Neumann, M.A.C.* ; Grossmann, D.* ; Schimpf-Linzenbold, S.* ; Dayan, D.* ; Stingl, K.* ; Ben-Menachem, R.* ; Pines, O.* ; Massart, F.* ; Delcambre, S.* ; Ghelfi, J.* ; Bohler, J.* ; Strom, T.M. ; Kessel, A.* ; Azem, A.* ; Schöls, L.* ; Grünewald, A.* ; Wissinger, B.* ; Krüger, R.*
     
 
    
        
Haploinsufficiency due to a novel ACO2 deletion causes mitochondrial dysfunction in fibroblasts from a patient with dominant optic nerve atrophy.
    
    
        
    
    
        
        Sci. Rep. 10:16736 (2020)
    
    
    
		
		
			
				ACO2 is a mitochondrial protein, which is critically involved in the function of the tricarboxylic acid cycle (TCA), the maintenance of iron homeostasis, oxidative stress defense and the integrity of mitochondrial DNA (mtDNA). Mutations in the ACO2 gene were identified in patients suffering from a broad range of symptoms, including optic nerve atrophy, cortical atrophy, cerebellar atrophy, hypotonia, seizures and intellectual disabilities. In the present study, we identified a heterozygous 51 bp deletion (c.1699_1749del51) in ACO2 in a family with autosomal dominant inherited isolated optic atrophy. A complementation assay using aco1-deficient yeast revealed a growth defect for the mutant ACO2 variant substantiating a pathogenic effect of the deletion. We used patient-derived fibroblasts to characterize cellular phenotypes and found a decrease of ACO2 protein levels, while ACO2 enzyme activity was not affected compared to two age- and gender-matched control lines. Several parameters of mitochondrial function, including mitochondrial morphology, mitochondrial membrane potential or mitochondrial superoxide production, were not changed under baseline conditions. However, basal respiration, maximal respiration, and spare respiratory capacity were reduced in mutant cells. Furthermore, we observed a reduction of mtDNA copy number and reduced mtDNA transcription levels in ACO2-mutant fibroblasts. Inducing oxidative stress led to an increased susceptibility for cell death in ACO2-mutant fibroblasts compared to controls. Our study reveals that a monoallelic mutation in ACO2 is sufficient to promote mitochondrial dysfunction and increased vulnerability to oxidative stress as main drivers of cell death related to optic nerve atrophy.
			
			
				
			
		 
		
			
				
					
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        Publikationstyp
        Artikel: Journalartikel
    
 
    
        Dokumenttyp
        Wissenschaftlicher Artikel
    
 
    
        Typ der Hochschulschrift
        
    
 
    
        Herausgeber
        
    
    
        Schlagwörter
        Iron-sulfur Cluster; Metabolic-regulation; Oxidative Damage; Opa1 Isoforms; Dna Depletion; Aconitase; Protein; Neuropathy; Mutations; Alignment
    
 
    
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        Sprache
        englisch
    
 
    
        Veröffentlichungsjahr
        2020
    
 
    
        Prepublished im Jahr 
        
    
 
    
        HGF-Berichtsjahr
        2020
    
 
    
    
        ISSN (print) / ISBN
        2045-2322
    
 
    
        e-ISSN
        2045-2322
    
 
    
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	    Band: 10,  
	    Heft: 1,  
	    Seiten: ,  
	    Artikelnummer: 16736 
	    Supplement: ,  
	
    
 
  
        
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            Verlag
            Nature Publishing Group
        
 
        
            Verlagsort
            London
        
 
	
        
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        Begutachtungsstatus
        Peer reviewed
    
 
     
    
        POF Topic(s)
        30501 - Systemic Analysis of Genetic and Environmental Factors that Impact Health
    
 
    
        Forschungsfeld(er)
        Genetics and Epidemiology
    
 
    
        PSP-Element(e)
        G-500700-001
    
 
    
        Förderungen
        Israel Science Foundation
FNR within the ATTRACT program
German Research Council as part of a joint research project "TreatOPON"
Federal Ministry for Education and Research (BMBF)
European Union's (EU) Horizon2020 research and innovation program (WIDESPREAD; CENTRE-PD)
German Research Council
Fonds National de la Recherche de Luxembourg (FNR; NCER-PD)
Fonds National de la Recherche de Luxembourg (FNR; PEARL )
    
 
    
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        Erfassungsdatum
        2020-11-16