Neural regulation of tear production and in particular of lacrimal gland secretion is critical to a healthy ocular surface. Parasympathetic and sympathetic neurotransmitters induce lacrimal gland secretion of protein, electrolytes, and water by using three distinct signaling pathways. In spite of the multitude of pathways, with aging and in Sjogren's syndrome, lacrimal gland secretion fails and dry eye results. In dry eye is a lymphocyte-mediated inflammation blocks neurally stimulated secretion by the lacrimal gland. Determination of the alterations in the cellular signaling pathways that account for the loss of secretion depends upon knowledge of the normal neural signaling pathways. The long-term objective is to investigate the types of purinergic receptors activated by nucleotides in the lacrimal gland, evaluate receptor function, and determine if their dysfunction contributes to the loss of secretion that accompanies inflammation that develops with aging and in Sjogren's syndrome. The following specific aims will be investigated: 1. How does extracellular ATP activate P2X7 receptors and stimulate protein secretion in the lacrimal gland? 2. Do cholinergic and alpha 1-adrenergic agonists release ATP in the lacrimal gland, is ATP released from nerves, myoepithelial cells, or acinar cells, and which signaling pathways does ATP activate in acinar cells? and 3. Does prolonged stimulation of P2X7 receptors activate second messengers that induce pore formation, IL-1beta release, and/or cell death and does this play a role in the secretory failure or cell death that occurs in a mouse model of lacrimal gland dysfunction? The presence of P2X7 receptors will be investigated by RT- PCR, western blotting and immunofluorescence microscopy in acinar cells from rat lacrimal glands. The function of these receptors will be determined by measuring intracellular [Ca2+] and protein secretion. The mechanism and site of cholinergic and alphal-adrenergic agonist release of ATP will be assessed in tissue pieces, myoepithelial cells, and acinar cells by enzymatic assay. The effect of prolonged activation of P2X7 receptors will be determined by measuring pore formation, interleukin 1beta release, and cell death. P2X7 receptor knockout mice and a mouse model of Sjogren's syndrome will be used. Knowledge about the molecules inside lacrimal gland cells that cause secretion will be critical to the development of new drugs to produce tear secretion in individuals who have dry eye resulting from aging or Sjogren's syndrome.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY006177-26
Application #
7751220
Study Section
Anterior Eye Disease Study Section (AED)
Program Officer
Mckie, George Ann
Project Start
1985-06-01
Project End
2012-12-31
Budget Start
2011-01-01
Budget End
2012-12-31
Support Year
26
Fiscal Year
2011
Total Cost
$499,103
Indirect Cost
Name
Schepens Eye Research Institute
Department
Type
DUNS #
073826000
City
Boston
State
MA
Country
United States
Zip Code
02114
Shatos, Marie A; Hodges, Robin R; Morinaga, Masahiro et al. (2016) Alteration in cellular turnover and progenitor cell population in lacrimal glands from thrombospondin 1(-/-) mice, a model of dry eye. Exp Eye Res 153:27-41
Sanderson, Julie; Dartt, Darlene A; Trinkaus-Randall, Vickery et al. (2014) Purines in the eye: recent evidence for the physiological and pathological role of purines in the RPE, retinal neurons, astrocytes, Müller cells, lens, trabecular meshwork, cornea and lacrimal gland. Exp Eye Res 127:270-9
Contreras-Ruiz, Laura; Ryan, Denise S; Sia, Rose K et al. (2014) Polymorphism in THBS1 gene is associated with post-refractive surgery chronic ocular surface inflammation. Ophthalmology 121:1389-97
Dartt, D A; Willcox, M D P (2013) Complexity of the tear film: importance in homeostasis and dysfunction during disease. Exp Eye Res 117:1-3
Shatos, Marie A; Haugaard-Kedstrom, Linda; Hodges, Robin R et al. (2012) Isolation and characterization of progenitor cells in uninjured, adult rat lacrimal gland. Invest Ophthalmol Vis Sci 53:2749-59
Hodges, Robin R; Guilbert, Erin; Shatos, Marie A et al. (2011) Phospholipase D1, but not D2, regulates protein secretion via Rho/ROCK in a Ras/Raf-independent, MEK-dependent manner in rat lacrimal gland. Invest Ophthalmol Vis Sci 52:2199-210
Hodges, Robin R; Vrouvlianis, Joanna; Scott, Rachel et al. (2011) Identification of P2X₃ and P2X₇ purinergic receptors activated by ATP in rat lacrimal gland. Invest Ophthalmol Vis Sci 52:3254-63
Dartt, Darlene A; Hodges, Robin R (2011) Cholinergic agonists activate P2X7 receptors to stimulate protein secretion by the rat lacrimal gland. Invest Ophthalmol Vis Sci 52:3381-90
Dartt, Darlene A; Hodges, Robin R (2011) Interaction of alpha1D-adrenergic and P2X(7) receptors in the rat lacrimal gland and the effect on intracellular [Ca2+] and protein secretion. Invest Ophthalmol Vis Sci 52:5720-9
Ohtomo, Kaori; Shatos, Marie A; Vrouvlianis, Joanna et al. (2011) Increase of intracellular Ca2+ by purinergic receptors in cultured rat lacrimal gland myoepithelial cells. Invest Ophthalmol Vis Sci 52:9503-15

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