TY - JOUR

T1 - A role for mixed lineage kinases in granule cell apoptosis induced by cytoskeletal disruption.

AU - Müller, Georg Johannes

AU - Geist, Marie Aavang

AU - Veng, Lone Merete

AU - Willesen, Mette Georgi

AU - Johansen, Flemming Fryd

AU - Leist, Marcel

AU - Vaudano, Elisabetta

N1 - Keywords: Animals; Animals, Newborn; Apoptosis; Blotting, Western; Carbazoles; Caspase 3; Caspases; Cell Count; Cells, Cultured; Cerebellum; Colchicine; Cytoskeleton; Dose-Response Relationship, Drug; Drug Interactions; Enzyme Activation; Enzyme Inhibitors; Gene Expression Regulation; Immunohistochemistry; Indoles; JNK Mitogen-Activated Protein Kinases; MAP Kinase Kinase Kinases; Male; Mice; Mice, Inbred BALB C; Neurons; Proto-Oncogene Proteins c-jun; Rats; Rats, Wistar; Signal Transduction; Tetrazolium Salts; Thiazoles

PY - 2006

Y1 - 2006

N2 - Microtubule disruption by colchicine induces apoptosis in selected neuronal populations. However, little is known about the upstream death signalling events mediating the neurotoxicity. We investigated first whether colchicine-induced granule cell apoptosis activates the c-Jun N-terminal kinase (JNK) pathway. Cultured murine cerebellar granule cells were exposed to 1 microm colchicine for 24 h. Activation of the JNK pathway was detected by western blotting as well as immunocytochemistry using antibodies against phospho-c-Jun (p-c-Jun). Next, adult male rats were injected intracerebroventricularly with colchicine (10 microg), and JNK pathway activation in dentate granule cells (DGCs) was detected by antibodies against p-c-Jun. The second part of the study tested the involvement of mixed lineage kinases (MLK) as upstream activators of the JNK pathway in colchicine toxicity, using CEP-1347, a potent MLK inhibitor. In vitro, significant inhibition of the JNK pathway, activated by colchicine, was achieved by 100-300 nm CEP-1347, which blocked both activation of cell death proteases and apoptosis. Moreover, CEP-1347 markedly delayed neurite fragmentation and cell degeneration. In vivo, CEP-1347 (1 mg/kg) significantly prevented p-c-jun increase following injection of colchicine, and enhanced survival of DGCs. We conclude that colchicine-induced neuronal apoptosis involves the JNK/MLK pathway, and that protection of granule cells can be achieved by MLK inhibition.

AB - Microtubule disruption by colchicine induces apoptosis in selected neuronal populations. However, little is known about the upstream death signalling events mediating the neurotoxicity. We investigated first whether colchicine-induced granule cell apoptosis activates the c-Jun N-terminal kinase (JNK) pathway. Cultured murine cerebellar granule cells were exposed to 1 microm colchicine for 24 h. Activation of the JNK pathway was detected by western blotting as well as immunocytochemistry using antibodies against phospho-c-Jun (p-c-Jun). Next, adult male rats were injected intracerebroventricularly with colchicine (10 microg), and JNK pathway activation in dentate granule cells (DGCs) was detected by antibodies against p-c-Jun. The second part of the study tested the involvement of mixed lineage kinases (MLK) as upstream activators of the JNK pathway in colchicine toxicity, using CEP-1347, a potent MLK inhibitor. In vitro, significant inhibition of the JNK pathway, activated by colchicine, was achieved by 100-300 nm CEP-1347, which blocked both activation of cell death proteases and apoptosis. Moreover, CEP-1347 markedly delayed neurite fragmentation and cell degeneration. In vivo, CEP-1347 (1 mg/kg) significantly prevented p-c-jun increase following injection of colchicine, and enhanced survival of DGCs. We conclude that colchicine-induced neuronal apoptosis involves the JNK/MLK pathway, and that protection of granule cells can be achieved by MLK inhibition.

U2 - 10.1111/j.1471-4159.2005.03590.x

DO - 10.1111/j.1471-4159.2005.03590.x

M3 - Journal article

C2 - 16478524

VL - 96

SP - 1242

EP - 1252

JO - Journal of Neurochemistry

JF - Journal of Neurochemistry

SN - 0022-3042

IS - 5

ER -