RCMI Pilot Project

January 1, 2020 – December 31, 2020

 

PI:  Jayalakshmi Sridhar, Ph.D.

 

Title: Development of Casein Kinase 1 delta/epsilon Inhibitors with Improved Potency

Abstract

Based on 2020 data, an estimated 6.2 million Americans age 65 and older are living with Alzheimer’s disease (AD) – a number that is projected to rise to 12.7 million by 2050. Of particular interest to this proposal, older African American (AA) and Hispanic Americans are twice as likely as non-Hispanic whites to develop AD. Although AD is underreported and generally diagnosed at a later stage in AA adults, AA currently constitute 20% of AD patients – a number that is projected to increase to 42% by 2050. As such, there is an urgent need to address this current and growing health disparity.  One of the key hallmarks of AD is tauopathy, the presence of neurofibrillary tangles (NFTs) in brain tissue.  NFTs are aggregates of tau, a protein that normally binds to and stabilizes the microtubule network in neurons.  The transition from tau’s physiological association with the microtubule to the unbound form that leads to NFTs is due to the hyperphosphorylation of tau by a number of cellular kinases leading to its dissociation from microtubules. Preventing hyperphosphorylation of tau is thus a key target for the development of novel therapeutics for AD.  Our project targets the inhibition of casein kinase 1 d/e that are known to phosphorylate the tau protein at residues involved in microtubule binding. Our laboratory has identified two classes of molecules that inhibit casein kinase 1d/e, blocking tau phosphorylation in cell-based assays. The goal of this proposal is to optimize these lead compounds to potential therapeutics with increased potency. Computational molecular modeling tools will be used to design new derivatives that will be synthesized using organic synthetic methods. To determine the efficacy of these new compounds in the inhibition of CK1d/e, a reconstituted biochemical assay of tau phosphorylation using purified components followed by microtubule affinity assays to show that inhibiting CK1-dependent phosphorylation of tau maintains the physiologically relevant role of tau and blocks the pathological development of NFTs. 

Specific Aim 1: In-silico design of the molecule series with improved potency/selectivity profile for CK1d/e. This will be done using (a) computational modeling tools for design of new derivatives to create a derivative database and perform docking studies, and (b) in silico evaluation of the designed molecules for their blood brain barrier penetrating capabilities.

Specific Aim 2: Generation and testing of novel CK1d/e inhibitors.  This will involve (a) synthesis of the designed molecules and (b) in vitro FRET-based assays to evaluate their CK1d/e inhibition.

Kinase inhibition assays and tau phosphorylation status assays have been standardized. Bioassays will be performed in our collaborator Dr. Thomas Huckaba’s laboratory. The compounds developed through this process can serve as potential therapeutics for AD after further pre-clinical and clinical testing. This project contributes to the overall goal of expanding diversity in the biomedical research community, particularly train minority undergraduate students in the research techniques.