Wild-type PCSK9 inhibits LDL clearance but does not affect apoB-containing lipoprotein production in mouse and cultured cells

Abstract

Mutations in Proprotein Convertase Subtilisin Kexin 9 (PCSK9) have been associated with autosomal dominant hypercholesterolemia. In vivo kinetic studies indicate that LDL catabolism was impaired and apolipoprotein B (apoB)-containing lipoprotein synthesis was enhanced in two patients presenting with the S127R mutation on PCSK9. To understand the physiological role of PCSK9, we overexpressed human PCSK9 in mouse and cellular models as well as attenuated the endogenous expression of PCSK9 in HuH7 hepatoma cells using RNA interference. Here, we show that PCSK9 dramatically impairs the expression of the low density lipoprotein receptor (LDLr) and, in turn, LDL cellular binding as well as LDL clearance from the in in role PCSK9 in the of the In in patients presenting with that PCSK9 the of in cells we show that PCSK9 in the S127R mutation in patients of in Mutations in Proprotein Convertase Subtilisin Kexin 9 (PCSK9) have been associated with autosomal dominant hypercholesterolemia. In vivo kinetic studies indicate that LDL catabolism was impaired and apolipoprotein B (apoB)-containing lipoprotein synthesis was enhanced in two patients presenting with the S127R mutation on PCSK9. To understand the physiological role of PCSK9, we overexpressed human PCSK9 in mouse and cellular models as well as attenuated the endogenous expression of PCSK9 in HuH7 hepatoma cells using RNA interference. Here, we show that PCSK9 dramatically impairs the expression of the low density lipoprotein receptor (LDLr) and, in turn, LDL cellular binding as well as LDL clearance from the in in role PCSK9 in the of the In in patients presenting with that PCSK9 the of in cells we show that PCSK9 in the S127R mutation in patients of in dominant associated with in in the of LDL and of in the low density lipoprotein receptor (LDLr) and in and of in the binding of apolipoprotein apolipoprotein B mutation and apolipoprotein the and the of and LDL and of human apolipoprotein Proprotein Convertase Subtilisin Kexin 9 (PCSK9) been as the in autosomal dominant in PCSK9 autosomal dominant PCSK9 as and Proprotein in the of of of as as and Proprotein and of in the PCSK9 the of the and of of PCSK9 expression in role PCSK9 in and in of been that expression of PCSK9 in in in associated with PCSK9 the expression of the and, in turn, LDL in cells and and on the low density lipoprotein receptor and LDL expression of in in lipoprotein receptor of kinetic studies of in patients the S127R mutation in PCSK9. studies indicate that the S127R mutation in PCSK9 associated with of as well as LDL in in that PCSK9 on synthesis and catabolism in the role of PCSK9, we overexpressed human PCSK9 in as well as overexpressed attenuated PCSK9 expression in HuH7 hepatoma cells and the catabolism of LDL and the endogenous synthesis of in show that PCSK9 and that PCSK9 expression and in and and PCSK9 with and was human PCSK9 and and the of the of the and on in and and with and with the from the and of was and in and was from of mouse in and was of the of with and and was and the and of the with and in the was in using that of the associated with was from the the using with the and in the of of the with clearance in from mouse and of human apolipoprotein in low density lipoprotein of was in of was and from from of lipoprotein on of apolipoprotein B in and from two patients with the S127R PCSK9 mutation in in was and density using and from mouse from patients as the of density the receptor was in the as in in was as lipoprotein with and and in and cells in and was and of of on in was using the and with receptor B mouse and cellular using the human as well as the as the of PCSK9 mouse as using the and using the and in RNA was using the and as well as was with using of human PCSK9 was using and the and in cells low density lipoprotein in density of cells on and the with human PCSK9 RNA using the in cells with and with in and in with and in and In of the cells in LDL binding cells on with and in with and in and the of the was of with and in the the of and the and on and with and with of and with with and two with and the in of and and the was and using the cells with in of and the and was using of the and as using PCSK9 expression in of expression of PCSK9 in of was of using that and human expression of from mouse of and with two of the using that the human PCSK9 that in mouse human PCSK9 and LDL catabolism in of of and of and in PCSK9 with the expression of the To the of the from and in the in the LDL and density lipoprotein with To the in with we the expression of two lipoprotein and expression of the was dramatically in the of the expression of the receptor To the in PCSK9, we and in the of and of with in as well as the of with of with and 9 the in PCSK9 was associated with in the of and, of in apolipoprotein of in with the of the and of the indicate that expression of PCSK9 in in of and associated with in the expression of the of and of density low density lipoprotein PCSK9, Proprotein Convertase Subtilisin Kexin in To the PCSK9 LDL in we of kinetic of LDL of mouse was the of and the of was with clearance of In the catabolism of was in with and with with PCSK9 the clearance of in in that PCSK9 in expression and in of LDL in and with the with and the of the was in from as and with with and with and in HuH7 the role of PCSK9, we in in the human hepatoma HuH7 using RNA in of human PCSK9 in HuH7 endogenous PCSK9 and PCSK9 of human PCSK9 in HuH7 and of human PCSK9 the of the human PCSK9 of human PCSK9 endogenous expression of the in HuH7 the of PCSK9 on in HuH7 attenuated PCSK9. of the was the cellular binding of PCSK9 in of human PCSK9 binding of PCSK9 expression in HuH7 hepatoma cells with RNA human PCSK9 with human as of PCSK9 and in HuH7 cells with with PCSK9 of in HuH7 cells with PCSK9 binding HuH7 cells with human PCSK9 of the binding from in as of the PCSK9 lipoprotein we the of in with was in the of was in PCSK9 In the was in and in with of in with and as of in HuH7 cells with kinetic in HuH7 cells HuH7 cells with PCSK9 In B and as of of two of from patients presenting with the S127R mutation in PCSK9 and and LDL and PCSK9 synthesis and in we in studies in HuH7 cells attenuated PCSK9. PCSK9 synthesis and of role in we the that PCSK9 on using of HuH7 cells PCSK9. 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receptor on the of in in expression and PCSK9 in that patients presenting with the S127R mutation on PCSK9 have in patients and in and patients and we the human of PCSK9. on the of PCSK9 the of mutation on of the in patients with the of the in the the S127R mutation of the in of from the in dominant associated with in in the of LDL and of in the low density lipoprotein receptor (LDLr) and in and of in the binding of apolipoprotein apolipoprotein B mutation and apolipoprotein the and the of and LDL and of human apolipoprotein Proprotein Convertase Subtilisin Kexin 9 (PCSK9) been as the in autosomal dominant in PCSK9 autosomal dominant PCSK9 as and Proprotein in the of of of as as and Proprotein and of in the PCSK9 the of the and of of PCSK9 expression in role PCSK9 in and in of been that expression of PCSK9 in in in associated with PCSK9 the expression of the and, in turn, LDL in cells and and on the low density lipoprotein receptor and LDL expression of in in lipoprotein receptor of kinetic studies of in patients the S127R mutation in PCSK9. studies indicate that the S127R mutation in PCSK9 associated with of as well as LDL in in that PCSK9 on synthesis and catabolism in To the role of PCSK9, we overexpressed human PCSK9 in as well as overexpressed attenuated PCSK9 expression in HuH7 hepatoma cells and the catabolism of LDL and the endogenous synthesis of in show that PCSK9 and that PCSK9 expression and in and and PCSK9 with and was human PCSK9 and and the of the of the and on in and and with and with the from the and of was and in and was from of mouse in and was of the of with and and was and the and of the with and in the was in using that of the associated with was from the the using with the and in the of of the with clearance in from mouse and of human apolipoprotein in low density lipoprotein of was in of was and from from of lipoprotein on of apolipoprotein B in and from two patients with the S127R PCSK9 mutation in in was and density using and from mouse 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