title: Suppression of extensive neurofilament phosphorylation rescues α-Internexin/peripherin-overexpressing PC12 cells from neuronal cell death.
abstract: Intermediate filament (IF) overproduction induces abnormal accumulation of neuronal IF, which is a pathological indicator of some neurodegenerative disorders. In our study, α-Internexin- and peripherin-overexpressing PC12 cells (pINT-EGFP and pEGFP-peripherin) were used as models to study neuropathological pathways responsible for neurodegenerative diseases. Microarray data revealed that Cdk5-related genes were downregulated and Cdk5 regulatory subunit-associated protein 3 (GSK-3α and GSK-3β) were upregulated in pINT-EGFP cells. Increased expression of phosphorylated neurofilament and aberrant activation of Cdk5 and GSK-3β were detected in both pEGFP-peripherin and pINT-EGFP cells by Western blotting. In addition, pharmacological approaches to retaining viability of pINT-EGFP and pEGFP-peripherin cells were examined. Treatment with Cdk5 inhibitor and GSK-3β inhibitor significantly suppressed neuronal death. Dynamic changes of disaggregation of EGFP-peripherin and decrease in green fluorescence intensity were observed in pEGFP-peripherin and pINT-EGFP cells by confocal microscopy after GSK-3β inhibitor treatment. We conclude that inhibition of Cdk5 and GSK-3β suppresses neurofilament phosphorylation, slows down the accumulation of neuronal IF in the cytoplasm, and subsequently avoids damages to cell organelles. The results suggest that suppression of extensive neurofilament phosphorylation may be a potential strategy for ameliorating neuron death. The suppression of hyperphosphorylation of neuronal cytoskeletons with kinase inhibitors could be one of potential therapeutic treatments for neurodegenerative diseases.
authors.affiliation: Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, Taipei, Taiwan, Republic of China.
authors.forename: Wen-Ching
authors.initials: WC
authors.lastname: Lee
authors.forename: Daphne
authors.initials: D
authors.lastname: Kan
authors.forename: Yun-Yu
authors.initials: YY
authors.lastname: Chen
authors.forename: Shan-Kuo
authors.initials: SK
authors.lastname: Han
authors.forename: Kuo-Shyan
authors.initials: KS
authors.lastname: Lu
authors.forename: Chung-Liang
authors.initials: CL
authors.lastname: Chien
mesh_terms: D000818:Animals; D016923:Cell Death / Q000187:drug effects / Q000235:genetics; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D051360:Cyclin-Dependent Kinase 5 / Q000378:metabolism; D015870:Gene Expression; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D007211:Indoles / Q000494:pharmacology; D007381:Intermediate Filament Proteins / Q000235:genetics*; D008301:Maleimides / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000235:genetics*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics*; D016900:Neurofilament Proteins / Q000378:metabolism*; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D016716:PC12 Cells; D064531:Peripherins; D010766:Phosphorylation / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects / Q000235:genetics; D011687:Purines / Q000494:pharmacology; D051381:Rats; D000077546:Roscovitine
chemical_list: D007211:Indoles; D007381:Intermediate Filament Proteins; D008301:Maleimides; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D016900:Neurofilament Proteins; D064531:Peripherins; D011687:Purines; C417521:SB 216763; C046643:alpha-internexin; D000077546:Roscovitine; D051360:Cyclin-Dependent Kinase 5; D000071679:Glycogen Synthase Kinase 3 beta; C000605508:Gsk3b protein, rat; D038362:Glycogen Synthase Kinase 3