Genetic susceptibility in pneumoconiosis in China: a systematic review.

OBJECTIVE: Pneumoconiosis, encompassing coal workers' pneumoconiosis (CWP), silicosis and asbestosis, is one of the most common occupational diseases in China. Previous studies revealed significant associations between genetic variations and pneumoconiosis risk among individuals in different countries. With the known variability of genetic makeup between ethnicities, susceptibility to pneumoconiosis due to genetic differences is likely to be ethnicity-specific. The present review aimed at providing a comprehensive overview on the association between genetic polymorphisms and susceptibility of pneumoconiosis, specifically among people in China. METHODS: The literature search was performed in seven English and Chinese databases using keywords related to the review aim. An appraisal of the methodological quality of the included studies was conducted using the assessment tool derived from the Strengthening the Reporting of Genetic Association Studies (STREGA) statement. RESULTS: Forty-five studies were included in this review. Genotypes of specific genes which are associated with the risk of CWP, silicosis and asbestosis were reported. Our findings showed that genes encoding inflammatory cytokines have been examined extensively, and they demonstrated an association between these genes and pneumoconiosis risk. Gene-environment interactions in pneumoconiosis susceptibility were also reported by a number of studies. CONCLUSIONS: This review summarised the evidence demonstrating the association between genetic polymorphisms and pneumoconiosis susceptibility among people in China, and that various genotypes could modify their risk to develop pneumoconiosis. The findings prompt that identification of individuals at high pneumoconiosis risk through genetic screening and strategies limiting their exposure to dust could be a potential strategy for the control of this occupational disease in China.

Effect of Twinning on Chinese and English Vocabulary Knowledge.

Vocabulary knowledge was tested in a native (Cantonese-Chinese) and foreign (English) language in 150 twins and 150 singletons aged 6-11 years, matched on age, gender, grade level, nonverbal intelligence, parents' education, family income, and number of siblings and household members. The singletons clearly outperformed the twins on the native vocabulary, but this "twinning effect" was much less noticeable for the foreign vocabulary. The effect on English vocabulary was further reduced after exposure to English at home was controlled. Given that these participants learned most of their English in school rather than home, the present findings support the notion that the twinning effect is associated with increased competition for family interaction in twins compared with singletons.

Genomics education in nursing in Hong Kong, Taiwan and Mainland China.

AIM: To identify issues and challenges of genomics education in Hong Kong, Taiwan and Mainland China. BACKGROUND: The use of genetics/genomics in health care, such as genetic testing, pharmacogenomics and tumour profiling in the context of cancer, is increasing. The rapid application of genetics/genomics in clinical practice requires healthcare providers to be competent to practise genetics-related patient care. SOURCES OF EVIDENCE: We reviewed current practices in genomics education in nursing in Hong Kong, Taiwan and Mainland China, including the opportunities for nurses to advance their knowledge and recommendations to incorporate genomics education in the nursing curriculum in these regions. FINDINGS: While many citizens and health professionals recognize the importance of new and exciting research areas of genomics/genetics, there are still many gaps in the translation of genetic/genomic medicine into clinical practice. There is also a similar lack of genetics professionals in China. CONCLUSION: Hong Kong, Taiwan and Mainland China face challenges in promoting genetic education in nursing. A strategic approach in a coordinated effort ineffectively translating genomic knowledge into healthcare practice should be established in these three regions. IMPLICATIONS FOR NURSING AND POLICY: Nursing educators in Hong Kong, Taiwan and Mainland China should link with the international nursing community (e.g. Global Genomics Nursing Alliance) and form closer networks to improve education in the area of genetics and genomics. From a policy level, genomics education is suggested to be incorporated in nursing curriculum to enhance nurses' competency in incorporating genetics/genomics service into patient care.

H19 mediates methotrexate resistance in colorectal cancer through activating Wnt/ß-catenin pathway.

Colorectal cancer (CRC) is a common malignancy, most of which remain unresponsive to chemotherapy. As one of the earliest cytotoxic drugs, methotrexate (MTX) serves as an anti-metabolite and anti-folate chemotherapy for various cancers. Unfortunately, MTX resistance prevents its clinical application in cancer therapy. Thereby, overcoming the drug resistance is an alternative strategy to maximize the therapeutic efficacy of MTX in clinics. Long noncoding RNAs (lncRNAs) have gained widespread attention in recent years. More and more emerging evidences have demonstrated that they play important regulatory roles in various biological activities and disease progression including drug resistance. In the present study, a MTX-resistant colorectal cell line HT-29 (HT-29-R) was developed, which displayed the active proliferation and shortened cell cycle. LncRNA H19 was found to be significantly upregulated in this resistant cell line. Further investigation showed that H19 knockdown sensitized the MTX resistance in HT-29-R cells while its overexpression improved the MTX resistance in the parental cells, suggesting that H19 mediate MTX resistance. The Wnt/ß-catenin signaling was activated in HT-29-R cells, and H19 knockdown suppressed this signaling in the parental cells. In conclusion, H19 mediated MTX resistance via activating Wnt/ß-catenin signaling, which help to develop H19 as a promising therapeutic target for MTX resistant CRC.

CRISPR/Cas9 Technology Targeting Fas Gene Protects Mice From Concanavalin-A Induced Fulminant Hepatic Failure.

Fulminant hepatic failure is a life-threatening disease which occurs in patients without preexisting liver disease. Nowadays, there is no ideal therapeutic tool in the treatment of fulminant hepatic failure. Recent studies suggested that a novel technology termed CRISPR/Cas9 may be a promising approach for the treatment of fulminant hepatic failure. In this project, we have designed single chimeric guide RNAs specifically targeting the genomic regions of mouse Fas gene. The in vitro and in vivo effects of sgRNAs on the production of Fas protein were examined in cultured mouse cells and in a hydrodynamic injection-based mouse model, respectively. The in vivo delivery of CRISPR/Cas9 could maintain liver homeostasis and protect hepatocytes from Fas-mediated cell apoptosis in the fulminant hepatic failure model. Our study indicates the clinical potential of developing the CRISPR/Cas9 system as a novel therapeutic strategy to rescue Concanavalin-A-induced fulminant hepatic failure in the mouse model. J. Cell. Biochem. 118: 530-536, 2017. © 2016 Wiley Periodicals, Inc.

Less is More in Hong Kong: Investigation of Biscriptal and Trilingual Development Among Chinese Twins in a (Relatively) Small City.

One salient characteristic of twin studies and the related behavioral genetics paradigm is the requirement of a large sample size. Countries or regions that are large in size and highly populated are at an advantage when implementing twin studies. However, given the fascinating and promising results obtained from twin studies, many researchers based in smaller countries or regions may still want to conduct twin studies in order to address local and theoretical issues. In this article, we have outlined the development of twin studies in Hong Kong, one of the Special Administrative Regions of China. The historical development and design of the two major twin studies of language and reading development implemented within Hong Kong are discussed, providing insights to researchers who also aspire to conduct twin studies in small regions.

Evaluating Efficacy and Safety of Combination Medication of Atorvastatin and a Herbal Formula Containing Salvia miltiorrhiza and Pueraria lobata on Hyperlipidemia.

Despite being a potent hypolipidemic drug, atorvastatin (AS) possesses certain adverse effects. Using AS and an herbal formula (Danshen and Gegen, DG) in combination may achieve potentiated hypolipidemic effects and also reduce its adverse effects. Hence, this study aimed to investigate the efficacy and safety of an AS and DG combination on high-fat diet-induced hyperlipidemia. Treatment outcomes were assessed by measuring parameters including body weight, adipose tissue, liver, total cholesterol, triglyceride, and low-density and high-density lipoprotein cholesterol. Measurements of adverse effects were achieved by determining aspartate aminotransferase (AST), alanine transaminase (ALT), and creatine kinase (CK). Danshen and Gegen, as well as AS alone, reduced body weight, adipose tissue, liver weight, liver fat vacuoles, total liver lipids, total cholesterol, triglyceride, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol in high-fat diet-fed mice but increased AST, ALT, and CK. A combination of AS and DG was able to enhance reduced effects on the aforementioned parameters in relation to hyperlipidemia over AS or DG alone. It also reduced the elevation of AST, ALT, and CK induced than by AS or DG alone. Results demonstrated that an AS and DG combination resulted in stronger hypolipidemic effects than with AS or DG alone. Additionally, DG might attenuate adverse effects of AS on the liver and skeletal muscle. Copyright © 2017 John Wiley & Sons, Ltd.

MiR-218 mediates tumorigenesis and metastasis: Perspectives and implications.

MicroRNAs (miRNAs) are a class of small non-coding RNAs that negatively regulate gene expression at the post-transcriptional level. As a highly conserved miRNA across a variety of species, microRNA-218 (miR-218) was found to play pivotal roles in tumorigenesis and progression. A group of evidence has demonstrated that miR-218 acts as a tumor suppressor by targeting many oncogenes related to proliferation, apoptosis and invasion. In this review, we provide a complex overview of miR-218, including its regulatory mechanisms, known functions in cancer and future challenges as a potential therapeutic target in human cancers.

MiR-25 suppresses 3T3-L1 adipogenesis by directly targeting KLF4 and C/EBPα.

In the past decade, miRNA emerges as a vital player in orchestrating gene regulation and maintaining cellular homeostasis. It is well documented that miRNA influences a variety of biological events, including embryogenesis, cell fate decision, and cellular differentiation. Adipogenesis is an organized process of cellular differentiation by which pre-adipocytes differentiate towards mature adipocytes. It has been shown that adipogenesis is tightly modulated by a number of transcription factors such as PPARγ, KLF4, and C/EBPα. However, the molecular mechanisms underlying the missing link between miRNA and adipogenesis-related transcription factors remain elusive. In this study, we unveiled that miR-25, a member of miR-106b-25 cluster, was remarkably downregulated during 3T3-L1 adipogenesis. Restored expression of miR-25 significantly impaired 3T3-L1 adipogenesis and downregulated the expression of serial adipogenesis-related genes. Further experiments presented that ectopic expression of miR-25 did not affect cell proliferation and cell cycle progression. Finally, KLF4 and C/EBPα, two key regulators of adipocyte differentiation, were experimentally identified as bona fide targets for miR-25. These data indicate that miR-25 is a novel negative regulator of adipocyte differentiation and it suppressed 3T3-L1 adipogenesis by targeting KLF4 and C/EBPα, which provides novel insights into the molecular mechanism of miRNA-mediated cellular differentiation.

Hotair mediates hepatocarcinogenesis through suppressing miRNA-218 expression and activating P14 and P16 signaling.

BACKGROUND & AIMS: Long non-coding RNA Hotair has been considered as a pro-oncogene in multiple cancers. Although there is emerging evidence that reveals its biological function and the association with clinical prognosis, the precise mechanism remains largely elusive. METHODS: We investigated the function and mechanism of Hotair in hepatocellular carcinoma (HCC) cell models and a xenograft mouse model. The regulatory network between miR-218 and Hotair was elucidated by RNA immunoprecipitation and luciferase reporter assays. Finally, the correlation between Hotair, miR-218 and the target gene Bmi-1 were evaluated in 52 paired HCC specimens. RESULTS: In this study, we reported that Hotair negatively regulated miR-218 expression in HCC, which might be mediated through an EZH2-targeting-miR-218-2 promoter regulatory axis. Further investigation revealed that Hotair knockdown dramatically inhibited cell viability and induced G1-phase arrest in vitro and suppressed tumorigenicity in vivo by promoting miR-218 expression. Oncogene Bmi-1 was shown to be a functional target of miR-218, and the main downstream targets signaling, P16(Ink4a) and P14(ARF), were activated in Hotair-suppressed tumorigenesis. In primary human HCC specimens, Hotair and Bmi-1 were concordantly upregulated whereas miR-218 was downregulated in these tissues. Furthermore, Hotair was inversely associated with miR-218 expression and positively correlated with Bmi-1 expression in these clinical tissues. CONCLUSION: Hotair silence activates P16(Ink4a) and P14(ARF) signaling by enhancing miR-218 expression and suppressing Bmi-1 expression, resulting in the suppression of tumorigenesis in HCC.

Identification of miRNAs that specifically target tumor suppressive KLF6-FL rather than oncogenic KLF6-SV1 isoform.

The Krüppel like factor 6 (KLF6) gene encodes multiple protein isoforms derived from alternative mRNA splicing, most of which are intimately involved in hepatocarcinogenesis and tumor progression. Recent bioinformatics analysis shows that alternative mRNA splicing of the KLF6 gene produces around 16 alternatively spliced variants with divergent or even opposing functions. Intriguingly, the full-length KLF6 (KLF6-FL) is a tumor suppressor gene frequently inactivated in liver cancer, whereas KLF6 splice variant 1 (KLF6-SV1) is an oncogenic isoform with antagonistic function against KLF6-FL. Compelling evidence indicates that miRNA, the small endogenous non-coding RNA (ncRNA), acts as a vital player in modulating a variety of cellular biological processes through targeting different mRNA regions of protein-coding genes. To identify the potential miRNAs specifically targeting KLF6-FL, we utilized bioinformatics analysis in combination with the luciferase reporter assays and screened out two miRNAs, namely miR-210 and miR-1301, specifically targeted the tumor suppressive KLF6-FL rather than the oncogenic KLF6-SV1. Our in vitro experiments demonstrated that stable expression of KLF6-FL inhibited cell proliferation, migration and angiogenesis while overexpression of miR-1301 promoted cell migration and angiogenesis. Further experiments demonstrated that miR-1301 was highly expressed in liver cancer cell lines as well as clinical specimens and we also identified the potential methylation and histone acetylation for miR-1301 gene. To sum up, our findings unveiled a novel molecular mechanism that specific miRNAs promoted tumorigenesis by targeting the tumor suppressive isoform KLF6-FL rather than its oncogenic isoform KLF6-SV1.

Structural Variations Identified in Patients with Autism Spectrum Disorder (ASD) in the Chinese Population: A Systematic Review of Case-Control Studies.

Autistic spectrum disorder (ASD) is a neurodevelopmental disability characterised by the impairment of social interaction and communication ability. The alarming increase in its prevalence in children urged researchers to obtain a better understanding of the causes of this disease. Genetic factors are considered to be crucial, as ASD has a tendency to run in families. In recent years, with technological advances, the importance of structural variations (SVs) in ASD began to emerge. Most of these studies, however, focus on the Caucasian population. As a populated ethnicity, ASD shall be a significant health issue in China. This systematic review aims to summarise current case-control studies of SVs associated with ASD in the Chinese population. A list of genes identified in the nine included studies is provided. It also reveals that similar research focusing on other genetic backgrounds is demanded to manifest the disease etiology in different ethnic groups, and assist the development of accurate ethnic-oriented genetic diagnosis.

Intervention Efficacy of Slightly Processed Allergen/Meat in Oral Immunotherapy for Seafood Allergy: A Systematic Review, Meta-Analysis, and Meta-Regression Analysis in Mouse Models and Clinical Patients.

Background: Seafood allergy is a significant global health concern that greatly impacts a patient's quality of life. The intervention efficacy of oral immunotherapy (OIT), an emerging intervention strategy, for seafood allergy remains controversial. This study aimed to perform a systematic review and meta-analysis to evaluate the efficacy of slightly processed allergen/meat from fish and crustacea in OIT, both in mouse models and clinical patients. Methods: A comprehensive literature search was performed in four mainstream databases and the EBSCOhost database to identify all relevant case-control and cohort studies. The aim was to elucidate the intervention efficacy, encompassing various processing methods and assessing the efficacy of multiple major allergens in OIT. Results: The meta-analysis included five case-control studies on crustacean allergens in mouse models and 11 cohort studies on meat from fish and crustacea in clinical patients for final quantitative assessments. In mouse models, crustacean allergen substantially decreased the anaphylactic score after OIT treatment (mean difference (MD) = -1.30, p < 0.01). Subgroup analyses with low-level heterogeneities provided more reliable results for crab species (MD = -0.63, p < 0.01, I2 = 0), arginine kinase allergen (MD = -0.83, p < 0.01, I2 = 0), and Maillard reaction processing method (MD = -0.65, p < 0.01, I2 = 29%), respectively. In clinical patients, the main meta-analysis showed that the slightly processed meat significantly increased the incidence rate of oral tolerance (OT, incidence rate ratio (IRR) = 2.90, p < 0.01). Subgroup analyses for fish meat (IRR = 2.79, p < 0.01) and a simple cooking treatment (IRR = 2.36, p = 0.01) also demonstrated a substantial increase in the incidence rate of OT. Sensitivity and meta-regression analyses successfully identified specific studies contributing to heterogeneity in mouse models and clinical patients, although these studies did not impact the overall significant pooled effects. Conclusions: This meta-analysis provides preliminary evidence for the high intervention efficacy of slightly processed allergen/meat from fish and crustacea in OIT, both in mouse models and clinical patients. The Maillard reaction and cooking processing methods may emerge as potentially effective approaches to treating allergen/meat in OIT for clinical patients, offering a promising and specific treatment strategy for seafood allergy. However, these findings should be interpreted cautiously, and further supporting evidence is necessary.

Characterization of miR-210 in 3T3-L1 adipogenesis.

Although accumulating evidences indicate that miRNA emerge as a vital player in cell growth, development, and differentiation, how they contribute to the process of adipocyte differentiation remains elusive. In the present study, we revealed that the expression level of miR-210 was dramatically upregulated during 3T3-L1 adipogenesis. Ectopic introduction of miR-210 into 3T3-L1 cells promoted terminal differentiation as well as the expression of adipogenic markers. MTT assay showed that miR-210 significantly inhibited cell proliferation whereas the BrdU incorporation assay and flow cytometry analysis showed that miR-210 did not impair G1/S phase transition. Further experiments demonstrated that enhanced expression of miR-210 in 3T3-L1 cells provoked adipocyte differentiation via activation of PI3K/Akt pathway by targeting SHIP1, a negative regulator of PI3K/Akt pathway. Moreover, blockade of endogenous miR-210 during adipogenesis significantly repressed adipocyte differentiation. In summary, we have identified miR-210 as an important positive regulator in adipocyte differentiation through the activation of PI3K/Akt pathway.

Nursing students' perceived anxiety and heart rate variability in mock skill competency assessment.

BACKGROUND: Skill competency assessments induce stress and anxiety and may affect nursing student performance. Little is known about stress and perceived anxiety levels and their relationship in the mock skill competency assessment. METHODS: A cross-sectional study was conducted to examine the stress levels (as assessed by heart rate variability, HRV) and perceived anxiety before, during and after the mock skill competency assessment, and to explore their relationships to performance in a total of ninety first-year undergraduate nursing students. RESULTS: The HRV decreased significantly during the assessment and increased significantly 10 min after the assessment (p < 0.01). Higher performers showed significantly lower HRV during and after the assessment (p < 0.01). The assessment score was negatively correlated with HRV during and after the assessment (p < 0.05). CONCLUSIONS: Considering assessment-related stress and anxiety through a mock assessment prior to the actual skill assessment provides implications for future nursing education.

A Positive Causal Effect of Shrimp Allergy on Major Depressive Disorder Mediated by Allergy- and Immune-Related Pathways in the East Asian Population.

BACKGROUND: Observational studies have implied a potential correlation between allergic diseases and major depressive disorder (MDD). However, the relationship is still inconclusive as it is likely to be interfered with by substantial confounding factors and potential reverse causality. The present study aimed to investigate causal correlation of the two diseases by a Mendelian randomization (MR) study and further elucidate the underlying molecular mechanisms. METHODS: With the biggest summary datasets of a genome-wide association study (GWAS) in the East Asian population, we conducted a two-sample, bidirectional MR study to assess the causal correlation between shrimp allergy (SA) and MDD. Subsequently, we identified the pleiotropic genes' susceptibility to the two diseases at whole-genome and tissue-specific levels, respectively. Enriched GO sets and KEGG pathways were also discovered to elucidate the potential underlying mechanisms. RESULTS: With the most suitable MR method, SA was identified as a causal risk factor for MDD based on three different groups of independent genetic instruments, respectively (p < 2.81 × 10-2). In contrast, we did not observe a significant causal effect of MDD on SA. The GWAS-pairwise program successfully identified seven pleiotropic genetic variants (PPA3 > 0.8), indicating that the two diseases indeed have a shared genetic basis. At a whole-genome level, the MAGMA program identified 44 pleiotropic genes, which were enriched in allergy-related pathways, such as antigen processing and presentation pathway (p = 1.46 × 10-2). In brain-specific tissue, the S-MultiXcan program found 17 pleiotropic genes that were significantly enriched in immune-related pathways and GO sets, including asthma-related pathway, T-cell activation-related, and major histocompatibility complex protein-related GO sets. Regarding whole-blood tissue, the program identified six pleiotropic genes that are significantly enriched in tolerance induction-related GO sets. CONCLUSIONS: The present study for the first time indicated a significant causal effect of SA on the occurrence of MDD, but the reverse was not true. Enrichment analyses of pleiotropic genes at whole-genome and tissue-specific levels implied the involvement of allergy and immune-related pathways in the shared genetic mechanism of the two diseases. Elucidating the causal effect and the acting direction may be beneficial in reducing the incidence rate of MDD for the massive group of SA patients in the East Asian region.

Dyslexia-associated kiaa0319-like protein interacts with axon guidance receptor nogo receptor 1.

To identify the putative interacting partners for Kiaa0319-like protein. KIAA0319-like, located near the dyslexia susceptibility locus, DYX8 in chromosome 1p34.3, has been suggested as a positional candidate for developmental dyslexia due to its homology with another gene, KIAA0319 which has been strongly established as a candidate gene for developmental dyslexia. Previous research has shown that a single marker, rs7523017 (P = 0.042) has been associated with developmental dyslexia by a Canadian group. There is little functional information about this gene and protein. In this article, we put forward further evidence that support Kiaa0319-like is a candidate for this disorder. A yeast-2-hybrid screen and co-immunopreciptiation assays were performed to find protein interacting partners of KIAA0319L. A human cortex immunohistochemistry assay was performed to show the colocalization of Kiaa0319-like and its specific interacting partner in cells. Nogo Receptor 1 (NgR1), an axon guidance receptor, was identified to have physical interactions with Kiaa0319-like protein. These two proteins interact predominantly in the cytoplasmic granules of cortical neurons in the human brain cortex. Based on this data, it can be concluded that Kiaa0319-like protein interacts with Nogo Receptor 1, supporting the idea that Kiaa0319-like protein participates in axon guidance.

Autophagy signals orchestrate chemoresistance of gynecological cancers.

Gynecological cancers are characterized by a high mortality rate when chemoresistance develops. Autophagy collaborates with apoptosis and participates in homeostasis of chemoresistance. Recent findings supported that crosstalk of necrotic, apoptotic and autophagic factors, and chemotherapy-driven hypoxia, oxidative stress and ER stress play critical roles in chemoresistance in gynecological cancers. Meanwhile, current studies have shown that autophagy could be regulated by and cooperate with metabolic regulator, survival factors, stemness factors and specific post-translation modification in chemoresistant tumor cells. Meanwhile, non-coding RNA and autophagy crosstalk also contribute to the chemoresistance. Until now, analysis of individual autophagy factors towards the clinical significance and chemoresistance in gynecological cancer is still lacking. We suggest comprehensive integrated analysis of cellular homeostasis and tumor microenvironment to clarify the role of autophagy and the associated factors in cancer progression and chemoresistance. Panel screening of pan-autophagic factors will pioneer the development of risk models for predicting efficacy of chemotherapy and guidelines for systematic treatment and precision medicine.

Exploration of Potential Genetic Biomarkers for Heart Failure: A Systematic Review.

Patients with heart failure (HF) often present with signs and symptoms that are often nonspecific and with a wide differential diagnosis, making diagnosis and prognosis of HF by clinical presentation alone challenging. Our knowledge on genetic diversity is rapidly evolving with high-throughput DNA sequencing technology, which makes a great potential for genetic biomarker development. The present review attempts to provide a comprehensive review on the modification of major genetic components in HF patients and to explore the potential application of these components as clinical biomarkers in the diagnosis and in monitoring the progress of HF. The literature search was conducted using six databases, resulting in the inclusion of eighteen studies in the review. The findings of these studies were summarized narratively. An appraisal of the reporting quality of the included studies was conducted using a twelve-item checklist adapted from the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist. The findings showed that changes in genetic components in patients with HF compared to healthy controls could be noninvasive diagnostic or prognostic tools for HF with higher specificity and sensitivity in comparison with the traditional biomarkers. This review provided evidence for the potential of developing genetic biomarkers of HF.

Epigenetic regulation of neonatal cardiomyocytes differentiation.

The relationship between DNA methylation, histone modifications and terminal differentiation in cardiomyocytes was investigated in this study. The upregulation of methylation-related proteins, including DNA methyltransferase (DNMT) 1, methyl-CpG binding domain proteins 1, 2 and 3, and the increase in global methylation during rat neonatal heart development were observed. Moreover, an increase in DNA synthesis and a delay in differentiation were found in 5-azacytidine (5-azaC)-treated cardiomyocytes. Increase in acetylation of H3-K9, H4-K5, H4-K8 and methylation of H3-K4 suggested a more accessible chromatin structure in 5-azaC-treated cells. Furthermore, methyl-CpG-binding protein 2 was found to be upregulated in differentiated cardiomyocytes. Overexpression of this protein resulted in an increase of global methylation levels. Therefore, we suggest that a hypermethylated genome and a more compact chromatin structure are formed during terminal differentiation of cardiomyocytes.