Abstract 175: Lack of Macrophage GLUT1-Mediated Glucose Metabolism Increases Atherosclerotic Lesion Instability

Abstract

Macrophages play a key role in the pathogenesis of atherosclerosis. Metabolic programs powered by glucose or lipid enable macrophages to elicit pro- or anti-inflammatory responses, respectively. Although the chronic inflammatory feature of atherosclerosis has been well-established, the role of macrophage substrate metabolism in atherogenesis remains unclear. We previously demonstrated that macrophages with elevated GLUT1-mediated glucose metabolism have an increased inflammatory response. Therefore, we created a novel macrophage GLUT1-deficient murine model by crossing GLUT1 floxed to LysM-Cre mice. Recent work suggests that lack of GLUT1 reduces the pro-inflammatory response and the ability for GLUT1-/- macrophages to polarize to the classically activated state in vitro. Therefore, the objective of this study was to examine how macrophage metabolic reprogramming affects the development of atherosclerosis. We hypothesized that macrophages with restricted glucose metabolism due to lack of glucose transporter GLUT1 will have reduced pro-inflammatory activation during atherogenesis. We transplanted bone marrow from Glut1MΦfl/fl or Glut1MΦ-/- mice into Ldlr-/- mice and fed mice a Western diet for 12 weeks. Glut1MΦfl/fl Ldlr-/- or Glut1MΦ-/- Ldlr-/- chimeric mice did not exhibit significant differences in body weight, body composition, blood pressure, fasting blood glucose, or triacylglycerol and LDL and HDL cholesterol. Digital histology analysis of Oil Red O stained slides indicated that deleting macrophage GLUT1 did not affect total lesion area in aortic root; however, mice with blunted glucose metabolism displayed more and larger necrotic cores. Ongoing studies are investigating apoptosis and phagocytic capacity of macrophages with and without GLUT1 to elucidate the roles of macrophage glucose metabolism on the morphology of atherosclerotic lesion. In summary, we observed that mice lacking macrophage GLUT1 developed increased necrotic cores in lesions of the aorta root relative to mice with wild type macrophage GLUT1 which suggests that maintenance of atherosclerotic lesion stability may be regulated by glucose-dependent mechanisms.