Duchenne muscular dystrophy (DMD) is an X-linked myopathy caused by mutations or deletions in the dystrophin gene. DMD is a common form of muscular dystrophy, affecting about 1 in every 5000 boys. DMD is a severe disease, causing progressive muscle wasting that leads to loss of ambulation and premature death in affected individuals. Despite having understood the genetic defect in DMD for the past 20 years, no approved therapy exists that has been shown to ultimately alter disease outcome. We have pioneered the development of a novel therapy for DMD based on the overexpression of GALGT2, a gene that encodes a glycosylation enzyme that alters sugars on the skeletal muscle membrane in order to boost the expression of proteins that ameliorate disease. This approach has shown therapeutic efficacy in three different mouse models of muscular dystrophy, including the mdx mouse model for DMD, suggesting that GALGT2 gene therapy may be useful in multiple forms of the disease. GALGT2 overexpression can also protect wild type muscles from injury and may therefore have therapeutic usefulness that extends beyond neuromuscular disorders. In light of these proof of concept studies demonstrating therapeutic efficacy, we have developed gene therapy vectors for use in human clinical trials. Intra-arterial delivery to the hindlimb muscles has shown functional correction in the mdx mouse and sustained expression in the non-human primate. This work has helped move us toward our goal of performing the first GALGT2 gene therapy clinical trial for DMD. The work proposed here will, for the first time, assess the therapeutic efficacy of GALGT2 in protecting the heart muscle, a muscle that greatly affects DMD morbidity and mortality. It will also test a new generation AAV vector that allows high expression in both skeletal muscle and heart to determine if single dose vascular delivery can be used to treat the whole DMD patient. Second, it will test GALGT2 gene therapy in a severe large animal model of DMD. This addresses issues of the scalability of gene therapy to the human and more rigorously tests its therapeutic value. Third, it will describe a new pathway that regulates the expression of endogenous muscle Galgt2 gene expression, opening up new approaches to exploit this important gene for therapy development.
Duchenne muscular dystrophy is a severe, progressive, and ultimately fatal neuromuscular disorder for which there are currently no therapies that ultimately alter disease outcome. The goal of this proposal is to provide proof of concept data for treatment of patients with Duchenne muscular dystrophy with a gene therapy that can be applied in a single treatment via the blood. This approach will utilize a gene therapy with overexpression of a naturally occurring glycosyltransferase gene called GALGT2 in muscle cells. Additional work will focus on understanding the natural control of muscle GALGT2 expression, with the goal of learning how to increase the muscle's natural production of this therapeutic gene.
|Camboni, Marybeth; Wang, Chiou-Miin; Miranda, Carlos et al. (2014) Active and passive immunization strategies based on the SDPM1 peptide demonstrate pre-clinical efficacy in the APPswePSEN1dE9 mouse model for Alzheimer's disease. Neurobiol Dis 62:31-43|
|Chicoine, Louis G; Rodino-Klapac, Louise R; Shao, Guohong et al. (2014) Vascular delivery of rAAVrh74.MCK.GALGT2 to the gastrocnemius muscle of the rhesus macaque stimulates the expression of dystrophin and laminin *2 surrogates. Mol Ther 22:713-24|
|Camboni, Marybeth; Hammond, Sue; Martin, Laura T et al. (2012) Induction of a regenerative microenvironment in skeletal muscle is sufficient to induce embryonal rhabdomyosarcoma in p53-deficient mice. J Pathol 226:40-9|
|Singhal, Neha; Martin, Paul T (2011) Role of extracellular matrix proteins and their receptors in the development of the vertebrate neuromuscular junction. Dev Neurobiol 71:982-1005|
|Wang, Chiou-Miin; Devries, Sarah; Camboni, Marybeth et al. (2010) Immunization with the SDPM1 peptide lowers amyloid plaque burden and improves cognitive function in the APPswePSEN1(A246E) transgenic mouse model of Alzheimer's disease. Neurobiol Dis 39:409-22|
|Chandrasekharan, Kumaran; Yoon, Jung Hae; Xu, Ying et al. (2010) A human-specific deletion in mouse Cmah increases disease severity in the mdx model of Duchenne muscular dystrophy. Sci Transl Med 2:42ra54|
|Chandrasekharan, Kumaran; Martin, Paul T (2010) Genetic defects in muscular dystrophy. Methods Enzymol 479:291-322|
|Martin, Paul T; Xu, Rui; Rodino-Klapac, Louise R et al. (2009) Overexpression of Galgt2 in skeletal muscle prevents injury resulting from eccentric contractions in both mdx and wild-type mice. Am J Physiol Cell Physiol 296:C476-88|
|Chandraskeharan, Kumaran; Martin, Paul T (2009) Embryonic overexpression of Galgt2 inhibits skeletal muscle growth via activation of myostatin signaling. Muscle Nerve 39:25-41|
|Yoon, Jung Hae; Chandrasekharan, Kumaran; Xu, Rui et al. (2009) The synaptic CT carbohydrate modulates binding and expression of extracellular matrix proteins in skeletal muscle: Partial dependence on utrophin. Mol Cell Neurosci 41:448-63|
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