Interaction of complement factor h and fibulin3 in age-related macular degeneration

PLoS One. 2013 Jun 28;8(6):e68088. doi: 10.1371/journal.pone.0068088. Print 2013.

Abstract

Age-related macular degeneration (AMD) is a major cause of vision loss. It is associated with development of characteristic plaque-like deposits (soft drusen) in Bruch's membrane basal to the retinal pigment epithelium (RPE). A sequence variant (Y402H) in short consensus repeat domain 7 (SCR7) of complement factor H (CFH) is associated with risk for "dry" AMD. We asked whether the eye-targeting of this disease might be related to specific interactions of CFH SCR7 with proteins expressed in the aging human RPE/choroid that could contribute to protein deposition in drusen. Yeast 2-hybrid (Y2H) screens of a retinal pigment epithelium/choroid library derived from aged donors using CFH SCR7 baits detected an interaction with EFEMP1/Fibulin 3 (Fib3), which is the locus for an inherited macular degeneration and also accumulates basal to macular RPE in AMD. The CFH/Fib3 interaction was validated by co-immunoprecipitation of native proteins. Quantitative Y2H and ELISA assays with different recombinant protein constructs both demonstrated higher affinity for Fib3 for the disease-related CFH 402H variant. Immuno-labeling revealed colocalization of CFH and Fib3 in globular deposits within cholesterol-rich domains in soft drusen in two AMD donors homozygous for CFH 402H (H/H). This pattern of labeling was quite distinct from those seen in examples of eyes with Y/Y and H/Y genotypes. The CFH 402H/Fib3 interaction could contribute to the development of pathological aggregates in soft drusen in some patients and as such might provide a target for therapeutic intervention in some forms of AMD.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Aged
  • Cells, Cultured
  • Choroid / metabolism
  • Choroid / pathology
  • Complement Factor H / metabolism*
  • Extracellular Matrix Proteins / metabolism*
  • Female
  • Humans
  • Immunoprecipitation / methods
  • Macular Degeneration / metabolism*
  • Macular Degeneration / pathology
  • Male
  • Middle Aged
  • Recombinant Proteins / metabolism
  • Retinal Pigment Epithelium / metabolism
  • Retinal Pigment Epithelium / pathology

Substances

  • EFEMP1 protein, human
  • Extracellular Matrix Proteins
  • Recombinant Proteins
  • Complement Factor H