Serum amyloid A promotes ABCA1-dependent and ABCA1-independent lipid efflux from cells

JA Stonik, AT Remaley, SJ Demosky… - Biochemical and …, 2004 - Elsevier
JA Stonik, AT Remaley, SJ Demosky, EB Neufeld, A Bocharov, HB Brewer
Biochemical and biophysical research communications, 2004Elsevier
Serum amyloid A (SAA) is an acute phase protein that associates with HDL. In order to
examine the role of SAA in reverse-cholesterol transport, lipid efflux was tested to SAA from
HeLa cells before and after transfection with the ABCA1 transporter. ABCA1 expression
increased efflux of cholesterol and phospholipid to SAA by 3-fold and 2-fold, respectively. In
contrast to apoA-I, SAA also removed lipid without ABCA1; cholesterol efflux from control
cells to SAA was 10-fold higher than for apoA-I. Furthermore, SAA effluxed cholesterol from …
Serum amyloid A (SAA) is an acute phase protein that associates with HDL. In order to examine the role of SAA in reverse-cholesterol transport, lipid efflux was tested to SAA from HeLa cells before and after transfection with the ABCA1 transporter. ABCA1 expression increased efflux of cholesterol and phospholipid to SAA by 3-fold and 2-fold, respectively. In contrast to apoA-I, SAA also removed lipid without ABCA1; cholesterol efflux from control cells to SAA was 10-fold higher than for apoA-I. Furthermore, SAA effluxed cholesterol from Tangier disease fibroblasts and from cells after inhibition of ABCA1 by fixation with paraformaldehyde. In summary, SAA can act as a lipid acceptor for ABCA1, but unlike apoA-I, it can also efflux lipid without ABCA1, by most likely a detergent-like extraction process. These results suggest that SAA may play a unique role as an auxiliary lipid acceptor in the removal of lipid from sites of inflammation.
Elsevier