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Genetically modified mice for research on human diseases: A triumph for Biotechnology or a work in progress? THE EUROBIOTECH JOURNAL 2022. [DOI: 10.2478/ebtj-2022-0008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/06/2022] Open
Abstract
Abstract
Genetically modified mice are engineered as models for human diseases. These mouse models include inbred strains, mutants, gene knockouts, gene knockins, and ‘humanized’ mice. Each mouse model is engineered to mimic a specific disease based on a theory of the genetic basis of that disease. For example, to test the amyloid theory of Alzheimer’s disease, mice with amyloid precursor protein genes are engineered, and to test the tau theory, mice with tau genes are engineered. This paper discusses the importance of mouse models in basic research, drug discovery, and translational research, and examines the question of how to define the “best” mouse model of a disease. The critiques of animal models and the caveats in translating the results from animal models to the treatment of human disease are discussed. Since many diseases are heritable, multigenic, age-related and experience-dependent, resulting from multiple gene-gene and gene-environment interactions, it will be essential to develop mouse models that reflect these genetic, epigenetic and environmental factors from a developmental perspective. Such models would provide further insight into disease emergence, progression and the ability to model two-hit and multi-hit theories of disease. The summary examines the biotechnology for creating genetically modified mice which reflect these factors and how they might be used to discover new treatments for complex human diseases such as cancers, neurodevelopmental and neurodegenerative diseases.
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Omics Insights into Animal Resilience and Stress Factors. Animals (Basel) 2020; 11:ani11010047. [PMID: 33383711 PMCID: PMC7824193 DOI: 10.3390/ani11010047] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 12/26/2022] Open
Abstract
Resilience is conceived as a dynamic developmental process involving the achievement of positive adaptation within the context of significant adversity. Resilience is not a unique ability but rather a set of capacities of a system put in place to absorb a disturbance and to reorganize while trying to retain the same function, structure, and identity. This review describes the characteristics and the molecular mechanisms of resilience to understand the core elements of resilience and its indicators. The objectives of this review are: (1) to define some of the leading environmental stressors and clarify the mechanism of vulnerability or resilience outcomes; (2) to clarify some of the prominent epigenetic modulations mediating resilience or vulnerability as a stress response; (3) to highlight the neural mechanisms related to stress resilience since the central nervous system is a highly dynamic structure characterized by an everlasting plasticity feature, which therefore has the opportunity to modify resilience. The review aims to introduce the reader to the concept of resilience seen as an ability acquired in life and not only inherited from birth.
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Matheson K, Asokumar A, Anisman H. Resilience: Safety in the Aftermath of Traumatic Stressor Experiences. Front Behav Neurosci 2020; 14:596919. [PMID: 33408619 PMCID: PMC7779406 DOI: 10.3389/fnbeh.2020.596919] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 11/30/2020] [Indexed: 12/14/2022] Open
Abstract
The relationship between adverse experiences and the emergence of pathology has often focused on characteristics of the stressor or of the individual (stressor appraisals, coping strategies). These features are thought to influence multiple biological processes that favor the development of mental and physical illnesses. Less often has attention focused on the aftermath of traumatic experiences, and the importance of safety and reassurance that is necessary for longer-term well-being. In some cases (e.g., post-traumatic stress disorder) this may be reflected by a failure of fear extinction, whereas in other instances (e.g., historical trauma), the uncertainty about the future might foster continued anxiety. In essence, the question becomes one of how individuals attain feelings of safety when it is fully understood that the world is not necessarily a safe place, uncertainties abound, and feelings of agency are often illusory. We consider how individuals acquire resilience in the aftermath of traumatic and chronic stressors. In this respect, we review characteristics of stressors that may trigger particular biological and behavioral coping responses, as well as factors that undermine their efficacy. To this end, we explore stressor dynamics and social processes that foster resilience in response to specific traumatic, chronic, and uncontrollable stressor contexts (intimate partner abuse; refugee migration; collective historical trauma). We point to resilience factors that may comprise neurobiological changes, such as those related to various stressor-provoked hormones, neurotrophins, inflammatory immune, microbial, and epigenetic processes. These behavioral and biological stress responses may influence, and be influenced by, feelings of safety that come about through relationships with others, spiritual and place-based connections.
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Affiliation(s)
- Kimberly Matheson
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada.,The Royal Ottawa's Institute of Mental Health Research, Ottawa, ON, Canada
| | - Ajani Asokumar
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada
| | - Hymie Anisman
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada.,The Royal Ottawa's Institute of Mental Health Research, Ottawa, ON, Canada
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Yousuf FA, Kazmi K, Iqbal J, Ahmed N, Iqbal MP. Higher DNA methylation of ABO gene promoter is associated with acute myocardial infarction in a hospital-based population in Karachi. Pak J Med Sci 2020; 36:505-510. [PMID: 32292461 PMCID: PMC7150418 DOI: 10.12669/pjms.36.3.1406] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Objective To find out if there is any relationship of methylation status of ABO gene promoter with the risk of acute myocardial infarction (AMI) in a hospital-based Pakistani population in Karachi, Pakistan. Methods A case control study comprising of 39 adult AMI patients (both males and females; age range 30-70 years) and 39 normal healthy controls (both males and females and similar age range) nested in a large study (to see the relationship of ABO genotypes with AMI) was designed to investigate the methylation status of ABO gene promoter and its association with AMI. The study was carried out at the Aga Khan University, Karachi during July 2018 to June 2019. DNA isolated from samples of AMI patients and normal healthy controls were converted into bisulphite DNA using a kit method. Methylation specific polymerase chain reaction was carried out to determine the methylation status of ABO gene promoter in both cases and controls. Logistic regression was used to find out any association between increased methylation status of ABO gene promoter and risk of AMI. Results A significantly higher percentage of DNA methylation of the ABO gene promoter was observed in AMI patients as compared to normal healthy controls (82.1% vs. 35.9%; p value <0.001). This higher methylation status of ABO gene promoter was associated with AMI and the odds of AMI in this population were more than 6-fold in subjects with methylated gene promoter compared to those with unmethylated gene promoter after adjusting with age and waist circumference [AOR (95% CI) = 6.27 (1.76-22.3); p value = 0.005]. Conclusion The ABO gene promoter's hypermethylation appears to be increasing the risk of AMI in a hospital-based Pakistani population in Karachi, Pakistan.
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Affiliation(s)
- Farzana Abubakar Yousuf
- Farzana Abubakar Yousuf, Department of Biological and Biomedical Sciences, Aga Khan University, Karachi 74800, Pakistan
| | - Khawar Kazmi
- Khawar Kazmi, National Institute of Cardiovascular Diseases, Karachi, Pakistan
| | - Junaid Iqbal
- Junaid Iqbal, Department of Biological and Biomedical Sciences, Aga Khan University, Karachi 74800, Pakistan
| | - Nikhat Ahmed
- Nikhat Ahmed, Department of Biochemistry, University of Karachi, Karachi, Pakistan
| | - Mohammad Perwaiz Iqbal
- Mohammad Perwaiz Iqbal, Pakistan Academy of Sciences, Islamabad - Pakistan. Department of Biological and Biomedical Sciences, Aga Khan University, Karachi 74800, Pakistan
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Early Programming of Adult Systemic Essential Hypertension. Int J Mol Sci 2020; 21:ijms21041203. [PMID: 32054074 PMCID: PMC7072742 DOI: 10.3390/ijms21041203] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/27/2020] [Accepted: 02/10/2020] [Indexed: 12/13/2022] Open
Abstract
Cardiovascular diseases are being included in the study of developmental origins of health and disease (DOHaD) and essential systemic hypertension has also been added to this field. Epigenetic modifications are one of the main mechanisms leading to early programming of disease. Different environmental factors occurring during critical windows in the early stages of life may leave epigenetic cues, which may be involved in the programming of hypertension when individuals reach adulthood. Such environmental factors include pre-term birth, low weight at birth, altered programming of different organs such as the blood vessels and the kidney, and living in disadvantageous conditions in the programming of hypertension. Mechanisms behind these factors that impact on the programming include undernutrition, oxidative stress, inflammation, emotional stress, and changes in the microbiota. These factors and their underlying causes acting at the vascular level will be discussed in this paper. We also explore the establishment of epigenetic cues that may lead to hypertension at the vascular level such as DNA methylation, histone modifications (methylation and acetylation), and the role of microRNAs in the endothelial cells and blood vessel smooth muscle which participate in hypertension. Since epigenetic changes are reversible, the knowledge of this type of markers could be useful in the field of prevention, diagnosis or epigenetic drugs as a therapeutic approach to hypertension.
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Zhang P, Li T, Liu YQ, Zhang H, Xue SM, Li G, Cheng HYM, Cao JM. Contribution of DNA methylation in chronic stress-induced cardiac remodeling and arrhythmias in mice. FASEB J 2019; 33:12240-12252. [PMID: 31431066 DOI: 10.1096/fj.201900100r] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
It is recognized that stress can induce cardiac dysfunction, but the underlying mechanisms are not well understood. The present study aimed to test the hypothesis that chronic negative stress leads to alterations in DNA methylation of certain cardiac genes, which in turn contribute to pathologic remodeling of the heart. We found that mice that were exposed to chronic restraint stress (CRS) for 4 wk exhibited cardiac remodeling toward heart failure, as characterized by ventricular chamber dilatation, wall thinning, and decreased contractility. CRS also induced cardiac arrhythmias, including intermittent sinus tachycardia and bradycardia, frequent premature ventricular contraction, and sporadic atrioventricular conduction block. Circulating levels of stress hormones were elevated, and the cardiac expression of tyrosine hydroxylase, a marker of sympathetic innervation, was increased in CRS mice. Using reduced representation bisulfite sequencing, we found that although CRS did not lead to global changes in DNA methylation in the murine heart, it nevertheless altered methylation at specific genes that are associated with the dilated cardiomyopathy (DCM) (e.g., desmin) and adrenergic signaling of cardiomyocytes (ASPC) (e.g., adrenergic receptor-α1) pathways. We conclude that CRS induces cardiac remodeling and arrhythmias, potentially through altered methylation of myocardial genes associated with the DCM and ASPC pathways.-Zhang, P., Li, T., Liu, Y.-Q., Zhang, H., Xue, S.-M., Li, G., Cheng, H.-Y.M., Cao, J.-M. Contribution of DNA methylation in chronic stress-induced cardiac remodeling and arrhythmias in mice.
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Affiliation(s)
- Peng Zhang
- Institute of Cardiovascular Research, Key Laboratory of Medical Electrophysiology, Ministry of Education-Medical Electrophysiological Key Laboratory of Sichuan Province, Southwest Medical University, Luzhou, China.,Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease of Sichuan Province, Southwest Medical University, Luzhou, China
| | - Tao Li
- Institute of Cardiovascular Research, Key Laboratory of Medical Electrophysiology, Ministry of Education-Medical Electrophysiological Key Laboratory of Sichuan Province, Southwest Medical University, Luzhou, China.,Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease of Sichuan Province, Southwest Medical University, Luzhou, China
| | - Ya-Qin Liu
- Institute of Cardiovascular Research, Key Laboratory of Medical Electrophysiology, Ministry of Education-Medical Electrophysiological Key Laboratory of Sichuan Province, Southwest Medical University, Luzhou, China.,Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease of Sichuan Province, Southwest Medical University, Luzhou, China
| | - Hao Zhang
- Institute of Cardiovascular Research, Key Laboratory of Medical Electrophysiology, Ministry of Education-Medical Electrophysiological Key Laboratory of Sichuan Province, Southwest Medical University, Luzhou, China
| | - Si-Meng Xue
- Institute of Cardiovascular Research, Key Laboratory of Medical Electrophysiology, Ministry of Education-Medical Electrophysiological Key Laboratory of Sichuan Province, Southwest Medical University, Luzhou, China.,Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease of Sichuan Province, Southwest Medical University, Luzhou, China
| | - Guang Li
- Institute of Cardiovascular Research, Key Laboratory of Medical Electrophysiology, Ministry of Education-Medical Electrophysiological Key Laboratory of Sichuan Province, Southwest Medical University, Luzhou, China
| | - Hai-Ying Mary Cheng
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Ji-Min Cao
- Institute of Cardiovascular Research, Key Laboratory of Medical Electrophysiology, Ministry of Education-Medical Electrophysiological Key Laboratory of Sichuan Province, Southwest Medical University, Luzhou, China.,Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease of Sichuan Province, Southwest Medical University, Luzhou, China.,Key Laboratory of Cellular Physiology, Ministry of Education, Department of Physiology, Shanxi Medical University, Taiyuan, China
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Timothy A, Benegal V, Shankarappa B, Saxena S, Jain S, Purushottam M. Influence of early adversity on cortisol reactivity, SLC6A4 methylation and externalizing behavior in children of alcoholics. Prog Neuropsychopharmacol Biol Psychiatry 2019; 94:109649. [PMID: 31082414 DOI: 10.1016/j.pnpbp.2019.109649] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 04/29/2019] [Accepted: 05/09/2019] [Indexed: 12/12/2022]
Abstract
BACKGROUND Children of parents with alcoholism face considerable stress, and often have externalizing behaviors. Early adversity is known to affect DNA methylation and the functioning of the HPA axis. We investigated the association of early adversity with cortisol reactivity, 5HTTLPR genotype, site specific DNA methylation in the SLC6A4 gene and externalizing behavior in children of alcoholics (COA), and a matched sample of control children. METHODS We examined children of alcoholics (N = 50) and age matched control children (N = 50) for exposure to early adversity (both prenatal and postnatal), assessed their salivary cortisol reactivity and evaluated their levels of emotional and behavioral difficulty in terms of externalizing and internalizing behavior. Site-specific DNA methylation at a previously characterized SLC6A4 region was determined in salivary DNA using pyrosequencing. The 5HTTLPR region of the SLC6A4 gene was also genotyped. RESULTS COA had significantly higher experience of early adversity than control children. Cortisol reactivity was reduced in COA, and negatively correlated with early adversity. Both early adversity and cortisol reactivity correlated with externalizing behavior. SLC6A4 methylation was higher in COA, and correlated with early adversity. SLC6A4 genotype did not show association with any of the variables. CONCLUSION Our study provides further evidence that early adversity is associated with blunted cortisol reactivity, increased site-specific CpG DNA methylation at the SLC6A4 gene, and high externalizing behavior.
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Affiliation(s)
- Anurag Timothy
- Centre for Addiction Medicine, National Institute of Mental Health and Neurosciences, Bangalore 560029, India; Department of Psychiatry, Base Hospital Delhi Cantt, New Delhi 110010, India
| | - Vivek Benegal
- Centre for Addiction Medicine, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
| | - Bhagyalakshmi Shankarappa
- Molecular Genetics Lab, Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore 560029, India; St Johns Medical College Hospital, Bangalore, India
| | - Sachin Saxena
- Department of Psychiatry, Base Hospital Delhi Cantt, New Delhi 110010, India
| | - Sanjeev Jain
- Molecular Genetics Lab, Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
| | - Meera Purushottam
- Molecular Genetics Lab, Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore 560029, India.
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Albott CS, Forbes MK, Anker JJ. Association of Childhood Adversity With Differential Susceptibility of Transdiagnostic Psychopathology to Environmental Stress in Adulthood. JAMA Netw Open 2018; 1:e185354. [PMID: 30646399 PMCID: PMC6324405 DOI: 10.1001/jamanetworkopen.2018.5354] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
IMPORTANCE Multivariable comorbidity research indicates that childhood adversity increases the risk for the development of common mental disorders. This risk is explained by underlying internalizing and externalizing transdiagnostic constructs that are amplified by environmental stressors. The differential susceptibility model suggests that this interaction of risk and environment is bidirectional: at-risk individuals will have worse outcomes in high-stress environments but better outcomes in in low-stress environments. OBJECTIVE To test the differential susceptibility model by examining how a history of adverse childhood experiences moderates the association between life stress and transdiagnostic psychopathology. DESIGN, SETTING, AND PARTICIPANTS Data came from the US National Epidemiological Survey on Alcohol and Related Conditions (NESARC), a population-based observational longitudinal survey administered to adults (≥18 years of age). Participants completed the survey at wave 1 (from 2001 through 2002) and wave 2 (from 2004 through 2005). Responses from 34 458 participants were used for the analyses from March 3, 2017, through October 8, 2018. MAIN OUTCOMES AND MEASURES Latent variables for internalizing-fear, internalizing-distress, externalizing, and general psychopathology were created to represent continuous levels of psychopathology in each wave. Latent variables were also created to represent continuous levels of life stress at each wave. Level of childhood adversity was characterized based on the number of types of childhood adversity experienced (no [0 types], low [1-2 types], and high [≥3 types] exposure). Analyses examined how the interaction between level of childhood adversity and adult life stress was associated with change in adult transdiagnostic psychopathology factors. RESULTS Of the 34 458 participants included in the analysis (58.0% women and 42.0% men; mean [SD] age, 46.0 [17.4] years at wave 1 and 49.0 [17.3] years at wave 2), 40.5% had no adverse childhood experiences, 34.6% had 1 to 2, and 24.9% had 3 or more. At wave 1, 61.5% of the sample endorsed at least 1 stressful life event and 27.2% met criteria for at least 1 mental disorder; at wave 2, these figures were 64.7% and 29.7%, respectively. Childhood adversity moderated the association between changes in adult life stress and changes in all transdiagnostic psychopathology factors. Specifically, higher levels of childhood adversity had a stronger association between adult life stress and adult transdiagnostic psychopathology factors. Further, significant differences between childhood adversity groups occurred in the mean scores of all transdiagnostic psychopathology factors for both increases and decreases in life stress, providing preliminary evidence of differential susceptibility. CONCLUSIONS AND RELEVANCE Results provide empirical support for childhood adversity as a differential susceptibility factor engendering heightened functional and dysfunctional reactivity to later stress.
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Affiliation(s)
- C Sophia Albott
- Department of Psychiatry, University of Minnesota Medical School, Minneapolis
| | - Miriam K Forbes
- Department of Psychiatry, University of Minnesota Medical School, Minneapolis
- Centre for Emotional Health, Macquarie University, Sydney, Australia
| | - Justin J Anker
- Department of Psychiatry, University of Minnesota Medical School, Minneapolis
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Epigenetics of Neurodevelopmental Disorders Comes of Age with Roles in Clinical and Educational Applications. Int J Mol Sci 2018; 19:ijms19092720. [PMID: 30213026 PMCID: PMC6163238 DOI: 10.3390/ijms19092720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 09/08/2018] [Indexed: 11/16/2022] Open
Abstract
Epigenetics is a gene regulation mechanism that does not depend on genomic DNA sequences, but depends instead on chemical modifications of DNA and histone proteins. [...]
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Epigenetics of Subcellular Structure Functioning in the Origin of Risk or Resilience to Comorbidity of Neuropsychiatric and Cardiometabolic Disorders. Int J Mol Sci 2018; 19:ijms19051456. [PMID: 29757967 PMCID: PMC5983601 DOI: 10.3390/ijms19051456] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 05/04/2018] [Accepted: 05/09/2018] [Indexed: 12/31/2022] Open
Abstract
Mechanisms controlling mitochondrial function, protein folding in the endoplasmic reticulum (ER) and nuclear processes such as telomere length and DNA repair may be subject to epigenetic cues that relate the genomic expression and environmental exposures in early stages of life. They may also be involved in the comorbid appearance of cardiometabolic (CMD) and neuropsychiatric disorders (NPD) during adulthood. Mitochondrial function and protein folding in the endoplasmic reticulum are associated with oxidative stress and elevated intracellular calcium levels and may also underlie the vulnerability for comorbid CMD and NPD. Mitochondria provide key metabolites such as nicotinamide adenine dinucleotide (NAD+), ATP, α-ketoglutarate and acetyl coenzyme A that are required for many transcriptional and epigenetic processes. They are also a source of free radicals. On the other hand, epigenetic markers in nuclear DNA determine mitochondrial biogenesis. The ER is the subcellular organelle in which secretory proteins are folded. Many environmental factors stop the ability of cells to properly fold proteins and modify post-translationally secretory and transmembrane proteins leading to endoplasmic reticulum stress and oxidative stress. ER functioning may be epigenetically determined. Chronic ER stress is emerging as a key contributor to a growing list of human diseases, including CMD and NPD. Telomere loss causes chromosomal fusion, activation of the control of DNA damage-responses, unstable genome and altered stem cell function, which may underlie the comorbidity of CMD and NPD. The length of telomeres is related to oxidative stress and may be epigenetically programmed. Pathways involved in DNA repair may be epigenetically programmed and may contribute to diseases. In this paper, we describe subcellular mechanisms that are determined by epigenetic markers and their possible relation to the development of increased susceptibility to develop CMD and NPD.
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