Co-targeting RNA Polymerases IV and V Promotes Efficient De Novo DNA Methylation in Arabidopsis.

The RNA-directed DNA methylation (RdDM) pathway in plants controls gene expression via cytosine DNA methylation. The ability to manipulate RdDM would shed light on the mechanisms and applications of DNA methylation to control gene expression. Here, we identified diverse RdDM proteins that are capable of targeting methylation and silencing in Arabidopsis when tethered to an artificial zinc finger (ZF-RdDM). We studied their order of action within the RdDM pathway by testing their ability to target methylation in different mutants. We also evaluated ectopic siRNA biogenesis, RNA polymerase V (Pol V) recruitment, targeted DNA methylation, and gene-expression changes at thousands of ZF-RdDM targets. We found that co-targeting both arms of the RdDM pathway, siRNA biogenesis and Pol V recruitment, dramatically enhanced targeted methylation. This work defines how RdDM components establish DNA methylation and enables new strategies for epigenetic gene regulation via targeted DNA methylation.

Targeted DNA demethylation of the Arabidopsis genome using the human TET1 catalytic domain.

DNA methylation is an important epigenetic modification involved in gene regulation and transposable element silencing. Changes in DNA methylation can be heritable and, thus, can lead to the formation of stable epialleles. A well-characterized example of a stable epiallele in plants is fwa, which consists of the loss of DNA cytosine methylation (5mC) in the promoter of the FLOWERING WAGENINGEN (FWA) gene, causing up-regulation of FWA and a heritable late-flowering phenotype. Here we demonstrate that a fusion between the catalytic domain of the human demethylase TEN-ELEVEN TRANSLOCATION1 (TET1cd) and an artificial zinc finger (ZF) designed to target the FWA promoter can cause highly efficient targeted demethylation, FWA up-regulation, and a heritable late-flowering phenotype. Additional ZF-TET1cd fusions designed to target methylated regions of the CACTA1 transposon also caused targeted demethylation and changes in expression. Finally, we have developed a CRISPR/dCas9-based targeted demethylation system using the TET1cd and a modified SunTag system. Similar to the ZF-TET1cd fusions, the SunTag-TET1cd system is able to target demethylation and activate gene expression when directed to the FWA or CACTA1 loci. Our study provides tools for targeted removal of 5mC at specific loci in the genome with high specificity and minimal off-target effects. These tools provide the opportunity to develop new epialleles for traits of interest, and to reactivate expression of previously silenced genes, transgenes, or transposons.

A brief review: the therapeutic potential of bone marrow mesenchymal stem cells in myocardial infarction.

Myocardial infarction (MI) results in dysfunction and irreversible loss of cardiomyocytes and is among the most serious health threats today. Bone marrow mesenchymal stem cells (BMSCs), with their capacity for multidirectional differentiation, low immunogenicity, and high portability, can serve as ideal seed cells in cardiovascular disease therapy. In this review, we examine recent literature concerning the application of BMSCs for the treatment of MI and consider the following aspects: activity of transplanted cells, migration and homing of BMSCs, immunomodulatory and anti-inflammatory effects of BMSCs, anti-fibrotic activity of BMSCs, the role of BMSCs in angiogenesis, and differentiation of BMSCs into cardiomyocyte-like cells and endothelial cells. Each aspect is complementary to the others and together they promote the repair of cardiomyocytes by BMSCs after MI. Although transplantation of BMSCs has enabled new options for MI treatment, the critical issue we must now address is the reduced viability of transplanted BMSCs due to inadequate blood supply, poor nourishment of cells, and generation of free radicals. More clinical trials are needed to prove the therapeutic potential of BMSCs in MI.

Development of a diagnosis model for coronary artery disease.

BACKGROUND: The purpose of this study was to develop a coronary artery disease (CAD) prediction model that optimally estimates the pre-test probability of CAD for patients suspected of CAD. METHODS AND RESULTS: This retrospective, multi-centre study included 7360 consecutive patients (4678 men, 57.87±11.42 years old; 2682 women, 61.60±9.58 years old) who underwent coronary angiography for evaluation of CAD. A prediction model was fitted for diagnosis of CAD with the help of eight significant risk factors including sex, age, smoking status, diabetes, hypertension, dyslipidaemia, serum creatinine and angina. All potential predictors were significantly associated with the presence of CAD. The prevalence of CAD was significantly higher in men than in women. The clinical model gives a relatively accurate prediction of CAD with an area under the curve (AUC) of 0.74 (95% CI, 0.88-0.96; P<0.001). Addition of angina to the prediction model improves the predictive precision of the model. The optimal cut-off for predicting CAD in this model was 0.79 with a sensitivity of 0.658 and a specificity of 0.709. CONCLUSION: A prediction model including age, sex, and cardiovascular risk factors allow for an accurate estimation of the pre-test probability of coronary artery disease in Chinese populations. This algorithm may be useful in making decisions relating to the diagnosis of CAD.

ABCB1 C3435T polymorphism and the risk of ischemic heart disease: a meta-analysis.

ATP binding cassette transporter 1 (ABCB1) plays a critical role in the development and progression of cardiovascular disease. Emerging evidence suggests that common functional polymorphisms in the ABCB1 gene might have an impact on an individual's susceptibility to ischemic heart disease, but individually published results are inconclusive. The MEDLINE (1966-2013), the Cochrane Library Database (Issue 12, 2013), EMBASE (1980-2013), CINAHL (1982-2013), Web of Science (1945-2013), and the Chinese Biomedical Database (CBM; 1982-2013) were searched without language restrictions. Meta-analysis was performed with the use of the STATA statistical software. Odds ratios (OR) with their 95% confidence intervals (95% CIs) were calculated. Seven case-control studies with a total of 2310 myocardial infarction (MI) patients and 10,506 acute coronary syndrome (ACS) patients met the inclusion criteria. Our meta-analysis results indicated that ABCB1 C3435T polymorphism may be associated with an increased risk of MI and ACS, especially among Asian populations (T allele vs. C allele: OR=1.40, 95% CI=1.31-1.49, ph=0.058). Meta-regression analyses showed that clinical subtype and ethnicity may be the main sources of heterogeneity (T allele vs. C allele: OR=1.16, 95% CI=0.97-1.37, ph=0.036). Our findings provide empirical evidence that ABCB1 C3435T polymorphism may contribute to the risk of MI and ACS, especially among Caucasian populations. Thus, detection of ABCB1 C3435T polymorphism may be a promising biomarker for the early detection of MI and ACS.

Olanzapine is superior to lamotrigine in the prevention of bipolar depression: a naturalistic observational study.

BACKGROUND: Bipolar disorder is a highly recurrent disease and has great impact on the function of patients. Depressive symptoms consist of more than 50% of life time during the illness and may lead to self harm or suicidal behaviors. Little is known about the antidepressant effects of olanzapine, an atypical antipsychotic, as monotherapy despite its indication for preventing manic episodes. In contrast, lamotrigine, a mood stabilizer, has been proven to be effective in preventing depression in patients with bipolar disorder. However, no studies have compared the efficacy between lamotrigine and olanzapine in the maintenance treatment of bipolar disorder. This enriched naturalistic study was implemented to assess the effectiveness of olanzapine and lamotrigine as monotherapy in the prevention of recurrence of bipolar disorder. METHODS: Patients with bipolar disorder in a euthymic state (Young's Mania Rating Scale (YMRS) score <12, and 21-item Hamilton Depression Rating Scale (HAM-D) score <7) for at least two months, having already received either olanzapine or lamotrigine as the maintenance treatment were recruited. The patients maintained with olanzapine (n = 22) were applied to olanzapine group whereas those maintained with lamotrigine (n = 29) were applied to lamotrigine group. They were followed up for 12 months. Differences in the efficacy between olanzapine and lamotrigine in recurrence prevention were analyzed. The Kaplan-Meier method was used to generate time-to-recurrence curves, and differences between the two groups were compared using the log-rank test. RESULTS: Olanzapine had a significantly lower recurrence rate of depressive episodes than lamotrigine (20.0% vs. 57.7%, χ2 = 6.62, p = .010). However, olanzapine and lamotrigine had similar mania (15.0% vs. 0%, χ2 = 4.17, p = .075, Fisher's exact test) and any mood episode (35.0% vs. 57.7%, χ2 = 2.33, p = .127) recurrence rates. Olanzapine was significantly superior to lamotrigine in the time to recurrence of depressive episodes (χ2 = 4.55, df = 1, p = .033), but there was no difference in the time to recurrence of any mood episode (χ2 = 1.68, df = 1, p = .195). CONCLUSIONS: This prospective naturalistic study suggests that olanzapine is more effective than lamotrigine in the prevention of depressive episodes in patients with bipolar disorder. Future large-scale randomized studies are warranted to validate our results. TRIAL REGISTRATION: ClinicalTrials.gov ID NCT01864551.

Seven functional polymorphisms in the CETP gene and myocardial infarction risk: a meta-analysis and meta-regression.

OBJECTIVE: This meta-analysis aims to evaluate the relationships between seven functional polymorphisms in the CETP gene and myocardial infarction (MI) risk. METHOD: The PubMed, CISCOM, CINAHL, Web of Science, Google Scholar, EBSCO, Cochrane Library, and CBM databases were searched for relevant articles published before March 1st, 2013 without any language restrictions. Meta-analysis was conducted using the STATA 12.0 software. RESULTS: Nine case-control studies with a total 8,623 MI cases and 8,564 healthy subjects met the inclusion criteria. The results of our meta-analysis suggested that CETP rs708272 (C>T) polymorphism might be correlated with an increased risk of MI, especially among Caucasians. Furthermore, we observed that CETP rs1800775 (C>A) polymorphism might increase the risk of MI. Nevertheless, no similar findings were found for CETP rs5882 (A>G), rs2303790 (A>G), rs1800776 (C>A), rs12149545 (G>A), and rs4783961 (G>A) polymorphisms. CONCLUSION: The current meta-analysis suggests that CETP rs708272 (C>T) and rs1800775 (C>A) polymorphisms may contribute to MI susceptibility, especially among Caucasians. Thus, CETP rs708272 and rs1800775 polymorphisms may be promising and potential biomarkers for early diagnosis of MI.

ALDH2 rs671 Polymorphism and coronary heart disease risk among Asian populations: a meta-analysis and meta-regression.

Mitochondrial aldehyde dehydrogenase-2 (ALDH2) is the principal enzyme involved in alcohol metabolism in humans. Emerging evidence has shown that the common rs671 G>A (Glu504Lys) polymorphism in the ALDH2 gene might play a critical role in increasing the susceptibility to coronary heart disease (CHD), including myocardial infarction (MI); however, individually published studies showed inconclusive results. This meta-analysis aimed to derive a more precise estimation of the relationship between the ALDH2 rs671 polymorphism and its influence on the susceptibility to CHD and MI. Nine case-control studies were included with a total of 7358 subjects, including 1961 CHD patients, 1040 MI patients, and 4357 healthy controls. Our meta-analysis results showed that the A variant of the ALDH2 rs671 polymorphism may be associated with increase risks of CHD (odds ratios [OR]=1.36, 95% confidence interval [CI]=1.06-1.75, p=0.017) and MI (OR=1.64, 95% CI=1.22-2.20, p=0.001). Univariate and multivariate meta-regression analyses showed no potential factors explained heterogeneity. No publication bias was detected in this meta-analysis. In conclusion, the current meta-analysis indicates that the A variant of the ALDH2 rs671 polymorphism may increase the risk of both CHD and MI among Asian populations.

The rCBF brain mapping in adolescent ADHD comorbid developmental coordination disorder and its changes after MPH challenging.

BACKGROUND: Comorbid developmental coordination disorder (DCD) in the patients with attention-deficit hyperactivity disorder (ADHD) often complicated the treatment strategy. Methylphenidate (MPH) improves the coordination problem in patients with ADHD. AIM: The study intended to investigate the pathophysiology and the mechanisms of MPH in comorbid DCD of the adolescents with ADHD. METHODS: Brain images using technetium-99m ethyl cysteinate dimmer ((99m)Tc-ECD) single photon emission computed tomography (SPECT) were done in 10 drug-naïve adolescents with ADHD without DCD and 5 adolescents with ADHD comorbid DCD. The baseline rCBF and changes of rCBF after 10 mg MPH challenge between two groups were compared using statistical parametric mapping (SPM99) analysis. RESULTS: Lower rCBF of bilateral frontal lobe, inferior parental lobe, and increased rCBF of right posterior cingulate gyrus, anterior lobe of cerebellum were found in ADHD comorbid DCD group compared to ADHD without DCD group. Decreased rCBF in the right occipital, inferior temporal lobe was found in ADHD comorbid DCD group after MPH while ADHD alone group revealed increased rCBF in bilateral occipital lobe. CONCLUSIONS: The results help us understand the pathophysiology of DCD in ADHD adolescents. The different rCBF response to MPH provides a clue for future intervention of DCD in ADHD adolescents.

Spatial characteristics of soil enzyme activities and microbial community structure under different land uses in Chongming Island, China: geostatistical modelling and PCR-RAPD method.

Information about soil enzyme activity and soil DNA as indicators of how land use affects soil quality remains unknown for alluvial island. The purpose of this study was to investigate the effects of land use on enzyme activities and soil gene diversity in the Chongming Island, Shanghai, China, with the aim of providing further knowledge about the problems related to soil quality and its evolving spatial characteristic on the Chongming Island. The results indicate that land use causes an important change of organic matter, with either causing a small decrease or an increase in the absolute enzyme activity. With increased management intensity, there is an increase in the number of soils with high organic matter content and a decrease in the soils with low organic matter content. The effect on enzyme activity varies depending on the type of land use or management and the type of enzyme. The orders of the number of gene polymorphic bands under different land uses were as follows: agriculture soil>commercial soil>industrial soil>wetland. The complexities of the behaviors of the soil enzymes indicate that genetic analysis and biomarkers in conjunction with geostatistics method will be a powerful and accurate indicator to evaluate soil quality under land use.

Bioavailable phosphorus transport from a hillslope cropland of purple soil under natural and simulated rainfall.

To further understand the mechanism of bioavailable total P (BAP) and bioavailable dissolved P (BDP) transport by overland and subsurface flow, we exposed a runoff plot 4.5 m long × 1.5 m wide × 0.6 m deep to simulated and natural rainfall in order to study the effects of rainfall type, rainfall intensity, and vegetation cover on BAP and BDP transport. The results showed that vegetation cover could alleviate the discharge of overland flow and sediment transport and enhance subsurface flow. BAP transport significantly increased with elevated rainfall intensity. Vegetation cover reduced the BAP transport by overland flow and increased it by subsurface flow. BDP transport showed no significant relationship with vegetation cover and rainfall type. The bioavailable particulate P (BPP) transport by overland flow contributed to no less than 90% by weight of total BAP, and the BPP transport by subsurface flow contributed to no less than 60% by weight of total BAP. Short-time heavy rainfall caused more BAP transport and accelerated non-point source pollution.

Variation of natural streamflow since 1470 in the middle Yellow River, China.

Nowadays, as the available water resources throughout the World are becoming depleted, in order to manage and plan water resource better, more and more attention is being paid into the fluctuating characteristics of water discharges. However, the preexisting research was mainly focused on the last half century. In this paper, the natural streamflow observed since 1470 at the Sanmenxia station in the middle Yellow River basin was collected, and the methods of variation coefficient, moving average, Mann-Kendall test and wavelet transform were applied to analyze the dynamic characteristics of the streamflow. The results showed that, (1) between 1470 and 2007, the natural streamflow changed 200-919 x 10(8) m(3), and water discharge varied moderately; (2) in the middle Yellow River basin, it appears that the most severe and most persistent droughts during circa 1868-1990, the periods of 1470s-1490s, 1920s-1930s and 1990s-2000s also presented the condition of sustained low flows; (3) the natural streamflow series shows increasing and decreasing trends during the periods of 1470-1880 and 1881-2007, respectively, but both trends are not significant at >95% confidence; in addition, it is still found the streamflow series shows abrupt changes circa 1845, 1935 and 1960, respectively; (4) within a 250-year scale, there are circa 11, 26, 67 and 120-year periods for natural streamflow at the Sanmenxia station, and the periodicity of the 120-year one is the strongest. The dynamic characteristics of natural streamflow is the comprehensive result by many influencing factors, such as precipitation, temperature, El Niño-Southern Oscillation, sunspots, human activity, etc.

[Fractal characteristics of soil particles in surface layer of black soil].

Based on the second national soil survey of China, the fractal dimension of soil particles in the surface layers of 36 typical profiles of black soil was calculated. The results showed that the fractal dimension was 2.5831-2.8230, being increased with decreasing diameter of soil texture, but the variability was inconspicuous. The fractal dimension was negatively correlated with the contents of sand (2-0.02 mm) and silt (0.02-0.002 mm) (P < 0.05), but positively correlated with clay (< 0.002 mm) content (P < 0.01). No significant correlations were observed between soil particle fractal dimension and soil organic matter, total nitrogen, total phosphorus, total potassium, and pH. The fractal dimension of soil particles could be used as a comprehensive and quantitative index in evaluating the degradation degree of black soil.