (gut mycobiota) in regulating the severity of these conditions has been increasingly recognized. C-type lectin receptors (CLRs) on hematopoietic cells, including Dectin-1, Dectin-2, Dectin-3, Mincle and DC-SIGN, are a group of pattern recognition receptors (PRRs) that primarily recognize fungi and mediate defense responses, such as oxidative stress. Recent studies have demonstrated the indispensable role of CLRs in protecting the colon from intestinal inflammation and mucosal damage.

METHODS AND RESULTS

This review provides a comprehensive overview of the role of CLRs in the pathogenesis of IBD. Given the significant impact of mycobiota and oxidative stress in IBD, this review also discusses recent advancements in understanding how these factors exacerbate or ameliorate IBD. Furthermore, the latest developments in CLR-guided IBD therapy are examined to highlight the modulation of CLRs in fungal recognition and oxidative burst during the IBD process.

CONCLUSION

This review emphasizes the importance of CLRs in IBD, offering new perspectives on the etiology and therapeutic approaches for this disease.

Unveiling the Links Between Microbial Alteration and Host Gene Disarray in Crohn's Disease via TAHMC

A compelling correlation method linking microbial communities and host gene expression in tissues is currently absent. A novel pipeline is proposed, dubbed Transcriptome Analysis of Host-Microbiome Crosstalk (TAHMC), designed to concurrently restore both host gene expression and microbial quantification from bulk RNA-seq data. Employing this approach, it discerned associations between the tissue microbiome and host immunity in the context of Crohn's disease (CD). Further, machine learning is utilized to separately construct networks of associations among host mRNA, long non-coding RNA, and tissue microbes. Unique host genes and tissue microbes are extracted from these networks for potential utility in CD diagnosis. Experimental validation of the predicted host gene regulation by microbes from the association network is achieved through the co-culturing of Faecalibacterium prausnitzii with Caco-2 cells. Collectively, the TAHMC pipeline accurately recovers both host gene expression and microbial quantification from CD RNA-seq data, thereby illuminating potential causal links between shifts in microbial composition as well as diversity within CD mucosal tissues and aberrant host gene expression.

Genetically proxied intestinal microbiota and risk of erectile dysfunction

BACKGROUND

The interaction between intestinal microbiota and erectile dysfunction (ED) is less investigated. This study was performed to explore the association between intestinal microbiota and ED.

METHODS

In this two-sample Mendelian randomization (MR) study, genetic variants of gut microbiota were obtained from MiBioGen consortium containing 18,340 individuals. Six methods including inverse variance weighting (IVW), MR-Egger, weighted median, maximum likelihood, MR robust adjusted profile score, and MR pleiotropy residual sum and outlier were used to investigate the causal links between intestinal microbiota and ED. Furthermore, reverse MR analysis was performed to exclude the causal impact of ED on gut microbiota.

RESULTS

As revealed by the IVW estimator, the risks of ED were raised by genetically proxied Lachnospiraceae (OR: 1.27), Lachnospiraceae NC2004 group (OR: 1.17), Oscillibacter (OR: 1.20), Senegalimassilia (OR: 1.32) (All P < 0.05) and Tyzzerella-3 (OR: 1.14, P < 0.05). It was observed that Ruminococcaceae UCG013 exerted protective effect against ED (OR: 0.77, P < 0.05). These results were consistent with other estimators in sensitivity analyses. In reverse MR analyses, genetic liability to ED did not alter the abundances of Lachnospiraceae, Lachnospiraceae NC2004 group, Oscillibacter, Senegalimassilia, Tyzzerella-3, and Ruminococcaceae UCG013 (All P > 0.05). No heterogeneity and pleiotropy were detected by Cochran's Q-test, MR-Egger, and global test (All P > 0.05).

CONCLUSIONS

This study provided novel evidence that genetically proxied Lachnospiraceae, Lachnospiraceae NC2004 group, Oscillibacter, Senegalimassilia, Tyzzerella-3, and Ruminococcaceae UCG013 had potentially causal effects on ED. Further studies are needed to clarify the biological mechanisms linking intestinal microbiota to ED.

Polymorphisms in CLEC5A and CLEC7A genes modify risk for inflammatory bowel disease

Background

Inflammatory bowel disease (IBD) seems to arise from an interplay between genetic and environmental factors. CLEC5A and CLEC7A genes code for 2 members of the C-type lectin receptor superfamily, which participate in the immune response against various pathogens, mediating inflammatory signaling. CLEC5A polymorphisms have been linked to the risk of Crohn's disease (CD), whereas CLEC7A has been implicated in fungal dysbiosis, chemically induced colitis in mice and undertreated ulcerative colitis (UC) in humans. This study aimed to explore how specific CLEC5A and CLEC7A polymorphisms contribute to the development of CD and UC.

Methods

One hundred twelve CD patients, 94 UC patients and 164 sex- and age- matched healthy individuals were genotyped for the single nucleotide polymorphisms rs2078178 and rs16910631 of the CLEC7A gene, and rs1285933 of the CLEC5A gene.

Results

The CLEC7A rs2078178 AA genotype was more frequent in UC patients compared to healthy individuals, The CLEC7A rs16910631 CT genotype was significantly associated with UC risk compared to healthy individuals, while there was no statistical correlation with CD. The CLEC5A rs1285933 GA genotype was found to be protective against UC and CD, and the AA genotype against CD. Carriers of the rs1285933 A allele appeared to have reduced susceptibility to CD, implying that the presence of the A allele could be protective against CD development.

Conclusions

This is the first study to correlate the CLEC5A rs1285933 polymorphism with the risk for UC. The rs2078178 AA genotype and the CLEC7A rs16910631 CT could be promising biomarkers for UC susceptibility.

FMT rescues mice from DSS-induced colitis in a STING-dependent manner

Fecal microbiota transplantation (FMT) is currently a promising therapy for inflammatory bowel disease (IBD). However, clinical studies have shown that there is an obvious individual difference in the efficacy of FMT. Therefore, it is a pressing issue to identify the factors that influence the efficacy of FMT and find ways to screen the most suitable patients for this therapy. In this work, we targeted the stimulator of interferon genes (STING), a DNA-sensing protein that regulates host-defense. By comparing the differential efficacy of FMT in mice with different expression level of STING, it is revealed that FMT therapy provides treatment for DSS-induced colitis in a STING-dependent manner. Mechanistically, FMT exerts a regulatory effect on the differentiation of intestinal Th17 cells and macrophages, splenic Th1 and Th2 cells, as well as Th1 cells of the mesenteric lymph nodes via STING, down-regulating the colonic M1/M2 and splenic Th1/Th2 cell ratios, thereby improving the imbalanced immune homeostasis in the inflamed intestine. Meanwhile, based on the 16SrDNA sequencing of mice fecal samples, STING was found to facilitate the donor strain colonization in recipients' gut, mainly Lactobacillales, thereby reshaping the gut microbiota disturbed by colitis. Consequently, we proposed that STING, as a key target of FMT therapy, is potentially a biomarker for screening the most suitable individuals for FMT to optimize treatment regimens and enhance clinical benefit.

Microbial sensing in the intestine

The gut microbiota plays a key role in host health and disease, particularly through their interactions with the immune system. Intestinal homeostasis is dependent on the symbiotic relationships between the host and the diverse gut microbiota, which is influenced by the highly co-evolved immune-microbiota interactions. The first step of the interaction between the host and the gut microbiota is the sensing of the gut microbes by the host immune system. In this review, we describe the cells of the host immune system and the proteins that sense the components and metabolites of the gut microbes. We further highlight the essential roles of pattern recognition receptors (PRRs), the G protein-coupled receptors (GPCRs), aryl hydrocarbon receptor (AHR) and the nuclear receptors expressed in the intestinal epithelial cells (IECs) and the intestine-resident immune cells. We also discuss the mechanisms by which the disruption of microbial sensing because of genetic or environmental factors causes human diseases such as the inflammatory bowel disease (IBD).

Saccharomyces boulardii CNCM I-745 supplementation during and after antibiotic treatment positively influences the bacterial gut microbiota

Introduction

Antibiotic effects on gut bacteria have been widely studied, but very little is known about the consequences of such treatments on the mycobiota, the fungal part of the microbiota and how the length of administration influences both microbiota. Here, we examined the effect of antibiotics (ATB) on the composition of bacterial and fungal microbiota and how the administration of Saccharomyces boulardii CNCM I-745 influences both microbiota.

Methods

In order to get closer to the human microbiota, the mice used in this study were subjected to fecal microbiota transfer (FMT) using human feces and subsequently called human microbiotaassociated (HMA) mice. These mice were then treated with amoxicillinclavulanate antibiotics and supplemented with S. boulardii during and after ATB treatment to understand the effect of the yeast probiotic on both bacterial and fungal microbiota. Bacterial and fungal microbiota analyses were done using 16S and ITS2 rRNA amplicon-based sequencing.

Results

We showed that the administration of S. boulardii during ATB treatment had very limited effect on the fungal populations on the long term, once the yeast probiotic has been cleared from the gut. Concerning bacterial microbiota, S. boulardii administration allowed a better recovery of bacterial populations after the end of the ATB treatment period. Additionally, 16S and ITS2 rRNA sequence analysis revealed that 7 additional days of S. boulardii administration (17 days in total) enhanced the return of the initial bacterial equilibrium.

Discussion

In this study, we provide a comprehensive analysis of how probiotic yeast administration can influence the fungal and bacterial microbiota in a model of broad-spectrum antibiotherapy.

Immune functions of pattern recognition receptors in Lepidoptera

Pattern recognition receptors (PRRs), as the "sensors" in the immune response, play a prominent role in recognizing pathogen-associated molecular patterns (PAMPs) and initiating an effective defense response to pathogens in Lepidoptera. It is becoming increasingly clear that damage-associated molecular patterns (DAMPs) normally play a physiological role within cells; however, when exposed to extracellular, they may become "part-time" critical signals of the immune response. Based on research in recent years, we review herein typical PRRs of Lepidoptera, including peptidoglycan recognition protein (PGRP), gram-negative binding protein (GNBP), β-1,3-glucan recognition protein (βGRP), C-type lectin (CTL), and scavenger receptor (SR). We also outline the ways in which DAMPs participate in the immune response and the correlation between PRRs and immune escape. Taken together, these findings suggest that the role of PRRs in insect innate immunity may be much greater than expected and that it is possible to recognize a broader range of signaling molecules.

Prophylactic effect of Tongxieyaofang polysaccharide on depressive behavior in adolescent male mice with chronic unpredictable stress through the microbiome-gut-brain axis

Major depression disorder is more common among adolescents and is a primary reason for suicide in adolescents. Some antidepressants are ineffective and may possess side effects. Therefore, developing an adolescent antidepressant is the need of the hour. We designed the stress model of adolescent male mice induced by chronic unpredictable stress (CUS). The mice were treated using Tongxieyaofang neutral polysaccharide (TXYF-NP), Tongxieyaofang acidic polysaccharide (TXYF-AP), TXYF-AP + TXYF-NP and fructooligosaccharide + galactooligosaccharides to determine their body weight, behavior, and serum hormone levels. RT-qPCR was used to detect the gene expression of Crhr1, Nr3c1, and Nr3c2 in the hypothalamus and hippocampus and the gene expression of glutamic acid and γ-aminobutyric acid-related receptors in the hippocampus. RT-qPCR, Western blot, and ELISA detected tryptophan metabolism in the colon, serum, and hippocampus. 16s rDNA helped sequence colon microflora, and non-targeted metabolomics enabled the collection of metabolic profiles of colon microflora. In adolescent male mice, CUS induced depression-like behavior, hypothalamic-pituitary-adrenal axis hyperactivity, hippocampal tissue damage, abnormal expression of its related receptors, and dysregulation of tryptophan metabolism. The 16s rDNA and non-targeted metabolomics revealed that CUS led to colon microflora disorder and bile acid metabolism abnormality. Tongxieyaofang polysaccharide could improve the bacterial community and bile acid metabolism disorder by upregulating the relative abundance of Lactobacillus gasseri, Lachnospiraceae bacterium 28-4, Bacteroides and Ruminococcaceae UCG-014 while preventing CUS-induced changes. TXYF-P can inhibit depression-like behavior due to CUS by regulating colonic microflora and restoring bile acid metabolism disorder. Thus, based on the different comparisons, TXYF-NP possessed the best effect.

Genetic and Epigenetic Etiology of Inflammatory Bowel Disease: An Update

Inflammatory bowel disease (IBD) is a chronic disease with periods of exacerbation and remission of the disease. The etiology of IBD is not fully understood. Many studies point to the presence of genetic, immunological, environmental, and microbiological factors and the interactions between them in the occurrence of IBD. The review looks at genetic factors in the context of both IBD predisposition and pharmacogenetics.

Integrated multi-omics reveals novel microbe-host lipid metabolism and immune interactions in the donkey hindgut

Evidence has shown that gut microbiota play a key role in host metabolism and health; however, little is known about the microbial community in the donkey hindgut as well as the interactions that occur between gut microbes and the host. This study aimed to explore the gut microbiome differences by analyzing the microbial community and differentially expressed genes (DEGs) related to lipid metabolism and the immune system along the donkey hindgut. The hindgut tissues (cecum, ventral colon, and dorsal colon) were separated, and the contents of each section were collected from six male donkeys for multi-omics analysis. There were significant differences in terms of dominant bacteria among the three sections, especially between the cecum and dorsal colon sites. For instance, species belonging to Prevotella and Treponema were most abundant in the cecum, while the Clostridiales_bacterium, Streptococcus_equinus, Ruminococcaceae_bacterium, etc., were more abundant in the dorsal colon. Apart from propionate, the concentrations of acetate, isobutyrate, valerate and isovalerate were all lower in the cecum than in the dorsal colon (p < 0.05). Furthermore, we identified some interesting DEGs related to lipid metabolism (e.g., ME1, MBOAT1, ACOX1, ACOX2 and LIPH) and the immune system (e.g., MUC3B, mucin-2-like, IL17RC, IL1R2, IL33, C1QA, and MMP9) between the cecum and dorsal colon and found that the PPAR pathway was mainly enriched in the cecum. Finally, we found a complex relationship between the gut microbiome and gene expression, especially with respect to the immune system, and combined with protein-protein interaction (PPI) data, suggesting that the PPAR pathway might be responsible, at least in part, for the role of the hindgut microbiota in the donkeys' gut homeostasis. Our data provide an in-depth understanding of the interaction between the microbiota and function in the healthy equine hindgut and may also provide guidance for improving animal performance metrics (such as product quality) and equine welfare.