Abstract
Purpose:
The vast majority of mutations in the myocilin gene leading to glaucoma are located within the 30 kDa C-terminal olfactomedin (OLF) domain. Disease-causing myocilin variants aggregate within human trabecular meshwork (TM) cells. This accumulation taxes the cells and leads to TM cell death, resulting in increased intraocular pressure, and a hastening of glaucoma-associated vision loss. Our purpose is to investigate the structural and biophysical effects of stabilizing compounds on the myocilin-OLF domain, and evaluate their ability to prevent myocilin-OLF aggregation.
Methods:
Expression and purification of the OLF domain of myocilin, development of high throughput assay to discover ligands, development of assay to monitor rate and extent of aggregation, surface plasmon resonance to evaluate binding mode, molecular biophysical characterization of formed aggregates.
Results:
Disease-associated OLF variants access a partially unfolded state under physiological conditions that increases their propensity to grow amyloid fibrils. Compounds that thermally stabilize the OLF domain, such as osmolytes and calcium ions, reduce aggregation in a compound-specific manner. Ligands discovered by high throughput screening also affect aggregation.
Conclusions:
Different categories of OLF-stabilizing small molecules, general and tailored, may prevent the accumulation of myocilin in TM cells, and thereby provide a potential new therapy for myocilin glaucoma.
Keywords: 660 proteins encoded by disease genes •
659 protein structure/function •
735 trabecular meshwork