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Autocrine IL-10 functions as a rheostat for M1 macrophage glycolytic commitment by tuning nitric oxide production ☆ ☆ ☆

View Article: PubMed Central - PubMed

ABSTRACT

Inflammatory maturation of M1 macrophages by proinflammatory stimuli such as toll like receptor ligands results in profound metabolic reprogramming resulting in commitment to aerobic glycolysis as evidenced by repression of mitochondrial oxidative phosphorylation (OXPHOS) and enhanced glucose utilization. In contrast, “alternatively activated” macrophages adopt a metabolic program dominated by fatty acid-fueled OXPHOS. Despite the known importance of these developmental stages on the qualitative aspects of an inflammatory response, relatively little is know regarding the regulation of these metabolic adjustments. Here we provide evidence that the immunosuppressive cytokine IL-10 defines a metabolic regulatory loop. Our data show for the first time that lipopolysaccharide (LPS)-induced glycolytic flux controls IL-10-production via regulation of mammalian target of rapamycin (mTOR) and that autocrine IL-10 in turn regulates macrophage nitric oxide (NO) production. Genetic and pharmacological manipulation of IL-10 and nitric oxide (NO) establish that metabolically regulated autocrine IL-10 controls glycolytic commitment by limiting NO-mediated suppression of OXPHOS. Together these data support a model where autocine IL-10 production is controlled by glycolytic flux in turn regulating glycolytic commitment by preserving OXPHOS via suppression of NO. We propose that this IL-10-driven metabolic rheostat maintains metabolic equilibrium during M1 macrophage differentiation and that perturbation of this regulatory loop, either directly by exogenous cellular sources of IL-10 or indirectly via limitations in glucose availability, skews the cellular metabolic program altering the balance between inflammatory and immunosuppressive phenotypes.

No MeSH data available.


Acute LPS stimulation of human and mouse macrophages leads to an immediate glycolytic burst that is dependent on glucose. Real time OCR and ECAR percent changes in mouse BMDM ±5 mM 2-DG and 100 ng/mL LPS or a combination of both (a). Human MDM real time OCR and ECAR stimulated ±10 mM 2-DG, 100 ng/mL of LPS or a combination of both (b). Data represent percent of resting control levels and are from one experiment representative of 2 (b) or 3 (a) independent experiments (mean±standard error of the mean (SEM) of the final three time points, n=5 per group). Values for bar graphs are derived from the three data points following addition of the experimental agent as noted on the line graphs. *p <0.05. Statistical significance was assessed by ANOVA with a Bonferroni post-test.
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f0005: Acute LPS stimulation of human and mouse macrophages leads to an immediate glycolytic burst that is dependent on glucose. Real time OCR and ECAR percent changes in mouse BMDM ±5 mM 2-DG and 100 ng/mL LPS or a combination of both (a). Human MDM real time OCR and ECAR stimulated ±10 mM 2-DG, 100 ng/mL of LPS or a combination of both (b). Data represent percent of resting control levels and are from one experiment representative of 2 (b) or 3 (a) independent experiments (mean±standard error of the mean (SEM) of the final three time points, n=5 per group). Values for bar graphs are derived from the three data points following addition of the experimental agent as noted on the line graphs. *p <0.05. Statistical significance was assessed by ANOVA with a Bonferroni post-test.

Mentions: Having established the basal metabolic status of macrophages we next analyzed metabolic responses of BMDM to LPS. LPS stimulation resulted in a progressive increase in ECARs within minutes (Fig. 1A). OCRs were unaffected over this timeframe (Fig. 1A). As shown in Fig. 1, addition of 2-DG during bioenergetic monitoring leads to an instant repression of basal ECARs. Further, 2-DG severely blunts LPS-stimulated increases in ECAR indicating glucose is absolutely necessary for the acute glycolytic elevation in BMDM. Identical results were found using human monocyte-derived macrophages (MDM) stimulated with LPS in the presence or absence of 2-DG (Fig. 1B). Together these data confirm that 2-DG inhibits the immediate LPS-induced increase in glycolytic flux.


Autocrine IL-10 functions as a rheostat for M1 macrophage glycolytic commitment by tuning nitric oxide production ☆ ☆ ☆
Acute LPS stimulation of human and mouse macrophages leads to an immediate glycolytic burst that is dependent on glucose. Real time OCR and ECAR percent changes in mouse BMDM ±5 mM 2-DG and 100 ng/mL LPS or a combination of both (a). Human MDM real time OCR and ECAR stimulated ±10 mM 2-DG, 100 ng/mL of LPS or a combination of both (b). Data represent percent of resting control levels and are from one experiment representative of 2 (b) or 3 (a) independent experiments (mean±standard error of the mean (SEM) of the final three time points, n=5 per group). Values for bar graphs are derived from the three data points following addition of the experimental agent as noted on the line graphs. *p <0.05. Statistical significance was assessed by ANOVA with a Bonferroni post-test.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037266&req=5

f0005: Acute LPS stimulation of human and mouse macrophages leads to an immediate glycolytic burst that is dependent on glucose. Real time OCR and ECAR percent changes in mouse BMDM ±5 mM 2-DG and 100 ng/mL LPS or a combination of both (a). Human MDM real time OCR and ECAR stimulated ±10 mM 2-DG, 100 ng/mL of LPS or a combination of both (b). Data represent percent of resting control levels and are from one experiment representative of 2 (b) or 3 (a) independent experiments (mean±standard error of the mean (SEM) of the final three time points, n=5 per group). Values for bar graphs are derived from the three data points following addition of the experimental agent as noted on the line graphs. *p <0.05. Statistical significance was assessed by ANOVA with a Bonferroni post-test.
Mentions: Having established the basal metabolic status of macrophages we next analyzed metabolic responses of BMDM to LPS. LPS stimulation resulted in a progressive increase in ECARs within minutes (Fig. 1A). OCRs were unaffected over this timeframe (Fig. 1A). As shown in Fig. 1, addition of 2-DG during bioenergetic monitoring leads to an instant repression of basal ECARs. Further, 2-DG severely blunts LPS-stimulated increases in ECAR indicating glucose is absolutely necessary for the acute glycolytic elevation in BMDM. Identical results were found using human monocyte-derived macrophages (MDM) stimulated with LPS in the presence or absence of 2-DG (Fig. 1B). Together these data confirm that 2-DG inhibits the immediate LPS-induced increase in glycolytic flux.

View Article: PubMed Central - PubMed

ABSTRACT

Inflammatory maturation of M1 macrophages by proinflammatory stimuli such as toll like receptor ligands results in profound metabolic reprogramming resulting in commitment to aerobic glycolysis as evidenced by repression of mitochondrial oxidative phosphorylation (OXPHOS) and enhanced glucose utilization. In contrast, &ldquo;alternatively activated&rdquo; macrophages adopt a metabolic program dominated by fatty acid-fueled OXPHOS. Despite the known importance of these developmental stages on the qualitative aspects of an inflammatory response, relatively little is know regarding the regulation of these metabolic adjustments. Here we provide evidence that the immunosuppressive cytokine IL-10 defines a metabolic regulatory loop. Our data show for the first time that lipopolysaccharide (LPS)-induced glycolytic flux controls IL-10-production via regulation of mammalian target of rapamycin (mTOR) and that autocrine IL-10 in turn regulates macrophage nitric oxide (NO) production. Genetic and pharmacological manipulation of IL-10 and nitric oxide (NO) establish that metabolically regulated autocrine IL-10 controls glycolytic commitment by limiting NO-mediated suppression of OXPHOS. Together these data support a model where autocine IL-10 production is controlled by glycolytic flux in turn regulating glycolytic commitment by preserving OXPHOS via suppression of NO. We propose that this IL-10-driven metabolic rheostat maintains metabolic equilibrium during M1 macrophage differentiation and that perturbation of this regulatory loop, either directly by exogenous cellular sources of IL-10 or indirectly via limitations in glucose availability, skews the cellular metabolic program altering the balance between inflammatory and immunosuppressive phenotypes.

No MeSH data available.