Ligands for Glaucoma-Associated Myocilin Discovered by a Generic Binding Assay

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• 作者：Susan D. Orwig ; Pamela V. Chi ; Yuhong Du ; Shannon E. Hill ; Marchello A. Cavitt ; Amrithaa Suntharalingam ; Katherine C. Turnage ; Chad A. Dickey ; Stefan France ; Haian Fu ; Raquel L. Lieberman
• 刊名：ACS Chemical Biology
• 出版年：2014
• 出版时间：February 21, 2014
• 年：2014
• 卷：9
• 期：2
• 页码：517-525
• 全文大小：485K
• ISSN：1554-8937

文摘

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鈥揳ctivity 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.