title: New CETP inhibitor K-312 reduces PCSK9 expression: a potential effect on LDL cholesterol metabolism.
abstract: Despite significant reduction of cardiovascular events by statin treatment, substantial residual risk persists, driving emerging needs for the development of new therapies. We identified a novel cholesteryl ester transfer protein (CETP) inhibitor, K-312, that raises HDL and lowers LDL cholesterol levels in animals. K-312 also suppresses hepatocyte expression of proprotein convertase subtilisin/kexin 9 (PCSK9), a molecule that increases LDL cholesterol. We explored the underlying mechanism for the reduction of PCSK9 expression by K-312. K-312 inhibited in vitro human plasma CETP activity (IC50; 0.06 μM). Administration of K-312 to cholesterol-fed New Zealand White rabbits for 18 wk raised HDL cholesterol, decreased LDL cholesterol, and attenuated aortic atherosclerosis. Our search for additional beneficial characteristics of this compound revealed that K-312 decreases PCSK9 expression in human primary hepatocytes and in the human hepatoma cell line HepG2. siRNA silencing of CETP in HepG2 did not compromise the suppression of PCSK9 by K-312, suggesting a mechanism independent of CETP. In HepG2 cells, K-312 treatment decreased the active forms of sterol regulatory element-binding proteins (SREBP-1 and -2) that regulate promoter activity of PCSK9. Chromatin immunoprecipitation assays demonstrated that K-312 decreased the occupancy of SREBP-1 and SREBP-2 on the sterol regulatory element of the PCSK9 promoter. PCSK9 protein levels decreased by K-312 treatment in the circulating blood of cholesterol-fed rabbits, as determined by two independent mass spectrometry approaches, including the recently developed, highly sensitive parallel reaction monitoring method. New CETP inhibitor K-312 decreases LDL cholesterol and PCSK9 levels, serving as a new therapy for dyslipidemia and cardiovascular disease.
authors.affiliation: Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; and Tokyo New Drug Research Laboratories, Kowa Company, Ltd., Tokyo, Japan.
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Miyosawa
authors.affiliation: Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; and Tokyo New Drug Research Laboratories, Kowa Company, Ltd., Tokyo, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Watanabe
authors.affiliation: Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; and Tokyo New Drug Research Laboratories, Kowa Company, Ltd., Tokyo, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Murakami
authors.affiliation: Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; and Tokyo New Drug Research Laboratories, Kowa Company, Ltd., Tokyo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Murakami
authors.affiliation: Tokyo New Drug Research Laboratories, Kowa Company, Ltd., Tokyo, Japan.
authors.forename: Haruki
authors.initials: H
authors.lastname: Shibata
authors.affiliation: Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; and Tokyo New Drug Research Laboratories, Kowa Company, Ltd., Tokyo, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Iwashita
authors.affiliation: Tokyo New Drug Research Laboratories, Kowa Company, Ltd., Tokyo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yamazaki
authors.affiliation: Tokyo New Drug Research Laboratories, Kowa Company, Ltd., Tokyo, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Yamazaki
authors.affiliation: Tokyo New Drug Research Laboratories, Kowa Company, Ltd., Tokyo, Japan.
authors.forename: Tadaaki
authors.initials: T
authors.lastname: Ohgiya
authors.affiliation: Tokyo New Drug Research Laboratories, Kowa Company, Ltd., Tokyo, Japan.
authors.forename: Kimiyuki
authors.initials: K
authors.lastname: Shibuya
authors.affiliation: Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; and Tokyo New Drug Research Laboratories, Kowa Company, Ltd., Tokyo, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Mizuno
authors.affiliation: Tokyo New Drug Research Laboratories, Kowa Company, Ltd., Tokyo, Japan.
authors.forename: Sohei
authors.initials: S
authors.lastname: Tanabe
authors.affiliation: Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; and.
authors.forename: Sasha A
authors.initials: SA
authors.lastname: Singh
authors.affiliation: Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; and maikawa@rics.bwh.harvard.edu.
authors.forename: Masanori
authors.initials: M
authors.lastname: Aikawa
mesh_terms: D000818:Animals; D000924:Anticholesteremic Agents / Q000494:pharmacology*; D002478:Cells, Cultured; D053480:Cholesterol Ester Transfer Proteins / Q000037:antagonists & inhibitors*; D008078:Cholesterol, LDL / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D056945:Hep G2 Cells; D006801:Humans; D050356:Lipid Metabolism / Q000187:drug effects / Q000235:genetics; D008297:Male; D051379:Mice; D000071449:Proprotein Convertase 9; D043484:Proprotein Convertases / Q000235:genetics* / Q000378:metabolism; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D012697:Serine Endopeptidases / Q000235:genetics* / Q000378:metabolism
chemical_list: D000924:Anticholesteremic Agents; C506642:CETP protein, human; D053480:Cholesterol Ester Transfer Proteins; D008078:Cholesterol, LDL; C472125:PCSK9 protein, human; D000071449:Proprotein Convertase 9; D043484:Proprotein Convertases; D012697:Serine Endopeptidases
keywords: atherosclerosis; cholesteryl ester transfer protein; lipoproteins; mass spectrometry; parallel reaction monitoring; proprotein convertase subtilisin/kexin 9; sterol regulatory element-binding protein