title: Interaction of complement factor h and fibulin3 in age-related macular degeneration.
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.
authors.affiliation: Section on Molecular Structure and Functional Genomics, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: M Keith
authors.initials: MK
authors.lastname: Wyatt
authors.forename: Jen-Yue
authors.initials: JY
authors.lastname: Tsai
authors.forename: Sanghamitra
authors.initials: S
authors.lastname: Mishra
authors.forename: Maria
authors.initials: M
authors.lastname: Campos
authors.forename: Cynthia
authors.initials: C
authors.lastname: Jaworski
authors.forename: Robert N
authors.initials: RN
authors.lastname: Fariss
authors.forename: Steven L
authors.initials: SL
authors.lastname: Bernstein
authors.forename: Graeme
authors.initials: G
authors.lastname: Wistow
mesh_terms: D000368:Aged; D002478:Cells, Cultured; D002829:Choroid / Q000378:metabolism / Q000473:pathology; D017242:Complement Factor H / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D047468:Immunoprecipitation / Q000379:methods; D008268:Macular Degeneration / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011994:Recombinant Proteins / Q000378:metabolism; D055213:Retinal Pigment Epithelium / Q000378:metabolism / Q000473:pathology
chemical_list: C119630:EFEMP1 protein, human; D016326:Extracellular Matrix Proteins; D011994:Recombinant Proteins; D017242:Complement Factor H