Project description:Alterations of the bacterial ocular surface microbiome are found in both eyes of horses with unilateral infectious ulcerative keratitis
Project description:In 2005, we determined the glyco-gene expression profile of three normal subjects ( www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE27593). This led to information on the biosynthesis of mucin O-glycans and glycoproteins that may be involved in the protection of the ocular surface. The interaction of the most highly expressed glycoprotein identified by the glyco-gene chip, galectin-3, with other ligands at the ocular surface (i.e., mucin O-glycans), is now under intense study in our laboratory, and has lead to a collaboration with another group in the glycobiology field. Patients with dry eye disease have an alteration of mucin O-glycans at the ocular surface, but the molecular mechanism(s) leading to this alteration remain unknown. In this experiment we (i) pooled three pathological samples per chip to reduce variability, and (ii) used three additional chips to include pooled control samples (normal subjects). Currently, we have RNA from 9 patients with dry eye disease, which have been divided it in 3 groups (D1, D2, and D3)—each group containing RNA pooled from 3 patients. We request three additional chips to include control samples (normal subjects). At this moment, we have RNA from 9 normal subjects, which have been divided it in 3 groups (N1, N2, and N3)—each group containing RNA pooled from 3 normal subjects. RNA was extracted in Trizol, purified using RNeasy column, and dissolved in water were sent to Microarray Core (E). The RNA was amplified, labeled, and hybridized to the GLYCOv3 microarrays. Data Analysis was done by Microarray Core (E).
Project description:Dry eye is a common ocular inflammatory disorder characterized by tear film instability and reduced tear production. There is increasing evidence that homeostasis of the ocular surface is impacted by the intestinal microbiome. We are interested in investigating the potential role of microbially produced small molecules in mediating the interaction between the intestinal microbiota and the ocular surface. One such molecule is butyrate, a short-chain fatty acid (SCFA) produced by certain members of the gut microbiota through fermentation of dietary fiber. We have shown that oral administration of tributyrin, a prodrug form of butyrate, is protective of the ocular surface in mice undergoing desiccating stress. To gain insight into the mechanism, we analyzed gene expression in conjunctival tissue from mice treated with either tributyrgn or vehicle control.
Project description:Gut microbiome research is rapidly moving towards the functional characterization of the microbiota by means of shotgun meta-omics. Here, we selected a cohort of healthy subjects from an indigenous and monitored Sardinian population to analyze their gut microbiota using both shotgun metagenomics and shotgun metaproteomics. We found a considerable divergence between genetic potential and functional activity of the human healthy gut microbiota, in spite of a quite comparable taxonomic structure revealed by the two approaches. Investigation of inter-individual variability of taxonomic features revealed Bacteroides and Akkermansia as remarkably conserved and variable in abundance within the population, respectively. Firmicutes-driven butyrogenesis (mainly due to Faecalibacterium spp.) was shown to be the functional activity with the higher expression rate and the lower inter-individual variability in the study cohort, highlighting the key importance of the biosynthesis of this microbial by-product for the gut homeostasis. The taxon-specific contribution to functional activities and metabolic tasks was also examined, giving insights into the peculiar role of several gut microbiota members in carbohydrate metabolism (including polysaccharide degradation, glycan transport, glycolysis and short-chain fatty acid production). In conclusion, our results provide useful indications regarding the main functions actively exerted by the gut microbiota members of a healthy human cohort, and support metaproteomics as a valuable approach to investigate the functional role of the gut microbiota in health and disease.