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Lipolysis products alter protein and lipid structural characteristics in the plasma membranes of human monocytes
Author(s) -
Higgins Laura Jane,
Saad Nabil M,
Fiehn Oliver,
Rutledge John C
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a59-a
Subject(s) - lipolysis , chemistry , chylomicron , monocyte , lipoprotein , lipid droplet , biochemistry , biology , very low density lipoprotein , cholesterol , immunology , adipose tissue
The interactions between lipids and monocytes are fundamental to the development of atherosclerosis. Postprandial lipemia is characterized by increased circulating triglyceride‐rich lipoproteins (TGRLs). Prolonged exposure of these lipids and their lipolysis products to cellular membranes is thought to promote atherosclerosis. We hypothesize that TGRL lipolysis products activate monocytes, generating novel cellular phenotypes that predict atherosclerosis. We investigated this hypothesis by treating primary human monocytes with either TGRL lipolysis products (150 mg/dL TG + 3 U lipoprotein lipase) or media for 3.5 hours. Fourier transform infrared radiation (FTIR) spectra of the amide signature region were obtained from treated and untreated cells, and their metabolic signatures determined by direct nano‐electrospray ionization FT‐MS. FTIR spectra of TGRL‐treated cells revealed a spectral signature characterized by proteins with increased β‐sheet conformations, possibly due to changes in inflammatory marker expression. FT‐MS analysis showed an increase in phosphatidylcholine and desaturases in TGRL‐treated cells, indicating changes in membrane fluidity. These results demonstrate that lipid lipolysis products exert drastic changes on monocyte surfaces and may contribute to the development of monocyte signatures that could predict atherosclerosis. This research was partially supported by a fellowship under the Training Program in Biomolecular Technology (T32‐GM08799) at the University of California, Davis.