Estrogen decreases TNF gene expression by blocking JNK activity and the resulting production of c-Jun and JunD
Sunil Srivastava, … , Stuart Adler, Roberto Pacifici
Sunil Srivastava, … , Stuart Adler, Roberto Pacifici
Published August 15, 1999
Citation Information: J Clin Invest. 1999;104(4):503-513. https://doi.org/10.1172/JCI7094.
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Article

Estrogen decreases TNF gene expression by blocking JNK activity and the resulting production of c-Jun and JunD

Abstract

Central to the bone-sparing effect of estrogen (E2) is its ability to block the monocytic production of the osteoclastogenic cytokine TNF-α (TNF). However, the mechanism by which E2 downregulates TNF production is presently unknown. Transient transfection studies in HeLa cells, an E2 receptor–negative line, suggest that E2 inhibits TNF gene expression through an effect mediated by estrogen receptor β (ERβ). We also report that in RAW 264.7 cells, an E2 receptor–positive murine monocytic line, E2 downregulates cytokine-induced TNF gene expression by decreasing the activity of the Jun NH2-terminal kinase (JNK). The resulting diminished phosphorylation of c-Jun and JunD at their NH2-termini decreases the ability of these nuclear proteins to autostimulate the expression of the c-Jun and JunD genes, thus leading to lower production of c-Jun and JunD. The consequent decrease in the nuclear levels of c-Jun and JunD leads to diminished binding of c-Jun/c-Fos and JunD/c-Fos heterodimers to the AP-1 consensus sequence in the TNF promoter and, thus, to decreased transactivation of the TNF gene.

Authors

Sunil Srivastava, M. Neale Weitzmann, Simone Cenci, F. Patrick Ross, Stuart Adler, Roberto Pacifici

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Figure 1

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RAW 264.7 cells express functional ERs and mRNA for ERα and ERβ. (a) Cel...
RAW 264.7 cells express functional ERs and mRNA for ERα and ERβ. (a) Cells were transfected with a reporter plasmid that contained a CAT gene under the transcriptional control of an ERE driven by an SV-40 promoter, and were treated with either E2 or control vehicle. CAT activity was normalized to β-galactosidase activity to correct for variability in transfection efficiency and expressed as normalized CAT activity. Mean ± SEM of 3 experiments. *P < 0.05 vs. untreated cells. (b) RT-PCR amplification products of ERα and ERβ. Total RNA was extracted and reverse transcribed. The resulting cDNA was amplified using primers specific for ERα and ERβ. Two amplification products corresponding to ERα and ERβ were detected by ethidium bromide staining of agarose gels. Amplification of purified mRNA with ERα and ERβ primers in the absence of RT generated no detectable bands (data not shown).