Adeno-associated viral vector-mediated neurotrophin gene transfer in the injured adult rat spinal cord improves hind-limb function.
To foster axonal growth from a Schwann cell bridge into the caudal spinal cord, spinal cells caudal to the implant were transduced with adeno-associated viral (AAV) vectors encoding for brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (AAV-NT-3). Control rats received AAV vectors encoding for green fluorescent protein or saline. AAV-BDNF- and AAV-NT-3-transduced 293 human kidney cells produced and secreted BDNF or NT-3, respectively, in vitro. The secreted neurotrophins were biologically active; they both promoted outgrowth of sensory neurites in vitro. In vivo, transgene expression was observed predominantly in neurons for at least 16 weeks after injection. Compared with controls, a modest though significant improvement in hind-limb function was found in rats that received AAV-BDNF and AAV-NT-3. Retrograde tracing demonstrated that twice as many neurons with processes extending toward the Schwann cell graft were present in the second lumbar cord segment of AAV-BDNF- and AAV-NT-3-injected animals compared with controls. We found no evidence, however, for growth of regenerated axons from the Schwann cell implant into the caudal cord. Our results suggest that AAV vector-mediated overexpression of BDNF and NT-3 in the cord caudal to a Schwann cell bridge modified the local lumbar axonal circuitry, which was beneficial for locomotor function.
Blits
B
B
Graduate School for Neurosciences Amsterdam, Netherlands Institute for Brain Research, Amsterdam, The Netherlands.
Oudega
M
M
Boer
G J
GJ
Bartlett Bunge
M
M
Verhaagen
J
J
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D016380:Brain Tissue Transplantation; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics / Q000627:therapeutic use; D005260:Female; D005456:Fluorescent Dyes; D018014:Gene Transfer Techniques / Q000639:trends*; D005822:Genetic Vectors / Q000627:therapeutic use*; D006085:Graft Survival / Q000235:genetics; D020439:Growth Cones / Q000378:metabolism / Q000648:ultrastructure; D006614:Hindlimb / Q000294:innervation / Q000503:physiopathology; D009414:Nerve Growth Factors / Q000235:genetics* / Q000627:therapeutic use*; D009416:Nerve Regeneration / Q000235:genetics; D009434:Neural Pathways / Q000166:cytology / Q000254:growth & development / Q000601:surgery; D020933:Neurotrophin 3 / Q000235:genetics / Q000627:therapeutic use; D051381:Rats; D011916:Rats, Inbred F344; D011993:Recombinant Fusion Proteins; D020127:Recovery of Function / Q000235:genetics*; D012583:Schwann Cells / Q000166:cytology / Q000637:transplantation; D013116:Spinal Cord / Q000166:cytology / Q000254:growth & development / Q000601:surgery*; D013119:Spinal Cord Injuries / Q000235:genetics / Q000628:therapy*; D016896:Treatment Outcome
D019208:Brain-Derived Neurotrophic Factor; D005456:Fluorescent Dyes; D009414:Nerve Growth Factors; D020933:Neurotrophin 3; D011993:Recombinant Fusion Proteins