Tissue inhibitor of metalloproteinase-1 mRNA production and protein secretion are induced by interleukin-1β in 3T3-L1 adipocytes

The adipokine tissue inhibitor of metalloproteinase (TIMP)-1 is upregulated when weight is gained and promotes adipose tissue development. In the present study, the effect of insulin resistance-inducing and proinflammatory interleukin (IL)-1β on TIMP-1 gene expression and secretion was investigated in 3T3-L1 adipocytes. Interestingly, protein secretion and mRNA production of TIMP-1 were significantly stimulated by IL-1β. Thus, IL-1β induced TIMP-1 secretion in a dose-dependent manner with maximal 3.5-fold upregulation seen at 0.67 ng/ml IL-1β relative to untreated cells. Furthermore, TIMP-1 mRNA synthesis was significantly stimulated by IL-1β in a dose-dependent fashion with 2.5-fold induction seen at IL-1β concentrations as low as 0.02 ng/ml and maximal 8.1-fold upregulation found at 20 ng/ml effector. Induction of TIMP-1 mRNA was also time dependent with maximal 9.6-fold upregulation detectable after 8 h of IL-1β treatment. Signaling studies suggested that janus kinase 2 is involved in IL-1β-induced TIMP-1 mRNA expression. Taken together, our results demonstrate that the TIMP-1 expression is selectively upregulated by proinflammatory IL-1β, supporting a direct association between insulin resistance, inflammation, and adipose tissue development in obesity.