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1.
J Enzyme Inhib Med Chem ; 35(1): 129-137, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31694426

RESUMO

The 3-hydroxy-3-methylglutaryl-CoA reductase, a key enzyme of the mevalonate pathway for the synthesis of cholesterol in mammals (ergosterol in fungi), is inhibited by statins, a class of cholesterol lowering drugs. Indeed, statins are in a wide medical use, yet statins treatment could induce side effects as hepatotoxicity and myopathy in patients. We used Saccharomyces cerevisiae as a model to investigate the effects of statins on mitochondria. We demonstrate that statins are active in S.cerevisiae by lowering the ergosterol content in cells and interfering with the attachment of mitochondrial DNA to the inner mitochondrial membrane. Experiments on murine myoblasts confirmed these results in mammals. We propose that the instability of mitochondrial DNA is an early indirect target of statins.


Assuntos
DNA Mitocondrial/metabolismo , Inibidores de Hidroximetilglutaril-CoA Redutases/metabolismo , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Saccharomyces cerevisiae/química , DNA Mitocondrial/química , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/química , Membranas Mitocondriais/química
2.
Enzymes ; 45: 257-287, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31627879

RESUMO

The mitochondrial genome encodes proteins essential for the oxidative phosphorylation and, consequently, for proper mitochondrial function. Its localization and, possibly, structural organization contribute to higher DNA damage accumulation, when compared to the nuclear genome. In addition, the mitochondrial genome mutates at rates several times higher than the nuclear, although the causal relationship between these events are not clearly established. Maintaining mitochondrial DNA stability is critical for cellular function and organismal fitness, and several pathways contribute to that, including damage tolerance and bypass, degradation of damaged genomes and DNA repair. Despite initial evidence suggesting that mitochondria lack DNA repair activities, most DNA repair pathways have been at least partially characterized in mitochondria from several model organisms, including humans. In this chapter, we review what is currently known about how the main DNA repair pathways operate in mitochondria and contribute to mitochondrial DNA stability, with focus on the enzymology of mitochondrial DNA repair.


Assuntos
Dano ao DNA , Reparo do DNA , DNA Mitocondrial/metabolismo , Mitocôndrias/genética , Humanos
3.
Enzymes ; 45: 311-341, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31627882

RESUMO

Mitochondria play a central role in bioenergetics, and fulfill a plethora of functions in cell signaling, programmed cell death, and biosynthesis of key protein cofactors. Mitochondria harbor their own genomic DNA, which encodes protein subunits of the electron transport chain and a full set of transfer and ribosomal RNAs. Mitochondrial DNA (mtDNA) is essential for cellular and organismal functions, and defects in mitochondrial genome maintenance have been implicated in common human diseases and mitochondrial disorders. mtDNA repair and degradation are known pathways to cope with mtDNA damage; however, molecular factors involved in this process have remained unclear. Such knowledge is fundamental to the understanding of mitochondrial genomic maintenance and pathology, because mtDNA degradation may contribute to the etiology of mtDNA depletion syndromes and to the activation of the innate immune response by fragmented mtDNA. This article reviews the current literature regarding the importance of mitochondrial DNA degradation in mtDNA maintenance and stress response, and the recent progress in uncovering molecular factors involved in mtDNA degradation. These factors include key components of the mtDNA replication machinery, such as DNA polymerase γ, helicase Twinkle, and exonuclease MGME1, as well as a major DNA-packaging protein, mitochondrial transcription factor A (TFAM).


Assuntos
DNA Mitocondrial/metabolismo , Genoma Mitocondrial/genética , Estresse Fisiológico , Replicação do DNA , Humanos , Doenças Mitocondriais/genética , Doenças Mitocondriais/patologia
4.
Biochemistry (Mosc) ; 84(8): 884-895, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31522670

RESUMO

DNA replication in human mitochondria has been studied for several decades; however, its mechanism still remains unclear. During the last 15 years, many new experimental data on the mitochondrial replication have appeared, although extremely contradictory. Two asynchronous (strand displacement and RITOLS) and one synchronous (strand-coupled) replication models have been proposed. In the asynchronous models, replication from the origin in the H-chain starts earlier, so that the replication of the two chains ends at different times. The synchronous model is more traditional and implies two replication forks with leading and lagging strands initiated at the same origin. For each of the three models, both confirming and contradicting experimental data exist. Most likely, there is no single model of mitochondrial replication. It is possible that the unique mitochondrial replication machinery that has originated as a results of endosymbiosis has an unexpected variety of replication strategies to maintain the mitochondrial genome. An unusual combination of enzymes of different origin (phage, bacterial, eukaryotic) and unique features of the mitochondrial genome (existance of heavy and light chains, insertions of ribonucleotides, a variety of origins) can allow replication through different mechanisms. In human mitochondria, asynchronous replication seems to dominate; however, synchronous replication is also possible under certain conditions. In the human heart mitochondria, circular mitochondrial DNA (mtDNA) molecules can rearrange in a network of rapidly replicating linear genomes, thereby suggesting possible existence of a wide range of replication mechanisms in the mitochondria. The review describes the main stages of mtDNA replication and enzymes involved in this process, as well as discusses the prospects of mitochondrial replication studies.


Assuntos
Replicação do DNA , DNA Mitocondrial/química , DNA Mitocondrial/metabolismo , Proteínas de Ligação a DNA/metabolismo , Genoma Mitocondrial , Humanos , Mitocôndrias Cardíacas/metabolismo , Proteínas Mitocondriais/metabolismo , Sequências Reguladoras de Ácido Nucleico , Origem de Replicação , Fatores de Transcrição/metabolismo
5.
Biochemistry (Mosc) ; 84(7): 817-828, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31509731

RESUMO

Natural competence of mitochondria for DNA uptake has been known for the last 20 years. Until the present time, all studies of this process have been conducted exclusively in isolated mitochondria, as no system for investigation of the DNA transport into the mitochondria in intact cells has been available. The objective of this work was to improve and standardize the existing approaches for investigating DNA import into plant mitochondria in an in organello system. A method for detecting the import of fluorescently labeled DNA substrates has been developed. Based on the features of DNA import into the mitochondria, we suggested an efficient method for the evaluation of the DNA import efficiency by quantitative PCR. We also developed and characterized the in vivo system that allows to detect DNA transport from the cytoplasm to the mitochondrial matrix in Arabidopsis thaliana protoplasts. A combination of the proposed techniques for studying the DNA uptake by plant mitochondria might be useful for elucidating whether the properties of the mitochondrial DNA import established in the in organello system are preserved in vivo.


Assuntos
Arabidopsis/metabolismo , Transporte Biológico/genética , Brassica napus/metabolismo , DNA Mitocondrial/metabolismo , Mitocôndrias/metabolismo , Zea mays/metabolismo , Genoma Mitocondrial , Genoma de Planta , Técnicas In Vitro/métodos , Proteínas Mitocondriais/genética , Células Vegetais/metabolismo , Protoplastos/metabolismo , Reação em Cadeia da Polimerase em Tempo Real/métodos , Coloração e Rotulagem
6.
Int J Mol Sci ; 20(17)2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31484398

RESUMO

Mitochondria are vital cellular organelles involved in a plethora of cellular processes such as energy conversion, calcium homeostasis, heme biogenesis, regulation of apoptosis and ROS reactive oxygen species (ROS) production. Although they are frequently depicted as static bean-shaped structures, our view has markedly changed over the past few decades as many studies have revealed a remarkable dynamicity of mitochondrial shapes and sizes both at the cellular and intra-mitochondrial levels. Aberrant changes in mitochondrial dynamics and cristae structure are associated with ageing and numerous human diseases (e.g., cancer, diabetes, various neurodegenerative diseases, types of neuro- and myopathies). Another unique feature of mitochondria is that they harbor their own genome, the mitochondrial DNA (mtDNA). MtDNA exists in several hundreds to thousands of copies per cell and is arranged and packaged in the mitochondrial matrix in structures termed mt-nucleoids. Many human diseases are mechanistically linked to mitochondrial dysfunction and alteration of the number and/or the integrity of mtDNA. In particular, several recent studies identified remarkable and partly unexpected links between mitochondrial structure, fusion and fission dynamics, and mtDNA. In this review, we will provide an overview about these recent insights and aim to clarify how mitochondrial dynamics, cristae ultrastructure and mtDNA structure influence each other and determine mitochondrial functions.


Assuntos
DNA Mitocondrial/metabolismo , Dinâmica Mitocondrial/fisiologia , Apoptose/genética , Apoptose/fisiologia , DNA Mitocondrial/genética , Humanos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Dinâmica Mitocondrial/genética , Membranas Mitocondriais/metabolismo , /fisiologia , Espécies Reativas de Oxigênio/metabolismo
7.
Zygote ; 27(5): 272-278, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31411132

RESUMO

Several studies have proposed that cell-free DNA (cfDNA) is a potential biomarker present in follicular fluid (FF) for oocyte quality. Recently we reported that mitochondria-derived cfDNA (mt-cfDNA) closely reflects the amount of cfDNA in FFs. The present study investigated the mechanism regulating mt-cfDNA secretion from porcine granulosa cells. Oocytes and cumulus cell complexes or granulosa cells (GCs) were cultured in maturation medium for 24 or 48 h respectively. Then, nuclear-derived cell-free DNA (n-cfDNA) or mt-cfDNA contents in the spent medium were examined using real-time polymerase chain reaction. When 10 µM of MG132, a proteasome inhibitor, was added to the culture medium, cellular viability of both COCs and GCs decreased and n-cfDNA significantly increased in the culture medium, whereas mt-cfDNA significantly decreased. Supplementation of the culture medium with GW4869, an inhibitor of intracellular vesicle formation, significantly decreased the mt-cfDNA, whereas no effect was observed on n-cfDNA in the medium of both COCs and GCs. Furthermore, the addition of bafilomycin, an inhibitor of autophagy to the culture medium significantly increased mt-cfDNA in the culture medium. After filtration (0.22 µm) and centrifugation (23,000 g), the mt-cfDNA content of the medium decreased significantly. In conclusion, the proteasomal mitochondrial quality control system is upstream of mt-cfDNA secretion and autophagy plays a role in cellular digestion of mitochondrial DNA in the cytoplasm. It is further suggested that dsDNA is enclosed in certain vesicles or associated with small molecules and secreted into the medium.


Assuntos
Ácidos Nucleicos Livres/metabolismo , DNA Mitocondrial/metabolismo , Células da Granulosa/fisiologia , Compostos de Anilina/farmacologia , Animais , Autofagia/efeitos dos fármacos , Compostos de Benzilideno/farmacologia , Sobrevivência Celular , Ácidos Nucleicos Livres/análise , Ácidos Nucleicos Livres/genética , Células Cultivadas , Meios de Cultura/análise , Células do Cúmulo/citologia , Células do Cúmulo/efeitos dos fármacos , Células do Cúmulo/metabolismo , DNA Mitocondrial/análise , DNA Mitocondrial/genética , Feminino , Líquido Folicular/citologia , Líquido Folicular/fisiologia , Células da Granulosa/metabolismo , Oócitos/fisiologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Suínos
8.
Int J Mol Sci ; 20(14)2019 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-31340436

RESUMO

Status epilepticus may decrease mitochondrial biogenesis, resulting in neuronal cell death occurring in the hippocampus. Sirtuin 1 (SIRT1) functionally interacts with peroxisome proliferator-activated receptors and γ coactivator 1α (PGC-1α), which play a crucial role in the regulation of mitochondrial biogenesis. In Sprague-Dawley rats, kainic acid was microinjected unilaterally into the hippocampal CA3 subfield to induce bilateral seizure activity. SIRT1, PGC-1α, and other key proteins involving mitochondrial biogenesis and the amount of mitochondrial DNA were investigated. SIRT1 antisense oligodeoxynucleotide was used to evaluate the relationship between SIRT1 and mitochondrial biogenesis, as well as the mitochondrial function, oxidative stress, and neuronal cell survival. Increased SIRT1, PGC-1α, and mitochondrial biogenesis machinery were found in the hippocampus following experimental status epilepticus. Downregulation of SIRT1 decreased PGC-1α expression and mitochondrial biogenesis machinery, increased Complex I dysfunction, augmented the level of oxidized proteins, raised activated caspase-3 expression, and promoted neuronal cell damage in the hippocampus. The results suggest that the SIRT1 signaling pathway may play a pivotal role in mitochondrial biogenesis, and could be considered an endogenous neuroprotective mechanism counteracting seizure-induced neuronal cell damage following status epilepticus.


Assuntos
Região CA3 Hipocampal/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Sirtuína 1/genética , Estado Epiléptico/genética , Animais , Região CA3 Hipocampal/metabolismo , Região CA3 Hipocampal/patologia , Caspase 3/genética , Caspase 3/metabolismo , Morte Celular/efeitos dos fármacos , Morte Celular/genética , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , Complexo I de Transporte de Elétrons/genética , Complexo I de Transporte de Elétrons/metabolismo , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Injeções Intraventriculares , Ácido Caínico/administração & dosagem , Masculino , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Neurônios/metabolismo , Neurônios/patologia , Biogênese de Organelas , Estresse Oxidativo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Ratos , Ratos Sprague-Dawley , Transdução de Sinais , Sirtuína 1/antagonistas & inibidores , Sirtuína 1/metabolismo , Estado Epiléptico/induzido quimicamente , Estado Epiléptico/metabolismo , Estado Epiléptico/patologia , Técnicas Estereotáxicas
9.
BMC Biol ; 17(1): 53, 2019 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-31286943

RESUMO

Perturbed mitochondrial bioenergetics constitute a core pillar of cancer-associated metabolic dysfunction. While mitochondrial dysfunction in cancer may result from myriad biochemical causes, a historically neglected source is that of the mitochondrial genome. Recent large-scale sequencing efforts and clinical studies have highlighted the prevalence of mutations in mitochondrial DNA (mtDNA) in human tumours and their potential roles in cancer progression. In this review we discuss the biology of the mitochondrial genome, sources of mtDNA mutations, and experimental evidence of a role for mtDNA mutations in cancer. We also propose a 'metabolic licensing' model for mtDNA mutation-derived dysfunction in cancer initiation and progression.


Assuntos
DNA Mitocondrial/genética , Genoma Mitocondrial/genética , Mutação , Neoplasias/genética , Animais , Carcinogênese/genética , DNA Mitocondrial/metabolismo , Progressão da Doença , Humanos , Camundongos , Neoplasias/metabolismo
10.
Clin Chim Acta ; 496: 93-99, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31271740

RESUMO

BACKGROUND: Mitochondrial DNA depletion syndrome is a group of heterogeneous diseases with non-specific presentation. The common feature is the quantitative depletion of mitochondrial DNA without qualitative defects. Diagnosis of these diseases poses a challenge and whole exome sequencing is often needed for their diagnoses. CASE: Two siblings of a quartet family, presenting with hypotonia, microcephaly and severe intellectual disability, have been diagnosed to harbor two heterozygous variants in trans in the DTYMK gene of the thymidine biosynthesis pathway. Mitochondrial DNA depletion has been demonstrated in silico in the more severe sibling. CONCLUSIONS: We suggest the consideration of incorporating DTYMK as one of the associated genes of mitochondrial DNA depletion syndrome (MDDS). DTYMK may be the missing link in the mitochondrial nucleotide salvage pathway but further characterization and additional evidence would be needed.


Assuntos
DNA Mitocondrial/metabolismo , Doenças Mitocondriais/enzimologia , Doenças Mitocondriais/genética , Núcleosídeo-Fosfato Quinase/genética , Criança , DNA Mitocondrial/genética , Humanos , Lactente , Masculino , Irmãos , Sequenciamento Completo do Exoma
11.
Reprod Biol Endocrinol ; 17(1): 54, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31291946

RESUMO

BACKGROUND: Cell-free mitochondrial DNA (cf-mtDNA) in body fluids has attracted much attention for the purpose of monitoring disease because of the clinical advantages. This study investigated whether the cf-mtDNA content in human follicular fluid samples was associated with oocyte and embryo developmental competence. METHODS: We collected 225 individual follicular fluid samples from 92 patients undergoing conventional in vitro fertilization (n = 53) or intracytoplasmic sperm injection (n = 39). cf-mtDNA and cell-free nuclear DNA (cf-nDNA) were measured using real-time quantitative PCR for the ND1 and ß-globin genes. Multivariate logistic regression and linear regression were used to analyze data. RESULTS: The relative cf-mtDNA content (cf-ND1/cf-ß-globin ratio) in follicular fluid was significantly lower in the group showing blastocyst development than in the non-blastocyst group (P = 0.030). Additionally, the relative cf-mtDNA content was significantly and positively correlated with the age of the female patient (P = 0.009), while the relative cf-mtDNA content for older women (≥38 years old) with anti-Müllerian hormone (AMH) ≤1.1 ng/ml was significantly higher than in those with AMH > 1.1 ng/ml (P <0.05). The cf-nDNA content was significantly positively correlated with the antral follicle count (P = 0.012), and significantly negatively correlated with both the number of days of stimulation and the total dose of gonadotropin administration (P = 0.039 and P = 0.015, respectively). Neither cf-mtDNA nor cf-nDNA levels in follicular fluid were associated with oocyte maturation, fertilization, or Day 3 embryo morphological scoring. CONCLUSIONS: The relative cf-mtDNA content in human follicular fluid was negatively correlated with blastulation and positively correlated with the patient age, indicating that it is a promising bio-marker to evaluate oocyte developmental competence.


Assuntos
Biomarcadores/metabolismo , Blastocisto/metabolismo , Ácidos Nucleicos Livres/metabolismo , DNA Mitocondrial/metabolismo , Líquido Folicular/metabolismo , Técnicas de Reprodução Assistida , Adulto , Blastocisto/citologia , Blastocisto/fisiologia , Ácidos Nucleicos Livres/genética , DNA Mitocondrial/genética , Embrião de Mamíferos/embriologia , Embrião de Mamíferos/metabolismo , Desenvolvimento Embrionário , Feminino , Humanos , Pessoa de Meia-Idade , Oócitos/citologia , Oócitos/crescimento & desenvolvimento , Oócitos/metabolismo , Gravidez , Adulto Jovem
12.
BMC Biotechnol ; 19(1): 42, 2019 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-31253149

RESUMO

BACKGROUND: Artificial Mitochondrial Transfer or Transplant (AMT/T) can be used to reduce the stress and loss of viability of damaged cells. In MitoCeption, a type of AMT/T, the isolated mitochondria and recipient cells are centrifuged together at 4 °C and then co-incubated at 37 °C in normal culture conditions, inducing the transfer. Ultraviolet radiation (UVR) can affect mitochondria and other cell structures, resulting in tissue stress, aging, and immunosuppression. AMT/T could be used to repair UVR cellular and mitochondrial damage. We studied if a mitochondrial mix from different donors (Primary Allogeneic Mitochondrial Mix, PAMM) can repair UVR damage and promote cell survival. RESULTS: Using a simplified adaption of the MitoCeption protocol, we used peripheral blood mononuclear cells (PBMCs) as the recipient cell model of the PAMM in order to determine if this protocol could repair UVR damage. Our results showed that when PBMCs are exposed to UVR, there is a decrease in metabolic activity, mitochondrial mass, and mtDNA sequence stability as well as an increase in p53 expression and the percentage of dead cells. When PAMM MitoCeption was used on UVR-damaged cells, it successfully transferred mitochondria from different donors to distinct PBMCs populations and repaired the observed UVR damage. CONCLUSION: Our results represent an advancement in the applications of MitoCeption and other AMT/T. We showed that PBMCs could be used as a PAMM source of mitochondria. We also showed that these mitochondria can be transferred in a mix from different donors (PAMM) to UVR-damaged, non-adherent primary cells. Additionally, we decreased the duration of the MitoCeption protocol.


Assuntos
Dano ao DNA , Leucócitos Mononucleares/metabolismo , Mitocôndrias/metabolismo , Mitocôndrias/transplante , Raios Ultravioleta , Adulto , Sobrevivência Celular/genética , Células Cultivadas , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , Feminino , Humanos , Leucócitos Mononucleares/efeitos da radiação , Masculino , Mitocôndrias/genética , Espécies Reativas de Oxigênio/metabolismo , Transplante Homólogo/métodos , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo
13.
Int J Radiat Biol ; 95(7): 1043-1049, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31157572

RESUMO

In the 60 years since the inaugural edition of the International Journal of Radiation Biology, much of our understanding of the biological effects of solar radiation has changed. Earlier in the century, sunlight played a 'hero's' role in reducing disabling rickets, while today debate still continues on the amount of sun required before exposure reveals the 'villainous' side of solar radiation. Although knowledge of the ultra violet (UV) component of sunlight as a carcinogen has become widespread, skin cancer rates are still rising yearly. Twentieth century attitudes have seen an about-face in the field of dermatological sun protection, with sunscreens changing from recipes designed to promote a 'healthy tan' to formulations proven to block both ultraviolet B (UVB) and more recently, ultraviolet A (UVA), to minimize premature sun-aging and skin cancer risk. In the early 1960s, DNA was first found to exist within mitochondria, while recently the connections between mitochondrial changes and UV radiation exposure have been expanded. Sixty years ago, understanding of the endocrine systems of mammals was enjoying its infancy. Early discoveries that light, particularly natural light, could have profound effects on functions such as sleep patterns and hormonal balance were made, while today more advanced knowledge has led to lighting improvements having pronounced effects on human wellbeing. Photosensitization 60 years ago was a health concern for both humans and their domestic animals, while today chemically engineered photosensitizing drugs can be administered along with highly directed light to pinpoint delivery targets for drug action. Life on earth is inextricably bound up with solar radiation. This article attempts to outline many of the ways in which our opinions about solar radiation have changed since the journal's inception.


Assuntos
Radiobiologia/história , Luz Solar , Raios Ultravioleta , Animais , DNA/efeitos da radiação , Dano ao DNA , DNA Mitocondrial/metabolismo , História do Século XX , História do Século XXI , Humanos , Saúde Mental , Mitocôndrias/efeitos da radiação , Neoplasias/etiologia , Neoplasias/radioterapia , Fármacos Fotossensibilizantes , Raquitismo/radioterapia , Pele/efeitos da radiação , Envelhecimento da Pele/efeitos da radiação , Neoplasias Cutâneas/etiologia , Neoplasias Cutâneas/radioterapia , Vitamina D/metabolismo
14.
Environ Int ; 129: 470-477, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31158593

RESUMO

BACKGROUND: Prenatal exposure to thallium is related to adverse birth outcomes. However, little is known about the effects of prenatal exposure to thallium on the mitochondrial DNA copy number (mtDNAcn) in newborns; such knowledge might reveal a potential mechanism linking maternal thallium exposure and adverse birth outcomes. OBJECTIVE: To investigate the trimester-specific associations of maternal thallium exposure with cord blood leukocyte mtDNAcn. METHODS: A total of 746 pregnant women with trimester-specific urinary samples and cord blood samples were recruited from Wuhan Children Hospital between November 2013 and March 2015 in Wuhan City, China. The concentration of thallium in maternal urine was quantified using inductively coupled plasma mass spectrometry (ICP-MS). Cord blood leukocyte mtDNAcn was measured by real-time quantitative polymerase chain reaction (qPCR). Trimester-specific associations of specific gravity (SG)-adjusted urinary thallium concentrations with mtDNAcn were estimated using a multiple informant model. RESULTS: The geometric mean value of maternal urinary thallium was 0.34 µg/L, 0.36 µg/L, and 0.34 µg/L for the first, second, and third trimesters, respectively. Prenatal exposure to thallium during the first trimester, rather than during the second or the third trimester, was identified as negatively related to mtDNAcn. The multiple informant model showed a 10.4% lower level of mtDNAcn with each doubling increase of thallium levels (95% CI, -16.4%, -3.9%; P = 0.002). The observed associations were stronger among female newborns and among newborns born to older mothers. CONCLUSIONS: The present study revealed a significant negative association between maternal thallium exposure during early pregnancy and cord blood leukocyte mtDNAcn in Chinese newborns, pointing to the important role of mitochondria as a target of thallium toxicity in early pregnancy.


Assuntos
Variações do Número de Cópias de DNA , DNA Mitocondrial/sangue , DNA Mitocondrial/metabolismo , Exposição Materna , Tálio/toxicidade , Adulto , China , Estudos de Coortes , Feminino , Humanos , Recém-Nascido , Gravidez , Primeiro Trimestre da Gravidez , Terceiro Trimestre da Gravidez , Trimestres da Gravidez
15.
Indian J Tuberc ; 66(2): 227-233, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31151489

RESUMO

BACKGROUND: Pulmonary tuberculosis (PTB) remains a major cause of morbidity and mortality all around the world. Recent studies have pointed out increased oxidative stress and also DNA damage in peripheral blood in PTB. Till date, to the best of our knowledge, no study has so far been conducted to show the mitochondrial DNA (mtDNA) deletions mapping in PTB patients. Therefore we performed the present study with the aim to investigate oxidative stress parameters along with mtDNA damage in newly diagnosed untreated PTB patients. MATERIAL AND METHODS: This is a prospective study carried out in Mahatma Gandhi Institute of Medical Sciences, Sevagram,Wardha, Maharashtra during september 2017 to september 2018.Thirty newly diagnosed untreated PTB patients and thirty age matched healthy controls were enrolled in the present study. Analysis of Oxidative stress parameters such as nitric oxide (NO) and malondialdehyde (MDA) were done by calorimetric methods. Assessment of mitochondrial DNA damage was carried out by mtDNA deletions mapping using primer shift long range polymerase chain reaction technique. RESULTS: There was significant increase in levels of oxidative stress parameters, nitric oxide and malondialdehyde, in PTB patients compared to controls (p < 0.01). Generally there are two common deletion sites of "13 bp direct repeats" (ACCTCCCTCACCA) in mtDNA. One at the junction sites from bp 8470 to 8482 bp and another from bp 13447 to 13460 bp which make mtDNA more prone for 4977bp deletion. Out of thirty cases of PTB, two cases showed mtDNA damage in the form of mtDNA deletion of 4977bp. There was no mtDNA deletion in any control which can be attributed to continuous generation of oxidative stress. CONCLUSION: This pilot study has been able to demonstrate that compared to controls, in newly diagnosed pulmonary tuberculosis patients some mtDNA damage did occur and was probably due to continuous generation of oxidative stress in tuberculous patients. However, sample size is too small to draw any conclusions but definitely a more comprehensive study, by recruiting more number of pulmonary tuberculosis patients is warranted to establish correlation between oxidative stress and mtDNA damage in PTB.


Assuntos
DNA Mitocondrial/metabolismo , Estresse Oxidativo , Tuberculose Pulmonar/metabolismo , Adolescente , Adulto , Estudos de Casos e Controles , Dano ao DNA , DNA Mitocondrial/genética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Estudos Prospectivos , Deleção de Sequência , Tuberculose Pulmonar/genética , Adulto Jovem
16.
Int Rev Neurobiol ; 145: 177-209, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31208524

RESUMO

Survival of human peripheral nervous system neurons and associated distal axons is highly dependent on energy. Diabetes invokes a maladaptation in glucose and lipid energy metabolism in adult sensory neurons, axons and Schwann cells. Mitochondrial (Mt) dysfunction has been implicated as an etiological factor in failure of energy homeostasis that results in a low intrinsic aerobic capacity within the neuron. Over time, this energy failure can lead to neuronal and axonal degeneration and results in increased oxidative injury in the neuron and axon. One of the key pathways that is impaired in diabetic peripheral neuropathy (DPN) is the energy sensing pathway comprising the nicotinamide-adenine dinucleotide (NAD+)-dependent Sirtuin 1 (SIRT1)/peroxisome proliferator-activated receptor-γ coactivator α (PGC-1α)/Mt transcription factor A (TFAM or mtTFA) signaling pathway. Knockout of PGC-1α exacerbates DPN, whereas overexpression of human TFAM is protective. LY379268, a selective metabolomic glutamate receptor 2/3 (mGluR2/3) receptor agonist, also upregulates the SIRT1/PGC-1α/TFAM signaling pathway and prevents DPN through glutamate recycling in Schwann/satellite glial (SG) cells and by improving dorsal root ganglion (DRG) neuronal Mt function. Furthermore, administration of nicotinamide riboside (NR), a precursor of NAD+, prevents and reverses DPN, in part by increasing NAD+ levels and SIRT1 activity. In summary, we review the role of NAD+, mitochondria and the SIRT1-PGC-1α-TFAM pathway both from the perspective of pathogenesis and therapy in DPN.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Neuropatias Diabéticas/metabolismo , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , NAD/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Sirtuína 1/metabolismo , Fatores de Transcrição/metabolismo , Aminoácidos/efeitos dos fármacos , Aminoácidos/farmacologia , Animais , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , DNA Mitocondrial/metabolismo , Humanos , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Transdução de Sinais
17.
Int Rev Neurobiol ; 145: 67-82, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31208527

RESUMO

Mitochondria play an essential role in cellular energy production and calcium homeostasis. Abnormalities in mitochondrial homeostasis and function are seen in several acquired as well as genetic neuropathies, emphasizing their prominent role in neuronal cell activities. Chronic infection with HIV, even when appropriately treated, is a risk factor for developing peripheral neuropathy. In this chapter, we discuss the way in which HIV infection, the resultant toxic viral products that are generated, and some of the viral inhibitors used in its treatment may lead to abnormal mitochondrial function. Of importance are the effects on mitochondrial DNA replication and the neurotoxic effects of the viral gp120 protein. One aspect of mitochondrial dysfunction that remains unexplored is the role of the interaction between mitochondria and the endoplasmic reticulum as a possible target of disruption in HIV neuropathy.


Assuntos
Antivirais/efeitos adversos , Infecções por HIV/genética , Infecções por HIV/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Doenças do Sistema Nervoso Periférico/metabolismo , Animais , Replicação do DNA/efeitos dos fármacos , DNA Mitocondrial/efeitos dos fármacos , DNA Mitocondrial/metabolismo , Proteína gp120 do Envelope de HIV/toxicidade , Infecções por HIV/complicações , Humanos , Modelos Neurológicos , Doenças do Sistema Nervoso Periférico/complicações
18.
Int J Mol Sci ; 20(12)2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-31226795

RESUMO

Mammalian mitochondria contain four topoisomerases encoded in the nuclear genome: TOP1MT, TOP2α, TOP2ß, and TOP3α. They also contain the two known tyrosyl-DNA phosphodiesterases (TDPs): TDP1 and TDP2, including a specific TDP2S isoform. Both TDP1 and TDP2 excise abortive topoisomerase cleavage complexes (TOPccs), yet their molecular structures and mechanisms are different. TDP1 is present across eukaryotes, from yeasts to humans and belongs to the phospholipase D family. It functions without a metal cofactor and has a broad activity range, as it also serves to cleanse blocking 3'-DNA ends bearing phosphoglycolate, deoxyribose phosphate, nucleoside, nucleoside analogs (zidovudine), abasic moieties, and with a lower efficiency, TOP2ccs. Found in higher vertebrates, TDP2 is absent in yeast where TDP1 appears to perform its functions. TDP2 belongs to the exonuclease/endonuclease/phosphodiesterase family and requires magnesium as a cofactor to excise TOP2ccs, and it also excises TOP1ccs, albeit with a lower efficiency. Here, we review TDP1 and TDP2 in the context of mitochondrial DNA repair and discuss potential new research areas centered on the mitochondrial TDPs.


Assuntos
Reparo do DNA , DNA Mitocondrial/genética , Proteínas Nucleares/metabolismo , Diester Fosfórico Hidrolases/metabolismo , Fatores de Transcrição/metabolismo , Animais , Dano ao DNA , DNA Mitocondrial/metabolismo , Humanos , Mitocôndrias/genética , Mitocôndrias/metabolismo
19.
Anim Sci J ; 90(7): 849-856, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31067600

RESUMO

This study evaluated the effects of cryopreservation by slow freezing on the mitochondrial function, DNA integrity, and developmental ability of bovine embryos and examined whether resveratrol treatment of the frozen-thawed blastocysts improved embryonic viability. In vitro produced bovine embryos were subjected to slow freezing. After thawing, the ATP content and mitochondrial DNA integrity (mtDNA), determined by real-time PCR targeting short and long mitochondrial sequences, was found to be lower in frozen-thawed embryos than in fresh embryos, and mtDNA copy number was significantly reduced during the 24-hr incubation post warming. Furthermore, immunostaining against double-strand DNA revealed DNA damage in frozen-thawed embryos. When frozen-thawed embryos were incubated in the medium containing 0.5 µM resveratrol, SIRT1 expression, and survival rate of the embryos significantly improved compared with the vehicle-treated embryos. In addition, cell-free mtDNA content in medium was higher in case of resveratrol-treated embryos than of vehicle-treated embryos. In conclusion, slow freezing affects mitochondrial integrity and function in the blastocysts. In the frozen-thawed embryos, mitochondria were removed during post-thawing incubation and resveratrol enhanced the process, resulting in improved survivability of the embryos.


Assuntos
Blastocisto/fisiologia , Criopreservação/métodos , Desenvolvimento Embrionário/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/fisiologia , Resveratrol/farmacologia , Preservação de Tecido/métodos , Trifosfato de Adenosina/metabolismo , Animais , Bovinos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Variações do Número de Cópias de DNA/efeitos dos fármacos , Dano ao DNA , DNA Mitocondrial/metabolismo , Feminino , Mitocôndrias/genética
20.
Gene ; 706: 172-180, 2019 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-31082499

RESUMO

Molecular mechanisms of aging and longevity are still mostly unknown. Mitochondria play central roles in cellular metabolism and aging. In this study, we identified three deletion mutants of mitochondrial metabolism genes (ppa2∆, dss1∆, and afg3∆) that live longer than wild-type cells. These long-lived cells harbored significantly decreased amount of mitochondrial DNA (mtDNA) and reactive oxygen species (ROS). Compared to the serpentine nature of wild-type mitochondria, a different dynamics and distribution pattern of mitochondria were observed in the mutants. Both young and old long-lived cells produced relatively low but adequate levels of ATP for cellular activities. The status of the retrograde signaling was checked by expression of CIT2 gene and found activated in long-lived mutants. The mutant cells were also profiled for their gene expression patterns, and genes that were differentially regulated were determined. All long-lived cells comprised similar pleiotropic phenotype regarding mitochondrial dynamics and functions. Thus, this study suggests that DSS1, PPA2, and AFG3 genes modulate the lifespan by altering the mitochondrial morphology and functions.


Assuntos
Longevidade/genética , Mitocôndrias/genética , Mitocôndrias/metabolismo , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Envelhecimento , DNA Mitocondrial/metabolismo , Exorribonucleases/genética , Exorribonucleases/metabolismo , Genes Mitocondriais/genética , Genótipo , Proteínas Mitocondriais/genética , Estresse Oxidativo , Fenótipo , Bombas de Próton/genética , Bombas de Próton/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Deleção de Sequência , Transdução de Sinais
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