Dendritic Degeneration, Neurovascular Defects, and Inflammation Precede Neuronal Loss in a Mouse Model for Tau-Mediated Neurodegeneration

Tomasz Jaworski, Benoit Lechat, David Demedts, Lies Gielis, Herman Devijver, Peter Borghgraef, Hans Duimel, Fons Verheyen, Sebastian Kuegler, Fred Van Leuven*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

76 Citations (Web of Science)

Abstract

Adeno-associated virus (AAV)-mediated expression of wild-type or mutant P301L protein tau produces massive degeneration of pyramidal neurons without protein tau aggregation. We probed this novel model for genetic and structural factors and early parameters of pyramidal neurodegeneration. In yellow fluorescent protein expressing transgenic mice, intracerebral injection of AAV-tauP301L revealed early damage to apical dendrites of CA1 pyramidal neurons, whereas their somata remained normal. Ultrastructurally, more and enlarged autophagic vacuoles were contained in degenerating dendrites and manifested as dark, discontinuous, vacuolated processes surrounded by activated astrocytes. Dendritic spines were lost in AAV-tauP301L-injected yellow fluorescent protein-expressing transgenic mice, and ultrastructurally, spines appeared dark and degenerating. In CX3CR1(EGFP/EGFP)-deficient mice, microglia were recruited early to neurons expressing human tau. The inflammatory response was accompanied by extravasation of plasma immunoglobulins alpha 2-Macroglobulin, but neither albumin nor transferrin, became lodged in the brain parenchyma. Large proteins, but not Evans blue, entered the brain of mice injected with AAV-tauP301L. Ultrastructurally, brain capillaries were constricted and surrounded by swollen astrocytes with extensions that contacted degenerating dendrites and axons. Together, these data corroborate the hypothesis that neuroinflammation participates essentially in tau-mediated neurodegeneration, and the model recapitulates early dendritic defects reminiscent of "dendritic amputation" in Alzheimer's disease. (Am J Pathol 2011, 179:2001-2015; DOI: 10.1016/j.ajpath.2011.06.025)
Original languageEnglish
Pages (from-to)2001-2015
JournalAmerican Journal of Pathology
Volume179
Issue number4
DOIs
Publication statusPublished - Oct 2011

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