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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

Interference with Ca++-dependent intracellular azithromycin accumulation abrogates the cytokine-modulating effect.Panel a) shows the impact of azithromycin on LPS stimulated human monocytes in the presence of 10 mM EGTA. Panel b) shows the impact of azithromycin IL-1β production of verapamil pretreated (30 min) and LPS stimulated monocytes in the presence verapamil. Cells were treated with the indicated concentrations of azithromycin and stimulated with 100 ng/ml LPS 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 3 independent experiments.
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f3: Interference with Ca++-dependent intracellular azithromycin accumulation abrogates the cytokine-modulating effect.Panel a) shows the impact of azithromycin on LPS stimulated human monocytes in the presence of 10 mM EGTA. Panel b) shows the impact of azithromycin IL-1β production of verapamil pretreated (30 min) and LPS stimulated monocytes in the presence verapamil. Cells were treated with the indicated concentrations of azithromycin and stimulated with 100 ng/ml LPS 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 3 independent experiments.

Mentions: Azithromycin is known to accumulate in leucocytes to a considerably higher degree than any other macrolide antibiotic2829. Drug transport through the plasma membrane (and thus intracellular accumulation) is Ca++-dependent and is assumedly operated via Ca++-channels3031. We hypothesized that differences in intracellular accumulation were responsible for the diverging results observed in our study. To test this hypothesis, we disrupted the transmembrane transport of azithromycin by depleting extracellular calcium as well as utilising the L-type Ca++-channel blocker verapamil, two approaches shown to inhibit macrolide uptake in leucocytes3031. As expected, both strategies interfering with azithromycin uptake resulted in the abrogation of its IL-1β modulating effect (Fig. 3a,b, Suppl. Table S1). These findings suggest a role of intracellular azithromycin accumulation in the modulatory effects of this macrolide which might be of relevance for the differential effects among macrolides.


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)

Interference with Ca++-dependent intracellular azithromycin accumulation abrogates the cytokine-modulating effect.Panel a) shows the impact of azithromycin on LPS stimulated human monocytes in the presence of 10 mM EGTA. Panel b) shows the impact of azithromycin IL-1β production of verapamil pretreated (30 min) and LPS stimulated monocytes in the presence verapamil. Cells were treated with the indicated concentrations of azithromycin and stimulated with 100 ng/ml LPS 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 3 independent experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f3: Interference with Ca++-dependent intracellular azithromycin accumulation abrogates the cytokine-modulating effect.Panel a) shows the impact of azithromycin on LPS stimulated human monocytes in the presence of 10 mM EGTA. Panel b) shows the impact of azithromycin IL-1β production of verapamil pretreated (30 min) and LPS stimulated monocytes in the presence verapamil. Cells were treated with the indicated concentrations of azithromycin and stimulated with 100 ng/ml LPS 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 3 independent experiments.
Mentions: Azithromycin is known to accumulate in leucocytes to a considerably higher degree than any other macrolide antibiotic2829. Drug transport through the plasma membrane (and thus intracellular accumulation) is Ca++-dependent and is assumedly operated via Ca++-channels3031. We hypothesized that differences in intracellular accumulation were responsible for the diverging results observed in our study. To test this hypothesis, we disrupted the transmembrane transport of azithromycin by depleting extracellular calcium as well as utilising the L-type Ca++-channel blocker verapamil, two approaches shown to inhibit macrolide uptake in leucocytes3031. As expected, both strategies interfering with azithromycin uptake resulted in the abrogation of its IL-1β modulating effect (Fig. 3a,b, Suppl. Table S1). These findings suggest a role of intracellular azithromycin accumulation in the modulatory effects of this macrolide which might be of relevance for the differential effects among macrolides.

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