HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Morand, S. Articles by Schorderet, D. F. Search for Related Content PubMed PubMed Citation Articles by Morand, S. Articles by Schorderet, D. F.

Induction of Apoptosis in Human Corneal and HeLa Cells by Mutated BIGH3

¹From the Division of Medical Genetics, the ²Unit of Oculogenetics, the ³Jules Gonin Eye Hospital, and the ⁴Institute for Research in Ophthalmology, Sion, Switzerland, Department of Ophthalmology, University of Lausanne, Lausanne, Switzerland.

PURPOSE. To determine the effects of overexpression of mutated BIGH3 in HeLa and human corneal epithelial (HCE) cells.

METHODS. Six mutations known to be responsible for autosomal dominant corneal dystrophies linked to chromosome 5 were generated in a BIGH3 expression vector and transfected in HeLa and HCE cells. The expression and secretion of the various BIGH3-EGFP fusion proteins were measured by Western blot analysis. Apoptotic cells were identified by Hoechst/propidium iodide and annexin V staining. Lactate dehydrogenase (LDH) activity was measured in the medium of transfected cells. Truncated BIGH3 protein and site-specific mutations were generated to determine the exact region that mediated apoptosis.

RESULT. The overexpressed BIGH3 fusion protein was secreted regardless of its mutation status and was clearly observed in the culture medium. Overexpression of mutated BIGH3 induced apoptosis in both cell lines through activation of caspase-3. Although all the disease-causing mutations tested in this experiment induced apoptosis, the strongest effect was observed with the R124C and R555W mutations. Overexpression of a carboxyl-truncated BIGH3 protein did not induce apoptosis, suggesting that a region located in the C-terminal domain was necessary to mediate cell death. In addition, mutation of the Pro-Asp-Ile (PDI) site at 616-618 was sufficient to prevent induction of apoptosis.

CONCLUSIONS. Overexpression of mutated BIGH3 induces apoptosis in HeLa and HCE cells through activation of a pathway that uses the PDI domain of the fourth internal Fas domain and activation of caspase-3. Because DI is a known site of interaction with 3ß1 integrins, it suggests that integrins play a role in mediating apoptosis in the system used in the current study. This work suggests that apoptosis is a key element in the pathophysiology of BIGH3-related corneal dystrophies.

This article has been cited by other articles:

				B. Stix, M. Leber, P. Bingemer, C. Gross, J. Ruschoff, M. Fandrich, D. F. Schorderet, C. K. Vorwerk, M. Zacharias, A. Roessner, et al. Hereditary Lattice Corneal Dystrophy Is Associated with Corneal Amyloid Deposits Enclosing C-Terminal Fragments of Keratoepithelin Invest. Ophthalmol. Vis. Sci., April 1, 2005; 46(4): 1133 - 1139. [Abstract] [Full Text] [PDF]