title: MicroRNA-33b knock-in mice for an intron of sterol regulatory element-binding factor 1 (Srebf1) exhibit reduced HDL-C in vivo.
abstract: MicroRNAs (miRs) are small non-protein-coding RNAs that bind to specific mRNAs and inhibit translation or promote mRNA degradation. Recent reports, including ours, indicated that miR-33a located within the intron of sterol regulatory element-binding protein (SREBP) 2 controls cholesterol homeostasis and can be a possible therapeutic target for treating atherosclerosis. Primates, but not rodents, express miR-33b from an intron of SREBF1. Therefore, humanized mice, in which a miR-33b transgene is inserted within a Srebf1 intron, are required to address its function in vivo. We successfully established miR-33b knock-in (KI) mice and found that protein levels of known miR-33a target genes, such as ABCA1, ABCG1, and SREBP-1, were reduced compared with those in wild-type mice. As a consequence, macrophages from the miR-33b KI mice had a reduced cholesterol efflux capacity via apoA-I and HDL-C. Moreover, HDL-C levels were reduced by almost 35% even in miR-33b KI hetero mice compared with the control mice. These results indicate that miR-33b may account for lower HDL-C levels in humans than those in mice and that miR-33b is possibly utilized for a feedback mechanism to regulate its host gene SREBF1. Our mice will also aid in elucidating the roles of miR-33a/b in different genetic disease models.
authors.affiliation: 1] Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan [2] Department of Clinical Innovative Medicine, Institute for Advancement of Clinical and Translational Science, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan [3].
authors.forename: Takahiro
authors.initials: T
authors.lastname: Horie
authors.affiliation: 1] Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan [2].
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Nishino
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Baba
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
authors.forename: Yasuhide
authors.initials: Y
authors.lastname: Kuwabara
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
authors.forename: Tetsushi
authors.initials: T
authors.lastname: Nakao
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
authors.forename: Masataka
authors.initials: M
authors.lastname: Nishiga
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Usami
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
authors.forename: Masayasu
authors.initials: M
authors.lastname: Izuhara
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
authors.forename: Fumiko
authors.initials: F
authors.lastname: Nakazeki
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
authors.forename: Yuya
authors.initials: Y
authors.lastname: Ide
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Koyama
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Sowa
authors.affiliation: Department of Internal Medicine (Endocrinology and Metabolism), Graduate School of Comprehensive Human Sciences, Nutrigenomics Research Group, Faculty of Medicine, and International Institute for Integrative Sleep Medicine (IIIS), World Premir International Research Center Initiative (WPI), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Yahagi
authors.affiliation: Department of Internal Medicine (Endocrinology and Metabolism), Graduate School of Comprehensive Human Sciences, Nutrigenomics Research Group, Faculty of Medicine, and International Institute for Integrative Sleep Medicine (IIIS), World Premir International Research Center Initiative (WPI), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Shimano
authors.affiliation: Department of Pharmacology, Kansai Medical University, Moriguchi, Osaka 570-8506, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Nakamura
authors.affiliation: Division of Translational Research, National Hospital Organization, Kyoto Medical Center, Kyoto 612-8555, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Hasegawa
authors.affiliation: Division of Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Kobe 650-8586, Japan.
authors.forename: Noriaki
authors.initials: N
authors.lastname: Kume
authors.affiliation: Department of Clinical Innovative Medicine, Institute for Advancement of Clinical and Translational Science, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yokode
authors.affiliation: Department of Cardiovascular Medicine, Kobe City Medical Center General Hospital, Kobe 650-0046, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Kita
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kimura
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
authors.forename: Koh
authors.initials: K
authors.lastname: Ono
mesh_terms: D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002478:Cells, Cultured; D008076:Cholesterol, HDL / Q000378:metabolism*; D020869:Gene Expression Profiling; D056945:Hep G2 Cells; D006801:Humans; D007438:Introns / Q000235:genetics*; D017737:Macrophages, Peritoneal / Q000378:metabolism; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D035683:MicroRNAs / Q000235:genetics*; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012689:Sequence Homology, Nucleic Acid; D051780:Sterol Regulatory Element Binding Protein 1 / Q000235:genetics* / Q000378:metabolism
chemical_list: D008076:Cholesterol, HDL; C550416:MIRN33a microRNA, human; D035683:MicroRNAs; C497387:SREBF1 protein, human; C497388:Srebf1 protein, mouse; D051780:Sterol Regulatory Element Binding Protein 1