Jagged1蛋白抑制神经干细胞向神经元分化的实验

目的：研究Jagged1蛋白对神经干细胞分化的影响。方法：分离小鼠胚胎脑神经干细胞,用Jagged1蛋白、Jagged1蛋白 γ泌肽酶体外诱导神经干细胞分化,观察分化后神经元所占的比例。结果：分离的细胞能持续增殖,并能分化为神经元、星形胶质细胞和少突胶质细胞;在Jagged1蛋白的影响下,分化后神经元数量明显减少;γ泌肽酶抑制剂能阻断Jagged1蛋白的诱导作用。结论：培养的细胞为神经干细胞,并表达Notch受体;Jagged1蛋白能抑制干细胞向神经元分化,这种分化作用是通过Notch受体实现的。     

Role for notch signaling in salivary acinar cell growth and differentiation

The Notch pathway is crucial for stem/progenitor cell maintenance, growth and differentiation in a variety of tissues. The Notch signaling is essential for Drosophila salivary gland development but its role in mammalian salivary gland remains unclear. The human salivary epithelial cell line, HSG, was studied to determine the role of Notch signaling in salivary epithelial cell differentiation. HSG expressed Notch 1 to 4, and the Notch ligands Jagged 1 and 2 and Delta 1. Treatment of HSG cells with inhibitors of γ‐secretase, which is required for Notch cleavage and activation, blocked vimentin and cystatin S expression, an indicator of HSG differentiation. HSG differentiation was also associated with Notch downstream signal Hes‐1 expression, and Hes‐1 expression was inhibited by γ‐secretase inhibitors. siRNA corresponding to Notch 1 to 4 was used to show that silencing of all four Notch receptors was required to inhibit HSG differentiation. Normal human submandibular gland expressed Notch 1 to 4, Jagged 1 and 2, and Delta 1, with nuclear localization indicating Notch signaling in vivo. Hes‐1 was also expressed in the human tissue, with staining predominantly in the ductal cells. In salivary tissue from rats undergoing and recovering from ductal obstruction, we found that Notch receptors and ligands were expressed in the nucleus of the regenerating epithelial cells. Taken together, these data suggest that Notch signaling is critical for normal salivary gland cell growth and differentiation. Developmental Dynamics 238:724–731, 2009. © 2009 Wiley‐Liss, Inc.     

Effects of Delta1 and Jagged1 on early human hematopoiesis: correlation with expression of notch signaling-related genes in CD34+ cells

It has been shown that Notch signaling mediated by ligands of both Jagged and Delta families expands the hematopoietic stem cell compartment while blocking or delaying terminal myeloid differentiation. Here we show that Delta1- and Jagged1-expressing stromal cells have distinct effects on the clonogenic and differentiation capacities of human CD34(+) CD38(+) cells. Jagged1 increases the number of bipotent colony-forming unit-granulocyte macrophage (CFU-GM) and unipotent progenitors (CFU-granulocytes and CFU-macrophages), without quantitatively affecting terminal cell differentiation, whereas Delta1 reduces the number of CFU-GM and differentiated monocytic cells. Expression analysis of genes coding for Notch receptors, Notch targets, and Notch signaling modulators in supernatant CD34(+) cells arising upon contact with Jagged1 and Delta1 shows dynamic and differential gene expression profiles over time. At early time points, modest upregulation of Notch1, Notch3, and Hes1 was observed in Jagged1-CD34(+) cells, whereas those in contact with Delta1 strikingly upregulated Notch3 and Hes1. Later, myeloid progenitors with strong clonogenic potential emerging upon contact with Jagged1 upregulated Notch1 and Deltex and downregulated Notch signaling modulators, whereas T/NK progenitors originated by Delta1 strikingly upregulated Notch3 and Deltex and, to a lesser extent, Hes1, Lunatic Fringe, and Numb. Together, the data unravel previously unrecognized expression patterns of Notch signaling-related genes in CD34(+) CD38(+) cells as they develop in Jagged1- or Delta1-stromal cell environments, which appear to reflect sequential maturational stages of CD34(+) cells into distinct cell lineages.     

Notch和Wnt信号通路对神经干细胞增殖分化的影响

Notch和Wnt信号通路是调节神经干细胞(neural stem cells,NSCs)增殖、分化的重要通路,Notch信号通路的靶基因Hes1、Hes5及HES相关蛋白等分化抑制信号,通过旁侧抑制机制阻止NSCs的分化,并促进其自我更新;通过NICD与CSL DNA结合蛋白的直接结合,形成GFAP的转录激活复合物,上调GFAP的表达,从而促进NSCs向星形胶质细胞的分化。Wnt信号通过Wnt/β-catenin信号通路对细胞周期素D1和D2的转录调节,调控NSCs细胞周期的进程,使其量增殖;然而,过表达的Wnt3a和Wnt7a蛋白能够抑制NSCs的增殖,促进NSCs向神经元方向分化。     

Establishment of Dental Epithelial Cell Line (HAT-7) and the Cell Differentiation Dependent on Notch Signaling Pathway

Rat incisors grow continuously throughout life. Producing a variety of dental epithelial cells is performed by stem cells located in the cervical loop of the incisor apex. To study the mechanisms for cell differentiation, we established a dental epithelial cell line (HAT-7) originating from a cervical loop epithelium of a rat incisor. Immunochemical studies showed that HAT-7 produced the cells expressing amelogenin, ameloblastin, or alkaline phosphatase (ALP). To illustrate a role of Notch signaling in the determinant of the cell fate, we examined expression patterns of Notch1 and Jagged1 in HAT-7 density dependently. At lower cell density, Notch1- or Jagged1-expressing cells were not seen. However, when they were fully confluent, cells began to express Notch1 or Jagged1 strongly. Some ALP-positive cells were almost consistent with Notch1-expressing cells but not Jagged1-expressing cells. These results suggested that the determinant of direction of differentiation was associated with Notch signaling pathway.     

Establishment of dental epithelial cell line (HAT-7) and the cell differentiation dependent on Notch signaling pathway

Rat incisors grow continuously throughout life. Producing a variety of dental epithelial cells is performed by stem cells located in the cervical loop of the incisor apex. To study the mechanisms for cell differentiation, we established a dental epithelial cell line (HAT-7) originating from a cervical loop epithelium of a rat incisor. Immunochemical studies showed that HAT-7 produced the cells expressing amelogenin, ameloblastin, or alkaline phosphatase (ALP). To illustrate a role of Notch signaling in the determinant of the cell fate, we examined expression patterns of Notch1 and Jagged1 in HAT-7 density dependently. At lower cell density, Notch1- or Jagged1-expressing cells were not seen. However, when they were fully confluent, cells began to express Notch1 or Jagged1 strongly. Some ALP-positive cells were almost consistent with Notch1-expressing cells but not Jagged1-expressing cells. These results suggested that the determinant of direction of differentiation was associated with Notch signaling pathway.     

Notch1/Hes1信号调控C/EBPα表达对AECII细胞增殖与分化的影响

目的:探讨Notch1/Hes1信号通路能否通过调控CCAAT/增强子结合蛋白α(C/EBPα)的表达从而影响肺泡Ⅱ型上皮细胞(AECⅡ)的增殖与分化功能。方法:体外培养人AECⅡ,将细胞随机分为对照组、激活剂组(加入Notch通路激活剂Jagged1蛋白500μg/L)和抑制剂组(加入Notch通路抑制剂DAPT 10μmol/L),于干预后24 h收获各组细胞。采用RT-qPCR和Western blot法分别检测Notch1、Hes1及C/EBPα的mRNA与蛋白表达水平;CCK-8法检测细胞活力;细胞计数检测细胞增殖;流式细胞术检测细胞周期及分化。结果:与对照组相比,激活剂组Notch1、Hes1和C/EBPα的mRNA和蛋白表达显著增加(P0.05),促进AECⅡ从S期进入G_2/M期,增殖增加而分化减少(P0.05);抑制剂组Notch1、Hes1和C/EBPαmRNA和蛋白表达水平明显降低(P0.05),AECⅡ被阻滞于G_0/G_1期,增殖减少而分化增加(P0.05)。结论:Notch1/Hes1信号可调控C/EBPα表达并能影响AECⅡ增殖与分化。     

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.     

Jagged1 is the major regulator of notch‐dependent cell fate in proximal airways

Background: The Notch signaling pathway plays complex roles in developing lungs, including regulation of proximodistal fates, airway cell specification and differentiation. However, the specific Notch‐mediated signals involved in lung development remain unclear. Results: Here we report that Jagged1 is expressed in a subset of bronchial and bronchiolar epithelial cells, where it controls proximal airway cell fate and differentiation. In agreement with previous studies involving disruption of all Notch signaling, we found that deletion of Jagged1 in airway epithelium increased the number of ciliated cells at the expense of Clara cells, a phenotype associated with downregulation of Hes1. Deletion of Jagged1 also led to an increased number of pulmonary neuroendocrine cells (PNEC), suggesting that Jagged1/Notch signaling inhibits PNEC cell fate. As expected, Jagged1 deletion did not affect alveolar cell differentiation, although alveolar septation was impaired, likely an indirect effect of proximal airway defects. Finally, in the postnatal lung, Jagged1 deletion induced mucous metaplasia, accompanied by downregulation of Hes1 and Hes5. Conclusions: Our results demonstrate that Jagged1‐mediated Notch signaling regulates multiple cell fate decisions as well as differentiation in the respiratory system to coordinate lung development and to maintain a balance of airway cell types in adult life. Developmental Dynamics 242:678–686, 2013. © 2013 Wiley Periodicals, Inc.     

野百合碱诱导大鼠肺动脉高压时对肺血管壁Jagged2/Notch3信号分子表达的影响

目的:观察野百合碱诱导大鼠肺动脉高压时肺血管壁Jagged2/Notch3信号分子表达的变化,探讨Jagged2/Notch3信号在肺动脉高压发生中的作用和意义。方法:45只SD大鼠随机分为正常对照组(C组)、溶剂对照组(S组)和野百合碱模型组(M组),每组15只,通过一次性腹腔注射野百合碱50 mg/kg建立肺动脉高压模型,溶剂对照组注射相同剂量的溶媒。4周时通过HE染色观察肺血管重构,通过右心导管测定平均肺动脉压(m PAP)和右心室收缩压(RVSP)。采用免疫组化和实时荧光定量PCR等方法检测肺血管壁Jagged2/Notch3/Hes5蛋白和mRNA表达的变化。结果:与正常对照和溶剂对照组相比,4周时野百合碱模型组的血管壁显著增厚,中膜厚度百分比增加(P0.01);此外野百合碱模型组的m PAP和RVSP显著高于正常对照和溶剂对照组(P0.01);免疫组化和实时荧光定量PCR结果提示Jagged2主要表达于肺小动脉内膜,Notch3、Hes5主要表达于肺小动脉中层平滑肌,与溶剂对照组以及正常对照组相比,野百合碱模型组肺小动脉的Jagged2、Notch3和Hes5表达显著增高。结论:Jagged2/Notch3信号分子的激活可能在野百合碱诱导肺动脉高压发生中起重要作用。     

Notch3 and Jagged2 contribute to gastric cancer development and to glandular differentiation associated with MUC2 and MUC5AC expression

Kang H, An H‐J, Song J‐Y, Kim T‐H, Heo J‐H, Ahn D‐H & Kim G
(2012) Histopathology  61, 576–586 Notch3 and Jagged2 contribute to gastric cancer development and to glandular differentiation associated with MUC2 and MUC5AC expression Aims: Notch signalling plays diverse roles in malignant tumours as well as in normal tissue development. In this study we investigated the expression of Notch signalling pathway genes and their clinicopathological significance in gastric carcinomas. Methods and results: Notch1, Notch3, Jagged1, Jagged2 and Hes1 expression were analysed by quantitative real‐time polymerase chain reaction (qRT–PCR) (n = 81) and immunohistochemistry (n = 103) in gastric carcinomas. MUC2 and MUC5AC expression were also assessed, using immunohistochemistry only. With qRT–PCR, Notch1, Notch3, Jagged1 and Jagged2 expression were increased significantly in tumour compared to normal tissue (P < 0.001, P = 0.002, P = 0.008 and P < 0.001, respectively). Overexpression of Notch3 and Jagged2 was associated with intestinal‐type carcinomas (P = 0.024) and better histological differentiation (P = 0.047), respectively. Immunohistochemistry showed a reverse correlation between MUC2 and Notch3 or Jagged1 (P = 0.033 and P = 0.005, respectively) and between MUC5AC and Jagged1 or Hes1 (P = 0.004 and P = 0.002, respectively). Notch3 and Jagged2 gene overexpression related to a favourable outcome on univariate (P = 0.046 and P = 0.042, respectively) and multivariate (P = 0.045, Notch3) analysis. Conclusions: The expression of Notch3 and Jagged2 is associated not only with gastric cancer development but also with the intestinal/glandular differentiation of gastric carcinoma cells, suggesting a role as a possible favourable prognostic indicator.     

Expression pattern of notch1, 2 and 3 and Jagged1 and 2 in lymphoid and stromal thymus components: distinct ligand-receptor interactions in intrathymic T cell development.

The suggested role of Notch1 or its mutants in thymocyte differentiation and T cell tumorigenesis raises the question of how the different members of the Notch family influence distinct steps in T cell development and the role played by Notch ligands in the thymus. We report here that different Notch receptor-ligand partnerships may occur inside the thymus, as we observed differential expression of Notch1, 2 and 3 receptors, their ligands Jagged1 and 2, and downstream intracellular effectors hairy and Enhancer of Split homolog 1 (HES-1) and hairy and Enhancer of Split homolog 5 (HES-5), depending on ontogenetic stage and thymic cell populations. Indeed, while Jagged2 is expressed in both stromal cells and thymocytes, Jagged1 expression is restricted to stromal cells. Moreover, a differential distribution of Notch3, with respect to Notch1, was observed in distinct age-related thymocyte subsets. Finally, Notch3 was preferentially up-regulated in thymocytes, following the induction of their differentiation by interaction with thymic epithelial cells expressing the cognate Jagged1 and 2 ligands, suggesting that, besides Notch1, Notch3 may also be involved in distinct steps of thymocyte development. Our results suggest that the Notch signaling pathway is involved in a complex interplay of T cell developmental stages, as a consequence of the heterogeneity and specific expression of members of the Notch receptor family and their cognate ligands, in distinct thymic cell compartments.     

Notch信号通路在骨髓间充质干细胞向肝细胞分化过程中的动态表达特征

目的　探寻Notch信号通路对BM-MSCs向肝细胞分化的影响机制。 方法　诱导BM-MSCs分化成肝细胞。当BM-MSCs分化至第0、7、11、21天时,反向斑点杂交实验检测Notch信号通路中的关键基因的mRNA表达水平。建立加入Jagged1上调信号通路的对照组RT-PCR技术绘制出BM-MSCs分化状态分子表达谱与正常情况下对比。 结果　BM-MSCs分化进行至第21天,反向斑点杂交检测到的关键基因的mRNA表达水平低于第0、7、11天。加入Jagged1后Notch信号通路被激活,导致下游基因Hes1 和 Hey1的被表达。BM-MSCs分化过程中Albumin未被检测到。 结论　本研究的结果表明Notch信号通路在BMMSCs分化成肝细胞过程进行调控是必需的,但是分化必须在信号通路下调的情况下才能进行下去。     

阿司匹林与尼莫地平预处理可改善脑缺血再灌注损伤

目的 探讨阿司匹林与尼莫地平预处理对脑缺血再灌注预后的影响。方法 80只健康雄性SD大鼠随机分为假手术组、模型组、阿司匹林预处理组以及阿司匹林+尼莫地平预处理组,每组20只。以线栓法建立大鼠脑缺血再灌注模型,各组大鼠均于模型制作前5 d开始灌胃给药,连续用药5 d。假手术组和模型组给予生理盐水;阿司匹林预处理组灌胃给予阿司匹林50 mg/kg;阿司匹林+尼莫地平预处理组灌胃给予阿司匹林50 mg/kg+尼莫地平10 mg/kg。缺血2 h及再灌注24 h后比较各组神经功能缺失评分,用TTC染色测定脑梗死体积,用ELISA法测定脑组织中超氧化物歧化酶(SOD)、丙二醛(MDA)、血栓素B2和6-酮-前列腺素1α的含量,并通过Real-time PCR检测大鼠Notch1、Jagged1和Hes1 mRNA表达以及通过Western blotting 检测Notch信号通路中Notch1、Jagged1及下游物质Hes1的表达水平。结果 与模型组相比,阿司匹林+尼莫地平预处理组神经功能缺损评分显著降低（P<0.05）,脑梗死体积显著缩小;阿司匹林预处理组和阿司匹林+尼莫地平预处理组脑组织SOD及6-酮-前列腺素1α显著高于模型组,MDA、血栓素B2及血栓素B2/6-酮-前列腺素1表达均低于模型组,且阿司匹林+尼莫地平预处理组变化更明显(P<0.05);阿司匹林预处理组和阿司匹林+尼莫地平预处理组的Notch1、Jagged1和Hes1 mRNA及蛋白表达水平显著低于模型组（P<0.05）,且阿司匹林+尼莫地平预处理组表达量低于阿司匹林预处理组（P<0.05）。结论 阿司匹林与尼莫地平两药合用时明显优于阿司匹林单独给药,可显著改善大鼠脑缺血再灌注损伤,这可能是通过影响Notch信号通路达到脑组织保护的作用。     

Blockade of the Notch1/Jagged1 pathway in Kupffer cells aggravates ischemia-reperfusion injury of orthotopic liver transplantation in mice

Abstract

Liver ischemia-reperfusion injury (IRI) represents a risk factor for early graft dysfunction and an obstacle to expanding donor pool in orthotopic liver transplantation (OLT). Kupffer cells (KCs) are the largest antigen-presenting cell (APC) group and the primary modulators of inflammation in liver tissues. The vital role of Notch1/Jagged1 pathway in mouse OLT model has been reported, however, its potential therapeutic mechanism is unknown. Here, we made use of short hairpin RNA-Jagged1 and AAV-Jagged1 to explore the effects of Notch1/Jagged1 pathway in OLT. In vitro, blockade of Notch1/Jagged1 pathway downregulated the expression of Hairy and enhancer of split-1 (Hes1) gene, which in turn increased the proinflammatory effects of KCs. Moreover, the anti-inflammatory effects of Notch1/Jagged1 pathway were induced by inhibiting Hes1/gene of phosphate and tension/protein kinase B/Toll-like receptor 4/nuclear factor kappa B (Hes1/PTEN/AKT/TLR4/NF-κB) axis in KCs. In vivo, we used a well-established mouse model of OLT to mimic clinical transplantation. Mice were stochastically divided into 6 groups: Sham group (n?=?15); Normal saline (NS) group (n?=?15); Adeno-associated virus–green fluorescent protein (AAV-GFP) group (n?=?15); AAV-Jagged1 group (n?=?15); Clodronate liposome (CL) group (n = 15); CL+AAV-Jagged1 group (n = 15) . After OLT the liver damage in AAV-Jagged1 group were significantly accentuated compared to the AAV-GFP group. While blockade of Jagged1 aftet clearence of KCs by CL would not lead to further liver injuries. Taken together, our study demonstrated that blockade of Notch1/Jagged1 pathway aggravates inflammation induced by lipopolysaccharide (LPS) via Hes1/PTEN/AKT/TLR4/NF-κB in KCs, and the blockade of Notch1/Jagged1 pathway in donor liver increased neutrophil/macrophage infiltration and hepatocellular apoptosis, which suggested the function of Notch1/Jagged1 pathway in mouse OLT and highlighted the protective function of Notch1/Jagged1 pathway in liver transplantation.     

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。