Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Defective Mitophagy in XPA via PARP1 activation and NAD+/SIRT1-depletion: Implications for neurodegeneration (mouse)

ABSTRACT: Mitochondrial dysfunction is a common feature in neurodegeneration and aging. We identify mitochondrial dysfunction in xeroderma pigmentosum group A (XPA), a nucleotide excision DNA repair disorder with severe neurodegeneration, in silico and in vivo. XPA deficient cells show defective mitophagy with excessive cleavage of PINK1 and increased mitochondrial membrane potential. The mitochondrial abnormalities appear to be caused by decreased activation of the NAD+-SIRT1-PGC-1? axis triggered by hyperactivation of the DNA damage sensor PARP1. This phenotype is rescued by PARP1 inhibition or by supplementation with NAD+ precursors that also rescue the lifespan defect in xpa-1 nematodes. Importantly, this pathogenesis appears common to ataxia-telangiectasia and Cockayne syndrome, two other DNA repair disorders with neurodegeneration, but absent in XPC, a DNA repair disorder without neurodegeneration. Our findings reveal a novel nuclear-mitochondrial cross-talk that is critical for the maintenance of mitochondrial health. Mice carrying WT, or CX (Csa-/-/Xpa-/-) alleles in a C57BL/6 background were maintained under standard laboratory conditions and allowed free access to water and control casein pelleted diet (Research Diets D12450B). At 3 months of age, 3 replicates of each of the CX and WT mice were given subcutaneous interscapular injections of 500 mg of Nicotinamide riboside/kg body weight/day or the equivalent volume of saline for 14 consecutive days at 4:00 pm. On day 15, the mice were sacrificed and half of the cerebellum was harvested for purification of mitochondria, with the left half snap-frozen, homogenized, and aliquoted for RNA isolation. Total RNA extraction was done using a TRIzol Plus RNA purification kit as per manufacturer’s protocol. Quality and quantity of the total RNA was tested using the Agilent 2100 Bio-Analyzer and RNA 6000 nano kits. The RNA was labeled using the standard Illumina protocol and hybed overnight to Mouse Ref-8 Illumina arrays. The arrays were scanned using the Beadstation 500 X from Illumina.

ORGANISM(S): Mus musculus

SUBMITTER: Kevin Becker

PROVIDER: E-GEOD-55485 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Defective mitophagy in XPA via PARP-1 hyperactivation and NAD(+)/SIRT1 reduction.

Fang Evandro Fei EF Scheibye-Knudsen Morten M Brace Lear E LE Kassahun Henok H SenGupta Tanima T Nilsen Hilde H Mitchell James R JR Croteau Deborah L DL Bohr Vilhelm A VA

Cell 20140501 4

Mitochondrial dysfunction is a common feature in neurodegeneration and aging. We identify mitochondrial dysfunction in xeroderma pigmentosum group A (XPA), a nucleotide excision DNA repair disorder with severe neurodegeneration, in silico and in vivo. XPA-deficient cells show defective mitophagy with excessive cleavage of PINK1 and increased mitochondrial membrane potential. The mitochondrial abnormalities appear to be caused by decreased activation of the NAD(+)-SIRT1-PGC-1α axis triggered by h ...[more]

PMID: 24813611

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Project description:Cockayne syndrome (CS) is an accelerated aging disorder characterized by progressive neurodegeneration caused by mutations in the genes encoding the DNA repair proteins CSA or CSB. Csbm/m mice were given a high-fat, caloric-restricted or resveratrol-supplemented diet. The high-fat diet rescued the phenotype of Csbm/m mice at the metabolic, transcriptomic and behavioral levels. Additional analysis suggests that the premature aging seen in CS mice, nematodes and human cells results from aberrant PARP activation due to deficient DNA repair leading to decreased SIRT1 activity and mitochondrial dysfunction. Notably, Î²-hydroxybutyrate levels are increased by the high-fat diet; and Î²-hydroxybutyrate, PARP inhibition, or NAD+ supplementation can activate SIRT1 and rescue CS-associated phenotypes. Mechanistically, CSB is able to displace activated PARP1 from damaged DNA to limit its activity. This study connects two emerging longevity metabolites, Î²-hydroxybutyrate and NAD+, through the deacetylase SIRT1 and suggests possible interventions for CS. 4-month-old mice, WT and Csbm/m on a C57BL/6 background, were fed a standard AIN-93G diet (SD; carbohydrate:protein:fat ratio of 64:19:17 percent of kcal) ad libitum or at 40% CR, a SD supplemented with 100 mg/kgchow resveratrol ad libitum, or a high-fat diet ad libitum consisting of AIN-93G with 60% of calories from fat, primarily hydrogenated coconut oil (HFD; carbohydrate:protein:fat ratio of 16:23:61). Each group was on the specified diet for 8 months, after which the mice were sacrificed and the cerebellum was removed. For nicotinamide treatments, 4- or 18-month-old WT and Csbm/m mice were given daily injections of nicotinamide riboside (NR) (500 mg/kg/d, ip) or saline for one week, after which the mice were sacrificed and the cerebellum was removed. RNA was extracted from the cerebellums of all mice using Trizol, and RNA quality and quantity were tested using an Agilent 2100 BioAnalyzer with RNA 6000 nano chips. RNA was labeled using the standard Illumina protocol for Illumina TotalPrep RNA Amplification Kit. Labeled RNA was hybridized to Illumina's Sentrix MouseRef-8 v2 Expression BeadChips (Illumina, San Diego, CA) overnight and washed, stained and scanned the next day.

Dataset Information

Defective Mitophagy in XPA via PARP1 activation and NAD+/SIRT1-depletion: Implications for neurodegeneration (mouse)

Publications

Defective mitophagy in XPA via PARP-1 hyperactivation and NAD(+)/SIRT1 reduction.

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