Project description:Humans and their microbiota have coevolved a mutually beneficial relationship, with the human host providing a hospitable environment for the microbes, and the microbiota providing many benefits including nutritional benefits and protection from pathogen infection1. Maintaining this relationship requires careful immune balance to contain commensals within the lumen while limiting inflammatory anti-commensal responses1,2. A number of groups describe T cell antigen-specific recognition of intestinal microbes3,4. While the local environment shapes effector cell differentiation3–5 it is unclear how microbiota-specific T cells are educated in the thymus. Here we identify that early life intestinal colonization leads to trafficking of microbial antigens from the intestine to the thymus by intestinal dendritic cells (DCs) which then expand microbiota-specific T cells. Once in the periphery, microbiota-specific T cells have pathogenic potential, or can protect against related pathogens. In this way, the developing microbiota shapes and expands the thymic and peripheral T cell repertoire, allowing for enhanced recognition of intestinal microbes and pathogens.
Project description:Major depressive disorder is caused by gene-environment interactions and the gut microbiota plays a pivotal role in the development of depression. However, the mechanisms by which the gut microbiota modulates depression remain elusive. Herein, we detected the differentially expressed hippocampal long non-coding RNAs (lncRNAs), messenger RNAs (mRNAs) and microRNAs (miRNAs) between mice inoculated with gut microbiota from major depressive disorder patients or healthy controls, to identify the effects of gut microbiota-dysbiosis on gene regulation patterns at the transcriptome level. We also performed functional analysis to explore the microbial-regulated pathological mechanisms of depression. Two hundred mRNAs, 358 lncRNAs and 4 miRNAs were differentially expressed between the two groups. Functional analysis of these differentially expressed mRNAs indicated dysregulated inflammatory response to be the primary pathological change. Intersecting the differentially expressed mRNAs with targets of differentially expressed miRNAs identified 47 intersected mRNAs, which were mainly related to neurodevelopment. Additionally, we constructed a microbial-regulated lncRNA-miRNA-mRNA network based on RNA-RNA interactions. According to the competitive endogenous RNA hypothesis, two neurodevelopmental ceRNA sub-networks implicating in depression were identified. This study provides new understanding of the pathogenesis of depression induced by gut microbiota-dysbiosis and may act as a theoretical basis for the development of gut microbiota-based antidepressants.
Project description:Clostridioides difficile is one of the most common nosocomial pathogens and a global public health threat. Upon colonization of the gastrointestinal tract, C. difficile is exposed to a rapidly changing polymicrobial environment and a dynamic metabolic milieu. Despite the link between the gut microbiota and susceptibility to C. difficile, the impact of synergistic interactions between the microbiota and pathogens on the outcome of infection is largely unknown. Here, we show that microbial cooperation between C. difficile and Enterococcus has a profound impact on the growth, metabolism, and pathogenesis of C. difficile.. Through a process of nutrient restriction and metabolite cross-feeding, E. faecalis shapes the metabolic environment in the gut to enhance C. difficile fitness and increase toxin production. These findings demonstrate that members of the microbiota, such as Enterococcus, have a previously unappreciated impact on C. difficile behavior and virulence.
Project description:The gut microbiota and tumor-associated macrophages (TAM) impact anti-PD-1 checkpoint blockade. Reprogramming TAM by either blocking or deleting the macrophage receptor TREM2 attenuates tumor growth, and lack of functional TREM2 enhances tumor elimination by anti-PD-1. Here, we found that anti-PD-1 combined with TREM2 deficiency induces proinflammatory programs in intestinal macrophages and a concomitant expansion of Ruminococcus gnavus (R. gnavus) in the gut microbiota. Gavage of wild-type mice with R. gnavus recapitulated enhancement of anti-PD-1-mediated tumor elimination occurring in the absence of TREM2. The intestinal proinflammatory environment coincided with expansion, increased circulation and migration of TNF-producing CD4+ T cells to the tumor bed. Thus, TREM2 remotely controls anti-PD-1 checkpoint blockade through modulation of the intestinal immune environment and microbiota, with R. gnavus emerging as a potential probiotic agent for increasing responsiveness to anti-PD-1.
Project description:Insect gut microbiota plays important roles in acquiring nutrition, preventing pathogens infection, immune responses, and communicating with the environment. Gut microbiota can be affected by some external factors such as foods, temperature, and antibiotics. Spodoptera frugiperda (Lepidoptera: Noctuidae) is an important destructive pest of grain crops all over the world. The function of gut microbiota in S. frugiperda remains to be investigated. In this study, we fed the S. frugiperda with the antibiotic mixture (penicillin, gentamicin, rifampicin, and streptomycin) to perturb the gut microbiota, and further examined the effect of dysbiosis in gut microbiota on the gene expression of S. frugiperda by RNA sequencing. We found the composition and diversity of the gut bacterial community were changed in S. frugiperda after antibiotics treatmen, and the expression of genes related to energy and metabolic process were affected after antibiotics exposure in S. frugiperda. Our work will help understand the role of gut microbiota in insects.
Project description:Thyroid cancer (TC), the most common malignancy of the endocrine system, is currently the fifth most common malignancy diagnosed in women (1). The incidence of TC in the United States has increased by an average of 3% per year over the past 4 decades. Much progress has been made in exploring the etiology and pathogenesis of thyroid cancer, while the exact etiology remains unknown, TC is thought to arise from interactions between genetic susceptibility factors, epigenetic effects, and various environmental factors. Besides the improvement of diagnosis, TC increasing incidence emphasize that other important factors such as the environment play an important role in disease pathogenesis. While microbiota as an environment factor to some cancers accept widespread attention, if microbiota also as a risk factor for TC, it is worthy to be considered.
Project description:We found that mainstream cigarette smoking (4 cigarettes/day, 5 days/week for 2 weeks using Kentucky Research Cigarettes 3R4F) resulted in >20% decrease in the percentage of normal Paneth cell population in Atg16l1 T300A mice but showed minimal effect in wildtype littermate control mice, indicating that Atg16l1 T300A polymorphism confers sensitivity to cigarette smoking-induced Paneth cell damage. We performed cohousing experiments to test if Paneth cell phenotype is horizontally transmissible as is microbiota. Atg16l1 T300A and littermate controls that were exposed to cigarette smoking were used as microbiota donors, and these donor mice were exposed to smoking for 2 weeks prior to cohousing. Separate groups of Atg16l1 T300A and littermate controls that were not exposed to cigarette smoking were used as microbiota recipients. The microbiota recipients were co-housed with microbiota donors of the same genotype for 4 weeks, during this period the donors continued to be exposed to cigarette smoking. Cigarette smoking was performed using smoking chamber with the dosage and schedule as described above. At the end of the experiment, the fecal microbiota composition was analyzed by 16S rRNA sequencing.
Project description:Neural control of visceral organ function is essential for homeostasis and health. Intestinal peristalsis is critical for digestive physiology and host defence and is often dysregulated in gastrointestinal (GI) disorders. Luminal factors, such as diet and microbiota regulate neurogenic programs of gut motility, but the underlying molecular mechanisms remain unclear. Here we show that the transcription factor Aryl hydrocarbon Receptor (AhR) functions as a biosensor in intestinal neural circuits linking their functional output to the microbial environment of the gut lumen. Using nuclear RNA sequencing of mouse enteric neurons representing distinct intestinal segments and microbiota states, we demonstrate that the intrinsic neural networks of the colon exhibit unique transcriptional profiles controlled by the combined effects of host genetic programmes and microbial colonisation. Microbiota-induced expression of AhR in neurons of the distal gastrointestinal tract enables them to respond to the luminal environment and induce expression of neuron-specific effector mechanisms. Neuron-specific deletion of Ahr or constitutive overexpression of its negative feedback regulator CYP1A1, results in reduced peristaltic activity of the colon, similar to that observed in microbiota-depleted mice. Finally, expression of Ahr in enteric neurons of antibiotic-treated mice partially restores intestinal motility. Taken together, our experiments identify AhR signalling in enteric neurons as a regulatory node that integrates the luminal environment with the physiological output of intestinal neural circuits towards gut homeostasis and health. The enteric nervous system (ENS) encompasses the intrinsic neural networks of the gastrointestinal (GI) tract, which regulate most aspects of intestinal physiology, including peristalsis. In addition to host-specific genetic programmes, microbiota and diet have emerged as critical regulators of gut tissue physiology and changes in the microbial composition of the lumen often accompany GI disorders. We found that gut environmental sensor Aryl hydrocarbon receptor (AhR) is induced in colonic neurons in response to microbiota colonisation and regulates intestinal peristalsis in an AhR ligand-dependent manner. In this experiment, we used RNA sequencing to identify genes regulated in mouse colonic neurons by AhR activation.
Project description:Chronic inflammation and gut microbiota dysbiosis are risk factors for colorectal cancer. In clinical practice, inflammatory bowel disease (IBD) patients have a greatly increased risk of developing colitis associated colorectal cancer (CAC). However, the basis underlying the initiation of CAC remains to be explored. Systematic filtration through existing genome-wide association study (GWAS) and conditional deletion of Zfp90 in CAC mice model indicated that Zfp90 was a putative oncogene in CAC development. Strikingly, depletion of gut microbiota eliminated the tumorigenic effect of Zfp90 in CAC mice model. Moreover, fecal microbiota transplantation demonstrated Zfp90 promoted CAC depending on gut microbiota. Combining 16s rDNA sequencing in feces specimens from CAC mice model, we speculated that Prevotella copri-defined microbiota might mediate the oncogenic role of Zfp90 in the development of CAC. Mechanistic studies revealed Zfp90 accelerated CAC development through Tlr4-Pi3k-Akt-Nf-κb pathway. Our findings elucidated the crucial role of Zfp90-microbiota-Nf-κb axis in creating a tumor-promoting environment and suggested therapeutic targets for CAC prevention and treatment.