Abstract 17560: Close Interrelationship Between Macrophage Pro-inflammatory Activation and Metabolism in an Atherosclerotic Environment
Background: While prior work links macrophage (Mø) pro-inflammatory activation and metabolism, it remains unclear whether the high glycolytic flux (GlyFx) associated with Mø activation represents a simple binary survival mechanism or whether a more complex relationship exists.
Objectives: To investigate this relationship, we tested the hypothesis that impairment of either GlyFx or hypoxic sensing leads to decreased Mø pro-inflammatory (M1) activation. We also explored whether Mø GlyFx and pro-inflammatory activation are closely matched.
Methods: In vitro experiments were conducted in human and murine Mø. Proinflammatory activation was measured as TNF-α release and GlyFx as Fru-2,6-P2 production (the product of its rate-limiting step). Mø were incubated overnight with various combinations of atheromatous stimuli: LDL, oxLDL, colony stimulating factor (CSF) and hypoxia. Experiments were performed in the presence or absence of 3PO [[Unable to Display Character: –]] an inhibitor of uPFK2 (ubiquitous 6-phosphofructo-2-kinase: the isoform with high net activity) and FM19G11 [[Unable to Display Character: –]] an inhibitor of HIF (hypoxia inducible factor). Experiments were repeated using RNA silencing.
Results: Inhibition of either uPFK2 or HIF significantly decreased TNF-α production across oxygen tensions (Fig ). Similar reductions in TNF-α and Fru-2,6-P2 concentrations were observed after silencing uPFK2 and HIF. Moreover, across various combinations of pro-atherogenic stimuli, a significant correlation was maintained between TNF-α release (Mø activation) and Fru-2,6-P2 production (GlyFx), regardless of whether or not GlyFx was inhibited by 3PO.
Conclusion: We show that in normoxic and hypoxic atherosclerotic conditions, Mø activation and GlyFx are tightly and linearly related, resulting in calibration of GlyFx to keep pace with degree of activation via a mechanism dependent on uPFK2 and HIF-1α. Impairment of uPFK2 or HIF may provide opportunities to limit atherosclerotic inflammation across oxygen tensions.
- © 2013 by American Heart Association, Inc.