Sustained Muscle
Expression of Dystrophin from a High-Capacity Adenoviral Vector with Systemic
Gene Transfer of T Cell Costimulatory Blockade
Molecular Therapy, 2004
Zhilong
Jiang, Gudrun Schiedner, Nico van Rooijen, Chau-Ching Liu, Stefan Kochanek, and
Paula R. Clemens - USA
Adenoviral vector (Ad)-mediated gene
delivery of normal, full-length dystrophin to skeletal muscle provides a
promising strategy for the treatment of Duchenne muscular dystrophy (DMD).
However, cellular and humoral immune responses induced by vector gene transfer
limit the application of this approach. Blockade of the costimulatory
interaction between naRve T cells and antigen-presenting cells has proven to be
a successful means to diminish immunity induced by gene transfer. In this study
we explore the potential of supplementing dystrophin gene delivery to
dystrophin-deficient Dmd mouse skeletal muscle with systemic gene delivery of
CTLA4Ig and CD40Ig molecules to effect costimulatory blockade. We found that
systemic administration of a high-capacity Ad (HC-Ad) vector carrying murine
CTLA4Ig (AdmCTLA4Ig) either alone or codelivered with an HC-Ad vector carrying
murine CD40Ig (AdmCD40Ig) provided sustained expression of recombinant
full-length murine dystrophin from an HC-Ad vector carrying the dystrophin cDNA
(AdmDys). The level of AdmDys vector genomes remained stable in animals
cotreated with systemic delivery of vectors carrying molecules to block
costimulation. In addition, muscle CD4+ and CD8+ T cell infiltrates and Th1
cytokine production by splenocytes were reduced. The production of neutralizing
antibody against Ad vector was significantly inhibited in mice receiving
systemic codelivery of both AdmCTLA4Ig and AdmCD40Ig, but not in the mice
treated with AdmCTLA4Ig alone. The results suggested that coblockade of both
CD28/B7 and CD40L/CD40 costimulatory pathways is required for effective
inhibition of the Ad vector-induced humoral immune response in Dmd mice,
whereas blockade of CD28/B7 alone by murine CTLA4Ig would be sufficient for
prolonged dystrophin expression in treated muscle.
The alteration of calcium homeostasis in adult dystrophic mdx muscle
fibers is worsened by a chronic exercise in vivo
Neurobiology of Disease, 2004
Bodvael
Fraysse, Antonella Liantonio, Michela Cetrone,Rosa Burdi, Sabata Pierno,
Antonio Frigeri, Michela Pisoni,Claudia Camerino, and Annamaria De Lucaa -
Italy
Chronic exercise in vivo aggravates
dystrophy in mdx mice. Calcium homeostasis was evaluated ex vivo by
micro-spectrofluorometry on tendon-to-tendon dissected extensor digitorum
longus (EDL) muscle fibers. Resting cytosolic calcium ([Ca2+]i) and sarcolemmal
permeability through Gd3+-sensitive mechanosensitive calcium (MsCa) channel
were significantly higher in mdx vs. wild-type fibers. The exercise further
enhanced [Ca2+]i in mdx fibers and increased sarcolemmal permeability by
activating nifedipine-sensitive leak calcium channels. The two genotypes did
not differ in caffeine sensitivity and in the excitation-calcium release (ECaR)
coupling mechanism by K+ depolarization. The exercise produced a similar
adaptation of activation curve of ECaR and of sensitivity to caffeine. However,
the inactivation of ECaR of mdx fibers did not adapt to exercise. No fiber
phenotype transition occurred in exercised muscle. We provide the first
evidence that an in vivo exercise worsens the impaired calcium homeostasis of
dystrophic fibers, supporting the role of enhanced calcium entrance in
dystrophic progression.