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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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IL-4–induced Arg1 expression in BMDMs is dependent on the type I IL-4 receptor and Stat6 expression. (A) BMDMs from WT and γc−/− mice prepared as in Fig. 1 A were unstimulated or stimulated with indicated concentrations of IL-4 or -13 for 2 h. Cells were lysed, RNA was purified and transcribed to cDNA, and RT-PCR performed to measure Arg1 expression. The results were normalized to 18S RNA. The experiment was performed independently three times; means and SEMs of results from the individual experiments are shown. (B) BMDMs were prepared from Stat6-deficient B6 mouse and left untreated or treated with indicated concentrations of IL-4 or IL-13. Thereafter, the experiment was performed as in A. The experiment was performed independently three times; means and SEMs of results from the individual experiments are shown. (C) BMDMs from WT and γc−/− mice treated for 1 h at 37°C with blocking antibody against IL-4Rα (M1) as indicated, followed by stimulation with IL-4 or -13 (10 and 200 ng/ml, respectively) for 2 h. Cells were lysed and Arg1 mRNA induction measured as in A.
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fig2: IL-4–induced Arg1 expression in BMDMs is dependent on the type I IL-4 receptor and Stat6 expression. (A) BMDMs from WT and γc−/− mice prepared as in Fig. 1 A were unstimulated or stimulated with indicated concentrations of IL-4 or -13 for 2 h. Cells were lysed, RNA was purified and transcribed to cDNA, and RT-PCR performed to measure Arg1 expression. The results were normalized to 18S RNA. The experiment was performed independently three times; means and SEMs of results from the individual experiments are shown. (B) BMDMs were prepared from Stat6-deficient B6 mouse and left untreated or treated with indicated concentrations of IL-4 or IL-13. Thereafter, the experiment was performed as in A. The experiment was performed independently three times; means and SEMs of results from the individual experiments are shown. (C) BMDMs from WT and γc−/− mice treated for 1 h at 37°C with blocking antibody against IL-4Rα (M1) as indicated, followed by stimulation with IL-4 or -13 (10 and 200 ng/ml, respectively) for 2 h. Cells were lysed and Arg1 mRNA induction measured as in A.

Mentions: Type II macrophage activation results in induction of several genes, including arginase (Arg) 1. Arg1 plays an important role in regulating macrophage responses, as Arg1 decreases nitric oxide synthase production, and thus nitric oxide, by consuming the substrate, cellular l-arginine (22). The promoter of Arg1 contains a Stat6 binding site (23), and Arg1 mRNA is induced in mouse macrophages by IL-4 (24). As shown in Fig. 2 A, Arg1 mRNA induction at 2 h could be detected in response to 1 ng/ml of IL-4, and peaked at 10 ng/ml (mean of fold induction, 247). In contrast, IL-13 at <10 ng/ml did not induce detectable Arg1, and its peak induction (mean of fold induction, 79) was only ∼30% of the levels induced by IL-4 (Fig. 2 A). In γc−/− BMDMs, IL-13 induction of Arg1 was comparable to that observed in WT BMDMs, but IL-4 induction of Arg1 was virtually undetectable, even at 100 ng/ml (Fig. 2 A). Anti–IL-4Rα (M1) inhibited IL-13-induced Arg1 expression in both WT and γc−/− BMDMs, confirming that IL-13 responses require the IL-4 receptor-α chain (Fig. 2 C) and that the IL-13 response could not be attributed to a non–IL-4Rα–using receptor. The importance of Stat6 in the response to both IL-4 and -13 was demonstrated by the failure of both cytokines to induce Arg1 expression, even at 100 ng/ml in Stat6−/− BMDMs (Fig. 2 B).


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)

IL-4–induced Arg1 expression in BMDMs is dependent on the type I IL-4 receptor and Stat6 expression. (A) BMDMs from WT and γc−/− mice prepared as in Fig. 1 A were unstimulated or stimulated with indicated concentrations of IL-4 or -13 for 2 h. Cells were lysed, RNA was purified and transcribed to cDNA, and RT-PCR performed to measure Arg1 expression. The results were normalized to 18S RNA. The experiment was performed independently three times; means and SEMs of results from the individual experiments are shown. (B) BMDMs were prepared from Stat6-deficient B6 mouse and left untreated or treated with indicated concentrations of IL-4 or IL-13. Thereafter, the experiment was performed as in A. The experiment was performed independently three times; means and SEMs of results from the individual experiments are shown. (C) BMDMs from WT and γc−/− mice treated for 1 h at 37°C with blocking antibody against IL-4Rα (M1) as indicated, followed by stimulation with IL-4 or -13 (10 and 200 ng/ml, respectively) for 2 h. Cells were lysed and Arg1 mRNA induction measured as in A.
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fig2: IL-4–induced Arg1 expression in BMDMs is dependent on the type I IL-4 receptor and Stat6 expression. (A) BMDMs from WT and γc−/− mice prepared as in Fig. 1 A were unstimulated or stimulated with indicated concentrations of IL-4 or -13 for 2 h. Cells were lysed, RNA was purified and transcribed to cDNA, and RT-PCR performed to measure Arg1 expression. The results were normalized to 18S RNA. The experiment was performed independently three times; means and SEMs of results from the individual experiments are shown. (B) BMDMs were prepared from Stat6-deficient B6 mouse and left untreated or treated with indicated concentrations of IL-4 or IL-13. Thereafter, the experiment was performed as in A. The experiment was performed independently three times; means and SEMs of results from the individual experiments are shown. (C) BMDMs from WT and γc−/− mice treated for 1 h at 37°C with blocking antibody against IL-4Rα (M1) as indicated, followed by stimulation with IL-4 or -13 (10 and 200 ng/ml, respectively) for 2 h. Cells were lysed and Arg1 mRNA induction measured as in A.
Mentions: Type II macrophage activation results in induction of several genes, including arginase (Arg) 1. Arg1 plays an important role in regulating macrophage responses, as Arg1 decreases nitric oxide synthase production, and thus nitric oxide, by consuming the substrate, cellular l-arginine (22). The promoter of Arg1 contains a Stat6 binding site (23), and Arg1 mRNA is induced in mouse macrophages by IL-4 (24). As shown in Fig. 2 A, Arg1 mRNA induction at 2 h could be detected in response to 1 ng/ml of IL-4, and peaked at 10 ng/ml (mean of fold induction, 247). In contrast, IL-13 at <10 ng/ml did not induce detectable Arg1, and its peak induction (mean of fold induction, 79) was only ∼30% of the levels induced by IL-4 (Fig. 2 A). In γc−/− BMDMs, IL-13 induction of Arg1 was comparable to that observed in WT BMDMs, but IL-4 induction of Arg1 was virtually undetectable, even at 100 ng/ml (Fig. 2 A). Anti–IL-4Rα (M1) inhibited IL-13-induced Arg1 expression in both WT and γc−/− BMDMs, confirming that IL-13 responses require the IL-4 receptor-α chain (Fig. 2 C) and that the IL-13 response could not be attributed to a non–IL-4Rα–using receptor. The importance of Stat6 in the response to both IL-4 and -13 was demonstrated by the failure of both cytokines to induce Arg1 expression, even at 100 ng/ml in Stat6−/− BMDMs (Fig. 2 B).

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
Related in: MedlinePlus