Glaucoma is a major cause of blindness, characterized by the death of retinal ganglion cells (RGCs) and loss of vision. An elevated intraocular pressure (IOP) is the biggest risk factor in the disease, but localized inflammatory signaling can also contribute to the pathology. This proposal will investigate the pathways linking elevated IOP to local inflammatory signaling and RGC death, based on the innovative hypothesis that ATP-dependent release of the inflammatory cytokine ?IL-1? from microglial cells links mechanical strain to vision loss in glaucoma. Stretch- dependent ATP release from optic nerve head astrocytes will be compared using astrocytes missing genes implicated in mechanosensitive ATP release. The most promising candidates will be examined in vivo using a mouse model for chronic ocular hypertension; reduced levels of inflammatory responses or RGC death will implicate mechanosensitive ATP release. The ability of ATP to enhance microglial migration and IL-1? release will be explored in isolated retinal microglial cells to enable detailed characterization. The contribution to RGCs death in a model of chronic ocular hypertension will be confirmed. The ability of IL-1? to kill RGCs in vivo will be confirmed and its contribution to death in ocular hypertension tested. The effect of substrate stiffness on the magnitude of mechanosensitive ATP release will be investigated in vitro and in vivo. Finally, the links between ATP release and IL-1? will be confirmed in the retina of glaucomatous humans. In summary, this proposal will connect elevated IOP with proinflammatory responses through aberrant purinergic signaling. This novel hypothesis will advance our understanding of glaucoma while identifying possible new targets for intervention.

Public Health Relevance

Glaucoma is a major cause of blindness associated with the loss of retinal ganglion cells. Increased intraocular pressure (IOP) has long been recognized as a major risk factor, but the mechanisms linking elevated IOP to retinal ganglion cell pathology remain unclear. This project will investigate how the elevated IOP of glaucoma leads to increased inflammatory signaling in the posterior eye, and examine the role for aberrant purinergic signaling and microglial cells in the process with the aim of identifying potential points of intervention.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY015537-14
Application #
10130529
Study Section
Diseases and Pathophysiology of the Visual System Study Section (DPVS)
Program Officer
Greenwell, Thomas
Project Start
2005-06-01
Project End
2024-02-29
Budget Start
2021-03-01
Budget End
2022-02-28
Support Year
14
Fiscal Year
2021
Total Cost
Indirect Cost
Name
University of Pennsylvania
Department
Anatomy/Cell Biology
Type
Schools of Dentistry/Oral Hygn
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
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Beckel, Jonathan M; Gómez, Néstor Más; Lu, Wennan et al. (2018) Stimulation of TLR3 triggers release of lysosomal ATP in astrocytes and epithelial cells that requires TRPML1 channels. Sci Rep 8:5726
Ventura, Ana Lucia Marques; Dos Santos-Rodrigues, Alexandre; Mitchell, Claire H et al. (2018) Purinergic signaling in the retina: From development to disease. Brain Res Bull :
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Gómez, Néstor Más; Lu, Wennan; Lim, Jason C et al. (2018) Robust lysosomal calcium signaling through channel TRPML1 is impaired by lysosomal lipid accumulation. FASEB J 32:782-794
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Albalawi, Farraj; Lu, Wennan; Beckel, Jonathan M et al. (2017) The P2X7 Receptor Primes IL-1? and the NLRP3 Inflammasome in Astrocytes Exposed to Mechanical Strain. Front Cell Neurosci 11:227
Lu, Wennan; Albalawi, Farraj; Beckel, Jonathan M et al. (2017) The P2X7 receptor links mechanical strain to cytokine IL-6 up-regulation and release in neurons and astrocytes. J Neurochem 141:436-448
Workman, Alan D; Carey, Ryan M; Chen, Bei et al. (2017) CALHM1-Mediated ATP Release and Ciliary Beat Frequency Modulation in Nasal Epithelial Cells. Sci Rep 7:6687
Beckel, Jonathan M; Lu, Wennan; Civan, Mortimer M et al. (2016) Treatment of Retinal Disorders with Purinergic Drugs: Beyond Receptors. J Ocul Pharmacol Ther 32:488-489

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