Inhibiting Glycolysis and ATP Production Attenuates IL-33-Mediated Mast Cell Function and Peritonitis

Abstract

Cellular metabolism and energy sensing pathways are closely linked to inflammation, but there is little understanding of how these pathways affect mast cell function. Mast cells are major effectors of allergy and asthma, and can be activated by the alarmin IL-33, which is linked to allergic disease. Therefore, we investigated the metabolic requirements for IL-33-induced mast cell function, to identify targets for controlling inflammation. We found that IL-33 increases glycolysis, glycolytic protein expression, and oxidative phosphorylation (OX PHOS). Inhibiting OX PHOS had little effect on cytokine production, but antagonizing glycolysis with 2-deoxyglucose or oxamate suppressed inflammatory cytokine production in vitro and in vivo. ATP reversed this suppression. Glycolytic blockade suppressed IL-33 signaling, including ERK phosphorylation, NFκB transcription, and ROS production in vitro, and suppressed IL-33-induced neutrophil recruitment in vivo. To test a clinically relevant way to modulate these pathways, we examined the effects of the FDA-approved drug metformin on IL-33 activation. Metformin activates AMPK, which suppresses glycolysis in immune cells. We found that metformin suppressed cytokine production in vitro and in vivo, effects that were reversed by ATP, mimicking the actions of the glycolytic inhibitors we tested. These data suggest that glycolytic ATP production is important for IL-33-induced mast cell activation, and that targeting this pathway may be useful in allergic disease.

The metabolic response to inflammation in astrocytes is regulated by nuclear factor‐kappa B signaling

“…Alternatively, the reduced glycolytic rate may prevent the production of carbon intermediates required for cytokine production, through limiting the repurposing of TCA cycle enzymes (Menk et al, 2018;Williams, O'Neill, & O'Neill, 2018). This would result in a negative feedback loop reducing the inflammatory response (Caslin et al, 2018;McGettrick & O'Neill, 2013). It has been reported that in macrophages 2-DG reduces mitochondrial function independently of glycolytic function (Wang et al, 2018); however, in our data there was no change in oxidative rate as a result of 2-DG treatment.…”

IL-33 drives the production of mouse regulatory T cells with enhanced in vivo suppressive activity in skin transplantation

“…These molecules augment the ability of IL‐33 Tregs to inhibit Teff responses through the production of adenosine from ATP. Extracellular ATP can act as a danger signal in response to cell damage, 63 with reports suggesting that IL‐33 and ATP may act to induce the release of one another under inflammatory conditions 64,65 . Thus coupled with reports that there is substantial release of IL‐33, ATP, and other alarmin/DAMPS after transplantation, IL‐33 Tregs may have a unique potential in modulating inflammation within an allograft microenvironment 66‐68 .…”

Lactic Acid Inhibits Lipopolysaccharide-Induced Mast Cell Function by Limiting Glycolysis and ATP Availability

“…7A, 7B). In a previous manuscript, we showed that micromolar quantities of labeled ATP diffuse into BMMC within 20 min (51), which can increase the ATP available in the cell for energy and bypass the need for ATP produced by glycolysis. These data, together with the experiments above, suggest that lactic acid suppresses LPS-induced glycolytic ATP production, effectively attenuating energy available for cell signaling and cytokine production (Fig.…”