Role of NF-κB in protection of heat shock pretreatment against TNF-α-induced endothelial cell apoptosis

AIM:To explore the role of nuclear factor kappa B (NF-κB) in protection of heat shock pretreatment against TNF-α induced endothelial cell apoptosis.METHODS: Cultured bovine pulmonary artery endothelial cells (BPAECs) were exposed to TNF-α(2 500 U/mL, 24 h) 16h after heat shock pretreatment(43℃,1h). The apoptotic morphological changes, DNA ladder pattern on agarose gel electrophoresis, and percentage of DNA fragmentation of BPAEC were analyzed. Inducible heat shock protein-70 kD(HSP70), inhibitor κBα(I-κBα) levels, expression of inducible nitric oxide synthase(iNOS) and NF-κB activity, NF-κB translocation to nuclei were detected using Western blot analysis, electrophoretic mobility shift assays (EMSA), and immunohistochemical analysis respectively.RESULTS:Heat shock pretreatment significantly attenuated TNF-α induced apoptosis in BPAEC. To compared with TNF-α treated BPAEC, heat shocked cells showed less apoptotic cells, no specific DNA ladder pattern agarose gel electrophoresis, and less increase of percentage of DNA fragmentation. Further, it was found that heat shock pretreatment induced expression of HSP70, and inhibited TNF-αmediated I-κBα degradation, NF-κB translocation, NF-κB binding activity, and iNOS expression.CONCLUSION: Heat shock pretreatment could protect BPAEC against TNF-α induced apoptosis, and its mechanism might involve HSP70 inhibition of TNF-α mediated NF-κB activity and iNOS expression.