RPTP-σ increases pro-MMP activity in a trabecular meshwork cell line following oxidative stress conditions
Reviewed by Wai Siene Ng

This study aims to outline the role of phosphatases in the aqueous drainage system by overexpressing receptor tyrosine phosphatase sigma (RPTP-σ) in a human normal trabecular meshwork cell line and describing its effect on subtypes of matrix metalloproteinases (MMP) and viability under oxidative stress conditions. RPTP-σ overexpression was achieved through lipofection with GFP tagged pcDNA3.2/Zeo(+) and RPTP-σ sequence. Transfection was checked with fluorescence-activated cell sorting, Western Blot and immunofluorescence. Oxidative stress was applied via hydrogen peroxide and inhibition of RPTP-σ activity was achieved using PTP Inhibitor IV. Transfection efficiency was high at 126.5% higher activity in comparison to normal trabecular meshwork cells, and was located in the cytosol of the cells. Transfected cells did not show any difference in viability post oxidative stress in comparison to normal trabecular meshwork cells. RPTP-σ inhibition attenuated the activity of pro-MMP-9 by 48%, active MMP-9 by 35% and pro-MMP2 by 78%. Overall, this study successfully highlights phosphatases as a novel pathway linking MMP changes to trabecular meshwork cells which may be new targets for glaucoma intervention.

Receptor protein tyrosine phosphotase sigma (RPTP-σ) increases pro-MMP activity in a trabecular meshwork cell line following oxidative stress conditions.
Zaiden M, Beit-Yannai E.
INVESTIGATIVE OPHTHALMOLOGY AND VISUAL SCIENCE
2015;56:5720-30.