Dux4 Target Gene Expression in Mouse Muscle Transplanted with Muscle Cells from FSHD Patients

Facioscapulohumeral Muscular Dystrophy (FSHD) is one of the most prevalent forms of muscular dystrophy. However, because of the unique nature of the genetic abnormality underlying the disease, there is currently no widely available laboratory model. In order to gain insights into FSHD molecular pathology, we developed a xenograft model by transplanting myogenic cells from patients with FSHD (4qA contractions) as well as from their unaffected relatives into the tibialis anterior muscles of immunodeficient mice. Our findings show that muscle xenografts derived from FSHD myogenic cells express Dux4 target genes, recapitulating the expression of these disease biomarkers in muscle biopsies of FSHD patients. FSHD muscle xenografts provide an animal model for investigations of the molecular pathogenesis of FSHD muscles and for drug development

Immortalized myogenic cells from congenital muscular dystrophy type1A patients recapitulate aberrant caspase activation in pathogenesis: a new tool for MDC1A research

BACKGROUND: Congenital muscular dystrophy Type 1A (MDC1A) is a severe, recessive disease of childhood onset that is caused by mutations in the LAMA2 gene encoding laminin-alpha2. Studies with both mouse models and primary cultures of human MDC1A myogenic cells suggest that aberrant activation of cell death is a significant contributor to pathogenesis in laminin-alpha2-deficiency. METHODS: To overcome the limited population doublings of primary cultures, we generated immortalized, clonal lines of human MDC1A myogenic cells via overexpression of both CDK4 and the telomerase catalytic component (human telomerase reverse transcriptase (hTERT)). RESULTS: The immortalized MDC1A myogenic cells proliferated indefinitely when cultured at low density in high serum growth medium, but retained the capacity to form multinucleate myotubes and express muscle-specific proteins when switched to low serum medium. When cultured in the absence of laminin, myotubes formed from immortalized MDC1A myoblasts, but not those formed from immortalized healthy or disease control human myoblasts, showed significantly increased activation of caspase-3. This pattern of aberrant caspase-3 activation in the immortalized cultures was similar to that found previously in primary MDC1A cultures and laminin-alpha2-deficient mice. CONCLUSIONS: Immortalized MDC1A myogenic cells provide a new resource for studies of pathogenetic mechanisms and for screening possible therapeutic approaches in laminin-alpha2-deficiency