Mitochondrial Dysfunction and Apoptosis Related Gene Expression in A beta(25-35)-Treated Human Neuroblastoma Cell Line, SK-N-SH

ABSTRACT

BACKGROUND: Mitochondrial dysfunction plays an important role in Abeta-induced neuronal toxicity in Alzheimer's disease (AD). We measured the membrane potentials of mitochondria (delta psim) and assessed the genetic expressions of A beta(25-35)-induced neurotoxicity in the human neuroblastoma cell line, SK-N-SH cell. METHODS: SK-N-SH cells were incubated with a single dose of 25 micrometer A beta(25-35) for 0-24 hours, and kinetic study was done. delta psim was measured by flow cytometry. Messenger RNA expressions of cytochrome c oxidase (COX), cytochrome c, succinate dehydrogenase (SDH), amyloid-beta alcohol dehydrogenase (ABAD), caspase 9, and Bcl-2 were measured by quantitative real-time reverse transcriptase polymerase chain reaction (real-time RT-PCR). Cell death rate was measured by MTT reduction assay. RESULTS: delta psim was reduced at 24 hours. mRNA expression for COX gradually decreased by about 29% (p<0.05) while-expressions for cytochrome c, SDH, ABAD, and caspase 9 increased (p<0.05) progressively during the 24-hour time period. Bcl-2 expression decreased (p<0.05) gradually; and apoptotic cell death rate was about 24% (p<0.01) by 24 hours. CONCLUSION: Extracellular administration of A beta(25-35) contributes directly to mitochondrial dysfunction in SK-N-SH cells with the enzymatic impairment of the tricarboxylic acid cycle and electron transport chain, and eventually leading to apoptotic cell death.