Human Trophoblast Cell Adhesion to Extracellular Matrix Protein,Entactin

PROBLEM: Trophoblast interaction with endometrial extracellular matrix (ECM) is crucial during human embryo implantation and placentation. Entactin, a ubiquitous basement membrane glycoprotein, plays a central role in ECM assembly, cell attachment, and chemotaxis. The present study was conducted to examine the possible role of entactin in promoting human trophoblast adhesion. METHODS: Using an extended life span first trimester trophoblast cell line HTR-8/SVneo (HTR) and a cell adhesion assay, we measured the adherence of human first trimester trophoblasts to recombinant entactin and its domains. Also, we used flow cytometry and indirect immunofluorescence to detect the presence of integrins that may be involved in human trophoblast-entactin interaction; these methods were used to analyze HTR cells, as well as tissue sections and freshly isolated human trophoblasts from first trimester and term placenta. RESULTS: We found that first trimester trophoblast cells were highly adherent to entactin and its E and G2 domains but not to G1 or G3 domains. Using indirect immunofluorescence and flow cytometry, we found that both β1 and β3 integrin subunits were expressed on the surface of HTR trophoblast cells adhering to entactin; in contrast, β2 and β4 integrin subunits were not detected. In addition, we found that αvβ3 was expressed on freshly isolated villous cytotrophoblasts and cytotrophoblast and syncytiotrophoblasts in tissue sections from term placenta. The β3 integrin subunit was expressed in cytotrophoblasts and syncytiotrophoblasts in villi of first trimester placental tissue sections. CONCLUSION: Recombinant entactin promotes human trophoblast cell adhesion through both its E and G2 domains and these specific adhesive interactions may be mediated by β1 and/or β3 class integrins.     

Expression of Cell Adhesion Molecules in the Extravillous Trophoblast Is Altered in IUGR

PROBLEM: The invasion of trophoblast cells into the uterine wall and its arterial system is essential for the normal development of pregnancy. Cell adhesion molecules (CAM), such as the immunoglobulin superfamily and integrins, play a crucial role in a number of immunological reactions and in the invasion of the human trophoblast. Intrauterine growth restriction (IUGR) has been associated with abnormal trophoblast invasion. Therefore, the expression of CAM in the extravillous trophoblast of pregnancies complicated by IUGR might be different from normal pregnancies. METHOD OF STUDY: Normal (n = 21) and IUGR (n = 19) placentas were collected and stored at ?70°C. Immunohistochemistry (avidin-biotin complex peroxidase-doublestaining) of frozen tissue sections was performed using antibodies specific for the immunoglobulin superfamily vascular adhesion molecule-1 (VCAM-1; CD 106), intercellular adhesion molecule (ICAM-1) (CD 54), ICAM-2 (CD 102), ICAM-3 (CD 50), the integrins α2β1, α3β1, α4β1, α5β1, α6β1 and cytokeratin. The percentage of immunopositive extravillous trophoblast cells (EVT) and the intensity of the immunoreactivity for the various CAM and integrin antibodies was assessed. RESULTS: In IUGR placentas, there was less expression of VCAM-1 (CD 106), α2β1, α3β1, and α5β1 (P < 0.05) in the extravillous trophoblast than in normal pregnancies. Finally we observed for the first time that ICAM-3 was expressed on EVT and that its expression was markedly up-regulated in the EVT of IUGR placentas. No differences were found for ICAM-1 (CD 54), ICAM-2 (CD 102), α4β1 and α6β1. CONCLUSION: Our data show that there are significant differences in the expression of cell adhesion molecules of the extravillous trophoblast from IUGR and normal pregnancies. These differences might reflect changes in the immunological reactions and cell-cell interactions between mother and the developing fetus which could interfere with fetal growth.     

Midtrimester Amniotic Fluid Tumor Necrosis Factor-Alpha Does Not Predict Small-for-Gestational-Age Infants

PROBLEM: To evaluate the independent ability of midtrimester amniotic fluid tumor necrosis factor-alpha (TNF-α) in the prediction of small-for-gestational-age (SGA) infants. METHOD OF STUDY: In this case-control study, patients delivering a SGA infant were matched with controls based on GA at delivery, maternal age, race, and parity. Patients with immune disease, chronic hypertension, diabetes, asthma, congenital hearts disease, multiple gestation, and fetal anomalies were excluded. Amniotic fluid samples were immunoassayed for TNF-α. Potential confounding variables evaluated were maternal serum alpha-fetoprotein level, smoking history, pregnancy induced hypertension, and neonatal gender. Statistical analysis included Fisher's exact test and ANOVA after log transformation with P < 0.05 considered significant. RESULTS: Eighteen patients delivered SGA neonates and were matched with 41 controls. No significant differences were identified in the confounding variables between patients with SGA neonates and controls. Amniotic fluid TNF-α levels were not significantly different between patients subsequently delivering SGA neonates and controls [median 7.63 (range 0.25-16.1) pg/mL versus 9.39 (0.25–66.9) pg/mL, P = 0.8]. CONCLUSIONS: Midtrimester amniotic fluid TNF-α levels are not predictive of SGA neonates when compared with controls matched for gestational age at delivery.     

Distinct Effects of RGD-glycoproteins on Integrin-Mediated Adhesion and Osteogenic Differentiation of Human Mesenchymal Stem Cells

The detailed interactions of mesenchymal stem cells (MSCs) with their extracellular matrix (ECM) and the resulting effects on MSC differentiation are still largely unknown. Integrins are the main mediators of cell-ECM interaction. In this study, we investigated the adhesion of human MSCs to fibronectin, vitronectin and osteopontin, three ECM glycoproteins which contain an integrin-binding sequence, the RGD motif. We then assayed MSCs for their osteogenic commitment in the presence of the different ECM proteins.As early as 2 hours after seeding, human MSCs displayed increased adhesion when plated on fibronectin, whereas no significant difference was observed when adhering either to vitronectin or osteopontin. Over a 10-day observation period, cell proliferation was increased when cells were cultured on fibronectin and osteopontin, albeit after 5 days in culture. The adhesive role of fibronectin was further confirmed by measurements of cell area, which was significantly increased on this type of substrate. However, integrin-mediated clusters, namely focal adhesions, were larger and more mature in MSCs adhering to vitronectin and osteopontin. Adhesion to fibronectin induced elevated expression of α₅-integrin, which was further upregulated under osteogenic conditions also for vitronectin and osteopontin. In contrast, during osteogenic differentiation the expression level of β₃-integrin was decreased in MSCs adhering to the different ECM proteins. When MSCs were cultured under osteogenic conditions, their commitment to the osteoblast lineage and their ability to form a mineralized matrix in vitro was increased in presence of fibronectin and osteopontin.Taken together these results indicate a distinct role of ECM proteins in regulating cell adhesion, lineage commitment and phenotype of MSCs, which is due to the modulation of the expression of specific integrin subunits during growth or osteogenic differentiation.     

丹参多酚酸盐对ApoE基因敲除小鼠血清TNF-α的影响

目的:观察中药丹参多酚酸盐(salvianolate)对C57BL/6JApoE基因敲除小鼠血清肿瘤坏死因子(tumor necrosis factor-α, TNF-α)的影响,以探讨其抗动脉粥样硬化的可能机制.方法:给8周龄雄性C57BL/6J ApoE基因敲除小鼠喂食高脂饮食,腹腔注射丹参多酚酸盐,随机将其分为模型组(仅腹腔注射生理盐水)、丹参多酚酸盐低剂量(60mg/kg)组、中剂量(120mg/kg)组、高剂量(240mg/kg)组,每组12只,共50只;正常对照组(即C57BL/6J野生型小鼠)10只.32周末时处死各组小鼠,留取血清,采用放射免疫分析检测各组小鼠血清TNF-α水平.结果:32周末时,随丹参多酚酸盐剂量的增加,ApoE基因敲除小鼠血清TNF-α浓度逐渐降低,丹参多酚酸盐各剂量组血清TNF-α水平均明显低于模型组(P均＜0.01);丹参多酚酸盐低剂量组与正常对照组比较,无统计学意义(P＞0.05),余两组与正常组比较,有明显统计学意义(P均＜0.01);丹参多酚酸盐各浓度组之间亦有明显差异(P均＜0.01).结论:各剂量组丹参多酚酸盐均能够降低ApoE基因敲除小鼠血清TNF-α水平,随剂量增加,减低越明显,说明丹参多酚酸盐能够抑制动脉粥样硬化炎症反应,可能是其抗动脉粥样硬化的作用机制之一.     

Immunodetection of Cell Adhesion Molecules in Rat Sertoli Cell Cultures

PROBLEM: The presence of cell adhesion molecules (CAMs) in Sertoli cells has not been explored extensively. The expression of CAMs involved in cell-matrix and cell-to-cell interactions in Sertoli cell cultures was examined. METHOD OF STUDY: Immunohistochemical and Western blot techniques were applied to rat Sertoli cell cultures using specific antibodies to α₃, α₅, and α₆ integrin subunits; NCAM; and Cadherins. RESULTS: Expression of α₃ and α₆ integrin subunits (mainly laminin receptors) and lack of expression of α₅ integrin subunit (fibronectin receptor) was observed in Sertoli cells by immunohistochemistry. These cells also expressed neural CAM (NCAM) and N-cadherin. By Western blot analysis, Sertoli cell extracts reacted with antibodies to α₃ integrin subunit revealed a band approximately 130 kDa, whereas no expression of α5 integrin subunit was detected. Cell extracts incubated with antibodies to pan Cadherin exhibited a band approximately 120 kDa, whereas bands of 180, 140, and 120 kDa were observed with antibodies to NCAM. CONCLUSION: New data about the expression of receptors for extracellular matrix proteins (α₃ and α₆ integrin subunits) as well as cell-to-cell adhesion molecules (NCAM and Cadherins) are reported in rat Sertoli cell cultures.     

人绒毛膜滋养层细胞的分离纯化及鉴定

目的建立一种简便易行、经济有效的纯化培养滋养层细胞的方法.方法:取孕6-8w的正常绒毛组织10例,采用胰蛋白酶消化法分离细胞,将细胞随机分为两组(各5例),一组用淋巴细胞分层液进行纯化,另一组未纯化,最后用含15%胎牛血清的培养基培养细胞.用免疫细胞化学法进行细胞纯度鉴定.结果本纯化的细胞阳性率为(68.6 2±2.69)%,纯化后的细胞阳性率为(91.60±1.55)%,两者之间的差异具极显著性意度( P<0.001).结论该法简便易行,经济有效,可获得纯度较高、合乎试验要求的细胞滋养层细胞.     

Salmonella Flagellin Induces Tumor Necrosis Factor Alpha in a Human Promonocytic Cell Line

During infection of the gastrointestinal tract, salmonellae induce cytokine production and inflammatory responses which are believed to mediate tissue damage in the host. In a previous study, we reported that salmonellae possess the ability to stimulate tumor necrosis factor alpha (TNF-α) accumulation in primary human monocytes, as well as in the human promonocytic cell line U38. In this model system, cytokine upregulation is not due to lipopolysaccharide but is mediated by a released protein. In the present study, TnphoA transposon mutagenesis was used to identify the TNF-α-inducing factor. A mutant Salmonella strain which lacks the ability to induce TNF-α was isolated from a TnphoA library. Genetic analysis of this mutant demonstrated that the hns gene has been interrupted by transposon insertion. The hns gene product is a DNA-binding protein that regulates the expression of a variety of unrelated genes in salmonellae. One of the known targets of histone-like protein H1 is flhDC, the master operon which is absolutely required for flagellar expression. Analysis of other nonflagellated mutant Salmonella strains revealed a correlation between the ability to induce TNF-α and the expression of the phase 1 filament subunit protein FliC. Complementation experiments demonstrated that FliC is sufficient to restore the ability of nonflagellated mutant Salmonella strains to upregulate TNF-α, whereas the phase 2 protein FljB appears to complement to a lesser extent. In addition, Salmonella FliC can confer the TNF-α-inducing phenotype on Escherichia coli, which otherwise lacks the activity. Furthermore, assembly of FliC into complete flagellar structures may not be required for induction of TNF-α.     

胎盘粘连植入组织和人胎盘滋养层细胞中VCAM-1的表达及其与侵入性胎盘疾病的相关性

目的探讨胎盘粘连植入组织和人胎盘滋养层细胞中血管细胞黏附分子-1(vascular cell adhesion molecule-1,VCAM-1)的表达及其与侵入性胎盘疾病的相关性。方法采用酶联免疫吸附试验检测2017年9月至2018年9月期间我院收治的20例产妇静脉血中可溶性VCAM-1(sVCAM-1)的表达水平,根据sVCAM-1的平均值将另外随机选取的200例产妇分为高表达组和低表达组,计算两组侵入性胎盘发生率。采用免疫组化染色、实时定量PCR和Western blot检测40例侵入性胎盘组织和40例正常胎盘组织中的VCAM-1、TNF-α、NF-κB p65和IκBα表达。应用20 ng/mL的TNF-α处理人胎盘滋养层HTR8/SVneo细胞系后检测细胞中VCAM-1、TNF-α、NF-κB p65和IκBα的表达。结果20例健康产妇静脉血中的VCAM-1平均水平为36.32±3.25 ng/mL。高表达组的侵入性胎盘发生率(6.98%)显著高于低表达组(0.64%)(χ^2=0.922,P=0.009)。实时定量RT-PCR和Western blot结果表明,与对照组相比,侵入性胎盘组VCAM-1的mRNA和蛋白表达水平显著升高。免疫染色显示VCAM-1蛋白主要在滋养细胞的细胞质和膜中表达,侵入性胎盘组的VCAM-1阳性率(72.50%)显著高于对照组(17.50%)(Z=-5.063,P<0.001)。与对照组相比,侵入性胎盘组的TNF-α和NF-κB p65表达水平显著升高,而IκBα表达水平显著降低(P<0.05)。与未用TNF-α处理(0 ng/mL)的HTR8/SVneo细胞相比,应用20 ng/mL浓度的TNF-α处理细胞1周后,细胞中的NF-κB p65和VCAM-1表达水平显著升高,而IκBα表达水平显著降低(P<0.05)。结论VCAM-1在侵入性胎盘产妇血液和胎盘组织中均为高表达模式。VCAM-1的活化至少部分依赖于TNF-α、NF-κB信号通路的激活,从而诱导其在滋养细胞中高表达并引起过度侵袭,导致侵入性胎盘的发生。     

人滋养层细胞侵袭力分子调节机制研究

胎盘是妊娠过程中形成的暂时性的特异器官,它在母体和胎儿间起着重要的桥梁作用。滋养层细胞具有类似于肿瘤细胞迁移和浸润的能力,作为胎盘组织的主要组成细胞之一,在胚胎植入、胎盘的形成和发育等许多生理过程中发挥着重要的作用,但同时也是多种毒素和病原微生物入侵时的靶细胞。滋养细胞侵入过度将导致绒毛膜癌等疾病的发生,浸润不足则可能造成流产、子痫前期等妊娠期疾病。目前,诸多研究表明在胎盘形成过程中,有许多分子和信号通路参与对其滋养层细胞的调控,但滋养层细胞迁移与浸润的具体机制尚不完全明确。本文对人滋养层细胞侵袭力分子调节机制进行了系统论述,旨在为研究病理性妊娠的发生、发展过程提供参考。     

Dexmedetomidine Inhibits Tumor Necrosis Factor-Alpha and Interleukin 6 in Lipopolysaccharide-Stimulated Astrocytes by Suppression of c-Jun N-Terminal Kinases

Astrocytes play an important role in immune regulation in the central nervous system (CNS). Dexmedetomidine (DEX) has been reported to exert anti-inflammatory effects on astrocytes stimulated by lipopolysaccharide (LPS) both in vitro and in vivo studies. However, the underlying molecular mechanisms remain poorly understood. This study was designed to evaluate the effects of DEX on tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6) gene expressions in LPS-challenged astrocytes. Moreover, c-Jun N-terminal kinases (JNKs) and p38 mitogen-activated protein kinase (MAPK) pathways in LPS-challenged astrocytes were also investigated. In the present study, astrocytes were stimulated with LPS in the absence and presence of various concentrations of DEX. With real-time PCR assay, we found that LPS significantly increased expressions of TNF-α and IL-6 in mRNA level; however, these effects could be attenuated by DEX. Furthermore, JNK pathway might be involved in LPS-induced astrocyte activation because JNK phosphorylation was significantly increased, and the inhibition of this pathway mediated by DEX as well as SP600125 (JNK inhibitor) decreased TNF-α and IL-6 expressions. Moreover, p38 MAPK was also activated by LPS; however, this pathway seemed to have not participated in DEX-mediated LPS-induced inflammation. These results, taken together, suggest that JNK rather than p38 MAPK signal pathway, provides the potential target for the therapeutic effects of DEX for neuronal inflammatory reactions.     

Effect of Focal Adhesion Proteins on Endothelial Cell Adhesion,Motility and Orientation Response to Cyclic Strain

Focal adhesion proteins link cell surface integrins and intracellular actin stress fibers and therefore play an important role in mechanotransduction and cell motility. When endothelial cells are subjected to cyclic mechanical strain, time-lapse imaging revealed that cells underwent significant morphological changes with their resultant long axes aligned away from the strain direction. To explore how this response is regulated by focal adhesion-associated proteins the expression levels of paxillin, focal adhesion kinase (FAK), and zyxin were knocked down using gene silencing techniques. In addition, rescue of endogenous and two mutant zyxins were used to investigate the specific role of zyxin interactions. Cells with decreased zyxin expression levels and rescue with the mutant lacking zyxin/α-actinin binding exhibited lower orientation angles after comparable times of stretching as compared to normal and control cells. However, knockdown of the expression levels of paxillin and FAK and rescue with the mutant lacking zyxin/VASP (vasodilator-stimulated phosphoprotein) binding did not significantly affect the degree of cell orientation. In addition, wound closure speed and cell–substratum adhesive strength were observed to be significantly reduced only for cells with zyxin depletion and the mutation lacking zyxin/α-actinin binding. These results suggest that zyxin and its interaction with α-actinin are important in the regulation of endothelial cell adhesive strength, motility and orientation response to mechanical stretching.     

RGD Binding to Integrin Alphavbeta3 Affects Cell Motility and Adhesion in Primary Human Breast Cancer Cultures

Integrins mediate cell adhesion to the extracellular matrix. Integrin alphavbeta3 recognizes the RGD motif as a ligand-binding site and has been associated with high malignant potential in breast cancer cells, signaling the onset of widespread metastasis. In recent years, several antagonists of integrin alphavbeta3, including RGD peptides, have been used as potential anti-cancer agents. In the present work, the effect of the linear RGD hexapeptide GRGDSP was studied, for the first time, on breast tumor explants, as well as on well-spread human breast cancer cells from primary cultures, using the explant technique, to clarify the role of this peptide in the suppression of breast cancer cell migration. The results showed that incubation of breast tumor explants with RGD peptide at the beginning of culture development inhibited completely the migration of cancer cells out of the tissue fragment as revealed by electron microscopy. RGD incubation of well-spread breast cancer cells from primary culture resulted in rounding and shrinkage of the cells accompanied by altered distribution of integrin alphavbeta3 and concomitant F-actin cytoskeletal disorganization, as revealed by immunofluorescence. Electron immunocytochemistry showed aggregation of integrin alphavbeta3 at the cell periphery and its detection in noncoated vesicles. However, Western immunoblotting showed no change in beta3 subunit expression, despite the altered distribution of the integrin alphavbeta3. In light of the above, it appears that the RGD peptide plays an important role in the modulation of cell motility and in the perturbation of cell attachment affecting the malignant potential of breast cancer cells in primary cultures.     

Increased Expression of Glutathione by Estradiol, Tumor Necrosis Factor-Alpha, and Interleukin 1-Beta in Endometrial Stromal Cells

Problem  The intracellular antioxidant system, based on glutathione (GSH), plays a key role in endometrial detoxification reactions and has been proposed to be involved in the pathogenesis endometriosis. This study was designed to evaluate whether estradiol (E₂) and proinflammatory cytokines have any effects on expression of glutathione in endometrial stromal cells (ESCs).
Method of study  Glutathione levels were measured utilizing high-performance liquid chromatography following in vitro culture and treatment of ESCs with estradiol, tumor necrosis factor-alpha (TNF-α) and interleukin 1-beta (IL-1β).
Results  The GSH level in E₂ (10⁻⁸  m ) treatment group was significantly higher than in the control group at 48 h ( P  < 0.05). In vitro treatment of ESCs with TNF-α 10 ng/mL as well as E₂ (10⁻⁸  m ) plus TNF-α 10 ng/mL for 48 hr also led to a significant increase in GSH level ( P  < 0.05; P  < 0.05, respectively). Both IL-1β 10 ng/mL and E₂ (10⁻⁸  m ) plus IL-1β 10 ng/mL for 48 hr increased GSH level significantly ( P  < 0.05; P  < 0.05, respectively) as well.
Conclusions  These findings might suggest that increased production of estradiol and proinflammatory cytokines in the peritoneal cavity possibly leads to the establishment of endometriosis through increased level of GSH.     

Dietary Fusarium Moniliforme Culture Material Induces in Vitro Tumor Necrosis Factor-Alpha Like Activity in the Sera of Swine

Sera obtained from a group of pigs (n=5) fed a diet amended with fumonisin containing Fusarium moniliforme culture material was used to determine the levels of Tumor Necrosis Factor-Alpha (TNF) activity by a functional bioassay utilizing the TNF sensitive WEHI 140 mouse fibrosarcoma cell line. Two pigs developed signs consistent with pulmonary edema which was confirmed by pathologic examination in only one pig. Significant, time dependent increases in TNF-like activity were observed in all pigs during the five days of the trial. Another group of pigs (n=5) was given a defined daily dose of the same culture material by gastric intubation. Two pigs developed fulminant pulmonary edema and sharp increases in TNF activity were observed during the 3 days of the trial in all pigs. In both cases the activity was not abrogated by addition of a neutralizing anti-human TNF monoclonal antibody suggesting that other factors may have been responsible for these effects, possibly the increased levels of sphingoid bases in the serum. Since the pig has become an important model in the study of TNF mediated endotoxic shock, these studies illustrate the relevance of certifying the absence of this important mycotoxin from corn based animal diets, specially if functional assays are used to monitor the activity of TNF in serum.