Primary open angle glaucoma (POAG), the most common form of glaucoma, is usually accompanied by elevated intraocular pressure (IOP) due to failure of the trabecular meshwork (TM) to maintain normal levels of aqueous humor outflow. We recently generated a novel transgenic murine model (Tg-MYOCY437H) that expresses mutant myocilin, a known leading genetic cause of POAG in humans and replicates human glaucoma phenotypes. Importantly, we have associated endoplasmic reticulum (ER) stress to the pathogenesis of glaucoma in Tg-MYOCY437H mice. Misfolded myocilin accumulates in the ER, induces ER stress and activates a protective unfolded protein response (UPR). Along with UPR activation, mutant myocilin also induces autophagy, a process of lysosomal degradation known to degrade protein aggregates. However, failure to eliminate myocilin aggregates possibly due to insufficient UPR and impaired autophagy, TM cells induce the ER stress-initiated apoptotic transcriptional factor, Chop, which may further worsen ER homeostasis and cause TM dysfunction/loss, elevating IOP and resulting in POAG. The current proposal will further investigate the role of chronic ER stress in the pathogenesis of myocilin as well as non-myocilin associated POAG. During the mentored phase, the proposed studies will determine whether failure to activate the protective UPR (Atf-6?-/-) exacerbates glaucoma phenotypes, whereas interference with ER stress-induced apoptosis (Chop-/-) prevents glaucoma in Tg-MYOCY437H mice. In addition, we will investigate whether ER stress is activated in port-mortem TM tissues from POAG donors. During the independent phase, we will examine whether induction of ER stress in the TM is associated with elevation of IOP in a mouse model of dexamethasone-induced ocular hypertension. In addition, we will examine the role of autophagy in degradation of myocilin aggregates and will determine whether inducing autophagy by rapamycin will rescue the glaucoma of Tg-MYOCY437H mice. Specifically, the candidate will learn and generate new models of ER stress using Atf6? and Chop knockout mice, generate induced pluripotent stem cells (iPSCs)-derived trabecular meshwork- like cells from POAG patients, and characterize a dexamethasone-induced ocular hypertension mouse model in the laboratory of Dr. Val Sheffield. Additionally, during the mentored phase, the candidate will continue his professional and scientific career development through continual guidance from the advisory committee. He will attend scientific conferences, and collaborate with ER stress expert, Dr. Thomas Rutkowski and glaucoma clinical expert, Dr. Lee Alward. He will also acquire teaching experience. This project will facilitate continued technical, intellectual, and professional training of the candidate, and assist the candidate in the establishment of an independent research laboratory at an academic research institute.

Public Health Relevance

The successful completion of this project will lead to insight into elevated intraocular pressure, a major risk factor of the human blinding disorder, primary open angle glaucoma. The results will potentially improve diagnosis, genetic risk assessment and treatment of this common disorder.

National Institute of Health (NIH)
National Eye Institute (NEI)
Research Transition Award (R00)
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No Study Section (in-house review) (NSS)
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Chin, Hemin R
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University of North Texas
Anatomy/Cell Biology
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Fort Worth
United States
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Maddineni, Prabhavathi; Kasetti, Ramesh B; Zode, Gulab S (2018) Methods for Analyzing Endoplasmic Reticulum Stress in the Trabecular Meshwork of Glaucoma Models. Methods Mol Biol 1695:121-134
Kasetti, Ramesh B; Maddineni, Prabhavathi; Patel, Pinkal D et al. (2018) Transforming growth factor ?2 (TGF?2) signaling plays a key role in glucocorticoid-induced ocular hypertension. J Biol Chem 293:9854-9868
Keller, Kate E; Bhattacharya, Sanjoy K; Borrás, Theresa et al. (2018) Consensus recommendations for trabecular meshwork cell isolation, characterization and culture. Exp Eye Res 171:164-173
Kasetti, Ramesh B; Maddineni, Prabhavathi; Millar, J Cameron et al. (2017) Increased synthesis and deposition of extracellular matrix proteins leads to endoplasmic reticulum stress in the trabecular meshwork. Sci Rep 7:14951
Patel, Gaurang C; Phan, Tien N; Maddineni, Prabhavathi et al. (2017) Dexamethasone-Induced Ocular Hypertension in Mice: Effects of Myocilin and Route of Administration. Am J Pathol 187:713-723
Jain, Ankur; Zode, Gulab; Kasetti, Ramesh B et al. (2017) CRISPR-Cas9-based treatment of myocilin-associated glaucoma. Proc Natl Acad Sci U S A 114:11199-11204
Zadoo, Serena; Nguyen, Annie; Zode, Gulab et al. (2016) A Novel Luciferase Assay For Sensitively Monitoring Myocilin Variants in Cell Culture. Invest Ophthalmol Vis Sci 57:1939-50
Kasetti, Ramesh B; Phan, Tien N; Millar, J Cameron et al. (2016) Expression of Mutant Myocilin Induces Abnormal Intracellular Accumulation of Selected Extracellular Matrix Proteins in the Trabecular Meshwork. Invest Ophthalmol Vis Sci 57:6058-6069
Lu, Wennan; Hu, HuiLing; Sévigny, Jean et al. (2015) Rat, mouse, and primate models of chronic glaucoma show sustained elevation of extracellular ATP and altered purinergic signaling in the posterior eye. Invest Ophthalmol Vis Sci 56:3075-83
Peters, Joseph C; Bhattacharya, Sanjoy; Clark, Abbot F et al. (2015) Increased Endoplasmic Reticulum Stress in Human Glaucomatous Trabecular Meshwork Cells and Tissues. Invest Ophthalmol Vis Sci 56:3860-8

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