Mitochondrial DNA sequencing in samples of Huntington’s disease patients
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ABSTRACT:
PROVIDER: EGAS00001004092 | EGA |
REPOSITORIES: EGA
Similar Datasets
Project description:This dataset contains sequencing data from a large-scale study of mtDNA variations measured, using a sensitive mtDNA-targeted sequencing method called STAMP, in lymphoblast and blood samples of Huntington’s Disease patients.
| EGAD00001005723 | EGA
Project description:Aberrant localization of proteins to mitochondria disturbs mitochondrial function and contributes to the pathogenesis of Huntington’s disease (HD). However, the crucial factors and the molecular mechanisms remain elusive. Here, we found that heat shock transcription factor 1 (HSF1) accumulates in the mitochondria of HD cell cultures, a YAC128 mouse model, and human striatal organoids derived from HD induced pluripotent stem cells (iPSCs). Overexpression of mitochondria-targeting HSF1 (mtHSF1) in the striatum causes neurodegeneration and HD-like behavior. Mechanistically, mtHSF1 facilitates mitochondrial fission by activating dynamin-related protein 1 (Drp1) phosphorylation at S616. Moreover, mtHSF1 suppresses single-stranded DNA binding protein 1 (SSBP1) oligomer formation, which results in mitochondrial DNA (mtDNA) deletion. Suppression of HSF1 mitochondrial localization by DH1, a unique peptide inhibitor, abolishes HSF1-induced mitochondrial abnormalities and ameliorates deficits in an HD animal model and human striatal organoids. Altogether, our findings describe an unsuspected role of HSF1 in contributing to mitochondrial dysfunction, which may provide a promising therapeutic target for HD.
2022-04-13 | GSE198927 | GEO
Project description:Human mitochondrial DNA (mtDNA) variations, particularly the presence of both mutated and wild type mtDNA known as mtDNA heteroplasmies, have garnered increasing attention due to their clinical relevance to numerous diseases. Nonetheless, the absence of a feasible and economical approach has hampered large-scale population studies on mtDNA variations. Here, we present a novel human mtDNA sequencing method called 123-seq, which is based on the 123-multiplex PCR and completed in consecutive three-step biochemical reactions, with experimental validation of its reliability. The entire library construction process takes only about 90 minutes, enabling efficient capture, amplification, and library construction of mtDNA at the bulk genomic DNA level or single-cell level in a streamlined workflow. We then applied our method to assess single-cell mtDNA mutations in a human sample, profiling over 286 T lymphocytes from a 79-year-old female. We discovered that over 90% of cells carried at least one mtDNA mutation with variant allele frequencies (VAFs) exceeding 20%. Furthermore, 83.78% of these mutation sites were enriched in the protein-coding regions of mtDNA. Our findings suggest that mtDNA mutations with functional significance may be widespread in advanced age, indicating a potential link to T cell aging. This emphasizes the need for further investigation into the dynamics of age-related mtDNA mutations at the single-cell level.
2024-06-30 | GSE266764 | GEO
Project description:Huntington's disease (HD) is a neurodegenerative disorder caused by poly-Q expansion in the Huntingtin (HTT) protein. Here, we delineate elevated mutant HTT (mHTT) levels in patient-derived cells including fibroblasts and iPSC derived cortical neurons using a GLP approved HTT assay. HD patients’ fibroblasts and cortical neurons recapitulate aberrant alternative splicing as a molecular fingerprint of HD. Branaplam is a splicing modulator currently tested in a phase II study in HD (NCT05111249). The drug lowers total HTT (tHTT) and mHTT levels in fibroblasts, iPSC, cortical progenitors, and neurons in a dose dependent manner at an IC50 consistently below 10nm without inducing cellular toxicity. Branaplam promotes inclusion of non-annotated novel exons. Amongst, a 115bp frameshift-inducing exon in the HTT transcript in Branaplam treated cells from Ctrl and HD patients leading to a profound reduction of HTT RNA and protein levels. Importantly, Branaplam ameliorates aberrant alternative splicing in HD patients’ fibroblasts and cortical neurons. These findings highlight the applicability of splicing modulators in the treatment of CAG repeat disorders and decipher their molecular effects associated with the pharmacokinetic and -dynamic properties in patient-derived cellular models.
| EGAS00001006289 | EGA
Project description:Exercise is a fundamental component of human health that is associated with greater life expectancy and reduced risk of chronic diseases. While the beneficial effects of endurance exercise on human health are well established, the molecular mechanisms responsible for these observations remain unclear. Endurance exercise reduces the accumulation of mitochondrial DNA (mtDNA) mutations, alleviates multisystem pathology, and increases the lifespan of the mtDNA mutator mouse model of aging, in which the proof-reading capacity of mitochondrial polymerase gamma (POLG1) is deficient. Clearly, exercise recruited a POLG1-independent mtDNA repair pathway to induce these adaptations, a novel finding as POLG1 is canonically considered to be the sole mtDNA repair enzyme. Here we investigate the identity of this pathway, and show that endurance exercise prevents mitochondrial oxidative damage, attenuates telomere erosion, and mitigates cellular senescence and apoptosis in mtDNA mutator mice. Unexpectedly, we observe translocation of tumour suppressor protein p53 to mitochondria in response to endurance exercise that facilitates mtDNA mutation repair. Indeed, endurance exercise failed to prevent mtDNA mutations, induce mitochondrial biogenesis, preserve mitochondrial morphology, reverse sarcopenia, and mitigate premature mortality in mtDNA mutator mice with muscle-specific deletion of p53. Our data establish an exciting new role for p53 in exercise-mediated maintenance of the mtDNA genome, and presents mitochondrially-targeted p53 as a novel therapeutic modality for aging-associated diseases of mitochondrial etiology. Microarray analysis of gene expression from skeletal muscle (quadriceps femoris) from Mus musculus. N=23 samples per treatment were analysed for whole transcriptiome gene expression profile using NimbleGen Arrays. The treatment groups included wild-type C57Bl/6J mice as the control group, then two treatment groups which both contained homozygous knock-in mtDNA mutator mice (PolG; PolgAD257A/D257A). Once group of these heterozygous knock out mice received regular endurance exercise sessions while the other group remained sedentraty for 6 months. The control group specimens were wild-type litter mates to the transgenic knockout mice.
2015-12-11 | E-GEOD-75869 | biostudies-arrayexpress
Project description:Mitochondrial DNA (mtDNA) damage is considered as a possible primary cause of Parkinson’s disease (PD). To explore the issue, mtDNA sequences from whole blood were analyzed in PD patients and controls using a resequencing chip and allelic substitutions were estimated for each nucleotide position (np) along the entire mtDNA sequence. Overall, 58 np showed a different allelic distribution in the two groups; of these, 81% showed an increase of non-reference alleles in PD patients, similar to findings reported in patients with Alzheimer’s disease, albeit in reduced proportion. These results suggest that age-related neurodegenerative diseases could share a mechanism involving mtDNA.
2019-05-21 | GSE113704 | GEO
Project description:Background: Cell free DNA (cfDNA) in plasma has received increasing attention and has been studied in a broad range of clinical conditions implicating inflammation, cancer, and aging. However, few studies have focused on mitochondrial DNA (mtDNA) in the cell free form. This study characterized the size distribution and sequence characteristics of plasma cell free mtDNA (cf mtDNA) in humans.Methods and Results: We optimized DNA isolation and next-generation sequencing library preparation protocols to better retain short DNA fragments from plasma, and applied these optimized methods to plasma samples from patients with sepsis. After massive parallel sequencing, we verified that our methods can retain substantially shorter DNA fragments than the standard isolation method, resulting in an average of 11.5 fold increase in short DNA fragments yield (DNA < 100bp). We report that cf mtDNA in plasma is highly enriched in short-size cfDNA (30 ~ 60 bp), which is much shorter than the value previously reported (~140 bp). Motivated by this unique size distribution, we size-selected short cfDNA fragments from the sequencing library, which further increased the mtDNA recovery rate by an average of 10.4 fold. Using this approach we detected mixtures of different mtDNA sequences, termed heteroplasmy, in plasma from 3 patients. In one patient who previously received bone marrow transplantation, different minor allele frequencies were observed between plasma and white blood cells (WBC) at heteroplasmic mtDNA sites, consistent with mixed-tissue origin for plasma DNA.Conclusion: mtDNA in plasma exists as very short fragments that exhibit mtDNA heteroplasmy distribution differences from that found in a single organ/tissue. This study is the first report of genome wide identification of mtDNA heteroplasmy in human plasma. Our optimized method can be used to investigate the potential utility of cf mtDNA fragments and heteroplasmy as biomarkers in various diseases.
2016-05-07 | GSE81178 | GEO
Project description:This study aimed to evaluate single nucleotide substitutions in mtDNA and analyze their correlation with inflammatory biomarkers in elderly COVID-19 patients. A total of 30 COVID-19 patients and 33 older adult controls (aged over 65 years) were enrolled. mtDNA was extracted from buffy coat samples and sequenced using a chip-based resequencing system (Affymetrix MitoChip v2.0) which detects both homoplasmic and heteroplasmic mtDNA mutations, and allows the assessment of low-level heteroplasmy. Serum concentration of IL-6, IFN-α, TNF-α and IL-10 were determined in patients by a high-sensitivity immunoassay. We found a higher burden of total heteroplasmic mutation in COVID-19 patients compared to controls with a selective increment in ND1 and COIII genes. Low-level heteroplasmy was significantly elevated in COVID-19 patients, especially in genes of the respiratory complex I. Both heteroplasmic mutation burden and low-level heteroplasmy were associated with increased levels of IL-6, TNF-α, and IFN-α.
2024-01-23 | GSE235626 | GEO
Project description:Type 2 diabetes (T2D), one of the most common metabolic diseases, is the result of insulin resistance or impaired insulin secretion by mitochondrial dysfunctions. Mitochondrial DNA (mtDNA) polymorphisms play an important role in physiological and pathological characteristics of T2D, however, their mechanism is poorly understood. To directly identify candidate mtDNA variants associated with T2D at the genome-wide level, we constructed forty libraries from ten patients with T2D and thirty control individuals for deep sequencing. We characterized their mtDNA atlas, and analyzed their single nucleotide polymorphisms (MtSNPs), insertions and deletions (InDels), and screened potential mtDNA mutation sites associated with T2D. We found ten mtDNA polymorphisms at nucleotides 489T > C, 3105AC > A, 3107N > C, 8701A > G, 9540T > C, 10398A > G, 10400C > T, 10873T > C, 12705C > T and 14783T > C that showed a significant difference between patients and control subjects. Therefore, our results characterize mtDNA atlas of patients with T2D, and further demonstrate that mtDNA variants are participated in the pathophysiology of T2D and other diseases. In addition, mtDNA variants may be candidate molecular biomarkers of T2D, and they may be valuable for early diagnosis of T2D in the future.
2022-08-30 | GSE136892 | GEO
Project description:Extremely variable clinic and genetic features characterize Mitochondrial Encephalomyopathy Disorders (MED). Pathogenic mitochondrial DNA (mtDNA) defects can be divided into large-scale rearrangements and single point mutations. Clinical manifestations become evident when a threshold percentage of the total mtDNA is mutated. In some MED, the "mutant load" in an affected tissue is directly related to the severity of the phenotype. However, the clinical phenotype is not simply a direct consequence of the relative abundance of mutated mtDNA. Other factors, such as nuclear background, can contribute to the disease process, resulting in a wide range of phenotypes caused by the same mutation. Using Affymetrix oligonucleotide cDNA microarrays (HG-U133A), we studied the gene expression profile of muscle tissue biopsies obtained from 12 MED patients (4 common 4977-bp deleted mtDNA and 8 A3243G: 4 PEO and 4 MELAS phenotypes) compared with age-matched healthy individuals. Keywords = mtDNA mutation Keywords = muscle biopsy Keywords = human Keywords = mitochondrial disease Keywords: other
2005-01-22 | GSE1462 | GEO