The ubiquitin ligase tripartite-motif-protein 32 is induced in Duchenne muscular dystrophy.
Activation of the proteasome pathway is one of the secondary processes of cell damage, which ultimately lead to muscle degeneration and necrosis in Duchenne muscular dystrophy (DMD). In mdx mice, the proteasome inhibitor bortezomib up-regulates the membrane expression of members of the dystrophin complex and reduces the inflammatory reaction. However, chronic inhibition of the 26S proteasome may be toxic, as indicated by the systemic side-effects caused by this drug. Therefore, we sought to determine the components of the ubiquitin-proteasome pathway that are specifically activated in human dystrophin-deficient muscles. The analysis of a cohort of patients with genetically determined DMD or Becker muscular dystrophy (BMD) unveiled a selective up-regulation of the ubiquitin ligase tripartite motif-containing protein 32 (TRIM32). The induction of TRIM32 was due to a transcriptional effect and it correlated with disease severity in BMD patients. In contrast, atrogin1 and muscle RING-finger protein-1 (MuRF-1), which are strongly increased in distinct types of muscular atrophy, were not affected by the DMD dystrophic process. Knock-out models showed that TRIM32 is involved in ubiquitination of muscle cytoskeletal proteins as well as of protein inhibitor of activated STAT protein gamma (Piasγ) and N-myc downstream-regulated gene, two inhibitors of satellite cell proliferation and differentiation. Accordingly, we showed that in DMD/BMD muscle tissue, TRIM32 induction was more pronounced in regenerating myofibers rather than in necrotic muscle cells, thus pointing out a role of this protein in the regulation of human myoblast cell fate. This finding highlights TRIM32 as a possible therapeutic target to favor skeletal muscle regeneration in DMD patients.
Unit of Paediatric Neurology and Muscle Diseases, G. Gaslini Institute, Genoa, Italy.
Stefania
S
Assereto
Department of Oncology, IRCCS-Mario Negri Institute for Pharmacological Research, Milano, Italy.
Rosanna
R
Piccirillo
Unit of Paediatric Neurology and Muscle Diseases, G. Gaslini Institute, Genoa, Italy.
Serena
S
Baratto
Unit of Medical Genetics, G. Gaslini Institute, University of Genoa, Genoa, Italy.
Paolo
P
Scudieri
Unit of Paediatric Neurology and Muscle Diseases, G. Gaslini Institute, Genoa, Italy.
Chiara
C
Fiorillo
Unit of Paediatric Neurology and Muscle Diseases, G. Gaslini Institute, Genoa, Italy.
Manuela
M
Massacesi
Unit of Paediatric Neurology and Muscle Diseases, G. Gaslini Institute, Genoa, Italy.
Monica
M
Traverso
Unit of Medical Genetics, G. Gaslini Institute, University of Genoa, Genoa, Italy.
Luis J
LJ
Galietta
Department of Neuroscience, Center of Myology and Neurodegenerative Disorders, G. Gaslini Institute, Genoa, Italy.
Claudio
C
Bruno
Unit of Paediatric Neurology and Muscle Diseases, G. Gaslini Institute, Genoa, Italy.|Department of Neuroscience, and Pediatrics (DINOGMI), University of Genoa, Genoa, Italy.
Carlo
C
Minetti
Unit of Paediatric Neurology and Muscle Diseases, G. Gaslini Institute, Genoa, Italy.
Federico
F
Zara
Unit of Paediatric Neurology and Muscle Diseases, G. Gaslini Institute, Genoa, Italy.
Elisabetta
E
Gazzerro
D000818:Animals; D016022:Case-Control Studies; D006801:Humans; D008297:Male; D051379:Mice; D018101:Mice, Inbred mdx; D020388:Muscular Dystrophy, Duchenne / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D052097:Quadriceps Muscle / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012038:Regeneration; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics; D000070584:Tripartite Motif Proteins / Q000096:biosynthesis* / Q000235:genetics; D044767:Ubiquitin-Protein Ligases / Q000096:biosynthesis* / Q000235:genetics; D015854:Up-Regulation
D012333:RNA, Messenger; D014157:Transcription Factors; D000070584:Tripartite Motif Proteins; C094027:TRIM32 protein, human; D044767:Ubiquitin-Protein Ligases