scholarly journals Understanding mitochondrial DNA maintenance disorders at the single muscle fibre level

2019 ◽  
Vol 47 (14) ◽  
pp. 7430-7443 ◽  
Author(s):  
Diana Lehmann ◽  
Helen A L Tuppen ◽  
Georgia E Campbell ◽  
Charlotte L Alston ◽  
Conor Lawless ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Single Cell ◽  
Respiratory Chain ◽  
Genetic Defect ◽  
Clear Correlation ◽  
Muscle Fibres ◽  
Single Muscle Fibre ◽  
Respiratory Chain Deficiency ◽  
Mtdna Deletions ◽  
Mtdna Deletion

Abstract Clonal expansion of mitochondrial DNA (mtDNA) deletions is an important pathological mechanism in adults with mtDNA maintenance disorders, leading to a mosaic mitochondrial respiratory chain deficiency in skeletal muscle. This study had two aims: (i) to determine if different Mendelian mtDNA maintenance disorders showed similar pattern of mtDNA deletions and respiratory chain deficiency and (ii) to investigate the correlation between the mitochondrial genetic defect and corresponding respiratory chain deficiency. We performed a quantitative analysis of respiratory chain deficiency, at a single cell level, in a cohort of patients with mutations in mtDNA maintenance genes. Using the same tissue section, we performed laser microdissection and single cell genetic analysis to investigate the relationship between mtDNA deletion characteristics and the respiratory chain deficiency. The pattern of respiratory chain deficiency is similar with different genetic defects. We demonstrate a clear correlation between the level of mtDNA deletion and extent of respiratory chain deficiency within a single cell. Long-range and single molecule PCR shows the presence of multiple mtDNA deletions in approximately one-third of all muscle fibres. We did not detect evidence of a replicative advantage for smaller mtDNA molecules in the majority of fibres, but further analysis is needed to provide conclusive evidence.

scholarly journals Detecting respiratory chain deficiency in osteoblasts of older patients

2021 ◽  
Author(s):  
Daniel Hipps ◽  
Philip Dobson ◽  
Charlotte Warren ◽  
David McDonald ◽  
Andrew Fuller ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Mouse Model ◽  
Respiratory Chain ◽  
Nuclear Genome ◽  
Mitochondrial Dna Mutation ◽  
Human Osteoblasts ◽  
Dna Mutation ◽  
Respiratory Chain Deficiency ◽  
Age Related ◽  
Cellular Dysfunction

Mitochondria contain their own genome which encodes 13 essential mitochondrial proteins and accumulates somatic variants at up to 10 times the rate of the nuclear genome. These mitochondrial genome variants lead to respiratory chain deficiency and cellular dysfunction. Work with the PolgAmut/PolgAmut mouse model, which has a high mitochondrial DNA mutation rate, showed enhanced levels of age related osteoporosis in affected mice along with respiratory chain deficiency in osteoblasts. To explore whether respiratory chain deficiency is also seen in human osteoblasts with age, we developed a protocol and analysis framework for imaging mass cytometry (IMC) in bone tissue sections to analyse osteoblasts in situ. We have demonstrated significant increases in complex I deficiency with age in human osteoblasts. This work is consistent with findings from the PolgAmut/PolgAmut mouse model and suggests that respiratory chain deficiency, as a consequence of the accumulation of age related mitochondrial DNA mutations, may have a significant role to play in the pathogenesis of human age related osteoporosis.

scholarly journals Mechanisms of replication and repair in mitochondrial DNA deletion formation

2020 ◽  
Vol 48 (20) ◽  
pp. 11244-11258
Author(s):  
Gabriele A Fontana ◽  
Hailey L Gahlon
Keyword(s):  
Dna Damage ◽  
Mitochondrial Dna ◽  
Large Scale ◽  
Molecular Mechanisms ◽  
Mitochondrial Dna Deletion ◽  
Deletion Formation ◽  
Dna Deletion ◽  
Mtdna Deletions ◽  
Mtdna Deletion

Abstract Deletions in mitochondrial DNA (mtDNA) are associated with diverse human pathologies including cancer, aging and mitochondrial disorders. Large-scale deletions span kilobases in length and the loss of these associated genes contributes to crippled oxidative phosphorylation and overall decline in mitochondrial fitness. There is not a united view for how mtDNA deletions are generated and the molecular mechanisms underlying this process are poorly understood. This review discusses the role of replication and repair in mtDNA deletion formation as well as nucleic acid motifs such as repeats, secondary structures, and DNA damage associated with deletion formation in the mitochondrial genome. We propose that while erroneous replication and repair can separately contribute to deletion formation, crosstalk between these pathways is also involved in generating deletions.

Mitochondrial DNA Depletion is a Prevalent Cause of Multiple Respiratory Chain Deficiency in Childhood

2007 ◽  
Vol 150 (5) ◽  
pp. 531-534.e6 ◽  
Author(s):  
Emmanuelle Sarzi ◽  
Alice Bourdon ◽  
Dominique Chrétien ◽  
Mohamed Zarhrate ◽  
Johanna Corcos ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Respiratory Chain ◽  
Respiratory Chain Deficiency ◽  
Mitochondrial Dna Depletion

scholarly journals Respiratory-deficient human fibroblasts exhibiting defective mitochondrial DNA replication

1995 ◽  
Vol 305 (3) ◽  
pp. 817-822 ◽  
Author(s):  
A G Bodnar ◽  
J M Cooper ◽  
J V Leonard ◽  
A H V Schapira
Keyword(s):  
Mitochondrial Dna ◽  
Respiratory Chain ◽  
Cultured Cells ◽  
Human Fibroblasts ◽  
Genetic Defect ◽  
Mitochondrial Protein ◽  
Mitochondrial Respiratory Chain ◽  
Human Cell Line ◽  
Respiratory Chain Complexes ◽  
Respiratory Deficient

We have characterized cultured skin fibroblasts from two siblings affected with a fatal mitochondrial disease caused by a nuclear genetic defect. Mitochondrial respiratory-chain function was severely decreased in these cells. Southern-blot analysis showed that the fibroblasts had reduced levels of mitochondrial DNA (mtDNA). The mtDNA was unstable and was eliminated from the cultured cells over many generations, generating the rho0 genotype. As the mtDNA level decreased, the cells became more dependent upon pyruvate and uridine for growth. Nuclear-encoded subunits of respiratory-chain complexes were synthesized and imported into the mitochondria of the mtDNA-depleted cells, albeit at reduced levels compared with the controls. Mitochondrial protein synthesis directed by the residual mtDNA indicated that the mtDNA was expressed and that the defect specifically involves the replication or maintenance of mtDNA. This is a unique example of a respiratory-deficient human cell line exhibiting defective mtDNA replication.

scholarly journals No excess of mitochondrial DNA deletions within muscle in progressive multiple sclerosis

2013 ◽  
Vol 19 (14) ◽  
pp. 1858-1866 ◽  
Author(s):  
Graham R Campbell ◽  
Amy K Reeve ◽  
Iryna Ziabreva ◽  
Richard Reynolds ◽  
Doug M Turnbull ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Mitochondrial Dna ◽  
Mitochondrial Dysfunction ◽  
Chain Complex ◽  
Muscle Fibres ◽  
Mitochondrial Respiratory Chain Complex ◽  
Respiratory Enzyme ◽  
Mtdna Deletions ◽  
Age Related ◽  
Enzyme Deficient

Background: Mitochondrial dysfunction is an established feature of multiple sclerosis (MS). We recently described high levels of mitochondrial DNA (mtDNA) deletions within respiratory enzyme-deficient (lacking mitochondrial respiratory chain complex IV with intact complex II) neurons and choroid plexus epithelial cells in progressive MS. Objectives: The objective of this paper is to determine whether respiratory enzyme deficiency and mtDNA deletions in MS were in excess of age-related changes within muscle, which, like neurons, are post-mitotic cells that frequently harbour mtDNA deletions with ageing and in disease. Methods: In progressive MS cases ( n=17), known to harbour an excess of mtDNA deletions in the central nervous system (CNS), and controls ( n=15), we studied muscle (paraspinal) and explored mitochondria in single fibres. Histochemistry, immunohistochemistry, laser microdissection, real-time polymerase chain reaction (PCR), long-range PCR and sequencing were used to resolve the single muscle fibres. Results: The percentage of respiratory enzyme-deficient muscle fibres, mtDNA deletion level and percentage of muscle fibres harbouring high levels of mtDNA deletions were not significantly different in MS compared with controls. Conclusion: Our findings do not provide support to the existence of a diffuse mitochondrial abnormality involving multiple systems in MS. Understanding the cause(s) of the CNS mitochondrial dysfunction in progressive MS remains a research priority.

Cytoskeletal structure of myoblasts with the mitochondrial DNA 3243A→G mutation and of osteosarcoma cells with respiratory chain deficiency

2002 ◽  
Vol 53 (3) ◽  
pp. 231-238 ◽  
Author(s):  
Harri Rusanen ◽  
Johanna Annunen ◽  
Heli Ylä-Outinen ◽  
Aino Laurila ◽  
Juha Peltonen ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Respiratory Chain ◽  
Osteosarcoma Cells ◽  
Respiratory Chain Deficiency ◽  
Cytoskeletal Structure

Mitochondrial DNA-related Disorders

2007 ◽  
Vol 27 (1-3) ◽  
pp. 31-37 ◽  
Author(s):  
Michelangelo Mancuso ◽  
Massimiliano Filosto ◽  
Anna Choub ◽  
Marta Tentorio ◽  
Laura Broglio ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Mitochondrial Genome ◽  
Respiratory Chain ◽  
Nuclear Genome ◽  
Mitochondrial Diseases ◽  
Mitochondrial Respiratory Chain ◽  
Mitochondrial Genetics ◽  
Respiratory Chain Deficiency ◽  
Clinical Syndromes ◽  
Clinical Pictures

Mitochondrial diseases are a group of disorders due to a mitochondrial respiratory chain deficiency. They may depend on mitochondrial genome (mtDNA-related disorders) as well as on a nuclear genome defect (nDNA-related disorders). mtDNA-related disorders encompass an increasing number of clinical pictures associated with more than 250 different provisional or confirmed pathogenic changes in mtDNA. Although some clinical syndromes are nosologically defined, most of the cases present with polymorphous phenotypes ranging from pure myopathy to multi-system involvement. Complexity of mitochondrial genetics is in part responsible for the extreme clinical intra- and inter-familial heterogeneity of this group of diseases. In this review, we briefly report an updated classification and overview the main clinical pictures of this class of diseases.

scholarly journals Multi-Omics Approach to Mitochondrial DNA Damage in Human Muscle Fibers

2021 ◽  
Vol 22 (20) ◽  
pp. 11080
Author(s):  
Matthias Elstner ◽  
Konrad Olszewski ◽  
Holger Prokisch ◽  
Thomas Klopstock ◽  
Marta Murgia
Keyword(s):  
Mitochondrial Dna ◽  
Cell Fate ◽  
Respiratory Chain ◽  
Large Scale ◽  
Muscle Fibers ◽  
Progressive External Ophthalmoplegia ◽  
Proteomics Data ◽  
Respiratory Chain Deficiency ◽  
Mitochondrial Dna Damage ◽  
Dna Deletions

Mitochondrial DNA deletions affect energy metabolism at tissue-specific and cell-specific threshold levels, but the pathophysiological mechanisms determining cell fate remain poorly understood. Chronic progressive external ophthalmoplegia (CPEO) is caused by mtDNA deletions and characterized by a mosaic distribution of muscle fibers with defective cytochrome oxidase (COX) activity, interspersed among fibers with retained functional respiratory chain. We used diagnostic histochemistry to distinguish COX-negative from COX-positive fibers in nine muscle biopsies from CPEO patients and performed laser capture microdissection (LCM) coupled to genome-wide gene expression analysis. To gain molecular insight into the pathogenesis, we applied network and pathway analysis to highlight molecular differences of the COX-positive and COX-negative fiber transcriptome. We then integrated our results with proteomics data that we previously obtained comparing COX-positive and COX-negative fiber sections from three other patients. By virtue of the combination of LCM and a multi-omics approach, we here provide a comprehensive resource to tackle the pathogenic changes leading to progressive respiratory chain deficiency and disease in mitochondrial deletion syndromes. Our data show that COX-negative fibers upregulate transcripts involved in translational elongation and protein synthesis. Furthermore, based on functional annotation analysis, we find that mitochondrial transcripts are the most enriched among those with significantly different expression between COX-positive and COX-negative fibers, indicating that our unbiased large-scale approach resolves the core of the pathogenic changes. Further enrichments include transcripts encoding LIM domain proteins, ubiquitin ligases, proteins involved in RNA turnover, and, interestingly, cell cycle arrest and cell death. These pathways may thus have a functional association to the molecular pathogenesis of the disease. Overall, the transcriptome and proteome show a low degree of correlation in CPEO patients, suggesting a relevant contribution of post-transcriptional mechanisms in shaping this disease phenotype.

scholarly journals Thermodynamic analysis of mitochondrial DNA breakpoints reveals mechanistic details of deletion mutagenesis

2018 ◽  
Author(s):  
Lakshmi Narayanan Lakshmanan ◽  
Zhuangli Yee ◽  
Jan Gruber ◽  
Barry Halliwell ◽  
Rudiyanto Gunawan
Keyword(s):  
Mitochondrial Dna ◽  
Dna Hybridization ◽  
Double Strand Breaks ◽  
Dsb Repair ◽  
Strand Breaks ◽  
Deletion Mutations ◽  
Mtdna Deletions ◽  
Mtdna Deletion ◽  
Strand Invasion

AbstractBroad evidence support double-strand breaks (DSBs) as initiators of mitochondrial DNA (mtDNA) deletion mutations. But the mechanism of DSB-induced deletions, including the DSB repair pathway(s) involved, remains to be established. Here, we used DNA hybridization thermodynamics to analyze misalignment lengths surrounding deletion breakpoints. Our analysis of 9,655 previously reported mammalian mtDNA deletions and 1,307 novel Caenorhabditis elegans mtDNA deletions, indicates a significant role of 0–25bp misalignments, supporting the role of erroneous non-homologous and micro-homology dependent DSB repair in deletion formation. Based on these insights we propose that DSB-induced mtDNA deletions occur via the misjoining of DSB ends and/or strand invasion of open mtDNA regions by DSB ends.

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