Biological action of parathyroid hormone (PTH)-related peptide (PTHrP) mediated either by the PTH/PTHrP receptor or the nucleolar translocation in chondrocytes

Parathyroid hormone (PTH)-related peptide (PTHrP) has been believed to act by binding the common receptor to PTH (PTH/PTHrP receptor). However, PTHrP is localized not only in the secretory pathway, but also in nucleoli by virtue of its nucleolar targeting signal (NTS). This review demonstrates the bipartite action of PTHrP on chondrocytes, the receptor-mediated and -independent signaling pathway. Mice with deletion of the PTHrP gene were characterized by a chondrodysplasia due to markedly reduced proliferation of epiphyseal chondrocytes. The PTH/PTHrP receptor was localized mainly in proliferative chondrocytes in the epiphyseal cartilage, indicating that PTHrP modulates normal proliferation via the receptor. In contrast to the receptor-mediated action, the mid-region of the amino acid sequence of PTHrP contains an NTS. The PTHrP-translation was found to initiate from both methionine-coding AUG and downstream leucine-coding CUGs in its signal sequence. When translated from CUGs, PTHrP accumulated in the nucleoli, and the translation from AUG localized PTHrP in both the Golgi apparatus and nucleoli. Therefore, nucleolar PTHrP appears to be derived from the translation initiating from both AUG and CUGs. A chondrocytic cell line expressing a full-length PTHrP, but not PTHrP lacking NTS, were resistant to apoptosis caused by serum depletion, suggesting that the nucleolar PTHrP in chondrocytes serves as a survival factor against apoptosis. Thus, PTHrP regulates chondrocyte proliferation, differentiation and apoptosis by mediating its receptor or acting directly on the nucleolus.     

Numb基因在培养神经干细胞中的表达

为了观察在体外培养的神经干细胞内参与细胞发育分化和细胞非对称性分裂的 notch信号传导路的分子 numb的分布和表达 ,采用无血清培养技术 ,在体外进行神经干细胞克隆的培养传代 ,经过免疫细胞化学鉴定后 ,用 num b特异性引物对培养的神经干细胞进行 RT-PCR分析 ,PCR产物经克隆测序后 ,用地高辛标记 ,对神经干细胞克隆进行原位杂交。结果表明 :在培养的神经干细胞内有大量细胞 ( >95 % )均为 numb基因表达信号阳性 ;干细胞克隆内部中心和边缘相互间未见明显差别     

同一心内神经元酪氨酸羟化酶、生长抑素的各自基因表达与贮存——原位杂交和/或免疫组织化学法光镜观察

目的　在转录与翻译水平同时证明 1 部分心内神经节的单一细胞内既出现酪氨酸羟化酶 (TH)的基因表达 ,又储存TH ;2 部分心内神经节的单一细胞内既出现生长抑素 (SS)的基因表达 ,又储存SS。　方法　在中华蟾蜍心房后壁腔静脉窦部位的冰冻切片 (30 μm)上 ,分两组以原位杂交、免疫组织化学及原位杂交 免疫组织化学结合双标方法分别进行心内神经节细胞的THmRNA、TH 免疫反应 (TH IR)及SSmRNA、SS 免疫反应 (SS IR)染色观察。　结果　在两组心内神经节切片分别发现下述标记细胞 :TH IR阳性神经元、THmRNA阳性神经元、THmRNA TH IR双阳性神经元 ;以及SS IR阳性神经元、SSmRNA阳性神经元、SSmRNA SS IR双阳性神经元。　结论　 1 证明部分心内神经节的细胞内既出现TH的基因表达 ,同时又有TH ,可能是肾上腺素能的交感神经细胞 ;2 SS系心内神经节细胞的一种内源性神经递质。本研究为心内SS能神经结构参与心功能 (兴奋传导、心肌分泌及收缩 )的局部神经调节提供直接的化学神经解剖学证据。     

大鼠纹状体边缘区内5-HT_(2A)受体的分布──原位杂交和免疫组织化学研究

已知纹状体边缘区有密集的 5 -HT纤维及终末分布。为了观察 5 -HT2 A受体 m RNA是否在大鼠纹状体边缘区表达 ,从基因分子水平和细胞水平进一步证明大鼠纹状体边缘区能否合成 5 -HT2 A受体 ,用地高辛标记的寡核苷酸探针进行原位杂交 ,研究了大鼠纹状体边缘区的 5 -HT2 A受体 m RNA的表达及分布。原位杂交结果发现 5 -HT2 A受体 m RNA阳性杂交信号在纹状体的分布不均匀 ,尾壳核只有少量中等大小的阳性胞体 ,苍白球也只有少量较大的阳性胞体 ,而在尾壳核和苍白球之间的边缘区部位则可见到许多中等大小的梭形阳性神经元胞体 ,并呈现密集的带状分布。免疫组织化学结果观察到 5 -HT受体阳性神经元胞体在纹状体的分布与原位杂交结果一致。本实验结果推测 ,大鼠纹状体边缘区神经元可以合成 5 -HT2 A受体 ,具有接受和整合 5 -HT神经递质的功能     

NGF及NGF mRNA在去部分背根猫脊髓和背根节表达的变化

用成年猫单侧备用根模型 (切断一侧 L1～ 5 、L7～ S2 节段脊髓背根 ,保留 L6 背根 ) ,用免疫组织化学和原位杂交技术 ,对脊髓背角 板层、背核和 L6 背根节中神经生长因子的表达进行了动态观察。结果证明 ,部分背根去传入后 :(1)脊髓各节段双侧背角 板层的神经生长因子和神经生长因子 m RNA阳性神经元的数量及体积显著增高、增大 ;(2 )手术侧背核神经生长因子和神经生长因子 m RNA阳性神经元的增高强于非手术侧 ,但术后两时间组的手术侧之间无差异 ;(3 )备用根背根节新出现了神经生长因子 m RNA阳性神经元 ,且神经生长因子阳性神经元数量明显高于正常组 ,且随术后时间增加而递增。以上结果表明 :部分背根去传入猫脊髓背角 板层及背核内神经生长因子水平提高 ,尤其备用根背根节神经元神经生长因子的增加 ,为备用背根传入纤维侧支生芽和突触重建提供了良好的条件 ,有助于解释脊髓初级传入纤维损伤溃变后代偿性机能恢复的机制     

CHROMOSOMAL REARRANGEMENT t(11;22) IN EXTRASKELETAL EWING'S SARCOMA AND PRIMITIVE NEUROECTODERMAL TUMOUR ANALYSED BY FLUORESCENCE IN SITU HYBRIDIZATION USING PARAFFIN-EMBEDDED TISSUE

The clonal chromosomal rearrangement t(11;22) has been reported by karyotypic analysis to be specific for Ewing's sarcoma of bone and soft tissue origin as well as primitive neuroectodermal tumour. In this report, immunohistological analysis of MIC 2 expression and fluorescence in situ hybridization (FISH) were performed using paraffin-embedded tissues. We examined t(11;22) in the nuclei isolated from two Ewing's sarcomas, four primitive neuroectodermal tumours, and three neuroblastomas, which served as negative controls by FISH with an α-satellite DNA probe for chromosome 11, a chromosome 22 marker probe, and whole chromosome painting probes for both chromosomes 11 and 22. Both cases of Ewing's sarcoma and the four primitive neuroectodermal tumour specimens were immunoreactive for MIC 2. Both Ewing's sarcomas and three of the four primitive neuroectodermal tumours contained the tumour-specific t(11;22), but the three neuroblastomas did not show this translocation. Based on the cytogenetic results and on the immunohistological investigation of MIC 2 expression, Ewing's sarcoma is suggested to be related closely to primitive neuroectodermal tumour. FISH is a useful aid in determining the tumour type of Ewing's sarcoma and putative related tumours. © 1997 by John Wiley & Sons, Ltd.     

ENPP1基因在人卵巢的定位表达及其与多囊卵巢综合征的关系

目的胰岛素抵抗及其伴随的高胰岛素血症是多囊卵巢综合征(PCOS)重要的病理生理改变,核苷酸内焦磷酸酶/磷酸二酯酶1(ENPP1)表达异常与胰岛素抵抗有关,本研究拟了解ENPP1基因在卵巢颗粒细胞中的表达及其与PCOS的关系,为进一步研究ENPP1在卵巢中的生理功能及PCOS的发病机制打下基础。方法收集PCOS患者(PCOS组)12例,以及排卵功能正常的单纯输卵管因素不育及男性不育的正常体重妇女(非PCOS组)22例患者的卵巢颗粒细胞。利用mRNA RT-PCR、原位杂交和实时荧光定量PCR的方法检测ENPP1在育龄期妇女及PCOS妇女颗粒细胞中的表达。结果RT-PCR的方法及原位杂交结果均显示,ENPP1在颗粒细胞胞浆中表达。ENPP1在PCOS组的2-ΔCt值为1.67±0.89,高于非PCOS组的2-ΔCt值0.94±0.76,两组间差异有统计学意义(P=0.017)。结论ENPP1在卵巢颗粒细胞中的表达差异提示,ENPP1参与了颗粒细胞的生理功能及卵巢中PCOS发病的病理机制。     

大鼠脊髓和后根节内5—HT1A,2A受体mRNA阳性神经元的分布

目的 观察大鼠脊髓及后根节内５－ＨＴ１Ａ,２Ａ受体ｍＲＮＡ阳性神经元的分布。方法 原位杂交组织化学技术。结果 （１）５－ＨＴ１Ａ受体ｍＲＮＡ阳性神经元分布于脊髓灰质各层,主要见于一角浅层（Ⅰ、Ⅱ层）及Ⅲ、Ⅳ层,Ⅴ、Ⅶ层和Ｘ层也有散在分布。在角（Ⅸ层）内仅有小量阳性神经元;（５）５－ＨＴ２Ａ受体ｍＲＮＡ阳性神经元的分布较局限,主要见于后角浅层及前角（Ⅸ层）神经元,在其他各层仅呈散在分布。在大鼠后根节内观察到：（１）１０．４％的后根节细胞呈５－ＨＴ１Ａ受体ｍＲＮＡ阳性,阳性细胞以中、小型节细胞为主;（２）１７．４％的后根节细胞呈５－ＨＴ２Ａ受体ｍＲＮＡ阳性,阳性细胞也以中、小型节细胞为主。结论 ５－ＨＴ１Ａ和５－ＨＴ２Ａ受体在脊髓和后根节内具有不同的分布特点,它们在介导５－羟色胺在脊髓水平的镇痛及在外周的致痛作用中