Implication of cyclin-dependent kinase 5 in the neuroprotective properties of lithium.
Although numerous studies have demonstrated a neuroprotective and anti-apoptotic role of lithium in neuronal cell cultures, the precise mechanism by which this occurs, remains to be elucidated. In this study, we evaluated the lithium-mediated neuroprotection against colchicine-induced apoptosis in cultured cerebellar granule neurons. Previously, it has been demonstrated that colchicine mediates apoptosis in cerebellar granule neurons through cytoskeletal alteration and activation of an intrinsic pro-apoptotic pathway. Recently we also demonstrated a potential role of cyclin-dependent kinase 5 (cdk5) in this pathway. Here we report that colchicine induces dephosphorylation in Ser-9 and phosphorylation in Tyr-216, and thus activation, of glycogen synthase kinase-3beta in cerebellar granule neurons, and that this modification is inhibited by the presence of 5 mM lithium. However, the selective glycogen synthase kinase-3beta inhibitors SB-415286 and SB-216763 were unable to prevent colchicine-induced apoptosis in these cells, suggesting that the anti-apoptotic activity of lithium is not mediated by glycogen synthase kinase-3beta under these conditions. On the other hand, 5 mM lithium prevented the colchicine-induced increase in cdk5 expression and breakdown of cdk5/p35 to cdk5/p25. In addition, we show that up-regulation of cdk5/p25 is unrelated to inhibition of the activity of myocyte enhancer factor 2, a pro-survival transcription factor. These data suggest a previously undescribed neuroprotective mechanism of lithium associated with the modulation of cdk5/p35 or cdk5/p25 expression.
Unitat de Farmacologia i Farmacognòsia, Facultat de Farmàcia, Universitat de Barcelona, Nucli Universitari de Pedralbes, E-08028 Barcelona, Spain.
E G
EG
Jordà
E
E
Verdaguer
A M
AM
Canudas
A
A
Jiménez
S
S
Garcia de Arriba
C
C
Allgaier
M
M
Pallàs
A
A
Camins
D000627:Aminophenols / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western / Q000379:methods; D020169:Caspases / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology*; D003078:Colchicine / Q000494:pharmacology; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D051360:Cyclin-Dependent Kinase 5; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry / Q000379:methods; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D007211:Indoles / Q000494:pharmacology; D008094:Lithium / Q000008:administration & dosage*; D064326:MEF2 Transcription Factors; D008301:Maleimides / Q000494:pharmacology; D046529:Microscopy, Electron, Transmission / Q000379:methods; D018006:Myogenic Regulatory Factors; D009474:Neurons / Q000187:drug effects* / Q000648:ultrastructure; D018696:Neuroprotective Agents / Q000008:administration & dosage*; D011191:Potassium Deficiency; D051381:Rats; D017207:Rats, Sprague-Dawley; D012694:Serine / Q000378:metabolism; D013912:Threonine / Q000378:metabolism; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism
C417520:3-(3-chloro-4-hydroxyphenylamino)-4-(4-nitrophenyl)-1H-pyrrole-2,5-dione; D000627:Aminophenols; D016895:Culture Media, Serum-Free; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D007211:Indoles; D064326:MEF2 Transcription Factors; D008301:Maleimides; D018006:Myogenic Regulatory Factors; D018696:Neuroprotective Agents; C417521:SB 216763; D014157:Transcription Factors; D013912:Threonine; D012694:Serine; D008094:Lithium; D051360:Cyclin-Dependent Kinase 5; D000071679:Glycogen Synthase Kinase 3 beta; C000605508:Gsk3b protein, rat; C495907:Cdk5 protein, rat; D018844:Cyclin-Dependent Kinases; D038362:Glycogen Synthase Kinase 3; D020169:Caspases; D003078:Colchicine