Expression of microRNAs in the heart of spontaneously hypertensive rats (SHR) submitted to aerobic physical training

Author(s)

Marco Aurélio Amadeu

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Escola de Educação Física e Esportes (EEFE/BT)
• Defense date: 2011-11-22

Examining board members

Edilamar Menezes de Oliveira; Valerio Garrone Barauna; Paulo Rizzo Ramires

• Advisor: Edilamar Menezes de Oliveira

Abstract

Cardiac hypertrophy is a major mechanism of adaptation of the heart by the increased workload and may result from pathological stimuli such as high blood pressure leading to functional impairment or by physiological stimuli such as physical training, that on other hand promotes beneficial adaptations on the heart. In the last decade a new class of molecules, miRNAs, has been studied as regulators of gene expression in different cell type, including cardiomyocytes. However, few studies have investigated the miRNAs involved in adaptations to physical training. This study aimed to evaluate the effect of aerobic exercise training on expression profiling of miRNAs in the heart of spontaneously hypertensive rats (SHR) as well as select miRNAs with altered pattern in SHR and reversed by physical training and analyze their functional role through bioinformatics applications. The animals were divided into 3 groups: sedentary hypertensive rats (SHR-S), trained SHR (SHR-T) and sedentary Wistar Kyoto rats (WKY-S). The SHR-T group performed a swimming training protocol of 60 minutes, 5 times a week for 10 weeks and with overload of 5% of body weight in the tail. We analyzed hemodynamic (blood pressure, BP and resting heart rate, HR), functional (physical capacity, oxygen consumption and echocardiogram), biochemical (microarray and Real Time-PCR to miRNAs) and computational (prediction of targets and annotation cell signaling pathways) parameters. The main findings were: 1. The BP and HR decreased in SHR-T group compared to the sedentary animals; 2. The exercise tolerance and peak VO2 increased in SHR-T group; 3.Echocardiographic analysis showed that the E wave, A wave and E/A ratio improved in SHR-T group; 4. Microarray analysis found six different miRNAs expression profile in the comparison groups WKY-S, SHR-S and SHR-T; 5. Six miRNAs were altered in SHR-S and were reversed in the SHR-T (miR-1,22, 27a, 27b, 29c and 451); 7. Bioinformatics analysis showed that this miRNA cluster has multiple predicted targets in signaling pathways related to cardiac remodeling as MAPK, Wnt and TGF-beta and others genes associate to cytoskeletal structure and energetic metabolism. In conclusion, our results suggest that miRNAs: 1, 22, 27a, 27b, 29c and 451 can be controlling cell signaling pathways involved in the process of reversing the disease. These results open new perspectives on the use of these molecules as a therapeutic treatment (AU)

• FAPESP's process: 09/03264-3 - DIFERENCIAL EXPRESSION OF microRNAS IN SPONTANEOUSLY HYPERTENSIVE RAT HEART SUBMITTED AEROBIC PHISICAL TRAINING
• Grantee: Marco Aurelio Amadeu
• Support Opportunities: Scholarships in Brazil - Master