Low levels of cadmium chloride alter the immunoprecipitation of corneal cadherin-complex proteins

The effect of cadmium chloride on the immunoprecipitation of cadherin and t he associated adherens junctional proteins, alpha- and beta -catenin, was e xamined in isolated bullfrog (Rana catesbeiana) corneas utilizing Western b lot and enhanced chemoluminescent techniques. Application of either 1.0 muM or 75.0 muM CdCl2 to the corneal endothelium for 2 h markedly decreased th e immunoprecipitation of cadherins as compared to paired control corneas. I mmunoprecipitation of alpha -catenin was increased in response to both dose s of CdCl2, while the immunoprecipitation of beta -catenin was little chang ed by either cadmium dose. There is accumulating evidence that cadmium may increase epithelial paracellular permeability by interfering with cadherin complex activity at intercellular junctions. The present study suggests tha t inorganic cadmium in low micromolar concentrations may decrease the integ rity of the corneal endothelium, at least in part through a similar mechani sm involving disruption of junctional cadherin complex function.