Abstract
After injury to the mature central nervous system (CNS), myelin-derived inhibitory ligands bind to the Nogo-66 tripartite receptor complex expressed on axonal growth cones, comprised of LINGO-1 and p75
NTR
/TROY and induce growth cone collapse through the RhoA pathway. We have also shown that amphoterin-induced gene and open reading frame-3 (AMIGO3) substitutes for LINGO-1 and can signal axon growth cone collapse. Here, we investigated the regeneration of dorsal root ganglion neuron (DRGN) axons/neurites after treatment with a short hairpin RNA (sh) AMIGO3 plasmid delivered with a non-viral
in vivo
-jetPEI vector, and the pro-survival/axogenic neurotrophin (NT) 3
in vitro
and
in vivo
. A bi
cis
tronic plasmid, containing both shAMIGO3 and NT3 knocked down >75% of AMIGO3 mRNA in cultured DRGN and significantly overexpressed NT3 production.
In vivo
, intra-DRG injection of
in vivo
-jetPEI plasmids containing shAMIGO3/
gfp
and shAMIGO3/
nt3
both knocked down AMIGO3 expression in DRGN and, in combination with NT3 overexpression, promoted DC axon regeneration, recovery of conduction of compound action potentials across the lesion site and improvements in sensory and locomotor function. These findings demonstrate that
in vivo
-jetPEI is a potential non-viral, translatable DRGN delivery vehicle
in vivo
and that suppression of AMIGO3 disinhibits the growth of axotomised DRGN enabling NT3 to stimulate the regeneration of their DC axons and enhances functional recovery.