High throughput tau oligomer assay for drug screening for Alzheimer's disease

Moe, James

Abstract

There is a critical unmet need for novel drugs that prevent or ameliorate the molecular pathogenesis of Alzheimer's disease (AD). AD results in progressive memory loss, changes in personality and behavior, and decreasing ability to perform complex and even simple tasks, with the result that severely affected individuals require constant care. The disease pathology is characterized by extracellular and intracellular accumulations of insoluble fibrils and tangles, and amyloid plaques. These insoluble protein deposits are composed of either tau protein associated with neurofibrillary tangles (NFTs), or ?-amyloid (A-?) protein associated with senile plaques. An in vitro system was assembled, in which key events of the tau protein misfolding and oligomerization were achieved under physiological conditions using small, highly structured RNA chaperones (shsRNA). Tau formed oligomers and filaments under these conditions depending on the reaction conditions, and the sequence of the shsRNA used. The oligomers and filaments that formed were biochemically, and structurally similar to those found in Alzheimer's disease (AD) and were therefore amyloid-like. The central aim of the proposed program is to take the tau in vitro oligomerization assay and convert it to a high throughput format suitable for screening chemical libraries for hits, and for lead optimization studies.
The specific aims that will be accomplished are: Optimize and characterize the tau in vitro oligomer assay? Isolate and characterize tau oligomer specific antibodies using phage display? Develop a time resolved fluorescence immunoassay (TRFIA) for the detection of tau bloomers? Convert tau oligomer specific assay (TOSA) to high throughput a-screen format Preliminary validation of the TOSA will be accomplished using tool compound testing. During phase II, the tau oligomer specific antibody will be used in brain slices from Alzheimer's disease patients, to show that it reacts with neurofibrillar tangles or their precursors to validate the platform as a drug target. The TOSA will be marketed as a tool for drug discovery for Alzheimer's disease and other appropriate taupathies to the pharmaceutical and biopharmaceutical industries. The proposed program will take Q-RNA's expertise in generating tau oligomers using molecular facilitator's and combine this with the expertise of Dr. Michael Sierks at the ASU in screening phage libraries to isolate oligomer specific scFvs to develop a rapid, low cost, in vitro drug screening platform that will be used for identifying compounds that inhibit or ameliorate tau oligomerization. ? ? ?