Dual Beneficial Effects of Methylnissolin-3-O-β-d-Glucopyranoside on Obesity-Induced Inflammatory Responses in Adipocyte-Macrophage Co-Culture

Abstract

Methylnissolin-3-O-β-d-glucopyranoside (MNG) is a pterocarpan analog, which protects EA.hy926 cells against oxidative damage through the Nrf2/HO-1 pathway. However, the effects of MNG on obesity-induced inflammatory responses in adipocyte-macrophage co-culture remain unclear. A differentiated murine preadipocyte cell line (3T3-L1) was co-cultured with a murine macrophage cell line (RAW264.7). Intracellular lipid accumulation was determined using Oil Red O staining. Western blotting was performed to investigate the expression of adipogenesis- and inflammation-associated proteins. Cell culture supernatants were assayed using ELISA kits to measure the levels of proinflammatory cytokines such as interleukin 6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1). MNG inhibited lipid accumulation and the production of IL-6 and MCP-1 in the 3T3-L1 and RAW264.7 cell co-culture. Moreover, MNG inhibited the protein expression of CCAAT/enhancer-binding protein alpha (C/EBPα), C/EBPβ, peroxisome proliferator-activated receptor γ (PPARγ), cyclooxygenase 2 (COX-2), and inducible nitric oxide synthase (iNOS) under the same co-culture conditions. MNG also inhibited IL-6 and MCP-1 production compared with the co-culture control. These findings demonstrate that MNG inhibited lipid accumulation and inflammatory response by downregulating IL-6 and MCP-1 production and protein expression of C/EBPβ, C/EBPα, PPARγ, COX-2, and iNOS in co-culture conditions with 3T3-L1 and RAW264.7 cells. These results suggest that MNG may be beneficial in preventing obesity-related inflammatory status.