A Comparison Of Protein Expression In Trabecular Meshwork And Normal And Primary Open Angle Glaucoma Schlemm’s Canal Endothelial Cells

Abstract

Abstract: : Purpose: Dysfunction of trabecular meshwork (TM) or Schlemm’s canal endothelial (SCE) cells is likely the causative mechanism in the development of primary open angle glaucoma (POAG). The aim of this study is to compare and contrast the in vitro protein expression in TM cells from normal eyes, and SCE cells from normal and POAG eyes. Methods: TM (normal) and SCE (normal and POAG) cells were isolated from cadaver eyes harvested within 48 hours of death. TM cells were dissected from the anterior chamber angle and cultured in media supplemented with fibroblast growth factor. SCE cells were isolated by threading of Schlemm’s canal with a 6–0 nylon suture. After 1 month the suture was removed and transferred to culture dishes. Once confluent, cells were lysed and protein collected for isoelectric focusing (pH 3 – pH 10) and subsequent gel electrophoresis (10–20% Tris HCl) to create 11 cm x 8 cm 2–D maps. Results: A protein band at 35 kD and isoelectric point of 8 was observed on SCE maps but was absent from TM maps. There was also a cluster of 3 bands from 14.4 – 6.5 kD and pH(I) 7–8 present in SCE maps but absent from TM maps. On glaucoma SCE map a dark band at 45 kD and pH(I) 7 was observed but was absent from normal SCE maps. Conclusion: This study has demonstrated a difference in protein expression between TM and SCE cells. In comparing normal and POAG SCE cells, the band difference at 45 kD and pH(I) 7 constitutes a possible candidate glaucoma gene for further study. Further concentrated study into this area of the map is warranted, perhaps with isoelectric focusing at pH 6 – pH 8.

Keywords: proteomics • trabecular meshwork