• BMB Reports
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• v.40 no.2
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• pp.142-150
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• 2007

Epigenetic alterations, represented by aberrant DNA methylation, are deeply involved in human cancers. In gastric cancers, tumor-suppressor genes are inactivated more frequently by promoter methylation than by mutations. We recently showed that H. pylori infection, a potent gastric carcinogenic factor, induces methylation of specific genes in the gastric mucosae. When the methylation levels were analyzed in the gastric mucosae of healthy volunteers, cases with a single gastric cancer, and cases with multiple gastric cancers, who have increasing levels of risks for gastric cancers, there was a significant increasing trend in the methylation levels among the individuals without current H. pylori infection. This finding unequivocally showed the presence of an epigenetic field for cancerization. The degree of the field defect was measured more conveniently using methylation levels of marker genes than using those of tumor-suppressor genes. The presence of an epigenetic field for cancerization has been indicated for liver, colon, Barrett's esophageal, lung, breast, and renal cancers. Since decreased transcription is involved in the specificity of methylated genes, it is likely that specific genes are methylated according to carcinogenic factors. These findings emphasize the usefulness of DNA methylation as a marker for past exposure to carcinogens and future risk of cancer development.

• BMB Reports
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• v.43 no.10
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• pp.649-655
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• 2010

Alzheimer's disease (AD) is the most common age-dependent neurodegenerative disorder and shows progressive memory loss and cognitive decline. Intraneuronal filaments composed of aggregated hyperphosphorylated tau protein, called neurofibrillary tangles, along with extracellular accumulations of amyloid $\beta$ protein (A$\beta$), called senile plaques, are known to be the neuropathological hallmarks of AD. In light of recent studies, epigenetic modification has emerged as one of the pathogenic mechanisms of AD. Epigenetic changes encompass an array of molecular modifications to both DNA and chromatin, including transcription factors and cofactors. In this review, we summarize how DNA methylation and changes to DNA chromatin packaging by post-translational histone modification are involved in AD. In addition, we describe the role of SIRTs, histone deacetylases, and the effect of SIRT-modulating drugs on AD. Lastly, we discuss how amyloid precursor protein (APP) intracellular domain (AICD) regulates neuronal transcription. Our understanding of the epigenomes and transcriptomes of AD may warrant future identification of novel biological markers and beneficial therapeutic targets for AD.

• Journal of Life Science
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• v.33 no.9
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• pp.736-745
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• 2023

Aging is a complex biological process characterized by a gradual decline in cellular and physiological functions. This natural process is associated with age-related diseases, including Alzheimer's disease, atherosclerosis, and hypogonadism, which are significant health concerns among older individuals and can significantly impact their quality of life. Researchers have found that epigenetic markers play a crucial role in regulating aging and age-related diseases. Epigenetic markers are heritable gene expression alterations that do not change in the DNA sequence. This review focuses on the involvement of various epigenetic marks, such as RNA methylation, DNA methylation, and microRNAs (miRNAs), in regulating gene expression patterns associated with age-related diseases, such as Alzheimer's disease, atherosclerosis, and hypogonadism. These epigenetic alterations can lead to the dysregulation of specific genes and signaling pathways, contributing to the development and progression of Alzheimer's disease, atherosclerosis, and hypogonadism. Understanding the molecular mechanisms behind these epigenetic modifications is essential for both the aging population and individuals seeking ways to promote overall well-being. By gaining deeper insights into how epigenetic marker alteration occurs during aging and age-related diseases, researchers can potentially develop targeted therapeutic strategies to alleviate the impact of these conditions and improve the quality of life for older individuals.

• Journal of Genetic Medicine
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• v.12 no.2
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• pp.100-108
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• 2015

Purpose: Conventional methods for the prenatal detection of fetal RhD status involve invasive procedures such as fetal blood sampling and amniocentesis. The identification of cell-free fetal DNA (cffDNA) in maternal plasma creates the possibility of determining fetal RhD status by analyzing maternal plasma DNA. However, some technical problems still exist, especially the lack of a positive control marker for the presence of fetal DNA. Therefore, we assessed the feasibility and accuracy of fetal RHD genotyping incorporating the RASSF1A epigenetic fetal DNA marker from cffDNA in the maternal plasma of RhD-negative pregnant women in Korea. Materials and Methods: We analyzed maternal plasma from 41 pregnant women identified as RhD-negative by serological testing. Multiplex real-time PCR was performed by amplifying RHD exons 5 and 7 and the SRY gene, with RASSF1A being used as a gender-independent fetal epigenetic marker. The results were compared with those obtained by postnatal serological analysis of cord blood and gender identification. Results: Among the 41 fetuses, 37 were RhD-positive and 4 were RhD-negative according to the serological analysis of cord blood. There was 100% concordance between fetal RHD genotyping and serological cord blood results. Detection of the RASSF1A gene verified the presence of cffDNA, and the fetal SRY status was correctly detected in all 41 cases. Conclusion: Noninvasive fetal RHD genotyping with cffDNA incorporating RASSF1A is a feasible, reliable, and accurate method of determining fetal RhD status. It is an alternative to amniocentesis for the management of RhD-negative women and reduces the need for unnecessary RhIG prophylaxis.

• BMB Reports
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• v.55 no.7
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• pp.342-347
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• 2022

Defense priming allows plants to enhance their immune responses to subsequent pathogen challenges. Recent reports suggested that acquired resistances in parental generation can be inherited into descendants. Although epigenetic mechanisms are plausible tools enabling the transmission of information or phenotypic traits induced by environmental cues across generations, the mechanism for the transgenerational inheritance of defense priming in plants has yet to be elucidated. With the initial aim to elucidate an epigenetic mechanism for the defense priming in plants, we reassessed the transgenerational inheritance of plant defense, however, could not observe any evidence supporting it. By using the same dipping method with previous reports, Arabidopsis was exposed repeatedly to Pseudomonas syringae pv tomato DC3000 (Pst DC3000) during vegetative or reproductive stages. Irrespective of the developmental stages of parental plants that received pathogen infection, the descendants did not exhibit primed resistance phenotypes, defense marker gene (PR1) expression, or elevated histone acetylation within PR1 chromatin. In assays using the pressure-infiltration method for infection, we obtained the same results as above. Thus, our results suggest that the previous observations on the transgenerational inheritance of defense priming in plants should be more extensively and carefully reassessed.

• Reproductive and Developmental Biology
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• v.32 no.2
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• pp.135-140
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• 2008

Recent studies on nuclear transfer and induced pluripotent stem cells have demonstrated that differentiated somatic cells can be returned to the undifferentiated state by reversing their developmental process. These epigenetically reprogrammed somatic cells may again be differentiated into various cell types, and used for cell replacement therapies through autologous transplantation to treat many degenerative diseases. To date, however, reprogramming of somatic cells into undifferentiated cells has been extremely inefficient. Hence, reliable markers to identify the event of reprogramming would assist effective selection of reprogrammed cells. In this study, a transgene construct encoding enhanced green fluorescent protein (EGFP) under the regulation of human Oct4 promoter was developed as a reporter for the reprogramming of somatic cells. Microinjection of the transgene construct into pronuclei of fertilized mouse eggs resulted in the emission of green fluorescence, suggesting that the undifferentiated cytoplasmic environment provided by fertilized eggs induces the expression of EGFP. Next, the transgene construct was introduced into human embryonic fibroblasts, and the nuclei from these cells were transferred into enucleated porcine oocytes. Along with their in vitro development, nuclear transfer embryos emitted green fluorescence, suggesting the reprogramming of donor nuclei in nuclear transfer embryos. The results of the present study demonstrate that expression of the transgene under the regulation of human Oct4 promoter coincides with epigenetic reprogramming, and may be used as a convenient marker that non-invasively reflects reprogramming of somatic cells.

• Journal of Genetic Medicine
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• v.14 no.1
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• pp.1-7
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• 2017

Purpose: The aim of this study was to assess the diagnostic efficacy of noninvasive prenatal screening for trisomy 18 by assessing the levels of unmethylated-maspin (U-maspin) and fetal nuchal translucency (NT) thickness during the first trimester of pregnancy. Materials and Methods: A nested case-control study was conducted using maternal plasma samples collected from 65 pregnant women carrying 11 fetuses with trisomy 18 and 54 normal fetuses. We compared the U-maspin levels, NT thicknesses, or a combination of both in the first trimester between the case and control groups. Results: U-maspin levels and NT thickness were significantly elevated in the first trimester in pregnant women carrying fetuses with trisomy 18 when compared to those carrying normal fetuses (27.2 vs. 6.6 copies/mL, P<0.001 for U-maspin; 5.9 vs. 2.0 mm, P<0.001 for NT). The sensitivities of the U-maspin levels and NT thickness in prenatal screening for fetal trisomy 18 were 90.9% and 90.9%, respectively, with a specificity of 98.1%. The combined U-maspin levels and NT thickness had a sensitivity of 100% in prenatal screening for fetal trisomy 18, with a specificity of 98.1%. Conclusion: A combination of U-maspin levels and NT thickness is highly efficacious for noninvasive prenatal screening of fetal trisomy 18 in the first trimester of pregnancy.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.7
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• pp.3489-3493
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• 2012

Hepatocellular carcinoma (HCC), the most common primary hepatic tumor, is highly prevalent in the Asia-Pacific region, including Thailand. Many genetic and epigenetic alterations in HCC have been elucidated. The aim of this study was to determine whether aberrant methylation of the suppressor of cytokine signaling 1 gene (SOCS1) occurs in HCCs. Methylation specific-PCR assays were performed to identify the methylation status of SOCS1 in 29 tumors and their corresponding normal liver tissues. An abnormal methylation status was detected in 17 (59%), with a higher prevalence of aberrant SOCS1 methylation significantly correlating with HCC treated without chemotherapy (OR=0.04, 95%CI=0.01-0.31; P=0.001). This study suggests that epigenetic aberrant SOCS1 methylation may be a predictive marker for HCC patients.

• Journal of Plant Biotechnology
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• v.50
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• pp.190-199
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• 2023

Date palm (Phoenix dactylifera L.: Arecaceae) is a dioecious species where only female trees bear fruits. In their natural state, date palms produce dates once a year. However, in Thailand, some trees were observed to produce dates during the off-season, despite no variations in morphology. The availability of such off-season fruits can significantly increase their market value. Interestingly, most female off-season date palms investigated in this study were obtained through micropropagation. Hence, there is an urgent need for genetic markers to distinguish female offseason flowering plantlets within tissue culture systems. In this study, we aimed to develop random amplification of polymorphic DNA-sequence characterized amplified region (RAPD-SCAR) markers for the identification of female off-season flowering date palms cultivated in Thailand. A total of 160 random decamer primers were employed to screen for specific RAPD markers in off-season flowering male and female populations. Out of these, only one primer, OPN-02, generated distinct genomic DNA patterns in female off-season flowering (FOFdp) individuals compared to female seasonal flowering genotypes. Based on the RAPD-specific sequence, specific SCAR primers denoted as FOFdpF and FOFdpR were developed. These SCAR primers amplified a single 517-bp DNA fragment, predominantly found in off-season flowering populations, with an accuracy rate of 60%. These findings underscore the potential of SCAR marker technology for tracking offseason flowering in date palms. Notably, a BLAST analysis revealed a substantial similarity between the SCAR marker sequence and the transcript variant mRNA from Phoenix dactylifera encoding the SET DOMAIN GROUP 40 protein. In Arabidopsis, this protein is involved in the epigenetic regulation of flowering time. The genetic potential of the off-season flowering traits warrants further elucidation.

• Genomics & Informatics
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• v.10 no.2
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• pp.74-80
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• 2012

Most genes are processed by alternative splicing for gene expression, resulting in the complexity of the transcriptome in eukaryotes. It allows a limited number of genes to encode various proteins with intricate functions. Alternative splicing is regulated by genetic mutations in cis-regulatory factors and epigenetic events. Furthermore, splicing events occur differently according to cell type, developmental stage, and various diseases, including cancer. Genome instability and flexible proteomes by alternative splicing could affect cancer cells to grow and survive, leading to metastasis. Cancer cells that are transformed by aberrant and uncontrolled mechanisms could produce alternative splicing to maintain and spread them continuously. Splicing variants in various cancers represent crucial roles for tumorigenesis. Taken together, the identification of alternative spliced variants as biomarkers to distinguish between normal and cancer cells could cast light on tumorigenesis.