1
|
Rojo M, Pérez H, Millán AL, Pautasso MC, Frechtel GD, Cerrone GE. Relationship of Mitochondrial DNA Oxidation and Content with Metabolic Syndrome and Cardiovascular Risk in Obesity Phenotypes. J Obes 2024; 2024:3008093. [PMID: 39297082 PMCID: PMC11410407 DOI: 10.1155/2024/3008093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 07/04/2024] [Accepted: 07/25/2024] [Indexed: 09/21/2024] Open
Abstract
Objective Obesity, chronic inflammation, and oxidative stress can influence mitochondrial DNA (mtDNA) content. Our objective was to evaluate the oxidation level and content of mtDNA and its relationship with metabolic parameters in metabolically healthy obese (MHO) compared to metabolically unhealthy obese (MUO) and normal weight (NW) controls. Materials and Methods We studied 94 NW, 95 MHO, and 97 MUO individuals between 18 and 80 years old. Relative mtDNA content and mtDNA oxidation level (8-oxoguanine, 8-OxoG) were determined in peripheral blood leukocytes by the SYBR Green method of real-time PCR. One-way ANOVA and Tukey test were used to compare biochemical, clinical, and anthropometric characteristics, as well as mtDNA content and 8-OxoG. Results A progressive decrease in mtDNA content was observed between NW, MHO, and MUO with significant differences in MUO vs. NW (p: 0.04). An increase in 8-OxoG was observed in MUO patients compared to the other groups (MUO vs. MHO p: 0.01; MUO vs. NW p: 0.04). mtDNA content was directly correlated with HDL-c (p < 0.01) and inversely with waist circumference (p: 0.01) and LDL-c (p: 0.05). mtDNA content decreased, and the oxidation level increased concomitantly with the presence of obesity, the number of MS components, higher coronary risk, and insulin resistance parameters. Conclusion MHO presented a similar mtDNA oxidation level to NW and mtDNA content to the MUO, placing the MHO individuals as having an intermediate phenotype. Changes in mtDNA content and oxidation were correlated to the lipid profile related to obesity and/or MS presence, probably associated with oxidative stress and chronic low-grade inflammation.
Collapse
Affiliation(s)
- Mailén Rojo
- Universidad de Buenos Aires Facultad de Farmacia y Bioquímica Departamento de Microbiología, Inmunología, Biotecnología y Genética, Buenos Aires, Argentina
- Universidad de Buenos Aires-CONICET Instituto de Inmunología Genética y Metabolismo (INIGEM), Buenos Aires, Argentina
| | - Hernán Pérez
- Universidad de Buenos Aires-CONICET Instituto de Inmunología Genética y Metabolismo (INIGEM), Buenos Aires, Argentina
- Servicio de Nutrición-Hospital de Clínicas José de San Martin, Buenos Aires, Argentina
| | - Andrea Liliana Millán
- Universidad de Buenos Aires Facultad de Farmacia y Bioquímica Departamento de Microbiología, Inmunología, Biotecnología y Genética, Buenos Aires, Argentina
- Universidad de Buenos Aires-CONICET Instituto de Inmunología Genética y Metabolismo (INIGEM), Buenos Aires, Argentina
| | - María Constanza Pautasso
- Universidad de Buenos Aires-CONICET Instituto de Inmunología Genética y Metabolismo (INIGEM), Buenos Aires, Argentina
| | - Gustavo Daniel Frechtel
- Universidad de Buenos Aires-CONICET Instituto de Inmunología Genética y Metabolismo (INIGEM), Buenos Aires, Argentina
- Servicio de Nutrición-Hospital de Clínicas José de San Martin, Buenos Aires, Argentina
- Fundación Héctor Alejandro (H.A) Barceló Instituto Universitario de Ciencias de la Salud, Buenos Aires, Argentina
| | - Gloria Edith Cerrone
- Universidad de Buenos Aires Facultad de Farmacia y Bioquímica Departamento de Microbiología, Inmunología, Biotecnología y Genética, Buenos Aires, Argentina
- Universidad de Buenos Aires-CONICET Instituto de Inmunología Genética y Metabolismo (INIGEM), Buenos Aires, Argentina
| |
Collapse
|
2
|
Li Y, Zhang Z, Zhang Z, Zheng N, Ding X. Empagliflozin, a sodium-glucose cotransporter inhibitor enhancing mitochondrial action and cardioprotection in metabolic syndrome. J Cell Physiol 2024; 239:e31264. [PMID: 38764242 DOI: 10.1002/jcp.31264] [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: 09/05/2023] [Revised: 03/13/2024] [Accepted: 03/18/2024] [Indexed: 05/21/2024]
Abstract
Metabolic syndrome (MetS) has a large clinical population nowadays, usually due to excessive energy intake and lack of exercise. During MetS, excess nutrients stress the mitochondria, resulting in relative hypoxia in tissues and organs, even when blood supply is not interrupted or reduced, making mitochondrial dysfunction a central pathogenesis of cardiovascular disease in the MetS. Sodium-glucose cotransporter 2 inhibitors were designed as a hyperglycemic drug that acts on the renal tubules to block sugar reabsorption in primary urine. Recently they have been shown to have anti-inflammatory and other protective effects on cardiomyocytes in MetS, and have also been recommended in the latest heart failure guidelines as a routine therapy. Among these inhibitors, empagliflozin shows better clinical promise due to less influence from glomerular filtration rate. This review focuses on the mitochondrial mechanisms of empagliflozin, which underlie the anti-inflammatory and recover cellular functions in MetS cardiomyocytes, including stabilizing calcium concentration, mediating metabolic reprogramming, maintaining homeostasis of mitochondrial quantity and quality, stable mitochondrial DNA copy number, and repairing damaged mitochondrial DNA.
Collapse
Affiliation(s)
- Yunhao Li
- Graduate School, China Medical University, Shenyang, China
- Department of Cardiology, General Hospital of Northern Theater Command, Shenyang, China
| | - Zhanming Zhang
- Faculty of Science, The University of Hong Kong, Hong Kong, China
| | - Zheming Zhang
- Graduate School, China Medical University, Shenyang, China
- Department of Thoracic Surgery, The First Hospital of China Medical University, Shenyang, China
| | - Ningning Zheng
- Department of Pathophysiology, College of Basic Medical Science, China Medical University, Shenyang, China
| | - Xudong Ding
- Department of Anesthesiology, Shengjing Hospital of China Medical University, Shenyang, China
| |
Collapse
|
3
|
Huang C, Chen L, Li J, Ma J, Luo J, Lv Q, Xiao J, Gao P, Chai W, Li X, Zhang M, Hu F, Hu D, Qin P. Mitochondrial DNA Copy Number and Risk of Diabetes Mellitus and Metabolic Syndrome. J Clin Endocrinol Metab 2023; 109:e406-e417. [PMID: 37431585 DOI: 10.1210/clinem/dgad403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 07/04/2023] [Accepted: 07/06/2023] [Indexed: 07/12/2023]
Abstract
CONTEXT Mitochondrial DNA (mtDNA) plays a key role in diabetes mellitus and metabolic syndrome (MetS). An increasing number of studies have reported the association between mtDNA copy number (mtDNA-CN) and the risk of diabetes mellitus and MetS; however, the associations remain conflicted and a systematic review and meta-analysis on the association between mtDNA-CN and diabetes mellitus and MetS is lacking. OBJECTIVE We aimed to investigate the association of mtDNA-CN and diabetes mellitus and MetS using a systematic review and meta-analysis of observational studies. METHODS PubMed, EMBASE, and Web of Science were searched up to December 15, 2022. Random-effect models were used to summarize the relative risks (RRs) and 95% CIs. RESULTS A total of 19 articles were included in the systematic review and 6 articles (12 studies) in the meta-analysis involving 21 714 patients with diabetes (318 870 participants) and 5031 MetS (15 040 participants). Compared to the highest mtDNA-CN, the summary RR (95% CIs) for the lowest mtDNA-CN were 1.06 (95% CI, 1.01-1.12; I2 = 79.4%; n = 8) for diabetes (prospective study: 1.11 (1.02-1.21); I2 = 22.6%; n = 4; case-control: 1.27 (0.66-2.43); I2 = 81.8%; n = 2; cross-sectional: 1.01 (0.99-1.03); I2 = 74.7%; n = 2), and 1.03 (0.99-1.07; I2 = 70.6%; n = 4) for MetS (prospective: 2.87 (1.51-5.48); I2 = 0; n = 2; cross-sectional: 1.02 (1.01-1.04); I2 = 0; n = 2). CONCLUSION Decreased mtDNA-CN was associated with increased risk of diabetes mellitus and MetS when limited to prospective studies. More longitudinal studies are warranted.
Collapse
Affiliation(s)
- Cuihong Huang
- Center for Clinical Epidemiology and Evidence-based Medicine, Shenzhen Qianhai Shekou Free Trade Zone Hospital, Shenzhen, 518000, Guangdong, China
- School of Public Health, Sun Yat-Sen University, Guangzhou, 510080, Guangdong, China
| | - Lifang Chen
- Department of Cardiovascular Medicine, Shenzhen Qianhai Shekou Free Trade Zone Hospital, Shenzhen, 518000, Guangdong, China
| | - Jiangtao Li
- Department of Cardiovascular Medicine, Shenzhen Qianhai Shekou Free Trade Zone Hospital, Shenzhen, 518000, Guangdong, China
| | - Juanjuan Ma
- Center for Clinical Epidemiology and Evidence-based Medicine, Shenzhen Qianhai Shekou Free Trade Zone Hospital, Shenzhen, 518000, Guangdong, China
| | - Jun Luo
- Department of Cardiovascular Medicine, Shenzhen Qianhai Shekou Free Trade Zone Hospital, Shenzhen, 518000, Guangdong, China
| | - Qian Lv
- Department of Cardiovascular Medicine, Shenzhen Qianhai Shekou Free Trade Zone Hospital, Shenzhen, 518000, Guangdong, China
| | - Jian Xiao
- Department of Cardiovascular Medicine, Shenzhen Qianhai Shekou Free Trade Zone Hospital, Shenzhen, 518000, Guangdong, China
| | - Pan Gao
- Department of Neurology, Shenzhen University General Hospital, Shenzhen, 518000, Guangdong, China
| | - Wen Chai
- Department of Neurology, Shenzhen University General Hospital, Shenzhen, 518000, Guangdong, China
| | - Xu Li
- Department of Neurosurgery, The Second Affiliated Hospital of Shenzhen University, Shenzhen, 518000, Guangdong, China
| | - Ming Zhang
- Department of Biostatistics and Epidemiology, School of Public Health, Shenzhen University Health Science Center, Shenzhen, 518000, Guangdong, China
| | - Fulan Hu
- Department of Biostatistics and Epidemiology, School of Public Health, Shenzhen University Health Science Center, Shenzhen, 518000, Guangdong, China
| | - Dongsheng Hu
- Department of Biostatistics and Epidemiology, School of Public Health, Shenzhen University Health Science Center, Shenzhen, 518000, Guangdong, China
| | - Pei Qin
- Center for Clinical Epidemiology and Evidence-based Medicine, Shenzhen Qianhai Shekou Free Trade Zone Hospital, Shenzhen, 518000, Guangdong, China
| |
Collapse
|
4
|
Paolini E, Longo M, Corsini A, Dongiovanni P. The Non-Invasive Assessment of Circulating D-Loop and mt-ccf Levels Opens an Intriguing Spyhole into Novel Approaches for the Tricky Diagnosis of NASH. Int J Mol Sci 2023; 24:ijms24032331. [PMID: 36768654 PMCID: PMC9916898 DOI: 10.3390/ijms24032331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 01/26/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the commonest liver disease worldwide affecting both adults and children. Nowadays, no therapeutic strategies have been approved for NAFLD management, and hepatic biopsy remains the gold standard procedure for its diagnosis. NAFLD is a multifactorial disease whose pathogenesis is affected by environmental and genetic factors, and it covers a spectrum of conditions ranging from simple steatosis up to nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Several studies underlined the urgent need to develop an NAFLD risk prediction model based on genetics, biochemical indicators, and metabolic disorders. The loss of mitochondrial dynamics represents a typical feature of progressive NAFLD. The imbalance of mitochondrial lifecycle together with the impairment of mitochondrial biomass and function trigger oxidative stress, which in turn damages mitochondrial DNA (mtDNA). We recently demonstrated that the main genetic predictors of NAFLD led to mitochondrial dysfunction. Moreover, emerging evidence shows that variations in the displacement loop (D-loop) region impair mtDNA replication, and they have been associated with advanced NAFLD. Finally, lower levels of mitophagy foster the overload of damaged mitochondria, resulting in the release of cell-free circulating mitochondrial DNA (mt-ccf) that exacerbates liver injury. Thus, in this review we summarized what is known about D-loop region alterations and mt-ccf content during NAFLD to propose them as novel non-invasive biomarkers.
Collapse
Affiliation(s)
- Erika Paolini
- General Medicine and Metabolic Diseases, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20133 Milano, Italy
| | - Miriam Longo
- General Medicine and Metabolic Diseases, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
- Department of Clinical Sciences and Community Health, Università degli Studi di Milano, 20122 Milano, Italy
| | - Alberto Corsini
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20133 Milano, Italy
- IRCCS Multimedica, 20099 Milan, Italy
| | - Paola Dongiovanni
- General Medicine and Metabolic Diseases, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
- Correspondence: ; Tel.: +39-02-5503-3467; Fax: +39-02-5032-0296
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
Sundquist K, Sundquist J, Wang X, Palmer K, Memon AA. Baseline mitochondrial DNA copy number and heart failure incidence and its role in overall and heart failure mortality in middle-aged women. Front Cardiovasc Med 2022; 9:1012403. [PMID: 36440036 PMCID: PMC9685522 DOI: 10.3389/fcvm.2022.1012403] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 10/24/2022] [Indexed: 01/12/2024] Open
Abstract
Heart failure (HF) is a leading cause of death in both men and women. However, risk factors seem to differ for men and women and significant gaps in sex-specific knowledge exist. Mitochondria are critical for cardiomyocytes and in this study, we investigated the role of baseline mitochondrial DNA copy number (mtDNA-CN) in HF incidence in middle-aged women and its possible role in the association between myocardial infarction (MI) and HF. Finally, we also investigated whether baseline mtDNA-CN was associated with overall and HF mortality. Baseline levels of mtDNA-CN were quantified by droplet digital PCR in a population-based follow-up study of middle-aged (50-59 years) Swedish women (n = 2,508). The median follow-up period was 17 years. Levels of mtDNA-CN were associated with age, BMI, alcohol, smoking, education, physical activity and lipid biomarkers. Multivariable Cox regression analysis adjusted for potential confounders showed that each standard deviation decrease of baseline mtDNA-CN was associated with higher incidence of HF (HR = 1.34; 95% CI=1.11-1.63). Similar results were obtained when mtDNA-CN levels were categorized into quartiles with lowest vs. highest quartile showing the highest risk of HF incidence (HR = 2.04 95% CI=1.14; 3.63). We could not detect any role of mtDNA-CN in the association between MI and HF incidence. Lower baseline mtDNA-CN levels were associated with both overall (HR = 1.27; 95% CI=1.10-1.46) and HF mortality (HR = 1.93; 95% CI=1.04-3.60); however, in multivariable analysis adjusted for potential confounders, the higher risks of HF mortality were no longer significant (HR=1.57; 95% CI=0.85-2.90). In conclusion, low baseline mtDNA-CN is an easily quantifiable molecular risk factor for HF incidence and may be a risk factor for overall and HF-related mortality.
Collapse
Affiliation(s)
| | | | | | | | - Ashfaque A. Memon
- Center for Primary Health Care Research, Lund University/Region Skåne, Malmö, Sweden
| |
Collapse
|
7
|
Saha D, Mehndiratta M, Aaradhana, Shah D, Gupta P. Oxidative Stress, Mitochondrial Dysfunction, and Premature Ageing in Severe Acute Malnutrition in Under-Five Children. Indian J Pediatr 2022; 89:558-562. [PMID: 35044618 DOI: 10.1007/s12098-021-03981-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 08/31/2021] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To assess oxidative stress, mitochondrial dysfunction, and premature ageing in children with severe acute malnutrition (SAM). METHODS This cross-sectional study was conducted in children (1 mo-5 y) with SAM (defined as per WHO criteria) presenting to Pediatrics inpatient department. Oxidative stress, mitochondrial dysfunction, and premature ageing were assessed by measuring and comparing total antioxidant status (TAOS), mitochondrial DNA (mtDNA) content, and telomere length (TL), respectively in 40 under-five children with SAM and 40 age- and sex-matched non-malnourished controls. RESULTS Oxidative stress was significantly increased in children with SAM, reflected by lower median (IQR) TAOS in cases as compared to controls [10.78 (9.08, 12.3) vs. 16.63 (15.20, 18.03) mM Trolox, p < 0.001]. Median (IQR) mtDNA content was significantly increased in children with SAM [188.7 (105.2, 398.9) vs. 116.2 (67.2, 154.6), p < 0.001]. There was no significant difference in telomere length between cases and controls [1184.5 (894, 1408) vs.1082.6 (823.3, 1479), p = 0.747]. CONCLUSION Children with SAM had significantly increased oxidative stress that possibly caused mitochondrial dysfunction but no premature ageing.
Collapse
Affiliation(s)
- Dipanwita Saha
- Department of Pediatrics, University College of Medical Sciences and Guru Teg Bahadur Hospital, Delhi, 110095, India
| | - Mohit Mehndiratta
- Department of Biochemistry, University College of Medical Sciences and Guru Teg Bahadur Hospital, Delhi, India
| | - Aaradhana
- Department of Pediatrics, University College of Medical Sciences and Guru Teg Bahadur Hospital, Delhi, 110095, India
| | - Dheeraj Shah
- Department of Pediatrics, University College of Medical Sciences and Guru Teg Bahadur Hospital, Delhi, 110095, India
| | - Piyush Gupta
- Department of Pediatrics, University College of Medical Sciences and Guru Teg Bahadur Hospital, Delhi, 110095, India.
| |
Collapse
|
8
|
Chung JK, Ahn YM, Kim SA, Joo EJ. Differences in mitochondrial DNA copy number between patients with bipolar I and II disorders. J Psychiatr Res 2022; 145:325-333. [PMID: 33190840 DOI: 10.1016/j.jpsychires.2020.11.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 10/08/2020] [Accepted: 11/05/2020] [Indexed: 02/01/2023]
Abstract
Mitochondria play a critical role in energy metabolism. Genetic, postmortem brain, and brain imaging studies of bipolar disorder (BD) patients indicated that mitochondrial dysfunction might explain BD pathophysiology. Mitochondrial function can be indirectly evaluated by measuring mitochondrial DNA (mtDNA) copy numbers. We recruited 186 bipolar I disorder (BD1) and 95 bipolar II disorder (BD2) patients, and age- and sex-matched controls. MtDNA copy numbers in peripheral blood cells were measured via quantitative polymerase chain reaction. We explored parameters (including age and clinical features) that might affect mtDNA copy numbers. We found that BD1 patients had a lower mtDNA copy number than controls and that mtDNA copy number was negatively associated with the number of mood episodes. BD2 patients had a higher mtDNA copy number than controls. Thus, changes in mitochondrial function may influence BD pathophysiology. The opposite directions of the association with mtDNA copy number in BD1 and BD2 patients suggests that the difference in pathophysiology may be associated with mitochondrial function.
Collapse
Affiliation(s)
- Jae Kyung Chung
- Department of Psychiatry, Eumsung-somang Hospital, Eumsung, Republic of Korea
| | - Yong Min Ahn
- Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea; Department of Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea; Institute of Human Behavioral Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea
| | - Soon Ae Kim
- Department of Pharmacology, School of Medicine, Eulji University, Daejeon, Republic of Korea.
| | - Eun-Jeong Joo
- Department of Neuropsychiatry, School of Medicine, Eulji University, Daejeon, Republic of Korea; Department of Psychiatry, Nowon Eulji Medical Center, Eulji University, Seoul, Republic of Korea.
| |
Collapse
|
9
|
Agius R, Pace NP, Fava S. Reduced leukocyte mitochondrial copy number in metabolic syndrome and metabolically healthy obesity. Front Endocrinol (Lausanne) 2022; 13:886957. [PMID: 35957819 PMCID: PMC9357898 DOI: 10.3389/fendo.2022.886957] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 06/29/2022] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE This study aimed to investigate the associations between peripheral blood leukocyte mitochondrial copy number, metabolic syndrome, and adiposity-related body composition phenotypes in a high prevalence population. METHODS A single center cross-sectional study was conducted, consisting of 521 middle-aged subjects of Maltese-Caucasian ethnicity. Participants were stratified according to the presence of metabolic syndrome and different metabolic health definitions based on NCEP-ATP III criteria. Relative leukocyte mitochondrial DNA copy number was determined by quantitative polymerase chain reaction and corrected for leukocyte and platelet count. The associations between mitochondrial copy number and metabolic syndrome components was evaluated and adjusted for age and gender. RESULTS Significant negative correlations between mtDNA copy number and BMI, waist circumference, triglyceride levels, fasting plasma glucose, HbA1c, HOMA-IR and hsCRP were observed, along with a positive correlation with HDL-C levels. Mitochondrial copy number was lower in individuals with metabolic syndrome. When compared to metabolically healthy normal weight subjects, a reduction in mtDNA copy number was observed in both the metabolically healthy and unhealthy obese categories. CONCLUSION Our data supports the association between reduced leukocyte mtDNA copy number, obesity, and metabolic syndrome. This investigation expands on the spectrum of associations between mtDNA copy number and metabolic phenotypes in different populations and underpins the role of mitochondrial dysfunction in the development and progression of metabolic syndrome and its components.
Collapse
Affiliation(s)
- Rachel Agius
- Faculty of Medicine and Surgery, University of Malta, Msida, Malta
- Department of Medicine, Mater Dei Hospital, Msida, Malta
| | - Nikolai Paul Pace
- Faculty of Medicine and Surgery, University of Malta, Msida, Malta
- Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
- *Correspondence: Nikolai Paul Pace,
| | - Stephen Fava
- Faculty of Medicine and Surgery, University of Malta, Msida, Malta
- Department of Medicine, Mater Dei Hospital, Msida, Malta
| |
Collapse
|
10
|
Fazzini F, Lamina C, Raftopoulou A, Koller A, Fuchsberger C, Pattaro C, Del Greco FM, Döttelmayer P, Fendt L, Fritz J, Meiselbach H, Schönherr S, Forer L, Weissensteiner H, Pramstaller PP, Eckardt K, Hicks AA, Kronenberg F. Association of mitochondrial DNA copy number with metabolic syndrome and type 2 diabetes in 14 176 individuals. J Intern Med 2021; 290:190-202. [PMID: 33453124 PMCID: PMC8359248 DOI: 10.1111/joim.13242] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 11/24/2020] [Accepted: 12/14/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND Mitochondria play an important role in cellular metabolism, and their dysfunction is postulated to be involved in metabolic disturbances. Mitochondrial DNA is present in multiple copies per cell. The quantification of mitochondrial DNA copy number (mtDNA-CN) might be used to assess mitochondrial dysfunction. OBJECTIVES We aimed to investigate the cross-sectional association of mtDNA-CN with type 2 diabetes and the potential mediating role of metabolic syndrome. METHODS We examined 4812 patients from the German Chronic Kidney Disease (GCKD) study and 9364 individuals from the Cooperative Health Research in South Tyrol (CHRIS) study. MtDNA-CN was measured in whole blood using a plasmid-normalized qPCR-based assay. RESULTS In both studies, mtDNA-CN showed a significant correlation with most metabolic syndrome parameters: mtDNA-CN decreased with increasing number of metabolic syndrome components. Furthermore, individuals with low mtDNA-CN had significantly higher odds of metabolic syndrome (OR = 1.025; 95% CI = 1.011-1.039, P = 3.19 × 10-4 , for each decrease of 10 mtDNA copies) and type 2 diabetes (OR = 1.027; 95% CI = 1.012-1.041; P = 2.84 × 10-4 ) in a model adjusted for age, sex, smoking and kidney function in the meta-analysis of both studies. Mediation analysis revealed that the association of mtDNA-CN with type 2 diabetes was mainly mediated by waist circumference in the GCKD study (66%) and by several metabolic syndrome parameters, especially body mass index and triglycerides, in the CHRIS study (41%). CONCLUSIONS Our data show an inverse association of mtDNA-CN with higher risk of metabolic syndrome and type 2 diabetes. A major part of the total effect of mtDNA-CN on type 2 diabetes is mediated by obesity parameters.
Collapse
Affiliation(s)
- F. Fazzini
- From theDepartment of Genetics and PharmacologyInstitute of Genetic EpidemiologyMedical University of InnsbruckInnsbruckAustria
| | - C. Lamina
- From theDepartment of Genetics and PharmacologyInstitute of Genetic EpidemiologyMedical University of InnsbruckInnsbruckAustria
| | - A. Raftopoulou
- Eurac ResearchInstitute for BiomedicineAffiliated Institute of the University of LübeckBolzanoItaly
| | - A. Koller
- From theDepartment of Genetics and PharmacologyInstitute of Genetic EpidemiologyMedical University of InnsbruckInnsbruckAustria
| | - C. Fuchsberger
- Eurac ResearchInstitute for BiomedicineAffiliated Institute of the University of LübeckBolzanoItaly
| | - C. Pattaro
- Eurac ResearchInstitute for BiomedicineAffiliated Institute of the University of LübeckBolzanoItaly
| | - F. M. Del Greco
- Eurac ResearchInstitute for BiomedicineAffiliated Institute of the University of LübeckBolzanoItaly
| | - P. Döttelmayer
- From theDepartment of Genetics and PharmacologyInstitute of Genetic EpidemiologyMedical University of InnsbruckInnsbruckAustria
| | - L. Fendt
- From theDepartment of Genetics and PharmacologyInstitute of Genetic EpidemiologyMedical University of InnsbruckInnsbruckAustria
| | - J. Fritz
- Department of Medical StatisticsInformatics and Health EconomicsMedical University of InnsbruckInnsbruckAustria
- Department of Integrative PhysiologyUniversity of Colorado BoulderBoulderCOUSA
| | - H. Meiselbach
- Department of Nephrology and HypertensionFriedrich‐Alexander Universität Erlangen‐Nürnberg (FAU)ErlangenGermany
| | - S. Schönherr
- From theDepartment of Genetics and PharmacologyInstitute of Genetic EpidemiologyMedical University of InnsbruckInnsbruckAustria
| | - L. Forer
- From theDepartment of Genetics and PharmacologyInstitute of Genetic EpidemiologyMedical University of InnsbruckInnsbruckAustria
| | - H. Weissensteiner
- From theDepartment of Genetics and PharmacologyInstitute of Genetic EpidemiologyMedical University of InnsbruckInnsbruckAustria
| | - P. P. Pramstaller
- Eurac ResearchInstitute for BiomedicineAffiliated Institute of the University of LübeckBolzanoItaly
| | - K.‐U. Eckardt
- Department of Nephrology and HypertensionFriedrich‐Alexander Universität Erlangen‐Nürnberg (FAU)ErlangenGermany
- Department of Nephrology and Medical Intensive CareCharité – Universitätsmedizin BerlinBerlinGermany
| | - A. A. Hicks
- Eurac ResearchInstitute for BiomedicineAffiliated Institute of the University of LübeckBolzanoItaly
| | - F. Kronenberg
- From theDepartment of Genetics and PharmacologyInstitute of Genetic EpidemiologyMedical University of InnsbruckInnsbruckAustria
| | | |
Collapse
|
11
|
Ganel L, Chen L, Christ R, Vangipurapu J, Young E, Das I, Kanchi K, Larson D, Regier A, Abel H, Kang CJ, Scott A, Havulinna A, Chiang CWK, Service S, Freimer N, Palotie A, Ripatti S, Kuusisto J, Boehnke M, Laakso M, Locke A, Stitziel NO, Hall IM. Mitochondrial genome copy number measured by DNA sequencing in human blood is strongly associated with metabolic traits via cell-type composition differences. Hum Genomics 2021; 15:34. [PMID: 34099068 PMCID: PMC8185936 DOI: 10.1186/s40246-021-00335-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 05/26/2021] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Mitochondrial genome copy number (MT-CN) varies among humans and across tissues and is highly heritable, but its causes and consequences are not well understood. When measured by bulk DNA sequencing in blood, MT-CN may reflect a combination of the number of mitochondria per cell and cell-type composition. Here, we studied MT-CN variation in blood-derived DNA from 19184 Finnish individuals using a combination of genome (N = 4163) and exome sequencing (N = 19034) data as well as imputed genotypes (N = 17718). RESULTS We identified two loci significantly associated with MT-CN variation: a common variant at the MYB-HBS1L locus (P = 1.6 × 10-8), which has previously been associated with numerous hematological parameters; and a burden of rare variants in the TMBIM1 gene (P = 3.0 × 10-8), which has been reported to protect against non-alcoholic fatty liver disease. We also found that MT-CN is strongly associated with insulin levels (P = 2.0 × 10-21) and other metabolic syndrome (metS)-related traits. Using a Mendelian randomization framework, we show evidence that MT-CN measured in blood is causally related to insulin levels. We then applied an MT-CN polygenic risk score (PRS) derived from Finnish data to the UK Biobank, where the association between the PRS and metS traits was replicated. Adjusting for cell counts largely eliminated these signals, suggesting that MT-CN affects metS via cell-type composition. CONCLUSION These results suggest that measurements of MT-CN in blood-derived DNA partially reflect differences in cell-type composition and that these differences are causally linked to insulin and related traits.
Collapse
Affiliation(s)
- Liron Ganel
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, USA
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Lei Chen
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, USA
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Ryan Christ
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, USA
| | - Jagadish Vangipurapu
- Institute of Clinical Medicine, Internal Medicine, University of Eastern Finland, Kuopio, Finland
| | - Erica Young
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, USA
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO, USA
| | - Indraniel Das
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, USA
| | - Krishna Kanchi
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, USA
| | - David Larson
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, USA
- Department of Genetics, Washington University School of Medicine, St. Louis, MO, USA
| | - Allison Regier
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, USA
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Haley Abel
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, USA
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Department of Genetics, Washington University School of Medicine, St. Louis, MO, USA
| | - Chul Joo Kang
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, USA
| | - Alexandra Scott
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, USA
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Aki Havulinna
- Institute for Molecular Medicine Finland (FIMM), HiLIFE, University of Helsinki, Helsinki, Finland
- Finnish Institute for Health and Welfare (THL), Helsinki, Finland
| | - Charleston W K Chiang
- Center for Genetic Epidemiology, Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Quantitative and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Susan Service
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA, USA
| | - Nelson Freimer
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA, USA
| | - Aarno Palotie
- Institute for Molecular Medicine Finland (FIMM), HiLIFE, University of Helsinki, Helsinki, Finland
- Analytical and Translational Genetics Unit (ATGU), Psychiatric & Neurodevelopmental Genetics Unit, Departments of Psychiatry and Neurology, Massachusetts General Hospital, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Samuli Ripatti
- Institute for Molecular Medicine Finland (FIMM), HiLIFE, University of Helsinki, Helsinki, Finland
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Johanna Kuusisto
- Institute of Clinical Medicine, Internal Medicine, University of Eastern Finland, Kuopio, Finland
- Department of Medicine, Kuopio University Hospital, Kuopio, Finland
| | - Michael Boehnke
- Department of Biostatistics and Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - Markku Laakso
- Institute of Clinical Medicine, Internal Medicine, University of Eastern Finland, Kuopio, Finland
- Department of Medicine, Kuopio University Hospital, Kuopio, Finland
| | - Adam Locke
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, USA
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Nathan O Stitziel
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, USA.
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO, USA.
- Department of Genetics, Washington University School of Medicine, St. Louis, MO, USA.
| | - Ira M Hall
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, USA.
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA.
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA.
| |
Collapse
|
12
|
Association of mitochondrial DNA copy number with prevalent and incident type 2 diabetes in women: A population-based follow-up study. Sci Rep 2021; 11:4608. [PMID: 33633270 PMCID: PMC7907271 DOI: 10.1038/s41598-021-84132-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 01/29/2021] [Indexed: 02/06/2023] Open
Abstract
Mitochondrial dysfunction is an important factor of the aging process and may play a key role in various diseases. Mitochondrial DNA copy number (mtDNA-CN) is an indirect measure of mitochondrial dysfunction and is associated with type 2 diabetes mellitus (T2DM); however, whether mtDNA-CN can predict the risk of developing T2DM is not well-known. We quantified absolute mtDNA-CN in both prevalent and incident T2DM by well-optimized droplet digital PCR (ddPCR) method in a population-based follow-up study of middle aged (50-59 years) Swedish women (n = 2387). The median follow-up period was 17 years. Compared to those who were free of T2DM, mtDNA-CN was significantly lower in both prevalent T2DM and in women who developed T2DM during the follow-up period. Mitochondrial DNA-copy number was also associated with glucose intolerance, systolic blood pressure, smoking status and education. In multivariable Cox regression analysis, lower baseline mtDNA-CN was prospectively associated with a higher risk of T2DM, independent of age, BMI, education, smoking status and physical activity. Moreover, interaction term analysis showed that smoking increased the effect of low mtDNA-CN at baseline on the risk of incident T2DM. Mitochondrial DNA-copy number may be a risk factor of T2DM in women. The clinical usefulness of mtDNA-CN to predict the future risk of T2DM warrants further investigation.
Collapse
|
13
|
Alam MR, Kim DK. Alterations in telomere length and mitochondrial DNA copy number in human lymphocytes on short-term exposure to moderate hypoxia. Toxicol Rep 2020; 7:1443-1447. [PMID: 33163366 PMCID: PMC7600389 DOI: 10.1016/j.toxrep.2020.10.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 10/11/2020] [Accepted: 10/13/2020] [Indexed: 12/19/2022] Open
Abstract
Exposure to moderate hypoxia for 24 h significantly increased telomere length. Telomere elongation is related to the duration of hypoxia exposure. Mitochondrial DNA copy number was unaffected by hypoxia exposure. Mitochondrial DNA copy number is a more stable marker than telomere length alteration under hypoxia.
Hypoxia is related to a variety of diseases, such as cardiovascular and inflammatory diseases and various cancers. Telomere length (TL) may vary according to the hypoxia level and cell types. To the best of our knowledge, no study has investigated the effect of moderate hypoxia on TL and mitochondrial DNA copy number (mtDNAcn) in human lymphocytes. Therefore, in this study, we analyzed the effect of moderate hypoxia on TL in correlation with mtDNAcn. This study included 32 healthy male nonsmoker’s subjects; in this cohort, we had previously studied sister chromatid exchange and microsatellite instability. Blood samples from each subject were divided into three groups: a control group and two experimental groups exposed to moderate hypoxia for 12 or 24 h. Relative TL and mtDNAcn were measured by a quantitative real-time polymerase chain reaction. The TL in the control group did not significantly differ from that in the experimental group subjected to hypoxia for 12 h; however, the TL in the 24 h hypoxia–treated experimental group was significantly higher than that in the control group. The correlation between TL and mtDNAcn was not statistically significant in the two hypoxic states. The increase in TL was observed on exposure to hypoxia for 24 h and not for 12 h; thus, the findings suggest that telomere elongation is related to hypoxia exposure duration. The mtDNAcn in the two experimental groups did not significantly differ from that in the control group. These observations suggest that mtDNAcn alterations show more genetic stability than TL alterations. To the best of our knowledge, this is the first in vitro study on human lymphocytes reporting an increase in TL and no alteration in mtDNAcn after short-time exposure to moderate hypoxia.
Collapse
Affiliation(s)
- Mohammad Rizwan Alam
- Department of Medical Genetics, School of Medicine, Keimyung University, Daegu, Republic of Korea
| | - Dae-Kwang Kim
- Department of Medical Genetics, School of Medicine, Keimyung University, Daegu, Republic of Korea.,Hanvit Institute for Medical Genetics, Daegu, Republic of Korea
| |
Collapse
|
14
|
Relationship between Decreased Serum Superoxide Dismutase Activity and Metabolic Syndrome: Synergistic Mediating Role of Insulin Resistance and β-Cell Dysfunction. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:5384909. [PMID: 32617139 PMCID: PMC7306846 DOI: 10.1155/2020/5384909] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 05/17/2020] [Accepted: 05/29/2020] [Indexed: 12/12/2022]
Abstract
The interplays of cellular aging and oxidative stress (OS) markers form a complex network, which has been reported to be interrelated with numerous age-related and metabolic diseases, including metabolic syndrome (MS). However, given the multifactorial mechanisms of MS, several important confounders such as dietary factors and the reciprocal effect among these markers have not been considered and adjusted in previous investigations regarding the associations of cellular aging and OS markers with MS and its related metabolic abnormalities. To explicate this, we conducted a cross-sectional study among 533 Chinese adults. All the participants underwent a 75 g oral glucose tolerance test. Dietary data were collected via a 24-hour dietary recall and subsequently analyzed by a registered dietitian using nutrition calculation software. Clinical diagnosis of MS was made according to the revised National Cholesterol Education Program Adult Treatment Panel III criteria (2004) with waist circumference cutoff modified for an Asian population. The leukocyte telomere length, mitochondrial DNA copy number, 8-hydroxy-2-deoxyguanosine, superoxide dismutase (SOD) activity, and glutathione reductase were examined. SOD activity was significantly decreased in MS subjects (62.06 ± 16.89 U/mL vs. 56.25 ± 22.61 U/mL, P = 0.001) and exhibited a descending trend across sequential increase of MS component number (P for trend = 0.031). SOD activity is modestly correlated with glucose indicators and insulin sensitivity and β-cell function indices and was independently and negatively correlated with the level of triglyceride. An independent association between SOD activity and MS was observed after adjusting for metabolic indicators, dietary factors, cellular aging, and OS markers, as well as insulin sensitivity and β-cell function indices. However, the statistical significance of the association between SOD activity and MS was attenuated after adjusting for the Matsuda insulin sensitivity index (ISIM) and insulin secretion-sensitivity index-2 (ISSI-2), suggesting a possible mediating effect. Therefore, we conducted a mediation model analysis, which showed that decreased ISIM and ISSI-2 partially and synergistically mediated the contribution of decreased SOD activity to MS. In conclusion, decreased SOD activity is an independent predictor for increased risk of MS, and insulin resistance and β-cell dysfunction partially mediate the relationship between decreased SOD activity and MS.
Collapse
|
15
|
Shim HB, Arshad O, Gadawska I, Côté HCF, Hsieh AYY. Platelet mtDNA content and leukocyte count influence whole blood mtDNA content. Mitochondrion 2020; 52:108-114. [PMID: 32156645 DOI: 10.1016/j.mito.2020.03.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 02/28/2020] [Accepted: 03/04/2020] [Indexed: 02/06/2023]
Abstract
Changes in whole blood (WB) mitochondrial DNA (mtDNA) content are associated with health and disease. Platelet-derived mtDNA can confound WB mtDNA content measurements. From a sample of 44 volunteers, we show that platelet mtDNA content and platelet:leukocyte ratio are both dependent predictors of WB mtDNA content, but that platelet count itself is not. Furthermore, when platelet:leukocyte ratio increased by <2-fold ex vivo, the effect on WB mtDNA content was minimal. Altogether, this study clarifies the contribution of platelet mtDNA content rather than platelet count on WB mtDNA content measurements, and identifies defined parameters for future research on WB mtDNA content.
Collapse
Affiliation(s)
- Hanjoo B Shim
- Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall #4302, Vancouver, British Columbia, Canada
| | - Omair Arshad
- Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall #4302, Vancouver, British Columbia, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
| | - Izabella Gadawska
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
| | - Hélène C F Côté
- Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall #4302, Vancouver, British Columbia, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Women's Health Research Institute, Vancouver, British Columbia, Canada.
| | - Anthony Y Y Hsieh
- Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall #4302, Vancouver, British Columbia, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
| |
Collapse
|
16
|
Empagliflozin Protects HK-2 Cells from High Glucose-Mediated Injuries via a Mitochondrial Mechanism. Cells 2019; 8:cells8091085. [PMID: 31540085 PMCID: PMC6770192 DOI: 10.3390/cells8091085] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 09/08/2019] [Accepted: 09/13/2019] [Indexed: 02/06/2023] Open
Abstract
Empagliflozin is known to retard the progression of kidney disease in diabetic patients. However, the underlying mechanism is incompletely understood. High glucose induces oxidative stress in renal tubules, eventually leading to mitochondrial damage. Here, we investigated whether empagliflozin exhibits protective functions in renal tubules via a mitochondrial mechanism. We used human proximal tubular cell (PTC) line HK-2 and employed western blotting, terminal deoxynucleotidyl transferase dUTP nick end labelling assay, fluorescence staining, flow cytometry, and enzyme-linked immunosorbent assay to investigate the impact of high glucose and empagliflozin on cellular apoptosis, mitochondrial morphology, and functions including mitochondrial membrane potential (MMP), reactive oxygen species (ROS) production, and adenosine triphosphate (ATP) generation. We found that PTCs were susceptible to high glucose-induced mitochondrial fragmentation, and empagliflozin ameliorated this effect via the regulation of mitochondrial fission (FIS1 and DRP1) and fusion (MFN1 and MFN2) proteins. Empagliflozin reduced the high glucose-induced cellular apoptosis and improved mitochondrial functions by restoring mitochondrial ROS production, MMP, and ATP generation. Our results suggest that empagliflozin may protect renal PTCs from high glucose-mediated injuries through a mitochondrial mechanism. This could be one of the novel mechanisms explaining the benefits demonstrated in EMPA-REG OUTCOME trial.
Collapse
|
17
|
Liu B, Song L, Zhang L, Wu M, Wang L, Cao Z, Zhang B, Xu S, Wang Y. Prenatal aluminum exposure is associated with increased newborn mitochondrial DNA copy number. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 252:330-335. [PMID: 31158661 DOI: 10.1016/j.envpol.2019.05.116] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 02/15/2019] [Accepted: 05/22/2019] [Indexed: 05/15/2023]
Abstract
Aluminum is a widely distributed metal that has been reported to have embryotoxicity and fetotoxicity in animal studies. However, there has been no study of the association between prenatal aluminum exposure and newborn mitochondrial DNA copy number (mtDNAcn). We aimed to investigate the effect of prenatal aluminum exposure on newborn mtDNAcn. A total of 762 mother-newborn pairs were recruited between November 2013 and March 2015 in Wuhan city, China. We measured maternal urinary aluminum concentrations at three trimesters of pregnancy. Relative mtDNAcn was measured in DNA extracted from umbilical cord blood samples. We used generalized estimating equations to assess the relationship between prenatal aluminum exposure and newborn mtDNAcn. The geometric means of creatinine corrected aluminum concentrations were 31.0 μg/g Cr (95% CI: 27.6, 34.7), 40.9 μg/g Cr (95% CI: 35.7, 46.8) and 58.4 μg/g Cr (95% CI: 51.2, 67.4) for the first, second and third trimesters, respectively. After adjustment for potential confounding factors, a doubling of maternal urinary aluminum concentrations during the second and third trimesters was related to 3.16% (95% CI: 0.88, 5.49) and 4.20% (95% CI: 1.64, 6.81) increases in newborn mtDNAcn, respectively, while the association between maternal urinary aluminum concentration during the first trimester and newborn mtDNAcn was not significant (percent difference: 0.70%, 95% CI: -2.25, 3.73). Prenatal aluminum exposure during the second and third trimesters was positively associated with newborn mtDNAcn. Further studies are essential to elucidate on the potential health consequences of newborn mtDNAcn.
Collapse
Affiliation(s)
- Bingqing Liu
- Department of Maternal and Child Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, 430030, Hubei, Wuhan, China
| | - Lulu Song
- Department of Maternal and Child Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, 430030, Hubei, Wuhan, China
| | - Lina Zhang
- Department of Maternal and Child Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, 430030, Hubei, Wuhan, China
| | - Mingyang Wu
- Department of Maternal and Child Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, 430030, Hubei, Wuhan, China
| | - Lulin Wang
- Department of Maternal and Child Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, 430030, Hubei, Wuhan, China
| | - Zhongqiang Cao
- Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, Hongkong Road 100, 430030, Hubei, Wuhan, China
| | - Bin Zhang
- Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, Hongkong Road 100, 430030, Hubei, Wuhan, China
| | - Shunqing Xu
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Youjie Wang
- Department of Maternal and Child Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, 430030, Hubei, Wuhan, China.
| |
Collapse
|
18
|
Santos JL, Cataldo LR, Cortés-Rivera C, Bravo C, Díaz-Casanova L, Martínez JA, Milagro FI, Galgani J. Plasma lactate and leukocyte mitochondrial DNA copy number as biomarkers of insulin sensitivity in non-diabetic women. J Physiol Biochem 2019; 75:285-297. [DOI: 10.1007/s13105-019-00672-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 02/28/2019] [Indexed: 11/29/2022]
|
19
|
Abu Bakar MH, Hairunisa N, Zaman Huri H. Reduced mitochondrial DNA content in lymphocytes is associated with insulin resistance and inflammation in patients with impaired fasting glucose. Clin Exp Med 2018; 18:373-382. [DOI: 10.1007/s10238-018-0495-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 03/09/2018] [Indexed: 12/29/2022]
|
20
|
Guyatt AL, Burrows K, Guthrie PAI, Ring S, McArdle W, Day INM, Ascione R, Lawlor DA, Gaunt TR, Rodriguez S. Cardiometabolic phenotypes and mitochondrial DNA copy number in two cohorts of UK women. Mitochondrion 2018; 39:9-19. [PMID: 28818596 PMCID: PMC5832987 DOI: 10.1016/j.mito.2017.08.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 06/06/2017] [Accepted: 08/10/2017] [Indexed: 12/14/2022]
Abstract
The mitochondrial genome is present at variable copy number between individuals. Mitochondria are vulnerable to oxidative stress, and their dysfunction may be associated with cardiovascular disease. The association of mitochondrial DNA copy number with cardiometabolic risk factors (lipids, glycaemic traits, inflammatory markers, anthropometry and blood pressure) was assessed in two independent cohorts of European origin women, one in whom outcomes were measured at mean (SD) age 30 (4.3) years (N=2278) and the second at 69.4 (5.5) years (N=2872). Mitochondrial DNA copy number was assayed by quantitative polymerase chain reaction. Associations were adjusted for smoking, sociodemographic status, laboratory factors and white cell traits. Out of a total of 12 outcomes assessed in both cohorts, mitochondrial DNA copy number showed little or no association with the majority (point estimates were close to zero and nearly all p-values were >0.01). The strongest evidence was for an inverse association in the older cohort with insulin (standardised beta [95%CI]: -0.06, [-0.098, -0.022], p=0.002), but this association did not replicate in the younger cohort. Our findings do not provide support for variation in mitochondrial DNA copy number having an important impact on cardio-metabolic risk factors in European origin women.
Collapse
Affiliation(s)
- Anna L Guyatt
- MRC Integrative Epidemiology Unit, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK; School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK
| | - Kimberley Burrows
- MRC Integrative Epidemiology Unit, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK; School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK
| | - Philip A I Guthrie
- School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK
| | - Sue Ring
- MRC Integrative Epidemiology Unit, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK; School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK
| | - Wendy McArdle
- MRC Integrative Epidemiology Unit, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK; School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK
| | - Ian N M Day
- School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK
| | - Raimondo Ascione
- Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol, UK
| | - Debbie A Lawlor
- MRC Integrative Epidemiology Unit, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK; School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK
| | - Tom R Gaunt
- MRC Integrative Epidemiology Unit, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK; School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK
| | - Santiago Rodriguez
- MRC Integrative Epidemiology Unit, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK; School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK.
| |
Collapse
|
21
|
Jędrak P, Krygier M, Tońska K, Drozd M, Kaliszewska M, Bartnik E, Sołtan W, Sitek EJ, Stanisławska-Sachadyn A, Limon J, Sławek J, Węgrzyn G, Barańska S. Mitochondrial DNA levels in Huntington disease leukocytes and dermal fibroblasts. Metab Brain Dis 2017; 32:1237-1247. [PMID: 28508341 PMCID: PMC5504138 DOI: 10.1007/s11011-017-0026-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 05/01/2017] [Indexed: 12/22/2022]
Abstract
Huntington disease (HD) is an inherited neurodegenerative disorder caused by mutations in the huntingtin gene. Involvement of mitochondrial dysfunctions in, and especially influence of the level of mitochondrial DNA (mtDNA) on, development of this disease is unclear. Here, samples of blood from 84 HD patients and 79 controls, and dermal fibroblasts from 10 HD patients and 9 controls were analysed for mtDNA levels. Although the type of mitochondrial haplogroup had no influence on the mtDNA level, and there was no correlation between mtDNA level in leukocytes in HD patients and various parameters of HD severity, some considerable differences between HD patients and controls were identified. The average mtDNA/nDNA relative copy number was significantly higher in leukocytes, but lower in fibroblasts, of symptomatic HD patients relative to the control group. Moreover, HD women displayed higher mtDNA levels in leukocytes than HD men. Because this is the largest population analysed to date, these results might contribute to explanation of discrepancies between previously published studies concerning levels of mtDNA in cells of HD patients. We suggest that the size of the investigated population and type of cells from which DNA is isolated could significantly affect results of mtDNA copy number estimation in HD. Hence, these parameters should be taken into consideration in studies on mtDNA in HD, and perhaps also in other diseases where mitochondrial dysfunction occurs.
Collapse
Affiliation(s)
- Paulina Jędrak
- Department of Molecular Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland
| | - Magdalena Krygier
- Department of Biology and Genetics, Medical University of Gdańsk, Gdańsk, Poland
| | - Katarzyna Tońska
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Małgorzata Drozd
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Magdalena Kaliszewska
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Ewa Bartnik
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
- Polish Academy of Sciences, Institute of Biochemistry and Biophysics, Warsaw, Poland
| | - Witold Sołtan
- Department of Neurology, St. Adalbert Hospital, Copernicus PL Ltd., Gdańsk, Poland
| | - Emilia J Sitek
- Department of Neurology, St. Adalbert Hospital, Copernicus PL Ltd., Gdańsk, Poland
- Department of Neurological and Psychiatric Nursing, Medical University of Gdańsk, Gdańsk, Poland
| | | | - Janusz Limon
- Department of Biology and Genetics, Medical University of Gdańsk, Gdańsk, Poland
| | - Jarosław Sławek
- Department of Neurology, St. Adalbert Hospital, Copernicus PL Ltd., Gdańsk, Poland
- Department of Neurological and Psychiatric Nursing, Medical University of Gdańsk, Gdańsk, Poland
| | - Grzegorz Węgrzyn
- Department of Molecular Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland
| | - Sylwia Barańska
- Department of Molecular Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland.
- Department of Bacterial Molecular Genetics, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland.
| |
Collapse
|
22
|
Rosa MJ, Just AC, Guerra MS, Kloog I, Hsu HHL, Brennan KJ, García AM, Coull B, Wright RJ, Téllez Rojo MM, Baccarelli AA, Wright RO. Identifying sensitive windows for prenatal particulate air pollution exposure and mitochondrial DNA content in cord blood. ENVIRONMENT INTERNATIONAL 2017; 98:198-203. [PMID: 27843010 PMCID: PMC5139686 DOI: 10.1016/j.envint.2016.11.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 10/12/2016] [Accepted: 11/04/2016] [Indexed: 05/06/2023]
Abstract
INTRODUCTION Changes in mitochondrial DNA (mtDNA) can serve as a marker of cumulative oxidative stress (OS) due to the mitochondria's unique genome and relative lack of repair systems. In utero particulate matter ≤2.5μm (PM2.5) exposure can enhance oxidative stress. Our objective was to identify sensitive windows to predict mtDNA damage experienced in the prenatal period due to PM2.5 exposure using mtDNA content measured in cord blood. MATERIAL AND METHODS Women affiliated with the Mexican social security system were recruited during pregnancy in the Programming Research in Obesity, Growth, Environment and Social Stressors (PROGRESS) study. Mothers with cord blood collected at delivery and complete covariate data were included (n=456). Mothers' prenatal daily exposure to PM2.5 was estimated using a satellite-based spatio-temporally resolved prediction model and place of residence during pregnancy. DNA was extracted from umbilical cord leukocytes. Quantitative real-time polymerase chain reaction (qPCR) was used to determine mtDNA content. A distributive lag regression model (DLM) incorporating weekly averages of daily PM2.5 predictions was constructed to plot the association between exposure and OS over the length of pregnancy. RESULTS In models that included child's sex, mother's age at delivery, prenatal environmental tobacco smoke exposure, birth year, maternal education, and assay batch, we found significant associations between higher PM2.5 exposure during late pregnancy (35-40weeks) and lower mtDNA content in cord blood. CONCLUSIONS Increased PM2.5 during a specific prenatal window in the third trimester was associated with decreased mtDNA content suggesting heightened sensitivity to PM-induced OS during this life stage.
Collapse
Affiliation(s)
- Maria José Rosa
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Allan C Just
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Marco Sánchez Guerra
- Department of Neurobiology, National Institute of Perinatology, Mexico City, Mexico.
| | - Itai Kloog
- Department of Geography and Environmental Development, Ben-Gurion University of the Negev, P.O.B. 653, Beer Sheva, Israel.
| | - Hsiao-Hsien Leon Hsu
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Kasey J Brennan
- Department of Environmental Health Sciences, Columbia University Mailman School of Public Health, New York, NY, USA.
| | - Adriana Mercado García
- Center for Nutrition and Health Research, National Institute of Public Health, Ministry of Health, Cuernavaca, Morelos, Mexico.
| | - Brent Coull
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
| | - Rosalind J Wright
- Kravis Children's Hospital, Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Martha María Téllez Rojo
- Center for Nutrition and Health Research, National Institute of Public Health, Ministry of Health, Cuernavaca, Morelos, Mexico.
| | - Andrea A Baccarelli
- Department of Environmental Health Sciences, Columbia University Mailman School of Public Health, New York, NY, USA.
| | - Robert O Wright
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| |
Collapse
|
23
|
Adjusting MtDNA Quantification in Whole Blood for Peripheral Blood Platelet and Leukocyte Counts. PLoS One 2016; 11:e0163770. [PMID: 27736919 PMCID: PMC5063275 DOI: 10.1371/journal.pone.0163770] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 09/14/2016] [Indexed: 12/28/2022] Open
Abstract
Alterations of mitochondrial DNA copy number (mtDNAcn) in the blood (mitochondrial to nuclear DNA ratio) appear associated with several systemic diseases, including primary mitochondrial disorders, carcinogenesis, and hematologic diseases. Measuring mtDNAcn in DNA extracted from whole blood (WB) instead of from peripheral blood mononuclear cells or buffy coat may yield different results due to mitochondrial DNA present in platelets. The aim of this work is to quantify the contribution of platelets to mtDNAcn in whole blood [mtDNAcn(WB)] and to propose a correction formula to estimate leukocytes' mtDNAcn [mtDNAcn(L)] from mtDNAcn(WB). Blood samples from 10 healthy adults were combined with platelet-enriched plasma and saline solution to produce artificial blood preparations. Aliquots of each sample were combined with five different platelet concentrations. In 46 of these blood preparations, mtDNAcn was measured by qPCR. MtDNAcn(WB) increased 1.07 (95%CI 0.86, 1.29; p<0.001) per 1000 platelets present in the preparation. We proved that leukocyte count should also be taken into account as mtDNAcn(WB) was inversely associated with leukocyte count; it increased 1.10 (95%CI 0.95, 1.25, p<0.001) per unit increase of the ratio between platelet and leukocyte counts. If hematological measurements are available, subtracting 1.10 the platelets/leukocyte ratio from mtDNAcn(WB) may serve as an estimation for mtDNAcn(L). Both platelet and leukocyte counts in the sample are important sources of variation if comparing mtDNAcn among groups of patients when mtDNAcn is measured in DNA extracted from whole blood. Not taking the platelet/leukocyte ratio into account in whole blood measurements, may lead to overestimation and misclassification if interpreted as leukocytes' mtDNAcn.
Collapse
|
24
|
Zhou MC, Zhu L, Cui X, Feng L, Zhao X, He S, Ping F, Li W, Li Y. Reduced peripheral blood mtDNA content is associated with impaired glucose-stimulated islet β cell function in a Chinese population with different degrees of glucose tolerance. Diabetes Metab Res Rev 2016; 32:768-774. [PMID: 27103506 PMCID: PMC5108437 DOI: 10.1002/dmrr.2814] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 02/17/2016] [Accepted: 04/13/2016] [Indexed: 12/15/2022]
Abstract
AIMS Our aim is to explore the associations between mitochondrial DNA (mtDNA) content and basal plasma glucose, plasma glucose after oral glucose administration and oxidative stress in a Chinese population with different levels of glucose tolerance. We also aimed to investigate the effect of mtDNA content on basal and oral glucose-stimulated insulin secretion. METHODS Five hundred and fifty-six Chinese subjects underwent a 75-g, 2-h oral glucose tolerance test. Subjects with diabetes (n = 159), pre-diabetes (n = 197) and normal glucose tolerance (n = 200) were screened. Blood lipid profile was assessed, and levels of the oxidative stress indicators superoxide dismutase, glutathione reductase (GR) and 8-oxo-2'-deoxyguanosine (8-oxo-dG) were measured. Levels of HbA1c , plasma glucose, insulin and C-peptide were also determined. Measurements were taken at 0, 30, 60 and 120 min after 75 g oral glucose tolerance test. Peripheral blood mtDNA content was assessed using a real-time polymerase chain reaction assay. Insulin sensitivity was evaluated by homeostatic model assessment of insulin resistance and Matsuda index (ISIM ). Basal insulin secretion index (HOMA-β), early phase disposition index (DI30 ) and total phase disposition index (DI120 ) indicate insulin levels at different phases of insulin secretion. RESULTS Peripheral blood mtDNA content was positively associated with DI30 and DI120 and was negatively associated with plasma glucose measured 30, 60 and 120 min after oral glucose administration. However, there was no correlation between mtDNA content and basal insulin secretion (HOMA-β), serum lipid or oxidative stress indicators (8-oxo-dG, superoxide dismutase, GR). HbA1c was negatively associated with GR (r = -0.136, p = 0.001). Multiple linear regression analysis showed that reduced peripheral blood mtDNA content increased the risk of impaired glucose-stimulated β cell function (DI30 : β = 0.104, p = 0.019; DI120 : β = 0.116, p = 0.009). CONCLUSIONS Decreased peripheral blood mtDNA content was more closely associated with glucose-stimulated insulin secretion than with basal secretion. Reduction in glucose-stimulated insulin secretion causes postprandial hyperglycaemia. The oxidative stress was probably largely influenced by hyperglycaemia; it was probably that the decreased mt DNA content led to hyperglycaemia, which caused elevated oxidative stress. © 2016 The Authors. Diabetes/Metabolism Research and Reviews Published by John Wiley & Sons Ltd.
Collapse
Affiliation(s)
- Mei-Cen Zhou
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Beijing, China
| | - Lixin Zhu
- Nankou Community Health Service Centers, Beijing, China
| | - Xiangli Cui
- Nankou Community Health Service Centers, Beijing, China
| | | | | | - Shuli He
- Department of Nutrition, Peking Union Medical College Hospital, Beijing, China
| | - Fan Ping
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Beijing, China
| | - Wei Li
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Beijing, China
| | - Yuxiu Li
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Beijing, China.
| |
Collapse
|
25
|
Yoon CY, Park JT, Kee YK, Han SG, Han IM, Kwon YE, Park KS, Lee MJ, Han SH, Kang SW, Yoo TH. Low Mitochondrial DNA Copy Number is Associated With Adverse Clinical Outcomes in Peritoneal Dialysis Patients. Medicine (Baltimore) 2016; 95:e2717. [PMID: 26886611 PMCID: PMC4998611 DOI: 10.1097/md.0000000000002717] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Mitochondrial dysfunction may play an important role in abnormal glucose metabolism and systemic inflammation. We aimed to investigate the relationship between mitochondrial DNA (mtDNA) copy number and clinical outcomes in peritoneal dialysis (PD) patients. We recruited 120 prevalent PD patients and determined mtDNA copy number by PCR. Primary outcome was all-cause mortality, whereas secondary outcomes included cardiovascular events, technical PD failure, and incident malignancy. Cox proportional hazards analysis determined the independent association of mtDNA copy number with outcomes. The mean patient age was 52.3 years; 42.5% were men. The mean log mtDNA copy number was 3.30 ± 0.50. During a follow-up period of 35.4 ± 19.3 months, all-cause mortality and secondary outcomes were observed in 20.0% and 59.2% of patients, respectively. Secondary outcomes were significantly lower in the highest mtDNA copy number group than in the lower groups. In multiple Cox analysis, the mtDNA copy number was not associated with all-cause mortality (lower two vs highest tertile: hazard ratio [HR] = 1.208, 95% confidence interval [CI] = 0.477-3.061). However, the highest tertile group was significantly associated with lower incidences of secondary outcomes (lower two vs highest tertile: HR [95% CI] = 0.494 [0.277-0.882]) after adjusting for confounding factors. The decreased mtDNA copy number was significantly associated with adverse clinical outcomes in PD patients.
Collapse
Affiliation(s)
- Chang-Yun Yoon
- From the Department of Internal Medicine (C-YY, JTP, YKK, SGH, IMH, YEK, KSP, MJL, SHH, S-WK, T-HY), Yonsei University College of Medicine; and Severance Biomedical Science Institute (S-WK, T-HY), Brain Korea 21 PLUS, Yonsei University College of Medicine, Seoul, Korea
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Shoar Z, Goldenthal MJ, De Luca F, Suarez E. Mitochondrial DNA content and function, childhood obesity, and insulin resistance. Endocr Res 2016; 41:49-56. [PMID: 26513277 DOI: 10.3109/07435800.2015.1068797] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVES The objectives of our study were to compare the mitochondrial enzyme activity between obese and non-obese children and to assess the association between mitochondrial DNA content and function and markers of metabolic syndrome. METHODS Clinical and anthropometric data of obese and normal-weight children ages 2-18 years were collected. We collected buccal swabs for mitochondrial respiratory enzymes (complex I, IV, and Citrate Synthase). In obese children only, serum levels of metabolic parameters and mitochondrial DNA from mononuclear cells were quantitated. RESULTS We recruited 75 obese and 65 normal-weight children. There was no difference in respiratory complex enzyme activity levels between obese and normal-weight subjects. In obese subjects, mitochondrial to nuclear DNA (mt/nDNA) ratio was significantly correlated with BMI Z-score and BMI percentile (p < 0.05, and p < 0.01, respectively), and the strength of this correlation was proportionate to the degree of obesity. We did not find any association between mt/nDNA ratio and metabolic parameters. We observed a significant positive association between complex IV activity and fasting insulin level (p < 0.05). Finally, fasting insulin explained 45% of the variation in the complex IV activity level (p < 0.05). CONCLUSION Our findings indicate that mitochondrial DNA content is directly related to obesity, but not to the markers of metabolic syndrome/insulin resistance in children. Longitudinal studies involving larger samples are needed to confirm our findings and help elucidate the relationship between mitochondrial function, adiposity, and insulin resistance.
Collapse
Affiliation(s)
| | - Michael J Goldenthal
- b Section of Child Neurology, St. Christopher's Hospital for Children, Drexel University College of Medicine , Philadelphia , PA , USA
| | | | | |
Collapse
|
27
|
Guo W, Zheng B, Guo D, Cai Z, Wang Y. Association of AluYb8 insertion/deletion polymorphism in the MUTYH gene with mtDNA maintain in the type 2 diabetes mellitus patients. Mol Cell Endocrinol 2015; 409:33-40. [PMID: 25829257 DOI: 10.1016/j.mce.2015.03.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 03/16/2015] [Accepted: 03/23/2015] [Indexed: 12/15/2022]
Abstract
A common AluYb8-element insertion/deletion polymorphism of the MUTYH gene (AluYb8MUTYH) is a novel genetic risk factor for type 2 diabetes mellitus (T2DM). In the present study, mtDNA sequencing analysis indicated that the mtDNA sequence heteroplasmy was not associated with AluYb8MUTYH polymorphism. To better understand the genetic risk for T2DM, we investigated the association of this polymorphism with mtDNA content, mtDNA breakage and mtDNA transcription in the leukocytes of T2DM patients. The mtDNA content and unbroken mtDNA were significantly increased in the mutant patients than in the wild-type patients (P <0.05, respectively). However, no association between mtDNA transcription and AluYb8MUTYH variant was observed. The results suggested that the AluYb8MUTYH variant was associated with an altered mtDNA maintain in T2DM patients. The high level of mtDNA content observed in the mutant patients may have resulted from inefficient base excision repair of mitochondrial MUTYH and a compensatory mechanism that is triggered by elevated oxidative stress.
Collapse
Affiliation(s)
- Wenwen Guo
- Jiangsu Key Laboratory of Molecular Medicine, Nanjing University School of Medicine, No.22 HanKou Road, Nanjing 210093, China; Department of Medical Genetics, Nanjing University School of Medicine, No.22 HanKou Road, Nanjing 210093, China; Clinical Molecular Diagnostic Center, Second Hospital, Nanjing Medical University, No.121 Jiangjiayuan Road, Nanjing 210011, China
| | - Bixia Zheng
- Jiangsu Key Laboratory of Molecular Medicine, Nanjing University School of Medicine, No.22 HanKou Road, Nanjing 210093, China; Department of Medical Genetics, Nanjing University School of Medicine, No.22 HanKou Road, Nanjing 210093, China
| | - Dong Guo
- Jiangsu Key Laboratory of Molecular Medicine, Nanjing University School of Medicine, No.22 HanKou Road, Nanjing 210093, China; Department of Medical Genetics, Nanjing University School of Medicine, No.22 HanKou Road, Nanjing 210093, China
| | - Zhenming Cai
- Jiangsu Key Laboratory of Molecular Medicine, Nanjing University School of Medicine, No.22 HanKou Road, Nanjing 210093, China; Department of Medical Genetics, Nanjing University School of Medicine, No.22 HanKou Road, Nanjing 210093, China
| | - Yaping Wang
- Jiangsu Key Laboratory of Molecular Medicine, Nanjing University School of Medicine, No.22 HanKou Road, Nanjing 210093, China; Department of Medical Genetics, Nanjing University School of Medicine, No.22 HanKou Road, Nanjing 210093, China.
| |
Collapse
|
28
|
Tower J. Mitochondrial maintenance failure in aging and role of sexual dimorphism. Arch Biochem Biophys 2015; 576:17-31. [PMID: 25447815 PMCID: PMC4409928 DOI: 10.1016/j.abb.2014.10.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/08/2014] [Accepted: 10/18/2014] [Indexed: 12/31/2022]
Abstract
Gene expression changes during aging are partly conserved across species, and suggest that oxidative stress, inflammation and proteotoxicity result from mitochondrial malfunction and abnormal mitochondrial-nuclear signaling. Mitochondrial maintenance failure may result from trade-offs between mitochondrial turnover versus growth and reproduction, sexual antagonistic pleiotropy and genetic conflicts resulting from uni-parental mitochondrial transmission, as well as mitochondrial and nuclear mutations and loss of epigenetic regulation. Aging phenotypes and interventions are often sex-specific, indicating that both male and female sexual differentiation promote mitochondrial failure and aging. Studies in mammals and invertebrates implicate autophagy, apoptosis, AKT, PARP, p53 and FOXO in mediating sex-specific differences in stress resistance and aging. The data support a model where the genes Sxl in Drosophila, sdc-2 in Caenorhabditis elegans, and Xist in mammals regulate mitochondrial maintenance across generations and in aging. Several interventions that increase life span cause a mitochondrial unfolded protein response (UPRmt), and UPRmt is also observed during normal aging, indicating hormesis. The UPRmt may increase life span by stimulating mitochondrial turnover through autophagy, and/or by inhibiting the production of hormones and toxic metabolites. The data suggest that metazoan life span interventions may act through a common hormesis mechanism involving liver UPRmt, mitochondrial maintenance and sexual differentiation.
Collapse
Affiliation(s)
- John Tower
- Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089-2910, United States.
| |
Collapse
|
29
|
Alvarado-Vásquez N. Circulating cell-free mitochondrial DNA as the probable inducer of early endothelial dysfunction in the prediabetic patient. Exp Gerontol 2015; 69:70-8. [PMID: 26026597 DOI: 10.1016/j.exger.2015.05.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 05/09/2015] [Accepted: 05/25/2015] [Indexed: 12/16/2022]
Abstract
Recent evidence has shown that 346million people in the world have diabetes mellitus (DM); this number will increase to 439million by 2030. In addition, current data indicate an increase in DM cases in the population between 40 and 59years of age. Diabetes is associated with the development of micro- and macro-vascular complications, derived from chronic hyperglycemia on the endothelium. Some reports demonstrate that people in a prediabetic state have a major risk of developing early endothelial dysfunction (ED). Today, it is accepted that individuals considered as prediabetic patients are in a pro-inflammatory state associated with endothelial and mitochondrial dysfunction. It is important to mention that impaired mitochondrial functionality has been linked to endothelial apoptosis and release of mitochondrial DNA (mtDNA) in patients with sepsis, cardiac disease, or atherosclerosis. This free mtDNA could promote ED, as well as other side effects on the vascular system through the activation of the toll-like receptor 9 (TLR9). TLR9 is expressed in different cell types (e.g., T or B lymphocytes, mastocytes, and epithelial and endothelial cells). It is localized intracellularly and recognizes non-methylated dinucleotides of viral, bacterial, and mitochondrial DNA. Recently, it has been reported that TLR9 is associated with the pathogenesis of lupus erythematosus, rheumatoid arthritis, and autoimmune diabetes. In this work, it is hypothesized that the increase in the levels of circulating mtDNA is the trigger of early ED in the prediabetic patient, and later on in the older patient with diabetes, through activation of the TLR9 present in the endothelium.
Collapse
Affiliation(s)
- Noé Alvarado-Vásquez
- Department of Biochemistry, National Institute of Respiratory Diseases "Ismael Cosío Villegas", Calz. de Tlalpan 4502, Col. Sección XVI, 14080 Mexico, D.F., Mexico, Mexico.
| |
Collapse
|
30
|
Abnormal mitochondrial function and impaired granulosa cell differentiation in androgen receptor knockout mice. Int J Mol Sci 2015; 16:9831-49. [PMID: 25941928 PMCID: PMC4463620 DOI: 10.3390/ijms16059831] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 04/20/2015] [Accepted: 04/22/2015] [Indexed: 01/23/2023] Open
Abstract
In the ovary, the paracrine interactions between the oocyte and surrounded granulosa cells are critical for optimal oocyte quality and embryonic development. Mice lacking the androgen receptor (AR−/−) were noted to have reduced fertility with abnormal ovarian function that might involve the promotion of preantral follicle growth and prevention of follicular atresia. However, the detailed mechanism of how AR in granulosa cells exerts its effects on oocyte quality is poorly understood. Comparing in vitro maturation rate of oocytes, we found oocytes collected from AR−/− mice have a significantly poor maturating rate with 60% reached metaphase II and 30% remained in germinal vesicle breakdown stage, whereas 95% of wild-type AR (AR+/+) oocytes had reached metaphase II. Interestingly, we found these AR−/− female mice also had an increased frequency of morphological alterations in the mitochondria of granulosa cells with reduced ATP generation (0.18 ± 0.02 vs. 0.29 ± 0.02 µM/mg protein; p < 0.05) and aberrant mitochondrial biogenesis. Mechanism dissection found loss of AR led to a significant decrease in the expression of peroxisome proliferator-activated receptor γ (PPARγ) co-activator 1-β (PGC1-β) and its sequential downstream genes, nuclear respiratory factor 1 (NRF1) and mitochondrial transcription factor A (TFAM), in controlling mitochondrial biogenesis. These results indicate that AR may contribute to maintain oocyte quality and fertility via controlling the signals of PGC1-β-mediated mitochondrial biogenesis in granulosa cells.
Collapse
|
31
|
Indoxyl sulfate-induced oxidative stress, mitochondrial dysfunction, and impaired biogenesis are partly protected by vitamin C and N-acetylcysteine. ScientificWorldJournal 2015; 2015:620826. [PMID: 25839054 PMCID: PMC4369955 DOI: 10.1155/2015/620826] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 09/14/2014] [Accepted: 09/15/2014] [Indexed: 11/28/2022] Open
Abstract
Indoxyl sulfate (IS) contributes to oxidative stress and endothelial dysfunction in chronic kidney disease patients. However, the role of mitochondria in IS-induced oxidative stress is not very clear. In this study, we examined whether mitochondria play a pivotal role in modulating the effects of antioxidants during IS treatment. In the context of human umbilical vein endothelial cells, we found that IS had a dose-dependent antiproliferative effect. In addition, we used flow cytometry to demonstrate that the level of reactive oxygen species increased in a dose-dependent manner after treatment with IS. High doses of IS also corresponded to increased mitochondrial depolarization and decreased mitochondrial DNA copy number and mitochondrial mass. However, these effects could be reversed by the addition of antioxidants, namely, vitamin C and N-acetylcysteine. Thus, our results suggest that IS-induced oxidative stress and antiproliferative effect can be attributed to mitochondrial dysfunction and impaired biogenesis and that these processes can be protected by treatment with antioxidants.
Collapse
|
32
|
López S, Buil A, Souto JC, Casademont J, Martinez-Perez A, Almasy L, Soria JM. A genome-wide association study in the genetic analysis of idiopathic thrombophilia project suggests sex-specific regulation of mitochondrial DNA levels. Mitochondrion 2014; 18:34-40. [PMID: 25240745 DOI: 10.1016/j.mito.2014.09.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 08/24/2014] [Accepted: 09/10/2014] [Indexed: 12/20/2022]
Abstract
Identifying genes that regulate mitochondrial DNA (mtDNA) levels is of interest due to an increasing number of diseases in humans that are associated with altered mtDNA levels. We searched for nuclear polymorphisms that influence mtDNA levels using a family-based genome-wide association (GWAS) method. Also, our aim was to determine if sex influences the genetic control of mtDNA levels. Two intron-polymorphisms, in the genes PARK2 and MRPL37, showed a tendency toward an association with mtDNA levels only in females and only in males, respectively. Both genes have a role in mitochondrial biogenesis and are potential candidates for the sex-specific control of mtDNA levels.
Collapse
Affiliation(s)
- Sonia López
- Unit of Genomic of Complex Diseases, Research Institute of Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.
| | - Alfonso Buil
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva, Switzerland
| | - Juan Carlos Souto
- Haemostasis and Thrombosis Unit, Department of Haematology, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Jordi Casademont
- Internal Medicine Department, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Angel Martinez-Perez
- Unit of Genomic of Complex Diseases, Research Institute of Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Laura Almasy
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - José Manuel Soria
- Unit of Genomic of Complex Diseases, Research Institute of Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| |
Collapse
|
33
|
Abstract
The oversupply of calories and sedentary lifestyle has resulted in a rapid increase of diabetes prevalence worldwide. During the past two decades, lines of evidence suggest that mitochondrial dysfunction plays a key role in the pathophysiology of diabetes. Mitochondria are vital to most of the eukaryotic cells as they provide energy in the form of adenosine triphosphate by oxidative phosphorylation. In addition, mitochondrial function is an integral part of glucose-stimulated insulin secretion in pancreatic β-cells. In the present article, we will briefly review the major functions of mitochondria in regard to energy metabolism, and discuss the genetic and environmental factors causing mitochondrial dysfunction in diabetes. In addition, the pathophysiological role of mitochondrial dysfunction in insulin resistance and β-cell dysfunction are discussed. We argue that mitochondrial dysfunction could be the central defect causing the abnormal glucose metabolism in the diabetic state. A deeper understanding of the role of mitochondria in diabetes will provide us with novel insights in the pathophysiology of diabetes. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2010.00047.x, 2010).
Collapse
Affiliation(s)
| | - Kyong Soo Park
- Departments of Internal Medicine ; Molecular Medicine and Biopharmaceutical Sciences, Seoul National University College of Medicine
| | - Ki-Up Lee
- Department of Internal Medicine, University of Ulsan College of Medicine
| | - Hong Kyu Lee
- Department of Internal Medicine, Eulji University College of Medicine, Seoul, Korea
| |
Collapse
|
34
|
Wang PW, Kuo HM, Huang HT, Chang AYW, Weng SW, Tai MH, Chuang JH, Chen IY, Huang SC, Lin TK, Liou CW. Biphasic response of mitochondrial biogenesis to oxidative stress in visceral fat of diet-induced obesity mice. Antioxid Redox Signal 2014; 20:2572-88. [PMID: 24111683 PMCID: PMC4025601 DOI: 10.1089/ars.2013.5334] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
AIMS Studies in skeletal muscle demonstrate a strong association of mitochondrial dysfunction with insulin resistance (IR). However, there is still a paucity of knowledge regarding the alteration of mitochondria in adipose tissue (AT) in the pathogenesis of IR in obesity. We investigated the mitochondrial biogenesis in visceral fat (VF) and subcutaneous fat (SF) in C57BL/6J mice fed a high-fat high-sucrose diet for 12 months. RESULTS Impairment of glucose tolerance and insulin sensitivity developed after 1 month of the diet and was associated with a prompt increase of VF. The VF adipocytes were larger than those in the SF and had increased expressions of HIF-1α and p-NFκB p65. However, the alteration of mitochondrial biogenesis did not occur in the early stage when increased intracellular reactive oxygen species (ROS), mitochondrial oxygen consumption rate, and mitochondrial ROS emerged at the 1st, 2nd and 2nd month, respectively. Until the 6th month, the VF had markedly increased mitochondrial DNA content and expression of PGC-1α, Tfam, ATP5A, and MnSOD. This increase of mitochondrial biogenesis was followed by a generalized decrease at the 12th month and the mitochondrial morphology altered markedly. In the late stage, although mitochondrial ROS decreased, the increased expression of 8-OHdG in VF continued. INNOVATION AND CONCLUSION These data suggest that IR and ROS production occur before the biphasic changes of mitochondrial biogenesis in AT, and the VF plays a more crucial role.
Collapse
Affiliation(s)
- Pei-Wen Wang
- Department of Internal Medicine, Chang Gung University College of Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Hsiao-Mei Kuo
- Department of Internal Medicine, Chang Gung University College of Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Hung-Tu Huang
- Department of Anatomy, College of Medicine, School of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Alice YW Chang
- Center for Translational Research in Biomedical Sciences, Chang Gung University College of Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Shao-Wen Weng
- Department of Internal Medicine, Chang Gung University College of Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Ming-Hong Tai
- Department of Biological Sciences, Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - Jiin-Haur Chuang
- Department of Surgery, Chang Gung University College of Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - I-Ya Chen
- Department of Internal Medicine, Chang Gung University College of Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Shun-Chen Huang
- Department of Anatomic Pathology, Chang Gung University College of Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Tsu-Kung Lin
- Department of Neurology, Chang Gung University College of Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Chia-Wei Liou
- Department of Neurology, Chang Gung University College of Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| |
Collapse
|
35
|
Kim JH, Kim HK, Ko JH, Bang H, Lee DC. The relationship between leukocyte mitochondrial DNA copy number and telomere length in community-dwelling elderly women. PLoS One 2013; 8:e67227. [PMID: 23785520 PMCID: PMC3681770 DOI: 10.1371/journal.pone.0067227] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 05/15/2013] [Indexed: 12/19/2022] Open
Abstract
Purpose Both telomere length and mitochondrial function are accepted as reflective indices of aging. Recent studies have shown that telomere dysfunction may influence impaired mitochondrial biogenesis and function. However, there has been no study regarding the possible association between telomere and mitochondrial function in humans. Therefore, the purpose of the study was to identify any relationships between mitochondrial and telomere function. Methods The present study included 129 community-dwelling, elderly women. The leukocyte mitochondrial DNA copy number and telomere length were measured using a quantitative real-time polymerase chain reaction method. Anthropometric measurement, biochemical blood testing, a depression screening questionnaire using a 15-question geriatric depression scale (GDS-15), and a cognitive function test using the Korean version of the mini mental state examination (K-MMSE) were performed. Results Leukocyte mtDNA copy number was positively associated with telomere length (r=0.39, p=<0.0001) and K-MMSE score (r=0.06, p=0.02). Additionally, leukocyte mtDNA copy number was negatively correlated with GDS-15 score (r=-0.17, p=0.04). Age (r=-0.15, p=0.09), waist circumference (r=-0.16, p=0.07), and serum ferritin level (r=-0.13, p=0.07) tended to be inversely correlated with leukocyte mtDNA copy number. With a stepwise multiple regression analysis, telomere length was found to be an independent factor associated with leukocyte mtDNA copy number after adjustment for confounding variables including age, body mass index, waist circumference, total cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides, hs-CRP, serum ferritin, HOMA-IR, K-MMSE, GDS-15, hypertension, diabetes, dyslipidemia, currently smoking, alcohol drinking, and regular exercise. Conclusions This study showed that leukocyte mtDNA copy number was positively correlated with leukocyte telomere length in community-dwelling elderly women. Our findings suggest that telomere function may influence mitochondrial function in humans.
Collapse
Affiliation(s)
- Jung-Ha Kim
- Department of Family Medicine, Chung-Ang University Healthcare System, Seoul, Korea
| | - Hye Kyung Kim
- Health Promotion Center, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Jae-Hong Ko
- Department of Physiology, College of Medicine, Chung-Ang University, Seoul, Korea
| | - Hyoweon Bang
- Department of Physiology, College of Medicine, Chung-Ang University, Seoul, Korea
- * E-mail: (D-CL); (HB)
| | - Duk-Chul Lee
- Department of Family Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
- * E-mail: (D-CL); (HB)
| |
Collapse
|
36
|
Wen B, Li D, Shan J, Liu S, Li W, Zhao Y, Lin P, Zheng J, Li D, Gong Y, Yan C. Increased muscle coenzyme Q10 in riboflavin responsive MADD with ETFDH gene mutations due to secondary mitochondrial proliferation. Mol Genet Metab 2013; 109:154-60. [PMID: 23628458 DOI: 10.1016/j.ymgme.2013.04.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 04/04/2013] [Indexed: 11/30/2022]
Abstract
Multiple acyl-coenzyme A dehydrogenation deficiency (MADD) has a wide range of phenotypic variation ranging from a neonatal lethal form to a mild late-onset form. Our previous data showed that in a group of Chinese patients, a mild type of MADD characterized by myopathy with clinically no other systemic involvement was caused by mutations in electron transfer flavoprotein dehydrogenase (ETFDH) gene, which encodes electron transfer flavoprotein: ubiquinone oxidoreductase (ETF:QO). Coenzyme Q10 (CoQ10), a downstream electron receptor of ETF:QO was first reported deficient in muscle of MADD patients with ETFDH gene mutations. Nevertheless, this result was not confirmed in a recently published study. Therefore to elucidate muscle CoQ10 level in a large group of MADD patients may provide further insight into the pathomechanism and therapeutic strategies. In this study, we found that 34 riboflavin responsive patients with ETFDH gene mutations had an elevated CoQ10 pool in muscle by high performance liquid chromatography (HPLC). However, when CoQ10 levels were normalized to citrate synthase, a marker of mitochondrial mass, there was no significant difference between patients and normal controls. Meanwhile, the increased mitochondrial DNA copy number in muscle also supported that the elevated CoQ10 pool was mainly due to mitochondrial mass proliferation. The expression of CoQ10 biosynthesis genes showed no significant changes whereas genes involved in lipid metabolism, such as PPARα, were marked up regulated. Our results suggested that CoQ10 seems not to be a primary factor in riboflavin responsive MADD and the apparent increase in CoQ10 may be secondary to mitochondrial proliferation.
Collapse
Affiliation(s)
- Bing Wen
- Laboratory of Neuromuscular Disorders, Brain Science Research Institute and Department of Neurology, Qilu Hospital, Shandong University, Jinan, 250012, China
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Hou L, Zhang X, Dioni L, Barretta F, Dou C, Zheng Y, Hoxha M, Bertazzi PA, Schwartz J, Wu S, Wang S, Baccarelli AA. Inhalable particulate matter and mitochondrial DNA copy number in highly exposed individuals in Beijing, China: a repeated-measure study. Part Fibre Toxicol 2013; 10:17. [PMID: 23628000 PMCID: PMC3649952 DOI: 10.1186/1743-8977-10-17] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 04/12/2013] [Indexed: 12/30/2022] Open
Abstract
Background Mitochondria are both a sensitive target and a primary source of oxidative stress, a key pathway of air particulate matter (PM)-associated diseases. Mitochondrial DNA copy number (MtDNAcn) is a marker of mitochondrial damage and malfunctioning. We evaluated whether ambient PM exposure affects MtDNAcn in a highly-exposed population in Beijing, China. Methods The Beijing Truck Driver Air Pollution Study was conducted shortly before the 2008 Beijing Olympic Games (June 15-July 27, 2008) and included 60 truck drivers and 60 office workers. Personal PM2.5 and elemental carbon (EC, a tracer of traffic particles) were measured during work hours using portable monitors. Post-work blood samples were obtained on two different days. Ambient PM10 was averaged from 27 monitoring stations in Beijing. Blood MtDNAcn was determined by real-time PCR and examined in association with particle levels using mixed-effect models. Results In all participants combined, MtDNAcn was negatively associated with personal EC level measured during work hours (β=−0.059, 95% CI: -0.011; -0.0006, p=0.03); and 5-day (β=−0.017, 95% CI: -0.029;-0.005, p=0.01) and 8-day average ambient PM10 (β=−0.008, 95% CI: -0.043; -0.008, p=0.004) after adjusting for possible confounding factors, including study groups. MtDNAcn was also negatively associated among office workers with EC (β=−0.012, 95% CI: -0.022;-0.002, p=0.02) and 8-day average ambient PM10 (β=−0.030, 95% CI: -0.051;-0.008, p=0.007). Conclusions We observed decreased blood MtDNAcn in association with increased exposure to EC during work hours and recent ambient PM10 exposure. Our results suggest that MtDNAcn may be influenced by particle exposures. Further studies are required to determine the roles of MtDNAcn in the etiology of particle-related diseases.
Collapse
Affiliation(s)
- Lifang Hou
- Department of Preventive Medicine Feinberg, School of Medicine Northwestern University, Chicago, IL 60611, USA.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Simultaneous quantification of mitochondrial DNA damage and copy number in circulating blood: a sensitive approach to systemic oxidative stress. BIOMED RESEARCH INTERNATIONAL 2012; 2013:157547. [PMID: 23484085 PMCID: PMC3591215 DOI: 10.1155/2013/157547] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Revised: 11/12/2012] [Accepted: 11/13/2012] [Indexed: 12/25/2022]
Abstract
Systemic oxidative stress is associated with a wide range of pathological conditions. Oxidative DNA damage is frequently measured in circulating lymphocytes. Mitochondrial DNA (mtDNA) is known to be more sensitive to oxidative damage than nuclear DNA but is rarely used for direct measurement of DNA damage in clinical studies. Based on the supercoiling-sensitive real-time PCR method, we propose a new approach for the noninvasive monitoring of systemic oxidative stress by quantifying the mtDNA structural damage and copy number change in isolated lymphocytes in a single test. We show that lymphocytes have significantly less mtDNA content and relatively lower baseline levels of damage than cancer cell lines. In an ex vivo challenge experiment, we demonstrate, for the first time, that exogenous H2O2 induces a significant increase in mtDNA damage in lymphocytes from healthy individuals, but no repair activity is observed after 1 h recovery. We further demonstrate that whole blood may serve as a convenient alternative to the isolated lymphocytes in mtDNA analysis. Thus, the blood analysis with the multiple mtDNA end-points proposed in the current study may provide a simple and sensitive test to interrogate the nature and extent of systemic oxidative stress for a broad spectrum of clinical investigations.
Collapse
|
39
|
Malik AN, Czajka A. Is mitochondrial DNA content a potential biomarker of mitochondrial dysfunction? Mitochondrion 2012; 13:481-92. [PMID: 23085537 DOI: 10.1016/j.mito.2012.10.011] [Citation(s) in RCA: 339] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 10/10/2012] [Accepted: 10/11/2012] [Indexed: 12/17/2022]
Abstract
Mitochondrial dysfunction is central to numerous diseases of oxidative stress. Changes in mitochondrial DNA (MtDNA) content, often measured as mitochondrial genome to nuclear genome ratio (Mt/N) using real time quantitative PCR, have been reported in a broad range of human diseases, such as diabetes and its complications, obesity, cancer, HIV complications, and ageing. We propose the hypothesis that MtDNA content in body fluids and tissues could be a biomarker of mitochondrial dysfunction and review the evidence supporting this theory. Increased reactive oxygen species resulting from an external trigger such as hyperglycaemia or increased fat in conditions of oxidative stress could lead to enhanced mitochondrial biogenesis, and increased Mt/N. Altered MtDNA levels may contribute to enhanced oxidative stress and inflammation and could play a pathogenic role in mitochondrial dysfunction and disease. Changes in Mt/N are detectable in circulating cells such as peripheral blood mononuclear cells and these could be used as surrogate to predict global changes in tissues and organs. We review a large number of studies reporting changes in MtDNA levels in body fluids such as circulating blood cells, cell free serum, saliva, sperm, and cerebrospinal fluid as well as in tumour and normal tissue samples. However, the data are often conflicting as the current methodology used to measure Mt/N can give false results because of one or more of the following reasons (1) use of mitochondrial primers which co-amplify nuclear pseudogenes (2) use of nuclear genes which are variable and/or duplicated in numerous locations (3) a dilution bias caused by the differing genome sizes of the mitochondrial and nuclear genome and (4) template preparation protocols which affect the yields of nuclear and mitochondrial genomes. Development of robust and reproducible methodology is needed to test the hypothesis that MtDNA content in body fluids is biomarker of mitochondrial dysfunction.
Collapse
Affiliation(s)
- Afshan N Malik
- Diabetes Research Group, Division of Diabetes and Nutritional Sciences, School of Medicine, King's college London, London, UK.
| | | |
Collapse
|
40
|
López S, Buil A, Souto JC, Casademont J, Blangero J, Martinez-Perez A, Fontcuberta J, Lathrop M, Almasy L, Soria JM. Sex-specific regulation of mitochondrial DNA levels: genome-wide linkage analysis to identify quantitative trait loci. PLoS One 2012; 7:e42711. [PMID: 22916149 PMCID: PMC3423410 DOI: 10.1371/journal.pone.0042711] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Accepted: 07/10/2012] [Indexed: 01/27/2023] Open
Abstract
Altered mitochondrial DNA (mtDNA) levels have been associated with common diseases in humans. We investigated the genetic mechanism that controls mtDNA levels using genome-wide linkage analyses in families from the Genetic Analysis of Idiopathic Thrombophilia Project (GAIT). We measure mtDNA levels by quantitative real-time PCR in 386 subjects from 21 extended Spanish families. A variance component linkage method using 485 microsatellites was conducted to evaluate linkage and to detect quantitative trait loci (QTLs) involved in the control of mtDNA levels. The heritalibility of mtDNA levels was 0.33 (p=1.82e-05). We identified a QTL on Chromosome 2 (LOD=2.21) using all of the subjects, independently on their sex. When females and males were analysed separately, three QTLs were identified. Females showed the same QTL on Chromosome 2 (LOD=3.09), indicating that the QTL identified in the analysis using all of the subjects was a strong female QTL, and another one on Chromosome 3 (LOD=2.67), whereas in males a QTL was identified on Chromosome 1 (LOD=2.81). These QTLs were fine-mapped to find associations with mtDNA levels. The most significant SNP association was for the rs10888838 on Chromosome 1 in males. This SNP mapped to the gene MRPL37, involved in mitochondrial protein translation. The rs2140855 on Chromosome 2 showed association in the analysis using all of the subjects. It was near the gene CMPK2, which encodes a mitochondrial enzyme of the salvage pathway of deoxyribonucleotide synthesis. Our results provide evidence of a sex-specific genetic mechanism for the control of mtDNA levels and provide a framework to identify new genes that influence mtDNA levels.
Collapse
Affiliation(s)
- Sonia López
- Unit of Genomic of Complex Diseases, Institute of Biomedical Research of Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Alfonso Buil
- Unit of Genomic of Complex Diseases, Institute of Biomedical Research of Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Juan Carlos Souto
- Haemostasis and Thrombosis Unit, Department of Haematology, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Jordi Casademont
- Internal Medicine Department, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - John Blangero
- Department of Population Genetics, Texas Biomedical Research Institute, San Antonio, Texas, United States of America
| | - Angel Martinez-Perez
- Unit of Genomic of Complex Diseases, Institute of Biomedical Research of Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Jordi Fontcuberta
- Haemostasis and Thrombosis Unit, Department of Haematology, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Mark Lathrop
- Institut de Génomique, Centre National de Génotypage, Evry, France
| | - Laura Almasy
- Department of Population Genetics, Texas Biomedical Research Institute, San Antonio, Texas, United States of America
| | - Jose Manuel Soria
- Unit of Genomic of Complex Diseases, Institute of Biomedical Research of Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| |
Collapse
|
41
|
Xu FX, Zhou X, Shen F, Pang R, Liu SM. Decreased peripheral blood mitochondrial DNA content is related to HbA1c, fasting plasma glucose level and age of onset in type 2 diabetes mellitus. Diabet Med 2012; 29:e47-54. [PMID: 22211946 DOI: 10.1111/j.1464-5491.2011.03565.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS Mitochondrial DNA (mtDNA) content is essential for maintaining normal mitochondrial function, and the mitochondrial function is critical for the production and the release of insulin in Type 2 diabetes mellitus. We investigated whether peripheral blood mtDNA content was reduced in Type 2 diabetes, and what were the major factors? METHODS The mtDNA content of peripheral blood in a sample of 147 Type 2 diabetes and 170 normal Chinese subjects was determined by amplification of the mitochondrial gene CYT-B and normalized by a nuclear DNA β-globin gene. Fasting plasma glucose, HbA(1c) , fasting plasma insulin and lipid profile (HDL-cholesterol, LDL-cholesterol, total cholesterol, triglyceride) were analysed with commercial kits on an automatic analyser. RESULTS In Type 2 diabetes group, the mean HbA(1c) was 62 mmol/mol (7.8%). Moreover, BMI, systolic blood pressure, diastolic blood pressure, fasting plasma glucose, LDL-cholesterol, triglyceride, fasting plasma insulin and homeostasis model assessment for insulin resistance were significantly higher in Type 2 diabetes group than that in control group. Peripheral blood mtDNA content was 24% lower than that in the controls (1.4 ± 0.5 vs. 1.8 ± 0.7, P < 0.001). The mtDNA content was negatively correlated with BMI, fasting plasma glucose, fasting plasma insulin, homeostasis model assessment for insulin resistance (P < 0.01), and age, triglyceride and LDL-cholesterol levels (P < 0.05); while positively correlated with HDL-cholesterol level (P < 0.05) in both groups. Stepwise regression analysis indicated that HbA(1c), fasting plasma glucose and age of onset were the major factors affecting the mtDNA content in the Type 2 diabetes group; however, BMI was the only variable associated with lower mtDNA content in control group. CONCLUSION Our results demonstrate that lower peripheral blood mtDNA content is associated with Type 2 diabetes in Chinese individuals, and HbA(1c), fasting plasma glucose and age of onset are the major factors affecting the mtDNA content.
Collapse
Affiliation(s)
- F X Xu
- Center for Gene Diagnosis, Zhongnan Hospital, Wuhan University, Wuhan, China
| | | | | | | | | |
Collapse
|
42
|
Kim JH, Lee DC. Mitochondrial DNA copy number in peripheral blood is associated with femoral neck bone mineral density in postmenopausal women. J Rheumatol 2012; 39:1465-72. [PMID: 22589267 DOI: 10.3899/jrheum.111444] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE It has been suggested that mitochondrial dysfunction is related to aging and metabolic disorders. Yet there are few studies of the relationship between bone mineral density (BMD) and mitochondrial content in humans. We investigated the relationship between BMD and mitochondrial DNA (mtDNA) copy number in peripheral blood of postmenopausal women. METHODS The study included 146 postmenopausal women. Enrolled subjects were taking no medications and had no disorders that altered bone metabolism. We measured BMD using dual-energy x-ray absorptiometry and leukocyte mtDNA copy number using real-time polymerase chain reaction. Anthropometric evaluations and biochemical tests were performed. RESULTS Patients with osteopenia or osteoporosis had lower mtDNA copy numbers than normal subjects (p < 0.0001). Femoral neck BMD was negatively correlated with age (r = -0.01, p = 0.04) and with serum levels of adiponectin (r = -0.22, p = 0.01) and osteocalcin (r = -0.31, p = 0.0001). Serum levels of 25-OH vitamin D (r = 0.32, p < 0.0001) and mtDNA copy number (r = 0.36, p < 0.0001) were positively correlated with femoral neck BMD. Multiple regression analysis showed that mtDNA copy number (ß = 0.156, p < 0.001) was an independent factor associated with femoral neck BMD after adjustment for age, body mass index, waist circumference, waist-hip ratio, blood pressure, homeostatic model assessment of insulin resistance, high-sensitivity C-reactive protein, adiponectin, osteocalcin, homocysteine, lipid profiles, 25-OH vitamin D, and regular exercise. mtDNA copy number was not related to lumbar BMD. CONCLUSION Low mtDNA content in peripheral blood is related to decreased femoral neck BMD in postmenopausal women. Our findings suggest that mitochondrial dysfunction may be a potential pathophysiologic mechanism of osteoporosis in postmenopausal women.
Collapse
Affiliation(s)
- Jung-Ha Kim
- Department of Family Medicine, Chung-Ang University Healthcare Center, Korea
| | | |
Collapse
|
43
|
Jun DW, Cho WK, Jun JH, Kwon HJ, Jang KS, Kim HJ, Jeon HJ, Lee KN, Lee HL, Lee OY, Yoon BC, Choi HS, Hahm JS, Lee MH. Prevention of free fatty acid-induced hepatic lipotoxicity by carnitine via reversal of mitochondrial dysfunction. Liver Int 2011; 31:1315-24. [PMID: 22093454 DOI: 10.1111/j.1478-3231.2011.02602.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Accepted: 06/28/2011] [Indexed: 12/12/2022]
Abstract
BACKGROUND Mitochondria are the main sites for fatty acid oxidation and play a central role in lipotoxicity and nonalcoholic steatohepatitis. AIMS We investigated whether carnitine prevents free fatty acid (FFA)-induced lipotoxicity in vitro and in vivo. METHODS HepG2 cells were incubated with FFA, along with carnitine and carnitine complexes. Mitochondrial β-oxidation, transmembrane potential, intracellular ATP levels and changes in mitochondrial copy number and morphology were analysed. Otsuka Long-Evans Tokushima Fatty and Long-Evans Tokushima Otsuka rats were segregated into three experimental groups and fed for 8 weeks with (i) normal chow, (ii) a methionine choline-deficient (MCD) diet or (iii) an L-carnitine-supplemented MCD diet. RESULTS Carnitine prevented FFA-induced apoptosis (16% vs. 3%, P < 0.05). FFA treatment resulted in swollen mitochondria with increased inner matrix density and loss of cristae. However, mitochondria co-treated with carnitine had normal ultrastructure. The mitochondrial DNA copy number was higher in the carnitine treatment group than in the palmitic acid treatment group (375 vs. 221 copies, P < 0.05). The carnitine group showed higher mitochondrial β-oxidation than did the control and palmitic acid treatment groups (597 vs. 432 and 395 ccpm, P < 0.05). Carnitine treatment increased the mRNA expression of carnitine palmitoyltransferase 1A and peroxisome proliferator-activated receptor-γ, and carnitine-lipoic acid further augmented the mRNA expression. In the in vivo model, carnitine-treated rats showed lower alanine transaminase levels and lesser lobular inflammation than did the MCD-treated rats. CONCLUSIONS Carnitine and carnitine-lipoic acid prevent lipotoxicity by increasing mitochondrial β-oxidation and reducing intracellular oxidative stress.
Collapse
Affiliation(s)
- Dae Won Jun
- Department of Internal Medicine, Hanyang University School of Medicine, Seoul, Korea.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Lynch SM, Weinstein SJ, Virtamo J, Lan Q, Liu CS, Cheng WL, Rothman N, Albanes D, Stolzenberg-Solomon RZ. Mitochondrial DNA copy number and pancreatic cancer in the alpha-tocopherol beta-carotene cancer prevention study. Cancer Prev Res (Phila) 2011; 4:1912-9. [PMID: 21859925 DOI: 10.1158/1940-6207.capr-11-0002] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Diabetes, obesity, and cigarette smoke, consistent risk factors for pancreatic cancer, are sources of oxidative stress in humans that could cause mitochondrial DNA (mtDNA) damage and increase mtDNA copy number. To test whether higher mtDNA copy number is associated with increased incident pancreatic cancer, we conducted a nested case-control study in the Alpha-Tocopherol Beta Carotene Cancer Prevention (ATBC) Study cohort of male smokers, aged 50 to 69 years at baseline. Between 1992 and 2004, 203 incident cases of pancreatic adenocarcinoma occurred (follow-up: 12 years) among participants, with whole blood samples used for mtDNA extraction. For these cases and 656 controls, we calculated ORs and 95% CIs using unconditional logistic regression, adjusting for age, smoking, and diabetes history. All statistical tests were two sided. Higher mtDNA copy number was significantly associated with increased pancreatic cancer risk (highest vs. lowest mtDNA copy number quintile, OR = 1.64, 95% CI = 1.01-2.67, continuous OR = 1.14, 95% CI 1.06-1.23), particularly for cases diagnosed during the first 7 years of follow-up (OR = 2.14, 95% CI = 1.16-3.96, P(trend) = 0.01, continuous OR = 1.21, 95% CI = 1.10-1.33), but not for cases occurring during follow-up of 7 years or greater (OR = 1.14, 95% CI = 0.53-2.45, continuous OR = 1.05, 95% CI = 0.93-1.18). Our results support the hypothesis that mtDNA copy number is associated with pancreatic cancer and could possibly serve as a biomarker for pancreatic cancer development.
Collapse
Affiliation(s)
- Shannon M Lynch
- Nutritional Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, 6120 Executive Blvd., Rockville, MD 20852, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Hsieh CJ, Weng SW, Liou CW, Lin TK, Chen JB, Tiao MM, Hung YT, Chen IY, Huang WT, Wang PW. Tissue-specific differences in mitochondrial DNA content in type 2 diabetes. Diabetes Res Clin Pract 2011; 92:106-10. [PMID: 21281975 DOI: 10.1016/j.diabres.2011.01.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 12/29/2010] [Accepted: 01/10/2011] [Indexed: 11/29/2022]
Abstract
BACKGROUND To investigate whether the effect of hyperglycemia on mitochondrial DNA (mtDNA) content is tissue-specific. METHOD We compared the mtDNA contents in leg muscle, blood vessel, and peripheral leucocytes in seventeen patients with type 2 diabetes (T2DM) with those of seven controls. We measured 8-hydroxydeoxyguanosine (8-OHdG) expression in the muscles and thiobarbituric acid reactive substance (TBARS) in sera to evaluate oxidative stress. Immunohistochemical detection of peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC1-α), mitochondrial transcription factor A (Tfam), and apoptosis were performed in the muscle tissue. RESULTS The mtDNA copy number was highest in muscle tissue, followed by blood vessel tissue, and lowest in leucocytes in both the diabetic and control subjects. The diabetic patients had less mtDNA content in the muscle than the controls (2.86±0.33 vs. 3.20±0.14, P=0.025), but more mtDNA content in the leucocytes (2.25±0.26 vs. 1.98±0.06, P=0.04). In both groups, there was a positive correlation between muscle tissue mtDNA content and the expression of 8-OHdG. Patients with T2DM had significantly increased 8-OHdG and TUNEL labeling index and non-significant increases in the expression of PGC1-α and Tfam. CONCLUSION Oxidative stress stimulates mitochondrial biogenesis but induces a greater degree of apoptosis in diabetic patients, resulting in a decrease in muscle tissue mtDNA content.
Collapse
Affiliation(s)
- Ching-Jung Hsieh
- Department of Internal Medicine, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Wang Q, Frolova AI, Purcell S, Adastra K, Schoeller E, Chi MM, Schedl T, Moley KH. Mitochondrial dysfunction and apoptosis in cumulus cells of type I diabetic mice. PLoS One 2010; 5:e15901. [PMID: 21209947 PMCID: PMC3011018 DOI: 10.1371/journal.pone.0015901] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Accepted: 11/30/2010] [Indexed: 12/23/2022] Open
Abstract
Impaired oocyte quality has been demonstrated in diabetic mice; however, the potential pathways by which maternal diabetes exerts its effects on the oocyte are poorly understood. Cumulus cells are in direct contact with the oocyte via gap junctions and provide essential nutrients to support oocyte development. In this study, we investigated the effects of maternal diabetes on the mitochondrial status in cumulus cells. We found an increased frequency of fragmented mitochondria, a decreased transmembrane potential and an aggregated distribution of mitochondria in cumulus cells from diabetic mice. Furthermore, while mitochondrial biogenesis in cumulus cells was induced by maternal diabetes, their metabolic function was disrupted as evidenced by lower ATP and citrate levels. Moreover, we present evidence suggesting that the mitochondrial impairments induced by maternal diabetes, at least in part, lead to cumulus cell apoptosis through the release of cytochrome c. Together the deleterious effects on cumulus cells may disrupt trophic and signaling interactions with the oocyte, contributing to oocyte incompetence and thus poor pregnancy outcomes in diabetic females.
Collapse
Affiliation(s)
- Qiang Wang
- Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Antonina I. Frolova
- Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Scott Purcell
- Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Katie Adastra
- Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Erica Schoeller
- Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Maggie M. Chi
- Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Tim Schedl
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Kelle H. Moley
- Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail:
| |
Collapse
|
47
|
Negre-Salvayre A, Auge N, Ayala V, Basaga H, Boada J, Brenke R, Chapple S, Cohen G, Feher J, Grune T, Lengyel G, Mann GE, Pamplona R, Poli G, Portero-Otin M, Riahi Y, Salvayre R, Sasson S, Serrano J, Shamni O, Siems W, Siow RCM, Wiswedel I, Zarkovic K, Zarkovic N. Pathological aspects of lipid peroxidation. Free Radic Res 2010; 44:1125-71. [PMID: 20836660 DOI: 10.3109/10715762.2010.498478] [Citation(s) in RCA: 480] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Lipid peroxidation (LPO) product accumulation in human tissues is a major cause of tissular and cellular dysfunction that plays a major role in ageing and most age-related and oxidative stress-related diseases. The current evidence for the implication of LPO in pathological processes is discussed in this review. New data and literature review are provided evaluating the role of LPO in the pathophysiology of ageing and classically oxidative stress-linked diseases, such as neurodegenerative diseases, diabetes and atherosclerosis (the main cause of cardiovascular complications). Striking evidences implicating LPO in foetal vascular dysfunction occurring in pre-eclampsia, in renal and liver diseases, as well as their role as cause and consequence to cancer development are addressed.
Collapse
|
48
|
Reiling E, Ling C, Uitterlinden AG, Van't Riet E, Welschen LMC, Ladenvall C, Almgren P, Lyssenko V, Nijpels G, van Hove EC, Maassen JA, de Geus EJC, Boomsma DI, Dekker JM, Groop L, Willemsen G, 't Hart LM. The association of mitochondrial content with prevalent and incident type 2 diabetes. J Clin Endocrinol Metab 2010; 95:1909-15. [PMID: 20150578 DOI: 10.1210/jc.2009-1775] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
CONTEXT It has been shown that mitochondrial DNA (mtDNA) content is associated with type 2 diabetes (T2D) and related traits. However, empirical data, often based on small samples, did not confirm this observation in all studies. Therefore, the role of mtDNA content in T2D remains elusive. OBJECTIVE In this study, we assessed the heritability of mtDNA content in buccal cells and analyzed the association of mtDNA content in blood with prevalent and incident T2D. DESIGN AND SETTING mtDNA content from cells from buccal and blood samples was assessed using a real-time PCR-based assay. Heritability of mtDNA content was estimated in 391 twins from the Netherlands Twin Register. The association with prevalent T2D was tested in a case control study from The Netherlands (n = 329). Incident T2D was analyzed using prospective samples from Finland (n = 444) and The Netherlands (n = 238). MAIN OUTCOME MEASURES We measured the heritability of mtDNA content and the association of mtDNA content in blood with prevalent and incident T2D. RESULTS A heritability of mtDNA content of 35% (19-48%) was estimated in the twin families. We did not observe evidence of an association between mtDNA content and prevalent or incident T2D and related traits. Furthermore, we observed a decline in mtDNA content with increasing age that was male specific (P = 0.001). CONCLUSION In this study, we show that mtDNA content has a heritability of 35% in Dutch twins. There is no association between mtDNA content in blood and prevalent or incident T2D and related traits in our study samples.
Collapse
Affiliation(s)
- Erwin Reiling
- Leiden University Medical Center, Department of Molecular Cell Biology, P.O. Box 9600, 2300 RC Leiden, The Netherlands
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
49
|
Wang PW, Lin TK, Weng SW, Liou CW. Mitochondrial DNA variants in the pathogenesis of type 2 diabetes - relevance of asian population studies. Rev Diabet Stud 2009; 6:237-46. [PMID: 20043036 DOI: 10.1900/rds.2009.6.237] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Mitochondrial dysfunction involves defective insulin secretion by pancreatic beta-cells, and insulin resistance in insulin-sensitive tissues such as muscle and adipose tissue. Mitochondria are recognized as the most important cellular source of energy, and the major generator of intracellular reactive oxygen species (ROS). Intracellular antioxidative systems have been developed to cope with increased oxidative damage. In case of minor oxidative stress, the cells may increase the number of mitochondria to produce more energy. A mechanism called mitochondrial biogenesis, involving several transcription factors and regulators, controls the quantity of mitochondria. When oxidative damage is advanced beyond the repair capacity of antioxidative systems, then oxidative stress can lead to cell death. Therefore, this organelle is central to cell life or death. Available evidence increasingly shows genetic linkage between mitochondrial DNA (mtDNA) alterations and type 2 diabetes (T2D). Based on previous studies, the mtDNA 16189 variant is associated with metabolic syndrome, higher fasting insulin concentration, insulin resistance index and lacunar cerebral infarction. These data support the involvement of mitochondrial genetic variation in the pathogenesis of T2D. Importantly, phylogeographic studies of the human mtDNAs have revealed that the human mtDNA tree is rooted in Africa and radiates into different geographic regions and can be grouped as haplogroups. The Asian populations carry very different mtDNA haplogroups as compared to European populations. Therefore, it is critically important to determine the role of mtDNA polymorphisms in T2D.
Collapse
Affiliation(s)
- Pei-Wen Wang
- Department of Internal Medicine, Chang Gung University College of Medicine, Chang Gung Memorial Hospital, Kaohsiung Medical Center, Kaohsiung, Taiwan 83305
| | | | | | | |
Collapse
|
50
|
Mitochondrial dysfunction and metabolic syndrome-looking for environmental factors. Biochim Biophys Acta Gen Subj 2009; 1800:282-9. [PMID: 19914351 DOI: 10.1016/j.bbagen.2009.11.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Revised: 10/28/2009] [Accepted: 11/06/2009] [Indexed: 01/06/2023]
Abstract
The centerpiece of the pathophysiologic mechanism of metabolic syndrome is insulin resistance. Recently, it is becoming evident that mitochondrial dysfunction is closely related to insulin resistance and metabolic syndrome. The underlying mechanism of mitochondrial dysfunction is very complex, which includes genetic factors from both nuclear and mitochondrial genome and numerous environmental factors. Several mitochondrial DNA polymorphisms are associated with the components of metabolic syndrome. Numerous chemicals and drugs may cause mitochondrial dysfunction and insulin resistance. Notably, it was recently reported that serum levels of several mitochondrial toxins, such as persistent organic pollutants are associated with metabolic syndrome, which necessitates further investigation to reveal its precise mechanism. Given that the health impact of metabolic syndrome is tremendous, it is necessary to develop therapeutic modalities to correct mitochondrial dysfunction or at least to halt its aggravation. In this regard, exercise can improve both mitochondrial function and insulin sensitivity, and some pharmaceutical agents were reported to improve mitochondrial function. However, further studies are warranted to find more effective therapeutic strategies to treat mitochondrial dysfunction. By doing so, we can also shed light on the path of research for other diseases related to mitochondrial dysfunction.
Collapse
|