Effect of 43°C treatment on expression of heat shock proteins 105, 70 and 60 in cultured monkey Sertoli cells

Aim: To examine the possible effect of heat treatment on expression of heat shock proteins (Hsps) 105, 70, and 60 in primary monkey Sertoli cells and to evaluate the possible signal pathways. Methods: Western blot analysis, realtime polymerase chain reaction (PCR), and confocal immunohistochemistry were used to analyze mRNA and protein levels of the Hsps in response to 43°C treatment of Sertoli cells isolated from pubertal monkey testes. Results: Staining with Hoechst 33342 indicated Sertoli cells did not undergo apoptosis after heat treatment. Hsp105 was expressed in cytoplasm of untreated Sertoli cells. Both Hsp105 mRNA and protein levels were increased approximately 20-fold compared to those of the untreated controls at 12 h after heat treatment. Untreated Sertoli cells did not express Hsp70, but heat stress induced its expression in the cell cytoplasm. The time-course of changes in Hsp70 was similar to that of Hsp105. In contrast to Hsp105 and Hsp70, the change in Hsp60 expression was much less obvious. The protein level between 12 h and 48 h after heat treatment was only approximately 1.5-fold that of the untreated control. Extracellular regulated kinase (ERK) 1/2 inhibitor (U0126) or phosphoinositide kinase-3 (PI3K) inhibitor (LY294002) could partially block the response of Hsp105 and Hsp70 induced by heat treatment. Conclusion: These results indicate that the heat-induced expression of the three types of Hsp in monkey Sertoli cells might be regulated by ERK and/or PI3K signal pathways, but the profile of their expression is different, suggesting that they might have different regulatory functions in Sertoli cells.