11β-HSD1 Modulates LPS-Induced Innate Immune Responses in Adipocytes by Altering Expression of PTEN

Inhibition of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) represents a therapeutic target for treating hyperglycemia in type 2 diabetes. Here, we investigate the effects of 11β-HSD1 on the innate immune response of adipocytes to produce proinflammatory cytokines. The 11β-HSD1 inhibitor emodin, or 11β-HSD1-targeted small interfering RNA, dose dependently suppressed IL-6, IL-1β, and TNF-α expression in lipopolysaccharide-treated 3T3-L1 adipocytes. Inhibiting 11β-HSD1 also reduced phosphatase and tensin homologue (PTEN) expression, a negative regulator of phosphatidylinositol 3-kinase effects, whereas 1pM cortisone or dexamethasone induced IL-6 and PTEN levels. PTEN-targeted small interfering RNA decreased IL-6, IL-1β, and TNF-α without affecting 11β-HSD1 levels. Correspondingly, emodin increased phosphorylated protein kinase B (p-PKB) (Ser473) to PKB ratio but not p-PKB (Thr308) to PKB ratio. Emodin did not increase the p-PKB (Ser473) to PKB ratio when the rapamycin-insensitive companion of mTOR was ...