title: Caspase-Cleaved Tau Impairs Mitochondrial Dynamics in Alzheimer's Disease.
abstract: Alzheimer's disease (AD) is characterized by the presence of aggregates of tau protein. Tau truncated by caspase-3 (D421) or tau hyperphosphorylated at Ser396/S404 might play a role in the pathogenesis of AD. Mitochondria are dynamic organelles that modify their size and function through mitochondrial dynamics. Recent studies have shown that alterations of mitochondrial dynamics affect synaptic communication. Therefore, we studied the effects of pathological forms of tau on the regulation of mitochondrial dynamics. We used primary cortical neurons from tau(-/-) knockout mice and immortalized cortical neurons (CN1.4) that were transfected with plasmids containing green fluorescent protein (GFP) or GFP with different tau forms: full-length (GFP-T4), truncated (GFP-T4C3), pseudophosphorylated (GFP-T42EC), or both truncated and pseudophosphorylated modifications of tau (GFP-T4C3-2EC). Cells expressing truncated tau showed fragmented mitochondria compared to cells that expressed full-length tau. These findings were corroborated using primary neurons from tau(-/-) knockout mice that expressed the truncated and both truncated and pseudophosphorylated forms of tau. Interestingly, mitochondrial fragmentation was accompanied by a significant reduction in levels of optic atrophy protein 1 (Opa1) in cells expressing the truncated form of tau. In addition, treatment with low concentrations of amyloid-beta (Aβ) significantly reduced mitochondrial membrane potential, cell viability, and mitochondrial length in cortical cells and primary neurons from tau(-/-) mice that express truncated tau. These results indicate that the presence of tau pathology impairs mitochondrial dynamics by reducing Opa1 levels, an event that could lead to mitochondrial impairment observed in AD.
authors.affiliation: Laboratory of Neurodegenerative Diseases, Centro de Investigación Biomédica, Universidad Autónoma de Chile, El Llano Subercaseaux 2801 5to Piso, San Miguel, 8910000, Santiago, Chile.
authors.forename: María José
authors.initials: MJ
authors.lastname: Pérez
authors.affiliation: Laboratory of Neurodegenerative Diseases, Centro de Investigación Biomédica, Universidad Autónoma de Chile, El Llano Subercaseaux 2801 5to Piso, San Miguel, 8910000, Santiago, Chile.
authors.forename: Katiana
authors.initials: K
authors.lastname: Vergara-Pulgar
authors.affiliation: Laboratory of Neurodegenerative Diseases, Centro de Investigación Biomédica, Universidad Autónoma de Chile, El Llano Subercaseaux 2801 5to Piso, San Miguel, 8910000, Santiago, Chile.
authors.forename: Claudia
authors.initials: C
authors.lastname: Jara
authors.affiliation: Laboratory of Neurodegenerative Diseases, Centro de Investigación Biomédica, Universidad Autónoma de Chile, El Llano Subercaseaux 2801 5to Piso, San Miguel, 8910000, Santiago, Chile.
authors.forename: Fabian
authors.initials: F
authors.lastname: Cabezas-Opazo
authors.affiliation: Laboratory of Neurodegenerative Diseases, Centro de Investigación Biomédica, Universidad Autónoma de Chile, El Llano Subercaseaux 2801 5to Piso, San Miguel, 8910000, Santiago, Chile. rodrigo.quintanilla@uautonoma.cl.|Centro de Investigación y Estudio del Consumo de Alcohol en Adolescentes (CIAA), Santiago, Chile. rodrigo.quintanilla@uautonoma.cl.
authors.forename: Rodrigo A
authors.initials: RA
authors.lastname: Quintanilla
mesh_terms: D000544:Alzheimer Disease / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D008928:Mitochondria / Q000378:metabolism*; D063154:Mitochondrial Dynamics / Q000502:physiology*; D009474:Neurons / Q000378:metabolism*; D010766:Phosphorylation; D016875:tau Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D016875:tau Proteins; D049452:Green Fluorescent Proteins
keywords: Alzheimer’s disease; Mitochondria; Neurodegeneration; Opa1; Tau