A multicolor flow cytometric assay for measurement of platelet-derived microparticles

Introduction

Flow cytometry (FCM) is the most commonly used method for detection of platelet-derived microparticles (PDMPs), but it is poorly standardized and mainly used for “bedside” analyses in fresh samples. If PDMPs could be analyzed in previously frozen samples it would increase the usefulness of the method. However, cell membrane fragments from contaminating cells created during freezing/thawing may cause artifacts and disturb measurements.

Materials and Methods

PDMPs were labeled with monoclonal antibodies directed against CD42a and CD62P, or CD42a and CD142. The PDMP gate was determined using forward scatter (FSC) and CD42a expression. The mean fluorescence intensities (MFIs) of CD62P or CD142 positive particles were translated into MESF -values (Molecules of Equivalent Soluble Fluorochrome) using a standard curve. FITC-labeled phalloidin (which binds to intracellular actin) was used to detect destroyed cells/cell fragments.

Results

Phalloidin-positive particles were significantly more common in supernatants of frozen/thawed platelet rich and platelet poor plasma samples compared with supernatants of platelet free plasma. High-speed centrifugation was then used to obtain PDMP samples with low contamination of cell fragments. Electron microscopy showed that these samples contained numerous round stained particles with cellular membranes of a size of 100-700 nm. Reproducibility experiments using plasma samples from healthy individuals showed that the coefficients of variation (CVs) of MESF values of CD62P and CD142 (both intra- and interassay) were < 10%, and the variation between two cytometers in two different laboratories was < 5%. We also found that PDMP expression of CD142 (i.e. tissue factor [TF]) and CD62P (i.e P-selectin) was around two times higher in samples from type 1-diabetes patients compared with those from healthy controls (p < 0.001).

Conclusions

The use of MESF values to quantify PDMP expression of P-selectin and TF yields reproducible data and enables comparison of data between laboratories. If high-speed centrifugation is performed, contamination of cell fragments is low in frozen/thawed samples.     

Substance P represents a novel first-line defense mechanism in the nose

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大鼠脑水肿模型中大分子物质的清除途径

目的：研究脑水肿模型中大分子物质由脑实质的清除途径。方法：将10ul藻红蛋白溶液注射到大鼠右侧尾壳核造成高蛋白性脑水肿,分别于注射后0．5、1、2、5、24h处死动物,取脑组织、双侧颈总动脉和颈部淋巴结,快速冰冻切片,荧光显微镜和共聚焦显微镜观察。结果：大鼠脑切片上,各时间点都可见荧光沿右侧胼胝体弥漫性分布,右侧脑室有微弱荧光信号。从注射后5h开始可见皮层灰质、尾壳核和蛛网膜下腔内的血管周围有荧光聚集,所有时间点的颈部淋巴结和颈总动脉都有荧光分布。共聚焦显微镜下,注射后24h注射侧大脑皮层和尾壳核内的毛细血管内皮细胞浆有强荧光信号,而胞核负染。结论：脑水肿时大分子物质在灰质和白质内的引流方式不同;毛细血管内皮细胞参与血管周围间隙内大分子物质的清除;颈部淋巴系统参与脑内大分子物质的引流。     

LncRNA AK085865 depletion ameliorates asthmatic airway inflammation by modulating macrophage polarization

Accumulating evidence indicates that regulators of macrophages polarization may play a key role in the development of allergic asthma (AA). However, the exact role of long non-coding RNAs (lncRNAs) in regulating in macrophages polarization in the pathogenesis of dermatophagoides farinae protein 1(Der f1)-induced AA is not fully understood. The purpose of this study was to determine the function of lncRNA AK085865 in regulating macrophages in AA. Here we report that lncRNA AK085865 served as a critical regulator of macrophages polarization and reduced the pathological progress of asthmatic airway inflammation. In response to the challenge of Der f1, AK085865^−/− mice displayed attenuated allergic airway inflammation, including decreased eosinophil in BALF and reduced production of IgE, which were associated with decreased mucous glands and goblet cell hyperplasia. In addition, Der f1-treated AK085865^−/− mice show fewer M2 macrophages when compared with WT asthmatic mice. After adopting bone marrow-derived macrophages (BMDM, M0) from WT mice, Der f1-treated AK085865^−/− mice also revealed a light inflammatory reactions. We further observed that the percentage of type II innate immune lymphoid cells (ILC2s) decreased in AK085865^−/− asthmatic mice. Moreover, M2 macrophages helped promote the differentiation of ILC2s, probably through the exosomal pathway secreted by M2 macrophages. Taken together, these findings reveal that AK085865 depletion can ameliorate asthmatic airway inflammation by modulating macrophage polarization and M2 macrophages can promote the differentiation of innate lymphoid cells progenitor (ILCP) into ILC2s.     

Activated plasmacytoid dendritic cells regulate type 2 innate lymphoid cell–mediated airway hyperreactivity

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Three-colour flow cytometric method to measure antibody-dependent tumour cell killing by cytotoxicity and phagocytosis

We have developed a three-colour flow cytometric method to assay the contributions of cytotoxicity and phagocytosis to antibody-dependent cell-mediated tumour cell killing. In this assay, tumour target cells are pre-labelled with CFSE, and mixed with effector cells and a tumour antigen-specific monoclonal antibody. After incubation of the cells with the antibody, effector cells are labelled with PE and dead cells with PI. Using flow cytometry, dead and phagocytosed tumour cells can be quickly and easily counted and the numbers summed to determine the total number of killed cells. One can thereby measure the phagocytic aspect of antibody-dependent cell-mediated tumour cell killing, otherwise only revealed by microscopic examination. The failure to detect phagocytosed, in addition to live and dead target cells, by standard assays may result in an underestimation of tumour cell killing and hence the potential of an antibody for immunotherapy of cancer. We illustrate the new method by analysing human monocyte-mediated cytotoxic and phagocytic cell killing of IGROV1 ovarian tumour cells by the ovarian tumour antigen-specific anti-folate binding protein monoclonal antibody, MOv18 IgE.     

The IL-33/ST2 axis is crucial in type 2 airway responses induced by Staphylococcus aureus–derived serine protease–like protein D

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Recombinant human ulinastatin improves immune dysfunction of dendritic cells in septic mice by inhibiting endoplasmic reticulum stress-related apoptosis

Urinary trypsin inhibitor (UTI), also known as ulinastatin, has been reported to protect multiple organs against inflammation- and/or injury-induced dysfunction. In the present study, we aimed to investigate the immunomodulation effects of a recombinant human ulinastatin (urinary trypsin inhibitor, UTI) (rhUTI) on splenic dendritic cells (DCs) in cecal ligation and puncture (CLP)-induced septic mice. CLP mice were treated with rhUTI intramuscularly at 0, 12, and 24 h after procedure. Splenic CD11c⁺ DCs were isolated and accessed with flow cytometry for apoptotic or phenotypic analysis. Protein markers and cytokines were determined with Western blotting or ELISA. Treatment with rhUTI could markedly upregulate levels of costimulatory molecules (CD80, CD86) and MHC-II on surface of the splenic DC in CLP mice. The apoptotic rate of splenic DCs was decreased in CLP mice after rhUTI treatment. The survival rate of septic mice was increased after treatment with rhUTI. In addition, protein level of markers in endoplasmic reticulum stress (ERS)-related apoptotic pathways (including GRP78, caspase-12, and CHOP) were obviously down-regulated in the rhUTI-treated group when compared with the CLP group. These results indicate that rhUTI protects CLP-induced sepsis in mice by improving immune response of splenic DCs and inhibiting the excessive ERS-mediated apoptosis.