Complement factor H: spatial and temporal expression and localization in the eye.
OBJECTIVE
Complement factor H (CFH) is a component of the mammalian complement system, which regulates the alternative pathway of complement activation and protects the host cell from inappropriate complement activation. CFH is a key regulator of innate immunity, and CFH deficiency leads to membranoproliferative glomerulonephritis type II. A variation in human CFH, Y402H, has been shown to be associated with an increased risk for age-related macular degeneration. The authors describe studies on the spatial and temporal expression of the CFH gene and localization of this protein in ocular tissues to gain insight into its role in the eye.


METHODS
CFH expression in human and mouse tissues was studied by quantitative RT-PCR and Western blot analysis, and localization of CFH was studied by immunohistochemical analysis followed by fluorescence microscopy.


RESULTS
In human and mouse, CFH expression was found to be similar to the highest level of expression in the liver. In ocular tissue, CFH was detected in the distalmost optic nerve (3 mm) cut from the scleral surface of the eyeball, sclera, RPE-choroid, retina, lens, and ciliary body. In mouse, Cfh expression was observed from early embryonic stages, and in the eye its expression increased with age.


CONCLUSIONS
A significant level of CFH expression is maintained in different ocular tissues during development and aging. Sustained high levels of CFH expression in eye tissues suggest that this protein may play a role in protecting these tissues from indiscriminate complement activation and inflammatory insult.
Mandal
Md Nawajes A
MN
Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan 48105, USA.
Ayyagari
Radha
R
D000368:Aged; D000375:Aging / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D017242:Complement Factor H / Q000235:genetics* / Q000378:metabolism; D005123:Eye / Q000196:embryology / Q000378:metabolism*; D015870:Gene Expression / Q000502:physiology*; D006801:Humans; D008099:Liver / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014018:Tissue Distribution
C493495:CFH protein, human; D017242:Complement Factor H