Extensive Transduction and Enhanced Spread of a Modified AAV2 Capsid in the Non-human Primate CNS

Abstract

The present study was designed to characterize transduction of non-human primate brain and spinal cord with a modified adeno-associated virus serotype 2, incapable of binding to the heparan sulfate proteoglycan receptor, referred to as AAV2-HBKO. AAV2-HBKO was infused into the thalamus, intracerebroventricularly or via a combination of both intracerebroventricular and thalamic delivery. Thalamic injection of this modified vector encoding GFP resulted in widespread CNS transduction that included neurons in deep cortical layers, deep cerebellar nuclei, several subcortical regions, and motor neuron transduction in the spinal cord indicative of robust bidirectional axonal transport. Intracerebroventricular delivery similarly resulted in widespread cortical transduction, with one striking distinction that oligodendrocytes within superficial layers of the cortex were the primary cell type transduced. Robust motor neuron transduction was also observed in all levels of the spinal cord. The combination of thalamic and intracerebroventricular delivery resulted in transduction of oligodendrocytes in superficial cortical layers and neurons in deeper cortical layers. Several subcortical regions were also transduced. Our data demonstrate that AAV2-HBKO is a powerful vector for the potential treatment of a wide number of neurological disorders, and highlight that delivery route can significantly impact cellular tropism and pattern of CNS transduction.

Intra-striatal AAV2.retro administration leads to extensive retrograde transport in the rhesus macaque brain: implications for disease modeling and therapeutic development

“…Together, these two studies illustrate the feasibility of using novel, designer AAV serotypes with a high propensity for axonal transport to distribute genetic cargo throughout brain circuits by targeting specific structures with a high degree of connectivity in the CNS, such as the thalamus and the striatum. For example, in the current study we demonstrated that AAV2.retro efficiently transduces cognitive, sensorimotor, and limbic cortico-basal ganglia circuitry via intra-striatal delivery, and the work by Naidoo and colleagues with AAV-HBKO demonstrated biodistribution throughout a different network of prefrontal, motor, temporal, and subcortical regions following thalamic infusion 48,49 . Taken together, these studies illustrate how widespread transduction patterns can be achieved even in the large NHP brain by selecting a serotype with high propensity for transport and by selectively choosing the site of injection to target specific populations of neuronal afferents/efferents depending on the network of interest or the specific disease being targeted.…”

“…Naidoo and colleagues demonstrated that intra-thalamic delivery of AAV-HBKO expressing eGFP resulted in robust anterograde transport to deep layers of many cortical regions with thalamic efferents including the ACC, DPFC, VPFC, DPMC, VPMC, PMC, SSC, and ITC. The authors also report evidence of moderate retrograde transport to some subcortical structures and to regions of the brain stem and spinal cord 48 .…”

“…It is noteworthy that other AAV serotypes exhibit low to moderate levels of retrograde transport, such as AAV1 45,46 and AAV6 47 , but by comparison the degree of retrograde transport is greatly enhanced in AAV2.retro 31 . There are, however, other AAV capsid variants that have been recently reported to also transport robustly in the NHP brain, such as AAV-HBKO 48 . Naidoo and colleagues demonstrated that intra-thalamic delivery of AAV-HBKO expressing eGFP resulted in robust anterograde transport to deep layers of many cortical regions with thalamic efferents including the ACC, DPFC, VPFC, DPMC, VPMC, PMC, SSC, and ITC.…”

Intra-striatal AAV2.retro administration leads to extensive retrograde transport in the rhesus macaque brain: implications for disease modeling and therapeutic development

“…Naidoo and colleagues demonstrated that intra-thalamic delivery of AAV-HBKO expressing eGFP resulted in robust anterograde transport to deep layers of many cortical regions with thalamic efferents including the ACC, DPFC, VPFC, DPMC, VPMC, PMC, SSC, and ITC. The authors also report evidence of moderate retrograde transport to some subcortical structures and to regions of the brain stem and spinal cord 49 . This contrasts with the pattern of nearly exclusive retrograde transport seen here with AAV2.…”

“…retro 32 . There are, however, other AAV capsid variants that have been recently reported to also transport robustly in the NHP brain, such as AAV-HBKO 49 . Naidoo and colleagues demonstrated that intra-thalamic delivery of AAV-HBKO expressing eGFP resulted in robust anterograde transport to deep layers of many cortical regions with thalamic efferents including the ACC, DPFC, VPFC, DPMC, VPMC, PMC, SSC, and ITC.…”