Project description:Matrix metalloprotease (MMP) -2 has been reported to be up-regulated in skeletal muscle in the lethal X-linked muscle disorder Duchenne muscular dystrophy (DMD), which is caused by loss of dystrophin. However, the role of MMP-2 in dystrophin-deficient muscle is not well known. The aim of this study was to verify the role of MMP-2 in dystrophin-deficient muscle by using mdx mice with genetic ablation of MMP-2 (mdx/MMP-2-/-). Gene expression profiles were analyzed in the skeletal muscle of mdx and mdx/MMP-2-/- mice at 1 and 3 months of age.
Project description:Matrix metalloprotease (MMP) -2 has been reported to be up-regulated in skeletal muscle in the lethal X-linked muscle disorder Duchenne muscular dystrophy (DMD), which is caused by loss of dystrophin. However, the role of MMP-2 in dystrophin-deficient muscle is not well known. The aim of this study was to verify the role of MMP-2 in dystrophin-deficient muscle by using mdx mice with genetic ablation of MMP-2 (mdx/MMP-2-/-). Gene expression profiles were analyzed in the skeletal muscle of mdx and mdx/MMP-2-/- mice at 1 and 3 months of age. Tibialis anterior muscle was isolated from four groups of mice (mdx and mdx/MMP-2-/- mice at 1 and 3 months of age). Total RNA was purified and prepared for hybridization to Affymetrix Mouse Genome 430 2.0 arrays (Affymetrix Inc., Santa Clara, CA, USA) using Affymetrix reagents and protocols. The mRNA levels of differentially expressed genes from gene chip analysis were confirmed by quantitative real-time PCR assay.
Project description:Dystrophin proteomic regulation in Muscular Dystrophies (MD) remains unclear. We report that a long noncoding RNA (lncRNA) H19 associates with dystrophin. To investigate the biological roles of this interaction in vivo, we performed mass spectrometry analysis of dystrophin and its associated proteins in H19-proficient and -deficient C2C12 myotubes. Mass spectrometry data indicated that in H19-proficient myotubes, dystrophin associates with components of dystrophin-associated protein complex (DPC); however, in H19-deficient myotubes, dystrophin associated with UBA1, UB2G1, TRIM63 ubiquitin E3 ligase and ubiquitin. In H19-deficient myotubes, dystrophin was post-translationally modified with K48-linked poly-ubiquitination at Lys3577 (referred to as Ub-DMD). This mass spectrometry study demonstrated that lncRNA H19, associates with dystrophin and inhibits E3 ligase-dependent Ub-DMD formation and its subsequent proteasomal degradation. Based on this study, H19 RNA oligonucleotides conjugated with a muscle homing ligand Agrin (referred to as AGR-H19) and Nifenazone, a TRIM63-specific small molecule inhibitor, reverses the dystrophin degradation in iPSC-derived skeletal muscle cells from Becker Muscular Dystrophy patients. Furthermore,treatment of mdx mice with exon-skipping reagent, in combination with either AGR-H19 or Nifenazone, dramatically stablized dystrophin, preserved skeletal/cardiac muscle histology, and improved strength/heart function. In summary, this mass spectrometry study paves the way to meaningful targeted therapeutics for BMD and certain DMD patients.
Project description:Duchenne muscular dystrophy (DMD) is caused by mutations in the X-linked dystrophin (DMD) gene. The absence of dystrophin protein leads to progressive muscle weakness and wasting, disability and death. To establish a tailored large animal model of DMD, we deleted DMD exon 52 in male pig cells by gene targeting and generated offspring by nuclear transfer. DMD pigs exhibit absence of dystrophin in skeletal muscles, increased serum creatine kinase levels, progressive dystrophic changes of skeletal muscles, impaired mobility, muscle weakness, and a maximum life span of 3 months due to respiratory impairment. To address the accelerated development of muscular dystrophy in DMD pigs as compared to human patients, we performed a genome-wide transcriptome study of M. biceps femoris samples from 2-day-old and 3-month-old DMD and age-matched wild-type pigs. The transcriptome changes in 3-month-old DMD pigs were in good accordance with the findings of gene expression profiles in human DMD, reflecting the processes of degeneration, regeneration, inflammation, fibrosis, and impaired metabolic activity. The transcriptome profile of 2-day-old DMD pigs pointed towards increased protein and DNA catabolism, reduced extracellular matrix formation and cell proliferation and showed similarities with transcriptome changes induced by exercise injury in muscle. Our transcriptome studies provide new insights into congenital changes associated with dystrophin deficiency and secondary complications arising during postnatal development. Thus the DMD pig is a useful model to determine the hierarchy of physiological derangements in dystrophin-deficient muscle. 13 samples, two conditions, two age-groups, 3-4 biological replicates