title: Regeneration of axons in injured spinal cord by activation of bone morphogenetic protein/Smad1 signaling pathway in adult neurons.
abstract: Axon growth potential is highest in young neurons but diminishes with age, thus becoming a significant obstacle to axonal regeneration after injury in maturity. The mechanism for the decline is incompletely understood, and no effective clinical treatment is available to rekindle innate growth capability. Here, we show that Smad1-dependent bone morphogenetic protein (BMP) signaling is developmentally regulated and governs axonal growth in dorsal root ganglion (DRG) neurons. Down-regulation of the pathway contributes to the age-related decline of the axon growth potential. Reactivating Smad1 selectively in adult DRG neurons results in sensory axon regeneration in a mouse model of spinal cord injury (SCI). Smad1 signaling can be effectively manipulated by an adeno-associated virus (AAV) vector encoding BMP4 delivered by a clinically applicable and minimally invasive technique, an approach devoid of unwanted abnormalities in mechanosensation or pain perception. Importantly, transected axons are able to regenerate even when the AAV treatment is delivered after SCI, thus mimicking a clinically relevant scenario. Together, our results identify a therapeutic target to promote axonal regeneration after SCI.
authors.affiliation: Fishberg Department of Neuroscience, Friedman Brain Institute, Mount Sinai School of Medicine, New York, NY 10029, USA.
authors.forename: Pranav
authors.initials: P
authors.lastname: Parikh
authors.forename: Yuhan
authors.initials: Y
authors.lastname: Hao
authors.forename: Mohsen
authors.initials: M
authors.lastname: Hosseinkhani
authors.forename: Shekhar B
authors.initials: SB
authors.lastname: Patil
authors.forename: George W
authors.initials: GW
authors.lastname: Huntley
authors.forename: Marc
authors.initials: M
authors.lastname: Tessier-Lavigne
authors.forename: Hongyan
authors.initials: H
authors.lastname: Zou
mesh_terms: D000818:Animals; D001369:Axons / Q000473:pathology / Q000502:physiology*; D055415:Bone Morphogenetic Protein 4 / Q000235:genetics / Q000502:physiology* / Q000627:therapeutic use; D000229:Dependovirus / Q000235:genetics; D004195:Disease Models, Animal; D005260:Female; D005727:Ganglia, Spinal / Q000473:pathology / Q000503:physiopathology; D005822:Genetic Vectors; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008959:Models, Neurological; D009416:Nerve Regeneration / Q000502:physiology*; D011994:Recombinant Proteins / Q000235:genetics / Q000627:therapeutic use; D015398:Signal Transduction; D051898:Smad1 Protein / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D013119:Spinal Cord Injuries / Q000473:pathology / Q000503:physiopathology* / Q000628:therapy*
chemical_list: C525810:Bmp4 protein, mouse; D055415:Bone Morphogenetic Protein 4; D011994:Recombinant Proteins; D051898:Smad1 Protein; C497401:Smad1 protein, mouse