Effects of serum reduction and VEGF supplementation on angiogenic potential of human adipose stromal cells in vitro

Objectives

This study investigated effects of reduced serum condition and vascular endothelial growth factor (VEGF) on angiogenic potential of adipose stromal cells (ASCs) in vitro.

Materials and methods

Adipose stromal cells were cultured in three different types of medium: (i) F12/DMEM (FD) supplemented with 10% FBS from passage 0 (P0) to P6; (ii) FD supplemented with 2% FBS at P6; and (iii) FD supplemented with 2% FBS plus 50 ng/ml of VEGF at P6. Morphological changes and growth rate of ASCs were recorded. Changes in stemness, angiogenic and endogenic genes’ expressions were analysed using Real‐Time PCR.

Results

Adipose stromal cells changed from fibroblast‐like shape when cultured in 10% FBS medium to polygonal when cultured in 2% FBS plus VEGF‐supplemented medium. Their growth rate was lower in 2% FBS medium, but increased with addition of VEGF. Real‐Time PCR showed that ASCs maintained most of their stemness and angiogenic genes’ expression in 10% FBS at P1, P5 and P6, but this increased significantly in 2% FBS at P6. Endogenic genes expression such as PECAM‐1, VE chaderin and VEGFR‐2 decreased after serial passage in 10% FBS, but increased significantly at P6 in 2% FBS. Addition of VEGF did not cause any significant change in gene expression level.

Conclusion

Adipose stromal cells had greater angiogenic potential when cultured in reduced serum conditions. VEGF did not enhance their angiogenic potential in 2% FBS‐supplemented medium.

     

稳定碳同位素在滨海湿地碳生物地球化学循环中的应用

碳作为滨海湿地中重要的生命元素,其生物地球化学循环过程是滨海湿地研究的核心内容之一.稳定同位素技术越来越多地被应用到滨海湿地碳生物地球化学循环过程的研究中,提高了其研究水平,并推动了其研究的进程.本文从有机物质生产、土壤有机质来源、食物链传递、温室气体排放以及可溶性有机碳输出5个方面,综述了滨海湿地碳生物地球化学循环过程的稳定同位素研究进展.通过植物及土壤δ13C值的测定进行有机质的生产机理研究及外源追溯,通过对比各生物种群的δ13C值分析碳在生态系统中的流动过程,通过湿地排放温室气体及可溶性有机碳δ13C值的测定揭示影响碳输出的环境因子.最后,文章总结了当前研究中存在的问题,并对其研究前景进行了展望.     

XBP-1u suppresses autophagy by promoting the degradation of FoxO1 in cancer cells

Autophagy is activated to maintain cellular energy homeostasis in response to nutrient starvation. However, autophagy is not persistently activated, which is poorly understood at a mechanistic level. Here, we report that turnover of FoxO1 is involved in the dynamic autophagic process caused by glutamine starvation. X-box-binding protein-1u (XBP-1u) has a critical role in FoxO1 degradation by recruiting FoxO1 to the 20S proteasome. In addition, the phosphorylation of XBP-1u by extracellular regulated protein kinases1/2 (ERK1/2) on Ser61 and Ser176 was found to be critical for the increased interaction between XBP-1u and FoxO1 upon glutamine starvation. Furthermore, knockdown of XBP-1u caused the sustained level of FoxO1 and the persistent activation of autophagy, leading to a significant decrease in cell viability. Finally, the inverse correlation between XBP-1u and FoxO1 expression agrees well with the expression profiles observed in many human cancer tissues. Thus, our findings link the dynamic process of autophagy to XBP-1u-induced FoxO1 degradation.     

QTL Mapping of Downy Mildew Resistance in an Introgression Line Derived from Interspecific Hybridization Between Cucumber and Cucumis hystrix

Downy mildew (DM), caused by Pseudoperonospora cubensis (Berk. & M.A. Curtis) Rostovzev, is a worldwide major disease of cucumbers (Cucumis sativus L.). By screening 10 introgression lines (ILs) derived from interspecific hybridization between cucumber and the wild Cucumis, C. hystrix, through a whole plant assay, one introgression line (IL52) was identified with high DM‐resistance. IL52 was further used as a resistant parent to make an F₂ population with ‘changchunmici’ (susceptible parent). The F₂ population (300 plants) was investigated for DM‐yellowing, DM‐necrosis and DM‐resistance in the adult stage. A genetic map spanning 642.5 cM with 104 markers was constructed and used for QTL analysis from the population. Three QTL regions were identified on chromosome 5 and chromosome 6. By interval mapping analysis, two QTLs for DM‐resistance were determined on chromosome 5 (DM_5.1 and DM_5.2), which explained 17.9% and 14.2% of the variation, respectively. QTLs for DM‐yellowing were in the same regions as DM‐resistance. For DM‐necrosis, by interval mapping analysis, one QTL was determined on chromosome 5 (Necr_5.1) that explained 18.3% of the variation and one on chromosome 6 (Necr_6.1) that explained 13.9% of the variation. Our results indicated that the identification of molecular markers linked to the QTLs could be further applied for marker‐assisted selection (MAS) of downy mildew resistance in cucumber.     

Nature of the slow relaxation of smooth muscle induced by a EP2 receptor agonist with a non-prostanoid structure

The remarkably slow onset/offset of relaxation of guinea-pig isolated trachea induced by a ‘non-prostanoid’ EP₂ receptor agonist, (o-(o-benzyloxy)-cinnamyl)-cinnamic acid (coded (L)-9), was investigated. (L)-9 kinetics was slightly faster on mouse trachea and considerably faster on rabbit vena cava. In each case, reversal of (L)-9 relaxation by the selective EP₂ antagonist ACA-23 was rapid and similar to other EP₂ agonists (e.g. ONO-AE1-259). On guinea-pig aorta, in the presence of extensive EP₂ receptor blockade, (L)-9 inhibited TP agonist-induced contraction more slowly than TP antagonists of similar affinity. The slower kinetics of (L)-9 appear to correlate with greater adventitial/submucosal barriers and thicker smooth muscle layers in the tissues examined. It is proposed that interactions of (L)-9 with EP₂ and TP receptors are not rate-limiting, rather diffusion to and from the centre of the muscle mass is retarded by the high lipophilicity of (L)-9 (logP=6.69; ONO-AE1-259=3.95).     

Light-controlled inhibition of malignant glioma by opsin gene transfer

Glioblastomas are aggressive cancers with low survival rates and poor prognosis because of their highly proliferative and invasive capacity. In the current study, we describe a new optogenetic strategy that selectively inhibits glioma cells through light-controlled membrane depolarization and cell death. Transfer of the engineered opsin ChETA (engineered Channelrhodopsin-2 variant) gene into primary human glioma cells or cell lines, but not normal astrocytes, unexpectedly decreased cell proliferation and increased mitochondria-dependent apoptosis, upon light stimulation. These optogenetic effects were mediated by membrane depolarization-induced reductions in cyclin expression and mitochondrial transmembrane potential. Importantly, the ChETA gene transfer and light illumination in mice significantly inhibited subcutaneous and intracranial glioma growth and increased the survival of the animals bearing the glioma. These results uncover an unexpected effect of opsin ion channels on glioma cells and offer the opportunity for the first time to treat glioma using a light-controllable optogenetic approach.     

Protein Phosphatase 2A Catalytic Subunit α Plays a MyD88-Dependent,Central Role in the Gene-Specific Regulation of Endotoxin Tolerance

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Highlights? PP2Ac is constitutively activated and targets MyD88 in LPS-tolerized macrophages ? Constitutively active PP2Ac shifts a proinflammatory MyD88 to its prosurvival mode ? Constitutively active PP2Ac reprograms gene-specific chromatin modification landscape ? Constitutively active PP2Ac broadly defines ET at both signaling and epigenetic levels     

Impact of Vitamin D on Chronic Kidney Diseases in Non-Dialysis Patients: A Meta-Analysis of Randomized Controlled Trials

Background and Objectives

Recent studies have supported a role for both newer and more established vitamin D compounds in improving proteinuria, although systematic evaluation is lacking. Furthermore, concerns remain regarding the influence of vitamin D on the progression of renal function. We analyzed the efficacy and safety of vitamin D in non-dialysis patients and compared the use of newer versus established vitamin D compounds by performing a meta-analysis of randomized controlled trials.

Design

A literature search of PubMed (1975 to September, 2012), EMBASE.com (1966 to September, 2012) and Ovid EBM Reviews (through September, 2012) was conducted.

Results

Eighteen studies were eligible for final inclusion; of these, six explored the effects of vitamin D on proteinuria, twelve studied the effects of supplementation on renal function, and fifteen discussed the incidence of hypercalcemia. Compared to the placebo or no interference, both the newer and established vitamin D sterols reduced proteinuria to a similar extent (RR, 2.00; 95% CI, 1.42 to 2.81). No decrease in the glomerular filter rate was observed (SMD, −0.10; 95%CI, −0.24 to 0.03), and the risk for dialysis initiation was 1.48 (95% CI, 0.54 to 4.03) with vitamin D treatment. Additionally, there was an increased risk of hypercalcemia for patients treated with either newer or established vitamin D compounds as compared with the controls (RR, 4.78; 95% CI, 2.20 to 10.37). The head-to-head studies showed no differences in the effects of either newer or established compounds on proteinuria or the risk of hypercalcemia. No serious adverse events were associated with the administration of vitamin D.

Conclusions

Vitamin D therapy appears to decrease proteinuria and have no negative influence on renal function in non-dialysis patients. But the occurrence of hypercalcemia should be evaluated when vitamin D is provided. No superiority for newer versus established vitamin D analogue is found.