Screening for Nuclear Receptor TLX ligands

Project Summary
We hypothesize that high affinity synthetic agonists of TLX may enhance adult hippocampal neurogenesis
(AHN) and improve cognitive function in patients with dementia including Alzheimer's disease (AD). Here, we
focus on developing, refining, and validation of TLX assays for the purposes of performing a screen for novel,
synthetic TLX ligands that can be used as points to initiate drug discovery optimization efforts to develop TLX
agonists towards potential clinical evaluation for treatment of dementia including AD. This is an application for
a R61/R33 grant which focuses on the development and validation of assays that can be used to “identify and
characterize potential therapeutic agents for neurological or neuromuscular disorders”. We are focused on
identification of ligands targeting the nuclear receptor TLX that may hold utility to treat neurological disorders
associated with cognitive dysfunction. The R61 phase is focused on development and validation of the key in
vitro assays to identify putative TLX ligands. This is in alignment with the NIH's description of R61 activities
which include (as specifically indicated in PAR-21-124): (1) Development and validation of assay(s) (including
phenotypic assays) to support a succinct testing funnel…, (2) Development of in vitro or ex vivo
potency/efficacy assays designed to indicate the specific ability of an agent to achieve a desired biological
effect, and (3) Assay development and/or optimization for High-Throughput Screening (HTS). The R33 phase
is initiated upon successful development of the assays and testing funnel and specifically is focused on (as
specifically indicated in PAR-21-124): (1) HTS, comprising screening of large libraries for activity against
biological targets via the use of automation, miniaturized assays and large-scale data analysis, (2) Preparation
and screening of select series of therapeutic agents using…medicinal chemistry…, (3) Assessment of
therapeutic agent's properties using computational analysis and early physicochemical measurements, polar
surface area, solubility, cell permeability and efflux, (4) Assessment of initial in vitro pharmacokinetic
parameters such as absorption, distribution, metabolism, and excretion (ADME), (5) Assessment of potential
off target activities, and (5) Optimization of therapeutic agent(s) for FUTURE in vivo testing. To address these
goals, we propose the following Specific Aims: R61 phase: AIM 1– Develop, refine, and validate a biochemical
assay to detect TLX ligands in an HTS format and AIM 2 – Develop and validate secondary/tertiary assays for
the purpose of characterizing “hits” identified in a TLX screen. R33 phase: AIM 1 – Screen both
chemoinformatic driven nuclear receptor-biased chemical libraries and chemical diversity libraries using the
validated assays from the R61 Phase to identify putative TLX agonists. AIM 2 – Evaluate the hits from the
screens for their potential for further optimization as TLX agonists and perform initial structure-activity-
relationship on priority hits. Our goal is to identify TLX agonists from multiple chemical scaffolds that will be
pursued in future lead optimization studies in models of dementia and subsequently pursued in clinical studies.

Grant Number: 4R33NS133955-02
NIH Institute/Center: NIH
Principal Investigator: Thomas Burris