ENDOGENOUS OCT4 ACTIVATION VIA CRISPRA ENGINEERED VIRUS-LIKE PARTICLES IMPROVES MOTOR FUNCTION IN HUNTINGTON’S DISEASE

Huntington’s disease (HD) is a neurodegenerative disorder with mutant huntingtin (mHTT) aggregation, degeneration of striatal medium spiny neurons (MSNs), and progressive motor dysfunction. The subventricular zone (SVZ) harbors neural stem/progenitor cells with regenerative potential, these programs are constrained in HD.
We tested whether engineered virus-like particles delivering CRISPR activation (CRISPRa-eVLP) to the endogenous Oct4 locus sustained benefit over transient exogenous Oct4 protein delivery (Oct4-eVLP) in R6/2 mice. R6/2 mice received bilateral intraventricular at 4 weeks of age. Motor performance was tracked weekly by rotarod; grip strength, open field, and hindlimb clasping were assessed pre- and 8 weeks post-treatment, with SVZ and striatal analysis at 4/8 weeks post-treatment.
Significant group×time interactions in rotarod indicated CRISPRa-eVLP improved motor trajectories; open-field distance and grip increased, clasping decreased. Unlike Oct4-eVLP, which induced transient OCT4 protein exposure, CRISPRa-eVLP showed endogenous Oct4 activation and engagement of the Oct4–Sox2–Nanog transcriptional network, consistent with maintenance of progenitor-associated programs rather than indiscriminate proliferation. In the SVZ, changes in progenitor-associated marker (Nestin) together with BrdU co-labeling supported neurogenic cell birth and lineage progression. In the striatum, CRISPRa-eVLP was associated with greater DARPP-32⁺ MSN preservation and higher GAD1 and BDNF expression. In parallel, mHTT⁺ inclsuions and reactive astrogliosis (GFAP) were reduced, with lower A1- and higher A2-like astrocyte markers, consistent with attenuation of the pathological milieu.
Overall, CRISPRa-eVLP supports sustained endogenous gene regulation associated with reduced glial reactivity, enhanced neurotrophic support, and delayed motor dysfunction, highlighting transient, non-viral endogenous transcriptional control as a strategy for HD.