Chelativorans salis sp. nov., a slightly halophilic bacterium isolated from an enrichment system with saline lake sediment.

A Gram-stain-negative, non-motile, and slightly halophilic alphaproteobacterium, designated strain EGI FJ00035T, was isolated from enrichment sediment samples of a saline lake in Xinjiang Uygur Autonomous Region, PR China. The taxonomic position of the isolate was determined using the polyphasic taxonomic and phylogenomic analyses. Phylogenetic analysis based on the 16S rRNA gene sequences indicated that strain EGI FJ00035T formed a distinct clade with 'Chelativorans alearense' UJN715 and 'Chelativorans xinjiangense' lm93 with sequence similarities of 98.44 and 98.22 %, respectively, while sharing less than 96.7 % with other valid type strains. The novel isolate could be distinguished from other species of the genus Chelativorans by its distinct phenotypic, physiological, and genotypic characteristics. Optimal growth of strain EGI FJ00035T occurred on marine agar 2216 at pH 7.0 and 30 °C. The major respiratory quinone was Q-10, while the major fatty acids (>5 %) were C19 : 0 cyclo ω8c, summed feature 8 (C17 : 1 ω6c and/or C17 : 1 ω7c), C16 : 0, C18 : 0, and iso-C17 : 0. The detected polar lipids included diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, unidentified aminophospholipids, unidentified glycolipids, and an unidentified lipid. Based on its genome sequence, the G+C content of strain EGI FJ00035T was 63.2 mol%. The average nucleotide identity, average amino acid identity, and digital DNA-DNA hybridization values of strain EGI FJ00035T against related members of the genus Chelativorans were below the thresholds for delineation of a novel species. According our polyphasic taxonomic data, strain EGI FJ00035T represents a new species of the genus Chelativorans, for which the name Chelativorans salis sp. nov. is proposed. The type strain of the proposed novel isolate is EGI FJ00035T (=KCTC 92251T=CGMCC 1.19480T).

Cardioprotection of post-ischemic moderate ROS against ischemia/reperfusion via STAT3-induced the inhibition of MCU opening.

Enhanced reactive oxygen species (ROS) at the beginning of reperfusion activated signal transducer and activator of transcription 3 (STAT3) in intermittent hypobaric hypoxia (IHH)-afforded cardioprotection against ischemia/reperfusion (I/R). However, its mechanism remains largely unknown. This study aimed to investigate the role and the downstream of STAT3 in exogenous enhanced post-ischemic ROS-induced cardioprotection using the model of moderate hydrogen peroxide postconditioning (H2O2PoC) mimicking endogenous ROS in IHH. Moderate H2O2PoC not only improved the post-ischemic myocardial contractile recovery and reduced the infarct size in isolated rat I/R hearts, but also alleviated mitochondrial calcium overload and ameliorated Ca2+ transients, cell contraction, and mitochondrial membrane potential in rat I/R cardiomyocytes. However, the cardioprotective effects of moderate H2O2PoC were abrogated by Janus kinase 2 (JAK2)/STAT3 inhibitor AG490 in rat hearts as well as adenovirus-delivered short hairpin RNA specific for STAT3 and the opener of mitochondrial calcium uniporter (MCU) spermine in rat cardiomyocytes. Notably, the moderate H2O2PoC-afforded cardioprotection abrogated by spermine could be rescued by STAT3 over-expression with adenovirus in rat I/R cardiomyocytes. Besides, moderate H2O2PoC enhanced mitochondrial STAT3 expression during I/R. A co-localization/interaction of STAT3 or phospho-STAT3ser727 and MCU was observed in rat cardiomyocytes with moderate H2O2PoC at 5 and 30 min of reperfusion but not in rat I/R cardiomyocytes. Further, STAT3 interacted with the N-terminal domain (NTD) of MCU in rat cardiomyocytes with moderate H2O2PoC. These findings indicated that post-ischemic moderate ROS activate STAT3 against cardiac I/R by inhibiting MCU opening via its interaction with the NTD of MCU to alleviate mitochondrial calcium overload.

Temporal dynamics of immune response following prolonged myocardial ischemia/reperfusion with and without cyclosporine A.

Understanding the dynamics of the immune response following late myocardial reperfusion is critical for the development of immunomodulatory therapy for myocardial infarction (MI). Cyclosporine A (CSA) possesses multiple therapeutic applications for MI, but its effects on the inflammation caused by acute MI are not clear. This study aimed to determine the dynamics of the immune response following myocardial ischemia/reperfusion (I/R) and the effects of CSA in a mouse model of prolonged myocardial ischemia designated to represent the human condition of late reperfusion. Adult C57BL/6 mice were subjected to 90 min of closed-chest myocardial I/R, which induced severe myocardial injury and excessive inflammation in the heart. Multicomponent analysis of the immune response caused by prolonged I/R revealed that the peak of cytokines/chemokines in the systemic circulation was synchronized with the maximal influx of neutrophils and T-cells in the heart 1 day after MI. The peak of cytokine/chemokine secretion in the infarcted heart coincided with the maximal macrophage and natural killer cell infiltration on day 3 after MI. The cellular composition of the mediastinal lymph nodes changed similarly to that of the infarcted hearts. CSA (10 mg/kg/day) given after prolonged I/R impaired heart function, enlarged the resulting scar, and reduced heart vascularization. It did not change the content of immune cells in hearts exposed to prolonged I/R, but the levels of MCP-1 and MIP-1α (hearts) and IL-12 (hearts and serum) were significantly reduced in the CSA-treated group in comparison to the untreated group, indicating alterations in immune cell function. Our findings provide new knowledge necessary for the development of immunomodulatory therapy targeting the immune response after prolonged myocardial ischemia/reperfusion.

miR-142-3p Contributes to Early Cardiac Fate Decision of Embryonic Stem Cells.

MicroRNAs (miRNAs) play important roles in cell fate decisions. However, the miRNAs and their targets involved in the regulation of cardiac lineage specification are largely unexplored. Here, we report novel functions of miR-142-3p in the regulation of cardiomyocyte differentiation from mouse embryonic stem cells (mESCs). With a miRNA array screen, we identified a number of miRNAs significantly changed during mESC differentiation into the mesodermal and cardiac progenitor cells, and miR-142-3p was one among the markedly downregulated miRNAs. Ectopic expression and inhibition of miR-142-3p did not alter the characteristics of undifferentiated ESCs, whereas ectopic expression of miR-142-3p impaired cardiomyocyte formation. In addition, ectopic expression of miR-142-3p inhibited the expression of a cardiac mesodermal marker gene Mesp1 and downstream cardiac transcription factors Nkx2.5, Tbx5, and Mef2c but not the expression of three germ layer-specific genes. We further demonstrated that miR-142-3p targeted the 3'-untranslated region of Mef2c. These results reveal miR-142-3p as an important regulator of early cardiomyocyte differentiation. Our findings provide new knowledge for further understanding of roles and mechanisms of miRNAs as critical regulators of cardiomyocyte differentiation.

[Expression profile of microRNAs in the cardiomyocytes derived from mouse embryonic stem cells].

Embryonic stem cells (ESCs), derived from the inner cell mass of blastocysts, are self-renewing and pluripotent cells with the ability to differentiate into all derivatives of three primary germ layers, including cardiomyocytes. Recent studies have revealed that posttranscriptional regulations of lineage specific genes by microRNAs (miRNAs) emerge as a new class of cell fate and lineage determinants of ESCs. However, the miRNAs that control ESC differentiation are still largely unexplored. In the present study, we aimed to identify miRNAs that might be involved in cardiac differentiation of ESCs. Using a hanging drop technique, mouse ESCs (mESCs) were differentiated into cardiomyocytes. We then used the Aligent miRNAs chip (miRbase V16.0) to evaluate miRNA expression levels between the ESC-derived beating area enriched with cardiomyocytes and non-beating area. The expression levels of 19 miRNAs changed over 5-fold between two areas (n = 3, P < 0.05). Among them, 5 miRNAs were upregulated and 14 miRNAs were downregulated in the beating area compared with the non-beating area (P < 0.05). Then quantitative real-time-PCR was used to analyze the miRNAs with the differentiated expression level over 10-fold seen in the Aligent miRNAs chip. miR-196a, miR-196b and miR-467e were confirmed to be significantly lower in the beating area than those in the non-beating area (n = 3, P < 0.05). TargetScan analysis further suggested that miR-196a and miR-196b might be negatively related to the cardiomyocytes differentiation. Our findings provide a new clue for exploring roles of miRNAs in cardiac lineage commitment of mESCs.

Expression profiles of histone lysine demethylases during cardiomyocyte differentiation of mouse embryonic stem cells.

AIM: Histone lysine demethylases (KDMs) control the lineage commitments of stem cells. However, the KDMs involved in the determination of the cardiomyogenic lineage are not fully defined. The aim of this study was to investigate the expression profiles of KDMs during the cardiac differentiation of mouse embryonic stem cells (mESCs). METHODS: An in vitro cardiac differentiation system of mESCs with Brachyury (a mesodermal specific marker) and Flk-1(+)/Cxcr4(+) (dual cell surface biomarkers) selection was used. The expression profiles of KDMs during differentiation were analyzed using Q-PCR. To understand the contributions of KDMs to cardiomyogenesis, the mESCs on differentiation d 3.5 were sorted by FACS into Brachyury(+) cells and Brachyury(-) cells, and mESCs on d 5.5 were sorted into Flk-1(+)/Cxcr4(+) and Flk-1(-)/Cxcr4(-) cells. RESULTS: mESCs were differentiated into spontaneously beating cardiomyocytes that were visible in embryoid bodies (EBs) on d 7. On d 12-14, all EBs developed spontaneously beating cardiomyocytes. Among the 16 KDMs examined, the expression levels of Phf8, Jarid1a, Jhdm1d, Utx, and Jmjd3 were increased by nearly 2-6-fold on d 14 compared with those on d 0. Brachyury(+) cells showed higher expression levels of Jmjd3, Jmjd2a and Jhdm1d than Brachyury(-) cells. A higher level of Jmjd3 was detected in Flk-1(+)/Cxcr4(+) cells, whereas the level of Jmjd2c was lower in both Brachyury(+) cells and Flk-1(+)/Cxcr4(+) cells. CONCLUSION: KDMs may play important roles during cardiomyogenesis of mESCs. Our results provide a clue for further exploring the roles of KDMs in the cardiac lineage commitment of mESCs and the potential interference of cardiomyogenesis.

[Role of Rho/ROCK in the migration of vascular smooth muscle cells].

The migration of vascular smooth muscle cells (VSMCs) from media to intima is a critical step in the formation of atheroma and vascular stenosis as well as in the restenosis after vascular intervention. As an important downstream effector of RhoA, Rho-associated kinase (ROCK) plays an important role in VSMC migration and vascular remodeling by regulating actin filament cytoskeleton and focal adhesion. There are many bioactive substances such as aldosterone, sphingosine 1 phosphate (S1P), platelet-derived growth factor (PDGF) and angiotensin II (Ang II) that could induce VSMC migration through Rho/ROCK pathway by binding to their specific receptors. Studies on Rho/ROCK pathway could help us to better understand how cardiovascular diseases such as atherosclerosis and hypertension develop.

[Inhibitory effect of ginseng saponin IH901 on proliferation and metastasis of ECV304 cell line and its molecular mechanism].

This study aims to investigate the inhibitory effect on proliferation and metastasis of 20-O-(beta-D-glucopyranosyl)-20(S)-protopanaxadiol (IH901) on ECV304 cell line. MTT assay was used to examine the effect of cell proliferation inhibition and the adhesive ability of ECV304 cells to artificial basement membrane. Morphology of cell apoptosis was observed with phase contrast microscope. Apoptosis rate and cell cycle were detected by flow cytometry (FCM). Cell migration was measured by wound healing assay. ELISA kit was used to detect VEGF and bFGF. Caspases were detected by Western blotting. Results indicated that ginseng saponin IH901 can downregulate the expression of growth promoting protein VEGF and bFGF, and upregulate pro apoptosis protein cleaved caspase-9 and cleaved caspase-3. The increase in the apoptotic sub-G1 fraction is in a dose-dependent manner, and cell cycle arrests in the G0/G1 phase was detected by FCM. Morphological examination of IH901-treated samples showed cells with chromatin condensation, cell shrinkage, and all typical characteristics of apoptotic cells. Therefore, IH901 dramatically suppresses cell proliferation and adhesion and migration of ECV304 cell line.

Anti-proliferation and apoptosis induced by a novel intestinal metabolite of ginseng saponin in human hepatocellular carcinoma cells.

20-O-(beta-D-glucopyranosyl)-20(S)-protopanaxadiol (IH-901), a novel intestinal bacterial metabolite of ginseng protopanaxadiol saponins, is reported to induce apoptosis in a variety of cancer cells. We purified the compound and measured its in vitro anti-tumor activity. IH-901 inhibited cell growth of human hepatocellular carcinoma SMMC7721 cells in a dose- and time-dependent manner. We also found that IH-901 induced apoptotic cell death concurrent with cell cycle arrest in G0-G1 phase in SMMC7721 cells. At the molecular level, we show that IH-901 upregulates cytochrome c, p53, and Bax expression, and downregulates pro-caspase-3 and pro-caspase-9 expressions in a dose-dependent manner, while the levels of Bcl-2 and Bcl-X(L) were unchanged in IH-901-treated SMMC7721 cells. These results provide significant insight into the anticarcinogenic action of IH-901.