THIOREDOXIN FAMILY PROTEINS PLAY A KEY ROLE IN RPE CELL PROLIFERATION, MIGRATION AND DIFFERENTIATION

MARIANA HOLUBIEC , EVA-MARIA HANSCHMANN, LISA FALK , CHRISTOPHER HORST LILLIG , FRANCISCO CAPANI

Heidelberg

Congreso; 2nd Symposium of the SPP 1710 and the Study Group Redox Biology of the German Society for Biochemistry and Molecular Biology (GBM), 22-23 September 2014, Heidelberg, Germany; 2014

Introduction The retina is a tissue that undergoes high levels of stress due to its exposure to elevated oxygen levels and different light intensities (1). Retinal pigment epithelium (RPE) cells are located near the choroidal capillaries, making them particularly susceptible to ischemia or hypoxia (2). A hypoxic event leads to an overall diminished cellular antioxidant capacity and causes several damages to cellular components (3). Thioredoxin family proteins (TRXS) are key enzymes in cellular redox regulation (4) and we propose that they play a particularly important role in RPE cells subjected to hypoxic conditions in pathologies such as age-related macular degeneration (AMD) or retinopathy of prematurity. Methods MTT assay, ELISA, Migration assay, Immunofluorescence staining, Confocal microscopy and Western blot analysis were used to determine the effects of specific knock downs of different TRX proteins (Grx1, Grx2, Trx1, Trx2 and Nrx) in ARPE-19 cells exposed to a hypoxic event and later reoxygenation stages. Histological analysis was performed in order to determine changes in retinal tissue obtained from male Sprague-Dawley rats subjected to a murine model of Hypoxia Ischemia. Results Grx1 knockdown caused a decrease in cellular proliferation in ARPE-19 cells. The hypoxic event did not lead to significant changes in cellular viability, nor did the reoxygenation in wild type or knockdown cells. However, hypoxia and later reoxygenation led to migration alterations, morphological changes, observed in the actin cytoskeleton, and to changes in cell polarization and differentiation, depending on the redoxin expression. Conclusions The different members of the TRXS play a most important role in proliferation, polarization, differentiation and migration of RPE cells. These finding are necessary to elucidate the biochemical mechanisms underlying the role of the TRXS in the retina and to improve the understanding of different physiological and pathological conditions.