Spironolactone inhibits apoptosis in rat mesangial cells under hyperglycaemic conditions via the Wnt signalling pathway

Mesangial cells (MCs) play a crucial role in maintaining structure and function of glomerular tufts, providing structural support for capillary loops and modulating glomerular filtration by their contractility. MCs apoptosis occurs in experimental diabetic nephropathy, and this correlates with worsening albuminuria. Accumulating evidence suggests that mineralocorticoid receptor (MR) blockade effectively reduces proteinuria in diabetic nephropathy; however, it is rarely known whether spironolactone (SPI), a nonspecific MR antagonist, inhibits apoptosis in MCs under hyperglycaemic conditions. The objectives of this study are to determine the relationship between SPI and apoptosis, and investigate the cell signalling pathway by which SPI inhibits apoptosis. Rat MCs were treated with 30 mM d-glucose and 10^?8, 10^?7 or 10^?6 M aldosterone (ALD) for 24 h. In some experiments, MCs were pretreated with 10^?7 M SPI or 10 mM LiCl for 1 h. Apoptosis was evaluated by cell nucleus staining and flow cytometric analyses, and caspase-3 activity was assayed. Gene and protein expression were quantified using quantitative real-time PCR and Western blotting, respectively. SPI directly inhibited high glucose and ALD-induced MCs apoptosis in a caspase-dependent manner. Importantly, SPI inhibited MCs apoptosis via the Wnt signalling pathway. SPI promoted activation of the Wnt signalling pathway in MCs, leading to upregulation of Wnt4 and Wnt5a mRNA expression, decreased GSK-3β protein expression and increased β-catenin protein expression. As a conclusion, this study suggests that SPI may inhibit apoptosis in MCs during hyperglycaemic conditions via the Wnt signalling pathway. Blockade of the ALD system may represent a novel therapeutic strategy to prevent MCs injury under hyperglycaemic conditions.     

Parabacteroides distasonis Alleviates Obesity and Metabolic Dysfunctions via Production of Succinate and Secondary Bile Acids

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肺纤维化分子治疗靶点的研究进展

肺纤维化(pulmonary fibrosis, PF)是临床常见的一种慢性进行性呼吸系统疾病,以中晚期出现肺组织的纤维化为病变特征。由于肺纤维化病因复杂,其发病机制至今仍不明确,这也成为该疾病治疗的最大难点,并且由于该病的高死亡率,寻求有效的治疗方法迫在眉睫。随着现代分子生物学技术的广泛应用以及对该疾病的发生机制和病理生理变化研究的不断深入,发现AMPK、mTOR和JNK等相关信号通路以及ECM沉积和氧化应激等在肺纤维化发病机制中起着重要作用。因此,针对这些通路中的相关分子的靶点治疗将成为肺纤维化治疗的新趋势。本文旨在对肺纤维化治疗相关的细胞因子以及micro RNA分子靶点研究进展做一总结,为防治肺纤维化提供新的理论依据,同时为临床诊疗提供参考。     

Combined mutagenesis of <Emphasis Type="Italic">Rhodosporidium toruloides</Emphasis> for improved production of carotenoids and lipids

Objectives

To improve production of lipids and carotenoids by the oleaginous yeast Rhodosporidium toruloides by screening mutant strains.

Results

Upon physical mutagenesis of the haploid strain R. toruloides np11 with an atmospheric and room temperature plasma method followed by chemical mutagenesis with nitrosoguanidine, a mutant strain, R. toruloides XR-2, formed dark-red colonies on a screening plate. When cultivated in nitrogen-limited media, XR-2 cells grew slower but accumulated 0.23 g lipids/g cell dry wt and 0.75 mg carotenoids/g CDW. To improve its production capacity, different amino acids and vitamins were supplemented. p-Aminobenzoic acid and tryptophan had beneficial effects on cell growth. When cultivated in nitrogen-limited media in the presence of selected vitamins, XR-2 accumulated 0.41 g lipids/g CDW and 0.69 mg carotenoids/g CDW.

Conclusions

A mutant R. toruloides strain with improved production profiles for lipids and carotenoids was obtained, indicating its potential to use combined mutagenesis for a more productive phenotype.

     

基于共生理论的兵团与地方城市“三生”功能跨界整合发展研究

基于共生理论,选取乌鲁木齐市、五家渠市、昌吉市为研究案例区,构建"三生"空间评价指标体系及"三生"功能评价指标体系,探讨乌五昌地区"三生"空间时空分异格局,借助共生度模型,识别兵团城市与地方城市"三生"功能共生发展模式,并对兵地城市跨界融合发展提供理论建议。结果表明：（1）研究区生产和生活空间面积呈上升趋势,生态空间面积呈下降趋势。（2）在生产功能方面,五家渠市与乌鲁木齐市、昌吉市共生模式分别为正向非对称共生、反向非对称共生,生活功能与生态功能方面,均为正向非对称共生,各功能城市间影响程度不同。（3）基于"三生"空间格局及"三生"功能共生模式,提出兵地融合发展建议,生产方面建立四区,三轴,一基地,生活方面加强交通路网建设,生态方面兵地协同建立生态保护区。     

酵母金属硫蛋白对酵母和小鼠抗γ射线损伤的作用

酿酒酵母BD101菌株的金属硫蛋白能清除羟基自由基。含金属硫蛋白的酵母菌有拮抗60Coγ射线的作用。用计数血液中血小板（PLT）、白细胞（WBC）变化来研究酵母Cu－MT在小鼠γ射线损伤中的作用。结果表明,该菌Cu－MT对PLT降低的改善和回升有作用。但未观察到其对WBC总数变化的影响。提示酿酒酵母Cu－MT在临床放射病治疗和放疗后抗出血方面有良好的应用前景。     

A previously uncharacterized two-component signaling system in uropathogenic Escherichia coli coordinates protection against host-derived oxidative stress with activation of hemolysin-mediated host cell pyroptosis

Uropathogenic Escherichia coli (UPEC) deploy an array of virulence factors to successfully establish urinary tract infections. Hemolysin is a pore-forming toxin, and its expression correlates with the severity of UPEC infection. Two-component signaling systems (TCSs) are a major mechanism by which bacteria sense environmental cues and respond by initiating adaptive responses. Here, we began this study by characterizing a novel TCS (C3564/C3565, herein renamed orhK/orhR for oxidative resistance and hemolysis kinase/regulator) that is encoded on a UPEC pathogenicity island, using bioinformatic and biochemical approaches. A prevalence analysis indicates that orhK/orhR is highly associated with the UPEC pathotype, and it rarely occurs in other E. coli pathotypes tested. We then demonstrated that OrhK/OrhR directly activates the expression of a putative methionine sulfoxide reductase system (C3566/C3567) and hemolysin (HlyA) in response to host-derived hydrogen peroxide (H₂O₂) exposure. OrhK/OrhR increases UPEC resistance to H₂O₂ in vitro and survival in macrophages in cell culture via C3566/C3567. Additionally, OrhK/OrhR mediates hemolysin-induced renal epithelial cell and macrophage death via a pyroptosis pathway. Reducing intracellular H₂O₂ production by a chemical inhibitor impaired OrhK/OrhR-mediated activation of c3566-c3567 and hlyA. We also uncovered that UPEC links the two key virulence traits by cotranscribing the c3566-c3567 and hlyCABD operons. Taken together, our data suggest a paradigm in which a signal transduction system coordinates both bacterial pathogen defensive and offensive traits in the presence of host-derived signals; and this exquisite mechanism likely contributes to hemolysin-induced severe pathological outcomes.     

An improved particle bombardment for the generation of transgenic plants by direct immobilization of relleasable Tn5 transposases onto gold particles

We have developed a modified particle bombardment method for plant transgenesis. An intein-tag and a 6×Cys-tag were successively fused to the N-terminus of a hyperactive Tn5 transposase. The modified transposase was immobilized on bare gold microscopic particles via covalent binding of a 6×Cys-tag sulfydryl groups to the gold surface. The tethered transposase can bind the transposon DNA in vitro to form the transposome in the absence of Mg2? ions. After bombardment of the gold particles carrying the transposomes into the plant cells, the transposomes will be released from the carrier due to the activated self-cleavage function of intein-tag. Our data showed this procedure integrated foreign DNA into the plant genome with an increased transformation frequency as compared to the conventional particle bombardment method. A single copy insertion can also be obtained by decreasing of the assembled transposon DNA amount in relation to plant cell biomass.     

Use of Ssp dnaB derived mini-intein as a fusion partner for production of recombinant human brain natriuretic peptide in Escherichia coli

To prevent in vivo degradation, small peptides are usually expressed in fusion proteins from which target peptides can be released by proteolytic or chemical reagents. In this report, a modified Ssp dnaB mini-intein linked with a chitin binding domain tag was used as a fusion partner for production of human brain natriuretic peptide (hBNP), a hormone for the treatment of congestive heart failure. The fusion protein was expressed as an inclusion body in Escherichia coli. After refolding, the fusion protein was purified with a chitin affinity column, and dnaB mini-intein mediated peptide-bond hydrolysis was triggered by shifting the pH in the chitin column to 7.0 at 25 degrees C for 16 h, which led to the release and separation of hBNP from its fusion partner. The hBNP sample was further purified with reverse phase HPLC and its biological activity was assayed in vitro. It was found that hBNP had a potent vasodilatory effect on rabbit aortic strips with an EC(50) of (1.24+/-0.32)x10(-6)mg/ml, which was similar to that of the synthetic BNP standard. The expression strategy described here promises to produce small peptides without use of proteolytic or chemical reagents.