Published online before print October 7, 2004, doi: 10.1161/01.RES.0000146946.78540.46
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Submitted on October 24, 2003
Revised on September 13, 2004
Accepted on September 24, 2004
Disruption of Autosomal Recessive Hypercholesterolemia Gene Shows Different Phenotype In Vitro and In Vivo
Mariko Harada-Shiba *;
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.
* To whom correspondence should be addressed. 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-/-[supi]-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:
 |
|
 |
|
  S. Poirier, G. Mayer, V. Poupon, P. S. McPherson, R. Desjardins, K. Ly, M.-C. Asselin, R. Day, F. J. Duclos, M. Witmer, et al. Dissection of the Endogenous Cellular Pathways of PCSK9-induced Low Density Lipoprotein Receptor Degradation: EVIDENCE FOR AN INTRACELLULAR ROUTE J. Biol. Chem., October 16, 2009; 284(42): 28856 - 28864. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
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]
|
|