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Zhang CJ, Mou H, Yuan J, Wang YH, Sun SN, Wang W, Xu ZH, Yu SJ, Jin K, Jin ZB. Effects of fluorescent protein tdTomato on mouse retina. Exp Eye Res 2024; 243:109910. [PMID: 38663720 DOI: 10.1016/j.exer.2024.109910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 02/26/2024] [Accepted: 04/22/2024] [Indexed: 04/30/2024]
Abstract
Fluorescent proteins (FPs) have been widely used to investigate cellular and molecular interactions and trace biological events in many applications. Some of the FPs have been demonstrated to cause undesirable cellular damage by light-induced ROS production in vivo or in vitro. However, it remains unknown if one of the most popular FPs, tdTomato, has similar effects in neuronal cells. In this study, we discovered that tdTomato expression led to unexpected retinal dysfunction and ultrastructural defects in the transgenic mouse retina. The retinal dysfunction mainly manifested in the reduced photopic electroretinogram (ERG) responses and decreased contrast sensitivity in visual acuity, caused by mitochondrial damages characterized with cellular redistribution, morphological modifications and molecular profiling alterations. Taken together, our findings for the first time demonstrated the retinal dysfunction and ultrastructural defects in the retinas of tdTomato-transgenic mice, calling for a more careful design and interpretation of experiments involved in FPs.
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Affiliation(s)
- Chang-Jun Zhang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Hao Mou
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Jing Yuan
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Ya-Han Wang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Shu-Ning Sun
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Wen Wang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Ze-Hua Xu
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Si-Jian Yu
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Kangxin Jin
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China.
| | - Zi-Bing Jin
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China.
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Tagliani S, Malaventura C, Ceccato C, Parmeggiani F, Suppiej A. Leber Mitochondrial Optic Neuropathy in Pediatric Females With Focus on Very Early Onset Cases. J Child Neurol 2023; 38:5-15. [PMID: 36659874 DOI: 10.1177/08830738221149962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The aim of this study was to describe the phenotype of Leber hereditary optic neuropathy occurring in pediatric females. This disease generally affects young adult males, but it can occur also in females, and research data in this population is lacking. The very early onset can challenge the diagnosis and delay treatment. We searched PubMed through February 2021 and identified 226 pediatric females with genetically confirmed Leber hereditary optic neuropathy and added a new case of a 3-year-old female. The male-female ratio was 1.8:1; the mean onset age in females was 11 years with the onset at 3 years of age occurring in 3 females only. Acute onset with mild visual impairment was the most common presentation, associated with optic disc edema in 16%. Differential diagnoses are pseudotumor cerebri, optic nerve drusen and optic neuritis. The outcome is poor with partial recovery in 50%, despite some receiving Idebenone therapy.
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Affiliation(s)
- Sara Tagliani
- Department of Medical Sciences, Pediatric Section, University Hospital of Ferrara, Ferrara, Italy
| | - Cristina Malaventura
- Department of Medical Sciences, Pediatric Section, University Hospital of Ferrara, Ferrara, Italy
| | | | - Francesco Parmeggiani
- Department of Translational Medicine and for Romagna, 9299University of Ferrara, Ferrara, Italy.,ERN-EYE Network - Center for Retinitis Pigmentosa of Veneto Region, 196013Camposampiero Hospital, Padova, Italy
| | - Agnese Suppiej
- Department of Medical Sciences, Pediatric Section, University Hospital of Ferrara, Ferrara, Italy.,87812Robert Hollman Foundation, Padova, Italy.,ERN-EYE Network - Center for Retinitis Pigmentosa of Veneto Region, 196013Camposampiero Hospital, Padova, Italy
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Moosa A, Ghani M, O'Neill HC. Genetic associations with polycystic ovary syndrome: the role of the mitochondrial genome; a systematic review and meta-analysis. J Clin Pathol 2022; 75:815-824. [DOI: 10.1136/jcp-2021-208028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 07/26/2022] [Indexed: 11/03/2022]
Abstract
BackgroundPolycystic ovary syndrome (PCOS) remains the most common female reproductive endocrine disorder. Genetic studies have predominantly focused on the role of the nuclear genome, while the contribution of mitochondrial genetics in PCOS remains largely unknown.AimThis study aims to systematically evaluate the literature regarding the associations between the mitochondrial genome and PCOS.MethodsA literature search focused on PCOS and mitochondrial genetics was conducted on (1) MEDLINE, (2) EMBASE and (3) The Cochrane Library (CENTRAL and Cochrane Reviews). Search results were screened for eligibility, and data involving genetic variants of mitochondrial DNA (mtDNA) were extracted. Quantitative data were presented in forest plots, and where this was not possible, data were analysed in a qualitative manner. Quality of studies was assessed using the Q-Genie tool.ResultsOf the 13 812 identified studies, 15 studies were eligible for inclusion, with 8 studies suitable for meta-analysis. Women with PCOS showed higher frequencies of a 9 bp deletion, and aberrant single nucleotide polymorphisms (SNPs) in the ND5, A6 and 7 transfer RNA-encoding genes. They also showed lower frequencies of two SNPs in the D-loop of the genome. Women with PCOS also exhibited significantly lowered mtDNA copy number.ConclusionWomen with PCOS harbour genetic variants in coding and non-coding regions of the mitochondrial genome. This may disrupt the electron transport chain and lead to oxidative stress, causing apoptosis of cells and further genetic damage. However, further studies of higher quality are required to confirm these associations.PROSPERO registration numberCRD42021267991.
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Jiang Z, Cai X, Kong J, Zhang R, Ding Y. Maternally transmitted diabetes mellitus may be associated with mitochondrial ND5 T12338C and tRNA Ala T5587C variants. Ir J Med Sci 2022; 191:2625-2633. [PMID: 34993838 DOI: 10.1007/s11845-021-02911-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 12/25/2021] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Mutations/variants in mitochondrial genomes are found to be associated with type 2 diabetes mellitus (T2DM), but the pathophysiology of this disease remains largely unknown. AIM The aim of this study is to investigate the relationship between mitochondrial DNA (mtDNA) variants and T2DM. METHODOLOGY A maternally inherited T2DM pedigree is underwent clinical, genetic, and molecular assessment. Moreover, the complete mitochondrial genomes of the matrilineal relatives of this family are PCR amplified and sequenced. We also utilize the phylogenetic conservation analysis, haplogroup classification, and the pathogenicity scoring system to determine the T2DM-associated potential pathogenic mtDNA variants. RESULT Four of seven matrilineal relatives of this pedigree suffered from T2DM with variable ages of onset. Screening for the entire mtDNA genes of matrilineal members reveals co-existence of ND5 T12338C and tRNAAla T5587C variants, as well as 21 genetic polymorphisms which belong to East Asian haplogroup F2. Interestingly, the T12338C variant causes the alternation of first amino acid Met to Thr, shortened two amino acids of ND5 protein. Furthermore, T5587C variant is located at position 73 in the 3'end of mt-tRNAAla and may have structural and functional consequences. CONCLUSIONS The co-occurrence of ND5 T12338C and tRNAAla T5587C variants may impair the mitochondrial function, which are associated with the development of T2DM in this family.
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Affiliation(s)
- Zhaochang Jiang
- Department of Pathology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaobo Cai
- Department of Pathology, Taizhou Central Hospital, Taizhou University Hospital, Taizhou, China
| | - Jing Kong
- Department of Endocrinology and Metabolism, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Ruyi Zhang
- Department of Pathology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Yu Ding
- Central Laboratory, Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China.
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Lin L, Zhang D, Jin Q, Teng Y, Yao X, Zhao T, Xu X, Jin Y. Mutational Analysis of Mitochondrial tRNA Genes in 200 Patients with Type 2 Diabetes Mellitus. Int J Gen Med 2021; 14:5719-5735. [PMID: 34557026 PMCID: PMC8454214 DOI: 10.2147/ijgm.s330973] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 08/25/2021] [Indexed: 12/12/2022] Open
Abstract
Objective Previous studies showed that variants in mitochondrial DNA (mtDNA) are associated with type 2 diabetes mellitus (T2DM). However, the relationships between mitochondrial tRNA (mt-tRNA) variants and T2DM remain poorly understood. Methods In this study, we performed a mutational screening of 22 mt-tRNA genes in a cohort of 200 Han Chinese subjects with T2DM and 200 control subjects through PCR–Sanger sequencing. The identified mt-tRNA variants were assessed for their pathogenicity via the phylogenetic approach, structural and functional analysis. Furthermore, two Han Chinese pedigrees with maternally inherited diabetes and deafness (MIDD) were reported by clinical and genetic assessments. Results A total of 49 genetic variants in mt-tRNA genes were identified; among them, 31 variants (17 pathogenic/likely pathogenic) were absent in controls, located at extremely conserved nucleotides, may have potential structural and functional significance, thereby considered to be T2DM-associated variants. In addition, sequence analysis of entire mitochondrial genomes of the matrilineal relatives from two MIDD pedigrees revealed the occurrence of tRNALeu(UUR) A3243G and T3290C mutations, as well as sets of polymorphisms belonging to mitochondrial haplogroups F2 and D4. However, the lack of any functional variants in connexin 26 gene (GJB2) and tRNA 5-methylaminomethyl-2-thiouridylate (TRMU) suggested that nuclear genes may not play active roles in clinical expression of MIDD in these pedigrees. Conclusion Our data indicated that mt-tRNA variants were associated with T2DM, screening for mt-tRNA pathogenic mutations was recommended for early detection and prevention of mitochondrial diabetes.
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Affiliation(s)
- Liangyan Lin
- Department of Endocrinology and Metabolism, Yantai Affiliated Hospital of Binzhou Medical University, Yantai, Shandong, People's Republic of China
| | - Dongdong Zhang
- Department of Endocrinology and Metabolism, Yantai Affiliated Hospital of Binzhou Medical University, Yantai, Shandong, People's Republic of China
| | - Qingsong Jin
- Department of Endocrinology and Metabolism, Yantai Affiliated Hospital of Binzhou Medical University, Yantai, Shandong, People's Republic of China
| | - Yaqin Teng
- Department of Endocrinology and Metabolism, Yantai Affiliated Hospital of Binzhou Medical University, Yantai, Shandong, People's Republic of China
| | - Xiaoyan Yao
- Department of Endocrinology and Metabolism, Yantai Affiliated Hospital of Binzhou Medical University, Yantai, Shandong, People's Republic of China
| | - Tiantian Zhao
- Department of Endocrinology and Metabolism, Yantai Affiliated Hospital of Binzhou Medical University, Yantai, Shandong, People's Republic of China
| | - Xinmiao Xu
- Department of Endocrinology, Yantai Yeda Hospital, Yantai, Shandong, People's Republic of China
| | - Yongjun Jin
- Department of Endocrinology and Metabolism, Yantai Affiliated Hospital of Binzhou Medical University, Yantai, Shandong, People's Republic of China
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Shuai J, Shi J, Liang Y, Ji F, Gu L, Yuan Z. Mutational analysis of mitochondrial tRNA genes in 138 patients with Leber's hereditary optic neuropathy. Ir J Med Sci 2021; 191:865-876. [PMID: 34053002 DOI: 10.1007/s11845-021-02656-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 05/19/2021] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Mutations in mitochondrial DNA (mtDNA) are the most important causes for Leber's hereditary optic neuropathy (LHON). Of these, three primary mtDNA mutations account for more than 90% cases of this disease. However, to date, little is known regarding the relationship between mitochondrial tRNA (mt-tRNA) variants and LHON. AIM In this study, we aimed to investigate the association between mt-tRNA variants and LHON. METHODOLOGY One hundred thirty-eight LHON patients lacking three primary mutations (ND1 3460G > A, ND4 11778Gxs > A, and ND6 14484 T > C), as well as 266 controls were enrolled in this study. PCR-Sanger sequencing was performed to screen the mt-tRNA variants. Moreover, the phylogenetic analysis, pathogenicity scoring system, as well as mitochondrial functions were performed. RESULTS We identified 8 possible pathogenic variants: tRNAPhe 593 T > C, tRNALeu(UUR) 3275C > T, tRNAGln 4363 T > C, tRNAMet 4435A > G, tRNAAla 5587 T > C, tRNAGlu 14693A > G, tRNAThr 15927G > A, and 15951A > G, which may change the structural and functional impact on the corresponding tRNAs, and subsequently lead to a failure in tRNA metabolism. Furthermore, significant reductions in mitochondrial ATP and MMP levels and an overproduction of ROS were observed in cybrid cells containing these mt-tRNA variants, suggesting that these variants may lead to mitochondrial dysfunction which was responsible for LHON. CONCLUSION Our study indicated that mt-tRNA variants were associated with LHON, and screening for mt-tRNA variants were recommended for early detection, diagnosis, and prevention of maternally inherited LHON.
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Affiliation(s)
- Jie Shuai
- Department of Ophthalmology, the Affiliated Hospital of Nantong University, Nantong, China
| | - Jian Shi
- Department of Ophthalmology, the Affiliated Hospital of Nantong University, Nantong, China
| | - Ya Liang
- Department of Ophthalmology, the First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, Jiangsu Province, China
| | - Fangfang Ji
- Department of Ophthalmology, the First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, Jiangsu Province, China
| | - Luo Gu
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Zhilan Yuan
- Department of Ophthalmology, the First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, Jiangsu Province, China.
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Ji Y, Zhang J, Lu Y, Yi Q, Chen M, Xie S, Mao X, Xiao Y, Meng F, Zhang M, Yang R, Guan MX. Complex I mutations synergize to worsen the phenotypic expression of Leber's hereditary optic neuropathy. J Biol Chem 2020; 295:13224-13238. [PMID: 32723871 DOI: 10.1074/jbc.ra120.014603] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/24/2020] [Indexed: 12/15/2022] Open
Abstract
Leber's hereditary optic neuropathy (LHON) is a maternal inheritance of eye disease because of the mitochondrial DNA (mtDNA) mutations. We previously discovered a 3866T>C mutation within the gene for the ND1 subunit of complex I as possibly amplifying disease progression for patients bearing the disease-causing 11778G>A mutation within the gene for the ND4 subunit of complex I. However, whether and how the ND1 mutation exacerbates the ND4 mutation were unknown. In this report, we showed that four Chinese families bearing both m.3866T>C and m.11778G>A mutations exhibited higher penetrances of LHON than 6 Chinese pedigrees carrying only the m.3866T>C mutation or families harboring only the m.11778G>A mutation. The protein structure analysis revealed that the m.3866T>C (I187T) and m.11778G>A (R340H) mutations destabilized the specific interactions with other residues of ND1 and ND4, thereby altering the structure and function of complex I. Cellular data obtained using cybrids, constructed by transferring mitochondria from the Chinese families into mtDNA-less (ρ°) cells, demonstrated that the mutations perturbed the stability, assembly, and activity of complex I, leading to changes in mitochondrial ATP levels and membrane potential and increasing the production of reactive oxygen species. These mitochondrial dysfunctions promoted the apoptotic sensitivity of cells and decreased mitophagy. Cybrids bearing only the m.3866T>C mutation displayed mild mitochondrial dysfunctions, whereas those harboring both m.3866T>C and m.11778G>A mutations exhibited greater mitochondrial dysfunctions. These suggested that the m.3866T>C mutation acted in synergy with the m.11778G>A mutation, aggravating mitochondrial dysfunctions and contributing to higher penetrance of LHON in these families carrying both mtDNA mutations.
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Affiliation(s)
- Yanchun Ji
- Department of Genetics and Metabolic Diseases, Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Division of Medical Genetics and Genomics, Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Juanjuan Zhang
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yuanyuan Lu
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Qiuzi Yi
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Mengquan Chen
- Department of Lab Medicine, Wenzhou Hospital of Traditional Chinese Medicine, Wenzhou, Zhejiang, China
| | - Shipeng Xie
- Department of Ophthalmology, Hebei Provincial Eye Hospital, Xingtai, Hebei, China
| | - Xiaoting Mao
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yun Xiao
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Feilong Meng
- Department of Genetics and Metabolic Diseases, Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Division of Medical Genetics and Genomics, Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Minglian Zhang
- Department of Ophthalmology, Hebei Provincial Eye Hospital, Xingtai, Hebei, China
| | - Rulai Yang
- Department of Genetics and Metabolic Diseases, Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
| | - Min-Xin Guan
- Division of Medical Genetics and Genomics, Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Key Lab of Reproductive Genetics, Ministry of Education of PRC, Zhejiang University, Hangzhou, Zhejiang, China; Joint Institute of Genetics and Genomic Medicine between Zhejiang University and University of Toronto, Hangzhou, Zhejiang, China.
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Ji Y, Zhang J, Yu J, Wang Y, Lu Y, Liang M, Li Q, Jin X, Wei Y, Meng F, Gao Y, Cang X, Tong Y, Liu X, Zhang M, Jiang P, Zhu T, Mo JQ, Huang T, Jiang P, Guan MX. Contribution of mitochondrial ND1 3394T>C mutation to the phenotypic manifestation of Leber's hereditary optic neuropathy. Hum Mol Genet 2020; 28:1515-1529. [PMID: 30597069 DOI: 10.1093/hmg/ddy450] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Revised: 11/05/2018] [Accepted: 12/22/2018] [Indexed: 11/14/2022] Open
Abstract
Mitochondrial DNA (mtDNA) mutations have been associated with Leber's hereditary optic neuropathy (LHON) and their pathophysiology remains poorly understood. In this study, we investigated the pathophysiology of a LHON susceptibility allele (m.3394T>C, p.30Y>H) in the Mitochondrial (MT)-ND1 gene. The incidence of m.3394T>C mutation was 2.7% in the cohort of 1741 probands with LHON. Extremely low penetrances of LHON were observed in 26 pedigrees carrying only m.3394T>C mutation, while 21 families bearing m.3394T>C, together with m.11778G>A or m.14484T>C mutation, exhibited higher penetrance of LHON than those in families carrying single mtDNA mutation(s). The m.3394T>C mutation disrupted the specific electrostatic interactions between Y30 of p.MT-ND1 with the sidechain of E4 and backbone carbonyl group of M1 of NDUFA1 (NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 1) of complex I, thereby altering the structure and function of complex I. We demonstrated that these cybrids bearing only m.3394T>C mutation caused mild mitochondrial dysfunctions and those harboring both m.3394T>C and m.11778G>A mutations exhibited greater mitochondrial dysfunctions than cybrids carrying only m.11778G>A mutation. In particular, the m.3394T>C mutation altered the stability of p.MT-ND1 and complex I assembly. Furthermore, the m.3394T>C mutation decreased the activities of mitochondrial complexes I, diminished mitochondrial ATP levels and membrane potential and increased the production of reactive oxygen species in the cybrids. These m.3394T>C mutation-induced alterations aggravated mitochondrial dysfunctions associated with the m.11778G>A mutation. These resultant biochemical defects contributed to higher penetrance of LHON in these families carrying both mtDNA mutations. Our findings provide new insights into the pathophysiology of LHON arising from the synergy between mitochondrial ND1 and ND4 mutations.
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Affiliation(s)
- Yanchun Ji
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Juanjuan Zhang
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jialing Yu
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Ying Wang
- Department of Ophthalmology, Chinese Academy of Traditional Chinese Medicine, Beijing, China
| | - Yuanyuan Lu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Min Liang
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Qiang Li
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xiaofen Jin
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yinsheng Wei
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Feilong Meng
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yinglong Gao
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xiaohui Cang
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yi Tong
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Xiaoling Liu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Minglian Zhang
- Department of Ophthalmology, Hebei Provincial Eye Hospital, Xingtai, Hebei, China
| | - Peifang Jiang
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Tao Zhu
- Department of Critical Care Medicine, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Jun Qin Mo
- Department of Pathology, Rady Children's Hospital, University of California School of Medicine, San Diego, California, USA
| | - Taosheng Huang
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Pingping Jiang
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Min-Xin Guan
- Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Key Lab of Reproductive Genetics, Ministry of Education of PRC, Zhejiang University, Hangzhou, China.,Joint Institute of Genetics and Genomic Medicine between Zhejiang University and University of Toronto, Hangzhou, Zhejiang, China
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Gao Z, Yuan YS. Screening for mitochondrial 12S rRNA C1494T mutation in 655 patients with non-syndromic hearing loss: An observational study. Medicine (Baltimore) 2020; 99:e19373. [PMID: 32221064 PMCID: PMC7220552 DOI: 10.1097/md.0000000000019373] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Mutations in mitochondrial DNA, especially in 12S rRNA gene, are the most important causes for hearing loss. In particular, the A1555G and C1494T mutations have been found to be associated with both aminoglycoside-induced and non-syndromic hearing loss in many families worldwide. To determine the frequency of C1494T mutation in deaf patients, in the current study, we screened this mutation in 655 patients with non-syndromic hearing loss and 300 control subjects. After PCR amplification of mitochondrial 12S rRNA gene and direct sequence analysis, we found that there were 2 patients carrying the C1494T mutation; however, this mutation was not detected in 300 healthy subjects. Further genetic counseling suggested that only 1 patient had an obvious family history of hearing impairment. Clinical evaluation showed that 3 of 10 matrilineal relatives suffered from hearing loss, with different age at onset of hearing loss. Molecular analysis revealed the presence of homoplasmic 12S rRNA C1494T and ND5 T12338C mutations, together with a set of polymorphisms belonging to human mitochondrial haplogroup F2. Interestingly, T12338C mutation resulted in the replacement of the first amino acid, a translation-initiating methionine with a threonine, shortening 2 amino acids of ND5 polypeptide. Moreover, this mutation is located in 2 nucleotides adjacent to the 3' end of the mt-tRNALeu(CUN) gene. Therefore, this mutation may alter ND5 mRNA metabolism and the processing of RNA precursors. Thus, the combination of T12338C and C1494T mutations may contribute to deafness expression in this family. Taken together, our data suggested that the C1494T mutation was the molecular basis for hearing loss, screening for the mitochondrial DNA pathogenic mutations was recommended for early detection, prevention, and diagnosis of mitochondrial deafness.
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Affiliation(s)
- Zhen Gao
- Department of Otology and Skull Base Surgery, Eye & ENT Hospital
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, China
| | - Ya-Sheng Yuan
- Department of Otology and Skull Base Surgery, Eye & ENT Hospital
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, China
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10
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Sun D, Wei Y, Zheng HX, Jin L, Wang J. Contribution of Mitochondrial DNA Variation to Chronic Disease in East Asian Populations. Front Mol Biosci 2019; 6:128. [PMID: 31803756 PMCID: PMC6873657 DOI: 10.3389/fmolb.2019.00128] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 10/29/2019] [Indexed: 12/17/2022] Open
Abstract
Mitochondria are the main producers of energy in eukaryotic cells. Mitochondrial dysfunction is associated with specific mitochondrial DNA (mtDNA) variations (haplogroups), and these variations can contribute to human disease. East Asian populations show enrichment of many mitochondrial haplogroups, including A, B, D, G, M7, M8, M9, N9, R9, and exhibit half of the known haplogroups of worldwide. In this review, we summarize the current research in the field of mtDNA variation and associated disease in East Asian populations and discuss the physiological and pathological relevance of mitochondrial biology. mtDNA haplogroups are associated with various metabolic disorders ascribed to altered oxidative phosphorylation. The same mitochondrial haplogroup can show either a negative or positive association with different diseases. Mitochondrial dynamics, mitophagy, and mitochondrial oxidative stress, ultimately influence susceptibility to various diseases. In addition, mitochondrial retrograde signaling pathways may have profound effects on nuclear-mitochondrial interactions, affecting cellular morphology, and function. Other complex networks including proteostasis, mitochondrial unfolded protein response and reactive oxygen species signaling may also play pivotal roles in metabolic performance.
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Affiliation(s)
- Dayan Sun
- State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.,Human Phenome Institute, Fudan University, Shanghai, China
| | - Yang Wei
- State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.,Human Phenome Institute, Fudan University, Shanghai, China
| | - Hong-Xiang Zheng
- Ministry of Education Key Laboratory of Contemporary Anthropology, Department of Anthropology and Human Genetics, School of Life Sciences, Fudan University, Shanghai, China
| | - Li Jin
- State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.,Human Phenome Institute, Fudan University, Shanghai, China
| | - Jiucun Wang
- State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.,Human Phenome Institute, Fudan University, Shanghai, China
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11
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Singh RK, Saini SK, Prakasam G, Kalairasan P, Bamezai RNK. Role of ectopically expressed mtDNA encoded cytochrome c oxidase subunit I (MT-COI) in tumorigenesis. Mitochondrion 2019; 49:56-65. [PMID: 31299394 DOI: 10.1016/j.mito.2019.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 05/17/2019] [Accepted: 07/03/2019] [Indexed: 11/30/2022]
Abstract
Somatic mutations within mitochondrial DNA (mtDNA) encoded cytochrome c oxidase subunit I (MT-CO1 or MT-COI) are frequent in various cancer types. In addition, perturbation from orchestrated expression of mitochondrial DNA encoded genes is also associated with complex disorders, including cancer. Since codon bias and the mitochondrial translation system restricts functional characterization of over-expressed wild type or mutant mitochondrial DNA encoded genes, the codon optimization and artificial synthesis of entire MT-CO1 allowed us to over-express the wild type and one of its deleterious mutants into the mitochondria of the transfected cells. Ectopically expressed MT-CO1 was observed to efficiently express and localized to mitochondria but showed high level of aggregation under denaturing condition. Over-expression of wild type or mutant variant of MT-CO1 promoted anchorage dependent and independent proliferation potential in in-vitro experiments and introduced the cancer cell metabolic phenotype of high glucose uptake and lactate release. Reactive oxygen species generated in cells over-expressing MT-CO1 variants acted as key effectors mediating differential expression of apoptosis and DNA damage pathway related genes. High ROS generated also down-regulated the expression of global regulators of gene expression, DNMT3A and DNMT3B. The down-regulated expression of DNMTs co-related with differential methylation of the CpG islands in the promoter region of a select set of studied genes, in a manner to promote pro-cancerous phenotype. Apart from assigning the mechanistic role to the MT-CO1 variants and their perturbed expression in cancer development, the present study provides novel insights into the functional role of somatic mutations within MT-CO1 promoting cancer phenotype.
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Affiliation(s)
- Rajnish Kumar Singh
- National Centre of Applied Human Genetics, School of life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
| | - Sunil Kumar Saini
- National Centre of Applied Human Genetics, School of life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Gopinath Prakasam
- National Centre of Applied Human Genetics, School of life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Ponnuusamy Kalairasan
- National Centre of Applied Human Genetics, School of life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Rameshwar N K Bamezai
- National Centre of Applied Human Genetics, School of life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
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12
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Lyu Y, Xu M, Chen J, Ji Y, Guan MX, Zhang J. Frequency and spectrum of MT-TT variants associated with Leber's hereditary optic neuropathy in a Chinese cohort of subjects. MITOCHONDRIAL DNA PART B-RESOURCES 2019; 4:2266-2280. [PMID: 33365504 PMCID: PMC7687527 DOI: 10.1080/23802359.2019.1627921] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Leber’s hereditary optic neuropathy (LHON) is a maternally inherited eye disease. In our previous investigations, we have reported the spectrum and frequency of mitochondrial MT-ND1, MT-ND4 and MT-ND6 gene in Chinese LHON population. This study aimed to assess the molecular epidemiology of MT-TT mutations in Chinese families with LHON. A cohort of 352 Chinese Han probands lacking the known LHON-associated mtDNA mutations and 376 control subjects underwent molecular analysis of mtDNA. All variants were evaluated for evolutionary conservation, structural and functional consequences. Fifteen variants were identified in the MT-TT gene by mitochondrial genome analysis of LHON pedigrees, which was substantially higher than that of individuals from general Chinese populations. The incidences of the two known LHON-associated mutations, m.15927G > A and m.15951A > G, were 2.27% and 1.14%, respectively. Nine putative LHON-associated variants were identified in 20 probands, translated into 2.1% cases of this cohort. Moreover, mtDNAs in 41 probands carrying the MT-TT mutation(s) were widely dispersed among nine Eastern Asian haplogroups. Our results suggest that the MT-TT gene is a mutational hotspot for these 352 Chinese families lacking the known LHON-associated mutations. These data further showed the molecular epidemiology of MT-TT mutations in Chinese Han LHON pedigrees.
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Affiliation(s)
- Yuanyuan Lyu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,School of Laboratory Medicine and Life Sciences, Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Man Xu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,School of Laboratory Medicine and Life Sciences, Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jie Chen
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,School of Laboratory Medicine and Life Sciences, Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - YanChun Ji
- School of Medicine, Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China
| | - Min-Xin Guan
- School of Laboratory Medicine and Life Sciences, Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China.,School of Medicine, Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China
| | - Juanjuan Zhang
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,School of Laboratory Medicine and Life Sciences, Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
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13
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Zhang J, Ji Y, Lu Y, Fu R, Xu M, Liu X, Guan MX. Leber's hereditary optic neuropathy (LHON)-associated ND5 12338T > C mutation altered the assembly and function of complex I, apoptosis and mitophagy. Hum Mol Genet 2019; 27:1999-2011. [PMID: 29579248 DOI: 10.1093/hmg/ddy107] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 03/19/2018] [Indexed: 02/04/2023] Open
Abstract
Mutations in mitochondrial DNA (mtDNA) have been associated with Leber's hereditary optic neuropathy (LHON) and their pathophysiology remains poorly understood. In this study, we demonstrated that a missense mutation (m.12338T>C, p.1M>T) in the ND5 gene contributed to the pathogenesis of LHON. The m.12338T>C mutation affected the first methionine (Met1) with a threonine and shortened two amino acids of ND5. We therefore hypothesized that the mutated ND5 perturbed the structure and function of complex I. Using the cybrid cell models, generated by fusing mtDNA-less (ρ°) cells with enucleated cells from LHON patients carrying the m.12338T>C mutation and a control subject belonging to the same mtDNA haplogroup, we demonstrated that the m.12338T>C mutation caused the reduction of ND5 polypeptide, perturbed assemble and activity of complex I. Furthermore, the m.12338T>C mutation caused respiratory deficiency, diminished mitochondrial adenosine triphosphate levels and membrane potential and increased the production of reactive oxygen species. The m.12338T>C mutation promoted apoptosis, evidenced by elevated release of cytochrome c into cytosol and increased levels of apoptosis-activated proteins: caspases 9, 3, 7 and Poly ADP ribose polymerase in the cybrids carrying the m.12338T>C mutation, as compared with control cybrids. Moreover, we also document the involvement of m.12338T>C mutation in decreased mitophagy, as showed by reduced levels of autophagy protein light chain 3 and accumulation of autophagic substrate p62 in the in mutant cybrids as compared with control cybrids. These data demonstrated the direct link between mitochondrial dysfunction caused by complex I mutation and apoptosis or mitophagy. Our findings may provide new insights into the pathophysiology of LHON.
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Affiliation(s)
- Juanjuan Zhang
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310052, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang 325600, China.,Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical College, Wenzhou, Zhejiang 325035, China
| | - Yanchun Ji
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310052, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Yuanyuan Lu
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang 325600, China.,Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical College, Wenzhou, Zhejiang 325035, China
| | - Runing Fu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang 325600, China.,Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical College, Wenzhou, Zhejiang 325035, China
| | - Man Xu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang 325600, China.,Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical College, Wenzhou, Zhejiang 325035, China
| | - Xiaoling Liu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang 325600, China.,Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical College, Wenzhou, Zhejiang 325035, China
| | - Min-Xin Guan
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310052, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang 325600, China.,Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical College, Wenzhou, Zhejiang 325035, China.,Joint Institute of Genetics and Genome Medicine between Zhejiang University and University of Toronto, Hangzhou, Zhejiang, China
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14
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Ilie IR. Advances in PCOS Pathogenesis and Progression-Mitochondrial Mutations and Dysfunction. Adv Clin Chem 2018; 86:127-155. [PMID: 30144838 DOI: 10.1016/bs.acc.2018.05.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Polycystic ovary syndrome (PCOS) is a common female endocrine disorder, which still remains largely unsolved in terms of etiology and pathogenesis despite important advances in our understanding of its genetic, epigenetic, or environmental factor implications. It is a heterogeneous disease, frequently associated with insulin resistance, chronic inflammation, and oxidative stress and probably accompanied with subclinical cardiovascular disease (CVD) and some malignant lesions as well, such as endometrial cancer. Discrepancies in the clinical phenotype and progression of PCOS exist between different population groups, which nuclear genetic studies have so far failed to explain. Over the last years, mitochondrial dysfunction has been increasingly recognized as an important contributor to an array of diseases. Because mitochondria are under the dual genetic control of both the mitochondrial and nuclear genomes, mutations within either DNA molecule may result in deficiency in respiratory chain function that leads to a reduced ability to produce cellular adenosine-5'-triphosphate and to an excessive production of reactive oxygen species. However, the association between variants in mitochondrial genome, mitochondrial dysfunction, and PCOS has been investigated to a lesser extent. May mutations in mitochondrial DNA (mtDNA) become an additional target of investigations on the missing PCOS heritability? Are mutations in mtDNA implicated in the initiation and progression of PCOS complications, e.g., CVDs, diabetes mellitus, cancers?
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Affiliation(s)
- Ioana R Ilie
- Department of Endocrinology, University of Medicine and Pharmacy 'Iuliu-Hatieganu', Cluj-Napoca, Romania; E-mail:
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15
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Zhang J, Ji Y, Liu X, Chen J, Wang B, Zhang M, Guan MX. Leber's hereditary optic neuropathy caused by a mutation in mitochondrial tRNA Thr in eight Chinese pedigrees. Mitochondrion 2017; 42:84-91. [PMID: 29225014 DOI: 10.1016/j.mito.2017.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 11/09/2017] [Accepted: 12/06/2017] [Indexed: 01/09/2023]
Abstract
PURPOSE The purpose of this study was to investigate the pathophysiology underlying Leber's hereditary optic neuropathy (LHON)-associated mitochondrial tRNA mutation. METHODS Severn hundred ninety-seven Han Chinese subjects underwent clinical and genetic evaluation and analysis of mitochondrial DNA (mtDNA). The cybrid cell lines were constructed by transferring mitochondria from lymphoblastoid cell lines derived from a Chinese family into mtDNA-less (ρo) cells. These cell lines were assayed by tRNA Northern blot and Western blot analyses, respiratory enzymatic activities, the rate of ATP production and the generation of reactive oxygen species. RESULTS The tRNAThr 15927G>A mutation was identified in eight probands with suggestively maternal inheritance among 352 Han Chinese probands lacking these known LHON-associated mtDNA mutations. The m.15927G>A mutation affected a highly conserved guanine at position 42 at the anticodon-stem of tRNAThr, destabilizing the conservative base pairing (28C-42G). We therefore hypothesized that the m.15927G>A mutation, and altered the structure and function of tRNAThr. Northern blot analysis revealed 60% decrease in the steady-state level of tRNAThr in the mutant cell lines. Western blot analysis showed the variable reductions of 4 mtDNA encoding proteins, especially for marked decrease of ND1 and CYTB observed in mutant cell lines. Furthermore, we demonstrated that the m.15927G>A mutation decreased the activities of mitochondrial complexes I and III, markedly diminished mitochondrial ATP levels, and increased the production of reactive oxygen species in the mutant cells. CONCLUSIONS Our data demonstrated the first mitochondrial tRNA mutation leading to LHON. Our findings may provide new insights into the understanding of pathophysiology of LHON.
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Affiliation(s)
- Juanjuan Zhang
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China; Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yanchun Ji
- Division of Medical Genetics and Genomics, Zhejiang Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xiaoling Liu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jie Chen
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Bibin Wang
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Minglian Zhang
- Department of Ophthalmology, Hebei Provincial Eye Hospital, Xingtai, Hebei, China
| | - Min-Xin Guan
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China; Division of Medical Genetics and Genomics, Zhejiang Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Department of Ophthalmology, Hebei Provincial Eye Hospital, Xingtai, Hebei, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou, China.
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16
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Ji Y, Qiao L, Liang X, Zhu L, Gao Y, Zhang J, Jia Z, Wei QP, Liu X, Jiang P, Guan MX. Leber's hereditary optic neuropathy is potentially associated with a novel m.5587T>C mutation in two pedigrees. Mol Med Rep 2017; 16:8997-9004. [PMID: 28990081 DOI: 10.3892/mmr.2017.7734] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 07/21/2017] [Indexed: 12/17/2022] Open
Abstract
Mitochondrial (mt)DNA mutations have been revealed to be associated with Leber's hereditary optic neuropathy (LHON). The present study conducted clinical, genetic and molecular evaluations of two Han Chinese families. A total of 4 (3 men and 1 female) out of 14 matrilineal relatives in the families exhibited visual impairment with variable severity and age of onset. The average age of onset of visual loss was 20.5 years old. Molecular analysis of the complete mitochondrial genome in these pedigrees demonstrated that the three primary mutations associated with LHON were not detected; however, the homoplasmic m.5587T>C mutation was identified, which was localized at the end of the mitochondrially encoded transfer (t)RNA alanine gene and may alter the tertiary structure of this tRNA. Subsequently, this structural alteration may result in tRNA metabolism failure. In addition, distinct sets of mtDNA polymorphisms belonging to haplogroup F1 were detected in both families tested. The findings of the present study suggested that the m.5587T>C mutation may be involved in the pathogenesis of visual impairment. In addition, the mtDNA variant m.15024G>A(p.C93H) in the mitochondrially encoded cytochrome B gene was detected in both families, which exhibited evolutionary conservation, indicating it may serve a potential modifying role in the development of visual impairment associated with m.5587T>C mutation in these families. Furthermore, other modifying factors, including nuclear modifier genes, and environmental and personal factors may also contribute to the development of LHON in subjects carrying this mutation.
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Affiliation(s)
- Yanchun Ji
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Lihua Qiao
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Xiaoyang Liang
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Ling Zhu
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Yinglong Gao
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Juanjuan Zhang
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang 325025, P.R. China
| | - Zidong Jia
- Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Qi-Ping Wei
- Department of Ophthalmology, Beijing University of Chinese Medicine, Beijing 100029, P.R. China
| | - Xiaoling Liu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang 325025, P.R. China
| | - Pingping Jiang
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Min-Xin Guan
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
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17
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Mitochondrial ND5 mutation mediated elevated ROS regulates apoptotic pathway epigenetically in a P53 dependent manner for generating pro-cancerous phenotypes. Mitochondrion 2017; 35:35-43. [PMID: 28502718 DOI: 10.1016/j.mito.2017.05.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 05/02/2017] [Accepted: 05/08/2017] [Indexed: 11/23/2022]
Abstract
We have previously observed concomitant events of mutations in mitochondrial and nuclear genes, along with elevated reactive oxygen species (ROS) and differential methylation within the promoters of nuclear genes in tumors and in vitro experiments of tumorigenesis. These observations have made it pertinent to replicate and understand the role of acquired mitochondrial condition in tuning a cell to accomplish a pro-cancerous state. Using a codon optimized vector system for exogenous over-expression and mitochondrial localization; we have characterized here the role of over-expressed wild type mtND5 and one of its non-synonymous somatic mutation, ND5:P265H. The ectopically over-expressed ND5:P265H in mitochondria resulted in a reduced Complex I activity, generation of higher ADP/ATP ratio, reactive oxygen species (ROS) and carbonylation of proteins as compared to mock-transfected cells. Cells over-expressing mtND5 variant produced both peroxide as well as super-oxide ROS; the generation of which was dependent on the functional status of P53; modulating epigenetically the expression of key apoptosis pathway genes. The pro-cancerous phenotypes, of anchorage dependent and independent growth; increased glucose uptake and lactate production, were selectively observed only in P53 non-functional cells over-expressing mutant ND5:P265H. We propose that somatic mutation in mtND5 resulting in down-regulated complex I enzyme activity, elevated ROS and up-regulation of a set of nuclear anti-apoptotic genes epigenetically in the P53 dysfunctional cellular background, has provided a unique understanding of the molecular mechanism of mitochondrial mutation; and the concomitant existence of somatically acquired mitochondrial and nuclear p53 mutations, in cancer progression and promotion.
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18
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Ding Y, Zhuo G, Zhang C, Leng J. Point mutation in mitochondrial tRNA gene is associated with polycystic ovary syndrome and insulin resistance. Mol Med Rep 2016; 13:3169-72. [PMID: 26935780 DOI: 10.3892/mmr.2016.4916] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 01/20/2016] [Indexed: 11/06/2022] Open
Abstract
Polycystic ovarian syndrome (PCOS) is characterized by chronic anovulation, hyperandrogenism and polycystic ovaries. To date, the molecular mechanisms underlying PCOS have remained to be fully elucidated. As recent studies have revealed a positive association between mitochondrial dysfunction and PCOS, current investigations focus on mutations in the mitochondrial genome of patients with POCS. The present study reported a Chinese patient with PCOS. Sequence analysis of the mitochondrial genome showed the presence of homoplasmic ND5 T12338C and tRNASer (UCN) C7492T mutations as well as a set of polymorphisms belonging to the human mitochondrial haplogroup F2. The T12338C mutation is known to decrease the ND5 mRNA levels and to inhibit the processing of RNA precursors. The C7492T mutation, which occurred at the highly conserved nucleotide in the anticodon stem of the tRNASer (UCN) gene, is important for the tRNA steady‑state level as well as the aminoacylation ability. Therefore, the combination of the ND5 T12338C and tRNASer (UCN) C7492T mutations may lead to mitochondrial dysfunction, and is likely to be involved in the pathogenesis of PCOS. The present study provided novel insight into the molecular mechanisms of PCOS.
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Affiliation(s)
- Yu Ding
- Central Laboratory, Hangzhou First People's Hospital Affiliated to Nanjing Medical University, Hangzhou, Zhejiang 310006, P.R. China
| | - Guangchao Zhuo
- Central Laboratory, Hangzhou First People's Hospital Affiliated to Nanjing Medical University, Hangzhou, Zhejiang 310006, P.R. China
| | - Caijuan Zhang
- Central Laboratory, Hangzhou First People's Hospital Affiliated to Nanjing Medical University, Hangzhou, Zhejiang 310006, P.R. China
| | - Jianhang Leng
- Central Laboratory, Hangzhou First People's Hospital Affiliated to Nanjing Medical University, Hangzhou, Zhejiang 310006, P.R. China
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19
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Zhang J, Jiang P, Jin X, Liu X, Zhang M, Xie S, Gao M, Zhang S, Sun YH, Zhu J, Ji Y, Wei QP, Tong Y, Guan MX. Leber's hereditary optic neuropathy caused by the homoplasmic ND1 m.3635G>A mutation in nine Han Chinese families. Mitochondrion 2014; 18:18-26. [PMID: 25194554 DOI: 10.1016/j.mito.2014.08.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 08/28/2014] [Accepted: 08/29/2014] [Indexed: 11/18/2022]
Abstract
In this report, we investigated the molecular mechanism underlying Leber's hereditary optic neuropathy (LHON)-associated mitochondrial m.3635G>A (p.S110N, ND1) mutation. A mutational screening of ND1 gene in a cohort of 1070 Han Chinese subjects LHON identified the m.3635G>A mutation in nine Chinese families with suggestively maternally transmitted LHON. Thirty-eight (22 males/16 females) of 162 matrilineal relatives in these families exhibited the variable severity and age-at-onset of optic neuropathy. Molecular analysis of their mitochondrial genomes identified the homoplasmic m.3635G>A mutation and distinct sets of polymorphisms belonging to the Asian haplogroups G2a1, R11a, D4, R11a, M7b2, G1a, F1a1, B4, and N9a3, respectively. Using cybrids constructed by transferring mitochondria from lymphoblastoid cell lines derived from one Chinese family into mtDNA-less (ρ(0)) cells, we showed ~27% decrease in the activity of NADH:ubiquinone oxidoreductase (complex I) in mutant cybrids carrying the m.3635G>A mutation, compared with control cybrids. The respiratory deficiency caused by the m.3635G>A mutation results in decreased efficiency of mitochondrial ATP synthesis. These mitochondrial dysfunctions caused an increase in the production of reactive oxygen species in the mutant cybrids. The data provide the direct evidence for the m.3635G>A mutation leading to LHON. Our findings may provide new insights into the understanding of pathophysiology of LHON.
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Affiliation(s)
- Juanjuan Zhang
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China; School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Pingping Jiang
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaofen Jin
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaoling Liu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China; Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Minglian Zhang
- Department of Ophthalmology, Hebei Provincial Eye Hospital, Xingtai, Hebei, China
| | - Shipeng Xie
- Department of Ophthalmology, Hebei Provincial Eye Hospital, Xingtai, Hebei, China
| | - Min Gao
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China; Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Sai Zhang
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China; Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yan-Hong Sun
- Department of Ophthalmology, Beijing University of Chinese Medicine and Pharmacology, Beijing, China
| | - Jinping Zhu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China; Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yanchun Ji
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China
| | - Qi-Ping Wei
- Department of Ophthalmology, Beijing University of Chinese Medicine and Pharmacology, Beijing, China
| | - Yi Tong
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Min-Xin Guan
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China; Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China.
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20
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Ma YY, Wu TF, Liu YP, Wang Q, Li XY, Ding Y, Song JQ, Yang YL, Zou LP. A study of 133 Chinese children with mitochondrial respiratory chain complex I deficiency. Clin Genet 2014; 87:179-84. [PMID: 24502327 DOI: 10.1111/cge.12356] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 02/01/2014] [Accepted: 02/04/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Y.-Y. Ma
- Department of Pediatrics; Chinese Liberation Army General Hospital; Beijing China
| | - T.-F. Wu
- Department of Pediatrics; Peking University First Hospital; Beijing China
| | - Y.-P. Liu
- Department of Pediatrics; Peking University First Hospital; Beijing China
| | - Q. Wang
- Department of Pediatrics; Peking University First Hospital; Beijing China
| | - X.-Y. Li
- Department of Pediatrics; Peking University First Hospital; Beijing China
| | - Y. Ding
- Department of Pediatrics; Peking University First Hospital; Beijing China
| | - J.-Q. Song
- Department of Pediatrics; Peking University First Hospital; Beijing China
| | - Y.-L. Yang
- Department of Pediatrics; Peking University First Hospital; Beijing China
| | - L.-P. Zou
- Department of Pediatrics; Chinese Liberation Army General Hospital; Beijing China
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21
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Ma YY, Wu TF, Liu YP, Wang Q, Song JQ, Li XY, Shi XY, Zhang WN, Zhao M, Hu LY, Yang YL, Zou LP. Genetic and biochemical findings in Chinese children with Leigh syndrome. J Clin Neurosci 2013; 20:1591-4. [PMID: 23953430 DOI: 10.1016/j.jocn.2013.03.034] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2012] [Revised: 03/19/2013] [Accepted: 03/24/2013] [Indexed: 01/30/2023]
Abstract
This study investigated the genetic and enzymological features of Leigh syndrome due to respiratory chain complex deficiency in Chinese patients. The clinical features of 75 patients were recorded. Mitochondrial respiratory chain enzyme activities were determined via spectrophotometry. Mitochondrial gene sequence analysis was performed in 23 patients. Five core pedigrees were investigated via restriction fragment length polymorphism and gene sequencing. Psychomotor retardation (55%), motor regression (20%), weakness (29%), and epilepsy (25%) were the most frequent manifestations. Sixty-four patients (85.3%) had isolated respiratory complex deficiencies: complex I was seen in 28 patients (37.3%); complex II, seven (9.3%); complex III, six (8%); complex IV, ten (13.3%); and complex V, 13 patients (17.3%). Eleven patients (14.7%) had combined complex deficiencies. Mitochondrial DNA mutations were detected in 10 patients. Eight point mutations were found in mitochondrial structural genes: m.4833A>G in ND2, m.10191T>C in ND3, m.12338T>C and m.13513G>A in ND5, m.14502T>C and m.14487T>C in ND6, m.8108A>G in COXII, and m.8993T>G in ATPase6. Three mutations were found in tRNA genes: m.4395A>G in tRNA-Gln, m.10454T>C in tRNA-Arg, and m.5587T>C in tRNA-Ala. One patient and their mother both had the m.12338T>C and m.8993T>C mutations. In conclusion, mitochondrial respiratory chain complex I deficiency and structural gene mutations frequently occur in Chinese Leigh syndrome patients.
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Affiliation(s)
- Yan-Yan Ma
- Department of Pediatrics, Chinese Liberation Army General Hospital, No. 28 Fu-xing Road, Haidian District, Beijing 100853, People's Republic of China
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22
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Teng L, Zheng J, Leng J, Ding Y. Clinical and molecular characterization of a Han Chinese family with high penetrance of essential hypertension. ACTA ACUST UNITED AC 2012; 23:461-5. [PMID: 22917175 DOI: 10.3109/19401736.2012.710205] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Mutations in mitochondrial DNA are associated with cardiovascular diseases. We reported here molecular characterization of a three-generation Han Chinese family with maternally transmitted hypertension. Most strikingly, this family exhibited a high penetrance of hypertension. Sequence analysis of mitochondrial genome showed the presence of 12,338T>C mutation and 12,330A>G mutation and distinct sets of polymorphisms belonging to the Asian haplogroup F2b. Interestingly, the well-known 12,338T>C mutation, which caused a change of methionine in the translational initiation codon of ND5, also localized in two nucleotides adjacent to the 3' end of tRNA(Leu(CUN)), was implied to cause a decrease in ND5 mRNA level as well as to alter tRNA(Leu(CUN)) stability level. Moreover, the highly conserved 12,330A>G mutation, which disrupted the base pairing (6T-67A) in acceptor arm of tRNA(Leu(CUN)), may result in the failure of tRNA(Leu(CUN)) metabolism. Therefore, the combination of ND5 12,338T>C and tRNA(Leu(CUN)) 12,330A>G mutations may contribute to the high penetrance of hypertension in this Chinese family.
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Affiliation(s)
- Lili Teng
- Department of Geriatric Medicine, Shanghai East Hospital, Tongji University, Shanghai, PR China
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23
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Ding D, Scott NM, Thompson EE, Chaiworapongsa T, Torres R, Billstrand C, Murray K, Dexheimer PJ, Ismail M, Kay H, Levy S, Romero R, Lindheimer MD, Nicolae DL, Ober C. Increased protein-coding mutations in the mitochondrial genome of African American women with preeclampsia. Reprod Sci 2012; 19:1343-51. [PMID: 22902742 DOI: 10.1177/1933719112450337] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Preeclampsia occurs more frequently in women of African ancestry. The cause of this hypertensive complication is unclear, but placental oxidative stress may play a role. Because mitochondria are the major sites of oxidative phosphorylation, we hypothesized that placentas of preeclamptic pregnancies harbor mitochondrial DNA (mtDNA) mutations. Next-generation sequencing of placental mtDNA in African American preeclamptics (N = 30) and controls (N = 38) from Chicago revealed significant excesses in preeclamptics of nonsynonymous substitutions in protein-coding genes and mitochondrially encoded nicotinamide adenine dinucleotide dehydrogenase 5 gene and an increase in the substitution rate (P = .0001). Moreover, 88% of preeclamptics and 53% of controls carried at least one nonsynonymous substitution (P = .005; odds ratio [OR] = 6.36, 95% confidence interval [CI]: 1.5-39.1). These results were not replicated in a sample of African American preeclamptics (N = 162) and controls (N = 171) from Detroit. Differences in study design and heterogeneity may account for this lack of replication. Nonsynonymous substitutions in mtDNA may be risk factors for preeclampsia in some African American women, but additional studies are required to establish this relationship.
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Affiliation(s)
- David Ding
- Department of Obstetrics and Gynecology, The University of Chicago, Chicago, IL 60637, USA
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Zhou X, Qian Y, Zhang J, Tong Y, Jiang P, Liang M, Dai X, Zhou H, Zhao F, Ji Y, Mo JQ, Qu J, Guan MX. Leber's hereditary optic neuropathy is associated with the T3866C mutation in mitochondrial ND1 gene in three Han Chinese Families. Invest Ophthalmol Vis Sci 2012; 53:4586-94. [PMID: 22577081 DOI: 10.1167/iovs.11-9109] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To investigate the pathophysiology of Leber's hereditary optic neuropathy (LHON). METHODS Seventy-one subjects from three Chinese families with LHON underwent clinical, genetic, molecular, and biochemical evaluations. Biochemical characterizations included the measurements of the rates of endogenous, substrate-dependent respirations, the adenosine triphosphate (ATP) production and generation of reactive oxygen species using lymphoblastoid cell lines derived from five affected matrilineal relatives of these families and three control subjects. RESULTS Ten of 41 matrilineal relatives exhibited variable severity and age at onset of optic neuropathy. The average age at onset of optic neuropathy in matrilineal relatives of the three families was 5, 11, and 24 years, respectively. Molecular analysis identified the ND1 T3866C (I187T) mutation and distinct sets of polymorphisms belonging to the Eastern Asian haplogroups D4a, M10a, and R, respectively. The I187T mutation is localized at the highly conserved isoleucine at a transmembrane domain of the ND1 polypeptide. The marked reductions in the rate of endogenous, malate/glutamate-promoted and succinate/glycerol-3-phosphate-promoted respiration were observed in mutant cell lines carrying the T3866C mutation. The deficient respiration is responsible for the reduced ATP synthesis and increased generation of reactive oxygen species. CONCLUSIONS Our data convincingly show that the ND1 T3866C mutation leads to LHON. This mutation may be insufficient to produce a clinical phenotype. Other modifier factors may contribute to the phenotypic manifestation of the T3866C mutation. The T3866C mutation should be added to the list of inherited factors for molecular diagnosis of LHON. Thus, our findings may provide new insights into the understanding of pathophysiology and valuable information on the management of LHON.
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Affiliation(s)
- Xiangtian Zhou
- School of Ophthalmology and Optometry, Wenzhou Medical College, Zhejiang, China
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25
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Liu Z, Song Y, Gu S, He X, Zhu X, Shen Y, Wu B, Wang W, Li S, Jiang P, Lu J, Huang W, Yan Q. Mitochondrial ND5 12338T>C variant is associated with maternally inherited hypertrophic cardiomyopathy in a Chinese pedigree. Gene 2012; 506:339-43. [PMID: 22759514 DOI: 10.1016/j.gene.2012.06.071] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2012] [Revised: 05/03/2012] [Accepted: 06/21/2012] [Indexed: 12/01/2022]
Abstract
Hypertrophic cardiomyopathy is a primary disorder characterized by asymmetric thickening of the septum and left ventricular wall, which affects 1 in 500 individuals in the general population. Mutations in mitochondrial DNA have been found to be one of the most important causes of hypertrophic cardiomyopathy. Here we report the clinical, genetic and molecular characterization of a Han Chinese family with a likely maternally transmitted hypertrophic cardiomyopathy. Four (2 men/2 women) of 5 matrilineal relatives in this 3-generation family exhibited the variable severity and age at onset of 44 to 79 years old. Sequence analysis of the entire mitochondrial DNA in this pedigree identified the known homoplasmic ND5 12338T>C variant. This mitochondrial DNA haplogroup belongs to the Eastern Asian F2a. The 12338T>C variant, highly evolutionarily conserved, resulted in the replacement of the translation initiating methionine with a threonine, shortening the ND5 polypeptide by 2 amino acids. The occurrence of ND5 12338T>C variant exclusively in maternal members of this Chinese family suggested that the 12338T>C variant is associated with maternally inherited hypertrophic cardiomyopathy. Our findings will provide theoretical basis for genetic counseling of maternally inherited hypertrophic cardiomyopathy.
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Affiliation(s)
- Zhong Liu
- The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, PR China
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Abstract
PURPOSE OF REVIEW Mitochondrial disease is a heterogeneous group of energy metabolism disorders that present across all ages with a wide range of ocular or multisystemic manifestations. This review focuses on recent progress made toward understanding the various ophthalmologic manifestations of primary mitochondrial diseases and discusses the implications of mitochondrial dysfunction, placing particular emphasis on recent investigations into the pathogenesis and emerging therapies for mitochondrial-based ophthalmologic disorders. RECENT FINDINGS Novel pathogenic mitochondrial DNA mutations continue to be detected in diverse ethnic populations for primary mitochondrial ophthalmologic disorders that commonly affect the optic nerve, retina, and extraocular muscles. Promising antioxidant and gene therapy approaches are being actively investigated to treat these ophthalmologic manifestations, as in Leber's hereditary optic neuropathy. Mitochondrial dysfunction is also increasingly implicated in common ophthalmologic disorders of aging, including diabetic retinopathy, age-related macular degeneration, and glaucoma. Several proteins recently recognized to play a role in the mitochondrial oxidative stress response within retinal cells, such as prohibitin and MMP2, may serve as novel biomarkers and therapeutic targets for common ophthalmologic disorders. Therapies that inhibit mitochondrial function and induce apoptosis within tumor cells, such as EDL-155 and curcumin, may offer novel therapeutic agents for ocular neoplasms such as retinoblastoma and uveal melanoma. SUMMARY Primary mitochondrial genetic disease manifestations can involve almost all aspects of the eye. Mitochondrial dysfunction is increasingly recognized as playing a causative role in the common ophthalmologic disorders in aging. This understanding has unleashed a range of emerging therapeutic approaches for mitochondrial-based ophthalmologic disorders directed at optimizing mitochondrial function.
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Bi R, Zhang AM, Yao YG. Leber's Hereditary Optic Neuropathy. Ophthalmology 2011; 118:1489-1489.e1. [DOI: 10.1016/j.ophtha.2011.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Accepted: 04/05/2011] [Indexed: 10/27/2022] Open
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