神经调节因子Neuregulin-1(Nrg1)调节U87-MG细胞的黏附分子L1表达及促迁移作用

目的研究神经调节因子Neuregulin-1(Nrg1)对人胶质母细胞瘤U87-MG细胞中细胞黏附分子L1表达及细胞迁移的影响。方法给予U87-MG细胞重组Nrg1α(rNrg1α,2.5 nmol/L)24和48 h,RT-PCR观察L1 mRNA表达;给予细胞rNrg1α或rNrg1β(2.5 nmol/L)48 h,Western blot检测L1蛋白水平。用Nrg1 siRNA处理细胞,Western blot观察L1蛋白水平,用细胞划伤实验观察细胞迁移。结果 Nrg1α可促进L1 mRNA表达;与0 nmol/L组相比,Nrg1α及Nrg1β(2.5 nmol/L)均可显著增加L1蛋白水平(P<0.01,P<0.05)。与对照siRNA相比,Nrg1 siRNA明显降低Nrg1表达,并伴有L1表达下降。Nrg1 siRNA处理细胞划伤16 h,划伤边缘细胞Nrg1α、Nrg1β及L1荧光信号降低,细胞迁移减弱。结论 Nrg1可调节U87-MG细胞L1表达,其参与细胞迁移可能与提高L1表达有关。     

hCEACAM1介导淋病奈瑟菌对COS-1细胞的黏附

目的 研究人癌胚抗原相关细胞黏附因子1(hCEACAM1)在淋病奈瑟菌黏附宿主细胞过程中的作用.方法 将hCEACAM1 cDNA置于hCD46启动子和兔β-球蛋白第2内含子之后,构建重组真核表达载体pCDPGICEA1.转染COS-1细胞,G418筛选和流式细胞术分选稳定表达hCEACAM1的基因转染细胞.细菌黏附实验检测淋病奈瑟菌对基因转染COS-1细胞的黏附.结果 在hCD46启动子和兔β-球蛋白第2内含子的作用下,hCEACAM1 cDNA在COS-1细胞获得高效表达,淋病奈瑟菌可以黏附表达hCEACAM1的COS-1细胞.结论 hCEACAM1可以介导淋病奈瑟菌对动物细胞的黏附,可能是淋病奈瑟菌特异性感染人体的一种重要受体,可用来制备淋病奈瑟菌感染的相应转基因动物模型.     

白细胞介素1与大鼠神经细胞NMDA受体关系的研究

观察了ＩＬ－１β对ＮＭＤＡ受体活性及其ｍＲＮＡ表达的影响。结果表明，ＩＬ－１β在１－２５Ｕ／ｍｌ浓度范围内可剂量依赖地提高ＮＭＤＡ受体的活性和明显促进培养胚胎大鼠大脑皮层神经元ＮＭＤＡ１型受体的ｍＲＮＡ的表达，并存在一定的剂量、时间效应关系。     

神经细胞黏附分子1和骨调蛋白在神经管畸形中的变化

目的初步探究神经细胞黏附分子1和骨调蛋白在神经管畸形中的变化。方法20只健康成年SD孕大鼠随机分为正常对照组和神经管畸形实验组,每组10只。通过胃饲维甲酸建立胚胎大鼠神经管畸形模型,检查了神经管畸形鼠体重的变化;用HE染色观察神经管畸形鼠神经管结构的变化;通过Western blot分析神经管畸形鼠组织中神经细胞黏附分子1和骨调蛋白的变化。结果神经管畸形鼠形态偏小,体质量为(0.34±0.45)g,明显低于正常对照组(0.53±056)g。胚胎鼠在第9天神经管处于未闭合状态,在第11天已完全闭合。胚胎第9天和11天神经管畸形大鼠的神经细胞黏附分子1比正常组表达均明显增加(P0.01)。骨调蛋白在胚胎第9 d神经管畸形大鼠中的表达比正常明显增高(P0.01),但在胚胎第11天的表达与正常相比没有差异(P0.05)。结论神经细胞黏附分子1和骨调蛋白的变化可能与神经管畸形形成有密切关系。     

神经营养因子信号转导与神经细胞凋亡的分子机制

细胞凋亡(Apoptosis)是一种程序化的细胞死亡过程,其中神经细胞的凋亡对胚胎期神经系统的生长、发育、分化、成熟及生后各种原因所致的脑损伤,神经退行性疾病的发生都起着至关重要的作用。神经营养因子(Neurotrophins,NTS)通过其与相应靶细胞膜受体的活化而引发相关信使分子的级联激活而减缓神经细胞凋亡、促进神经细胞的存活,发挥其生物学功能。对NTS家族信号转导与神经细胞凋亡的分子机制的认识有助于早期干预和治疗各种原因所致神经发育残障,脑损伤及神经退性行疾病。     

细胞间黏附分子-1的研究概况及临床意义

细胞间黏附分子-1( ICAM-1)是一种细胞表面的跨膜糖蛋白,可介导细胞与细胞间或细胞与细胞外基质之间的相互作用.ICAM-1广泛地参与细胞黏附、炎症的发生发展、信号转导和肿瘤转移等多种重要的生理及病理过程.在临床上,ICAM-1可作为多种炎症或肿瘤发展和预后的重要生物标记物之一.以ICAM-1为靶点的药物或能预防和治疗多种急、慢性炎症引起的组织损伤和肿瘤等.     

骨髓基质细胞在传代与诱导分化为神经细胞过程中hes1和mash1基因的表达变化

目的:探讨骨髓基质细胞(BMSCs)在传代培养与诱导分化为神经细胞过程中hes1和mash1基因的表达变化及作用。方法:采用全骨髓培养法体外分离培养获得BMSCs,倒置显微镜下观察其形态变化,应用半定量RT-PCR技术分析hes1和mash1基因在传代和诱导分化为神经细胞过程中的动态时序表达。结果:诱导后细胞形态出现神经元样改变。hes1在第3代BMSCs诱导后(P)第1日表达下降,之后第3日表达增加。mash1在BMSCs传至第5代时高表达,随后急剧下降;P3的BMSCs诱导后表达逐日增加。结论:hes1和mash1基因在BMSCs传代与诱导分化为神经细胞过程中可能起重要作用。     

恒河猴移植肝组织内细胞间黏附分子1与急性排斥反应的关系

背景：在急性排斥反应发生时会伴有移植组织中细胞间黏附分子1表达水平的增高。 目的：探讨恒河猴移植肝组织内细胞间黏附分子1与急性排斥反应的关系。 方法：建立恒河猴同种异体肝移植模型,随机分为实验组(移植后不给予抗排斥处理)和对照组(移植中及移植后均给予抗排斥处理)。 结果与结论：实验组移植后24,72 h血清丙氨酸氨基转移酶及血清总胆红素水平明显高于对照组(P < 0.05或< 0.001)。移植后12 h实验组移植肝即表现为轻度急性排斥反应,说明急性排斥反应时肝功能变化滞后于肝组织病理学检查,移植后24,72 h表现为中重度急性排斥反应。移植后6 h实验组肝组织中血管内皮细胞、肝细胞膜、胆管上皮细胞上细胞间黏附分子1的表达呈持续增强,并显著高于对照组(P < 0.05),随细胞间黏附分子1的表达增强,排斥反应加剧,说明在急性排斥反应早期,肝功能、病理学仅有轻微改变时,细胞间黏附分子1水平即显著升高。提示移植肝组织中细胞间黏附分子1表达的检测对肝移植后急性排斥反应的早期诊断具重要意义。     

Immunocytochemical localization of cell adhesion molecule L1 in developing rat pyramidal tract

L1 is a representative of a family of carbohydrate neural cell adhesion molecules. The expression of L1 was studied during postnatal development of the rat pyramidal tract by immunohistology using polyclonal antibodies to L1 in spinal cord cervical intumescences. On postnatal day 1 (P1), L1 immunoreactivity was present in the entire dorsal funiculus, consisting of the ascending fasciculus gracilis and fasciculus cuneatus and the descending pyramidal tract. At that time the cervical pyramidal tract contains the first outgrowing corticospinal axons. At P4 both the fasciculus gracilis and the pyramidal tract are immunoreactive whereas the fasciculus cuneatus is negative. At P10 the pyramidal tract is intensely labelled whereas both ascending bundles are negatively stained. In the period between P4 and P10 the pyramidal tract is characterized by a massive outgrowth of corticospinal axons. During pyramidal tract myelination, between P10 and the end of the third postnatal week (P21), L1 immunoreactivity is progressively reduced. These observations suggest that L1 may play a prominent role in outgrowth, fasciculation and the onset of myelination of rat pyramidal tract axons. The differential L1 immunoreactivity of the pyramidal tract and the earlier developing ascending systems in rat dorsal funiculus indicate that this polyclonal antiserum is a useful differentiating marker for outgrowing fibre tracts.     

L1 cell adhesion molecule as a novel independent poor prognostic factor in gallbladder carcinoma

Gallbladder carcinoma is a lethal malignancy and is hard to cure by current treatment. Thus, identification of molecular prognostic markers to predict gallbladder carcinoma as therapeutic targets is urgently needed. Recent studies have demonstrated that L1 cell adhesion molecule is associated with the prognosis of variable malignancy. Here, we investigated L1 cell adhesion molecule expression in gallbladder carcinoma and its prognostic significance. In this study, we examined L1 cell adhesion molecule expression in tumor specimens from 69 patients with gallbladder carcinoma by immunohistochemistry and analyzed the correlation between L1 cell adhesion molecule expression and clinicopathologic factors or survival. L1 cell adhesion molecule was not expressed in the normal epithelium of the gallbladder but in 63.8% of gallbladder carcinomas, remarkably at the invasive front of the tumors. In addition, L1 cell adhesion molecule expression was significantly associated with high histologic grade, advanced pathologic T stage and clinical stage, and positive venous/lymphatic invasion. Multivariate analyses showed that L1 cell adhesion molecule expression (hazard ratio, 3.503; P = .028) and clinical stage (hazard ratio, 3.091; P = .042) were independent risk factor for disease-free survival. L1 cell adhesion molecule expression in gallbladder carcinoma was significantly correlated with tumor progression and unfavorable clinicopathologic features. L1 cell adhesion molecule expression was an independent poor prognostic factor for disease-free survival in patients with gallbladder carcinoma. Taken together, our findings suggest that L1 cell adhesion molecule expression could be used as a novel prognostic factor for patient survival and might be a potential therapeutic target in gallbladder carcinomas.     

The clinical spectrum of mutations in L1, a neuronal cell adhesion molecule

Mutations in the gene encoding the neuronal cell adhesion molecule L1 are responsible for several syndromes with clinical overlap, including X-linked hydrocephalus (XLH, HSAS), MASA (mental retardation, aphasia, shuffling gait, adducted thumbs) syndrome, complicated X-linked spastic paraplegia (SP 1), X-linked mental retardation-clasped thumb (MR-CT) syndrome, and some forms of X-linked agenesis of the corpus callosum (ACC). We review 34 L1 mutations in patients with these phenotypes. © 1996 Wiley-Liss, Inc.     

Expression of the neural cell adhesion molecule (CD56) by human myeloma cells.

Recent studies in multiple myeloma indicate that molecules associated with different haematopoietic lineages may be expressed aberrantly by myeloma cells. In order to investigate this phenomenon further, we studied the immunophenotype of bone marrow cells from 21 patients with multiple myeloma using a panel of monoclonal antibodies against T,B, myelomonocytic, and natural killer (NK)-cell antigens. Leu-19/NKH1 (CD56), a molecule identical to N-CAM, which is normally expressed by neuroectodermal and NK cells, was found in 13 patients (62%). Dual-parameter flow cytometry was used to correlate N-CAM positivity with DNA aneuploidy or cytoplasmic immunoglobulin expression as markers of myeloma cells. When N-CAM was found positive, other haematopoietic antigens were expressed only in three out of 13 cases (23%). In contrast, myeloma cells not expressing N-CAM frequently exhibited pre-B cell markers, myeloid antigen, and HLA-DR, respectively (seven out of eight cases, 88%). Six out of eight N-CAM-negative myelomas were of the IgG lambda isotype, otherwise no clearcut association with basic clinical and laboratory parameters was noted. We conclude that N-CAM expression is a common finding in multiple myeloma. Whether its expression and the observed antigenic heterogeneity is just a manifestation of malignancy or N-CAM may play a role in the biology of multiple myeloma regarding tumour cell spread, remains to be explained.     

神经细胞黏附分子对小鼠骨髓间充质干细胞黏附、迁移及细胞形态的影响

目的探讨神经细胞黏附分子(NCAM)对小鼠骨髓间充质干细胞(BMSCs)黏附、迁移及细胞形态的影响。方法从野生型小鼠和NCAM基因敲除小鼠中分离、培养BMSCs,Western blot和免疫荧光标记检测NCAM的表达;划痕实验和黏附实验分别检测细胞迁移和黏附能力;倒置显微镜下观察细胞形态;Western blot检测β1整联蛋白、E-cadherin、β-catenin和N-cadherin的表达。结果 NCAM基因敲除后细胞的迁移能力和黏附能力明显降低,β1整联蛋白的表达下调(P0.01),BMSCs形态由不规则形变为扁平形,且成簇增殖,上皮细胞标记蛋白E-cadherin和β-catenin的表达显著上调(P0.05),而间质细胞标记蛋白N-cadherin的表达下调(P0.01)。结论NCAM通过调控β1整联蛋白的表达影响BMSCs的黏附和迁移,同时NCAM可能对BMSCs的间质上皮转化起负调控作用。     

Overexpression of L1 cell adhesion molecule correlates with aggressive tumor progression of patients with breast cancer and promotes motility of breast cancer cells

Background and purpose: L1 cell adhesion molecule (L1CAM) has been observed to be aberrantly expressed and implicated in progression of several types of human cancers. However, its roles in breast cancer have not been fully elucidated. In this study, we aimed to investigate the clinical significance of L1CAM in human breast cancer and to validate whether it participates in cancer cell migration and invasion. Methods: Immunohistochemical analysis of 100 breast cancer and matched non-cancerous breast tissues was performed to detect the expression and sub-cellular localization of L1CAM protein. Its associations with clinicopathological characteristics of breast cancer patients were statistically analyzed and its phenotypic effects were also evaluated in vitro. Results: Of the 100 breast cancer patients, 89 (89.0%) were positive for L1CAM immunostaining localized in the membrane of cancer cells. The immunoreactive scores of L1CAM protein in breast cancer tissues were significantly higher than those in matched non-cancerous breast tissues (P<0.05). Chi-Square analysis showed the significant associations between L1CAM overexpression and high tumor stage (P=0.01), advanced tumor grade (P=0.03), positive lymph node metastasis (P=0.01) and tumor recurrence (P=0.01) in breast cancer patients. Moreover, we found that RNA interference-mediated knockdown of L1CAM could inhibit the migration and invasion abilities of breast cancer cells in vitro. Conclusions: Our results suggest that the overexpression of L1CAM may be related to several established markers of poor prognosis in breast cancer patients. L1CAM might be a potential therapeutic target against metastatic breast cancer.     

Missense mutations in the extracellular domain of the human neural cell adhesion molecule L1 reduce neurite outgrowth of murine cerebellar neurons

Mutations in L1CAM, the gene encoding the transmembrane multifunctional neuronal adhesion molecule L1, are associated with neurodevelopmental disorders including X-linked hydrocephalus and mental retardation. Some amino acid substitutions in various extracellular domains of L1 are known to affect posttranslational processing of the protein or its homophilic and heterophilic interactions. It is largely unknown, however, how these mutations result in neurodevelopmental disturbances and whether the effects of mutations on neurodevelopment can be modeled in vitro. We stably expressed full-length human wild type L1 and the known pathogenic missense mutations I179S, R184W, Y194C, and C264Y in NIH-3T3 cells. L1 protein synthesis, glycosylation pattern, and subcellular localization were analyzed. Neurite outgrowth of primary murine cerebellar neurons was measured after 23 hrs of co-cultivation using transfected NIH-3T3 cells as substrate. Like wild type L1, L1 protein with I179S or Y194C mutations was localized on the surface of the transfected substrate cells, but this was not the case with R184W or C264Y mutations. All four mutations were associated with reduced stimulation of neurite outgrowth. Measurement of neurite outgrowth on transfected substrate cells may be a suitable model for studying neurodevelopmental disturbances.     

Potentiation of a weakly active ricin A chain immunotoxin recognizing the neural cell adhesion molecule.

A ricin A chain immunotoxin, SEN36-ricin A chain, directed against the neural cell adhesion molecule (N-CAM) had no selective cytotoxic activity against three different small cell lung cancer (SCLC) cell lines in tissue culture despite expression of the target antigen on more than 98% of cells in each line detected by indirect immunofluorescence. Treatment of the SW2 SCLC cell line with suramin and interferons alpha and gamma increased the level of N-CAM expression only slightly and had no significant effect on the cytotoxic activity of the SEN36 immunotoxin. In the presence of the carboxylic ionophore monensin at a concentration of 0.1 microM, the toxicity of SEN36-ricin A chain to the SW2 cell line was enhanced by 12,000-fold. In contrast, lysosomotropic amines showed little or no potentiation of activity, suggesting that lysosomal degradation was not the major factor limiting the action of the anti-N-CAM immunotoxin. The findings of this study indicate that ricin A chain immunotoxins directed against N-CAM on SCLC are unlikely to have sufficient activity to be useful therapeutic agents in the absence of potentiating agents such as monensin, which can interfere with the normal intracellular pathways of antigen routing.