PNPase knockout results in mtDNA loss and an altered metabolic gene expression program
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PROVIDER: PRJNA437833 | ENA |
REPOSITORIES: ENA
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Project description:Polynucleotide phosphorylase (PNPase) is an essential mitochondria-localized exoribonuclease implicated in multiple biological processes and several human disorders. To reveal role(s) for PNPase in mitochondria, we established PNPase knockout (PKO) systems by first shifting culture conditions to enable cell growth with defective respiration. PKO resulted in loss of mitochondrial DNA (mtDNA) and a transcriptional profile similar to rho0 mtDNA deleted cells, with perturbations in cholesterol, lipid, and secondary alcohol metabolic pathways. PKO cells also showed growth and cell cycle profiles similar to rho0 cells. PKO in mouse inner ear hair cells cause progressive hearing loss that parallel human familial hearing loss previously linked to mutations in PNPase. Combined, our data suggest that mtDNA maintenance could provide a unifying connection for the large number of biological activities reported for PNPase.
2018-05-01 | GSE111668 | GEO
Project description: Not available
| S-EPMC6053217 | biostudies-literature
Project description:Mitochondria are vital due to their principal role in energy production via oxidative phosphorylation (OXPHOS)1. Mitochondria carry their own genome (mtDNA) encoding critical genes involved in OXPHOS, therefore, mtDNA mutations cause fatal or severely debilitating disorders with limited treatment options. 2. Clinical manifestations of mtDNA disease vary based on mutation type and heteroplasmy levels i.e. presence of mutant and normal mtDNA within each cell. 3,4. We evaluated therapeutic concepts of generating genetically corrected pluripotent stem cells for patients with mtDNA mutations. We initially generated multiple iPS cell lines from a patient with mitochondrial encephalomyopathy and stroke-like episodes (MELAS) caused by a heteroplasmic 3243A>G mutation and a patient with Leigh disease carrying a homoplasmic 8993T>G mutation (Leigh-iPS). Due to spontaneous mtDNA segregation in proliferating fibroblasts, isogenic MELAS iPS cell lines were recovered containing exclusively wild type (wt) mtDNA with normal metabolic function. As expected, all iPS cells from the patient with Leigh disease were affected. Using somatic cell nuclear transfer (SCNT; Leigh-NT1), we then simultaneously replaced mutated mtDNA and generated pluripotent stem cells from the Leigh patient fibroblasts. In addition to reversing to a normal 8993G>T, oocyte derived donor mtDNA (human haplotype D4a) in Leigh-NT1 differed from the original haplotype (F1a) at a additional 47 nucleotide sites. Leigh-NT1 cells displayed normal metabolic function compared to impaired oxygen consumption and ATP production in Leigh-iPS cells or parental fibroblasts (Leigh-fib). We conclude that natural segregation of heteroplasmic mtDNA allows the generation of iPS cells with exclusively wild type mtDNA. Moreover, SCNT offers mitochondrial gene replacement strategy for patients with homoplasmic mtDNA disease.
2015-07-16 | GSE61390 | GEO
Project description:Million Veteran Program (MVP) Summary Results from Omics Studies
| PRJNA486224 | ENA
Project description:Million Veteran Program (MVP) Summary Results from Omics Studies
| PRJNA486225 | ENA
Project description:Accumulating evidences suggest a link between mitochondrial dysfunction and female reproduction decline. To directly and systematically figure out the influence of mitochondrial DNA (mtDNA) mutation on oocyte quality and embryo development, we used an mtDNA mutator mouse model (D257A) that harbors a proofreading-deficient version of PolgA. Here we showed that D257A mice developed a profound reduction of fertility at 19-week of age, and accumulated twofold more increase in the levels of point mutations in oocyte mtDNA. Following ovarian hyper-stimulation, we found oocyte numbers retrieved from WT and D257A mice were comparable until 19 weeks of age, while with a half reduced number of oocyte ovulated in D257A mice thereafter. We further found the oocyte quality based on mitochondrial distribution, meiotic spindle assembly, chromosomal segregation and ATP content at 19 weeks of age was identical in both group. Meanwhile, the ovulated oocytes can initiate and sustain early embryo development after in vitro fertilization, and reach the blastocyst stage with no obvious defects compared to WTs. Of note, post-implantation developmental defects were observed in D257A embryos, as revealed by fetal growth retardation and decreased ratios of pups delivered. Furthermore, genome-wide methylation analysis revealed global hypomethylation across the genome of D257A oocytes, with a dramatic reduce in genome repetitive-elements, like DNA transposon, LINEs and SINEs regions. In conclusion, our study presents the direct experimental investigation of the effect of mtDNA mutation on oocyte and embryo competence, and demonstrates altered DNA methylation in oocyte may represent a critical mechanism that mediates the phenotypic defects of mtDNA mutation in post-implantation development.
2020-12-31 | GSE147547 | GEO
Project description:High mitochondrial DNA (mtDNA) copy numbers are essential for oogenesis and embryogenesis and correlate with fertility of oocytes and viability of embryos. To understand the pathology and mechanisms associated with low mtDNA copy numbers, we knocked down mitochondrial transcription factor A (Tfam), a regulator of mtDNA replication, during early zebrafish development. Reduction of Tfam using a splice-modifying morpholino (MO) resulted in a 42%±4% decrease in mtDNA copy number in embryos at 4 days post fertilization (4 dpf). Morphant embryos displayed abnormal development of the eye, brain, heart and muscle, as well as a 50%±11% decrease in ATP production. Transcriptome analysis revealed a decrease in protein-encoding transcripts from the heavy strand of the mtDNA. In addition, various RNA translation pathways were increased, indicating an upregulation of nuclear and mitochondria-related translation. The developmental defects observed were supported by a decreased expression of pathways related to eye development and haematopoiesis. The increase in mRNA translation might serve as a compensation mechanism, but appears insufficient during prolonged periods of mtDNA depletion, highlighting the importance of high mtDNA copy numbers for early development in zebrafish.
2020-03-10 | GSE146696 | GEO
Project description:Expression analysis of cells the given amount of time after mtDNA was lost (or Nar1 expression was repressed) compared to pretreatment (or NAR1 being fully expressed). One time course experiment (Cells a given amount of time following mtDNA loss compared to cells with intact mtDNA), with 2 two condition experiments (Cells with the ATP1-111 genotype 27 hours following mtDNA loss compared to the same cells with intact mtDNA, and cells 27 hours following repression of NAR1 comared to cells expressing NAR1). Each data point had 3 biological replicates, and was dye-swapped. One replicate per array.
2010-06-21 | E-GEOD-15302 | biostudies-arrayexpress
Project description:RNAsequencing data from POLG D257A mutant mouse iPS (induced pluripotent stem) cells. These mice accumulate random point mutations in their mitochondrial genome and manifest progeric features. The reprogramming and phenotype of the cells is described in Hämäläinen et al. 2015, Cell reports, mtDNA Mutagenesis Disrupts Pluripotent Stem Cell Function by Altering Redox Signaling. The goal of the study was to analyze altered gene expression profiles between mutant and wt iPS cells to identify altered biological pathways responsible for the stemness and proliferation defects seem in mtDNA mutator stem cells.
2019-09-24 | GSE133259 | GEO
Project description:Mitochondrial DNA (mtDNA) mutations may contribute to aging and age-related disorders. Previously, we created mice expressing a proofreading-deficient version of the mtDNA polymerase gamma (Polg) which accumulate age-related mtDNA mutations and display premature aging. Here we performed microarray gene expression profiling to identify mtDNA mutation-responsive genes in the cochlea of aged mitochondrial mutator mice. Age-related accumulation of mtDNA mutations was associated with transcriptional alternations consistent with reduced inner ear function, mitochondrial dysfunction, neurodegeneration, and reduced cell structural modulation. Hearing assessment and histopathological results confirmed that aged PolgD257A/D257A (D257A) mice exhibited moderate hearing loss and severe cochlear degenerations. Age-related accumulation of mtDNA mutations also resulted in alternations in gene expression consistent with induction of apoptosis, proteolysis, stress response, and reduced DNA repair. TUNEL (Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling) assay confirmed that the cochleae from aged D257A mice showed significantly more TUNEL positive cells compared to wild-type (WT) mice. The levels of cleaved caspase-3 were also found to increase in the cochleae of aged D257A mice. These observations provide evidence that age-related accumulation of mtDNA mutations is associated with apoptotic cell death in aged cochlea. Our results provide the first global view of molecular events associated with mtDNA mutations in postmitotic tissue, and suggest that apoptosis is the major mechanism of mtDNA mediated cell death in the development of age-related hearing disorder. Experiment Overall Design: To determine the effects of age-related accumulation of mtDNA mutations, each WT sample (n = 5) was compared to each D257A sample (n = 5), generating a total of twenty-five pairwise comparisons. Genes with significantly altered expression levels were sorted into gene ontology biological process categories. Experiment Overall Design: Gene expression change was called statistically significant when at least one gene was called present in a group, the P value was < 0.0500, FC was > 1.1, and FDR was > 30.00 for identification of mtDNA mutations-induced genes. Experiment Overall Design: Affymetrix standard spike controls were used in all experiments (eukaryotic hybridization control kit). Quality control measures were not used. No replicates were done. Dye swap was not used.
2008-11-07 | E-GEOD-4866 | biostudies-arrayexpress