Characterization of lipid efflux particles generated by seminal phospholipid-binding proteins |
| |
Authors: | Robert Moreau Puttaswamy Manjunath |
| |
Institution: | Department of Medicine, University of Montreal and Guy Bernier Research Centre, Maisonneuve-Rosemont Hospital, 5415 boul. L’Assomption, Montreal, Que. H1T 2M4, Canada |
| |
Abstract: | We reported recently that the choline phospholipid-binding proteins (BSP-A1/-A2, BSP-A3 and BSP-30-kDa) of bovine seminal plasma (BSP) stimulate cholesterol and choline phospholipid efflux from fibroblasts. In this study, we characterized the lipid efflux particles generated by BSP proteins. The density gradient ultracentrifugation of the efflux medium from radiolabeled fibroblasts incubated with BSP proteins showed a single peak of 3H]cholesterol between density (d) 1.12 and 1.14 g/ml, which is in the range of high-density lipoproteins. Size-exclusion chromatographic and immunoblot analysis revealed that the efflux particles have a large size equal to or bigger than very low-density lipoproteins and contained BSP proteins. Lipid analysis of density gradient and gel filtration fractions from efflux medium of simultaneously labeled fibroblasts (3H]cholesterol and 3H]choline) incubated with BSP proteins showed that the efflux particles were homogeneous and composed of cholesterol and choline phospholipids. The lipid particles contained BSP proteins, cholesterol and choline phospholipids in molar ratio of 0.05:1.21:1, respectively. Agarose gel electrophoresis showed that the BSP-generated lipid particles had a γ migration pattern which is slower than low-density lipoproteins. The sonication of cholesterol and BSP proteins followed by gel filtration chromatographic analysis indicated no direct binding of cholesterol to BSP proteins. These results taken together indicate that BSP proteins induce a concomitant cholesterol and choline phospholipid efflux and generate large protein–lipid particles. |
| |
Keywords: | Cholesterol efflux Phospholipid efflux Seminal phospholipid-binding protein Fibroblast DMEM Dulbecco’s modified Eagle’s medium FBS fetal bovine serum BSP bovine seminal plasma apoA apolipoprotein A HDL high-density lipoprotein LDL low-density lipoprotein VLDL very low-density lipoprotein FC free cholesterol PC phosphatidylcholine RCT reverse cholesterol transport Corresponding author Fax: +1-514-252-3569 |
本文献已被 ScienceDirect 等数据库收录! |