Transforming growth factor-beta inhibits lipopolysaccharide-stimulated expression of inflammatory cytokines in mouse macrophages through downregulation of activation protein 1 and CD14 receptor expression.
The septic shock that occurs in gram-negative infections is caused by a cascade of inflammatory cytokines. Several studies showed that transforming growth factor-beta1 (TGF-beta1) inhibits this septic shock through suppression of expression of the lipopolysaccharide (LPS)-induced inflammatory cytokines. In this study, we investigated whether TGF-beta1 inhibition of LPS-induced expression of inflammatory cytokines in the septic shock results from downregulation of LPS-stimulated expression of CD14, an LPS receptor. TGF-beta1 markedly inhibited LPS stimulation of CD14 mRNA and protein levels in mouse macrophages. LPS-stimulated expression of CD14 was dramatically inhibited by addition of antisense, but not sense, c-fos and c-jun oligonucleotides. Since TGF-beta1 pretreatment inhibited LPS-stimulated expression of c-fos and c-jun genes and also the binding of nuclear proteins to the consensus sequence of the binding site for activation protein 1 (AP-1), a heterodimer of c-Fos and c-Jun, in the cells, TGF-beta1 inhibition of CD14 expression may be a consequence of downregulation of AP-1. LPS-stimulated expression of interleukin-1beta and tumor necrosis factor alpha genes in the cells was inhibited by addition of CD14 antisense oligonucleotide. Also, TGF-beta1 inhibited the LPS-stimulated production of both inflammatory cytokines by the macrophages. In addition, TGF-beta1 inhibited expression of the two cytokines in several organs of mice receiving LPS. Thus, our results suggest that TGF-beta1 inhibition of LPS-stimulated inflammatory responses resulted from downregulation of CD14 and also may be a possible mechanism of TGF-beta1 inhibition of LPS-induced septic shock.
Imai
K
K
Department of Oral Microbiology, Meikai University School of Dentistry, Keyakidai, Sakado City, Saitama 350-0283, Japan.
Takeshita
A
A
Hanazawa
S
S
D000818:Animals; D002478:Cells, Cultured; D015536:Down-Regulation / Q000187:drug effects; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics*; D007668:Kidney / Q000378:metabolism; D018950:Lipopolysaccharide Receptors / Q000235:genetics / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000276:immunology / Q000494:pharmacology; D008099:Liver / Q000378:metabolism; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D013154:Spleen / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000008:administration & dosage / Q000378:metabolism* / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
D007375:Interleukin-1; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D018808:Transcription Factor AP-1; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha