Antioxidants halt axonal degeneration in a mouse model of X‐adrenoleukodystrophy

Abstract

ObjectiveAxonal degeneration is a main contributor to disability in progressive neurodegenerative diseases in which oxidative stress is often identified as a pathogenic factor. We aim to demonstrate that antioxidants are able to improve axonal degeneration and locomotor deficits in a mouse model of X-adrenoleukodystrophy (X-ALD).MethodsX-ALD is a lethal disease caused by loss of function of the ABCD1 peroxisomal transporter of very long chain fatty acids (VLCFA). The mouse model for X-ALD exhibits a late onset neurological phenotype with locomotor disability and axonal degeneration in spinal cord resembling the most common phenotype of the disease, adrenomyeloneuropathy (X-AMN). Recently, we identified oxidative damage as an early event in life, and the excess of VLCFA as a generator of radical oxygen species (ROS) and oxidative damage to proteins in X-ALD.ResultsHere, we prove the capability of the antioxidants N-acetyl-cysteine, α-lipoic acid, and α-tocopherol to scavenge VLCFA-dependent ROS generation in vitro. Furthermore, in a preclinical setting, the cocktail of the 3 compounds reversed: (1) oxidative stress and lesions to proteins, (2) immunohistological signs of axonal degeneration, and (3) locomotor impairment in bar cross and treadmill tests.InterpretationWe have established a direct link between oxidative stress and axonal damage in a mouse model of neurodegenerative disease. This conceptual proof of oxidative stress as a major disease-driving factor in X-AMN warrants translation into clinical trials for X-AMN, and invites assessment of antioxidant strategies in axonopathies in which oxidative damage might be a contributing factor. Ann Neurol 2011;

Activation of sirtuin 1 as therapy for the peroxisomal disease adrenoleukodystrophy

“…This model has been successfully used to assay pharmacological and gene therapeutic strategies to combat AMN. 21,24,36 We generated triple mutant mice Abcd1 − /Abcd2 −/− /SIRT1Tg, and in parallel, SIRT1 was pharmacologically activated by feeding Abcd1 − / Abcd2 −/− mice with RSV (Abcd1 − /Abcd2 −/− +RSV). Animals were then challenged with two behavioral tests.…”

“…The sections were stained with hematoxylin and eosin and Sudan black, or processed for immunohistochemistry to rabbit anti-Iba1: dilution 1/1000 (019-19741 (Wako Pure Chemicals Industries, Ltd., Osaka, Japan)); rabbit anti-glial fibrillary acidic protein (GFAP): dilution 1/300 (Z-0334 (Dako)); mouse anti-synaptophysin: dilution 1/500 (SYNAP--299-L-CE (Leica Biosystems, Nussloch, Germany)); rabbit anti-amyloid precursor protein (APP): dilution 1/100 (AHP538 (AbD Serotec, Oxford, UK)); mouse anticytochrome c: dilution 1/100 (55643 (BD Biosciences Pharmingen, San Diego, CA, USA)); mouse anti-neurofilament H non-phosphorylated (SMI32): dilution 1/3000 (SMI-32P (Covance Antibody, BioLegend, Dedham, MA, USA)); rabbit anti-MDA: dilution 1/1000. 21,24,67 The mounting medium used for the acquisitions of the images was DPX. Images were acquired with Olympus BX51 microscope (UPlan FL N 20 × /0.50 Ph1) (Olympus Corporation, Tokyo, Japan) connected to a Olympus DP71 camera and Cell^B software (Olympus Corporation).…”

“…16,17,18 These animals present a late onset axonopathy in the spinal cord, in the absence of inflammatory demyelination in the brain, resembling the spastic paraparesis and lower extremity weakness of adrenomyeloneuropathy (AMN). 18,19 We previously reported oxidative damage in spinal cords from presymptomatic Abcd1 -mice, [20][21][22] together with metabolic failure, 23 disrupted mitochondrial biogenesis 24 and impaired mitochondrial oxidative phosphorylation and function. [25][26][27] Evidences for oxidative damage in X-ALD patients are also found in brain 28 and blood samples.…”

Molecular Mechanisms and Physiological Significance of Organelle Interactions and Cooperation

“…However, here it is of interest to note that (i) the spinal cord is the main X-ALD target tissue (in man) (Berger et al, 2014), (ii) OXPHOS complexes are also severely impaired in hepatocytes isolated from liver-specific Pex5 null mice (Peeters et al, 2015), and (iii) isolated mitochondria and intact cells may respond differently to an increase in VLCFAs because these lipids also exert detrimental influence on pyridine nucleotide regeneration in the cytosol (Kruska et al, 2015). By treatment of the Abcd1 −/− mice with a mixture of antioxidants (N-acetyl-cysteine, α-lipoic acid, and α-tocopherol), oxidative stress, axonal degeneration, and locomotor impairment were reversed (López-Erauskin et al, 2011). Variable effects of VLCFAs (C24:0, C26:0) on cultured cells have been reported.…”

In vitro effect of N-acetyl-L-cysteine on glutathione and sulfhydryl levels in X-linked adrenoleukodystrophy patients

“…NAC can also reduce disulphide bonds in proteins, scavenge free radicals and bind metals to form complexes 7 . There are several in vitro and in vivo studies involving NAC action on X-ALD treatment [8][9][10][11] . Considering that NAC has been proposed as a GSH precursor, the purpose of this study was to analyze the in vitro effect of NAC on GSH and sulfhydryl levels in X-ALD patients.…”