整合素及其在昆虫学中的研究进展

整合素是一类存在于细胞表面的重要黏附分子,通过其双向信号转导途径,介导细胞-细胞外基质与细胞-细胞间的黏附,在哺乳动物的许多生理、病理过程中起重要作用。昆虫整合素的研究主要集中在其对果蝇的生长发育及鳞翅目等昆虫先天性免疫反应的影响。     

αV,β3整合素在绵羊体外受精胚胎的表达模式研究

[目的]探讨胚胎附植调控因子αV,β3整合素在绵羊早期体外胚胎的表达情况,为早期胚胎发育及附植调控机理提供理论依据.[方法]采用RT-PCR和间接免疫荧光染色技术,检测绵羊体外受精个发育阶段胚胎中αV及β3整合素mRNA的表达模式及蛋白表达定位情况.[结果]在绵羊2-细胞至桑椹胚体外胚胎中未能检测到整合素αV及β3 mRNA的表达,但可以检测到囊胚期胚胎有微量整合素αV及β3 mRNA的表达.并且在绵羊第7d扩张囊胚和第8d孵化囊胚上均可检测到整合素αVβ3蛋白的表达,且蛋白表达主要分布在胚胎滋养层细胞周围,孵化囊胚蛋白表达量略高于扩张囊胚.[结论]αV,β3整合素在绵羊早期胚胎发育及附植过程中具有重要调控作用.     

家蚕整合素基因Bmintegrin αPS3的鉴定及亚细胞定位

【目的】克隆家蚕整合素基因Bmintegrin αPS3,分析其mRNA表达及亚细胞定位特征,并进行原核表达及蛋白纯化,为进一步探究Bmintegrin αPS3在家蚕中的功能奠定基础。【方法】利用RACE方法克隆获得Bmintegrin αPS3的cDNA全长序列;采用RT-PCR方法检测Bmintegrin αPS3的时空表达;在原核表达系统中表达获得Bmintegrin αPS3重组蛋白;并构建Bmintegrin αPS3真核表达载体,转染家蚕胚胎细胞系分析其蛋白亚细胞定位。【结果】家蚕整合素基因Bmintegrin αPS3 编码框全长为2 895 bp,编码965个氨基酸,含有整合素家族蛋白典型的integrin alpha结构域,预测其为跨膜蛋白。构建了Bmintegrin αPS3的原核表达系统,并利用亲和层析纯化获得高纯度的Bmintegrin αPS3原核表达蛋白,为进一步制备抗体获得足够的抗原。在家蚕细胞系中外源表达Bmintegrin αPS3蛋白,显示其主要定位于细胞质和细胞膜中。另外,RT-PCR结果显示Bmintegrin αPS3 mRNA 在血细胞中为特异持续表达。【结论】获得了Bmintegrin αPS3的完整cDNA序列及表达特征,经原核表达、纯化获得其融合蛋白,在细胞水平上初步分析了其亚细胞定位情况。     

整合素αvβ1在猪流行性腹泻病毒(PEDV)侵染Vero细胞过程中的作用

为明确整合素αvβ1在猪流行性腹泻病毒(PEDV)侵染过程中的作用,通过对整合素 αvβ1在Vero细胞表面的过表达和抑制反应,检测PEDV在侵染过程中的病毒载量和蛋白质表达量的变化.结果显示,Vero细胞表面整合素αvβ1的过表达使病毒载量和蛋白质表达量升高,Vero细胞表面整合素αvβ1基因的沉默使病毒载量和蛋白质...     

整合素与子宫内膜异位症相关性的研究现状

整合素是一类具有粘附和信号传递功能的细胞粘附分子受体。整合素中某些亚型的表达缺陷可能与子宫内膜异位症(endometriosis,EMS)患者的不孕密切相关。该文就整合素与EMS相关性研究进行综述。     

FMDV细胞表面受体研究概述

FMDV通过不同途径进入细胞,这个过程从病毒附着在细胞表面的受体开始。FMDV进入细胞的主要途径是通过网格蛋白介导的内吞途径结合整合素;在酸化的内吞囊泡内囊泡中病毒衣壳迅速分解,使产生的病毒RNA基因组释放。FMDV还可以使用硫酸乙酰肝素进入细胞。病毒通过细胞膜穴样内陷介导的内吞途径进入细胞。一旦病毒进入胞内体,胞内体中的低pH值将引起病毒基因组的脱衣壳,随后穿过胞内体膜进入细胞质。已经有许多整合素被确认为是FMDV的受体。本文将主要综述近年来FMDV受体的研究进展,并阐明这些受体在感染中的作用。     

中和血小板源性生长因子对A549人肺癌细胞生长及迁移的影响

目的 探讨中和血小板源性生长因子(platelet-derived growth factors,PDGFs)对A549人肺癌细胞生长和迁移的影响.方法 PDGF中和性抗体作用A549细胞后,MTT法及乳酸脱氢酶释放试验检测细胞增殖;丹单酰磺尸胺及吖啶橙染色检测细胞自噬;DAPI染色及caspase 3活性试验检测细胞凋亡;划痕试验及Transwell试验分析细胞迁移;免疫印迹及酶联免疫吸附试验检测整合素αv和基质金属蛋白酶9的表达.结果 PDGFs抗体明显抑制A549细胞体外增殖,诱导细胞发生自噬和凋亡,但同时增强肿瘤细胞迁移能力及整合素αv和MMP9的表达水平,整合素抑制剂西仑吉肽可部分逆转该现象.结论 中和PDGFs可抑制A549肿瘤细胞体外生长但促进其迁移.     

选择素及其配体在哺乳动物胚胎着床过程中的作用

选择素是一种非免疫来源的多价糖类结合蛋白,为细胞粘附分子(celladhesionmolecules,cAMs)超家族的一员,选择素家族有3个结构类似的成员:E-选择素、L-选择素、P-选择素,它们在炎症发生时可介导白细胞与血管内皮细胞之间、白细胞与白细胞及白细胞与血小板之间的粘附。近年来研究发现,选择素及其配体还在精卵识别、滋养层细胞和子宫内膜的相互识别、滋养层细胞侵入、胎盘形成等过程中发挥重要作用。在此,主要对E-选择素、L-选择素及它们的配体在哺乳动物胚胎着床过程中发挥的作用及其表达调节作一综述。     

表皮干细胞标记物在仿刺参正常和再生体壁中的表达研究

为探究仿刺参表皮再生的机制和再生修复过程中的表皮细胞来源,采用免疫荧光方法,观察β1整合素,α6整合素,角蛋白19 (ck19) 3种表皮干细胞标记物在仿刺参正常及创伤后再生不同时间段的体壁中的表达情况。结果表明ck19在对照组和试验组仿刺参体壁中均呈阳性,并且随着再生的进行,阳性细胞数量和分布区域均有变化。创伤第1天阳性细胞向创伤面上缘迁移,细胞数量同对照组;第3天阳性细胞数量显著下降;第5天阳性细胞数量最多;第7天阳性细胞数量有所下降;11天、13天阳性细胞的数量较第7天稍有增加;第19天阳性细胞数量同对照组,但排列很分散。β1整合素和α6整合素在正常及创伤后再生的体壁中均未见阳性信号出现。结合石蜡切片观察结果进行比较分析认为被ck19标记的细胞是参与仿刺参体壁表皮再生的干细胞和短暂扩增细胞,仿刺参表皮再生的机制属于新建再生。     

慢性肾功能不全者的骨髓造血功能

慢性肾功能不全的主要并发症之一是慢性尿毒症对血液细胞组成成份的影响。其中以肾性贫血最为重要,因为这是影响康复的重要因素,次为白细胞的异常。Schnurr发现白细胞功能障碍与肾功能障碍的严重度相     

Generation of an LFA-1 antagonist by the transfer of the ICAM-1 immunoregulatory epitope to a small molecule

The protein-protein interaction between leukocyte functional antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) is critical to lymphocyte and immune system function. Here, we report on the transfer of the contiguous, nonlinear epitope of ICAM-1, responsible for its association with LFA-1, to a small-molecule framework. These LFA-1 antagonists bound LFA-1, blocked binding of ICAM-1, and inhibited a mixed lymphocyte reaction (MLR) with potency significantly greater than that of cyclosporine A. Furthermore, in comparison to an antibody to LFA-1, they exhibited significant anti-inflammatory effects in vivo. These results demonstrate the utility of small-molecule mimics of nonlinear protein epitopes and the protein epitopes themselves as leads in the identification of novel pharmaceutical agents.     

咯利普兰通过MAPK/ERK信号通路抑制中性粒细胞的黏附

【目的】研究磷酸二酯酶4(PDE4)特异性抑制剂咯利普兰抑制中性粒细胞黏附的有关分子机制,明确其抗炎的主要信号通路,为PDE4选择性中药抑制剂的药理研究提供参考。【方法】猪中性粒细胞的提取采用密度梯度离心法,中性粒细胞与猪内皮细胞的黏附采用虎红比色法,中性粒细胞黏附分LFA-1和Mac-1表达量的检测采用流式细胞技术,中性粒细胞p38MAPK、ERK等磷酸化活性检测采用western blot法。【结果】咯利普兰可显著抑制fMLP刺激的中性粒细胞和内皮细胞的黏附(P0.05),极显著抑制fMLP刺激的中性粒细胞LFA-1和Mac-1的表达(P0.01),阻断fMLP刺激的中性粒细胞ERK磷酸化活性(P0.01),而对p38MAPK磷酸化活性无显著影响。【结论】咯利普兰可抑制中性粒细胞和内皮细胞黏附,其机制与阻断中性粒细胞ERK磷酸化进而抑制LFA-1和Mac-1表达有关。     

Involvement of a leukocyte adhesion receptor (LFA-1) in HIV-induced syncytium formation

Cell fusion (syncytium formation) is a major cytopathic effect of infection by human immunodeficiency virus (HIV) and may also represent an important mechanism of CD4+ T-cell depletion in individuals infected with HIV. Syncytium formation requires the interaction of CD4 on the surface of uninfected cells with HIV envelope glycoprotein gp120 expressed on HIV-infected cells. However, several observations suggest that molecules other than CD4 play a role in HIV-induced cell fusion. The leukocyte adhesion receptor LFA-1 is involved in a broad range of leukocyte interactions mediated by diverse receptor-ligand systems including CD4-class II major histocompatibility complex (MHC) molecules. Possible mimicry of class II MHC molecules by gp120 in its interaction with CD4 prompted an examination of the role of LFA-1 in HIV-induced cell fusion. A monoclonal antibody against LFA-1 completely inhibited HIV-induced syncytium formation. The antibody did not block binding of gp120 to CD4. This demonstrates that a molecule other than CD4 is also involved in cell fusion mediated by HIV.     

Luteolin prevents f MLP-induced neutrophils adhesion via suppression of LFA-1 and phosphodiesterase 4 activity

Luteolin is an active ingredient found early from Folium perillae and Flos lonicerae, and has a specific inhibition on phosphodiesterase 4(PDE4) activity in vitro. Researches show luteolin has pharmacological effects of anti-inflammation, anti-anaphylaxis, antitumor, antioxidant, protection of nervous system and so on, and has mainly been used for the treatment of respiratory inflammatory diseases, cancer and cardiovascular disease in clinic. PDE4, specific to hydrolyze cyclic AMP(c AMP), is considered to be a new anti-inflammatory target due to the decisive role on c AMP signal in inflammatory cells such as neutrophils. In order to explore the anti-inflammatory mechanism, we further studied the effects of luteolin on the activity and expression of PDE4, the expression of lymphocyte function-associated antigen-1(LFA-1) and macrophage-1(MAC-1) in neutrophils, and the adhesion of neutrophils and endothelial cells. The results showed that luteolin had a dose-dependent inhibition on both bare PDE4 activity and PDE4 in cultured neutrophils, and had an obviously promotive effect on gene expressions of PDE4 A, 4B and 4D in later period. Luteolin had a significant inhibitory effect on neutrophils adhesion and LFA-1 expression in early stage, and had no obvious effect on MAC-1 expression. Therefore, luteolin can inhibit LFA-1 expression of neutrophils, then inhibit the adhesion of neutrophils and endothelial cells, and the mechanism is at least related with the inhibition of PDE4 activity.     

Correction of CD18-deficient lymphocytes by retrovirus-mediated gene transfer

Leukocyte adhesion deficiency (LAD) is an inherited disorder of leukocyte function caused by derangements in CD18 expression. The genetic and functional abnormalities in a lymphocyte cell line from a patient with LAD have been corrected by retrovirus-mediated transduction of a functional CD18 gene. Lymphocytes from patients with LAD were exposed to CD18-expressing retrovirus and enriched for cells that express CD11a and CD18 (LFA-1) on the cell surface. Molecular and functional analyses of these cells revealed (i) one copy of proviral sequence per cell, (ii) viral-directed CD18 RNA that exceeded normal endogenous levels, (iii) normal quantities of CD11a and CD18 protein on the cell surface, and (iv) reconstitution of LFA-1-dependent adhesive function.     

Integrin-mediated long-term B cell retention in the splenic marginal zone

The mechanisms that control localization of marginal zone (MZ) B cells are poorly understood. Here we show that MZ B cells express elevated levels of the integrins LFA-1 (alphaLbeta2) and alpha4beta1 and that they bind to the ligands ICAM-1 and VCAM-1. These ligands are expressed within the MZ in a lymphotoxin-dependent manner. Combined inhibition of LFA-1 and alpha4beta1 causes a rapid and selective release of B cells from the MZ. Furthermore, lipopolysaccharide-triggered MZ B cell relocalization involves down-regulation of integrin-mediated adhesion. These studies identify key requirements for MZ B cell localization and establish a role for integrins in peripheral lymphoid tissue compartmentalization.     

天然LFA-3对于猪血清溶血作用和猪PBMC Et花环的影响

根据解离、吸收猪血清能够阻止正常猪血清对SRBC的破坏作用和猪PBMCE_1花环的形成,推断正常猪血清中存在天然的LFA—3,并从天然LFA—3与游离CD_2和膜CD_2的可能关系中提出了T淋巴细胞激活中游离CD_2调控途径的设想。     

小麦品种麦谷蛋白亚基的遗传变异分析

分析了９６个小麦品种高、低分子量麦谷蛋白亚基组成的及其分布规律,结果表明：强面筋品种与普通品种在高分子量及低分子量麦谷蛋白亚基组成上存在明显差异。强面筋品种含Ｇｌｕ－Ａｌａ（１亚基）、Ｇｌｕ－Ａ１ｂ（２＾＊亚基）、Ｇｌｕ－Ｂ１ｂ（７＋８亚基）、Ｇｌｕ－Ｂｌｉ（１７＋１８亚基）、Ｇｌｕ－Ｄｌｄ（５＋１０亚基）、Ｇｌｕ－Ａ３ｂ和Ｇｌｕ－Ｄ３ｃ的频率较高,而普通品种则含Ｇｌｕ－Ａｌｃ（Ｎ）、Ｇｌｕ－Ｂｌ     

Monitoring of blood vessels and tissues by a population of monocytes with patrolling behavior

The cellular immune response to tissue damage and infection requires the recruitment of blood leukocytes. This process is mediated through a classical multistep mechanism, which involves transient rolling on the endothelium and recognition of inflammation followed by extravasation. We have shown, by direct examination of blood monocyte functions in vivo, that a subset of monocytes patrols healthy tissues through long-range crawling on the resting endothelium. This patrolling behavior depended on the integrin LFA-1 and the chemokine receptor CX(3)CR1 and was required for rapid tissue invasion at the site of an infection by this "resident" monocyte population, which initiated an early immune response and differentiated into macrophages.