Cyclic AMP increases endogenous granulocyte colony‐stimulating factor formation in monocytes and THP‐1 macrophages despite attenuated TNF‐α formation

Abstract

The cytokine granulocyte colony-stimulating factor (G-CSF) is in broad clinical use to treat neutropenia, and trials on its use in immunosuppressed conditions and infections are ongoing. To apply G-CSF effectively, it is crucial to understand the regulation and distribution of its endogenous formation. Since G-CSF release is mediated, at least in part, by TNF- § formation, we investigated whether drugs suppressing TNF- § also impair G-CSF production. Surprisingly, G-CSF formation was enhanced in lipopolysaccharide (LPS)-stimulated blood from a pentoxifylline-treated patient. In the presence of dibutyryl-cAMP, forskolin, tolafentrine or 3-isobutyl-1-methylxanthine, LPS-induced G-CSF formation was enhanced in THP-1 cells, primary monocytes and whole blood. Correspondingly, rp-8-bromo-cAMP suppressed LPS-induced G-CSF release. Addition of prostaglandin E 2 enhanced and indomethacin suppressed G-CSF formation. Reporter gene studies showed that dibutyryl-cAMP enhanced LPS-induced G-CSF promoter activity, indicating a transcriptional up-regulation. Furthermore, disruption of a newly identified putative cAMP-responsive element (CRE) in the G-CSF promoter demonstrated the regulatory role for G-CSF gene transcription. In conclusion, endogenous G-CSF formation critically depends on both TNF- § and cyclooxygenase products, exerting effects via cAMP and the CRE in the G-CSF promoter. This might have bearing for drug side effects, putative G-CSF mimetics and our understanding of G-CSF immunobiology.

Prostaglandin E2 Stimulates Granulocyte Colony-Stimulating Factor Production via the Prostanoid EP2 Receptor in Mouse Peritoneal Neutrophils

“…Then, which cell type is responsible for the G-CSF production, resident macrophages, or the newly elicited neutrophils? We found that in the murine resident peritoneal macrophages, PGE 2 augmented LPS-induced G-CSF production as Hareng et al (13) reported for THP-1 cells. However, in the case of the macrophages, EP4 is responsible for the PGE 2 potentiation of G-CSF release because an EP4 agonist mimicked the effect of PGE 2 more effectively than an EP2 agonist (D. Mori, S. Tsuchiya, and Y. Sugimoto, unpublished observation).…”

“…PGE 2 in most cases promotes or inhibits the production of cytokines and chemokines induced by stimuli such as LPS or TNF-␣ and thus has been considered to be a modulator of immune responses (30). Indeed, it has been shown that endogenous PGE 2 contributes to LPS-induced G-CSF gene expression in monocytes (12,13). Hareng et al (13) recently demonstrated that dbcAMP enhances LPS-primed promoter activity via a cAMP-responsive element located at Ϫ240 bp of the G-CSF gene in THP-1 cells.…”

“…Indeed, it has been shown that endogenous PGE 2 contributes to LPS-induced G-CSF gene expression in monocytes (12,13). Hareng et al (13) recently demonstrated that dbcAMP enhances LPS-primed promoter activity via a cAMP-responsive element located at Ϫ240 bp of the G-CSF gene in THP-1 cells. We also found that indomethacin inhibits LPS-induced G-CSF production and that PGE 2 reverses this inhibition in the murine resident peritoneal macrophages (D. Mori, S. Tsuchiya, and Y. Sugimoto, unpublished observation).…”

“…Indeed, in the casein-induced peritonitis model, G-CSF is produced in the peritoneal cavity at the time of neutrophil migration, suggesting that neutrophils can produce G-CSF for this purpose (11). PGE 2 has been shown to enhance LPS-induced G-CSF formation in human monocyte or macrophage-like THP-1 cells (12,13). However, it remains unknown whether PGE 2 modulates G-CSF formation from neutrophils, and there are no reports evaluating the contribution of PGE 2 to local G-CSF production within an inflammatory area.…”

Cyclic adenosine monophosphate signaling and organ dysfunction in septic shock

“…Cyclic AMP signaling is also demonstrated to induce IL-6 and granulocyte colony-stimulating factor, possibly through prostaglandin (PG)E2-mediated autoregulation (17,18). The cAMPmediated induction of these genes is PKA-dependent and involves binding of CRE-binding protein and CAAT/enhancer binding protein transcription factors to the genetic promoter elements (17,19).…”