Ligands for glaucoma-associated myocilin discovered by a generic binding assay.

TitleLigands for glaucoma-associated myocilin discovered by a generic binding assay.
Publication TypeJournal Article
Year of Publication2014
AuthorsOrwig SD, Chi PV, Du Y, Hill SE, Cavitt MA, Suntharalingam A, Turnage KC, Dickey CA, France S, Fu H, Lieberman RL
JournalACS chemical biology
Volume9
Issue2
Pagination517-25
Date Published2014 Feb 21
ISSN1554-8937
KeywordsCytoskeletal Proteins, Drug Evaluation, Preclinical, Extracellular Matrix Proteins, Eye Proteins, Glaucoma, Open-Angle, Glycoproteins, Humans, Ligands, Models, Molecular, Mutation, Protein Binding, Protein Structure, Tertiary, Small Molecule Libraries, Structure-Activity Relationship, Surface Plasmon Resonance
Abstract

Mutations in the olfactomedin domain of myocilin (myoc-OLF) are the strongest link to inherited primary open angle glaucoma. In this recently identified protein misfolding disorder, aggregation-prone disease variants of myocilin hasten glaucoma-associated elevation of intraocular pressure, leading to vision loss. Despite its well-documented pathogenic role, myocilin remains a domain of unknown structure or function. Here we report the first small-molecule ligands that bind to the native state of myoc-OLF. To discover these molecules, we designed a general label-free, mix-and-measure, high throughput chemical assay for restabilization (CARS), which is likely readily adaptable to discover ligands for other proteins. Of the 14 hit molecules identified from screening myoc-OLF against the Sigma-Aldrich Library of Pharmacologically Active Compounds using CARS, surface plasmon resonance binding studies reveal three are stoichiometric ligand scaffolds with low micromolar affinity. Two compounds, GW5074 and apigenin, inhibit myoc-OLF amyloid formation in vitro. Structure-activity relationship-based soluble derivatives reduce aggregation in vitro as well as enhance secretion of full-length mutant myocilin in a cell culture model. Our compounds set the stage for a new chemical probe approach to clarify the biological function of wild-type myocilin and represent lead therapeutic compounds for diminishing intracellular sequestration of toxic mutant myocilin.

DOI10.1021/cb4007776
Alternate JournalACS Chem. Biol.