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Blockage of Eosinopoiesis by IL-17A Is Prevented by Cytokine and Lipid Mediators of Allergic Inflammation.

Xavier-Elsas P, de Luca B, Queto T, Vieira BM, Masid-de-Brito D, Dahab EC, Alves Filho JC, Cunha FQ, Gaspar-Elsas MI - Mediators Inflamm. (2015)

Bottom Line: While IL-17A (0.1-10 ng/mL) had no IL-5-independent effect on eosinopoiesis, it dose-dependently suppressed IL-5-induced eosinophil differentiation, by acting during the initial 24 hours.Its effectiveness was abolished by caspase inhibitor, zVAD-fmk.By contrast, a higher IL-17A concentration (10 ng/mL) retained significant suppressive effect in both conditions, unmasking a high-end iNOS-independent mechanism.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology, Paulo de Góes Institute for Microbiology, Federal University of Rio de Janeiro (UFRJ), 21941-590 Rio de Janeiro, RJ, Brazil.

ABSTRACT
Interleukin- (IL-) 17A, a pleiotropic mediator of inflammation and autoimmunity, potently stimulates bone-marrow neutrophil production. To explore IL-17A effects on eosinopoiesis, we cultured bone-marrow from wild-type mice, or mutants lacking inducible nitric oxide synthase (iNOS-/-), CD95 (lpr), IL-17RA, or IL-4, with IL-5, alone or associated with IL-17A. Synergisms between IL-17A-activated, NO-dependent, and NO-independent mechanisms and antagonisms between IL-17A and proallergic factors were further examined. While IL-17A (0.1-10 ng/mL) had no IL-5-independent effect on eosinopoiesis, it dose-dependently suppressed IL-5-induced eosinophil differentiation, by acting during the initial 24 hours. Its effectiveness was abolished by caspase inhibitor, zVAD-fmk. The effect of IL-17A (0.1-1 ng/mL) was sensitive to the iNOS-selective inhibitor aminoguanidine and undetectable in iNOS-/- bone-marrow. By contrast, a higher IL-17A concentration (10 ng/mL) retained significant suppressive effect in both conditions, unmasking a high-end iNOS-independent mechanism. Lower IL-17A concentrations synergized with NO donor nitroprusside. Eosinopoiesis suppression by IL-17A was (a) undetectable in bone-marrow lacking IL-17RA or CD95 and (b) actively prevented by LTD4, LTC4, IL-13, and eotaxin. Sensitivity to IL-17A was increased in bone-marrow lacking IL-4; adding IL-4 to the cultures restored IL-5 responses to control levels. Therefore, effects of both IL-17A and proallergic factors are transduced by the iNOS-CD95 pathway in isolated bone-marrow.

No MeSH data available.


Related in: MedlinePlus

IL-4 attenuates the suppressive effects of IL-17A on eosinopoiesis. Bone-marrow cultures were established with IL-5, alone or in association with IL-17A, IL-4, or both, from IL-4-deficient mice of the BALB/c background mice, as described in legend of Figure 1. Data (mean + SEM) are the numbers of EPO+ cells recovered at day 7. (a) Concentration-response relationship for IL-17A with significant suppression down to 0.1 ng/mL (comparing with Figure 1(a)). (b) Effect of adding IL-4 in different concentrations to cultures in the absence (white bars) and in the presence (black bars) of IL-17, 1 ng/mL. 2 ng/mL abolished the suppressive response to IL-17A, which is highly effective in the absence of exogenous IL-4. Data are mean ± SEM of the numbers of EPO+ cells recovered at day 7. ∗P < 0.05 for the indicated differences.
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fig5: IL-4 attenuates the suppressive effects of IL-17A on eosinopoiesis. Bone-marrow cultures were established with IL-5, alone or in association with IL-17A, IL-4, or both, from IL-4-deficient mice of the BALB/c background mice, as described in legend of Figure 1. Data (mean + SEM) are the numbers of EPO+ cells recovered at day 7. (a) Concentration-response relationship for IL-17A with significant suppression down to 0.1 ng/mL (comparing with Figure 1(a)). (b) Effect of adding IL-4 in different concentrations to cultures in the absence (white bars) and in the presence (black bars) of IL-17, 1 ng/mL. 2 ng/mL abolished the suppressive response to IL-17A, which is highly effective in the absence of exogenous IL-4. Data are mean ± SEM of the numbers of EPO+ cells recovered at day 7. ∗P < 0.05 for the indicated differences.

Mentions: The ability of cytokine and lipid mediators of allergic inflammation, such as CysLT, eotaxin, and IL-13, to prevent IL-17A actions on eosinopoiesis, in a way consistent with the ability of all these agents to enhance IL-5-dependent eosinopoiesis, prompted us to evaluate whether the prototypical TH2 cytokine, IL-4, which shares signaling mechanisms with IL-13, would act similarly. As shown in Figure 5, bone-marrow from mice lacking IL-4 production had a 10-fold lower threshold for the inhibitory effect of IL-17A (Figure 5(a)) than bone-marrow from WT BALB/c controls (Figure 1(a)). This sensitivity increased by one order of magnitude suggested that IL-4 acts in vivo to attenuate responsiveness to IL-17A. If so, addition of IL-4 in vitro should be able to restore responses to IL-17A in IL-4-deficient bone-marrow back to the level of WT controls. This is indeed confirmed by the data in Figure 5(b): in IL-4-deficient bone-marrow, IL-4 at a relatively low concentration in culture (2 ng/mL) abolished the effectiveness of IL-17A, 1 ng/mL, which in the absence of IL-4 was highly effective. At a higher concentration range (10–30 ng/mL), IL-4 suppressed eosinopoiesis, in a way that was both independent of and unaffected by the presence of IL-17A and possibly represented an unrelated regulatory effect of IL-4.


Blockage of Eosinopoiesis by IL-17A Is Prevented by Cytokine and Lipid Mediators of Allergic Inflammation.

Xavier-Elsas P, de Luca B, Queto T, Vieira BM, Masid-de-Brito D, Dahab EC, Alves Filho JC, Cunha FQ, Gaspar-Elsas MI - Mediators Inflamm. (2015)

IL-4 attenuates the suppressive effects of IL-17A on eosinopoiesis. Bone-marrow cultures were established with IL-5, alone or in association with IL-17A, IL-4, or both, from IL-4-deficient mice of the BALB/c background mice, as described in legend of Figure 1. Data (mean + SEM) are the numbers of EPO+ cells recovered at day 7. (a) Concentration-response relationship for IL-17A with significant suppression down to 0.1 ng/mL (comparing with Figure 1(a)). (b) Effect of adding IL-4 in different concentrations to cultures in the absence (white bars) and in the presence (black bars) of IL-17, 1 ng/mL. 2 ng/mL abolished the suppressive response to IL-17A, which is highly effective in the absence of exogenous IL-4. Data are mean ± SEM of the numbers of EPO+ cells recovered at day 7. ∗P < 0.05 for the indicated differences.
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig5: IL-4 attenuates the suppressive effects of IL-17A on eosinopoiesis. Bone-marrow cultures were established with IL-5, alone or in association with IL-17A, IL-4, or both, from IL-4-deficient mice of the BALB/c background mice, as described in legend of Figure 1. Data (mean + SEM) are the numbers of EPO+ cells recovered at day 7. (a) Concentration-response relationship for IL-17A with significant suppression down to 0.1 ng/mL (comparing with Figure 1(a)). (b) Effect of adding IL-4 in different concentrations to cultures in the absence (white bars) and in the presence (black bars) of IL-17, 1 ng/mL. 2 ng/mL abolished the suppressive response to IL-17A, which is highly effective in the absence of exogenous IL-4. Data are mean ± SEM of the numbers of EPO+ cells recovered at day 7. ∗P < 0.05 for the indicated differences.
Mentions: The ability of cytokine and lipid mediators of allergic inflammation, such as CysLT, eotaxin, and IL-13, to prevent IL-17A actions on eosinopoiesis, in a way consistent with the ability of all these agents to enhance IL-5-dependent eosinopoiesis, prompted us to evaluate whether the prototypical TH2 cytokine, IL-4, which shares signaling mechanisms with IL-13, would act similarly. As shown in Figure 5, bone-marrow from mice lacking IL-4 production had a 10-fold lower threshold for the inhibitory effect of IL-17A (Figure 5(a)) than bone-marrow from WT BALB/c controls (Figure 1(a)). This sensitivity increased by one order of magnitude suggested that IL-4 acts in vivo to attenuate responsiveness to IL-17A. If so, addition of IL-4 in vitro should be able to restore responses to IL-17A in IL-4-deficient bone-marrow back to the level of WT controls. This is indeed confirmed by the data in Figure 5(b): in IL-4-deficient bone-marrow, IL-4 at a relatively low concentration in culture (2 ng/mL) abolished the effectiveness of IL-17A, 1 ng/mL, which in the absence of IL-4 was highly effective. At a higher concentration range (10–30 ng/mL), IL-4 suppressed eosinopoiesis, in a way that was both independent of and unaffected by the presence of IL-17A and possibly represented an unrelated regulatory effect of IL-4.

Bottom Line: While IL-17A (0.1-10 ng/mL) had no IL-5-independent effect on eosinopoiesis, it dose-dependently suppressed IL-5-induced eosinophil differentiation, by acting during the initial 24 hours.Its effectiveness was abolished by caspase inhibitor, zVAD-fmk.By contrast, a higher IL-17A concentration (10 ng/mL) retained significant suppressive effect in both conditions, unmasking a high-end iNOS-independent mechanism.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology, Paulo de Góes Institute for Microbiology, Federal University of Rio de Janeiro (UFRJ), 21941-590 Rio de Janeiro, RJ, Brazil.

ABSTRACT
Interleukin- (IL-) 17A, a pleiotropic mediator of inflammation and autoimmunity, potently stimulates bone-marrow neutrophil production. To explore IL-17A effects on eosinopoiesis, we cultured bone-marrow from wild-type mice, or mutants lacking inducible nitric oxide synthase (iNOS-/-), CD95 (lpr), IL-17RA, or IL-4, with IL-5, alone or associated with IL-17A. Synergisms between IL-17A-activated, NO-dependent, and NO-independent mechanisms and antagonisms between IL-17A and proallergic factors were further examined. While IL-17A (0.1-10 ng/mL) had no IL-5-independent effect on eosinopoiesis, it dose-dependently suppressed IL-5-induced eosinophil differentiation, by acting during the initial 24 hours. Its effectiveness was abolished by caspase inhibitor, zVAD-fmk. The effect of IL-17A (0.1-1 ng/mL) was sensitive to the iNOS-selective inhibitor aminoguanidine and undetectable in iNOS-/- bone-marrow. By contrast, a higher IL-17A concentration (10 ng/mL) retained significant suppressive effect in both conditions, unmasking a high-end iNOS-independent mechanism. Lower IL-17A concentrations synergized with NO donor nitroprusside. Eosinopoiesis suppression by IL-17A was (a) undetectable in bone-marrow lacking IL-17RA or CD95 and (b) actively prevented by LTD4, LTC4, IL-13, and eotaxin. Sensitivity to IL-17A was increased in bone-marrow lacking IL-4; adding IL-4 to the cultures restored IL-5 responses to control levels. Therefore, effects of both IL-17A and proallergic factors are transduced by the iNOS-CD95 pathway in isolated bone-marrow.

No MeSH data available.


Related in: MedlinePlus