Induction of stress proteins in cultured human RPE-derived cells

The expression and induction of stress protein families were examined in cultured human fetal retinal pigment epithelial (RPE)-derived cells. These stress proteins (SPs) include the heat-shock proteins (HSPs) that have been shown to be highly inducible following treatment by heat, amino acid analogues, and various chemical oxidants. Three sets of proteins with molecular weights of 70, 84, and 110 kilodaltons were elevated simultaneously from constitutive levels after treatment with azetidine-2-carboxylic acid (AzC), an amino acid analogue of proline. Further experiments demonstrated that incubation of cultured human fetal RPE-derived cells with hydrogen peroxide (H2O2) at concentrations ranging from 10(-5) M to 10(-3) M for 30 minutes to 60 minutes did not elevate the levels of the common families of HSPs as with AzC. These results indicate that cultured human fetal RPE-derived cells are capable of elevated HSP biosynthesis after AzC exposure but appear resistant to H2O2 treatment.