Decreased plasma cholesterol and hypersensitivity to statins in mice lacking Pcsk9.
PCSK9 encodes proprotein convertase subtilisin/kexin type 9a (PCSK9), a member of the proteinase K subfamily of subtilases. Missense mutations in PCSK9 cause an autosomal dominant form of hypercholesterolemia in humans, likely due to a gain-of-function mechanism because overexpression of either WT or mutant PCSK9 reduces hepatic LDL receptor protein (LDLR) in mice. Here, we show that livers of knockout mice lacking PCSK9 manifest increased LDLR protein but not mRNA. Increased LDLR protein led to increased clearance of circulating lipoproteins and decreased plasma cholesterol levels (46 mg/dl in Pcsk9(-/-) mice versus 96 mg/dl in WT mice). Statins, a class of drugs that inhibit cholesterol synthesis, increase expression of sterol regulatory element-binding protein-2 (SREBP-2), a transcription factor that activates both the Ldlr and Pcsk9 genes. Statin administration to Pcsk9(-/-) mice produced an exaggerated increase in LDLRs in liver and enhanced LDL clearance from plasma. These data demonstrate that PCSK9 regulates the amount of LDLR protein in liver and suggest that inhibitors of PCSK9 may act synergistically with statins to enhance LDLRs and reduce plasma cholesterol.
Rashid
Shirya
S
Department of Molecular Genetics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9046, USA.
Curtis
David E
DE
Garuti
Rita
R
Anderson
Norma N
NN
Bashmakov
Yuriy
Y
Ho
Y K
YK
Hammer
Robert E
RE
Moon
Young-Ah
YA
Horton
Jay D
JD
D000821:Animal Feed; D000818:Animals; D001055:Apolipoproteins B / Q000097:blood / Q000378:metabolism; D002478:Cells, Cultured; D002784:Cholesterol / Q000097:blood* / Q000378:metabolism; D004357:Drug Synergism; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D017353:Gene Deletion; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology*; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008148:Lovastatin / Q000494:pharmacology; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D010641:Phenotype; D000071449:Proprotein Convertase 9; D043484:Proprotein Convertases; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011973:Receptors, LDL / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D012697:Serine Endopeptidases / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism
D001055:Apolipoproteins B; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D012333:RNA, Messenger; D011973:Receptors, LDL; D002784:Cholesterol; D008148:Lovastatin; C472126:Pcsk9 protein, mouse; D000071449:Proprotein Convertase 9; D043484:Proprotein Convertases; D012697:Serine Endopeptidases