Development of pharmacological chaperone therapy for inherited primary and juvenile open angle glaucoma
Dr. Raquel Lieberman and collaborators studied the structure and stability of myocilin, the protein most strongly linked to both adult-onset and juvenile inherited Primary Open Angle Glaucoma (POAG). Myocilin protein forms part of a matrix in the eye that is important in regulating eye pressure. Human trabecular meshwork (HTM) cells, which generate the matrix components, recognize mutant myocilin proteins and prevent them from being secreted to the matrix. However, the mutant proteins remain inside HTM cells, causing these cells to die. This results in a disrupted matrix and increased eye pressure, eventually leading to glaucoma.
To understand how mutant myocilin can cause glaucoma, Dr. Lieberman and collaborators first found a way to express and purify large quantities of normal and selected mutant versions of this protein. Next, these researchers discovered the conditions for "crystallization" of these purified proteins into a form that could be used to determine their structures. Now that they have the myocilin crystals, no doubt they will soon determine its three dimensional structure. Finally, they developed a sensitive, high-throughput assay to determine the stability of the different forms of myocilin. Dr. Lieberman will use the information and techniques generated through this award to search for a new glaucoma drug that may restore the secretion of myocilin and save the HTM cells from dying.
The study reports the first high yield expression and purification of OLF, including a new assay to compare stability, and demonstration that 4 disease-causing mutants can be stabilized to near wild-type levels by small molecules. This publication was just released.
Orwig, S. D. and Lieberman, R. L. Biophysical characterization of the olfactomedin domain of myocilin, an extracellular matrix implicated in the inherited form of glaucoma. PLoS ONE, 6(1): e16347, 2011. (doi:10.1371/journal.pone.0016347)
Orwig, S. D., Perry, C. W., Kim, L. Y., Turnage, K. C., Zhang, R., Vollrath, D., Schmidt-Krey, I., and
Lieberman, R. L. Amyloid Fibril Formation by the Glaucoma-Associated Olfactomedin
Domain of Myocilin. J Mol Biol. 2011 Dec 13. [Epub ahead of print]
First published on: June 10, 2008
Last modified on: April 12, 2011