Analisi dell'immuno-trascrittoma di cavallo nelle patologie IAD e RAO

The research project has been developed on the equine inflammatory respiratory diseases, which can be divided in Recurrent Airway Obstruction (RAO) and Inflammatory Airway Disease (IAD). The aim of this study was to investigate immune-related genes expression in the respiratory tract of IAD and RAO-affected horses. Clinical examination and endoscopy were performed. On the Broncho-Alveolar Lavage (BAL) fluid, obtained during endoscopy, cytological and microbiological analysis were performed to evaluate correlations between the gene expressions values and the clinical parameters. A first analysis was developed by real time RT-PCR comparing the gene expression profile of 10 immune-related target genes (IL-1ß, IL-6, IL-8, IL-13, IL-17, TNFa, INF?, TGF-ß1, NF?-ß and TRL 4) in the BAL of healthy horses and RAO-affected ones, on which sampling was performed twice within 15 days. The aim was to deepen the effects of the respiratory disease on the equine immune system and to assess a potential temporal evolution of the gene expression values and of the other parameters considered. In addition, biopsies of the bronchial tissue were obtained and subsequent, histological evaluation and gene expression analyses were performed. Six of the target genes showed a significant expression values increase in the RAO group compared to the control one. A positive statistical correlation between the amount of mucus in the airways and the expression of some genes investigated was found. Regarding inflammatory mediators expression in the biopsy tissue, neither of target genes was significantly differentially expressed between the RAO horses and the control group. The second part of the research project included also the study of IAD. On all horses, clinical investigations and assessments of gene expression profiles were carried out twice within 15 days, at the diagnosis moment and at the end of the pharmacological treatment. Considering the results of the first study, no biopsies of the respiratory tissue were performed. The development of a microarray platform specific for equine immune-related genes, provide a global view of the pathways involved in the IAD and RAO inflammatory response. The statistical analyses showed that 379 transcripts (55 up-regulated and 324 down-regulated) were significantly differentially expressed between the IAD group and control horses and 1763 genes (903 up-regulated and 860 down-regulated) between the RAO-affected horses and the healthy animals. Between IAD-affected horses and RAO animals, were showed significant differences of the respiratory rate at rest and of the amount of mucus in the airways. Some transcripts involved in the genesis, length and motility of the respiratory epithelium cilia, were down-regulated both in IAD and in RAO horses. In the IAD population, has been demonstrated the over-expression of genes coding for inflammatory mediators. Some of the transcripts up-regulated in the RAO group, are involved in the inflammatory response, bronchoconstriction, apoptosis and hypoxia pathway. In the same disease, some genes involved in the genesis of the protective muco-protein film of the respiratory epithelium were under-expressed. The analyses carried out by the software Gene Sets Enrichment Analysis (GSEA) showed that the pathway activated during human asthma, is also enriched in equine RAO, albeit marginally significant (False Discovery Rate