TGF-ß-3 Induces Different Effects from TGF-ß-1 and -2 on Cellular Metabolism and the Spatial Properties of the Human Trabecular Meshwork Cells.

To compare the effects among three TGF-ß isoforms (TGF-ß-1, TGF-ß-2, and TGF-ß-3) on the human trabecular meshwork (HTM), two-dimensional (2D) and three-dimensional (3D) cultures of commercially available certified immortalized HTM cells were used, and the following analyses were conducted: (1) trans-endothelial electrical resistance (TEER) and FITC dextran permeability measurements (2D); (2) a real-time cellular metabolic analysis (2D); (3) analysis of the physical property of the 3D HTM spheroids; and (4) an assessment of the gene expression levels of extracellular matrix (ECM) components (2D and 3D). All three TGF-ß isoforms induced a significant increase in TEER values and a relative decrease in FITC dextran permeability in the 2D-cultured HTM cells, but these effects were the most potent in the case of TGF-ß-3. The findings indicated that solutions containing 10 ng/mL of TGF-ß-1, 5 ng/mL of TGF-ß-2, and 1 ng/mL of TGF-ß-3 had nearly comparable effects on TEER measurements. However, a real-time cellular metabolic analysis of the 2D-cultured HTM cells under these concentrations revealed that TGF-3-ß induced quite different effects on the metabolic phenotype, with a decreased ATP-linked respiration, increased proton leakage, and decreased glycolytic capacity compared with TGF-ß-1 and TGF-ß-2. In addition, the concentrations of the three TGF-ß isoforms also caused diverse effects on the physical properties of 3D HTM spheroids and the mRNA expression of ECMs and their modulators, in many of which, the effects of TGF-ß-3 were markedly different from TGF-ß-1 and TGF-ß-2. The findings presented herein suggest that these diverse efficacies among the TGF-ß isoforms, especially the unique action of TGF-ß-3 toward HTM, may induce different effects within the pathogenesis of glaucoma.