Kistik Fibrozis Patogenezinde Aday Mirna ve Hedef Genlerinin Biyoinformatik Araçlarla Tanımlanması

Abstract

Cystic fibrosis (CF) is a very common autosomal recessive genetic disease caused by mutations in the cystic fibrosis transmembrane regulator (CFTR) gene. Although disease severity is associated with the effect of mutations on the CFTR protein, it is known that epigenetic factors also affect disease severity in patients carrying the same mutation. As a result of the preliminary studies, siblings with different disease severity were identified despite carrying the same mutation that was carried out in cooperation with Hacettepe University Faculty of Medicine, Department of Medical Biology and Department of Pediatrics, Chest Diseases. In the preliminary study, differentially expressed genes and pathways were determined between nasal brushing of affected siblings who have different disease severity (severe/mild) by using real-time PCR based cystic fibrosis PCR array. This thesis aims to identify common miRNAs and the target genes to explain the phenotypic changes, which show expression differences in siblings with different clinical severity despite having the same CFTR mutation. For this purpose, miRNA array raw data carried out in Hacettepe University Comprehensive Research Project (TSA 201816629) were defined with different bioinformatic tools, candidate miRNAs that may cause clinical heterogeneity among siblings and pathways related to their targets were determined. Raw data of Affymetrix miRNA 4.0 Array microarray results were analysed using BRB-ArrayTool, TAC 4.0 and MeV programs and candidate miRNAs were selected. As a result of the analyses, miR-145-5p was more expressed in patients with severe siblings and Class IV mutation patients with severe siblings than mild ones. After the pathway analysis of the target genes of miR-145-5p, a common ErbB signalling pathway was obtained in miRWalk and miRNET programs. The status of candidate genes included in the outputs of our preliminary study as miRNA targets was also investigated. The IL-17 signalling pathway which was compatible with CF pathology and had the highest p value was defined for miR-145-5p. In addition, miR-92a-3p expression was increased in patients compared to control individuals. As a result of the pathway analysis of the target genes of miR-92a-3p, the endocytosis pathway containing the most target genes was obtained in miRWalk and miRNET programs. This study will facilitate the clinical course of CF patients and the early detection of other diseases accompanying CF, identify a prognostic miRNA signature, and illuminate new pathways associated with the pathogenesis of the disease.