Neurometabolic Diseases Lab

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Galea E, Launay N, Portero-Otin M, Ruiz M, Pamplona R, Aubourg P, Ferrer I, Pujol A. Oxidative stress underlying axonal degeneration in adrenoleukodystrophy: A paradigm for multifactorial neurodegenerative diseases? Biochim Biophys Acta. 2012 Sep;1822(9):1475-88.

X-linked adrenoleukodystrophy (X-ALD) is an inherited neurodegenerative disorder expressed as four disease variants characterized by adrenal insufficiency and graded damage in the nervous system. X-ALD is caused by a loss of function of the peroxisomal ABCD1 fatty-acid transporter, resulting in the accumulation of very long chain fatty acids (VLCFA) in the organs and plasma, which have potentially toxic effects in CNS and adrenal glands. We have recently shown that treatment with a combination of antioxidants containing α-tocopherol, N-acetyl-cysteine and α-lipoic acid reversed oxidative damage and energetic failure, together with the axonal degeneration and locomotor impairment displayed by Abcd1 null mice, the animal model of X-ALD. This is the first direct demonstration that oxidative stress, which is a hallmark not only of X-ALD, but also of other neurodegenerative processes, such as Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease (HD), contributes to axonal damage. The purpose of this review is, first, to discuss the molecular and cellular underpinnings of VLCFA-induced oxidative stress, and how it interacts with energy metabolism and/or inflammation to generate a complex syndrome wherein multiple factors are contributing. Particular attention will be paid to the dysregulation of redox homeostasis by the interplay between peroxisomes and mitochondria. Second, we will extend this analysis to the aforementioned neurodegenerative diseases with the aim of defining differences as well as the existence of a core pathogenic mechanism that would justify the exchange of therapeutic opportunities among these pathologies. This article is part of a Special Issue entitled: Metabolic functions and biogenesis of peroxisomes in health and disease.

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&Featured by Faculty of 1000 (Professor Mike Johnston, Kennedy Krieger Institute and John Hopkins University Hospital).

Last Updated on Tuesday, 30 July 2013 13:36
 
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Morató L, Galino J, Ruiz M, Calingasan NY, Starkov AA, Dumont M, Naudí A, Martínez JJ, Aubourg P, Portero-Otín M, Pamplona R, Galea E, Beal MF, Ferrer I, Fourcade S, Pujol A. Pioglitazone halts axonal degeneration in a mouse model of X-linked adrenoleukodystrophy. Brain. 2013 Aug;136(Pt 8):2432-43.

X-linked adrenoleukodystrophy is a neurometabolic disorder caused by inactivation of the peroxisomal ABCD1 transporter of very long-chain fatty acids. In mice, ABCD1 loss causes late onset axonal degeneration in the spinal cord in association with locomotor disability resembling the most common phenotype in patients, adrenomyeloneuropathy. Increasing evidence indicates that oxidative stress and bioenergetic failure play major roles in the pathogenesis of X-linked adrenoleukodystrophy. In this study, we aimed to evaluate whether mitochondrial biogenesis is affected in X-linked adrenoleukodystrophy. We demonstrated that Abcd1 null mice show reduced mitochondrial DNA concomitant with downregulation of mitochondrial biogenesis pathway driven by PGC-1α/PPARγ and reduced expression of mitochondrial proteins cytochrome c, NDUFB8 and VDAC. Moreover, we show that the oral administration of pioglitazone, an agonist of PPARγ, restored mitochondrial content and expression of master regulators of biogenesis, neutralized oxidative damage to proteins and DNA, and reversed bioenergetic failure in terms of ATP levels, NAD+/NADH ratios, pyruvate kinase and glutathione reductase activities. Most importantly, the treatment halted locomotor disability and axonal damage in X-linked adrenoleukodystrophy mice. These results lend support to the use of pioglitazone in clinical trials with patients with adrenomyeloneuropathy and reveal novel molecular mechanisms of action of pioglitazone in neurodegeneration. Future studies should address the effects of this anti-diabetic drug on other axonopathies in which oxidative stress and mitochondrial dysfunction are contributing factors.

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&Scientific Commentary by Carlos Moraes, Brain July 10 2013 doi:10.1093/brain/awt189. Pdf: pdf button
&Scientific Commentary by Nature Reviews Neurology. Research Highlight. July 16 2013 doi:10.1038/nrneurol.2013.141. Pdf: pdf button

Last Updated on Monday, 31 October 2016 17:09
 
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S Fourcade, J López-Erauskin, J Galino, C Duval, A Naudi, M Jove, S Kemp, F Villarroya, I Ferrer, R Pamplona, M Portero-Otin, A Pujol (2008). Early oxidative damage underlying neurodegeneration in Xadrenoleukodystrophy. Human Molecular Genetics. Jun 15;17(12):1762-73

X-linked adrenoleukodystrophy (X-ALD) is a fatal neurodegenerative disorder, characterized by progressive cerebral demyelination cerebral childhood adrenoleukodystrophy (CCALD) or spinal cord neurodegeneration (adrenomyeloneuropathy, AMN), adrenal insufficiency and accumulation of very long-chain fatty acids (VLCFA) in tissues. The disease is caused by mutations in the ABCD1 gene, which encodes a peroxisomal transporter that plays a role in the import of VLCFA or VLCFA-CoA into peroxisomes. The Abcd1 knockout mice develop a spinal cord disease that mimics AMN in adult patients, with late onset at 20 months of age. The mechanisms underlying cerebral demyelination or axonal degeneration in spinal cord are unknown. Here, we present evidence by gas chromatography/mass spectrometry that malonaldehyde-lysine, a consequence of lipoxidative damage to proteins, accumulates in the spinal cord of Abcd1 knockout mice as early as 3.5 months of age. At 12 months, Abcd1- mice accumulate additional proteins modified by oxidative damage arising from metal-catalyzed oxidation and glycoxidation/lipoxidation. While we show that VLCFA excess activates enzymatic antioxidant defenses at the protein expression levels, both in neural tissue, in ex vivo organotypic spinal cord slices from Abcd1- mice, and in human ALD fibroblasts, we also demonstrate that the loss of Abcd1 gene function hampers oxidative stress homeostasis. We find that the alpha-tocopherol analog Trolox is able to reverse oxidative lesions in vitro, thus providing therapeutic hope. These results pave the way for the identification of therapeutic targets that could reverse the deregulated response to oxidative stress in X-ALD.


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&Featured by Faculty of 1000 (Professor George Perry, Dean of Texas University).

Last Updated on Tuesday, 30 July 2013 13:39
 


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