Characterization of cAMP-dependent inhibition of LPS-induced TNF alpha production by rolipram, a specific phosphodiesterase IV (PDE IV) inhibitor (original) (raw)
Related papers
International Journal of Immunopharmacology, 1994
Bacterial endotoxins (lipopolysaccharide or LPS) provoke shock and tissue injury by eliciting the release of toxic factors from reticuloendothelial cells. One of the principal endogenous factors involved in this process is tumor necrosis factor alpha (TNFa). In this study, inhibitors selective for different classes of phosphodiesterases (PDE), were examined for their effects on LPS-induced TNFa production by human monocytes. The selective cAMP-PDE IV inhibitors, rolipram and RO-20-1724 were capable of inhibiting LPS-induced TNFa production by human monocytes in a concentration-dependent manner. Rolipram was used to examine further the cellular pharmacology of PDE IV inhibitors on cytokine production. The ~c50 for inhibition of LPS-induced TNFa production by rolipram was 0.1 ~M, whereas production of IL-1/3 or IL-6 was unaffected. Furthermore, rolipram was equally effective in inhibiting TNFa production by a number of other stimuli. Inhibition of TNFa production by rolipram was associated with an elevation of intracellular cAMP, consistent with a mechanism involving phosphodiesterase inhibition. Rolipram was efficacious in suppressing LPS-induced TNFa mRNA expression, and at the protein level was also active when added to cultures post-stimulated with LPS. This indicates that rolipram may act at both the transcriptional and translational levels. Rolipram inhibited TNFa production in vivo in a rat endotoxemia model. Collectively, these data suggest that the prototypic inhibitor of PDE IV isozyme, rolipram, can effectively and selectively inhibit LPS-induced TNFa production through elevation of intracellular cAMP.
International Journal of Immunopharmacology, 1995
Compounds suppressing the production of tumor necrosis factor-a are protective in animal models of septic shock. Recent studies demonstrated a beneficial effect of xanthine derivatives, which suppress tumor necrosis factor-a production by acting as non-specific cAMP phosphodiesterase inhibitors. In this experiment we tested the effect of (±)-rolipram (racemate) and its enantiomers on human mononuclear cells stimulated with lipopolysaccharide (LPS). Rolipram has a phenyl-pyrrolidinone structure, unrelated to the methylxanthines, and acts as a specific inhibitor of the type IV phosphodiesterase. Our results identify rolipram as a remarkably potent suppressor of the LPS-induced synthesis of tumor necrosis factor-a. When compared to the non-specific inhibitor pentoxifylline, the ICs0 of (±)-rolipram (130 nM) is more than 500 times lower. The influence of rolipram on tumor necrosis factor-a production depended on the steric configuration of the molecule, since the ( -)-enantiomer exhibited a five times lower lC~0 than the ( + )-enantiomer. The inhibitory effect of all substances tested is selective for tumor necrosis factor-a rather than interleukin-lfl, since interleukin-lp production is only slightly influenced.
Cell Biochemistry and Biophysics, 1998
Lipopolysaccharide (LPS)-induced liver injury in mice and LPS-induced tumor necrosis factor-or (TNF-ot) generation by murine macrophages and hepatocytes are suppressed markedly by agents that elevate intracellular cAMP. Phosphodiesterase (PDE)-4 inhibitors, J]2-adrenoceptor agonists, and E-series prostaglandins also attenuate the induction of the TNF-~x gene in human monocytes in response to bacterial LPS. The mechanism of action of cAMP is unclear, but in the mouse, is believed to involve the generation of the anti-inflammatory cytokine, interleukin-10 (IL-10). In this article, we describe the results of studies designed to determine the extent to which IL-10 contributes to the suppression of TNF-a generation from LPS-stimulated human monocytes evoked by 8-bromo cyclic AMP (8-Br-cAMP), rolipram, salbutamol, and prostaglandin E 2 (PGE2). LPS evoked a time-and concentration-dependent generation of TNF-ot (tl/2 = 4.5 h; EC50 = 273 pg/mL), which was inhibited by exogenous human recombinant (h) IL-10 (IC50 = 124 pg/mL), and by rolipram (ECs0 = 420 nM), 8-Br-cAMP (EC50 = 77 (~tM), PGE 2 (EC50 = 15 nM) and salbutamol (EC50 = 20 nM). In addition, 8-Br-cAMP, PGE 2, and salbutamol (but not rolipram) augmented significantly LPS-induced IL-10 production (two-to fivefold) under identical experimental conditions. Pretreatment of monocytes with an anti-IL-10 monoclonal antibody (MAb) that abolished the inhibitory action of a maximally effective concentration of exogenous hrIL-10, failed to attenuate the inhibitory effect of rolipram, PGE 2, salbutamol, and 8-Br-cAMP. Anti-IL-10 was similarly inactive when the number of monocytes seeded was increased from 0.5 to 4 x 106/mL or when measurements were made at 42 h post-LPS, a time when the concentration of IL-10 released was maximal. Collectively, these data suggest that in contrast to murine hepatocytes and macrophages, IL-10 does not mediate the inhibitory effect of cAMP-elevating drugs on TNF-a generation from human monocytes. Although the reason for this discrepancy is unclear, we suggest that the influence of cAMP on the transcriptional regulation of the TNF-ot gene differs between species or when monocytes have differentiated into macrophages.
Pulmonary pharmacology & therapeutics, 2005
Chronic obstructive pulmonary disease (COPD) is a common, progressive respiratory disease that causes great morbidity and mortality despite treatment. Tumor necrosis factor alpha (TNF-alpha) plays a central role as a pro-inflammatory cytokine in COPD. TNF-alpha release is markedly inhibited by phosphodiesterase type 4 (PDE4) inhibitors that have proven efficacious in COPD clinical trials. The aim of this study was to compare the in vitro activities of the novel selective PDE4 inhibitors CI-1044 compared to well-known PDE4 inhibitors, rolipram and cilomilast, and to the glucocorticoid dexamethasone at reducing lipopolysaccharide (LPS)-induced TNF-alpha release in whole blood from COPD patients and healthy subjects. In the whole blood from COPD patients pre-incubation with PDE4 inhibitors or dexamethasone resulted in a dose-dependent inhibition of LPS-induced TNF-alpha release with IC(50) values of 1.3+/-0.7, 2.8+/-0.9 microM, higher to 10 microM and lesser than 0.03 microM for CI-104...
Brain, behavior, and immunity, 2017
Inhibitors of phosphodiesterase-4 (PDE4) have been approved for the treatment of inflammatory disorders, but are associated with dose-limiting nausea and vomiting. These side effects are hypothesized to be mediated by inhibition of the PDE4D isozyme. Here we demonstrate the anti-inflammatory effects of the novel brain penetrant PDE4D-sparing PDE4 inhibitor, ABI-4. ABI-4 was a potent (EC50∼14nM) inhibitor of lipopolysaccharide (LPS) induced TNF-α release from mouse microglia and human PBMCs. ABI-4 (0.32mg/kg) blocked LPS-induced release of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) in blood and brain of mice. In a rat model of endotoxin induced uveitis, ABI-4 (0.03-0.3mg/kg) demonstrated steroid-like efficacy in preventing leucocyte infiltration of the aqueous humor when administered 4h after LPS. LPS (0.32mg/kg×5days) caused a 30% upregulation of translocator protein (TSPO) binding which was prevented by co-administration of ABI-4 (0.32mg/kg). In a paradigm to assess motivation...
Comparative biochemistry and physiology. Part C, Pharmacology, toxicology & endocrinology, 1995
The effects of a selective phosphodiesterase (PDE) type IV inhibitor, rolipram, on activation of neutrophil phospholipases in response to the chemotactic peptide formyl-methiony-leucyl-phenylalanine (fMLP) were investigated. fMLP caused liberation of arachidonic acid, a precursor of eicosanoids and in the presence of 0.3% butanol, production of phosphatidylbutanol, an indicator of phospholipase D activation. Rolipram inhibited arachidonic acid release and phosphatidylbutanol formation. The inhibition was considered to be mediated through a cAMP-dependent mechanism, probably protein kinase A, because selective inhibitors for protein kinase A, H-8 or H-89 overcame the action of rolipram. The concentration-dependent inhibitory profile for phospholipase D activation was similar to that for lysosomal enzyme release, providing additional evidence for the functional link of these two events. In contrast, rolipram was without effect on fMLP-induced inositol trisphosphate production. These r...
Cell Biochem Biophys, 1998
Lipopolysaccharide (LPS)-induced liver injury in mice and LPS-induced tumor necrosis factor-or (TNF-ot) generation by murine macrophages and hepatocytes are suppressed markedly by agents that elevate intracellular cAMP. Phosphodiesterase (PDE)-4 inhibitors, J]2-adrenoceptor agonists, and E-series prostaglandins also attenuate the induction of the TNF-~x gene in human monocytes in response to bacterial LPS. The mechanism of action of cAMP is unclear, but in the mouse, is believed to involve the generation of the anti-inflammatory cytokine, interleukin-10 (IL-10). In this article, we describe the results of studies designed to determine the extent to which IL-10 contributes to the suppression of TNF-a generation from LPS-stimulated *Author to whom all correspondence and reprint requests should be addressed.
Pulmonary Pharmacology & Therapeutics, 2005
The extent to which cAMP-dependent protein kinase (PKA) mediates the inhibitory effects of cAMP-elevating drugs on tumour necrosis factor (TNF) a release from lipopolysaccharide (LPS)-stimulated human monocytes is equivocal. Here, we have investigated the role of this kinase by exploiting the ability of certain novel cAMP analogues to inhibit or activate PKA and the recently described cAMP-guanine nucleotide-exchange factors (GEFs). Pre-treatment of monocytes with Rp-8-Br-cAMPS, a selective inhibitor of Type I PKA that has no effect on basal or stimulated Rap1 (a downstream effector of cAMP-GEFs) activity, potentiated LPS-induced TNFa output but had little or no effect on the suppression of this cytokine effected by rolipram (a PDE4 inhibitor), prostaglandin (PG) E 2 and salbutamol (a b 2 -adrenoceptor agonist). In contrast, Rp-8-pCPT-cAMPS, which selectively blocks Type II PKA with only weak activity against Rap1, significantly antagonised or abolished the inhibitory effect of these cAMP-elevating agents. Pre-treatment of monocytes with 8-pCPT-2 0 -O-Me-cAMPS, a potent activator of cAMP-GEFs, failed to suppress TNFa output at concentrations known to profoundly activate Rap1. Collectively, these results indicate that cAMP-elevating drugs suppress TNFa release from LPS-stimulated human monocytes by activating PKA independently of cAMP-GEFs. Furthermore, by using phosphorothioate cAMP analogue PKA inhibitors we provide evidence that the Type II PKA isoenzyme is functionally the most important. q
Journal of pharmacology & pharmacotherapeutics
To investigate the impact of the phophodiesterase-4 inhibition (PD-4-I) with rolipram on hepatic integrity in lipopolysaccharide (LPS) induced hyperinflammation. Liver microcirculation in rats was obtained using intravital microscopy. Macrohemodynamic parameters, blood assays, and organs were harvested to determine organ function and injury. Hyperinflammation was induced by LPS and PD-4-I rolipram was administered intravenously one hour after LPS application. Cell viability of HepG2 cells was measured by EZ4U-kit based on the dye XTT. Experiments were carried out assessing the influence of different concentrations of tumor necrosis factor alpha (TNF-α) and LPS with or without PD-4-I. Untreated LPS-induced rats showed significantly decreased liver microcirculation and increased hepatic cell death, whereas LPS + PD-4-I treatment could improve hepatic volumetric flow and cell death to control level whithout influencing the inflammatory impact. In HepG2 cells TNF-α and LPS significantly...