Project description:Mutations in genes encoding nuclear envelope proteins lead to diseases known as nuclear envelopathies, characterized by skeletal muscle and heart abnormalities, such as Emery-Dreifuss Muscular Dystrophy (EDMD). The tissue-specific role of the nuclear envelope in the etiology of these diseases has not been extensively explored. We previously showed that global deletion of the muscle-specific nuclear envelope protein NET39 in mice leads to neonatal lethality due to skeletal muscle dysfunction. To study the potential role of the Net39 gene in adulthood, we generated a muscle-specific conditional knockout (cKO) of Net39 in mice. cKO mice recapitulated key skeletal muscle features of EDMD, including muscle wasting, impaired muscle contractility, abnormal myonuclear morphology, and DNA damage. The loss of Net39 rendered myoblasts hypersensitive to mechanical stretch, resulting in stretch-induced DNA damage. Net39 was downregulated in a mouse model of congenital myopathy, and restoration of Net39 expression through AAV gene delivery extended lifespan and ameliorated the muscle abnormalities. These findings establish NET39 as a direct contributor to the pathogenesis of EDMD by protecting against mechanical stress and DNA damage.
Project description:Mutations in genes encoding nuclear envelope proteins lead to diseases known as nuclear envelopathies, characterized by skeletal muscle and heart abnormalities, such as Emery-Dreifuss Muscular Dystrophy (EDMD). The tissue-specific role of the nuclear envelope in the etiology of these diseases has not been extensively explored. We previously showed that global deletion of the muscle-specific nuclear envelope protein NET39 in mice leads to neonatal lethality due to skeletal muscle dysfunction. To study the potential role of the Net39 gene in adulthood, we generated a muscle-specific conditional knockout (cKO) of Net39 in mice. cKO mice recapitulated key skeletal muscle features of EDMD, including muscle wasting, impaired muscle contractility, abnormal myonuclear morphology, and DNA damage. The loss of Net39 rendered myoblasts hypersensitive to mechanical stretch, resulting in stretch-induced DNA damage. Net39 was downregulated in a mouse model of congenital myopathy, and restoration of Net39 expression through AAV gene delivery extended lifespan and ameliorated the muscle abnormalities. These findings establish NET39 as a direct contributor to the pathogenesis of EDMD by protecting against mechanical stress and DNA damage.
Project description:Mutations in genes encoding nuclear envelope proteins lead to diseases known as nuclear envelopathies, characterized by skeletal muscle and heart abnormalities, such as Emery-Dreifuss Muscular Dystrophy (EDMD). The tissue-specific role of the nuclear envelope in the etiology of these diseases has not been extensively explored. We previously showed that global deletion of the muscle-specific nuclear envelope protein NET39 in mice leads to neonatal lethality due to skeletal muscle dysfunction. To study the potential role of the Net39 gene in adulthood, we generated a muscle-specific conditional knockout (cKO) of Net39 in mice. cKO mice recapitulated key skeletal muscle features of EDMD, including muscle wasting, impaired muscle contractility, abnormal myonuclear morphology, and DNA damage. The loss of Net39 rendered myoblasts hypersensitive to mechanical stretch, resulting in stretch-induced DNA damage. Net39 was downregulated in a mouse model of congenital myopathy, and restoration of Net39 expression through AAV gene delivery extended lifespan and ameliorated the muscle abnormalities. These findings establish NET39 as a direct contributor to the pathogenesis of EDMD by protecting against mechanical stress and DNA damage.
Project description:Emery-Dreifuss muscular dystrophy (EDMD) is a genetically and clinically variable disorder. Here we performed transcriptome analysis on 10 EDMD patients covering mutations in 7 EDMD-linked genes, compared to 2 healthy controls. Myoblasts were isolated from muscle biopsies and differentiated in-vitro for 6 days. Differentiated myotubes were isolated, total RNA extracted and the small <200 nt fraction sequenced. The genes and mutations included were: patient 1 (TMEM214, p.R179H), patient 2 (PLPP7/NET39, p.M92K), patient 3 (SUN1, p.G68D, p.G388S), patient 4 (SYNE1, p.6869*, p.6869*), patient 5 (EMD, p.S58Sfs*1), patient 6 (FHL1, c.688+1G>A), patient 7 (FHL1, p.C224W), patient 8 (FHL1, p.V280M), patient 9 (LMNA, p.T528K), patient 10 (LMNA, p.R571S).
Project description:Emery-Dreifuss muscular dystrophy (EDMD) is a genetically and clinically variable disorder. Here we performed transcriptome analysis on 10 EDMD patients covering mutations in 7 EDMD-linked genes, compared to 2 healthy controls. Myoblasts were isolated from muscle biopsies and differentiated in-vitro for 6 days. Differentiated myotubes were isolated, total RNA extracted, and mRNA sequenced. The genes and mutations included were: patient 1 (TMEM214, p.R179H), patient 2 (PLPP7/NET39, p.M92K), patient 3 (SUN1, p.G68D, p.G388S), patient 4 (SYNE1, p.6869*, p.6869*), patient 5 (EMD, p.S58Sfs*1), patient 6 (FHL1, c.688+1G>A), patient 7 (FHL1, p.C224W), patient 8 (FHL1, p.V280M), patient 9 (LMNA, p.T528K), patient 10 (LMNA, p.R571S). The patients were found to segregate into 3 subgroups, defined as: gp1 = patients 1,2,5,7 and 10; gp2 = patients 3,6, and 8; gp3 = patients 4 and 9.
Project description:Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant disorder linked to contractions of the D4Z4 repeat array in the subtelomeric region of chromosome 4q. By comparing genome-wide gene expression data from muscle biopsies of patients with FSHD to those of 11 other neuromuscular disorders, we intend to identify disease-specific changes which are more likely to be involved in the early stages of the disease progression. The data will help to identify pathological mechanisms involved in FSHD. Experiment Overall Design: Comparison of the profiles of FSHD to 13 other conditions for disease-specific changes. The 13 conditions are NHM (Normal healthy muscle) n=15; JDM (Juvenile dermatomyositis) n=25; HSP (Human spastic paraplegia) n=4; FSHD (facioscapulohumeral dystrophy) unaffected n=5, affected n=9; FKRP (Fukutin related protein deficiency) n=7; ED-L (Emery-Dreifuss muscular dystrophy, lamin A/C deficiency) n=4; ED-E (Emery-Dreifuss muscular dystrophy, emerin deficiency) n=4; DYSF (dysferlinopathy) n=10; DMD (Duchenne Muscular Dystrophy) n=10; CALP (Calpain-3 deficiency) n=10; BMD (Becker Muscular Dystrophy) n=5; AQM (Acute quadriplegic myopathy) n=5; ALS (Amyotrophic lateral sclerosis) n=9.