Fatty acids induce increased granulocyte macrophage-colony stimulating factor secretion through protein kinase C-activation in THP-1 macrophages.

• Insulin resistance and type 2 diabetes are associated with elevated circulating levels of nonesterified FA (NEFA) and lipoprotein remnants. The dyslipidemia is an important contributor to the excess arterial disease associated with insulin resistance and type 2 diabetes, but the mechanisms involved are elusive. In the present study we examined the effect of NEFA on macrophages. For this purpose, we utilized human macrophages, prepared by treating THP-1 monocytes with phorbol ester. We found that albumin-bound NEFA at physiological levels increase the secretion of granulocyte macrophage-colony stimulating factor (GM-CSF) by the THP-1 macrophages in a dose-dependent manner. The effect was registered as an increase in mRNA, and the amount of GM-CSF secreted correlated with the accumulation of TAG and DAG in the cell. The NEFA-induced rise in GM-CSF appeared to be mediated by activation of protein kinase C, probably acting on extracellular signal-regulated kinases 1 and 2 and being calcium dependent. We speculate that increased secretion of GM-CSF by resident macrophages in the intima exposed chronically to high levels of NEFA, such as those present in insulin resistance, may contribute to a proatherogenic response of arterial cells.

Nyckelord

Calcium Channel Blockers

pharmacology

Cell Line

Enzyme Activation

Fatty Acids

pharmacology

Flavonoids

pharmacology

Granulocyte-Macrophage Colony-Stimulating Factor

genetics

metabolism

Humans

Linoleic Acid

pharmacology

Macrophages

drug effects

enzymology

Mitogen-Activated Protein Kinase 3

metabolism

Nifedipine

pharmacology

Phosphorylation

drug effects

Protein Kinase C

metabolism

Protein Kinase Inhibitors

pharmacology

RNA

Messenger

analysis

Tetradecanoylphorbol Acetate

pharmacology

Up-Regulation

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