Genetic enrichment of cardiomyocytes derived from mouse embryonic stem cells

Pluripotent embryonic stem cells (ESC) have the ability to differentiate into a variety of cell lineages in vitro, including cardiomyocytes. Successful applications of ESC-derived cardiomyocytes in cell therapy and tissue engineering were limited by difficulties in selecting the desired cells from the heterogeneous cell population. We describe a simple method to generate relatively pure cardiomyocytes from mouse ESCs. A construct comprising mouse cardiac α-myosin heavy chain (MHC) promoter driving the neomycin resistance gene and SV40 promoter driving the hygromycin resistant gene designated pMHCneo/ SV40-hygro, was stably transfected into mouse ESCs. The transgenic ESC line, designated MN6 retained the undifferentiated state and the potential of cardiogenic differentiation. After G418 selection, more than 99% of cells expressed α-sarcomeric actin. Immunocytological and ultrastructural analysis demonstrated that, the selected cardiomyocytes were highly differentiated. Our results represent a simple genetic manipulation used to product essentially pure cardiomyocytes from differentiating ESCs. It may facilitate the development of cell therapy in heart diseases.Key words: Embryonic stem cells, α-myosin heavy chain promoter, cardiomyocytes, differentiation, genetic enrichment

Polypyrrole-Fe2O3 nanohybrid materials for electrochemical storage

We report on the synthesis and electrochemical characterization of nanohybrid polypyrrole (PPy) (PPy/Fe2O3) materials for electrochemical storage applications. We have shown that the incorporation of nanoparticles inside the PPy notably increases the charge storage capability in comparison to the “pure” conducting polymer. Incorporation of large anions, i.e., paratoluenesulfonate, allows a further improvement in the capacity. These charge storage modifications have been attributed to the morphology of the composite in which the particle sizes and the specific surface area are modified with the incorporation of nanoparticles. High capacity and stability have been obtained in PC/NEt4BF4 (at 20 mV/s), i.e., 47 mAh/g, with only a 3% charge loss after one thousand cyles. The kinetics of charge–discharge is also improved by the hybrid nanocomposite morphology modifications, which increase the rate of insertion–expulsion of counter anions in the bulk of the film. A room temperature ionic liquid such as imidazolium trifluoromethanesulfonimide seems to be a promising electrolyte because it further increases the capacity up to 53 mAh/g with a high stability during charge–discharge processes

ER Stress Negatively Modulates the Expression of the miR-199a/214 Cluster to Regulates Tumor Survival and Progression in Human Hepatocellular Cancer

Background: Recent studies have emphasized causative links between microRNAs (miRNAs) deregulation and tumor development. In hepatocellular carcinoma (HCC), more and more miRNAs were identified as diagnostic and prognostic cancer biomarkers, as well as additional therapeutic tools. This study aimed to investigate the functional significance and regulatory mechanism of the miR-199a2/214 cluster in HCC progression. Methods and Findings: In this study, we showed that miR-214, as well as miR-199a-3p and miR-199a-5p levels were significantly reduced in the majority of examined 23 HCC tissues and HepG2 and SMMC-7721 cell lines, compared with their nontumor counterparts. To further explore the role of miR-214 in hepatocarcinogenesis, we disclosed that the ER stressinduced pro-survival factor XBP-1 is a target of miR-214 by using western blot assay and luciferase reporter assay. Reexpression of miR-214 in HCC cell lines (HepG2 and SMMC-7721) inhibited proliferation and induced apoptosis. Furthermore, ectopic expression of miR-214 dramatically suppressed the ability of HCC cells to form colonies in vitro and to develop tumors in a subcutaneous xenotransplantation model of the BALB/c athymic nude mice. Moreover, reintroduction of XBP-1s attenuated miR-214-mediated suppression of HCC cells proliferation, colony and tumor formation. To further understand the mechanism of the miR-199a/214 cluster down-expression in HCC, we found that thapsigargin (TG) and tunicamycin (TM) or hypoxia-induced unfolded protein response (UPR) suppresses the expression of the miR-199a/21

Observation of a ppb mass threshoud enhancement in \psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) decay

The decay channel $\psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p})$ is studied using a sample of $1.06\times 10^8$ $\psi^\prime$ events collected by the BESIII experiment at BEPCII. A strong enhancement at threshold is observed in the $p\bar{p}$ invariant mass spectrum. The enhancement can be fit with an $S$-wave Breit-Wigner resonance function with a resulting peak mass of $M=1861^{+6}_{-13} {\rm (stat)}^{+7}_{-26} {\rm (syst)} {\rm MeV/}c^2$ and a narrow width that is $\Gamma<38 {\rm MeV/}c^2$ at the 90% confidence level. These results are consistent with published BESII results. These mass and width values do not match with those of any known meson resonance.Comment: 5 pages, 3 figures, submitted to Chinese Physics

NF-κB inhibition impairs the radioresponse of hypoxic EMT-6 tumour cells through downregulation of inducible nitric oxide synthase

Hypoxic EMT-6 tumour cells displayed a high level of inducible nitric oxide synthase (iNOS) and an increased radiosensitivity after a 16 h exposure to lipopolysaccharide, a known activator of nuclear factor-κB (NF-κB). Both iNOS activation and radioresponse were impaired by the NF-κB inhibitors phenylarsine oxide and lactacystin. Contrasting to other studies, our data show that inhibition of NF-κB may impair the radioresponse of tumour cells through downregulation of iNOS. © 2003 Cancer Research UK.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

A novel class of heat-responsive small RNAs derived from the chloroplast genome of Chinese cabbage (Brassica rapa)

<p>Abstract</p> <p>Background</p> <p>Non-coding small RNAs play critical roles in various cellular processes in a wide spectrum of eukaryotic organisms. Their responses to abiotic stress have become a popular topic of economic and scientific importance in biological research. Several studies in recent years have reported a small number of non-coding small RNAs that map to chloroplast genomes. However, it remains uncertain whether small RNAs are generated from chloroplast genome and how they respond to environmental stress, such as high temperature. Chinese cabbage is an important vegetable crop, and heat stress usually causes great losses in yields and quality. Under heat stress, the leaves become etiolated due to the disruption and disassembly of chloroplasts. In an attempt to determine the heat-responsive small RNAs in chloroplast genome of Chinese cabbage, we carried out deep sequencing, using heat-treated samples, and analysed the proportion of small RNAs that were matched to chloroplast genome.</p> <p>Results</p> <p>Deep sequencing provided evidence that a novel subset of small RNAs were derived from the chloroplast genome of Chinese cabbage. The chloroplast small RNAs (csRNAs) include those derived from mRNA, rRNA, tRNA and intergenic RNA. The rRNA-derived csRNAs were preferentially located at the 3'-ends of the rRNAs, while the tRNA-derived csRNAs were mainly located at 5'-termini of the tRNAs. After heat treatment, the abundance of csRNAs decreased in seedlings, except those of 24 nt in length. The novel heat-responsive csRNAs and their locations in the chloroplast were verified by Northern blotting. The regulation of some csRNAs to the putative target genes were identified by real-time PCR. Our results reveal that high temperature suppresses the production of some csRNAs, which have potential roles in transcriptional or post-transcriptional regulation.</p> <p>Conclusions</p> <p>In addition to nucleus, the chloroplast is another important organelle that generates a number of small RNAs. Many members of csRNA families are highly sensitive to heat stress. Some csRNAs respond to heat stress by silencing target genes. We suggest that proper temperature is important for production of chloroplast small RNAs, which are associated with plant resistance to abiotic stress.</p

Mycobacterium marinum antagonistically induces an autophagic response while repressing the autophagic flux in a TORC1- and ESX-1-dependent manner.

Autophagy is a eukaryotic catabolic process also participating in cell-autonomous defence. Infected host cells generate double-membrane autophagosomes that mature in autolysosomes to engulf, kill and digest cytoplasmic pathogens. However, several bacteria subvert autophagy and benefit from its machinery and functions. Monitoring infection stages by genetics, pharmacology and microscopy, we demonstrate that the ESX-1 secretion system of Mycobacterium marinum, a close relative to M. tuberculosis, upregulates the transcription of autophagy genes, and stimulates autophagosome formation and recruitment to the mycobacteria-containing vacuole (MCV) in the host model organism Dictyostelium. Antagonistically, ESX-1 is also essential to block the autophagic flux and deplete the MCV of proteolytic activity. Activators of the TORC1 complex localize to the MCV in an ESX-1-dependent manner, suggesting an important role in the manipulation of autophagy by mycobacteria. Our findings suggest that the infection by M. marinum activates an autophagic response that is simultaneously repressed and exploited by the bacterium to support its survival inside the MCV