Abstract
Purpose: :
The stress–related protein myocilin, MYCO, and the hyaluronans receptor, CD44, are both being investigated in a colony of Beagles with inherited spontaneous, hypertensive glaucoma. We have examined the localization of MYOC and CD44 together in the normal and glaucomatous eyes by confocal co–immuno–histochemistry.
Methods: :
Paraffin–embedded specimens from the anterior uveas of 7 Beagles with inherited glaucoma (3 to10–yrs–old) and age–matched normal Beagles were sectioned and incubated with a mixture of primary antibodies: rabbit polyclonal anti–human MYOC IgG (Santa Cruz Biotechnology) combined with monoclonal anti–human CD44H IgG (R & D Systems, Inc.), and diluted with 3% BSA blocker for 1 hour at RT. Specimens were successively washed and incubated with a mixture of secondary antibodies: goat anti–rabbit Texas Red and goat anti–mouse Alexaflour488 (green)(both by Molecular Probes), diluted with Tris buffer for 1 hr at RT. Labeled specimens were analyzed by confocal microscopy.
Results: :
Within the ciliary body (CB) of the normal specimens, cells of the nonpigmented epithelium (NPE) of the CB processes stained diffusely for MYOC and CD44 within their cytoplasm. Within the CB processes of moderately glaucomatous specimens, areas of the NPE reacted more positively than age–matched normals with specific MYOC–positive regions within the cytoplasm of some cells. Within the CB of advanced glaucomatous specimens, co–localization increased markedly due to mostly changes in CD44. Trabecular meshwork cells were consistently co–labeled as well as the sclera adjacent to the angular aqueous plexus in all normal and glaucomatous specimens. In advanced glaucoma specimens, greater intensity of CD44 staining was observed within the trabeculae and adjacent scleral collagen.
Conclusions: :
Co–immunolocalization of MYOC and CD44 was successfully observed for the first time in normal and glaucomatous eyes. It was interesting to observe that both proteins co–localized to the same tissues and often to the same regions of the cell. Both MYOC and CD44 are involved in the development and progression of this canine form of POAG as changes in their activity appear to occur within the aqueous humor outflow pathway of individuals with spontaneous glaucoma with CD44 having progressed more substantially than MYOC in the advanced stages of this disease.
Keywords: microscopy: confocal/tunneling • immunohistochemistry • ciliary body