Activation of Rap1 inhibits NADPH oxidase-dependent ROS generation in retinal pigment epithelium and reduces choroidal neovascularization

Haibo Wang, Yanchao Jiang, Dallas Shi, Lawrence A. Quilliam, Magdalena Chrzanowska-Wodnicka, Erika S. Wittchen, Dean Y. Li, M. Elizabeth Hartnett

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

Activation of Rap1 GTPase can improve the integrity of the barrier of the retina pigment epithelium (RPE) and reduce choroidal neovascularization (CNV). Inhibition of NADPH oxidase activation also reduces CNV. We hypothesize that Rap1 inhibits NADPH oxidase-generated ROS and thereby reduces CNV formation. Using a murine model of laser-induced CNV, we determined that reduced Rap1 activity in RPE/choroid occurred with CNV formation and that activation of Rap1 by 2′-O-Me-cAMP (8CPT)-reduced laser-induced CNV via inhibiting NADPH oxidase-generated ROS. In RPE, inhibition of Rap1 by Rap1 GTPase-activating protein (Rap1GAP) increased ROS generation, whereas activation of Rap1 by 8CPT reduced ROS by interfering with the assembly of NADPH oxidase membrane subunit p22phox with NOX4 or cytoplasmic subunit p47phox. Activation of NADPH oxidase with Rap1GAP reduced RPE barrier integrity via cadherin phosphorylation and facilitated choroidal EC migration across the RPE monolayer. Rap1GAPinduced ROS generation was inhibited by active Rap1a, but not Rap1b, and activation of Rap1a by 8CPT in Rap1b-/- mice reduced laser-induced CNV, in correlation with decreased ROS generation in RPE/choroid. These findings provide evidence that active Rap1 reduces CNV by interfering with the assembly of NADPH oxidase subunits and increasing the integrity of the RPE barrier.

Original languageEnglish (US)
Pages (from-to)265-274
Number of pages10
JournalFASEB Journal
Volume28
Issue number1
DOIs
StatePublished - Jan 2014

Keywords

  • Barrier integrity
  • GTPase-activating proteins
  • NOX4
  • P22phox
  • P47phox

ASJC Scopus subject areas

  • Biochemistry
  • Biotechnology
  • Genetics
  • Molecular Biology
  • Medicine(all)

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