AAVrh.10-Mediated APOE2 Central Nervous System Gene Therapy for APOE4-Associated Alzheimer's Disease

Abstract

Alzheimer's disease (AD) is a progressive degenerative neurological disorder affecting nearly one in nine elderly people in the United States. Population studies have shown that an inheritance of the apolipoprotein E (APOE) variant APOE4 allele increases the risk of developing AD, whereas APOE2 homozygotes are protected from late-onset AD. It was hypothesized that expression of the "protective" APOE2 variant by genetic modification of the central nervous system (CNS) of APOE4 homozygotes could reverse or prevent progressive neurologic damage. To assess the CNS distribution and safety of APOE2 gene therapy for AD in a large-animal model, intraparenchymal, intracisternal, and intraventricular routes of delivery to the CNS of nonhuman primates of AAVrh.10hAPOE2-HA, an AAVrh.10 serotype coding for an HA-tagged human APOE2 cDNA sequence, were evaluated. To evaluate the route of delivery that achieves the widest extent of APOE2 expression in the CNS, the expression of APOE2 in the CNS was evaluated 2 months following vector administration for APOE2 DNA, mRNA, and protein. Finally, using conventional toxicology assays, the safety of the best route of delivery was assessed. The data demonstrated that while all three routes are capable of mediating ApoE2 expression in AD relevant regions, intracisternal delivery of AAVrh.10hAPOE2-HA safely mediated wide distribution of ApoE2 with the least invasive surgical intervention, thus providing the optimal strategy to deliver vector-mediated human APOE2 to the CNS.

Neuron‐targeted caveolin‐1 improves neuromuscular function and extends survival in SOD1 G93A mice

“…Intrathecal delivery, direct spinal cord, and brain injections have all demonstrated safety. Presently, there are several viral-mediated gene-therapy clinical trials for neurodegenerative diseases (3), and recent intracisternal AAV delivery in nonhuman primates demonstrated wide transgene expression (35). In December 2017, the Food and Drug Administration approved the first-ever AAV-mediated gene therapy for retinal dystrophy, demonstrating a monumental shift in CNS therapies.…”

Therapeutic approaches targeting Apolipoprotein E function in Alzheimer’s disease

“…This study also showed that gene delivery of APOE2 was most effective before the onset of amyloid burden, suggesting that in order to be a successful therapy the AAV would need to be injected much before the onset of symptoms in patients which poses its own challenges. Further translational studies on non-human primates revealed that intra-cisternal delivery of AAV-APOE2 led to widespread expression in the CNS which established a safe procedure for CNS delivery of biologics [166]. Because of the inherent risk in any surgical procedure inside the CNS, whether such AAV-APOE2 biologics can be directly delivered into the AD-affected areas of the human CNS needs to be cautiously determined.…”

Anti-Phospho-Tau Gene Therapy for Chronic Traumatic Encephalopathy

“…AAVrh.10CisTau coding for the anti-Tau monoclonal Cis-Tau 33,59 ; and AAVrh.10Null used as a control, identical to the other vectors but with no gene coding sequence. 41 PHF1 hybridoma cell cDNA (gift from Peter Davies, Albert Einstein College of Medicine) was amplified and synthesized in two independent reactions using primer annealing conserved regions of the constant heavy and light chains. The cDNA containing the mouse heavy chain sequence from IgG1 and the mouse Kappa light chain sequence was amplified using nested primers, cloned into a TOPO vector (Thermo Fisher Scientific, Inc., Carlsbad, CA) and sequenced.…”

“…All vectors were produced using 293T cells as described previously. [40][41][42][43]60 Briefly, the expression plasmid and the AAVrh.10 packaging-Ad helper hybrid plasmid pPAK-MArh.10 were cotransfected into 293T cells using the PEI transfection reagent (Polysciences, Warrington, PA). At 72 h post-transfection, cells were harvested and lysate prepared using five cycles of freeze/thaw.…”

“…To test this hypothesis, we used an AAVrh.10 serotype gene transfer vector because there is low anti-AAVrh.10 seroprevalence in humans, 39 AAVrh.10 mediates high expression of transgenes in neurons in experimental animal models, [40][41][42][43] and AAVrh.10 vectors have been used safely in clinical trials to deliver the therapeutic genes to the CNS of children with mucopolysaccharidosis IIIB and metachromatic leukodystrophy. 44,45 To evaluate an AAVrh.10 anti-Tau-based therapy, we developed a murine repetitive TBI model that is mechanistically unlike the age-related degenerative disease models.…”