scholarly journals Mitochondrial DNA variation modulates alveolar development in newborn mice exposed to hyperoxia

2019 ◽  
Vol 317 (6) ◽  
pp. L740-L747 ◽  
Author(s):  
Jegen Kandasamy ◽  
Gabriel Rezonzew ◽  
Tamas Jilling ◽  
Scott Ballinger ◽  
Namasivayam Ambalavanan
Keyword(s):  
Mitochondrial Dna ◽  
Stress Responses ◽  
Nuclear Dna ◽  
Oxidant Stress ◽  
Maximal Oxygen Consumption ◽  
Lung Mechanics ◽  
Mouse Lung ◽  
Wild Type ◽  
Newborn Mice ◽  
Alveolar Development

Hyperoxia-induced oxidant stress contributes to the pathogenesis of bronchopulmonary dysplasia (BPD) in preterm infants. Mitochondrial functional differences due to mitochondrial DNA (mtDNA) variations are important modifiers of oxidant stress responses. The objective of this study was to determine whether mtDNA variation independently modifies lung development and mechanical dysfunction in newborn mice exposed to hyperoxia. Newborn C57BL6 wild type (C57n/C57mt, C57WT) and C3H/HeN wild type (C3Hn/C3Hmt, C3HWT) mice and novel Mitochondrial-nuclear eXchange (MNX) strains with nuclear DNA (nDNA) from their parent strain and mtDNA from the other—C57MNX (C57n/C3Hmt) and C3HMNX (C3Hn/C57mt)—were exposed to 21% or 85% O2 from birth to postnatal day 14 (P14). Lung mechanics and histopathology were examined on P15. Neonatal mouse lung fibroblast (NMLF) bioenergetics and mitochondrial superoxide (O2−) generation were measured. Pulmonary resistance and mitochondrial O2− generation were increased while alveolarization, compliance, and NMLF basal and maximal oxygen consumption rate were decreased in hyperoxia-exposed C57WT mice (C57n/C57mt) versus C57MNX mice (C57n/C3Hmt) and in hyperoxia-exposed C3HMNX mice (C3Hn/C57mt) versus C3HWT (C3Hn/C3Hmt) mice. Our study suggests that neonatal C57 mtDNA-carrying strains have increased hyperoxia-induced hypoalveolarization, pulmonary mechanical dysfunction, and mitochondrial bioenergetic and redox dysfunction versus C3H mtDNA strains. Therefore, mtDNA haplogroup variation-induced differences in mitochondrial function could modify neonatal alveolar development and BPD susceptibility.

Abstract 80: Accumulation of Mitochondrial DNA in Autolysosome Causes Inflammation and Heart Failure Through Toll-Like Receptor 9 (TLR9) Signaling

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Takafumi Oka ◽  
Osamu Yamaguchi ◽  
Issei Komuro ◽  
Kinya Otsu
Keyword(s):  
Heart Failure ◽  
Mitochondrial Dna ◽  
Nuclear Dna ◽  
Apoptotic Cell ◽  
Pressure Overload ◽  
Wild Type ◽  
Dnase Ii ◽  
Cardiac Phenotype ◽  
Deficient Mice ◽  
Tlr9 Signaling

Backgrounds Nuclear DNA in apoptotic cell is digested by lysosomal deoxyribonuclease II (DNase II) in macrophages. Improper DNA digestion can lead to inflammation. We previously reported that cardiac-specific DNase II-deficient mice (CKO) exhibited heart failure after transverse aortic constriction (TAC). We observed inflammatory response and DNA accumulation in autolysosome in TAC-operated CKO heart. They were considered to be mitochondrial DNA (mtDNA). In present study, we elucidated the mechanism of inflammation integrated by DNA accumulation in TAC-operated CKO hearts. Furthermore we investigated the pathogenesis of inflammation and heart failure in wild-typeTAC-operated mice. Methods & Results First, we identified the origin of accumulated DNA in lysosome. To label cardiac mtDNA, EdU (5-ethynyl 2’ deoxyuridine) were injected into mice before TAC. In TAC-operated CKO mice, EdU- and LAMP2a (lysosomal marker) or LC3 (autophagosome marker) positive deposits were observed, indicating that mtDNA accumulated in autolysosome. Then, we examined the mechanism how the mtDNA accumulation leads to inflammation. mtDNA has similarities to bacterial DNA, which contains inflammatogenic unmethylated CpG motif. TLR9, localized in the endolysosome, senses DNA with unmethylated CpG motifs. Therefore, we hypothesized that undigested mtDNA is sensed by TLR9. We administrated the inhibitory oligodeoxynucleotides against TLR9 to TAC-operated CKO mice. They attenuated the development of cardiomyopathy in CKO mice. Ablation of Tlr9 also canceled the cardiac phenotype of CKO mice. Next, we examined the involvement of DNA accumulation and TLR9 signaling in wild-type TAC-operated mice. DNase II activity was up-regulated in hypertrophied hearts, but not in failing hearts. LAMP2a- or LC3- positive DNA accumulation was observed in failing hearts. To determine the significance of TLR9 signaling pathway in the pathogenesis of heart failure, we subjected TLR9-deficient mice to TAC. They showed significant resistance to pressure-overload. TLR9-inhibitory oligodeoxynucleotides also improved the mortality in wild-type TAC-operated mice. Conclusion mtDNA-TLR9 axis is involved in inflammation in failing hearts in response to pressure overload.

Reduced amount of mitochondrial DNA in aged human muscle

2003 ◽  
Vol 94 (4) ◽  
pp. 1479-1484 ◽  
Author(s):  
Stephen Welle ◽  
Kirti Bhatt ◽  
Bharati Shah ◽  
Nancy Needler ◽  
Joseph M. Delehanty ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Nuclear Dna ◽  
Maximal Oxygen Consumption ◽  
28S Rrna ◽  
Activity Levels ◽  
Nuclear Respiratory Factor ◽  
Mitochondrial Transcription Factor ◽  
Nuclear Respiratory Factor 1 ◽  
Mtdna Replication ◽  
Cox 2

Muscle concentrations of mRNAs encoded by mitochondrial DNA (mtDNA) decline with aging. To determine whether this can be explained by diminished mtDNA levels, we measured the relative concentrations of mtDNA and a representative mtDNA transcript [encoding cytochrome- coxidase, subunit 2 (COX-2)] in muscle of young (21–27 yr) and older subjects (65–75 yr). The amount of COX-2 mRNA (relative to 28S rRNA) was 22% lower ( P = 0.04) in older muscle, and the amount of mtDNA (relative to nuclear DNA) was 38% lower ( P = 0.0002). The average level of mitochondrial transcription factor A (Tfam), a protein essential for mtDNA replication, was similar in younger and older muscle. Tfam mRNA, nuclear respiratory factor-1 mRNA, and several mRNAs encoding proteins required for mtDNA replication were expressed at similar levels in younger and older muscle. The mtDNA concentrations were only weakly related to age-adjusted aerobic fitness (maximal oxygen consumption) and self-reported physical activity levels. We conclude that the lower concentration of mitochondrial mRNAs in older muscle can be explained by a reduced concentration of mtDNA.

scholarly journals Transforming growth factor-β regulates endothelin-1 signaling in the newborn mouse lung during hypoxia exposure

2012 ◽  
Vol 302 (9) ◽  
pp. L857-L865 ◽  
Author(s):  
Nelida Olave ◽  
Teodora Nicola ◽  
Wei Zhang ◽  
Arlene Bulger ◽  
Masheika James ◽  
...  
Keyword(s):  
Growth Factor ◽  
Lung Function ◽  
Vascular Remodeling ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Mouse Lung ◽  
Newborn Mouse ◽  
Newborn Mice ◽  
Endothelin 1 ◽  
Alveolar Development

We have previously shown that inhibition of transforming growth factor-β (TGF-β) signaling attenuates hypoxia-induced inhibition of alveolar development and abnormal pulmonary vascular remodeling in the newborn mice and that endothelin-A receptor (ETAR) antagonists prevent and reverse the vascular remodeling. The current study tested the hypothesis that inhibition of TGF-β signaling attenuates endothelin-1 (ET-1) expression and thereby reduces effects of hypoxia on the newborn lung. C57BL/6 mice were exposed from birth to 2 wk of age to either air or hypoxia (12% O2) while being given either BQ610 (ETAR antagonist), BQ788 (ETBR antagonist), 1D11 (TGF-β neutralizing antibody), or vehicle. Lung function and development and TGF-β and ET-1 synthesis were assessed. Hypoxia inhibited alveolar development, decreased lung compliance, and increased lung resistance. These effects were associated with increased TGF-β synthesis and signaling and increased ET-1 synthesis. BQ610 (but not BQ788) improved lung function, without altering alveolar development or increased TGF-β signaling in hypoxia-exposed animals. Inhibition of TGF-β signaling reduced ET-1 in vivo, which was confirmed in vitro in mouse pulmonary endothelial, fibroblast, and epithelial cells. ETAR blockade improves function but not development of the hypoxic newborn lung. Reduction of ET-1 via inhibition of TGF-β signaling indicates that TGF-β is upstream of ET-1 during hypoxia-induced signaling in the newborn lung.

scholarly journals Iloprost attenuates hyperoxia-mediated impairment of lung development in newborn mice

2018 ◽  
Vol 315 (4) ◽  
pp. L535-L544 ◽  
Author(s):  
Nelida Olave ◽  
Charitharth Vivek Lal ◽  
Brian Halloran ◽  
Vineet Bhandari ◽  
Namasivayam Ambalavanan
Keyword(s):  
Left Ventricle ◽  
Right Ventricle ◽  
Lung Development ◽  
Mouse Lung ◽  
Synthetic Analog ◽  
Newborn Mouse ◽  
Newborn Mice ◽  
Proinflammatory Mediators ◽  
Alveolar Development ◽  
Cox 2

Cyclooxygenase-2 (COX-2/PTGS2) mediates hyperoxia-induced impairment of lung development in newborn animals and is increased in the lungs of human infants with bronchopulmonary dysplasia (BPD). COX-2 catalyzes the production of cytoprotective prostaglandins, such as prostacyclin (PGI2), as well as proinflammatory mediators, such as thromboxane A2. Our objective was to determine whether iloprost, a synthetic analog of PGI2, would attenuate hyperoxia effects in the newborn mouse lung. To test this hypothesis, newborn C57BL/6 mice along with their dams were exposed to normoxia (21% O2) or hyperoxia (85% O2) from 4 to 14 days of age in combination with daily intraperitoneal injections of either iloprost 200 µg·kg−1·day−1, nimesulide (selective COX-2 antagonist) 100 mg·kg−1·day−1, or vehicle. Alveolar development was estimated by radial alveolar counts and mean linear intercepts. Lung function was determined on a flexiVent, and multiple cytokines and myeloperoxidase (MPO) were quantitated in lung homogenates. Lung vascular and microvascular morphometry was performed, and right ventricle/left ventricle ratios were determined. We determined that iloprost (but not nimesulide) administration attenuated hyperoxia-induced inhibition of alveolar development and microvascular density in newborn mice. Iloprost and nimesulide both attenuated hyperoxia-induced, increased lung resistance but did not improve lung compliance that was reduced by hyperoxia. Iloprost and nimesulide reduced hyperoxia-induced increases in MPO and some cytokines (IL-1β and TNF-α) but not others (IL-6 and KC/Gro). There were no changes in pulmonary arterial wall thickness or right ventricle/left ventricle ratios. We conclude that iloprost improves lung development and reduces lung inflammation in a newborn mouse model of BPD.

scholarly journals Tyrosine Mutation in AAV9 Capsid Improves Gene Transfer to the Mouse Lung

2016 ◽  
Vol 39 (2) ◽  
pp. 544-553 ◽  
Author(s):  
Sabrina V. Martini ◽  
Adriana L. Silva ◽  
Debora Ferreira ◽  
Rafael Rabelo ◽  
Felipe M. Ornellas ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Point Mutations ◽  
Lung Mechanics ◽  
Mouse Lung ◽  
Control Group ◽  
Polymorphonuclear Cells ◽  
Wild Type ◽  
Tyrosine Residues

Background/Aims: Adeno-associated virus (AAV) vectors are being increasingly used as the vector of choice for in vivo gene delivery and gene therapy for many pulmonary diseases. Recently, it was shown that phosphorylation of surface-exposed tyrosine residues from AAV capsid targets the viral particles for ubiquitination and proteasome-mediated degradation, and mutations of these tyrosine residues lead to highly efficient vector transduction in vitro and in vivo in different organs. In this study, we evaluated the pulmonary transgene expression efficacy of AAV9 vectors containing point mutations in surface-exposed capsid tyrosine residues. Methods: Eighteen C57BL/6 mice were randomly assigned into three groups: (1) a control group (CTRL) animals underwent intratracheal (i.t.) instillation of saline, (2) the wild-type AAV9 group (WT-AAV9, 1010 vg), and (3) the tyrosine-mutant Y731F AAV9 group (M-AAV9, 1010 vg), which received (i.t.) self-complementary AAV9 vectors containing the DNA sequence of enhanced green fluorescence protein (eGFP). Four weeks after instillation, lung mechanics, morphometry, tissue cellularity, gene expression, inflammatory cytokines, and growth factor expression were analyzed. Results: No significant differences were observed in lung mechanics and morphometry among the experimental groups. However, the number of polymorphonuclear cells was higher in the WT-AAV9 group than in the CTRL and M-AAV9 groups, suggesting that the administration of tyrosine-mutant AAV9 vectors was better tolerated. Tyrosine-mutant AAV9 vectors significantly improved transgene delivery to the lung (30%) compared with their wild-type counterparts, without eliciting an inflammatory response. Conclusion: Our results provide the impetus for further studies to exploit the use of AAV9 vectors as a tool for pulmonary gene therapy.

scholarly journals Mitochondrial DNA integrity may be a determinant of endothelial barrier properties in oxidant-challenged rat lungs

2011 ◽  
Vol 301 (6) ◽  
pp. L892-L898 ◽  
Author(s):  
Joshua M. Chouteau ◽  
Boniface Obiako ◽  
Olena M. Gorodnya ◽  
Viktor M. Pastukh ◽  
Mykhaylo V. Ruchko ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Fusion Proteins ◽  
Nuclear Dna ◽  
Oxidant Stress ◽  
Barrier Properties ◽  
Pharmacological Intervention ◽  
Dna Integrity ◽  
Barrier Dysfunction ◽  
Mtdna Damage ◽  
Rat Lungs

In cultured pulmonary artery endothelial cells and other cell types, overexpression of mt-targeted DNA repair enzymes protects against oxidant-induced mitochondrial DNA (mtDNA) damage and cell death. Whether mtDNA integrity governs functional properties of the endothelium in the intact pulmonary circulation is unknown. Accordingly, the present study used isolated, buffer-perfused rat lungs to determine whether fusion proteins targeting 8-oxoguanine DNA glycosylase 1 (Ogg1) or endonuclease III (Endo III) to mitochondria attenuated mtDNA damage and vascular barrier dysfunction evoked by glucose oxidase (GOX)-generated hydrogen peroxide. We found that both Endo III and Ogg1 fusion proteins accumulated in lung cell mitochondria within 30 min of addition to the perfusion medium. Both constructs prevented GOX-induced increases in the vascular filtration coefficient. Although GOX-induced nuclear DNA damage could not be detected, quantitative Southern blot analysis revealed substantial GOX-induced oxidative mtDNA damage that was prevented by pretreatment with both fusion proteins. The Ogg1 construct also reversed preexisting GOX-induced vascular barrier dysfunction and oxidative mtDNA damage. Collectively, these findings support the ideas that mtDNA is a sentinel molecule governing lung vascular barrier responses to oxidant stress in the intact lung and that the mtDNA repair pathway could be a target for pharmacological intervention in oxidant lung injury.

Intracellular Mosaicism (Nuclear-/Mitochondrial+) for Thymidine Kinase in Mouse L Cells

1972 ◽  
Vol 10 (2) ◽  
pp. 487-493
Author(s):  
D. A. CLAYTON ◽  
R. L. TEPLITZ
Keyword(s):  
Mitochondrial Dna ◽  
Thymidine Kinase ◽  
Base Composition ◽  
Normal Mouse ◽  
Nuclear Dna ◽  
Mitochondrial Morphology ◽  
Wild Type ◽  
Normal Medium ◽  
L Cells ◽  
D Cells

An electron-microscope and ultracentrifuge examination of mitochondria and mitochondrial DNA from Cl-I-d cells has demonstrated that mitochondria possess the enzyme(s) necessary for incorporation of thymidine and its analogues. These cells lack the nuclear thymidine kinase and are routinely grown in high levels of 5-bromodeoxyuridine (Budr) to select against wild-type revertants. When these cells are grown in the presence of 5-bromodeoxyuridine the mitochondrial DNA incorporates the thymidine analogue into both strands of the DNA duplex while the nuclear DNA shows no incorporation. Approximately 13% of the total thymidines of the M-DNA are replaced by 5-bromodeoxyuridine and the DNA exhibits the form expected for normal mouse mitochondrial DNA. If the cells are grown in normal medium the mitochondrial DNA regains its normal base composition. Comparison of mitochondrial morphology under these 2 conditions reveals that the presence of 5-bromodeoxyuridine results in a distortion of the cristae similar to the effect induced by chloramphenicol. It is hypothesized that the incorporated mutagen (5-bromodeoxyuridine) may be altering the protein products of mitochondrial DNA. The results suggest (1) the existence of a separate and distinct thymidine kinase in the mitochondria of mouse L cells and (2) mutagenic but reversible effects of Budr incorporated into mitochondrial DNA.

scholarly journals Asbestos induces mitochondrial DNA damage and dysfunction linked to the development of apoptosis

2003 ◽  
Vol 285 (5) ◽  
pp. L1018-L1025 ◽  
Author(s):  
Arti Shukla ◽  
Michael Jung ◽  
Maria Stern ◽  
Naomi K. Fukagawa ◽  
Douglas J. Taatjes ◽  
...  
Keyword(s):  
Dna Damage ◽  
Mitochondrial Dna ◽  
Cell Injury ◽  
Nuclear Dna ◽  
Oxidant Stress ◽  
Mesothelial Cells ◽  
Confocal Scanning Laser Microscopy ◽  
Mrna Levels ◽  
Mitochondrial Dna Damage ◽  
Induced Apoptosis

To test the hypothesis that asbestos-mediated cell injury is mediated through an oxidant-dependent mitochondrial pathway, isolated mesothelial cells were examined for mitochondrial DNA damage as determined by quantitative PCR. Mitochondrial DNA damage occurred at fourfold lower concentrations of crocidolite asbestos compared with concentrations required for nuclear DNA damage. DNA damage by asbestos was preceded by oxidant stress as shown by confocal scanning laser microscopy using MitoTracker Green FM and the oxidant probe Redox Sensor Red CC-1. These events were associated with dose-related decreases in steady-state mRNA levels of cytochrome c oxidase, subunit 3 (COIII), and NADH dehydrogenase 5. Subsequently, dose-dependent decreases in formazan production, an indication of mitochondrial dysfunction, increased mRNA expression of pro- and antiapoptotic genes, and increased numbers of apoptotic cells were observed in asbestos-exposed mesothelial cells. The possible contribution of mitochondrial-derived pathways to asbestos-induced apoptosis was confirmed by its significant reduction after pretreatment of cells with a caspase-9 inhibitor. Apoptosis was decreased in the presence of catalase. Last, use of HeLa cells transfected with a mitochondrial transport sequence targeting the human DNA repair enzyme 8-oxoguanine DNA glycosylase to mitochondria demonstrated that asbestos-induced apoptosis was ameliorated with increased cell survival. Studies collectively indicate that mitochondria are initial targets of asbestos-induced DNA damage and apoptosis via an oxidant-related mechanism.

scholarly journals Maternal imprinting, mitochondrial DNA, nuclear DNA and Alzheimer’s disease

2021 ◽  
Vol 1 (2) ◽  
pp. 121-126
Author(s):  
Alberto Pérez-Mediavilla ◽  
Marta Zamarbide
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mitochondrial Dna ◽  
Animal Models ◽  
Nuclear Dna ◽  
Transgenic Animals ◽  
Mitochondrial Proteins ◽  
Wild Type ◽  
Early Onset Alzheimer’S Disease ◽  
Maternal Imprinting

Familial early-onset Alzheimer’s disease (AD) is more probable in individuals coming from mothers diagnosed with AD than from fathers diagnosed with AD. Studies in animal models have shown maternal imprinting due to the transmission to the embryo of altered material in the ovum. In the case of transgenic animals harboring a mutated form of the human amyloid precursor protein (APP), offspring from crosses with wild-type (WT) fathers and transgenic mothers display more abnormalities than offspring from crosses with transgenic fathers and WT mothers. Expression of the mutated APP in the ovum may lead to alterations that may be genetic and/or epigenetic in the nuclear and/or the mitochondrial DNA. These modifications that are transmitted to the new living beings affect more mitochondrial proteins and, therefore, the mitochondrial function may be affected in adulthood by trends present in the ovum.

scholarly journals InsP7is a small-molecule regulator of NUDT3-mediated mRNA decapping and processing-body dynamics

2020 ◽  
Vol 117 (32) ◽  
pp. 19245-19253 ◽  
Author(s):  
Soumyadip Sahu ◽  
Zhenzhen Wang ◽  
Xinfu Jiao ◽  
Chunfang Gu ◽  
Nikolaus Jork ◽  
...  
Keyword(s):  
Stress Responses ◽  
Messenger Rna ◽  
Control Process ◽  
Stem Cell Differentiation ◽  
Wild Type ◽  
Inositol Pyrophosphate ◽  
Body Dynamics ◽  
Processing Body ◽  
The Stability

Regulation of enzymatic 5′ decapping of messenger RNA (mRNA), which normally commits transcripts to their destruction, has the capacity to dynamically reshape the transcriptome. For example, protection from 5′ decapping promotes accumulation of mRNAs into processing (P) bodies—membraneless, biomolecular condensates. Such compartmentalization of mRNAs temporarily removes them from the translatable pool; these repressed transcripts are stabilized and stored until P-body dissolution permits transcript reentry into the cytosol. Here, we describe regulation of mRNA stability and P-body dynamics by the inositol pyrophosphate signaling molecule 5-InsP7(5-diphosphoinositol pentakisphosphate). First, we demonstrate 5-InsP7inhibits decapping by recombinant NUDT3 (Nudix [nucleoside diphosphate linked moiety X]-type hydrolase 3) in vitro. Next, in intact HEK293 and HCT116 cells, we monitored the stability of a cadre of NUDT3 mRNA substrates following CRISPR-Cas9 knockout ofPPIP5Ks(diphosphoinositol pentakisphosphate 5-kinases type 1 and 2, i.e.,PPIP5KKO), which elevates cellular 5-InsP7levels by two- to threefold (i.e., within the physiological rheostatic range). ThePPIP5KKO cells exhibited elevated levels of NUDT3 mRNA substrates and increased P-body abundance. Pharmacological and genetic attenuation of 5-InsP7synthesis in the KO background reverted both NUDT3 mRNA substrate levels and P-body counts to those of wild-type cells. Furthermore, liposomal delivery of a metabolically resistant 5-InsP7analog into wild-type cells elevated levels of NUDT3 mRNA substrates and raised P-body abundance. In the context that cellular 5-InsP7levels normally fluctuate in response to changes in the bioenergetic environment, regulation of mRNA structure by this inositol pyrophosphate represents an epitranscriptomic control process. The associated impact on P-body dynamics has relevance to regulation of stem cell differentiation, stress responses, and, potentially, amelioration of neurodegenerative diseases and aging.

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