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Ding Y, Yu XJ, Guo QX, Leng JH. Functional analysis of the novel mitochondrial tRNA Trp and tRNA Ser(AGY) variants associated with type 2 diabetes mellitus. World J Diabetes 2024; 15:1753-1763. [DOI: 10.4239/wjd.v15.i8.1753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 05/09/2024] [Accepted: 06/18/2024] [Indexed: 07/25/2024] Open
Abstract
BACKGROUND Mutations in mitochondrial tRNA (mt-tRNA) genes that result in mitochondrial dysfunction play important roles in type 2 diabetes mellitus (T2DM). We pre-viously reported a large Chinese pedigree with maternally inherited T2DM that harbors novel mt-tRNATrpA5514G and tRNASer(AGY)C12237T variants, however, the effects of these mt-tRNA variants on T2DM progression are largely unknown.
AIM To assess the potential pathogenicity of T2DM-associated m.A5514G and m.C12237T variants at genetic, molecular, and biochemical levels.
METHODS Cytoplasmic hybrid (cybrid) cells carrying both m.A5514G and m.C12237T variants, and healthy control cells without these mitochondrial DNA (mtDNA) variants were generated using trans-mitochondrial technology. Mitochondrial features, including mt-tRNA steady-state level, levels of adenosine triphosphate (ATP), mitochondrial membrane potential (MMP), reactive oxygen species (ROS), mtDNA copy number, nicotinamide adenine dinucleotide (NAD+)/NADH ratio, enzymatic activities of respiratory chain complexes (RCCs), 8-hydroxy-deo-xyguanine (8-OhdG), malondialdehyde (MDA), and superoxide dismutase (SOD) were examined in cell lines with and without these mt-tRNA variants.
RESULTS Compared with control cells, the m.A5514G variant caused an approximately 35% reduction in the steady-state level of mt-tRNATrp (P < 0.0001); however, the m.C12237T variant did not affect the mt-tRNASer(AGY) steady-state level (P = 0.5849). Biochemical analysis revealed that cells with both m.A5514G and m.C12237T variants exhibited more severe mitochondrial dysfunctions and elevated oxidative stress than control cells: ATP, MMP, NAD+/NADH ratio, enzyme activities of RCCs and SOD levels were markedly decreased in mutant cells (P < 0.05 for all measures). By contrast, the levels of ROS, 8-OhdG and MDA were significantly increased (P < 0.05 for all measures), but mtDNA copy number was not affected by m.A5514G and m.C12237T variants (P = 0.5942).
CONCLUSION The m.A5514G variant impaired mt-tRNATrp metabolism, which subsequently caused mitochondrial dysfunction. The m.C12237T variant did not alter the steady-state level of mt-tRNASer(AGY), indicating that it may be a modifier of the m.A5514G variant. The m.A5514G variant may exacerbate the pathogenesis and progression of T2DM in this Chinese pedigree.
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Affiliation(s)
- Yu Ding
- Central Laboratory, Hangzhou First People’s Hospital, Hangzhou 310006, Zhejiang Province, China
| | - Xue-Jiao Yu
- Clinical Laboratory, Quzhou People’s Hospital, Quzhou 324000, Zhejiang Province, China
| | - Qin-Xian Guo
- Central Laboratory, Hangzhou First People’s Hospital, Hangzhou 310006, Zhejiang Province, China
| | - Jian-Hang Leng
- Central Laboratory, Hangzhou First People’s Hospital, Hangzhou 310006, Zhejiang Province, China
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Li X, Shang J, Li S, Wang Y. Identification of a Novel Mitochondrial tRNA Mutation in Chinese Family with Type 2 Diabetes Mellitus. Pharmgenomics Pers Med 2024; 17:149-161. [PMID: 38645701 PMCID: PMC11032666 DOI: 10.2147/pgpm.s438978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Accepted: 01/29/2024] [Indexed: 04/23/2024] Open
Abstract
Background Mutations in mitochondrial tRNA (mt-tRNA) could be the origin of some type 2 diabetes mellitus (T2DM) cases, but the mechanism remained largely unknown. Aim The aim of this study was to assess the impact of a novel mitochondrial tRNACys/tRNATyr A5826G mutation on the development and progression of T2DM. Methods A four-generation Han Chinese family with maternally inherited diabetes underwent clinical, genetic and biochemical analyses. The mitochondrial DNA (mtDNA) mutations of three matrilineal relatives were screened by PCR-Sanger sequencing. Furthermore, to see whether m.A5826G mutations affected mitochondrial functions, the cybrid cell lines were derived from three subjects with m.A5826G mutation and three controls without this mutation. ATP was evaluated by luminescent cell viability assay, mitochondrial membrane potential (MMP), and reactive oxygen species (ROS) were determined by flow cytometry. The student's two-tailed, unpaired t-test was used to assess the statistical significance between the control and mutant results. Results The age at onset of diabetes in this pedigree varied from 40 to 63 years, with an average of 54 years. Mutational analysis of mitochondrial genomes revealed the presence of a novel m.A5826G mutation. Interestingly, the m.A5826G mutation occurred at the conjunction between tRNACys and tRNATyr, a very conserved position that was critical for tRNAs processing and functions. Using trans-mitochondrial cybrid cells, we found that mutant cells carrying the m.A5826G showed approximately 36.5% and 22.4% reductions in ATP and MMP, respectively. By contrast, mitochondrial ROS levels increased approximately 33.3%, as compared with the wild type cells. Conclusion A novel m.A5826G mutation was identified in a pedigree with T2DM, and this mutation would lead to mitochondrial dysfunction. Thus, the genetic spectrum of mitochondrial diabetes was expanded by including m.A5826G mutation in tRNACys/tRNATyr, our study provided novel insight into the molecular pathogenesis, early diagnosis, prevention and clinical treatment for mitochondrial diabetes.
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Affiliation(s)
- Xing Li
- Department of Endocrinology, Ordos Center Hospital, Ordos, Inner Mongolian, 017010, People’s Republic of China
| | - Jinyao Shang
- Department of Endocrinology, Ordos Center Hospital, Ordos, Inner Mongolian, 017010, People’s Republic of China
| | - Shuang Li
- Department of Endocrinology, Ordos Center Hospital, Ordos, Inner Mongolian, 017010, People’s Republic of China
| | - Yue Wang
- Department of Endocrinology, Ordos Center Hospital, Ordos, Inner Mongolian, 017010, People’s Republic of China
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Zhang T, Su R, Xiang W, Wang W. Maternally inherited non-syndromic hearing loss is linked with a novel mitochondrial ND6 gene mutation. Ir J Med Sci 2024; 193:937-943. [PMID: 37561388 DOI: 10.1007/s11845-023-03484-6] [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: 06/02/2023] [Accepted: 07/26/2023] [Indexed: 08/11/2023]
Abstract
BACKGROUND Maternally inherited non-syndromic hearing loss is linked with mitochondrial DNA mutations. AIM This investigation demonstrates the features of a Chinese pedigree suffering from maternally inherited non-syndromic hearing loss. METHODS Biochemical characterizations included the measurements ofprotein synthesis levels, membrane potential, and the synthesis of reactive oxygen species (ROS) and adenosine triphosphate (ATP) using cybrid cell lines derived from an affected matrilineal subject and control subject. RESULTS Non-congenital early or late-onset/development hearing impairment has been observed in 4 of 9 in a family (matrilineal), with different degrees of hearing impairment, ranging from normal to severe. A pedigree's whole mitochondrial genome sequence analysis revealed the homoplasmic m.14502 T > C (I58V) mutation at ND6's isoleucine location-58, and specific mitocchondrial DNA polymorphisms set haplogroups M10 were highly conserved. In vitro models indicated that m.14502 T > C mutation-derived respiratory deficiency decreases ND6 protein synthesis, mitochondrial membrane potential, and ATP synthesis. These mitochondrial dysregulations enhance the generation of ROS in the mutant cells. Identifying nuclear modifiers is essential for elucidating hearing loss's pathogenesis and furnishing novel therapeutic interventions. CONCLUSIONS The m.14502 T > C mutation should be considered an inherited risk factor that can help diagnose. The data of this investigation help counsel families of individuals with hearing loss.
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Affiliation(s)
- Ting Zhang
- Department of Clinical Laboratory, The Affiliated Wenling Hospital, Wenzhou Medical University, Wenling, 317500, Zhejiang, China
| | - Renjie Su
- ENT Department, The First People's Hospital of Wenling, Taizhou University, Taizhou, China
- ENT Department, The Affiliated Wenling Hospital of Wenzhou Medical University, Taizhou, China
| | - Wen Xiang
- ENT Department, The First People's Hospital of Wenling, Taizhou University, Taizhou, China
- ENT Department, The Affiliated Wenling Hospital of Wenzhou Medical University, Taizhou, China
| | - Wenbin Wang
- ENT Department, The First People's Hospital of Wenling, Taizhou University, Taizhou, China.
- ENT Department, The Affiliated Wenling Hospital of Wenzhou Medical University, Taizhou, China.
- The First People's Hospital of Wenling, Taizhou University, 333 Chuanannan Road, Taizhou, 317500, China.
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Xiao Liang K. Interplay of mitochondria and diabetes: Unveiling novel therapeutic strategies. Mitochondrion 2024; 75:101850. [PMID: 38331015 DOI: 10.1016/j.mito.2024.101850] [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: 08/16/2023] [Revised: 12/26/2023] [Accepted: 02/01/2024] [Indexed: 02/10/2024]
Abstract
The interplay between mitochondrial function and diabetes has gained significant attention due to its crucial role in the pathogenesis and progression of the disease. Mitochondria, known as the cellular powerhouses, are essential for glucose metabolism. Dysfunction of these organelles has been implicated in the development of insulin resistance and beta-cell failure, both prominent features of diabetes. This comprehensive review explores the intricate mechanisms involved, including the generation of reactive oxygen species and the impact of mitochondrial DNA (mtDNA) mutations. Moreover, the review delves into emerging therapeutic strategies that specifically target mitochondria, such as mitochondria-targeted antioxidants, agents promoting mitochondrial biogenesis, and compounds modulating mitochondrial dynamics. The potential of these novel approaches is critically evaluated, taking into account their benefits and limitations, to provide a well-rounded perspective. Ultimately, this review emphasizes the importance of advancing our understanding of mitochondrial biology to revolutionize the treatment of diabetes.
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Wang C, Deng X, Li L, Li M. Maternally Inherited Essential Hypertension May Be Associated with the Mutations in Mitochondrial tRNA Glu Gene. Pharmgenomics Pers Med 2024; 17:13-26. [PMID: 38222291 PMCID: PMC10787565 DOI: 10.2147/pgpm.s436235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 12/21/2023] [Indexed: 01/16/2024] Open
Abstract
Background Mitochondrial DNA (mtDNA) mutations are associated with essential hypertension (EH), but the molecular mechanism remains largely unknown. Objective The aim of this study is to explore the association between mtDNA mutations and EH. Methods Two maternally inherited families with EH are underwent clinical, genetic and biochemical assessments. mtDNA mutations are screened by PCR-Sanger sequencing and phylogenetic, and bioinformatics analyses are performed to evaluate the pathogenicity of mtDNA mutations. We also generate cytoplasmic hybrid (cybrid) cell lines to analysis mitochondrial functions. Results Matrilineal relatives exhibit variable degree of clinical phenotypes. Molecular analysis reveals the presence of m.A14693G and m.A14696G mutations in two pedigrees. Notably, the m.A14693G mutation occurs at position 54 in the TψC loop of tRNAGlu, a position which is critical for post-transcriptionally modification of tRNAGlu. While the m.A14696G mutation creates a novel base-pairing (51C-64G). Bioinformatic analysis shows that these mutations alter tRNAGlu secondary structure. Additionally, patients with tRNAGlu mutations exhibit markedly decreased in mtDNA copy number, mitochondrial membrane potential (MMP) and ATP, whereas the levels of reactive oxygen species (ROS) increase significantly. Conclusion The m.A14696G and m.A14693G mutations lead to failure in tRNAGlu metabolism and cause mitochondrial dysfunction that is responsible for EH.
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Affiliation(s)
- Chun Wang
- Department of Integrated TCM & Western Medicine, Mengcheng County Second People’s Hospital, Anhui, 233500, People’s Republic of China
| | - Xin Deng
- Department of Integrated TCM & Western Medicine, Mengcheng County Second People’s Hospital, Anhui, 233500, People’s Republic of China
| | - Lei Li
- Department of Cardiology, Mengcheng County Second People’s Hospital, Anhui, 233500, People’s Republic of China
| | - Mei Li
- Department of Pharmacy, Mengcheng County Second People’s Hospital, Anhui, 233500, People’s Republic of China
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Popov LD. Mitochondria as intracellular signalling organelles. An update. Cell Signal 2023:110794. [PMID: 37422005 DOI: 10.1016/j.cellsig.2023.110794] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/23/2023] [Accepted: 07/02/2023] [Indexed: 07/10/2023]
Abstract
Traditionally, mitochondria are known as "the powerhouse of the cell," responsible for energy (ATP) generation (by the electron transport chain, oxidative phosphorylation, the tricarboxylic acid cycle, and fatty acid ß-oxidation), and for the regulation of several metabolic processes, including redox homeostasis, calcium signalling, and cellular apoptosis. The extensive studies conducted in the last decades portray mitochondria as multifaceted signalling organelles that ultimately command cells' survival or death. Based on current knowledge, we'll outline the mitochondrial signalling to other intracellular compartments in homeostasis and pathology-related mitochondrial stress conditions here. The following topics are discussed: (i) oxidative stress and mtROS signalling in mitohormesis, (ii) mitochondrial Ca2+ signalling; (iii) the anterograde (nucleus-to-mitochondria) and retrograde (mitochondria-to-nucleus) signal transduction, (iv) the mtDNA role in immunity and inflammation, (v) the induction of mitophagy- and apoptosis - signalling cascades, (vi) the mitochondrial dysfunctions (mitochondriopathies) in cardiovascular, neurodegenerative, and malignant diseases. The novel insights into molecular mechanisms of mitochondria-mediated signalling can explain mitochondria adaptation to metabolic and environmental stresses to achieve cell survival.
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Affiliation(s)
- Lucia-Doina Popov
- Institute of Cellular Biology and Pathology "Nicolae Simionescu" of the Romanian Academy, 8, B.P. Hasdeu Street, 050568 Bucharest, Romania.
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Rahmadanthi FR, Maksum IP. Transfer RNA Mutation Associated with Type 2 Diabetes Mellitus. BIOLOGY 2023; 12:871. [PMID: 37372155 DOI: 10.3390/biology12060871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/09/2023] [Accepted: 06/12/2023] [Indexed: 06/29/2023]
Abstract
Transfer RNA (tRNA) genes in the mitochondrial DNA genome play an important role in protein synthesis. The 22 tRNA genes carry the amino acid that corresponds to that codon but changes in the genetic code often occur such as gene mutations that impact the formation of adenosine triphosphate (ATP). Insulin secretion does not occur because the mitochondria cannot work optimally. tRNA mutation may also be caused by insulin resistance. In addition, the loss of tRNA modification can cause pancreatic β cell dysfunction. Therefore, both can be indirectly associated with diabetes mellitus because diabetes mellitus, especially type 2, is caused by insulin resistance and the body cannot produce insulin. In this review, we will discuss tRNA in detail, several diseases related to tRNA mutations, how tRNA mutations can lead to type 2 diabetes mellitus, and one example of a point mutation that occurs in tRNA.
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Affiliation(s)
- Fanny Rizki Rahmadanthi
- Departement of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Sumedang 45363, Indonesia
| | - Iman Permana Maksum
- Departement of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Sumedang 45363, Indonesia
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Ding Y, Zhang S, Guo Q, Leng J. Mitochondrial Diabetes Is Associated with the ND4 G11696A Mutation. Biomolecules 2023; 13:907. [PMID: 37371486 DOI: 10.3390/biom13060907] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/21/2023] [Accepted: 05/25/2023] [Indexed: 06/29/2023] Open
Abstract
Type 2 diabetes mellitus (T2DM) is a common endocrine disorder which remains a large challenge for clinicians. Previous studies have suggested that mitochondrial dysfunction plays an active role in T2DM progression, but a detailed mechanism is still elusive. In the current study, two Han Chinese families with maternally inherited T2DM were evaluated using clinical, genetic, molecular, and biochemical analyses. The mitochondrial genomes were PCR amplified and sequenced. Phylogenetic and bioinformatic analyses were used to assess the potential pathogenicity of mitochondrial DNA (mtDNA) mutations. Interestingly, the matrilineal relatives of these pedigrees exhibited variable severity of T2DM, in particular, the age at onset of T2DM varied from 26 to 65 years, with an average of 49 years. Sequence analysis revealed the presence of ND4 G11696A mutation, which resulted in the substitution of an isoleucine for valine at amino acid (AA) position 312. Indeed, this mutation was present in homoplasmy only in the maternal lineage, not in other members of these families, as well as 200 controls. Furthermore, the m.C5601T in the tRNAAla and novel m.T5813C in the tRNACys, showing high evolutional conservation, may contribute to the phenotypic expression of ND4 G11696A mutation. In addition, biochemical analysis revealed that cells with ND4 G11696A mutation exhibited higher levels of reactive oxygen species (ROS) productions than the controls. In contrast, the levels of mitochondrial membrane potential (MMP), ATP, mtDNA copy number (mtDNA-CN), Complex I activity, and NAD+/NADH ratio significantly decreased in cell lines carrying the m.G11696A and tRNA mutations, suggesting that these mutations affected the respiratory chain function and led to mitochondrial dysfunction that was involved in T2DM. Thus, our study broadened the clinical phenotypes of m.G11696A mutation.
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Affiliation(s)
- Yu Ding
- Central Laboratory, Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou 310006, China
| | - Shunrong Zhang
- Department of Geriatrics, Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou 310006, China
| | - Qinxian Guo
- Central Laboratory, Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou 310006, China
| | - Jianhang Leng
- Central Laboratory, Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou 310006, China
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