Mol. Hum. Reprod. Advance Access originally published online on January 16, 2007
Molecular Human Reproduction 2007 13(3):181-187*; doi:10.1093/molehr/gal113
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Involvement of nuclear factor-kB activation through RhoA/Rho-kinase pathway in LPS-induced IL-8 production in human cervical stromal cells
Osaka University Graduate School of Medicine, Department of Obstetrics and Gynecology, Osaka, Japan
1 To whom correspondence should be addressed at: Department of Obstetrics and Gynecology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan. E-mail address: taharam{at}gyne.med.osaka-u.ac.jp
Interleukin-8 (IL-8) is a chemokine that recruits and activates neutrophils in stromal tissue and plays an essential role in cervical ripening. Nuclear factor-kB (NF-kB) is known to be important for the up-regulation of IL-8 gene expression. We examined the molecular mechanisms responsible for NF-kB activation in IL-8 production in cervical stromal cells. Lipopolysaccharide (LPS) and IL-1ß stimulated IL-8 production by cervical stromal cells in a dose-dependent manner. Pretreatment of cervical stromal cells with inhibitors of RhoA (C3 transferase exoenzyme), Rho-kinase (Y-27632) or NF-kB (BAY11-7082) effectively blocked LPS-induced IL-8 release. In contrast, IL-1ß-induced IL-8 production was significantly blocked by BAY11-7082, but not by C3 transferase exoenzyme or Y-27632. Pull-down assays showed that LPS activated RhoA, but IL-1ß caused only a lower level of activation. Transfection of the cervical stromal cells with RhoA small interfering RNA (siRNA) inhibited LPS-stimulated IL-8 production, whereas IL-1ß-induced IL-8 production was not significantly inhibited by knockdown of RhoA with siRNA. Using an NF-kB transcription reporter vector, luciferase assays demonstrated that incubation with LPS or IL-1ß induced the activation of NF-kB in cervical stromal cells. Activation of NF-kB by LPS was inhibited by treatment with C3 exoenzyme, Y-27632 or RhoA siRNA. However, inhibition of the RhoA/Rho-kinase pathway did not attenuate the activation of NF-kB by IL-1ß. These results suggest that LPS-induced IL-8 production is accompanied by enhanced NF-kB activation through the RhoA/Rho-kinase pathway in human cervical cells.
Key words: cervix/IL-8/RhoA/Rho-kinase/lipopolysaccharide/IL-1ß
* N.B. An error was made in the initial online pagination of Molecular Human Reproduction 13/3. The page span of this article was originally shown as 41–47. The publisher wishes to apologise for this error.
Submitted on October 24, 2006; resubmitted on November 20, 2006; accepted on November 30, 2006.