Journal of Neurochemistry
Volume 89 Page 24 - April 2004
doi:10.1046/j.1471-4159.2003.02305.x
Volume 89 Issue 1


HMG-CoA reductase inhibition causes neurite loss by interfering with geranylgeranylpyrophosphate synthesis
Joachim G. Schulz, Julian Bösel, Magali Stoeckel, Dirk Megow, Ulrich Dirnagl and Matthias Endres
Abstract

To determine whether neurite outgrowth depends upon the mevalonate pathway, we blocked mevalonate synthesis in nerve growth factor-treated PC12 cells or primary cortical neurones with atorvastatin, a 3-hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, and substituted different intermediates of the mevalonate pathway. We show that HMG-CoA reductase inhibition causes a profound reduction of neurite length, neurite loss and ultimatively cell death in undifferentiated and pre-differentiated PC12 cells and also in rat primary cortical neurones. Geranylgeranylpyrophosphate, but not farnesylpyrophosphate, squalene or cholesterol, completely compensated for the lack of mevalonate. Our data indicate that, under HMG-CoA reductase inhibition, geranylgeranylpyrophosphate rather than farnesylpyrophosphate or cholesterol is critical for neurite outgrowth and/or maintenance. Loss of neurites is an early manifestation of various neurodegenerative disorders, and dysfunction of isoprenylation might play a role in their pathogenesis.

#2:
Neurodegenerative Disorders and Cholesterol
Author: Makoto Michikawa1

Source: Current Alzheimer Research, Volume 1, Number 4, November 2004, pp. 271-275(5)

Abstract:

It has been suggested that a high serum cholesterol level is a risk factor for Alzheimer's disease (AD), that treatment with cholesterol-lowering drugs (statins) reduces the frequency of AD development, and that the polymorpholism of genes encoding proteins regulating cholesterol metabolism is associated with the frequency of AD development. However, the mechanism by which high serum cholesterol level leads to AD, still remains unclarified. Several recent studies have shown the results challenging the above notions. Here another notion is proposed, that is, a low high-density lipoprotein (HDL) level in serum and cerebro-spinal fluid (CSF) is a risk factor for the development of AD; moreover, the possibility that AD and Niemann-Pick type C disease share a common cascade, by which altered cholesterol metabolism leads to neurodegeneration (tauopathy) is discussed. In this review, the association between cholesterol and AD pathogenesis is discussed from different viewpoints and several basic issues are delineated and addressed to fully understand the mechanisms underlying this relationship.