Changes in extracellular matrix gene and protein expressions in human trabecular meshwork cells in response to mechanical fluid flow stimulation

Abstract

PurposeTo investigate the changes in extracellular matrix (ECM) gene and protein expressions in human trabecular meshwork (HTM) cells in response to mechanical fluid flow stimulation.\n\nMethodsHTM cells were cultured on a glass plate and exposed to shear stress (0, 0.2, and 1.0 dyne/cm2) for 12 hours. Changes in gene expressions were evaluated using microarray analysis. The representative genes related to ECM metabolism underwent real-time reverse-transcriptase polymerase chain reaction. Fibronectin (FN) and collagen (COL) IV levels in the supernatant were evaluated using immunoassays. Rho-associated coiled-coil-containing protein kinase (ROCK) activity also was investigated.\n\nResultsAfter stimulation, transforming growth factor {beta}2 mRNA levels were significantly (p < 0.01) lower than that of the static control (0 dyne/cm2 for 12 hours). Matrix metalloproteinase 2 mRNA levels were significantly (p < 0.05) higher than the static control. COL type 1 alpha 2 mRNA, COL type 4 alpha 2 mRNA, and COL type 6 alpha 1 mRNA levels were significantly (p < 0.05, < 0.01, and < 0.05, respectively) higher than the static control. The mean {+/-} standard deviation FN levels (ng/mL) in the supernatant after stimulation (0, 0.2, 1.0 dyne/cm2) were 193.7 {+/-} 7.6, 51.5 {+/-} 21.8, and 34.9 {+/-} 23.6, respectively (p < 0.01). The FN and COL IV levels and ROCK activity were significantly (p < 0.01 and < 0.05, respectively) lower than the static control.\n\nConclusionsChanges in gene and protein expressions related to ECM metabolism occurred in HTM cells after stimulation. Specifically, the suppression of FN and COL IV production might explain the importance of mechanical fluid flow stimulation on maintenance of the normal aqueous humor outflow.