Lipopolysaccharide induces interleukin-8 production by human cervical smooth muscle cells.
OBJECTIVE
We examined the effect of lipopolysaccharide (LPS), a component of the outer wall of gram-negative bacteria, on expression of the neutrophil chemoattractant interleukin-8 (IL-8) and the effects of IL-8 treatment on release of matrix metabolizing enzymes in human cervical smooth muscle cells (CSMCs).


METHODS
Human CSMCs were exposed to Escherichia coli LPS, and the expression of IL-8 mRNA was analyzed by Northern blotting. The IL-8 promoter activity was examined by dual luciferase assay, and the IL-8 concentration was assessed by enzyme-linked immunosorbent assay. We also treated the CSMCs with human IL-8 and examined the expression of matrix-degrading enzymes.


RESULTS
E coli LPS (100 ng/mL) increased the expression of IL-8 mRNA 12.8-fold after 3 hours. This up-regulation was maintained for up to 24 hours. Lipopolysaccharide treatment produced a fivefold increase in IL-8 promoter activity in CSMCs transfected with an IL-8 promoter-reporter construct. IL-8 concentrations in conditioned medium of CSMC cultures treated with E coli LPS increased approximately 18-fold compared with the control cultures. Northern blot analysis and zymography revealed that exogenous human IL-8 had no significant effect on the expression of matrix metalloproteinase (MMP)-1, -3, and tissue inhibitor of metalloproteinase (TIMP)-1 mRNAs, and on the secretion MMP-2 and -9 in CSMCs.


CONCLUSIONS
We conclude that CSMCs respond to LPS with increased expression of IL-8 mRNA and secreted IL-8, and that expression of matrix metabolizing enzymes in CSMCs is not directly affected by IL-8. IL-8 produced by CSMCs in response to gram-negative infection may promote neutrophil invasion, and release of neutrophil matrix-degrading enzymes may participate in the matrix remodeling associated with parturition.
Watari
Michiko
M
Department of Obstetrics and Gynecology, Hokkaido University School of Medicine, Hokkaido, Japan. hmwatari@med.hokudai.ac.jp
Watari
Hidemichi
H
Fujimoto
Toshio
T
Yamada
Hideto
H
Nishihira
Jun
J
Strauss
Jerome F
JF
Fujimoto
Seiichiro
S
D002478:Cells, Cultured; D002584:Cervix Uteri / Q000166:cytology* / Q000378:metabolism; D003609:Dactinomycin / Q000494:pharmacology; D004926:Escherichia coli; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology*; D020781:Matrix Metalloproteinase 1 / Q000187:drug effects / Q000235:genetics; D020778:Matrix Metalloproteinase 2 / Q000187:drug effects / Q000378:metabolism; D019278:Matrix Metalloproteinase 3 / Q000187:drug effects / Q000235:genetics; D020780:Matrix Metalloproteinase 9 / Q000187:drug effects / Q000378:metabolism; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000187:drug effects; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000187:drug effects / Q000235:genetics
D016209:Interleukin-8; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D019715:Tissue Inhibitor of Metalloproteinase-1; D003609:Dactinomycin; D019278:Matrix Metalloproteinase 3; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; D020781:Matrix Metalloproteinase 1