Increased expression of glutathione reductase in macrophages decreases atherosclerotic lesion formation in low-density lipoprotein receptor-deficient mice

OBJECTIVE - Thiol oxidative stress leads to macrophage dysfunction and cell injury, and has been implicated in the development of atherosclerotic lesions. We investigated if strengthening the glutathione-dependent antioxidant system in macrophages by overexpressing glutathione reductase (GR) decreases the severity of atherosclerosis. METHODS AND RESULTS - Bone marrow cells infected with retroviral vectors expressing either enhanced green fluorescent protein (EGFP) or an EGFP-fusion protein of cytosolic GR (GR-EGFP) or mitochondrial GR (GR-EGFP) were transplanted into low-density lipoprotein receptor-deficient mice. Five weeks after bone marrow transplantation, animals were challenged with a Western diet for 10 weeks. No differences in either plasma cholesterol and triglyceride levels or peritoneal macrophage content were observed. However, mice reconstituted with either GR-EGFP or GR-EGFP-expressing bone marrow had lesion areas (P<0.009) that were 32% smaller than recipients of EGFP-expressing bone marrow. In cultured macrophages, adenovirus-mediated overexpression of GR-EGFP or GR-EGFP protected cells from mitochondrial hyperpolarization induced by oxidized low-density lipoprotein. CONCLUSION - This study provides direct evidence that the glutathione-dependent antioxidant system in macrophages plays a critical role in atherogenesis, and suggests that thiol oxidative stress-induced mitochondrial dysfunction contributes to macrophage injury in atherosclerotic lesions.