rAAV-mediated TCAP Gene Replacement Therapy: A Promising Therapeutic Approach for LGMDR7


Topic:

Translational Research

Poster Number: 166

Author(s):

Liubov Gushchina, PhD, Nationwide Children's Hospital, Adrienne Bradley, Nationwide Children's Hospital, Sydney Casey, The Abigail Wexner Research Institute at Nationwide Children's Hospita, Ben Petrykowski, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Jacob Lay, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Emma Frair, Nationwide Children's Hospital, Charles Emerson, PhD, University of Massachusetts Medical School, Gregory Cox, PhD, The Jackson Laboratory, Scot Wolfe, PhD, University of Massachusetts Medical School, Natalie Rohan, Nationwide Children's Hospital, Kevin Flanigan, MD, Nationwide Children's Hospital

Limb girdle muscular dystrophy R7 (LGMDR7 or LGMD2G) is a rare autosomal recessive muscular dystrophy caused by mutations in the gene encoding the Z-disc protein, known as telethonin or TCAP, that affects both males and females worldwide. The absence of TCAP function leads to progressive proximal limb weakness, muscle atrophy, calf hypertrophy and cardiomyopathy. We developed rAAV-mediated TCAP constructs, the expression of which results in amelioration of telethoninopathy phenotype and prevents the disease progression. Humanized TCAPKI-null (hTCAPKI) mice were systemically injected with rAAV.TCAP vectors at 6-7 weeks of age (n=3-4 mice per group), and animals were euthanized 4 weeks p.i. for gene transcription and protein analysis by RT-PCR, western blot (WB), immunofluorescence (IF). RT-PCR analysis of skeletal muscles showed the presence of both mouse and human TCAP transcript in rAAV-treated mice. WB data confirmed the restoration of TCAP expression in rAAV-treated mice showing up to 350% protein in triceps. IF staining revealed a properly co-localized TCAP protein in TCAP-Titin complex in Z-discs of sarcomeres in the skeletal muscle of rAAV-treated mice. These results suggest that rAAV-mediated TCAP replacement is a potential therapy for LGMDR7 (LGMD2G).