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IL-21-mediated non-canonical pathway for IL-1β production in conventional dendritic cells.

Wan CK, Li P, Spolski R, Oh J, Andraski AB, Du N, Yu ZX, Dillon CP, Green DR, Leonard WJ - Nat Commun (2015)

Bottom Line: IL-21 does not induce Il1b expression in CD4(+) T cells, with differential histone marks present in these cells versus cDCs.IL-21-induced IL-1β processing in cDCs does not require caspase-1 or caspase-8 but depends on IL-21-mediated death and activation of serine protease(s).These results demonstrate lineage-restricted IL-21-induced IL-1β via a non-canonical pathway and provide evidence for its importance in vivo.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Molecular Immunology and the Immunology Center, National Heart, Lung and Blood Institute, National Institutes of Health, 10 Center Drive, Building 10, Room 7B05, Bethesda, Maryland 20892-1674 USA.

ABSTRACT
The canonical pathway for IL-1β production requires TLR-mediated NF-κB-dependent Il1b gene induction, followed by caspase-containing inflammasome-mediated processing of pro-IL-1β. Here we show that IL-21 unexpectedly induces IL-1β production in conventional dendritic cells (cDCs) via a STAT3-dependent but NF-κB-independent pathway. IL-21 does not induce Il1b expression in CD4(+) T cells, with differential histone marks present in these cells versus cDCs. IL-21-induced IL-1β processing in cDCs does not require caspase-1 or caspase-8 but depends on IL-21-mediated death and activation of serine protease(s). Moreover, STAT3-dependent IL-1β expression in cDCs at least partially explains the IL-21-mediated pathologic response occurring during infection with pneumonia virus of mice. These results demonstrate lineage-restricted IL-21-induced IL-1β via a non-canonical pathway and provide evidence for its importance in vivo.

No MeSH data available.


Related in: MedlinePlus

IL-21-STAT3 signaling contributes to the expression of IL-1β during PVM infection.(a,b) Il21r+/+ and Il21r−/− mice were infected with 60 plaque-forming unit PVM for 6 days. Expression of intracellular pro-IL-1β in DCs (CD11c+MHCII+F4/80−) was determined by flow cytometry. Shown are representative plots (a) and summary of data from multiple animals (b). Data from two experiments (n=6). (c–f) Stat3+/+ and Stat3−/− mice were infected with 60 plaque-forming unit PVM for 6 days. (c) RNA was isolated from lungs and Il1b mRNA expression was analysed by RT–PCR. (d–f) Expression of intracellular pro-IL-1β in DCs (CD11c+MHCII+F4/80−) (b,c) and macrophages (CD11c+MHCII+F4/80+) (b,d) was determined by flow cytometry. Shown are representative plots (d) and summary of data of DCs (e) and macrophages (f) from multiple animals. Data are from two experiments (Stat3+/+, n=9; Stat3−/−, n=7). In f, NS, P=0.26. (g,h) Il1r+/+ and Il1r−/− mice were infected with PVM as in a. (g) Representative lung sections (stained with H&E) from Il1r+/+ and Il1r−/− mice after PVM infection for 6 days. Top: Compared with Il1r−/− mice, Il1r+/+ lungs showing severe oedema at day 6 after PVM infection. Bottom: higher magnification; neutrophils (black arrows), macrophages (red arrow) and lymphocytes (blue arrow). (h) Percent neutrophils (CD11bhi Ly6G+, determined by flow cytometry) in lungs after PVM infection for 6 days. Data are from two experiments (total of eight mice per group). Statistical analysis was performed by Student's t-test.
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f8: IL-21-STAT3 signaling contributes to the expression of IL-1β during PVM infection.(a,b) Il21r+/+ and Il21r−/− mice were infected with 60 plaque-forming unit PVM for 6 days. Expression of intracellular pro-IL-1β in DCs (CD11c+MHCII+F4/80−) was determined by flow cytometry. Shown are representative plots (a) and summary of data from multiple animals (b). Data from two experiments (n=6). (c–f) Stat3+/+ and Stat3−/− mice were infected with 60 plaque-forming unit PVM for 6 days. (c) RNA was isolated from lungs and Il1b mRNA expression was analysed by RT–PCR. (d–f) Expression of intracellular pro-IL-1β in DCs (CD11c+MHCII+F4/80−) (b,c) and macrophages (CD11c+MHCII+F4/80+) (b,d) was determined by flow cytometry. Shown are representative plots (d) and summary of data of DCs (e) and macrophages (f) from multiple animals. Data are from two experiments (Stat3+/+, n=9; Stat3−/−, n=7). In f, NS, P=0.26. (g,h) Il1r+/+ and Il1r−/− mice were infected with PVM as in a. (g) Representative lung sections (stained with H&E) from Il1r+/+ and Il1r−/− mice after PVM infection for 6 days. Top: Compared with Il1r−/− mice, Il1r+/+ lungs showing severe oedema at day 6 after PVM infection. Bottom: higher magnification; neutrophils (black arrows), macrophages (red arrow) and lymphocytes (blue arrow). (h) Percent neutrophils (CD11bhi Ly6G+, determined by flow cytometry) in lungs after PVM infection for 6 days. Data are from two experiments (total of eight mice per group). Statistical analysis was performed by Student's t-test.

Mentions: IL-21 promotes the pathological immune response of PVM but the mechanism is unclear. We found less Il1b mRNA in the lungs of Il21r−/− mice than in wild-type (WT) mice after infection with PVM27. Correspondingly, cDCs from Il21r−/− mice had lower expression of pro-IL-1β after PVM infection (Fig. 8a,b). Consistent with the role of STAT3 in IL-21-mediated IL-1β expression, Il1b mRNA was also lower in lungs from Stat3−/− than from WT mice after PVM infection (Fig. 8c). The absence of STAT3 significantly lowered pro-IL-1β expression in cDCs (Fig. 8d,e), whereas pro-IL-1β production tended to be lower in macrophages, although the decrease was not statistically significant (Fig. 8d,f), analogous to the in vitro data (Fig. 2f). Moreover, Il1r-deficient mice had less perivascular oedema and fewer immune cells (Fig. 8g, right versus left panel), and particularly fewer neutrophils (Fig. 8h) in the lung. These results indicate that IL-1β is a key mediator of inflammation, and collectively indicate the importance of the IL-21-STAT3-IL-β axis in the pathological immune response to PVM infection.


IL-21-mediated non-canonical pathway for IL-1β production in conventional dendritic cells.

Wan CK, Li P, Spolski R, Oh J, Andraski AB, Du N, Yu ZX, Dillon CP, Green DR, Leonard WJ - Nat Commun (2015)

IL-21-STAT3 signaling contributes to the expression of IL-1β during PVM infection.(a,b) Il21r+/+ and Il21r−/− mice were infected with 60 plaque-forming unit PVM for 6 days. Expression of intracellular pro-IL-1β in DCs (CD11c+MHCII+F4/80−) was determined by flow cytometry. Shown are representative plots (a) and summary of data from multiple animals (b). Data from two experiments (n=6). (c–f) Stat3+/+ and Stat3−/− mice were infected with 60 plaque-forming unit PVM for 6 days. (c) RNA was isolated from lungs and Il1b mRNA expression was analysed by RT–PCR. (d–f) Expression of intracellular pro-IL-1β in DCs (CD11c+MHCII+F4/80−) (b,c) and macrophages (CD11c+MHCII+F4/80+) (b,d) was determined by flow cytometry. Shown are representative plots (d) and summary of data of DCs (e) and macrophages (f) from multiple animals. Data are from two experiments (Stat3+/+, n=9; Stat3−/−, n=7). In f, NS, P=0.26. (g,h) Il1r+/+ and Il1r−/− mice were infected with PVM as in a. (g) Representative lung sections (stained with H&E) from Il1r+/+ and Il1r−/− mice after PVM infection for 6 days. Top: Compared with Il1r−/− mice, Il1r+/+ lungs showing severe oedema at day 6 after PVM infection. Bottom: higher magnification; neutrophils (black arrows), macrophages (red arrow) and lymphocytes (blue arrow). (h) Percent neutrophils (CD11bhi Ly6G+, determined by flow cytometry) in lungs after PVM infection for 6 days. Data are from two experiments (total of eight mice per group). Statistical analysis was performed by Student's t-test.
© Copyright Policy - open-access
Related In: Results  -  Collection

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f8: IL-21-STAT3 signaling contributes to the expression of IL-1β during PVM infection.(a,b) Il21r+/+ and Il21r−/− mice were infected with 60 plaque-forming unit PVM for 6 days. Expression of intracellular pro-IL-1β in DCs (CD11c+MHCII+F4/80−) was determined by flow cytometry. Shown are representative plots (a) and summary of data from multiple animals (b). Data from two experiments (n=6). (c–f) Stat3+/+ and Stat3−/− mice were infected with 60 plaque-forming unit PVM for 6 days. (c) RNA was isolated from lungs and Il1b mRNA expression was analysed by RT–PCR. (d–f) Expression of intracellular pro-IL-1β in DCs (CD11c+MHCII+F4/80−) (b,c) and macrophages (CD11c+MHCII+F4/80+) (b,d) was determined by flow cytometry. Shown are representative plots (d) and summary of data of DCs (e) and macrophages (f) from multiple animals. Data are from two experiments (Stat3+/+, n=9; Stat3−/−, n=7). In f, NS, P=0.26. (g,h) Il1r+/+ and Il1r−/− mice were infected with PVM as in a. (g) Representative lung sections (stained with H&E) from Il1r+/+ and Il1r−/− mice after PVM infection for 6 days. Top: Compared with Il1r−/− mice, Il1r+/+ lungs showing severe oedema at day 6 after PVM infection. Bottom: higher magnification; neutrophils (black arrows), macrophages (red arrow) and lymphocytes (blue arrow). (h) Percent neutrophils (CD11bhi Ly6G+, determined by flow cytometry) in lungs after PVM infection for 6 days. Data are from two experiments (total of eight mice per group). Statistical analysis was performed by Student's t-test.
Mentions: IL-21 promotes the pathological immune response of PVM but the mechanism is unclear. We found less Il1b mRNA in the lungs of Il21r−/− mice than in wild-type (WT) mice after infection with PVM27. Correspondingly, cDCs from Il21r−/− mice had lower expression of pro-IL-1β after PVM infection (Fig. 8a,b). Consistent with the role of STAT3 in IL-21-mediated IL-1β expression, Il1b mRNA was also lower in lungs from Stat3−/− than from WT mice after PVM infection (Fig. 8c). The absence of STAT3 significantly lowered pro-IL-1β expression in cDCs (Fig. 8d,e), whereas pro-IL-1β production tended to be lower in macrophages, although the decrease was not statistically significant (Fig. 8d,f), analogous to the in vitro data (Fig. 2f). Moreover, Il1r-deficient mice had less perivascular oedema and fewer immune cells (Fig. 8g, right versus left panel), and particularly fewer neutrophils (Fig. 8h) in the lung. These results indicate that IL-1β is a key mediator of inflammation, and collectively indicate the importance of the IL-21-STAT3-IL-β axis in the pathological immune response to PVM infection.

Bottom Line: IL-21 does not induce Il1b expression in CD4(+) T cells, with differential histone marks present in these cells versus cDCs.IL-21-induced IL-1β processing in cDCs does not require caspase-1 or caspase-8 but depends on IL-21-mediated death and activation of serine protease(s).These results demonstrate lineage-restricted IL-21-induced IL-1β via a non-canonical pathway and provide evidence for its importance in vivo.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Molecular Immunology and the Immunology Center, National Heart, Lung and Blood Institute, National Institutes of Health, 10 Center Drive, Building 10, Room 7B05, Bethesda, Maryland 20892-1674 USA.

ABSTRACT
The canonical pathway for IL-1β production requires TLR-mediated NF-κB-dependent Il1b gene induction, followed by caspase-containing inflammasome-mediated processing of pro-IL-1β. Here we show that IL-21 unexpectedly induces IL-1β production in conventional dendritic cells (cDCs) via a STAT3-dependent but NF-κB-independent pathway. IL-21 does not induce Il1b expression in CD4(+) T cells, with differential histone marks present in these cells versus cDCs. IL-21-induced IL-1β processing in cDCs does not require caspase-1 or caspase-8 but depends on IL-21-mediated death and activation of serine protease(s). Moreover, STAT3-dependent IL-1β expression in cDCs at least partially explains the IL-21-mediated pathologic response occurring during infection with pneumonia virus of mice. These results demonstrate lineage-restricted IL-21-induced IL-1β via a non-canonical pathway and provide evidence for its importance in vivo.

No MeSH data available.


Related in: MedlinePlus