We use cutting-edge genetic tools to fine-tune nerve repair after spinal cord injury. We’ve found that while turning off PTEN promotes nerve regrowth, it can also cause unexpected side effects—like late-onset scratching—likely due to changes in neural circuits. We employ intersectional genetics to pinpoint the specific neural circuits responsible for late-onset scratching. This targeted approach will help us uncover the underlying mechanisms of these side effects, guiding the development of therapies that promote nerve regeneration while ensuring long-term circuit stability.
Our AAV-retro studies demonstrated transduction in dorsal root ganglia (DRG) neurons and the hypothalamus, both linked to scratching responses. To see if removing PTEN in these areas causes this reaction, we use intersectional genetic methods to explore PTEN's role in late-onset scratching after spinal cord injury (SCI).
AAV-retro Cre is injected into PTEN f/f:RosatdTomato mice to allow Cre expression and PTEN deletion in corticomotor neurons (CMNs). Cre-dependent AAV-hM4D(Gi) is injected into one side of the motor cortex. The designer drug CNO (Clozapine-N-oxide) is administered to block the activity of hM4D(Gi)-expressing CMNs, which affects those projecting to the spinal cord. The effectiveness of this inhibition can be measured using immunostaining techniques like HA (hemagglutinin) staining in the cortex. This approach helps assess the role of CMNs in functional recovery when PTEN is removed.