title: Early induction of calpains in rotenone-mediated neuronal apoptosis.
abstract: Rotenone is an inhibitor of mitochondrial complex I that produces a model of Parkinson's disease (PD), where neurons undergo apoptosis by caspase-dependent and/or caspase-independent pathways. Inhibition of calpains has recently been shown to attenuate neuronal apoptosis. This study aims to establish for the first time, the time-point of calpain activation with respect to the caspase activation and the possibility of cell cycle re-entry in rotenone-mediated cell death. Immunoblot results revealed calpain activation occurred at 5, 10h prior to caspase-3 activation (at 15 h), suggesting calpain activation was an earlier cellular event compared to caspase activation in the rotenone-mediated apoptosis. In addition, an upregulation of phospho-p53 was observed at 21 h. However, no expression or upregulation of cell cycle regulatory proteins including cdc25a, cyclin-D1 and cyclin-D3 were observed, strongly suggesting that cell cycle re-entry did not occur. These findings provide new insights into the differential patterns of calpain and caspase activation that result from rotenone poisoning and which may be relevant to the therapeutic management of PD.
authors.affiliation: Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, Singapore 117597, Republic of Singapore.
authors.forename: Minghui Jessica
authors.initials: MJ
authors.lastname: Chen
authors.forename: Yann Wan
authors.initials: YW
authors.lastname: Yap
authors.forename: Meng Shyan
authors.initials: MS
authors.lastname: Choy
authors.forename: Chor Hui Vivien
authors.initials: CH
authors.lastname: Koh
authors.forename: Sze Jee
authors.initials: SJ
authors.lastname: Seet
authors.forename: Wei
authors.initials: W
authors.lastname: Duan
authors.forename: Matthew
authors.initials: M
authors.lastname: Whiteman
authors.forename: Nam Sang
authors.initials: NS
authors.lastname: Cheung
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western / Q000379:methods; D002154:Calpain / Q000096:biosynthesis*; D002352:Carrier Proteins / Q000378:metabolism; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D004305:Dose-Response Relationship, Drug; D004622:Embryo, Mammalian; D004790:Enzyme Induction / Q000187:drug effects*; D005786:Gene Expression Regulation / Q000187:drug effects; D007306:Insecticides / Q000494:pharmacology*; D051379:Mice; D008840:Microfilament Proteins / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects*; D051381:Rats; D012402:Rotenone / Q000494:pharmacology*; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D013049:Spectrin
chemical_list: D002154:Calpain; D002352:Carrier Proteins; D053148:Caspase 3; D020169:Caspases; D007306:Insecticides; D008840:Microfilament Proteins; D012402:Rotenone; D016159:Tumor Suppressor Protein p53; D013049:Spectrin; C505409:Casp3 protein, mouse; C505410:Casp3 protein, rat