Differential induction and spread of tau pathology in young PS19 tau transgenic mice following intracerebral injections of pathological tau from Alzheimer’s disease or corticobasal degeneration brains

• DOI: 10.1007/s00401-014-1373-0
• Publication Date: 2014-12-22T22:33:21Z
• Authors: Susana Boluda; Michiyo Iba; Bin Zhang; Kevin M. Raible; Virginia M-Y. Lee; John Q. Trojanowski
• Keywords: Neurons; 0303 health sciences; Blotting, Western; Brain; Enzyme-Linked Immunosorbent Assay; Mice, Transgenic; tau Proteins; Immunohistochemistry; 3. Good health; 03 medical and health sciences; Tauopathies; Alzheimer Disease; Animals; Humans; Brain Tissue Transplantation; Down Syndrome; Neuroglia

Filamentous tau pathologies are hallmark lesions of several neurodegenerative tauopathies including Alzheimer's disease (AD) and corticobasal degeneration (CBD) which show cell type-specific and topographically distinct tau inclusions. Growing evidence supports templated transmission of tauopathies through functionally interconnected neuroanatomical pathways suggesting that different self-propagating strains of pathological tau could account for the diverse manifestations of neurodegenerative tauopathies. Here, we describe the rapid and distinct cell type-specific spread of pathological tau following intracerebral injections of CBD or AD brain extracts enriched in pathological tau (designated CBD-Tau and AD-Tau, respectively) in young human mutant P301S tau transgenic (Tg) mice (line PS19) ~6-9 months before they show onset of mutant tau transgene-induced tau pathology. At 1 month post-injection of CBD-Tau, tau inclusions developed predominantly in oligodendrocytes of the fimbria and white matter near the injection sites with infrequent intraneuronal tau aggregates. In contrast, injections of AD-Tau in young PS19 mice induced tau pathology predominantly in neuronal perikarya with little or no oligodendrocyte involvement 1 month post-injection. With longer post-injection survival intervals of up to 6 months, CBD-Tau- and AD-Tau-induced tau pathology spread to different brain regions distant from the injection sites while maintaining the cell type-specific pattern noted above. Finally, CA3 neuron loss was detected 3 months post-injection of AD-Tau but not CBD-Tau. Thus, AD-Tau and CBD-Tau represent specific pathological tau strains that spread differentially and may underlie distinct clinical and pathological features of these two tauopathies. Hence, these strains could become targets to develop disease-modifying therapies for CBD and AD.