This Article Full Text Full Text (PDF) Data Supplement All Versions of this Article: 95/9/945    most recent 01.RES.0000146946.78540.46v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Harada-Shiba, M. Articles by Yokoyama, S. Search for Related Content PubMed PubMed Citation Articles by Harada-Shiba, M. Articles by Yokoyama, S. Related Collections Lipid and lipoprotein metabolism Genetically altered mice

(Circulation Research. 2004;95:945.)
© 2004 American Heart Association, Inc.

Integrative Physiology

Disruption of Autosomal Recessive Hypercholesterolemia Gene Shows Different Phenotype In Vitro and In Vivo

Mariko Harada-Shiba, Atsuko Takagi, Kousuke Marutsuka, Sayaka Moriguchi, Hiroaki Yagyu, Shun Ishibashi, Yujiro Asada, Shinji Yokoyama

From the Department of Bioscience (M.H.-S.), Department of Pharmacology (A.T.), National Cardiovascular Center Research Institute, Osaka; First Department of Pathology (K.M., S.M., Y.A.), Miyazaki Medical College, Miyazaki; Division of Endocrinology and Metabolism (H.Y., S.I.), Jichi Medical School, Kawachi-gun, Tochigi; Department of Biochemistry, Cell Biology, and Metabolism (S.Y.), Nagoya City University Graduate School of Medical Sciences, Mizuho-cho, Nagoya, Aichi, Japan.

Correspondence to Mariko Harada-Shiba, Department of Bioscience, National Cardiovascular Center Research Institute, Fujishiro-dai, Suita, Osaka 565-8565, Japan. E-mail mshiba{at}ri.ncvc.go.jp

We previously characterized the patients with autosomal recessive hypercholesterolemia (ARH) as having severe hypercholesterolemia and retarded plasma low-density lipoprotein (LDL) clearance despite normal LDL receptor (LDLR) function in their cultured fibroblasts, and we identified a mutation in the ARH locus in these patients. ARH protein is an adaptor protein of the LDL and reportedly modulates its internalization. We developed ARH knockout mice (ARH^–/–) to study the function of this protein. Plasma total cholesterol level was higher in ARH^–/– mice than that in wild-type mice (ARH^+/+), being attributed to a 6-fold increase of LDL, whereas plasma lipoprotein was normal in the heterozygotes (ARH^+/–). Clearance of ¹²⁵I-LDL from plasma was retarded in ARH^–/– mice, as much as that found in LDLR^–/– mice. Fluorescence activity of the intravenously injected 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI)-LDL was recovered in the cytosol of the hepatocytes of ARH^+/+ mice, but not in those of ARH^–/– or LDLR^–/– mice. Also, less radioactivity was recovered in the liver of ARH^–/– or LDLR^–/– mice when [³H]cholesteryl oleyl ether (CE)-labeled LDL was injected. In contrast, uptakes of [³H]CE-labeled LDL, ¹²⁵I-LDL, and DiI-LDL were all normal or slightly subnormal when the ARH^–/– hepatocytes were cultured. We thus concluded that the function of the hepatic LDLR is impaired in the ARH^–/– mice in vivo, despite its normal function in vitro. These findings were consistent with the observations with the ARH homozygous patients and suggested that certain cellular environmental factors modulate the requirement of ARH for the LDLR function.

Key Words: autosomal recessive hypercholesterolemia • knockout mouse • low-density lipoprotein receptor • primary cultured hepatocytes • OmniBank

This article has been cited by other articles:

				M. I. Sirinian, F. Belleudi, F. Campagna, M. Ceridono, T. Garofalo, F. Quagliarini, R. Verna, S. Calandra, S. Bertolini, M. Sorice, et al. Adaptor Protein ARH Is Recruited to the Plasma Membrane by Low Density Lipoprotein (LDL) Binding and Modulates Endocytosis of the LDL/LDL Receptor Complex in Hepatocytes J. Biol. Chem., November 18, 2005; 280(46): 38416 - 38423. [Abstract] [Full Text] [PDF]