Abstract
Pathological tau propagates in a stereotypical manner in Alzheimer’s Disease (AD), spreading from the somatodendritic compartment of neurons in the entorhinal cortex (EC) during the early stages. To date, much of the work examining tau propagation has been performed using mutated or pathological tau, transgenic animal models, or a combination of these. This is the first study comparing the propagation pattern of 2N4R human tau with that of truncated K18 P301L tau in a wild-type C57BL/6J mouse model. This mouse model has a well-defined connectome. 2N4R is of particular interest, as this isoform has the same 4R structure as the commonly used P301L mutated tau. At P56, C57BL/6J mice will be injected with 2 μg of 2N4R tau, K18 P301L tau, or a vehicle solution in the entorhinal cortex. Mice will be sacrificed 24hr after 1 injection, 24hrs after 5 days of injections, or 1, 2, 4, 10, or 13 weeks after 5 days of injections. To date, injections of nonmutated tau have been confirmed using the AT8 antibody. However, a high level of background signal is occurring during fluorescent staining. We have since shifted staining and microscopy techniques to DAB and brightfield imaging for the purposes of antibody validation. Results of the Val256 and Ser356 antibodies show high background and no signal in both staining techniques. AT8 staining is showing some staining following injections of the vehicle solution. However, staining levels are higher in the 2N4R injection groups. New antibodies targeting the amino acid regions 162-175 and 268-312 have been received and are being tested. We will also begin perfusing tissues, which is a technique that removes blood from the brain and may reduce background signals, during collection.
Short bio
My name is Daniel Lamontagne-Kam and I’m a pharmacology PhD student in the laboratory of Dr. Jonathan Brouillette at l’Université de Montréal in the Département de Pharmacologie et Physiologie. I’m currently working with Arsalan Rahimabadi and Dr. Habib Benali on a project investigating the propagation of tau in a C57BL/6J mouse model. As a team, we presented preliminary results this past May at the Canadian Association of Neuroscience conference in Montreal. The presentation was titled “Anterograde and retrograde propagation of tau between the hippocampus and entorhinal cortex in mice”.