Effects of leucine supplementation on protein signalling pathways of protein syntheis in muscle soleus and EDL of young and old rats

• Grant number: 10/10852-6
• Support Opportunities: Regular Research Grants
• Start date: October 01, 2010
• End date: September 30, 2012
• Field of knowledge: Health Sciences - Nutrition
• Principal Investigator: Antonio Herbert Lancha Junior
• Grantee: Antonio Herbert Lancha Junior
• Host Institution: Escola de Educação Física e Esporte (EEFE). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: Daniela Fojo Seixas Chaves

Abstract

Amino acids have an important role in protein synthesis regulation and leucine is the aminoacid which hás a greater stimulatory potential. For this reason leucine supplementation has been used in situations in which protein synthesis is hindered such as CAQUEXIA and sarcopenia. However, older individuals do not respond the same way the young do and the doses need to be 2 ou 3 times greater in order to have the same effect. The molecular mechanisms involved in this lack of response are not known yet. Leucine stimulates an increase in protein synthesis through an increase in protein translation initiation, a process which involves several initiation factors, kinases and phosphatases. These protein activities are regulated through phosphorylation. This activation follows pathways that are dependent on the mTOR protein kinase and also via pathways that are independent of mTOR. The mechanism through which amino acids stimulate mTOR and/or the kinsases involved have not been completely elucidated yet. This work aims at making a comparative analysis of the phosphorylated proteins profile (phosphoproteome) of yong and old rats muscles stimulated by supplementation with low and high doses of leucine. The phosphorylated proteins are going to be isolated using Immobilized Metal Affinity Chromatography and the tyrosine phoshorylated proteins will be isolated by immunoprecipitation. The phosphorylated proteins profile will be compared using two-dimensional electrophoresis and the differentially expressed proteins will be identified using mass spectrometry. Furthermore, western-blot using phospho - specific antibodies against mTOR, p70s6k and 4EBP-1 will be performed. The comparion between the activated signalling pathways in young and old rats will allow the identification of kinases/phosphatases involved in the signalling pathways as well as the enzymes involved in such pathways in old muscles. Therefore this work will contribute to a better understanding of these pathways and also allow the development of better aminoacid supplementation protocols for different physiological conditions. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

CHAVES, DANIELA F. S.; CARVALHO, PAULO C.; LIMA, DIOGO B.; NICASTRO, HUMBERTO; LORENZETI, FABIO M.; SIQUEIRA-FILHO, MARIO; HIRABARA, SANDRO M.; ALVES, PAULO H. M.; MORESCO, JAMES J.; YATES, III, JOHN R.; et al. Comparative Proteomic Analysis of the Aging Soleus and Extensor Digitorum Longus Rat Muscles Using TMT Labeling and Mass Spectrometry. JOURNAL OF PROTEOME RESEARCH, v. 12, n. 10, p. 4532-4546, OCT 2013. (12/07319-0, 10/10852-6)

ANTONIO HERBERT LANCHA JUNIOR. Nutrição aplicada à atividade motora. Revista Paulista de Educação Física, v. 25, p. 45-51, 2011-12-00. (10/11221-0, 10/10852-6)

NICASTRO, HUMBERTO; ZANCHI, NELO E.; DA LUZ, CLAUDIA R.; DE MORAES, WILSON M. A. M.; RAMONA, PAMELLA; DE SIQUEIRA FILHO, MARIO A.; CHAVES, DANIELA F. S.; MEDEIROS, ALESSANDRA; BRUM, PATRICIA C.; DARDEVET, DOMINIQUE; et al. Effects of leucine supplementation and resistance exercise on dexamethasone-induced muscle atrophy and insulin resistance in rats. NUTRITION, v. 28, n. 4, p. 465-471, APR 2012. (10/10852-6, 10/07062-3, 11/04690-6)