scholarly journals Single-cell Individual Complete mtDNA Sequencing Uncovers Hidden Mitochondrial Heterogeneity in Human and Mouse Oocytes

2020 ◽  
Author(s):  
Chongwei Bi ◽  
Lin Wang ◽  
Yong Fan ◽  
Gerardo Ramos-Mandujano ◽  
Baolei Yuan ◽  
...  

AbstractThe ontogeny and dynamics of mtDNA heteroplasmy remain unclear due to limitations of current mtDNA sequencing methods. We developed individual Mitochondrial Genome sequencing (iMiGseq) of full-length mtDNA for ultra-sensitive variant detection, complete haplotyping, and unbiased evaluation of heteroplasmy levels, all at the individual mtDNA molecule level. iMiGseq uncovers unappreciated levels of heteroplasmic variants in single healthy human oocytes well below the current 1% detection limit, of which numerous variants are detrimental and could contribute to late-onset mitochondrial disease and cancer. Extreme mtDNA heterogeneity among oocytes of the same mouse female, and a strong selection against deleterious mutations in human oocytes are observed. iMiGseq could comprehensively characterize and haplotype single-nucleotide and structural variants of mtDNA and their genetic linkage in NARP/Leigh syndrome patient-derived cells. Therefore, iMiGseq could not only elucidate the mitochondrial etiology of diseases, but also help diagnose and prevent mitochondrial diseases with unprecedented precision.

2020 ◽  
Vol 41 (2) ◽  
pp. 134-140
Author(s):  
Yuriy Bisyuk ◽  
Andrew Dubovyi ◽  
Ilona DuBuske ◽  
Viktor Litus ◽  
Lawrence M. DuBuske

Background: This study assessed gene polymorphisms of the CD14 receptor (C-159T) and Toll-like receptor 4 (Asp299Gly) in a patient population in Crimea, Ukraine, stratified by clinical (early versus late onset; frequent versus occasional relapses; fixed versus reversible obstruction) and immunologic (atopic versus nonatopic; eosinophilic; neutrophilic or paucigranulocytic inflammation) subtype. Methods: Two polymorphisms, CD14 C-159T and TLR4 Asp299Gly, were assessed in 331 patients with asthma. The control group included 285 volunteers who were nonatopic. The single nucleotide polymorphisms were studied by using polymerase chain reaction with electrophoretic detection. Results: There were increased odds of asthma development in patients with the Asp299Gly TLR4 mutation compared with the general population underdominant odds ratio (OR) 1.52 [95% confidence interval (CI), 1.00‐2.32] and overdominant (OR 1.55 [95% CI, 1.01‐2.38]) models after adjustment for gender and age. In addition, mutations in this gene decreased the odds of nonatopic asthma in underdominant (OR 0.26 [95% CI, 0.07‐0.93]; p = 0.027), overdominant (OR 0.27 [95% CI, 0.07‐0.96]; p = 0.033), and log-additive models (OR 0.26 [95% CI, 0.07‐0.93]; p = 0.026) compared with the atopic subgroup after adjustment for gender, age, number of exacerbations, and type of airway inflammation. Allele frequencies for CD14 and TLR4 polymorphisms did not show statistical differences between the patients with asthma and the control subjects. Conclusion: CD14 C-159T polymorphisms were not associated with asthma in the adult population in Crimea. TLR4 Asp299Gly polymorphisms were associated with asthma and with decreased odds of nonatopic asthma compared with atopic asthma in the adult population in Crimea.


2020 ◽  
Vol 58 (11) ◽  
pp. 1809-1817
Author(s):  
Miaomiao Du ◽  
Xiujuan Wei ◽  
Pu Xu ◽  
Anran Xie ◽  
Xiyue Zhou ◽  
...  

AbstractObjectivesLeigh syndrome (LS) is one of the most common mitochondrial diseases and has variable clinical symptoms. However, the genetic variant spectrum of this disease is incomplete.MethodsNext-generation sequencing (NGS) was used to identify the m.14430A > G (p.W82R) variant in a patient with LS. The pathogenesis of this novel complex I (CI) variant was verified by determining the mitochondrial respiration, assembly of CI, ATP, MMP and lactate production, and cell growth rate in cybrids with and without this variant.ResultsA novel m.14430A > G (p.W82R) variant in the NADH dehydrogenase 6 (ND6) gene was identified in the patient; the mutant loads of m.14430A > G (p.W82R) in the patient were much higher than those in his mother. Although the transmitochondrial cybrid-based study showed that mitochondrial CI assembly remains unaffected in cells with the m.14430G variant, control cells had significantly higher endogenous and CI-dependent mitochondrial respiration than mutant cells. Accordingly, mutant cells had a lower ATP, MMP and higher extracellular lactate production than control cells. Notably, mutant cells had impaired growth in a galactose-containing medium when compared to wild-type cells.ConclusionsA novel m.14430A > G (p.W82R) variant in the ND6 gene was identified from a patient suspected to have LS, and this variant impaired mitochondrial respiration by decreasing the activity of mitochondrial CI.


2005 ◽  
Vol 5 (4) ◽  
pp. 275-279 ◽  
Author(s):  
Abdulaziz Ali A. Al-Khedhai ◽  
Misbahul Arfin . ◽  
Bassam A. Alahmadi . ◽  
Mohamed A. Al-Jumah .

2018 ◽  
Vol 2018 ◽  
pp. 1-4 ◽  
Author(s):  
C. Simoncini ◽  
V. Montano ◽  
G. Alì ◽  
R. Costa ◽  
G. Siciliano ◽  
...  

Mitochondrial (mt) tRNA (MTT) gene mutations are an important cause of mitochondrial diseases and are associated with a wide range of clinical presentations. Most mutations fall into three mitochondrial tRNAs (tRNAIle, tRNALeu (UUR), and tRNALys) and are responsible for half of the mitochondrial diseasees associated with tRNA mutation, with MERRF, MELAS, mitochondrial myopathy, and Leigh syndrome being the most frequent phenotypes. More than 100 tRNA pathogenetic mutations are described, showing little correlation between the observed clinical phenotype and a specific mitochondrial tRNA mutation. Furthermore different mutation can manifest with similar clinical phenotypes, making the genotype-phenotype correlation difficult. Here we report the case of an Italian 53-year-old woman presenting with a proximal myopathy and the m.5835G>A mutation in MT-TY gene coding for the mitochondrial tRNA Tyrosine gene.


The identification of a DNA restriction fragment length polymorphism closely linked to Huntington’s disease on the short arm of chromosome 4 has for the first time allowed presymptomatic prediction to be undertaken in first-degree relatives at risk. The late and variable onset of this dominantly inherited disorder makes such prediction a powerful and potentially valuable aid in genetic counselling, but in the absence of effective therapy there are serious ethical reservations concerning such a predictive test. The new developments have stimulated an active and informative debate among professionals and family members on whether and how predictive tests should be used. Guidelines have emerged which should be useful not only for Huntington’s disease, but for other serious late-onset neurogenetic disorders. Meanwhile, studies in Wales and elsewhere have not only confirmed the original linkage but have excluded multi-locus heterogeneity as a significant problem. Genetic prediction for the individual at risk remains critically dependent on a suitable family structure, present in only a minority of families in Wales. A more feasible alternative for most families is prenatal exclusion, which can allow risk prediction for a pregnancy without altering the situation for the person at risk. This approach has already been applied in Wales; the experience gained will be useful in full prediction, which is currently being introduced.


2019 ◽  
Vol 28 (R2) ◽  
pp. R197-R206 ◽  
Author(s):  
Michael A Lodato ◽  
Christopher A Walsh

AbstractAging is a mysterious process, not only controlled genetically but also subject to random damage that can accumulate over time. While DNA damage and subsequent mutation in somatic cells were first proposed as drivers of aging more than 60 years ago, whether and to what degree these processes shape the neuronal genome in the human brain could not be tested until recent technological breakthroughs related to single-cell whole-genome sequencing. Indeed, somatic single-nucleotide variants (SNVs) increase with age in the human brain, in a somewhat stochastic process that may nonetheless be controlled by underlying genetic programs. Evidence from the literature suggests that in addition to demonstrated increases in somatic SNVs during aging in normal brains, somatic mutation may also play a role in late-onset, sporadic neurodegenerative diseases, such as Alzheimer’s disease and Parkinson’s disease. In this review, we will discuss somatic mutation in the human brain, mechanisms by which somatic mutations occur and can be controlled, and how this process can impact human health.


2019 ◽  
Vol 30 (11) ◽  
pp. 2159-2176 ◽  
Author(s):  
Zhenyuan Yu ◽  
Jinling Liao ◽  
Yang Chen ◽  
Chunlin Zou ◽  
Haiying Zhang ◽  
...  

BackgroundHaving a comprehensive map of the cellular anatomy of the normal human bladder is vital to understanding the cellular origins of benign bladder disease and bladder cancer.MethodsWe used single-cell RNA sequencing (scRNA-seq) of 12,423 cells from healthy human bladder tissue samples taken from patients with bladder cancer and 12,884 cells from mouse bladders to classify bladder cell types and their underlying functions.ResultsWe created a single-cell transcriptomic map of human and mouse bladders, including 16 clusters of human bladder cells and 15 clusters of mouse bladder cells. The homology and heterogeneity of human and mouse bladder cell types were compared and both conservative and heterogeneous aspects of human and mouse bladder evolution were identified. We also discovered two novel types of human bladder cells. One type is ADRA2A+ and HRH2+ interstitial cells which may be associated with nerve conduction and allergic reactions. The other type is TNNT1+ epithelial cells that may be involved with bladder emptying. We verify these TNNT1+ epithelial cells also occur in rat and mouse bladders.ConclusionsThis transcriptomic map provides a resource for studying bladder cell types, specific cell markers, signaling receptors, and genes that will help us to learn more about the relationship between bladder cell types and diseases.


1985 ◽  
Vol 224 (1236) ◽  
pp. 315-323 ◽  

A single nucleotide substitution in a highly conserved region of the mitochondrial genome of a mouse cell line confers both chloramphenicol resistance and an alteration to the recognition site for the endonuclease Eco RV. This has enabled a detailed study on the effects of selection on a mitochondrial population comprising initially both chloramphenicol-resistant and chloramphenicol-sensitive mitochondrial genomes. The mutation confers advantage to cells grown in the presence of chloram­phenicol, but is apparently deleterious in its absence. Selection at the cellular level is sufficient to explain the results observed. Fixation, which results in cells having mitochondria of only a single type, is slow. It is probable, therefore, that mammalian oocyte mitochondria are derived from only a small number of progenitors. This would allow fixation of new mutations and explain the observed uniformity in mitochondrial genomes of the individual in the presence of extensive variation between different members of the population.


2017 ◽  
Vol 29 (7) ◽  
pp. 1115-1120
Author(s):  
Dita Pelnena ◽  
Birute Burnyte ◽  
Eriks Jankevics ◽  
Baiba Lace ◽  
Evelina Dagyte ◽  
...  

2003 ◽  
Vol 34 (2) ◽  
pp. 138-153 ◽  
Author(s):  
A. Lynn Williams ◽  
Mary Elbert

Purpose: This study involved prospective longitudinal data on 5 late talkers to provide information about the course of phonological development in order to identify possible predictors of delayed versus deviant development. Method: Five children (3 boys, 2 girls) were identified as late talkers and divided into a younger group and an older group. Each child was followed monthly for 10 to 12 months (22–33 months for the younger group and 30–42 months for the older group). Two types of monthly language samples (free play and elicited) were obtained to describe the individual courses of phonological development for each child. Independent and relational analyses were completed at each age to describe word-initial and word-final phonetic inventories, syllable structure, syllable diversity, percentage of consonants correct (PCC), sound variability, and error patterns. Results: The results indicated that 3 of the children resolved their late onset of speech by 33 to 35 months of age. In addition to quantitative factors, (e.g., limited phonetic inventory, lower PCC, and more sound errors), qualitative variables (e.g., atypical error patterns, greater sound variability, and slower rate of resolution) also were identified as potential markers of long-term phonological delay. Clinical Implications: This study provides information to clinicians so they can identify those children who are less likely to resolve their late onset of phonological development without direct intervention. Procedures are described for assessing early linguistic behaviors that incorporate independent and relational analyses on more extensive speech samples (elicited and free play). From these analyses, clinicians can examine quantitative and qualitative variables to differentiate phonological delay from deviance.


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