Disruption of Genes Encoding Putative Zwitterionic Capsular Polysaccharides of Diverse Intestinal Bacteroides Reduces the Induction of Host Anti-Inflammatory Factors

Study on characteristics of gut flora composition of pregnant women with preeclampsia

OBJECTIVES

To explore the relationship between preeclampsia and the changes of the intestinal microflora.

METHODS

Illumina HiSeq sequencing platform was used to sequencing the 16S rRNA of bacteria in stool samples from 54 pregnant women. The experimental group included 27 women with preeclampsia (PRE), consisting of 13 women with severe preeclampsia (SP) and 14 women with non-severe preeclampsia (P). The control group comprised 27 healthy pregnant women (NOR).

RESULTS

The bacterial Alpha diversity of the PRE group was higher than that of the normal group, but P>0.05. The dominant flora in the four groups were Bacteroidetes, Firmicutes, and Proteobacteria. The abundance of Synergistetes in the PRE group was significantly lower than that in normal group and Bacteroidetes in the P group was significantly higher than that in SP group, and Firmicutes in the P group was significantly lower than that in the SP group(P < 0.05). LEfSe analyses showed, there were 9 flora differences between PRE group and NOR group, between P and SP groups that only Ruminococcaceae showed a difference. Differential species screening showed, there are 3 flora were significantly different between the PRE vs. NOR groups (P < 0.05). There are 4 flora were significantly different between the P vs. SP groups (P < 0.05). Functional difference analysis showed significant differences in 8 signaling pathways between the NOR group and the PRE group and 11 signaling pathways between P group and SP group.

CONCLUSION

There are significant changes in intestinal flora between preeclampsia patients and healthy controls, which may be involved in the regulation of the occurrence and development of preeclampsia.

The Role of the Gut Microbiota in Modulating Signaling Pathways and Oxidative Stress in Glioma Therapies

Tumors of the central nervous system (CNS), especially gliomas, pose a significant clinical challenge due to their aggressive nature and limited therapeutic options. Emerging research highlights the critical role of the gut microbiota in regulating CNS health and disease. The composition of the gut microbiota is essential for maintaining CNS homeostasis, as it modulates immune responses, oxidative status, and neuroinflammation. The microbiota-gut-brain axis, a bidirectional communication network, plays a pivotal role in cancer and CNS disease treatment, exerting its influence through neural, endocrine, immunological, and metabolic pathways. Recent studies suggest that the gut microbiota influences the solidification of the tumor microenvironment and that dysbiosis may promote glioma development by modulating systemic inflammation and oxidative stress, which contributes to tumorigenesis and CNS tumor progression. This review interrogates the impact of the gut microbiota on glioma, focusing on critical pathways such as NF-κB, MAPK, PI3K/Akt/mTOR, and Kynurenine/AhR that drive tumor proliferation, immune evasion, and therapy resistance. Furthermore, we explore emerging therapeutic strategies, including probiotics and microbiota-based interventions, which show potential in modulating these pathways and enhancing immunotherapies such as checkpoint inhibitors. By focusing on the multifaceted interactions between the gut microbiota, oxidative stress, and CNS tumors, this review highlights the potential of microbiota-targeted therapies and their manipulation to complement and enhance current treatments.

Integrative analysis of intestinal flora and untargeted metabolomics in attention-deficit/hyperactivity disorder

Attention Deficit Hyperactivity Disorder (ADHD) is a clinically common neurodevelopmental disorder of the brain. In addition to genetic factors, an imbalance in gut flora may also play a role in the development of ADHD. Currently, it is critical to investigate the function of gut flora and related metabolites, which may form the fundamental basis of bidirectional cross-linking between the brain and the gut, in addition to focusing on the changed gut flora in ADHD. This study aimed to investigate the possible relationship between changes in gut flora and metabolites and ADHD by analyzing metagenome and untargeted metabolomics of fecal samples from ADHD patients. Specifically, we attempted to identify key metabolites and the metabolic pathways they are involved in, as well as analyze in detail the structure and composition of the gut flora of ADHD patients. In order to further investigate the relationship between gut flora and ADHD symptoms, some behavioral studies were conducted following the transplantation of gut flora from ADHD patients into rats. The results of the metagenome analysis revealed several distinct strains, including Bacteroides cellulosilyticus, which could be important for diagnosing ADHD. Additionally, the ADHD group showed modifications in several metabolic pathways and metabolites, including the nicotinamide and nicotinic acid metabolic pathways and the metabolite nicotinamide in this pathway. The behavioral results demonstrated that rats with ADHD gut flora transplants displayed increased locomotor activity and interest, indicating that the onset of behaviors such as ADHD could be facilitated by the flora associated with ADHD. This research verified the alterations in gut flora and metabolism observed in ADHD patients and provided a list of metabolites and flora that were significantly altered in ADHD. Simultaneously, our findings revealed that modifications to the microbiome could potentially trigger behavioral changes in animals, providing an experimental basis for comprehending the function and influence of gut flora on ADHD. These results might provide new perspectives for the development of novel treatment strategies.

Characterization and Safety Evaluation of Autoclaved Gut Commensal Parabacteroides goldsteinii RV-01

Gut commensals play important roles in maintaining the homeostasis of human health. Previous studies indicated that the abundance of P. goldsteinii in animal hosts was increased by the administration of prebiotics such as polysaccharides purified from iconic oriental medicinal fungi. Subsequently, P. goldsteinii was found to exert beneficial effects on the amelioration of multiple chronic inflammation-associated diseases. Even so, during the process of the development of P. goldsteinii as a next-generation probiotic (NGP), care has to be taken when it is used as a functional food ingredient. In this study, we isolated a novel P. goldsteinii strain, RV-01, from the feces of a healthy adult and carried out comprehensive analyses of its genomic and phenotypic characteristics. Bioinformatic analysis of P. goldsteinii RV-01 revealed the absence of potential virulence genes, as well as the presence of genes and traits potentially beneficial to human health, such as the production of short-chain fatty acids, anti-inflammatory lipopolysaccharides, and zwitterionic capsular polysaccharides, as well as immune regulatory proteins. To circumvent any potential side effects, the P. goldsteinii RV-01 was autoclaved before proceeding to the nonclinical safety assessment. The autoclaved P. goldsteinii RV-01 retained its anti-inflammatory effect in human colon epithelial cells. In addition to the three genotoxicity assays, 28-day subacute and 90-day subchronic animal toxicity studies (the highest dose tested was equivalent to 8.109 × 1010P. goldsteinii RV-01 cells/kg body weight/day) were also implemented. The results of all studies were negative for toxicity. These results support the conclusion that autoclaved P. goldsteinii RV-01 is safe for use as a food ingredient.

Structural elucidation of a capsular polysaccharide from Bacteroides uniformis and its ameliorative impact on DSS-induced colitis in mice

Capsular polysaccharides derived from Bacteroides species have emerged as potential mitigators of intestinal inflammation in murine models. However, research on capsular polysaccharides from B. uniformis, a Bacteroides species with reduced abundance in colons of patients with ulcerative colitis, remains scarce. In this study, we extracted a neutral polysaccharide component from B. uniformis ATCC8492, termed BUCPS1B, using ultrasonic disruption, ethanol precipitation, and anion exchange chromatography. Structural characterization revealed BUCPS1B as a water-soluble polysaccharide with an α-1,4-glucan main chain adorned with minor substituent sugar residues. BUCPS1B alleviated intestinal inflammation in a mouse model of colitis and induced polarization of macrophages into M2-type. Furthermore, BUCPS1B modulated the gut microbiota composition, increased the abundance of the probiotic Akkermansia muciniphila and altered the gut metabolic profile to promote phenylalanine and short chain fatty acids metabolism. BUCPS1B is therefore a promising candidate to prevent inflammation and augment intestinal health.

Nontoxigenic Bacteroides fragilis: A double-edged sword

The contribution of commensal microbes to human health and disease is unknown. Bacteroides fragilis (B. fragilis) is an opportunistic pathogen and a common colonizer of the human gut. Nontoxigenic B. fragilis (NTBF) and enterotoxigenic B. fragilis (ETBF) are two kinds of B. fragilis. NTBF has been shown to affect the host immune system and interact with gut microbes and pathogenic microbes. Previous studies indicated that certain strains of B. fragilis have the potential to serve as probiotics, based on their observed relationship with the immune system. However, several recent studies have shown detrimental effects on the host when beneficial gut bacteria are found in the digestive system or elsewhere. In some pathological conditions, NTBF may have adverse reactions. This paper presents a comprehensive analysis of NTBF ecology from the host-microbe perspective, encompassing molecular disease mechanisms analysis, bacteria-bacteria interaction, bacteria-host interaction, and the intricate ecological context of the gut. Our review provides much-needed insights into the precise application of NTBF.

The role of the glycome in symbiotic host-microbe interactions

Glycosylation plays a crucial role in many aspects of cell biology, including cellular and organismal integrity, structure-and-function of many glycosylated molecules in the cell, signal transduction, development, cancer, and in a number of diseases. Besides, at the inter-organismal level of interaction, a variety of glycosylated molecules are involved in the host-microbiota recognition and initiation of downstream signalling cascades depending on the outcomes of the glycome-mediated ascertainment. The role of glycosylation in host-microbe interactions is better elaborated within the context of virulence and pathogenicity in bacterial infection processes but the symbiotic host-microbe relationships also involve substantive glycome-mediated interactions. The works in the latter field have been reviewed to a much lesser extent, and the main aim of this mini-review is to compensate for this deficiency and summarise the role of glycomics in host-microbe symbiotic interactions.

Advances in synthetic biology toolboxes paving the way for mechanistic understanding and strain engineering of gut commensal Bacteroides spp. and Clostridium spp

The gut microbiota plays a significant role in influencing human immunity, metabolism, development, and behavior by producing a wide range of metabolites. While there is accumulating data on several microbiota-derived small molecules that contribute to host health and disease, our knowledge regarding the molecular mechanisms underlying metabolite-mediated microbe-host interactions remains limited. This is primarily due to the lack of efficient genetic tools for most commensal bacteria, especially those belonging to the dominant phyla Bacteroides spp. and Clostridium spp., which hinders the application of synthetic biology to these gut commensal bacteria. In this review, we provide an overview of recent advances in synthetic biology tools developed for the two dominant genera, as well as their applications in deciphering the mechanisms of microbe-host interactions mediated by microbiota-derived small molecules. We also discuss the potential biomedical applications of engineering commensal bacteria using these toolboxes. Finally, we share our perspective on the future development of synthetic biology tools for a better understanding of small molecule-mediated microbe-host interactions and their engineering for biomedical purposes.