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Jacovetti C, Donnelly C, Menoud V, Suleiman M, Cosentino C, Sobel J, Wu K, Bouzakri K, Marchetti P, Guay C, Kayser B, Regazzi R. The mitochondrial tRNA-derived fragment, mt-tRF-Leu TAA, couples mitochondrial metabolism to insulin secretion. Mol Metab 2024; 84:101955. [PMID: 38704026 PMCID: PMC11112368 DOI: 10.1016/j.molmet.2024.101955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 04/29/2024] [Accepted: 04/29/2024] [Indexed: 05/06/2024] Open
Abstract
OBJECTIVE The contribution of the mitochondrial electron transfer system to insulin secretion involves more than just energy provision. We identified a small RNA fragment (mt-tRF-LeuTAA) derived from the cleavage of a mitochondrially-encoded tRNA that is conserved between mice and humans. The role of mitochondrially-encoded tRNA-derived fragments remains unknown. This study aimed to characterize the impact of mt-tRF-LeuTAA, on mitochondrial metabolism and pancreatic islet functions. METHODS We used antisense oligonucleotides to reduce mt-tRF-LeuTAA levels in primary rat and human islet cells, as well as in insulin-secreting cell lines. We performed a joint transcriptome and proteome analysis upon mt-tRF-LeuTAA inhibition. Additionally, we employed pull-down assays followed by mass spectrometry to identify direct interactors of the fragment. Finally, we characterized the impact of mt-tRF-LeuTAA silencing on the coupling between mitochondrial metabolism and insulin secretion using high-resolution respirometry and insulin secretion assays. RESULTS Our study unveils a modulation of mt-tRF-LeuTAA levels in pancreatic islets in different Type 2 diabetes models and in response to changes in nutritional status. The level of the fragment is finely tuned by the mechanistic target of rapamycin complex 1. Located within mitochondria, mt-tRF-LeuTAA interacts with core subunits and assembly factors of respiratory complexes of the electron transfer system. Silencing of mt-tRF-LeuTAA in islet cells limits the inner mitochondrial membrane potential and impairs mitochondrial oxidative phosphorylation, predominantly by affecting the Succinate (via Complex II)-linked electron transfer pathway. Lowering mt-tRF-LeuTAA impairs insulin secretion of rat and human pancreatic β-cells. CONCLUSIONS Our findings indicate that mt-tRF-LeuTAA interacts with electron transfer system complexes and is a pivotal regulator of mitochondrial oxidative phosphorylation and its coupling to insulin secretion.
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Affiliation(s)
- Cecile Jacovetti
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland.
| | - Chris Donnelly
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Véronique Menoud
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Mara Suleiman
- Department of Clinical and Experimental Medicine, Diabetes Unit, University of Pisa, Pisa, Italy
| | - Cristina Cosentino
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Jonathan Sobel
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Kejing Wu
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Karim Bouzakri
- UMR DIATHEC, EA 7294, Centre Européen d'Etude du Diabète, Université de Strasbourg, Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
| | - Piero Marchetti
- Department of Clinical and Experimental Medicine, Diabetes Unit, University of Pisa, Pisa, Italy
| | - Claudiane Guay
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Bengt Kayser
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Romano Regazzi
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland; Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
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Kabra UD, Jastroch M. Mitochondrial Dynamics and Insulin Secretion. Int J Mol Sci 2023; 24:13782. [PMID: 37762083 PMCID: PMC10530730 DOI: 10.3390/ijms241813782] [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: 08/05/2023] [Revised: 08/30/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023] Open
Abstract
Mitochondria are involved in the regulation of cellular energy metabolism, calcium homeostasis, and apoptosis. For mitochondrial quality control, dynamic processes, such as mitochondrial fission and fusion, are necessary to maintain shape and function. Disturbances of mitochondrial dynamics lead to dysfunctional mitochondria, which contribute to the development and progression of numerous diseases, including Type 2 Diabetes (T2D). Compelling evidence has been put forward that mitochondrial dynamics play a significant role in the metabolism-secretion coupling of pancreatic β cells. The disruption of mitochondrial dynamics is linked to defects in energy production and increased apoptosis, ultimately impairing insulin secretion and β cell death. This review provides an overview of molecular mechanisms controlling mitochondrial dynamics, their dysfunction in pancreatic β cells, and pharmaceutical agents targeting mitochondrial dynamic proteins, such as mitochondrial division inhibitor-1 (mdivi-1), dynasore, P110, and 15-oxospiramilactone (S3).
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Affiliation(s)
- Uma D. Kabra
- Department of Pharmaceutical Chemistry, Parul Institute of Pharmacy, Parul University, Vadodara 391760, India;
| | - Martin Jastroch
- The Arrhenius Laboratories F3, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
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Ryytty S, Hämäläinen RH. The Mitochondrial m.3243A>G Mutation on the Dish, Lessons from In Vitro Models. Int J Mol Sci 2023; 24:13478. [PMID: 37686280 PMCID: PMC10487608 DOI: 10.3390/ijms241713478] [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: 08/16/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023] Open
Abstract
The m.3243A>G mutation in the tRNA Leu(UUR) gene (MT-TL1) is one of the most common pathogenic point mutations in human mtDNA. Patient symptoms vary widely and the severity of the disease ranges from asymptomatic to lethal. The reason for the high heterogeneity of m.3243A>G-associated disease is still unknown, and the treatment options are limited, with only supportive interventions available. Furthermore, the heteroplasmic nature of the m.3243A>G mutation and lack of specific animal models of mtDNA mutations have challenged the study of m.3243A>G, and, besides patient data, only cell models have been available for studies. The most commonly used cell models are patient derived, such as fibroblasts and induced pluripotent stem cell (iPSC)-derived models, and cybrid models where the mutant DNA is transferred to an acceptor cell. Studies on cell models have revealed cell-type-specific effects of the m.3243A>G mutation and that the tolerance for this mutation varies between cell types and between patients. In this review, we summarize the literature on the effects of m.3243A>G in cell models.
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Affiliation(s)
| | - Riikka H. Hämäläinen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Neulaniementie 2, 70211 Kuopio, Finland;
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4
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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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Memon AA, Vats S, Sundquist J, Li Y, Sundquist K. Mitochondrial DNA Copy Number: Linking Diabetes and Cancer. Antioxid Redox Signal 2022; 37:1168-1190. [PMID: 36169625 DOI: 10.1089/ars.2022.0100] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Recent Advances: Various studies have suggested that mitochondrial DNA copy number (mtDNA-CN), a surrogate biomarker of mitochondrial dysfunction, is an easily quantifiable biomarker for chronic diseases, including diabetes and cancer. However, current knowledge is limited, and the results are controversial. This has been attributed mainly to methodology and study design. Critical Issues: The incidence of diabetes and cancer has increased significantly in recent years. Moreover, type 2 diabetes (T2D) has been shown to be a risk factor for cancer. mtDNA-CN has been associated with both T2D and cancer. However, it is not known whether mtDNA-CN plays any role in the association between T2D and cancer. Significance: In this review, we have discussed mtDNA-CN in diabetes and cancer, and reviewed the literature and methodology used in published studies so far. Based on the literature review, we have speculated how mtDNA-CN may act as a link between diabetes and cancer. Furthermore, we have provided some recommendations for reliable translation of mtDNA-CN as a biomarker. Future Directions: Further research is required to elucidate the role of mtDNA-CN in the association between T2D and cancer. If established, early lifestyle interventions, such as physical activity and diet control that improve mitochondrial function, may help preventing cancer in patients with T2D. Antioxid. Redox Signal. 37, 1168-1190.
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Affiliation(s)
- Ashfaque A Memon
- Center for Primary Health Care Research, Lund University/Region Skåne, Malmö, Sweden
| | - Sakshi Vats
- Center for Primary Health Care Research, Lund University/Region Skåne, Malmö, Sweden
| | - Jan Sundquist
- Center for Primary Health Care Research, Lund University/Region Skåne, Malmö, Sweden
| | - Yanni Li
- Center for Primary Health Care Research, Lund University/Region Skåne, Malmö, Sweden
| | - Kristina Sundquist
- Center for Primary Health Care Research, Lund University/Region Skåne, Malmö, Sweden
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Is Type 2 Diabetes a Primary Mitochondrial Disorder? Cells 2022; 11:cells11101617. [PMID: 35626654 PMCID: PMC9140179 DOI: 10.3390/cells11101617] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/27/2022] [Accepted: 04/20/2022] [Indexed: 02/06/2023] Open
Abstract
Diabetes mellitus is the most common endocrine disturbance in inherited mitochondrial diseases. It is essential to increase awareness of the correct diagnosis and treatment of diabetes in these patients and screen for the condition in family members, as diabetes might appear with distinctive clinical features, complications and at different ages of onset. The severity of mitochondrial-related diabetes is likely to manifest on a large scale of phenotypes depending on the location of the mutation and whether the number of affected mitochondria copies (heteroplasmy) reaches a critical threshold. Regarding diabetes treatment, the first-choice treatment for type 2 diabetes (T2D), metformin, is not recommended because of the risk of lactic acidosis. The preferred treatment for diabetes in patients with mitochondrial disorders is SGLT-2i and mitochondrial GLP-1-related substances. The tight relationship between mitochondrial dysfunction, reduced glucose-stimulated insulin secretion (GSIS), and diabetes development in human patients is acknowledged. However, despite the well-characterized role of mitochondria in GSIS, there is a relative lack of data in humans implicating mitochondrial dysfunction as a primary defect in T2D. Our recent studies have provided data supporting the significant role of the mitochondrial respiratory-chain enzyme, cytochrome c oxidase (COX), in regulating GSIS in a rodent model of T2D, the Cohen diabetic sensitive (CDs) rat. The nutritionally induced diabetic CDs rat demonstrates several features of mitochondrial diseases: markedly reduced COX activity in several tissues, increased reactive oxygen production, decreased ATP generation, and increased lactate dehydrogenase expression in islets. Moreover, our data demonstrate that reduced islet-COX activity precedes the onset of diabetes, suggesting that islet-COX deficiency is the primary defect causing diabetes in this model. This review examines the possibility of including T2D as a primary mitochondrial-related disease. Understanding the critical interdependence between diabetes and mitochondrial dysfunction, centering on the role of COX, may open novel avenues to diagnose and treat diabetes in patients with mitochondrial diseases and mitochondrial dysfunction in diabetic patients.
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Aharon-Hananel G, Romero-Afrima L, Saada A, Mantzur C, Raz I, Weksler-Zangen S. Cytochrome c Oxidase Activity as a Metabolic Regulator in Pancreatic Beta-Cells. Cells 2022; 11:cells11060929. [PMID: 35326380 PMCID: PMC8946064 DOI: 10.3390/cells11060929] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/01/2022] [Accepted: 03/03/2022] [Indexed: 02/06/2023] Open
Abstract
Pancreatic β-cells couple glucose-stimulated insulin secretion (GSIS) with oxidative phosphorylation via cytochrome c oxidase (COX), a mitochondrial respiratory-chain enzyme. The Cohen diabetic-sensitive (CDs) rats exhibit hyperglycemia when fed a diabetogenic diet but maintain normoglycemia on a regular diet. We have previously reported a decreased COX activity in CDs rats and explored its relevance for type 2 diabetes (T2D). In this study, we investigated the relation between COX activity in islets, peripheral-blood mononuclear cells (PBMCs), and GSIS during diabetes development in CDs rats fed a diabetogenic diet for 4, 11, 20, and 30 days and during reversion to normoglycemia in hyperglycemic CDs rats fed a reversion diet for 7, 11, and 20 days. An oral glucose-tolerance test was performed at different periods of the diets measuring blood glucose and insulin concentrations. COX activity was determined in islets and PBMCs isolated from rats at the different periods of the diets. We demonstrated a progressive reduction in COX activity in CDs-islets that correlated positively with the decreasing GSIS (R2 = 0.9691, p < 0.001) and inversely with the elevation in blood glucose levels (R2 = 0.8396, p < 0.001). Hyperglycemia was initiated when islet COX activity decreased below 46%. The reversion diet restored >46% of the islet COX activity and GSIS while re-establishing normoglycemia. Interestingly, COX activity in PBMCs correlated significantly with islet COX activity (R2 = 0.8944, p < 0.001). Our data support islet COX activity as a major metabolic regulator of β-cells function. The correlation between COX activity in PBMCs and islets may serve as a noninvasive biomarker to monitor β-cell dysfunction in diabetes.
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Affiliation(s)
- Genya Aharon-Hananel
- The Hadassah Diabetes Center, Hadassah Medical Center, Jerusalem 9112102, Israel; (G.A.-H.); (L.R.-A.); (C.M.); (I.R.)
- Division of Endocrinology, Diabetes and Metabolism, The Chaim Sheba Medical Center, Tel Hashomer, Ramat-Gan 5266202, Israel
- Sackler School of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
- The Department of Genetics, Hadassah Medical Center, Jerusalem 9112102, Israel;
| | - Leonor Romero-Afrima
- The Hadassah Diabetes Center, Hadassah Medical Center, Jerusalem 9112102, Israel; (G.A.-H.); (L.R.-A.); (C.M.); (I.R.)
- The Department of Genetics, Hadassah Medical Center, Jerusalem 9112102, Israel;
| | - Ann Saada
- The Department of Genetics, Hadassah Medical Center, Jerusalem 9112102, Israel;
- Faculty of Medicine Hebrew, University of Jerusalem, Jerusalem 9112102, Israel
| | - Carmit Mantzur
- The Hadassah Diabetes Center, Hadassah Medical Center, Jerusalem 9112102, Israel; (G.A.-H.); (L.R.-A.); (C.M.); (I.R.)
| | - Itamar Raz
- The Hadassah Diabetes Center, Hadassah Medical Center, Jerusalem 9112102, Israel; (G.A.-H.); (L.R.-A.); (C.M.); (I.R.)
- Faculty of Medicine Hebrew, University of Jerusalem, Jerusalem 9112102, Israel
| | - Sarah Weksler-Zangen
- The Hadassah Diabetes Center, Hadassah Medical Center, Jerusalem 9112102, Israel; (G.A.-H.); (L.R.-A.); (C.M.); (I.R.)
- Faculty of Medicine Hebrew, University of Jerusalem, Jerusalem 9112102, Israel
- The Liver Research Laboratory, Hadassah Medical Center, Jerusalem 9112102, Israel
- Correspondence: ; Tel.: +972-50-5172008
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8
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Rewiring cell signalling pathways in pathogenic mtDNA mutations. Trends Cell Biol 2021; 32:391-405. [PMID: 34836781 DOI: 10.1016/j.tcb.2021.10.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/19/2021] [Accepted: 10/22/2021] [Indexed: 12/24/2022]
Abstract
Mitochondria generate the energy to sustain cell viability and serve as a hub for cell signalling. Their own genome (mtDNA) encodes genes critical for oxidative phosphorylation. Mutations of mtDNA cause major disease and disability with a wide range of presentations and severity. We review here an emerging body of data suggesting that changes in cell metabolism and signalling pathways in response to the presence of mtDNA mutations play a key role in shaping disease presentation and progression. Understanding the impact of mtDNA mutations on cellular energy homeostasis and signalling pathways seems fundamental to identify novel therapeutic interventions with the potential to improve the prognosis for patients with primary mitochondrial disease.
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9
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Constitutive activation of the PI3K-Akt-mTORC1 pathway sustains the m.3243 A > G mtDNA mutation. Nat Commun 2021; 12:6409. [PMID: 34737295 PMCID: PMC8568893 DOI: 10.1038/s41467-021-26746-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 10/20/2021] [Indexed: 11/25/2022] Open
Abstract
Mutations of the mitochondrial genome (mtDNA) cause a range of profoundly debilitating clinical conditions for which treatment options are very limited. Most mtDNA diseases show heteroplasmy – tissues express both wild-type and mutant mtDNA. While the level of heteroplasmy broadly correlates with disease severity, the relationships between specific mtDNA mutations, heteroplasmy, disease phenotype and severity are poorly understood. We have carried out extensive bioenergetic, metabolomic and RNAseq studies on heteroplasmic patient-derived cells carrying the most prevalent disease related mtDNA mutation, the m.3243 A > G. These studies reveal that the mutation promotes changes in metabolites which are associated with the upregulation of the PI3K-Akt-mTORC1 axis in patient-derived cells and tissues. Remarkably, pharmacological inhibition of PI3K, Akt, or mTORC1 reduced mtDNA mutant load and partially rescued cellular bioenergetic function. The PI3K-Akt-mTORC1 axis thus represents a potential therapeutic target that may benefit people suffering from the consequences of the m.3243 A > G mutation. Heteroplasmic mtDNA mutations cause disease in humans. Here, Chung et al find the PI3K-Akt-mTORC1 pathway constitutively activated in cells with the heteroplasmic m.3243 A > G mutation, and inhibition of the pathway cell autonomously reduces mutant mtDNA load and rescues mitochondrial bioenergetics.
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Sanchez Caballero L, Gorgogietas V, Arroyo MN, Igoillo-Esteve M. Molecular mechanisms of β-cell dysfunction and death in monogenic forms of diabetes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 359:139-256. [PMID: 33832649 DOI: 10.1016/bs.ircmb.2021.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Monogenetic forms of diabetes represent 1%-5% of all diabetes cases and are caused by mutations in a single gene. These mutations, that affect genes involved in pancreatic β-cell development, function and survival, or insulin regulation, may be dominant or recessive, inherited or de novo. Most patients with monogenic diabetes are very commonly misdiagnosed as having type 1 or type 2 diabetes. The severity of their symptoms depends on the nature of the mutation, the function of the affected gene and, in some cases, the influence of additional genetic or environmental factors that modulate severity and penetrance. In some patients, diabetes is accompanied by other syndromic features such as deafness, blindness, microcephaly, liver and intestinal defects, among others. The age of diabetes onset may also vary from neonatal until early adulthood manifestations. Since the different mutations result in diverse clinical presentations, patients usually need different treatments that range from just diet and exercise, to the requirement of exogenous insulin or other hypoglycemic drugs, e.g., sulfonylureas or glucagon-like peptide 1 analogs to control their glycemia. As a consequence, awareness and correct diagnosis are crucial for the proper management and treatment of monogenic diabetes patients. In this chapter, we describe mutations causing different monogenic forms of diabetes associated with inadequate pancreas development or impaired β-cell function and survival, and discuss the molecular mechanisms involved in β-cell demise.
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Affiliation(s)
- Laura Sanchez Caballero
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/
| | - Vyron Gorgogietas
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/
| | - Maria Nicol Arroyo
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/
| | - Mariana Igoillo-Esteve
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/.
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Inthu DM, Paul DSFD, Palanippan DN, Dr. Kumarasamy. Mitochondrial DNA Mutations and ND1 Gene Copy Number in Patients with Polycystic Ovary Syndrome (PCOS). CYTOL GENET+ 2020. [DOI: 10.3103/s0095452720030056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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Dolinko AH, Chwa M, Atilano SR, Kenney MC. African and Asian Mitochondrial DNA Haplogroups Confer Resistance Against Diabetic Stresses on Retinal Pigment Epithelial Cybrid Cells In Vitro. Mol Neurobiol 2020; 57:1636-1655. [PMID: 31811564 PMCID: PMC7123578 DOI: 10.1007/s12035-019-01834-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 11/12/2019] [Indexed: 01/09/2023]
Abstract
Diabetic retinopathy (DR) is the most common cause of blindness for individuals under the age of 65. This loss of vision can be due to ischemia, neovascularization, and/or diabetic macular edema, which are caused by breakdown of the blood-retina barrier at the level of the retinal pigment epithelium (RPE) and inner retinal vasculature. The prevalence of diabetes and its complications differ between Caucasian-Americans and certain minority populations, such as African-Americans and Asian-Americans. Individuals can be classified by their mitochondrial haplogroups, which are collections of single nucleotide polymorphisms (SNPs) in mitochondrial DNA (mtDNA) representing ancient geographic origins of populations. In this study, we compared the responses of diabetic human RPE cybrids, cell lines containing identical nuclei but mitochondria from either European (maternal European) or maternal African or Asian individuals, to hypoxia and high glucose levels. The African and Asian diabetic ([Afr+Asi]/DM) cybrids showed (1) resistance to both hyperglycemic and hypoxic stresses; (2) downregulation of pro-apoptotic indicator BAX; (3) upregulation of DNA methylation genes, such as DNMT3A and DNMT3B; and (4) resistance to DNA demethylation by the methylation inhibitor 5-Aza-2'-deoxycytidine (5-Aza-dC) compared to European diabetic (Euro/DM) cybrids. Our findings suggest that mitochondria from African and Asian diabetic subjects possess a "metabolic memory" that confers resistance against hyperglycemia, hypoxia, and demethylation, and that this "metabolic memory" can be transferred into the RPE cybrid cell lines in vitro.
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Affiliation(s)
- Andrew H Dolinko
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA, 92697, USA
- Department of Ophthalmology Research, Gavin Herbert Eye Institute, University of California Irvine, Hewitt Hall, Room 2028, 843 Health Science Road, Irvine, CA, 92697, USA
| | - Marilyn Chwa
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA, 92697, USA
| | - Shari R Atilano
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA, 92697, USA
| | - M Cristina Kenney
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA, 92697, USA.
- Department of Ophthalmology Research, Gavin Herbert Eye Institute, University of California Irvine, Hewitt Hall, Room 2028, 843 Health Science Road, Irvine, CA, 92697, USA.
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Ježek P, Dlasková A. Dynamic of mitochondrial network, cristae, and mitochondrial nucleoids in pancreatic β-cells. Mitochondrion 2019; 49:245-258. [DOI: 10.1016/j.mito.2019.06.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 06/21/2019] [Accepted: 06/24/2019] [Indexed: 12/17/2022]
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Saeed NAAAH, Hamzah IH, Al-Gharrawi SAR. Polycystic ovary syndrome dependency on mtDNA mutation; copy Number and its association with insulin resistance. BMC Res Notes 2019; 12:455. [PMID: 31340838 PMCID: PMC6657173 DOI: 10.1186/s13104-019-4453-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 07/09/2019] [Indexed: 12/26/2022] Open
Abstract
Objective Study analyzes mutation in mtDNA (Mitochondrial DNA) among diabetic women with PCOS in non-diabetic diabetic women and compared with the healthy control. Women with known case of hyperandrogenism, ovulatory dysfunction and/or polycystic ovaries were selected and anthropometric and demographic variables were collected during their clinical visit. Biochemical estimation of glucose, FSH, LH, estradiol (E2), and insulin levels were analyzed. Mutational analysis of mt-tRNA genes of each individual was compared with the updated consensus Cambridge sequence. The mtDNA content was determined in triplicate using SYBR green PCR mastermix. Results The clinical and biochemical characteristics of participants showed no statistical difference in age and/or FSH, PRL, E2, PRGE or fasting glucose value between patients of different groups. Women with PCOS-D had significantly higher LH, LH/FSH, TT and fasting insulin levels and HOMA-IR with respect to the control group. Ten different type of mutation were seen in POCS group. Most of these mutations were confined to evolutionarily conserved region. The mtDNA copy numbers were considerably lower PCOS group irrespective of diabetic status. To conclude, the current study inferred that the mutations occur in the mitochondrial genome, mt-tRNA in specific, are the important causal factor in PCOS.
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Affiliation(s)
- Noor AlHuda Ali A H Saeed
- Branch of Zoology, Biology Department, College of Science, Mustansiriyah University, POX 10422, Baghdad, Iraq
| | - Israa Hussein Hamzah
- Branch of Zoology, Biology Department, College of Science, Mustansiriyah University, POX 10422, Baghdad, Iraq. .,Dept. of Basic Science, College of Dentistry, Mustansiriyah University, POX 10422, Baghdad, Iraq.
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Geng X, Zhang Y, Yan J, Chu C, Gao F, Jiang Z, Zhang X, Chen Y, Wei X, Feng Y, Lu H, Wang C, Zeng F, Jia W. Mitochondrial DNA mutation m.3243A>G is associated with altered mitochondrial function in peripheral blood mononuclear cells, with heteroplasmy levels and with clinical phenotypes. Diabet Med 2019; 36:776-783. [PMID: 30536471 DOI: 10.1111/dme.13874] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/29/2018] [Indexed: 12/18/2022]
Abstract
AIMS To investigate the associations among heteroplasmy levels (i.e. the proportions of mutant and wild-type mitochondrial DNA in the same cell), mitochondrial function and clinical severity of the m.3243A>G mutation. METHODS A total of 17 participants carrying the m.3243A>G mutation and 17 sex- and age-matched healthy controls were included in this study. Heteroplasmy levels of the m.3243A>G mutation in leukocytes, saliva and urine sediment were determined by pyrosequencing. The clinical evaluation included endocrinological, audiological and ophthalmological examinations. Mitochondrial function was determined in peripheral blood mononuclear cells isolated from participants. RESULTS Heteroplasmy levels in urine sediment were higher than those in leukocytes and saliva. Reduced levels of adenosine triphosphate and mitochondrial membrane potential, and increased reactive oxygen species production were observed in mutant peripheral blood mononuclear cells (all P < 0.05). Linear regression analysis indicated that higher heteroplasmy levels in peripheral blood leukocytes were associated with increased levels of glycated albumin and HbA1c , and decreased total hip bone mineral density T-score after adjustment for age and sex (all P < 0.05). Furthermore, mitochondrial membrane potential was independently associated with bone mineral density T-score at the femoral neck (P < 0.05). CONCLUSIONS Heteroplasmy levels in peripheral blood leukocytes and mitochondrial membrane potential in peripheral blood mononuclear cells were closely associated with clinical manifestations and were valuable for evaluation of the clinical severity of the m.3243A>G mutation.
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Affiliation(s)
- X Geng
- Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Key Laboratory of Diabetes, Shanghai, China
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
- Metabolic Diseases Biobank, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Y Zhang
- Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Key Laboratory of Diabetes, Shanghai, China
- Metabolic Diseases Biobank, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
- Centre for Translational Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - J Yan
- Shanghai Institute of Medical Genetics, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
- Key Laboratory of Embryo Molecular Biology, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
- Ministry of Health of China and Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - C Chu
- Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Key Laboratory of Diabetes, Shanghai, China
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
- Metabolic Diseases Biobank, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - F Gao
- Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Key Laboratory of Diabetes, Shanghai, China
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
- Metabolic Diseases Biobank, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Z Jiang
- Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Key Laboratory of Diabetes, Shanghai, China
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
- Metabolic Diseases Biobank, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - X Zhang
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Y Chen
- Department of Ophthalmology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - X Wei
- Department of Diagnostic Radiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Y Feng
- Department of Otolaryngology Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - H Lu
- Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Key Laboratory of Diabetes, Shanghai, China
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
- Metabolic Diseases Biobank, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - C Wang
- Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Key Laboratory of Diabetes, Shanghai, China
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
- Metabolic Diseases Biobank, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - F Zeng
- Shanghai Institute of Medical Genetics, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
- Key Laboratory of Embryo Molecular Biology, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
- Ministry of Health of China and Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - W Jia
- Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Key Laboratory of Diabetes, Shanghai, China
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
- Metabolic Diseases Biobank, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
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16
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Mitochondrial Transfer of Wharton's Jelly Mesenchymal Stem Cells Eliminates Mutation Burden and Rescues Mitochondrial Bioenergetics in Rotenone-Stressed MELAS Fibroblasts. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:9537504. [PMID: 31249652 PMCID: PMC6556302 DOI: 10.1155/2019/9537504] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 04/03/2019] [Indexed: 12/28/2022]
Abstract
Wharton's jelly mesenchymal stem cells (WJMSCs) transfer healthy mitochondria to cells harboring a mitochondrial DNA (mtDNA) defect. Mitochondrial myopathy, encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is one of the major subgroups of mitochondrial diseases, caused by the mt.3243A>G point mutation in the mitochondrial tRNALeu(UUR) gene. The specific aim of the study is to investigate whether WJMSCs exert therapeutic effect for mitochondrial dysfunction in cells of MELAS patient through donating healthy mitochondria. We herein demonstrate that WJMSCs transfer healthy mitochondria into rotenone-stressed fibroblasts of a MELAS patient, thereby eliminating mutation burden and rescuing mitochondrial functions. In the coculture system in vitro study, WJMSCs transferred healthy mitochondria to rotenone-stressed MELAS fibroblasts. By inhibiting actin polymerization to block tunneling nanotubes (TNTs), the WJMSC-conducted mitochondrial transfer was abrogated. After mitochondrial transfer, the mt.3243A>G mutation burden of MELAS fibroblasts was reduced to an undetectable level, with long-term retention. Sequencing results confirmed that the transferred mitochondria were donated from WJMSCs. Furthermore, mitochondrial transfer of WJMSCs to MELAS fibroblasts improves mitochondrial functions and cellular performance, including protein translation of respiratory complexes, ROS overexpression, mitochondrial membrane potential, mitochondrial morphology and bioenergetics, cell proliferation, mitochondrion-dependent viability, and apoptotic resistance. This study demonstrates that WJMSCs exert bioenergetic therapeutic effects through mitochondrial transfer. This finding paves the way for the development of innovative treatments for MELAS and other mitochondrial diseases.
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17
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Mukaneza Y, Cohen A, Rivard MÈ, Tardif J, Deschênes S, Ruiz M, Laprise C, Des Rosiers C, Coderre L. mTORC1 is required for expression of LRPPRC and cytochrome- c oxidase but not HIF-1α in Leigh syndrome French Canadian type patient fibroblasts. Am J Physiol Cell Physiol 2019; 317:C58-C67. [PMID: 30995105 DOI: 10.1152/ajpcell.00160.2017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Leigh syndrome French Canadian type (LSFC) is a mitochondrial disease caused by mutations in the leucine-rich pentatricopeptide repeat-containing (LRPPRC) gene leading to a reduction of cytochrome-c oxidase (COX) expression reaching 50% in skin fibroblasts. We have shown that under basal conditions, LSFC and control cells display similar ATP levels. We hypothesized that this occurs through upregulation of mechanistic target of rapamycin (mTOR)-mediated metabolic reprogramming. Our results showed that compared with controls, LSFC cells exhibited an upregulation of the mTOR complex 1 (mTORC1)/p70 ribosomal S6 kinase pathway and higher levels of hypoxia-inducible factor 1α (HIF-1α) and its downstream target pyruvate dehydrogenase kinase 1 (PDHK1), a regulator of mitochondrial pyruvate dehydrogenase 1 (PDH1). Consistent with these signaling alterations, LSFC cells displayed a 40-61% increase in [U-13C6]glucose contribution to pyruvate, lactate, and alanine formation, as well as higher levels of the phosphorylated and inactive form of PDH1-α. Interestingly, inhibition of mTOR with rapamycin did not alter HIF-1α or PDHK1 protein levels in LSFC fibroblasts. However, this treatment increased PDH1-α phosphorylation in control and LSFC cells and reduced ATP levels in control cells. Rapamycin also decreased LRPPRC expression by 41 and 11% in LSFC and control cells, respectively, and selectively reduced COX subunit IV expression in LSFC fibroblasts. Taken together, our data demonstrate the importance of mTORC1, independent of the HIF-1α/PDHK1 axis, in maintaining LRPPRC and COX expression in LSFC cells.
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Affiliation(s)
- Yvette Mukaneza
- Department of Nutrition, Université de Montréal , Montreal, Quebec , Canada.,Research Centre, Montreal Heart Institute , Montreal, Quebec , Canada
| | - Aaron Cohen
- Research Centre, Montreal Heart Institute , Montreal, Quebec , Canada
| | - Marie-Ève Rivard
- Research Centre, Montreal Heart Institute , Montreal, Quebec , Canada
| | - Jessica Tardif
- Département des Sciences Fondamentales, Université du Québec à Chicoutimi, Chicoutimi, Quebec , Canada
| | - Sonia Deschênes
- Research Centre, Montreal Heart Institute , Montreal, Quebec , Canada
| | - Matthieu Ruiz
- Department of Medicine, Université de Montréal , Montreal, Quebec , Canada.,Research Centre, Montreal Heart Institute , Montreal, Quebec , Canada
| | | | - Catherine Laprise
- Département des Sciences Fondamentales, Université du Québec à Chicoutimi, Chicoutimi, Quebec , Canada
| | - Christine Des Rosiers
- Department of Nutrition, Université de Montréal , Montreal, Quebec , Canada.,Research Centre, Montreal Heart Institute , Montreal, Quebec , Canada
| | - Lise Coderre
- Department of Medicine, Université de Montréal , Montreal, Quebec , Canada.,Research Centre, Montreal Heart Institute , Montreal, Quebec , Canada
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18
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McMillan RP, Stewart S, Budnick JA, Caswell CC, Hulver MW, Mukherjee K, Srivastava S. Quantitative Variation in m.3243A > G Mutation Produce Discrete Changes in Energy Metabolism. Sci Rep 2019; 9:5752. [PMID: 30962477 PMCID: PMC6453956 DOI: 10.1038/s41598-019-42262-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 02/18/2019] [Indexed: 12/16/2022] Open
Abstract
Mitochondrial DNA (mtDNA) 3243A > G tRNALeu(UUR) heteroplasmic mutation (m.3243A > G) exhibits clinically heterogeneous phenotypes. While the high mtDNA heteroplasmy exceeding a critical threshold causes mitochondrial encephalomyopathy, lactic acidosis with stroke-like episodes (MELAS) syndrome, the low mtDNA heteroplasmy causes maternally inherited diabetes with or without deafness (MIDD) syndrome. How quantitative differences in mtDNA heteroplasmy produces distinct pathological states has remained elusive. Here we show that despite striking similarities in the energy metabolic gene expression signature, the mitochondrial bioenergetics, biogenesis and fuel catabolic functions are distinct in cells harboring low or high levels of the m.3243 A > G mutation compared to wild type cells. We further demonstrate that the low heteroplasmic mutant cells exhibit a coordinate induction of transcriptional regulators of the mitochondrial biogenesis, glucose and fatty acid metabolism pathways that lack in near homoplasmic mutant cells compared to wild type cells. Altogether, these results shed new biological insights on the potential mechanisms by which low mtDNA heteroplasmy may progressively cause diabetes mellitus.
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Affiliation(s)
- Ryan P McMillan
- Department of Human Nutrition, Foods and Exercise, Virginia Tech, Blacksburg, VA, 24061, USA.,Metabolic Phenotyping Core at Virginia Tech, Blacksburg, VA, 24061, USA
| | - Sidney Stewart
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, 24016, USA.,Edward Via College of Osteopathic Medicine, Auburn, AL, 36832, USA
| | - James A Budnick
- Department of Biomedical Sciences and Pathobiology, Center for One Health Research, VA-MD College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, 24060, USA
| | - Clayton C Caswell
- Department of Biomedical Sciences and Pathobiology, Center for One Health Research, VA-MD College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, 24060, USA
| | - Matthew W Hulver
- Department of Human Nutrition, Foods and Exercise, Virginia Tech, Blacksburg, VA, 24061, USA.,Metabolic Phenotyping Core at Virginia Tech, Blacksburg, VA, 24061, USA
| | - Konark Mukherjee
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, 24016, USA
| | - Sarika Srivastava
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, 24016, USA.
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19
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Oxidative Insults and Mitochondrial DNA Mutation Promote Enhanced Autophagy and Mitophagy Compromising Cell Viability in Pluripotent Cell Model of Mitochondrial Disease. Cells 2019; 8:cells8010065. [PMID: 30658448 PMCID: PMC6356288 DOI: 10.3390/cells8010065] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 01/11/2019] [Accepted: 01/15/2019] [Indexed: 12/12/2022] Open
Abstract
Dysfunction of mitochondria causes defects in oxidative phosphorylation system (OXPHOS) and increased production of reactive oxygen species (ROS) triggering the activation of the cell death pathway that underlies the pathogenesis of aging and various diseases. The process of autophagy to degrade damaged cytoplasmic components as well as dysfunctional mitochondria is essential for ensuring cell survival. We analyzed the role of autophagy inpatient-specific induced pluripotent stem (iPS) cells generated from fibroblasts of patients with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) with well-characterized mitochondrial DNA mutations and distinct OXPHOS defects. MELAS iPS cells recapitulated the pathogenesis of MELAS syndrome, and showed an increase of autophagy in comparison with its isogenic normal counterpart, whereas mitophagy is very scarce at the basal condition. Our results indicated that the existence of pathogenic mtDNA alone in mitochondrial disease was not sufficient to elicit the degradation of dysfunctional mitochondria. Nonetheless, oxidative insults induced bulk macroautophagy with the accumulation of autophagosomes and autolysosomes upon marked elevation of ROS, overload of intracellular calcium, and robust depolarization of mitochondrial membrane potential, while mitochondria respiratory function was impaired and widespread mitophagy compromised cell viability. Collectively, our studies provide insights into the dysfunction of autophagy and activation of mitophagy contributing to the pathological mechanism of mitochondrial disease.
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20
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Cruz MM, Lopes AB, Crisma AR, de Sá RCC, Kuwabara WMT, Curi R, de Andrade PBM, Alonso-Vale MIC. Palmitoleic acid (16:1n7) increases oxygen consumption, fatty acid oxidation and ATP content in white adipocytes. Lipids Health Dis 2018; 17:55. [PMID: 29554895 PMCID: PMC5859716 DOI: 10.1186/s12944-018-0710-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 03/13/2018] [Indexed: 12/27/2022] Open
Abstract
Background We have recently demonstrated that palmitoleic acid (16:1n7) increases lipolysis, glucose uptake and glucose utilization for energy production in white adipose cells. In the present study, we tested the hypothesis that palmitoleic acid modulates bioenergetic activity in white adipocytes. Methods For this, 3 T3-L1 pre-adipocytes were differentiated into mature adipocytes in the presence (or absence) of palmitic (16:0) or palmitoleic (16:1n7) acid at 100 or 200 μM. The following parameters were evaluated: lipolysis, lipogenesis, fatty acid (FA) oxidation, ATP content, oxygen consumption, mitochondrial mass, citrate synthase activity and protein content of mitochondrial oxidative phosphorylation (OXPHOS) complexes. Results Treatment with 16:1n7 during 9 days raised basal and isoproterenol-stimulated lipolysis, FA incorporation into triacylglycerol (TAG), FA oxidation, oxygen consumption, protein expression of subunits representing OXPHOS complex II, III, and V and intracellular ATP content. These effects were not observed in adipocytes treated with 16:0. Conclusions Palmitoleic acid, by concerted action on lipolysis, FA esterification, mitochondrial FA oxidation, oxygen consumption and ATP content, does enhance white adipocyte energy expenditure and may act as local hormone.
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Affiliation(s)
- Maysa M Cruz
- Department of Biological Sciences, Institute of Environmental Sciences, Chemical and Pharmaceutical, Federal University of São Paulo, 210, Sao Nicolau St, Diadema, 09913-030, Brazil
| | - Andressa B Lopes
- Department of Nursing , Health Sciences Center, Federal University of Espírito Santo, Vitória, Brazil
| | - Amanda R Crisma
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Roberta C C de Sá
- Department of Biological Sciences, Institute of Environmental Sciences, Chemical and Pharmaceutical, Federal University of São Paulo, 210, Sao Nicolau St, Diadema, 09913-030, Brazil
| | - Wilson M T Kuwabara
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Rui Curi
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.,Interdisciplinary Postgraduate Program in Health Sciences, Institute of Physical Activity Sciences and Sports, Cruzeiro do Sul University, São Paulo, Brazil
| | - Paula B M de Andrade
- Interdisciplinary Postgraduate Program in Health Sciences, Institute of Physical Activity Sciences and Sports, Cruzeiro do Sul University, São Paulo, Brazil
| | - Maria I C Alonso-Vale
- Department of Biological Sciences, Institute of Environmental Sciences, Chemical and Pharmaceutical, Federal University of São Paulo, 210, Sao Nicolau St, Diadema, 09913-030, Brazil.
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21
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Fex M, Nicholas LM, Vishnu N, Medina A, Sharoyko VV, Nicholls DG, Spégel P, Mulder H. The pathogenetic role of β-cell mitochondria in type 2 diabetes. J Endocrinol 2018; 236:R145-R159. [PMID: 29431147 DOI: 10.1530/joe-17-0367] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 01/15/2018] [Indexed: 12/17/2022]
Abstract
Mitochondrial metabolism is a major determinant of insulin secretion from pancreatic β-cells. Type 2 diabetes evolves when β-cells fail to release appropriate amounts of insulin in response to glucose. This results in hyperglycemia and metabolic dysregulation. Evidence has recently been mounting that mitochondrial dysfunction plays an important role in these processes. Monogenic dysfunction of mitochondria is a rare condition but causes a type 2 diabetes-like syndrome owing to β-cell failure. Here, we describe novel advances in research on mitochondrial dysfunction in the β-cell in type 2 diabetes, with a focus on human studies. Relevant studies in animal and cell models of the disease are described. Transcriptional and translational regulation in mitochondria are particularly emphasized. The role of metabolic enzymes and pathways and their impact on β-cell function in type 2 diabetes pathophysiology are discussed. The role of genetic variation in mitochondrial function leading to type 2 diabetes is highlighted. We argue that alterations in mitochondria may be a culprit in the pathogenetic processes culminating in type 2 diabetes.
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Affiliation(s)
- Malin Fex
- Department of Clinical Sciences in MalmöUnit of Molecular Metabolism, Lund University Diabetes Centre, Clinical Research Center, Malmö University Hospital, Lund University, Malmö, Sweden
| | - Lisa M Nicholas
- Department of Clinical Sciences in MalmöUnit of Molecular Metabolism, Lund University Diabetes Centre, Clinical Research Center, Malmö University Hospital, Lund University, Malmö, Sweden
| | - Neelanjan Vishnu
- Department of Clinical Sciences in MalmöUnit of Molecular Metabolism, Lund University Diabetes Centre, Clinical Research Center, Malmö University Hospital, Lund University, Malmö, Sweden
| | - Anya Medina
- Department of Clinical Sciences in MalmöUnit of Molecular Metabolism, Lund University Diabetes Centre, Clinical Research Center, Malmö University Hospital, Lund University, Malmö, Sweden
| | - Vladimir V Sharoyko
- Department of Clinical Sciences in MalmöUnit of Molecular Metabolism, Lund University Diabetes Centre, Clinical Research Center, Malmö University Hospital, Lund University, Malmö, Sweden
| | - David G Nicholls
- Department of Clinical Sciences in MalmöUnit of Molecular Metabolism, Lund University Diabetes Centre, Clinical Research Center, Malmö University Hospital, Lund University, Malmö, Sweden
| | - Peter Spégel
- Department of Clinical Sciences in MalmöUnit of Molecular Metabolism, Lund University Diabetes Centre, Clinical Research Center, Malmö University Hospital, Lund University, Malmö, Sweden
- Department of ChemistryCenter for Analysis and Synthesis, Lund University, Sweden
| | - Hindrik Mulder
- Department of Clinical Sciences in MalmöUnit of Molecular Metabolism, Lund University Diabetes Centre, Clinical Research Center, Malmö University Hospital, Lund University, Malmö, Sweden
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22
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The mycotoxin phomoxanthone A disturbs the form and function of the inner mitochondrial membrane. Cell Death Dis 2018; 9:286. [PMID: 29459714 PMCID: PMC5833434 DOI: 10.1038/s41419-018-0312-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 01/04/2018] [Indexed: 12/15/2022]
Abstract
Mitochondria are cellular organelles with crucial functions in the generation and distribution of ATP, the buffering of cytosolic Ca2+ and the initiation of apoptosis. Compounds that interfere with these functions are termed mitochondrial toxins, many of which are derived from microbes, such as antimycin A, oligomycin A, and ionomycin. Here, we identify the mycotoxin phomoxanthone A (PXA), derived from the endophytic fungus Phomopsis longicolla, as a mitochondrial toxin. We show that PXA elicits a strong release of Ca2+ from the mitochondria but not from the ER. In addition, PXA depolarises the mitochondria similarly to protonophoric uncouplers such as CCCP, yet unlike these, it does not increase but rather inhibits cellular respiration and electron transport chain activity. The respiration-dependent mitochondrial network structure rapidly collapses into fragments upon PXA treatment. Surprisingly, this fragmentation is independent from the canonical mitochondrial fission and fusion mediators DRP1 and OPA1, and exclusively affects the inner mitochondrial membrane, leading to cristae disruption, release of pro-apoptotic proteins, and apoptosis. Taken together, our results suggest that PXA is a mitochondrial toxin with a novel mode of action that might prove a useful tool for the study of mitochondrial ion homoeostasis and membrane dynamics.
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23
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Alexandar SP, Dhinakaran I, Ravi V, Parthasarathy N, Ganesan S, Bhaskaran M, Arun Kumar GP. Meta-Analysis of Association of Mitochondrial DNA Mutations with Type 2 Diabetes and Gestational Diabetes Mellitus. INT J HUM GENET 2018. [DOI: 10.1080/09723757.2018.1430110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Soundarya Priya Alexandar
- Human Genomics Laboratory, School of Chemical & Biotechnology, SASTRA University Thanjavur, Thanjavur 613 401, Tamil Nadu, India
| | - Indhumathi Dhinakaran
- Human Genomics Laboratory, School of Chemical & Biotechnology, SASTRA University Thanjavur, Thanjavur 613 401, Tamil Nadu, India
| | - Vidhya Ravi
- K.A.P. Viswanatham Govt. Medical College, Trichy, 620 001, Tamil Nadu, India
| | - Nandhini Parthasarathy
- Human Genomics Laboratory, School of Chemical & Biotechnology, SASTRA University Thanjavur, Thanjavur 613 401, Tamil Nadu, India
| | - Somasundari Ganesan
- Human Genomics Laboratory, School of Chemical & Biotechnology, SASTRA University Thanjavur, Thanjavur 613 401, Tamil Nadu, India
| | - Muthumeenakshi Bhaskaran
- Human Genomics Laboratory, School of Chemical & Biotechnology, SASTRA University Thanjavur, Thanjavur 613 401, Tamil Nadu, India
| | - Ganesh Prasad Arun Kumar
- Human Genomics Laboratory, School of Chemical & Biotechnology, SASTRA University Thanjavur, Thanjavur 613 401, Tamil Nadu, India
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24
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Lin DS, Kao SH, Ho CS, Wei YH, Hung PL, Hsu MH, Wu TY, Wang TJ, Jian YR, Lee TH, Chiang MF. Inflexibility of AMPK-mediated metabolic reprogramming in mitochondrial disease. Oncotarget 2017; 8:73627-73639. [PMID: 29088732 PMCID: PMC5650287 DOI: 10.18632/oncotarget.20617] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 08/17/2017] [Indexed: 01/17/2023] Open
Abstract
Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is most commonly caused by the A3243G mutation of mitochondrial DNA. The capacity to utilize fatty acid or glucose as a fuel source and how such dynamic switches of metabolic fuel preferences and transcriptional modulation of adaptive mechanism in response to energy deficiency in MELAS syndrome have not been fully elucidated. The fibroblasts from patients with MELAS syndrome demonstrated a remarkable deficiency of electron transport chain complexes I and IV, an impaired cellular biogenesis under glucose deprivation, and a decreased ATP synthesis. In situ analysis of the bioenergetic properties of MELAS cells demonstrated an attenuated fatty acid oxidation that concomitantly occurred with impaired mitochondrial respiration, while energy production was mostly dependent on glycolysis. Furthermore, the transcriptional modulation was mediated by the AMP-activated protein kinase (AMPK) signaling pathway, which activated its downstream modulators leading to a subsequent increase in glycolytic flux through activation of pyruvate dehydrogenase. In contrast, the activities of carnitine palmitoyltransferase for fatty acid oxidation and acetyl-CoA carboxylase-1 for fatty acid synthesis were reduced and transcriptional regulation factors for biogenesis were not altered. These results provide novel information that MELAS cells lack the adaptive mechanism to switch fuel source from glucose to fatty acid, as glycolysis rates increase in response to energy deficiency. The aberrant secondary cellular responses to disrupted metabolic homeostasis mediated by AMPK signaling pathway may contribute to the development of the clinical phenotype.
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Affiliation(s)
- Dar-Shong Lin
- Department of Pediatrics, Mackay Memorial Hospital, Taipei, Taiwan.,Department of Medicine, Institute of Biomedical Sciences, Mackay Medical College, New Taipei, Taiwan
| | - Shu-Huei Kao
- School of Medical Laboratory Science and Biotechnology, Taipei Medical University, Taipei, Taiwan
| | - Che-Sheng Ho
- Department of Pediatrics, Mackay Memorial Hospital, Taipei, Taiwan
| | - Yau-Huei Wei
- Department of Medicine, Institute of Biomedical Sciences, Mackay Medical College, New Taipei, Taiwan.,Center for Mitochondrial Medicine and Free Radical Research, Changhua Christian Hospital, Changhua, Taiwan
| | - Pi-Lien Hung
- Department of Pediatric Neurology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Mei-Hsin Hsu
- Department of Pediatric Neurology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Tsu-Yen Wu
- Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan
| | - Tuan-Jen Wang
- Department of Laboratory Medicine, Mackay Memorial Hospital, Taipei, Taiwan
| | - Yuan-Ren Jian
- Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan
| | - Tsung-Han Lee
- Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan
| | - Ming-Fu Chiang
- Department of Neurosurgery, Mackay Memorial Hospital, Taipei, Taiwan.,Mackay Medicine, Nursing and Management College, Taipei, Taiwan.,Graduate Institute of Injury Prevention and Control, Taipei Medical University, Taipei, Taiwan
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25
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Zhu J, Yang P, Liu X, Yan L, Rampersad S, Li F, Li H, Sheng C, Cheng X, Zhang M, Qu S. The clinical characteristics of patients with mitochondrial tRNA Leu(UUR)m.3243A > G mutation: Compared with type 1 diabetes and early onset type 2 diabetes. J Diabetes Complications 2017; 31:1354-1359. [PMID: 28599824 DOI: 10.1016/j.jdiacomp.2017.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 03/09/2017] [Accepted: 04/03/2017] [Indexed: 12/22/2022]
Abstract
OBJECTIVE This study presents nine patients with mitochondrial tRNA Leu (UUR) m.3243A>G mutation and compares the clinical characteristics and diabetes complications with type 1 diabetes (T1DM) or early onset type 2 diabetes (T2DM). METHODS The study covers 9 patients with MIDD, 33 patients with T1DM and 86 patients (age of onset ≤35years) with early onset T2DM, matched for sex, age at onset of diabetes, duration of diabetes. All patients with MIDD were confirmed as carrying the m.3243A>G mitochondrial DNA mutation. Serum HbA1c, beta-cell function, retinal and renal complications of diabetes, bone metabolic markers, lumbar spine and femoral neck BMD bone mineral density were compared to characterize the clinical features of all patients. RESULTS Nine patients were from five unrelated families, and the mean (SD) onset age of those patients was 31.2±7.2year. Two patients required insulin at presentation, and six patients progressed to insulin requirement after a mean of 7.2years. β-Cell function in the MIDD group was intermediate between T1DM and early-onset T2DM. In MIDD, four patients were diagnosed as diabetic retinopathy (4/9) and five patients (5/9) had macroalbuminuria. The number of patients with diabetic retinopathy and macroalbuminuria in the MIDD group was comparable to T1DM or early-onset T2DM. The rate of osteoporosis (BMD T-score<-2.5 SD) in the patient with MIDD was higher than the T1DM or early-onset T2DM group. CONCLUSION Our study indicates that of the nine subjects with MIDD, three patients (1-II-1, 1-II-3, 1-II-4) who came from the same family had a history of acute pancreatitis. Compared with T1DM or early-onset T2DM matched for sex, age, duration of diabetes, MIDD patients had the highest rate of osteoporosis.
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MESH Headings
- Adult
- Age of Onset
- Biomarkers/blood
- Biomarkers/urine
- Bone Density
- China/epidemiology
- Deafness/complications
- Deafness/genetics
- Deafness/metabolism
- Deafness/physiopathology
- Diabetes Mellitus, Type 1/blood
- Diabetes Mellitus, Type 1/complications
- Diabetes Mellitus, Type 1/physiopathology
- Diabetes Mellitus, Type 1/urine
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/complications
- Diabetes Mellitus, Type 2/genetics
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/physiopathology
- Diabetes Mellitus, Type 2/urine
- Diabetic Nephropathies/epidemiology
- Diabetic Retinopathy/epidemiology
- Female
- Glycated Hemoglobin/analysis
- Humans
- Male
- Mitochondrial Diseases/complications
- Mitochondrial Diseases/genetics
- Mitochondrial Diseases/metabolism
- Mitochondrial Diseases/physiopathology
- Osteoporosis/complications
- Osteoporosis/epidemiology
- Pancreatitis/complications
- Pancreatitis/epidemiology
- Point Mutation
- Prevalence
- RNA, Transfer, Leu
- Young Adult
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Affiliation(s)
- Jie Zhu
- Department of Endocrinology & Metabolism, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Peng Yang
- Department of Endocrinology & Metabolism, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Xiang Liu
- Department of Urology, Putuo District People's Hospital, Shanghai 200060, China
| | - Li Yan
- Department of Endocrinology & Metabolism, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Sharvan Rampersad
- Department of Endocrinology & Metabolism, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Feng Li
- Department of Endocrinology & Metabolism, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Hong Li
- Department of Endocrinology & Metabolism, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Chunjun Sheng
- Department of Endocrinology & Metabolism, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Xiaoyun Cheng
- Department of Endocrinology & Metabolism, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Manna Zhang
- Department of Endocrinology & Metabolism, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, China.
| | - Shen Qu
- Department of Endocrinology & Metabolism, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, China
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Wang M, Peng Y, Zheng J, Zheng B, Jin X, Liu H, Wang Y, Tang X, Huang T, Jiang P, Guan MX. A deafness-associated tRNAAsp mutation alters the m1G37 modification, aminoacylation and stability of tRNAAsp and mitochondrial function. Nucleic Acids Res 2016; 44:10974-10985. [PMID: 27536005 PMCID: PMC5159531 DOI: 10.1093/nar/gkw726] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 08/05/2016] [Indexed: 02/04/2023] Open
Abstract
In this report, we investigated the pathogenic mechanism underlying the deafness-associated mitochondrial(mt) tRNAAsp 7551A > G mutation. The m.7551A > G mutation is localized at a highly conserved nucleotide(A37), adjacent (3′) to the anticodon, which is important for the fidelity of codon recognition and stabilization in functional tRNAs. It was anticipated that the m.7551A > G mutation altered the structure and function of mt-tRNAAsp. The primer extension assay demonstrated that the m.7551A > G mutation created the m1G37 modification of mt-tRNAAsp. Using cybrid cell lines generated by transferring mitochondria from lymphoblastoid cell lines derived from a Chinese family into mitochondrial DNA(mtDNA)-less (ρo) cells, we demonstrated the significant decreases in the efficiency of aminoacylation and steady-state level of mt-tRNAAsp in mutant cybrids, compared with control cybrids. A failure in metabolism of mt-tRNAAsp caused the variable reductions in mtDNA-encoded polypeptides in mutant cybrids. Impaired mitochondrial translation led to the respiratory phenotype in mutant cybrids. The respiratory deficiency lowed mitochondrial adenosine triphosphate production and increased the production of oxidative reactive species in mutant cybrids. Our data demonstrated that mitochondrial dysfunctions caused by the m.7551A > G mutation are associated with deafness. Our findings may provide new insights into the pathophysiology of maternally transmitted deafness that was manifested by altered nucleotide modification of mitochondrial tRNA.
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Affiliation(s)
- Meng Wang
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Yanyan Peng
- Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China.,Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Jing Zheng
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Binjiao Zheng
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang 325600, China
| | - Xiaofen Jin
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Hao Liu
- Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Yong Wang
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiaowen Tang
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang 325600, China
| | - Taosheng Huang
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Pingping Jiang
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China .,Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Min-Xin Guan
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China .,Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou, Zhejiang 310058, China
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27
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Wang M, Liu H, Zheng J, Chen B, Zhou M, Fan W, Wang H, Liang X, Zhou X, Eriani G, Jiang P, Guan MX. A Deafness- and Diabetes-associated tRNA Mutation Causes Deficient Pseudouridinylation at Position 55 in tRNAGlu and Mitochondrial Dysfunction. J Biol Chem 2016; 291:21029-21041. [PMID: 27519417 DOI: 10.1074/jbc.m116.739482] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Indexed: 02/03/2023] Open
Abstract
Several mitochondrial tRNA mutations have been associated with maternally inherited diabetes and deafness. However, the pathophysiology of these tRNA mutations remains poorly understood. In this report, we identified the novel homoplasmic 14692A→G mutation in the mitochondrial tRNAGlu gene among three Han Chinese families with maternally inherited diabetes and deafness. The m.14692A→G mutation affected a highly conserved uridine at position 55 of the TΨC loop of tRNAGlu The uridine is modified to pseudouridine (Ψ55), which plays an important role in the structure and function of this tRNA. Using lymphoblastoid cell lines derived from a Chinese family, we demonstrated that the m.14692A→G mutation caused loss of Ψ55 modification and increased angiogenin-mediated endonucleolytic cleavage in mutant tRNAGlu The destabilization of base-pairing (18A-Ψ55) caused by the m.14692A→G mutation perturbed the conformation and stability of tRNAGlu An approximately 65% decrease in the steady-state level of tRNAGlu was observed in mutant cells compared with control cells. A failure in tRNAGlu metabolism impaired mitochondrial translation, especially for polypeptides with a high proportion of glutamic acid codons such as ND1, ND6, and CO2 in mutant cells. An impairment of mitochondrial translation caused defective respiratory capacity, especially reducing the activities of complexes I and IV. Furthermore, marked decreases in the levels of mitochondrial ATP and membrane potential were observed in mutant cells. These mitochondrial dysfunctions caused an increasing production of reactive oxygen species in the mutant cells. Our findings may provide new insights into the pathophysiology of maternally inherited diabetes and deafness, which is primarily manifested by the deficient nucleotide modification of mitochondrial tRNAGlu.
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Affiliation(s)
- Meng Wang
- From the Division of Clinical Genetics and Genomics, Children's Hospital and the Institute of Genetics, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China 310001
| | - Hao Liu
- the Institute of Genetics, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China 310001
| | - Jing Zheng
- From the Division of Clinical Genetics and Genomics, Children's Hospital and the Institute of Genetics, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China 310001
| | - Bobei Chen
- the Department of Otolaryngology, Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China 325035, the Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China 325035
| | - Mi Zhou
- From the Division of Clinical Genetics and Genomics, Children's Hospital and the Institute of Genetics, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China 310001
| | - Wenlu Fan
- the Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China 325035
| | - Hen Wang
- the Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China 325035
| | - Xiaoyang Liang
- From the Division of Clinical Genetics and Genomics, Children's Hospital and the Institute of Genetics, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China 310001
| | - Xiaolong Zhou
- the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China 200031, and
| | - Gilbert Eriani
- the Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, Institut de Biologie Moléculaire et Cellulaire, 15 rue René Descartes, 67084 Strasbourg, France
| | - Pingping Jiang
- From the Division of Clinical Genetics and Genomics, Children's Hospital and the Institute of Genetics, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China 310001
| | - Min-Xin Guan
- From the Division of Clinical Genetics and Genomics, Children's Hospital and the Institute of Genetics, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China 310001, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, and Joining Institute of Genetics and Genomic Medicine between Zhejiang University and University of Toronto, Zhejiang University, Hangzhou, Zhejiang, China 310058,
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28
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Jiang P, Liang M, Zhang C, Zhao X, He Q, Cui L, Liu X, Sun YH, Fu Q, Ji Y, Bai Y, Huang T, Guan MX. Biochemical evidence for a mitochondrial genetic modifier in the phenotypic manifestation of Leber's hereditary optic neuropathy-associated mitochondrial DNA mutation. Hum Mol Genet 2016; 25:3613-3625. [PMID: 27427386 DOI: 10.1093/hmg/ddw199] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 06/08/2016] [Accepted: 06/21/2016] [Indexed: 02/01/2023] Open
Abstract
Leber's hereditary optic neuropathy (LHON) is the most common mitochondrial disease. Mitochondrial modifiers are proposed to modify the phenotypic expression of primary LHON-associated mitochondrial DNA (mtDNA) mutations. In this study, we demonstrated that the LHON susceptibility allele (m.14502T > C, p. 58I > V) in the ND6 gene modulated the phenotypic expression of primary LHON-associated m.11778G > A mutation. Twenty-two Han Chinese pedigrees carrying m.14502T > C and m.11778G > A mutations exhibited significantly higher penetrance of optic neuropathy than those carrying only m.11778G > A mutation. We performed functional assays using the cybrid cell models, generated by fusing mtDNA-less ρo cells with enucleated cells from LHON patients carrying both m.11778G > A and m.14502T > C mutations, only m.14502T > C or m.11778G > A mutation and a control belonging to the same mtDNA haplogroup. These cybrids cell lines bearing m.14502T > C mutation exhibited mild effects on mitochondrial functions compared with those carrying only m.11778G > A mutation. However, more severe mitochondrial dysfunctions were observed in cell lines bearing both m.14502T > C and m.11778G > A mutations than those carrying only m.11778G > A or m.14502T > C mutation. In particular, the m.14502T > C mutation altered assemble of complex I, thereby aggravating the respiratory phenotypes associated with m.11778G > A mutation, resulted in a more defective complex I. Furthermore, more reductions in the levels of mitochondrial ATP and increasing production of reactive oxygen species were also observed in mutant cells bearing both m.14502T > C and m.11778G > A mutation than those carrying only 11778G > A mutation. Our findings provided new insights into the pathophysiology of LHON that were manifested by interaction between primary and secondary mtDNA mutations.
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Affiliation(s)
- Pingping Jiang
- Divsion of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.,Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Min Liang
- Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Department of Clinical Laboratory, The First Affiliated Hospital.,School of Ophthalmology and Optometry
| | - Chaofan Zhang
- Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Xiaoxu Zhao
- Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Qiufen He
- Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Limei Cui
- Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Xiaoling Liu
- School of Ophthalmology and Optometry.,Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Yan-Hong Sun
- Department of Ophthalmology, Beijing University of Chinese Medicine and Pharmacology, Beijing 100029, China
| | - Qun Fu
- Department of Ophthalmology, The Third Affiliated Hospital, Xinxiang Medical College, Xinxiang, Henan 45300, China
| | - Yanchun Ji
- Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Yidong Bai
- Department of Cellular & Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Taosheng Huang
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, OH 45229, USA
| | - Min-Xin Guan
- Divsion of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China .,Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Joining Institute of Genetics and Genomic Medicine between Zhejiang University and University of Toronto, Hangzhou, Zhejiang 310058, China
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29
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A Hypertension-Associated tRNAAla Mutation Alters tRNA Metabolism and Mitochondrial Function. Mol Cell Biol 2016; 36:1920-30. [PMID: 27161322 PMCID: PMC4936059 DOI: 10.1128/mcb.00199-16] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 05/04/2016] [Indexed: 01/11/2023] Open
Abstract
In this report, we investigated the pathophysiology of a novel hypertension-associated mitochondrial tRNAAla 5655A → G (m.5655A → G) mutation. The destabilization of a highly conserved base pairing (A1-U72) at the aminoacyl acceptor stem by an m.5655A → G mutation altered the tRNAAla function. An in vitro processing analysis showed that the m.5655A → G mutation reduced the efficiency of tRNAAla precursor 5′ end cleavage catalyzed by RNase P. By using cybrids constructed by transferring mitochondria from lymphoblastoid cell lines derived from a Chinese family into mitochondrial DNA (mtDNA)-less (ρo) cells, we showed a 41% reduction in the steady-state level of tRNAAla in mutant cybrids. The mutation caused an improperly aminoacylated tRNAAla, as suggested by aberrantly aminoacylated tRNAAla and slower electrophoretic mobility of mutated tRNA. A failure in tRNAAla metabolism contributed to variable reductions in six mtDNA-encoded polypeptides in mutant cells, ranging from 21% to 37.5%, with an average of a 29.1% reduction, compared to levels of the controls. The impaired translation caused reduced activities of mitochondrial respiration chains. Furthermore, marked decreases in the levels of mitochondrial ATP and membrane potential were observed in mutant cells. These caused increases in the production of reactive oxygen species in the mutant cybrids. The data provide evidence for the association of the tRNAAla 5655A → G mutation with hypertension.
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30
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McKenzie M, Duchen MR. Impaired Cellular Bioenergetics Causes Mitochondrial Calcium Handling Defects in MT-ND5 Mutant Cybrids. PLoS One 2016; 11:e0154371. [PMID: 27110715 PMCID: PMC4844100 DOI: 10.1371/journal.pone.0154371] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 04/12/2016] [Indexed: 11/18/2022] Open
Abstract
Mutations in mitochondrial DNA (mtDNA) can cause mitochondrial disease, a group of metabolic disorders that affect both children and adults. Interestingly, individual mtDNA mutations can cause very different clinical symptoms, however the factors that determine these phenotypes remain obscure. Defects in mitochondrial oxidative phosphorylation can disrupt cell signaling pathways, which may shape these disease phenotypes. In particular, mitochondria participate closely in cellular calcium signaling, with profound impact on cell function. Here, we examined the effects of a homoplasmic m.13565C>T mutation in MT-ND5 on cellular calcium handling using transmitochondrial cybrids (ND5 mutant cybrids). We found that the oxidation of NADH and mitochondrial membrane potential (Δψm) were significantly reduced in ND5 mutant cybrids. These metabolic defects were associated with a significant decrease in calcium uptake by ND5 mutant mitochondria in response to a calcium transient. Inhibition of glycolysis with 2-deoxy-D-glucose did not affect cytosolic calcium levels in control cybrids, but caused an increase in cytosolic calcium in ND5 mutant cybrids. This suggests that glycolytically-generated ATP is required not only to maintain Δψm in ND5 mutant mitochondria but is also critical for regulating cellular calcium homeostasis. We conclude that the m.13565C>T mutation in MT-ND5 causes defects in both mitochondrial oxidative metabolism and mitochondrial calcium sequestration. This disruption of mitochondrial calcium handling, which leads to defects in cellular calcium homeostasis, may be an important contributor to mitochondrial disease pathogenesis.
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Affiliation(s)
- Matthew McKenzie
- Centre for Genetic Diseases, Hudson Institute of Medical Research, Clayton, Melbourne, Victoria 3168, Australia
- The Department of Molecular and Translational Science, Monash University, Clayton, Melbourne, Victoria 3168, Australia
- * E-mail:
| | - Michael R. Duchen
- Department of Physiology, University College London, Gower St, London, UK WC1E6BT
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31
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Ninomiya H, Hirata A, Kozawa J, Nakata S, Kimura T, Kitamura T, Yasuda T, Otsuki M, Imagawa A, Kaneto H, Funahashi T, Shimomura I. Treatment of Mitochondrial Diabetes with a Peroxisome Proliferator-activated Receptor (PPAR)-gamma Agonist. Intern Med 2016; 55:1143-7. [PMID: 27150869 DOI: 10.2169/internalmedicine.55.4418] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The 3243 A>G mutation in mitochondrial DNA is the most common cause of monogenic diabetes mellitus in Japan. A 45-year-old woman with mitochondrial diabetes and significant insulin resistance presented with hypoadiponectinemia despite a normal amount of visceral fat. Three months of treatment with pioglitazone (PIO) improved her blood glucose profile and response to the 75-g oral glucose tolerance test. These changes were accompanied by the amelioration of her insulin resistance and the impairment of early-phase insulin secretion. Her serum adiponectin levels increased to the normal range. In this case of mitochondrial diabetes, PIO was effective for glycemic control.
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Affiliation(s)
- Hiroyo Ninomiya
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Japan
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32
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Lindroos MM, Pärkkä JP, Taittonen MT, Iozzo P, Kärppä M, Hassinen IE, Knuuti J, Nuutila P, Majamaa K. Myocardial glucose uptake in patients with the m.3243A > G mutation in mitochondrial DNA. J Inherit Metab Dis 2016; 39:67-74. [PMID: 26112752 DOI: 10.1007/s10545-015-9865-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Revised: 05/14/2015] [Accepted: 05/18/2015] [Indexed: 10/23/2022]
Abstract
Mitochondrial mutations impair glucose oxidation and increase glucose uptake in cell cultures and lead to cardiomyopathy in patients. Here we characterize cardiac glucose uptake in 14 patients with the m.3243A > G mutation in mitochondrial DNA. The 14 patients with m.3243A > G and 13 controls were similar in age, physical activity and body mass index. Ten patients had diabetes. Left ventricular glucose uptake per tissue mass (LVGU) was measured with 2-[(18) F]fluoro-2-deoxyglucose positron emission tomography during euglycemic hyperinsulinemia. Cardiac morphology and function were assessed with magnetic resonance imaging. We found that the LVGU was 25% lower in the patients than that in the controls (P = 0.029). LVGU was inversely correlated with mutation heteroplasmy, glycated haemoglobin and fasting lactate in patients. The seven patients with mutation heteroplasmy ≥ 49% had 44% lower LVGU than the seven patients with heteroplasmy < 49%. This difference remained significant after adjustment for concurrent free fatty acid concentration or glycated haemoglobin or glucose uptake in skeletal muscle or all (p < 0.048 [All]). Patients with m.3243A > G had a lower stroke volume and a higher heart rate than the controls, whereas cardiac output and work were similar. Myocardial glucose uptake is not increased but decreased with a threshold effect pattern in patients with the m.3243A > G mutation. The glucose hypometabolism adds to the impaired cardiac energetics and likely contributes to the progression of the mitochondrial cardiomyopathy.
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Affiliation(s)
| | - Jussi P Pärkkä
- Department of Clinical Physiology, Turku University Hospital, Turku, Finland
| | - Markku T Taittonen
- Department of Anaesthesiology, Turku University Hospital, Turku, Finland
| | - Patricia Iozzo
- Institute of Clinical Physiology, National Research Council (CNR), Pisa, Italy
| | - Mikko Kärppä
- Research Group of Clinical Neuroscience, Neurology, University of Oulu, P.O Box 5000, FIN-90014, Oulu, Finland
- Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Ilmo E Hassinen
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Juhani Knuuti
- Turku PET Centre, University of Turku, Turku, Finland
| | - Pirjo Nuutila
- Turku PET Centre, University of Turku, Turku, Finland
- Department of Endocrinology, Turku University Hospital, Turku, Finland
| | - Kari Majamaa
- Research Group of Clinical Neuroscience, Neurology, University of Oulu, P.O Box 5000, FIN-90014, Oulu, Finland.
- Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland.
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Functional hyperspectral imaging captures subtle details of cell metabolism in olfactory neurosphere cells, disease-specific models of neurodegenerative disorders. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:56-63. [PMID: 26431992 DOI: 10.1016/j.bbamcr.2015.09.030] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 08/17/2015] [Accepted: 09/25/2015] [Indexed: 12/26/2022]
Abstract
Hyperspectral imaging uses spectral and spatial image information for target detection and classification. In this work hyperspectral autofluorescence imaging was applied to patient olfactory neurosphere-derived cells, a cell model of a human metabolic disease MELAS (mitochondrial myopathy, encephalomyopathy, lactic acidosis, stroke-like syndrome). By using an endogenous source of contrast subtle metabolic variations have been detected between living cells in their full morphological context which made it possible to distinguish healthy from diseased cells before and after therapy. Cellular maps of native fluorophores, flavins, bound and free NADH and retinoids unveiled subtle metabolic signatures and helped uncover significant cell subpopulations, in particular a subpopulation with compromised mitochondrial function. Taken together, our results demonstrate that multispectral spectral imaging provides a new non-invasive method to investigate neurodegenerative and other disease models, and it paves the way for novel cellular characterisation in health, disease and during treatment, with proper account of intrinsic cellular heterogeneity.
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Mitochondrial degradation and energy metabolism. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:2812-21. [DOI: 10.1016/j.bbamcr.2015.05.010] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 04/23/2015] [Accepted: 05/07/2015] [Indexed: 12/14/2022]
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Garrido-Maraver J, Paz MV, Cordero MD, Bautista-Lorite J, Oropesa-Ávila M, de la Mata M, Pavón AD, de Lavera I, Alcocer-Gómez E, Galán F, Ybot González P, Cotán D, Jackson S, Sánchez-Alcázar JA. Critical role of AMP-activated protein kinase in the balance between mitophagy and mitochondrial biogenesis in MELAS disease. Biochim Biophys Acta Mol Basis Dis 2015; 1852:2535-53. [PMID: 26341273 DOI: 10.1016/j.bbadis.2015.08.027] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 08/03/2015] [Accepted: 08/31/2015] [Indexed: 10/23/2022]
Affiliation(s)
- Juan Garrido-Maraver
- Centro Andaluz de Biología del Desarrollo (CABD), Instituto de Salud Carlos III, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Sevilla 41013, Spain; Centro de Investigación Biomédica en Red: Enfermedades Raras, Instituto de Salud Carlos III, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Sevilla 41013, Spain
| | - Marina Villanueva Paz
- Centro Andaluz de Biología del Desarrollo (CABD), Instituto de Salud Carlos III, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Sevilla 41013, Spain; Centro de Investigación Biomédica en Red: Enfermedades Raras, Instituto de Salud Carlos III, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Sevilla 41013, Spain
| | - Mario D Cordero
- Facultad de Odontología, Universidad de Sevilla, Sevilla, Spain
| | | | - Manuel Oropesa-Ávila
- Centro Andaluz de Biología del Desarrollo (CABD), Instituto de Salud Carlos III, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Sevilla 41013, Spain; Centro de Investigación Biomédica en Red: Enfermedades Raras, Instituto de Salud Carlos III, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Sevilla 41013, Spain
| | - Mario de la Mata
- Centro Andaluz de Biología del Desarrollo (CABD), Instituto de Salud Carlos III, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Sevilla 41013, Spain; Centro de Investigación Biomédica en Red: Enfermedades Raras, Instituto de Salud Carlos III, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Sevilla 41013, Spain
| | - Ana Delgado Pavón
- Centro Andaluz de Biología del Desarrollo (CABD), Instituto de Salud Carlos III, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Sevilla 41013, Spain; Centro de Investigación Biomédica en Red: Enfermedades Raras, Instituto de Salud Carlos III, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Sevilla 41013, Spain
| | - Isabel de Lavera
- Centro Andaluz de Biología del Desarrollo (CABD), Instituto de Salud Carlos III, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Sevilla 41013, Spain; Centro de Investigación Biomédica en Red: Enfermedades Raras, Instituto de Salud Carlos III, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Sevilla 41013, Spain
| | - Elizabet Alcocer-Gómez
- Centro Andaluz de Biología del Desarrollo (CABD), Instituto de Salud Carlos III, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Sevilla 41013, Spain; Centro de Investigación Biomédica en Red: Enfermedades Raras, Instituto de Salud Carlos III, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Sevilla 41013, Spain
| | | | - Patricia Ybot González
- Instituto de Biomedicina de Sevilla (IBIS)-CSIC, Hospital Virgen del Rocío, Sevilla, Spain
| | - David Cotán
- Centro Andaluz de Biología del Desarrollo (CABD), Instituto de Salud Carlos III, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Sevilla 41013, Spain; Centro de Investigación Biomédica en Red: Enfermedades Raras, Instituto de Salud Carlos III, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Sevilla 41013, Spain
| | - Sandra Jackson
- Department of Neurology, Uniklinikum C. G. Carus, Dresden, Germany
| | - José A Sánchez-Alcázar
- Centro Andaluz de Biología del Desarrollo (CABD), Instituto de Salud Carlos III, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Sevilla 41013, Spain; Centro de Investigación Biomédica en Red: Enfermedades Raras, Instituto de Salud Carlos III, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Sevilla 41013, Spain.
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Gong S, Peng Y, Jiang P, Wang M, Fan M, Wang X, Zhou H, Li H, Yan Q, Huang T, Guan MX. A deafness-associated tRNAHis mutation alters the mitochondrial function, ROS production and membrane potential. Nucleic Acids Res 2014; 42:8039-48. [PMID: 24920829 PMCID: PMC4081083 DOI: 10.1093/nar/gku466] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
In this report, we investigated the molecular genetic mechanism underlying the deafness-associated mitochondrial tRNAHis 12201T>C mutation. The destabilization of a highly conserved base-pairing (5A-68U) by the m.12201T>C mutation alters structure and function of tRNAHis. Using cybrids constructed by transferring mitochondria from lymphoblastoid cell lines derived from a Chinese family into mtDNA-less (ρo) cells, we showed ∼70% decrease in the steady-state level of tRNAHis in mutant cybrids, compared with control cybrids. The mutation changed the conformation of tRNAHis, as suggested by slower electrophoretic mobility of mutated tRNA with respect to the wild-type molecule. However, ∼60% increase in aminoacylated level of tRNAHis was observed in mutant cells. The failure in tRNAHis metabolism was responsible for the variable reductions in seven mtDNA-encoded polypeptides in mutant cells, ranging from 37 to 81%, with the average of ∼46% reduction, as compared with those of control cells. The impaired mitochondrial translation caused defects in respiratory capacity in mutant cells. Furthermore, marked decreases in the levels of mitochondrial ATP and membrane potential were observed in mutant cells. These mitochondrial dysfunctions caused an increase in the production of reactive oxygen species in the mutant cells. The data provide the evidence for a mitochondrial tRNAHis mutation leading to deafness.
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Affiliation(s)
- Shasha Gong
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China 310058
| | - Yanyan Peng
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China 310058 Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA 45229
| | - Pingping Jiang
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China 310058
| | - Meng Wang
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China 310058
| | - Mingjie Fan
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China 310058
| | - Xinjian Wang
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA 45229
| | - Hong Zhou
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China 310058
| | - Huawei Li
- Department of Otology and Skull Base Surgery, Eye and ENT Hospital, Fudan University, Shanghai, China 200031
| | - Qingfeng Yan
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China 310058
| | - Taosheng Huang
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA 45229
| | - Min-Xin Guan
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China 310058 Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA 45229
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Tavira B, Gómez J, Díaz-Corte C, Llobet L, Ruiz-Pesini E, Ortega F, Coto E. Mitochondrial DNA haplogroups and risk of new-onset diabetes among tacrolimus-treated renal transplanted patients. Gene 2014; 538:195-8. [PMID: 24445060 DOI: 10.1016/j.gene.2014.01.036] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 12/21/2013] [Accepted: 01/13/2014] [Indexed: 12/17/2022]
Abstract
BACKGROUND AND AIMS Tacrolimus (Tac) is an immunosuppressive drug widely used to avoid organ rejection. New-onset diabetes after transplantation (NODAT) is a major complication among transplanted patients who receive Tac. The increased risk for NODAT could be partly mediated by the effect of Tac on mitochondria from pancreatic beta-cells. Common and rare mitochondrial DNA variants have been linked to the risk of diabetes. Our aim was to determine whether mtDNA polymorphisms/haplogroups were associated with NODAT in Tac-treated kidney transplanted. METHODS Seven polymorphisms that define the common European haplogroups were determined in 115 NODAT and 197 no-NODAT patients. RESULTS Haplogroup H was significantly more frequent in the NODAT group (50% vs. 35%; p=0.01, OR=1.82). There was no difference between patients without and with (n=106) D2M prior to the transplant. CONCLUSIONS Mitochondrial haplogroup H was associated with the risk for NODAT among Tac-treated transplanted patients. The reported differences between the mtDNA variants could explain the increased NODAT-risk among H-patients.
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Affiliation(s)
- Beatriz Tavira
- Genética Molecular, Hospital Universitario Central de Asturias (HUCA), Oviedo, Spain
| | - Juan Gómez
- Genética Molecular, Hospital Universitario Central de Asturias (HUCA), Oviedo, Spain
| | - Carmen Díaz-Corte
- Nefrología, Hospital Universitario Central de Asturias (HUCA), Oviedo, Spain
| | - Laura Llobet
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain; Centro de Investigaciones Biomédicas En Red de Enfermedades Raras (CIBERER), Universidad de Zaragoza, Zaragoza, Spain
| | - Eduardo Ruiz-Pesini
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain; Centro de Investigaciones Biomédicas En Red de Enfermedades Raras (CIBERER), Universidad de Zaragoza, Zaragoza, Spain
| | - Francisco Ortega
- Nefrología, Hospital Universitario Central de Asturias (HUCA), Oviedo, Spain; Fundación Renal I. Alvarez de Toledo, Madrid, Spain
| | - Eliecer Coto
- Genética Molecular, Hospital Universitario Central de Asturias (HUCA), Oviedo, Spain; Fundación Renal I. Alvarez de Toledo, Madrid, Spain; Universidad de Oviedo, Oviedo, Spain.
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Supale S, Thorel F, Merkwirth C, Gjinovci A, Herrera PL, Scorrano L, Meda P, Langer T, Maechler P. Loss of prohibitin induces mitochondrial damages altering β-cell function and survival and is responsible for gradual diabetes development. Diabetes 2013; 62:3488-99. [PMID: 23863811 PMCID: PMC3781460 DOI: 10.2337/db13-0152] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Prohibitins are highly conserved proteins mainly implicated in the maintenance of mitochondrial function and architecture. Their dysfunctions are associated with aging, cancer, obesity, and inflammation. However, their possible role in pancreatic β-cells remains unknown. The current study documents the expression of prohibitins in human and rodent islets and their key role for β-cell function and survival. Ablation of Phb2 in mouse β-cells sequentially resulted in impairment of mitochondrial function and insulin secretion, loss of β-cells, progressive alteration of glucose homeostasis, and, ultimately, severe diabetes. Remarkably, these events progressed over a 3-week period of time after weaning. Defective insulin supply in β-Phb2(-/-) mice was contributed by both β-cell dysfunction and apoptosis, temporarily compensated by increased β-cell proliferation. At the molecular level, we observed that deletion of Phb2 caused mitochondrial abnormalities, including reduction of mitochondrial DNA copy number and respiratory chain complex IV levels, altered mitochondrial activity, cleavage of L-optic atrophy 1, and mitochondrial fragmentation. Overall, our data demonstrate that Phb2 is essential for metabolic activation of mitochondria and, as a consequence, for function and survival of β-cells.
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Affiliation(s)
- Sachin Supale
- Department of Cell Physiology and Metabolism, University of Geneva Medical Centre, Geneva, Switzerland
| | - Fabrizio Thorel
- Department of Genetic Medicine and Development, University of Geneva Medical Centre, Geneva, Switzerland
| | | | - Asllan Gjinovci
- Department of Cell Physiology and Metabolism, University of Geneva Medical Centre, Geneva, Switzerland
| | - Pedro L. Herrera
- Department of Genetic Medicine and Development, University of Geneva Medical Centre, Geneva, Switzerland
| | - Luca Scorrano
- Department of Cell Physiology and Metabolism, University of Geneva Medical Centre, Geneva, Switzerland
| | - Paolo Meda
- Department of Cell Physiology and Metabolism, University of Geneva Medical Centre, Geneva, Switzerland
| | - Thomas Langer
- Institute for Genetics, University of Cologne, Cologne, Germany
| | - Pierre Maechler
- Department of Cell Physiology and Metabolism, University of Geneva Medical Centre, Geneva, Switzerland
- Corresponding author: Pierre Maechler,
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Garrido-Maraver J, Cordero MD, Moñino ID, Pereira-Arenas S, Lechuga-Vieco AV, Cotán D, De la Mata M, Oropesa-Ávila M, De Miguel M, Bautista Lorite J, Rivas Infante E, Alvarez-Dolado M, Navas P, Jackson S, Francisci S, Sánchez-Alcázar JA. Screening of effective pharmacological treatments for MELAS syndrome using yeasts, fibroblasts and cybrid models of the disease. Br J Pharmacol 2013; 167:1311-28. [PMID: 22747838 DOI: 10.1111/j.1476-5381.2012.02086.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE MELAS (mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes) is a mitochondrial disease most usually caused by point mutations in tRNA genes encoded by mitochondrial DNA (mtDNA). Approximately 80% of cases of MELAS syndrome are associated with a m.3243A > G mutation in the MT-TL1 gene, which encodes the mitochondrial tRNALeu (UUR). Currently, no effective treatments are available for this chronic progressive disorder. Treatment strategies in MELAS and other mitochondrial diseases consist of several drugs that diminish the deleterious effects of the abnormal respiratory chain function, reduce the presence of toxic agents or correct deficiencies in essential cofactors. EXPERIMENTAL APPROACH We evaluated the effectiveness of some common pharmacological agents that have been utilized in the treatment of MELAS, in yeast, fibroblast and cybrid models of the disease. The yeast model harbouring the A14G mutation in the mitochondrial tRNALeu(UUR) gene, which is equivalent to the A3243G mutation in humans, was used in the initial screening. Next, the most effective drugs that were able to rescue the respiratory deficiency in MELAS yeast mutants were tested in fibroblasts and cybrid models of MELAS disease. KEY RESULTS According to our results, supplementation with riboflavin or coenzyme Q(10) effectively reversed the respiratory defect in MELAS yeast and improved the pathologic alterations in MELAS fibroblast and cybrid cell models. CONCLUSIONS AND IMPLICATIONS Our results indicate that cell models have great potential for screening and validating the effects of novel drug candidates for MELAS treatment and presumably also for other diseases with mitochondrial impairment.
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Affiliation(s)
- Juan Garrido-Maraver
- Centro Andaluz de Biología del Desarrollo (CABD) and Centro de Investigación Biomédica en Red: Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas-Junta de Andalucía, Sevilla, Spain
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Supale S, Li N, Brun T, Maechler P. Mitochondrial dysfunction in pancreatic β cells. Trends Endocrinol Metab 2012; 23:477-87. [PMID: 22766318 DOI: 10.1016/j.tem.2012.06.002] [Citation(s) in RCA: 182] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 06/02/2012] [Accepted: 06/02/2012] [Indexed: 12/17/2022]
Abstract
In pancreatic β cells, mitochondria play a central role in coupling glucose metabolism to insulin exocytosis, thereby ensuring strict control of glucose-stimulated insulin secretion. Defects in mitochondrial function impair this metabolic coupling, and ultimately promote apoptosis and β cell death. Various factors have been identified that may contribute to mitochondrial dysfunction. In this review we address the emerging concept of complex links between these factors. We also discuss the role of the mitochondrial genome and mutations associated with diabetes, the effect of oxidative stress and reactive oxygen species, the sensitivity of mitochondria to lipotoxicity, and the adaptive dynamics of mitochondrial morphology. Better comprehension of the molecular mechanisms contributing to mitochondrial dysfunction will help drive the development of effective therapeutic approaches.
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Affiliation(s)
- Sachin Supale
- Department of Cell Physiology and Metabolism, University of Geneva Medical Centre, 1211 Geneva 4, Switzerland
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Williams TB, Daniels M, Puthenveetil G, Chang R, Wang RY, Abdenur JE. Pearson syndrome: unique endocrine manifestations including neonatal diabetes and adrenal insufficiency. Mol Genet Metab 2012; 106:104-7. [PMID: 22424738 DOI: 10.1016/j.ymgme.2012.01.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 01/20/2012] [Accepted: 01/20/2012] [Indexed: 10/14/2022]
Abstract
PURPOSE Pearson syndrome is a very rare metabolic disorder that is usually present in infancy with transfusion dependent macrocytic anemia and multiorgan involvement including exocrine pancreas, liver and renal tubular defects. The disease is secondary to a mitochondrial DNA deletion that is variable in size and location. Endocrine abnormalities can develop, but are usually not part of the initial presentation. We report two patients who presented with unusual endocrine manifestations, neonatal diabetes and adrenal insufficiency, who were both later diagnosed with Pearson syndrome. METHODS Medical records were reviewed. Confirmatory testing included: mitochondrial DNA deletion testing and sequencing of the breakpoints, muscle biopsy, and bone marrow studies. RESULTS Case 1 presented with hyperglycemia requiring insulin at birth. She had several episodes of ketoacidosis triggered by stress and labile blood glucose control. Workup for genetic causes of neonatal diabetes was negative. She had transfusion dependent anemia and died at 24 months due to multisystem organ failure. Case 2 presented with adrenal insufficiency and anemia during inturcurrent illness, requiring steroid replacement since 37 months of age. He is currently 4 years old and has mild anemia. Mitochondrial DNA studies confirmed a 4.9 kb deletion in patient 1 and a 5.1 kb deletion in patient 2. CONCLUSION The patients reported highlight the importance of considering mitochondrial DNA disorders in patients with early onset endocrine dysfunction, and expand the knowledge about this rare mitochondrial disease.
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Affiliation(s)
- T B Williams
- Division of Metabolic Disorders, CHOC Children's, Orange, CA 92868, USA
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Szczepanowska J, Malinska D, Wieckowski MR, Duszynski J. Effect of mtDNA point mutations on cellular bioenergetics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1740-6. [PMID: 22406627 DOI: 10.1016/j.bbabio.2012.02.028] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 02/13/2012] [Accepted: 02/14/2012] [Indexed: 10/28/2022]
Abstract
This overview discusses the results of research on the effects of most frequent mtDNA point mutations on cellular bioenergetics. Thirteen proteins coded by mtDNA are crucial for oxidative phosphorylation, 11 of them constitute key components of the respiratory chain complexes I, III and IV and 2 of mitochondrial ATP synthase. Moreover, pathogenic point mutations in mitochondrial tRNAs and rRNAs generate abnormal synthesis of the mtDNA coded proteins. Thus, pathogenic point mutations in mtDNA usually disturb the level of key parameter of the oxidative phosphorylation, i.e. the electric potential on the inner mitochondrial membrane (Δψ), and in a consequence calcium signalling and mitochondrial dynamics in the cell. Mitochondrial generation of reactive oxygen species is also modified in the mutated cells. The results obtained with cultured cells and describing biochemical consequences of mtDNA point mutations are full of contradictions. Still they help elucidate the biochemical basis of pathologies and provide a valuable tool for finding remedies in the future. This article is part of a Special Issue entitled: 17th European Bioenergetics Conference (EBEC 2012).
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Affiliation(s)
- Joanna Szczepanowska
- Department of Biochemsitry, Nencki Institute of Experimental Biology, Warsaw, Poland
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Mitochondrial DNA polymerase editing mutation, PolgD257A, reduces the diabetic phenotype of Akita male mice by suppressing appetite. Proc Natl Acad Sci U S A 2011; 108:8779-84. [PMID: 21555558 DOI: 10.1073/pnas.1106344108] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Diabetes and the development of its complications have been associated with mitochondrial DNA (mtDNA) dysfunction, but causal relationships remain undetermined. With the objective of testing whether increased mtDNA mutations exacerbate the diabetic phenotype, we have compared mice heterozygous for the Akita diabetogenic mutation (Akita) with mice homozygous for the D257A mutation in mitochondrial DNA polymerase gamma (Polg) or with mice having both mutations (Polg-Akita). The Polg-D257A protein is defective in proofreading and increases mtDNA mutations. At 3 mo of age, the Polg-Akita and Akita male mice were equally hyperglycemic. Unexpectedly, as the Polg-Akita males aged to 9 mo, their diabetic symptoms decreased. Thus, their hyperglycemia, hyperphagia and urine output declined significantly. The decrease in their food intake was accompanied by increased plasma leptin and decreased plasma ghrelin, while hypothalamic expression of the orexic gene, neuropeptide Y, was lower and expression of the anorexic gene, proopiomelanocortin, was higher. Testis function progressively worsened with age in the double mutants, and plasma testosterone levels in 9-mo-old Polg-Akita males were significantly reduced compared with Akita males. The hyperglycemia and hyperphagia returned in aged Polg-Akita males after testosterone administration. Hyperglycemia-associated distal tubular damage in the kidney also returned, and Polg-D257A-associated proximal tubular damage was enhanced. The mild diabetes of female Akita mice was not affected by the Polg-D257A mutation. We conclude that reduced diabetic symptoms of aging Polg-Akita males results from appetite suppression triggered by decreased testosterone associated with damage to the Leydig cells of the testis.
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Cotán D, Cordero MD, Garrido-Maraver J, Oropesa-Ávila M, Rodríguez-Hernández A, Gómez Izquierdo L, De la Mata M, De Miguel M, Lorite JB, Infante ER, Jackson S, Navas P, Sánchez-Alcázar JA. Secondary coenzyme Q10 deficiency triggers mitochondria degradation by mitophagy in MELAS fibroblasts. FASEB J 2011; 25:2669-87. [PMID: 21551238 DOI: 10.1096/fj.10-165340] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is a mitochondrial disease most usually caused by point mutations in tRNA genes encoded by mtDNA. Here, we report on how this mutation affects mitochondrial function in primary fibroblast cultures established from 2 patients with MELAS who harbored the A3243G mutation. Both mitochondrial respiratory chain enzyme activities and coenzyme Q(10) (CoQ) levels were significantly decreased in MELAS fibroblasts. A similar decrease in mitochondrial membrane potential was found in intact MELAS fibroblasts. Mitochondrial dysfunction was associated with increased oxidative stress and the activation of mitochondrial permeability transition (MPT), which triggered the degradation of impaired mitochondria. Furthermore, we found defective autophagosome elimination in MELAS fibroblasts. Electron and fluorescence microscopy studies confirmed a massive degradation of mitochondria and accumulation of autophagosomes, suggesting mitophagy activation and deficient autophagic flux. Transmitochondrial cybrids harboring the A3243G mutation also showed CoQ deficiency and increased autophagy activity. All these abnormalities were partially restored by CoQ supplementation. Autophagy in MELAS fibroblasts was also abolished by treatment with antioxidants or cyclosporine, suggesting that both reactive oxygen species and MPT participate in this process. Furthermore, prevention of autophagy in MELAS fibroblasts resulted in apoptotic cell death, suggesting a protective role of autophagy in MELAS fibroblasts.
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Affiliation(s)
- David Cotán
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Sevilla 41013, Spain
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Mitra RC, Zhang Z, Alexov E. In silico modeling of pH-optimum of protein-protein binding. Proteins 2010; 79:925-36. [PMID: 21287623 DOI: 10.1002/prot.22931] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Revised: 10/12/2010] [Accepted: 10/29/2010] [Indexed: 01/05/2023]
Abstract
Protein-protein association is a pH-dependent process and thus the binding affinity depends on the local pH. In vivo the association occurs in a particular cellular compartment, where the individual monomers are supposed to meet and form a complex. Since the monomers and the complex exist in the same micro environment, it is plausible that they coevolved toward its properties, in particular, toward the characteristic subcellular pH. Here we show that the pH at which the monomers are most stable (pH-optimum) or the pH at which stability is almost pH-independent (pH-flat) of monomers are correlated with the pH-optimum of maximal affinity (pH-optimum of binding) or pH interval at which affinity is almost pH-independent (pH-flat of binding) of the complexes made of the corresponding monomers. The analysis of interfacial properties of protein complexes demonstrates that pH-dependent properties can be roughly estimated using the interface charge alone. In addition, we introduce a parameter beta, proportional to the square root of the absolute product of the net charges of monomers, and show that protein complexes characterized with small or very large beta tend to have neutral pH-optimum. Further more, protein complexes made of monomers carrying the same polarity net charge at neutral pH have either very low or very high pH-optimum of binding. These findings are used to propose empirical rule for predicting pH-optimum of binding provided that the amino acid compositions of the corresponding monomers are available.
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Affiliation(s)
- Rooplekha C Mitra
- Physics Department, Computational Biophysics and Bioinformatics, Clemson University, Clemson, South Carolina 29634, USA
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Vetterli L, Brun T, Giovannoni L, Bosco D, Maechler P. Resveratrol potentiates glucose-stimulated insulin secretion in INS-1E beta-cells and human islets through a SIRT1-dependent mechanism. J Biol Chem 2010; 286:6049-60. [PMID: 21163946 DOI: 10.1074/jbc.m110.176842] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Resveratrol, a polyphenol compound, is known for its effects on energy homeostasis. With properties of energy sensors mediating effects of calorie restriction, sirtuins are targets of resveratrol. The mammalian sirtuin homolog SIRT1 is a protein deacetylase playing a role in glucose metabolism and islet function. Here, we investigated the effects of resveratrol and possible link with SIRT1 in β-cells. Insulinoma INS-1E cells and human islets were cultured with resveratrol before analyzing their physiological responses. Treatment of INS-1E cells for 24 h with 25 μM resveratrol resulted in marked potentiation of glucose-stimulated insulin secretion. This effect was associated with elevated glycolytic flux, resulting in increased glucose oxidation, ATP generation, and mitochondrial oxygen consumption. Such changes correlated with up-regulation of key genes for β-cell function, i.e. Glut2, glucokinase, Pdx-1, Hnf-1α, and Tfam. In human islets, chronic resveratrol treatment similarly increased both the glucose secretory response and expression of the same set of genes, eventually restoring the glucose response in islets obtained from one type 2 diabetic donor. Overexpression of Sirt1 in INS-1E cells potentiated resveratrol effects on insulin secretion. Conversely, inhibition of SIRT1 achieved either by expression of an inactive mutant or by using the EX-527 inhibitor, both abolished resveratrol effects on glucose responses. Treatment of INS-1E cells with EX-527 also prevented resveratrol-induced up-regulation of Glut2, glucokinase, Pdx-1, and Tfam. Resveratrol markedly enhanced the glucose response of INS-1E cells and human islets, even after removal of the compound from the medium. These effects were mediated by and fully dependent on active SIRT1, defining a new role for SIRT1 in the regulation of insulin secretion.
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Affiliation(s)
- Laurène Vetterli
- Department of Cell Physiology and Metabolism, University of Geneva Medical Center and Geneva University Hospitals, 1211 Geneva, Switzerland
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Abstract
The pathophysiology of type 2 diabetes mellitus (DM) is varied and complex. However, the association of DM with obesity and inactivity indicates an important, and potentially pathogenic, link between fuel and energy homeostasis and the emergence of metabolic disease. Given the central role for mitochondria in fuel utilization and energy production, disordered mitochondrial function at the cellular level can impact whole-body metabolic homeostasis. Thus, the hypothesis that defective or insufficient mitochondrial function might play a potentially pathogenic role in mediating risk of type 2 DM has emerged in recent years. Here, we summarize current literature on risk factors for diabetes pathogenesis, on the specific role(s) of mitochondria in tissues involved in its pathophysiology, and on evidence pointing to alterations in mitochondrial function in these tissues that could contribute to the development of DM. We also review literature on metabolic phenotypes of existing animal models of impaired mitochondrial function. We conclude that, whereas the association between impaired mitochondrial function and DM is strong, a causal pathogenic relationship remains uncertain. However, we hypothesize that genetically determined and/or inactivity-mediated alterations in mitochondrial oxidative activity may directly impact adaptive responses to overnutrition, causing an imbalance between oxidative activity and nutrient load. This imbalance may lead in turn to chronic accumulation of lipid oxidative metabolites that can mediate insulin resistance and secretory dysfunction. More refined experimental strategies that accurately mimic potential reductions in mitochondrial functional capacity in humans at risk for diabetes will be required to determine the potential pathogenic role in human insulin resistance and type 2 DM.
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Duraisamy P, Elango S, Vishwanandha VP, Balamurugan R. Prevalence of mitochondrial tRNA gene mutations and their association with specific clinical phenotypes in patients with type 2 diabetes mellitus of Coimbatore. Genet Test Mol Biomarkers 2010; 14:49-55. [PMID: 20143911 DOI: 10.1089/gtmb.2009.0024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The association of mitochondrial DNA mutation with type 2 diabetes mellitus (T2DM) is well established. In this study we aimed to assess the frequency of A3243G, A8296G, and other mitochondrial mutations with reference to clinical features in the diabetic population of Coimbatore, India. The study group included 150 patients (89 women and 61 men) with T2DM, whereas the control group included 100 nondiabetic people (59 women and 41 men). Genotyping was done by polymerase chain reaction followed by single-strand confirmation polymorphism method. A3243G and A8296G mutations were found to be prevalent in patients with T2DM when compared with the control group. The A3243G mutation was found in two patients, and both these patients showed similar clinical characteristics, thus representing a putative clinical subtype. A8296G mutation was detected in one patient. The same mutation was shared with his mother who was diagnosed to have diabetes mellitus (DM) with neuromuscular disorder. The siblings of the patient did not show any symptoms of DM. Lipid profile and urea and creatinine levels were found to be significantly high (10% and 0.064%) in patients with T2DM compared with control subjects. We concluded that the identification of these mitochondrial point mutations indicates a new genetic predisposition of DM in Coimbatore population.
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Affiliation(s)
- Pradeepa Duraisamy
- School of Biotechnology and Genetic Engineering, Bharathiar University, Coimbatore, India
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Meas T, Laloi-Michelin M, Virally M, Ambonville C, Kevorkian JP, Guillausseau PJ. Diagnostic clinique et biologique du diabète mitochondrial et particularités de sa prise en charge. Rev Med Interne 2010; 31:216-21. [DOI: 10.1016/j.revmed.2008.11.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Revised: 11/19/2008] [Accepted: 11/26/2008] [Indexed: 10/21/2022]
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McKnight AJ, Currie D, Maxwell AP. Unravelling the genetic basis of renal diseases; from single gene to multifactorial disorders. J Pathol 2010; 220:198-216. [PMID: 19882676 DOI: 10.1002/path.2639] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Chronic kidney disease is common with up to 5% of the adult population reported to have an estimated glomerular filtration rate of < 60 ml/min/1.73 m(2). A large number of pathogenic mutations have been identified that are responsible for 'single gene' renal disorders, such as autosomal dominant polycystic kidney disease and X-linked Alport syndrome. These single gene disorders account for < 15% of the burden of end-stage renal disease that requires dialysis or kidney transplantation. It has proved more difficult to identify the genetic susceptibility underlying common, complex, multifactorial kidney conditions, such as diabetic nephropathy and hypertensive nephrosclerosis. This review describes success to date and explores strategies currently employed in defining the genetic basis for a number of renal disorders. The complementary use of linkage studies, candidate gene and genome-wide association analyses are described and a collation of renal genetic resources highlighted.
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Affiliation(s)
- Amy J McKnight
- Nephrology Research Group, Queen's University of Belfast, Belfast BT9 7AB, Northern Ireland, UK
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