April 2010
Volume 51, Issue 13
ARVO Annual Meeting Abstract  |   April 2010
MAPK Signaling in the Angiotensin II-Mediated MMP-2 Activity in Human Retinal Pigment Epithelial Cells
Author Affiliations & Notes
  • O. Alcazar
    Ophthalmology, Bascom Palmer Eye Institute, Miami, Florida
  • M. Pons
    Ophthalmology, Bascom Palmer Eye Institute, Miami, Florida
  • M. E. Marin-Castano
    Ophthalmology, Bascom Palmer Eye Institute, Miami, Florida
  • Footnotes
    Commercial Relationships  O. Alcazar, None; M. Pons, None; M.E. Marin-Castano, None.
  • Footnotes
    Support  R01-EY015249-01A1 and an unrestricted grant by Research to Prevent Blindness P30-EY14801
Investigative Ophthalmology & Visual Science April 2010, Vol.51, 6158. doi:
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      O. Alcazar, M. Pons, M. E. Marin-Castano; MAPK Signaling in the Angiotensin II-Mediated MMP-2 Activity in Human Retinal Pigment Epithelial Cells. Invest. Ophthalmol. Vis. Sci. 2010;51(13):6158.

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      © ARVO (1962-2015); The Authors (2016-present)

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Purpose: : Accumulation of extracellular molecules under the retinal pigment epithelium has been previously observed in eyes with age-related macular degeneration (AMD) and may play a role in the pathogenesis of AMD. Clinical studies have revealed hypertension (HTN) as a systemic risk factor and Angiotensin II (Ang II) as the most important hormone associated with HTN. Our laboratory has previously shown that Ang II increases MMP-2 activity in vivo and in vitro. In the present study, we aim to explore the regulation of MAPK signaling by AngII in ARPE-19 cells, and the potential signaling connection between AngII stimulation and its well characterized effect of increasing MMP-2 activity.

Methods: : ARPE-19 cells were cultured to semiconfluent or confluence and the medium was first deprived of phenol red and then serum reduced. Cells were stimulated with Ang II for either 5 min (phosphorylation analyses) or 24 h, and further collected for protein determination. Western blot, cytoimmunostaining and zymography analyses were performed. Gene expression silencing experiments were evaluated 48 h after transient transfection with siRNA.

Results: : Immunocytochemistry and Western blot analyses showed that stimulation with AngII increased both Erk(1/2) and p38 MAPK phosphorylation while JNK phosphorylation remained unaffected. Regulation of Erk(1/2) and p38 MAPK phosphorylation by Ang II was dose-dependent and abolished in the presence of candesartan, which is an AngII Type 1 (AT1) receptor blocker. Interestingly, incubation of RPE cells with the Erk(1/2) upstream kinase MEK inhibitor PD98059 and/or the p38MAPK inhibitor SB203580 blunted the increase of MMP-2 activity induced by AngII. Moreover, using specific siRNA to decrease the expression level of Erk(1/2) and/or p38MAPK showed a concomitant decrease in the Ang II ability to stimulate the MMP-2 activity.

Conclusions: : Our study suggests that intracellular activation of Erk(1/2) and p38 MAPK signaling may be necessary for Ang II to induce an increase in MMP-2 activity in ARPE-19 cells. This effect seems to be mediated by the AT1 receptor. Further investigation is necessary to evaluate potential crosstalk between both signaling pathways.

Keywords: retinal pigment epithelium • signal transduction • age-related macular degeneration 

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