Biogerontology

, Volume 18, Issue 1, pp 85–95

l-Lysine suppresses myofibrillar protein degradation and autophagy in skeletal muscles of senescence-accelerated mouse prone 8

Research Article

Abstract

Sarcopenia is a condition of the loss of muscle mass that is associated with aging and that increases the risk for bedridden state, thereby warranting studies of interventions that attenuate sarcopenia. Here the effects of 2-month dietary l-lysine (Lys) supplementation (1.5–3.0 %) on myofibrillar protein degradation and major proteolytic systems were investigated in senescence-accelerated mouse prone 8 (SAMP8). At 36 weeks of age, skeletal muscle and lean body mass was reduced in SAMP8 when compared with control senescence-accelerated mouse resistant 1 (SAMR1). The myofibrillar protein degradation, which was evaluated by the release of 3-methylhistidine, was stimulated in SAMP8, and the autophagy activity, which was evaluated by light chain 3-II, was stimulated in the skeletal muscle of SAMP8. The activation of ubiquitin-proteasome system was not observed in the muscles of SAMP8. However, myofibrillar protein degradation and autophagic activity in skeletal muscles of SAMP8 were suppressed by dietary intake of 3.0 % Lys. The present data indicate that myofibrillar protein degradation by bulk autophagy is stimulated in the skeletal muscles of SAMP8 and that dietary Lys supplementation attenuates sarcopenia in SAMP8 by suppressing autophagic proteolysis.

Keywords

Sarcopenia Autophagy Ubiquitin proteasome system Skeletal muscle Lysine 

Abbreviations

GAPDH

Glyceraldehyde-3-phosphate dehydrogenase

LC3

Light chain 3

Lys

l-Lysine

MeHis

3-Methylhistidine

mTOR

Mammalian target of rapamycin

Mul1

Mitochondrial E3 ubiquitin protein ligase 1

MuRF1

Muscle ring-finger protein 1

PGC-1α

Peroxisome proliferator activated receptor γ co-activator 1α

qRT-PCR

Quantitative reverse transcription PCR

SAMP8

Senescence-accelerated mouse prone 8

SAMR1

Senescence-accelerated mouse resistant 1

S6K1

p70 ribosomal protein S6 kinase 1

UPS

Ubiquitin-proteasome system

4E-BP1

Eukaryotic initiation factor 4E binding protein 1

Copyright information

© Springer Science+Business Media Dordrecht 2016

Authors and Affiliations

  1. 1.Department of Bioresources Science, The United Graduate School of Agricultural SciencesIwate UniversityMoriokaJapan
  2. 2.Department of Biological Chemistry and Food Science, Graduate School of AgricultureIwate UniversityMoriokaJapan

Personalised recommendations