Enhanced survival of the LINCL mouse following CLN2 gene transfer using the rh.10 rhesus Macaque-derived Adeno-associated virus vector

Abstract

Late infantile neuronal ceroid lipofuscinosis (LINCL) is a lysosomal storage disorder caused by mutations in the CLN2 gene and a deficiency of tripeptidyl peptidase I (TPP-I). Prior studies with adeno-associated virus (AAV) serotype 2 or 5 mediated transfer of the CLN2 complementary DNA to the central nervous system (CNS) of CLN2-/- mice cleared CNS storage granules, but provided no improvement in the phenotype or survival of this model of LINCL. In this study, AAV serotypes (AAV2, AAV5, AAV8, and AAVrh.10) were compared for the delivery of the same CLN2 expression cassette. AAVrh.10, derived from rhesus macaque, provided the highest TPP-I level and maximum spread beyond the site of injection. The AAVrh.10-based vector functioned equally well in naive rats and in rats previously immunized against human serotypes of AAV. When administered to the CNS of CLN2-/- mice, the AAVrh.10CLN2 vector provided widespread TPP-I activity comparable to that in the wild-type mice. Importantly, the AAVrh.10CLN2-treated CLN2-/- mice had significant reduction in CNS storage granules and demonstrated improvement in gait, nest-making abilities, seizures, balance beam function, and grip strength, as well as having a survival advantage.