Temple Times Online Edition
    MAY 25, 2006
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Promising cell protein may play role in infection and dry eye, researchers at Penn and Temple find

Photo by Joseph V. Labolito/University Photography
Mina Massaro-Giordano (left) of the University of Pennsylvania’s Scheie Eye Institute and Marcella Macaluso of Temple’s Sbarro Institute for Cancer Research have discovered a protein found in the tissue covering the eye may have future clinical implications in various pathologies of the ocular surface such as eye infection or dry eye.

Plasminogen Activator Inhibitor Type 2 (PAI-2), a protein found in various cell types including the skin, has been discovered in the tissue covering the eye and may have future clinical implications in various pathologies of the ocular surface such as eye infection or dry eye, according to researchers at the University of Pennsylvania and Temple.

The researchers were led by Mina Massaro-Giordano, of the University of Pennsylvania's Scheie Eye Institute, and Marcella Macaluso, of Temple's Sbarro Institute for Cancer Research.

PAI-2, in either extracellular or secreted form, is a multifunctional protein that plays a role in cell differentiation, in prevention of programmed cell death, in the regulation of cell proliferation, in the inhibition of microbial proteinases and in the protection against stromal degradation.

High levels of the PAI-2 protein are associated with a good prognosis in breast cancer, small cell lung cancer, ovarian cancer, and inhibition of metastasis (the spreading of a cancer cells from one organ or tissue to another). PAI-2 also plays a role in inflammation on the surface of the eye.

In their study, the Penn and Temple researchers demonstrated for the first time an interaction between PAI-2 and the protein of the tumor-suppressing gene Rb2/p130 (pRb2/p130) in the nucleus of the epithelial cells in the cornea and conjunctiva, the membrane that covers the eye's outer surface.

According to the researchers, this interaction among pRb2/p130, PAI-2 and chromatin modeling enzymes may affect how PAI-2 is expressed.

"There is a different expression of the protein between the epithelium of the cornea and conjunctiva cells," said Massaro-Giordano, an assistant professor of ophthalmology, cataract and refractive surgery at Scheie. "This may help us understand the molecular mechanisms that dictate the different expression profiles of PAI-2 in human corneal and conjunctival epithelial cells."

Their findings were published online in the January 2006 issue of Cell Death and Differentiation (www.nature.com/cdd).

The researchers also recently presented their findings at the annual meeting of the Association for Research in Vision and Ophthalmology in Florida, which was attended by more than 10,000 researchers.

The study, which was done in collaboration with Italy's University of Siena, was funded by the National Institutes of Health and the Sbarro Health Research Organization.

- By Preston M. Moretz