Gene Expression Analysis of Heat Shock Protein A Family Members Responsive to Hyperthermic Treatments in Normal Human Fibroblastic Cells

Abstract

Heat shock protein A (HSPA)family members consist of at least 13 genes. We studied the effects of heat stress on the gene expression of HSPA family members in normal human fibroblastic (NHF) cells. Four NHF cell lines, Hs68, OUMS-36, NTI-4, and KD, were treated with mild hyperthermia(MHT)at 41°C for 30 min or hyperthermia(HT)at 43°C for 30 min,followed by culturing for 1 or 24 h at 37°C.Treatment of cells with HT significantly induced cell death,whereas this change was not observed in cells treated with MHT. Real-time quantitative polymerase chain reaction demonstrated that the expression levels of HSPA1A,HSPA1B,HSPA1L,HSPA4,HSPA4L,HSPA5 and HSPA6 were significantly elevated in the cells treated with MHT and HT,and the HT treatment was more effective than the MHT treatment. This report is the first to describe an increase in HSPA4 expression by heat treatment. These alterations were observed in all four NHF cell lines in the same way. On the other hand, neither MHT nor HT affected the expression levels of HSPA2, HSPA8, HSPA9, HSPA12A, HSPA13 and HSPA14. These results demonstrated that HSPA1A, HSPA1B, HSPA1L, HSPA4, HSPA4L, HSPA5 and HSPA6 were heat-inducible HSPA genes, but the remaining HSPA family members were constitutive(not heat-inducible)HSPA genes. Under the non-heated condition at 37°C, the expression levels of constitutive HSPA genes were higher than those of heat-inducible HSPA genes. In conclusion,the gene expression patterns of HSPA family members responsive to heat stresses in NHF cells were identified. These results may provide a basis for understanding the molecular mechanisms of MHT and HT in normal cells.