Overexpression of apolipoprotein F reduces HDL cholesterol levels in vivo.
OBJECTIVE
Apolipoprotein F (ApoF) is a protein component of several lipoprotein classes including HDL. It is also known as lipid transfer inhibitor protein (LTIP) based on its ability to inhibit lipid transfer between lipoproteins ex vivo. We sought to investigate the role of ApoF in HDL metabolism.


RESULTS
Adeno-associated viruses (AAV) based on serotype 8, were used to overexpress either murine or human ApoF in mice. Overexpression of murine ApoF significantly reduced total cholesterol levels by 28% (P<0.001), HDL by 27% (P<0.001), and phospholipid levels by 19% (P<0.001). Overexpression of human ApoF had similar effects. Human ApoF was nearly exclusively HDL-associated in mice. In agreement with this finding, greater than 90% of the ApoF in human plasma was found on HDL(3), with only a small amount on LDL. Overexpression of mouse ApoF accelerated the plasma clearance of [(3)H]-cholesteryl ether labeled HDL. Plasma from mice overexpressing ApoF showed improved macrophage cholesterol efflux on a per HDL-C basis.


CONCLUSIONS
ApoF overexpression reduces HDL cholesterol levels in mice by increasing clearance of HDL-CE. ApoF may be an important determinant of HDL metabolism and reverse cholesterol transport.
Lagor
William R
WR
Institute for Translational Medicine and Therapeutics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
Brown
Robert J
RJ
Toh
Sue-Anne
SA
Millar
John S
JS
Fuki
Ilia V
IV
de la Llera-Moya
Margarita
M
Yuen
Tiffany
T
Rothblat
George
G
Billheimer
Jeffrey T
JT
Rader
Daniel J
DJ
D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001053:Apolipoproteins / Q000097:blood / Q000235:genetics*; D001853:Bone Marrow / Q000502:physiology; D002460:Cell Line; D002784:Cholesterol / Q000097:blood / Q000378:metabolism; D008076:Cholesterol, HDL / Q000097:blood*; D003001:Cloning, Molecular; D000229:Dependovirus / Q000235:genetics; D005786:Gene Expression Regulation; D006801:Humans; D007668:Kidney / Q000196:embryology; D008264:Macrophages / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010743:Phospholipids / Q000097:blood; D010957:Plasmids; D014280:Triglycerides / Q000097:blood
D001053:Apolipoproteins; D008076:Cholesterol, HDL; D010743:Phospholipids; D014280:Triglycerides; C036321:apolipoprotein F; D002784:Cholesterol; D000410:Alanine Transaminase