Focused Ultrasounds as an Adeno-Associated Virus Gene Therapy-Empowering Tool in Juvenile Mice via Intracerebroventricular Administration

Systemic delivery of adeno-associated virus (AAV) vectors targeting the central nervous system has the potential to solve many neurodevelopmental disorders, yet it is made difficult by the filtering effect of the blood-brain barrier and systemic complications. To overcome this limitation, we attempted to inject a Venus-expressing, oligodendrocyte-selective AAV9 viral vector in the ventricles together with lipid microbubbles and subjected them to focused ultrasound (FUS); the resulting mechanical stimulation on the brain ventricles is able to open small, temporary gaps from which vector particles can leak and spread. Our findings indicate that FUS can increase viral vector diffusion across both the anteroposterior and left-right axes without influencing cell tropism; significant effects were found with 60 and 90 s exposure time, but no effects were observed with longer intervals. Taken together, these results highlight a new strategy for the safe and effective delivery of viral vectors and offer new perspectives for the development and application of gene therapies for central nervous system diseases.