Oxidized phospholipids in vivo

Oxidized phospholipids (OxPLs) are generated by enzymatic and non-enzymatic oxidation of esterified polyunsaturated fatty acids. Experiments in vitro and in vivo documented multiple activities of OxPLs potentially important for cardiovascular disease and inflammation, including initiation of leukocyte extravasation, thrombogenic shift and angiogenic response. OxPLs are present in normal tissues and their levels are increased in various pathologies reaching concentrations sufficient to induce biological effects. However, the (patho)physiological role of OxPLs in vivo is only starting to be elucidated because data on the functional activity of OxPLs until now were obtained using artificially oxidized lipids. In this project, the levels of endogenous OxPLs will be modulated in vivo by overexpression of enzymes that generate or inactivate OxPLs, such as phospholipid-specific forms of lipoxygenase and glutathione peroxidase. Tumor xenotransplants grown from cell lines stably transfected with these genes will be analyzed for expression of genes and proteins previously shown to be induced by OxPLs. In addition, tumor vessel density, leukocyte infiltration and clotting activity of tumor tissue will be analyzed. Furthermore, quantification of OxPLs in tumors will be performed using mass-spectrometry and immune detection. The project is expected to provide proof-of-principle for biological importance of endogenously produced OxPLs and thus to boost further studies into biochemistry of these lipids and their application as diagnostic and therapeutic targets.

Different (patho)physiological conditions lead to accumulation of oxidized phospholipids (OxPLs). These phospholipids have been previously shown to cause a variety of biological effects. The knowledge about concentrations of oxidized phospholipids in biological samples is therefore very important in order to understand to what extent oxidized phospholipids influence normal biological processes. Two new simplified methods for detection of oxidized phospholipids in biological samples have been developed within the project. One method allows detection of oxidized phospholipids by mass-spectrometry. Another method has been developed to analyze human blood samples using novel antibodies in order to diagnose hypercholesterolemia, which is linked to atherosclerosis and coronary artery disease. Additionally, novel phospholipid derivatives with anti-inflammatory properties have been synthesized and tested. These compounds will serve as leads for further development of novel anti-inflammatory drugs.