纤维粘连蛋白在人滋养上皮的不同定位与功能

从正常人不同发育时期,不明原因流产,增殖型和侵蚀型葡萄胎滋养细胞角度,用免疫组织化学方法观察纤维粘连蛋白（FN）的显微定位,比较研究其不同定位与滋养上皮增殖,生长，分化,凋亡，迁移和浸润的关系。结果显示 正常人不同发育时期,FN在早孕合体滋养细胞基底膜和绒毛外滋养细胞膜呈阳性着色,在中期非合体结处的滋养细胞质呈免疫反应阳性,在足月滋养细胞呈阴性着色; 不明原因流产,FN在合体滋养细胞核内呈阳性着色; FN在增殖型葡萄胎滋养细胞膜和绒毛外滋养细胞质呈强阳性着色;FN在侵蚀型葡萄胎滋养细胞质呈阳性着色。提示FN胞质定位与滋养上皮迁移和侵蚀密切相关,FN基底膜定位与滋养细胞分化密切相关,FN胞膜定位与滋养细胞增殖相关,FN的阴性着色与滋养细胞衰老,FN胞核转位与滋养细胞凋亡可能相关。     

Neural crest regulates myogenesis through the transient activation of NOTCH

How dynamic signalling and extensive tissue rearrangements interact to generate complex patterns and shapes during embryogenesis is poorly understood. Here we characterize the signalling events taking place during early morphogenesis of chick skeletal muscles. We show that muscle progenitors present in somites require the transient activation of NOTCH signalling to undergo terminal differentiation. The NOTCH ligand Delta1 is expressed in a mosaic pattern in neural crest cells that migrate past the somites. Gain and loss of Delta1 function in neural crest modifies NOTCH signalling in somites, which results in delayed or premature myogenesis. Our results indicate that the neural crest regulates early muscle formation by a unique mechanism that relies on the migration of Delta1-expressing neural crest cells to trigger the transient activation of NOTCH signalling in selected muscle progenitors. This dynamic signalling guarantees a balanced and progressive differentiation of the muscle progenitor pool.     

Influence of PrP 106―126 on expression of laminin and fibronectin in astrocyte

Astrogliosis is a hallmark of prion disease, but the metabolic alterations of astrocytes remain poorly documented. A synthetic peptide corresponding to amino acid 106-126 of the human prion protein （PrP） has been shown to be toxic to neurons. In this study, the effects of PrP 106-126 on astrocytes were investigated in vitro. The proliferation of astrocytes was significantly （P 〈 0.05） increased when grown in media conditioned with PrP 106-126 （80 μmol/L） from microglia. The expression of laminin （LN） and fibronectin （FN） was examined at both mRNA and protein levels. The results showed that exposure of astrocytes to PrP 106-126 enhanced the expression of LN and FN. The increase of FN in astrocyte cultures required cytokines previously released by activated microglia. This study reveals the expression of LN and FN affected by PrP106-126.     

Notch signalling and the synchronization of the somite segmentation clock

In vertebrates with mutations in the Notch cell-cell communication pathway, segmentation fails: the boundaries demarcating somites, the segments of the embryonic body axis, are absent or irregular. This phenotype has prompted many investigations, but the role of Notch signalling in somitogenesis remains mysterious. Somite patterning is thought to be governed by a "clock-and-wavefront" mechanism: a biochemical oscillator (the segmentation clock) operates in the cells of the presomitic mesoderm, the immature tissue from which the somites are sequentially produced, and a wavefront of maturation sweeps back through this tissue, arresting oscillation and initiating somite differentiation. Cells arrested in different phases of their cycle express different genes, defining the spatially periodic pattern of somites and controlling the physical process of segmentation. Notch signalling, one might think, must be necessary for oscillation, or to organize subsequent events that create the somite boundaries. Here we analyse a set of zebrafish mutants and arrive at a different interpretation: the essential function of Notch signalling in somite segmentation is to keep the oscillations of neighbouring presomitic mesoderm cells synchronized.     

Collinear activation of Hoxb genes during gastrulation is linked to mesoderm cell ingression

The vertebral column exhibits segmentation and regionalization along the antero-posterior axis. During embryogenesis, the rhythmic production of the precursors of the vertebrae, the somites, imposes a segmented aspect to the spine, whereas the spine's regional differentiation is controlled by Hox genes. Here we show that in the paraxial mesoderm, Hoxb genes are first activated in a temporal collinear fashion in precursors located in the epiblast lateral to the primitive streak. Our data suggest that collinear activation of Hoxb genes regulates the flux of cells from the epiblast to the streak and thus directly controls the establishment of the genes' characteristic nested expression domains in the somites. This suggests that establishment of the spatial co-linearity in the embryo is directly controlled by the Hox genes themselves.     

RhoE/Rnd3在肝癌组织中的表达及临床意义

通过观察RhoE/Rnd3在肝癌组织中的表达情况及其与临床病理分级的关系,为探索RhoE/Rnd3的生物学功能和临床意义提供依据。对166例组织标本(其中正常肝脏组织60例,原发性肝癌病人106例)利用免疫组化研究RhoE/Rnd3在组织中蛋白水平的表达变化。RhoE/Rnd3在正常肝脏组织中普遍表达,但在原发性肝癌组织中表达低下或缺失。免疫组化结果显示RhoE/Rnd3主要分布在细胞的胞浆中。RhoE/Rnd3在原发性肝癌组织中的表达(阳性率为78%,83/106),明显低于其在正常肝组织(阳性率为97%,58/60)。P<0.005。且RhoE/Rnd3的表达随肿瘤组织分化程度的降低染色强度有下降趋势(P<0.005)。RhoE/Rnd3在原发性肝癌组织中表达明显降低,表明其对肿瘤的发生发展起到负性调控作用,结合目前的研究结果,RhoE/Rnd3可能是一种新型的抑癌基因,参与肿瘤细胞的凋亡过程。     

Molecular characterization of human reticulon 3 as a potential marker during the differentiation of human neuroblastoma SH-SY5Y cells

Neuroendocrine-specific protein (NSP) -reticulons are endoplasmic reticulum-associated protein complexes, which are localized in the endoplasmic reticulum (ER) and identified as markers for neuroendocrine differentiation. In the present study, human reticulon 3 gene (hRTN3) was cloned and its expression pattern in a variety of tissues was investigated. Truncated hRTN3s corresponding to the C-terminal (hRTN3-C) domain were expressed and purified. hRTN3 mRNA was down-regulated during the differentiation of human neuroblastoma cell line SH-SY5Y induced by all-trans-retinoic acid (RA), which suggests that, like other members of the reticulon family, hRTN3 is a potential marker for neuroendocrine differentiation.     

Regulated expression and binding of three VLA (beta 1) integrin receptors on T cells

Regulated adhesion of T cells to extracellular matrix (ECM) proteins is likely to be essential in T cell migration. Constitutive binding of various other cell types to ECM components is mediated by members of the VLA (very late antigen) subfamily of integrins. We describe here the regulated binding of resting CD4+ human T cells to ECM through three VLA integrins: VLA-4 and VLA-5 binding to fibronectin (FN), and a novel pathway of VLA-6 binding to laminin (LN). Binding to ECM is regulated in two ways. First, unlike other VLA-mediated interactions, VLA binding activity of the T cells is rapidly and dramatically augmented with cell activation without change in level of expression of the VLA molecules. Second, binding is regulated with T-cell differentiation; memory T cells express three- to four-fold more VLA-4, VLA-5, and VLA-6 than do naive cells, and bind more efficiently through them to FN and LN.     

泰山赤磷鱼酯酶同工酶(EST)的研究

运用垂直板聚丙烯酰胺凝胶电泳技术,对泰山赤磷鱼早期发育不同时期(未受精卵、受精卵、原肠晚期、色素期)和成体眼、脑、心、肌、肝、肾6种组织酯酶进行研究,结果表明(1)泰山赤磷鱼酯酶同工酶在未受精卵和早期胚胎发育时期均表达,并且酶谱和酶活性有差异,该酶的激活时序与动物胚胎发育中的细胞分化密切相关;(2)泰山赤磷鱼酯酶同工酶具有明显的组织特异性,酯酶同工酶基因表达与组织来源和细胞分化密切相关.     

Expression, distribution and function of the focal adhesion kinase (pp125FAK) during murine ectoplacental cone outgrowthin vitro

Mouse embryo implantation is a complex process that includes trophoblast cells derived from ectoplacental cone (EPC) adhesion to and migration through the extracellular matrix (ECM) of uterine endometrium and invasion into the decidua. At the time of implantation, fibronectin (FN) is abundant in the decidua and is distributed pericellularly around each individual stromal cell, and its receptor (integrin α-5β-1) expression on trophoblast populations is up-regulated. The focal adhesion kinase, a 125 ku protein tyrosine kinase (pp125 FAK), is tyrosine phosphorylated upon integrin engagement with its ECM ligand, and its tyrosine phosphorylation sites then serve as the binding sites which couple it with cellular proteins that contain Src SH2 or SH3 domains. Through these linkages, pp125 FAK may integrate multiple signals triggered by integrins. The model of EPC culture %in vitro% was used to study the expression, distribution and function of pp125 FAK during EPC outgrowth on FN. Results indicated that, pp125 FAK primarily expressed and distributed in cellular focal adhesions of the front edge of trophoblast outgrowth from EPC, and was localized in the peripheral region of the individual migrating trophblast cell; antibody or antisense oligodeoxynucleotide to pp125 FAK inhibited EPC attachment and outgrowth, as well as trophoblast cells spreading and migration. This experiment demonstrated that pp125 FAK as an integrin-mediated signaling molecule was involved in EPC outgrowth %in vitro%, and played an important role during trophoblast cells interaction with FN.     

Excitatory effect of histamine on neuronal activity of rat cerebellar fastigial nucleus in vitro

The cerebellar fastigial nucleus (FN) holds an important role in motor control and body balance. Previous studies have revealed that the nucleus is innervated by direct hypothalamocerebellar histaminergic fibers. However, the functional role of histaminergic projection in cerebellar FN has never been established. In this study, we investigated the effect of histamine on neuronal firing of cerebellar FN by using slice preparations. Sixty-five FN cells were recorded from 47 cerebellar slices, and a vast majority of the cells responded to histamine stimulation with an excitatory response (58/65, 89.2%). Perfusing slices with low-Ca2 /high-Mg2 medium did not block the histamine-induced excitation (n=10), supporting a direct postsynaptic action of histamine on the cells. Furthermore, the excitatory effect of histamine on FN neurons was not blocked by selective histamine H1 receptor antagonist triprolidine (n=15) or chlorpheniramine (n=10), but was effectively suppressed by ranitidine (n=15), a highly selective histamine H2 receptor antagonist. On the other hand, highly selective histamine H2 receptor agonist dimaprit (n=20) instead of histamine H1 receptor agonist 2-pyridylethylamine (n=16) mimicked the ex- citatory effect of histamine on FN neurons. The dimaprit-induced FN neuronal excitation was effectively antagonized by selective histamine H2 receptor antagonist ranitidine (n=13) but not influenced by se- lective histamine H1 receptor antagonist triprolidine (n=15). These results demonstrate that histamine excites cerebellar FN cells via the histamine H2 receptor mechanism and suggest that the hypotha- lamocerebellar histaminergic fibers may modulate cerebellar FN-mediated sensorimotor integration through their excitatory innervations on FN neurons.     

Appearance of new variants of membrane skeletal protein 4.1 during terminal differentiation of avian erythroid and lenticular cells

The erythrocyte plasma membrane is lined with a network of extrinsic proteins, mainly spectrin and actin, which constitute a reticulum tethered to the intrinsic anion transport protein of the lipid bilayer through a linker protein, ankyrin. Protein 4.1 forms a stable ternary complex with spectrin and actin, thereby strengthening the reticulum and anchoring it directly to the lipid bilayer or to another intrinsic protein, glycophorin. It has been found recently that spectrin, ankyrin and protein 4.1 are not erythrocyte-specific; this has elucidated further the mechanisms of plasma membrane assembly and modelling during the differentiation of diverse tissues. We have shown previously that protein 4.1 in chickens is most abundant in erythrocytes and lens cells, but is scarce or absent from other spectrin-rich cell types. In addition, it exists as a family of related polypeptides showing differential expression in these two tissues, suggesting variant-specific functions. Here we show that the pattern of protein 4.1 variants changes during the terminal differentiation of erythroid and lenticular cells, with novel variants appearing in postmitotic cells. The accumulation of these variants may lead to the final stabilization of the plasma membrane skeletons of these cells.     

Modulation of neuronal activity of cerebellar fastigial nucleus by locus coeruleus stimulation in the rat

The effects of stimulating locus coeruleus (LC) on neuronal activity of cerebellar fastigial nucleus (FN) was investigated. Stimulation of LC elicited inhibitory, excitatory and biphasic (inhibition-excitation) responses from FN cells. The majority of responsive cells showed an inhibitory response with a latency of less than 10 ms. Injection of α adrenoreceptor antagonists phentolamine (ⅳ) could block the inhibitory response of FN cells to the LC stimulation, but propranolol (ⅳ), a β adrenoreceptor antagonist, could not. These results suggest that LC-cerebellar noradrenergic afferent fibers may be involved in the cerebellar sensorimotor integration process by exerting their modulatory action on the cerebellar nuclear cells' activities.     

Cloning and expression analysis of MBLL cDNA

The mbl (muscleblind) gene of Drosophila encodes a nuclear protein which contains two Cys3His motifs. The mutation of mbl gene will disturb the differentiation of all the Drosophila's photoreceptors. Primers have been designed according to human EST086139, which is highly homologous to mbl gene. Human fetal brain cDNA library has been screened and a novel cDNA clone has been obtained. The 2595 bp cDNA, designated MBLL (muscleblind-like), contains an open reading frame which encodes 255 amino acids and has 4 Cys3His motifs (GenBank Acc. AF061261). The amino acids sequence shares high homology to Drosophila's mbl. The Northern blot and RNA dot blot hybridization of 43 human adult tissues and 7 fetal tissues show that MBLL is a widely expressed gene, but the expression amounts differ in these tissues.     

淫羊藿对RANKL、M-CSF诱导的破骨样细胞形成及FN表达的影响

建立RANKL、M-CSF诱导的破骨样细胞体外培养体系,采用细胞染色分析研究淫羊藿对RANKL和M-CSF诱导全骨髓细胞分化形成破骨样细胞的作用,并探讨FN在破骨样细胞形成过程中的作用,结果显示,淫羊藿能够抑制RANKL、M-CSF诱导的破骨样细胞的形成,FN与破骨样细胞的融合有关.