Domire, J. S. | Search bioRxiv

bioRxiv2022

A novel rhesus macaque model of Huntington's disease recapitulates key neuropathological changes along with progressive motor and cognitive decline

We created a new nonhuman primate model of the genetic neurodegenerative disorder, Huntingtons disease (HD), by injecting a mixture of recombinant adeno-associated viral vectors, serotypes AAV2 and AAV2.retro, each expressing a fragment of human mutant HTT (mHTT) into the caudate and putamen of adult rhesus macaques. This novel modeling strategy results in robust expression of mutant huntingtin protein (mHTT) in the injected brain regions, as well as dozens of other cortical and subcortical brain regions that are also affected in human HD patients. We queried the disruption of cortico-basal ganglia circuitry for 20-months post-surgery using a variety of behavioral and imaging readouts. Compared to controls, mHTT-treated macaques developed progressive working memory decline and motor impairment. Multimodal imaging revealed circuit-wide white and gray matter degenerative processes in several key brain regions affected in HD. This novel model will aid in the development of disease biomarkers and therapeutic strategies for this devastating disorder.

neuroscience↗

bioRxiv2020

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

Recently, AAV2.retro, a new capsid variant capable of efficient retrograde transport in brain, was generated in mice using a directed evolution approach. However, it remains unclear to what degree transport will be recapitulated in the substantially larger and more complex nonhuman primate (NHP) brain. Here, we compared the biodistribution of AAV2.retro with its parent serotype, AAV2, in adult macaques following delivery into the caudate and putamen, brain regions which comprise the striatum. While AAV2 transduction was primarily limited to the injected brain regions, AAV2.retro transduced cells in the striatum and in dozens of cortical and subcortical regions with known striatal afferents. We then evaluated the capability of AAV2.retro to deliver disease-related gene cargo to biologically-relevant NHP brain circuits by packaging a fragment of human mutant HTT, the causative gene mutation in Huntingtons disease. Following intra-striatal delivery, pathological mHTT-positive protein aggregates were distributed widely among cognitive, motor, and limbic cortico-basal ganglia circuits. Together, these studies demonstrate strong retrograde transport of AAV2.retro in NHP brain, highlight its utility in developing novel NHP models of brain disease and suggest its potential for querying circuit function and delivering therapeutic genes in the brain, particularly where treating dysfunctional circuits, versus single brain regions, is warranted.

neuroscience↗