Increased Expression of Glutathione Reductase in Macrophages Decreases Atherosclerotic Lesion Formation in Low-Density Lipoprotein Receptor–Deficient Mice

Abstract

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 cyto -EGFP) or mitochondrial GR (GR mito -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 cyto -EGFP or GR mito -EGFP-expressing bone marrow had lesion areas (PϽ0.009) that were 32% smaller than recipients of EGFP-expressing bone marrow. In cultured macrophages, adenovirus-mediated overexpression of GR cyto -EGFP or GR mito -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.

Redox regulation of MAPK phosphatase 1 controls monocyte migration and macrophage recruitment

“…Two weeks before irradiation and bone marrow transplantation, recipient LDLR −/− mice were put on acidified water containing sulfamethoxazole (160 ng/mL) and trimethoprim (32 ng/mL) and were maintained on antibiotics for 4 wk. Bone marrow cells were isolated by flushing the femurs and tibias with Iscove's Modified Dulbecco's Medium (Gibco) containing 2% (vol/vol) FBS as described previously (43). Bone marrow cells (2 × 10 6 cells in 0.2 mL) were injected via the lateral tail vein into lethally irradiated (two equal doses of 4.7 Gy, 3 h apart; Mark I-68 Irradiator; JL Shepherd) recipient mice (n = 5 per group).…”

Redox Control Systems in the Nucleus: Mechanisms and Functions

“…A role of GR in cardiovascular disease (CVD) also has been investigated (104,149,196) but specific nuclear functions have not been delineated. Decreased levels of GSH and GSHrelated antioxidant enzymes, GR, GST, GPx, have been observed in human atherosclerotic lesions.…”

“…Decreased levels of GSH and GSHrelated antioxidant enzymes, GR, GST, GPx, have been observed in human atherosclerotic lesions. Conversely, overexpression of GR targeted to cytoplasm or mitochondria in bone marrow-derived cells protected cells from oxidized LDL-induced mitochondrial hyperpolarization and reduced atherosclerotic lesion formation (149). Studies to define the role of GR in CVD have been extended to the regulation of signaling pathways.…”

ProteinS-Glutathionylation Mediates Macrophage Responses to Metabolic Cues from the Extracellular Environment

“…These data raise the question whether protein S-glutathionylation is limited to only select proteins and specific pathways or whether this unique post-translational modification may play a broader functional role in monocytes and macrophages. In support of the latter hypothesis, we found that metabolic stress increases global S-glutathionylation in peritoneal macrophages from mice fed a high-fat diet (HFD) (47). Increased S-glutathionylation correlated with functional changes in these macrophages, including the hypersensitization to chemokine-induced adhesion and accelerated monocyte chemotaxis, a phenomenon we termed metabolic priming of monocytes (47,62).…”

“…To overexpress human Grx1 in THP-1 monocytes, we used a doxycycline-inducible Tet-On adenoviral system expressing a Grx1-EGFP fusion protein (47,62). THP-1 monocytes were incubated for 24 h with adenoviruses (multiplicity of infection = 25) in complete growth media.…”