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Abstract #26106 Published in IGR 12-2
Calpain activation in experimental glaucoma
Huang W; Fileta J; Rawe I; Qu J; Grosskreutz CLInvestigative Ophthalmology and Visual Science 2010; 51: 3049-3054
PURPOSE: Glaucoma is a neurodegenerative disease in which elevated intraocular pressure (IOP) leads to progressive loss of retinal ganglion cells (RGCs) and blindness. Calcium dyshomeostasis has been suggested to play a role in the pathologic events that lead to RGC loss, though the details of these events are not well understood. Calcium-induced activation of calpain has been shown to contribute to neuronal death in a wide variety of neurodegenerative diseases. The authors hypothesize that similar events occur in glaucoma. METHODS: The authors used a well-established rat model of experimental glaucoma. Retinal tissues were harvested after 5 or 10 days of elevated IOP and were subjected to immunoblot analysis, immunoprecipitation, and MALDI-ProTOF/MS peptide fingerprint mapping. Immunohistochemistry was used to localize calpain activation. RESULTS: The authors present four independent lines of evidence that calpain is activated in experimental glaucoma. First, they showed that a 55-kDa autocatalytic active form of calpain is detected on immunoblot analysis. Second, they demonstrated the cleavage of two well-established calpain substrates, spectrin and calcineurin, only in eyes with elevated IOP. Third, they used MALDI-ProTOF to analyze cleaved calcineurin and immunoblot analysis of spectrin cleavage products and showed that both substrates were cleaved by calpain in experimental glaucoma. Fourth, they used immunohistochemistry to show that calpain-mediated spectrin cleavage occurs in RGCs under conditions of elevated IOP. CONCLUSIONS: These data support the hypothesis that calpain is activated under conditions of elevated intraocular pressure and provide further details of the pathologic events leading to RGC loss in glaucoma.
Howe Laboratory of Ophthalmology, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA.
Classification:
3.6 Cellular biology (Part of: 3 Laboratory methods)
3.3 Immunohistochemistry (Part of: 3 Laboratory methods)
3.9 Pathophysiology (Part of: 3 Laboratory methods)
5.1 Rodent (Part of: 5 Experimental glaucoma; animal models)
