Suppression of mTORC1 activation in acid-α-glucosidase-deficient cells and mice is ameliorated by leucine supplementation.
Am J Physiol Regul Integr Comp Physiol
; 307(10): R1251-9, 2014 Nov 15.
Article
em En
| MEDLINE
| ID: mdl-25231351
ABSTRACT
Pompe disease is due to a deficiency in acid-α-glucosidase (GAA) and results in debilitating skeletal muscle wasting, characterized by the accumulation of glycogen and autophagic vesicles. Given the role of lysosomes as a platform for mTORC1 activation, we examined mTORC1 activity in models of Pompe disease. GAA-knockdown C2C12 myoblasts and GAA-deficient human skin fibroblasts of infantile Pompe patients were found to have decreased mTORC1 activation. Treatment with the cell-permeable leucine analog L-leucyl-L-leucine methyl ester restored mTORC1 activation. In vivo, Pompe mice also displayed reduced basal and leucine-stimulated mTORC1 activation in skeletal muscle, whereas treatment with a combination of insulin and leucine normalized mTORC1 activation. Chronic leucine feeding restored basal and leucine-stimulated mTORC1 activation, while partially protecting Pompe mice from developing kyphosis and the decline in muscle mass. Leucine-treated Pompe mice showed increased spontaneous activity and running capacity, with reduced muscle protein breakdown and glycogen accumulation. Together, these data demonstrate that GAA deficiency results in reduced mTORC1 activation that is partly responsible for the skeletal muscle wasting phenotype. Moreover, mTORC1 stimulation by dietary leucine supplementation prevented some of the detrimental skeletal muscle dysfunction that occurs in the Pompe disease mouse model.
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Base de dados:
MEDLINE
Assunto principal:
Doença de Depósito de Glicogênio Tipo II
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Músculo Esquelético
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Suplementos Nutricionais
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Complexos Multiproteicos
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Dipeptídeos
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Alfa-Glucosidases
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Serina-Treonina Quinases TOR
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article