scholarly journals Screening for Mitochondrial tRNA Mutations in 318 Patients with Dilated Cardiomyopathy

2022 ◽  
Author(s):  
Yujuan Qi ◽  
Zhenhua Wu ◽  
Yaobang Bai ◽  
Yan Jiao ◽  
Peijun Li
Keyword(s):  
Dilated Cardiomyopathy ◽  
Mitochondrial Dysfunction ◽  
Copy Number ◽  
Mutational Analysis ◽  
Unknown Etiology ◽  
Trna Genes ◽  
Mtdna Copy Number ◽  
Mitochondrial Trna ◽  
Mitochondrial Functions ◽  
And Gender

Objectives: Dilated cardiomyopathy (DCM) is a complex cardiovascular disease with unknown etiology. Although nuclear genes play active roles in DCM, mitochondrial dysfunction was believed to be involved in the pathogenesis of DCM. The objective of this study is to analysis the association between mitochondrial tRNA (mt-tRNA) mutations and DCM. Material and Methods: We performed a mutational analysis of mt-tRNA genes in a cohort of 318 patients with DCM and 200 age- and gender-matched control subjects. To further assess their pathogenicity, phylogenetic analysis and mitochondrial functions including mtDNA copy number, ATP and ROS were analyzed. Results: 7 possible pathogenic mutations: MT-TL1 3302A>G, MT-TI 4295A>G, MT-TM 4435A>G, MT-TA 5655T>C, MT-TH 12201T>C, MT-TE 14692A>G and MT-TT 15927G>A were identified in DCM group but absent in controls. These mutations occurred at extremely conserved nucleotides of corresponding tRNAs, and led to the failure in tRNAs metabolism. Moreover, a significant reduction in ATP and mtDNA copy number, whereas a markedly increased in ROS level were observed in polymononuclear leukocytes (PMNs) derived from the DCM patients carrying these mt-tRNA mutations, suggesting that these mutations may cause mitochondrial dysfunction that was responsible for DCM. Conclusions: Our data indicated that mt-tRNA mutations may be the molecular basis for DCM, which shaded novel insight into the pathophysiology of DCM that was manifestated by mitochondrial dysfunction.

scholarly journals Mutational Screening for Mitochondrial tRNA Mutations in 150 Children with High Myopia

2021 ◽  
Vol 31 (5) ◽  
Author(s):  
Tian Xia ◽  
Ying Pang ◽  
Huimin Xiong
Keyword(s):  
Mitochondrial Dysfunction ◽  
High Myopia ◽  
Phenotypic Expression ◽  
Active Role ◽  
Unknown Etiology ◽  
Trna Genes ◽  
Mitochondrial Translation ◽  
Mitochondrial Trna ◽  
Pathogenic Variants ◽  
Mutational Screening

Background: Myopia is a very common eye disease with an unknown etiology. Increasing evidence shows that mitochondrial dysfunction plays an active role in the pathogenesis and progression of this disease. Objectives: The purpose of this study was to analyze the relationship between mitochondrial tRNA (mt-tRNA) variants and high myopia (HM). Methods: The entire mt-tRNA genes of 150 children with HM, as well as 100 healthy subjects, were PCR-amplified and sequenced. To assess the pathogenicity, we used the phylogenetic conservation analysis and pathogenicity scoring system. Results: We identified six candidate pathogenic variants: tRNALeu (UUR) T3290C, tRNAIle A4317G, tRNAAla G5591A, tRNASer (UCN) T7501C, tRNAHis T12201C, and tRNAThr G15915A. However, these variants were not identified in controls. Further phylogenetic analysis revealed that these variants occurred at the positions, which were very evolutionarily conserved and may have structural-functional impacts on the tRNAs. Subsequently, these variants may lead to the impairment of mitochondrial translation and aggravated mitochondrial dysfunction, which play an active role in the phenotypic expression of HM. Conclusions: Our results suggested that variants in mt-tRNA genes were the risk factors for HM, which provided valuable information for the early detection and prevention of HM.

scholarly journals Reduced mtDNA Copy Number in the Prefrontal Cortex of C9ORF72 patients

2021 ◽  
Author(s):  
Maria Isabel Alvarez-Mora ◽  
Petar Podlesniy ◽  
Teresa Riazuelo ◽  
Laura Molina-Porcel ◽  
Ellen Gelpi ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Mitochondrial Dysfunction ◽  
Protein Function ◽  
Copy Number ◽  
Mtdna Copy Number ◽  
Hexanucleotide Repeat ◽  
Mitochondrial Dna Copy Number ◽  
Droplet Pcr ◽  
Mitochondrial Defects ◽  
And Gender

Abstract Hexanucleotide repeat expansion in C9ORF72 gene is the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia (C9ALS/FTD). Loss of C9ORF72 protein function and a toxic gain-of-function directly by the RNA or RAN translation have been proposed as triggering pathological mechanisms, along with the accumulation of TDP-43 protein. In addition, mitochondrial defects have been described to be a major driver of disease initiation. Mitochondrial DNA copy number has been proposed as a useful biomarker of mitochondrial dysfunction. The aim of our study was to determine the presence of mtDNA copy number alterations in C9ALS/FTD patients. Therefore, we assessed mtDNA copy number in postmortem prefrontal cortex from 18 C9ORF72 brain donors and 9 controls using digital droplet PCR. A statistically significant decrease of 50% was obtained when comparing C9ORF72 samples and controls. This decrease was independent of age and gender. The reduction of mtDNA copy number was found to be higher in patient samples presenting abundant TDP-43 protein inclusions. A growing number of studies demonstrated the influence of mtDNA copy number reduction on neurodegeneration. Our results provide new insights into the role of mitochondrial dysfunction in the pathogenesis of C9ALS/FTD.

Abstract P372: Serum From Pediatric Dilated Cardiomyopathy Patients Promotes Dysregulation Of Cardiolipin Biosynthesis And Mitochondrial Dysfunction In Primary Cardiomyocytes

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Julie Pires da Silva ◽  
Anastacia M Garcia ◽  
Carissa A Miyano ◽  
Genevieve C Sparagna ◽  
Raleigh L Jonscher ◽  
...  
Keyword(s):  
Dilated Cardiomyopathy ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Function ◽  
Copy Number ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Adult Population ◽  
Neonatal Rat ◽  
Resonance Spectroscopy ◽  
Mtdna Copy Number

Pediatric dilated cardiomyopathy (DCM) is a devastating and poorly understood disease with most clinical treatment paradigms extrapolated from the adult population. Our studies have demonstrated that aspects of metabolism and mitochondrial function are dysregulated in pediatric DCM hearts. Cardiolipin (CL), a unique phospholipid in the inner mitochondrial membrane, is essential for optimal mitochondrial function and was shown to be dysregulated in both the failing adult and pediatric human heart. The objective of this study is to investigate if serum circulating factors from pediatric DCM patients can remodel CL resulting in mitochondrial dysfunction in vitro , similar to what is observed in the failing pediatric heart. Using a novel in vitro model that consists of treating neonatal rat ventricular myocytes (NRVMs) with serum from pediatric DCM patients or from non-failing (NF) healthy controls, mitochondrial respiration was assessed using the Agilent Seahorse, and reactive oxygen species (ROS) was assessed using Electron Paramagnetic Resonance Spectroscopy. Relative mitochondrial DNA (mtDNA) copy number was determined by qPCR and expression of enzymes involved in CL biosynthesis and remodeling were analyzed using RT-qPCR. Mass-spectrometry was used to quantitate total and specific CL species and to investigate the metabolite composition of NRVMs treated with NF or DCM serum. While mitochondrial ROS and mtDNA copy number were not significantly altered, we show that DCM serum decreases mitochondrial function, which is associated with alterations in CL content and composition and the downregulation of enzymes implicated in CL biosynthesis and remodeling. Analysis of metabolite content showed an alteration of pathways involved in fatty acid metabolism, mitochondrial biogenesis and regulation of β-oxidation by the transcription factor PPARα. In conclusion, pediatric DCM serum circulating factors can promote CL remodeling resulting mitochondrial dysfunction in primary cardiomyocytes. These findings suggest that CL could be a novel therapeutic target for this particular population.

scholarly journals DNA Methylation of PGC-1α Is Associated With Elevated mtDNA Copy Number and Altered Urinary Metabolites in Autism Spectrum Disorder

2021 ◽  
Vol 9 ◽  
Author(s):  
Sophia Bam ◽  
Erin Buchanan ◽  
Caitlyn Mahony ◽  
Colleen O’Ryan
Keyword(s):  
Autism Spectrum Disorder ◽  
Dna Methylation ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Biogenesis ◽  
Mitochondrial Function ◽  
Copy Number ◽  
Autism Spectrum ◽  
Differential Methylation ◽  
Mtdna Copy Number ◽  
Key Genes

Autism spectrum disorder (ASD) is a complex disorder that is underpinned by numerous dysregulated biological pathways, including pathways that affect mitochondrial function. Epigenetic mechanisms contribute to this dysregulation and DNA methylation is an important factor in the etiology of ASD. We measured DNA methylation of peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1α), as well as five genes involved in regulating mitochondrial homeostasis to examine mitochondrial dysfunction in an ASD cohort of South African children. Using targeted Next Generation bisulfite sequencing, we found differential methylation (p < 0.05) at six key genes converging on mitochondrial biogenesis, fission and fusion in ASD, namely PGC-1α, STOML2, MFN2, FIS1, OPA1, and GABPA. PGC-1α, the transcriptional regulator of biogenesis, was significantly hypermethylated at eight CpG sites in the gene promoter, one of which contained a putative binding site for CAMP response binding element 1 (CREB1) (p = 1 × 10–6). Mitochondrial DNA (mtDNA) copy number, a marker of mitochondrial function, was elevated (p = 0.002) in ASD compared to controls and correlated significantly with DNA methylation at the PGC-1α promoter and there was a positive correlation between methylation at PGC-1α CpG#1 and mtDNA copy number (Spearman’s r = 0.2, n = 49, p = 0.04) in ASD. Furthermore, DNA methylation at PGC-1α CpG#1 and mtDNA copy number correlated significantly (p < 0.05) with levels of urinary organic acids associated with mitochondrial dysfunction, oxidative stress, and neuroendocrinology. Our data show differential methylation in ASD at six key genes converging on PGC-1α-dependent regulation of mitochondrial biogenesis and function. We demonstrate that methylation at the PGC-1α promoter is associated with elevated mtDNA copy number and metabolomic evidence of mitochondrial dysfunction in ASD. This highlights an unexplored role for DNA methylation in regulating specific pathways involved in mitochondrial biogenesis, fission and fusion contributing to mitochondrial dysfunction in ASD.

scholarly journals Mitochondrial tRNA mutations in Chinese children with tic disorders

2020 ◽  
Vol 40 (12) ◽  
Author(s):  
Peifang Jiang ◽  
Yinjie Ling ◽  
Tao Zhu ◽  
Xiaoying Luo ◽  
Yilin Tao ◽  
...  
Keyword(s):  
Mutational Analysis ◽  
Phenotypic Variability ◽  
Han Chinese ◽  
Tic Disorders ◽  
Trna Genes ◽  
Incomplete Penetrance ◽  
Mitochondrial Trna ◽  
Pathogenic Potential ◽  
Total Prevalence ◽  
Chinese Subjects

Abstract Aim: To conduct the clinical, genetic, and molecular characterization of 494 Han Chinese subjects with tic disorders (TD). Methods: In the present study, we performed the mutational analysis of 22 mitochondrial tRNA genes in a large cohort of 494 Han Chinese subjects with TD via Sanger sequencing. These variants were then assessed for their pathogenic potential via phylogenetic, functional, and structural analyses. Results: A total of 73 tRNA gene variants (49 known and 24 novel) on 22 tRNA genes were identified. Among these, 18 tRNA variants that were absent or present in <1% of 485 Chinese control patient samples were localized to highly conserved nucleotides, or changed the modified nucleotides, and had the potential structural to alter tRNA structure and function. These variants were thus considered to be TD-associated mutations. In total, 25 subjects carried one of these 18 putative TD-associated tRNA variants with the total prevalence of 4.96%. Limitations: The phenotypic variability and incomplete penetrance of tic disorders in pedigrees carrying these tRNA mutations suggested the involvement of modifier factors, such as nuclear encoded genes associated mitochondrion, mitochondrial haplotypes, epigenetic, and environmental factors. Conclusion: Our data provide the evidence that mitochondrial tRNA mutations are the important causes of tic disorders among Chinese population. These findings also advance current understanding regarding the clinical relevance of tRNA mutations, and will guide future studies aimed at elucidating the pathophysiology of maternal tic disorders.

scholarly journals Mutational Analysis of Mitochondrial tRNA Genes in 200 Patients with Type 2 Diabetes Mellitus

2021 ◽  
Vol Volume 14 ◽  
pp. 5719-5735
Author(s):  
Liangyan Lin ◽  
Dongdong Zhang ◽  
Qingsong Jin ◽  
Yaqin Teng ◽  
Xiaoyan Yao ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Type 2 Diabetes Mellitus ◽  
Mutational Analysis ◽  
Trna Genes ◽  
Mitochondrial Trna ◽  
Mitochondrial Trna Genes

86 Effect of invitro culture conditions on mitochondria functions in mouse embryos

2020 ◽  
Vol 32 (2) ◽  
pp. 169
Author(s):  
M. Czernik ◽  
D. Winiarczyk ◽  
S. Sampino ◽  
P. Greda ◽  
J. A. Modlinski ◽  
...  
Keyword(s):  
Embryo Development ◽  
Copy Number ◽  
Energy Demand ◽  
Mitochondrial Membrane ◽  
Mitochondrial Dynamics ◽  
Culture Conditions ◽  
Mouse Embryos ◽  
Mtdna Copy Number ◽  
Mitochondrial Functions ◽  
Mitochondria Functions

Mitochondria provide the energy for oocyte maturation, fertilisation, and embryo formation via oxidative phosphorylation. Consequently, any adverse influence on mitochondrial function may negatively affect the development of pre-implantation embryos especially because there is no mitochondrial DNA (mtDNA) replication until post-implantation. Studies in the field of mitochondrial dynamics have identified an intriguing link between energy demand/supply balance and mitochondrial architecture, which may suggest that inappropriate culture conditions may inhibit mitochondrial functions, which may negatively affect embryo development. We wanted to check whether invitro culture (IVC) conditions of mouse embryos affect mitochondrial functionality. The IVC as well as naturally matted (NM) mouse embryos at the 2-cell and blastocyst stage were subjected to mitochondrial analysis (distribution, organisation, and mitochondrial membrane potential), and expression of mRNA and proteins involved in regulation of mitochondria functions, as well as number of mtDNA copies, were evaluated. Significance level was set at 0.05. We observed that the mitochondria in 2-cell IVC embryos were less numerous and localised mainly in the pericortical region of the cytoplasm, whereas mitochondria in NM embryos were numerous and homogeneously distributed in both blastomeres. Drastic differences were observed in blastocysts. Mitochondria in the IVC group were fragmented, rounded, and aggregated mainly in the perinuclear region of the cells, whereas mitochondria of NM blastocysts were numerous and created an elongated mitochondrial network along the cells. Time-lapse analysis showed reduced mitochondrial and mitochondrial membrane activity in IVC blastocysts. Moreover, our results indicate the IVC group had reduced mRNA expression of mitofusin 1, mitofusin 2, and optic atrophy 1 responsible for mitochondrial fusion. Additionally, mtDNA copy number for IVC blastocysts (398 887.45±30 608.65) was significantly lower than that of NM blastocysts (593 367.12±66 540.32; P<0.02). Furthermore, no significant differences were found in mtDNA copy number of IVC 2-cell embryos when compared with NM embryos. The results obtained clearly showed that IVC conditions affect proper mitochondrial functionality and hence embryo development.

scholarly journals DNA methylation of PGC-1α is associated with elevated mtDNA copy number and altered urinary metabolites in Autism Spectrum Disorder

2021 ◽  
Author(s):  
Sophia Bam ◽  
Erin Buchanan ◽  
Caitlyn Mahony ◽  
Colleen O’Ryan
Keyword(s):  
Autism Spectrum Disorder ◽  
Dna Methylation ◽  
Mitochondrial Dysfunction ◽  
Copy Number ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Peroxisome Proliferator ◽  
Mtdna Copy Number ◽  
Cpg Sites ◽  
Mtdna Deletions

AbstractBackgroundAutism Spectrum Disorder (ASD) is a complex disorder that is underpinned by numerous dysregulated biological pathways, including canonical mitochondrial pathways. Epigenetic mechanisms contribute to this dysregulation and DNA methylation is an important factor in the aetiology of ASD. We examined the relationship between DNA methylation of peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α), an essential transcriptional regulator of mitochondrial homeostasis, and mitochondrial dysfunction in an ASD cohort of South African children.ResultsUsing targeted Next Generation bisulfite sequencing, we found 12 highly variable CpG sites in PGC-1α that were significantly differentially methylated (p<0.05) between ASD (n = 55) and controls (n = 44). In ASD, eight CpG sites were hypermethylated in the PGC-1α promotor with a putative binding site for CAMP response binding element 1 (CREB1) spanning one of these CpG sites (p = 1 × 10−6). Mitochondrial DNA (mtDNA) copy number, a marker of mitochondrial function, was elevated (p = 0.002) in ASD compared to controls and correlated significantly with DNA methylation at the PGC-1α promoter. There was a positive correlation between methylation at PGC-1α at CpG#1 and mtDNA copy number (Spearman’s r = 0.2, n = 49, p = 0.04) in ASD, but a negative correlation between methylation at PGC-1α at CpG#4 promoter and mtDNA copy number in controls (Spearman’s r = −0.4, n = 42, p = 0.045). While there was no relationship between mtDNA deletions and PGC-1α methylation in ASD, mtDNA deletions correlated negatively with methylation at PGC-1α at CpG#4 (Spearman’s r = −0.4, n = 42, p = 0.032) in controls. Furthermore, levels of urinary organic acids associated with mitochondrial dysfunction correlated significantly (p<0.05) with DNA methylation at PGC-1α CpG#1 and mtDNA copy number in ASD (n= 20) and controls (n= 13) with many of these metabolites involved in altered redox homeostasis and neuroendocrinology.ConclusionsThese data show an association between PGC-1α promoter methylation, elevated mtDNA copy number and metabolomic evidence of mitochondrial dysfunction in ASD. This highlights an unexplored link between DNA methylation and mitochondrial dysfunction in ASD.

scholarly journals Intronic tRNAs of mitochondrial origin regulate constitutive and alternative splicing

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Simon M. Hoser ◽  
Anne Hoffmann ◽  
Andreas Meindl ◽  
Maximilian Gamper ◽  
Jörg Fallmann ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Human Genome ◽  
Splice Site ◽  
Mutational Analysis ◽  
Mitochondrial Protein ◽  
Regulatory Elements ◽  
Trna Genes ◽  
Mitochondrial Trna ◽  
Mobility Shift ◽  
Cloverleaf Structure

Abstract Background The presence of nuclear mitochondrial DNA (numtDNA) has been reported within several nuclear genomes. Next to mitochondrial protein-coding genes, numtDNA sequences also encode for mitochondrial tRNA genes. However, the biological roles of numtDNA remain elusive. Results Employing in silico analysis, we identify 281 mitochondrial tRNA homologs in the human genome, which we term nimtRNAs (nuclear intronic mitochondrial-derived tRNAs), being contained within introns of 76 nuclear host genes. Despite base changes in nimtRNAs when compared to their mtRNA homologs, a canonical tRNA cloverleaf structure is maintained. To address potential functions of intronic nimtRNAs, we insert them into introns of constitutive and alternative splicing reporters and demonstrate that nimtRNAs promote pre-mRNA splicing, dependent on the number and positioning of nimtRNA genes and splice site recognition efficiency. A mutational analysis reveals that the nimtRNA cloverleaf structure is required for the observed splicing increase. Utilizing a CRISPR/Cas9 approach, we show that a partial deletion of a single endogenous nimtRNALys within intron 28 of the PPFIBP1 gene decreases inclusion of the downstream-located exon 29 of the PPFIBP1 mRNA. By employing a pull-down approach followed by mass spectrometry, a 3′-splice site-associated protein network is identified, including KHDRBS1, which we show directly interacts with nimtRNATyr by an electrophoretic mobility shift assay. Conclusions We propose that nimtRNAs, along with associated protein factors, can act as a novel class of intronic splicing regulatory elements in the human genome by participating in the regulation of splicing.

scholarly journals Mutational analysis of mitochondrial tRNA genes in patients with lung cancer

2016 ◽  
Vol 19 (2) ◽  
pp. 45-50 ◽  
Author(s):  
ZF He ◽  
LC Zheng ◽  
DY Xie ◽  
SS Yu ◽  
J Zhao
Keyword(s):  
Lung Cancer ◽  
Hot Spots ◽  
Healthy Subjects ◽  
Mutational Analysis ◽  
State Level ◽  
Trna Genes ◽  
Steady State Level ◽  
Mitochondrial Trna ◽  
Blood Samples ◽  
Mitochondrial Trna Genes

AbstractMutations in mitochondrial tRNA (mt-tRNA) genes have been found to be associated with various diseases including lung cancer. To understand the possible relationship between mtRNA mutations and lung cancer, we sequenced the 22 mt-tRNA genes from 200 lung cancer blood samples, as well as 100 healthy subjects. As a result, five mutations were identified including the tRNAAla T5655C, tRNAArg T10454C, tRNALeu(CUN) A12330G, tRNASer(UCN) T7505C and tRNAThr G15927A. These mutations were absent in the healthy subjects. These mutations and polymorphisms were localized at the highly conserved nucleotides of the corresponding mitochondrial tRNAs, which are critical for the tRNA steady state level and may result in failure in the tRNA metabolism. Moreover, through the application of the pathogenicity scoring system, we found that only the T10454C mutation should be classified as a “neutral polymorphism,” while the other mutations were regarded as “definitely pathogenic.” Taken together, our data indicate that tRNA genes are the hot-spots for pathogenic mutations associated with lung cancer. Our findings may provide valuable information for pathophysiology, management and genetic counseling of lung cancer.

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