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Differentiation and proliferation of pulmonary neuroendocrine cells

PROGRESS IN HISTOCHEMISTRY AND CYTOCHEMISTRY 1999年第4期34卷 253-+页

作者： Ito, T Yokohama City Univ Sch Med Dept Pathol Kanazawa Ku Yokohama Kanagawa 2360004 Japan

In this review article the morphological profiles of pulmonary neuroendocrine cells (PNEC) in experimental animals and humans are described. Although the mechanisms of differentiation and proliferation of neuroendocrine cells in the airway epithelium remain to be solved, several experimental studies using explant culture and cell culture systems of fetal animal lungs have been performed to clarify fundamental phenomena associated with neuroendocrine differentiation and proliferation. Experimental animal studies using chronic hypoxia, toxic substances and carcinogens have succeeded in inducing alterations in PNEC systems, and these studies have elucidated the reactions of PNEC in cell injury and inflammation, and functional aspects of PNEC in disease conditions. Human pulmonary neuroendocrine tumors include various histological subtypes, and show divergent morphological and biological varieties. Molecular abnormalities of small cell carcinoma, the most aggressive subtype of pulmonary neuroendocrine tumors, have been extensively studied, but the mechanism of neuroendocrine differentiation of this tumor is still largely unknown. PNEC share common phenotypes with neuronal cells, and developmental studies have begun contributed evidence that similar transcriptional networks, including active and repressive basic helix-loop-helix (bHLH) factors, function in the differentiation of both PNEC and neuronal cells. Such a bHLH network may also play a central role in determining cell differentiation in lung carcinomas. Further studies of the neuronal bHLH network, its regulatory system and related signal transduction pathways, will be required for understanding the mechanisms of neuroendocrine differentiation and proliferation in normal and pathological lung conditions.

关键词：细胞分化细胞分裂肺/细胞学神经分泌系统/细胞学动物人类

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Monte Carlo simulation of 3-D buffered Ca²⁺ neuroendocrine cells

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BIOPHYSICAL JOURNAL 2000年第1期78卷 13-33页

作者： Gil, A Segura, J Pertusa, JAG Soria, B Univ Miguel Hernandez Dept Ciencias Expt & Tecnol Edificio La Galia Inst Bioingn Alicante 03202 Spain

Buffered Ca2+ diffusion in the cytosol of neuroendocrine cells is a plausible explanation for the slowness and latency in the secretion of hormones. We have developed a Monte Carlo simulation to treat the problem of 3-D diffusion and kinetic reactions of ions and buffers. The 3-D diffusion is modeled as a random walk process that follows the path of each ion and buffer molecule, combined locally with a stochastic treatment of the first-order kinetic reactions involved. Such modeling is able to predict [Ca2+] and buffer concentration time courses regardless of how low the calcium influx is, and it is therefore a convenient method for dealing with physiological calcium currents and concentrations. We study the effects of the diffusional and kinetic parameters of the model on the concentration time courses as well as on the local equilibrium of buffers with calcium. An in-mobile and fast endogenous buffer as described by Klingauf and Neher (1997, Biophys. J. 72:674-690) was able to reach local equilibrium with calcium;however, the exogenous buffers considered are displaced drastically from equilibrium at the start of the calcium pulse, particularly below the pores. The versatility of the method also allows the effect of different arrangements of calcium channels on submembrane gradients to be studied, including random distribution of calcium channels and channel clusters. The simulation shows how the particular distribution of channels or clusters can be of relevance for secretion in the case where the distribution of release granules is correlated with the channels or clusters.

关键词：钙/代谢钙通道/生理学扩散动力学模型生物学蒙特卡罗法神经分泌系统/细胞学神经分泌系统/生理学结果可重复性软件动物

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Neurosecretory cells without neurosecretion: evidence of an independently regulated trait of the cell phenotype

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JOURNAL OF PHYSIOLOGY-LONDON 1999年第1期520卷 43-52页

作者： Malosio, ML Benfante, R Racchetti, G Borgonovo, B Rosa, P Meldolesi, J San Raffaele Sci Inst DIBIT Dept Neurosci I-20132 Milan Italy Univ Milan B Ceccarelli Neurobiol Ctr Dept Pharmacol I-20132 Milan Italy CNR Cellular & Mol Pharmacol Ctr Dept Med Pharmacol I-20129 Milan Italy

Neurosecretion competence is a fundamental property that enables differentiated neurones and professional neurosecretory cells to store neurotransmitters and hormones in specialized organelles, the synaptic-like vesicles and dense granules, and to release them by regulated exocytosis. In our laboratory the study of rat phaeochromocytoma (PC12) clones that fail to express the above organelles or any other components involved in neurosecretion, whilst maintaining most of the general markers of the parental population, has served to demonstrate that this trait is controlled independently from the rest of the phenotype. The present review focuses on recent advances in elucidating the molecular mechanisms governing neurosecretion competence. Moreover, the opportunities that such neurosecretion-defective PC12 clones offer for the investigation of new aspects of regulated exocytosis and the localization of its components are summarized.

关键词：神经分泌/遗传学神经分泌/生理学神经分泌系统/细胞学神经分泌系统/生理学 PC12细胞表型动物大鼠

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L to D amino acid isomerization in a peptide hormone is a late post-translational event occurring in specialized neurosecretory cells

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JOURNAL OF BIOLOGICAL CHEMISTRY 2000年第48期275卷 37870-37875页

作者： Soyez, D Toullec, JY Ollivaux, C Géraud, G Univ Paris 06 Ecole Normale Super CNRS EP2028 Lab Signaux Endocrines & Toxines Invertebres F-75005 Paris France Univ Paris 06 Inst Jacques Monod Serv Imagerie CNRS F-75251 Paris 05 France Univ Paris 07 F-75251 Paris 05 France

Modification of the chirality of a single amino acid residue within a peptide chain appears to be novel additional mechanism leading to structural and functional diversification of eukaryotic bioactive peptides. This phenomenon has been studied at the cellular level in a neuroendocrine organ which elaborates a mixture of diastereoisomers of a 72-residue neuropeptide, crustacean hyperglycemic hormone. For the first time, amino acid isomerization has been shown to occur in the perikarya of fully specialized neurosecretory cells, as a late step of the maturation of the hyperglycemic hormone precursor and after propeptide cleavage. The specificity and efficiency of this phenomenon indicates the existence of a new enzyme family involved in the biogenesis of peptide hormones.

关键词：氨基酸序列河虾科异构现象神经组织蛋白质类/化学神经组织蛋白质类/代谢神经分泌系统/细胞学蛋白质加工转译后动物女(雌)性男(雄)性

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Acute osmotic/stress stimuli induce a transient decrease of transcriptional activity in the neurosecretory neurons of supraoptic nuclei

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JOURNAL OF NEUROCYTOLOGY 1998年第4期27卷 205-217页

作者： Lafarga, M Berciano, MT Garcia-Segura, LM Andres, MA Carmo-Fonseca, M Univ Cantabria Fac Med Dept Anat & Cell Biol Santander 39011 Spain CSIC Inst Cajal Madrid 28006 Spain Univ Lisbon Fac Med Inst Histol & Embryol P-1699 Lisbon Portugal

Administration of hypertonic NaCl solutions by intraperitoneal injection evokes a transient expression of immediate-early genes in the hypothalamic magnocellular neurons of supraoptic nuclei (SON), which is followed by an upregulation of arginine vasopressin synthesis and a general increase in cellular metabolic activity. Here we have analysed the changes that occur in the nucleus of SON neurons during the period of transient Fos expression after injection of hypertonic saline. Within the first 30 minutes after injection, the nuclei become significantly smaller, contain more condensed chromatin and incorporate less H-3-uridine than the controls. By 12 hours these effects are reverting and at 24 hours the nuclei are already more active than the controls. Additionally, we observe an initial decrease in the number of coiled bodies per nucleus within the first 2 hours, followed by a 3-fold increase at 24 hows after injection. As coiled bodies are transcription-dependent subnuclear 'organelles', these results further support the view that injection of hypertonic saline causes a transient inhibition of nuclear activity. Our data show that SON neurons respond to acute osmotic/stress stimuli first with inhibition and then with activation of gene expression. Importantly, inhibition of transcriptional activity occurs simultaneously with maximal accumulation of Fos protein in the nucleus, raising the possibility that activation of c-fos expression may cause repression of target genes.

关键词：细胞核/超微结构基因表达/生理学高渗溶液微量注射显微镜检查免疫电子神经元/生理学神经元/超微结构神经分泌系统/细胞学神经分泌系统/生理学渗透压大鼠 Sprague-Dawley 核糖核蛋白类小核/遗传学视上核/细胞学视上核/生理学转录遗传/生理学氚/诊断应用尿苷/代谢尿苷/药理学水电解质平衡/生理学动物男(雄)性大鼠

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Ontogeny of pulmonary neuroendocrine cells which express the alpha-subunit of guanine nucleotide-binding protein Go

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HISTOCHEMISTRY AND CELL BIOLOGY 1999年第4期111卷 289-295页

作者： Ito, T Udaka, N Kawano, N Nogawa, H Kitamura, H Yokohama City Univ Sch Med Dept Pathol Kanazawa Ku Yokohama Kanagawa 2360004 Japan Chiba Univ Fac Sci Dept Biol Chiba Japan

In order to ascertain that alpha-subunit of guanine nucleotide-binding protein Go (Go alpha)-positive cells in the lung epithelia are pulmonary neuroendocrine cells (PNECs), we carried out an immunohistochemical study in young adult and fetal lungs of rodents and in cultured fetal lung explants. Serial sections showed that Goa-positive cells were immunostained for calcitonin gene-related peptide and serotonin in young adult mouse, rat, and hamster lungs and that these cells are, therefore, PNECs. In the fetal lungs of hamster and mouse, Go alpha-positive PNECs appeared in the epithelium of the lobar bronchus by gestational day 13 in hamster and by day 15.5 in mouse, and they increased with a proximal-to-distal wave during the late fetal period. Explants of immature lung from the fetal hamster on gestational day 11 were cultured. After 2 days of culture, Go alpha-positive PNEC clusters appeared in the main and lobar bronchi and many PNEC clusters were seen after 4 days of culture. To determine the functional significance of Go in the development of the fetal lung, pertussis toxin, a Go inhibitor, was added to the medium, and changes in branching morphogenesis and PNEC development were studied. Although branching morphogenesis was not disturbed by pertussis toxin, the toxin treatment induced large PNEC clusters in the cultured lung explant. In summary, we showed that Goa is a neuroendocrine marker for PNECs and that Goa-positive cells appear along with development of PNECs in fetal hamster lung in vivo and in vitro. The functional significance of Go in the development of fetal lung is obscure, but signals mediated through this GTP-binding protein could be related to some functions of PNECs.

关键词：仓鼠亚科 GTP结合蛋白质α亚单位 Gi-Go GTP结合蛋白质类/分析肺/化学肺/细胞学肺/胚胎学金仓鼠小鼠近交A 黏膜/化学黏膜/细胞学黏膜/胚胎学神经分泌系统/化学神经分泌系统/细胞学神经分泌系统/胚胎学大鼠 Sprague-Dawley 动物小鼠兔大鼠

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Soluble factors guide gonadotropin-releasing hormone axonal targeting to the median eminence

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ENDOCRINOLOGY 2000年第9期141卷 3065-3071页

作者： Gibson, MJ Ingraham, L Dobrjansky, A CUNY Mt Sinai Sch Med Div Endocrinol & Metab New York NY 10029 USA

Axons of GnRH neurons terminate at the median eminence in the medial basal hypothalamus (MBH) of the brain early in development. Similarly, GnRH neurons in grafts of preoptic area (POA) tissue within the third ventricle of hypogonadal mice preferentially innervate the median eminence. Organotypic cocultures of POA explants with other neural tissues suggest that a soluble substance(s) derived from the MBH may be directing this targeting. To begin to identify diffusable chemoattractants, we used preincubated heparin-coated acrylic beads to present specific solutes to POA explants on collagen- and laminin-coated membranes in insert chambers. GnRH axons grew on the membrane in greater number and with longer axons toward conditioned medium from MBH cultures than on the side away from the beads (P < 0.01). In contrast, GnRH axons showed no preferential outgrowth when incubated with beads soaked in control, defined medium. The attraction of MBH-conditioned medium was not generalizable to all neuroendocrine neurons, as it was not seen for galanin immunoreactive outgrowth from POA explants. There also were more GnRH axons toward conditioned medium from mouse brain microvascular endothelial cells, but no difference in axon length. Basic fibroblast growth factor (bFGF), a component of both endothelial cells and ventricular tanycytes, significantly attracted more and longer GnRH axons. Thus, bFGF may be one of the soluble factors directing GnRH outgrowth to the median eminence. However, as with so many other redundancies in the reproductive system, it is unlikely that it is the only targeting factor, as bFGF knockout mice are reported to be reproductively competent.

关键词：动物新生轴突/药物作用细胞存活/药物作用脑室/细胞学脑室/生长和发育脑室/生理学培养基条件性内皮血管/细胞学内皮血管/药物作用成纤维细胞生长因子2/药理学加兰肽/生理学促性腺素释放激素/药理学免疫组织化学正中隆起/细胞学正中隆起/药物作用正中隆起/生长和发育小鼠近交C3H 神经纤维/药物作用神经纤维/生理学神经生长因子类/生理学神经分泌系统/细胞学神经分泌系统/药物作用神经分泌系统/生长和发育器官培养技术视前区/药物作用视前区/生长和发育动物小鼠

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Dopamine transporters participate in the physiological regulation of prolactin

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ENDOCRINOLOGY 2000年第1期141卷 366-374页

作者： Demaria, JE Nagy, GM Lerant, AA Fekete, MIE Levenson, CW Freeman, ME Florida State Univ Dept Biol Sci Tallahassee FL 32306 USA Florida State Univ Dept Nutr Food & Exercise Sci Program Neurosci Tallahassee FL 32306 USA Semmelweis Univ Neuroendocrine Res Lab Dept Human Morphol & Embryol H-1085 Budapest Hungary Hungarian Acad Sci Inst Expt Med Budapest Hungary

Three populations of hypothalamic neuroendocrine dopaminergic (NEDA) neurons, arising from the arcuate and periventricular nuclei of the hypothalamus release dopamine (DA) that acts at the pituitary gland to regulate the secretion of PRL. It is generally accepted that NEDA neurons lack functional DA transporters (DATs), which are responsible for uptake of DA from the synaptic cleft into the presynaptic axon terminal. This study localized DATs to the hypothalamopituitary axis and evaluated the effect of DAT blockade on the hypothalamo-pituitary regulation of PRL. After 7 days of treatment with cocaine (a nonspecific amine transporter blocker) or mazindol(a specific DAT blocker), the relative abundance of PRL messenger RNA (mRNA) in the anterior lobe (AL) of OVX rats was significantly decreased, whereas the relative abundance of tyrosine hydroxylase mRNA in the hypothalamus was significantly increased. The effect of cocaine or mazindol administration on DA turnover and serum PRL concentration was examined in estradiol (E-2)- treated OVX rats. E-2 administration (iv) resulted in a significant increase in serum PRL within 4 h;however, cocaine or mazindol administration abolished the E-2-induced increase of PRL. Cocaine or mazindol significantly increased the concentration of DA at the site of the axon terminals within the median eminence (ME), intermediate lobe (IL) and neural lobe (NL), indicating blockade of uptake. Because formation of DOPAC requires uptake of DA, concentrations of DOPAC in the ME, IL and NL decreased following treatment with either cocaine or mazindol. These data, together with the presence of immunopositive DAT in the ME, pituitary stalk, IL, and NL, suggest that a functional DAT system is present within all three populations of NEDA neurons. Moreover, similarity between the effects of cocaine and mazindol treatment indicate that blockade of the DAT, but not other amine transporters, is responsible for suppression of PRL gene expression and secreti

关键词： 3 4-二羟苯酰乙酸/代谢脑/细胞学脑/代谢载体蛋白质类/生理学可卡因/药理学多巴胺/代谢多巴胺/生理学多巴胺质膜转运蛋白质类多巴胺摄取抑制剂/药理学雌二醇/药理学下丘脑-垂体系统/生理学免疫组织化学马吲哚/药理学正中隆起/代谢膜糖蛋白类膜转运蛋白质类神经组织蛋白质类/生理学神经分泌系统/细胞学神经分泌系统/代谢催乳素/生物合成催乳素/代谢大鼠 Sprague-Dawley 酪氨酸单氧化酶/代谢动物女(雌)性大鼠

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A slow transient potassium current expressed in a subset of neurosecretory neurons of the hypothalamic paraventricular nucleus

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JOURNAL OF NEUROPHYSIOLOGY 2000年第4期84卷 1814-1825页

作者： Luther, JA Halmos, KC Tasker, JG Tulane Univ Dept Cell & Mol Biol New Orleans LA 70118 USA Tulane Univ Neurosci Program New Orleans LA 70118 USA

Type I putative magnocellular neurosecretory cells of the hypothalamic paraventricular nucleus (PVN) express a prominent transient outward rectification generated by an A-type potassium current. Described here is a slow transient outward current that alters cell excitability and firing frequency in a subset of type I PVN neurons (38%). Unlike most of the type I neurons (62%), the transient outward current in these cells was composed of two kinetically separable current components, a fast activating, fast inactivating component, resembling an A-type potassium current, and a slowly activating [10-90% rise time: 20.4 +/- 12.8 (SE) ms], slowly inactivating component (time constant of inactivation: tau = 239.0 +/- 66.1 ms). The voltage dependence of activation and inactivation and the sensitivity to block by 4-aminopyridine (5 mM) and tetraethylammonium chloride (10 mM) of the fast and slow components were similar. Compared to the other type I neurons, the neurons that expressed the slow transient outward current were less excitable when hyperpolarized, requiring larger current injections to elicit an action potential (58.5 +/- 13.2 vs. 15.4 +/- 2.4 pA;250-ms duration;P < 0.01), displaying a longer delay to the first spike (184.9 +/- 15.7 vs. 89.7 +/- 8.8 ms with 250- to 1,000-ms, 50-pA current pulses;P, 0.01), and firing at a lower frequency (18.7 +/- 4.6 vs. 37.0 +/- 5.5 Hz with 100-pA current injections;P < 0.05). These data suggest that a distinct subset of type I PVN neurons express a novel slow transient outward current that leads to a lower excitability. Based on double labeling following retrograde transport of systemically administered fluoro-gold and intracellular injection of biocytin, these cells are neurosecretory and are similar morphologically to magnocellular neurosecretory cells, although it remains to be determined whether they are magnocellular neurons.

关键词： 4-氨基吡啶/药理学导电性神经元/生理学神经分泌系统/细胞学神经分泌系统/生理学下丘脑室旁核/细胞学下丘脑室旁核/生理学膜片钳术钾/生理学大鼠 Sprague-Dawley 四乙基铵/药理学时间因素动物男(雄)性大鼠

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Modeling study of exocytosis in neuroendocrine cells: Influence of the geometrical parameters

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BIOPHYSICAL JOURNAL 2000年第4期79卷 1771-1786页

作者： Segura, J Gil, A Soria, B Univ Miguel Hernandez Inst Bioingn Alicante 03202 Spain

Exocytosis in neuroendocrine cells is a process triggered by Ca2+. A Monte Carlo Simulation of secretion has been developed which, together with the diffusion of calcium, buffered by endogenous and/or exogenously added chelators, also accounts for the dynamics of exocytosis for a pool of readily releasable vesicles. Different distributions of channels and vesicles (random or correlated) are studied. A local study of exocytosis is carried out by obtaining capacitance time courses for the different types of release-ready vesicle pools (correlated or not with Ca2+ channels). Also, depending upon the kinetic constants for the exocytotic process, we study the levels of local Ca2+ needed to trigger secretion. Our simulations show that a strong heterogeneity in the calcium concentrations at the different sites of exocytosis is a requirement for reproducing the experimentally observed biphasic response in chromaffin cells in situ (Voets, T., E. Neher, and T. Moser. 1999. Neuron. 23:607-675). Correlated nonuniform distributions of channels and vesicles and the existence of diffusion barriers are shown to quantitatively explain the experimental data on chromaffin cells in situ. The first description requires a deeply heterogeneous distribution, with vesicles attached to the channels or far from them, but never at middle distances. The second description is able to reproduce biphasic release even for uniformly (readily releasable) distributed vesicles. We quantify the degree of inhomogeneity in the distribution of vesicles and how porous the diffusion barriers should be to account for the observed biphasic response.

关键词：生物物理学缓冲剂钙信号扩散胞吐作用/生理学模型神经学神经分泌系统/细胞学神经分泌系统/生理学动物

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