Lipopolysaccharide stimulation of 70 kilo Dalton heat shock protein messenger ribonucleic acid production in cultured human fetal membranes

Objective: The 70 kilo Dalton heat shock protein is upregulated when cells are under physiological stress. It prevents protein denaturation and incorr ect polypeptide assembly, and inhibits apoptosis as well as the transcripti on of genes coding for pro-inflammatory cytokines. To evaluate if up-regula tion of heat shock protein 70 can occur during pregnancy, we examined wheth er addition of bacterial lipopolysaccharide to human amniochorion membranes in vitro stimulated heat shock protein 70 gene transcription. Materials and methods: Amniochorionic membranes (n = 5), collected at the t ime of elective repeat cesarean section Frier to labor from normal term ges tations, were placed in an organ explant system. After 48 hour in culture, the membranes were stimulated with lipopolysaccharide for 24 hours. Total R NA was extracted and subjected to an oligo dT primed reverse transcriptase reaction followed by polymerase chain reaction (PCR) using heat shock prote in 70 specific primers. PCR products were hybridized with biotinylated inte rnal probes and identified by enzyme-linked immunosorbent assay (ELISA). Re sults were analyzed by Mann-Whitney U gene transcription. test. A p < 0.05 was significant. Results: Heat shock protein 70 messenger RNA was expressed by all fetal mem brane preparations both prior to and following in vitro culture. Addition o f lipopolysaccharide increased the concentrations of heat shock protein 70 messenger RNA in each sample tested from a mean of 35.5 <plus/minus> 29.6 n g/milliliter (12.1 - 80.1 ng/milliliter) to 169.6 +/- 69.9 ng/ml (51.7-218. 2 ng/milliliter) (p = 0.03). Conclusion: Human fetal membranes constitutively express heat shock protein 70 messenger ribonucleic acid. Bacterial lipopolysaccharide markedly stimu lated heat shock protein 70 messenger RNA gene transcription in human fetal membranes. Thus, heat shock protein 70 is inducible in fetal membranes and may facilitate fetal survival under adverse conditions.