Abstract
Purpose:
Previously, we demonstrated that the secreted Ly6/uPAR-related protein-1 (Slurp1) is abundantly expressed in the cornea and is downregulated in diverse pro-inflammatory conditions. Here, we examine the effects of Slurp1 on corneal stromal fibroblast cell proliferation, interaction with the extracellular matrix (ECM), and migration, to understand the cellular basis of Slurp1 functions in the cornea.
Methods:
The effect of Slurp1 on corneal fibroblast behavior was assessed in vitro by treating human telomerase reverse transcriptase (hTERT)-immortalized mouse corneal stromal cell line MK/T1 with histidine-tagged mouse Slurp1 (His-Slurp1) produced in E. coli and partially purified by Ni ion resin column chromatography. Effect of His-Slurp1 on MK/T1 cell (i) density was assessed by crystal violet staining followed by measurement of absorbance at 590 nm, (ii) interaction with the ECM was evaluated on cell culture plates coated with different ECM components, and (iii) migration was assessed by in vitro gap filling assays.
Results:
Compared with the control, His-Slurp1-treated mouse corneal stromal fibroblast MK/T1 cells (i) density increased at a slower pace suggesting that Slurp1 inhibits cell proliferation, (ii) adhered with lower affinity to collagen-I-, collagen-IV-, vitronectin- or fibronectin-coated culture plates suggesting that Slurp1 affects cell-matrix interaction, and (iii) migrated at a slower pace in gap filling assays suggesting that Slurp1 inhibits cell migration.
Conclusions:
Our results demonstrate that Slurp1 inhibits corneal stromal fibroblast MK/T1 cell proliferation, cell-matrix adhesion and migration, revealing the cellular basis for corneal functions of Slurp1. These results are consistent with the decreased expression of Slurp1 in corneas exposed to pro-inflammatory conditions where the stromal fibroblasts proliferate at a higher rate, and migrate rapidly.
Keywords: 484 cornea: stroma and keratocytes •
486 cornea: tears/tear film/dry eye •
480 cornea: basic science