Glaucoma is the most common cause of irreversible blindness and will affect more than 100 million people between 40 to 80 years old by 2040. It causes severe visual loss due to degeneration of optic nerve (ON) and retinal ganglion cells (RGCs). There is a significant unmet clinical need for neuroprotectants. Our previous studies of ON traumatic injury and glaucoma demonstrated that both acute and chronic ON injury induce endoplasmic reticulum (ER) stress in RGCs. We were able to protect the injured RGC soma and axons if we blocked the detrimental effects of ER stress by manipulating two key downstream molecules of the unfolded protein response (UPR) in opposite ways: a) deletion of CCAAT/enhancer binding protein homologous protein (CHOP), and/or b) activation of X-box binding protein 1 (XBP-1). Thus axon injury-induced ER stress may be a common mechanism of neuronal damage and targeting neuronal ER stress may have considerable therapeutic neuroprotective potential in diseases associated with axonopathy. As the first step, we propose to identify novel ER stress modulators by screening chemical libraries with cell-based high throughput screen (HTS) assays; and then to validate whether these agents promote RGC and ON survival and preserve visual function in mouse glaucoma models. Recently, exciting recent studies of axonal Wallerian degeneration have shown that several key molecules involved in axonal NAD+ metabolism are critical for axonal degeneration. SARM1 (Sterile Alpha and TIR Motif 1), for example, is negatively regulated by axonal NAD+ synthetic enzyme nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2) to induce axon degeneration; deletion of SARM1 or activation of axonal NMNATs results in axon protection. Thus, we will test the hypothesis that modulating both intrinsic neuronal ER stress and NAD+ metabolism will synergistically prevent both RGC soma and axon (ON) degeneration and preserve vision in glaucoma. This study may generate novel combinatory therapeutic strategies that lead to more efficient neuroprotection in patients. And finally, we will develop novel in vivo imaging tools for RGC morphology and function studies and acquire much needed insights into the mechanism of RGC ER stress initiation. We expect the results through these studies will provide essential information for clinical application of ER stress modulation, and establish translatable techniques and biomarkers that will greatly facilitate clinical management of glaucoma patients.

Public Health Relevance

Glaucoma is the most common cause of irreversible blindness and will affect more than 100 million people between 40 to 80 years old by 2040. Based on our previous work that revealed the significant therapeutic potential of ER stress modulation for glaucomatous degeneration of optic nerve and retinal ganglion cells (RGCs), the proposed experiments will continue to develop novel neuroprotective strategies to preserve RGC and ON integrity and visual function.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
2R01EY023295-06A1
Application #
9660388
Study Section
Diseases and Pathophysiology of the Visual System Study Section (DPVS)
Program Officer
Liberman, Ellen S
Project Start
2013-03-01
Project End
2023-02-28
Budget Start
2019-03-01
Budget End
2020-02-29
Support Year
6
Fiscal Year
2019
Total Cost
Indirect Cost
Name
Stanford University
Department
Ophthalmology
Type
Schools of Medicine
DUNS #
009214214
City
Stanford
State
CA
Country
United States
Zip Code
94305
Zhang, Jie; Yang, Dakai; Huang, Haoliang et al. (2018) Coordination of Necessary and Permissive Signals by PTEN Inhibition for CNS Axon Regeneration. Front Neurosci 12:558
Huang, Haoliang; Miao, Linqing; Liang, Feisi et al. (2017) Neuroprotection by eIF2?-CHOP inhibition and XBP-1 activation in EAE/optic neuritiss. Cell Death Dis 8:e2936
Prosseda, Philipp P; Luo, Na; Wang, Biao et al. (2017) Loss of OCRL increases ciliary PI(4,5)P2 in Lowe oculocerebrorenal syndrome. J Cell Sci 130:3447-3454
Wang, Qizhao; Wu, Zhongren; Zhang, Junping et al. (2017) A Robust System for Production of Superabundant VP1 Recombinant AAV Vectors. Mol Ther Methods Clin Dev 7:146-156
Hu, Yang (2016) Axon injury induced endoplasmic reticulum stress and neurodegeneration. Neural Regen Res 11:1557-1559
Miao, Linqing; Yang, Liu; Huang, Haoliang et al. (2016) mTORC1 is necessary but mTORC2 and GSK3? are inhibitory for AKT3-induced axon regeneration in the central nervous system. Elife 5:e14908
Yang, Liu; Li, Shaohua; Miao, Linqing et al. (2016) Rescue of Glaucomatous Neurodegeneration by Differentially Modulating Neuronal Endoplasmic Reticulum Stress Molecules. J Neurosci 36:5891-903
Hu, Yang (2015) The necessary role of mTORC1 in central nervous system axon regeneration. Neural Regen Res 10:186-8
Yang, Liu; Miao, Linqing; Liang, Feisi et al. (2014) The mTORC1 effectors S6K1 and 4E-BP play different roles in CNS axon regeneration. Nat Commun 5:5416
Li, Shaohua; Yang, Liu; Selzer, Michael E et al. (2013) Neuronal endoplasmic reticulum stress in axon injury and neurodegeneration. Ann Neurol 74:768-77