Abstract
Abstract: :
Purpose: Recent studies have questioned the reported presence of the glucocorticoid receptor (GR) in bovine lens epithelium. The purpose of this study is to determine if the GR is expressed in cultured human and mouse lens epithelial cells and in human and mouse lens epithelia. Methods: Total RNA was extracted with RNAzol from freshly isolated human lens epithelia, mouse lenses and from confluent cultures of human (HLE-B3) and mouse (αTN4) immortalized epithelial cell lines. The expression of glucocorticoid receptor message was determined by RT-PCR using primers specific for human and mouse GR. RNA from mouse lung and NIH-3T3 cells served as positive controls and (-) RT reactions served as negative controls. Protein extracts from HLE-B3 cells, αTN4 cells, human lens epithelia and from HeLa nuclear extracts, NIH-3T3 cells, and commercially available partially purified GR, which served as positive controls, were resolved by electrophoresis on 7.5% polyacrylamide gels. Protein expression of the GR was determined by western blotting with H-300, a commercial polyclonal antibody against an epitope corresponding to an internal region (amino acids 121-420) of the glucocorticoid receptor. Results: RT-PCR of total RNA yielded the expected band sizes. Products detected in the mouse lung, NIH-3T3 cells, human lens epithelia, whole mouse lens, HLE-B3 cells and αTN4 cells were sequenced in both directions and found to have 97-100% homology with the GR. The glucocorticoid receptor is reported to have a MW of 95-kDa. A 95-kDa protein was detected by western blotting in extracts of positive controls and of the human and mouse cell lines and human lens epithelium. Conclusions: These results demonstrate expression of the glucocorticoid receptor in mouse and human lens epithelial cells. This suggests that glucocorticoids may act on the mouse and human lens directly during normal lens development and/or cataractogenesis.
Keywords: 377 corticosteroids • 417 gene/expression • 338 cataract