April 2011
Volume 52, Issue 14
Free
ARVO Annual Meeting Abstract  |   April 2011
Bestrophin Modulates Phagocytosis of Photoreceptors Outer Segments by Retinal Pigment Epithelial Cells
Author Affiliations & Notes
  • Shadi K. Safuri
    Ruth & Bruce Rappaport Faculty of Medicine and Rappaport Institute, Technion-Israel Institute of Technology, Haifa, Israel
  • Ido Perlman
    Ruth & Bruce Rappaport Faculty of Medicine and Rappaport Institute, Technion-Israel Institute of Technology, Haifa, Israel
  • Footnotes
    Commercial Relationships  Shadi K. Safuri, None; Ido Perlman, None
  • Footnotes
    Support  Technion V.P.R. Fund - The Edward S. Mueller Eye Research Fund
Investigative Ophthalmology & Visual Science April 2011, Vol.52, 1771. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Shadi K. Safuri, Ido Perlman; Bestrophin Modulates Phagocytosis of Photoreceptors Outer Segments by Retinal Pigment Epithelial Cells. Invest. Ophthalmol. Vis. Sci. 2011;52(14):1771.

      Download citation file:


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

      ×
  • Supplements
Abstract

Purpose: : Best vitelliform macular dystrophy (Best Disease) result from specific mutations in the bestrophin-1 gene, which is localized to the retinal pigment epithelium (RPE) cells. Despite established molecular functions, the physiological role played by the bestrophin-1 protein (Best1) in RPE cells and the mechanism of Best Disease are yet unknown. Lipofuscin accumulation suggests involvement of photoreceptors outer segments (POS) in disease pathogenesis. Accordingly, we tested the effects of Best1 mutations on the phagocytosis process of POS by RPE cells.

Methods: : Different Best1 mutations associated with distinct phenotypes were generated using site-directed mutagenesis. Verified vectors were cloned into pBABE-puro retroviral vectors and subsequently used to transduce ARPE19 cells, thus generating RPE cell lines stably expressing different variants of Best1. Monolayers of these lines were challenged with FITC labeled photoreceptor outer segment (POS) according to different protocols. Trypan blue was used to discriminate between bound and engulfed POS.

Results: : Phagocytosis of POS by RPE lines displayed saturation characteristics. Following a saturating pulse of POS, RPE lines expressing Best Disease associated mutants (R218S or E300D) displayed enhanced binding and engulfment compared to wild-type (wt). In contrast, V86M, associated with autosomal dominant vitreoretinochoroidopathy (ADVIRC), resulted in reduction in these processes. To better characterize this modulation, curves were fitted to a Michaelis-Menten model. Vmax and Km were increased in Best, but both were decreased in ADVIRC, compared to wt. Interestingly, the line expressing R47H mutant associated with adult-onset vitelliform dystrophy (AVMD) had Vmax and Km values intermediate between Best and wt variants.

Conclusions: : Best1 mutations modulate phagocytosis in a phenotype-dependent manner. The decreased affinity for POS observed in Best Disease and AVMD, and decreased maximal phagocytosis capability observed in ADVIRC, may underlie the mechanism of lipofuscin accumulation in RPE cells, characteristic of these phenotypes.

Keywords: macula/fovea • degenerations/dystrophies • retinal pigment epithelium 
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×