Wistar大鼠幼年期丰富环境刺激对其社会竞争行为的影响

目的：探讨大鼠幼年期丰富环境经历对其成年后焦虑样行为和社会竞争行为的影响。方法：幼年期Wistar大鼠（生后21天）分为标准饲养组（对照组）和丰富环境刺激（EE）组。对照组为持续在标准实验室饲养条件下饲养;丰富环境组为生后21天至行为学检查时持续在丰富环境下饲养。在生后70天进行行为学检测：采用高架十字迷宫方法测试焦虑样行为;采用社会优势管道试验观察社会竞争性行为。结果：高架十字迷宫实验结果显示,与对照组相比,丰富环境组在开放臂的时间和次数显著增加;优势管道实验结果显示丰富环境刺激组大鼠的社会竞争力明显下降。结论：大鼠幼年期丰富环境刺激可改善大鼠的焦虑样情绪,但导致大鼠社会竞争力下降。     

液质连用分析重组胰高血糖素样肽-1受体激动剂肽图

目的：建立高效液相系统肽图分析法,用于重组胰高血糖素样肽-1受体激动剂（rExendin-4）的质量控制。方法：应用高效液相系统摸索最佳胰蛋白酶切和色谱条件,并采用液质联用系统分析肽段的精确相对分子量和氨基酸序列。结果：根据酶切条件摸索,确定酶切条件为：rExendin-4原液与胰蛋白酶按照质量比为100：1混匀,37℃酶切4小时,根据肽段的色谱保留时间、相对分子质量及对其碰撞诱导解离质谱的解析结果,归属出肽图中各肽段所在的色谱峰,与理论值完全一致。结论：本法精确度高、重复性好、自动化程度高,能够用于rExendin-4原液肽图分析。     

Toll‐like receptor 9 protects non‐immune cells from stress by modulating mitochondrial ATP synthesis through the inhibition of SERCA2

Toll‐like receptor 9 (TLR9) has a key role in the recognition of pathogen DNA in the context of infection and cellular DNA that is released from damaged cells. Pro‐inflammatory TLR9 signalling pathways in immune cells have been well investigated, but we have recently discovered an alternative pathway in which TLR9 temporarily reduces energy substrates to induce cellular protection from stress in cardiomyocytes and neurons. However, the mechanism by which TLR9 stimulation reduces energy substrates remained unknown. Here, we identify the calcium‐transporting ATPase, SERCA2 (also known as Atp2a2), as a key molecule for the alternative TLR9 signalling pathway. TLR9 stimulation reduces SERCA2 activity, modulating Ca²⁺ handling between the SR/ER and mitochondria, which leads to a decrease in mitochondrial ATP levels and the activation of cellular protective machinery. These findings reveal how distinct innate responses can be elicited in immune and non‐immune cells—including cardiomyocytes—using the same ligand‐receptor system.     

不同粘度对比剂对冠状动脉造影患者肾功能的影响

目的：对比剂肾病（CIN）是介入治疗中常见并发症之一。由于对比剂肾病发病机制复杂,其确切的机制尚不明确,有研究认为应用渗透压相似的对比剂,高粘度组对比剂引起CIN的几率明显高于低粘度组。本研究探讨接受不同粘度对比剂冠状动脉造影检查的患者术后引起肾功能损害的差异及其可能的机制。方法：80例接受冠状动脉造影检查的患者随机分为两组。分别为20℃碘海醇组、37℃碘海醇组,每组各40例。分别于冠脉造影前8h、冠脉造影后48h采集同一患者肘正中静脉血进行血清肌酐（Scr）、血清胱抑素C（CysC）检测,并对数据进行统计学分析。结果：两组患者组间比较基本资料无明显差异,两组患者术后Ser、CysC较术前均升高,差异均有统计学意义（P〈0．05）;20℃碘海醇组术后Scr较37℃碘海醇组升高不明显,差异无统计学意义（P〉0．05）;20℃碘海醇组术后CysC较37℃碘海醇组升高明显,差异有统计学意义（P〈0．05）。结论：冠脉造影检查时．对比剂对患者的肾功能有损害;选择低粘度对比剂可能减少其对冠状动脉造影患者的肾功能的不良影响;其作用机制可能与对比剂改变血液粘滞性,从而影响肾血流有关。     

The RNAi machinery controls distinct responses to environmental signals in the basal fungus Mucor circinelloides

Background

RNA interference (RNAi) is a conserved mechanism of genome defence that can also have a role in the regulation of endogenous functions through endogenous small RNAs (esRNAs). In fungi, knowledge of the functions regulated by esRNAs has been hampered by lack of clear phenotypes in most mutants affected in the RNAi machinery. Mutants of Mucor circinelloides affected in RNAi genes show defects in physiological and developmental processes, thus making Mucor an outstanding fungal model for studying endogenous functions regulated by RNAi. Some classes of Mucor esRNAs map to exons (ex-siRNAs) and regulate expression of the genes from which they derive. To have a broad picture of genes regulated by the silencing machinery during vegetative growth, we have sequenced and compared the mRNA profiles of mutants in the main RNAi genes by using RNA-seq. In addition, we have achieved a more complete phenotypic characterization of silencing mutants.

Results

Deletion of any main RNAi gene provoked a deep impact in mRNA accumulation at exponential and stationary growth. Genes showing increased mRNA levels, as expected for direct ex-siRNAs targets, but also genes with decreased expression were detected, suggesting that, most probably, the initial ex-siRNA targets regulate the expression of other genes, which can be up- or down-regulated. Expression of 50% of the genes was dependent on more than one RNAi gene in agreement with the existence of several classes of ex-siRNAs produced by different combinations of RNAi proteins. These combinations of proteins have also been involved in the regulation of different cellular processes. Besides genes regulated by the canonical RNAi pathway, this analysis identified processes, such as growth at low pH and sexual interaction that are regulated by a dicer-independent non-canonical RNAi pathway.

Conclusion

This work shows that the RNAi pathways play a relevant role in the regulation of a significant number of endogenous genes in M. circinelloides during exponential and stationary growth phases and opens up an important avenue for in-depth study of genes involved in the regulation of physiological and developmental processes in this fungal model.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1443-2) contains supplementary material, which is available to authorized users.     

C-type lectin-like molecule-1 (CLL1)-targeted TRAIL augments the tumoricidal activity of granulocytes and potentiates therapeutic antibody-dependent cell-mediated cytotoxicity

The therapeutic effect of anti-cancer monoclonal antibodies stems from their capacity to opsonize targeted cancer cells with subsequent phagocytic removal, induction of antibody-dependent cell-mediated cytotoxicity (ADCC) or induction of complement-mediated cytotoxicity (CDC). The major immune effector cells involved in these processes are natural killer (NK) cells and granulocytes. The latter and most prevalent blood cell population contributes to phagocytosis, but is not effective in inducing ADCC. Here, we report that targeted delivery of the tumoricidal protein tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) to granulocyte marker C-type lectin-like molecule-1 (CLL1), using fusion protein CLL1:TRAIL, equips granulocytes with high levels of TRAIL. Upon CLL1-selective binding of this fusion protein, granulocytes acquire additional TRAIL-mediated cytotoxic activity that, importantly, potentiates antibody-mediated cytotoxicity of clinically used therapeutic antibodies (e.g., rituximab, cetuximab). Thus, CLL1:TRAIL could be used as an adjuvant to optimize the clinical potential of anticancer antibody therapy by augmenting tumoricidal activity of granulocytes.     

Variations in the expression of pili: the effect on adherence of Neisseria meningitidis to human epithelial and endothelial cells

The effect of variations in Neisseria meningitidis pili on bacterial interactions with three epithelial cell lines as well as human umbilical vein endothelial cells was studied using a panel of seven strains expressing Class I or Class II pili. Comparison of adherence of piliated and pilus-deficient variants of each strain to epithelial cells suggested that Class I pili may mediate bacterial adherence with all three epithelial cell lines. In contrast, Class II pili of the strains used did not increase bacterial adherence to Hep-2 larynx carcinoma cells, although an increase in adherence to Chang conjunctival and A549 lung carcinoma epithelial cells was observed in the Class II pili-expressing strains. In addition to these interclass functional variations, differences in adherence to epithelial cells were also observed among Class I and Class II strains. Functionally different pilin variants of one Class I strain, MC58, were obtained by single colony isolation. One piliated variant was identified which had concurrently lost the ability to adhere to both Chang and Hep-2 cells ('non-adherent' phenotype; adherence of less than 2 bacteria per cell). In addition, several adherent pilin variants were isolated from non-adherent Pil- and Pil+ bacteria by selection on Chang cells (adherence of 10-25 bacteria per cell). In contrast to epithelial cells, all variant pili, whether of Class I or Class II, adhered to endothelial cells in substantially larger numbers (greater than 50 bacteria per cell) and therefore implied the existence of distinct mechanisms in pilus-facilitated interactions of N. meningitidis with endothelial and epithelial cells.     

High allelic diversity in the methyltransferase gene of a phase variable type III restriction-modification system has implications for the fitness of Haemophilus influenzae

Phase variable restriction-modification (R-M) systems are widespread in Eubacteria. Haemophilus influenzae encodes a phase variable homolog of Type III R-M systems. Sequence analysis of this system in 22 non-typeable H.influenzae isolates revealed a hypervariable region in the central portion of the mod gene whereas the res gene was conserved. Maximum likelihood (ML) analysis indicated that most sites outside this hypervariable region experienced strong negative selection but evidence of positive selection for a few sites in adjacent regions. A phylogenetic analysis of 61 Type III mod genes revealed clustering of these H.influenzae mod alleles with mod genes from pathogenic Neisseriae and, based on sequence analysis, horizontal transfer of the mod–res complex between these species. Neisserial mod alleles also contained a hypervariable region and all mod alleles exhibited variability in the repeat tract. We propose that this hypervariable region encodes the target recognition domain (TRD) of the Mod protein and that variability results in alterations to the recognition sequence of this R-M system. We argue that the high allelic diversity and phase variable nature of this R-M system have arisen due to selective pressures exerted by diversity in bacteriophage populations but also have implications for other fitness attributes of these bacterial species.     

妊娠对于父源性皮肤移植存活时间的影响

母胎耐受机制的阐明,将为器官移植免疫耐受方案的研究提供重要启示.本研究旨在阐明妊娠状态对父系来源移植皮片的存活是否有保护作用.2月龄雌性C57BL/6小鼠和2～4月龄BALB/c雄性小鼠同笼受孕.采用流式细胞技术确定妊娠过程中调节性T细胞（Treg）比例的时间变化规律.以单向混合淋巴细胞反应（MLR）手段比较研究妊娠对于父系来源脾细胞刺激后产生的增殖反应的影响.通过同种异体小鼠全厚皮片移植模型,观察妊娠对于父系来源移植皮片的存活是否具有保护作用.并用分子生物学技术研究此种效能的可能机制.结果显示,C57BL/6小鼠妊娠过程中,Treg占CD4＋T细胞的比例从妊娠前的4.2%逐渐上升,受孕8天左右达到高峰值（6.8%）,此后开始下降并逐渐回复至基线水平.MLR结果表明,针对父系来源脾细胞的刺激,妊娠组较对照组呈现显著的低反应性,其平均刺激指数分别是7.8和13.6（P〈0.05）.定量PCR研究表明,血红素加氧酶-1和吲哚胺2,3双加氧酶mRNA在胎盘高表达,在脾脏低表达（P〈0.05）.父系来源的移植皮片的平均存活时间在妊娠组和非妊娠组分别是7.67和7.08天,无统计学差异（P〉0.05）.由此认为,在小鼠妊娠过程中,尽管出现了具有免疫抑制功能的Treg的比例增加,尽管有针对父系来源刺激细胞的较低的MLR反应性,但是单次妊娠对于父系来源的移植皮片的存活,在本研究条件下,未能显示具有统计学意义的保护作用.