Cathepsin B in the rat eye.
BACKGROUND
Cathepsin B is a mammalian cysteine protease. The enzyme has been suggested to participate in the patophysiological processes of keratoconus as well as in the corneal response to infectious agents. This study describes the localization of cathepsin B in the rat eye.


METHODS
Cathepsin B was identified in rat ocular tissues by Western blotting and immunohistochemistry. Cathepsin B mRNA levels were analyzed in the tissues by quantitative real-time cDNA amplification (QRT-PCR).


RESULTS
Cathepsin B is present in the epithelium, in stromal cells and in the endothelium of the cornea. It is also present in the epithelium lining the ciliary processes, in occasional stromal cells in the iris, in the anterior subcapsular lens epithelium and in various cell types in the retina. At all locations cathepsin B is present in cytoplasmic granules, presumably lysosomes. QRT-PCR analysis detected cathepsin B mRNA in all these tissues in amounts correlating to the immunodetection results, suggesting that the enzyme detected is locally produced.


CONCLUSIONS
Cathepsin B is present in several tissues and cell types throughout the rat eye. It is localized to cytoplasmic granules, presumably lysosomes. Our results suggest that it is probably also produced in the same cell types.
Wassélius
Johan
J
Department of Ophthalmology, University of Lund, 221 85, Lund, Sweden. johan.wasselius@oft.lu.se
Wallin
Hanna
H
Abrahamson
Magnus
M
Ehinger
Berndt
B
D000818:Animals; D015153:Blotting, Western; D002401:Cathepsin B / Q000235:genetics / Q000378:metabolism*; D003199:Computer Systems; D005123:Eye / Q000378:metabolism*; D007150:Immunohistochemistry; D018613:Microscopy, Confocal; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats / Q000378:metabolism*; D014018:Tissue Distribution
D012333:RNA, Messenger; D002401:Cathepsin B