Format

Send to

Choose Destination
Acta Neuropathol. 2019 Jun 6. doi: 10.1007/s00401-019-02032-w. [Epub ahead of print]

Tau is required for progressive synaptic and memory deficits in a transgenic mouse model of α-synucleinopathy.

Author information

1
Medical Scientist Training Program, University of Minnesota Medical School, 420 Delaware Street SE, Minneapolis, MN, 55455, USA.
2
Graduate Program in Neuroscience, University of Minnesota Medical School, 420 Delaware Street SE, Minneapolis, MN, 55455, USA.
3
Department of Neuroscience, University of Minnesota Medical School, 420 Delaware Street SE, Minneapolis, MN, 55455, USA.
4
Graduate Program in Pharmacology, University of Minnesota Medical School, 420 Delaware Street SE, Minneapolis, MN, 55455, USA.
5
Department of Pathology, Johns Hopkins University School of Medicine, 733 N Broadway, Baltimore, MD, 21205, USA.
6
Institute for Translational Neuroscience, University of Minnesota Medical School, 420 Delaware Street SE, Minneapolis, MN, 55455, USA.
7
Mouse Behavior Core, University of Minnesota Medical School, 420 Delaware Street SE, Minneapolis, MN, 55455, USA.
8
N. Budd Grossman Center for Memory Research and Care, University of Minnesota Medical School, 420 Delaware Street SE, Minneapolis, MN, 55455, USA.
9
Department of Neuroscience, University of Minnesota Medical School, 420 Delaware Street SE, Minneapolis, MN, 55455, USA. mklee@umn.edu.
10
Institute for Translational Neuroscience, University of Minnesota Medical School, 420 Delaware Street SE, Minneapolis, MN, 55455, USA. mklee@umn.edu.
11
Geriatric Research Education and Clinical Center, Minneapolis Veterans Affairs Health Care System, University of Minnesota Medical School, 420 Delaware Street SE, Minneapolis, MN, 55455, USA. mklee@umn.edu.

Abstract

Parkinson's disease dementia (PDD) and dementia with Lewy bodies (DLB) are clinically and neuropathologically highly related α-synucleinopathies that collectively constitute the second leading cause of neurodegenerative dementias. Genetic and neuropathological studies directly implicate α-synuclein (αS) abnormalities in PDD and DLB pathogenesis. However, it is currently unknown how αS abnormalities contribute to memory loss, particularly since forebrain neuronal loss in PDD and DLB is less severe than in Alzheimer's disease. Previously, we found that familial Parkinson's disease-linked human mutant A53T αS causes aberrant localization of the microtubule-associated protein tau to postsynaptic spines in neurons, leading to postsynaptic deficits. Thus, we directly tested if the synaptic and memory deficits in a mouse model of α-synucleinopathy (TgA53T) are mediated by tau. TgA53T mice exhibit progressive memory deficits associated with postsynaptic deficits in the absence of obvious neuropathological and neurodegenerative changes in the hippocampus. Significantly, removal of endogenous mouse tau expression in TgA53T mice (TgA53T/mTau-/-), achieved by mating TgA53T mice to mouse tau-knockout mice, completely ameliorates cognitive dysfunction and concurrent synaptic deficits without affecting αS expression or accumulation of selected toxic αS oligomers. Among the known tau-dependent effects, memory deficits in TgA53T mice were associated with hippocampal circuit remodeling linked to chronic network hyperexcitability. This remodeling was absent in TgA53T/mTau-/- mice, indicating that postsynaptic deficits, aberrant network hyperactivity, and memory deficits are mechanistically linked. Our results directly implicate tau as a mediator of specific human mutant A53T αS-mediated abnormalities related to deficits in hippocampal neurotransmission and suggest a mechanism for memory impairment that occurs as a consequence of synaptic dysfunction rather than synaptic or neuronal loss. We hypothesize that these initial synaptic deficits contribute to network hyperexcitability which, in turn, exacerbate cognitive dysfunction. Our results indicate that these synaptic changes present potential therapeutic targets for amelioration of memory deficits in α-synucleinopathies.

KEYWORDS:

Dementia; Lewy body disease; Neuronal plasticity; Parkinson’s disease; Tau; α-Synuclein

PMID:
31168644
DOI:
10.1007/s00401-019-02032-w

Supplemental Content

Full text links

Icon for Springer
Loading ...
Support Center