Analysis of candidate miRNAs detected in cystic fibrosis disease in patient nasal and serum samples

Cystic fibrosis (CF), caused by mutations in the cystic fibrosis transmembrane regulator (CFTR) gene, is an autosomal recessive inherited and common genetic disease. The CFTR protein, which is a chlorine channel, works dependent on cAMP and protein kinase A. The CFTR protein, which provides fluid homeostasis on the epithelial surface, is responsible for the regulation of other chlorine channels and epithelial sodium channels. It has been found that there are more than 2100 mutations in the CFTR gene in the studies conducted to date. Mutations classified depending on the function of the CFTR protein play an important role in the severity of the disease by affecting the stages of the CFTR protein such as synthesis, folding, transport, placement and proper functioning. The identification of CFTR mutations allows the diagnosis of the disease, but does not provide information about the severity, phenotype and progression of the disease. With the studies conducted in recent years, the findings that the differences observed in miRNA expressions, as well as the expressions of genes related to immune and inflammatory response, protein folding, ion transport and oxidative stress, affect the pathogenesis of the disease have increased. As a result of preliminary studies conducted in collaboration with Hacettepe University Faculty of Medicine Department of Medical Biology and Department of Child Health and Diseases Pulmonology Unit, siblings with severe and mild clinical severity were identified despite carrying the same mutation. Nasal swab samples were taken from the patient siblings with severe (n=2) and mild (n=2) course with F508del mutation. The RNAs obtained using nasal epithelial cells were performed using the miRNA Array method and the raw data obtained were analyzed with the Transcriptome Analysis Console (TAC) program. After the analysis, 4 miRNAs were identified, including common, MIR-449c-5p, mir-34c-3p, MIR-34c-5p and MIR-4793-3p, whose expression increased by 2 times or decreased by more than 2 times. Our aim in the proposed thesis study is to validate the 4 miRNAs obtained by our group as preliminary data in serum and nasal swab samples of CF patients with severe and mild course with F508del mutation, compare their expression, determine the target genes of the validated miRNAs and identify the pathways associated with the target genes. The obtained data will enable the determination of prognostic miRNAs, which will facilitate the early determination of the disease course in CF, and new pathways associated with CF pathogenesis can be elucidated.