Hedgehog信号通路与骨发育

背景：Hedgehog作为骨发育中一种重要调控因子,近几年其在骨生长中作用机制的研究备受关注。 目的：介绍Hedgehog在软骨组织和骨组织发育中的作用机制及其与骨疾病的关系,从而分析Hedgehog信号通路与骨发育的研究现状及发展趋势。 方法：应用计算机检索中国期刊全文数据库和PubMed 数据库,以“Hedgehog,骨发育,间充质干细胞,软骨,成骨,骨缺陷”和“Hedgehog,bone development,mesenchymal stem cells,cartilage,osteogenesis,bone defects”为检索词。最终共纳入31篇文献进行综述。 结果与结论：Hedgehog信号与骨发育各阶段密切相关,包括间充质细胞向骨细胞分化,软骨组织和骨组织形成等各方面。其信号通路传导异常会导致各种骨畸形或骨缺陷。但是Hedgehog信号在骨发育中的详细作用机制体系尚未完善,相关动物实验技术尚未成熟,国内外尚未出现相关临床实验。由于Hedgehog即参与骨发育,又参与某些胚胎组织的血管重新形成和成年哺乳动物的血管发生,因而有望在修复骨缺损的同时解决骨组织工程血管化的问题。Hedgehog信号通路的研究在骨组织工程及临床基因干预治疗等领域有广阔的前景。     

Hedgehog signaling in development and homeostasis of the gastrointestinal tract

The Hedgehog family of secreted morphogenetic proteins acts through a complex evolutionary conserved signaling pathway to regulate patterning events during development and in the adult organism. In this review I discuss the role of Hedgehog signaling in the development, postnatal maintenance, and carcinogenesis of the gastrointestinal tract. Three mammalian hedgehog genes, sonic hedgehog (Shh), indian hedgehog (Ihh), and desert hedgehog (Dhh) have been identified. Shh and Ihh are important endodermal signals in the endodermal-mesodermal cross-talk that patterns the developing gut tube along different axes. Mutations in Shh, Ihh, and downstream signaling molecules lead to a variety of gross malformations of the murine gastrointestinal tract including esophageal atresia, tracheoesophageal fistula, annular pancreas, midgut malrotation, and duodenal and anal atresia. These congenital malformations are also found in varying constellations in humans, suggesting a possible role for defective Hedgehog signaling in these patients. In the adult, Hedgehog signaling regulates homeostasis in several endoderm-derived epithelia, for example, the stomach, intestine, and pancreas. Finally, growth of carcinomas of the proximal gastrointestinal tract such as esophageal, gastric, biliary duct, and pancreatic cancers may depend on Hedgehog signaling offering a potential avenue for novel therapy for these aggressive cancers.     

Clinical aspects of disrupted Hedgehog signaling (Review)

The Hedgehog (HH) signaling pathway is involved in patterning and development of a variety of organ systems, including the nervous system, the skeletal system, the craniofacial structures, and the gastrointestinal tract. Recent evidence also implicates this signaling pathway in the postembryonic regulation of stem-cell number in epithelia and blood. The family of HH proteins consists of at least three different members, i.e., sonic HH (SHH), Indian HH (IHH), and desert HH (DHH). SHH is the most broadly expressed member of this family and is probably responsible for the major effects of this signaling pathway. The HH signal is received and transduced via a specific receptor complex composed of patched (PTCH) and smoothened (SMOH) transmembrane proteins. Abnormalities in this signaling cascade have been found in various developmental pathologies and neoplasms such as basal cell carcinoma. The abnormalities are associated with congenital or sporadic genetic alteration affecting function of different components of the HH signaling pathway, including SHH, PTCH, SMOH and GLI proteins.     

Hedgehog信号通路抑制剂对肝内胆管癌RBE细胞生物学行为的影响

 目的: 研究Hedgehog(Hh)信号通路特异性抑制剂环杷明(cyclopamine)对人肝内胆管癌细胞株RBE生物学行为的影响。方法: 用台盼蓝染色计数法和MTT比色法检测环杷明对RBE细胞增殖的影响;流式细胞术检测凋亡率,Transwell检测环杷明处理前后RBE细胞侵袭能力的变化,Western blot检测环杷明处理前后RBE细胞中Gli1和MMP-9的蛋白表达变化。结果: 环杷明对RBE细胞株增殖的抑制作用呈剂量和时间依赖性。环杷明作用细胞24 h、48 h、72 h后,RBE细胞凋亡率逐渐升高,明显高于对照组的凋亡率。Transwell检测对照组穿透细胞数为154.52±13.61,而实验组穿透数为62.00±12.17,侵袭能力明显下降(P<0.01)。Gli1和MMP-9蛋白均在RBE细胞中表达,环杷明下调RBE细胞的Gli1和MMP-9表达。结论: 阻断Hh信号通路能抑制RBE细胞的增殖,促进其凋亡,并抑制其侵袭能力。     

类风湿关节炎患者外周血单个核细胞Sonic Hedgehog信号通路表达的初步研究

目的: 初步探讨类风湿关节炎(RA)患者外周血单个核细胞(PBMCs)和滑膜组织中Sonic Hedgehog(Shh)信号通路相关因子表达及意义。方法: 收集符合1987年美国风湿病学会(ACR)RA分类标准、28个关节疾病活动度评分(DAS28)≥3.2,病情活动RA患者(35例)及年龄、性别相匹配的健康志愿者(35例)外周血2 mL,分离PBMCs,提取总RNA,采用实时荧光定量PCR(real-time PCR)检测Shh信号通路中信号肽Shh、膜受体Ptch1和核转录因子Gli1 mRNA的表达。收集10例病情中度活动(DAS28≥3.2)RA患者的滑膜组织,同时收集5例外伤或半月板损伤(无关节炎)者滑膜组织作为对照组,免疫组化检测Shh、Ptch1和Gli1的蛋白表达情况。结果: RA患者PBMCs中Shh和Gli1 mRNA的相对表达量分别为1.36±1.48和1.15±0.68,对照组上述信号分子的mRNA表达量分别为0.47±0.25和0.49±0.05,2组差异有统计学意义(P<0.05),Ptch1 mRNA表达在2组间的差异无统计学意义(P>0.05);免疫组化示Shh和Gli1蛋白表达的阳性细胞百分率均高于对照组(P<0.05),Ptch1蛋白表达阳性细胞百分率2组无显著差异(P>0.05)。结论: RA患者PBMCs与滑膜组织中检测到Shh通路相关信号分子Shh和Gli1的表达上调,提示RA患者中可能存在Shh信号通路的激活,其在RA发病机制中的作用值得进一步研究。     

Hedgehog信号在胰腺炎症损伤中的作用机制

Hedgehog信号通路广泛参与多种器官急慢性炎症损伤、细胞再生和组织修复.尽管急性胰腺炎和慢性胰腺炎发病机制各异,在炎症损伤的同时,组织的自身修复和再生机制必然启动.国内外的研究已经证实,Hedgehog信号通路与其他信号通路发生交联反应,参与调节胰腺炎症程度、细胞再生以及纤维化,干预Hedgehog信号通路明显影响胰腺炎症进程和纤维化的程度.     

Hedgehog signaling alters adipocyte maturation of human mesenchymal stem cells

Human stem cells are powerful tools by which to investigate molecular mechanisms of cell growth and differentiation under normal and pathological conditions. Hedgehog signaling, the dysregulation of which causes several pathologies, such as congenital defects and cancer, is involved in several cell differentiation processes and interferes with adipocyte differentiation of rodent cells. The present study was aimed at investigating the effect of Hedgehog pathway modulation on adipocyte phenotype using different sources of human mesenchymal cells, such as bone marrow stromal cells and human multipotent adipose-derived stem cells. We bring evidence that Hedgehog signaling decreases during human adipocyte differentiation. Inhibition of this pathway is not sufficient to trigger adipogenesis, but activation of Hedgehog pathway alters adipocyte morphology as well as insulin sensitivity. Analysis of glycerol-3-phosphate dehydrogenase activity and expression of adipocyte marker genes indicate that activation of Hedgehog signaling by purmorphamine impairs adipogenesis. In sharp contrast to reports in rodent cells, the maturation process, but not the early steps of human mesenchymal stem cell differentiation, is affected by Hedgehog activation. Hedgehog interferes with adipocyte differentiation by targeting CCAAT enhancer-binding protein alpha and peroxisome proliferator-activated receptor (PPAR) gamma2 expression, whereas PPARgamma1 level remains unaffected. Although Hedgehog pathway stimulation does not modify the total number of adipocytes, adipogenesis appears dramatically impaired, with reduced lipid accumulation, a decrease in adipocyte-specific markers, and acquisition of an insulin-resistant phenotype. This study indicates that a decrease in Hedgehog signaling is necessary but not sufficient to trigger adipocyte differentiation and unveils a striking difference in the adipocyte differentiation process between rodent and human mesenchymal stem cells.     

Hedgehog/Gli1通路在雷奈酸锶促进骨髓间充质干细胞成骨分化过程中的作用

目的:探讨Hedgehog/Gli1信号通路在雷奈酸锶(strontium ranelate,Sr)促进骨髓间充质干细胞(BMSCs)向成骨细胞分化中的作用。方法:体外分离培养大鼠BMSCs,诱导其成骨分化,根据实验目的加入不同浓度的Sr、Hedgehog受体拮抗剂cyclopamine(Cy)及Gli1小干扰RNA(Gli1-siRNA)。用Western blotting法检测Gli1及Runx2的表达,酶标法检测碱性磷酸酶(ALP)活性,茜素红染色法检测钙结节水平。结果:应用不同浓度的Sr(0.1~5 mmol/L)处理BMSCs细胞7 d后,细胞内Gli1蛋白表达增高,Sr的浓度为3 mmol/L时,Gli1表达达到高峰;使用Cy与Sr共处理BMSCs 7 d,能拮抗Sr对Gli1蛋白表达的上调作用;应用Gli1-siRNA转染细胞后,能下调Gli1蛋白的表达,并抑制Sr对Gli1下游Runx2蛋白表达的上调作用,还可拮抗Sr对ALP活性及钙化结节形成的促进作用。结论:Hedgehog/Gli1通路参与了Sr促进骨髓间充质干细胞向成骨分化的过程。     

生物活性玻璃陶瓷涂层与Hedgehog信号通路调控成骨

BACKGROUND: Bioactive glass ceramics (BGC) has been successfully applied as titanium alloy coating in the clinic. However, the correlation between Hedgehog signaling pathway and BGC coating in osteogenesis has not yet been reported. OBJECTIVE: To explore the correlation of Hedgehog signaling pathways and BGC coating in osteogenesis. METHODS: The BGC coating was prepared and observed by scanning and transmission electron microscopes. Primary cultured rat bone marrow mesenchymal stem cells were incubated onto the BGC coating. The expressions of bone morphogenetic protein 2 and Gliloma-association oncogene homoglog in the Hedgehog signaling pathway were detected using fluorescent quantitative RT-PCR, western blot assay, and immunofluorescence staining, and the cell migration ability was observed. RESULTS AND CONCLUSION: Electron microscopes showed that there were no cracks on the smooth BGC coating that had the dense mesoporous structure, and the coating thickness was 350 nm. The mRNA and protein expressions of bone morphogenetic protein 2 and Gliloma-association oncogene homoglog in the BGC group were significantly higher than those in the control group; and the expresssed bone morphogenetic protein 2 and Gliloma-association oncogene homoglog proteins interacted with each other in the process of osteogenesis. The cell migration ability in the BGC group was obviously enhanced compared with the control group. These results indicate that the BGC coating increases the expression of Gliloma-association oncogene homoglog, then further activates the Hedgehog signaling pathway, and finally accelerates the osteoblast proliferation in combination with bone morphogenetic protein 2.     

Hedgehog regulates angiogenesis of intersegmental vessels through the VEGF signaling pathway

Background: The cellular mechanisms regulating branching and growth of the intersegmental vessels (ISVs) are not well understood. We have carried out studies demonstrating that Hedgehog (Hh) signaling is a major regulator of intersomitic vessel growth. Results: Inhibition of Hh activity by cyclopamine completely blocks formation of intersomitic vessels in the avian embryo. Examination of gene expression patterns in Hh‐deficient embryos shows that components of the VEGF and Notch signaling pathways are down‐regulated. However, we find no evidence that Notch signaling plays a significant role in regulation of intersomitic vessel growth. Indeed, it appears that Hh modulation of Vascular Endothelial Growth Factor, VEGF, is the primary regulator of growth of intersomitic vessels in the avian embryo. Conclusions: Inhibition of the VEGF pathway results in absence of ISVs, whereas stimulation of VEGF expression leads to precocious branching of ISVs. These results demonstrate that Hh is an essential modulator of VEGF expression during developmental angiogenesis. Developmental Dynamics 241:1034–1042, 2012. © 2012 Wiley Periodicals, Inc.     

Hedgehog信号传导通路在乳腺癌中表达增强

目的：研究乳腺癌细胞中,Hedgehog信号传导通路是否表现为持续的激活状态。方法：用免疫组化方法在64例乳癌标本中检测决定Hedgehog信号传导通路的组成部分,包括Shh,patched1和Gli1,SMO的表达。结果：在64例肿瘤样本中,强阳性表达Shh ,Ptch1和Glil,Smo的分别为64（100％）,61（95.3％）,62（96.9％）,和61（95.3％）,相反,各自对应相邻的正常乳腺上皮在可探测到的水平上不表达或低表达的这些蛋白,乳腺癌中的Hh通路的激活状态是普遍的,与病人的淋巴结转移无关,与癌肿的大小也无关。但与乳腺癌的特殊的病理类型可能有关。所有的64例肿瘤标本与周围正常组织相比都表现为Gli1强阳性染色,核染色Glil阳性/所有的肿瘤细胞的百分比从2%～95%不等,中位数为40.87%。Gli的核染色与雌激素受体阳性相关（P<0.05）,与孕激素受体阳性无关。结论：Hedgehog(Hh)信号传导通路可以作为潜在的乳腺癌治疗的新颖靶点。     

在乳腺癌干细胞中Hedgehog信号通路相关基因表达增强

目的 了解Hedgehog信号通路在乳腺癌发生发展中的作用.方法 用免疫磁珠法从无血清培养的乳腺癌悬浮细胞中分选CD44+CD24-细胞和非CD44+CD24-细胞,用real-time RT-PCR法检测Hedgehog信号通路主要分子$HH、PTCH1、SMO和GLI1 mRNA在细胞中的表达,用免疫组织化学法检测上述因子在乳腺癌组织中的表达.结果 分选出的CD44+CIDA-细胞约占乳腺癌悬浮细胞总数的8.25%,分选出的CD44+CD24-细胞表达干细胞标志蛋白ALDHA1和Oct-4;SHH、PTCH1、SMO和GLI1 mRNA在CD44+CD24-细胞中的表达均高于其在非CD44+CD24-细胞中的表达(P＜0.05);SMO和GLI1蛋白在三阴性乳腺癌的表达均高于非三阴性乳腺癌组织(P＜0.05).结论 在乳腺癌干细胞CD44+CD24-细胞中Hedgehog信号通路被激活,抑制癌症干细胞中Hedgehog通路的活化可能会降低或阻止乳腺癌的复发及化疗耐受.     

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 Drumstick/Lines/Bowl regulatory pathway links antagonistic Hedgehog and Wingless signaling inputs to epidermal cell differentiation

Hedgehog and Wingless signaling in the Drosophila embryonic epidermis represents one paradigm for organizer function. In patterning this epidermis, Hedgehog and Wingless act asymmetrically, and consequently otherwise equivalent cells on either side of the organizer follow distinct developmental fates. To better understand the downstream mechanisms involved, we have investigated mutations that disrupt dorsal epidermal pattern. We have previously demonstrated that the gene lines contributes to this process. Here we show that the Lines protein interacts functionally with the zinc-finger proteins Drumstick (Drm) and Bowl. Competitive protein-protein interactions between Lines and Bowl and between Drm and Lines regulate the steady-state accumulation of Bowl, the downstream effector of this pathway. Lines binds directly to Bowl and decreases Bowl abundance. Conversely, Drm allows Bowl accumulation in drm-expressing cells by inhibiting Lines. This is accomplished both by outcompeting Bowl in binding to Lines and by redistributing Lines to the cytoplasm, thereby segregating Lines away from nuclearly localized Bowl. Hedgehog and Wingless affect these functional interactions by regulating drm expression. Hedgehog promotes Bowl protein accumulation by promoting drm expression, while Wingless inhibits Bowl accumulation by repressing drm expression anterior to the source of Hedgehog production. Thus, Drm, Lines, and Bowl are components of a molecular regulatory pathway that links antagonistic and asymmetric Hedgehog and Wingless signaling inputs to epidermal cell differentiation. Finally, we show that Drm and Lines also regulate Bowl accumulation and consequent patterning in the epithelia of the foregut, hindgut, and imaginal discs. Thus, in all these developmental contexts, including the embryonic epidermis, the novel molecular regulatory pathway defined here is deployed in order to elaborate pattern across a field of cells.     

槲芪散可通过激活Hedgehog信号通路抑制大鼠肝癌前病变的形成

目的:探讨槲芪散是否通过调控Hedgehog信号通路抑制大鼠肝癌前病变的机制。方法:采用改良的Solt-Farber二步法复制大鼠肝癌前病变模型,于肝大部切除术后3 d开始给予槲芪散(8 g/kg)灌胃治疗,4周后收集血清和肝脏标本。分别采用HE染色、免疫组织化学、免疫荧光染色、Western blot、实时荧光定量PCR等方法,观察肝脏病理变化,检测肝组织谷胱甘肽S-转移酶π(glutathione S-transferase-π,GST-π)、甲胎蛋白(alpha-fetoprotein,AFP)、OV6、白蛋白(albumin,ALB)、Hedgehog信号分子Shh、Smo、Gli2及下游靶分子cyclin D、cyclin E的表达水平;利用比色法检测血清丙氨酸转氨酶(alanine aminotransferase,ALT)、天冬氨酸转氨酶(aspartate aminotransferase,AST)和γ-谷氨酰转移酶(gamma-glutamyltransferase,GGT)水平;给予Hedgehog信号通路抑制剂环杷明观察槲芪散在体外对肝卵圆细胞的影响。结果:与模型组比较,槲芪散可降低肝癌前病变大鼠血清ALT、AST和GGT水平,减轻肝癌前病变大鼠肝脏的病理变化,降低肝癌前病变标志物GST-π和AFP的表达;槲芪散可促使肝卵圆细胞标志物OV6和肝细胞标志物ALB的表达;槲芪散可激活肝脏Hedgehog信号通路,增加Shh、Smo、Gli2及其下游靶分子cyclin D、cyclin E的表达。结论:中药复方槲芪散可通过激活Hedgehog信号通路促进肝前体细胞增殖和诱导肝前体细胞向肝细胞分化,抑制肝癌前病变的形成,促进肝脏修复。     

造血干细胞自我更新的信号传导通路研究进展

造血干细胞（HSCs）自我更新受到所处微环境和自身内在基因的共同调控。相关的信号转导通路如WNT、NOTCH/JAGGED、FGF及JAK-STAT和一些重要基因家族如HOX、MYC、BMI-1等在HSCs的自我更新中起到了至关重要的作用。     

Hedgehog signaling and congenital malformations

The Hedgehog (Hh)-signaling pathway is essential for numerous developmental processes in Drosophila and vertebrate embryos. Hh signal transduction encompasses a complex series of regulatory events, including the generation of the mature Hh ligand, propagation of the ligand from source of production as well as the reception and interpretation of the signal in Hh-receiving cells. Many congenital malformations in humans are known to involve mutations in various components of the Hh-signaling pathway. This mini review summarizes some recent findings about the regulation of Hh signal transduction and describes the spectrum of human congenital malformations that are associated with aberrant Hh signaling. Based on a comparison of mouse-mutant phenotypes and human syndromes, we discuss how Hh-dependent Gli activator and repressor functions contribute to some of the congenital malformations.