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Abstract #5583 Published in IGR 2-1
Localization of myocilin/trabecular meshwork-inducible flucocorticoid response protein in the human eye
Karali A; Russell P; Stefani FH; Tamm ERInvestigative Ophthalmology and Visual Science 2000; 41: 729-740
PURPOSE: To study distribution and cellular localization of myocilin/trabecular meshwork-inducible glucocorticoid response protein (TIGR) in the human eye. METHODS: A peptide antibody against a portion of the myosin-like domain of myocilin/TIGR was developed. Different ocular tissues from three human donors were investigated by one- and two-dimensional gel electrophoresis and Western blot analysis. Immunohistochemistry was performed on 25 human eyes enucleated because of posterior choroidal melanoma and on seven normal human donor eyes. RESULTS: By Western blot analysis, a band at approximately 57 kDa was visualized in cornea, trabecular meshwork, lamina cribrosa, optic nerve, retina, iris, ciliary body, and vitreous humor. By immunohistochemistry, immunoreactivity for myocilin/TIGR was observed in cells of the corneal epi- and endothelium and extracellularly in the corneal stroma and sclera. In the trabecular meshwork, cells of the uveal and corneoscleral meshwork were stained, as was the cribriform area directly adjacent to Schlemm's canal. Positive staining was seen in cells of the ciliary epithelium, ciliary muscles, lens epithelium, and in stromal and smooth muscle cells of the iris. Throughout the entire vitreous body, fine filamentous material was positively labelled. In the retina, staining was seen along the outer surface of rods and cones, in neurons of the inner and outer nuclear layer, and in the axons of optic nerve ganglion cells. Optic nerve axons were stained in the prelaminar, laminar, and postlaminar parts of the nerve. In the region of the lamina cribrosa, astrocytes in the glial columns and cribriform plates were positively labelled. CONCLUSIONS: Myocilin/TIGR is expressed in almost every ocular tissue. Depending on the respective tissue, it is observed extra- or intracellularly. The presence of myocilin/TIGR in optic nerve axons and lamina cribrosa astrocytes indicates that the trabecular meshwork might not be the only target of abnormal myocilin/TIGR in GLCIA-linked open-angle glaucoma.
Dr. E.R. Tamm, Department of Anatomy II, University of Erlangen-Nürnberg, Universitätsstrasse 19, D-91054 Erlangen, Germany. ertamm@anatomie.uni.erlangen.de
Classification:
2.5 Meshwork (Part of: 2 Anatomical structures in glaucoma)
3.3 Immunohistochemistry (Part of: 3 Laboratory methods)
