| 10802388 |
Somji S, Todd JH, Sens MA, Garrett SH, Sens DA: Expression of heat shock protein 60 in human proximal tubule cells exposed to heat, sodium arsenite and CdCl (2). Toxicol Lett. 2000 May 19;115(2):127-36.
The expression of hsp 60 mRNA and protein were determined in human proximal tubule cells (HPT) exposed to lethal and sub-lethal concentrations of Cd (2+) under both acute and extended conditions of exposure. It was demonstrated that HPT cells exhibited the classic heat shock response when subjected to a physical (heat) or chemical stress (sodium arsenite). Heat stress, elevated temperature at 42.5 degrees C for 1 h, caused an increase in both hsp 60 mRNA and protein following removal of the stress. Similar results were obtained when the cells were subjected to a classic chemical stress of exposure to 100 microM sodium arsenite for 4 h. Acute exposure of HPT cells to 53.4 microM CdCl (2) for 4 h also resulted in an increase in hsp 60 mRNA and protein following removal of the metal. An extended exposure to Cd (2+) was modeled by treating the cells continuously with Cd (2+) at both lethal and sub-lethal levels over a 16-day time course. It was demonstrated that chronic exposure to Cd (2+) failed to increase either hsp 60 mRNA or protein expression in HPT cells, even at concentrations of Cd (2+) that were lethal to the cells during the time course. In fact, hsp 60 protein levels were decreased compared to controls at lethal levels of Cd (2+) exposure. These findings suggest that hsp 60 expression may have two distinct roles when the human proximal tubule cell is exposed to Cd (2+). A protective role through hsp 60 induction when the proximal tubule cell is acutely exposed to Cd (2+) and a deleterious role when hsp 60 protein is down-regulated during extended exposure to Cd (2+). |
12(0,0,1,7) |