Effect of (-)-epigallocatechin-3-gallate on anti-inflammatory response via heme oxygenase-1 induction during adipocyte-macrophage interactions.

In this study, we examined the effects of (-)-epigallocatechin-3-gallate (EGCG) on anti-inflammatory responses through the induction of heme oxygenase-1 (HO-1) in cocultured macrophages and adipocytes. EGCG significantly decreased the secretion of nitric oxide (NO) and monocyte chemoattractant protein-1 in the coculture of RAW 264.7 macrophages and differentiated 3T3-L1 adipocytes. In addition, EGCG inhibited the expression of inducible nitric oxide synthase in cocultured macrophages and peroxisome proliferator-activated receptor-gamma in cocultured adipocytes. Furthermore, the HO-1 expression showed an approximately 4-fold increase in cocultured adipocytes and an approximately 6-fold increase in cocultured macrophages. Lastly, HO-1 silencing induced NO generation in cocultured cells regardless of EGCG treatment. These results indicate that EGCG inhibited inflammatory responses by suppressing the production of proinflammatory cytokines through HO-1 induction during adipocyte-macrophage interaction.