Limits...
Azithromycin inhibits IL-1 secretion and non-canonical inflammasome activation.

Gualdoni GA, Lingscheid T, Schmetterer KG, Hennig A, Steinberger P, Zlabinger GJ - Sci Rep (2015)

Bottom Line: Interference with Ca(++)-dependent uptake abolished the cytokine-modulatory effect, suggesting a role of intracellular azithromycin accumulation in the modulatory role of this macrolide.Azithromycin's inhibiting effects were observed upon LPS, but not upon flagellin, stimulation.We provide the first evidence of a differential impact of macrolides on the inflammasome/IL-1β axis, which may be of relevance in inflammasome-driven diseases such as chronic obstructive pulmonary disease or asthma.

View Article: PubMed Central - PubMed

Affiliation: Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.

ABSTRACT
Deregulation of inflammasome activation was recently identified to be involved in the pathogenesis of various inflammatory diseases. Although macrolide antibiotics display well described immunomodulatory properties, presumably involved in their clinical effects, their impact on inflammasome activation has not been investigated. We compared the influence of macrolides on cytokine induction in human monocytes. The role of intracellular azithromycin-accumulation was examined by interference with Ca(++)-dependent uptake. We have also analysed the signalling cascades involved in inflammasome activation, and substantiated the findings in a murine sepsis model. Azithromycin, but not clarithromycin or roxithromycin, specifically inhibited IL-1α and IL-1β secretion upon LPS stimulation. Interference with Ca(++)-dependent uptake abolished the cytokine-modulatory effect, suggesting a role of intracellular azithromycin accumulation in the modulatory role of this macrolide. Azithromycin's inhibiting effects were observed upon LPS, but not upon flagellin, stimulation. Consistent with this observation, we found impaired induction of the LPS-sensing caspase-4 whereas NF-κB signalling was unaffected. Furthermore, azithromycin specifically affected IL-1β levels in a murine endotoxin sepsis model. We provide the first evidence of a differential impact of macrolides on the inflammasome/IL-1β axis, which may be of relevance in inflammasome-driven diseases such as chronic obstructive pulmonary disease or asthma.

No MeSH data available.


Related in: MedlinePlus

Azithromycin specifically inhibits IL-1β secretion upon LPS stimulation in human monocytes.Panel a)-d) show the impact of azithromycin on cytokine release of LPS or flagellin stimulated human monocytes. Cells were treated with the indicated concentrations of azithromycin and stimulated with either 100 ng/ml LPS or 100 ng/ml Flagellin for 20 h. After co-incubation, cell culture supernatants were analysed for the presence of the indicated cytokines by Luminex®. Values are expressed as mean ± SEM from 6 independent experiments. *Significant compared to LPS/flagellin alone, p < 0.05 calculated by paired t-test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4495566&req=5

f1: Azithromycin specifically inhibits IL-1β secretion upon LPS stimulation in human monocytes.Panel a)-d) show the impact of azithromycin on cytokine release of LPS or flagellin stimulated human monocytes. Cells were treated with the indicated concentrations of azithromycin and stimulated with either 100 ng/ml LPS or 100 ng/ml Flagellin for 20 h. After co-incubation, cell culture supernatants were analysed for the presence of the indicated cytokines by Luminex®. Values are expressed as mean ± SEM from 6 independent experiments. *Significant compared to LPS/flagellin alone, p < 0.05 calculated by paired t-test.

Mentions: Since clinical evidence suggests beneficial effects of azithromycin on inflammasome-driven diseases49, we initially focused on this compound when analysing the impact of macrolides on pro-inflammatory cytokine release. In line with previous reports2627, LPS stimulation alone was sufficient to induce a potent IL-1β release from human monocytes (Suppl. Table S1). Intriguingly, when stimulating human monocytes with LPS, azithromycin treatment significantly inhibited IL-1β secretion in a dose-dependent manner (Fig. 1a, Suppl. Table S1), whereas the induction of other monocyte-derived pro-inflammatory cytokines such as tumor necrosis factor (TNF)-α, IL-6, and IL-8 was unaffected (Fig. 1b–d, Suppl. Table S1). In contrast, when stimulated with flagellin, a TLR-5 ligand and an activator of the NLRC4 inflammasome, azithromycin treatment had no substantial effect on IL-1β secretion (Fig. 1a, Suppl. Table S1), and similar to LPS stimulation, the release of the other cytokines (TNF-α, IL-6, and IL-8) was not affected (Fig. 1b–d, Suppl. Table S1). Azithromycin in the doses used in these experiments did not exhibit significant effects on cell viability (Suppl. Fig. S1). These findings outline a specific and dose-dependent impact of azithromycin on the inflammatory caspase axis, leading to the inhibition of IL-1β maturation in human monocytes.


Azithromycin inhibits IL-1 secretion and non-canonical inflammasome activation.

Gualdoni GA, Lingscheid T, Schmetterer KG, Hennig A, Steinberger P, Zlabinger GJ - Sci Rep (2015)

Azithromycin specifically inhibits IL-1β secretion upon LPS stimulation in human monocytes.Panel a)-d) show the impact of azithromycin on cytokine release of LPS or flagellin stimulated human monocytes. Cells were treated with the indicated concentrations of azithromycin and stimulated with either 100 ng/ml LPS or 100 ng/ml Flagellin for 20 h. After co-incubation, cell culture supernatants were analysed for the presence of the indicated cytokines by Luminex®. Values are expressed as mean ± SEM from 6 independent experiments. *Significant compared to LPS/flagellin alone, p < 0.05 calculated by paired t-test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4495566&req=5

f1: Azithromycin specifically inhibits IL-1β secretion upon LPS stimulation in human monocytes.Panel a)-d) show the impact of azithromycin on cytokine release of LPS or flagellin stimulated human monocytes. Cells were treated with the indicated concentrations of azithromycin and stimulated with either 100 ng/ml LPS or 100 ng/ml Flagellin for 20 h. After co-incubation, cell culture supernatants were analysed for the presence of the indicated cytokines by Luminex®. Values are expressed as mean ± SEM from 6 independent experiments. *Significant compared to LPS/flagellin alone, p < 0.05 calculated by paired t-test.
Mentions: Since clinical evidence suggests beneficial effects of azithromycin on inflammasome-driven diseases49, we initially focused on this compound when analysing the impact of macrolides on pro-inflammatory cytokine release. In line with previous reports2627, LPS stimulation alone was sufficient to induce a potent IL-1β release from human monocytes (Suppl. Table S1). Intriguingly, when stimulating human monocytes with LPS, azithromycin treatment significantly inhibited IL-1β secretion in a dose-dependent manner (Fig. 1a, Suppl. Table S1), whereas the induction of other monocyte-derived pro-inflammatory cytokines such as tumor necrosis factor (TNF)-α, IL-6, and IL-8 was unaffected (Fig. 1b–d, Suppl. Table S1). In contrast, when stimulated with flagellin, a TLR-5 ligand and an activator of the NLRC4 inflammasome, azithromycin treatment had no substantial effect on IL-1β secretion (Fig. 1a, Suppl. Table S1), and similar to LPS stimulation, the release of the other cytokines (TNF-α, IL-6, and IL-8) was not affected (Fig. 1b–d, Suppl. Table S1). Azithromycin in the doses used in these experiments did not exhibit significant effects on cell viability (Suppl. Fig. S1). These findings outline a specific and dose-dependent impact of azithromycin on the inflammatory caspase axis, leading to the inhibition of IL-1β maturation in human monocytes.

Bottom Line: Interference with Ca(++)-dependent uptake abolished the cytokine-modulatory effect, suggesting a role of intracellular azithromycin accumulation in the modulatory role of this macrolide.Azithromycin's inhibiting effects were observed upon LPS, but not upon flagellin, stimulation.We provide the first evidence of a differential impact of macrolides on the inflammasome/IL-1β axis, which may be of relevance in inflammasome-driven diseases such as chronic obstructive pulmonary disease or asthma.

View Article: PubMed Central - PubMed

Affiliation: Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.

ABSTRACT
Deregulation of inflammasome activation was recently identified to be involved in the pathogenesis of various inflammatory diseases. Although macrolide antibiotics display well described immunomodulatory properties, presumably involved in their clinical effects, their impact on inflammasome activation has not been investigated. We compared the influence of macrolides on cytokine induction in human monocytes. The role of intracellular azithromycin-accumulation was examined by interference with Ca(++)-dependent uptake. We have also analysed the signalling cascades involved in inflammasome activation, and substantiated the findings in a murine sepsis model. Azithromycin, but not clarithromycin or roxithromycin, specifically inhibited IL-1α and IL-1β secretion upon LPS stimulation. Interference with Ca(++)-dependent uptake abolished the cytokine-modulatory effect, suggesting a role of intracellular azithromycin accumulation in the modulatory role of this macrolide. Azithromycin's inhibiting effects were observed upon LPS, but not upon flagellin, stimulation. Consistent with this observation, we found impaired induction of the LPS-sensing caspase-4 whereas NF-κB signalling was unaffected. Furthermore, azithromycin specifically affected IL-1β levels in a murine endotoxin sepsis model. We provide the first evidence of a differential impact of macrolides on the inflammasome/IL-1β axis, which may be of relevance in inflammasome-driven diseases such as chronic obstructive pulmonary disease or asthma.

No MeSH data available.


Related in: MedlinePlus