Rat dentin matrix protein 3 is a compound protein of rat dentin sialoprotein and phosphophoryn

During cloning of the rat incisor phosphophoryn gene, several clones were identified with a PP antibody. One of the clones (2PP) was shown to encode a PP denoted as dentin matrix protein 2, DMP2. We have now sequenced another clone, which appears to be bifunctional, or at minimum, has two distinct domains. The 5' region encodes for dentin sialoprotein (DSP), while the 3' region encodes a small or "mini" PP. There is no stop codon between these domains. The whole gene has been named Dmp3, in keeping with the current nomenclature adopted in our laboratory. The previously reported Dmp2 gene does not encode a DSP domain but has a 114 amino acid carboxy terminal sequence identical except for a single residue with that of the DMP3. Thus, Dmp2, Dmp3 and their corresponding proteins, probably represent related members of a multigene family. There is no evidence for differential splicing. Since the DSP isolated from dentin does not carry the mini-PP domain, it must be cleaved postranslationally from DMP3.     

Novel dentin phosphoprotein frameshift mutations in dentinogenesis imperfecta type II

Lee K‐E, Kang H‐Y, Lee S‐K, Yoo S‐H, Lee J‐C, Hwang Y‐H, Nam KH, Kim J‐S, Park J‐C, Kim J‐W. Novel dentin phosphoprotein frameshift mutations in dentinogenesis imperfecta type II. The dentin sialophosphoprotein (DSPP) gene encodes the most abundant non‐collagenous protein in tooth dentin and DSPP protein is cleaved into several segments including the highly phosphorylated dentin phosphoprotein (DPP). Mutations in the DSPP gene have been solely related to non‐syndromic form of hereditary dentin defects. We recruited three Korean families with dentinogenesis imperfecta (DGI) type II and sequenced the exons and exon–intron boundaries of the DSPP gene based on the candidate gene approach. Direct sequencing of PCR products and allele‐specific cloning of the highly repetitive exon 5 revealed novel single base pair (bp) deletional mutations (c.2688delT and c.3560delG) introducing hydrophobic amino acids in the hydrophilic repeat domain of the DPP coding region. All affected members of the three families showed exceptionally rapid pulp chambers obliteration, even before tooth eruption. Individuals with the c.3560delG mutation showed only mild, yellowish tooth discoloration, in contrast to the affected individuals from two families with c.2688delT mutation. We believe that these results will help us to understand the molecular pathogenesis of DGI type II as well as the normal process of dentin biomineralization.     

Isolated dentinogenesis imperfecta and dentin dysplasia: revision of the classification

Dentinogenesis imperfecta is an autosomal dominant disease characterized by severe hypomineralization of dentin and altered dentin structure. Dentin extra cellular matrix is composed of 90% of collagen type I and 10% of non-collagenous proteins among which dentin sialoprotein (DSP), dentin glycoprotein (DGP) and dentin phosphoprotein (DPP) are crucial in dentinogenesis. These proteins are encoded by a single gene: dentin sialophosphoprotein (DSPP) and undergo several post-translational modifications such as glycosylation and phosphorylation to contribute and to control mineralization. Human mutations of this DSPP gene are responsible for three isolated dentinal diseases classified by Shield in 1973: type II and III dentinogenesis imperfecta and type II dentin dysplasia. Shield classification was based on clinical phenotypes observed in patient. Genetics results show now that these three diseases are a severity variation of the same pathology. So this review aims to revise and to propose a new classification of the isolated forms of DI to simplify diagnosis for practitioners.     

牙本质发育异常和牙本质发育不全分子遗传学的研究进展

最近,牙本质疾病的进展非常迅速。这些疾病主要分为2类,并带有不同的亚型。一类为牙本质发育异常（dentin dysplasia,DD）Ⅰ型和Ⅱ型,另一类为牙本质发育不全（dentinogenesis imperfecta,DGI）Ⅰ型、Ⅱ型和Ⅲ型。遗传连锁分析证明了DD-Ⅱ、DGI-Ⅱ和DGI-Ⅲ的关键位点位于4号染色体长臂上,这些位点包括了分泌型焦磷酸蛋白（SPP1）、骨唾液酸蛋白（BSP）、细胞外基质磷酸化糖蛋白（MEPE）、牙本质基质蛋白1（DMP1）和牙本质唾液酸焦磷酸蛋白（DSPP）基因。目前,只有DSPP的突变被证实。现将最新进展做一综述。     

Dentin phosphoprotein compound mutation in dentin sialophosphoprotein causes dentinogenesis imperfecta type III

A rare compound mutation involving a 36 bp deletion and 18 bp insertion within exon 5 of the dentin sialophosphoprotein (DSPP) gene has been identified in a family with dentinogenesis imperfecta type III (DGI-III). The DSPP gene encodes two major tooth matrix proteins dentin sialoprotein (DSP) and dentin phosphoprotein (DPP). DSPP mutations associated with DGI-III results in an in frame truncation of the serine aspartic acid triplet repeat found in DPP near the highly conserved carboxyl terminal region shortening the protein by six amino acids. Clinically this family presents with discolored amber opalescent teeth and severe attrition of the tooth structure. This study is the first report of a mutation within DPP associated with a genetic dentin disease. Our study indicates that DGI-III is allelic with some forms of DGI-II with and without progressive hearing loss and dentin dysplasia type II that have been shown to be caused by mutations within the DSP coding or signal peptide regions.     

巢蛋白在人胚胎肺中的表达

目的:研究不同时期人胚胎肺中巢蛋白的表达变化,探讨巢蛋白在肺发育过程中的作用.方法:取3～8月人胚胎肺组织,常规石蜡切片,采用免疫组织化学法检测巢蛋白在胚胎肺中的表达及分布.结果:各胎龄段(3～8月)肺均有巢蛋白的表达,巢蛋白阳性细胞主要分布于肺内支气管旁和血管中,而在支气管上皮中未发现阳性细胞.结论:正常人胚胎肺中有...     

Expression of nestin in rat and human glomerular podocytes

Nestin is a neuroepithelial precursor cell marker expressed in a variety of human cell types during development. However, no information exists on the expression of nestin in mature glomeruli as well as during the glomerular development. Here, we examined nestin expression in rat and human glomerular tissues in quiescent states using RT-PCR and immunohistochemical methods. Nestin mRNA was detected in the rat glomeruli in parallel with its expression in developing rat brains. In the normal mature rat glomeruli, WT-1 positive cells expressed nestin. Co-expression of nestin and vimentin was observed in mature rat podocytes. Immunoelectron microscopy revealed nestin localization in the cell bodies and primary processes of podocytes. A similar expression pattern was observed for vimentin. In matured glomeruli, nestin was not expressed by mesangial and endothelial cells. In the newborn rat, early developing glomeruli (metanephric cap, metanephric vesicle, comma-shaped vesicle and S-shaped body phases) expressed nestin. In the capillary loop stage, Bowman's capsules also expressed nestin. Immunoelectron microscopy demonstrated that developing podocytes and endothelial cells in S-shaped phase glomeruli expressed nestin. Additionally, in immature glomeruli, the mesangial cells in capillary stage of glomerulus also expressed nexin. As in the rat, WT-1 positive cells in human glomeruli also expressed nestin and immunoelectron microscopy confirmed nestin expression in human glomerular podocytes. These results reveal that in normal condition nestin is expressed in several glomerular cell types at early stage of development and becomes confined to podocytes in mature glomeruli, thus implicating nestin in podocyte functions.     

胰腺实性-假乳头状肿瘤内PTEN和nestin的表达

目的 探讨胰腺实体假乳头肿瘤（SPTP）细胞可能的组织学起源。方法 复习25例SPTP的临床病理特征,常规HE和超微结构观察,免疫组化EnVision法染色检测肿瘤细胞PTEN和nestin等的表达。结果 25例SPTP中女性22例,男性3例,中位年龄22．3岁。肿瘤主要位于胰腺内,1例位于后腹膜并与胰腺相连。1例伴有肝转移。肿瘤呈囊实性,出血、坏死明显。肿瘤细胞大小形态较一致,实性和假乳头状排列,部分似“室管膜样”菊形团。核卵圆形,有核沟,核仁不明显,核分裂象少见。肿瘤细胞均有PTEN阳性表达（18／18,100％）,44％（8／18）的病例有nestin的表达。超微结构观察细胞内可见酶原样分泌颗粒和神经内分泌颗粒。结论 胰腺实体假乳头肿瘤可能起源于胰腺多能干细胞。     

细胞骨架蛋白巢蛋白在人肾足细胞中的表达及意义

目的 检测细胞骨架蛋白巢蛋白在成人正常及病理状态肾组织中的表达,并观察其表达水平与患者尿蛋白的关系,初步探讨巢蛋白与足细胞损伤的关系.方法 正常对照肾组织(外科手术切除)6例,应用免疫组织化学(SP法)和免疫电镜检测巢蛋白的表达;病理状态肾组织:IgA肾病(无蛋白尿,电镜观察无足突融合,IrA-np)4例;IgA肾病(有蛋白尿,IgA-P)17例;膜性肾病8例;局灶性节段性肾小球硬化3例.应用免疫组织化学及即时RT-PCR的方法检测巢蛋白在肾组织中的表达并进行半定量、定量分析,与患者尿蛋白水平进行比较,分析两者之间相关关系.结果 巢蛋白表达在成人正常肾组织的足细胞初级足突中;免疫组织化学半定量及即时RT-PCR结果显示:IgA-np中巢蛋白的表达水平与正常肾组织差异无统计学意义;IgA-P、局灶性节段性肾小球硬化、膜性肾病中,巢蛋白的表达比正常肾组织显著降低(P<0.05),并与24 h尿蛋白呈负相关(r=-0.43,P<0.05).结论 巢蛋白在足细胞中低表达与肾小球中足细胞的损伤有关.     

Expression of nestin after renal transplantation in the rat

Chronic allograft injury (CAI) limits the long‐term success of renal transplantation. Nestin is a marker of progenitor cells, which probably contribute to its pathogenesis. We hypothesize that nestin is induced by ischemia/reperfusion injury and acute rejection, main risk factors for CAI. Syngeneic renal transplantation was performed in Lewis rats and allogeneic transplantation in the Fischer 344 to Lewis strain combination, which results in reversible acute rejection and in CAI in the long‐run. The Dark Agouti to Lewis rat strain combination was used to study fatal acute rejection. In untreated kidneys, nestin immunoreactivity was detected in glomeruli and in very few interstitial or microvascular cells. Syngeneic transplantation induced nestin expression within 4 days, which decreased until day 9 and returned to control levels on day 42. Nestin expression was strong during acute rejection and still detected during the pathogenesis of CAI on day 42. Nestin‐positive cells were identified as endothelial cells and interstitial fibroblast‐like cells co‐expressing alpha‐smooth muscle actin. A sub‐population of them expressed proliferating cell nuclear antigen. In conclusion, nestin is induced in renal grafts by ischemia/reperfusion injury and acute rejection. It is expressed by proliferating myofibroblasts and endothelial cells and probably contributes to the pathogenesis of CAI.     

Expression of bone sialoprotein and osteopontin in breast cancer bone metastases

Bone sialoprotein (BSP) and osteopontin (OPN) are prominent, mineral-associated proteins in the extracellular matrix of bone that have been implicated in the metastatic activity of cancer cells. The expression of BSP, which is normally restricted to mineralizing tissues, has been observed in cancers with a high propensity for forming bone metastases. To investigate the relationship between BSP expression and the formation of bone metastases we have conducted an initial study of the expression of BSP in 10 intraductal breast carcinoma bone metastases using immunostaining and in situ hybridization, and compared the expression with OPN. The metastases were characterized by the infiltration of tumour cells into bone with extensive bone resorption evident. Moderate to strong staining for BSP was observed in all (100%) carcinomas, which also expressed BSP mRNA as determined by in situ hybridization. Variable staining for BSP was also observed in the mineralized bone and expression of BSP mRNA could be observed in osteoblastic cells on the bone surface and in some osteocytes at sites of bone remodelling. Contrary to a previous report, BSP expression could be demonstrated by PCR in three breast cancer cell lines, MCF-7, T47-D and MDA-MB-231. Moreover, in sub-cutaneous tumours formed by MDA-MB-231 breast cancer cells injected into athymic mice, higher immunostaining for BSP was seen in large ulcerating tumours in which mineral deposits were formed. In contrast to BSP, staining for OPN in bone metastases was generally restricted to the interface between tumor cells and bone surface of the carcinomas. While OPN staining was also observed in the cytoplasm of osteoclasts, which showed strong hybridization to a digoxygenin-labelled OPN cRNA probe, expression of OPN was not clearly detectable in the tumour cells. These studies provide the first demonstration of BSP expression by tumour cells in bone metastases and support the concept that BSP may have a role in targeting metastatic cells to bone. Expression of OPN in bone metastases appears to be related to increased bone resorptive activity by osteoclasts. This revised version was published online in July 2006 with corrections to the Cover Date.     

巢蛋白及神经元素3在胚胎早期发育中的表达与分布

目的:比较巢蛋白(Nestin)与神经元素3(Ngn3)在胚胎早期发育各组织中的表达与分布.方法:采用免疫组织化学SABC法对30例5～10 周人胚胎发育中各器官组织中Nestin与Ngn3的表达与分布进行定位研究.结果:5周时,肝造血干细胞Nestin、 Ngn3阳性,胰芽原始导管上皮细胞、皮肤上皮细胞也呈Ngn3阳性反应;8周后,胚胎皮肤、椎间盘及肾上腺组织Nestin阳性,而Ngn3表达为阴性.结论: Nestin、 Ngn3在胚胎早期发育不同组织细胞的表达有不同的时空性,确切意义及机制有待进一步研究.     

Expression of nestin in ballooned neurons in patients with Creutzfeldt-Jakob disease

Nestin is an intermediate filament protein and mainly expressed during the development of the central nervous system. Recently, we reported that nestin is present in the cytoplasm, dendrites, and torpedoes of Purkinje cells in patients from Creutzfeldt-Jakob disease as the pathological change advances. In this study, we focused on the temporal and frontal lobes of the same patients in order to examine the ballooned neurons using anti-human nestin antibody. Although the ballooned neurons showed cytoplasmic immunoreactivity against nestin, the level of nestin immunoreactivity differed in each ballooned neuron. These findings could suggest that ballooned neurons are being reactivated to promote survival, although the role of nestin is not clear.     

胃肠道间质瘤中DOG1和nestin的表达及意义

目的:探讨DOG1和nestin在胃肠道间质瘤(gastrointestinal stromal tumor, GIST)中的表达及其诊断价值.方法:采用免疫组织化学EnVision法分别检测25例GIST、5例平滑肌瘤和5例神经鞘瘤中DOG1和nestin的表达.结果:DOG1和nestin在GIST中的阳性表达率分别为100%和88%,而CD117和CD34在GIST中的阳性表达率分别为84%和64%.GIST中DOG1和nestin的表达与肿瘤部位、肿瘤大小、危险度分级和组织学形态均无关(P>0.05).5例平滑肌瘤中DOG1和nestin均阴性表达,DOG1和nestin在神经鞘瘤中的阳性表达率分别为0和100%.DOG1,nestin,CD117和CD34联合检测阳性率为48%.结论:DOG1在诊断GIST中具有敏感性和特异性,而nestin则是GIST诊断中比较敏感的一种标志物,但特异性差.DOG1,nestin,CD117和CD34联合检测可提高GIST的正确诊断.     

Immunohistochemistry of extracellular matrix proteins during various stages of dentinogenesis

During dentinogenesis the expression of extracellular matrix (ECM) proteins by (pre)odontoblasts changes concomitantly with the stage of differentiation. Of these ECM proteins some are present throughout all stages of dentinogenesis, while others can only be demonstrated at particular stages of differentiation. Utilizing immunohistochemical techniques, positive detection of ECM proteins within the (pre)odontoblast or in their extracellular matrices has been demonstrated for (pro)collagen type I, III, IV, V and VI, fibronectin, tenascin, laminin, basement membrane heparan sulfate, nidogen, dentinophosphophoryns (DPP), osteocalcin (OC), osteonectin, osteopontin and 95 kDal glycoprotein. Early predentin before onset of dentin mineralization also reacts with antibodies to enamel matrix proteins. Of these ECM proteins, only DPP are exclusively synthesized by odontoblasts; DPP thus can be regarded as specific biochemical markers for odontoblast activity. A second marker for odontoblasts (but also synthesized by osteoblasts and osteocytes) is OC. In some species however OC levels in dentin seem very low. The initiation of dentin mineralization may be a matrix-mediated process in which preameloblasts also seem to be involved. Current data suggest that the DPP-collagen complex is associated with the mineralization process in dentin.     

鸡胚发育过程N-Cadherin和Neurofilament在视顶盖中的表达模式研究

目的:阐明鸡胚发育过程中神经钙黏蛋白(N-Cadherin)和神经丝蛋白(Neurofilament,NF)在视顶盖中的表达模式.方法:从鸡胚发育第6天(E6)开始到孵化的E20,分别取材、固定、包埋和冰冻切片,采用荧光免疫组织化学法检测N-Cadherin和NF蛋白在视顶盖各层的表达.结果:在鸡胚发育过程中,从E6开始,N-Cadherin和NF便呈强阳性表达,并且表现出明显各层分布的差异,E10-E14时,在NF强表达的区域与N-Cadherin重叠,E14之后NF的表达减弱,N-Cadherin无明显变化.结论:N-Cadherin和NF在鸡胚发育过程视顶盖的表达呈明显的层的分布,二者的表达既存在差异又有重叠.     

微管相关蛋白2和巢蛋白在人胚胎小肠中的表达

目的: 探讨微管相关蛋白2(MAP-2)和巢蛋白(nestin)与人胚胎小肠壁组织发育的关系。 方法: 应用免疫组织化学PV法和图像分析(NIS-DR)软件检测第2、3、4个月龄段,人胚胎小肠组织内MAP-2和nestin的表达分布规律,数据的组间比较采用单因素方差分析。 结果: 第2、3、4个月龄段,MAP-2主要表达于人胚胎小肠壁黏膜下和肌间神经丛内神经细胞和纤维,随胎龄的增大,肌间神经丛内神经细胞的阳性强度增强, 两两比较, 差异有统计学意义(P<0.05)。Nestin蛋白在小肠壁各层均有阳性表达,其黏膜下层和肌间神经丛内阳性细胞数量随胎龄增大而呈先增高再降低的趋势,两两比较, 差异有统计学意义(P<0.05)。 结论: MAP-2和nestin参与调节人胚胎小肠壁组织的生长发育过程。