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Nonsynaptic plasticity model of long-term memory engrams

Cacha LA, Ali J, Rizvi ZH, Yupapin PP, Poznanski RR

J Integr Neurosci, 2017;16(4):493-509.
PMID: 28891529 DOI: 10.3233/JIN-170038

Using steady-state electrical properties of non-ohmic dendrite based on cable theory, we derive electrotonic potentials that do not change over time and are localized in space. We hypothesize that clusters of such stationary, local and permanent pulses are the electrical signatures of enduring memories which are imprinted through nonsynaptic plasticity, encoded through epigenetic mechanisms, and decoded through electrotonic processing. We further hypothesize how retrieval of an engram is made possible by integration of these permanently imprinted standing pulses in a neural circuit through neurotransmission in the extracellular space as part of conscious recall that acts as a guiding template in the reconsolidation of long-term memories through novelty characterized by uncertainty that arises when new fragments of memories reinstate an engram by way of nonsynaptic plasticity that permits its destabilization. Collectively, these findings seem to reinforce this hypothesis that electrotonic processing in non-ohmic dendrites yield insights into permanent electrical signatures that could reflect upon enduring memories as fragments of long-term memory engrams.

Matched MeSH terms: Epigenesis, Genetic
Fulltext Biological and clinical significance of the glypican-3 gene in human lung adenocarcinoma: An in silico analysis

Imon RR, Aktar S, Morshed N, Nur SM, Mahtarin R, Rahman FA, et al.

Medicine (Baltimore), 2023 Nov 10;102(45):e35347.
PMID: 37960765 DOI: 10.1097/MD.0000000000035347

Glypican-3 (GPC3), a membrane-bound heparan sulfate proteoglycan, has long been found to be dysregulated in human lung adenocarcinomas (LUADs). Nevertheless, the function, mutational profile, epigenetic regulation, co-expression profile, and clinicopathological significance of the GPC3 gene in LUAD progression are not well understood. In this study, we analyzed cancer microarray datasets from publicly available databases using bioinformatics tools to elucidate the above parameters. We observed significant downregulation of GPC3 in LUAD tissues compared to their normal counterparts, and this downregulation was associated with shorter overall survival (OS) and relapse-free survival (RFS). Nevertheless, no significant differences in the methylation pattern of GPC3 were observed between LUAD and normal tissues, although lower promoter methylation was observed in male patients. GPC3 expression was also found to correlate significantly with infiltration of B cells, CD8+, CD4+, macrophages, neutrophils, and dendritic cells in LUAD. In addition, a total of 11 missense mutations were identified in LUAD patients, and ~1.4% to 2.2% of LUAD patients had copy number amplifications in GPC3. Seventeen genes, mainly involved in dopamine receptor-mediated signaling pathways, were frequently co-expressed with GPC3. We also found 11 TFs and 7 miRNAs interacting with GPC3 and contributing to disease progression. Finally, we identified 3 potential inhibitors of GPC3 in human LUAD, namely heparitin, gemcitabine and arbutin. In conclusion, GPC3 may play an important role in the development of LUAD and could serve as a promising biomarker in LUAD.

Matched MeSH terms: Epigenesis, Genetic
Fulltext Molecular mechanisms underlying the clinical efficacy of panobinostat involve Stochasticity of epigenetic signaling, sensitization to anticancer drugs, and induction of cellular cell death related to cellular stresses

El Omari N, Bakrim S, Khalid A, Abdalla AN, Almalki WH, Lee LH, et al.

Biomed Pharmacother, 2023 Aug;164:114886.
PMID: 37224752 DOI: 10.1016/j.biopha.2023.114886

Panobinostat, also known as Farydak®, LBH589, PNB, or panobinostat lactate, is a hydroxamic acid that has been approved by the Food and Drug Administration (FDA) for its anti-cancer properties. This orally bioavailable drug is classified as a non-selective histone deacetylase inhibitor (pan-HDACi) that inhibits class I, II, and IV HDACs at nanomolar levels due to its significant histone modifications and epigenetic mechanisms. A mismatch between histone acetyltransferases (HATs) and HDACs can negatively affect the regulation of the genes concerned, which in turn can contribute to tumorigenesis. Indeed, panobinostat inhibits HDACs, potentially leading to acetylated histone accumulation, re-establishing normal gene expression in cancer cells, and helping to drive multiple signaling pathways. These pathways include induction of histone acetylation and cytotoxicity for the majority of tested cancer cell lines, increased levels of p21 cell cycle proteins, enhanced amounts of pro-apoptotic factors (such as caspase-3/7 activity and cleaved poly (ADP-ribose) polymerase (PARP)) associated with decreased levels of anti-apoptotic factors [B-cell lymphoma 2 (Bcl-2) and B-cell lymphoma-extra-large (Bcl-XL)], as well as regulation of immune response [upregulated programmed death-ligand 1 (PD-L1) and interferon gamma receptor 1 (IFN-γR1) expression] and other events. The therapeutic outcome of panobinostat is therefore mediated by sub-pathways involving proteasome and/or aggresome degradation, endoplasmic reticulum, cell cycle arrest, promotion of extrinsic and intrinsic processes of apoptosis, tumor microenvironment remodeling, and angiogenesis inhibition. In this investigation, we aimed to pinpoint the precise molecular mechanism underlying panobinostat's HDAC inhibitory effect. A more thorough understanding of these mechanisms will greatly advance our knowledge of cancer cell aberrations and, as a result, provide an opportunity for the discovery of significant new therapeutic perspectives through cancer therapeutics.

Matched MeSH terms: Epigenesis, Genetic
Fulltext Environmental and Genetic Traffic in the Journey from Sperm to Offspring

Sengupta P, Dutta S, Liew FF, Dhawan V, Das B, Mottola F, et al.

Biomolecules, 2023 Dec 07;13(12).
PMID: 38136630 DOI: 10.3390/biom13121759

Recent advancements in the understanding of how sperm develop into offspring have shown complex interactions between environmental influences and genetic factors. The past decade, marked by a research surge, has not only highlighted the profound impact of paternal contributions on fertility and reproductive outcomes but also revolutionized our comprehension by unveiling how parental factors sculpt traits in successive generations through mechanisms that extend beyond traditional inheritance patterns. Studies have shown that offspring are more susceptible to environmental factors, especially during critical phases of growth. While these factors are broadly detrimental to health, their effects are especially acute during these periods. Moving beyond the immutable nature of the genome, the epigenetic profile of cells emerges as a dynamic architecture. This flexibility renders it susceptible to environmental disruptions. The primary objective of this review is to shed light on the diverse processes through which environmental agents affect male reproductive capacity. Additionally, it explores the consequences of paternal environmental interactions, demonstrating how interactions can reverberate in the offspring. It encompasses direct genetic changes as well as a broad spectrum of epigenetic adaptations. By consolidating current empirically supported research, it offers an exhaustive perspective on the interwoven trajectories of the environment, genetics, and epigenetics in the elaborate transition from sperm to offspring.

Matched MeSH terms: Epigenesis, Genetic
Targeting the crosstalk of epigenetic modifications and immune evasion in nasopharyngeal cancer

Looi CK, Foong LC, Chung FF, Khoo AS, Loo EM, Leong CO, et al.

Cell Biol Toxicol, 2023 Dec;39(6):2501-2526.
PMID: 37755585 DOI: 10.1007/s10565-023-09830-9

Nasopharyngeal carcinoma (NPC) is a distinct type of head and neck cancer that is highly associated with Epstein-Barr virus (EBV) infection. EBV acts as an epigenetic driver in NPC tumorigenesis, reprogramming the viral and host epigenomes to regulate viral latent gene expression, and creating an environment conducive to the malignant transformation of nasopharyngeal epithelial cells. Targeting epigenetic mechanisms in pre-clinical studies has been shown promise in eradicating tumours and overcoming immune resistance in some solid tumours. However, its efficacy in NPC remains inclusive due to the complex nature of this cancer. In this review, we provide an updated understanding of the roles of epigenetic factors in regulating EBV latent gene expression and promoting NPC progression. We also explore the crosstalk between epigenetic mechanisms and immune evasion in NPC. Particularly, we discuss the potential roles of DNA methyltransferase (DNMT) and histone deacetylase (HDAC) inhibitors in reversing immune suppression and augmenting antitumour immunity. Furthermore, we highlight the advantages of combining epigenetic therapy and immune checkpoint inhibitor to reverse immune resistance and improve clinical outcomes. Epigenetic drugs have the potential to modulate both epigenetic mediators and immune factors involved in NPC. However, further research is needed to fully comprehend the diverse range of epigenetic modifications in NPC. A deeper understanding of the crosstalk between epigenetic mechanisms and immune evasion during NPC progression is crucial for the development of more effective treatments for this challenging disease.

Matched MeSH terms: Epigenesis, Genetic
Fulltext Association of Adverse Childhood Experiences With Accelerated Epigenetic Aging in Midlife

Kim K, Yaffe K, Rehkopf DH, Zheng Y, Nannini DR, Perak AM, et al.

JAMA Netw Open, 2023 Jun 01;6(6):e2317987.
PMID: 37306997 DOI: 10.1001/jamanetworkopen.2023.17987

IMPORTANCE: Adverse childhood experiences (ACEs) are associated with the risk of poorer health, and identifying molecular mechanisms may lay the foundation for health promotion in people with ACEs.
OBJECTIVE: To investigate the associations of ACEs with changes in epigenetic age acceleration (EAA), a biomarker associated with various health outcomes in middle-aged adults, in a population with balanced race and sex demographics.
DESIGN, SETTING, AND PARTICIPANTS: Data for this cohort study were from the Coronary Artery Risk Development in Young Adults (CARDIA) study. Participants in CARDIA underwent 8 follow-up exams from baseline (year 0 [Y0]; 1985-1986) to Y30 (2015-2016), and participant blood DNA methylation information was obtained at Y15 (2000-2001) and Y20 (2005-2006). Individuals from Y15 and Y20 with available DNA methylation data and complete variables for ACEs and covariates were included. Data were analyzed from September 2021 to August 2022.
EXPOSURES: Participant ACEs (general negligence, emotional negligence, physical violence, physical negligence, household substance abuse, verbal and emotional abuse, and household dysfunction) were obtained at Y15.
MAIN OUTCOMES AND MEASURES: The primary outcome consisted of results from 5 DNA methylation-based EAA measurements known to be associated with biological aging and long-term health: intrinsic EAA (IEAA), extrinsic EAA (EEAA), PhenoAge acceleration (PhenoAA), GrimAge acceleration (GrimAA), and Dunedin Pace of Aging Calculated From the Epigenome (DunedinPACE), measured at Y15 and Y20. Linear regression and generalized estimating equations were used to assess associations of the burden of ACEs (≥4 vs <4 ACEs) with EAA adjusting for demographics, health-related behaviors, and early life and adult socioeconomic status.
RESULTS: A total of 895 participants for Y15 (mean [SD] age, 40.4 [3.5] years; 450 males [50.3%] and 445 females [49.7%]; 319 Black [35.6%] and 576 White [64.4%]) and 867 participants for Y20 (mean [SD] age, 45.4 [3.5] years; 432 males [49.8%] and 435 females [50.2%]; 306 Black [35.3%] and 561 White [64.7%]) were included after excluding participants with missing data. There were 185 participants with (20.7%) vs 710 participants without (79.3%) 4 or more ACEs at Y15 and 179 participants with (20.6%) vs 688 participants without (79.4%) 4 or more ACEs at Y20. Having 4 or more ACEs was positively associated with EAA in years at Y15 (EEAA: β = 0.60 years; 95% CI, 0.18-1.02 years; PhenoAA: β = 0.62 years; 95% CI = 0.13-1.11 years; GrimAA: β = 0.71 years; 95% CI, 0.42-1.00 years; DunedinPACE: β = 0.01; 95% CI, 0.01-0.02) and Y20 (IEAA: β = 0.41 years; 95% CI, 0.05-0.77 years; EEAA: β = 1.05 years; 95% CI, 0.66-1.44 years; PhenoAA: β = 0.57 years; 95% CI, 0.08-1.05 years; GrimAA: β = 0.57 years; 95% CI, 0.28-0.87 years; DunedinPACE: β = 0.01; 95% CI, 0.01-0.02) after adjusting for demographics, health-related behaviors, and socioeconomic status.
CONCLUSIONS AND RELEVANCE: In this cohort study, ACEs were associated with EAA among middle-aged adults after controlling for demographics, behavior, and socioeconomic status. These findings of the associations between early life experience and the biological aging process in midlife may contribute to health promotion in a life course perspective.

Matched MeSH terms: Epigenesis, Genetic
Fulltext Ageing, Drosophila melanogaster and Epigenetics

Halim MA, Tan FHP, Azlan A, Rasyid II, Rosli N, Shamsuddin S, et al.

Malays J Med Sci, 2020 May;27(3):7-19.
PMID: 32684802 MyJurnal DOI: 10.21315/mjms2020.27.3.2

Ageing is a phenomenon where the accumulation of all the stresses that alter the functions of living organisms, halter them from maintaining their physiological balance and eventually lead to death. The emergence of epigenetic tremendously contributed to the knowledge of ageing. Epigenetic changes in cells or tissues like deoxyribonucleic acid (DNA) methylation, modification of histone proteins, transcriptional modification and also the involvement of non-coding DNA has been documented to be associated with ageing. In order to study ageing, scientists have taken advantage of several potential organisms to aid them in their study. Drosophila melanogaster has been an essential model in establishing current understanding of the mechanism of ageing as they possess several advantages over other competitors like having homologues to more than 75% of human disease genes, having 50% of Drosophila genes are homologues to human genes and most importantly they are genetically amenable. Here, we would like to summarise the extant knowledge about ageing and epigenetic process and the role of Drosophila as an ideal model to study epigenetics in association with ageing process.

Matched MeSH terms: Epigenesis, Genetic
Expression profiling of choline and ethanolamine kinases in MCF7, HCT116 and HepG2 cells, and the transcriptional regulation by epigenetic modification

Ling CS, Yin KB, Cun ST, Ling FL

Mol Med Rep, 2015 Jan;11(1):611-8.
PMID: 25333818 DOI: 10.3892/mmr.2014.2707

The function of choline kinase (CK) and ethanolamine kinase (EK) is to catalyse the phosphorylation of choline and ethanolamine, respectively, in order to yield phosphocholine (PCho) and phosphoethanolamine (PEtn). A high expression level of PCho, due to elevated CK activity, has previously been associated with malignant transformation. In the present study, a quantitative polymerase chain reaction was performed to determine the mRNA expression profiles of ck and ek mRNA variants in MCF7 breast, HCT116 colon and HepG2 liver cancer cells. The ck and ek mRNA expression profiles showed that total ckα was expressed most abundantly in the HepG2 cells. The HCT116 cells exhibited the highest ckβ and ek1 mRNA expression levels, whereas the highest ek2α mRNA expression levels were detected in the MCF7 cells. The ckβ variant had higher mRNA expression levels, as compared with total ckα, in both the MCF7 and HCT116 cells. Relatively low ek1 mRNA expression levels were detected, as compared with ek2α in the MCF7 cells; however, this was not observed in the HCT116 and HepG2 cells. Notably, the mRNA expression levels of ckα2 were markedly low, as compared with ckα1, in all three cancer cell lines. The effects of epigenetic modification on ck and ek mRNA expression, by treatment of the cells with the histone deacetylase inhibitor trichostatin A (TSA), were also investigated. The results of the present study showed that the mRNA expression levels of ckα, ckβ and ek2α were affected by TSA. An increase >8-fold was observed in ek2α mRNA expression upon treatment with TSA, in a concentration- and time-dependent manner. In conclusion, the levels of ck and ek transcript variants in the three cancer cell lines were varied. The effects of TSA treatment on the mRNA expression levels of ck and ek imply that ck and ek mRNA expression may be regulated by epigenetic modification.

Matched MeSH terms: Epigenesis, Genetic*
Current Genetic and Epigenetic Insights into Type 2 Diabetes Mellitus

Alam F, Kamal MA, Islam MA, Banu S

Endocr Metab Immune Disord Drug Targets, 2019;19(6):717-718.
PMID: 31530259 DOI: 10.2174/187153031906190724104004
Matched MeSH terms: Epigenesis, Genetic/physiology*
Overview on Epigenetic Re-programming: A Potential Therapeutic Intervention in Triple Negative Breast Cancers

Mohamad Hanif EA, Shah SA

Asian Pac J Cancer Prev, 2018 Dec 25;19(12):3341-3351.
PMID: 30583339

Breast cancer treatments leads to variable responses. Hormonal therapy is beneficial to receptor positive breast cancer
subtypes and display better clinical outcome than triple negative breast cancers (TNBCs) with FEC (5-Fluorouracil,
Epirubicin and Cyclophosphamide) the mainstay chemotherapy regiment. Owning to their negative expressions of
estrogen (ER), progesterone (PR) and HER2 receptors, disease recurrence and metastasis befalls some patients indicating
resistance to FEC. Involvement of epigenetic silencing through DNA methylation, histone methylation, acetylation and
sumoylation may be the key player in FEC chemoresistance. Epigenetic and molecular profiling successfully classified
breast cancer subtypes, indicating potential driver mechanisms to the progression of TNBCs but functional mechanisms
behind chemoresistance of these molecular markers are not well defined. Several epigenetic inhibitors and drugs have
been used in the management of cancers but these attempts are mainly beneficial in hematopoietic cancers and not
specifically favourable in solid tumours. Hypothetically, upon administration of epigenetic drugs, recovery of tumour
suppressor genes is expected. However, high tendency of switching on global metastatic genes is predicted. Polycomb
repressive complex (PRC) such as EZH2, SETD1A, DNMT, is known to have repressive effects in gene regulation and
shown to inhibit cell proliferation and invasion in breast cancers. Individual epigenetic regulators may be an option
to improve chemo-drug delivery in cancers. This review discussed on molecular signatures of various breast cancer
subtypes and on-going attempts in understanding underlying molecular mechanisms of epigenetic regulators as well
as providing insights on possible ways to utilize epigenetic enzymes/inhibitors with responses to chemotherapeutic
drugs to re-program cellular and biological outcome in TNBCs.

Matched MeSH terms: Epigenesis, Genetic/genetics*
Fulltext Triallelic and epigenetic-like inheritance in human disorders of telomerase

Collopy LC, Walne AJ, Cardoso S, de la Fuente J, Mohamed M, Toriello H, et al.

Blood, 2015 Jul 09;126(2):176-84.
PMID: 26024875 DOI: 10.1182/blood-2015-03-633388

Dyskeratosis congenita (DC) and related diseases are a heterogeneous group of disorders characterized by impaired telomere maintenance, known collectively as the telomeropathies. Disease-causing variants have been identified in 10 telomere-related genes including the reverse transcriptase (TERT) and the RNA component (TERC) of the telomerase complex. Variants in TERC and TERT can impede telomere elongation causing stem cells to enter premature replicative senescence and/or apoptosis as telomeres become critically short. This explains the major impact of the disease on highly proliferative tissues such as the bone marrow and skin. However, telomerase variants are not always fully penetrant and in some families disease-causing variants are seen in asymptomatic family members. As a result, determining the pathogenic status of newly identified variants in TERC or TERT can be quite challenging. Over a 3-year period, we have identified 26 telomerase variants (16 of which are novel) in 23 families. Additional investigations (including family segregation and functional studies) enabled these to be categorized into 3 groups: (1) disease-causing (n = 15), (2) uncertain status (n = 6), and (3) bystanders (n = 5). Remarkably, this process has also enabled us to identify families with novel mechanisms of inheriting human telomeropathies. These include triallelic mutations, involving 2 different telomerase genes, and an epigenetic-like inheritance of short telomeres in the absence of a telomerase mutation. This study therefore highlights that telomerase variants have highly variable functional and clinical manifestations and require thorough investigation to assess their pathogenic contribution.

Matched MeSH terms: Epigenesis, Genetic*
Deoxyribonucleic acid (DNA) methylation in children exposed to air pollution: a possible mechanism underlying respiratory health effects development

Suhaimi NF, Jalaludin J, Abu Bakar S

Rev Environ Health, 2021 Mar 26;36(1):77-93.
PMID: 32857724 DOI: 10.1515/reveh-2020-0065

Air pollution is a substantial environmental threat to children and acts as acute and chronic disease risk factors alike. Several studies have previously evaluated epigenetic modifications concerning its exposure across various life stages. However, findings on epigenetic modifications as the consequences of air pollution during childhood are rather minimal. This review evaluated highly relevant studies in the field to analyze the existing literature regarding exposure to air pollution, with a focus on epigenetic alterations during childhood and their connections with respiratory health effects. The search was conducted using readily available electronic databases (PubMed and ScienceDirect) to screen for children's studies on epigenetic mechanisms following either pre- or post-natal exposure to air pollutants. Studies relevant enough and matched the predetermined criteria were chosen to be reviewed. Non-English articles and studies that did not report both air monitoring and epigenetic outcomes in the same article were excluded. The review found that epigenetic changes have been linked with exposure to air pollutants during early life with evidence and reports of how they may deregulate the epigenome balance, thus inducing disease progression in the future. Epigenetic studies evolve as a promising new approach in deciphering the underlying impacts of air pollution on deoxyribonucleic acid (DNA) due to links established between some of these epigenetic mechanisms and illnesses.

Matched MeSH terms: Epigenesis, Genetic/drug effects*
New insights on brain-derived neurotrophic factor epigenetics: from depression to memory extinction

Poon CH, Heng BC, Lim LW

Ann N Y Acad Sci, 2021 01;1484(1):9-31.
PMID: 32808327 DOI: 10.1111/nyas.14458

Advances in characterizing molecular profiles provide valuable insights and opportunities for deciphering the neuropathology of depression. Although abnormal brain-derived neurotrophic factor (BDNF) expression in depression has gained much support from preclinical and clinical research, how it mediates behavioral alterations in the depressed state remains largely obscure. Environmental factors contribute significantly to the onset of depression and produce robust epigenetic changes. Epigenetic regulation of BDNF, as one of the most characterized gene loci in epigenetics, has recently emerged as a target in research on memory and psychiatric disorders. Specifically, epigenetic alterations of BDNF exons are heavily involved in mediating memory functions and antidepressant effects. In this review, we discuss key research on stress-induced depression from both preclinical and clinical studies, which revealed that differential epigenetic regulation of specific BDNF exons is associated with depression pathophysiology. Considering that BDNF has a central role in depression, we argue that memory extinction, an adaptive response to fear exposure, is dependent on BDNF modulation and holds promise as a prospective target for alleviating or treating depression and anxiety disorders.

Matched MeSH terms: Epigenesis, Genetic/genetics*
Fulltext Genetic and Global Epigenetic Modification, Which Determines the Phenotype of Transgenic Rice?

Fan X, Chen J, Wu Y, Teo C, Xu G, Fan X

Int J Mol Sci, 2020 Mar 06;21(5).
PMID: 32155767 DOI: 10.3390/ijms21051819

Transgenic technologies have been applied to a wide range of biological research. However, information on the potential epigenetic effects of transgenic technology is still lacking. Here, we show that the transgenic process can simultaneously induce both genetic and epigenetic changes in rice. We analyzed genetic, epigenetic, and phenotypic changes in plants subjected to tissue culture regeneration, using transgenic lines expressing the same coding sequence from two different promoters in transgenic lines of two rice cultivars: Wuyunjing7 (WYJ7) and Nipponbare (NP). We determined the expression of OsNAR2.1 in two overexpression lines generated from the two cultivars, and in the RNA interference (RNAi) OsNAR2.1 line in NP. DNA methylation analyses were performed on wild-type cultivars (WYJ7 and NP), regenerated lines (CK, T0 plants), segregation-derived wild-type from pOsNAR2.1-OsNAR2.1 (SDWT), pOsNAR2.1-OsNAR2.1, pUbi-OsNAR2.1, and RNAi lines. Interestingly, we observed global methylation decreased in the T0 regenerated line of WYJ7 (CK-WJY7) and pOsNAR2.1-OsNAR2.1 lines but increased in pUbi-OsNAR2.1 and RNAi lines of NP. Furthermore, the methylation pattern in SDWT returned to the WYJ7 level after four generations. Phenotypic changes were detected in all the generated lines except for SDWT. Global methylation was found to decrease by 13% in pOsNAR2.1-OsNAR2.1 with an increase in plant height of 4.69% compared with WYJ7, and increased by 18% in pUbi-OsNAR2.1 with an increase of 17.36% in plant height compared with NP. This suggests an absence of a necessary link between global methylation and the phenotype of transgenic plants with OsNAR2.1 gene over-expression. However, epigenetic changes can influence phenotype during tissue culture, as seen in the massive methylation in CK-WYJ7, T0 regenerated lines, resulting in decreased plant height compared with the wild-type, in the absence of a transformed gene. We conclude that in the transgenic lines the phenotype is mainly determined by the nature and function of the transgene after four generations of transformation, while the global epigenetic modification is dependent on the genetic background. Our research suggests an innovative insight in explaining the reason behind the occurrence of transgenic plants with random and undesirable phenotypes.

Matched MeSH terms: Epigenesis, Genetic*
Fulltext Methylenetetrahydrofolate Reductase CpG Islands: Epigenotyping

Wei LK, Sutherland H, Au A, Camilleri E, Haupt LM, Gan SH, et al.

J Clin Lab Anal, 2016 Jul;30(4):335-44.
PMID: 26109141 DOI: 10.1002/jcla.21860

BACKGROUND: Determination of the differential DNA methylation patterns of methylenetetrahydrofolate reductase (MTHFR) that are associated with differential MTHFR activity is important to understand the pathogenesis of ischemic stroke. However, to date, no data are available on the differential DNA methylation profiles of Kelantanese Malays. Therefore, we developed a rapid and efficient serial pyrosequencing assay to determine differential DNA methylation profiles of MTHFR, which help to further our understanding of the pathogenesis of ischemic stroke. The developed assay also served as the validation platform for our previous computational epigenetic research on MTHFR.
METHODS: Polymerase chain reaction primers were designed and validated to specifically amplify the cytosine that is followed by guanine residues (CpGs) A and B regions. Prior epigenotyping on 110 Kelantanese Malays, the serial pyrosequencing assays for the CpGs A and B regions were validated using five validation controls. The mean values of the DNA methylation profiles of CpGs A and B were calculated.
RESULTS: The mean DNA methylation levels for CpGs A and B were 0.984 ± 0.582 and 2.456 ± 1.406, respectively. The CpGs 8 and 20 showed the highest (5.581 ± 4.497) and the lowest (0.414 ± 2.814) levels of DNA methylation at a single-base resolution.
CONCLUSION: We have successfully developed and validated a pyrosequencing assay that is fast and can yield high-quality pyrograms for DNA methylation analysis and is therefore applicable to high throughput study. Using this newly developed pyrosequencing assay, the MTHFR DNA methylation profiles of 110 Kelantanese Malays were successfully determined. It also validated our computational epigenetic research on MTHFR.

Matched MeSH terms: Epigenesis, Genetic*
Fulltext Harnessing the Potential of CRISPR/Cas in Atherosclerosis: Disease Modeling and Therapeutic Applications

Siew WS, Tang YQ, Kong CK, Goh BH, Zacchigna S, Dua K, et al.

Int J Mol Sci, 2021 Aug 05;22(16).
PMID: 34445123 DOI: 10.3390/ijms22168422

Atherosclerosis represents one of the major causes of death globally. The high mortality rates and limitations of current therapeutic modalities have urged researchers to explore potential alternative therapies. The clustered regularly interspaced short palindromic repeats-associated protein 9 (CRISPR/Cas9) system is commonly deployed for investigating the genetic aspects of Atherosclerosis. Besides, advances in CRISPR/Cas system has led to extensive options for researchers to study the pathogenesis of this disease. The recent discovery of Cas9 variants, such as dCas9, Cas9n, and xCas9 have been established for various applications, including single base editing, regulation of gene expression, live-cell imaging, epigenetic modification, and genome landscaping. Meanwhile, other Cas proteins, such as Cas12 and Cas13, are gaining popularity for their applications in nucleic acid detection and single-base DNA/RNA modifications. To date, many studies have utilized the CRISPR/Cas9 system to generate disease models of atherosclerosis and identify potential molecular targets that are associated with atherosclerosis. These studies provided proof-of-concept evidence which have established the feasibility of implementing the CRISPR/Cas system in correcting disease-causing alleles. The CRISPR/Cas system holds great potential to be developed as a targeted treatment for patients who are suffering from atherosclerosis. This review highlights the advances in CRISPR/Cas systems and their applications in establishing pathogenetic and therapeutic role of specific genes in atherosclerosis.

Matched MeSH terms: Epigenesis, Genetic/genetics
Fulltext A concise review on epigenetic regulation: insight into molecular mechanisms

Golbabapour S, Abdulla MA, Hajrezaei M

Int J Mol Sci, 2011;12(12):8661-94.
PMID: 22272098 DOI: 10.3390/ijms12128661

Epigenetic mechanisms are responsible for the regulation of transcription of imprinted genes and those that induce a totipotent state. Starting just after fertilization, DNA methylation pattern undergoes establishment, reestablishment and maintenance. These modifications are important for normal embryo and placental developments. Throughout life and passing to the next generation, epigenetic events establish, maintain, erase and reestablish. In the context of differentiated cell reprogramming, demethylation and activation of genes whose expressions contribute to the pluripotent state is the crux of the matter. In this review, firstly, regulatory epigenetic mechanisms related to somatic cell nuclear transfer (SCNT) reprogramming are discussed, followed by embryonic development, and placental epigenetic issues.

Matched MeSH terms: Epigenesis, Genetic*
Reprogramming cancer cells: overview & current progress

Lim KL, Teoh HK, Choong PF, Teh HX, Cheong SK, Kamarul T

Expert Opin Biol Ther, 2016 07;16(7):941-51.
PMID: 27070264 DOI: 10.1517/14712598.2016.1174211

INTRODUCTION: Cancer is a disease with genetic and epigenetic origins, and the possible effects of reprogramming cancer cells using the defined sets of transcription factors remain largely uninvestigated. In the handful of publications available so far, findings have shown that reprogramming cancer cells changed the characteristics of the cells to differ from the parental cancer cells. These findings indicated the possibility of utilizing reprogramming technology to create a disease model in the laboratory to be used in studying the molecular pathogenesis or for drug screening of a particular cancer model.
AREAS COVERED: Despite numerous methods employed in generating induced pluripotent stem cells (iPSCs) from cancer cells only a few studies have successfully reprogrammed malignant human cells. In this review we will provide an overview on i) methods to reprogram cancer cells, ii) characterization of the reprogrammed cancer cells, and iii) the differential effects of reprogramming on malignancy, epigenetics and response of the cancer cells to chemotherapeutic agents.
EXPERT OPINION: Continued technical progress in cancer cell reprogramming technology will be instrumental for more refined in vitro disease models and ultimately for the development of directed and personalized therapy for cancer patients in the future.

Matched MeSH terms: Epigenesis, Genetic/drug effects; Epigenesis, Genetic/physiology*
Developmental programing of thirst and sodium appetite

Mecawi AS, Macchione AF, Nuñez P, Perillan C, Reis LC, Vivas L, et al.

Neurosci Biobehav Rev, 2015 Apr;51:1-14.
PMID: 25528684 DOI: 10.1016/j.neubiorev.2014.12.012

Thirst and sodium appetite are the sensations responsible for the motivated behaviors of water and salt intake, respectively, and both are essential responses for the maintenance of hydromineral homeostasis in animals. These sensations and their related behaviors develop very early in the postnatal period in animals. Many studies have demonstrated several pre- and postnatal stimuli that are responsible for the developmental programing of thirst and sodium appetite and, consequently, the pattern of water and salt intake in adulthood in need-free or need-induced conditions. The literature systematically reports the involvement of dietary changes, hydromineral and cardiovascular challenges, renin-angiotensin system and steroid hormone disturbances, and lifestyle in these developmental factors. Therefore, this review will address how pre- and postnatal challenges can program lifelong thirst and sodium appetite in animals and humans, as well as which neuroendocrine substrates are involved. In addition, the possible epigenetic molecular mechanisms responsible for the developmental programing of drinking behavior, the clinical implications of hydromineral disturbances during pre- and postnatal periods, and the developmental origins of adult hydromineral behavior will be discussed.

Matched MeSH terms: Epigenesis, Genetic
Fulltext Cancer reversion with oocyte extracts is mediated by cell cycle arrest and induction of tumour dormancy

Saad N, Alberio R, Johnson AD, Emes RD, Giles TC, Clarke P, et al.

Oncotarget, 2018 Mar 23;9(22):16008-16027.
PMID: 29662623 DOI: 10.18632/oncotarget.24664

Inducing stable control of tumour growth by tumour reversion is an alternative approach to cancer treatment when eradication of the disease cannot be achieved. The process requires re-establishment of normal control mechanisms that are lost in cancer cells so that abnormal proliferation can be halted. Embryonic environments can reset cellular programmes and we previously showed that axolotl oocyte extracts can reprogram breast cancer cells and reverse their tumorigenicity. In this study, we analysed the gene expression profiles of oocyte extract-treated tumour xenografts to show that tumour reprogramming involves cell cycle arrest and acquisition of a quiescent state. Tumour dormancy is associated with increased P27 expression, restoration of RB function and downregulation of mitogen-activated signalling pathways. We also show that the quiescent state is associated with increased levels of H4K20me3 and decreased H4K20me1, an epigenetic profile leading to chromatin compaction. The epigenetic reprogramming induced by oocyte extracts is required for RB hypophosphorylation and induction of P27 expression, both occurring during exposure to the extracts and stably maintained in reprogrammed tumour xenografts. Therefore, this study demonstrates the value of oocyte molecules for inducing tumour reversion and for the development of new chemoquiescence-based therapies.

Matched MeSH terms: Epigenesis, Genetic

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