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Tuning sensitivity to IL-4 and IL-13: differential expression of IL-4Ralpha, IL-13Ralpha1, and gammac regulates relative cytokine sensitivity.

Junttila IS, Mizukami K, Dickensheets H, Meier-Schellersheim M, Yamane H, Donnelly RP, Paul WE - J. Exp. Med. (2008)

Bottom Line: In contrast, IL-13 stimulated greater responses than IL-4 in fibroblasts.The differential expression of IL-4Ralpha, IL-13Ralpha1, and gammac accounted for the distinct IL-4-IL-13 sensitivities of the various cell types.These findings provide an explanation for IL-13's principal function as an "effector" cytokine and IL-4's principal role as an "immunoregulatory" cytokine.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA. junttilai@niaid.nih.gov

ABSTRACT
Interleukin (IL)-4 and -13 are related cytokines sharing functional receptors. IL-4 signals through the type I (IL-4Ralpha/common gamma-chain [gammac]) and the type II (IL-4Ralpha/-13Ralpha1) IL-4 receptors, whereas IL-13 utilizes only the type II receptor. In this study, we show that mouse bone marrow-derived macrophages and human and mouse monocytes showed a much greater sensitivity to IL-4 than to IL-13. Lack of functional gammac made these cells poorly responsive to IL-4, while retaining full responsiveness to IL-13. In mouse peritoneal macrophages, IL-4 potency exceeds that of IL-13, but lack of gammac had only a modest effect on IL-4 signaling. In contrast, IL-13 stimulated greater responses than IL-4 in fibroblasts. Using levels of receptor chain expression and known binding affinities, we modeled the assemblage of functional type I and II receptor complexes. The differential expression of IL-4Ralpha, IL-13Ralpha1, and gammac accounted for the distinct IL-4-IL-13 sensitivities of the various cell types. These findings provide an explanation for IL-13's principal function as an "effector" cytokine and IL-4's principal role as an "immunoregulatory" cytokine.

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The Type I IL-4 receptor is essential for responses to low concentrations of IL-4 responses in mouse monocytes. (A) Blood leukocytes were obtained from three to four WT B6 mice. After lysing erythrocytes, the cells were rested in 2% FBS containing medium for 2 h, and then stimulated for 15 min with indicated concentrations of IL-4 and -13 or left unstimulated. Subsequently, the cells were stained for CD11b and F4/80, followed by permeabilization and staining for Y641 of Stat6. The Stat6 phosphorylation of CD11b+ and F4/80+ cells was evaluated as in Fig. 1 A. To study the effect of IL-4 and -13 on blood monocytes in γc−/− mice (B), identical experiments were performed in these mice. A representative experiment is illustrated by the flow cytometry plots; the plot of cytokine concentration versus Δ Median represents data from three independent experiments; the mean and SEM of the results from these independent experiments are shown.
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fig4: The Type I IL-4 receptor is essential for responses to low concentrations of IL-4 responses in mouse monocytes. (A) Blood leukocytes were obtained from three to four WT B6 mice. After lysing erythrocytes, the cells were rested in 2% FBS containing medium for 2 h, and then stimulated for 15 min with indicated concentrations of IL-4 and -13 or left unstimulated. Subsequently, the cells were stained for CD11b and F4/80, followed by permeabilization and staining for Y641 of Stat6. The Stat6 phosphorylation of CD11b+ and F4/80+ cells was evaluated as in Fig. 1 A. To study the effect of IL-4 and -13 on blood monocytes in γc−/− mice (B), identical experiments were performed in these mice. A representative experiment is illustrated by the flow cytometry plots; the plot of cytokine concentration versus Δ Median represents data from three independent experiments; the mean and SEM of the results from these independent experiments are shown.

Mentions: Monocytes are macrophage precursors that circulate in blood. They are released into the bloodstream upon differentiation of the common myeloid progenitor cells in BM (25). Because we hypothesized that BMDMs might represent a relatively immature macrophage pool, we wished to determine whether there are differences in IL-4– and IL-13–induced signaling in these macrophage precursors that would be similar to the differences we detected in BMDMs. Mouse blood monocytes from WT B6 mice were analyzed for responsiveness to IL-4 and -13 by measuring Stat6 Y641 phosphorylation by flow cytometry. IL-4 induced substantial responses at 0.1 ng/ml in monocytes, whereas IL-13 required 10 ng/ml to obtain measureable responses (Fig. 4 A). Because of limitations in cell numbers, we did not test responsiveness to 1 ng/ml or 100 ng/ml of either IL-4 or -13. Monocytes from γc−/− mice responded poorly to both IL-4 and -13 at 0.1 ng/ml, and slightly better to IL-13 than to IL-4 at 10 ng/ml (Fig. 4 B). Thus, the IL-4 sensitivity of γc−/− monocytes resembled that of γc−/− BMDMs.


Tuning sensitivity to IL-4 and IL-13: differential expression of IL-4Ralpha, IL-13Ralpha1, and gammac regulates relative cytokine sensitivity.

Junttila IS, Mizukami K, Dickensheets H, Meier-Schellersheim M, Yamane H, Donnelly RP, Paul WE - J. Exp. Med. (2008)

The Type I IL-4 receptor is essential for responses to low concentrations of IL-4 responses in mouse monocytes. (A) Blood leukocytes were obtained from three to four WT B6 mice. After lysing erythrocytes, the cells were rested in 2% FBS containing medium for 2 h, and then stimulated for 15 min with indicated concentrations of IL-4 and -13 or left unstimulated. Subsequently, the cells were stained for CD11b and F4/80, followed by permeabilization and staining for Y641 of Stat6. The Stat6 phosphorylation of CD11b+ and F4/80+ cells was evaluated as in Fig. 1 A. To study the effect of IL-4 and -13 on blood monocytes in γc−/− mice (B), identical experiments were performed in these mice. A representative experiment is illustrated by the flow cytometry plots; the plot of cytokine concentration versus Δ Median represents data from three independent experiments; the mean and SEM of the results from these independent experiments are shown.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2571934&req=5

fig4: The Type I IL-4 receptor is essential for responses to low concentrations of IL-4 responses in mouse monocytes. (A) Blood leukocytes were obtained from three to four WT B6 mice. After lysing erythrocytes, the cells were rested in 2% FBS containing medium for 2 h, and then stimulated for 15 min with indicated concentrations of IL-4 and -13 or left unstimulated. Subsequently, the cells were stained for CD11b and F4/80, followed by permeabilization and staining for Y641 of Stat6. The Stat6 phosphorylation of CD11b+ and F4/80+ cells was evaluated as in Fig. 1 A. To study the effect of IL-4 and -13 on blood monocytes in γc−/− mice (B), identical experiments were performed in these mice. A representative experiment is illustrated by the flow cytometry plots; the plot of cytokine concentration versus Δ Median represents data from three independent experiments; the mean and SEM of the results from these independent experiments are shown.
Mentions: Monocytes are macrophage precursors that circulate in blood. They are released into the bloodstream upon differentiation of the common myeloid progenitor cells in BM (25). Because we hypothesized that BMDMs might represent a relatively immature macrophage pool, we wished to determine whether there are differences in IL-4– and IL-13–induced signaling in these macrophage precursors that would be similar to the differences we detected in BMDMs. Mouse blood monocytes from WT B6 mice were analyzed for responsiveness to IL-4 and -13 by measuring Stat6 Y641 phosphorylation by flow cytometry. IL-4 induced substantial responses at 0.1 ng/ml in monocytes, whereas IL-13 required 10 ng/ml to obtain measureable responses (Fig. 4 A). Because of limitations in cell numbers, we did not test responsiveness to 1 ng/ml or 100 ng/ml of either IL-4 or -13. Monocytes from γc−/− mice responded poorly to both IL-4 and -13 at 0.1 ng/ml, and slightly better to IL-13 than to IL-4 at 10 ng/ml (Fig. 4 B). Thus, the IL-4 sensitivity of γc−/− monocytes resembled that of γc−/− BMDMs.

Bottom Line: In contrast, IL-13 stimulated greater responses than IL-4 in fibroblasts.The differential expression of IL-4Ralpha, IL-13Ralpha1, and gammac accounted for the distinct IL-4-IL-13 sensitivities of the various cell types.These findings provide an explanation for IL-13's principal function as an "effector" cytokine and IL-4's principal role as an "immunoregulatory" cytokine.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA. junttilai@niaid.nih.gov

ABSTRACT
Interleukin (IL)-4 and -13 are related cytokines sharing functional receptors. IL-4 signals through the type I (IL-4Ralpha/common gamma-chain [gammac]) and the type II (IL-4Ralpha/-13Ralpha1) IL-4 receptors, whereas IL-13 utilizes only the type II receptor. In this study, we show that mouse bone marrow-derived macrophages and human and mouse monocytes showed a much greater sensitivity to IL-4 than to IL-13. Lack of functional gammac made these cells poorly responsive to IL-4, while retaining full responsiveness to IL-13. In mouse peritoneal macrophages, IL-4 potency exceeds that of IL-13, but lack of gammac had only a modest effect on IL-4 signaling. In contrast, IL-13 stimulated greater responses than IL-4 in fibroblasts. Using levels of receptor chain expression and known binding affinities, we modeled the assemblage of functional type I and II receptor complexes. The differential expression of IL-4Ralpha, IL-13Ralpha1, and gammac accounted for the distinct IL-4-IL-13 sensitivities of the various cell types. These findings provide an explanation for IL-13's principal function as an "effector" cytokine and IL-4's principal role as an "immunoregulatory" cytokine.

Show MeSH