Expression profiling FSHD vs. control myoblasts and myotubes. Homo sapiens

The gene expression pathways leading to muscle pathology in facioscapulohumeral dystrophy (FSHD) remain to be elucidated. This muscular dystrophy is caused by a contraction of an array of tandem 3.3-kb repeats (D4Z4) at 4q35.2. We compared expression of control and FSHD myoblasts and myotubes (three preparations each) on exon microarrays (Affymetrix Human Exon 1.0 ST) and validated FSHD-specific differences for representative genes by qRT-PCR on additional myoblast cell strains. The FSHD and control myoblasts used for these experiments were shown to grow and differentiate into myotubes equally efficiently as control myoblasts. There were no significant FSHD-control differences in RNA levels for MYOD1 and MYOG at the myoblast and myotube stages and for MYF5 and MYF6 at the myoblast stage. In contrast, 295 other genes were dysregulated at least 2-fold in FSHD vs. control myoblasts (p 85% desmin-positive cells as determined with an antibody preparation confirmed to have selectivity for myogenic cells (Labvision/Thermo Scientific) using DAPI counterstaining. The myotube preparations had >70% of the nuclei in desmin-positive cells containing more than 2 nuclei per cell. Five of the six preparations for the microarray analysis (all but FM1795) were also immunostained with a monoclonal antibody to myosin heavy chain (MF20, a gift of Stephen D. Hauschka) and had >70% of the nuclei in multinucleated myosin heavy chain-positive cells.