H-7 disrupts the actin cytoskeleton and increases outflow facility.

OBJECTIVES To determine the effects of the serine-threonine kinase inhibitor H-7 on (1) cell junctions and the attached actin-based cytoskeleton in cultured bovine aortic endothelial cells, and (2) outflow facility in living monkeys. METHODS Bovine aortic endothelial cells were cultured by standard techniques. The architecture and distribution of actin filaments, vinculin, and beta-catenin in bovine aortic endothelial cells were studied by immunolabeling before and after exposure to H-7 at various concentrations and durations. Outflow facility (perfusion) and intraocular pressure (Goldmann tonometer) were determined before and after the intracameral or topical administration of H-7 or a vehicle. RESULTS In bovine aortic endothelial cells, exposure to H-7 produced a reversible time- and concentration-dependent disruption of actin microfilaments and an alteration in the organization of cell-cell and cell-matrix adhesions. In monkeys, intracameral and topical administration of H-7 dose dependently and reversibly doubled facility, and topical H-7 reduced intraocular pressures. CONCLUSION H-7 increases outflow facility in monkeys, probably by inhibiting cell contractility, cytoskeletal support, and cell-cell adhesions in the trabecular meshwork.