Project description:Background and aims. The etiopathology of inflammatory bowel diseases is still poorly understood. To date, only few little data are available on the microbiota composition in ulcerative colitis (UC), representing a major subform of inflammatory bowel diseases. Currently, one of the main challenges is to unravel the interactions between genetics and environmental factors in the onset or during the progression and maintenance of the disease. The aim of the present study was to analyse twin pairs discordant for UC for both gut microbiota dysbiosis and host expression profiles at a mucosal level and to get insight into the functional genomic crosstalk between microbiota and mucosal epithelium in vivo. Methods. Biopsies were sampled from the sigmoid colon of both healthy and diseased siblings from UC discordant twin pairs but also from healthy twins. Microbiota profiles were assessed by 16S rDNA libraries while mRNA expression profiles were analysed from the same volunteers using Affymetrix microarrays. Results. UC patients showed a dysbiotic microbiota with lower diversity and more species belonging to Actinobacteria and Proteobacteria phyla. On the contrary, their healthy siblingsM-bM-^@M-^Y microbiota contained more bacteria from the Lachnospiracea and Ruminococcaceae family than did healthy individuals . Sixty-three host transcripts significantly correlated with bacterial genera in healthy individuals whereas only 43 and 32 correlated with bacteria in healthy and UC siblings from discordant pairs, respectively. Several transcripts related to oxidative and immune responses were differentially expressed between unaffected and UC siblings. Conclusion. A loss of crosstalk between gut microbiota and host was highlighted in UC patients. This defect was also striking in healthy siblings from discordant pairs, as was the lower biodiversity within the microbiota. Our results suggest disease-relevant interactions between host transcriptome and microbiota. Moreover, unusual aerobic bacteria were noticed in UC mucosal microbiota, whereas healthy siblings from discordant pairs had higher percentages of potentially beneficialusual commensal bacterial species. Paired samples (twins) were analyzed to obtain data independent of genetic variation
Project description:Idiopathic pulmonary fibrosis (IPF) is the prototypic progressive fibrotic lung disease with a median survival of 2-4 years. Injury to and/or dysfunction of alveolar epithelium are strongly implicated in IPF disease initiation, but what factors determine why fibrosis progresses rather than normal tissue repair occurs remain poorly understood. We previously demonstrated that ZEB1-mediated epithelial-mesenchymal transition (EMT) in human alveolar epithelial type II (ATII) cells augments TGF-β-induced profibrogenic responses in underlying lung fibroblasts by paracrine signalling. Here we investigated bi-directional epithelial-mesenchymal crosstalk and its potential to drive fibrosis progression. RNA sequencing (RNA-seq) of lung fibroblasts exposed to conditioned media from ATII cells undergoing RAS-induced EMT identified many differentially expressed genes including those involved in cell migration and extracellular matrix (ECM) regulation. We confirmed that paracrine signalling between AS-activated ATII cells and fibroblasts augmented fibroblast recruitment and demonstrated that this involved a ZEB1-tissue plasminogen activator (tPA) axis. In a reciprocal fashion, paracrine signalling from TGF-β-activated lung fibroblasts or IPF fibroblasts induced RAS activation in ATII cells, at least partially via the secreted protein, SPARC. Together these data identify that aberrant bi-directional epithelial-mesenchymal crosstalk in IPF drives a chronic feedback loop that maintains a wound-healing phenotype and provides self-sustaining pro-fibrotic signals.
Project description:Remodeling of the gut microbiota is implicated in various metabolic and inflammatory diseases of the gastrointestinal tract. We hypothesized that the gut microbiota affects the DNA methylation profile of intestinal epithelial cells (IECs) which could, in turn, alter intestinal function. Here, we used mass spectrometry and methylated DNA capture to respectively investigate global and genome-wide DNA methylation of intestinal epithelial cells from germ-free (GF) and conventionally raised mice (CONV-R). In colonic IECs from GF mice, DNA was markedly hypermethylated. This was associated with a dramatic loss of Ten-Eleven-Translocation activity, a lower DNA methyltransferase activity and lower circulating levels of the one carbon metabolites cobalamin and folate. At the gene level, we found an enrichment for differentially methylated regions at proximity of genes regulating cytotoxicity of Natural Killer cells (FDR < 8.9E-6), notably members of the natural killer group 2 member D ligand superfamily Raet. Our results suggest that altered activity of methylation-modifying enzymes in GF mice influences the IEC epigenome at genes involved in the crosstalk between intestinal and immune cells. Epigenetic reprogramming of IECs by the gut microbiota may modulate intestinal function in diseases associated with altered gut microbiota.
Project description:To study bi-directional signaling between cancer-associated fibroblasts (CAFs) and cancer cells, we used stable isotope labeling by amino acids in cell culture (SILAC) to determine changes in tyrosine phosphorylation upon direct contact of the two cell types.
Project description:Background and aims. The etiopathology of inflammatory bowel diseases is still poorly understood. To date, only few little data are available on the microbiota composition in ulcerative colitis (UC), representing a major subform of inflammatory bowel diseases. Currently, one of the main challenges is to unravel the interactions between genetics and environmental factors in the onset or during the progression and maintenance of the disease. The aim of the present study was to analyse twin pairs discordant for UC for both gut microbiota dysbiosis and host expression profiles at a mucosal level and to get insight into the functional genomic crosstalk between microbiota and mucosal epithelium in vivo. Methods. Biopsies were sampled from the sigmoid colon of both healthy and diseased siblings from UC discordant twin pairs but also from healthy twins. Microbiota profiles were assessed by 16S rDNA libraries while mRNA expression profiles were analysed from the same volunteers using Affymetrix microarrays. Results. UC patients showed a dysbiotic microbiota with lower diversity and more species belonging to Actinobacteria and Proteobacteria phyla. On the contrary, their healthy siblings’ microbiota contained more bacteria from the Lachnospiracea and Ruminococcaceae family than did healthy individuals . Sixty-three host transcripts significantly correlated with bacterial genera in healthy individuals whereas only 43 and 32 correlated with bacteria in healthy and UC siblings from discordant pairs, respectively. Several transcripts related to oxidative and immune responses were differentially expressed between unaffected and UC siblings. Conclusion. A loss of crosstalk between gut microbiota and host was highlighted in UC patients. This defect was also striking in healthy siblings from discordant pairs, as was the lower biodiversity within the microbiota. Our results suggest disease-relevant interactions between host transcriptome and microbiota. Moreover, unusual aerobic bacteria were noticed in UC mucosal microbiota, whereas healthy siblings from discordant pairs had higher percentages of potentially beneficialusual commensal bacterial species.
Project description:Gut microbiota plays an important role during early development via bidirectional gut- brain signaling. We aimed to explore the potential link between gut microbiota/gut derived metabolites and sympathoadrenal stress responsivity