Project description:Conventional laboratory mice housed under specific pathogen-free (SPF) conditions are the standard model in biomedical research. However, in the past years, many published results involving rodents have been considered irreproducible, raising concerns about the suitability of mice as model organisms. Emerging evidence indicates that variations in SPF microbiota contribute significantly to data variability across different laboratories. Despite efforts to standardize the microbiota, current microbial consortia lack the complexity and resilience needed to replicate interactions in free-living mammals. We present a standardizable and feasible approach for transplanting natural gut microbiota from wildlings into conventional laboratory mice. After engraftment, these TXwildlings adopt a structural and functional wildling-like microbiota and host physiology toward a more mature immune system, with characteristics similar to those of adult humans. We anticipate that using wild mouse-derived microbiota as standard for laboratory mouse models will improve the reproducibility and generalizability of basic and preclinical biomedical research.
Project description:The leukocyte NADPH oxidase 2 (NOX2) plays a key role in pathogen killing and immunoregulation. Genetic defects in NOX2 result in chronic granulomatous disease (CGD), associated with microbial infections and inflammatory disorders, often involving the lung. Alveolar macrophages (AM) are the predominant immune cell in the airways at steady state, and limiting their activation is important given constant exposure to inhaled materials, yet the importance of NOX2 in this process is not well-understood. Here, we show a previously undescribed role for NOX2 in maintaining lung homeostasis by suppressing AM activation, as studied using CGD mice or mice with selective loss of NOX2 primarily in macrophages. AM lacking NOX2 have increased cytokine responses to TLR2 and TLR4 stimulation ex vivo. Moreover, between 4 and 12 weeks of age, mice with global NOX2 deletion developed an activated CD11bhigh subset of AM with epigenetic and transcriptional profiles reflecting immune activation compared to WT AM. The presence of CD11bhigh AM in CGD mice correlated with increased numbers of alveolar neutrophils and proinflammatory cytokines at steady state as well as increased lung inflammation following insults. Moreover, deletion of NOX2 primarily in macrophages was sufficient for mice to develop an activated CD11bhigh AM subset and accompanying pro-inflammatory sequela. Additionally, we showed that the altered resident macrophage transcriptional profile in the absence of NOX2 is tissue-specific as these changes were not seen in resident peritoneal macrophages. Thus, these data demonstrate that absence of NOX2 in alveolar macrophages leads to their pro-inflammatory remodeling and dysregulates alveolar homeostasis.
Project description:This study aimed to analyze changes in gut microbiota composition in mice after transplantation of fecal microbiota (FMT, N = 6) from the feces of NSCLC patients by analyzing fecal content using 16S rRNA sequencing, 10 days after transplantation. Specific-pathogen-free (SPF) mice were used for each experiments (N=4) as controls.
Project description:Gut microbiota dysbiosis characterizes systemic metabolic alteration, yet its causality is debated. To address this issue, we transplanted antibiotic-free conventional wild-type mice with either dysbiotic (“obese”) or eubiotic (“lean”) gut microbiota and fed them either a NC or a 72%HFD. We report that, on NC, obese gut microbiota transplantation reduces hepatic gluconeogenesis with decreased hepatic PEPCK activity, compared to non-transplanted mice. Of note, this phenotype is blunted in conventional NOD2KO mice. By contrast, lean microbiota transplantation did not affect hepatic gluconeogenesis. In addition, obese microbiota transplantation changed both gut microbiota and microbiome of recipient mice. Interestingly, hepatic gluconeogenesis, PEPCK and G6Pase activity were reduced even once mice transplanted with the obese gut microbiota were fed a 72%HFD, together with reduced fed glycaemia and adiposity compared to non-transplanted mice. Notably, changes in gut microbiota and microbiome induced by the transplantation were still detectable on 72%HFD. Finally, we report that obese gut microbiota transplantation may impact on hepatic metabolism and even prevent HFD-increased hepatic gluconeogenesis. Our findings may provide a new vision of gut microbiota dysbiosis, useful for a better understanding of the aetiology of metabolic diseases. all livers are from NC-fed mice only.
Project description:Microbiota dysbiosis has been reported to contribute to the pathogenesis of colitis, to demonstrate whether IL-17D protects against DSS-induced colitis through regulation of microflora, we performed 16S rRNA sequencing in feces from WT and Il17d-deficient mice. Our data indicate that Il17d deficiency results in microbiota dysibiosis in both steady state and DSS-induced colitis.
Project description:The gut microbiota impacts many aspects of host biology including immune function. One hypothesis is that microbial communities induce epigenetic changes with accompanying alterations in chromatin accessibility, providing a mechanism that allows a community to have sustained host effects even in the face of its structural or functional variation. We used ATAC-seq to define chromatin accessibility in predicted enhancer regions of intestinal αβ+ and γδ+ intraepithelial lymphocytes (IELs) purified from germ-free mice, their conventionally-raised (CONV-R) counterparts, and mice reared GF and then colonized with a CONV-R gut microbiota at the end of the suckling-weaning transition. Characterizing genes adjacent to traditional enhancers and super-enhancers revealed signaling networks, metabolic pathways, and enhancer-associated transcription factors affected by the microbiota. Our results support the notion that epigenetic modifications help define microbial community-affiliated functional features of host immune cell lineages.