Serum amyloid A protein generates pre beta 1 high-density lipoprotein from alpha-migrating high-density lipoprotein.
Serum amyloid A protein (SAA), an acute-phase reactant in reactive amyloidosis, has high affinity for high-density lipoprotein (HDL). When SAA is added to HDL, SAA displaces apolipoprotein A-I (apoA-I) and phospholipid from the HDL particles. These dissociated components may form prebeta1-HDL because free apoA-I can associate with phospholipid to become a lipoprotein having prebeta mobility. To determine whether SAA generates prebeta1-HDL from alpha-migrating HDL, we investigated the effects of recombinant SAA on HDL subfraction concentration using nondenaturing two-dimensional gradient gel electrophoresis. When we added SAA (0.5 mg/mL) to plasma, the prebeta1-HDL concentration increased by 164% (from 4.7% +/- 1.3% to 12.4% +/- 3.2% of apoA-I, p < 0.005). The increase in prebeta1-HDL was proportional to the dose of SAA. When we added SAA to a column of Sepharose beads coupled to the isolated HDL (alpha-migrating HDL), prebeta1-HDL was dissociated from the column together with the SAA-associated HDL. In summary, we demonstrate that SAA generates prebeta1-HDL from alpha-migrating HDL. We speculate that SAA-mediated HDL remodeling may take place in inflammation.
Miida
T
T
Department of Laboratory Medicine, First Department of Internal Medicine, Niigata University School of Medicine, Japan. miida@med.niigata-u.ac.jp
Yamada
T
T
Yamadera
T
T
Ozaki
K
K
Inano
K
K
Okada
M
M
D000328:Adult; D016632:Apolipoprotein A-I / Q000097:blood / Q000302:isolation & purification / Q000378:metabolism*; D005591:Chemical Fractionation; D002847:Chromatography, Agarose; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D053442:High-Density Lipoproteins, Pre-beta; D006801:Humans; D008075:Lipoproteins, HDL / Q000097:blood / Q000302:isolation & purification / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012685:Sepharose; D000685:Serum Amyloid A Protein / Q000378:metabolism* / Q000502:physiology
D016632:Apolipoprotein A-I; D053442:High-Density Lipoproteins, Pre-beta; D008075:Lipoproteins, HDL; D000685:Serum Amyloid A Protein; D012685:Sepharose