BACKGROUNDGlucolipotoxicity might play an important role in the β cell decompensation stage during the development of obesity-associated type 2 diabetes. Tissue inhibitor of metalloproteinase-1 (TIMP-1) inhibits matrix metalloproteinase (MMP) activity and regulates proliferation and apoptosis of a variety of cell types, including pancreatic β-cells. In the present study, we investigated whether TIMP-1 counteracts glucolipotoxicity in the pancreatic β-cell line INS-1.

METHODSINS-1 cells were incubated in normal or high glucose, with or without palmitate (0.4 mmol/L), in the presence of TIMP-1 or MMP inhibitor GM60001. In some experiments, cells were pretreated with phosphatidylinositol-3 (PI-3) kinase inhibitor, LY294002 or wortmannin. The amount of dead INS-1 cells was determined by HO342 and propidium iodide staining. Akt phosphorylation was evaluated by Western blotting analysis to investigate a possible mechanism of TIMP-1's action.

RESULTSTIMP-1 protected INS-1 cells from glucolipotoxicity independent of MMP inhibition. TIMP-1 stimulated Akt phosphorylation. Inhibition of the PI-3 kinase pathway abolished the survival effect of TIMP-1.

CONCLUSIONTIMP-1 may counteract glucolipotoxicity induced β-cell death via a PI-3 kinase pathway.