Regulated secretion of complement factor H by RPE and its role in RPE migration

  • Yeong Hoon Kim
  • Shikun He
  • Satoru Kase
  • Mizuki Kitamura
  • Stephen J. Ryan
  • David R. Hinton
Basic Science

DOI: 10.1007/s00417-009-1049-y

Cite this article as:
Kim, Y.H., He, S., Kase, S. et al. Graefes Arch Clin Exp Ophthalmol (2009) 247: 651. doi:10.1007/s00417-009-1049-y

Abstract

Background

Variants in the gene for complement factor H (CFH) have been implicated as a major risk factor for the development of age-related macular degeneration (AMD). Little is known, however, about the factors regulating local expression and secretion of CFH by retinal pigment epithelial cells (RPE).

Methods

Cultured human early passage RPE cells, highly differentiated, polarized human RPE cultures, and bovine RPE explants were incubated in the presence or absence of recombinant human or bovine interferon-γ (IFN-γ; 25 ng/ml). CFH expression in cell lysates, and secretion into culture supernatants were examined by Western blot. CHF expression and localization was analyzed by confocal microscopy. Migration assay was performed in a modified Boyden chamber with early passage human RPE cells after stimulation with recombinant CFH protein (1–100 ng/ml).

Results

CFH was expressed in the cell lysates of RPE cells, and this expression was significantly upregulated by IFN-γ. Immunoreactivity for CFH was detected in RPE cells of bovine explants and highly differentiated human RPE monolayers, and the level of immunoreactivity increased after IFN-γ stimulation. Confocal microscopy revealed that CFH was predominantly localized in the apical cytoplasm of polarized human RPE. Western blot confirmed that IFN-γ increased CFH secretion into RPE supernatants. Dose-dependent RPE cell chemotactic migration was induced by CFH.

Conclusion

IFN-γ promotes CFH expression in the apical compartment of RPE cells and increases secretion of CFH into RPE culture supernatants. Furthermore, CFH promotes chemotactic migration of RPE. This study suggests that interactions between CFH and IFN-γ have the potential to play a role in the pathogenesis of AMD.

Keywords

AMD Complement factor H Migration Retinal pigment epithelium Interferon-γ 

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Yeong Hoon Kim
    • 1
    • 2
  • Shikun He
    • 1
    • 2
    • 3
  • Satoru Kase
    • 1
  • Mizuki Kitamura
    • 1
  • Stephen J. Ryan
    • 1
    • 2
  • David R. Hinton
    • 1
    • 2
    • 3
  1. 1.Doheny Eye InstituteKeck School of Medicine of the University of Southern CaliforniaLos AngelesUSA
  2. 2.Department of OphthalmologyKeck School of Medicine of the University of Southern CaliforniaLos AngelesUSA
  3. 3.Department of PathologyKeck School of Medicine of the University of Southern CaliforniaLos AngelesUSA

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