Polymorphisms in mitochondrial DNA genes coding for subunits in complex I differentially control lifespan and ageing-related pathways in mice.
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE114256 | GEO | 2019/12/23
REPOSITORIES: GEO
Similar Datasets
Project description:Background: Mutations of mitochondrial (mt)DNA cause a variety of human diseases and are also implicated in ageing processes. Results: Primary fibroblasts of the conplastic mouse strain C57BL/6J-mtALR/LTJ with a mutation at position nt4738 resulting in a single nucleotide exchange (leucine to methionine) in the mitochondrial NADH dehydrogenase subunit 2 (Nd2) gene of the respiratory chain show higher enzyme activity and ATP production and lower ROS production than control fibroblasts. Furthermore, Nd2-mutant fibroblasts show a higher proliferation rate and a reduction of senescence markers. Transcriptome analysis reveals members of the p38MAPK pathway as being significantly downregulated in Nd2-mutant mice as compared with controls. In line with this, inhibition of p38MAPK with SB203580 enhanced the proliferation and reduced cytokine secretion in senescent Nd2-mutant fibroblasts. Conclusion: Taken together, we report Nd2 as a new mitochondrial gene with age-protective function in mice, and possibly in humans, which interferes with age-related signaling pathways. MouseRef-8 v2.0 Expression BeadChips of 8 samples of skin fibroblasts; 4 samples of fibroblasts from 4 mice of C57BL/6J-mtALR/LtJ (Nd2-mutant) and 4 samples of fibroblasts from 4 mice of C57BL/6J-mtAKR/J (control)
2014-11-22 | E-GEOD-63551 | biostudies-arrayexpress
Project description:Background: Mutations of mitochondrial (mt)DNA cause a variety of human diseases and are also implicated in ageing processes. Results: Primary fibroblasts of the conplastic mouse strain C57BL/6J-mtALR/LTJ with a mutation at position nt4738 resulting in a single nucleotide exchange (leucine to methionine) in the mitochondrial NADH dehydrogenase subunit 2 (Nd2) gene of the respiratory chain show higher enzyme activity and ATP production and lower ROS production than control fibroblasts. Furthermore, Nd2-mutant fibroblasts show a higher proliferation rate and a reduction of senescence markers. Transcriptome analysis reveals members of the p38MAPK pathway as being significantly downregulated in Nd2-mutant mice as compared with controls. In line with this, inhibition of p38MAPK with SB203580 enhanced the proliferation and reduced cytokine secretion in senescent Nd2-mutant fibroblasts. Conclusion: Taken together, we report Nd2 as a new mitochondrial gene with age-protective function in mice, and possibly in humans, which interferes with age-related signaling pathways.
2014-11-22 | GSE63551 | GEO
Project description:In virtually all eukaryotes, the mitochondrial genome (mitochondrial DNA, mtDNA) encodes proteins necessary for oxidative phosphorylation (OXPHOS) and the RNA machinery required for their synthesis inside the mitochondria. Appropriate regulation of mtDNA copy number and expression is essential for ensuring the correct stoichiometric formation of OXPHOS complexes assembled from both nuclear- and mtDNA-encoded subunits. The mechanisms of mtDNA regulation are not completely understood but are essential to organismal viability and lifespan. Here, using multiple approaches, we identify the presence of N6-methylation of adenosine (6mA) on the mtDNA of diverse animal and plant species. Importantly, we also demonstrate that this modification is regulated in C. elegans by the DNA methyltransferase DAMT-1, and DNA demethylase ALKB-1, which localize to mitochondria. Misregulation of mtDNA 6mA through targeted overexpression of these enzymatic activities inappropriately alters mtDNA copy number and transcript levels, impairing OXPHOS function and producing increased oxidative stress, as well as a shortened lifespan. Compounding defects in mtDNA regulation, reductions in mtDNA 6mA methylation promote the propagation of a deleterious mitochondrial genome across generations. Together, these results reveal that mtDNA 6mA is highly conserved among eukaryotes and regulates lifespan by influencing mtDNA copy number, expression, and heritable mutation levels in vivo.
2024-08-11 | GSE272419 | GEO
Project description:Mitochondrial DNA (mtDNA) mutations predominantly cause neurological diseases. Searching for therapeutic strategies is hindered by the absence of viable neural model systems due to the challenges of engineering mtDNA. We demonstrate that neural progenitor cells (NPCs), rapidly obtained from human induced pluripotent stem cells (iPSCs), retain the parental mtDNA profile and exhibit mitochondrial maturation coupled with a metabolic switch away from glycolysis. Altered calcium homeostasis and mitochondrial hyperpolarization, both potential causes of neural impairment, were observed in iPSC-derived NPCs from patients carrying a deleterious homoplasmic mutation in the mitochondrial gene MT-ATP6 (m.9185T>C). Phenotype-based high-content screenings (HCS) with FDA-approved compounds were then carried out, leading to the identification of possible innovative counteracting agents. We propose iPSC-derived NPCs, displaying mild proliferative properties and proper genotype/metabotype, as a bona fide model system for the establishment of personalized phenotypic drug discovery for untreatable mtDNA disorders affecting the nervous system.
2017-12-07 | GSE70071 | GEO
Project description:The mitochondrial genome encodes essential machinery for respiration and metabolic homeostasis but is paradoxically among the most common targets of somatic mutation in the cancer genome, with truncating mutations in respiratory complex I genes being most over-represented1. While mitochondrial DNA (mtDNA) mutations have been associated with both improved and worsened prognoses in several tumour lineages1–3, whether these mutations are drivers or exert any functional effect on tumour biology remains controversial. Here we discovered that complex I-encoding mtDNA mutations are sufficient to remodel the tumour immune landscape and therapeutic resistance to immune checkpoint blockade. Using mtDNA base editing technology4 we engineered recurrent truncating mutations in the mtDNA-encoded complex I gene, Mt-Nd5, into murine models of melanoma. Mechanistically, these mutations promoted utilisation of pyruvate as a terminal electron acceptor and increased glycolytic flux driven by an over-reduced NAD pool and NADH shuttling between GAPDH and MDH1, mediating a Warburg-like metabolic shift. In turn, without modifying tumour growth, this altered cancer cell-intrinsic metabolism reshaped the tumour microenvironment promoting an anti-tumour immune response characterised by loss of resident neutrophils. This subsequently sensitised tumours bearing high mtDNA mutant heteroplasmy to immune checkpoint blockade, with phenocopy of key metabolic changes being sufficient to mediate this effect. Strikingly, patient lesions bearing >50% mtDNA mutation heteroplasmy also demonstrated a >2.5-fold improved response rate to checkpoint inhibitor blockade. Taken together these data nominate mtDNA mutations as functional regulators of cancer metabolism and tumour biology, with potential for therapeutic exploitation and treatment stratification.
2023-11-07 | GSE230677 | GEO
Project description:The mitochondrial genome encodes essential machinery for respiration and metabolic homeostasis but is paradoxically among the most common targets of somatic mutation in the cancer genome, with truncating mutations in respiratory complex I genes being most over-represented1. While mitochondrial DNA (mtDNA) mutations have been associated with both improved and worsened prognoses in several tumour lineages1–3, whether these mutations are drivers or exert any functional effect on tumour biology remains controversial. Here we discovered that complex I-encoding mtDNA mutations are sufficient to remodel the tumour immune landscape and therapeutic resistance to immune checkpoint blockade. Using mtDNA base editing technology4 we engineered recurrent truncating mutations in the mtDNA-encoded complex I gene, Mt-Nd5, into murine models of melanoma. Mechanistically, these mutations promoted utilisation of pyruvate as a terminal electron acceptor and increased glycolytic flux driven by an over-reduced NAD pool and NADH shuttling between GAPDH and MDH1, mediating a Warburg-like metabolic shift. In turn, without modifying tumour growth, this altered cancer cell-intrinsic metabolism reshaped the tumour microenvironment promoting an anti-tumour immune response characterised by loss of resident neutrophils. This subsequently sensitised tumours bearing high mtDNA mutant heteroplasmy to immune checkpoint blockade, with phenocopy of key metabolic changes being sufficient to mediate this effect. Strikingly, patient lesions bearing >50% mtDNA mutation heteroplasmy also demonstrated a >2.5-fold improved response rate to checkpoint inhibitor blockade. Taken together these data nominate mtDNA mutations as functional regulators of cancer metabolism and tumour biology, with potential for therapeutic exploitation and treatment stratification.
2023-11-07 | GSE227467 | GEO
Project description:Mitochondrial DNA (mtDNA) mutations predominantly cause neurological diseases. Searching for therapeutic strategies is hindered by the absence of viable neural model systems due to the challenges of engineering mtDNA. We demonstrate that neural progenitor cells (NPCs), rapidly obtained from human induced pluripotent stem cells (iPSCs), retain the parental mtDNA profile and exhibit mitochondrial maturation coupled with a metabolic switch away from glycolysis. Altered calcium homeostasis and mitochondrial hyperpolarization, both potential causes of neural impairment, were observed in iPSC-derived NPCs from patients carrying a deleterious homoplasmic mutation in the mitochondrial gene MT-ATP6 (m.9185T>C). Phenotype-based high-content screenings (HCS) with FDA-approved compounds were carried out, leading to the identification of possible innovative counteracting agents. We propose iPSC-derived NPCs, displaying mild proliferative properties and proper genotype/metabotype, as a bona fide model system for the establishment of personalized phenotypic drug discovery for untreatable mtDNA disorders affecting the nervous system. Associated GEO accession number: GSE70071.
2017-01-31 | PXD004977 | Pride
Project description:Integrity of mitochondrial DNA (mtDNA), encoding several subunits of the respiratory chain, is essential to maintain mitochondrial fitness. Mitochondria, as a central hub for metabolism, are affected in a wide variety of human diseases but also during normal ageing, where mtDNA integrity is compromised. Mitochondrial quality control mechanisms work at different levels, and mitophagy and its variants are critical to remove dysfunctional mitochondria and mtDNA to maintain cellular homeostasis. Understanding the mechanisms governing a selective turnover of mutation-bearing mtDNA without affecting the entire mitochondrial pool is fundamental to design therapeutic strategies against mtDNA diseases and ageing. Here, we show that mtDNA damage after expressing a dominant negative version of the mitochondrial helicase Twinkle, or by chemical means, leads to an exacerbated mtDNA turnover. mtDNA removal depends on lysosomal function and requires the autophagy protein Atg5 but is independent of canonical mitophagy or autophagy. Using proximity labelling, we demonstrated that the area of influence of mitochondrial nucleoids differs upon mtDNA damage, which induces mitochondrial membrane remodelling and endosomal recruitment in close proximity to mitochondrial nucleoid sub compartments. Targeting of nucleoids is controlled by the mitochondrial transmembrane proteins ATAD3 and SAMM50, which together with the endosomal trafficking protein VPS35, orchestrate endosomal nucleoid engulfment. SAMM50 acts as a gatekeeper to avoid mtDNA release to the cytoplasm and facilitating mtDNA transfer to VPS35. Lastly, we show that stimulation of lysosomal activity by rapamycin selectively removes mtDNA deletions in vivo, without affecting mtDNA copy number. With these results, we unveil the molecular players of a new complex mechanism specifically targeting and removing mutant mtDNA which occurs outside the mitochondrial network, a process with multiple potential benefits to understand human mtDNA related diseases, either inherited, acquired or due to normal ageing.
2022-11-07 | PXD023939 | Pride
Project description:Mitochondrial DNA (mtDNA) mutations predominantly cause neurological diseases. Searching for therapeutic strategies is hindered by the absence of viable neural model systems due to the challenges of engineering mtDNA. We demonstrate that neural progenitor cells (NPCs), rapidly obtained from human induced pluripotent stem cells (iPSCs), retain the parental mtDNA profile and exhibit mitochondrial maturation coupled with a metabolic switch away from glycolysis. Altered calcium homeostasis and mitochondrial hyperpolarization, both potential causes of neural impairment, were observed in iPSC-derived NPCs from patients carrying a deleterious homoplasmic mutation in the mitochondrial gene MT-ATP6 (m.9185T>C). Phenotype-based high-content screenings (HCS) with FDA-approved compounds were carried out, leading to the identification of possible innovative counteracting agents. We propose iPSC-derived NPCs, displaying mild proliferative properties and proper genotype/metabotype, as a bona fide model system for the establishment of personalized phenotypic drug discovery for untreatable mtDNA disorders affecting the nervous system. Associated GEO accession number: GSE70071.
2017-03-31 | MSV000080849 | MassIVE
Project description:Mitochondrial DNA (mtDNA) encodes essential machinery for respiration and metabolic homeostasis but is paradoxically among the most common targets of somatic mutations in the cancer genome, with truncating mutations in complex I genes being over-represented1 . While mtDNA mutations have been associated with both improved and worsened prognoses in several cancer lineages1–3, whether these mutations are drivers, or exert any functional effect on tumour biology remains controversial. Here we discover that complex I-encoding mtDNA mutations are sufficient to remodel the tumour immune landscape and therapeutic resistance to immune checkpoint blockade. Using mtDNA base editing technology we engineered recurrent truncating mutations in the mtDNA-encoded complex I gene, Mt-Nd5, into murine models of melanoma. Mechanistically, these mutations promoted utilisation of pyruvate as a terminal electron acceptor and increased glycolytic flux driven by an over-reduced NAD pool and NADH shuttling between GAPDH and MDH1, mediating a Warburg-like metabolic shift. In turn, without modifying tumour growth, this altered cancer cell-intrinsic metabolism reshaped the tumour microenvironment of mouse and human cancer in a mutation load-dependent fashion, encouraging an anti-tumour immune response. This subsequently sensitises both mouse and human cancers with high mtDNA mutant heteroplasmy to immune checkpoint blockade. Strikingly, patient lesions bearing >50% mtDNA mutation load demonstrated a >2.5-fold improved response rate to checkpoint inhibitor blockade. Taken together these data nominate mtDNA mutations as functional regulators of cancer metabolism and tumour biology, with potential for therapeutic exploitation and treatment stratification.
2023-11-08 | PXD044987 | Pride