Recently isolated trophoblasts express nitric oxide synthase 2 (NOS-2) and cyclooxygenase 2 (COX-2), decreasing the levels of the corresponding mRNAs when the cells were maintained in culture. The sustained expression of COX-2 and NOS-2 in trophoblasts was dependent on the activation of nuclear factor kappaB (NF-kappaB) since proteasome inhibitors and antioxidants that abrogated NF-kappaB activity suppressed the induction of both genes. The time-dependent fall of the mRNA levels of NOS-2 and COX-2 paralleled the inhibition of NF-kappaB, determined by electrophoretic mobility shift assays, and the increase of the IkappaBalpha and IkappaBbeta inhibitory proteins. Isolated trophoblasts synthesized reactive oxygen intermediates (ROI), a process impaired after culturing the cells, and that might be involved in the NF-kappaB activation process. Moreover, treatment of recently isolated cells with ROI scavengers suppressed the expression of COX-2 and NOS-2. Challenge of trophoblasts with interleukin-1beta up-regulated the expression of both proteins, an effect that was potentiated by lipopolysaccharide. These results indicate that the physiological expression of NOS-2 and COX-2 in trophoblasts involves a sustained activation of NF-kappaB which inhibition abrogates the inducibility of both genes.
Requirement of nuclear factor kappaB for the constitutive expression of nitric oxide synthase-2 and cyclooxygenase-2 in rat trophoblasts
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N.A. Callejas, M. Casado, L. Bosca, P. Martin-Sanz; Requirement of nuclear factor kappaB for the constitutive expression of nitric oxide synthase-2 and cyclooxygenase-2 in rat trophoblasts. J Cell Sci 15 September 1999; 112 (18): 3147–3155. doi: https://doi.org/10.1242/jcs.112.18.3147
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