Activated CREB is sufficient to overcome inhibitors in myelin and promote spinal axon regeneration in vivo.
Inhibitors in myelin play a major role in preventing spontaneous axonal regeneration after CNS injury. Elevation of cAMP overcomes this inhibition, in a transcription-dependent manner, through the upregulation of Arginase I (Arg I) and increased synthesis of polyamines. Here, we show that the cAMP effect requires activation of the transcription factor cAMP response element binding protein (CREB) to overcome myelin inhibitors; a dominant-negative CREB abolishes the effect, and neurons expressing a constitutively active form of CREB are not inhibited. Activation of CREB is also required for cAMP to upregulate Arg I, and the ability of constitutively active CREB to overcome inhibition is blocked by an inhibitor of polyamine synthesis. Finally, expression of constitutively active CREB in DRG neurons is sufficient to promote regeneration of subsequently lesioned dorsal column axons. These results indicate that CREB plays a central role in overcoming myelin inhibitors and so encourages regeneration in vivo.
Gao
Ying
Y
Biology Department, Hunter College, City University of New York, 695 Park Avenue, New York, NY 10021, USA.
Deng
Kangwen
K
Hou
Jianwei
J
Bryson
J Barney
JB
Barco
Angel
A
Nikulina
Elena
E
Spencer
Tim
T
Mellado
Wilfredo
W
Kandel
Eric R
ER
Filbin
Marie T
MT
D000818:Animals; D001119:Arginase / Q000378:metabolism; D001369:Axons / Q000378:metabolism* / Q000473:pathology; D015153:Blotting, Western; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism; D002531:Cerebellum / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D005727:Ganglia, Spinal / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009186:Myelin Sheath / Q000378:metabolism*; D018992:Myelin-Associated Glycoprotein / Q000378:metabolism; D009416:Nerve Regeneration / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans
D019208:Brain-Derived Neurotrophic Factor; D017362:Cyclic AMP Response Element-Binding Protein; D018992:Myelin-Associated Glycoprotein; D000242:Cyclic AMP; D001119:Arginase