11 beta -HSD1 inhibition reduces atherosclerosis in mice by altering proinflammatory gene expression in the vasculature

11 beta -Hydroxysteroid dehydrogenase type 1 (11 beta -HSD1) is implicated in the etiology of metabolic syndrome. We previously showed that pharmacological inhibition of 11 beta -HSD1 ameliorated multiple facets of metabolic syndrome and attenuated atherosclerosis in ApoE-/- mice. However, the molecular mechanism underlying the atheroprotective effect was not clear. In this study, we tested whether and how 11 beta -HSD1 inhibition affects vascular inflammation, a major culprit for atherosclerosis and its associated complications. ApoE-/- mice were treated with an 11 beta -HSD1 inhibitor for various periods of time. Plasma lipids and aortic cholesterol accumulation were quantified. Several microarray studies were carried out to examine the effect of 11 beta -HSD1 inhibition on gene expression in atherosclerotic tissues. Our data suggest 11 beta -HSD1 inhibition can directly modulate atherosclerotic plaques and attenuate atherosclerosis independently of lipid lowering effects. We identified immune response genes as the category of mRNA most significantly suppressed by 11 beta -HSD1 inhibition. This anti-inflammatory effect was further confirmed in plaque macrophages and smooth muscle cells procured by laser capture microdissection. These findings in the vascular wall were corroborated by reduction in circulating MCP1 levels after 11 beta -HSD1 inhibition. Taken together, our data suggest 11 beta -HSD1 inhibition regulates proinflammatory gene expression in atherosclerotic tissues of ApoE-/- mice, and this effect may contribute to the attenuation of atherosclerosis in these animals.