Limits...
Paradoxical effects of rapamycin on experimental house dust mite-induced asthma.

Fredriksson K, Fielhaber JA, Lam JK, Yao X, Meyer KS, Keeran KJ, Zywicke GJ, Qu X, Yu ZX, Moss J, Kristof AS, Levine SJ - PLoS ONE (2012)

Bottom Line: Lastly, mediastinal lymph node re-stimulation experiments showed that treatment of rapamycin-naive T cells with ex vivo rapamycin decreased antigen-specific Th2 cytokine production, whereas prior exposure to in vivo rapamycin rendered T cells refractory to the suppressive effects of ex vivo rapamycin.We conclude that rapamycin had paradoxical effects on the pathogenesis of experimental HDM-induced asthma.Thus, consistent with the context-dependent effects of rapamycin on inflammation, the timing of mTOR inhibition may be an important determinant of efficacy and toxicity in HDM-induced asthma.

View Article: PubMed Central - PubMed

Affiliation: Cardiovascular and Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA.

ABSTRACT
The mammalian target of rapamycin (mTOR) modulates immune responses and cellular proliferation. The objective of this study was to assess whether inhibition of mTOR with rapamycin modifies disease severity in two experimental murine models of house dust mite (HDM)-induced asthma. In an induction model, rapamycin was administered to BALB/c mice coincident with nasal HDM challenges for 3 weeks. In a treatment model, nasal HDM challenges were performed for 6 weeks and rapamycin treatment was administered during weeks 4 through 6. In the induction model, rapamycin significantly attenuated airway inflammation, airway hyperreactivity (AHR) and goblet cell hyperplasia. In contrast, treatment of established HDM-induced asthma with rapamycin exacerbated AHR and airway inflammation, whereas goblet cell hyperplasia was not modified. Phosphorylation of the S6 ribosomal protein, which is downstream of mTORC1, was increased after 3 weeks, but not 6 weeks of HDM-challenge. Rapamycin reduced S6 phosphorylation in HDM-challenged mice in both the induction and treatment models. Thus, the paradoxical effects of rapamycin on asthma severity paralleled the activation of mTOR signaling. Lastly, mediastinal lymph node re-stimulation experiments showed that treatment of rapamycin-naive T cells with ex vivo rapamycin decreased antigen-specific Th2 cytokine production, whereas prior exposure to in vivo rapamycin rendered T cells refractory to the suppressive effects of ex vivo rapamycin. We conclude that rapamycin had paradoxical effects on the pathogenesis of experimental HDM-induced asthma. Thus, consistent with the context-dependent effects of rapamycin on inflammation, the timing of mTOR inhibition may be an important determinant of efficacy and toxicity in HDM-induced asthma.

Show MeSH

Related in: MedlinePlus

Effects of Rapamycin on Mediastinal Lymph Node Th2 Cytokine Production.Mediastinal lymph nodes from HDM-challenged mice that had or had not been treated with rapamycin concurrent with HDM stimulation for 3 weeks (induction model) were cultured ex vivo with or without HDM re-stimulation and/or rapamycin. The amount of IL-4, IL-5 and IL-13 released into the medium was quantified by ELISA (* P<0.05, n = 5–6). Results are representative of two independent experiments.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3368343&req=5

pone-0033984-g005: Effects of Rapamycin on Mediastinal Lymph Node Th2 Cytokine Production.Mediastinal lymph nodes from HDM-challenged mice that had or had not been treated with rapamycin concurrent with HDM stimulation for 3 weeks (induction model) were cultured ex vivo with or without HDM re-stimulation and/or rapamycin. The amount of IL-4, IL-5 and IL-13 released into the medium was quantified by ELISA (* P<0.05, n = 5–6). Results are representative of two independent experiments.

Mentions: To investigate further the paradoxical effects of rapamycin on HDM-mediated airway inflammation, we used the induction model to assess the effects of ex vivo rapamycin on antigen-specific Th2 cytokine production by T cells isolated from the draining mediastinal lymph nodes of mice that had previously been sensitized to HDM in vivo with or without rapamycin administered by gavage. HDM re-stimulation of mediastinal lymph node cells recovered from mice that had been challenged with HDM for 3 weeks without in vivo rapamycin treatment showed a significant reduction in the production of the Th2 cytokines, IL-4, IL-5 and IL-13 (Figure 5). This result is consistent with a requirement for mTOR in Th2 cytokine production by HDM-sensitized T cells. Levels of the Th17 cytokine, IL-17A, were below the limit of detection of the assay. In contrast, HDM re-stimulation of mediastinal lymph node cells recovered from HDM-challenged mice that had been treated with rapamycin both in vivo and ex vivo showed no reduction in the production of IL-4, IL-5 or IL-13 as compared to cells that were only treated with rapamycin in vivo. Taken together, this shows that treatment of rapamycin-naive T cells with rapamycin decreases the antigen-specific production of Th2 cytokines, whereas prior exposure of T cells to HDM and rapamycin for 3 weeks in vivo makes them refractory to the suppressive effects of ex vivo rapamycin treatment on HDM-mediated Th2 cytokine production.


Paradoxical effects of rapamycin on experimental house dust mite-induced asthma.

Fredriksson K, Fielhaber JA, Lam JK, Yao X, Meyer KS, Keeran KJ, Zywicke GJ, Qu X, Yu ZX, Moss J, Kristof AS, Levine SJ - PLoS ONE (2012)

Effects of Rapamycin on Mediastinal Lymph Node Th2 Cytokine Production.Mediastinal lymph nodes from HDM-challenged mice that had or had not been treated with rapamycin concurrent with HDM stimulation for 3 weeks (induction model) were cultured ex vivo with or without HDM re-stimulation and/or rapamycin. The amount of IL-4, IL-5 and IL-13 released into the medium was quantified by ELISA (* P<0.05, n = 5–6). Results are representative of two independent experiments.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3368343&req=5

pone-0033984-g005: Effects of Rapamycin on Mediastinal Lymph Node Th2 Cytokine Production.Mediastinal lymph nodes from HDM-challenged mice that had or had not been treated with rapamycin concurrent with HDM stimulation for 3 weeks (induction model) were cultured ex vivo with or without HDM re-stimulation and/or rapamycin. The amount of IL-4, IL-5 and IL-13 released into the medium was quantified by ELISA (* P<0.05, n = 5–6). Results are representative of two independent experiments.
Mentions: To investigate further the paradoxical effects of rapamycin on HDM-mediated airway inflammation, we used the induction model to assess the effects of ex vivo rapamycin on antigen-specific Th2 cytokine production by T cells isolated from the draining mediastinal lymph nodes of mice that had previously been sensitized to HDM in vivo with or without rapamycin administered by gavage. HDM re-stimulation of mediastinal lymph node cells recovered from mice that had been challenged with HDM for 3 weeks without in vivo rapamycin treatment showed a significant reduction in the production of the Th2 cytokines, IL-4, IL-5 and IL-13 (Figure 5). This result is consistent with a requirement for mTOR in Th2 cytokine production by HDM-sensitized T cells. Levels of the Th17 cytokine, IL-17A, were below the limit of detection of the assay. In contrast, HDM re-stimulation of mediastinal lymph node cells recovered from HDM-challenged mice that had been treated with rapamycin both in vivo and ex vivo showed no reduction in the production of IL-4, IL-5 or IL-13 as compared to cells that were only treated with rapamycin in vivo. Taken together, this shows that treatment of rapamycin-naive T cells with rapamycin decreases the antigen-specific production of Th2 cytokines, whereas prior exposure of T cells to HDM and rapamycin for 3 weeks in vivo makes them refractory to the suppressive effects of ex vivo rapamycin treatment on HDM-mediated Th2 cytokine production.

Bottom Line: Lastly, mediastinal lymph node re-stimulation experiments showed that treatment of rapamycin-naive T cells with ex vivo rapamycin decreased antigen-specific Th2 cytokine production, whereas prior exposure to in vivo rapamycin rendered T cells refractory to the suppressive effects of ex vivo rapamycin.We conclude that rapamycin had paradoxical effects on the pathogenesis of experimental HDM-induced asthma.Thus, consistent with the context-dependent effects of rapamycin on inflammation, the timing of mTOR inhibition may be an important determinant of efficacy and toxicity in HDM-induced asthma.

View Article: PubMed Central - PubMed

Affiliation: Cardiovascular and Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA.

ABSTRACT
The mammalian target of rapamycin (mTOR) modulates immune responses and cellular proliferation. The objective of this study was to assess whether inhibition of mTOR with rapamycin modifies disease severity in two experimental murine models of house dust mite (HDM)-induced asthma. In an induction model, rapamycin was administered to BALB/c mice coincident with nasal HDM challenges for 3 weeks. In a treatment model, nasal HDM challenges were performed for 6 weeks and rapamycin treatment was administered during weeks 4 through 6. In the induction model, rapamycin significantly attenuated airway inflammation, airway hyperreactivity (AHR) and goblet cell hyperplasia. In contrast, treatment of established HDM-induced asthma with rapamycin exacerbated AHR and airway inflammation, whereas goblet cell hyperplasia was not modified. Phosphorylation of the S6 ribosomal protein, which is downstream of mTORC1, was increased after 3 weeks, but not 6 weeks of HDM-challenge. Rapamycin reduced S6 phosphorylation in HDM-challenged mice in both the induction and treatment models. Thus, the paradoxical effects of rapamycin on asthma severity paralleled the activation of mTOR signaling. Lastly, mediastinal lymph node re-stimulation experiments showed that treatment of rapamycin-naive T cells with ex vivo rapamycin decreased antigen-specific Th2 cytokine production, whereas prior exposure to in vivo rapamycin rendered T cells refractory to the suppressive effects of ex vivo rapamycin. We conclude that rapamycin had paradoxical effects on the pathogenesis of experimental HDM-induced asthma. Thus, consistent with the context-dependent effects of rapamycin on inflammation, the timing of mTOR inhibition may be an important determinant of efficacy and toxicity in HDM-induced asthma.

Show MeSH
Related in: MedlinePlus