PT - JOURNAL ARTICLE AU - Xinglong Wang AU - Bo Su AU - Hyoung-gon Lee AU - Xinyi Li AU - George Perry AU - Mark A. Smith AU - Xiongwei Zhu TI - Impaired Balance of Mitochondrial Fission and Fusion in Alzheimer's Disease AID - 10.1523/JNEUROSCI.1357-09.2009 DP - 2009 Jul 15 TA - The Journal of Neuroscience PG - 9090--9103 VI - 29 IP - 28 4099 - http://www.jneurosci.org/content/29/28/9090.short 4100 - http://www.jneurosci.org/content/29/28/9090.full SO - J. Neurosci.2009 Jul 15; 29 AB - Mitochondrial dysfunction is a prominent feature of Alzheimer's disease (AD) neurons. In this study, we explored the involvement of an abnormal mitochondrial dynamics by investigating the changes in the expression of mitochondrial fission and fusion proteins in AD brain and the potential cause and consequence of these changes in neuronal cells. We found that mitochondria were redistributed away from axons in the pyramidal neurons of AD brain. Immunoblot analysis revealed that levels of DLP1 (also referred to as Drp1), OPA1, Mfn1, and Mfn2 were significantly reduced whereas levels of Fis1 were significantly increased in AD. Despite their differential effects on mitochondrial morphology, manipulations of these mitochondrial fission and fusion proteins in neuronal cells to mimic their expressional changes in AD caused a similar abnormal mitochondrial distribution pattern, such that mitochondrial density was reduced in the cell periphery of M17 cells or neuronal process of primary neurons and correlated with reduced spine density in the neurite. Interestingly, oligomeric amyloid-β-derived diffusible ligands (ADDLs) caused mitochondrial fragmentation and reduced mitochondrial density in neuronal processes. More importantly, ADDL-induced synaptic change (i.e., loss of dendritic spine and postsynaptic density protein 95 puncta) correlated with abnormal mitochondrial distribution. DLP1 overexpression, likely through repopulation of neuronal processes with mitochondria, prevented ADDL-induced synaptic loss, suggesting that abnormal mitochondrial dynamics plays an important role in ADDL-induced synaptic abnormalities. Based on these findings, we suggest that an altered balance in mitochondrial fission and fusion is likely an important mechanism leading to mitochondrial and neuronal dysfunction in AD brain.