SPARC modulates expression of extracellular matrix genes in human trabecular meshwork cells

Purpose: To investigate the effects of secreted protein acidic and rich in cysteine (SPARC) on the expression of components of the extracellular matrix (ECM) in cultured human trabecular meshwork (TM) cells. Methods: Cultured human trabecular cells were transfected with small interfering RNAs (siRNAs) specific for the human SPARC gene. Protein and mRNA expressions of fibronectin (FN) and the alpha 1chains of collagen I and collagen III were quantified. Results: After silencing of the SPARC gene by transfection of cells with SPARC siRNA, the expression of COL1A1 and COL3A1 mRNAs and proteins was significantly enhanced, as compared to that in the control group (all, p < 0.001). In contrast, SPARC siRNA significantly reduced the expression of FN and SPARC mRNAs and FN protein, as compared to that in the control group (all, p < 0.001.). Conclusions: SPARC modulates the expression of several ECM genes in cultured human TM cells.