Functional Rescue of the Sarcoglycan Complex in the BIO 14.6 Hamster Using δ-Sarcoglycan Gene Transfer

Abstract

Four types of limb-girdle muscular dystrophy (LGMD) are known to be caused by mutations in distinct sarcoglycan genes. The BIO 14.6 hamster is a model for sarcoglycan-deficient LGMD with a deletion in the delta-sarcoglycan (delta-SG) gene. We investigated the function of the sarcoglycan complex and the feasibility of sarcoglycan gene transfer for LGMD using a recombinant delta-SG adenovirus in the BIO 14.6 hamster. We demonstrate extensive long-term expression of delta-sarcoglycan and rescue of the entire sarcoglycan complex, as well as restored stable association of alpha-dystroglycan with the sarcolemma. Importantly, muscle fibers expressing delta-sarcoglycan lack morphological markers of muscular dystrophy and exhibit restored plasma membrane integrity. In summary, the sarcoglycan complex is requisite for the maintenance of sarcolemmal integrity, and primary mutations in individual sarcoglycan components can be corrected in vivo.

Early adenovirus-mediated gene transfer effectively prevents muscular dystrophy in alpha-sarcoglycan-deficient mice

“…21 Twelve micrograms of the proteins were resolved under reducing conditions by 3-15% SDS-PAGE and transferred to nitrocellulose membranes (Immobilon-NC, Millipore Corporation, Bedford, MA, USA).…”

“…24 Just as with ␦-SG, ␣-SG gene transfer restores the expression of the other sarcoglycan proteins at the sarcolemma of transduced fibers. [21][22][23][24] In this study, we present extensive data supporting the feasibility of an ␣-SG gene transfer approach to prevent the dystrophic process in Sgca-null mice. Direct intramuscular injection of a first-generation adenoviral vector (Ad5RSV-SGCA) into the skeletal muscle of Sgca-null mice resulted not only in a high efficiency of gene transfer, but also in a robust level of expression of ␣-SG at the sarcolemma that was sustained for at least 31 weeks.…”

“…Both approaches have proven successful in delivering ␦-SG to the skeletal muscle of a naturally occurring model for LGMD 2F, the BIO 14.6 cardiomyopathic hamster. [21][22][23] In addition, we recently reported preliminary data on adenovirus-mediated delivery of ␣-SG to the skeletal muscle of mice lacking this protein and displaying a progressive muscular dystrophy closely mimicking the human LGMD 2D pathology. 24 Just as with ␦-SG, ␣-SG gene transfer restores the expression of the other sarcoglycan proteins at the sarcolemma of transduced fibers.…”

Efficient and long-term intracardiac gene transfer in δ-sarcoglycan-deficiency hamster by adeno-associated virus-2 vectors

“…As a result of the resemblance to human patients, the Bio14.6 hamster provides an excellent animal model of gene therapy for both skeletal and cardiac deficiencies. Successful gene therapy studies on skeletal muscle in Bio14.6 hamsters have been achieved using both Ad vector 29 and AAV vectors carrying d-sarcoglycan gene, 14,15,18 which restored the missing sarcoglycan complex on the muscle cell membrane, improved both muscle histopathology and myofiber membrane integrity and, more importantly, recovered the muscle contractile force deficits. 15 In addition, direct local injection of an AAV vector carrying d-sarcoglycan gene into the myocardium of Bio14.6 hamster has been recently reported.…”

Gene transfer establishes primacy of striated vs. smooth muscle sarcoglycan complex in limb-girdle muscular dystrophy

“…The ␤-and ␦-SG constructs were then incorporated into an adenovirus vector through standard methods of homologous recombination with Ad5 backbone dl309 by the University of Iowa Gene Transfer Vector Core. Firstgeneration recombinant viruses were purified as described (12,14). Adenoviral Vector Administration.…”