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Alur A, Phillips J, Xu D. Effects of hexavalent chromium on mitochondria and their implications in carcinogenesis. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, TOXICOLOGY AND CARCINOGENESIS 2024; 42:109-125. [PMID: 38230947 DOI: 10.1080/26896583.2024.2301899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Hexavalent chromium (Cr(VI)) is a well-known occupational and environmental human carcinogen. The cellular effect of Cr(VI) is complex and often nonspecific due to its ability to modulate multiple cellular targets. The toxicity of Cr(VI) is strongly linked to the generation of reactive oxygen species (ROS) during its reduction process. ROS can cause oxidation of cellular macromolecules, such as proteins, lipids, and DNA, thereby altering their functions. A major genotoxic effect of Cr(VI) that contributes to carcinogenesis is the formation of DNA adducts, which can lead to DNA damage. Modulations of cellular signaling pathways and epigenetics may also contribute to the carcinogenic effects of Cr(VI). Cr(VI) has a major impact on many aspects of mitochondrial biology, including oxidative phosphorylation, mitophagy, and mitochondrial biogenesis. These effects have the potential to alter the trajectory of Cr(VI)-induced carcinogenic process. This perspective article summarizes current understandings of the effect of Cr(VI) on mitochondria and discusses the future directions of research in this area, particularly with regard to carcinogenesis.
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Affiliation(s)
- Anish Alur
- Department of Pathology, Microbiology and Immunology, New York Medical College School of Medicine, Valhalla, NY, USA
| | - John Phillips
- Department of Urology, New York Medical College School of Medicine, Valhalla, NY, USA
| | - Dazhong Xu
- Department of Pathology, Microbiology and Immunology, New York Medical College School of Medicine, Valhalla, NY, USA
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2
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Wang W, Tan J, Liu X, Guo W, Li M, Liu X, Liu Y, Dai W, Hu L, Wang Y, Lu Q, Lee WX, Tang HW, Zhou Q. Cytoplasmic Endonuclease G promotes nonalcoholic fatty liver disease via mTORC2-AKT-ACLY and endoplasmic reticulum stress. Nat Commun 2023; 14:6201. [PMID: 37794041 PMCID: PMC10550995 DOI: 10.1038/s41467-023-41757-x] [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: 02/08/2023] [Accepted: 09/06/2023] [Indexed: 10/06/2023] Open
Abstract
Endonuclease G (ENDOG), a nuclear-encoded mitochondrial intermembrane space protein, is well known to be translocated into the nucleus during apoptosis. Recent studies have shown that ENDOG might enter the mitochondrial matrix to regulate mitochondrial genome cleavage and replication. However, little is known about the role of ENDOG in the cytosol. Our previous work showed that cytoplasmic ENDOG competitively binds with 14-3-3γ, which released TSC2 to repress mTORC1 signaling and induce autophagy. Here, we demonstrate that cytoplasmic ENDOG could also release Rictor from 14-3-3γ to activate the mTORC2-AKT-ACLY axis, resulting in acetyl-CoA production. Importantly, we observe that ENDOG could translocate to the ER, bind with Bip, and release IRE1a/PERK to activate the endoplasmic reticulum stress response, promoting lipid synthesis. Taken together, we demonstrate that loss of ENDOG suppresses acetyl-CoA production and lipid synthesis, along with reducing endoplasmic reticulum stress, which eventually alleviates high-fat diet-induced nonalcoholic fatty liver disease in female mice.
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Affiliation(s)
- Wenjun Wang
- The Sixth Affiliated Hospital of Jinan University (Dongguan Eastern Central Hospital), Jinan University, Dongguan, Guangdong, 523067, China.
- The Biomedical Translational Research Institute, Health Science Center (School of Medicine), Jinan University, Guangzhou, Guangdong, 510632, China.
| | - Junyang Tan
- The Sixth Affiliated Hospital of Jinan University (Dongguan Eastern Central Hospital), Jinan University, Dongguan, Guangdong, 523067, China
- The Biomedical Translational Research Institute, Health Science Center (School of Medicine), Jinan University, Guangzhou, Guangdong, 510632, China
| | - Xiaomin Liu
- The Sixth Affiliated Hospital of Jinan University (Dongguan Eastern Central Hospital), Jinan University, Dongguan, Guangdong, 523067, China
- The Biomedical Translational Research Institute, Health Science Center (School of Medicine), Jinan University, Guangzhou, Guangdong, 510632, China
| | - Wenqi Guo
- The Sixth Affiliated Hospital of Jinan University (Dongguan Eastern Central Hospital), Jinan University, Dongguan, Guangdong, 523067, China
- The Biomedical Translational Research Institute, Health Science Center (School of Medicine), Jinan University, Guangzhou, Guangdong, 510632, China
| | - Mengmeng Li
- The Sixth Affiliated Hospital of Jinan University (Dongguan Eastern Central Hospital), Jinan University, Dongguan, Guangdong, 523067, China
- The Biomedical Translational Research Institute, Health Science Center (School of Medicine), Jinan University, Guangzhou, Guangdong, 510632, China
| | - Xinjie Liu
- The Sixth Affiliated Hospital of Jinan University (Dongguan Eastern Central Hospital), Jinan University, Dongguan, Guangdong, 523067, China
- The Biomedical Translational Research Institute, Health Science Center (School of Medicine), Jinan University, Guangzhou, Guangdong, 510632, China
| | - Yanyan Liu
- The Sixth Affiliated Hospital of Jinan University (Dongguan Eastern Central Hospital), Jinan University, Dongguan, Guangdong, 523067, China
- The Biomedical Translational Research Institute, Health Science Center (School of Medicine), Jinan University, Guangzhou, Guangdong, 510632, China
| | - Wenyu Dai
- The Sixth Affiliated Hospital of Jinan University (Dongguan Eastern Central Hospital), Jinan University, Dongguan, Guangdong, 523067, China
- The Biomedical Translational Research Institute, Health Science Center (School of Medicine), Jinan University, Guangzhou, Guangdong, 510632, China
| | - Liubing Hu
- The First Affiliated Hospital, Jinan University, Guangzhou, Guangdong, 510632, China
| | - Yimin Wang
- GeneMind Biosciences Company Limited, No. 116, Qingshuihe 1st Road, Luohu District, Shenzhen, Guangdong, 518000, China
| | - Qiuxia Lu
- School of Food and Biological Engineering, Chengdu University, Chengdu, 610106, China
| | - Wen Xing Lee
- Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, 8 College Road, Singapore, 169857, Singapore
| | - Hong-Wen Tang
- Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, 8 College Road, Singapore, 169857, Singapore
- Division of Cellular & Molecular Research, Humphrey Oei Institute of Cancer Research, National Cancer Centre Singapore, Singapore, 169610, Singapore
| | - Qinghua Zhou
- The Sixth Affiliated Hospital of Jinan University (Dongguan Eastern Central Hospital), Jinan University, Dongguan, Guangdong, 523067, China.
- The Biomedical Translational Research Institute, Health Science Center (School of Medicine), Jinan University, Guangzhou, Guangdong, 510632, China.
- The First Affiliated Hospital, Jinan University, Guangzhou, Guangdong, 510632, China.
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Chang YH, Kang EYC, Liu L, Jenny LA, Khang R, Seo GH, Lee H, Chen KJ, Wu WC, Hsiao MC, Wang NK. Maternal mosaicism in SSBP1 causing optic atrophy with retinal degeneration: implications for genetic counseling. Orphanet J Rare Dis 2023; 18:131. [PMID: 37259171 PMCID: PMC10233871 DOI: 10.1186/s13023-023-02748-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 05/18/2023] [Indexed: 06/02/2023] Open
Abstract
BACKGROUND Optic atrophy-13 with retinal and foveal abnormalities (OPA13) (MIM #165510) is a mitochondrial disease in which apparent bilateral optic atrophy is present and sometimes followed by retinal pigmentary changes or photoreceptors degeneration. OPA13 is caused by heterozygous mutation in the SSBP1 gene, associated with variable mitochondrial dysfunctions. RESULTS We have previously reported a 16-year-old Taiwanese male diagnosed with OPA13 and SSBP1 variant c.320G>A (p.Arg107Gln) was identified by whole exon sequence (WES). This variant was assumed to be de novo since his parents were clinically unaffected. However, WES and Sanger sequencing further revealed the proband's unaffected mother carrying the same SSBP1 variant with a 13% variant allele frequency (VAF) in her peripheral blood. That finding strongly indicates the maternal gonosomal mosaicism contributing to OPA13, which has not been reported before. CONCLUSIONS In summary, we described the first case of OPA13 caused by maternal gonosomal mosaicism in SSBP1. Parental mosaicism could be a serious issue in OPA13 diagnosis, and appropriate genetic counseling should be considered.
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Affiliation(s)
- Yin-Hsi Chang
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Eugene Yu-Chuan Kang
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Laura Liu
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Laura A Jenny
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Columbia University, 635 West 165th Street, New York, NY, 10032, USA
| | - Rin Khang
- Division of Medical Genetics, 3Billion Inc., Seoul, South Korea
| | - Go Hun Seo
- Division of Medical Genetics, 3Billion Inc., Seoul, South Korea
| | - Hane Lee
- Division of Medical Genetics, 3Billion Inc., Seoul, South Korea
| | - Kuan-Jen Chen
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Wei-Chi Wu
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Meng-Chang Hsiao
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Nan-Kai Wang
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Columbia University, 635 West 165th Street, New York, NY, 10032, USA.
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Chang YH, Kang EYC, Liu L, Jenny LA, Khang R, Seo GH, Lee H, Chen KJ, Wu WC, Hsiao MC, Wang NK. Maternal Mosaicism in SSBP1 Causing Optic Atrophy with Retinal Degeneration: Implications for Genetic Counseling. RESEARCH SQUARE 2023:rs.3.rs-2554402. [PMID: 36993412 PMCID: PMC10055506 DOI: 10.21203/rs.3.rs-2554402/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
Background: Optic atrophy-13 with retinal and foveal abnormalities (OPA13) (MIM #165510) is a mitochondrial disease in which apparent bilateral optic atrophy is present and sometimes followed by retinal pigmentary changes or photoreceptors degeneration. OPA13 is caused by heterozygous mutation in the SSBP1 gene, associated with variable mitochondrial dysfunctions. Results: We have previously reported a 16-year-old Taiwanese male diagnosed with OPA13 and SSBP1 variant c.320G>A (p.Arg107Gln) was identified by whole exon sequence (WES). This variant was assumed to be de novo since his parents were clinically unaffected. However, WES and Sanger sequencing further revealed the proband’s unaffected mother carrying the same SSBP1 variant with a 13% variant allele frequency (VAF) in her peripheral blood. That finding strongly indicates the maternal gonosomal mosaicism contributing to OPA13, which has not been reported before. Conclusions: In summary, we described the first case of OPA13 caused by maternal gonosomal mosaicism in SSBP1 . Parental mosaicism could be a serious issue in OPA13 diagnosis, and appropriate genetic counseling should be considered.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Meng-Chang Hsiao
- Columbia University Medical Center: Columbia University Irving Medical Center
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5
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Chang YH, Kang EYC, Liu PK, Levi SR, Wang HH, Tseng YJ, Seo GH, Lee H, Yeh LK, Chen KJ, Wu WC, Lai CC, Liu L, Wang NK. Photoreceptor Manifestations of Primary Mitochondrial Optic Nerve Disorders. Invest Ophthalmol Vis Sci 2022; 63:5. [PMID: 35506936 PMCID: PMC9078049 DOI: 10.1167/iovs.63.5.5] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Purpose To compare the manifestations of photoreceptors (PRs) in three hereditary optic neuropathies affected by primary mitochondrial dysfunction and discuss whether the retinal ganglion cells (RGCs) or the PRs are preferentially affected. Methods A retrospective analysis of patients with genetically confirmed diagnoses of optic neuropathies associated with mitochondrial dysfunction was performed. This cohort included Leber's hereditary optic neuropathy (LHON), autosomal dominant optic atrophy type 1 (OPA1), and optic atrophy type 13 (OPA13). Patient chart evaluations included clinical characteristics, best-corrected visual acuity (BCVA), fundus photography, spectral-domain optical coherence tomography (SD-OCT), electroretinogram (ERG), and visual evoked potential data. Results This analysis included seven patients with LHON, six with OPA1, and one with OPA13 from a tertiary medical center. Thirteen of the 14 individuals were male. The average BCVA at diagnosis was 20/285 and 20/500 in the right and left eyes, respectively. Five of the seven patients with LHON, and three of the six patients with OPA1 also showed a mild amplitude reduction or delayed latency on light-adapted ERG and 30-Hz flicker responses; however, SD-OCT imaging did not show correlated PR abnormalities. Notably, a 7-year follow-up of a patient with OPA13 revealed degeneration of RGCs prior to the degeneration of PRs. Follow-up data also demonstrated continuous loss of cone outer segment tips on SD-OCT imaging. Conclusions RGCs are, in general, affected by mitochondrial dysfunction, whereas variable PR dysfunction exists in patients with LHON and OPA1, especially with respect to the cone responses. Involvement of PRs is particularly evident in OPA13 after RGC degenerations.
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Affiliation(s)
- Yin-Hsi Chang
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Eugene Yu-Chuan Kang
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Pei-Kang Liu
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.,School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan.,Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Columbia University, New York, New York, United States
| | - Sarah R Levi
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Columbia University, New York, New York, United States
| | - Hung-Hsuan Wang
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Columbia University, New York, New York, United States
| | - Yun-Ju Tseng
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Columbia University, New York, New York, United States
| | - Go Hun Seo
- Division of Medical Genetics, 3billion, Inc., Seoul, South Korea
| | - Hane Lee
- Division of Medical Genetics, 3billion, Inc., Seoul, South Korea
| | - Lung-Kun Yeh
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Kuan-Jen Chen
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Wei-Chi Wu
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chi-Chun Lai
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Ophthalmology, Chang Gung Memorial Hospital, Keelung, Taiwan
| | - Laura Liu
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan.,School of Traditional Chinese Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Nan-Kai Wang
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Columbia University, New York, New York, United States
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6
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Li J, Du J, Li S, Wang X. Identification and Characterization of a Double-Stranded RNA Degrading Nuclease Influencing RNAi Efficiency in the Rice Leaf Folder Cnaphalocrocis medinalis. Int J Mol Sci 2022; 23:ijms23073961. [PMID: 35409320 PMCID: PMC8999895 DOI: 10.3390/ijms23073961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 03/27/2022] [Accepted: 03/30/2022] [Indexed: 02/06/2023] Open
Abstract
Rice leaf folder Cnaphalocrocis medinalis is one of the most serious pests of rice in rice-planting regions worldwide. DsRNA-degrading nucleases (dsRNases) are important factors in reducing the efficiency of RNA interference (RNAi) in different insects. In this study, a dsRNase gene from C. medinalis (CmdsRNase) was cloned and characterized. The CmdsRNase cDNA was 1395 bp in length, encoding 464 amino acids. The CmdsRNase zymoprotein contains a signal peptide and an endonuclease NS domain that comprises six active sites, three substrate-binding sites, and one Mg2+-binding site. The mature CmdsRNase forms a homodimer with a total of 16 α-helices and 20 β-pleated sheets. Homology and phylogenetic analyses revealed that CmdsRNase is closely related to dsRNase2 in Ostrinia nubilalis. Expression pattern analysis by droplet digital PCR indicated that the expression levels of CmdsRNase varied throughout the developmental stages of C. medinalis and in different adult tissues, with the highest expression levels in the fourth-instar larvae and the hemolymph. CmdsRNase can degrade dsRNA to reduce the efficiency of RNAi in C. medinalis. Co-silencing of CmCHS (chitin synthase from C. medinalis) and CmdsRNase affected significantly the growth and development of C. medinalis and thus improved RNAi efficacy, which increased by 27.17%. These findings will be helpful for green control of C. medinalis and other lepidopteran pests by RNAi.
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Roberts FL, Markby GR. New Insights into Molecular Mechanisms Mediating Adaptation to Exercise; A Review Focusing on Mitochondrial Biogenesis, Mitochondrial Function, Mitophagy and Autophagy. Cells 2021; 10:cells10102639. [PMID: 34685618 PMCID: PMC8533934 DOI: 10.3390/cells10102639] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 09/27/2021] [Accepted: 09/29/2021] [Indexed: 12/25/2022] Open
Abstract
Exercise itself is fundamental for good health, and when practiced regularly confers a myriad of metabolic benefits in a range of tissues. These benefits are mediated by a range of adaptive responses in a coordinated, multi-organ manner. The continued understanding of the molecular mechanisms of action which confer beneficial effects of exercise on the body will identify more specific pathways which can be manipulated by therapeutic intervention in order to prevent or treat various metabolism-associated diseases. This is particularly important as exercise is not an available option to all and so novel methods must be identified to confer the beneficial effects of exercise in a therapeutic manner. This review will focus on key emerging molecular mechanisms of mitochondrial biogenesis, autophagy and mitophagy in selected, highly metabolic tissues, describing their regulation and contribution to beneficial adaptations to exercise.
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Kron NS, Fieber LA. Co-expression analysis identifies neuro-inflammation as a driver of sensory neuron aging in Aplysia californica. PLoS One 2021; 16:e0252647. [PMID: 34116561 PMCID: PMC8195618 DOI: 10.1371/journal.pone.0252647] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 05/20/2021] [Indexed: 01/08/2023] Open
Abstract
Aging of the nervous system is typified by depressed metabolism, compromised proteostasis, and increased inflammation that results in cognitive impairment. Differential expression analysis is a popular technique for exploring the molecular underpinnings of neural aging, but technical drawbacks of the methodology often obscure larger expression patterns. Co-expression analysis offers a robust alternative that allows for identification of networks of genes and their putative central regulators. In an effort to expand upon previous work exploring neural aging in the marine model Aplysia californica, we used weighted gene correlation network analysis to identify co-expression networks in a targeted set of aging sensory neurons in these animals. We identified twelve modules, six of which were strongly positively or negatively associated with aging. Kyoto Encyclopedia of Genes analysis and investigation of central module transcripts identified signatures of metabolic impairment, increased reactive oxygen species, compromised proteostasis, disrupted signaling, and increased inflammation. Although modules with immune character were identified, there was no correlation between genes in Aplysia that increased in expression with aging and the orthologous genes in oyster displaying long-term increases in expression after a virus-like challenge. This suggests anti-viral response is not a driver of Aplysia sensory neuron aging.
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Affiliation(s)
- N. S. Kron
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States of America
| | - L. A. Fieber
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States of America
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9
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Wang W, Li J, Tan J, Wang M, Yang J, Zhang ZM, Li C, Basnakian AG, Tang HW, Perrimon N, Zhou Q. Endonuclease G promotes autophagy by suppressing mTOR signaling and activating the DNA damage response. Nat Commun 2021; 12:476. [PMID: 33473107 PMCID: PMC7817833 DOI: 10.1038/s41467-020-20780-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 12/17/2020] [Indexed: 12/13/2022] Open
Abstract
Endonuclease G (ENDOG), a mitochondrial nuclease, is known to participate in many cellular processes, including apoptosis and paternal mitochondrial elimination, while its role in autophagy remains unclear. Here, we report that ENDOG released from mitochondria promotes autophagy during starvation, which we find to be evolutionally conserved across species by performing experiments in human cell lines, mice, Drosophila and C. elegans. Under starvation, Glycogen synthase kinase 3 beta-mediated phosphorylation of ENDOG at Thr-128 and Ser-288 enhances its interaction with 14-3-3γ, which leads to the release of Tuberin (TSC2) and Phosphatidylinositol 3-kinase catalytic subunit type 3 (Vps34) from 14-3-3γ, followed by mTOR pathway suppression and autophagy initiation. Alternatively, ENDOG activates DNA damage response and triggers autophagy through its endonuclease activity. Our results demonstrate that ENDOG is a crucial regulator of autophagy, manifested by phosphorylation-mediated interaction with 14-3-3γ, and its endonuclease activity-mediated DNA damage response.
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Affiliation(s)
- Wenjun Wang
- The First Affiliated Hospital, Jinan University, Guangzhou, Guangdong, 510632, China.,Zhuhai Institute of Translational Medicine Zhuhai People's Hospital Affiliated with Jinan University, Jinan University, Zhuhai, Guangdong, 519000, China.,The Biomedical Translational Research Institute, Faculty of Medical Science, Jinan University, Guangzhou, Guangdong, 510632, China
| | - Jianshuang Li
- Zhuhai Institute of Translational Medicine Zhuhai People's Hospital Affiliated with Jinan University, Jinan University, Zhuhai, Guangdong, 519000, China.,The Biomedical Translational Research Institute, Faculty of Medical Science, Jinan University, Guangzhou, Guangdong, 510632, China
| | - Junyang Tan
- The Biomedical Translational Research Institute, Faculty of Medical Science, Jinan University, Guangzhou, Guangdong, 510632, China
| | - Miaomiao Wang
- The Biomedical Translational Research Institute, Faculty of Medical Science, Jinan University, Guangzhou, Guangdong, 510632, China
| | - Jing Yang
- The Biomedical Translational Research Institute, Faculty of Medical Science, Jinan University, Guangzhou, Guangdong, 510632, China
| | - Zhi-Min Zhang
- International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Chinese Ministry of Education (MOE), College of Pharmacy, Jinan University, Guangzhou, Guangdong, 510632, China
| | - Chuanzhou Li
- Department of Medical Genetics, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Alexei G Basnakian
- Department of Pharmacology & Toxicology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | - Hong-Wen Tang
- Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, 8 College Road, Singapore, 169857, Singapore.,Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Norbert Perrimon
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA.,Howard Hughes Medical Institute, Boston, MA, 02115, USA
| | - Qinghua Zhou
- The First Affiliated Hospital, Jinan University, Guangzhou, Guangdong, 510632, China. .,Zhuhai Institute of Translational Medicine Zhuhai People's Hospital Affiliated with Jinan University, Jinan University, Zhuhai, Guangdong, 519000, China. .,The Biomedical Translational Research Institute, Faculty of Medical Science, Jinan University, Guangzhou, Guangdong, 510632, China.
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10
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Jia H, Mo W, Hong M, Jiang S, Zhang YY, He D, Yu D, Shi Y, Cao J, Xu X, Zhang S. Interferon-α inducible protein 6 (IFI6) confers protection against ionizing radiation in skin cells. J Dermatol Sci 2020; 100:139-147. [PMID: 33059972 DOI: 10.1016/j.jdermsci.2020.09.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 09/03/2020] [Accepted: 09/13/2020] [Indexed: 01/08/2023]
Abstract
BACKGROUND Radiation-induced skin injury is one of the main adverse effects and a dose-limiting factor of radiotherapy without feasible treatment. The underlying mechanism of this disease is still limited. OBJECTIVE To investigate the potential molecular pathways and mechanisms of radiation-induced skin injury. METHODS mRNA expression profiles were determined by Affymetrix Human HTA2.0 microarray.IFI6 overexpression and knockdown were mediated by lentivirus. The functional changes of skin cells were measured by flow cytometry, ROS probe and Edu probe. Protein distribution was detected by immunofluorescence experiment, and IFI6-interacting proteins were detected by immunoprecipitation (IP) combined with mass spectrometry. The global gene changes in IFI6-overexpressed skin cells after irradiation were detected by RNA-seq. RESULTS mRNA expression profiling showed 50 upregulated and 13 down regulated genes and interferon alpha inducible protein 6 (IFI6) was top upregulated. Overexpression of IFI6 promoted cell proliferation and reduced cell apoptosis as well as ROS production following radiation, and conversely, increased the radiosensitivity of HaCaT and human skin fibroblast (WS1). IFI6 was translocated into nucleus in irradiated skin cells and the interacting relationship with mitochondrial single-stranded DNA-binding protein 1 (SSBP1), which could enhance the transcriptional activity of heat shock transcription factor 1 (HSF1).IFI6 augmented HSF1 activity following radiation in HaCaT and WS1 cells. RNA-seq analysis showed IFI6 modulated virus infection and cellular response to stress pathways, which may help to further explore how IFI6 regulate the transcriptional activity of HSF1. CONCLUSION This study reveals that IFI6 is induced by ionizing radiation and confers radioprotection in skin cells.
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Affiliation(s)
- Huimin Jia
- State Key Lab of Radiation Medicine and Protection, Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, China
| | - Wei Mo
- State Key Lab of Radiation Medicine and Protection, Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, China
| | - Min Hong
- State Key Lab of Radiation Medicine and Protection, Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, China
| | - Sheng Jiang
- Second Affiliated Hospital of Chengdu Medical College, China National Nuclear Corporation 416 Hospital, Chengdu, China
| | - Yuan-Yuan Zhang
- West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, China
| | - Dan He
- Second Affiliated Hospital of Chengdu Medical College, China National Nuclear Corporation 416 Hospital, Chengdu, China
| | - Daojiang Yu
- Second Affiliated Hospital of Chengdu Medical College, China National Nuclear Corporation 416 Hospital, Chengdu, China
| | - Yuhong Shi
- Second Affiliated Hospital of Chengdu Medical College, China National Nuclear Corporation 416 Hospital, Chengdu, China
| | - Jianping Cao
- State Key Lab of Radiation Medicine and Protection, Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, China
| | - Xiaohui Xu
- Department of General Surgery, The First People's Hospital of Taicang, Taicang Affiliated Hospital of Soochow University, Taicang, China.
| | - Shuyu Zhang
- Second Affiliated Hospital of Chengdu Medical College, China National Nuclear Corporation 416 Hospital, Chengdu, China; West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, China.
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11
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Mitochondrial dysfunction in the fetoplacental unit in gestational diabetes mellitus. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165948. [PMID: 32866635 DOI: 10.1016/j.bbadis.2020.165948] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/17/2020] [Accepted: 08/20/2020] [Indexed: 12/12/2022]
Abstract
Gestational diabetes mellitus (GDM) is a disease of pregnancy that is associated with d-glucose intolerance and foeto-placental vascular dysfunction. GMD causes mitochondrial dysfunction in the placental endothelium and trophoblast. Additionally, GDM is associated with reduced placental oxidative phosphorylation due to diminished activity of the mitochondrial F0F1-ATP synthase (complex V). This phenomenon may result from a higher generation of reactive superoxide anion and nitric oxide. Placental mitochondrial biogenesis and mitophagy work in concert to maintain cell homeostasis and are vital mechanisms securing the efficient generation of ATP, whose demand is higher in pregnancy, ensuring foetal growth and development. Additional factors disturbing placental ATP synthase activity in GDM include pre-gestational maternal obesity or overweight, intracellular pH, miRNAs, fatty acid oxidation, and foetal (and 'placental') sex. GDM is also associated with maternal and foetal hyperinsulinaemia, altered circulating levels of adiponectin and leptin, and the accumulation of extracellular adenosine. Here, we reviewed the potential interplay between these molecules or metabolic conditions on the mechanisms of mitochondrial dysfunction in the foeto-placental unit in GDM pregnancies.
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12
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Del Dotto V, Ullah F, Di Meo I, Magini P, Gusic M, Maresca A, Caporali L, Palombo F, Tagliavini F, Baugh EH, Macao B, Szilagyi Z, Peron C, Gustafson MA, Khan K, La Morgia C, Barboni P, Carbonelli M, Valentino ML, Liguori R, Shashi V, Sullivan J, Nagaraj S, El-Dairi M, Iannaccone A, Cutcutache I, Bertini E, Carrozzo R, Emma F, Diomedi-Camassei F, Zanna C, Armstrong M, Page M, Stong N, Boesch S, Kopajtich R, Wortmann S, Sperl W, Davis EE, Copeland WC, Seri M, Falkenberg M, Prokisch H, Katsanis N, Tiranti V, Pippucci T, Carelli V. SSBP1 mutations cause mtDNA depletion underlying a complex optic atrophy disorder. J Clin Invest 2020; 130:108-125. [PMID: 31550240 DOI: 10.1172/jci128514] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 09/19/2019] [Indexed: 01/07/2023] Open
Abstract
Inherited optic neuropathies include complex phenotypes, mostly driven by mitochondrial dysfunction. We report an optic atrophy spectrum disorder, including retinal macular dystrophy and kidney insufficiency leading to transplantation, associated with mitochondrial DNA (mtDNA) depletion without accumulation of multiple deletions. By whole-exome sequencing, we identified mutations affecting the mitochondrial single-strand binding protein (SSBP1) in 4 families with dominant and 1 with recessive inheritance. We show that SSBP1 mutations in patient-derived fibroblasts variably affect the amount of SSBP1 protein and alter multimer formation, but not the binding to ssDNA. SSBP1 mutations impaired mtDNA, nucleoids, and 7S-DNA amounts as well as mtDNA replication, affecting replisome machinery. The variable mtDNA depletion in cells was reflected in severity of mitochondrial dysfunction, including respiratory efficiency, OXPHOS subunits, and complex amount and assembly. mtDNA depletion and cytochrome c oxidase-negative cells were found ex vivo in biopsies of affected tissues, such as kidney and skeletal muscle. Reduced efficiency of mtDNA replication was also reproduced in vitro, confirming the pathogenic mechanism. Furthermore, ssbp1 suppression in zebrafish induced signs of nephropathy and reduced optic nerve size, the latter phenotype complemented by WT mRNA but not by SSBP1 mutant transcripts. This previously unrecognized disease of mtDNA maintenance implicates SSBP1 mutations as a cause of human pathology.
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Affiliation(s)
- Valentina Del Dotto
- Unit of Neurology, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Farid Ullah
- Center for Human Disease Modeling, Duke University, Durham, North Carolina, USA.,Human Molecular Genetics Laboratory, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan.,Pakistan Institute of Engineering and Applied Sciences (PIEAS), Faisalabad, Pakistan
| | - Ivano Di Meo
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico C. Besta, Milan, Italy
| | - Pamela Magini
- Medical Genetics Unit, Sant'Orsola-Malpighi University Hospital, Bologna, Italy
| | - Mirjana Gusic
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany.,Institute of Human Genetics, Technische Universität München, Munich, Germany
| | - Alessandra Maresca
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Italy
| | - Leonardo Caporali
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Italy
| | - Flavia Palombo
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Italy
| | - Francesca Tagliavini
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Italy
| | - Evan Harris Baugh
- Institute for Genomic Medicine, Columbia University, New York, New York, USA
| | - Bertil Macao
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Zsolt Szilagyi
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Camille Peron
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico C. Besta, Milan, Italy
| | - Margaret A Gustafson
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Kamal Khan
- Center for Human Disease Modeling, Duke University, Durham, North Carolina, USA.,Human Molecular Genetics Laboratory, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan.,Pakistan Institute of Engineering and Applied Sciences (PIEAS), Faisalabad, Pakistan
| | - Chiara La Morgia
- Unit of Neurology, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy.,IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Italy
| | - Piero Barboni
- Department of Ophthalmology, Studio Oculistico d'Azeglio, Bologna, Italy
| | - Michele Carbonelli
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Italy
| | - Maria Lucia Valentino
- Unit of Neurology, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy.,IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Italy
| | - Rocco Liguori
- Unit of Neurology, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy.,IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Italy
| | | | | | - Shashi Nagaraj
- Division of Nephrology, Department of Pediatrics, Duke University School of Medicine, Durham, North Carolina, USA
| | | | - Alessandro Iannaccone
- Center for Retinal Degenerations and Ophthalmic Genetic Diseases and Visual Function Diagnostic Laboratory, Duke Eye Center, Duke University School of Medicine, Durham, North Carolina, USA
| | | | - Enrico Bertini
- Unit of Muscular and Neurodegenerative Diseases, Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Rosalba Carrozzo
- Unit of Muscular and Neurodegenerative Diseases, Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Francesco Emma
- Division of Nephrology, Department of Pediatric Subspecialties, Bambino Gesù Children's Hospital, Rome, Italy
| | | | - Claudia Zanna
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Bologna, Italy
| | | | - Matthew Page
- Translational Medicine, UCB Pharma, Slough, United Kingdom
| | - Nicholas Stong
- Institute for Genomic Medicine, Columbia University, New York, New York, USA
| | - Sylvia Boesch
- Department of Neurology, Medical University Innsbruck, Innsbruck, Austria
| | - Robert Kopajtich
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany.,Institute of Human Genetics, Technische Universität München, Munich, Germany
| | - Saskia Wortmann
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany.,Institute of Human Genetics, Technische Universität München, Munich, Germany.,Department of Pediatrics, Salzburger Landeskliniken and Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Wolfgang Sperl
- Department of Pediatrics, Salzburger Landeskliniken and Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Erica E Davis
- Center for Human Disease Modeling, Duke University, Durham, North Carolina, USA
| | - William C Copeland
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Marco Seri
- Medical Genetics Unit, Sant'Orsola-Malpighi University Hospital, Bologna, Italy.,Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Maria Falkenberg
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Holger Prokisch
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany.,Institute of Human Genetics, Technische Universität München, Munich, Germany
| | - Nicholas Katsanis
- Center for Human Disease Modeling, Duke University, Durham, North Carolina, USA.,Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA.,Departments of Pediatrics and Cellular and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Valeria Tiranti
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico C. Besta, Milan, Italy
| | - Tommaso Pippucci
- Medical Genetics Unit, Sant'Orsola-Malpighi University Hospital, Bologna, Italy
| | - Valerio Carelli
- Unit of Neurology, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy.,IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Italy
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13
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High expression of oxidative phosphorylation genes predicts improved survival in squamous cell carcinomas of the head and neck and lung. Sci Rep 2020; 10:6380. [PMID: 32286489 PMCID: PMC7156383 DOI: 10.1038/s41598-020-63448-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 03/31/2020] [Indexed: 01/03/2023] Open
Abstract
Mitochondrial activity is a critical component of tumor metabolism, with profound implications for tumorigenesis and treatment response. We analyzed clinical, genomic and expression data from patients with oral cavity squamous cell carcinoma (OCSCC) in order to map metabologenomic events which may correlate with clinical outcomes and identified nuclear genes involved in oxidative phosphorylation and glycolysis (OXPHOG) as a critical predictor of patient survival. This correlation was validated in a secondary unrelated set of lung squamous cell carcinoma (LUSC) and was shown to be driven largely by over-expression of nuclear encoded components of the mitochondrial electron transport chain (ETC) coordinated with an increase in tumor mitochondrial DNA copy number and a strong threshold effect on patient survival. OCSCC and LUSC patients with a favorable OXPHOG signature demonstrated a dramatic (>2fold) improvement in survival compared to their counterparts. Differential OXPHOG expression correlated with varying tumor immune infiltrates suggesting that the interaction between tumor metabolic activity and tumor associated immunocytes may be a critical driver of improved clinical outcomes in this patient subset. These data provide strong support for studies aimed at mechanistically characterizing the interaction between tumor mitochondrial activity and the tumor immune microenvironment.
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14
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Jurkute N, Leu C, Pogoda HM, Arno G, Robson AG, Nürnberg G, Altmüller J, Thiele H, Motameny S, Toliat MR, Powell K, Höhne W, Michaelides M, Webster AR, Moore AT, Hammerschmidt M, Nürnberg P, Yu-Wai-Man P, Votruba M. SSBP1 mutations in dominant optic atrophy with variable retinal degeneration. Ann Neurol 2019; 86:368-383. [PMID: 31298765 DOI: 10.1002/ana.25550] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 07/10/2019] [Accepted: 07/10/2019] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Autosomal dominant optic atrophy (ADOA) starts in early childhood with loss of visual acuity and color vision deficits. OPA1 mutations are responsible for the majority of cases, but in a portion of patients with a clinical diagnosis of ADOA, the cause remains unknown. This study aimed to identify novel ADOA-associated genes and explore their causality. METHODS Linkage analysis and sequencing were performed in multigeneration families and unrelated patients to identify disease-causing variants. Functional consequences were investigated in silico and confirmed experimentally using the zebrafish model. RESULTS We defined a new ADOA locus on 7q33-q35 and identified 3 different missense variants in SSBP1 (NM_001256510.1; c.113G>A [p.(Arg38Gln)], c.320G>A [p.(Arg107Gln)] and c.422G>A [p.(Ser141Asn)]) in affected individuals from 2 families and 2 singletons with ADOA and variable retinal degeneration. The mutated arginine residues are part of a basic patch that is essential for single-strand DNA binding. The loss of a positive charge at these positions is very likely to lower the affinity of SSBP1 for single-strand DNA. Antisense-mediated knockdown of endogenous ssbp1 messenger RNA (mRNA) in zebrafish resulted in compromised differentiation of retinal ganglion cells. A similar effect was achieved when mutated mRNAs were administered. These findings point toward an essential role of ssbp1 in retinal development and the dominant-negative nature of the identified human variants, which is consistent with the segregation pattern observed in 2 multigeneration families studied. INTERPRETATION SSBP1 is an essential protein for mitochondrial DNA replication and maintenance. Our data have established pathogenic variants in SSBP1 as a cause of ADOA and variable retinal degeneration. ANN NEUROL 2019;86:368-383.
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Affiliation(s)
- Neringa Jurkute
- Moorfields Eye Hospital National Health Service Foundation Trust, London, United Kingdom.,University College London Institute of Ophthalmology, University College London, London, United Kingdom
| | - Costin Leu
- Cologne Center for Genomics, University of Cologne, Cologne, Germany.,Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH.,Genomic Medicine Institute, Lerner Research Institute Cleveland Clinic, Cleveland, OH.,Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA
| | - Hans-Martin Pogoda
- Institute for Zoology, Developmental Biology Unit, University of Cologne, Cologne, Germany
| | - Gavin Arno
- Moorfields Eye Hospital National Health Service Foundation Trust, London, United Kingdom.,University College London Institute of Ophthalmology, University College London, London, United Kingdom
| | - Anthony G Robson
- Moorfields Eye Hospital National Health Service Foundation Trust, London, United Kingdom.,University College London Institute of Ophthalmology, University College London, London, United Kingdom
| | - Gudrun Nürnberg
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Janine Altmüller
- Cologne Center for Genomics, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Holger Thiele
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Susanne Motameny
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | | | - Kate Powell
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - Wolfgang Höhne
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Michel Michaelides
- Moorfields Eye Hospital National Health Service Foundation Trust, London, United Kingdom.,University College London Institute of Ophthalmology, University College London, London, United Kingdom
| | - Andrew R Webster
- Moorfields Eye Hospital National Health Service Foundation Trust, London, United Kingdom.,University College London Institute of Ophthalmology, University College London, London, United Kingdom
| | - Anthony T Moore
- Moorfields Eye Hospital National Health Service Foundation Trust, London, United Kingdom.,University College London Institute of Ophthalmology, University College London, London, United Kingdom.,Department of Ophthalmology, University of California, San Francisco, San Francisco, CA
| | - Matthias Hammerschmidt
- Institute for Zoology, Developmental Biology Unit, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Peter Nürnberg
- Cologne Center for Genomics, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Patrick Yu-Wai-Man
- Moorfields Eye Hospital National Health Service Foundation Trust, London, United Kingdom.,University College London Institute of Ophthalmology, University College London, London, United Kingdom.,Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, United Kingdom.,Cambridge Centre for Brain Repair and Medical Research Council Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Marcela Votruba
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom.,Cardiff Eye Unit, University Hospital Wales, Cardiff, United Kingdom
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15
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Abstract
Obesity is a medical condition that impacts on all levels of society and causes numerous comorbidities, such as diabetes, cardiovascular disease, and cancer. We assessed the suitability of targeting enolase, a glycolysis pathway enzyme with multiple, secondary functions in cells, to treat obesity. Treating adipocytes with ENOblock, a novel modulator of these secondary ‘moonlighting’ functions of enolase, suppressed the adipogenic program and induced mitochondrial uncoupling. Obese animals treated with ENOblock showed a reduction in body weight and increased core body temperature. Metabolic and inflammatory parameters were improved in the liver, adipose tissue and hippocampus. The mechanism of ENOblock was identified as transcriptional repression of master regulators of lipid homeostasis (Srebp-1a and Srebp-1c), gluconeogenesis (Pck-1) and inflammation (Tnf-α and Il-6). ENOblock treatment also reduced body weight gain, lowered cumulative food intake and increased fecal lipid content in mice fed a high fat diet. Our results support the further drug development of ENOblock as a therapeutic for obesity and suggest enolase as a new target for this disorder.
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16
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Jin W, Qazi TJ, Quan Z, Li N, Qing H. Dysregulation of Transcription Factors: A Key Culprit Behind Neurodegenerative Disorders. Neuroscientist 2018; 25:548-565. [PMID: 30484370 DOI: 10.1177/1073858418811787] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Neurodegenerative diseases (NDs) are considered heterogeneous disorders characterized by progressive pathological changes in neuronal systems. Transcription factors are protein molecules that are important in regulating the expression of genes. Although the clinical manifestations of NDs vary, the pathological processes appear similar with regard to neuroinflammation, oxidative stress, and proteostasis, to which, as numerous studies have discovered, transcription factors are closely linked. In this review, we summarized and reviewed the roles of transcription factors in NDs, and then we elucidated their functions during pathological processes, and finally we discussed their therapeutic values in NDs.
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Affiliation(s)
- Wei Jin
- Beijing Key Laboratory of Separation and Analysis in Biomedical and Pharmaceuticals, Department of Biomedical Engineering, School of Life Science, Beijing Institute of Technology, Haidian District, Beijing, China
| | - Talal Jamil Qazi
- Beijing Key Laboratory of Separation and Analysis in Biomedical and Pharmaceuticals, Department of Biomedical Engineering, School of Life Science, Beijing Institute of Technology, Haidian District, Beijing, China
| | - Zhenzhen Quan
- Beijing Key Laboratory of Separation and Analysis in Biomedical and Pharmaceuticals, Department of Biomedical Engineering, School of Life Science, Beijing Institute of Technology, Haidian District, Beijing, China
| | - Nuomin Li
- Beijing Key Laboratory of Separation and Analysis in Biomedical and Pharmaceuticals, Department of Biomedical Engineering, School of Life Science, Beijing Institute of Technology, Haidian District, Beijing, China
| | - Hong Qing
- Beijing Key Laboratory of Separation and Analysis in Biomedical and Pharmaceuticals, Department of Biomedical Engineering, School of Life Science, Beijing Institute of Technology, Haidian District, Beijing, China
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17
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Barshad G, Marom S, Cohen T, Mishmar D. Mitochondrial DNA Transcription and Its Regulation: An Evolutionary Perspective. Trends Genet 2018; 34:682-692. [DOI: 10.1016/j.tig.2018.05.009] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 05/19/2018] [Accepted: 05/31/2018] [Indexed: 12/15/2022]
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18
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Evidence for Compartmentalized Axonal Mitochondrial Biogenesis: Mitochondrial DNA Replication Increases in Distal Axons As an Early Response to Parkinson's Disease-Relevant Stress. J Neurosci 2018; 38:7505-7515. [PMID: 30030401 DOI: 10.1523/jneurosci.0541-18.2018] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 06/19/2018] [Accepted: 07/07/2018] [Indexed: 12/18/2022] Open
Abstract
Dysregulation of mitochondrial biogenesis is implicated in the pathogenesis of neurodegenerative diseases such as Parkinson's disease (PD). However, it is not clear how mitochondrial biogenesis is regulated in neurons, with their unique compartmentalized anatomy and energetic demands. This is particularly relevant in PD because selectively vulnerable neurons feature long, highly arborized axons where degeneration initiates. We previously found that exposure of neurons to chronic, sublethal doses of rotenone, a complex I inhibitor linked to PD, causes early increases in mitochondrial density specifically in distal axons, suggesting possible upregulation of mitochondrial biogenesis within axons. Here, we directly evaluated for evidence of mitochondrial biogenesis in distal axons and examined whether PD-relevant stress causes compartmentalized alterations. Using BrdU labeling and imaging to quantify replicating mitochondrial DNA (mtDNA) in primary rat neurons (pooled from both sexes), we provide evidence of mtDNA replication in axons along with cell bodies and proximal dendrites. We found that exposure to chronic, sublethal rotenone increases mtDNA replication first in neurites and later extending to cell bodies, complementing our mitochondrial density data. Further, isolating axons from cell bodies and dendrites, we discovered that rotenone exposure upregulates mtDNA replication in distal axons. Utilizing superresolution stimulated emission depletion (STED) imaging, we identified mtDNA replication at sites of mitochondrial-endoplasmic reticulum contacts in axons. Our evidence suggests that mitochondrial biogenesis occurs not only in cell bodies, but also in distal axons, and is altered under PD-relevant stress conditions in an anatomically compartmentalized manner. We hypothesize that this contributes to vulnerability in neurodegenerative diseases.SIGNIFICANCE STATEMENT Mitochondrial biogenesis is crucial for maintaining mitochondrial and cellular health and has been linked to neurodegenerative disease pathogenesis. However, regulation of this process is poorly understood in CNS neurons, which rely on mitochondrial function for survival. Our findings offer fundamental insight into these regulatory mechanisms by demonstrating that replication of mitochondrial DNA, an essential precursor for biogenesis, can occur in distal regions of CNS neuron axons independent of the soma. Further, this process is upregulated specifically in axons as an early response to neurodegeneration-relevant stress. This is the first demonstration of the compartmentalized regulation of CNS neuronal mitochondrial biogenesis in response to stress and may prove a useful target in development of therapeutic strategies for neurodegenerative disease.
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19
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Wiehe RS, Gole B, Chatre L, Walther P, Calzia E, Ricchetti M, Wiesmüller L. Endonuclease G promotes mitochondrial genome cleavage and replication. Oncotarget 2018; 9:18309-18326. [PMID: 29719607 PMCID: PMC5915074 DOI: 10.18632/oncotarget.24822] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 03/12/2018] [Indexed: 12/26/2022] Open
Abstract
Endonuclease G (EndoG) is a nuclear-encoded endonuclease, mostly localised in mitochondria. In the nucleus EndoG participates in site-specific cleavage during replication stress and genome-wide DNA degradation during apoptosis. However, the impact of EndoG on mitochondrial DNA (mtDNA) metabolism is poorly understood. Here, we investigated whether EndoG is involved in the regulation of mtDNA replication and removal of aberrant copies. We applied the single-cell mitochondrial Transcription and Replication Imaging Protocol (mTRIP) and PCR-based strategies on human cells after knockdown/knockout and re-expression of EndoG. Our analysis revealed that EndoG stimulates both mtDNA replication initiation and mtDNA depletion, the two events being interlinked and dependent on EndoG's nuclease activity. Stimulation of mtDNA replication by EndoG was independent of 7S DNA processing at the replication origin. Importantly, both mtDNA-directed activities of EndoG were promoted by oxidative stress. Inhibition of base excision repair (BER) that repairs oxidative stress-induced DNA damage unveiled a pronounced effect of EndoG on mtDNA removal, reminiscent of recently discovered links between EndoG and BER in the nucleus. Altogether with the downstream effects on mitochondrial transcription, protein expression, redox status and morphology, this study demonstrates that removal of damaged mtDNA by EndoG and compensatory replication play a critical role in mitochondria homeostasis.
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Affiliation(s)
| | - Boris Gole
- Department of Obstetrics and Gynecology, Ulm University, Ulm, 89075, Germany
- Present address: Centre for Human Molecular Genetics and Pharmacogenomics, Medical Faculty, University of Maribor, Maribor, SI-2000, Slovenia
| | - Laurent Chatre
- Department of Developmental and Stem Cell Biology, Institute Pasteur, Stem Cells and Development, 75724 Cedex 15, Paris, France
- Team Stability of Nuclear and Mitochondrial DNA, Unit of Stem Cells and Development, CNRS UMR 3738, 75724 Cedex 15, Paris, France
| | - Paul Walther
- Central Facility for Electron Microscopy, Ulm University, Ulm, 89081, Germany
| | - Enrico Calzia
- Institute of Anesthesiological Pathophysiology and Process Engineering, Ulm University Hospital, Ulm, 89081, Germany
| | - Miria Ricchetti
- Department of Developmental and Stem Cell Biology, Institute Pasteur, Stem Cells and Development, 75724 Cedex 15, Paris, France
- Team Stability of Nuclear and Mitochondrial DNA, Unit of Stem Cells and Development, CNRS UMR 3738, 75724 Cedex 15, Paris, France
| | - Lisa Wiesmüller
- Department of Obstetrics and Gynecology, Ulm University, Ulm, 89075, Germany
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20
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Yoo NJ, Jeong EG, Kim MS, Ahn CH, Kim SS, Lee SH. Increased Expression of Endonuclease G in Gastric and Colorectal Carcinomas. TUMORI JOURNAL 2018; 94:351-5. [DOI: 10.1177/030089160809400311] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Aims Endonuclease G (EndoG) is a mitochondrial protein that plays a role in DNA fragmentation during apoptosis. In addition, EndoG plays a role in cell proliferation and survival. It may be important to identify EndoG protein expression to predict its function in human cancers. The aim of this study was to explore whether alteration of EndoG expression might be a characteristic of colorectal or gastric carcinoma. Methods We investigated EndoG protein expression in 103 colorectal and 60 gastric carcinoma tissues by immunohistochemistry using a tissue microarray approach. Results Expression of EndoG was detected in 72 (70%) of the colorectal carcinomas and 41 (68%) of the gastric carcinomas in cytoplasm. By contrast, normal mucosal cells of both stomach and colon tissues showed no or very weak expression of EndoG. There was no significant association of EndoG expression with clinocopathological characteristics, including invasion, metastasis and stage. Conclusion Our data indicate that EndoG inactivation by loss of expression may not occur in colorectal and gastric cancers. Rather, increased expression of EndoG in colorectal and gastric cancer cells compared to their normal mucosal epithelial counterparts suggests that neo-expression of EndoG may play a role in both colorectal and gastric tumorigenesis.
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Affiliation(s)
- Nam Jin Yoo
- Departments of Pathology, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Eun Goo Jeong
- Departments of Pathology, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Min Sung Kim
- Departments of Pathology, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Chang Hyeok Ahn
- Departments of General Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Sung Soo Kim
- Departments of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Sug Hyung Lee
- Departments of Pathology, College of Medicine, The Catholic University of Korea, Seoul, Korea
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21
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Augustyniak J, Lenart J, Zychowicz M, Stepien PP, Buzanska L. Mitochondrial biogenesis and neural differentiation of human iPSC is modulated by idebenone in a developmental stage-dependent manner. Biogerontology 2017. [PMID: 28643190 PMCID: PMC5514205 DOI: 10.1007/s10522-017-9718-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Idebenone, the synthetic analog of coenzyme Q10 can improve electron transport in mitochondria. Therefore, it is used in the treatment of Alzheimer’s disease and other cognitive impairments. However, the mechanism of its action on neurodevelopment is still to be elucidated. Here we demonstrate that the cellular response of human induced pluripotent stem cells (hiPSC) to idebenone depends on the stage of neural differentiation. When: neural stem cells (NSC), early neural progenitors (eNP) and advanced neural progenitors (NP) have been studied a significant stimulation of mitochondrial biogenesis was observed only at the eNP stage of development. This coexists with the enhancement of cell viability and increase in total cell number. In addition, we report novel idebenone properties in a possible regulation of neural stem cells fate decision: only eNP stage responded with up-regulation of both neuronal (MAP2), astrocytic (GFAP) markers, while at NSC and NP stages significant down-regulation of MAP2 expression was observed, promoting astrocyte differentiation. Thus, idebenone targets specific stages of hiPSC differentiation and may influence the neural stem cell fate decision.
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Affiliation(s)
- J Augustyniak
- Stem Cell Bioengineering Unit, Mossakowski Medical Research Centre Polish Academy of Sciences, Warsaw, Poland
| | - J Lenart
- Department of Neurochemistry, Mossakowski Medical Research Centre Polish Academy of Sciences, Warsaw, Poland
| | - M Zychowicz
- Stem Cell Bioengineering Unit, Mossakowski Medical Research Centre Polish Academy of Sciences, Warsaw, Poland
| | - P P Stepien
- Department of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland.,Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.,Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - L Buzanska
- Stem Cell Bioengineering Unit, Mossakowski Medical Research Centre Polish Academy of Sciences, Warsaw, Poland.
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22
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Chen W, Yi L, Feng S, Liu X, Asim M, Zhou Y, Lan J, Jiang S, Tu J, Lin L. Transcriptomic profiles of striped snakehead fish cells (SSN-1) infected with red-spotted grouper nervous necrosis virus (RGNNV) with an emphasis on apoptosis pathway. FISH & SHELLFISH IMMUNOLOGY 2017; 60:346-354. [PMID: 27914997 DOI: 10.1016/j.fsi.2016.11.059] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 11/13/2016] [Accepted: 11/29/2016] [Indexed: 05/07/2023]
Abstract
Nervous necrosis virus (NNV), the causative agent of viral nervous necrosis (VNN) disease, has caused mass mortality of cultured marine and freshwater fish worldwide, resulting in enormous economic losses in the aquaculture industry. However, the molecular mechanisms underlying the pathogenicity of NNV are still poorly understood. In this study, the transcriptomic profiles of striped snakehead fish (Channa striatus) cells (SSN-1) infected with red-spotted grouper NNV (RGNNV) were investigated using deep RNA sequencing technique. From 254,955,234 raw reads, a total of 253,338,544 clean reads were obtained and they were assembled into 93,372 unigenes. Differentially expressed genes (DEGs) were identified from RGNNV-infected or mock-infected SSN-1 cells, including 1184 up-regulated and 1456 down-regulated genes at 3 h (h) post of infection (poi), and 1138 up-regulated and 2073 down-regulated genes at 24 h poi, respectively. These DEGs were involved in many pathways related to viral pathogenesis, including retinoic acid-inducible gene I (RIG-I) like receptors pathway, apoptosis pathway, oxidative phosphorylation, PI3K-Akt signaling pathway, and MAPK signaling pathway. Subsequent analysis focusing on the apoptosis pathway showed that the expression of Endonuclease G (EndoG) was up-regulated upon RGNNV infection at both 3 and 24 h poi. Therefore, EndoG gene was cloned and its function was further characterized. The results showed that over-expression of EndoG could also induce cellular apoptosis in SSN-1 cells, indicating that RGNNV infection might induce apoptosis of SSN-1 cells via EndoG-associated mitochondrial pathway. These results will shed a new light on the pathogenesis of NNV.
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Affiliation(s)
- Wenjie Chen
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Lizhu Yi
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Shuangshuang Feng
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Xiaodan Liu
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Muhammad Asim
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Yongcan Zhou
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, Haikou 570228, China
| | - Jiangfeng Lan
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Sanjie Jiang
- St Edmund's College, University of Cambridge, Cambridge, CB3 0BN, UK
| | - Jiagang Tu
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
| | - Li Lin
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China; State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, Haikou 570228, China.
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23
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Tsigelny IF, Kouznetsova VL, Lian N, Kesari S. Molecular mechanisms of OLIG2 transcription factor in brain cancer. Oncotarget 2016; 7:53074-53101. [PMID: 27447975 PMCID: PMC5288170 DOI: 10.18632/oncotarget.10628] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 06/03/2016] [Indexed: 12/13/2022] Open
Abstract
Oligodendrocyte lineage transcription factor 2 (OLIG2) plays a pivotal role in glioma development. Here we conducted a comprehensive study of the critical gene regulatory networks involving OLIG2. These include the networks responsible for OLIG2 expression, its translocation to nucleus, cell cycle, epigenetic regulation, and Rho-pathway interactions. We described positive feedback loops including OLIG2: loops of epigenetic regulation and loops involving receptor tyrosine kinases. These loops may be responsible for the prolonged oncogenic activity of OLIG2. The proposed schemes for epigenetic regulation of the gene networks involving OLIG2 are confirmed by patient survival (Kaplan-Meier) curves based on the cancer genome atlas (TCGA) datasets. Finally, we elucidate the Coherent-Gene Modules (CGMs) networks-framework of OLIG2 involvement in cancer. We showed that genes interacting with OLIG2 formed eight CGMs having a set of intermodular connections. We showed also that among the genes involved in these modules the most connected hub is EGFR, then, on lower level, HSP90 and CALM1, followed by three lower levels including epigenetic genes KDM1A and NCOR1. The genes on the six upper levels of the hierarchy are involved in interconnections of all eight CGMs and organize functionally defined gene-signaling subnetworks having specific functions. For example, CGM1 is involved in epigenetic control. CGM2 is significantly related to cell proliferation and differentiation. CGM3 includes a number of interconnected helix-loop-helix transcription factors (bHLH) including OLIG2. Many of these TFs are partially controlled by OLIG2. The CGM4 is involved in PDGF-related: angiogenesis, tumor cell proliferation and differentiation. These analyses provide testable hypotheses and approaches to inhibit OLIG2 pathway and relevant feed-forward and feedback loops to be interrogated. This broad approach can be applied to other TFs.
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Affiliation(s)
- Igor F. Tsigelny
- Department of Neurosciences, University of California San Diego, La Jolla, 92093-0752, CA, USA
- San Diego Supercomputer Center, University of California San Diego, La Jolla, 92093-0505, CA, USA
- Moores Cancer Center, University of California San Diego, La Jolla, 92093, CA, USA
| | - Valentina L. Kouznetsova
- San Diego Supercomputer Center, University of California San Diego, La Jolla, 92093-0505, CA, USA
- Moores Cancer Center, University of California San Diego, La Jolla, 92093, CA, USA
| | - Nathan Lian
- REHS, San Diego Supercomputer Center, University of California San Diego, La Jolla, 92093-0505, CA, USA
| | - Santosh Kesari
- John Wayne Cancer Institute at Providence Saint John's Health Center, Santa Monica, 90404, CA, USA
- Pacific Neuroscience Institute at Providence Saint John's Health Center, Santa Monica, 90404, CA, USA
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24
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Wang X, Ning Y, Zhang F, Yu F, Tan W, Lei Y, Wu C, Zheng J, Wang S, Yu H, Li Z, Lammi MJ, Guo X. Gene expression signature in endemic osteoarthritis by microarray analysis. Int J Mol Sci 2015; 16:11465-81. [PMID: 25997002 PMCID: PMC4463711 DOI: 10.3390/ijms160511465] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 05/03/2015] [Accepted: 05/05/2015] [Indexed: 01/08/2023] Open
Abstract
Kashin-Beck Disease (KBD) is an endemic osteochondropathy with an unknown pathogenesis. Diagnosis of KBD is effective only in advanced cases, which eliminates the possibility of early treatment and leads to an inevitable exacerbation of symptoms. Therefore, we aim to identify an accurate blood-based gene signature for the detection of KBD. Previously published gene expression profile data on cartilage and peripheral blood mononuclear cells (PBMCs) from adults with KBD were compared to select potential target genes. Microarray analysis was conducted to evaluate the expression of the target genes in a cohort of 100 KBD patients and 100 healthy controls. A gene expression signature was identified using a training set, which was subsequently validated using an independent test set with a minimum redundancy maximum relevance (mRMR) algorithm and support vector machine (SVM) algorithm. Fifty unique genes were differentially expressed between KBD patients and healthy controls. A 20-gene signature was identified that distinguished between KBD patients and controls with 90% accuracy, 85% sensitivity, and 95% specificity. This study identified a 20-gene signature that accurately distinguishes between patients with KBD and controls using peripheral blood samples. These results promote the further development of blood-based genetic biomarkers for detection of KBD.
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Affiliation(s)
- Xi Wang
- School of Public Health, Xi'an Jiaotong University Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, No. 76 Yanta West Road, Xi'an 710061, China.
| | - Yujie Ning
- School of Public Health, Xi'an Jiaotong University Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, No. 76 Yanta West Road, Xi'an 710061, China.
| | - Feng Zhang
- School of Public Health, Xi'an Jiaotong University Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, No. 76 Yanta West Road, Xi'an 710061, China.
| | - Fangfang Yu
- School of Public Health, Xi'an Jiaotong University Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, No. 76 Yanta West Road, Xi'an 710061, China.
| | - Wuhong Tan
- School of Public Health, Xi'an Jiaotong University Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, No. 76 Yanta West Road, Xi'an 710061, China.
| | - Yanxia Lei
- School of Public Health, Xi'an Jiaotong University Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, No. 76 Yanta West Road, Xi'an 710061, China.
| | - Cuiyan Wu
- School of Public Health, Xi'an Jiaotong University Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, No. 76 Yanta West Road, Xi'an 710061, China.
| | - Jingjing Zheng
- School of Public Health, Xi'an Jiaotong University Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, No. 76 Yanta West Road, Xi'an 710061, China.
| | - Sen Wang
- School of Public Health, Xi'an Jiaotong University Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, No. 76 Yanta West Road, Xi'an 710061, China.
| | - Hanjie Yu
- National Engineering Research Center for Miniaturized Detection Systems, Northwest University, Xi'an 710069, China.
| | - Zheng Li
- National Engineering Research Center for Miniaturized Detection Systems, Northwest University, Xi'an 710069, China.
| | - Mikko J Lammi
- Department of Integrative Medical Biology, University of Umea, 901 87 Umeå, Sweden.
| | - Xiong Guo
- School of Public Health, Xi'an Jiaotong University Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, No. 76 Yanta West Road, Xi'an 710061, China.
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25
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Gandhi CR, Chaillet JR, Nalesnik MA, Kumar S, Dangi A, Demetris AJ, Ferrell R, Wu T, Divanovic S, Stankeiwicz T, Shaffer B, Stolz DB, Harvey SA, Wang J, Starzl TE. Liver-specific deletion of augmenter of liver regeneration accelerates development of steatohepatitis and hepatocellular carcinoma in mice. Gastroenterology 2015; 148:379-391.e4. [PMID: 25448926 PMCID: PMC4802363 DOI: 10.1053/j.gastro.2014.10.008] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 10/06/2014] [Accepted: 10/07/2014] [Indexed: 12/22/2022]
Abstract
BACKGROUND & AIMS Augmenter of liver regeneration (ALR, encoded by GFER) is a widely distributed pleiotropic protein originally identified as a hepatic growth factor. However, little is known about its roles in hepatic physiology and pathology. We created mice with liver-specific deletion of ALR to study its function. METHODS We developed mice with liver-specific deletion of ALR (ALR-L-KO) using the albumin-Cre/LoxP system. Liver tissues were collected from ALR-L-KO mice and ALR(floxed/floxed) mice (controls) and analyzed by histology, reverse-transcription polymerase chain reaction, immunohistochemistry, electron microscopy, and techniques to measure fibrosis and lipids. Liver tissues from patients with and without advanced liver disease were determined by immunoblot analysis. RESULTS Two weeks after birth, livers of ALR-L-KO mice contained low levels of ALR and adenosine triphosphate (ATP); they had reduced mitochondrial respiratory function and increased oxidative stress, compared with livers from control mice, and had excessive steatosis, and hepatocyte apoptosis. Levels of carbamyl-palmitoyl transferase 1a and ATP synthase subunit ATP5G1 were reduced in livers of ALR-L-KO mice, indicating defects in mitochondrial fatty acid transport and ATP synthesis. Electron microscopy showed mitochondrial swelling with abnormalities in shapes and numbers of cristae. From weeks 2-4 after birth, levels of steatosis and apoptosis decreased in ALR-L-KO mice, and numbers of ALR-expressing cells increased, along with ATP levels. However, at weeks 4-8 after birth, livers became inflamed, with hepatocellular necrosis, ductular proliferation, and fibrosis; hepatocellular carcinoma developed by 1 year after birth in nearly 60% of the mice. Hepatic levels of ALR were also low in ob/ob mice and alcohol-fed mice with liver steatosis, compared with controls. Levels of ALR were lower in liver tissues from patients with advanced alcoholic liver disease and nonalcoholic steatohepatitis than in control liver tissues. CONCLUSIONS We developed mice with liver-specific deletion of ALR, and showed that it is required for mitochondrial function and lipid homeostasis in the liver. ALR-L-KO mice provide a useful model for investigating the pathogenesis of steatohepatitis and its complications.
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Affiliation(s)
- Chandrashekhar R. Gandhi
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA,Department of Surgery, University of Cincinnati, Cincinnati, Ohio, USA,Cincinnati VA Medical Center, Cincinnati, Ohio, USA,Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA,Corresponding Author: Department of Surgery ML0558 University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH, 45267-0558. Phone: 513.558.7272 Fax: 513-558-8677
| | - J. Richard Chaillet
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Michael A. Nalesnik
- Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA,Department of Pathology, University of Pittsburgh, Pennsylvania, USA
| | - Sudhir Kumar
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Anil Dangi
- Department of Surgery, University of Cincinnati, Cincinnati, Ohio, USA,Cincinnati VA Medical Center, Cincinnati, Ohio, USA
| | - A. Jake Demetris
- Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA,Department of Pathology, University of Pittsburgh, Pennsylvania, USA
| | - Robert Ferrell
- School of Public Health, University of Pittsburgh, Pennsylvania, USA
| | - Tong Wu
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana, USA
| | - Senad Divanovic
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Traci Stankeiwicz
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Benjamin Shaffer
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Donna B. Stolz
- Department of Cell Biology, University of Pittsburgh, Pennsylvania, USA
| | | | - Jiang Wang
- Department of pathology & Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio, USA
| | - Thomas E. Starzl
- Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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26
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Lee SK, Zhao MH, Zheng Z, Kwon JW, Liang S, Kim SH, Kim NH, Cui XS. Polymerase subunit gamma 2 affects porcine oocyte maturation and subsequent embryonic development. Theriogenology 2014; 83:121-30. [PMID: 25308052 DOI: 10.1016/j.theriogenology.2014.08.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 07/16/2014] [Accepted: 08/31/2014] [Indexed: 01/30/2023]
Abstract
Deoxyribonucleic acid polymerase subunit gamma (POLG) is an enzyme encoded by the mitochondrial Polg gene. Polymerase (DNA directed), gamma 2, accessory subunit, also known as POLG2, is involved in mitochondrial replication. In the present study, we examined the role of Polg2 in the maturation of porcine oocytes. After Polg2 knockdown, the mitochondrial DNA copy number was significantly (P < 0.05) lower than that in the control group. However, there was no decrease in mitochondrial membrane potential. The decrease in mitochondrial DNA copy number led to reductions in adenosine-5'-triphosphate content (P < 0.05) and the maturation rate (P < 0.05) of oocytes. Furthermore, in the Polg2-knockdown group, maturation-promoting factor activity was decreased (P < 0.05) and the percentage of oocytes displaying abnormal actin filaments and microtubules was significantly increased (P < 0.05). This likely led to the reduced development rate and number of cells per blastocyst in this group (P < 0.05). In conclusion, Polg2 seems to be critical for mitochondrial replication and regulation of adenosine-5'-triphosphate content and affects porcine oocyte maturation and subsequent embryonic development.
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Affiliation(s)
- Seul-Ki Lee
- Department of Animal Sciences, Chungbuk National University, Cheongju, South Korea; Brain Korea 21 Center for Bio-Resource Development, Cheongju, South Korea
| | - Ming-Hui Zhao
- Department of Animal Sciences, Chungbuk National University, Cheongju, South Korea; Brain Korea 21 Center for Bio-Resource Development, Cheongju, South Korea
| | - Zhong Zheng
- Department of Animal Sciences, Chungbuk National University, Cheongju, South Korea; Brain Korea 21 Center for Bio-Resource Development, Cheongju, South Korea
| | - Jung-Woo Kwon
- Department of Animal Sciences, Chungbuk National University, Cheongju, South Korea; Brain Korea 21 Center for Bio-Resource Development, Cheongju, South Korea
| | - Shuang Liang
- Department of Animal Sciences, Chungbuk National University, Cheongju, South Korea; Brain Korea 21 Center for Bio-Resource Development, Cheongju, South Korea
| | - Seon-Hyang Kim
- Department of Animal Sciences, Chungbuk National University, Cheongju, South Korea; Brain Korea 21 Center for Bio-Resource Development, Cheongju, South Korea
| | - Nam-Hyung Kim
- Department of Animal Sciences, Chungbuk National University, Cheongju, South Korea; Brain Korea 21 Center for Bio-Resource Development, Cheongju, South Korea
| | - Xiang-Shun Cui
- Department of Animal Sciences, Chungbuk National University, Cheongju, South Korea; Brain Korea 21 Center for Bio-Resource Development, Cheongju, South Korea.
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27
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Lan L, Nakajima S, Wei L, Sun L, Hsieh CL, Sobol RW, Bruchez M, Van Houten B, Yasui A, Levine AS. Novel method for site-specific induction of oxidative DNA damage reveals differences in recruitment of repair proteins to heterochromatin and euchromatin. Nucleic Acids Res 2013; 42:2330-45. [PMID: 24293652 PMCID: PMC3936713 DOI: 10.1093/nar/gkt1233] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Reactive oxygen species (ROS)-induced DNA damage is repaired by the base excision repair pathway. However, the effect of chromatin structure on BER protein recruitment to DNA damage sites in living cells is poorly understood. To address this problem, we developed a method to specifically produce ROS-induced DNA damage by fusing KillerRed (KR), a light-stimulated ROS-inducer, to a tet-repressor (tetR-KR) or a transcription activator (TA-KR). TetR-KR or TA-KR, bound to a TRE cassette (∼90 kb) integrated at a defined genomic locus in U2OS cells, was used to induce ROS damage in hetero- or euchromatin, respectively. We found that DNA glycosylases were efficiently recruited to DNA damage in heterochromatin, as well as in euchromatin. PARP1 was recruited to DNA damage within condensed chromatin more efficiently than in active chromatin. In contrast, recruitment of FEN1 was highly enriched at sites of DNA damage within active chromatin in a PCNA- and transcription activation-dependent manner. These results indicate that oxidative DNA damage is differentially processed within hetero or euchromatin.
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Affiliation(s)
- Li Lan
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, 5117 Centre Avenue, Pittsburgh, PA 15213, USA, School of Medicine, Tsinghua University, No.1 Tsinghua Yuan, Haidian District, Beijing 100084, People's Republic of China, Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA, Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA 15213, USA, Department of Chemistry and Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA and Division of Dynamic Proteome, Institute of Development, Aging, and Cancer, Tohoku University, Seiryomachi 4-1, Sendai 980-8575, Japan
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28
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Schmitt K, Reichrath J, Roesch A, Meese E, Mayer J. Transcriptional profiling of human endogenous retrovirus group HERV-K(HML-2) loci in melanoma. Genome Biol Evol 2013; 5:307-28. [PMID: 23338945 PMCID: PMC3590776 DOI: 10.1093/gbe/evt010] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Recent studies suggested a role for the human endogenous retrovirus (HERV) group HERV-K(HML-2) in melanoma because of upregulated transcription and expression of HERV-K(HML-2)-encoded proteins. Very little is known about which HML-2 loci are transcribed in melanoma. We assigned >1,400 HML-2 cDNA sequences generated from various melanoma and related samples to genomic HML-2 loci, identifying a total of 23 loci as transcribed. Transcription profiles of loci differed significantly between samples. One locus was found transcribed only in melanoma-derived samples but not in melanocytes and might represent a marker for melanoma. Several of the transcribed loci harbor ORFs for retroviral Gag and/or Env proteins. Env-encoding loci were transcribed only in melanoma. Specific investigation of rec and np9 transcripts indicated transcription of protein encoding loci in melanoma and melanocytes hinting at the relevance of Rec and Np9 in melanoma. UVB irradiation changed transcription profiles of loci and overall transcript levels decreased in melanoma and melanocytes. We further identified transcribed HML-2 loci formed by reverse transcription of spliced HML-2 transcripts by L1 machinery or in a retroviral fashion, with loci potentially encoding HML-2-like proteins. We reveal complex, sample-specific transcription of HML-2 loci in melanoma and related samples. Identified HML-2 loci and proteins encoded by those loci are particularly relevant for further studying the role of HML-2 in melanoma. Transcription of HERVs appears as a complex mechanism requiring specific studies to elucidate which HERV loci are transcribed and how transcribed HERVs may be involved in disease.
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Affiliation(s)
- Katja Schmitt
- Institute of Human Genetics, Medical Faculty, University of Saarland, Homburg/Saar, Germany
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29
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Mitochondrial nucleases ENDOG and EXOG participate in mitochondrial DNA depletion initiated by herpes simplex virus 1 UL12.5. J Virol 2013; 87:11787-97. [PMID: 23986585 DOI: 10.1128/jvi.02306-13] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Herpes simplex virus 1 (HSV-1) rapidly eliminates mitochondrial DNA (mtDNA) from infected cells, an effect that is mediated by UL12.5, a mitochondrial isoform of the viral alkaline nuclease UL12. Our initial hypothesis was that UL12.5 directly degrades mtDNA via its nuclease activity. However, we show here that the nuclease activities of UL12.5 are not required for mtDNA loss. This observation led us to examine whether cellular nucleases mediate the mtDNA loss provoked by UL12.5. We provide evidence that the mitochondrial nucleases endonuclease G (ENDOG) and endonuclease G-like 1 (EXOG) play key redundant roles in UL12.5-mediated mtDNA depletion. Overall, our data indicate that UL12.5 deploys cellular proteins, including ENDOG and EXOG, to destroy mtDNA and contribute to a growing body of literature highlighting roles for ENDOG and EXOG in mtDNA maintenance.
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30
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Aleksandrushkina NI, Vanyushin BF. Endonucleases and apoptosis in animals. BIOCHEMISTRY (MOSCOW) 2013; 77:1436-51. [PMID: 23379520 DOI: 10.1134/s0006297912130032] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Endonucleases are the main instruments of obligatory DNA degradation in apoptosis. Many endonucleases have marked processive action; initially they split DNA in chromatin into very large domains, and then they perform in it internucleosomal fragmentation of DNA followed by its hydrolysis to small fragments (oligonucleotides). During apoptosis, DNA of chromatin is attacked by many nucleases that are different in activity, specificity, and order of action. The activity of every endonuclease is regulated in the cell through its own regulatory mechanism (metal ions and other effectors, possibly also S-adenosylmethionine). Apoptosis is impossible without endonucleases as far as it leads to accumulation of unnecessary (defective) DNA, disorders in cell differentiation, embryogenesis, the organism's development, and is accompanied by various severe diseases. The interpretation of the structure and functions of endonucleases and of the nature and action of their modulating effectors is important not only for elucidation of mechanisms of apoptosis, but also for regulation and control of programmed cell death, cell differentiation, and development of organisms.
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Affiliation(s)
- N I Aleksandrushkina
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
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Chitooligosaccharide induces mitochondrial biogenesis and increases exercise endurance through the activation of Sirt1 and AMPK in rats. PLoS One 2012; 7:e40073. [PMID: 22808092 PMCID: PMC3394803 DOI: 10.1371/journal.pone.0040073] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 05/31/2012] [Indexed: 01/28/2023] Open
Abstract
By catabolizing glucose and lipids, mitochondria produce ATPs to meet energy demands. When the number and activity of mitochondria are not sufficient, the human body becomes easily fatigued due to the lack of ATP, thus the control of the quantity and function of mitochondria is important to optimize energy balance. By increasing mitochondrial capacity? it may be possible to enhance energy metabolism and improve exercise endurance. Here, through the screening of various functional food ingredients, we found that chitooligosaccharide (COS) is an effective inducer of mitochondrial biogenesis. In rodents, COS increased the mitochondrial content in skeletal muscle and enhanced exercise endurance. In cultured myocytes, the expression of major regulators of mitochondrial biogenesis and key components of mitochondrial electron transfer chain was increased upon COS treatment. COS-mediated induction of mitochondrial biogenesis was achieved in part by the activation of silent information regulator two ortholog 1 (Sirt1) and AMP-activated protein kinase (AMPK). Taken together, our data suggest that COS could act as an exercise mimetic by inducing mitochondrial biogenesis and enhancing exercise endurance through the activation of Sirt1 and AMPK.
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Zinc-finger protein 331, a novel putative tumor suppressor, suppresses growth and invasiveness of gastric cancer. Oncogene 2012; 32:307-17. [PMID: 22370639 DOI: 10.1038/onc.2012.54] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Zinc-finger protein 331 (ZNF331), a Kruppel-associated box zinc-finger protein gene, was identified as a putative tumor suppressor in our previous study. However, the role of ZNF331 in tumorigenesis remains elusive. We aimed to clarify its epigenetic regulation and biological functions in gastric cancer. ZNF331 was silenced or downregulated in 71% (12/17) gastric cancer cell lines. A significant downregulation was also detected in paired gastric tumors compared with adjacent non-cancer tissues. In contrast, ZNF331 was readily expressed in various normal adult tissues. The downregulation of ZNF331 was closely linked to the promoter hypermethylation as evidenced by methylation-specific PCR, bisulfite genomic sequencing and reexpression by demethylation agent treatment. DNA sequencing showed no genetic mutation/deletion of ZNF331 in gastric cancer cell lines. Ectopic expression of ZNF331 in the silenced cancer cell lines MKN28 and HCT116 significantly reduced colony formation and cell viability, induced cell cycle arrests and repressed cell migration and invasive ability. Concordantly, knockdown of ZNF331 increased cell viability and colony formation ability of gastric cancer cell line MKN45. Two-dimensional gel electrophoresis and mass spectrometry-based comparative proteomic approach were applied to analyze the molecular basis of the biological functions of ZNF331. In all, 10 downstream targets of ZNF331 were identified to be associated with regulation of cell growth and metastasis. The tumor-suppressive effect of ZNF331 is mediated at least by downregulation of genes involved in cell growth promotion (DSTN, EIF5A, GARS, DDX5, STAM, UQCRFS1 and SET) and migration/invasion (DSTN and ACTR3), and upregulation of genome-stability gene (SSBP1) and cellular senescence gene (PNPT1). A novel target of ZNF331 (DSTN) was functionally validated. Overexpression of DSTN in BGC-823 cells increased colony formation and migration ability. In conclusion, our results suggest that ZNF331 possesses important functions for the suppression of gastric carcinogenesis as a novel functional tumor-suppressor gene.
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McDermott-Roe C, Ye J, Ahmed R, Sun XM, Serafín A, Ware J, Bottolo L, Muckett P, Cañas X, Zhang J, Rowe GC, Buchan R, Lu H, Braithwaite A, Mancini M, Hauton D, Martí R, García-Arumí E, Hubner N, Jacob H, Serikawa T, Zidek V, Papousek F, Kolar F, Cardona M, Ruiz-Meana M, García-Dorado D, Comella JX, Felkin LE, Barton PJR, Arany Z, Pravenec M, Petretto E, Sanchis D, Cook SA. Endonuclease G is a novel determinant of cardiac hypertrophy and mitochondrial function. Nature 2011; 478:114-8. [PMID: 21979051 PMCID: PMC3189541 DOI: 10.1038/nature10490] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2011] [Accepted: 08/17/2011] [Indexed: 12/31/2022]
Abstract
Left ventricular mass (LVM) is a highly heritable trait and an independent risk factor for all-cause mortality. So far, genome-wide association studies have not identified the genetic factors that underlie LVM variation, and the regulatory mechanisms for blood-pressure-independent cardiac hypertrophy remain poorly understood. Unbiased systems genetics approaches in the rat now provide a powerful complementary tool to genome-wide association studies, and we applied integrative genomics to dissect a highly replicated, blood-pressure-independent LVM locus on rat chromosome 3p. Here we identified endonuclease G (Endog), which previously was implicated in apoptosis but not hypertrophy, as the gene at the locus, and we found a loss-of-function mutation in Endog that is associated with increased LVM and impaired cardiac function. Inhibition of Endog in cultured cardiomyocytes resulted in an increase in cell size and hypertrophic biomarkers in the absence of pro-hypertrophic stimulation. Genome-wide network analysis unexpectedly implicated ENDOG in fundamental mitochondrial processes that are unrelated to apoptosis. We showed direct regulation of ENDOG by ERR-α and PGC1α (which are master regulators of mitochondrial and cardiac function), interaction of ENDOG with the mitochondrial genome and ENDOG-mediated regulation of mitochondrial mass. At baseline, the Endog-deleted mouse heart had depleted mitochondria, mitochondrial dysfunction and elevated levels of reactive oxygen species, which were associated with enlarged and steatotic cardiomyocytes. Our study has further established the link between mitochondrial dysfunction, reactive oxygen species and heart disease and has uncovered a role for Endog in maladaptive cardiac hypertrophy.
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Affiliation(s)
- Chris McDermott-Roe
- Medical Research Council Clinical Sciences Centre, Faculty of Medicine, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 ONN, UK
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Hong KW, Shin YB, Kim KH, Oh BS. Differentially Expressed Genes by Inhibition of C-terminal Src Kinase by siRNA in Human Vascular Smooth Muscle Cells and Their Association with Blood Pressure. Genomics Inform 2011. [DOI: 10.5808/gi.2011.9.3.102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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Byeon JS, Jeong JY, Kim MJ, Lee SM, Nam WH, Myung SJ, Kim JG, Yang SK, Kim JH, Suh DJ. Adiponectin and adiponectin receptor in relation to colorectal cancer progression. Int J Cancer 2011; 127:2758-67. [PMID: 21351255 DOI: 10.1002/ijc.25301] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Although obesity is a risk factor for colorectal cancer, the underlying mechanism is not clear. Adiponectin is an adipokine that binds to 2 types of receptors, AdipoR1 and AdipoR2. The plasma concentrations of adiponectin are reduced in obese individuals and adiponectin has been reported to have anticarcinogenic properties. Furthermore, AdipoR1 and AdipoR2 have been reported to be expressed in several malignancies. However, little is known about the expression of AdipoR1 and AdipoR2 in colorectal cancer and its clinicopathological implications. In addition, the relationship between adiponectin and colorectal cancer has not yet been determined. Here, we sought to investigate adiponectin and adiponectin receptors in relation to colorectal cancer. AdipoR1 and AdipoR2 immunostaining was detected in 72 and 68% of human colorectal cancer tissue, respectively. AdipoR1 and AdipoR2 expression levels were inversely related to T stage. The lowest AdipoR1 and AdipoR2 expression were detected in poorly differentiated adenocarcinoma. RT-PCR also showed the expression of AdipoR1 and AdipoR2 in HCT116 and SW620. MTT assay and TUNEL assay demonstrated the tendency of growth inhibition and apoptosis induction in both cell lines after full-length adiponectin treatment although statistically insignificant. Microarray analysis revealed several gene responses to full-length adiponectin, including upregulation of ENDOGL1 and MT1G. In conclusion, AdipoR1 and AdipoR2 may be intimately related to the progression of colorectal cancer. Further studies may be warranted to assess adiponectin and its receptors as a novel target for inhibition of colorectal cancer growth.
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Affiliation(s)
- Jeong-Sik Byeon
- Department of Gastroenterology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea
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Santandreu FM, Oliver J, Roca P. Improvement of mitochondrial energy and oxidative balance during intestinal differentiation. Mitochondrion 2010; 11:89-96. [PMID: 20696280 DOI: 10.1016/j.mito.2010.07.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 07/05/2010] [Accepted: 07/23/2010] [Indexed: 02/01/2023]
Abstract
Mitochondria vary in their number and function, but how these variations are associated with intestinal cell differentiation remains elusive. The object of this study was to investigate the underlying mechanisms of inosine-mediated intestinal cell maturation, analysing the effects of this nutrient on metabolic functionality, mitochondrial biogenesis and mitochondrial function in human colonic cells. The role of oxidative stress in the control of intestinal cell growth was also explored. We report the novel finding that inosine-mediated differentiation improves aerobic metabolism through an increase in mitochondrial bioenergetics and biogenesis in colonic cells, which probably confers them greater resistance to cytotoxic oxidative stress.
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Affiliation(s)
- Francisca M Santandreu
- Grupo Multidisciplinar de Oncología Traslacional, Institut Universitari d'Investigació en Ciències de la Salut, Universitat de les Illes Balears, Palma de Mallorca, Illes Balears, Spain
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Eichhorn-Mulligan K, Cestari DM. The genetics of leber hereditary optic neuropathy--prototype of an inherited optic neuropathy with mitochondrial dysfunction. Semin Ophthalmol 2008; 23:27-37. [PMID: 18214789 DOI: 10.1080/08820530701745207] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Leber Hereditary Optic Neuropathy is a maternally inherited condition that is characterized by acute or subacute bilateral loss of vision, usually in otherwise healthy young individuals. Several point mutations in the mitochondrial genome have been identified in patients with the condition. Scientific advances into a better understanding of the molecular pathogenesis have been hampered by the lack of an animal model for the disease. This article summarizes what is known about the clinical features, epidemiology and genetics of Leber Hereditary Optic Neuropathy and reviews recent experiments scientists have used in addressing the many unanswered questions that remain about the disease.
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Affiliation(s)
- Knut Eichhorn-Mulligan
- Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA.
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Belin AC, Björk BF, Westerlund M, Galter D, Sydow O, Lind C, Pernold K, Rosvall L, Håkansson A, Winblad B, Nissbrandt H, Graff C, Olson L. Association study of two genetic variants in mitochondrial transcription factor A (TFAM) in Alzheimer's and Parkinson's disease. Neurosci Lett 2007; 420:257-62. [PMID: 17537576 DOI: 10.1016/j.neulet.2007.05.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2007] [Revised: 05/02/2007] [Accepted: 05/03/2007] [Indexed: 01/15/2023]
Abstract
Mitochondrial (mt) dysfunction has been implicated in Alzheimer's (AD) and Parkinson's disease (PD). Mitochondrial transcription factor A (TFAM) is needed for mtDNA maintenance, regulating mtDNA copy number and is absolutely required for transcriptional initiation at mtDNA promoters. Two genetic variants in TFAM have been reported to be associated with AD in a Caucasian case-control material collected from Germany, Switzerland and Italy. One of these variants was reported to show a tendency for association with AD in a pooled Scottish and Swedish case-control material and the other variant was reported to be associated with AD in a recent meta-analysis. We investigated these two genetic variants, rs1937 and rs2306604, in an AD and a PD case-control material, both from Sweden and found significant genotypic as well as allelic association to marker rs2306604 in the AD case-control material (P=0.05 and P=0.03, respectively), where the A-allele appears to increase risk for developing AD. No association was observed for marker rs1937. We did not find any association in the PD case-control material for either of the two markers. The distribution of the two-locus haplotype frequencies (based on rs1937 and rs2306604) did not differ significantly between affected individuals and controls in the two sample sets. However, the global P-value for haplotypic association testing indicated borderline association in the AD sample set. Our data suggests that the rs2306604 A-allele could be a moderate risk factor for AD, which is supported by the recent meta-analysis.
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Affiliation(s)
- Andrea Carmine Belin
- Department of Neuroscience, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden.
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Moritani M, Nomura K, Tanahashi T, Osabe D, Fujita Y, Shinohara S, Yamaguchi Y, Keshavarz P, Kudo E, Nakamura N, Yoshikawa T, Ichiishi E, Takata Y, Yasui N, Shiota H, Kunika K, Inoue H, Itakura M. Genetic association of single nucleotide polymorphisms in endonuclease G-like 1 gene with type 2 diabetes in a Japanese population. Diabetologia 2007; 50:1218-27. [PMID: 17415550 DOI: 10.1007/s00125-007-0631-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2006] [Accepted: 01/21/2007] [Indexed: 11/29/2022]
Abstract
AIMS/HYPOTHESIS In order to identify type 2 diabetes disease susceptibility gene(s) in a Japanese population, we applied a region-wide case-control association test to the 20.4 Mb region between D3S1293 and D3S2319 on chromosome 3p24.3-22.1, supported by linkage to type 2 diabetes and its related traits in Japanese and multiple populations. MATERIALS AND METHODS We performed a two-stage association test using 1,762 Japanese persons with 485 gene-centric, evenly spaced, common single nucleotide polymorphism (SNP) markers with minor allele frequency >0.1. For mouse studies, total RNA was extracted from various organs of BKS.Cg-+Lepr(db)/+Lepr(db) and control mice, and from MIN6, NIH3T3 and C2C12 cell lines. RESULTS We detected a landmark SNP375 (A/G) (rs2051211, p = 0.000046, odds ratio = 1.33, 95% CI 1.16-1.53) in intron 5 of the endonuclease G-like 1 (ENDOGL1) gene. Systematic dense SNPs approach identified a susceptibility linkage disequilibrium (LD) block of 116.5 kb by |D'|, an LD units map and a critical region of 2.1 kb by r (2) in ENDOGL1. A haplotype-based association test showed that an at-risk haplotype is associated with disease status (p = 0.00001). The expression of ENDOGL1 was rather ubiquitous with relatively abundant expression in the brain and also in a pancreatic islet beta cell line. Mouse Endogl1 expression increased in pancreatic islets of hyperglycaemic BKS.Cg-+Lepr(db)/+Lepr(db) mice compared with that in control mice. CONCLUSIONS/INTERPRETATION Based on the population genetics, fine mapping of LD block and haplotype analysis, we conclude that ENDOGL1 is a candidate disease-susceptibility gene for type 2 diabetes in a Japanese population. Further analysis in a larger sample size is required to substantiate this conclusion.
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Affiliation(s)
- M Moritani
- Division of Genetic Information, Institute for Genome Research, The University of Tokushima, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan
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Berdanier CD. Mitochondrial gene expression: influence of nutrients and hormones. Exp Biol Med (Maywood) 2006; 231:1593-601. [PMID: 17060679 DOI: 10.1177/153537020623101003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Mitochondrial gene transcription research has exploded over the last decade. Nuclear-encoded proteins, nutrients, and hormones all work to regulate the transcription of this genome. To date, very few of the transcription factors have been shown to have negative effects on mitochondrial gene expression, although there are likely conditions where such downregulation may occur.
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Ishihara Y, Shimamoto N. Involvement of endonuclease G in nucleosomal DNA fragmentation under sustained endogenous oxidative stress. J Biol Chem 2006; 281:6726-33. [PMID: 16407272 DOI: 10.1074/jbc.m510382200] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have previously shown that inhibition of catalase and glutathione peroxidase activities by 3-amino-1,2,4-triazole (ATZ) and mercaptosuccinic acid (MS), respectively, in rat primary hepatocytes caused sustained endogenous oxidative stress and apoptotic cell death without caspase-3 activation. In this study, we investigated the mechanism of this apoptotic cell death in terms of nucleosomal DNA fragmentation. Treatment with ATZ+MS time-dependently increased the number of deoxynucleotidyl transferase-mediated nick end-labeling (TUNEL)-positive nuclei from 12 h, resulting in clear DNA laddering at 24 h. The deoxyribonuclease (DNase) inhibitor, aurintricarboxylic acid (ATA), completely inhibited nucleosomal DNA fragmentation but the pan-caspase inhibitor, z-VAD-fmk was without effects; furthermore, the cleavage of inhibitor of caspase-activated DNase was not detected, indicating the involvement of DNase(s) other than caspase-activated DNase. Considering that endonuclease G (EndoG) reportedly acts in a caspase-independent manner, we cloned rat EndoG cDNA for the first time. Recombinant EndoG alone digested plasmid DNA and induced nucleosomal DNA fragmentation in isolated hepatocyte nuclei. Recombinant EndoG activity was inhibited by ATA but not by hydrogen peroxide, even at 10 mm. ATZ+MS stimulation elicited decreases in mitochondrial membrane potential and EndoG translocation from mitochondria to nuclei. By applying RNA interference, the mRNA levels of EndoG were almost completely suppressed and the amount of EndoG protein was decreased to approximately half the level of untreated cells. Under these conditions, decreases in TUNEL-positive nuclei were significantly suppressed. These results indicate that EndoG is responsible, at least in part, for nucleosomal DNA fragmentation under endogenous oxidative stress conditions induced by ATZ+MS.
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Affiliation(s)
- Yasuhiro Ishihara
- Department of Biology, Graduate School of Science, Osaka University, Osaka 532-8686, Japan
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D'Errico I, Dinardo MM, Capozzi O, De Virgilio C, Gadaleta G. History of the Tfam gene in primates. Gene 2005; 362:125-32. [PMID: 16202542 DOI: 10.1016/j.gene.2005.07.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2005] [Revised: 07/05/2005] [Accepted: 07/07/2005] [Indexed: 10/25/2022]
Abstract
Tfam is a single copy nuclear gene mapping on chromosome 10 in human and mouse, 20 in rat and 12 in Presbytis cristata. It encodes for an HMG (high-mobility-group) protein showing a high affinity with the two transcriptional promoters and other mitochondrial DNA regions. It is an activator of mitochondrial transcription acting in the presence of mitochondrial RNA polymerase and of transcription factor B. Other interesting features of Tfam gene in human and rat are reported such as the existence of a smaller isoform, originated by an alternative splicing mechanism of the exon 5 (delta5 isoform) and the presence of different processed pseudogenes in addition to the active copy of the gene. In order to widen knowledge about Tfam gene and the appearance of some of its properties in the evolutionary history of primates, we have studied some aspects of this gene in different species. In particular we have determined its chromosomal localization, suggesting that its locus is highly conserved; we have searched for the presence of the delta5 isoform, demonstrating that it is present only in hominids; we have provided evidence of Tfam processed pseudogenes in the majority of the analysed genomes. Sequence data from this article have been deposited in the EMBL nucleotide database.
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Affiliation(s)
- Ilenia D'Errico
- Dipartimento di Biochimica e Biologia Molecolare, Università degli studi di Bari, via Orabona 4/A, 70125, Bari, Italy
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Low RL. Mitochondrial Endonuclease G function in apoptosis and mtDNA metabolism: a historical perspective. Mitochondrion 2005; 2:225-36. [PMID: 16120323 DOI: 10.1016/s1567-7249(02)00104-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2002] [Revised: 10/23/2002] [Accepted: 10/25/2002] [Indexed: 11/24/2022]
Abstract
All mitochondria contain a single, major Mg2+-dependent nuclease capable of extensively degrading DNA and RNA in vitro. This nuclease activity and its gene now go by the name Endonuclease G. For many years, however, a number of different names for this mitochondrial nuclease have been used. This can lead to great deal of confusion for anyone searching the literature. The name Endonuclease G had originally been assigned to an endonuclease activity identified in nuclear extracts of chicken erythrocytes that was found to specifically nick within guanine (G) tracts in DNA in vitro. Subsequent studies however, established that this Endonuclease G activity was identical to the well known, major endonuclease activity isolated from mitochondria of several species. In addition, studies of the mammalian mitochondrial endonuclease showed that the endonuclease is not restricted to only attacking guanine tracts, although it does so avidly. The enzyme is also capable of avidly nicking within cytosine tracts, and at a large variety of sites, that fragments duplex DNA extensively. Despite this, the name Endonuclease G persists. One purpose of this review is to summarize the history of Endonuclease G that spans some 40 years, and review what we have learned about the enzyme's biochemical and biologic properties. Endonuclease G likely serves a role in repair and/or degradation of damaged mtDNA in vivo. Recently, genetic and biochemical evidence has emerged that Endonuclease G is released from the inter membrane space during early stages of programmed cell death, and translocates to the nucleus where it presumably facilitates degradation of chromatin. This exciting new potential role for the enzyme in apoptotic cell death will be discussed.
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Affiliation(s)
- Robert L Low
- Department of Pathology, University of Colorado Health Sciences Center, 4200 East Ninth Avenue, B216, Denver, CO 80262, USA.
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Taanman JW, Llewelyn Williams S. The Human Mitochondrial Genome. OXIDATIVE STRESS AND DISEASE 2005. [DOI: 10.1201/9781420028843.ch3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Chipuk JE, Green DR. Do inducers of apoptosis trigger caspase-independent cell death? Nat Rev Mol Cell Biol 2005; 6:268-75. [PMID: 15714200 DOI: 10.1038/nrm1573] [Citation(s) in RCA: 248] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Apoptotic cell death is mediated by molecular pathways that culminate in the activation of a family of cysteine proteases, known as the caspases, which orchestrate the dismantling and clearance of the dying cell. However, mounting evidence indicates that a cell that has been treated with an apoptotic inducer can also initiate a suicide programme that does not rely on caspase activation. Here, we present recent findings and discuss the physiological relevance of caspase-independent cell death.
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Affiliation(s)
- Jerry E Chipuk
- Division of Cellular Immunology, La Jolla Institute for Allergy and Immunology, 10355 Science Center Drive, San Diego, California 92121, USA.
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Masmoudi S, Charfedine I, Rebeh IB, Rebai A, Tlili A, Ghorbel AM, Belguith H, Petit C, Drira M, Ayadi H. Refined mapping of the autosomal recessive non-syndromic deafness locus DFNB13 using eight novel microsatellite markers. Clin Genet 2004; 66:358-64. [PMID: 15355440 DOI: 10.1111/j.1399-0004.2004.00311.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The locus for a type of an autosomal recessive non-syndromic deafness (ARND), DFNB13, was previously mapped to a 17-cm interval of chromosome 7q34-36. We identified two consanguineous Tunisian families with severe to profound ARND. Linkage analyses with microsatellites surrounding the previously identified loci detected linkage with markers corresponding to the DFNB13 locus in both families. Haplotype analyses assigned this locus to a 3.2-Mb region between markers D7S2468 and D7S2473. In order to refine this interval, we identified nine dinucleotide repeats in the 7q34 region. To investigate the polymorphism of these repeats, a population study of 74 unrelated individuals from different regions of Tunisia was carried out. Our results demonstrated that eight of the nine repeats are polymorphic. The average number of alleles at these informative loci was 9.12 with a polymorphism information content of 0.71. Little evidence for linkage disequilibrium between some marker pairs was found. Haplotype analysis using these microsatellites refined the DFNB13 interval to an area of 2.2 Mb between the D7S5377 and D7S2473. In order to identify the DFNB13 gene, we sequenced and eliminated three candidate genes. Other known and predicted genes are being screened for deafness-causing mutations.
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Affiliation(s)
- S Masmoudi
- Laboratoire de Génétique Moléculaire Humaine, Faculté de Médecine de Sfax, Sfax, Tunisie
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Gil ME, Coetzer TL. Real-time quantitative RT-PCR for human telomere elongation reverse transcriptase in chronic myeloid leukemia. Leuk Res 2004; 28:969-72. [PMID: 15234574 DOI: 10.1016/j.leukres.2004.01.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2003] [Accepted: 01/07/2004] [Indexed: 10/26/2022]
Abstract
Telomeres cap chromosome ends and are pivotal for DNA stability. Deregulation of the telomere stabilising enzyme telomerase in malignancy has implications in diagnosis, prognosis and therapeutics of cancer. Quantification of the expression of the telomerase catalytic subunit, hTERT, using the LightCycler TeloTAGGG hTERT Quantification kit is not optimal for analysis of chronic myeloid leukemia (CML) samples. The internal control, porphobilinogen deaminase (PBGD) is amplified in a separate tube to hTERT and has an unstable genomic localisation of 11q23. Our laboratory thus developed a real-time reverse transcriptase polymerase chain reaction which co-amplifies hTERT and either mitochondrial single-stranded DNA binding protein 1 (ssBP1) or ubiquitin C (UBC).
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Affiliation(s)
- Marcel E Gil
- Department of Molecular Medicine and Haematology, School of Pathology, University of the Witwatersrand, 7 York Road, Parktown, 2193 Johannesburg, South Africa.
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48
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Schäfer P, Scholz SR, Gimadutdinow O, Cymerman IA, Bujnicki JM, Ruiz-Carrillo A, Pingoud A, Meiss G. Structural and functional characterization of mitochondrial EndoG, a sugar non-specific nuclease which plays an important role during apoptosis. J Mol Biol 2004; 338:217-28. [PMID: 15066427 DOI: 10.1016/j.jmb.2004.02.069] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2003] [Revised: 02/11/2004] [Accepted: 02/24/2004] [Indexed: 11/26/2022]
Abstract
Combining sequence analysis, structure prediction, and site-directed mutagenesis, we have investigated the mechanism of catalysis and substrate binding by the apoptotic mitochondrial nuclease EndoG, which belongs to the large family of DNA/RNA non-specific betabetaalpha-Me-finger nucleases. Catalysis of phosphodiester bond cleavage involves several highly conserved amino acid residues, namely His143, Asn174, and Glu182 required for water activation and metal ion binding, as well as Arg141 required for proper substrate binding and positioning, respectively. These results indicate that EndoG basically follows a similar mechanism as the Serratia nuclease, the best studied representative of the family of DNA/RNA non-specific nucleases, but that differences are observed for transition state stabilisation. In addition, we have identified two putative DNA/RNA binding residues of bovine EndoG, Arg135 and Arg186, strictly conserved only among mammalian members of the nuclease family, suggesting a similar mode of binding to single and double-stranded nucleic acid substrates by these enzymes. Finally, we demonstrate by ectopic expression of active and inactive variants of bovine EndoG in HeLa and CV1-cells that extramitochondrial active EndoG by itself induces cell death, whereas expression of an enzymatically inactive variant does not.
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Affiliation(s)
- Patrick Schäfer
- Institute of Biochemistry, Justus-Liebig-University, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany
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49
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Van Goethem G, Martin JJ, Van Broeckhoven C. Progressive external ophthalmoplegia characterized by multiple deletions of mitochondrial DNA: unraveling the pathogenesis of human mitochondrial DNA instability and the initiation of a genetic classification. Neuromolecular Med 2003; 3:129-46. [PMID: 12835509 DOI: 10.1385/nmm:3:3:129] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2003] [Accepted: 03/19/2003] [Indexed: 12/15/2022]
Abstract
Over the last decade, many sporadic and familial cases have been reported with multiple deletions of mitochondrial DNA (mtDNA) in postmitotic tissues. Most patients suffer from progressive external ophthalmoplegia (PEO) and may have a nuclear gene defect that predisposes to the accumulation of mtDNA deletions. Recently, positional cloning has led to the discovery of mutations in four such nuclear genes. Some mutations are dominant and others recessive. In all autosomal mutations, defective mtDNA replication and/or repair are probably responsible for the generation of secondary mtDNA deletions. There are also data suggestive of a prominent pathogenic role for disturbed nucleotide metabolism. We here present a tentative genotype-phenotype correlation. Since clinical presentations are heterogeneous and overlap with different previously described clinical syndromes, we advocate the use of a genetic, instead of a clinical, classification of disorders with multiple mtDNA deletions.
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Affiliation(s)
- Gert Van Goethem
- Department of Molecular Genetics, Flanders Interuniversity Institute for Biotechnology (VIB), Born-Bunge Foundation (BBS), University of Antwerp (UIA), Antwerpen, Belgium
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Reyes A, Mezzina M, Gadaleta G. Human mitochondrial transcription factor A (mtTFA): gene structure and characterization of related pseudogenes. Gene 2002; 291:223-32. [PMID: 12095695 DOI: 10.1016/s0378-1119(02)00600-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Mitochondrial transcription factor A (mtTFA or Tfam) is a 25 kDa protein encoded by a nuclear gene and imported to mitochondria, where it functions as a key regulator of mammalian mitochondrial (mt) DNA transcription and replication. The coding sequence of the human mtTFA gene is reported in the literature and the sizes of few introns are known. In this paper we present the genomic structure of the human mtTFA gene along with the complete sequence of its six intronic regions. Three of the introns (I, III, VI) have been found to be less than 600 bp, while the other three were greater than 1.8 kb. In the course of this work, we discovered that, in addition to the active copy, different homologous sequences identified as processed pseudogenes psi h-mtTFA have been isolated and sequenced. Using an 'in silico' mapping approach we determined their locations on chromosomes 7, 11 and X. psi h-mtTFA locations are different from that of the gene, previously reported on chromosome 10. Transcription analysis by means of reverse transcriptase-polymerase chain reaction has shown that other than the RNA corresponding to the full-length transcript, an isoform lacking 96 bp is also present. Among the three sequenced pseudogenes only one of them located on chromosome 11 has been found to be transcribed in Jurkat cells under these culture conditions, even though transcription initiation and binding sites for different transcription factors have also been found upstream from the other two pseudogenes.
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Affiliation(s)
- Aurelio Reyes
- Centro di Studio sui Mitocondri e Metabolismo Energetico, CNR, via Amendola 165/A, 70126 Bari, Italy
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