| First Author | Manczak M | Year | 2016 |
| Journal | Hum Mol Genet | Volume | 25 |
| Issue | 23 | Pages | 5148-5166 |
| PubMed ID | 27677309 | Mgi Jnum | J:239247 |
| Mgi Id | MGI:5828036 | Doi | 10.1093/hmg/ddw330 |
| Citation | Manczak M, et al. (2016) Protective effects of reduced dynamin-related protein 1 against amyloid beta-induced mitochondrial dysfunction and synaptic damage in Alzheimer's disease. Hum Mol Genet 25(23):5148-5166 |
| abstractText | The purpose of our study was to understand the protective effects of reduced expression of dynamin-related protein (Drp1) against amyloid beta (Abeta) induced mitochondrial and synaptic toxicities in Alzheimer's disease (AD) progression and pathogenesis. Our recent molecular and biochemical studies revealed that impaired mitochondrial dynamics-increased mitochondrial fragmentation and decreased fusion-in neurons from autopsy brains of AD patients and from transgenic AD mice and neurons expressing Abeta, suggesting that Abeta causes mitochondrial fragmentation in AD. Further, our recent co-immunoprecipitation and immunostaining analysis revealed that the mitochondrial fission protein Drp1 interacted with Abeta, and this interaction increased as AD progressed. Based on these findings, we hypothesize that a partial deficiency of Drp1 inhibits Drp1-Abeta interactions and protects Abeta-induced mitochondrial and synaptic toxicities, and maintains mitochondrial dynamics and neuronal function in AD neurons. We crossed Drp1+/- mice with APP transgenic mice (Tg2576 line) and created double mutant (APPXDrp1+/-) mice. Using real-time RT-PCR and immunoblotting analyses, we measured mRNA expressions and protein levels of genes related to the mitochondrial dynamics, mitochondrial biogenesis and synapses from 6-month-old Drp1+/-, APP, APPXDrp1+/- and wild-type (WT) mice. Using biochemical methods, we also studied mitochondrial function and measured soluble Abeta in brain tissues from all lines of mice in our study. Decreased mRNA expressions and protein levels of Drp1 and Fis1 (fission) and CypD (matrix) genes, and increased levels of Mfn1, Mfn2 and Opa1 (fusion), Nrf1, Nrf2, PGC1alpha, TFAM (biogenesis) and synaptophysin, PSD95, synapsin 1, synaptobrevin 1, neurogranin, GAP43 and synaptopodin (synaptic) were found in 6-month-old APPXDrp1+/- mice relative to APP mice. Mitochondrial functional assays revealed that mitochondrial dysfunction is reduced in APPXDrp1+/- mice relative to APP mice, suggesting that reduced Drp1enhances mitochondrial function in AD neurons. Sandwich ELISA assay revealed that soluble Abeta levels were significantly reduced in APPXDrp1+/- mice relative to APP mice, indicating that reduced Drp1 decreases soluble Abeta production in AD progression. These findings suggest that a partial reduction of Drp1 reduces Abeta production, reduces mitochondrial dysfunction, and maintains mitochondrial dynamics, enhances mitochondrial biogenesis and synaptic activity in APP mice. These findings may have implications for the development of Drp1 based therapeutics for AD patients. |
