Hedgehog信号通路在消化道癌中的研究进展

<正>在肿瘤发生、发展的分子水平研究中,Wnt、Notch、mTOR、PI3K/AKT等信号通路一直是研究的重点。这些信号通路对肿瘤的生长起着重要作用,其分子机制也渐渐阐明。近年来,对Hedgehog(Hh)信号通路的研究也逐渐开展。研究发现,Hh信号通路在许多消化道肿瘤发生、发展中起着重要作用。本文总结Hh信号通路在不同消化道肿瘤发生、发展     

基于网络药理学分析右归丸治疗糖尿病性勃起功能障碍的作用机制

目的运用网络药理学方法分析右归丸治疗糖尿病性勃起功能障碍(DED)可能的分子机制。方法从TCMSP、TCMID数据库中获取右归丸的有效成分和作用靶点。在GeneCards和OMIM数据库中查询与糖尿病性勃起功能障碍相关的基因。使用基于基因本体论(GO)的功能丰富和注释工具以及京都基因和基因组百科全书(KEGG)预测这些基因的作用机制。结果以OB≥30%和DL≥0.18为活性成分筛选标准,共筛选出86个活性成分和227个靶点,从疾病数据库中筛选出与DED相关基因1061个,取两者交集,得到交集基因78个。通过Cytoscape3.7.2构建"中药活性成分-疾病靶点"网络图,共有152个节点和365条边,根据度值计算,筛选出右归丸的主要活性成分为槲皮素、山奈酚、β-谷甾醇。通过构建交集基因PPI图,根据度值计算,筛选出核心靶点为VEGFA、IL-6、CASP3、NOS3、IL-1β。通过对交集基因进行GO富集分析和KEGG富集分析发现,交集基因主要涉及抗菌反应、脂多糖反应、细菌分子反应、活性氧水平反应、第二信使介导信号转导、乙醇反应、G蛋白-偶联第二信使环核苷酸受体信号通路等生物过程;主要涉及的信号通路为神经活性配体-受体相互作用信号通路、糖尿病并发症中的晚期糖基化产物-受体信号通路、PI3K-Akt信号通路、流体剪应力与动脉粥样硬化信号通路、钙信号通路等。通过构建"基因-KEGG信号通路"图发现,主要涉及的信号通路为神经活性配体-受体相互作用信号通路、糖尿病并发症中的晚期糖基化产物-受体信号通路、PI3K-Akt信号通路。结论右归丸主要活性成分槲皮素、山奈酚、β-谷甾醇,通过核心靶点VEGFA、IL-6、CASP3、NOS3、IL-1β发挥调控神经活性配体-受体相互作用信号通路、糖尿病并发症中的晚期糖基化产物-受体信号通路、PI3K-Akt信号通路的作用,进而改善DED。我们的研究表明右归丸治疗DED的分子机制是通过中药多组分、多靶点、多途径协同作用的结果,为进一步阐明右归丸治疗DED的作用机制提供了重要的科学依据。     

胶质瘤中Hedgehog/Gli1信号通路活性变化与血管内皮生长因子表达的关系

目的 探讨胶质瘤中Hedgehog/Gli1信号通路的活化与肿瘤微血管新生之间的关系.方法 54例手术切除的胶质瘤肿瘤标本,免疫组织化学检测胶质瘤组织中Gli与肿瘤微血管密度(MVD)表达的关系;运用Western blot法及定量聚合酶链反应(PCR)检测U87、SHG44、U251及A172胶质瘤细胞中Gli1与血管内皮生长因子(VEGF)在蛋白及mRNA水平的表达;U87、SHG44中通过环巴胺(Cyclopamine)处理胶质瘤细胞束抑制Hedgehog/Gli1信号通路,观察这一信号通路活性下降后对胶质瘤中VEGF表达的影响.结果 随着Hedgehog/Gli1信号通路中Gli1表达数量的增加,MVD也相应地升高;在胶质瘤细胞株U87、SHG44、U251及A172中,U87及SHG44中Hedgehog/Gli1信号通路的活化程度较高,同时VEGF基因及蛋白的表达水平较高;通过Cyclopamine抑制这一信号通路可明显下调胶质瘤细胞中VEGF的表达,其中5μmol/L Cyclopamine组VEGF的表达分别下降至(33.3±3.3)％(U87细胞),(27.1±3.0)％(SHG44细胞);10 μmol/L组VEGF的表达分别下降至(14.7±29)％( U87),(16.3±2.4)％(SHG44).结论 部分胶质瘤中存在Hedgehog/Gli1信号通路活化,而且这一信号通路活化程度与胶质瘤的血管新生密切相关.     

Notch信号通路在骨肉瘤中的研究进展

骨肉瘤（Osteosarcoma,OS）相关信号转导通路已成为OS基因治疗研究的热点之一,其中经典的抑癌基因p53、Rbl、Wnt/β-catenin,原癌基因C-myc、erbB-2、Survivin、CTRP3等,以及血管内皮生长因子（vascularendothelialgrowthfactor,VEGF）、环氧合酶-2（cyclooxygenase-2,COX-2）等研究较为深入并已尝试应用于基因治疗。Notch作为一条重要的信号通路在OS中的研究相对较少,其作用机制尚不明确,本文就近年来Notch信号通路在OS中的研究进展作一综述。Notch基因发现于1919年,其突变可造成果蝇的残翅。随后研究发现,     

Hedgehog信号通路调控骨形成及BMSCs成骨分化的研究进展

目的综述Hedgehog信号通路对骨形成及BMSCs成骨分化的调控及其分子机制。方法查阅近年来Hedgehog通路在体内、体外及离体研究中对骨形成及BMSCs成骨分化调控的相关文献,并对其作用机制进行分析总结。结果 Hedgehog信号通路在体外研究中可通过激活下游关键分子Smoothened(Smo)及Gli1促进BMSCs成骨分化,并可通过IGF激活m TORC2-Akt信号产生类似作用;Hedgehog信号特殊结构鞭毛内运输蛋白80通过激活经典Hh-Smo-Ptch1-Gli信号、抑制非经典Hh-Gαi-Rho A应力纤维信号,调节成骨细胞的分化;应用新型Hedgehog信号激动剂Oxy133可激活Hedgehog信号。Hedgehog信号还可协同BMP及Wnt信号通路调控成骨关键分子Runx2促进细胞的成骨分化和基质矿化,并在体内研究及骨移植模型中促进骨形成及骨缺损修复愈合。结论 Hedgehog信号通路通过对自身或对其他信号及关键分子的调节对骨形成及BMSCs成骨分化进行调控,对Hedgehog信号进行靶向调控或可作为治疗某些骨相关疾病(如骨质疏松症和骨折愈合)的潜在研究方向及新靶点。     

单细胞微阵列比较基因组杂交技术在胚胎植入前遗传学筛查中的应用

目的 建立利用单细胞微阵列比较基因组杂交(array CGH,aCGH)技术进行胚胎植入前遗传学筛查(PGS)技术平台,并应用aCGH技术进行PGS获得持续妊娠. 方法 采集废弃胚胎来源卵裂球10个,核型正常男性(46,XY)淋巴细胞3个,通过单细胞全基因组扩增后,利用aCGH技术进行染色体非整倍体分析;在此基础上,将aCGH技术应用于临床一例反复流产患者. 结果 3个淋巴细胞及9个废胚来源卵裂球的全基因组扩增成功,1个废胚来源卵裂球扩增失败,扩增成功的样本通过aCGH检测后均获得明确的诊断,3个淋巴细胞分析结果与已知核型一致;临床病例5个胚胎活检的单卵裂球均得到明确诊断,移植1枚正常整倍体胚胎后获得临床持续妊娠. 结论 在胚胎植入前遗传学筛查中,单细胞aCGH技术能全面地评估胚胎染色体组情况,可应用于临床PGS.     

音猬因子信号通路与骨质疏松症关系的研究进展

骨发育的过程受到多种信号通路的调节,如Wnt、Notch、BMP、Hedgehog信号通路等。Hedgehog信号通路对骨形成的作用在过去的二十几年已经被证实。音猬因子(Ssonic hedgehog,Shh)在Hedgehog家族中表达最广泛,在该信号传导通路上对轴骨、四肢骨、颅面骨等骨骼的形成起着重要作用。骨质疏松症发病机制归根到底是成骨细胞的骨形成能力与破骨细胞的骨吸收之间的平衡被打破,并且成骨细胞的骨形成作用下降是其主要影响因素之一。本文主要从分子水平对Shh信号通路与影响骨质疏松症发生的几个主要因素进行综述,为Shh信号通路应用于骨质疏松的防治提供理论依据。     

Wnt信号通路为靶点的肿瘤治疗新进展

Wnt信号传导通路与肿瘤的关系一直都是近年来肿瘤研究的热点,Wnt信号通路包含许多信号成员蛋白,其中任何一个成员蛋白的突变或异常均可激活Wnt信号通路引起细胞异常增殖而导致肿瘤的发生。为此,针对Wnt信号通路不同基因靶点的高特异性基因药物开发以及肿瘤的分子诊断也相继出现。目前,Wnt信号通路为靶点的肿瘤基因治疗包括细胞膜水平、胞内通路成员蛋白水平、β-catenin水平和核内TCF/LEFs-β-catenin复合体水平。     

比较基因组杂交研究非综合征性唇腭裂遗传变异

目的 了解非综合征性唇腭裂(nonsyndromic cleft lip with cleft palate,NSCLP)遗传学改变的特征.方法 应用比较基因组杂交技术研究7例NSCLP患者基因组的不平衡即遗传物质的丢失或扩增情况.结果 6、7、10、13、14、16、20、22号染色体出现DNA拷贝数缺失.5、15、18、19号染色体发生DNA拷贝数扩增.出现高频率的DNA拷贝数缺失的染色体是13q(71.4%).结论 NSCLP患者的染色体均出现DNA拷贝数的变化,以DNA拷贝数的缺失为主,提示NSCLP的发生主要是其抑制基因丢失所造成的,13q极可能存在相关的NSCLP抑制基因.     

骨肉瘤相关信号转导通路研究进展

骨肉瘤是一种常见于青少年的恶性肿瘤,病死率及致残率极高.在骨肉瘤原发灶进展及转移过程中,诸多信号通路参与其中.由于骨肉瘤临床表现缺乏特异性,因此常在疾病晚期才得以确诊,近年来骨肉瘤相关信号转导通路的研究越来越受到重视,分子遗传学及细胞遗传学技术的发展为探求骨肉瘤的发病机理提供了新的研究方向.本文对相关问题进行综述.     

The role of Wnt/mTOR signaling in spinal cord injury

Spinal cord injury (SCI) is the most common disabling spinal injury, a complex pathologic process that can eventually lead to severe neurological dysfunction. The Wnt/mTOR signaling pathway is a pervasive signaling cascade that regulates a wide range of physiological processes during embryonic development, from stem cell pluripotency to cell fate. Numerous studies have reported that Wnt/mTOR signaling pathway plays an important role in neural development, synaptogenesis, neuron growth, differentiation and survival after the central nervous system (CNS) is damaged. Wnt/mTOR also plays an important role in regulating various pathophysiological processes after spinal cord injury (SCI). After SCI, Wnt/mTOR signal regulates the physiological and pathological processes of neural stem cell proliferation and differentiation, neuronal axon regeneration, neuroinflammation and pain through multiple pathways. Due to the characteristics of the Wnt signal in SCI make it a potential therapeutic target of SCI. In this paper, the characteristics of Wnt/mTOR signal, the role of Wnt/mTOR pathway on SCI and related mechanisms are reviewed, and some unsolved problems are discussed. It is hoped to provide reference value for the research field of the role of Wnt/mTOR pathway in SCI, and provide a theoretical basis for biological therapy of SCI.     

A Comprehensive Overview of Skeletal Phenotypes Associated with Alterations in Wnt/β-catenin Signaling in Humans and Mice

The Wnt signaling pathway plays key roles in differentiation and development and alterations in this signaling pathway are causally associated with numerous human diseases. While several laboratories were examining roles for Wnt signaling in skeletal development during the 1990s, interest in the pathway rose exponentially when three key papers were published in 2001–2002. One report found that loss of the Wnt co-receptor, Low-density lipoprotein related protein-5 (LRP5), was the underlying genetic cause of the syndrome Osteoporosis pseudoglioma (OPPG). OPPG is characterized by early-onset osteoporosis causing increased susceptibility to debilitating fractures. Shortly thereafter, two groups reported that individuals carrying a specific point mutation in LRP5 (G171V) develop high-bone mass. Subsequent to this, the causative mechanisms for these observations heightened the need to understand the mechanisms by which Wnt signaling controlled bone development and homeostasis and encouraged significant investment from biotechnology and pharmaceutical companies to develop methods to activate Wnt signaling to increase bone mass to treat osteoporosis and other bone disease. In this review, we will briefly summarize the cellular mechanisms underlying Wnt signaling and discuss the observations related to OPPG and the high-bone mass disorders that heightened the appreciation of the role of Wnt signaling in normal bone development and homeostasis. We will then present a comprehensive overview of the core components of the pathway with an emphasis on the phenotypes associated with mice carrying genetically engineered mutations in these genes and clinical observations that further link alterations in the pathway to changes in human bone.     

In search of the medulloblast: neural stem cells and embryonal brain tumors

Medulloblastomas have a cellular and molecular phenotype similar in many ways to that of neural stem cells. Indeed, it has long been believed that a medulloblastoma can arise from transformed neural stem cells. Recent analyses of murine transgenic lines has confirmed that cells of the external germinal layer (EGL) can be transformed into a medulloblastoma, generally in association with activation of the Hedgehog signaling pathway. Stem or progenitor cell populations outside the EGL, however, are also likely the cells of origin for a subset of medulloblastomas. Many nonnodular tumors, for example, express markers suggesting that they derive from the ventricular zone germinal layer and show evidence of Wnt pathway activation. Understanding the role of developmental signaling pathways, such as Hedgehog and Wnt, in the initiation and growth of embryonal brain tumors may lead to novel therapies for these highly malignant lesions. In addition, because such pathways are required in neural stem cells, their blockade may prove particularly effective in ablating the stem-like cells within medulloblastomas that are critical for tumor propagation. In support of this concept, inhibition of a third pathway important in stem cells, Notch, seems to deplete the stem-like tumor fraction and block formation of xenografts.     

生信分析肾阴虚型绝经后骨质疏松症分子机制及熟地黄靶向治疗

目的基于生信数据挖掘探究肾阴虚型绝经后骨质疏松症的病理机制及熟地黄的治疗靶点。方法通过GEO数据库挖掘阴虚型绝经后骨质疏松症患者差异表达基因,运用GeneCards及OMIM数据库预测骨质疏松症相关基因,采用R软件对阴虚靶点与骨质疏松靶点映射匹配。借助String数据库在线平台进行蛋白互作网络构建。分子对接预测熟地黄治疗阴虚型骨质疏松症的靶点。采用DAVID数据库进行生物过程及通路注释。结果通过分析得到差异表达基因1 272个,骨质疏松症靶点662个,阴虚型骨质疏松症相关靶点45个,主要涉及细胞凋亡调节、雌激素应答、骨骼肌系统发育等生物过程,并由PI3K-Akt、Wnt信号通路、MAPK信号通路、卵巢类固醇生成等信号通路调节。熟地2种有效成分能够作用于核心蛋白IGF1、VEGFA等。结论熟地黄可能靶向IGF1、VEGFA等核心蛋白,通过PI3K-Akt、MAPK等信号通路调节细胞凋亡及雌激素应答过程,从而实现防治阴虚型骨质疏松症的疗效。     

分子信号通路在骨质疏松症发生机制中的研究进展

目的骨质疏松症正成为影响老年人健康的老年疾病之一,主要原因是骨吸收大于骨形成,成骨细胞数量减少和活性下降。目前研究重点主要通过调节骨合成代谢的信号传导通路,抑制破骨细胞骨吸收,降低骨转换以达到减少骨量丢失。本文总结了骨代谢相关调控通路,包括MAPK信号转导途径、Notch信号通路、Wnt/-catenin信号途径、BMPs信号通路、PPAR-r信号通路、TGF-信号通路和Hedgehog信号转导途径。多个信号通路相互交叉,共同参与通路中相关因子的调节,通过激活或抑制一些关键环节的细胞因子,在骨代谢过程中发挥了主要作用。     

Glycogen synthase kinase-3 inactivation and stabilization of beta-catenin induce nephron differentiation in isolated mouse and rat kidney mesenchymes

Wnt proteins are required for induction of nephrons in mouse metanephric kidneys, but the downstream pathways that mediate tubule induction and epithelial differentiation have remained obscure. The intracellular mechanisms by which Wnt signaling mediates nephron induction in embryonic kidney mesenchymes were studied. First is shown that transient exposure of isolated kidney mesenchymes to structurally different glycogen synthase kinase-3 (GSK3) inhibitors lithium or 6-bromoindirubin-3'-oxime results in abundant epithelial differentiation and full segregation of nephrons. Shown further by mice with genetically disrupted ureteric bud or Wolffian duct development is that this nephrogenic competence arises independent of the influence of Wolffian duct-derived epithelia. Analysis of the intracellular signaling cascades downstream of GSK3 inhibition revealed stabilization of beta-catenin and upregulation of Lef1 and Tcf1, both events that are associated with the active canonical Wnt signaling. Last, genetic evidence that metanephric mesenchyme-specific stabilization of beta-catenin is sufficient to induce nephron differentiation in isolated kidney mesenchymes, similar to that induced by GSK3 inhibitors, is provided. These data show that activation of canonical Wnt pathway is sufficient to induce nephrogenesis and suggest that this pathway mediates the nephron induction in murine kidney mesenchymes.     

Targeted inhibition of T-cell factor activity promotes syndecan-2 expression and sensitization to doxorubicin in osteosarcoma cells and bone tumors in mice

Alterations of Wnt signaling appear to be involved in the pathogenesis of osteosarcoma, presenting mutations of adenomatous polyposis coli (APC) and epigenetic downregulation of Wnt inhibitory factor 1. However, the precise role of Wnt effectors in the bone cancer progression remains unclear. We previously showed that Wnt/β‐catenin/T‐cell factor (TCF) activation are responsible for the repression of syndecan‐2, a key modulator of apoptosis and chemosensitivity in osteosarcoma cells, suggesting a role of Wnt signaling in chemoresistance. In this study, we investigated the functional relationship between syndecan‐2, Wnt/β‐catenin/TCF signaling and chemosensitivity in these cells. To this goal, we selected resistant osteosarcoma cells from sensitive human cell lines using repeated exposures to doxorubicin. In doxorubicin‐responsive but not in doxorubicin‐resistant‐derived cells syndecan‐2 expression was upregulated by doxorubicin treatment. Moreover, syndecan‐2 overexpression restored the sensitivity to doxorubicin in resistant‐derived cells. We found that syndecan‐2 induction by doxorubicin is forkhead box protein O3A (Foxo3a)‐dependent. Foxo3a overexpression resulted in increased syndecan‐2 expression in sensitive and resistant‐derived cells. Doxorubicin modulated Foxo3a binding on syndecan‐2 gene promoter and induced Foxo‐dependent inhibition of Wnt/TCF activity. Conversely, β‐catenin/TCF activation impaired syndecan‐2 induction by doxorubicin, indicating that Wnt signaling is competing with the action of the cytotoxic drug. However, β‐catenin was also found to be required for Foxo3a activity. Consistently, Dickkopf 1 (DKK1) and secreted frizzled‐related protein 1 (sFRP‐1) altered doxorubicin action in sensitive cells, whereas inhibition of TCF activity strongly decreased cell viability and increased sensitivity to doxorubicin in sensitive and resistant cells. TCF inhibition also increased the effect of doxorubicin treatment in an orthotopic bone tumor model in mice. Altogether, these data provide evidence that the repression of syndecan‐2 by Wnt/β‐catenin/TCF signaling contributes to the resistance of osteosarcoma cells to doxorubicin and suggest that TCF inhibition may represent a novel therapeutic strategy in osteosarcoma. © 2012 American Society for Bone and Mineral Research.     

Where Wnts Went: The Exploding Field of Lrp5 and Lrp6 Signaling in Bone

Wnt signaling has emerged as a central regulator of skeletal modeling and remodeling. Loss‐ or gain‐of‐function mutations in two Wnt co‐receptors, Lrp5 and (more recently) Lrp6, have drawn attention to the importance of the Wnt pathway in bone biology. This review summarizes our current understanding of how the Wnt pathway operates on bone and the implications this has for skeletal physiology and drug discovery. Over the past 9 yr, rapid advances have been made in our understanding of the cellular targets for Wnt signaling and of the important regulatory molecules in this metabolic pathway. Both canonical and noncanonical signaling pathways seem to be important for mediating the effects of Wnt in bone. A rapidly expanding catalog of genetically engineered mice has been used to establish the importance of downstream effector molecules (such as β‐catenin) in the Wnt pathway, as well as the critical role of endogenous inhibitors of Wnt signaling (such as Dkk1 and sclerostin) in bone metabolism. Indeed, regulation of sclerostin in osteocytes is emerging as an important final pathway for regulating bone anabolism in response to diverse trophic stimuli, from mechnotransduction to the anabolic actions of PTH. From the outset, it had been assumed that the effects of Wnt signaling in bone were caused by direct actions in osteoblast precursors, osteoblasts, and osteocytes. However, startling recent findings have challenged this view and suggest that a key target, at least in mice, is the duodenal enterochromaffin cell. There, Wnt signaling transduced by Lrp5 regulates serotonin synthesis, which acts in an endocrine fashion to regulate bone cell metabolism. It will take time to reconcile this new information with the considerable body of information we already have regarding the actions of Wnt in bone. The Wnt pathway has rapidly emerged as a therapeutic target for drug discovery. Neutralizing antibodies and small‐molecule inhibitors of endogenous Wnt inhibitors have shown early promise as bone anabolic agents. However, given the central role of the Wnt pathway in regulating growth and development in extraskeletal tissues, as well as our still rudimentary understanding of how this signaling cascade actually affects bone metabolism, considerable work will be needed to ensure the safety of these new therapies.