The equine herpesvirus 1 EICP27 protein enhances gene expression via an interaction with TATA box-binding protein

The mechanism(s) by which the early EICP27 gene product cooperates with other equine herpesvirus 1 (EHV-1) regulatory proteins to achieve maximal promoter activity remains unknown. Transient transfection assays revealed that deletion of residues 93-140 of the 470-aa EICP27 protein substantially diminished its activation of the immediate-early (IE) promoter, whereas deletion of residues 140-470 that contain a zinc-finger motif abolished this activity. Fluorescence microscopy of cells expressing the full-length EICP27 protein or portions of this protein revealed that an arginine-rich sequence spanning residues 178-185 mediates nuclear entry. Experiments employing the mammalian Gal4 two-plasmid system revealed that the EICP27 protein does not possess an independent trans-activation domain (TAD). Protein-protein interaction assays using purified proteins revealed that residues 124-220 of the EICP27 protein mediate its direct interaction with TATA box-binding protein (TBP). Partial deletion of this TBP-binding domain attenuated the ability of the EICP27 protein to stimulate the IE and early EICP0 promoters by 68% and 71%, respectively, indicating the importance of this protein-protein interaction.     

Notch signaling pathway and Cdx2 expression in the development of Barrett's esophagus

Cdx2 expression in esophageal stem cells induced by reflux bile acids may be an important factor for development of Barrett's esophagus, whereas Notch signaling is a molecular signaling pathway that plays an important role in the determination of cell differentiation. ATOH1 (a factor associated with Notch signaling) plays an important role in differentiation of stem cells into goblet cells. However, the relationship between the Notch signaling pathway and Cdx2 expression in the development of Barrett's esophagus has not been explored. The aim of this study was to investigate the interrelationship between Notch signaling and Cdx2 in esophageal epithelial cells. The expressions of Cdx2, MUC2, and intracellular signaling molecules related to Notch signaling (Notch1, Hes1, and ATOH1) were examined using real-time polymerase chain reaction (PCR) and immunohistochemical staining with biopsy specimens obtained from esophageal intestinal metaplasia (IM) with goblet cells (IM?) and columnar epithelium not accompanied by goblet cells (IM?). For in vitro experiments, we employed human esophageal epithelial cell lines (OE33, OE19, and Het-1A). After forced Cdx2 expression by applying a Cdx2 expression vector to the cells, changes in the expressions of Notch1, Hes1, ATOH1, Cdx2, and MUC2 were analyzed by real-time PCR and western blot analysis. Changes in expressions of Notch1, Hes1, ATOH1, Cdx2, and MUC2 in cells were analyzed following stimulation with bile acids in the presence or absence of Cdx2 blocking with Cdx2-siRNA. Suppressed Hes1 and enhanced ATOH1 and MUC2 expressions were identified in IM? specimens. Forced expression of Cdx2 in cells suppressed Hes1, and enhanced ATOH1 and MUC2 expressions, whereas bile acids suppressed Hes1, and enhanced ATOH1, Cdx2, and MUC2 expressions. On the other hand, these effects were blocked by siRNA-based Cdx2 downregulation. Enhanced expression of Cdx2 by stimulation with bile acids may induce intestinal differentiation of esophageal columnar cells by interaction with the Notch signaling pathway.     

Human T cell leukemia virus type I Tax activates CD40 gene expression via the NF-kappa B pathway

The human T cell leukemia virus type I (HTLV-I) is an oncogenic retrovirus that is etiologically linked to the genesis of adult T cell leukemia (ATL) as well as HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Emerging evidence suggests that the pathogenicity of HTLV-I involves deregulated activation of immune cells, especially T lymphocytes, although the underlying mechanism remains unclear. In this study, we demonstrate that HTLV-I Tax induces the aberrant expression of CD40, a member of the tumor necrosis factor receptor (TNFR) family that plays an important role in lymphocyte activation and differentiation. In a panel of HTLV-I-transformed T cell lines analyzed, CD40 expression was highly elevated compared to HTLV-I-negative T cells. Using Tax mutants and a genetically manipulated T cell system, we demonstrated that Tax-induced CD40 expression required the NF-kappaB signaling pathway. In addition, ligation of CD40 on T cells with recombinant CD40L elicited NF-kappaB activation, suggesting that the CD40 pathway is intact and may participate in a positive regulatory loop in T cells. CD40 ligation strongly synergized with Tax to activate NF-kappaB, suggesting that CD40 signals may costimulate Tax-mediated NF-kappaB activation, particularly when Tax is expressed at low levels. Collectively, these results indicate that CD40 is a novel Tax-regulated gene, and the regulation of CD40 by Tax may play a role in cellular activation and HTLV-I-induced disease pathogenesis.     

LncRNA CCAT1通过调控MYC蛋白的表达激活MAPK信号通路影响胃癌细胞的生物学行为

目的：探讨lncRNA CCAT1通过调控瘤细胞病毒癌基因（MYC）蛋白的表达激活MAPK信号通路影响胃癌细胞的生物学行为及机制。方法：qPCR检测lncRNA CCAT1在胃癌组织和不同胃癌细胞株中的表达情况;qPCR检测MYC在胃癌组织中的表达和lncRNA CCAT1的关系,双荧光素酶报告基因检测lncRNA CCAT1和MYC之间的相互作用;流式细胞术实验检测lncRNA CCAT1对胃癌细胞的凋亡行为和细胞周期的影响;划痕愈合试验和Transwell侵袭实验检测lncRNA CCAT1对胃癌细胞的迁移和侵袭行为的变化情况;Western blot实验检测lncRNA CCAT1对MAPK通路相关蛋白表达情况的影响。结果：与正常胃组织相比,胃癌组织中lncRNA CCAT1的表达水平相对上调,与其他细胞株相比,HCG-27细胞中lncRNA CCAT1表达最高;MYC表达与相对lncRNA CCAT1的表达呈负相关关系;双荧光素酶实验证实lncRNA CCAT1能与MYC的3′UTR特异性结合,可以调控MYC的表达与活性;抑制lncRNA CCAT1的表达可以诱导G0/G1期的细胞周期停滞并促进细胞凋亡;抑制lncRNA CCAT1的表达后可以抑制胃癌细胞的迁移和侵袭能力;抑制lncRNA CCAT1后下游MAPK通路蛋白表达水平相应下调。结论：LncRNA CCAT1通过调控MYC蛋白表达激活MAPK信号通路影响胃癌细胞的生物学行为。     

Notch配体刺激白血病细胞内Cleaved Notch1蛋白及基因的表达

背景：Notch信号系统对干细胞的自身复制与分化有调节的作用。 目的：监测Notch配体刺激下白血病细胞蛋白与基因表达的变化,解析Notch信号系统在细胞内的作用。 方法：应用被Notch配体包被的培养皿,培养TMD7和THP-1细胞株,进行短期细胞增殖效果的评估。并且在刺激不同时间段后,应用免疫印迹法对Notch蛋白的活性进行检测,应用定量RT-PCR法测定各种基因表达的变化。 结果与结论：Notch配体刺激对TMD7细胞株的增殖有促进作用,对THP-1细胞株的增殖有抑制作用。配体刺激下,免疫印记结果显示2种不同相对分子质量的活性化Notch1蛋白片段。配体刺激后,各种基因的发现量的变化是不同的。而同一细胞株对3种Notch配体刺激的反应基本类似。可见Notch信号系统比现在所知道的更为复杂,可能存在着两种正向和负向的影响。     

Notch signaling regulates the phosphorylation of Akt and survival of lipopolysaccharide-activated macrophages via regulator of G protein signaling 19 (RGS19)

Macrophages play critical roles in innate immune defense by sensing microbes using pattern-recognition receptors. Lipopolysaccharide (LPS) stimulates macrophages via TLR, which leads to activation of downstream signaling cascades. In this study, we investigated the roles of a conserved signaling pathway, Notch signaling, in regulating the downstream signaling cascades of the LPS/TLR4 pathways in macrophages. Using a phospho-proteomic approach and a gamma-secretase inhibitor (GSI) to suppress the processing and activation of Notch signaling, we identified regulator of G protein signaling 19 (RGS19) as a target protein whose phosphorylation was affected by GSI treatment. RGS19 is a guanosine triphosphatase (GTPase)-activating protein that functions to negatively regulate G protein-coupled receptors via G_αi/G_αq-linked signaling. Stimulation of RAW264.7 cells with LPS increased the level of the phosphorylated form of RGS19, while LPS stimulation in the presence of GSI decreased its level. GSI treatment did not alter the mRNA level of rgs19. Treatment with GSI or silencing of rgs19 in macrophages impaired the phosphorylation of Akt Thr³⁰⁸ upon LPS stimulation. Furthermore, targeted deletion of a DNA-binding protein and binding partner of the Notch receptor, RBP-Jκ/CSL, in macrophages resulted in delayed and decreased Akt phosphorylation. Because the PI3K/Akt pathway regulates cell survival in various cell types, the cell cycle and cell death were assayed upon GSI treatment, phosphatidylinositol 3 kinase (PI3K) inhibitor treatment or silencing of rgs19. GSI treatment resulted in decreased cell populations in the G1 and S phases, while it increased the cell population of cell death. Similarly, silencing of rgs19 resulted in a decreased cell population in the G1 phase and an increased cell population in the subG1 phase. Inhibition of Akt phosphorylation by PI3K inhibitor in LPS-stimulated macrophages increased cell population in G1 phase, suggesting a possible cell cycle arrest. Taken together, these results indicate that Notch signaling positively regulates phosphorylation of Akt, possibly via phosphorylation of RGS19, and inhibition of both molecules affects the cell survival and cell cycle of macrophages upon LPS stimulation.     

干扰miR-31表达初期Notch和Hedgehog信号通路相关基因在神经干细胞中的表达变化

目的:研究干扰miR-31表达初期Notch和Hedgehog信号通路相关基因在神经干细胞(NSCs)中的表达变化。方法:利用荧光定量PCR对干扰miR-31表达初期Notch和Hedgehog信号通路相关基因在NSCs中的表达变化进行研究。结果:干扰与过表达miR-31后3 d,NSCs中的Notch信号通路相关基因Notch2的表达均增加,Jag2、Dll3和Hes1等的表达均降低;Hedgehog信号通路相关基因Wnt3的表达均增加,Bmp5与Wnt7a的表达均降低。结论:影响miR-31的表达可引发NSCs发生分化,在此过程中Notch与Hedgehog信号通路中几个基因的表达都产生相应改变,表明miR-31与NSCs分化过程相关。     

The Treponema pallidum outer membrane protein Tp92 activates endothelial cells via the chemerin/CMKLR1 pathway

Endothelium damage caused by Treponema pallidum is the key step in the systemic dissemination and pathophysiology of syphilis, particularly cardiovascular syphilis and neurosyphilis. However, the molecular mechanisms supporting endothelium damage of syphilis are undefined. The outer membrane proteins were thought to be involved. Tp92 was first identified as an outer membrane protein of T. pallidum. Homologous proteins to Tp92 play important roles in cell attachment, inflammation, and tissue destruction in other bacterial species. In this study, we investigated the effect of Tp92 on endothelial cells activation. The data showed that Tp92 induced chemerin production in activated endothelial cells. Endothelial cell-derived chemerin upregulated the expression of TNF-α and ICAM-1 in endothelial cells via CMKLR1. In addition, endothelial cell-derived chemerin promoted THP-1-derived macrophage migration towards endothelial cells. These findings suggest that Tp92 may play an important role in mediating endothelial cell activation by inducing the secretion of chemerin.     

The neutrophil-activating protein of Helicobacter pylori (HP-NAP) activates the MAPK pathway in human neutrophils

Infection by Helicobacter pylori causes an acute inflammatory response followed by a chronic infection of the human gastric mucosa characterized by the infiltration of neutrophils andmononuclear inflammatory cells. The neutrophil-activating protein of Helicobacter pylori (HP-NAP) is a virulence factor that activates neutrophils, monocytes, and mast cells. However, the mechanism by which HP-NAP activates these cells is not fully understood. Here, we show that HP-NAP induces extracellular regulated kinase (ERK) and p38-mitogen-activated protein kinase (MAPK) activation in human neutrophils; c-Jun N-terminal kinase is not activated by HP-NAP. A MAPK/ERK kinase inhibitor and a p38-MAPK inhibitor suppress HP-NAP-mediated neutrophil oxidative burst, adhesion, andchemotaxis, but not actin polymerization. Pertussis toxin (PTX) inhibits all these neutrophil functions and the MAPK activation caused by HP-NAP. These results demonstrate that HP-NAP activates neutrophils through a PTX-sensitive pathway and that ERK and p38-MAPK are involved in many neutrophil functions stimulated by HP-NAP.     

Use of the red fluorescent protein as a marker of Kaposi's sarcoma-associated herpesvirus lytic gene expression

A hallmark of all herpesvirus is the ability to exist in either a latent, or lytic, state of replication, enabling the lifelong infection of its host. Kaposi's sarcoma (KS)-associated herpesvirus (KSHV) can efficiently establish a latent infection in a variety of cell types in vitro, making it a valuable model for the study of latency and reactivation. To facilitate the identification of KSHV lytic replication, and allow subsequent experiments with live cells, a recombinant virus, rKSHV.219, was constructed using JSC-1 cells that expresses the red fluorescent protein (RFP) from the KSHV lytic PAN promoter, the green fluorescent protein (GFP) from the EF-1α promoter, and with the gene for puromycin resistance as a selectable marker. rKSHV.219 from JSC-1 cells was used to infect Vero cells for purification of the recombinant virus. Vero cells were also used for the production of rKSHV.219 at levels of 10⁵-10⁶ infectious units (IU) of virus per milliliter using a combination of KSHV/RTA expressed from a baculovirus vector, BacK50, and butyrate. Virus produced from Vero cells was used to infect human fibroblasts (HF), 293, DU145, T24, HaCaT, and HEp-2 cells, and in all cells except 293 cells, only a latent infection was established with GFP expression, but no RFP expression. In 293 cells, 10-15% of cells showed lytic gene expression. Both primary and immortalized microvascular endothelial cells (MVEC) were also infected with rKSHV.219, and reduced spontaneous lytic replication was found in immortalized cells. In all cells used in this study, rKSHV.219 efficiently established latent infections from which the virus could be reactivated to productive lytic replication. This work also demonstrated strong synergy between KSHV/RTA and butyrate for the activation of KSHV lytic replication and the production of infectious virus.     

人凋亡相关半胱氨酸肽酶4基因在川崎病中的表达及与核转录因子-κB信号通路的相关性

目的 探讨人凋亡相关半胱氨酸肽酶4基因(Caspase4,Casp4)在川崎病中的表达及与核转录因子-κB(nuclear factor-kappa B,NF-κB)信号通路的相关性.方法 收集上海市第六人民医院东院儿科2012年1月至2015年1月的15例川崎病患者血液样本然后提取单核细胞,采用mRNA定量检测血液中单核细胞Casp4及NF-κB信号通路相关因子表达情况,同时用酶联免疫吸附试验(enzyme-linked immunosorbent assay,ELISA)和免疫蛋白印迹方法检测Casp4蛋白及NF-κB信号通路相关因子表达情况,并对结果进行生物统计学的分析.结果 mRNA定量、ELISA和及免疫蛋白印迹方法结果表明川崎病患儿血液CASP4基因表达与健康对照组相比显著升高,NF-κB信号通路相关因子表达也发生变化.数据分析证明川崎病患儿血液中NF-κB p65和Casp4基因mRNA表达情况存在线性关系.结论 婴幼儿在受到环境因素和遗传因素影响后,NF-κB信号通路激活,NF-κB被释放进入细胞核内,引起Casp4基因变化,CASP4基因在川崎病中的高表达及与NF-κB信号通路相关.     

佐剂关节炎大鼠肺功能与Treg、Notch信号通路的关系

目的:观察佐剂关节炎(Adjuvant arthritis,AA)大鼠肺功能、外周血调节性T细胞(Treg)及肺组织Notch通路变化。方法:将20只SD大鼠随机分为正常对照组(NC)和模型对照组(MC),每组10只;向MC组大鼠右后足跖皮内注射弗氏完全佐剂0.1 ml致炎,复制成AA模型;致炎18天后,观察两组大鼠足跖肿胀度(E)、关节炎指数(AI)、肺功能、肺组织形态学变化,采用流式细胞术检测外周血Treg,PT-PCR法检测肺组织Notch受体及配体表达。结果:AA大鼠E、AI、1秒内平均呼气流量(FEV1/FVC%)、肺组织Notch3、Notch4及Delta1的表达明显升高;75%肺活量的最大呼气流量(FEF75)、用力最大呼气流量(PEF)、肺动态顺应性(Cldyn)降低,外周血CD4+CD25+Treg、肺组织Notch1、Jagged1、Jagged2的表达水平显著降低(P<0.01或P<0.05)。相关分析显示,肺功能参数FVC、FEF75与CD4+CD25+Treg呈正相关,FEF50、MMF与Jagged1、Notch1呈正相关;FEF25、FEF50、PEF与Delta1、Notch3、Notch4呈负相关(P<0.01或P<0.05)。结论:AA大鼠发生关节炎症同时,出现肺功能、Treg降低及Notch通路的变化;肺功能与Treg、Notch受体/配体呈高度相关性,提示Treg和Notch通路可能参与肺功能降低的过程。     

The bacteria binding glycoprotein salivary agglutinin (SAG/gp340) activates complement via the lectin pathway

Salivary agglutinin (SAG), also known as gp-340 and Deleted in Malignant Brain Tumours 1, is a glycoprotein that is present in tears, lung fluid and mucosal surfaces along the gastrointestinal tract. It is encoded by the Deleted in Malignant Brain Tumours 1 gene, a member of the Scavenger Receptor Cysteine Rich group B protein superfamily. SAG aggregates bacteria thus promoting their clearance from the oral cavity and activates the complement system. Complement proteins may enter the oral cavity in case of serum leakage, which occurs after mucosal damage. The purpose of this study was to investigate the mode of complement activation. We showed a dose-dependent C4 deposition on SAG-coated microplates showing that either the classical or lectin pathway of complement was activated. Antibodies against mannose binding lectin inhibited C4 deposition and SAG induced no C4 deposition in MBL deficient sera showing SAG activated complement through the MBL pathway. Periodate treatment of SAG abolished MBL pathway activation consistent with an involvement of SAG glycans in complement activation. This provides the first evidence for a role of SAG in complement activation through the MBL pathway and suggests a potential role of SAG as a complement activating factor at the mucosal epithelia.     

The unfolded protein response--a stress signaling pathway of the endoplasmic reticulum

The endoplasmic reticulum (ER) is a factory for folding and maturation of newly synthesized transmembrane and secretory proteins. The ER provides stringent quality control systems to ensure that only correctly folded proteins exit the ER and unfolded or misfolded proteins are retained and ultimately degraded. A number of biochemical and physiological stimuli can change ER homeostasis, impose stress to the ER, and subsequently lead to accumulation of unfolded or misfolded proteins in the ER lumen. The ER has evolved stress response signaling pathways collectively called the unfolded protein response (UPR) to cope with the accumulation of unfolded or misfolded proteins. This review summarizes our understanding of the UPR signaling developed in the recent years.     

Altered Notch ligand expression in human liver disease: further evidence for a role of the Notch signaling pathway in hepatic neovascularization and biliary ductular defects

The Jagged and Delta family of transmembrane proteins are ligands for Notch receptors, which control the proliferation and/or differentiation of many cell lineages. Expression and localization of these ligands in the adult human liver has not been fully elucidated, nor whether dysregulation of these proteins contributes to liver disease processes. We have examined expression of the five known Notch ligands in human liver. Expression of Jagged-1 and Delta-4 mRNA was seen in normal and diseased liver tissue, whereas Jagged-2, Delta-1, and Delta-3 mRNA was undetectable. In primary liver cell isolates, Jagged-1 expression was found in all cell types, whereas Delta-4 was present in biliary epithelial and liver endothelial cells, but absent in hepatocytes. Interestingly, Jagged-1 mRNA expression was significantly up-regulated in diseased liver tissue. By immunohistochemistry, Jagged-1 expression was present on most structures in normal tissue. However in disease, strikingly strong Jagged-1 immunoreactivity was observed on many small neovessels and bile ductules. The expression of downstream modulators and effectors of Notch signaling was also detectable in purified cell isolates. This, together with aberrant Jagged-1 expression suggests that the Notch signaling pathway may play a role in the neovascularization and biliary defects observed in the liver during the development of cirrhosis.