In vivo evidence for a role of adipose tissue SR-BI in the nutritional and hormonal regulation of adiposity and cholesterol homeostasis.
OBJECTIVE
This study examines the role of insulin and angiotensin II in high-density lipoprotein (HDL) metabolism by focusing on the regulation and function of scavenger receptor type-BI (SR-BI) in adipose tissue.


RESULTS
Insulin or angiotensin II injection in wild-type mice induced a decrease in circulating HDL and it was associated with the translocation of SR-BI from intracellular sites to the plasma membrane of adipose tissue. Refeeding upregulated adipose HDL selective cholesteryl esters uptake and SR-BI proteins through transcriptional and posttranscriptional mechanisms. This occurred along with a decrease in serum HDL and an increase in adipose cholesterol content. Similar results were obtained with transgenic mice overexpressing locally angiotensinogen in adipose tissue. In adipose 3T3-L1 cell line, HDL induced lipogenesis by increasing liver X receptor binding activity. This mechanism was dependent of insulin and angiotensin II.


CONCLUSIONS
Our results raise the possibility that adipose tissue SR-BI translocation might be a link between adipose tissue lipid storage and HDL clearance.
Yvan-Charvet
Laurent
L
INSERM, U671, Centre Biomédical des Cordeliers, 75270 Paris Cedex 06, France. ly2159@columbia.edu
Bobard
Alexandre
A
Bossard
Pascale
P
Massiéra
Florence
F
Rousset
Xavier
X
Ailhaud
Gérard
G
Teboul
Michèle
M
Ferré
Pascal
P
Dagher
Georges
G
Quignard-Boulangé
Annie
A
D041721:3T3-L1 Cells; D064286:ATP Binding Cassette Transporter 1; D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism; D000273:Adipose Tissue / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D050154:Adiposity / Q000187:drug effects / Q000235:genetics; D000804:Angiotensin II / Q000378:metabolism* / Q000494:pharmacology; D000808:Angiotensinogen / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002784:Cholesterol / Q000031:analogs & derivatives / Q000378:metabolism; D008076:Cholesterol, HDL / Q000097:blood / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D004435:Eating; D004822:Epididymis / Q000378:metabolism; D006706:Homeostasis; D007328:Insulin / Q000378:metabolism* / Q000494:pharmacology; D050155:Lipogenesis / Q000187:drug effects / Q000235:genetics; D000071518:Liver X Receptors; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D057093:Orphan Nuclear Receptors; D021381:Protein Transport; D012333:RNA, Messenger / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D051122:Scavenger Receptors, Class B / Q000235:genetics / Q000378:metabolism*; D051780:Sterol Regulatory Element Binding Protein 1 / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014158:Transcription, Genetic; D014280:Triglycerides / Q000378:metabolism
D064286:ATP Binding Cassette Transporter 1; D018528:ATP-Binding Cassette Transporters; D008076:Cholesterol, HDL; D004268:DNA-Binding Proteins; D007328:Insulin; D000071518:Liver X Receptors; D057093:Orphan Nuclear Receptors; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; C454739:Scarb1 protein, mouse; D051122:Scavenger Receptors, Class B; C497388:Srebf1 protein, mouse; D051780:Sterol Regulatory Element Binding Protein 1; D014280:Triglycerides; D000808:Angiotensinogen; D000804:Angiotensin II; C023511:cholesteryl oleyl ether; D002784:Cholesterol