Project description:We compared differential gene expression in tracheal aspirates collected mechanically ventilated subjects with COVID-19 ARDS to gene expression in tracheal aspirates from: 1) subjects with ARDS from other casues and 2) mechanically ventilated controls without evidence of pulmonary disease.
Project description:The chicken gastrointestinal tract (GIT) harbours a complex microbial community, involved in several physiological processes such as host immunomodulation and feed digestion. Other studies were already performed to define the chicken gut metagenome and its fecal metaproteome. For the first time, the present study analysed dietary effects on the protein inventory of the microbiota in crop and ceca of broilers. We performed quantitative label-free metaproteomics by using 1D-gel electrophoresis coupled with LC-MS/MS to identify the structural and functional changes triggered by diets supplied with varying amount of mineral phosphorus (P) and microbial phytase (MP). Phylogenetic assessment based on label-free quantification (LFQ) values of the proteins identified Lactobacillaceae as the major family in the crop section regardless of the diet, whereas proteins belonging to the family Veillonellaceae increased with the P supplementation. Within the ceca section, proteins of Bacteroidaceae were more abundant in the P-supplied diets, whereas proteins of Eubacteriaceae decreased with the P-addition. Proteins of the Ruminococcaceae increasedraised with the amount of MP while proteins of Lactobacillaceae werewas more abundant in the MP-lacking diets. Classification of the identified proteins into COGs and KEGG pathways underlined a diverse microbiota activity depending on the dietary regimen, indicating a thriving microbial community in the case of P and MP supplementation, and stressed microbial community when no P and MP were supplied. Insights oninto the identified KEGG pathways, as well as comparison between the GIT sections, dietary treatments, and the bacterial families encoding for the pathways of interest are provided. T) harbours a complex microbial community, involved in several physiological processes such as host immunomodulation and feed digestion. Other studies were already performed to define the chicken gut metagenome and its fecal metaproteome. For the first time, the present study analysed dietary effects on the protein inventory of the microbiota in crop and ceca of broilers. We performed quantitative label-free metaproteomics by using 1D-gel electrophoresis coupled with LC-MS/MS to identify the structural and functional changes triggered by diets supplied with varying amount of mineral phosphorus (P) and microbial phytase (MP). Phylogenetic assessment based on label-free quantification (LFQ) values of the proteins identified Lactobacillaceae as the major family in the crop section regardless of the diet, whereas proteins belonging to the family Veillonellaceae increased with the P supplementation. Within the ceca section, proteins of Bacteroidaceae were more abundant in the P-supplied diets, whereas proteins of Eubacteriaceae decreased with the P-addition. Proteins of the Ruminococcaceae increasedraised with the amount of MP while proteins of Lactobacillaceae werewas more abundant in the MP-lacking diets. Classification of the identified proteins into COGs and KEGG pathways underlined a diverse microbiota activity depending on the dietary regimen, indicating a thriving microbial community in the case of P and MP supplementation, and stressed microbial community when no P and MP were supplied. Insights oninto the identified KEGG pathways, as well as comparison between the GIT sections, dietary treatments, and the bacterial families encoding for the pathways of interest are provided.
Project description:Rationale: Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory tract infections and hospitalizations in infants worldwide. Known risk factors, however, incompletely explain the variability of RSV disease severity among children. We postulate that severity of RSV infection is influenced in part by modulation of the host immune response by the local microbial ecosystem at the time of infection. Objectives: To define whether different nasopharyngeal microbiota profiles are associated with distinct host transcriptome profiles and severity in children with RSV infection. Methods: We analyzed the nasopharyngeal microbiota profiles of young children with mild and severe RSV disease and healthy matched controls by 16S-rRNA sequencing. In parallel, we analyzed whole blood gene expression profiles to study the relationship between microbial community composition, the RSV-induced host transcriptional response and clinical disease severity. Measurements and Main results: We identified five nasopharyngeal microbiota profiles characterized by enrichment of H. influenzae, Streptococcus, Corynebacterium, Moraxella or S. aureus. RSV infection and RSV hospitalization were positively associated with H. influenzae and Streptococcus, and negatively associated with S. aureus abundance, independent of age. The host response to RSV was defined by overexpression of interferon-related genes, and this was independent of the microbiota composition. On the other hand, transcriptome profiles of RSV infected children with H. influenzae and Streptococcus-dominated microbiota were characterized by greater overexpression of genes linked to toll-like receptor-signaling and neutrophil activation and were more frequently hospitalized Conclusions: Our data suggest an immunomodulatory role for the resident nasopharyngeal microbial community early in RSV infection, potentially affecting RSV disease severity.
Project description:We profiled transcriptome and accessible chromatin landscapes in intestinal epithelial cells (IECs) from mice reared in the presence or absence of microbiota. We show that regional differences in gene transcription along the intestinal tract were accompanied by major alterations in chromatin organization. Surprisingly, we discovered that microbiota modify host gene transcription in IECs without significantly impacting the accessible chromatin landscape. Instead, microbiota regulation of host gene transcription might be achieved by differential expression of specific TFs and enrichment of their binding sites in nucleosome depleted CRRs near target genes. Our results suggest that the chromatin landscape in IECs is pre-programmed by the host in a region-specific manner to permit responses to microbiota through binding of open CRRs by specific TFs. mRNA and accessible chromatin (DNase-seq) profiles from colonic and ileal IECs were compared between conventionally-raised (CR), germ-free (GF), and conventionalized (CV) C57BL/6 mice.
Project description:Proteases constitute the largest enzyme gene family in vertebrates with intracellular and secreted proteases having critical roles in cellular and organ physiology. Intestinal tract contains diverse set of proteases mediating digestion, microbial responses, epithelial and immune signaling. Transit of chyme through the intestinal tract results in significant suppression of proteases. Although endogenous protease inhibitors have been identified, the broader mechanisms underlying protease regulation in the intestinal tract remains unclear. The objective of this study was to determine microbial regulation of proteolytic activity in intestinal tract using phenotype of post-infection irritable bowel syndrome, a condition characterized by high fecal proteolytic activity. Proteases of host pancreatic origin (chymotrypsin like pancreatic elastase 2A, 3B and trypsin 2) drove proteolytic activity. Of the 14 differentially abundant taxa, high proteolytic activity state was characterized by complete absence of the commensal Alistipes putredinis. Germ free mice had very high proteolytic activity (10-fold of specific-pathogen free mice) which dropped significantly upon humanization with microbiota from healthy volunteers. In contrast, high proteolytic activity microbiota failed to inhibit it, a defect that corrected with fecal microbiota transplant as well as addition of A. putredinis. These mice also had increased intestinal permeability similar to that seen in patients. Microbiota β-glucuronidases mediate bilirubin deconjugation and unconjugated bilirubin is an inhibitor of serine proteases. We found that high proteolytic activity patients had lower urobilinogen levels, a product of bilirubin deconjugation. Mice colonized with β-glucuronidase overexpressing E. coli demonstrated significant inhibition of proteolytic activity and treatment with β-glucuronidase inhibitors increased it. The findings establish that specific commensal microbiota mediates effective inhibition of host pancreatic proteases and maintains intestinal barrier function through the production of β-glucuronidases. This suggests an important homeostatic role for commensal intestinal microbiota.