Human monocyte-derived macrophages (MDMs) were placed in 5 mmol/L (NG) or 25 mmol/L (HG) glucose for 24 hours. MacCM was collected and its effect on differentiation of human subcutaneous abdominal preadipocytes and adipocyte inflammation was evaluated.
HG-MacCM, but not NG-MacCM, inhibited triacylglycerol (TG) accumulation and protein expression of peroxisome proliferator-activated receptor γ (PPARgamma) during human adipogenesis. Preadipocytes differentiated in HG-MacCM displayed a more pro-inflammatory phenotype, as assessed by increased interleukin-6 and monocyte chemotactic protein-1 (MCP-1), as well as reduced adiponectin mRNA expression. In MDMs, HG increased phosphorylation of inhibitor of kappaB kinase (IKK)-beta and decreased protein expression of inhibitor of kappaB alpha. HG also reduced protein expression of PPARgamma in MDMs. However, no MDM changes in mRNA expression of MCP-1, interleukin-1beta or tumor necrosis factor-alpha were detected. The stimulatory effect of HG-MacCM on MCP-1 expression in adipocytes was partially inhibited when MDMs were treated with sc-514 (IKKbeta inhibitor).
High glucose concentration accentuates the anti-adipogenic and pro-inflammatory effects of MacCM on human preadipocytes.