Induction of stress proteins in human endothelial cells by heavy metal ions and heat shock

In the present study, we compared the induction of heat shock proteins (HSP s) by heat and heavy metal ions in three different endothelial cell types, namely, human umbilical vein endothelial cells, human pulmonary microvascul ar endothelial cells, and the cell line EA.hy 926. Our results show that es pecially Zn2+ and Cd2+ are inducers of 70-kDa (HSP70), 60-kDa (HSP60), 32-k Da (HSP32), and 27-kDa (HSP27) HSPs. The strength of inducibility is specif ic for each HSP. Ni2+ and Co2+ only show an inducible effect at very high c oncentrations, that is, in the clearly cytotoxic range. Furthermore, we inv estigated the time course of HSP expression and the involvement of heat sho ck factor-1. Our study demonstrates that the three endothelial cell types t hat were under investigation show comparable stress protein expression when treated with heavy metal ions or heat shock. The expression of stress prot eins may be used as an early marker for the toxic damage of cells. This dam age can be an inducer of acute respiratory distress syndrome in which micro vascular endothelial lesions occur early. Our study provides evidence that human umbilical vein endothelial cells or EA.hy 926 cells, which are much m ore easily isolated and/or cultivated than pulmonary microvascular endothel ial cells, could be used as alternative cell culture systems for studies on cellular dysfunction in the lung caused by toxic substances, certainly wit h respect to the expression of HSPs.