Prostaglandins stimulate the stress-induced synthesis of hsp27 and αB crystallin

✍ Scribed by Hidenori Ito; Keiko Okamoto; Kanefusa Kato

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 258 KB
• Volume: 170
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/(sici)1097-4652(199703)170:3<255::aid-jcp6>3.0.co;2-n

✦ Synopsis

The effects were examined of various prostaglandins (prostaglandin A 1 , A 2 , J 2 , E 2 , and D 2 ) on the stress-induced accumulation of hsp27 and aB crystallin in C6 rat glioma cells. The levels of hsp27 and aB crystallin, which were determined by specific immunoassays, were low in cells in confluent cultures. The levels of the two proteins increased after exposure of cells to heat (42ЊC for 30 min) or arsenite (50 mM for 1 h). Cells exposed to 10 mM each of prostaglandin A 1 , A 2 , or J 2 for 1 h resulted in stimulation of the binding to the heat shock element (HSE) of heat shock transcription factor (HSF). However, there was no phosphorylationdependent mobility shift of HSF1 and no subsequent increase in the transcription and translation for hsp27, aB crystallin, and hsp70. When cells were exposed to arsenite in the presence of 10-40 mM prostaglandin, the accumulation of hsp27 and aB crystallin in cells was enhanced markedly. The levels of hsp70 also increased in cells that had been treated with arsenite in the presence of a prostaglandin, as estimated by Western blot analysis. Northern blot analysis revealed that the expression of messenger RNAs (mRNAs) for hsp27, aB crystallin, and hsp70 was enhanced in cells that had been exposed to arsenite in the presence of each prostaglandin. Similar stimulatory effects of prostaglandins also were observed in the case of the heat-induced responses of hsp27, aB crystallin, and hsp70. Gel mobility shift assays revealed that each prostaglandin prolonged the arsenite-induced binding of HSF to HSE. These results suggest that the pharmacological dose of prostaglandins stimulates the stress-induced synthesis of stress proteins via activation of the HSF.