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Whitcomb LA, Cao X, Thomas D, Wiese C, Pessin AS, Zhang R, Wu JC, Weil MM, Chicco AJ. Mitochondrial reactive oxygen species impact human fibroblast responses to protracted γ-ray exposures. Int J Radiat Biol 2024; 100:890-902. [PMID: 38631047 DOI: 10.1080/09553002.2024.2338518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 03/26/2024] [Indexed: 04/19/2024]
Abstract
Purpose: Continuous exposure to ionizing radiation at a low dose rate poses significant health risks to humans on deep space missions, prompting the need for mechanistic studies to identify countermeasures against its deleterious effects. Mitochondria are a major subcellular locus of radiogenic injury, and may trigger secondary cellular responses through the production of reactive oxygen species (mtROS) with broader biological implications. Methods and Materials: To determine the contribution of mtROS to radiation-induced cellular responses, we investigated the impacts of protracted γ-ray exposures (IR; 1.1 Gy delivered at 0.16 mGy/min continuously over 5 days) on mitochondrial function, gene expression, and the protein secretome of human HCA2-hTERT fibroblasts in the presence and absence of a mitochondria-specific antioxidant mitoTEMPO (MT; 5 µM). Results: IR increased fibroblast mitochondrial oxygen consumption (JO2) and H2O2 release rates (JH2O2) under energized conditions, which corresponded to higher protein expression of NADPH Oxidase (NOX) 1, NOX4, and nuclear DNA-encoded subunits of respiratory chain Complexes I and III, but depleted mtDNA transcripts encoding subunits of the same complexes. This was associated with activation of gene programs related to DNA repair, oxidative stress, and protein ubiquination, all of which were attenuated by MT treatment along with radiation-induced increases in JO2 and JH2O2. IR also increased secreted levels of interleukin-8 and Type I collagens, while decreasing Type VI collagens and enzymes that coordinate assembly and remodeling of the extracellular matrix. MT treatment attenuated many of these effects while augmenting others, revealing complex effects of mtROS in fibroblast responses to IR. Conclusion: These results implicate mtROS production in fibroblast responses to protracted radiation exposure, and suggest potentially protective effects of mitochondrial-targeted antioxidants against radiogenic tissue injury in vivo.
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Affiliation(s)
- Luke A Whitcomb
- Department of Biomedical Sciences, Colorado State University, CO, USA
| | - Xu Cao
- Stanford Cardiovascular Institute, Stanford University, Palo Alto, CA, USA
| | - Dilip Thomas
- Stanford Cardiovascular Institute, Stanford University, Palo Alto, CA, USA
| | - Claudia Wiese
- Department of Environmental and Radiological Health Sciences, Colorado State University, CO, USA
| | - Alissa S Pessin
- Department of Biomedical Sciences, Colorado State University, CO, USA
| | - Robert Zhang
- Department of Biomedical Sciences, Colorado State University, CO, USA
| | - Joseph C Wu
- Stanford Cardiovascular Institute, Stanford University, Palo Alto, CA, USA
| | - Michael M Weil
- Department of Environmental and Radiological Health Sciences, Colorado State University, CO, USA
| | - Adam J Chicco
- Department of Biomedical Sciences, Colorado State University, CO, USA
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Wu YL, Christodoulou AG, Beumer JH, Rigatti LH, Fisher R, Ross M, Watkins S, Cortes DRE, Ruck C, Manzoor S, Wyman SK, Stapleton MC, Goetzman E, Bharathi S, Wipf P, Tan T, Eiseman JL, Christner SM, Guo J, Lo CWY, Epperly MW, Greenberger JS. Mitigation of Fetal Irradiation Injury from Mid-Gestation Total Body Radiation with Mitochondrial-Targeted GS-Nitroxide JP4-039. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.13.580105. [PMID: 38405696 PMCID: PMC10888932 DOI: 10.1101/2024.02.13.580105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Victims of a radiation terrorist event will include pregnant women and unborn fetuses. Mitochondrial dysfunction and oxidative stress are key pathogenic factors of fetal irradiation injury. The goal of this preclinical study is to investigate the efficacy of mitigating fetal irradiation injury by maternal administration of the mitochondrial-targeted gramicidin S (GS)- nitroxide radiation mitigator, JP4-039. Pregnant female C57BL/6NTac mice received 3 Gy total body ionizing irradiation (TBI) at mid-gestation embryonic day 13.5 (E13.5). Using novel time- and-motion-resolved 4D in utero magnetic resonance imaging (4D-uMRI), we found TBI caused extensive injury to the fetal brain that included cerebral hemorrhage, loss of cerebral tissue, and hydrocephalus with excessive accumulation of cerebrospinal fluid (CSF). Histopathology of the fetal mouse brain showed broken cerebral vessels and elevated apoptosis. Further use of novel 4D Oxy-wavelet MRI capable of probing in vivo mitochondrial function in intact brain revealed significant reduction of mitochondrial function in the fetal brain after 3Gy TBI. This was validated by ex vivo Oroboros mitochondrial respirometry. Maternal administration JP4-039 one day after TBI (E14.5), which can pass through the placental barrier, significantly reduced fetal brain radiation injury and improved fetal brain mitochondrial respiration. This also preserved cerebral brain tissue integrity and reduced cerebral hemorrhage and cell death. As JP4-039 administration did not change litter sizes or fetus viability, together these findings indicate JP4-039 can be deployed as a safe and effective mitigator of fetal radiation injury from mid-gestational in utero ionizing radiation exposure. One Sentence Summary Mitochondrial-targeted gramicidin S (GS)-nitroxide JP4-039 is safe and effective radiation mitigator for mid-gestational fetal irradiation injury.
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Abdullaev SA, Evdokimovskii EV, Gaziev AI. A Study of Mitochondrial DNA Copy Number and Heteroplasmy in Different Rat Brain Regions after Cranial Proton Impact. BIOL BULL+ 2021. [DOI: 10.1134/s1062359020110023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Allegra AG, Mannino F, Innao V, Musolino C, Allegra A. Radioprotective Agents and Enhancers Factors. Preventive and Therapeutic Strategies for Oxidative Induced Radiotherapy Damages in Hematological Malignancies. Antioxidants (Basel) 2020; 9:antiox9111116. [PMID: 33198328 PMCID: PMC7696711 DOI: 10.3390/antiox9111116] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/08/2020] [Accepted: 11/10/2020] [Indexed: 12/13/2022] Open
Abstract
Radiation therapy plays a critical role in the management of a wide range of hematologic malignancies. It is well known that the post-irradiation damages both in the bone marrow and in other organs are the main causes of post-irradiation morbidity and mortality. Tumor control without producing extensive damage to the surrounding normal cells, through the use of radioprotectors, is of special clinical relevance in radiotherapy. An increasing amount of data is helping to clarify the role of oxidative stress in toxicity and therapy response. Radioprotective agents are substances that moderate the oxidative effects of radiation on healthy normal tissues while preserving the sensitivity to radiation damage in tumor cells. As well as the substances capable of carrying out a protective action against the oxidative damage caused by radiotherapy, other substances have been identified as possible enhancers of the radiotherapy and cytotoxic activity via an oxidative effect. The purpose of this review was to examine the data in the literature on the possible use of old and new substances to increase the efficacy of radiation treatment in hematological diseases and to reduce the harmful effects of the treatment.
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Affiliation(s)
- Andrea Gaetano Allegra
- Radiation Oncology Unit, Department of Biomedical, Experimental, and Clinical Sciences “Mario Serio”, Azienda Ospedaliero-Universitaria Careggi, University of Florence, 50100 Florence, Italy;
| | - Federica Mannino
- Department of Clinical and Experimental Medicine, University of Messina, c/o AOU Policlinico G. Martino, Via C. Valeria Gazzi, 98125 Messina, Italy;
| | - Vanessa Innao
- Department of Human Pathology in Adulthood and Childhood “Gaetano Barresi”, Division of Haematology, University of Messina, 98125 Messina, Italy; (V.I.); (C.M.)
| | - Caterina Musolino
- Department of Human Pathology in Adulthood and Childhood “Gaetano Barresi”, Division of Haematology, University of Messina, 98125 Messina, Italy; (V.I.); (C.M.)
| | - Alessandro Allegra
- Department of Human Pathology in Adulthood and Childhood “Gaetano Barresi”, Division of Haematology, University of Messina, 98125 Messina, Italy; (V.I.); (C.M.)
- Correspondence: ; Tel.: +39-090-221-2364
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D-Galactose-induced oxidative stress and mitochondrial dysfunction in the cochlear basilar membrane: an in vitro aging model. Biogerontology 2020; 21:311-323. [PMID: 32026209 PMCID: PMC7196095 DOI: 10.1007/s10522-020-09859-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 01/29/2020] [Indexed: 12/15/2022]
Abstract
The cochlear basilar membrane (CBM) contains inner hair cells and outer hair cells that convert sound waves into electrical signals and transmit them to the central auditory system. Cochlear aging, the primary reason of age-related hearing loss, can reduce the signal transmission capacity. There is no ideal in vitro aging model of the CBM. In this study, we cultured the CBM, which was dissected from the cochlea of the C57BL/6 mice 5 days after birth, in a medium containing 20 mg/mL, 40 mg/mL, or 60 mg/mL D-galactose (D-gal). Compared with the control group, the levels of senescence-associated β-galactosidase were increased in a concentration-dependent manner in the CBM of the D-gal groups. In addition, levels of the mitochondrial superoxide and patterns of an age-related mitochondrial DNA3860-bp deletion were significantly increased. The ATP levels and the membrane potential of the mitochondrial were significantly decreased in the CBM of the D-gal groups compared with the control group. Furthermore, in comparison with the control group, damaged hair cell stereocilia and a loss of inner hair cell ribbon synapses were observed in the CBM of the D-gal groups. A loss of hair cells and activation of caspase-3-mediated outer hair cell apoptosis were also observed in the CBM of the high-dose D-gal group. These insults induced by D-gal in the CBM in vitro were similar to the ones that occur in cochlear natural aging in vivo. Thus, we believe that this is a successful in vitro aging model using cultured CBM. These results demonstrate the effects of mitochondrial oxidative damage on presbycusis and provide a reliable aging model to study the mechanisms of presbycusis in vitro.
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Du ZD, Han SG, Qu TF, Guo B, Yu SK, Wei W, Feng S, Liu K, Gong SS. Age-related insult of cochlear ribbon synapses: An early-onset contributor to D-galactose-induced aging in mice. Neurochem Int 2019; 133:104649. [PMID: 31870891 DOI: 10.1016/j.neuint.2019.104649] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Revised: 12/15/2019] [Accepted: 12/19/2019] [Indexed: 11/29/2022]
Abstract
Presbycusis results from age-related degeneration of the auditory system. D-galactose (D-gal)-induced aging is an ideal and commonly used animal model in aging research. Previous studies demonstrate that administration of D-gal can activate mitochondria-dependent apoptosis in the cochlear stria vascularis. However, D-gal-induced changes to cochlear inner (IHCs) and outer (OHCs) hair cells, spiral ganglion cells (SGCs), and ribbon synapses connecting IHCs and SGCs have not been systematically reported. The current study investigated changes in the numbers of hair cells, SGCs, and ribbon synapses in the mouse model of aging. We found that in comparison to control mice, the numbers of ribbon synapses and their nerve fibers were significantly decreased in D-gal-treated mice, whereas the numbers of OHCs, IHCs, and SGCs were almost unchanged. Moreover, hair cell stereocilia were also not obviously influenced by D-gal administration. Although D-gal-induced aging did not significantly shift the auditory brainstem response (ABR) thresholds in the 8, 16, and 32 kHz frequency bands, the amplitude and latency of the ABR wave I, reflecting ribbon synapse functions, were abnormal in D-gal-treated mice compared to control mice. We also found that 8-hydroxy-2-deoxyguanosine, a marker of oxidative DNA damage, was significantly increased in mitochondria of cochleae from mice exposed to D-gal-induced aging in comparison to control mice. Moreover, D-gal administration increased the levels of H2O2 and mitochondrial 3860-bp common deletion, and decreased superoxide dismutase activity and ATP production in the cochlea. Furthermore, compared with control mice, the protein levels of NADPH oxidase 2 and uncoupling protein 2 were significantly increased in the cochlea of D-gal-treated mice. Taken together, these findings support that the cochlear ribbon synapse is the primary insult site in the early stage of presbycusis, and mitochondrial oxidative damage and subsequent dysfunctions might be responsible for this insult.
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Affiliation(s)
- Zheng-De Du
- Department of Otorhinolaryngology, Beijing Friendship Hospital, Capital Medical University, 95 Yongan Road, Xicheng District, Beijing, 100050, China
| | - Shu-Guang Han
- Department of Otorhinolaryngology, Beijing Friendship Hospital, Capital Medical University, 95 Yongan Road, Xicheng District, Beijing, 100050, China
| | - Teng-Fei Qu
- Department of Otorhinolaryngology, Beijing Friendship Hospital, Capital Medical University, 95 Yongan Road, Xicheng District, Beijing, 100050, China
| | - Bin Guo
- Department of Otorhinolaryngology, Beijing Friendship Hospital, Capital Medical University, 95 Yongan Road, Xicheng District, Beijing, 100050, China
| | - Shu-Kui Yu
- Department of Otorhinolaryngology, Beijing Friendship Hospital, Capital Medical University, 95 Yongan Road, Xicheng District, Beijing, 100050, China
| | - Wei Wei
- Department of Otology, Shengjing Hospital, China Medical University, 36 Sanhao Street, Heping District, Shenyang, 110004, China
| | - Shuai Feng
- Department of Otorhinolaryngology, The First Hospital of China Medical University, 155 Nanjingbei Street, Heping District, Shenyang, 110000, China
| | - Ke Liu
- Department of Otorhinolaryngology, Beijing Friendship Hospital, Capital Medical University, 95 Yongan Road, Xicheng District, Beijing, 100050, China.
| | - Shu-Sheng Gong
- Department of Otorhinolaryngology, Beijing Friendship Hospital, Capital Medical University, 95 Yongan Road, Xicheng District, Beijing, 100050, China.
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Mitofusins modulate the increase in mitochondrial length, bioenergetics and secretory phenotype in therapy-induced senescent melanoma cells. Biochem J 2019; 476:2463-2486. [PMID: 31431479 PMCID: PMC6735661 DOI: 10.1042/bcj20190405] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 08/08/2019] [Accepted: 08/19/2019] [Indexed: 01/03/2023]
Abstract
Cellular senescence is an endpoint of chemotherapy, and targeted therapies in melanoma and the senescence-associated secretory phenotype (SASP) can affect tumor growth and microenvironment, influencing treatment outcomes. Metabolic interventions can modulate the SASP, and an enhanced mitochondrial energy metabolism supports resistance to therapy in melanoma cells. Herein, we assessed the mitochondrial function of therapy-induced senescent melanoma cells obtained after exposing the cells to temozolomide (TMZ), a methylating chemotherapeutic agent. Senescence induction in melanoma was accompanied by a substantial increase in mitochondrial basal, ATP-linked, and maximum respiration rates and in coupling efficiency, spare respiratory capacity, and respiratory control ratio. Further examinations revealed an increase in mitochondrial mass and length. Alterations in mitochondrial function and morphology were confirmed in isolated senescent cells, obtained by cell-size sorting. An increase in mitofusin 1 and 2 (MFN1 and 2) expression and levels was observed in senescent cells, pointing to alterations in mitochondrial fusion. Silencing mitofusin expression with short hairpin RNA (shRNA) prevented the increase in mitochondrial length, oxygen consumption rate and secretion of interleukin 6 (IL-6), a component of the SASP, in melanoma senescent cells. Our results represent the first in-depth study of mitochondrial function in therapy-induced senescence in melanoma. They indicate that senescence increases mitochondrial mass, length and energy metabolism; and highlight mitochondria as potential pharmacological targets to modulate senescence and the SASP.
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8
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Du ZD, He L, Tu C, Guo XA, Yu S, Liu K, Gong S. Mitochondrial DNA 3,860-bp Deletion Increases with Aging in the Auditory Nervous System of C57BL/6J Mice. ORL J Otorhinolaryngol Relat Spec 2019; 81:92-100. [PMID: 31129670 DOI: 10.1159/000499475] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/08/2019] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS Mitochondrial DNA (mtDNA) is sensitive to oxidative damage during aging, which can result in mtDNA mutations. A previous study reported that a 3,860-bp mtDNA deletion, similar to a 4,977-bp mtDNA deletion in humans, is also common occurrence in murine tissues, and increases in the brain and liver with aging. However, no previous study evaluated both topics in the murine auditory nervous system. METHODS We compared mtDNA oxidative damage, mitochondrial ultrastructural changes, and the frequency of the 3,860-bp deletion in the peripheral (spiral ganglion, SG) and central (auditory cortex, AC) auditory nervous system of C57BL/6J mice aged 2, 12, and 18 months. RESULTS We found that the threshold of auditory brainstem response increased with age along with the signal of 8-hydroxy-2'-deoxyguanosine - a marker of DNA oxidative damage - in the mitochondria of SG and AC neurons. The mitochondrial ultrastructural damage also increased with aging in the SG and AC neurons. Moreover, the relative amount of mtDNA 3,860-bp deletion in 12- and 18-month-old mice was significantly higher in the SG and AC as compared to 2-month-old mice. CONCLUSION These results suggest that the mtDNA 3,860-bp deletion is common in the auditory nervous system of mice and increases with age and may contribute to age-related hearing loss.
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Affiliation(s)
- Zheng-De Du
- Department of Otorhinolaryngology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Lu He
- Department of Otorhinolaryngology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Chunmei Tu
- Department of Otorhinolaryngology, First People's Hospital of Jinan, Jinan, China
| | - Xiao-An Guo
- Department of Otorhinolaryngology, First Affiliated Hospital of China Medical University, Shenyang, China
| | - Shukui Yu
- Department of Otorhinolaryngology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Ke Liu
- Department of Otorhinolaryngology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Shusheng Gong
- Department of Otorhinolaryngology, Beijing Friendship Hospital, Capital Medical University, Beijing, China,
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Ma H, Martin K, Dixon D, Hernandez AG, Weber GM. Transcriptome analysis of egg viability in rainbow trout, Oncorhynchus mykiss. BMC Genomics 2019; 20:319. [PMID: 31029084 PMCID: PMC6486991 DOI: 10.1186/s12864-019-5690-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 04/11/2019] [Indexed: 12/31/2022] Open
Abstract
Background Maternal transcripts are accumulated in the oocyte during oogenesis to provide for protein synthesis from oocyte maturation through early embryonic development, when nuclear transcription is silenced. The maternal mRNAs have short poly(A) tails after undergoing post-transcriptional processing necessary for stabilizing them for storage. The transcripts undergo cytoplasmic polyadenylation when they are to be translated. Transcriptome analyses comparing total mRNA and elongated poly(A) mRNA content among eggs of different quality can provide insight into molecular mechanisms affecting egg developmental competence in rainbow trout. The present study used RNA-seq to compare transcriptomes of unfertilized eggs of rainbow trout females yielding different eyeing rates, following rRNA removal and poly(A) retention for construction of the libraries. Results The percentage of embryos to reach the 32-cell stage at 24 h post fertilization was significantly correlated to family eyeing rate, indicating that inviable embryos were developmentally compromised before zygotic genome activation. RNA sequencing identified 2 differentially expressed transcripts (DETs) from total mRNA sequencing comparing females with low-quality (< 5% eyeing), medium-quality (30–50% eyeing), and high-quality (> 80% eyeing) eggs. In contrast, RNA sequencing from poly(A) captured transcripts identified 945 DETs between low- and high-quality eggs, 1012 between low- and medium-quality eggs, and only 2 between medium- and high-quality eggs. The transcripts of mitochondrial genes were enriched with polyadenylated transcript sequencing and they were significantly reduced in low-quality eggs. Similarly, mitochondrial DNA was reduced in low-quality eggs compared with medium- and high-quality eggs. The functional gene analysis classified the 945 DETs between low- and high-quality eggs into 31 functional modules, many of which were related to ribosomal and mitochondrial functions. Other modules involved transcription, translation, cell division, apoptosis, and immune responses. Conclusions Our results indicate that differences in egg quality may be derived from differences in maternal nuclear transcript activation and cytoplasmic polyadenylation before ovulation, as opposed to accumulation and storage of maternal nuclear transcripts during oogenesis. Transcriptome comparisons suggest low-quality eggs suffered from impaired oxidative phosphorylation and translation. The DETs identified in this study provide insight into developmental competence in rainbow trout eggs. Electronic supplementary material The online version of this article (10.1186/s12864-019-5690-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hao Ma
- USDA/ARS National Center for Cool and Cold Water Aquaculture, Kearneysville, WV, USA
| | | | | | | | - Gregory M Weber
- USDA/ARS National Center for Cool and Cold Water Aquaculture, Kearneysville, WV, USA.
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Borghini A, Vecoli C, Piccaluga E, Guagliumi G, Picano E, Andreassi MG. Increased mitochondrial DNA4977-bp deletion in catheterization laboratory workers with long-term low-dose exposure to ionizing radiation. Eur J Prev Cardiol 2019; 26:976-984. [PMID: 30782005 DOI: 10.1177/2047487319831495] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AIMS Ionizing radiation may lead to mitochondrial DNA (mtDNA) mutations and changes in mtDNA content in cells, major driving mechanisms for carcinogenesis, vascular aging and neurodegeneration. The aim of this study was to investigate the possible induction of common mitochondrial deletion (mtDNA4977) and mtDNA copy number (mtDNA-CN) changes in peripheral blood of personnel working in high-volume cardiac catheterization laboratories (Cath Labs). METHODS A group of 147 Cath Lab workers (median individual effective dose = 16.8 mSv, for the 41 with lifetime dosimetric record) and 74 unexposed individuals were evaluated. The occupational radiological risk score was computed for each subject on the basis of the length of employment, individual caseload and proximity to the radiation source. mtDNA4977 deletion and mtDNA-CN were assessed by using quantitative real-time polymerase chain reaction. RESULTS Increased levels of mtDNA4977 deletion were observed in high-exposure Cath Lab workers compared with unexposed individuals ( p < 0.0001). Conversely, mtDNA-CN was significantly greater in the low-exposure workers ( p = 0.003). Occupational radiological risk score was positively correlated with mtDNA4977 deletion (Spearman's r = 0.172, p = 0.03) and inversely correlated with mtDNA-CN (Spearman's r = -0.202, p = 0.01). In multiple regression model, occupational radiological risk score emerged as significant predictor of high levels of mtDNA4977 deletion (ß coefficient = 0.236, p = 0.04). CONCLUSION mtDNA4977 deletion is significantly high in Cath Lab personnel. Beyond the well-recognized nuclear DNA, mtDNA damage might deserve attention as a pathogenetic molecular pathway and a potential therapeutic target of ionizing radiation damage.
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Affiliation(s)
| | | | | | - Giulio Guagliumi
- 3 Ospedale Papa Giovanni XXIII, Cardiovascular Department, Bergamo, Italy
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Kawamura K, Qi F, Kobayashi J. Potential relationship between the biological effects of low-dose irradiation and mitochondrial ROS production. JOURNAL OF RADIATION RESEARCH 2018; 59:ii91-ii97. [PMID: 29415254 PMCID: PMC5941154 DOI: 10.1093/jrr/rrx091] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 09/04/2017] [Accepted: 01/05/2018] [Indexed: 05/22/2023]
Abstract
Exposure to ionizing radiation (IR) induces various types of DNA damage, of which DNA double-strand breaks are the most severe, leading to genomic instability, tumorigenesis, and cell death. Hence, cells have developed DNA damage responses and repair mechanisms. IR also causes the accumulation of endogenous reactive oxidative species (ROS) in the irradiated cells. Upon exposure to low-dose irradiation, the IR-induced biological effects mediated by ROS were relatively more significant than those mediated by DNA damage. Accumulating evidence suggests that such increase in endogenous ROS is related with mitochondria change in irradiated cells. Thus, in this review we focused on the mechanism of mitochondrial ROS production and its relationship to the biological effects of IR. Exposure of mammalian cells to IR stimulates an increase in the production of endogenous ROS by mitochondria, which potentially leads to mitochondrial dysfunction. Since the remains of damaged mitochondria could generate or leak more ROS inside the cell, the damaged mitochondria are removed by mitophagy. The disruption of this pathway, involved in maintaining mitochondrial integrity, could lead to several disorders (such as neurodegeneration) and aging. Thus, further investigation needs to be performed in order to understand the relationship between the biological effects of low-dose IR and mitochondrial integrity.
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Affiliation(s)
- Kasumi Kawamura
- Department of Interdisciplinary Environment, Graduate School of Human and Environmental Sciences, Kyoto University, Yoshidanihonmatsucho, Sakyo-ku, Kyoto 606-8501, Japan
- Department of Genome Repair Dynamics, Radiation Biology Center, Kyoto University, Yoshidakonoecho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Fei Qi
- Department of Interdisciplinary Environment, Graduate School of Human and Environmental Sciences, Kyoto University, Yoshidanihonmatsucho, Sakyo-ku, Kyoto 606-8501, Japan
- Department of Genome Repair Dynamics, Radiation Biology Center, Kyoto University, Yoshidakonoecho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Junya Kobayashi
- Department of Interdisciplinary Environment, Graduate School of Human and Environmental Sciences, Kyoto University, Yoshidanihonmatsucho, Sakyo-ku, Kyoto 606-8501, Japan
- Department of Genome Repair Dynamics, Radiation Biology Center, Kyoto University, Yoshidakonoecho, Sakyo-ku, Kyoto 606-8501, Japan
- Corresponding author. Department of Genome Repair Dynamics, Radiation Biology Center, Kyoto University, Yoshidakonoecho, Sakyo-ku, Kyoto 606-8501, Japan. Tel: +81-75-753-7554; Fax: +81-75-753-7564;
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Chestkov IV, Jestkova EM, Ershova ES, Golimbet VG, Lezheiko TV, Kolesina NY, Dolgikh OA, Izhevskaya VL, Kostyuk GP, Kutsev SI, Veiko NN, Kostyuk SV. ROS-Induced DNA Damage Associates with Abundance of Mitochondrial DNA in White Blood Cells of the Untreated Schizophrenic Patients. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:8587475. [PMID: 29682166 PMCID: PMC5845523 DOI: 10.1155/2018/8587475] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 11/01/2017] [Accepted: 12/10/2017] [Indexed: 02/06/2023]
Abstract
OBJECTIVE The aim of this study was (1) to examine the leukocyte mtDNA copy number (CN) in unmedicated (SZ (m-)) and medicated (SZ (m+)) male patients with paranoid schizophrenia (SZ) in comparison with the healthy male controls (HC) and (2) to compare the leukocyte mtDNA CN with the content of an oxidation marker 8-oxodG in lymphocytes of the SZ (m-) patients. METHODS We evaluated leukocyte mtDNA CN of 110 subjects with SZ in comparison with 60 male HC by the method qPCR (ratio mtDNA/nDNA (gene B2M) was detected). SZ patients were divided into two subgroups. The patients of the subgroups SZ (m+) (N = 55) were treated with standard antipsychotic medications in the hospital. The patients of the subgroup SZ (m-) (N = 55) were not treated before venous blood was sampled. To evaluate oxidative DNA damage, we quantified the levels of 8-oxodG in lymphocytes (flow cytometry) of SZ (m-) patients (N = 55) and HC (N = 30). RESULTS The leukocyte mtDNA CN showed no significant difference in SZ (m+) patients and HC. The mtDNA CN in the unmedicated subgroup SZ (m-) was significantly higher than that in the SZ (m+) subgroup or in HC group. The level of 8-oxodG in the subgroup SZ (m-) was significantly higher than that in HC group. CONCLUSION The leukocytes of the unmedicated SZ male patients with acute psychosis contain more mtDNA than the leukocytes of the male SZ patients treated with antipsychotic medications or the healthy controls. MtDNA content positively correlates with the level of 8-oxodG in the unmedicated SZ patients.
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Affiliation(s)
- I. V. Chestkov
- Research Centre for Medical Genetics (RCMG), Moscow 115478, Russia
| | - E. M. Jestkova
- N. A. Alexeev Clinical Psychiatric Hospital №1 of Moscow Healthcare Department, Moscow 115447, Russia
| | - E. S. Ershova
- Research Centre for Medical Genetics (RCMG), Moscow 115478, Russia
- V. A. Negovsky Research Institute of General Reanimatology, Federal Clinical Research Center of Reanimatology and Rehabilitogy, Moscow 107031, Russia
| | | | | | | | - O. A. Dolgikh
- Research Centre for Medical Genetics (RCMG), Moscow 115478, Russia
| | - V. L. Izhevskaya
- Research Centre for Medical Genetics (RCMG), Moscow 115478, Russia
| | - G. P. Kostyuk
- N. A. Alexeev Clinical Psychiatric Hospital №1 of Moscow Healthcare Department, Moscow 115447, Russia
| | - S. I. Kutsev
- Research Centre for Medical Genetics (RCMG), Moscow 115478, Russia
| | - N. N. Veiko
- Research Centre for Medical Genetics (RCMG), Moscow 115478, Russia
- V. A. Negovsky Research Institute of General Reanimatology, Federal Clinical Research Center of Reanimatology and Rehabilitogy, Moscow 107031, Russia
| | - S. V. Kostyuk
- Mental Health Research Center, Moscow 115522, Russia
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13
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Lee AY, Jang Y, Hong SH, Chang SH, Park S, Kim S, Kang KS, Kim JE, Cho MH. Ephedrine-induced mitophagy via oxidative stress in human hepatic stellate cells. J Toxicol Sci 2017; 42:461-473. [PMID: 28717105 DOI: 10.2131/jts.42.461] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
The herb Ephedra sinica (also known as Chinese ephedra or Ma Huang), used in traditional Chinese medicine, contains alkaloids identical to ephedrine and pseudoephedrine as its principal active constituents. Recent studies have reported that ephedrine has various side effects in the cardiovascular and nervous systems. In addition, herbal Ephedra, a plant containing many pharmacologically active alkaloids, principally ephedrine, has been reported to cause acute hepatitis. Many studies reported clinical cases, however, the cellular mechanism of liver toxicity by ephedrine remains unknown. In this study, we investigated hepatotoxicity and key regulation of mitophagy in ephedrine-treated LX-2 cells. Ephedrine triggered mitochondrial oxidative stress and depolarization. Mitochondrial swelling and autolysosome were observed in ephedrine-treated cells. Ephedrine also inhibited mitochondrial biogenesis, and the mitochondrial copy number was decreased. Parkin siRNA recovered the ephedrine-induced mitochondrial damage. Excessive mitophagy lead to cell death through imbalance of autophagic flux. Moreover, antioxidants and reducing Parkin level could serve as therapeutic targets for ephedrine-induced hepatotoxicity.
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Affiliation(s)
- Ah Young Lee
- Laboratory of Toxicology, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Korea
| | - Yoonjeong Jang
- Laboratory of Toxicology, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Korea
| | - Seong-Ho Hong
- Laboratory of Toxicology, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Korea.,Present address: New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Korea
| | - Seung-Hee Chang
- Laboratory of Toxicology, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Korea
| | - Sungjin Park
- Laboratory of Toxicology, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Korea.,Present address: Department of Pharmacology and Medical Science, Metabolic Diseases and Cell Signaling Laboratory, Research Institute for Medical Sciences, College of Medicine, Chungnam National University, Korea
| | - Sanghwa Kim
- Laboratory of Toxicology, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Korea.,Graduate Group of Tumor Biology, Seoul National University, Korea
| | - Kyung-Sun Kang
- Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Korea
| | - Ji-Eun Kim
- Laboratory of Toxicology, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Korea.,Present address: Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Canada
| | - Myung-Haing Cho
- Laboratory of Toxicology, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Korea.,Graduate School of Convergence Science and Technology, Seoul National University, Korea.,Graduate Group of Tumor Biology, Seoul National University, Korea.,Advanced Institute of Convergence Technology, Seoul National University, Korea.,Institute of GreenBio Science Technology, Seoul National University, Korea
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14
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Dannenmann B, Lehle S, Lorscheid S, Huber SM, Essmann F, Schulze-Osthoff K. Simultaneous quantification of DNA damage and mitochondrial copy number by long-run DNA-damage quantification (LORD-Q). Oncotarget 2017; 8:112417-112425. [PMID: 29348835 PMCID: PMC5762520 DOI: 10.18632/oncotarget.20112] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 07/26/2017] [Indexed: 11/29/2022] Open
Abstract
DNA damage and changes in the mitochondrial DNA content have been implicated in ageing and cancer development. To prevent genomic instability and tumorigenesis, cells must maintain the integrity of their nuclear and mitochondrial DNA. Advances in the research of DNA damage protection and genomic stability, however, also depend on the availability of techniques that can reliably quantify alterations of mitochondrial DNA copy numbers and DNA lesions in an accurate high-throughput manner. Unfortunately, no such method has been established yet. Here, we describe the high-sensitivity long-run real-time PCR technique for DNA-damage quantification (LORD-Q) and its suitability to simultaneously measure DNA damage rates and mitochondrial DNA copy numbers in cultured cells and tissue samples. Using the LORD-Q multiplex assay, we exemplarily show that the mitochondrial DNA content does not directly affect DNA damage susceptibility, but influences the efficacy of certain anticancer drugs. Hence, LORD-Q provides a fast and precise method to assess DNA lesions, DNA repair and mtDNA replication as well as their role in a variety of pathological settings.
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Affiliation(s)
- Benjamin Dannenmann
- Department of Molecular Medicine, Interfaculty Institute for Biochemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Simon Lehle
- Department of Molecular Medicine, Interfaculty Institute for Biochemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Sebastian Lorscheid
- Department of Molecular Medicine, Interfaculty Institute for Biochemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Stephan M Huber
- Department of Radiation Oncology, University of Tübingen, 72076 Tübingen, Germany
| | - Frank Essmann
- Department of Molecular Medicine, Interfaculty Institute for Biochemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Klaus Schulze-Osthoff
- Department of Molecular Medicine, Interfaculty Institute for Biochemistry, University of Tübingen, 72076 Tübingen, Germany.,German Cancer Consortium (DKTK) and German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
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15
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Ning X, He J, Shi X, Yu T, Yang G. Wnt3a regulates mitochondrial biogenesis through p38/CREB pathway. Biochem Biophys Res Commun 2016; 516:1019-1025. [PMID: 27150625 DOI: 10.1016/j.bbrc.2016.05.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 05/01/2016] [Indexed: 01/22/2023]
Abstract
Wnt3a is established as an important regulator of various developmental processes, especially in osteogenesis, adipogenesis and mitochondrial biogenesis. Numerous studies reported Wnt3a regulates osteogenesis and adipogenesis, but the mechanisms by which Wnt3a regulates mitochondrial biogenesis are not well understood. In this study, results suggested that Wnt3a stimulates mitochondrial biogenesis by increasing the expression of mitochondrial biogenesis genes and regulators, as well as mitochondrial copy number in adipocytes. As a key mediator of canonical Wnt/β-catenin pathway, β-catenin knockdown had no effect on basal or Wnt3a-mediated mitochondrial biogenesis in adipocytes, which suggested that Wnt3a-mediated mitochondrial biogenesis was independent of β-catenin-dependent canonical Wnt/β-catenin pathway. However, Wnt3a inhibited p38/CREB (p38 mitogen-activated protein kinase/cAMP response element-binding protein) signaling activation and p38 inhibitor impaired Wnt3a-stimulated mitochondrial biogenesis, indicating p38/CREB pathway could be involved in the regulation of Wnt3a-mediated mitochondrial biogenesis in adipocytes. In conclusion, our data showed that Wnt3a stimulates mitochondrial biogenesis in adipocytes, which is at least partially through activation of p38/CREB pathway.
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Affiliation(s)
- Xiaomin Ning
- Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, PR China
| | - Jingjing He
- Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, PR China
| | - Xin'e Shi
- Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, PR China
| | - Taiyong Yu
- Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, PR China
| | - Gongshe Yang
- Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, PR China.
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16
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Liu B, Zhang R, Tao G, Lehwald NC, Liu B, Koh Y, Sylvester KG. Augmented Wnt signaling as a therapeutic tool to prevent ischemia/reperfusion injury in liver: Preclinical studies in a mouse model. Liver Transpl 2015; 21:1533-42. [PMID: 26335930 DOI: 10.1002/lt.24331] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 07/21/2015] [Accepted: 08/27/2015] [Indexed: 01/08/2023]
Abstract
The Wnt signaling pathway has established biological roles in liver development, regeneration, and carcinogenesis. Given the common need for cellular energy utilization in each of these processes, we hypothesized that Wnt signaling would directly regulate hepatocyte mitochondrial function. Mice were engineered to overexpress Wnt1 in hepatocytes under the control of a tetracycline analogue. Wnt1 and wild-type mice underwent ischemia/reperfusion injury (IRI) to induce oxidative mitochondrial injury. Alpha mouse liver 12 (AML12) hepatocytes were exposed to Wnt agonists for in vitro hypoxia/reoxygenation (H-R) experiments. We observed stabilized mitochondrial membrane potential and reduced levels of hepatocyte apoptosis involving the mitochondrial pathway in Wnt1 mice compared to controls following IRI. Wnt1 mice also demonstrated increased mitochondrial DNA copy number, as well as an increased tricarboxylic acid cycle activity and adenosine triphosphate levels indicating that mitochondrial function is preserved by Wnt1 overexpression following IRI. AML12 cells treated by Wnt3a or the glycogen synthase kinase 3β inhibitor LiCl exposed to H-R demonstrated decreased reactive oxygen species and reduced apoptosis compared to controls. Increased nucleus-localized PGC-1α and phosphorylated SIRT1 was observed in both Wnt1+ mice as well as AML12 cells treated with Wnt3a or LiCl. Activated Wnt signaling protects hepatocytes against oxidative injury and apoptosis through mitochondrial stabilization and preserved oxidative phosphorylation function. Mechanistically, these effects are accompanied by an increase in phosphorylated SIRT1 and nucleus-localized PGC-1α. These findings expand the understanding of Wnt signaling biology in hepatocytes and suggest the potential for the therapeutic application of Wnt pathway manipulation in a variety of clinical applications including organ transplantation.
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Affiliation(s)
- Bowen Liu
- Division of Pediatric Surgery, Stanford University School of Medicine, Stanford, CA
| | - Rong Zhang
- Division of Pediatric Surgery, Stanford University School of Medicine, Stanford, CA
| | - Guozhong Tao
- Division of Pediatric Surgery, Stanford University School of Medicine, Stanford, CA
| | - Nadja Corinna Lehwald
- Division of Pediatric Surgery, Stanford University School of Medicine, Stanford, CA.,Department of General, Visceral and Pediatric Surgery, School of Medicine, Heinrich Heine University, Düsseldorf, Germany
| | - Bo Liu
- Division of Pediatric Surgery, Stanford University School of Medicine, Stanford, CA
| | - Yangseok Koh
- Division of Pediatric Surgery, Stanford University School of Medicine, Stanford, CA
| | - Karl G Sylvester
- Division of Pediatric Surgery, Stanford University School of Medicine, Stanford, CA.,Lucile Packard Children's Hospital Stanford, Stanford, CA
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17
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Abdullaev SA, Minkabirova GM, Bezlepkin VG, Gaziev AI. Cell-free DNA in the urine of rats exposed to ionizing radiation. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2015; 54:297-304. [PMID: 25935210 DOI: 10.1007/s00411-015-0599-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 04/27/2015] [Indexed: 06/04/2023]
Abstract
Investigation of cell-free DNA (cf-DNA) in body fluids, as a potential biomarker for assessing the effect of ionizing radiation on the organism, is of considerable interest. We investigated changes in the contents of cell-free mitochondrial DNA (cf-mtDNA) and cell-free nuclear DNA (cf-nDNA) in the urine of X-ray-exposed rats. Assays of cf-mtDNA and cf-nDNA were performed by a real-time PCR in rat urine collected before and after irradiation of animals with doses of 3 and 5 Gy. We also determined the presence of mutations in urine cf-mtDNA, as recognized by Surveyor nuclease. A sharp increase in cf-mtDNA and cf-nDNA in the urine of irradiated rats was observed within 24 h after exposure, followed by a decrease to normal levels. In all cases, the contents of cf-mtDNA fragment copies (estimated by gene tRNA) were significantly higher than those of cf-nDNA estimated by gene GAPDH. A certain portion of mutant cf-mtDNA fragments was detected in the urine of exposed rats, whereas they were absent in the urine of the same animals before irradiation. These preliminary data also suggest that the increased levels of urine cf-mtDNA and cf-nDNA may be a potential biomarker for noninvasive assessment of how the organism responds to ionizing radiation influence.
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Affiliation(s)
- Serazhutdin A Abdullaev
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Science (RAS), Pushchino, Moscow Region, 142290, Russia,
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18
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Chen R, Lin J, Hong J, Han D, Zhang AD, Lan R, Fu L, Wu Z, Lin J, Zhang W, Wang Z, Chen W, Chen C, Zhang H. Potential toxicity of quercetin: The repression of mitochondrial copy number via decreased POLG expression and excessive TFAM expression in irradiated murine bone marrow. Toxicol Rep 2014; 1:450-458. [PMID: 28962259 PMCID: PMC5598249 DOI: 10.1016/j.toxrep.2014.07.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 07/22/2014] [Accepted: 07/22/2014] [Indexed: 11/21/2022] Open
Abstract
The cytotoxicity of quercetin is not well understood. Using an ICR murine model, we unexpectedly found that mice exposed to 7 Gy total body irradiation (TBI) exhibited general in vivo toxicity after receiving quercetin (100 mg/kg PO), whereas this result was not observed in mice that received TBI only. In order to understand the involvement of alterations in mitochondrial biogenesis, we used a real-time qPCR to analyze the mitochondrial DNA copy number (mtDNAcn) by amplifying the MTRNR1 (12S rRNA) gene in murine bone marrow. We also utilized reverse transcription qPCR to determine the mRNA amounts transcribed from the polymerase gamma (POLG), POLG2, and mammalian mitochondrial transcription factor A (TFAM) genes in the tissue. In the mice exposed to TBI combined with quercetin, we found: (1) the radiation-induced increase of mtDNAcn was inhibited with a concurrent significant decrease in POLG expression; (2) TFAM expression was significantly increased; and (3) the expression of POLG2 was not influenced by the treatments. These data suggest that the overall toxicity was in part associated with the decrease in mtDNAcn, an effect apparently caused by the inhibition of POLG expression and overexpression of TFAM; unaltered POLG2 expression did not seem to contribute to toxicity.
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Affiliation(s)
- Ruiqing Chen
- Central Laboratory, First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Jingan Lin
- Central Laboratory, First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Jingshen Hong
- Central Laboratory, First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Deping Han
- Central Laboratory, First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Addison D Zhang
- Central Laboratory, First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Ruilong Lan
- Central Laboratory, First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Lengxi Fu
- Central Laboratory, First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Zhaoyang Wu
- Department of Orthopedics, First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Jianhua Lin
- Central Laboratory, First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Weijian Zhang
- Central Laboratory, First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Zeng Wang
- Central Laboratory, First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Wei Chen
- Central Laboratory, First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Chun Chen
- Central Laboratory, First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
| | - Hengshan Zhang
- Central Laboratory, First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China
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19
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Zhang SB, Maguire D, Zhang M, Tian Y, Yang S, Zhang A, Casey-Sawicki K, Han D, Ma J, Yin L, Guo Y, Wang X, Chen C, Litvinchuk A, Zhang Z, Swarts S, Vidyasagar S, Zhang L, Okunieff P. Mitochondrial DNA and functional investigations into the radiosensitivity of four mouse strains. Int J Cell Biol 2014; 2014:850460. [PMID: 24688546 PMCID: PMC3944901 DOI: 10.1155/2014/850460] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 12/06/2013] [Indexed: 12/25/2022] Open
Abstract
We investigated whether genetic radiosensitivity-related changes in mtDNA/nDNA ratios are significant to mitochondrial function and if a material effect on mtDNA content and function exists. BALB/c (radiosensitive), C57BL/6 (radioresistant), and F1 hybrid mouse strains were exposed to total body irradiation. Hepatic genomic DNA was extracted, and mitochondria were isolated. Mitochondrial oxygen consumption, ROS, and calcium-induced mitochondrial swelling were measured. Radiation influenced strain-specific survival in vivo. F1 hybrid survival was influenced by maternal input. Changes in mitochondrial content corresponded to survival in vivo among the 4 strains. Calcium-induced mitochondrial swelling was strain dependent. Isolated mitochondria from BALB/c mice were significantly more sensitive to calcium overload than mitochondria from C57BL/6 mice. Maternal input partially influenced the recovery effect of radiation on calcium-induced mitochondrial swelling in F1 hybrids; the hybrid with a radiosensitive maternal lineage exhibited a lower rate of recovery. Hybrids had a survival rate that was biased toward maternal input. mtDNA content and mitochondrial permeability transition pores (MPTP) measured in these strains before irradiation reflected a dominant input from the parent. After irradiation, the MPTP opened sooner in radiosensitive and hybrid strains, likely triggering intrinsic apoptotic pathways. These findings have important implications for translation into predictors of radiation sensitivity/resistance.
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Affiliation(s)
- Steven B. Zhang
- Department of Radiation Oncology, University of Florida Shands Cancer Center, 2033 Mowry Road, P.O. Box 103633, Gainesville, FL 32610, USA
| | - David Maguire
- Department of Radiation Oncology, University of Florida Shands Cancer Center, 2033 Mowry Road, P.O. Box 103633, Gainesville, FL 32610, USA
| | - Mei Zhang
- Department of Radiation Oncology, University of Florida Shands Cancer Center, 2033 Mowry Road, P.O. Box 103633, Gainesville, FL 32610, USA
| | - Yeping Tian
- Department of Immunology, Second Military Medical University, Shanghai 200433, China
| | - Shanmin Yang
- Department of Radiation Oncology, University of Florida Shands Cancer Center, 2033 Mowry Road, P.O. Box 103633, Gainesville, FL 32610, USA
| | - Amy Zhang
- Department of Radiation Oncology, University of Florida Shands Cancer Center, 2033 Mowry Road, P.O. Box 103633, Gainesville, FL 32610, USA
| | - Katherine Casey-Sawicki
- Department of Radiation Oncology, University of Florida Shands Cancer Center, 2033 Mowry Road, P.O. Box 103633, Gainesville, FL 32610, USA
| | - Deping Han
- First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350108, China
| | - Jun Ma
- Institute of Digestive Diseases, Zhengzhou University, Henan 45001, China
| | - Liangjie Yin
- Department of Radiation Oncology, University of Florida Shands Cancer Center, 2033 Mowry Road, P.O. Box 103633, Gainesville, FL 32610, USA
| | - Yongson Guo
- Department of Cardiovascular Diseases, Hospital of Fujian Province, Fuzhou 350004, China
| | - Xiaohui Wang
- Department of Physiology, Shanghai University of Sport, Shanghai 100044, China
| | - Chun Chen
- First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350108, China
| | - Alexandra Litvinchuk
- Institute of Radiobiology, National Academy of Sciences of Belarus, 220072 Gomel, Belarus
| | - Zhenhuan Zhang
- Department of Radiation Oncology, University of Florida Shands Cancer Center, 2033 Mowry Road, P.O. Box 103633, Gainesville, FL 32610, USA
| | - Steven Swarts
- Department of Radiation Oncology, University of Florida Shands Cancer Center, 2033 Mowry Road, P.O. Box 103633, Gainesville, FL 32610, USA
| | - Sadasivan Vidyasagar
- Department of Radiation Oncology, University of Florida Shands Cancer Center, 2033 Mowry Road, P.O. Box 103633, Gainesville, FL 32610, USA
| | - Lurong Zhang
- Department of Radiation Oncology, University of Florida Shands Cancer Center, 2033 Mowry Road, P.O. Box 103633, Gainesville, FL 32610, USA
| | - Paul Okunieff
- Department of Radiation Oncology, University of Florida Shands Cancer Center, 2033 Mowry Road, P.O. Box 103633, Gainesville, FL 32610, USA
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20
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Kam WWY, Banati RB. Effects of ionizing radiation on mitochondria. Free Radic Biol Med 2013; 65:607-619. [PMID: 23892359 DOI: 10.1016/j.freeradbiomed.2013.07.024] [Citation(s) in RCA: 238] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 07/16/2013] [Accepted: 07/16/2013] [Indexed: 01/08/2023]
Abstract
The current concept of radiobiology posits that damage to the DNA in the cell nucleus is the primary cause for the detrimental effects of radiation. However, emerging experimental evidence suggests that this theoretical framework is insufficient for describing extranuclear radiation effects, particularly the response of the mitochondria, an important site of extranuclear, coding DNA. Here, we discuss experimental observations of the effects of ionizing radiation on the mitochondria at (1) the DNA and (2) functional levels. The roles of mitochondria in (3) oxidative stress and (4) late radiation effects are discussed. In this review, we summarize the current understanding of targets for ionizing radiation outside the cell nucleus. Available experimental data suggest that an increase in the tumoricidal efficacy of radiation therapy might be achievable by targeting mitochondria. Likewise, more specific protection of mitochondria and its coding DNA should reduce damage to healthy cells exposed to ionizing radiation.
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Affiliation(s)
- Winnie Wai-Ying Kam
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Sydney, New South Wales 2234, Australia; Medical Radiation Sciences, Faculty of Health Sciences, University of Sydney, Cumberland, Sydney, New South Wales 2141, Australia.
| | - Richard B Banati
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Sydney, New South Wales 2234, Australia; Medical Radiation Sciences, Faculty of Health Sciences, University of Sydney, Cumberland, Sydney, New South Wales 2141, Australia; National Imaging Facility at Brain and Mind Research Institute (BMRI), University of Sydney, Camperdown, Sydney, New South Wales 2050, Australia
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21
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Yu J, Wang Q, Chen N, Sun Y, Wang X, Wu L, Chen S, Yuan H, Xu A, Wang J. Mitochondrial transcription factor A regulated ionizing radiation-induced mitochondrial biogenesis in human lung adenocarcinoma A549 cells. JOURNAL OF RADIATION RESEARCH 2013; 54:998-1004. [PMID: 23645454 PMCID: PMC3823773 DOI: 10.1093/jrr/rrt046] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 03/12/2013] [Accepted: 03/23/2013] [Indexed: 06/02/2023]
Abstract
Mitochondrial transcription factor A (TFAM), the first well-characterized transcription factor from vertebrate mitochondria, is closely related to mitochondrial DNA (mtDNA) maintenance and repair. Recent evidence has shown that the ratio of mtDNA to nuclearDNA (nDNA) is increased in both human cells and murine tissues after ionizing radiation (IR). However, the underlying mechanism has not as yet been clearly identified. In the present study, we demonstrated that in human lung adenocarcinoma A549 cells, expression of TFAM was upregulated, together with the increase of the relative mtDNA copy number and cytochrome c oxidase (COX) activity after α-particle irradiation. Furthermore, short hairpin RNA (shRNA)-mediated TFAM knockdown inhibited the enhancement of the relative mtDNA copy number and COX activity caused by α-particles. Taken together, our data suggested that TFAM plays a crucial role in regulating mtDNA amplification and mitochondrial biogenesis under IR conditions.
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Affiliation(s)
- Jing Yu
- School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230027, PR China
- Key Laboratory of Ion Beam Bioengineering, Chinese Academy of Sciences, Shushan Road No. 350, Hefei 230031, PR China
| | - Qisen Wang
- Key Laboratory of Ion Beam Bioengineering, Chinese Academy of Sciences, Shushan Road No. 350, Hefei 230031, PR China
| | - Ni Chen
- School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230027, PR China
- Key Laboratory of Ion Beam Bioengineering, Chinese Academy of Sciences, Shushan Road No. 350, Hefei 230031, PR China
| | - Yuxiang Sun
- Key Laboratory of Ion Beam Bioengineering, Chinese Academy of Sciences, Shushan Road No. 350, Hefei 230031, PR China
| | - Xiaofei Wang
- Key Laboratory of Ion Beam Bioengineering, Chinese Academy of Sciences, Shushan Road No. 350, Hefei 230031, PR China
| | - Lijun Wu
- School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230027, PR China
- Key Laboratory of Ion Beam Bioengineering, Chinese Academy of Sciences, Shushan Road No. 350, Hefei 230031, PR China
| | - Shaopeng Chen
- Key Laboratory of Ion Beam Bioengineering, Chinese Academy of Sciences, Shushan Road No. 350, Hefei 230031, PR China
| | - Hang Yuan
- Key Laboratory of Ion Beam Bioengineering, Chinese Academy of Sciences, Shushan Road No. 350, Hefei 230031, PR China
| | - An Xu
- Key Laboratory of Ion Beam Bioengineering, Chinese Academy of Sciences, Shushan Road No. 350, Hefei 230031, PR China
| | - Jun Wang
- Key Laboratory of Ion Beam Bioengineering, Chinese Academy of Sciences, Shushan Road No. 350, Hefei 230031, PR China
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22
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Zhang SB, Maguire D, Zhang M, Zhang Z, Zhang A, Yin L, Zhang L, Huang L, Vidyasagar S, Swarts S, Okunieff P. The murine common deletion: mitochondrial DNA 3,860-bp deletion after irradiation. Radiat Res 2013; 180:407-13. [PMID: 24059680 DOI: 10.1667/rr3373.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
This study demonstrates that mice, similar to humans, have a common mitochondrial DNA deletion (3,860 bp) that encodes 5 transfer RNA genes and 5 polypeptide genes that is related to aging, tissue type and radiotoxicity. Our research indicates that the deletion ratio in the liver was significantly higher than in the brain and gut tissues of 8-month-old mice, as compared to 8-week-old mice. Our results also demonstrate that tissue type, oxidative metabolic capacity and radiosensitivity influence the 3,860-bp deletion level. Therefore, this 3,860-bp deletion content may serve as a biomarker of aging and oxidative damage in mice.
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Affiliation(s)
- Steven B Zhang
- Department of Radiation Oncology, University of Florida, Cancer and Genetics Research Complex, Gainesville, Florida 32610
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23
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Zhang SB, Maguire D, Zhang M, Zhang A, Zhang L, Swarts S, Okunieff P. Maternal Bias in Mouse Radiosensitivity: The Role of the Mitochondrial PTP. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 789:251-256. [DOI: 10.1007/978-1-4614-7411-1_34] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
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Kam WWY, Lake V, Banos C, Davies J, Banati R. Apparent polyploidization after gamma irradiation: pitfalls in the use of quantitative polymerase chain reaction (qPCR) for the estimation of mitochondrial and nuclear DNA gene copy numbers. Int J Mol Sci 2013; 14:11544-59. [PMID: 23722662 PMCID: PMC3709747 DOI: 10.3390/ijms140611544] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 04/18/2013] [Accepted: 05/16/2013] [Indexed: 12/12/2022] Open
Abstract
Quantitative polymerase chain reaction (qPCR) has been widely used to quantify changes in gene copy numbers after radiation exposure. Here, we show that gamma irradiation ranging from 10 to 100 Gy of cells and cell-free DNA samples significantly affects the measured qPCR yield, due to radiation-induced fragmentation of the DNA template and, therefore, introduces errors into the estimation of gene copy numbers. The radiation-induced DNA fragmentation and, thus, measured qPCR yield varies with temperature not only in living cells, but also in isolated DNA irradiated under cell-free conditions. In summary, the variability in measured qPCR yield from irradiated samples introduces a significant error into the estimation of both mitochondrial and nuclear gene copy numbers and may give spurious evidence for polyploidization.
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Affiliation(s)
- Winnie W. Y. Kam
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Sydney, New South Wales 2234, Australia; E-Mails: (V.L.); (C.B.); (J.D.); (R.B.)
- Medical Radiation Sciences, Faculty of Health Sciences, University of Sydney, Cumberland, Sydney, New South Wales 2141, Australia
- Author to whom correspondence should be addressed; E-Mail: or ; Tel.: +61-2-9717-7241; Fax: +61-2-9717-9262
| | - Vanessa Lake
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Sydney, New South Wales 2234, Australia; E-Mails: (V.L.); (C.B.); (J.D.); (R.B.)
| | - Connie Banos
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Sydney, New South Wales 2234, Australia; E-Mails: (V.L.); (C.B.); (J.D.); (R.B.)
| | - Justin Davies
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Sydney, New South Wales 2234, Australia; E-Mails: (V.L.); (C.B.); (J.D.); (R.B.)
- School of Physics, University of Sydney, Camperdown, Sydney, New South Wales 2006, Australia
| | - Richard Banati
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Sydney, New South Wales 2234, Australia; E-Mails: (V.L.); (C.B.); (J.D.); (R.B.)
- Medical Radiation Sciences, Faculty of Health Sciences, University of Sydney, Cumberland, Sydney, New South Wales 2141, Australia
- National Imaging Facility at Brain and Mind Research Institute (BMRI), University of Sydney, Camperdown, Sydney, New South Wales 2050, Australia
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Zhang M, Zhang B, Guo Y, Zhang L, Yang S, Yin L, Vidyasagar S, Maguire D, Swarts S, Zhang Z, Zhang A, Zhang L, Okunieff P. Alteration of Circulating Mitochondrial DNA Concentration After Irradiation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 765:371-377. [DOI: 10.1007/978-1-4614-4989-8_52] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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26
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The Role of Mitochondrial Proteomic Analysis in Radiological Accidents and Terrorism. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012. [DOI: 10.1007/978-1-4614-4989-8_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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Mori H, Prestwich TC, Reid MA, Longo KA, Gerin I, Cawthorn WP, Susulic VS, Krishnan V, Greenfield A, Macdougald OA. Secreted frizzled-related protein 5 suppresses adipocyte mitochondrial metabolism through WNT inhibition. J Clin Invest 2012; 122:2405-16. [PMID: 22728933 DOI: 10.1172/jci63604] [Citation(s) in RCA: 133] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 05/03/2012] [Indexed: 12/12/2022] Open
Abstract
Preadipocytes secrete several WNT family proteins that act through autocrine/paracrine mechanisms to inhibit adipogenesis. The activity of WNT ligands is often decreased by secreted frizzled-related proteins (SFRPs). Sfrp5 is strongly induced during adipocyte differentiation and increases in adipocytes during obesity, presumably to counteract WNT signaling. We tested the hypothesis that obesity-induced Sfrp5 expression promotes the development of new adipocytes by inhibiting endogenous suppressors of adipogenesis. As predicted, mice that lack functional SFRP5 were resistant to diet-induced obesity. However, counter to our hypothesis, we found that adipose tissue of SFRP5-deficient mice had similar numbers of adipocytes, but a reduction in large adipocytes. Transplantation of adipose tissue from SFRP5-deficient mice into leptin receptor-deficient mice indicated that the effects of SFRP5 deficiency are tissue-autonomous. Mitochondrial gene expression was increased in adipose tissue and cultured adipocytes from SFRP5-deficient mice. In adipocytes, lack of SFRP5 stimulated oxidative capacity through increased mitochondrial activity, which was mediated in part by PGC1α and mitochondrial transcription factor A. WNT3a also increased oxygen consumption and the expression of mitochondrial genes. Thus, our findings support a model of adipogenesis in which SFRP5 inhibits WNT signaling to suppress oxidative metabolism and stimulate adipocyte growth during obesity.
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Affiliation(s)
- Hiroyuki Mori
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
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Delayed Effects of Radiation on Mitochondrial DNA in Radiation-Sensitive Organs. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011. [DOI: 10.1007/978-1-4614-1566-4_21] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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29
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Zhou X, Li N, Wang Y, Wang Y, Zhang X, Zhang H. Effects of X-irradiation on mitochondrial DNA damage and its supercoiling formation change. Mitochondrion 2011; 11:886-92. [DOI: 10.1016/j.mito.2011.07.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Revised: 05/04/2011] [Accepted: 07/22/2011] [Indexed: 01/18/2023]
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Wen Q, Hu Y, Ji F, Qian G. Mitochondrial DNA alterations of peripheral lymphocytes in acute lymphoblastic leukemia patients undergoing total body irradiation therapy. Radiat Oncol 2011; 6:133. [PMID: 21978541 PMCID: PMC3198693 DOI: 10.1186/1748-717x-6-133] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 10/06/2011] [Indexed: 11/28/2022] Open
Abstract
Background Mitochondrial DNA (mtDNA) alterations, including mtDNA copy number and mtDNA 4977 bp common deletion (CD), are key indicators of irradiation-induced damage. The relationship between total body irradiation (TBI) treatment and mtDNA alterations in vivo, however, has not been postulated yet. The aim of this study is to analyze mtDNA alterations in irradiated human peripheral lymphocytes from acute lymphoblastic leukemia (ALL) patients as well as to take them as predictors for radiation toxicity. Methods Peripheral blood lymphocytes were isolated from 26 ALL patients 24 hours after TBI preconditioning (4.5 and 9 Gy, respectively). Extracted DNA was analyzed by real-time PCR method. Results Average 2.31 times mtDNA and 0.53 fold CD levels were observed after 4.5 Gy exposure compared to their basal levels. 9 Gy TBI produced a greater response of both mtDNA and CD levels than 4.5 Gy. Significant inverse correlation was found between mtDNA content and CD level at 4.5 and 9 Gy (P = 0.037 and 0.048). Moreover, mtDNA content of lymphocytes without irradiation was found to be correlated to age. Conclusions mtDNA and CD content may be considered as predictive factors to radiation toxicity.
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Affiliation(s)
- Quan Wen
- Third Department of Oncology, The second affiliated hospital, Third Military Medical University, Chongqing 400037, China
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Elevated mitochondrial DNA copy number and POL-γ expression but decreased expression of TFAM in murine intestine following therapeutic dose irradiation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 701:201-6. [PMID: 21445788 DOI: 10.1007/978-1-4419-7756-4_27] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Mitochondria play pivotal roles in cellular handling of oxygen and in apoptosis, the ordered suicide response of cells to irradiation. The involvement of expression products from the 16.5 kb human mitochondrial genome in these activities has been studied widely. However, little is known about effects of irradiation on mammalian mitochondrial DNA (mtDNA). The relative lack of mtDNA repair mechanisms compared with nuclear DNA (nDNA) predicts particular vulnerability to irradiation. Using a technique developed to ascertain mtDNA:nDNA ratios, we previously showed that this ratio increases dramatically in murine small bowel within 48 hours following whole body irradiation. We now report that those levels continue to rise for four days and remain elevated at close to that level beyond 30 days after 5 Gy of irradiation.We further demonstrate that levels of the mtDNA-specific DNA polymerase-γ (Pol-γ ) also show a sharp and sustained increase during this time course after a 2-Gy dose. Paradoxically, transcription factor A (TFAM), exhibited the directly opposite response.
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Abdullaev SA, Anishchenko SE, Gaziev AI. Mutant copies of mitochondrial DNA in tissues and plasma of mice subjected to X-ray irradiation. Biophysics (Nagoya-shi) 2010. [DOI: 10.1134/s0006350910050283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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