A targeted mutation in the murine gene encoding the high density lipoprotein (HDL) receptor scavenger receptor class B type I reveals its key role in HDL metabolism

Attilio Rigotti1, Bernardo L. Trigatti1, Marsha Penman1, Helen Rayburn1, Joachim Herz1, Monty Krieger1
1Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139; and Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75235

Tóm tắt

Plasma high density lipoprotein (HDL), which protects against atherosclerosis, is thought to remove cholesterol from peripheral tissues and to deliver cholesteryl esters via a selective uptake pathway to the liver (reverse cholesterol transport) and steroidogenic tissues (e.g., adrenal gland for storage and hormone synthesis). Despite its physiologic and pathophysiologic importance, the cellular metabolism of HDL has not been well defined. The class B, type I scavenger receptor (SR-BI) has been proposed to play an important role in HDL metabolism because ( i ) it is a cell surface HDL receptor which mediates selective cholesterol uptake in cultured cells, ( ii ) its physiologically regulated expression is most abundant in the liver and steroidogenic tissues, and ( iii ) hepatic overexpression dramatically lowers plasma HDL. To test directly the normal role of SR-BI in HDL metabolism, we generated mice with a targeted null mutation in the SR-BI gene. In heterozygous and homozygous mutants relative to wild-type controls, plasma cholesterol concentrations were increased by ≈31% and 125%, respectively, because of the formation of large, apolipoprotein A-I (apoA-I)-containing particles, and adrenal gland cholesterol content decreased by 42% and 72%, respectively. The plasma concentration of apoA-I, the major protein in HDL, was unchanged in the mutants. This, in conjunction with the increased lipoprotein size, suggests that the increased plasma cholesterol in the mutants was due to decreased selective cholesterol uptake. These results provide strong support for the proposal that in mice the gene encoding SR-BI plays a key role in determining the levels of plasma lipoprotein cholesterol (primarily HDL) and the accumulation of cholesterol stores in the adrenal gland. If it has a similar role in controlling plasma HDL in humans, SR-BI may influence the development and progression of atherosclerosis and may be an attractive candidate for therapeutic intervention in this disease.

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Tài liệu tham khảo

10.1016/S0022-2275(20)37713-0

10.1172/JCI114722

10.1056/NEJM198911093211907

10.1016/0005-2760(91)90132-2

10.1016/0925-4439(94)90069-8

10.1016/S0022-2275(20)39898-9

10.1016/S0022-2275(20)37453-8

10.1016/S0022-2275(20)36957-1

10.1210/edrv-3-3-299

10.1016/0163-7827(94)00007-9

10.1073/pnas.80.17.5435

10.1016/S0021-9258(20)71160-9

10.1146/annurev.cb.01.110185.000245

S D Turley, J M Dietschy The Liver: Biology and Pathobiology, eds I M Arias, W B Jakoby, H Popper, D Schachter, D A Schafritz (Raven, New York), pp. 617–641 (1988).

10.1016/S0022-2275(20)43114-1

J L Breslow The Metabolic and Molecular Bases of Inherited Diseases, eds C R Scriver, A L Beaudet, W S Sly, D Valle (McGraw–Hill, New York), pp. 2031–2052 (1995).

10.1016/S0021-9258(17)31921-X

10.1126/science.271.5248.518

10.1097/00041433-199706000-00009

10.1016/S0022-2275(20)37413-7

10.1074/jbc.272.20.13242

10.1172/JCI118883

10.1074/jbc.272.28.17551

10.1172/JCI119334

10.1074/jbc.271.52.33545

10.1074/jbc.271.35.21001

10.1074/jbc.272.25.15777

10.1038/387414a0

10.1016/0092-8674(91)90499-O

10.1038/336348a0

10.1016/0076-6879(94)45021-8

10.1016/S0091-679X(08)60610-X

T C Doetschman, H Eistetter, M Katz, W Schmidt, R Kemler J Embryol Exp Morphol 87, 27–45 (1985).

10.1093/nar/19.15.4293

10.1016/S0021-9258(18)47209-2

10.1038/227680a0

10.1073/pnas.76.9.4350

10.1074/jbc.271.19.11191

10.1016/S0021-9258(19)52451-6

10.1038/ng0596-54

10.1126/science.2244210

10.1126/science.7515194

10.1126/science.8332912

10.1073/pnas.92.12.5266

10.1016/S0022-2275(20)37431-9

10.1074/jbc.270.20.12269

10.1016/S0022-2275(20)39973-9

10.1161/01.ATV.13.12.1814

10.1016/S0022-2275(20)37227-8

10.1172/JCI116663

10.1172/JCI118716

10.1074/jbc.271.27.16208

10.1073/pnas.93.24.14041

M S Brown, P T Kovanen, J L Goldstein Rec Prog Horm Res 35, 215–257 (1979).

10.1073/pnas.93.25.14788

10.1126/science.273.5277.966

10.1073/pnas.92.5.1774

10.1172/JCI118269

10.1016/S0021-9258(17)31559-4

10.1126/science.1411543

10.1172/JCI118319

10.1074/jbc.272.11.7506

10.1074/jbc.271.42.25981

10.1172/JCI119050

10.1097/00041433-199606000-00002

10.1016/S0021-9258(17)46716-0

10.1073/pnas.94.9.4532

10.1073/pnas.93.21.11448

Temel R. Trigatt B. L. De Mattos R. Azhar S. Krieger M. & Williams D. (1997) Proc. Natl. Acad. Sci. USA in press.