Project Summary/Abstract Per 2019 Alzheimer’s report, Alzheimer’s disease (AD) dire statistics include: a current patient load of 5.8 million that is projected to expand to 14 million by 2050 in the US, increases in deaths by 145% (per 2000-2017 data), and climbing healthcare costs - $290 billion in 2019. In terms of pharmacotherapy, five clinical drugs [i.e., three cholinesterase inhibitors (ChEIs), one N-methyl-D-aspartate receptor antagonist (NMDRA), and one ChEI/NMDRA combo-drug] are indicated for AD and these drugs only provide symptomatic relief - they do not slow disease progression. A triad of poor health outcomes, lack of effective drugs, and high failure rates of pipeline molecules in clinical trials has therefore increased the urgency to discover more robust anti-AD molecules with novel mechanisms for slowing disease progression. The overall objective of this grant application is to 1) synthesize derivatives of Tubastatin A (a highly selective HDA6 inhibitor, IC50 = 15 nM), 2) evaluate each derivative for binding/functional activities at individual sigma (σ) receptors, and 3) determine each compound’s ability to inhibit histone deacetylase-6 (HDAC6). Central hypothesis: single molecules designed using the multi-target-directed ligands (MTDL) paradigm could more effectively mitigate AD’s neurodegenerative pathogenic cascades and repair cognitive deficits. Evidently, in AD animal models, independent σ-1 activation or σ-2 blockade or HDAC6 inhibition commonly result in decreased neurodegeneration and improved cognitive function. Therefore, our synthesized derivatives are expected to exhibit a de-novo σ-1/HDAC6 or σ- 2/HDAC6 combo-mechanistic anti-neurodegenerative approach towards slowing AD progression or potentially modifying the disease.

Project Narrative Relevance: Alzheimer’s disease (AD) covers 70% of the dementia spectrum. It is the 6th killer of people 65 and older in the US and yet the five indicated drugs lack clinical efficacy in slowing disease progression or modifying the disease. Since the disease is multi-factorial, this project will generate single molecules (via structural modifications of Tubastatin A) endowed with combo-activity via sigma receptor signaling and histone deacetylase-6 or HDAC6 isozyme (two promising targets for countering neurodegeneration and declines in cognition), in an effort aimed at probing novel druggable mechanisms towards the ultimate development of disease modifying pharmacotherapeutics for AD.