Abstract 14993: Proteomic Analysis of Chylomicron Remnants Isolated by Apolipoprotein B-48 Immunoprecipitation
Introduction: Postprandial hypertriglyceridemia is caused by overproduction or impaired clearance of apolipoprotein (apo)B-48-containing lipoproteins, chylomicrons (CMs) and CM remnants (CM-Rs). In vitro studies have suggested that CM-Rs may lead to the formation of atherosclerotic plaques. By our ELISA and CLEIA for measuring human serum apoB-48 concentrations, we reported fasting apoB-48 concentrations are significantly higher in patients with dyslipidemia, diabetes mellitus, metabolic syndrome and chronic kidney disease than in normal subjects, and correlated with the IMT of carotid arteries and the prevalence of coronary heart disease. However, it has been technically very difficult to isolate CM-Rs and to evaluate the atherogenicity of pure CM-Rs.
Hypothesis: We tried to selectively isolate CM-Rs and analyze their lipoprotein and proteomics profiles and assessed their atherogenicity.
Methods: Fractions containing CM-Rs and VLDL (d<1.01 mg/dL) were isolated from the postprandial sera of healthy volunteers by two-step ultracentrifugation. CM-Rs were selectively eluted and isolated by immunoprecipitation using anti-human apoB-48 monoclonal antibodies conjugated with magnetic beads. Mouse peritoneal macrophages were incubated with isolated CM-Rs and stained with Oil-red O. Lipoprotein profiles of isolated human CM-Rs and mouse CMs collected from the intestinal lymph were examined by high performance liquid chromatography and proteomic analyses were performed by mass spectrometry using Synapt G2 HDMS PRO.
Results: Compared with the lipoprotein profile of postprandial serum, particle size of isolated lipoproteins varied in size from small chylomicrons to large LDL, which suggested CM-Rs. When incubated with isolated CM-Rs, foam cell formation of mouse peritoneal macrophages was observed. By proteomic analysis, isolated human CM-Rs and mouse CMs contained a variety of complements (C3, C4 and more), apolipoproteins (apoB, apoA2, apoD and apoH), paraoxonase 1 (PON-1) and many serine protease inhibitors.
Conclusions: The current study has demonstrated for the first time that human CM-Rs and CMs have an atherogenic nature and contain many types of complements, apolipoproteins, PON-1 and serine protease inhibitors.
Author Disclosures: D. Masuda: Research Grant; Modest; Fuji Rebio Company(Joint Research). T. Kobayashi: None. M. Okubo: None. T. Okada: None. H. Nakaoka: None. R. Kawase: Research Grant; Significant; Shionogi & Co., Ltd. : FLASH2012. Other Research Support; Significant; Otsuka Pharmaceutical Co., Ltd.. K. Nakatani: None. T. Ohama: None. M. Koseki: None. H. Hanada: None. M. Nishida: None. Y. Sakata: None. S. Yamashita: Research Grant; Modest; Fuji Rebio Company(Joint Research).
- © 2014 by American Heart Association, Inc.