PCSK9 is not involved in the degradation of LDL receptors and BACE1 in the adult mouse brain

Mali Liu, Guoxin Wu, Jennifer Baysarowich, Michael Kavana, George H. Addona, Kathleen K. Bierilo, John S. Mudgett, Guillaume Pavlovic, Ayesha Sitlani, John J. Renger, Brian K. Hubbard, Timothy S. Fisher, Celina V. Zerbinatti

Research output: Contribution to journalArticlepeer-review

79 Scopus citations

Abstract

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a secreted protein that regulates hepatic low-density lipoprotein receptor (LDLR) levels in humans. PCSK9 has also been shown to regulate the levels of additional membrane-bound proteins in vitro, including the very low-density lipoprotein receptor (VLDLR), apolipoprotein E receptor 2 (ApoER2) and the β-site amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1), which are all highly expressed in the CNS and have been implicated in Alzheimer's disease. To better understand the role of PCSK9 in regulating these additional target proteins in vivo, their steady-state levels were measured in the brain of wild-type, PCSK9-deficient, and human PCSK9 overexpressing transgenic mice. We found that while PCSK9 directly bound to recombinant LDLR, VLDLR, and apoER2 protein in vitro, changes in PCSK9 expression did not alter the level of these receptors in the mouse brain. In addition, we found no evidence that PCSK9 regulates BACE1 levels or APP processing in the mouse brain. In conclusion, our results suggest that while PCSK9 plays an important role in regulating circulating LDL cholesterol levels by reducing the number of hepatic LDLRs, it does not appear to modulate the levels of LDLR and other membrane-bound proteins in the adult mouse brain.

Original languageEnglish (US)
Pages (from-to)2611-2618
Number of pages8
JournalJournal of Lipid Research
Volume51
Issue number9
DOIs
StatePublished - Sep 2010
Externally publishedYes

Keywords

  • β-site amyloid precursor protein-cleaving enzyme 1
  • Alzheimer's disease
  • Amyloid-β
  • Atherosclerosis
  • Low-density lipoprotein
  • Proprotein convertase subtilisin/kexin type 9

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology
  • Cell Biology

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