RNA silencing of genes involved in Alzheimer's disease enhances mitochondrial function and synaptic activity.
An age-dependent increase in mRNA levels of the amyloid precursor protein (APP), the microtubule-associated protein Tau, and voltage-dependent anion channel 1 (VDAC1) genes are reported to be toxic to neurons affected by Alzheimer's disease (AD). However, the underlying toxic nature of these genes is not completely understood. The purpose of our study was to determine the effects of RNA silencing of APP, Tau, and VDAC1 genes in AD pathogenesis. Using human neuroblastoma (SHSY5Y) cells, we first silenced RNA for APP, Tau, and VDAC1 genes, and then performed real-time RT-PCR analysis to measure mRNA levels of 34 genes that are involved in AD pathogenesis. Using biochemical assays, we also assessed mitochondrial function by measuring levels of H2O2 production, lipid peroxidation, cytochrome c oxidase activity, ATP production, and GTPase enzymatic activity. We found that increased mRNA expression of synaptic function and mitochondrial fission genes, and reduced levels of mitochondrial fusion genes in RNA silenced the SHSY5Y cells for APP, Tau and VDAC1 genes relative to the control SHSY5Y cells. In addition, RNA-silenced APP, Tau, and VDAC1 genes in SHSY5Y cells showed reduced levels of H2O2 production, lipid peroxidation, fission-linked GTPase activity, and increased cytochrome oxidase activity and ATP production. These findings suggest that a reduction of human APP, Tau, and VDAC1 may enhance synaptic activity, may improve mitochondrial maintenance and function, and may protect against toxicities of AD-related genes. Thus, these findings also suggest that the reduction of APP, Tau, and VDAC1 mRNA expressions may have therapeutic value for patients with AD.
Neurogenetics Laboratory, Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, 505 NW 185th Avenue, Beaverton, OR 97006, USA.
Maria
M
Manczak
P Hemachandra
PH
Reddy
D000255:Adenosine Triphosphate / Q000378:metabolism; D000544:Alzheimer Disease / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D016564:Amyloid beta-Protein Precursor / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western; D045222:Electron Transport Chain Complex Proteins / Q000235:genetics / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000235:genetics / Q000378:metabolism; D005609:Free Radicals / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000235:genetics / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D015227:Lipid Peroxidation; D008928:Mitochondria / Q000378:metabolism* / Q000473:pathology; D009447:Neuroblastoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D010766:Phosphorylation; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013569:Synapses / Q000378:metabolism* / Q000473:pathology; D014407:Tumor Cells, Cultured; D050995:Voltage-Dependent Anion Channel 1 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D016875:tau Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
C545487:APP protein, human; D016564:Amyloid beta-Protein Precursor; D045222:Electron Transport Chain Complex Proteins; D005609:Free Radicals; C054369:MAPT protein, human; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C494762:VDAC1 protein, human; D016875:tau Proteins; D000255:Adenosine Triphosphate; D006861:Hydrogen Peroxide; D050995:Voltage-Dependent Anion Channel 1; D003576:Electron Transport Complex IV; D020558:GTP Phosphohydrolases
Amyloid precursor protein; Human neuroblastoma cell; Immunoblotting analysis; RNA silencing; Tau; Voltage-dependent anion channel