Tumor Necrosis Factor α and Interleukin 1β Enhance the Cortisone/Cortisol Shuttle

Endogenously released or exogenously administered glucocorticosteroids are relevant hormones for controlling inflammation. Only 11β-hydroxy glucocorticosteroids, but not 11-keto glucocorticosteroids, activate glucocorticoid receptors. Since we found that glomerular mesangial cells (GMC) express 11β-hydroxysteroid dehydrogenase 1 (11β-OHSD1), which interconverts 11-keto glucocorticosteroids into 11β-hydroxy glucocorticosteroids (cortisone/cortisol shuttle), we explored whether 11β-OHSD1 determines the antiinflammatory effect of glucocorticosteroids. GMC exposed to interleukin (IL)-1β or tumor necrosis factor α (TNF-α) release group II phospholipase A2 (PLA2), a key enzyme producing inflammatory mediators. 11β-hydroxy glucocorticosteroids inhibited cytokine-induced transcription and release of PLA2 through a glucocorticoid receptor–dependent mechanism. This inhibition was enhanced by inhibiting 11β-OHSD1. Interestingly, 11-keto glucocorticosteroids decreased cytokine-induced PLA2 release as well, a finding abrogated by inhibiting 11β-OHSD1. Stimulating GMC with IL-1β or TNF-α increased expression and reductase activity of 11β-OHSD1. Similarly, this IL-1β– and TNF-α–induced formation