Project description:Colonizing commensal bacteria after birth are required for the proper development of the gastrointestinal tract. It is believed that bacterial colonization pattern in neonatal gut affects gut barrier function and immune system maturation. Studies on the development of faecal flora microbiota in infants on various formula feeds showed that the neonatal gut was first colonized with enterococci followed by other flora microbiota such as Bifidobacterium in breast feeding infants. Intriguingly, Bjorksten group Other studies showed that Bbabies who developed allergy were less often colonized with Enterococcus during the first month of life as compared to healthy infants. A lot of Many studies have been done on conducted to elucidate how bifidobacteria or lactobacilli, some of which are considered probiotic, regulate infant gut immunity. However, much fewer studies have been focused on enterococi. In our study, we demonstrate that E. faecalis, isolated from healthy newborns, suppress inflammatory responses activated in vivo and in vitro. We found E. faecalis attenuates proinflammatory cytokine secretions, especially IL-8, through JNK and p38 signaling pathways. This finding shed light on how the first colonizer, E.faecalis, regulate inflammatory responses in the host. Samples are analysed using web-based GEArray Expression Analysis Suite
Project description:At birth, newborns are exposed to gut microbiota, which plays a critical role in host physiology. A reduced level of microbial diversity has been associated with necrotizing enterocolitis (NEC), one of the most deadly diseases in premature infants, but the underlying disease mechanisms are still poorly understood. Although the epithelial turnover of germ free mice is significantly delayed compared to conventionally raised mice, it remains unclear how gut microbiota exposure in the early postnatal period promotes stem cell renewal and differentiation. By analyzing genetic and experimental mouse models and performing single cell analysis, we demonstrate that gut microbiota promotes stem cell differentiation through the activation of critical stromal niche components. Our single cell analysis reveals that gut microbiota controls the size and heterogeneity of macrophage populations that secrete Wnt ligands, thereby maintaining the proliferation of intestinal telocytes, a recently identified gut mesenchymal stem cell niche. We show that stem cell differentiation, when impaired by antibiotic treatment promotes NEC, while treatment with Lactobacillus, which in NEC is dramatically less abundant, rescues NEC-like pathology through the activation of macrophage and telocyte niches. Our work highlights the mechanisms of how gut microbiota-facilitate mesenchymal niche proliferation which supports stem cell differentiation in early postnatal development.
2022-12-16 | GSE163179 | GEO
Project description:Delivery mode impacts gut bacteriophage colonization during infancy
Project description:The gut microbiota plays an important role in host health. Microbiota dysbiosis has been implicated in the global epidemic of Metabolic Syndrome (MetS) and could impair host metabolism by noxious metabolites. It has been well established that the gut microbiota is shaped by host immune factors. However, the effect of T cells on the gut microbiota is yet unknown. Here, we performed a metagenomic whole-genome shotgun sequencing (mWGS) study of the microbiota of TCRb-/- mice, which lack alpha/beta T cells.
Project description:Inappropriate cross talk between mammals and their gut microbiota may trigger intestinal inflammation and drive extra-intestinal immune-mediated diseases. Studies with germ-free or gnotobiotic animals represent the gold standard for research on bacterial-host interaction but they are not readily accessible to the wide scientific community. We aimed at refining a protocol that in a robust manner would deplete murine intestinal microbiota and prove to have significant biologic validity. Previously published protocols for depleting mice of their intestinal microbiota by administering broad-spectrum antibiotics in drinking water were difficult to reproduce. We show that twice daily delivery of antibiotics by gavage depleted mice of their cultivable fecal microbiota and reduced the fecal bacterial DNA load by approximately 400 fold while ensuring the animals’ health. Mice subjected to the protocol for 17 days displayed enlarged ceca, reduced Peyer’s patches and small spleens. Antibiotic treatment significantly reduced the expression of antimicrobial factors and altered the expression of 517 genes in total in the colonic epithelium. Genes involved in cell cycle were significantly altered concomitant with reduced epithelial proliferative activity in situ assessed by Ki-67 expression, suggesting that commensal microbiota drives cellular proliferation in colonic epithelium. We present a robust protocol for depleting mice of their cultivatable intestinal microbiota with antibiotics by gavage and show that the biological effect of this depletion is phenotypic characteristics and epithelial gene expression profile similar to those of germ-free mice. Comparison of genome-wide gene expression of colon intestinal epithelial cells from mice subjected to microbiota depletion protocol against to control mice.
Project description:Transitory appearance of immune suppressive polymorphonuclear neutrophils (PMN) defined as myeloid-derived suppressor cells (PMN-MDSC) in newborns is important for their protection from inflammation associated with newly established gut microbiota. Here, we report that inhibition of the type I interferon (IFN1) pathway played a major role in regulation of PMN-MDSC suppressive activity during first weeks of life. Expression of the IFN1 receptor IFNAR1 was markedly lower in PMN-MDSC. However, in newborn mice, down-regulation of IFNAR1 was not sufficient to render PMN immune suppressive. That also required the presence of a positive signal from lactoferrin via its receptor LRP2. The latter effect was mediated via NF-kB activation, which was tempered by IFN1 in a manner that involved SOCS3. Thus, we discovered a mechanism of tight regulation of immune suppressive PMN-MDSC in newborns, which may be used in the development of therapies of neonatal pathologies
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.