Neurotrophic effects of serum- and glucocorticoid-inducible kinase on adult murine mesencephalic dopamine neurons.
Mesencephalic dopamine neurons are central to many aspects of human cognition, motivational, and motor behavior, and they are uniquely vulnerable to degenerative neurologic disorders such as Parkinson's disease. There is growing evidence that in the mature brain these neurons not only remain responsive to neurotrophic support, but are dependent on it for viability and function. Little is known of the cellular signaling pathways that mediate this support, although some evidence suggests that protein kinase Akt/PKB may play such a role. Another candidate for such a role is serum- and glucocorticoid-inducible kinase (SGK), a member of the AGC kinase family that is closely related to Akt. We have herein examined the responsiveness of adult mouse dopamine neurons in vivo to overexpression of wild-type and a constitutively active form of SGK by use of viral vector transfer in normal mice and both before and after 6-OHDA lesion. We find that SGK induces a broad spectrum of neurotrophic effects on these neurons, including induction of neuronal hypertrophy, protection from both neuron death and neurotoxin-induced retrograde axonal degeneration, and axon regeneration. Given the diverse and robust effects of SGK on these neurons, and its abundant expression in them, we suggest that SGK, like closely related Akt, may play a role in their responsiveness to neurotrophic factors and in adult maintenance. It therefore offers a novel target for therapeutic development.
Department of Neurology, Columbia University, New York, New York 10032, USA.
Xiqun
X
Chen
Patricia
P
Tagliaferro
Tatyana
T
Kareva
Olga
O
Yarygina
Nikolai
N
Kholodilov
Robert E
RE
Burke
D000818:Animals; D002452:Cell Count; D016923:Cell Death / Q000187:drug effects / Q000235:genetics; D059290:Dopaminergic Neurons / Q000187:drug effects / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology*; D005822:Genetic Vectors / Q000502:physiology; D049452:Green Fluorescent Proteins / Q000235:genetics; D017874:Immediate-Early Proteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008474:Medial Forebrain Bundle / Q000166:cytology / Q000187:drug effects; D008636:Mesencephalon / Q000166:cytology* / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009154:Mutation / Q000235:genetics; D009410:Nerve Degeneration / Q000139:chemically induced / Q000378:metabolism; D016627:Oxidopamine / Q000633:toxicity; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D018709:Statistics, Nonparametric; D013565:Sympatholytics / Q000633:toxicity; D014161:Transduction, Genetic / Q000379:methods; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics / Q000378:metabolism; D000099184:Serum-Glucocorticoid Regulated Kinases
D049452:Green Fluorescent Proteins; D017874:Immediate-Early Proteins; D016627:Oxidopamine; D010751:Phosphopyruvate Hydratase; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger; D013565:Sympatholytics; D014446:Tyrosine 3-Monooxygenase; D000099184:Serum-Glucocorticoid Regulated Kinases