Expression of Procollagen C Proteinase Enhancer Proteins in Trabecular Cells and Tissues

Primary open angle glaucoma (POAG) is the most common form of glaucoma. Ocular hypertension is a major risk factor for POAG and is caused by increased aqueous humor (AH) outflow resistance in the trabecular meshwork (TM). Increased extracellular matrix (ECM) deposition within the TM is correlated with ocular hypertension. Transforming Growth Factor beta 2 (TGFb2) levels are elevated in the AH and TM of POAG patients, and TGFb2 increases ECM protein expression, aqueous outflow resistance, and intraocular pressure (IOP). Recently, TGFβ2 was found to induce bone morphogenetic protein 1 (BMP1) expression in TM cells suggesting that BMP1 activity might be involved in glaucoma pathogenesis. Procollagen C proteinase enhancers (PCOLCE 1 and PCOLCE 2) regulate BMP1 activity. Therefore, PCOLCE1 and PCOLCE2 may play an important role(s) in regulating ECM structural changes in the TM, and contribute to AH outflow resistance and elevated IOP in glaucoma. The purpose of this study was to determine if human TM cells and tissues express PCOLCE1 and PCOLCE2 and whether TGFb2 induces their expression. This is the first documentation that PCOLCE1 and PCOLCE2 are expressed in TM cells and tissues and that TGFb2 does induce expression of PCOLCE1.