Beta-amyloid protein protein precursor expression in lacrimal glands and tear fluid

摘要: Purpose. Proteases in tear fluid play important roles the regulation of corneal wound healing. Inhibitors proteolytic activity are major modulators associated events. Although it is known that various enzyme inhibitors exist fluid, not whether certain isoforms /?-amyloid protein precursor (/?-APP), a potent inhibitor serine proteases, present fluid. The purpose this study was to investigate (3APP can be detected human and, if so, determine isoform composition and cellular origin. Methods. Tear collected from healthy volunteers. /3-APP identified characterized by immunoblotting using antibodies specific for domains /3-APP. further ion exchange chromatography. Expression /5-APP gene studied situ hybridization RNA-RNA solution assay. Results. with protease inhibitory properties all samples Immunologic analysis revealed had been processed proteolytically before secretion. Gene expression studies showed /?-APP expressed lacrimal glands, particularly acinar cells. transcript almost exclusively corresponded containing insert. Conclusions. glands subsequently secreted into Because bulk contained insert, authors propose an regulator proteolysis possibly plays role events This suggests novel physiological function addition those previously described—regulation blood coagulation cell growth. Invest Ophthalmol Vis Sci. 1996;37:2585-2593.