Abstract
Abstract: :
Purpose: Concentrations of TGFß are elevated in the aqueous humor of primary open angle glaucoma (POAG) patients. The exact role of TGFß on human trabecular meshwork (HTM) is unknown. This study investigated both gene and protein expression changes caused by the effects of TGFß1 and TGFß2 on HTM cells. Methods: Cultures of HTM cells were established from five donors and were treated for 72 hours with 1 ng/ml of either activated hrTGFß1, hrTGFß2, or vehicle alone. The mRNA was analyzed by Affymetrix gene microarrays and proteomic analysis was done with 2D gel electrophoresis. The gene expression profile was analyzed by using Affymetrix microarray software suite version 5.0 and changes were confirmed by real–time PCR. The 2D gel images were analyzed by using Nonlinear Dynamics Progenesis software and spots were identified by MALDI–TOF mass spectrometry. Results: The data showed that TGFß1 and TGFß2 had similar effects on HTM cells, however, TGFß1 had a greater impact. Of all genes increasing two–fold or more (87 in TGFß1, 21 in TGFß2), around 30% (23) with TGFß1 and 46% (10) with TGFß2 were associated with extracellular components (examples: versican, collagen 4, fibronectin, OSF2, matrilin 3 and fibrillin 2), and 12% (10) with TGFß1 and 16% (4) with TGFß2 were related to structural components (examples: tropomyosin alpha, actin). While of all genes decreasing two–fold or more (53 in TGFß1, 2 in TGFß2), 22% (11) with TGFß1 was asscociated with oxidoreductase activity (examples: phosphogluconate dehydrogenase, NADPH quinone dehydrogenase 1, aldo–keto reductase family members and myxoid liposarcoma associated protein 4). Another gene CDT6 highly expressed in HTM was tremendously upregulated when treated with TGFß, the function of this gene is being investigated. Of the 76 proteins identified by proteomic analysis, 5 upregulated (tropomyosin alpha, protein disulfied isomerase, calumenin, transgelin 2(SM22alpha) and leprecan) and 4 downregulated proteins (thioredoxin reductase 1, aldose reductase, G6PD and SOD), which were related to either extracelluar, molecular structural or oxidoreductase activity , had similar gene expression changes identified by microarray analysis. Conclusions: The increased expression of mRNAs associated with extracellullar matrix and structural proteins would be consistent with decreasing outflow facility. The downregulated oxireductase activity would cause redox changes in HTM cells. This study utilizing both proteomic and gene microarray analyses should provide an new insight into the effects of TGFß on HTM cells and offers a new approach in understanding the pathogenesis of POAG.
Keywords: trabecular meshwork • gene microarray • proteomics