Role of MuRF-1 and MuRF2 upon skeletal muscle regeneration

• Grant number: 12/07018-0
• Support Opportunities: Regular Research Grants
• Start date: July 01, 2012
• End date: June 30, 2014
• Field of knowledge: Biological Sciences - Morphology - Anatomy
• Principal Investigator: Anselmo Sigari Moriscot
• Grantee: Anselmo Sigari Moriscot
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

MuRFs (Muscle Ring Fbox) are E3 ligases highly expressed in skeletal muscle and play a key role in the atrophic response. Additional roles of E3 ligases in skeletal muscle plasticity however have not been explored. The aim of this study is to understand the role of MuRFs in skeletal muscle regeneration, following a study initiated in a sabbatical period (details explained in the main body of the project). The role of MuRF1 and MuRF2 in skeletal muscle regeneration will be investigated using Knock out mice for MuRF1, MuRF2 and a double MuRF1/MuRF2 knock out. Firstly we will 1) confirm histological alterations and modifications in satellite cell number, previously found (preliminary results below). 2) We will evaluate gene expression of MuRF1, MurF2 and other E3 ligases such as MAFbx/Atrogin-1 and TRIM-32 along the regeneration process. 3) By usin knock out animals, we will address the role of MuRFs in several intracellular pathways known to be involved with the regenerative process, such as calcineurin, AkT/mTOR and B-catenin. 4) Miogenic factors will also be evaluated such as PAX-7, Myod and Myogenin in muscles from knock out animals. 5) We will also address if absence of MuRFs promote increased apoptosis in satellite cells during regeneration. 6) In a skeletal muscle primary cell culture model, we will address the role of MuRFs in vitro, by utilizing RNAi. By using those strategies, we will move forward the understanding of the role of MuRFs in skeletal muscle regeneration. In order to further advance, 7) we will consult a previously made two-hybrid system based list of interacting proteins with MuRFs. Depending on the information obtained we will proceed with ubiquitination assays to check for interactions with MuRFs. (AU)