Adeno-Associated Viral Vector-Mediated Transgene Expression Is Independent of DNA Methylation in Primate Liver and Skeletal Muscle

Recombinant adeno-associated viral (rAAV) vectors can support long-term transgene expression in quiescent tissues. Intramuscular (IM) administration of a single-stranded AAV vector (ssAAV) in the nonhuman primate (NHP) results in a peak protein level at 2–3 months, followed by a decrease over several months before reaching a steady-state. To investigate transgene expression and vector genome persistence, we previously demonstrated that rAAV vector genomes associate with histones and form a chromatin structure in NHP skeletal muscle more than one year after injection. In the mammalian nucleus, chromatin remodeling via epigenetic modifications plays key role in transcriptional regulation. Among those, CpG hyper-methylation of promoters is a known hallmark of gene silencing. To assess the involvement of DNA methylation on the transgene expression, we injected NHP via the IM or the intravenous (IV) route with a recombinant ssAAV2/1 vector. The expression cassette contains the transgene under the transcriptional control of the constitutive Rous Sarcoma Virus promoter (RSVp). Total DNA isolated from NHP muscle and liver biopsies from 1 to 37 months post-injection was treated with sodium bisulfite and subsequently analyzed by pyrosequencing. No significant CpG methylation of the RSVp was found in rAAV virions or in vector DNA isolated from NHP transduced tissues. Direct de novo DNA methylation appears not to be involved in repressing transgene expression in NHP after gene transfer mediated by ssAAV vectors. The study presented here examines host/vector interactions and the impact on transgene expression in a clinically relevant model

rAAV9-mediated gene transfer in the spinal cord of a feline model of motor neuron degeneration

National audienc

rAAV9-mediated gene transfer in the spinal cord of a feline model of motor neuron degeneration

National audienc

Long-term expression of melanopsin and channelrhodopsin causes no gross alterations in the dystrophic dog retina

International audienceSeveral preclinical studies have investigated the potential of algal channelrhodopsin and human melanopsin as optogenetic tools for vision restoration. In the present study, we assessed the potentially deleterious effects of long-term expression of these optogenes on the diseased retina in a large animal model of retinal degeneration, the RPE65-deficient Briard dog model of Leber congenital amaurosis. Intravitreal injection of adeno-associated virus vectors expressing channelrhodopsin and melanopsin had no effect on retinal thickness over a 16-month period post injection. Our data support the safety of the optogenetic approach for the treatment of blindness

Long-term expression of melanopsin and channelrhodopsin causes no gross alterations in the dystrophic dog retina

International audienceSeveral preclinical studies have investigated the potential of algal channelrhodopsin and human melanopsin as optogenetic tools for vision restoration. In the present study, we assessed the potentially deleterious effects of long-term expression of these optogenes on the diseased retina in a large animal model of retinal degeneration, the RPE65-deficient Briard dog model of Leber congenital amaurosis. Intravitreal injection of adeno-associated virus vectors expressing channelrhodopsin and melanopsin had no effect on retinal thickness over a 16-month period post injection. Our data support the safety of the optogenetic approach for the treatment of blindness

Adeno-associated virus vector (AAV) microdystrophin gene therapy prolongs survival and restores muscle function in the canine model of Duchenne muscular dystrophy (DMD)

International audienceDuchenne muscular dystrophy (DMD) is an X-linked inherited muscle-wasting disease primarily affecting young boys with a prevalence of 1:5000. The disease is caused by loss-of-function mutations in the gene encoding for the Dystrophin protein and is characterised by systemic, progressive, irreversible and severe loss of muscle function. Among vector systems that allow efficient in vivo gene transfer, recombinant Adeno Associated Virus vectors (rAAV) hold great promise and result in particular in very efficient transduction of skeletal and cardiac muscles