Influência das vias de sinalização mTOR, STAT 3 e STAT 6 na gravidade da bronquiolite aguda

Abstract

Introduction: acute bronchiolitis (AB) is an inflammatory disease of the airways considered the most common pathology of the lower respiratory tract in childhood. Responsible for a large number of hospitalizations in infants is one of the leading respiratory diseases worldwide, raising the costs of health care in infants. According to epidemiological data, between 75,000 and 125,000 children are hospitalized in the United States each year with infections caused by respiratory syncytial virus (RSV), accounting for approximately 25% of pediatric pneumonia and up to 70% of hospitalizations for acute bronchiolitis. Children with deficiencies in cell-mediated immunity can develop more severe and prolonged infections. Activation of the mTOR, STAT-3 and STAT-6 signaling pathways have been identified as key regulators in different functions of the immune system. The aim of this study was to investigate the relationship between the gene expression of mTOR, STAT-3, STAT-6 and AB severity. Methods: it is a cohort study that included a group of infants less than 12 months old with AB admitted to a tertiary hospital in Porto Alegre, Brazil. Nasopharyngeal lavage was collected from all patients and stored in Trizol solution at -80ºC at the Biomedical Research Institute (IPB) of PUCRS for subsequent extraction of RNA and cDNA synthesis. Specific primers were used to verify the relative expression of mTOR, STAT-3 and STAT-6 by means of real-time PCR. The results obtained were correlated with AB severity markers such as hospitalization time and wheezing time. Results: for the analysis of expression of the mTOR signaling protein and transcription factors STAT-3 and STAT-6, 23 patients hospitalized with AB were included. A general correlation was made between clinical markers (days of hospitalization and days of wheezing) and expression of signaling pathways. Data were stratified according to severity markers and showed a trend towards decreased mTOR expression in patients with a wheezing time equal to or greater than 5 days (r = -0.702 and p = 0.024). However, the STAT-3 and STAT-6 signaling pathways were not correlated with AB severity factors when applied in this group of patients. Conclusion: transcription factors are essential for generating effective immune responses. mTOR, STAT-3 and STAT-6 participate in the expression of a variety of genes in response to cellular stimuli and may play a key role in the manifestation of the disease. Our data demonstrate the decrease in mTOR expression, with improvement in clinical markers of severity, but other studies are needed to reinforce this finding.