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The potential role of environmental factors in modulating mitochondrial DNA epigenetic marks. VITAMINS AND HORMONES 2023; 122:107-145. [PMID: 36863791 DOI: 10.1016/bs.vh.2023.01.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Many studies implicate mitochondrial dysfunction in the development and progression of numerous chronic diseases. Mitochondria are responsible for most cellular energy production, and unlike other cytoplasmic organelles, mitochondria contain their own genome. Most research to date, through investigating mitochondrial DNA copy number, has focused on larger structural changes or alterations to the entire mitochondrial genome and their role in human disease. Using these methods, mitochondrial dysfunction has been linked to cancers, cardiovascular disease, and metabolic health. However, like the nuclear genome, the mitochondrial genome may experience epigenetic alterations, including DNA methylation that may partially explain some of the health effects of various exposures. Recently, there has been a movement to understand human health and disease within the context of the exposome, which aims to describe and quantify the entirety of all exposures people encounter throughout their lives. These include, among others, environmental pollutants, occupational exposures, heavy metals, and lifestyle and behavioral factors. In this chapter, we summarize the current research on mitochondria and human health, provide an overview of the current knowledge on mitochondrial epigenetics, and describe the experimental and epidemiologic studies that have investigated particular exposures and their relationships with mitochondrial epigenetic modifications. We conclude the chapter with suggestions for future directions in epidemiologic and experimental research that is needed to advance the growing field of mitochondrial epigenetics.
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Low HC, Chilian WM, Ratnam W, Karupaiah T, Md Noh MF, Mansor F, Ng ZX, Pung YF. Changes in Mitochondrial Epigenome in Type 2 Diabetes Mellitus. Br J Biomed Sci 2023; 80:10884. [PMID: 36866104 PMCID: PMC9970885 DOI: 10.3389/bjbs.2023.10884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 01/30/2023] [Indexed: 02/16/2023]
Abstract
Type 2 Diabetes Mellitus is a major chronic metabolic disorder in public health. Due to mitochondria's indispensable role in the body, its dysfunction has been implicated in the development and progression of multiple diseases, including Type 2 Diabetes mellitus. Thus, factors that can regulate mitochondrial function, like mtDNA methylation, are of significant interest in managing T2DM. In this paper, the overview of epigenetics and the mechanism of nuclear and mitochondrial DNA methylation were briefly discussed, followed by other mitochondrial epigenetics. Subsequently, the association between mtDNA methylation with T2DM and the challenges of mtDNA methylation studies were also reviewed. This review will aid in understanding the impact of mtDNA methylation on T2DM and future advancements in T2DM treatment.
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Affiliation(s)
- Hui Ching Low
- Division of Biomedical Science, Faculty of Science and Engineering, University of Nottingham Malaysia, Semenyih, Selangor, Malaysia
| | - William M. Chilian
- Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown Township, OH, United States
| | - Wickneswari Ratnam
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Tilakavati Karupaiah
- School of Biosciences, Faculty of Health and Medical Sciences, Taylor’s University Lakeside Campus, Subang Jaya, Selangor, Malaysia
| | - Mohd Fairulnizal Md Noh
- Nutrition, Metabolism and Cardiovascular Research Centre, Institute for Medical Research, National Institute of Health, Setia Alam, Shah Alam, Malaysia
| | - Fazliana Mansor
- Nutrition, Metabolism and Cardiovascular Research Centre, Institute for Medical Research, National Institute of Health, Setia Alam, Shah Alam, Malaysia
| | - Zhi Xiang Ng
- School of Biosciences, Faculty of Science and Engineering, University of Nottingham Malaysia, Semenyih, Selangor, Malaysia
| | - Yuh Fen Pung
- Division of Biomedical Science, Faculty of Science and Engineering, University of Nottingham Malaysia, Semenyih, Selangor, Malaysia,*Correspondence: Yuh Fen Pung,
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Andrawus M, Sharvit L, Atzmon G. Epigenetics and Pregnancy: Conditional Snapshot or Rolling Event. Int J Mol Sci 2022; 23:12698. [PMID: 36293556 PMCID: PMC9603966 DOI: 10.3390/ijms232012698] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/12/2022] [Accepted: 10/19/2022] [Indexed: 11/17/2022] Open
Abstract
Epigenetics modification such as DNA methylation can affect maternal health during the gestation period. Furthermore, pregnancy can drive a range of physiological and molecular changes that have the potential to contribute to pathological conditions. Pregnancy-related risk factors include multiple environmental, behavioral, and hereditary factors that can impact maternal DNA methylation with long-lasting consequences. Identification of the epigenetic patterns linked to poor pregnancy outcomes is crucial since changes in DNA methylation patterns can have long-term effects. In this review, we provide an overview of the epigenetic changes that influence pregnancy-related molecular programming such as gestational diabetes, immune response, and pre-eclampsia, in an effort to close the gap in current understanding regarding interactions between the environment, the genetics of the fetus, and the pregnant woman.
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Affiliation(s)
| | | | - Gil Atzmon
- Department of Human Biology, University of Haifa, Haifa 3498838, Israel
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Atilano SR, Abedi S, Ianopol NV, Singh MK, Norman JL, Malik D, Falatoonzadeh P, Chwa M, Nesburn AB, Kuppermann BD, Kenney MC. Differential Epigenetic Status and Responses to Stressors between Retinal Cybrids Cells with African versus European Mitochondrial DNA: Insights into Disease Susceptibilities. Cells 2022; 11:2655. [PMID: 36078063 PMCID: PMC9454894 DOI: 10.3390/cells11172655] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 08/19/2022] [Accepted: 08/23/2022] [Indexed: 11/16/2022] Open
Abstract
Mitochondrial (mt) DNA can be classified into haplogroups, which represent populations with different geographic origins. Individuals of maternal African backgrounds (L haplogroup) are more prone to develop specific diseases compared those with maternal European-H haplogroups. Using a cybrid model, effects of amyloid-β (Amyβ), sub-lethal ultraviolet (UV) radiation, and 5-Aza-2'-deoxycytidine (5-aza-dC), a methylation inhibitor, were investigated. Amyβ treatment decreased cell metabolism and increased levels of reactive oxygen species in European-H and African-L cybrids, but lower mitochondrial membrane potential (ΔΨM) was found only in African-L cybrids. Sub-lethal UV radiation induced higher expression levels of CFH, EFEMP1, BBC3, and BCL2L13 in European-H cybrids compared to African-L cybrids. With respect to epigenetic status, the African-L cybrids had (a) 4.7-fold higher total global methylation levels (p = 0.005); (b) lower expression patterns for DNMT3B; and (c) elevated levels for HIST1H3F. The European-H and African-L cybrids showed different transcription levels for CFH, EFEMP1, CXCL1, CXCL8, USP25, and VEGF after treatment with 5-aza-dC. In conclusion, compared to European-H haplogroup cybrids, the African-L cybrids have different (i) responses to exogenous stressors (Amyβ and UV radiation), (ii) epigenetic status, and (iii) modulation profiles of methylation-mediated downstream complement, inflammation, and angiogenesis genes, commonly associated with various human diseases.
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Affiliation(s)
- Shari R. Atilano
- Gavin Herbert Eye Institute, Ophthalmology Research Laboratory, University of California Irvine, Hewitt Hall, Room 2028, 843 Health Science Rd., Irvine, CA 92697, USA
| | - Sina Abedi
- Gavin Herbert Eye Institute, Ophthalmology Research Laboratory, University of California Irvine, Hewitt Hall, Room 2028, 843 Health Science Rd., Irvine, CA 92697, USA
| | - Narcisa V. Ianopol
- Gavin Herbert Eye Institute, Ophthalmology Research Laboratory, University of California Irvine, Hewitt Hall, Room 2028, 843 Health Science Rd., Irvine, CA 92697, USA
| | - Mithalesh K. Singh
- Gavin Herbert Eye Institute, Ophthalmology Research Laboratory, University of California Irvine, Hewitt Hall, Room 2028, 843 Health Science Rd., Irvine, CA 92697, USA
| | - J Lucas Norman
- Gavin Herbert Eye Institute, Ophthalmology Research Laboratory, University of California Irvine, Hewitt Hall, Room 2028, 843 Health Science Rd., Irvine, CA 92697, USA
| | - Deepika Malik
- Gavin Herbert Eye Institute, Ophthalmology Research Laboratory, University of California Irvine, Hewitt Hall, Room 2028, 843 Health Science Rd., Irvine, CA 92697, USA
| | - Payam Falatoonzadeh
- Gavin Herbert Eye Institute, Ophthalmology Research Laboratory, University of California Irvine, Hewitt Hall, Room 2028, 843 Health Science Rd., Irvine, CA 92697, USA
| | - Marilyn Chwa
- Gavin Herbert Eye Institute, Ophthalmology Research Laboratory, University of California Irvine, Hewitt Hall, Room 2028, 843 Health Science Rd., Irvine, CA 92697, USA
| | - Anthony B. Nesburn
- Gavin Herbert Eye Institute, Ophthalmology Research Laboratory, University of California Irvine, Hewitt Hall, Room 2028, 843 Health Science Rd., Irvine, CA 92697, USA
- Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Baruch D. Kuppermann
- Gavin Herbert Eye Institute, Ophthalmology Research Laboratory, University of California Irvine, Hewitt Hall, Room 2028, 843 Health Science Rd., Irvine, CA 92697, USA
| | - M. Cristina Kenney
- Gavin Herbert Eye Institute, Ophthalmology Research Laboratory, University of California Irvine, Hewitt Hall, Room 2028, 843 Health Science Rd., Irvine, CA 92697, USA
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA 92697, USA
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Zhou Z, Goodrich JM, Strakovsky RS. Mitochondrial Epigenetics and Environmental Health: Making a Case for Endocrine Disrupting Chemicals. Toxicol Sci 2021; 178:16-25. [PMID: 32777053 DOI: 10.1093/toxsci/kfaa129] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Recent studies implicate mitochondrial dysfunction in the development and progression of numerous chronic diseases, which may be partially due to modifications in mitochondrial DNA (mtDNA). There is also mounting evidence that epigenetic modifications to mtDNA may be an additional layer of regulation that controls mitochondrial biogenesis and function. Several environmental factors (eg, smoking, air pollution) have been associated with altered mtDNA methylation in a handful of mechanistic studies and in observational human studies. However, little is understood about other environmental contaminants that induce mtDNA epigenetic changes. Numerous environmental toxicants are classified as endocrine disrupting chemicals (EDCs). Beyond their actions on hormonal pathways, EDC exposure is associated with elevated oxidative stress, which may occur through or result in mitochondrial dysfunction. Although only a few studies have assessed the impacts of EDCs on mtDNA methylation, the current review provides reasons to consider mtDNA epigenetic disruption as a mechanism of action of EDCs and reviews potential limitations related to currently available evidence. First, there is sufficient evidence that EDCs (including bisphenols and phthalates) directly target mitochondrial function, and more direct evidence is needed to connect this to mtDNA methylation. Second, these and other EDCs are potent modulators of nuclear DNA epigenetics, including DNA methylation and histone modifications. Finally, EDCs have been shown to disrupt several modulators of mtDNA methylation, including DNA methyltransferases and the mitochondrial transcription factor A/nuclear respiratory factor 1 pathway. Taken together, these studies highlight the need for future research evaluating mtDNA epigenetic disruption by EDCs and to detail specific mechanisms responsible for such disruptions.
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Affiliation(s)
- Zheng Zhou
- Department of Animal Sciences, Michigan State University, East Lansing, Michigan 48824
| | - Jaclyn M Goodrich
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, Michigan 48109
| | - Rita S Strakovsky
- Department of Food Science and Human Nutrition.,Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824
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Ramasamy D, Deva Magendhra Rao AK, Rajkumar T, Mani S. Non-CpG methylation-a key epigenetic modification in cancer. Brief Funct Genomics 2021; 20:304-311. [PMID: 34318313 DOI: 10.1093/bfgp/elab035] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/28/2021] [Accepted: 07/02/2021] [Indexed: 12/17/2022] Open
Abstract
The methylation of cytosine residues that precede adenine/thymine or other cytosine nucleotides instead of guanine in DNA is known as non-CpG methylation. It is a pronounced epigenetic modification with a central role in gene regulation similar to CpG methylation. Due to technological limitations, the locus-specific role of non-CpG methylation was scarcely understood. At present, high-throughput analyses and improved enrichment methods can elucidate the role of genome-wide non-CpG methylation distributions. Although the functional basis of non-CpG methylation in regulating gene expression control is known, its role in cancer development is yet to be ascertained. This review sheds light on the possible mechanism of non-CpG methylation in embryos and developed tissues with a special focus on cancer development and progression. In particular, the maintenance and alteration of non-CpG methylation levels and the crucial factors that determine this level of non-CpG methylation and its functional role in cancer are discussed.
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Vos S, Nawrot TS, Martens DS, Byun HM, Janssen BG. Mitochondrial DNA methylation in placental tissue: a proof of concept study by means of prenatal environmental stressors. Epigenetics 2020; 16:121-131. [PMID: 32657220 PMCID: PMC7889149 DOI: 10.1080/15592294.2020.1790923] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
While previous studies have demonstrated that prenatal exposure to environmental stressors is associated with mitochondrial DNA (mtDNA) methylation, more recent investigations are questioning the accuracy of the methylation assessment and its biological relevance. In this study, we investigated placental mtDNA methylation while accounting for methodological issues such as nuclear contamination, bisulphite conversion, and PCR bias. From the ENVIRONAGE birth cohort, we selected three groups of participants (n = 20/group). One group with mothers who smoked during pregnancy (average 13.2 cig/day), one group with high air pollutant exposure (PM2.5: 16.0 ± 1.4 µg/m3, black carbon: 1.8 ± 0.3 µg/m3) and one control group (non-smokers, PM2.5: 10.6 ± 1.7 µg/m3, black carbon: 0.9 ± 0.1 µg/m3) with low air pollutant exposure. DNA methylation levels were quantified in two regions of the displacement loop control region (D-loop and LDLR2) by bisulphite pyrosequencing. Additionally, we measured DNA methylation on nuclear genes involved in mitochondrial maintenance (PINK1, DNA2, and POLG1) and assessed mtDNA content using qPCR. Absolute D-loop methylation levels were higher for mothers that smoked extensively (+0.36%, 95% CI: 0.06% to 0.66%), and for mothers that were highly exposed to air pollutants (+0.47%, 95% CI: 0.20% to 0.73%). The relevance of our findings is further supported, as D-loop methylation levels were correlated with placental mtDNA content (r = −0.40, p = 0.002) and associated with birth weight (−106.98 g, 95% CI: −209.60 g to −4.36 g for an IQR increase in D-loop methylation). Most notably, our data demonstrates relevant levels of mtDNA methylation in placenta tissue, with significant associations between prenatal exposure to environmental stressors and D-loop methylation.
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Affiliation(s)
- Stijn Vos
- Centre for Environmental Sciences, Hasselt University , Hasselt, Belgium
| | - Tim S Nawrot
- Centre for Environmental Sciences, Hasselt University , Hasselt, Belgium.,Department of Public Health & Primary Care, Occupational & Environmental Medicine, Leuven University , Leuven, Belgium
| | - Dries S Martens
- Centre for Environmental Sciences, Hasselt University , Hasselt, Belgium
| | - Hyang-Min Byun
- Population Health Sciences Institute, Newcastle University , Newcastle upon Tyne, UK
| | - Bram G Janssen
- Centre for Environmental Sciences, Hasselt University , Hasselt, Belgium
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