• Molecules and Cells
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• 제38권6호
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• pp.518-527
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• 2015

Controlled release of medications remains the most convenient way to deliver drugs. In this study, we precipitated gold nanoparticles with quercetin. We loaded gold-quercetin into poly(DL-lactide-co-glycolide) nanoparticles (NQ) and tested the biological activity of NQ on HepG2 hepatocarcinoma cells to acquire the sustained release property. We determined by circular dichroism spectroscopy that NQ effectively caused conformational changes in DNA and modulated different proteins related to epigenetic modifications and c ell cycle control. The mitochondrial membrane potential (MMP), reactive oxygen species (ROS), cell cycle, apoptosis, DNA damage, and caspase 3 activity were analyzed by flow cytometry, and the expression profiles of different anti- and pro-apoptotic as well as epigenetic signals were studied by immunoblotting. A cytotoxicity assay indicated that NQ preferentially killed cancer cells, compared to normal cells. NQ interacted with HepG2 cell DNA and reduced histone deacetylases to control cell proliferation and arrest the cell cycle at the sub-G stage. Activities of cell cycle-related proteins, such as $p21^{WAF}$, cdk1, and pAkt, were modulated. NQ induced apoptosis in HepG2 cells by activating p53-ROS crosstalk and induces epigenetic modifications leading to inhibited proliferation and cell cycle arrest.

• 한국식품영양과학회:학술대회논문집
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• 한국식품영양과학회 2004년도 Annual Meeting and International Symposium
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• pp.271-274
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• 2004

Nutritional genomics is a new field of study of how nutrition interacts with an individual's genome or individual responds to individual diets. Systematic approach of nutritional genomics will likely provide important clues about responders and non-responders. The current interest in personalizing health stems from the breakthroughs emerging in integrative technologies of genomics and epigenomics and the identification of genetic and epigentic diversity in individual's genetic make-up that are associated with variations in many aspects of health, including diet-related diseases. Microarray is a powerful screen system that is being also currently employed in nutritional research. Monitoring of gene expression at genome level is now possible with this technology, which allows the simultaneous assessment of the transcription of tens of thousands of genes and of their relative expression of pathological cells such tumor cells compared with that of normal cells. Epigenetic events such as DNA methylation can result in change of gene expression without involving changes in gene sequence. Recent developed technology of DNAarray-based methylation assay will facilitate wide study of epigenetic process in nutrigenomics. Some of the areas that would benefitfrom these technologies include identifying molecular targets (Biomarkers) for the risk and benefit assessment. These characterized biomarkers can reflect expose, response, and susceptibility to foods and their components. Furthermore the identified new biomarker perhaps can be utilized as a indicator of delivery system fur optimizing health.

• 한국발생생물학회지:발생과생식
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• 제12권2호
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• pp.117-124
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• 2008

지구상의 모든 생명체들은 자신의 생존과 종의 영속성을 보장하기 위해 우호적이지 않은 환경 변화에 대응하기 위한 효과적인 전략을 발전시켜왔다. 그 결과, 생명체들은 환경요인들의 변화에도 불구하고 체내 생리적 환경의 역동적인 평형, 즉 항상성(homeostasis)을 유지해 나간다. 스트레스는 항상성을 위협하는 정서적 그리고 물리적 반응이다. 스트레스는 일시적일 뿐만 아니라 거의 영구적인 영향을 개체에 줄 수 있는데, 특히 출생전 스트레스는 유전 코드의 변경없이 성체의 기능과 구조를 바꿀 수 있는 '후생학적 프로그래밍'을 할 수 있음이 최근의 연구들에 의해 알려졌다. 본 논문에서는 출생 전 스트레스를 받은 수컷 흰쥐에서 나타나는 생식과 연관된 일련의 사건들, 예를 들어 성적 이형현상을 보이는 뇌 지역의 변화, 신경전달물질 대사의 수정, 생식내분비 상태의 변화, 그리고 마지막으로 성행동의 이상들을 소개한다. 태아의 뇌는 출생전 프로그래밍에 극히 민감한데, 특히 글루코코티코이드는 강력한 뇌-프로그래밍 능력을 갖고 있다. 모체 스트레스에 의해 유도된 글루코코티코이드 입력에 의한 태아 뇌의 지속적인 과도 활성은 신경 가소성을 증가시키는 새로운 프로그램을 제공할 것이다. 그리고 증가한 신경 가소성은 환경 도전 속에서 개체가 더 잘 적응하도록 하는 증가된 표현형의 가소성에 대한 기초가 될 것이다. 결론적으로, '혹독한' 환경을 태아기에 경험한 개체는 미래에 자신의 생존 가능성을 높이기 위해 번식능력을 일부 포기하도록 후생학적으로 (재)프로그램하는 것으로 추정된다.

• 한국발생생물학회지:발생과생식
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• 제15권4호
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• pp.273-279
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• 2011

후성유전학적 조절은 DNA 서열상의 변화 없이도 유전자의 기능을 변화시킬 수 있는 현상을 뜻한다. 염색체의 후성유전학적 상태는 히스톤 변형, DNA 변형 그리고 RNAi에 의한 유전자 침묵 등에 의해 조절된다. 본 총설에서는 배아줄기세포에서의 후성 유전학적 조절에 영향을 주는 요인으로서 히스톤(histone)의 메틸화에 초점을 맞추었다. 배아줄기세포에서 발현되는 유전자의 조절에는 두 가지 단백질 복합체가 관여한다. Polycomb repressive complex 2(PRC2)는 EED, EZH2, SUZ1를 주요인자로 포함하며, H3K27의 trimethylation(H3K27me3)을 증가시킴으로써 유전자의 발현을 억제한다. 이와는 대조적으로 Trithorax group(TrxG) 복합체는 주요인자로 MLL family를 포함하며, H3K4의 trimethylation(H3K4me3) 시킴으로써 유전자의 발현을 활성화한다. PRC2 및 TrxG는 다양한 보조 단백질을 포함한다. 배아줄기세포에서 후성유전학적 조절의 두드러진 특징은 H3K27me3과 H3K4me3이 동시에 나타나는 이가 상태(bivalent state)이다. PRC2와 TrxG 복합체 그리고 H3K4나 K3K27의 메틸화에 특이적으로 작용하는 탈메틸효소(demethylase)가 한데 어우러져 배아줄기세포에서 만능성 관련 유전자와 발달 관련 유전자의 발현을 조절함으로써 줄기세포의 유지 및 분화에 기여한다. 따라서 후성유전학적 조절인자들에 대한 보다 자세한 연구는 배아줄기세포를 보다 잘 이해하고 활용하는데 도움을 줄 것이다.

• 생명과학회지
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• 제28권12호
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• pp.1536-1544
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• 2018

우울증은 심각하며 재발하는 흔한 정신질환이다. 우울증은 환경 요인과 유전 요인, 그리고 신경생물학적 체계의 구조 및 기능의 변화로 발병한다. 후성유전학적 변화가 우울증과 관련 된다는 여러 연구들이 보고되었다. 후성 유전은 환경 요인이 크로마틴 구조를 변화시켜 DNA 염기 서열 변화 없이 유전자 발현을 조절하는 기전으로 설명된다. DNA 메틸화와 히스톤 아세틸화 및 메틸화를 포함하고 있는 히스톤 변형이 주요 후성유전기전으로 알려져 있다. 우울증 동물모델연구에서는 생애 초기 스트레스 같은 스트레스 환경이 게놈에 지속적으로 후성유전표지를 남기게 되고 이로 인해 유전자 발현이 변화되고 결국 성체가 되었을 때 신경 기능이나 행동 기능에 영향을 미치게 된다고 설명하고 있다. BDNF는 우울증과 관련된 대표적인 유전자로 알려져 있다. 설치류가 출생 전, 후, 그리고 성체 기간에 스트레스에 노출되면 해마에서 BDNF 유전자의 히스톤 변형과 DNA 메틸화 패턴이 변화되고 이로 인해 BDNF 발현이 변화된다. 이러한 과정은 불안과 우울 행동에도 영향을 미치게 된다. 본 종설에서는 BDNF 유전자의 히스톤 변형 및 DNA 메틸화와 같은 우울증 발병에 관여하는 후성유전기전의 최신 지견에 대해 논의하여 우울증 치료의 새로운 타겟 개발에 도움이 되고자 한다.

• BMB Reports
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• 제51권5호
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• pp.211-218
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• 2018

Chromatin is an intelligent building block that can express either external or internal needs through structural changes. To date, three methods to change chromatin structure and regulate gene expression have been well-documented: histone modification, histone exchange, and ATP-dependent chromatin remodeling. Recently, a growing body of literature has suggested that histone tail cleavage is related to various cellular processes including stem cell differentiation, osteoclast differentiation, granulocyte differentiation, mammary gland differentiation, viral infection, aging, and yeast sporulation. Although the underlying mechanisms suggesting how histone cleavage affects gene expression in view of chromatin structure are only beginning to be understood, it is clear that this process is a novel transcriptional epigenetic mechanism involving chromatin dynamics. In this review, we describe the functional properties of the known histone tail cleavage with its proteolytic enzymes, discuss how histone cleavage impacts gene expression, and present future directions for this area of study.

• Genomics & Informatics
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• 제13권2호
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• pp.40-44
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• 2015

DNA microarray and next-generation sequencing provide data that can be used for the genetic analysis of multiple quantitative traits such as gene expression levels, transcription factor binding profiles, and epigenetic signatures. In particular, chromatin opening is tightly coupled with gene transcription. To understand how these two processes are genetically regulated and associated with each other, we examined the changes of chromatin accessibility and gene expression in response to genetic variation by means of quantitative trait loci mapping. Regulatory patterns commonly observed in yeast and human across different technical platforms and experimental designs suggest a higher genetic complexity of transcription regulation in contrast to a more robust genetic architecture of chromatin regulation.

• Tuberculosis and Respiratory Diseases
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• 제83권1호
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• pp.1-13
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• 2020

For the past three decades, more than a thousand of genetic studies have been performed to find out the genetic variants responsible for the risk of asthma. Until now, all of the discovered single nucleotide polymorphisms have explained genetic effects less than initially expected. Thus, clarification of environmental factors has been brought up to overcome the 'missing' heritability. The most exciting solution is epigenesis because it intervenes at the junction between the genome and the environment. Epigenesis is an alteration of genetic expression without changes of DNA sequence caused by environmental factors such as nutrients, allergens, cigarette smoke, air pollutants, use of drugs and infectious agents during pre- and post-natal periods and even in adulthood. Three major forms of epigenesis are composed of DNA methylation, histone modifications, and specific microRNA. Recently, several studies have been published on epigenesis in asthma and allergy as a powerful tool for research of genetic heritability in asthma albeit epigenetic changes are at the starting point to obtain the data on specific phenotypes of asthma. In this presentation, we mainly review the potential role of DNA CpG methylation in the risk of asthma and its sub-phenotypes including nonsteroidal anti-inflammatory exacerbated respiratory diseases.

• Journal of Ginseng Research
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• 제42권4호
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• pp.455-462
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• 2018

Background: Ginsenoside Rh2 has been known to enhance the activity of immune cells, as well as to inhibit the growth of tumor cells. Although the repertoire of genes regulated by Rh2 is well-known in many cancer cells, the epigenetic regulation has yet to be determined, especially for comprehensive approaches to detect methylation changes. Methods: The effect of Rh2 on genome-wide DNA methylation changes in breast cancer cells was examined by treating cultured MCF-7 with Rh2. Pyrosequencing analysis was carried out to measure the methylation level of a global methylation marker, LINE1. Genome-wide methylation analysis was carried out to identify epigenetically regulated genes and to elucidate the most prominent signaling pathway affected by Rh2. Apoptosis and proliferation were monitored to examine the cellular effect of Rh2. Results: LINE1 showed induction of hypomethylation at specific CpGs by 1.6-9.1% (p < 0.05). Genome-wide methylation analysis identified the "cell-mediated immune response"-related pathway as the top network. Cell proliferation of MCF-7 was retarded by Rh2 in a dose-dependent manner. Hypermethylated genes such as CASP1, INSL5, and OR52A1 showed downregulation in the Rh2-treated MCF-7, while hypomethylated genes such as CLINT1, ST3GAL4, and C1orf198 showed upregulation. Notably, a higher survival rate was associated with lower expression of INSL5 and OR52A1 in breast cancer patients, while with higher expression of CLINT1. Conclusion: The results indicate that Rh2 induces epigenetic methylation changes in genes involved in immune response and tumorigenesis, thereby contributing to enhanced immunogenicity and inhibiting the growth of cancer cells.

• Asian Pacific Journal of Cancer Prevention
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• 제17권5호
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• pp.2499-2506
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• 2016

Background: Gastric cancer (GC) is the second leading cause of cancer-related death worldwide. Several environmental, genetic and epigenetic factors have been suggested to have a role in GC development. Epigenetic mechanisms like histone changes and promoter hyper-methylation are now being increasingly studied. Associations between methylation of many gene promoters with the risk of gastric cancer have been investigated worldwide. Such aberrant methylation may result in silencing of specific genes related to cell cycling, cell adhesion, apoptosis and DNA repair. Thus this molecular mechanism might have a key role in proliferation and migration of cancerous cells. Materials and Methods: In this review article we included studies conducted on DNA methylation and gastric cancer in Iranian populations. Using Science direct, Pubmed/PMC, Springer, Wiley online library and SciELO databases, all published data until 31 January 2016 were gathered. We also searched Science direct data base for similar investigations around the world to make a comparison between Iran and other countries. Results: By searching these databases, we found that the association between methylation of seven gene promoters and gastric cancer had been studied in Iran until 31 January 2016. These genes were p16, hLMH1, E-cadherin, CTLA4, $THR{\beta}$, mir9 and APC. Searching in science direct database also showed that 92 articles had been published around the world till January 2016. Our investigation revealed that despite the importance of GC and its high prevalence in Iran, the methylation status of only a few gene promoters has been studied so far. More studies with higher sample numbers are needed to reveal the relation of methylation status of gene promoters to gastric cancer in Iran. Conclusions: Further studies will be helpful in identifying associations of DNA methylation in candidate genes with gastric cancer risk in Iranian populations.