Improved long-term potentiation and memory in young tau-P301L transgenic mice before onset of hyperphosphorylation and tauopathy.
The microtubule binding protein tau is implicated in neurodegenerative tauopathies, including frontotemporal dementia (FTD) with Parkinsonism caused by diverse mutations in the tau gene. Hyperphosphorylation of tau is considered crucial in the age-related formation of neurofibrillary tangles (NFTs) correlating well with neurotoxicity and cognitive defects. Transgenic mice expressing FTD mutant tau-P301L recapitulate the human pathology with progressive neuronal impairment and accumulation of NFT. Here, we studied tau-P301L mice for parameters of learning and memory at a young age, before hyperphosphorylation and tauopathy were apparent. Unexpectedly, in young tau-P301L mice, increased long-term potentiation in the dentate gyrus was observed in parallel with improved cognitive performance in object recognition tests. Neither tau phosphorylation, neurogenesis, nor other morphological parameters that were analyzed could account for these cognitive changes. The data demonstrate that learning and memory processes in the hippocampus of young tau-P301L mice are not impaired and actually improved in the absence of marked phosphorylation of human tau. We conclude that protein tau plays an important beneficial role in normal neuronal processes of hippocampal memory, and conversely, that not tau mutations per se, but the ensuing hyperphosphorylation must be critical for cognitive decline in tauopathies.
Boekhoorn
Karin
K
Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, 1098 SM Amsterdam, The Netherlands.
Terwel
Dick
D
Biemans
Barbara
B
Borghgraef
Peter
P
Wiegert
Olof
O
Ramakers
Ger J A
GJ
de Vos
Koos
K
Krugers
Harm
H
Tomiyama
Takami
T
Mori
Hiroshi
H
Joels
Marian
M
van Leuven
Fred
F
Lucassen
Paul J
PJ
D000818:Animals; D002478:Cells, Cultured; D004195:Disease Models, Animal; D018450:Disease Progression; D006624:Hippocampus / Q000166:cytology / Q000502:physiology*; D017774:Long-Term Potentiation / Q000502:physiology*; D008297:Male; D008568:Memory / Q000502:physiology*; D051379:Mice; D008822:Mice, Transgenic; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D010766:Phosphorylation; D024801:Tauopathies / Q000473:pathology / Q000503:physiopathology*; D013997:Time Factors; D016875:tau Proteins / Q000235:genetics / Q000378:metabolism*
D016875:tau Proteins