Tau accumulation causes mitochondrial distribution deficits in neurons in a mouse model of tauopathy and in human Alzheimer's disease brain

Katherine J Kopeikina, George A Carlson, Rose Pitstick, Adam E Ludvigson, Alan Peters, Jennifer I Luebke, Robert M Koffie, Matthew P Frosch, Bradley T Hyman, Tara L Spires-Jones

Research output: Contribution to journalArticlepeer-review

Abstract

Neurofibrillary tangles (NFT), intracellular inclusions of abnormal fibrillar forms of microtubule associated protein tau, accumulate in Alzheimer's disease (AD) and other tauopathies and are believed to cause neuronal dysfunction, but the mechanism of tau-mediated toxicity are uncertain. Tau overexpression in cell culture impairs localization and trafficking of organelles. Here we tested the hypothesis that, in the intact brain, changes in mitochondrial distribution occur secondary to pathological changes in tau. Array tomography, a high-resolution imaging technique, was used to examine mitochondria in the reversible transgenic (rTg)4510, a regulatable transgenic, mouse model and AD brain tissue. Mitochondrial distribution is progressively disrupted with age in rTg4510 brain, particularly in somata and neurites containing Alz50-positive tau aggregates. Suppression of soluble tau expression with doxycycline resulted in complete recovery of mitochondrial distribution, despite the continued presence of aggregated tau. The effect on mitochondrial distribution occurs without concomitant alterations in neuropil mitochondrial size, as assessed by both array tomography and electron microscopy. Similar mitochondrial localization alterations were also observed in human AD tissue in Alz50+ neurons, confirming the relevance of tau to mitochondrial trafficking observed in this animal model. Because abnormalities reverted to normal if soluble tau was suppressed in rTg4510 mice, even in the continued presence of fibrillar tau inclusions, we suggest that soluble tau plays an important role in mitochondrial abnormalities, which likely contribute to neuronal dysfunction in AD.
Original languageEnglish
Pages (from-to)2071-82
Number of pages12
JournalAmerican Journal of Pathology
Volume179
Issue number4
DOIs
Publication statusPublished - Oct 2011

Keywords

  • Aged
  • Aged, 80 and over
  • Aging
  • Alzheimer Disease
  • Animals
  • Brain
  • Disease Models, Animal
  • Female
  • Humans
  • Male
  • Mice
  • Mice, Transgenic
  • Middle Aged
  • Mitochondria
  • Mutant Proteins
  • Neurons
  • Organelle Size
  • Protein Structure, Quaternary
  • Solubility
  • tau Proteins

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