Alpha-chlorofatty acid accumulates in activated monocytes and causes apoptosis through reactive oxygen species production and endoplasmic reticulum stress.
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ABSTRACT: Myeloperoxidase-enriched monocytes play important roles in inflammatory disease, such as atherosclerosis. We previously demonstrated that ?-chlorofatty aldehydes are produced as a result of plasmalogen targeting by myeloperoxidase-derived hypochlorous acid in activated monocytes. Here, we show ?-chlorofatty acid (?-ClFA), a stable metabolite of ?-chlorofatty aldehydes, accumulates in activated monocytes and mediates the molecular effects of ?-ClFA on monocytes/macrophages.Liquid chromatography-mass spectrometry revealed that ?-ClFA is elevated 5-fold in phorbol myristate-stimulated human monocytes rising to ?20 ?mol/L when compared with unstimulated cells. Using human THP-1 monocytes and RAW 264.7 cells as in vitro models, we tested the hypothesis that ?-ClFA is a cell death mediator that could potentially participate in pathophysiological roles of monocytes in diseases, such as atherosclerosis. Indeed, 2-chlorohexadecanoic acid, the 16-carbon molecular species of ?-ClFA, caused significant apoptosis of primary monocytes. Similarly, 2-chlorohexadecanoic acid also caused apoptosis in THP-1 human monocytes and RAW 264.7 mouse macrophages as determined by annexin V-propidium iodide staining and terminal deoxynucleotidyl transferase dUTP nick end labeling staining, respectively. 2-Chlorohexadecanoic acid treatment also increased caspase-3 activity and poly (ADP-ribose) polymerase cleavage in THP-1 cells. 2-Chlorohexadecanoic acid likely elicits apoptosis by increasing both reactive oxygen species production and endoplasmic reticulum stress because antioxidants and CCAAT/enhancer-binding protein homologous protein block such induced cell apoptosis.The stable chlorinated lipid, ?-ClFA, accumulates in activated primary human monocytes and elicits monocyte apoptosis through increased reactive oxygen species production and endoplasmic reticulum stress, providing a new insight into chlorinated lipids and monocytes in inflammatory disease.
SUBMITTER: Wang WY
PROVIDER: S-EPMC3951512 | biostudies-literature | 2014 Mar
REPOSITORIES: biostudies-literature
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