title: Autophagy as a new therapeutic target in Duchenne muscular dystrophy.
abstract: A resolutive therapy for Duchene muscular dystrophy, a severe degenerative disease of the skeletal muscle, is still lacking. Because autophagy has been shown to be crucial in clearing dysfunctional organelles and in preventing tissue damage, we investigated its pathogenic role and its suitability as a target for new therapeutic interventions in Duchenne muscular dystrophy (DMD). Here we demonstrate that autophagy is severely impaired in muscles from patients affected by DMD and mdx mice, a model of the disease, with accumulation of damaged organelles. The defect in autophagy was accompanied by persistent activation via phosphorylation of Akt, mammalian target of rapamycin (mTOR) and of the autophagy-inhibiting pathways dependent on them, including the translation-initiation factor 4E-binding protein 1 and the ribosomal protein S6, and downregulation of the autophagy-inducing genes LC3, Atg12, Gabarapl1 and Bnip3. The defective autophagy was rescued in mdx mice by long-term exposure to a low-protein diet. The treatment led to normalisation of Akt and mTOR signalling; it also reduced significantly muscle inflammation, fibrosis and myofibre damage, leading to recovery of muscle function. This study highlights novel pathogenic aspects of DMD and suggests autophagy as a new effective therapeutic target. The treatment we propose can be safely applied and immediately tested for efficacy in humans.
authors.affiliation: Department of Biomedical and Clinical Sciences, University Hospital L. Sacco, Università di Milano, Milan, Italy.
authors.forename: C
authors.initials: C
authors.lastname: De Palma
authors.forename: F
authors.initials: F
authors.lastname: Morisi
authors.forename: S
authors.initials: S
authors.lastname: Cheli
authors.forename: S
authors.initials: S
authors.lastname: Pambianco
authors.forename: V
authors.initials: V
authors.lastname: Cappello
authors.forename: M
authors.initials: M
authors.lastname: Vezzoli
authors.forename: P
authors.initials: P
authors.lastname: Rovere-Querini
authors.forename: M
authors.initials: M
authors.lastname: Moggio
authors.forename: M
authors.initials: M
authors.lastname: Ripolone
authors.forename: M
authors.initials: M
authors.lastname: Francolini
authors.forename: M
authors.initials: M
authors.lastname: Sandri
authors.forename: E
authors.initials: E
authors.lastname: Clementi
mesh_terms: D000818:Animals; D001343:Autophagy; D004195:Disease Models, Animal; D006801:Humans; D008297:Male; D051379:Mice; D018101:Mice, Inbred mdx; D020388:Muscular Dystrophy, Duchenne / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology* / Q000628:therapy; D051058:Oncogene Protein v-akt / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D058570:TOR Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: C546842:MTOR protein, human; D051058:Oncogene Protein v-akt; D058570:TOR Serine-Threonine Kinases