Induction of M2 regulatory macrophages through the β2-adrenergic receptor with protection during endotoxemia and acute lung injury - PubMed (original) (raw)
Induction of M2 regulatory macrophages through the β2-adrenergic receptor with protection during endotoxemia and acute lung injury
Jamison J Grailer et al. J Innate Immun. 2014.
Abstract
The main drivers of acute inflammation are macrophages, which are known to have receptors for catecholamines. Based on their function, macrophages are broadly categorized as having either M1 (proinflammatory) or M2 phenotypes (anti-inflammatory). In this study, we investigated catecholamine-induced alterations in the phenotype of activated macrophages. In the presence of lipopolysaccharide (LPS), mouse peritoneal macrophages acquired an M1 phenotype. However, the copresence of LPS and either epinephrine or norepinephrine resulted in a strong M2 phenotype including high levels of arginase-1 and interleukin-10, and a reduced expression of M1 markers. Furthermore, epinephrine enhanced macrophage phagocytosis and promoted type 2 T-cell responses in vitro, which are known features of M2 macrophages. Analysis of M2 subtype-specific markers indicated that LPS and catecholamine-cotreated macrophages were not alternatively activated but were rather of the regulatory macrophage subtype. Interestingly, catecholamines signaled through the β2-adrenergic receptor but not the canonical cAMP/protein kinase A signaling pathway. Instead, the M2 pathway required an intact phosphoinositol 3-kinase pathway. Blockade of the β2-adrenergic receptor reduced survival and enhanced injury in mouse models of endotoxemia and LPS-induced acute lung injury, respectively. These results demonstrate a role for the β2-adrenergic receptor in promoting the M2 macrophage phenotype.
Figures
Fig. 1
Catecholamines promoted the M2 macrophage activation phenotype. a-d Mouse peritoneal macrophages were incubated with LPS (100 ng/ml) in the absence or copresence of epinephrine (1 μ
M
) or norepinephrine (1 μ
M
) for 18 h. a Relative expression of mRNA transcripts for iNOS and arginase-1. b Culture supernatant levels of IL-12p40 and IL-10 determined by ELISA after 18 h. c Confocal microscopic analysis of macrophage phagocytosis of fluorescent E. coli bioparticles. d Flow cytometric analysis of the phagocytosis of fluorescent E. coli bioparticles. e Levels of IFN-γ or IL-4 in DO11.10 transgenic lymphocyte/macrophage culture supernatants. Macrophages were incubated in the presence or absence of LPS (100 ng/ml) and/or epinephrine (1 μ
M
) for 1 h. Cells were washed, and 150 μg/ml ovalbumin was added for 30 min. Then, peripheral lymph node lymphocytes were added, and cell-free culture supernatants were harvested after 84 h. Levels of cytokines were determined by ELISA. MFI = Mean fluorescence intensity; Neg. Ctrl. = negative control.
Fig. 2
Catecholamines induced the regulatory macrophage M2 phenotype. a Macrophages were treated with LPS (100 ng/ml) in the presence or absence of epinephrine (1 μ
M
) for 18 h. The levels of FIZZ and YM1 (mRNA, RT-PCR) and CD206 (surface mean fluorescence intensity, flow cytometry) were determined. b Dose-response curve of epinephrine (left) or norepinephrine (right) in the presence of LPS (100 ng/ml). The levels of IL-10 in culture supernatants after 4 h were determined by ELISA. c Macrophages were treated with LPS (100 ng/ml) in the absence or copresence of epinephrine (1 μ
M
). IL-10 mRNA (left) and protein in culture supernatants (right) were determined at different time points following stimulation. Neg. Ctrl. = Negative control.
Fig. 3
Epinephrine signals through the β2-adrenergic receptor. a Macrophages were incubated in the presence or absence of LPS (100 ng/ml), epinephrine (1 μ
M
), and/or adrenergic receptor antagonists (1 μ
M
each). The levels of IL-10 in culture supernatants were determined after 4 h. b Macrophages were incubated in the presence or absence of LPS (100 ng/ml), epinephrine (1 μ
M
), and/or β2-adrenergic receptor antagonist ICI 118,551 for 18 h. The relative expression of mRNA transcripts for iNOS and arginase-1 was determined by RT-PCR. Neg. Ctrl. = Negative control.
Fig. 4
Catecholamine-enhanced IL-10 production is mediated through the PI3K pathway. Macrophages were incubated with LPS (100 ng/ml) in the absence or copresence of epinephrine (1 μ
M
). IL-10 levels in the culture supernatants after 4 h were determined by ELISA. Cells were pretreated with inhibitors for 30 min prior to stimulation. a Adenylate cyclase activity was inhibited with 2′5′-DDA (20 μ
M
) or SQ22536 (10 μ
M
). b PKA activity was inhibited with PKA inhibitor 14-22 amide (5 μ
M
). c PI3K activity was inhibited with various doses of wortmannin.
Fig. 5
Activation of the β2-adrenergic receptor by endogenous catecholamines is protective during acute inflammation. a Survival curve following administration of LPS with or without ICI 118,551 (500 μg/mouse, n ≥ 11 mice per group). b Plasma levels of IL-10 during endotoxemia as described in a (n = 4 mice per group). c Macrophages were incubated in vitro in the presence or absence of LPS (100 ng/ml) and epinephrine (1 μ
M
) for 1 h. Cells were harvested, washed, and adoptively transferred to mice (1 × 106 cells/mouse i.p.). Four hours after cell transfer, endotoxemia was performed (time 0, n ≥ 8 mice per group). d-g ALI was induced via i.t. administration of LPS (60 μg) and BALF was harvested 8 h later. Sham animals received only sterile saline. The β2-adrenergic receptor was blocked by administration of ICI 118,551 (25 mg/kg i.p. and 6 ng i.t.). BALF levels of albumin (d), neutrophil numbers (e), and IL-10 (f) and TNF (g) levels were determined (n ≥ 9 mice per group). n.s. = Not significant.
Fig. 6
Summary of the effects of catecholamines on the promotion of anti-inflammatory (M2) macrophage functions resulting in reduced inflammation.
References
- Lawrence T, Natoli G. Transcriptional regulation of macrophage polarization: enabling diversity with identity. Nat Rev Immunol. 2011;11:750–761. - PubMed
- Gordon S. Alternative activation of macrophages. Nat Rev Immunol. 2003;3:23–35. - PubMed
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