P-选择素糖蛋白配体1与白细胞的起始黏附

P-选择素糖蛋白配体1（P—selectin glycoprotein ligand 1,PSGL-1）是20世纪90年代初期发现的一种具同源二聚体结构的跨膜糖蛋白,表达于几乎所有白细胞表面,是迄今为止阐述得最为详尽的选择素配体。PSGL-1是以P-选择素为亲和探针分离得到的,与P-选择素有高度的亲和性。近年来,越来越多的研究证明了PSGL-1同时也是L-选择素和E-选择素的生理配体。通过PSGL-1与选择素分子间的相互作用,白细胞在血管内皮细胞上产生滚动（即起始黏附）,进而使白细胞逐步活化并稳定黏附于血管内皮。现从PSGL-1的结构、分布、表达调控、信号转导、生理病理角色、临床应用等方面进行综述。     

抗P-选择素凝集素-EGF功能域单抗对人树突状细胞成熟及功能抑制作用分析

在发现抗P-选择素凝集素-EGF功能域单抗(PsL-EGFmAb)对体外培养人树突状细胞(DC)成熟及功能有抑制作用基础上,进一步观察了PsL-EGFmAb对DC干预调节的作用机制。通过SCF、GM-CSF、TGF-β1、Flt-3L和TNF-α体外培养体系,从脐血CD34 造血干细胞中诱导扩增获得DC,并于成熟过程中用PsL-EGFmAb进行干预。采用流式细胞仪检测细胞表面分子表达;RT-PCR检测细胞内NF-κBp50、NF-κBp65mRNA表达;MTT比色法检测T细胞增殖反应,以及ELISA法测定IL-12p70分泌的含量。结果显示,PsL-EGFmAb对DC表面特异性C型凝集素DC-SIGN(CD209)表达有抑制作用,同时也能抑制DC细胞内NF-κBp50、NF-κBp65mRNA表达,相应抑制其黏附共刺激分子CD11c、CD83、CD80、CD86表达,以及IL-12p70分泌,此外也可抑制DC体外刺激T细胞增殖的能力。研究结果表明,PsL-EGFmAb对DC成熟及功能的抑制作用,提示与其抑制作为DC模式识别受体及功能分子DC-SIGN有关,并可能是通过影响NF-κB信号途径起作用。     

人DC体外分化成熟特性及抗P-选择素功能域单抗对其干预调节

结合树突状细胞(DC)生物学特性, 探讨抗P-选择素lectin-EGF功能域单抗(PsL-EGFmAb)对体外培养人DC成熟和功能干预调节的作用. 通过SCF, GM-CSF, TGF-β₁, Flt-3L及TNF-α体外培养体系, 从脐血CD34⁺造血干细胞中诱导扩增获得DC, 并于细胞成熟过程中用PsL-EGFmAb及辅以IL-10作为对照进行干预. 分别观察和检测DC形态学及细胞活力, 细胞表面分子HLA-DR, CD1a, CD11c, CD54, CD83, CD80, CD86, CD209(DC-SIGN)及CD62P, E, L(P-、E-、L-选择素)表达, 细胞内活性氧(ROS)水平, 及IL-12p35, p40 mRNA与NF-κBP50, P65 mRNA表达, 培养上清液中IL-12p70分泌含量, 以及DC体外对T淋巴细胞刺激能力, 以此分析PsL-EGFmAb 对DC成熟与功能的干预状况. 结果显示, 未成熟DC高表达属模式识别受体的C型凝集素DC-SIGN外, 且胞内蓄积适量ROS, 具备了细胞吞噬能力. 成熟DC除仍高表达DC-SIGN, 伴随细胞内NF-κB基因明显表达, 其表面黏附共刺激分子CD11c, CD83, CD80, CD86表达上调, 且细胞因子IL-12合成分泌增加, 并具明显的体外刺激T淋巴细胞增殖能力, 符合于抗原提呈细胞特征. 此外, 未成熟和成熟DC基本不表达P-, E-选择素, 而分别高表达和低表达L-选择素. 进一步发现, PsL-EGFmAb较对照IL-10对DC表面DC-SIGN表达有抑制作用; 也能抑制细胞内NF-κB基因表达, 并相应抑制或下调DC黏附共刺激分子CD11c, CD83, CD80, CD86及HLA-DR表达, 抑制IL-12基因转录及其合成分泌, 以及抑制DC体外刺激T细胞增殖的能力. 上述结果表明, PsL-EGFmAb对DC分化成熟及功能具有抑制作用, 提示此作用与其抑制作为DC模式识别受体及功能分子DC-SIGN有关, 并可能是通过影响NF-κB信号途径起作用.     

人工寒潮对高血压大鼠P-选择素的影响

目的:探讨人工寒潮对易卒中型肾血管性高血压大鼠(RHRSP)血小板活化影响.方法:健康雄性Sprague Dawley(SD)随机分成三组:高血压组、假手术组、正常对照组,高血压组大鼠按双肾双夹法复制成RHRSP模型;用鼠尾测压仪(HX21型)经尾动脉测量收缩压,肾动脉狭窄术前测量1次,术后每4周测量1次,观察12周,分别与对照组和假手术组比较;12周末对每只大鼠放入人工寒潮箱进行人工寒潮,4小时后舌下静脉取血约2ml.流式细胞仪检测RHRSP全血中p-选择素(CD62p)表达阳性率,取脑组织进行病理学检查.结果:不同时期各组全血中CD62p表达阳性率比较:a.方差分析结果表明:高血压组CD62p表达阳性率显著高于其它2对照组(P＜0.01);b.CD62p表达阳性率、随血压的升高而逐渐增多,与高血压大鼠MAP成正相关关系;c.t检验结果表明:高血压组CD62p表达阳性率在经历人工寒潮后较前显著升高(P＜0.0).结论:高血压大鼠的CD62p表达阳性率较对照组明显增高,在人工寒潮后CD62p表达更高.     

肺炎支原体对宿主细胞黏附机制的研究进展

肺炎支原体通过其末梢尖端结构即黏附细胞器与呼吸道黏膜上皮细胞受体(唾液酸共轭物或糖脂结构域)结合并定植于人体呼吸道,引起原发性非典型性肺炎等疾病。因此,其黏附机制引起了人们的重视。本文着重阐述了肺炎支原体黏附细胞器的形态、结构,黏附素与黏附辅助蛋白的种类、定位、功能及在黏附过程中的协同作用。     

肥胖2型糖尿病患者血清脂联素、E-选择素、可溶性细胞黏附因子-1的表达及其与氧化应激的关系

目的:研究肥胖2型糖尿病患者血清脂联素、E-选择素、可溶性细胞黏附因子-1的表达及其与氧化应激的关系。方法:选择2015年06月至2017年01月在我院治疗的2型糖尿病患者72名,根据患者体重和腰围分为观察组与对照组,观察组为肥胖2型糖尿病患者,对照组为非肥胖2型糖尿病患者。分析两组患者临床指标检测结果及与氧化应激的相关性。结果:观察组血清脂联素(Adiponectin,ADPN)、超氧化物歧化酶(Superoxide Dismutase,SOD)水平[(6.05±1.01)μg/ml vs(7.83±1.25)μg/ml、(72.15±12.04)NU/ml vs(87.66±14.53) NU/ml]均明显低于对照组水平,且观察组E-选择素(Human soluble E-selectin, s E-selectin)、丙二醛(Malondialdehyde; malonic dialdehyde; Propanedial, MDA)、可溶性血管细胞黏附因子-1 (Human soluble vasccular cell adhesion molecule 1, s VCAM-1)、HOMA-胰岛素抵抗指数(Homeostasis model assessment for insulin resistance, HOMA-IR)水平[(66.81±11.10)μg/L vs (55.22±9.05)μg/L、(5.68±0.92)μmol/L vs (4.15±0.62)μmol/L、(1.84±0.25) mg/L vs (1.70±0.24) mg/L、(4.52±1.88) vs(2.23±1.15)]均明显高于对照组(P0.05);观察组患者甘油三酯(Triglyceride,TG)、胆固醇(total cholesterol, TC)、低密度脂蛋白胆固醇(Low-density lipoprotein, LDL-C)显著高于对照组,高密度脂蛋白胆固醇(High-density lipoprotein cholesterol, HDL-C)、糖化血红蛋白(Hemoglobin A1C, HbA1C)明显低于对照组(P0.05)。MDA与空腹血糖(fasting plasma glucose, FPG)、餐后2小时血糖(2 hours postprandial blood glucose, 2Hpg)、HbA1C、TG、TC、LDL-C、s E-selectin、s VCAM-1、HOMA-IR呈正相关关系(P0.05),与HDL3-C、ADPN、SOD呈负相关关系(P0.05);SOD与FPG、2Hpg、Hb A1C、TG、TC、LDL-C、s E-selectin、s VCAM-1、HOMA-IR、MDA呈负相关关系(P0.05),与HDL3-C、ADPN呈正相关关系(P0.05)。结论:肥胖易导致2型糖尿病患者的血清脂联素下降并抑制胰岛素的分泌,可溶性血管细胞黏附分子-1及E-选择素的高表达与肥胖2型糖尿病患者发生氧化应激有关。     

炎症反应中选择素粘附分子与配体间相互作用的研究

在炎症反应中,白细胞在内皮细胞上滚动由选择素分子与其配体分子相互作用所导致,选择素分子有3种,P选择素分子（P—selectin）、E选择素分子（E—selectin）、L选择素分子（L—selectin）,选择素分子与其对应的P-选择素糖蛋白配体-1（PSGL-1）的相互作用起着重要的作用。用等离子共振、流动腔、原子力显微镜等技术能定量分析选择素分子与其配体分子相互作用的动力学反应。     

树突状细胞迁移在肾小管间质炎症中作用及抗黏附干预调节

损伤因素刺激下产生的肾间质炎细胞浸润及肾小管间质炎症免疫反应,是导致和促进肾小管间质早期损伤、病变以及纤维化形成的重要原因。已证明炎症状态下的树突状细胞(DC)肾内迁移及其启动的炎症免疫反应与肾小管间质损害密切相关,既是导致肾间质纤维化形成的重要病理基础,也是肾脏局部免疫病理机制中的关键因素。鉴于选择素等黏附分子介导参与了DC肾内迁移及炎症免疫反应,而针对此的抗黏附调节已取得良好的干预效果,故可能不失为一个新的肾小管间质损伤及纤维化的防治途径和手段。     

当归注射液对急性肺栓塞大鼠P-选择素、抗心磷脂抗体的作用

目的:研究当归注射液对急性肺栓塞大鼠P-、E-选择素及抗心磷脂抗体(ACA)表达的影响。方法:SD大鼠按完全随机设计分为正常对照组(N组),血栓栓塞组(T组),当归治疗组(TA组),各组分1h、4h、8h3个时间点,分别用ELISA、免疫组化法检测大鼠P-、E-选择素及ACA水平。结果:肺组织HE染色N组大鼠肺内炎症细胞数较少。T组、TA组大鼠肺内炎症细胞数分别较N组升高(P0.05),且T组大鼠肺内炎症细胞数随时间延长逐渐增多;血浆ELISA法检测P-、E-选择素结果:T组分别较N组表达增高(P0.05);TA组分别较T组各相应时间点表达降低(P0.05);各组间大鼠血浆ACA的OD值无统计学意义(P0.05),但免疫组化显示TA组大鼠肺组织的P-,E-选择素及ACA表达均降低。结论:急性肺栓塞可引起大鼠肺部炎症细胞浸润,并可能通过P-、E-选择素及ACA释放增加,释放炎症介质加重肺损伤;中药当归注射液可能通过抑制P-、E-选择素及ACA的表达,减轻急性肺栓塞大鼠肺部炎症反应从而减少血栓形成。     

The Synergy of 6-O-Sulfation and N- or 3-O-Sulfation of Chitosan Is Required for Efficient Inhibition of P-Selectin-Mediated Human Melanoma A375 Cell Adhesion

We prepared chitosan sulfated derivatives to address the common structural requirement of the sulfate pattern to block P-selectin-mediated tumor cell adhesion. Our results indicate that 6-O-sulfation of chitosan is indispensable for inhibition of P-selectin binding to human melanoma A375 cells. Furthermore, additional N-sulfation or 3-O-sulfation dramatically enhanced the inhibitory activity of 6-O-sulfated chitosan, suggesting that efficient anti-P-selectin adhesion activity of sulfated saccharides requires the synergy of 6-O-sulation and N- or 3-O-sulfation in glucosamine units.     

Borrelia Burgdorferi Upregulates the Adhesion Molecules E-selectin, P-selectin, ICAM-1 and VCAM-1 on Mouse Endothelioma Cells in vitro

In order to obtain more information on processes leading to Borrelia burgdorferi-induced inflammation in the host, we have developed an in vitro model to study the upregulation of cell surface expression of adhesion molecules on endothelial cells by spirochetes. A mouse endothelioma cell line, derived from brain capillaries, bEnd3, was used as indicator population. bEnd3 cells were incubated with preparations of viable, inactivated or sonicated spirochetes and the expression of E-selectin, P-selectin, ICAM-1 and VCAM-1 was monitored by immunocytochemistry and quantified by cell surface ELISA. We show that all three spirochetal preparations are able to upregulate cell surface expression of E-selectin, P-selectin, ICAM-1 and VCAM-1 on bEnd3 cells in a dose-dependent manner. The kinetics of cell surface expression of the individual adhesion molecules in the presence of Borrelia burgdorferi showed maxima at about 50 h of incubation or later; this was distinct from results obtained with sonicated-preparations of Escherichia coli bacteria or with enterobacterial LPS where peak expression was observed between 4 h and 16 h. The fact that Borrelia burgdorferi does not contain conventional LPS suggests that the mode of induction of adhesion molecules on endothelial cells is influenced by the phenotype of bacteria. At the peak of spirochete-induced cell surface expression of adhesion molecules (≈50 h), bEnd3 cells were found to bind cells of a VLA-4⁺ B lymphoma line (L1-2) much more efficiently than untreated control cells. The binding of L1-2 cells to presensitized bEnd3 cells was significantly inhibited (more than 75%) in the presence of monoclonal antibodies to both VLA-4 and its endothelial counterreceptor VCAM-1. These findings demonstrate that Borrelia burgdorferi organisms are able to induce functionally active adhesion molecules on endothelial cells in vitro and suggest that E-selectin, P-selectin, ICAM-1 and VCAM-1 play an important role in the pathogenesis of spirochetal infection.     

P-selectin activates integrin-mediated colon carcinoma cell adhesion to fibronectin

During hematogenous cancer metastasis, tumor cells separate from a primary mass, enter the bloodstream, disperse throughout the body, migrate across vessel walls, and generate distant colonies. The later steps of metastasis superficially resemble leukocyte extravasation, a process initiated by selectin-mediated cell tethering to the blood vessel wall followed by integrin-mediated arrest and transendothelial migration. Some cancer cells express P-selectin ligands and attach to immobilized P-selectin, suggesting that these cells can arrest in blood vessels using sequential selectin- and integrin-mediated adhesion, as do leukocytes. We hypothesize that selectin binding may regulate subsequent integrin-mediated steps in metastasis. Using a model system of cultured Colo 320 human colon adenocarcinoma cells incubated with soluble P-selectin-IgG chimeric protein, we have found that P-selectin can stimulate activation of the alpha(5)beta(1) integrin resulting in a specific increase of adhesion and spreading of these cells on fibronectin substrates. P-selectin binding also induced activation of p38 mitogen-activated protein kinase (p38 MAPK) and phosphatidylinositol 3-kinase (PI3-K). PI3-K inhibitors blocked P-selectin-mediated integrin activation, cell attachment, and cell spreading. Inhibition of p38 MAPK activation blocked cell spreading, but not cell attachment. P-selectin binding also resulted in formation of a signaling complex containing PI3-K and p38 MAPK. These results suggest that P-selectin binding to tumor cells can activate alpha(5)beta(1) integrin via PI3-K and p38 MAPK signaling pathways leading to increased cell adhesion. We propose that P-selectin ligands are important tumor cell signaling molecules that modulate integrin-mediated cell adhesion in the metastatic process.     

Borrelia Burgdorferi Upregulates the Adhesion Molecules E-selectin,P-selectin,ICAM-1 and VCAM-1 on Mouse Endothelioma Cells in vitro

In order to obtain more information on processes leading to Borrelia burgdorferi-induced inflammation in the host, we have developed an in vitro model to study the upregulation of cell surface expression of adhesion molecules on endothelial cells by spirochetes. A mouse endothelioma cell line, derived from brain capillaries, bEnd3, was used as indicator population. bEnd3 cells were incubated with preparations of viable, inactivated or sonicated spirochetes and the expression of E-selectin, P-selectin, ICAM-1 and VCAM-1 was monitored by immunocytochemistry and quantified by cell surface ELISA. We show that all three spirochetal preparations are able to upregulate cell surface expression of E-selectin, P-selectin, ICAM-1 and VCAM-1 on bEnd3 cells in a dose-dependent manner. The kinetics of cell surface expression of the individual adhesion molecules in the presence of Borrelia burgdorferi showed maxima at about 50 h of incubation or later; this was distinct from results obtained with sonicated-preparations of Escherichia coli bacteria or with enterobacterial LPS where peak expression was observed between 4 h and 16 h. The fact that Borrelia burgdorferi does not contain conventional LPS suggests that the mode of induction of adhesion molecules on endothelial cells is influenced by the phenotype of bacteria. At the peak of spirochete-induced cell surface expression of adhesion molecules (≈50 h), bEnd3 cells were found to bind cells of a VLA-4⁺ B lymphoma line (L1-2) much more efficiently than untreated control cells. The binding of L1-2 cells to presensitized bEnd3 cells was significantly inhibited (more than 75%) in the presence of monoclonal antibodies to both VLA-4 and its endothelial counterreceptor VCAM-1. These findings demonstrate that Borrelia burgdorferi organisms are able to induce functionally active adhesion molecules on endothelial cells in vitro and suggest that E-selectin, P-selectin, ICAM-1 and VCAM-1 play an important role in the pathogenesis of spirochetal infection.     

The Apical Lamina and its Role in Cell Adhesion in Sea Urchin Embryos

The hyaline layer (HL) is an extracellular matrix surrounding sea urchin embryos which has been implicated in a cell adhesion and morphogenesis. The apical lamina (AL) is a fibrous meshwork that remains after removal of hyalin from the HL and the fibropellins (FP) are glycoproteins thought to be the principal components of the AL. Using anti-FP antibodies (AL-1 and AL-2) we report immunoprecipitations and affinity purifications yield a high molecular weight complex comprised of the FP glycoproteins. The three components form a complex, stabilized by disulphide cross-linking and have stochiometric ratios of 2 FPIa molecules to 1 each of FPIb and FPIII. Pulse chase experiments indicate all 3 FP's are synthesized throughout development with peaks in synthesis during cleavage and a sustained peak beginning at hatching. Using immunogold and immunoperoxidase localization, the FP localize to a fibrillar complex forming the innermost layer of the HL. In cell adhesion experiments, cells adhere to affinity purified FP in a temperature, time and concentration dependent manner. Cell adhesion to Fp is about 70% of that seen when hyalin is used as a substrate. Pretreating with AG1 and AG2 reduces in vitro cell adhesion by about 65%. We conclude FP's form a fibrillar complex, which is synthesized throughout early development and functions, with other components of the HL, as a substrate for cell adhesion.     

EphB/ephrinB Signaling in Cell Adhesion and Migration

Eph receptors and their ligands, ephrins, represent the largest group of the receptor tyrosine kinase (RTK) family, and they mediate numerous developmental processes in a variety of organisms. Ephrins are membrane-bound proteins that are mainly divided into two classes: A class ephrins, which are linked to the membrane by a glycosylphosphatidylinositol (GPI) linkage, and B class ephrins, which are transmembrane ligands. Based on their domain structures and affinities for ligand binding, the Eph receptors are also divided into two groups. Trans-dimerization of Eph receptors with their membrane-tethered ligands regulates cell-cell interactions and initiates bidirectional signaling pathways. These pathways are intimately involved in regulating cytoskeleton dynamics, cell migration, and alterations in cellular dynamics and shapes. The EphBs and ephrinBs are specifically localized and modified to promote higher-order clustering and initiate of bidirectional signaling. In this review, we present an in-depth overview of the structure, mechanisms, cell signaling, and functions of EphB/ephrinB in cell adhesion and migration.     

Heterogeneity of Soluble Neural Cell Adhesion Molecule

Soluble neural cell adhesion molecule (NCAM) from rat brain neuronal cell culture media consists predominantly of a polypeptide of Mr approximately 115,000. Minor amounts of a polypeptide of Mr approximately 180,000 and two inconsistently appearing components of Mr 160,000 and 145,000 are also observed. The Mr 115,000 component is derived from the neuronal membrane NCAM components NCAM-A of Mr 190,000, NCAM-B of Mr 140,000, or both. Thus, as a part of the catabolism of membrane NCAM-A plus -B, a minor fraction is posttranslationally cleaved and recovered in the media as discernible soluble NCAM polypeptides. The half-life of membrane NCAM-A plus -B is less than 24 h. Astrocyte culture media contains a predominant soluble NCAM component of Mr 120,000 derived from membrane-associated NCAM-C. A close comparison of deglycosylated soluble NCAM from astrocyte and neuronal cultures showed a small but consistent difference in Mr, a result suggesting that different NCAM polypeptides are released from the membrane of neurons and astrocytes. In contrast to the Mr 115,000-120,000 NCAM polypeptides, the Mr 180,000 polypeptide from neuronal culture media does not seem to be derived from membrane-attached NCAM and may therefore represent a secreted NCAM isoform.     

神经细胞粘连分子和多聚唾液酸在神经发育和再生中的作用

神经系统的形成依赖于细胞间的互相粘连。本文综述了神经细胞粘连分子（ＮＣＡＭ）及其多聚唾液酸（ＰＳＡ）组份对神经发育和再生的作用。ＮＣＡＭ的基本功能是介导细胞粘连,ＰＳＡ则由于其特殊的分子结构而降低细胞间的粘连。研究表明,鸡胚的发育过程中,ＰＳＡ含量在三个关键时期表达的高低决定了运动神经元能否准确地识别和支配肌肉。成年大鼠周围神经损伤后,肌肉内ＮＣＡＭ含量的高低决定于该肌肉的神经支配状况。成年大鼠脑内,切断内嗅皮层与海马的神经联系,发现齿回外分子层ＰＳＡ含量显著增加,并至少可持续６０天。已有的研究资料提示在去神经靶区域ＰＳＡ的重新表达可能有利于移植神经元轴突的生长并与宿主重建突触联系。