Regulation of Duchenne muscular dystrophy through the obestatin/GPR39 system

Although autophagy impairment plays a significant role in the pathogenesis of Duchenne muscular dystrophy (DMD), little is known about the mechanisms by which the autophagic machinery and related signals are influenced by stressors connected to muscular dystrophy. In this work, we describe the unexp...

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Bibliographic Details
Author: Fernández Barreiro, Fátima
Format: doctoral thesis
Publication Date:2025
Country:España
Institution:Universidad de Santiago de Compostela (USC)
Repository:Minerva. Repositorio Institucional de la Universidad de Santiago de Compostela
Language:English
OAI Identifier:oai:minerva.usc.gal:10347/42101
Online Access:https://hdl.handle.net/10347/42101
Access Level:Open access
Keyword:obestatin signaling
Duchenne muscular dystrophy
autophagy
skeletal muscle
muscular dystrophy
241104 Fisiología endocrina
241108 Metabolismo humano
241003 Citología humana
Description
Summary:Although autophagy impairment plays a significant role in the pathogenesis of Duchenne muscular dystrophy (DMD), little is known about the mechanisms by which the autophagic machinery and related signals are influenced by stressors connected to muscular dystrophy. In this work, we describe the unexpected finding whereby in the dystrophin-deficient mdx mice and in human immortalized DMD myotubes, the obestatin/GPR39 system activates mTOR concurrently with AMPK to control protein synthesis, ubiquitin-proteasome system, and autophagy-lysosome system. Autophagy-derived amino acids enhance mTOR activity, thereby counteracting muscle wasting in DMD. The pattern of post-translational modifications of the E3 ligase NEDD4-L, including NEDD4-L tyrosine phosphorylation and autoubiquitination, is postulated as the major trigger to activate the autophagy process in response to obestatin. NEDD4-L employs different approaches to coordinate the VPS34 and ULK1 complexes.