title: Rho kinase inhibition enhances axonal regeneration in the injured CNS.
abstract: Myelin-associated inhibitors limit axonal regeneration in the injured brain and spinal cord. A common target of many neurite outgrowth inhibitors is the Rho family of small GTPases. Activation of Rho and a downstream effector of Rho, p160ROCK, inhibits neurite outgrowth. Here, we demonstrate that Rho is directly activated by the myelin-associated inhibitor Nogo-66. Using a binding assay to measure Rho activity, we detected increased levels of GTP Rho in PC12 and dorsal root ganglion (DRG) cell lysates after Nogo-66 stimulation. Rho activity levels were not affected by Amino-Nogo stimulation. Rho inactivation with C3 transferase promotes neurite outgrowth of chick DRG neurons in vitro, but with the delivery method used here, it fails to promote neurite outgrowth after corticospinal tract (CST) lesions in the adult rat. Inhibition of p160ROCK with Y-27632 also promotes neurite outgrowth on myelin-associated inhibitors in vitro. Furthermore, Y-27632 enhances sprouting of CST fibers in vivo and accelerates locomotor recovery after CST lesions in adult rats.
authors.affiliation: Department of Neurology and Section of Neurobiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
authors.forename: Alyson E
authors.initials: AE
authors.lastname: Fournier
authors.forename: Bayan T
authors.initials: BT
authors.lastname: Takizawa
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Strittmatter
mesh_terms: D036002:ADP Ribose Transferases / Q000494:pharmacology; D000577:Amides / Q000494:pharmacology; D000818:Animals; D001369:Axons / Q000502:physiology*; D001905:Botulinum Toxins / Q000494:pharmacology; D002478:Cells, Cultured; D002642:Chick Embryo; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005727:Ganglia, Spinal / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D047908:Intracellular Signaling Peptides and Proteins; D009043:Motor Activity; D009185:Myelin Proteins / Q000494:pharmacology; D009416:Nerve Regeneration; D016501:Neurites / Q000502:physiology* / Q000648:ultrastructure; D000070798:Nogo Proteins; D016716:PC12 Cells; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors*; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013119:Spinal Cord Injuries / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D020741:rho GTP-Binding Proteins / Q000378:metabolism; D054460:rho-Associated Kinases
chemical_list: D000577:Amides; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D009185:Myelin Proteins; D000070798:Nogo Proteins; D011725:Pyridines; C000603197:Rtn4 protein, rat; C108830:Y 27632; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D001905:Botulinum Toxins; D020741:rho GTP-Binding Proteins