SBIR-STTR Award

Alzheimer's disease (AD) is a debilitating mental disorder involving severe cognitive impairment. Over 10 million people are afflicted with AD, resulting in healthcare costs of $350 billion. A drug that could delay the onset and development of AD has been estimated to be worth over $50 billion. However, there is presently no effective treatment for AD. The neuropathological mechanisms of AD involves production of the neurotoxic beta-peptide (betaP) by proteolytic processing of the amyloid precursor protein (APP). The betaP becomes deposited in amyloid plaques of AD brains and mediates neuronal cell death, indicating the betaP to be a key factor in the development of AD. Multiple forms of betaP are produced by proteases known as 'gamma-secretases' that convert the amyloid precursor protein (APP) into the smaller, neurotoxic betaP. It is believed that inhibitors of gamma-secretases will block betaP production and delay the progression of neurodegeneration in AD. However, such inhibitors have not been discovered because the authentic gamma-secretases have been unknown. ActiveSite Biotech has identified the authentic gamma-secretases that produce betaP. We propose to use our proprietary technology to develop and optimize highly sensitive gamma-secretase assays in this Phase I study that will allow screening of inhibitors of gammaP production. Phase I will assess the feasibility of gamma-secretase activity assays to monitor inhibition by commercially available protease inhibitors; this Phase I study will also determine whether distinct y-secretases can be separated for more selective drug screening. Results from Phase I will be used as the basis for future Phase II investigations to screen small molecule combinatorial libraries for inhibitors of gamma-secretase activity and betaP production. These identified compounds will be developed by ActiveSite Biotech as drugs for the therapeutic treatment of Alzheimer's disease. PROPOSED COMMERCIAL APPLICATIONS: The gamma-secretase assays developed in this project are the subject of a patent application owned by Professor Vivian Hook, which she is licensing to Activesite Biotech. Upon issuance of this patent, Activesite Biotech will be in a position to exclusively sell, license, and partner the gamma-secretase assays. Activesite Biotech will use the assay to identify and develop novel, effective treatments for Alzheimer's disease (AD). The estimated market value for an effective treatment of AD is estimated to be $50 billion

Alzheimer's disease (AD) is a long-term, debilitating disorder that causes loss of memory and cognitive functions. There is an urgent need for effective therapeutic agents to ameliorate the symptoms of AD. Important molecular drug targets in AD are the gamma-secretases that produce the neurotoxic Abeta peptides in AD. The regulated secretory pathway of neurons represents the major source of secreted Abeta peptides that accumulate in extracellular amyloid plaques in AD. However, previous screens for inhibitors of gamma-secretase have only analyzed the minor constitutive secretory pathway for Abeta peptide production. Different proteases are present in the regulated secretory pathway compared to the constitutive secretory pathway. Clearly, gamma-secretase in the regulated secretory pathway must be targeted for drug inhibition to provide the greatest reduction of Abeta. Therefore, the Phase I project developed high-throughput assays for gamma-secretases in regulated secretory vesicles that produce Abeta. A candidate inhibitor of gamma-secretases was identified, which will provide the basis for design and synthesis of 'focused' and 'optimized' libraries for this Phase II project. Phase I results also indicate feasibility to find agents that selectively inhibit gamma-secretases-42 compared to gamma-secretases-40. The Phase I project also developed neuronal chromaffin cell and brain cortical neuron assays for Abeta in the regulated secretory pathway. The goal of this phase II project will be to utilize the regulated secretory vesicle as the major site and target of Abeta peptide production in neuronal cells, for identifying inhibitor molecules that selectively inhibit gamma-secretases-42 compared to gamma-secretases-40. Such inhibitors will be considered as lead compounds. In specific aim 1, efforts for 'focused' library compounds will be screened in the high throughput in vitro assays to identify inhibitors of gamma-secretases-40 and gamma-secretases-42 in chromaffin vesicles; inhibitors will then be tested in chromaffin cells for reduction of Abeta. In the second aim, further 'optimized' libraries will be designed and synthesized based on structural features of inhibitors from the 'focused' library, screened in the high throughput assays, and tested for reduction of Abeta in the regulated secretory pathway of neuronal chromaffin cells. In the third aim, lead compounds will undergo evaluation in brain neuronal cells to identify compounds that reduce production of Abeta peptides in the regulated secretory pathway. Results will likely identify novel lead compounds for future pre-clinical animal studies for development of effective drugs for AD.

Thesaurus Terms:
Alzheimer's Disease, Amyloid Protein, Aspartic Endopeptidase, Bioassay, Chromaffin Cell, Drug Discovery /Isolation, Neuron, Neuropharmacology, Protease Inhibitor, Technology /Technique Development Blood Brain Barrier, Chemical Structure Function, Drug Screening /Evaluation, Enzyme Activity, Neuritic Plaque, Nicotine, Potassium Chloride, Vesicle /Vacuole Animal Tissue, Fluorescent Dye /Probe, High Throughput Technology, Tissue /Cell Culture