Abstract
Purpose: :
Mice deficient in Bestrophin-2 (Best2) exhibit a decreased IOP despite an increase in aqueous flow. In the mouse we have found mBest2 is expressed in nonpigmented epithelia (NPE) despite a prior report indicating that Best2 is expressed in the RPE. Here we examined the distribution of hBest2 in the human eye.
Methods: :
We generated a rabbit anti-human polyclonal antiserum recognizing hBest2. That antisera (GA3512) was affinity purified and compared to commercially available anti-hBest2 polyclonal antisera. Antibody specificity was determined by immunofluorescence (IF) staining and Western blot of lysates from HEK293 cells transected with hBest2, mBest2, hBest1, mBest1, hBest3, and mBest3. To determine where in the human eye hBest2 is expressed, RT-PCR was used to determine if Best2 mRNA is expressed in human RPE or ciliary body. Lysates of human ciliary body or RPE were probed for hBest1 and hBest2 expression using immunoprecipitation (IP). The localization of hBest2 was confirmed using IF staining of human donor eyes.
Results: :
The anti-hBest-2 antibodies tested were all specific to hBest2. In the human eye, Best2 mRNA was found in the ciliary body, but not RPE. IP of hBest2 from human tissue lysates confirmed that the hBest2 protein is expressed in ciliary body and not RPE, where hBest1 is expressed. Using IF staining we found that hBest2 is localized to the NPE and appears to be localized to the basolateral surface of the cells.
Conclusions: :
Bestrophin-2 is exclusively expressed in NPE cells in human and mouse eyes. Combined with the low IOP phenotype of Best2 deficient mice, this implies that Best2 plays an important role in regulating aqueous humor dynamics.
Keywords: ciliary body • retinal pigment epithelium • immunohistochemistry