Abstract 450: Monocytic Glutaredoxin 1 Protects Mice Against Obesity, Hyperglycemia and Atherosclerosis

Abstract

Overexpression of glutaredoxin 1 (Grx1) protects monocytes from metabolic stress-induced priming, i.e. dysregulation and hypersensitization to chemokines (Ullevig et al. ATVB 2012). To address the role of monocytic Grx1 in mice and in the development of atherogenesis and obesity, we transplanted bone marrow (BM) from either wild-type (WT) or Grx1 -/- donor mice into atherosclerosis-prone LDLR -/- mice and fed these mice a high-fat diet (HFD) for up to 20 weeks. Grx1 Leuko -/- mice showed accelerated weight gain after 9 weeks followed by early onset of hyperglycemia. After 6 weeks on HFD, atherosclerotic lesions were slightly larger in Grx1 Leuko -/- mice than in WT mice, but the differences did not reach statistical significance. However, after 20 weeks, Grx1 Leuko -/- mice showed 36% larger lesions than WT-BM recipients, and monocyte chemotaxis in vivo was increased 1.6-fold. Furthermore, compared to WT-BM recipients, adipose tissues and livers of Grx1 Leuko -/- mice also showed increased macrophage content and elevated tissue inflammation as determined by IHC and qRT-PCR-based gene array. Adipose tissue in particular, showed significant increases in the expression of proinflammatory genes in addition to an increased abundance of proinflammatory “crown-like” structures. In contrast, genes associated with inflammation resolving macrophages were significantly suppressed. Macrophages isolated from Grx1 -/- mice and stimulated with INFγ+TNFα also showed increased expression of pro-inflammatory M1-associated genes, whereas M2-associated genes were suppressed in Grx-1 -/- macrophages activated with IL-4. Furthermore, macrophages from Grx1 -/- mice exposed to metabolic stress also display increased protein S -glutathionylation, enhanced hypersensitization to chemokine, and impaired autophagy compared to macrophages from wild-type mice. Taken together, our data show that loss of monocytic Grx1 worsens monocyte priming in response to HFD-induced metabolic stress and accelerates the infiltration of dysfunctional monocyte-derived macrophages into tissues, such as aorta, liver and adipose tissues. We conclude that monocytic Grx1 is critical for maintaining metabolic homeostasis in mice and protects mice against obesity and atherogenesis.