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OXPHOS remodeling in high-grade prostate cancer involves mtDNA mutations and increased succinate oxidation.
Schöpf, B, Weissensteiner, H, Schäfer, G, Fazzini, F, Charoentong, P, Naschberger, A, Rupp, B, Fendt, L, Bukur, V, Giese, I, et al
Nature communications. 2020;(1):1487
Abstract
Rewiring of energy metabolism and adaptation of mitochondria are considered to impact on prostate cancer development and progression. Here, we report on mitochondrial respiration, DNA mutations and gene expression in paired benign/malignant human prostate tissue samples. Results reveal reduced respiratory capacities with NADH-pathway substrates glutamate and malate in malignant tissue and a significant metabolic shift towards higher succinate oxidation, particularly in high-grade tumors. The load of potentially deleterious mitochondrial-DNA mutations is higher in tumors and associated with unfavorable risk factors. High levels of potentially deleterious mutations in mitochondrial Complex I-encoding genes are associated with a 70% reduction in NADH-pathway capacity and compensation by increased succinate-pathway capacity. Structural analyses of these mutations reveal amino acid alterations leading to potentially deleterious effects on Complex I, supporting a causal relationship. A metagene signature extracted from the transcriptome of tumor samples exhibiting a severe mitochondrial phenotype enables identification of tumors with shorter survival times.
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Mitochondrial Inheritance in Phytopathogenic Fungi-Everything Is Known, or Is It?
Mendoza, H, Perlin, MH, Schirawski, J
International journal of molecular sciences. 2020;(11)
Abstract
Mitochondria are important organelles in eukaryotes that provide energy for cellular processes. Their function is highly conserved and depends on the expression of nuclear encoded genes and genes encoded in the organellar genome. Mitochondrial DNA replication is independent of the replication control of nuclear DNA and as such, mitochondria may behave as selfish elements, so they need to be controlled, maintained and reliably inherited to progeny. Phytopathogenic fungi meet with special environmental challenges within the plant host that might depend on and influence mitochondrial functions and services. We find that this topic is basically unexplored in the literature, so this review largely depends on work published in other systems. In trying to answer elemental questions on mitochondrial functioning, we aim to introduce the aspect of mitochondrial functions and services to the study of plant-microbe-interactions and stimulate phytopathologists to consider research on this important organelle in their future projects.
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Mitochondrial DNA 10158T>C mutation in a patient with mitochondrial encephalomyopathy with lactic acidosis, and stroke-like episodes syndrome: A case-report and literature review (CARE-complaint).
Wang, S, Song, T, Wang, S
Medicine. 2020;(24):e20310
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Abstract
RATIONALE Mitochondrial encephalomyopathy with lactic acidosis and stroke- like episodes (MELAS) syndrome is caused by mitochondrial respiratory chain dysfunction and oxidative phosphorylation disorder. It is a rare clinical metabolic disease involved with multiple systems. PATIENT CONCERNS A 22-year-old patient presented with limb convulsion accompanied by loss of consciousness, headache, partial blindness, blurred vision, and so on. DIAGNOSES Brain magnetic resonance imaging showed a high-intensity area in bilateral occipital cortex, left parietal lobe and cerebellum on diffusion-weighted imaging. These focus did not distribute as vascular territory. The pathological examination of skeletal muscle revealed several succinate dehydrogenase reactive vessels with overreaction and increased content of lipid droplets in some muscle fibers. Genetic testing showed that the patient carried m.10158T>C mutation. INTERVENTIONS She was provided with traditional arginine hydrochloride therapy and orally medication of coenzyme Q (10 mg). OUTCOMES Mitochondrial DNA of blood and hair follicle of patient carried m.10158T>C mutation LESSONS For the suspected patients of MELAS syndrome, if the hot-spot mutation test is negative, more detection sites should be selected.
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Analysis of mitochondrial DNA allelic changes in Parkinson's disease: a preliminary study.
Casoli, T, Lisa, R, Fabbietti, P, Conti, F
Aging clinical and experimental research. 2020;(2):345-349
Abstract
BACKGROUND Mitochondrial DNA (mtDNA) mutations are considered as a possible primary cause of age-associated neurodegenerative disorders like Parkinson's disease (PD). AIMS To analyze, along the whole mtDNA sequence of PD patients, the presence of non-reference alleles compared to reference alleles, as defined in the revised Cambridge Reference Sequence (rCRS). METHODS mtDNA was extracted from whole blood of PD and control groups, and was sequenced using a chip-based resequencing system. RESULTS 58 nucleotide positions (np) exhibited a different allelic distribution in the two groups; in 81% of them the non-reference alleles were over-represented in PD patients, similar to findings reported in patients with Alzheimer's disease, albeit in reduced proportion. Closer analysis of the 58 np in PD group showed that they were characterized by low-level heteroplasmy, and that the nucleotide substitutions determined an amino acid change in 84% of cases. CONCLUSIONS These results suggest that mtDNA allelic changes are increased in PD and that age-related neurodegenerative diseases could share a common mechanism involving mtDNA.
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A Pilot Study on the Effects of l-Carnitine and Trimethylamine-N-Oxide on Platelet Mitochondrial DNA Methylation and CVD Biomarkers in Aged Women.
Bordoni, L, Sawicka, AK, Szarmach, A, Winklewski, PJ, Olek, RA, Gabbianelli, R
International journal of molecular sciences. 2020;(3)
Abstract
l-carnitine supplementation has been used for cardiovascular health protection for a long time. Recently, trimethylamine-N-oxide (TMAO), which is an end product of l-carnitine metabolism via the activity of microbiota, has been identified as a cardiovascular disease (CVD) biomarker. The aim of this study was to assess the effect of 6 months of l-carnitine supplementation in a group of aged women engaged in a regular physical training. Platelet mitochondrial DNA methylation, an emerging and innovative biomarker, lipid profile and TMAO levels have been measured. TMAO increased after l-carnitine supplementation (before 344.3 ± 129.8 ng/mL vs. after 2216.8 ± 1869.0 ng/mL; n = 9; paired t-test, p = 0.02). No significant effects on TMAO were exerted by training alone (n = 9) or by l-leucine supplementation (n = 12). TMAO levels after 6 months of l-carnitine supplementation were associated with higher low-density lipoprotein-cholesterol (LDL-c) (Spearman Rho = 0.518, p = 0.003) and total cholesterol (TC) (Spearman Rho = 0.407, p = 0.026) levels. l-carnitine supplementation increased D-loop methylation in platelets (+6.63%; paired t-test, p = 0.005). D-loop methylation was not directly correlated to the TMAO augmentation observed in the supplemented group, but its increase inversely correlated with TC (Pearson coefficient = -0.529, p = 0.029) and LDL-c (Pearson coefficient = -0.439, p = 0.048). This evidence supports the hypothesis that the correlation between l-carnitine, TMAO and atherosclerosis might be more complex than already postulated, and the alteration of mitochondrial DNA (mtDNA) methylation in platelets could be involved in the pathogenesis of this multifactorial disease.
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Association of Folate Metabolites and Mitochondrial Function in Peripheral Blood Cells in Alzheimer's Disease: A Matched Case-Control Study.
Lv, X, Zhou, D, Ge, B, Chen, H, Du, Y, Liu, S, Ji, Y, Sun, C, Wang, G, Gao, Y, et al
Journal of Alzheimer's disease : JAD. 2019;(4):1133-1142
Abstract
BACKGROUND The nutrition state plays an important role in the progress of aging. Folate may play a role in protecting mitochondrial (mt) DNA by reducing oxidative stress. OBJECTIVE The primary aim of this study was to examine the association of mitochondrial oxidative damage with risk of Alzheimer's disease (AD), and to explore the possible role of folate metabolites in this association in a matched case-control study. METHODS Serum folate metabolites and mitochondrial function in peripheral blood cells were determined in 82 AD cases and 82 healthy controls, individually matched by age, gender, and education. RESULTS AD patients had lower serum levels of folate and higher homocysteine (Hcy) concentration. AD patients had a reduced mtDNA copy number, higher mtDNA deletions, and increased 8-OHdG content in mtDNA indicative of reduced mitochondrial function. The highest level of mtDNA copy number would decrease the risk of AD (OR = 0.157, 95% CI: 0.058-0.422) compared to the lowest level, independently of serum folate, and Hcy levels. Serum folate levels correlated with low 8-OHdG content in mtDNA both in AD patients and controls, independently of serum Hcy level. Moreover, serum Hcy levels correlated with low copy number in mtDNA both in AD patients and controls, independently of serum folate levels. CONCLUSION In conclusion, mitochondrial function in peripheral blood cells could be associated with risk of AD independent of multiple covariates. AD patients with a folate deficiency or hyperhomocysteinemia had low mitochondrial function in peripheral blood cells. However, further randomized controlled trials are need to determine a causal effect.
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Mitochondrial DNA, a Powerful Tool to Decipher Ancient Human Civilization from Domestication to Music, and to Uncover Historical Murder Cases.
Merheb, M, Matar, R, Hodeify, R, Siddiqui, SS, Vazhappilly, CG, Marton, J, Azharuddin, S, Al Zouabi, H
Cells. 2019;(5)
Abstract
Mitochondria are unique organelles carrying their own genetic material, independent from that in the nucleus. This review will discuss the nature of mitochondrial DNA (mtDNA) and its levels in the cell, which are the key elements to consider when trying to achieve molecular identification in ancient and degraded samples. mtDNA sequence analysis has been appropriately validated and is a consistent molecular target for the examination of biological evidence encountered in forensic cases-and profiling, in certain conditions-especially for burnt bodies and degraded samples of all types. Exceptional cases and samples will be discussed in this review, such as mtDNA from leather in Beethoven's grand piano, mtDNA in mummies, and solving famous historical criminal cases. In addition, this review will be discussing the use of ancient mtDNA to understand past human diet, to trace historical civilizations and ancient trade routes, and to uncover geographical domestication origins and lineage relationships. In each topic, we will present the power of mtDNA and how, in many cases, no nuclear DNA was left, leaving mitochondrial DNA analysis as a powerful alternative. Exploring this powerful tool further will be extremely useful to modern science and researchers, due to its capabilities in providing us with previously unattainable knowledge.
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Complex multisystem phenotype associated with the mitochondrial DNA m.5522G>A mutation.
Nesti, C, Rubegni, A, Tolomeo, D, Baldacci, J, Cassandrini, D, D'Amore, F, Santorelli, FM
Neurological sciences : official journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology. 2019;(8):1705-1708
Abstract
Mitochondrial tRNAs are responsible for more than half of pathogenic point mutations in the mitochondrial genome (mtDNA). Different mutations give rise to widely differing phenotypes, ranging from isolated organ-specific diseases to multisystem conditions. Herein, we report a 40-year-old woman presenting with a complex multisystem phenotype including sensorineural hearing loss, retinopathy, severe dilated cardiomyopathy, non-insulin dependent diabetes mellitus, and renal failure. Sequence analysis of mtDNA identified the m.5522G>A mutation in MT-TW, the gene encoding mitochondrial tRNA for tryptophan. The heteroplasmic variant, thus far described once, was almost exclusively confined to skeletal muscle tissue, as shown by massive parallel sequencing and corroborated by an ad hoc designed PCR-based strategy. This patient, presenting a severe, multisystem involvement apparently sparing the brain, contributes to the genetic heterogeneity of mitochondrial diseases caused by mutations in mitochondrial tRNAs.
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Exogenous Factors May Differentially Influence the Selective Costs of mtDNA Mutations.
Aw, WC, Garvin, MR, Ballard, JWO
Advances in anatomy, embryology, and cell biology. 2019;:51-74
Abstract
In this review, we provide evidence to suggest that the cost of specific mtDNA mutations can be influenced by exogenous factors. We focus on macronutrient-mitochondrial DNA interactions as factors that may differentially influence the consequences of a change as mitochondria must be flexible in its utilization of dietary proteins, carbohydrates, and fats. To understand this fundamental dynamic, we briefly discuss the energy processing pathways in mitochondria. Next, we explore the mitochondrial functions that are initiated during energy deficiency or when cells encounter cellular stress. We consider the anterograde response (nuclear control of mitochondrial function) and the retrograde response (nuclear changes in response to mitochondrial signaling) and how this mito-nuclear crosstalk may be influenced by exogenous factors such as temperature and diet. Finally, we employ Complex I of the mitochondrial electron transport system as a case study and discuss the potential role of the dietary macronutrient ratio as a strong selective force that may shape the frequencies of mitotypes in populations and species. We conclude that this underexplored field likely has implications in the fundamental disciplines of evolutionary biology and quantitative genetics and the more biomedical fields of nutrigenomics and pharmacogenomics.
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Associations of Mitochondrial and Nuclear Mitochondrial Variants and Genes with Seven Metabolic Traits.
Kraja, AT, Liu, C, Fetterman, JL, Graff, M, Have, CT, Gu, C, Yanek, LR, Feitosa, MF, Arking, DE, Chasman, DI, et al
American journal of human genetics. 2019;(1):112-138
Abstract
Mitochondria (MT), the major site of cellular energy production, are under dual genetic control by 37 mitochondrial DNA (mtDNA) genes and numerous nuclear genes (MT-nDNA). In the CHARGEmtDNA+ Consortium, we studied genetic associations of mtDNA and MT-nDNA associations with body mass index (BMI), waist-hip-ratio (WHR), glucose, insulin, HOMA-B, HOMA-IR, and HbA1c. This 45-cohort collaboration comprised 70,775 (insulin) to 170,202 (BMI) pan-ancestry individuals. Validation and imputation of mtDNA variants was followed by single-variant and gene-based association testing. We report two significant common variants, one in MT-ATP6 associated (p ≤ 5E-04) with WHR and one in the D-loop with glucose. Five rare variants in MT-ATP6, MT-ND5, and MT-ND6 associated with BMI, WHR, or insulin. Gene-based meta-analysis identified MT-ND3 associated with BMI (p ≤ 1E-03). We considered 2,282 MT-nDNA candidate gene associations compiled from online summary results for our traits (20 unique studies with 31 dataset consortia's genome-wide associations [GWASs]). Of these, 109 genes associated (p ≤ 1E-06) with at least 1 of our 7 traits. We assessed regulatory features of variants in the 109 genes, cis- and trans-gene expression regulation, and performed enrichment and protein-protein interactions analyses. Of the identified mtDNA and MT-nDNA genes, 79 associated with adipose measures, 49 with glucose/insulin, 13 with risk for type 2 diabetes, and 18 with cardiovascular disease, indicating for pleiotropic effects with health implications. Additionally, 21 genes related to cholesterol, suggesting additional important roles for the genes identified. Our results suggest that mtDNA and MT-nDNA genes and variants reported make important contributions to glucose and insulin metabolism, adipocyte regulation, diabetes, and cardiovascular disease.