Effects of Sp1 overexpression on cultured human corneal stromal cells.

Xiang Shen; Jeong-Seok Park; Ye Qiu; Sugar, Joel; Yue, Beatrice Y. J. T.

Sp1, a transcription factor, is upregulated in keratoconus, a cornea-thinning disease. Keratoconus corneas have also been shown to contain increased levels of degradative enzymes such as cathepsin B and decreased proteinase inhibitors such as α1-proteinase inhibitor (α1-PI). We transfected cultured human corneal stromal cells to overexpress Sp1. The resulting effects on cathepsin B and α1-PI levels as well as the cellular proliferative and apoptotic activities were examined by Western blotting and cytochemical staining. It was found that the Sp1 transfected cells contained a greater amount of cathepsin B than did mock transfected controls. The activity of cathepsin B was also increased. By contrast, the protein level of α1-PI was lowered in corneal stromal cells upon Sp1 overexpression. The Sp1-induced alterations thus mimicked closely those observed in keratoconus, supporting the notion that Sp1 upregulation may be a key factor contributing directly to the disease development. Furthermore, the apoptotic activity was unaffected in Sp1 transfectants but the proliferation was inhibited, consistent with the idea that Sp1 may play a role in differentiation of corneal cells.

TRANSCRIPTION factors; PROTEINASES; WESTERN immunoblotting; CYTOCHEMISTRY; ENZYMES; CELL proliferation

Genes to Cells, 2009, Vol 14, Issue 10, p1133

1356-9597

Academic Journal

10.1111/j.1365-2443.2009.01340.x