Thymosin beta4 promotes human conjunctival epithelial cell migration.

PURPOSE: In this study the effects of thymosin beta4 (Tbeta4) on migration and production of laminin-5 in the human conjunctival cell line HC0597 was analyzed. METHODS: Boyden chamber assays assessed the ability of Tbeta4 to stimulate in vitro cell migration. Control or Tbeta4-treated cells were processed for immunofluorescence microscopy using antibodies to vinculin or laminin-5. Cell lysates were processed for Western blot and densitometric analysis using antibodies to laminin-5 alpha3 or gamma2 chains. RESULTS: Tbeta4 stimulated migration in a dose-dependent manner. Focal adhesions present in Tbeta4-treated cells were smaller and more rounded compared to the "streaks" characteristic of controls. Western blot analysis and densitometry revealed that Tbeta4-treated cells expressed more laminin-5 alpha3 and gamma2 chain protein. CONCLUSION: Tbeta4 stimulates in vitro conjunctival epithelial cell migration, and results in altered focal adhesion formation and increased extracellular laminin-5 deposition. The increased migration may be correlated with increased production of laminin-5.