Harnessing rAAV-retro for gene manipulations in multiple pathways that are interrupted after spinal cord injury

This paper examines the potential of rAAV2-retro for delivering gene-modifying cargoes to the original cells of various pathways disrupted by spinal cord injury (SCI). It summarizes previous studies and new experiments. rAAV-retro demonstrates effective long-distance retrograde transport from pre-terminal axons and synapses to neuronal bodies. While earlier AAV-based modifications targeted single pathways, rAAV-retro can simultaneously transduce multiple spinal pathways with single spinal cord injections. Initial studies used RosatdTomato and double transgenic PTENf/f; RosatdTomato mice, where rAAV-retro/Cre transfection deleted PTEN and activated tdT expression in the same neurons. Injections into cervical, thoracic, and lumbar spinal cord achieved selective retrograde transduction in specific cortical motoneurons and subcortical region neurons associated with different spinal pathways, confirming minimal retrograde transduction in axons traveling to lower levels. We also demonstrate the feasibility of using rAAV-retro expressing shRNA against PTEN with a GFP reporter to knock down PTEN in multiple neuron populations across species. Limitations of current rAAV-retros are discussed. Overall, our findings support the potential of rAAV-retro for gene modifications in SCI.