Knockdown of IQGAP-1 Enhances Tight Junctions and Prevents Invasion of Human Corneal Epithelial Cells.

<bold>Purpose: </bold>To determine the role of IQ-domain GTPase-activating protein1 (IQGAP-1) in tight junctions of human corneal epithelial cells (HCECs) and its effect against P. aeruginosa (PAK) invasion.<bold>Material and Methods: </bold>Primary human corneal epithelial cells (HCECs), immortalized HCECs, and IQGAP-1 RNA knockdown HCECs (siHCECs) were used. Confocal microscopy, transepithelial electrical resistance (TER), trypan blue exclusion assay and gentamicin invasion assay were done.<bold>Results: </bold>In primary and immortalized HCECs, IQGAP-1 co-localized with zonular occludin-1 (ZO-1) and actin. Enhanced actin and ZO-1 aggregation were seen in siHCECs. IQGAP-1 knockdown significantly increased TER of immortalized HCECs (P < .0001). Cell viability after PAK infection increased for siHCECs for up to 4 h after infection. PAK intracellular invasion was significantly lowered by 50% in siHCECs at 1 h post-infection.<bold>Conclusion: </bold>IQGAP-1 knockdown increased the strength and integrity of tight junctions and may provide an early protective effect against P. aeruginosa invasion. [ABSTRACT FROM AUTHOR]