Sjogren's syndrome is the leading cause of aqueous tear deficient dry eye. Sjogren's syndrome is an autoimmune disease, which occurs almost exclusively in females (>90%), is associated with extensive lymphocytic accumulation in the lacrimal gland and destruction of epithelial cells resulting in insufficient fluid and protein secretion leading to dry eye. To date there are no treatments or cures for this disease. The long term objective of the present proposal is to determine, using marine models of Sjogren's syndrome, the effect of the lymphocytic accumulation in the lacrimal gland on nerve functionality, intracellular signaling pathways, and protein and fluid secretion. A second objective is to test the role of cytokines, especially interleukin-1beta (IL-1beta), in the impaired function of the lacrimal gland in Sjogren's syndrome, and if IL-1 receptor antagonist (IL-1-ra) treatment can restore lacrimal gland function. To obtain these goals, the following specific aims have been proposed: (1) determine functionality of nerves and neurotransmitters in the lacrimal gland after the onset and during the progression of the lymphocytic accumulation; (2) determine if all signaling pathways are up-regulated in the lacrimal gland with the onset and progression of lymphocytic accumulation, and if blocking this accumulation prevents the up-regulation; and (3) determine if protein and fluid secretion induced by neural stimulation of the lacrimal gland of diseased mice is altered. Lacrimal gland slices or acini will be prepared from diseased and control female mice. The release of neurotransmitter from lacrimal gland nerve endings will be measured by HPLC. The amount of IL-1beta will be determined by western blotting and ELISA. The effect of lymphocytic accumulation on lacrimal gland signaling pathways will be determined by measuring: (1) changes in [Ca2+], using Ca2+ sensitive probes; (2) changes in [cAMP] using an enzyme immunoassay (EIA) kit, and (3) changes in PKC location using immunofluorescence microscopy. Lacrimal gland secretion will be determined either in vitro, by measuring peroxidase or newly synthesized proteins secretion from acini or lobules, or in vivo by cannulating lacrimal ducts or using the Schirmer test. IL-1-ra will be given s.c. (21-day release pellets) in the capsular region of diseased animals. Serum levels of IL-1-ra will be determined by ELISA.
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