Work

197. Survival, Growth, and Neurobehavioral Outcomes in a Mouse Model of Menkes Disease With CSF-Directed AAV9 and Subcutaneous Copper Histidine

Year: 2015

Type: article

Abstract: Menkes disease is a X-linked recessive neurometabolic disorder with high morbidity and mortality caused by a defective transmembrane copper transporter, ATP7A. The mottled-brindled (mo-br), a Menkes mouse model, has afforded the chance to compare clinical, biochemical, and pathological outcomes in response to specific therapeutic interventions, including rAAV5-, rAAVrh10-, and most recently, rAAV9-ATP7A viral gene therapy. The rAAV9 and rAAVrh.10 serotypes show broader neuronal tropism than rAAV5 and may gain access to the brain after systemic administration. However, the seroprevalence of maternally transmitted neutralizing antibodies against AAV in human infants from birth to 6 months suggests that peripheral administration could be suboptimal in our target population. Thus, cerebrospinal fluid (CSF)-directed rAAV9- or rAAVrh.10-ATP7A appear to represent a more suitable choice from both immunological and tissue target perspectives. In mo-br mice, we evaluated intracerebroventricular administration of rAAV9- and rAAVrh10-ATP7A, using low, medium, and high doses in affected mutants on day 2 of life, with 15 μg of clinical grade copper histidine given by subcutaneous injection between d4 and d10. Survival data from a cohort of 40 mo-br mice documented that intermediate (5.0×109 vg) and high (1.6×1010 vg) rAAV9-ATP7A doses were most effective. In correlation with the best survival benefit, CSF-directed rAAV9 + subcutaneous Cu resulted in superior murine neurobehavioral outcomes and “catch-up” growth compared to results with other serotypes, reported previously. In addition, mutant mice treated with high dose AAV9+Cu showed the highest brain viral genome copies, and markedly improved brain neurochemical and brain copper levels in comparison to untreated mutants. Brain copper measurements in combination-treated mutants (d12) were not statistically different in comparison to wild type littermates. Based on our combined data, we propose rAAV9 as a serotype of choice for first-in-human intrathecal administration in patients with Menkes disease.

Source: Molecular Therapy

DOI: 10.1016/s1525-0016(16)33802-3