雌激素对MAPK信号转导通路的作用机制

雌激素可以通过基因组作用和非基因组作用对细胞功能起调节作用。本文主要综述了其非基因组作用,即通过膜受体激活细胞内MAPK(ERK、p38、JNK)信号传导通路的过程。雌激素对ERK主要起促进作用,引起细胞增殖、分化以及血管扩张等生物学效应;对p38也起促进作用,而在不同的细胞中对JNK的作用不同,进而调节细胞凋亡、癌症发生等生命现象。     

雌激素的非基因组途径在哺乳动物雌性生殖过程中的作用机制

雌激素的非基因组调节模式在雌性生殖系统中广泛存在．雌激素通过基因组、非基因组及两种调节模式的整合在不同组织中行使多种生理功能．卵巢中雌激素能通过非基因组效应对卵细胞起到保护作用．子宫中雌激素对多种基因的表达都是通过非基因组模式．对雌激素非基因组效应的研究将有利于进一步了解雌激素的作用机制．     

雌激素心血管作用的研究进展

雌激素受体广泛分布于心血管系统,具有抗心律失常作用,抗动脉粥样硬化效应和舒血管效应,并可调控动脉压力感受器反射,雌激素通过基因组机制和非基因组机制发挥心血管保护效应。     

内源性气体硫化氢在中枢神经系统中的作用

内源性硫化氢(H2S)可以刺激神经细胞cAMP水平增加,提高NMDA受体介导的突触后兴奋性电位,提高诱导海马长时程增强。H2S不仅具有神经调节剂的功能,还有神经保护剂的功能。H2S自身并不能将细胞从氧化应激中解救出来,但是它能通过提高胞内有效的抗氧化剂——还原型谷胱苷肽的含量而起到保护神经元的作用。对H2S的研究刚刚起步,对其在神经系统中的作用机制开展研究将有助于了解其在神经元保护方面所起的作用。     

雌激素受体在垂体中的作用

垂体和性腺是生殖轴重要组成部分,两者之间的协同与制衡是动物维持正常生长发育的保证。性腺产生的雌激素可以反馈调控垂体神经内分泌活动。近年来,随着基因芯片和差异表达谱分析技术的发展,垂体内雌激素受体介导的基因调控网络不断取得进展,垂体生殖生理功能备受关注。通过综述雌激素及其受体在促性腺激素、催乳素、生长激素合成分泌中的调控作用,以及雌激素对垂体生长发育的影响,探讨雌激素受体通过垂体影响生殖过程,希望能为进一步研究雌激素及其受体的生殖生理作用开拓思路。     

雌激素受体α36

雌激素受体(estrogen receptor,ER)属核受体超家族成员之一,主要包括ER-α66、ER-α36、ER-α46和ER-β,它们通过与相应配体——雌激素的结合,在人体中发挥各种不同的功能。ER-α36是最近新发现的一种雌激素受体,它是ER-α66的独特变异体,主要分布于细胞膜和胞浆中,能抑制ER-α66和ER-β的反式激活功能,并参与雌激素的非基因组活性信号通路,介导了临床乳腺癌抗雌激素药物治疗抵抗。     

雌激素的神经保护作用

雌激素是一种性激素 ,它的主要生理作用是促进女性生殖器官的发育与成熟 ,刺激女性副性征出现 ,并影响代谢功能。然而 ,雌激素的作用并不仅局限于此 ,它在大脑的正常发育、分化中也起着重要作用。目前发现 ,雌激素除了能通过调节下丘脑ＧｎＲＨ神经元的活动影响生殖外 ,对大脑其它神经元还有着电生理、神经营养和代谢等多方面作用 ,而其中备受关注的是它对中枢神经元的保护作用。临床证实 ,雌激素替代治疗 (ＥＲＴ)可以明显改善绝经后妇女的认知功能 ,对于老年性痴呆病 (Ａｌｚｈｅｉｍｅｒ’ｓｄｉｓｅａｓｅ ,ＡＤ)、缺血性脑损伤以及神经…     

雌激素相关受体及其在雌激素信号转导体系中的作用

雌激素生理效应的发挥是通过靶细胞雌激素受体介导的;但近年来发现,孤儿受体中的一种枛雌激素相关受体也参与了雌激素信号转导体系,并与雌激素受体传导通路相互交叉、相互影响,在雌激素相关生理和病理过程的发生和调节中也发挥着重要的作用。本文将就雌激素相关受体的组成、结构、功能及其与雌激素相关病理过程间的关系进行综述。     

雌激素膜受体介导的非基因组效应

雌激素受体（estrogen receptor,ER）是固醇类激素受体蛋白超家族的成员之一,分布于许多组织,介导了大部分已知的雌激素效应.ER主要定位于胞质中,但是近些年的研究发现在部分组织的细胞膜上也存在雌激素受体,称为“膜受体（mER）”.ER在其配体雌二醇（E2）的诱导下,可以通过“基因组”和“非基因组”两种方式介导大部分的生理效应,胞质中的ER可与DNA反应元件直接作用产生基因组效应,而mER主要通过信号分子介导雌激素的非基因组效应.该文介绍ER的结构、ER介导的非基因组效应的生理功能以及前景展望.     

Function of thyroid hormone transporters in the central nervous system

Background

Iodothyronines are charged amino acid derivatives that cannot passively cross a phospholipid bilayer. Transport of thyroid hormones across plasma membranes is mediated by integral membrane proteins belonging to several gene families. These transporters therefore allow or limit access of thyroid hormones into brain. Since thyroid hormones are essential for brain development and cell differentiation, it is expected that genetic deficiency of such transporters would result in neurodevelopmental derangements.

Scope of review

We introduce concepts of thyroid hormone transport into the brain and into brain cells. Important thyroid hormone transmembrane transporters are presented along with their expression patterns in different brain cell types. A focus is placed on monocarboxylate transporter 8 (MCT8) which has been identified as an essential thyroid hormone transporter in humans. Mutations in MCT8 underlie one of the first described X-linked mental retardation syndromes, the Allan–Herndon–Dudley syndrome.

Major conclusions

Thyroid hormone transporter molecules are expressed in a developmental and cell type-specific pattern. Any thyroid hormone molecule has to cross consecutively the luminal and abluminal membranes of the capillary endothelium, enter astrocytic foot processes, and leave the astrocyte through the plasma membrane to finally cross another plasma membrane on its way towards its target nucleus.

General significance

We can expect more transporters being involved in or contributing to in neurodevelopmental or neuropsychiatric disease. Due to their expression in cellular components regulating the hypothalamus–pituitary–thyroid axis, mutations and polymorphisms are expected to impact on negative feedback regulation and hormonal setpoints. This article is part of a Special Issue entitled Thyroid hormone signalling.     

The emergence of neural activity and its role in the development of the enteric nervous system

The enteric nervous system (ENS) is a vital part of the autonomic nervous system that regulates many gastrointestinal functions, including motility and secretion. All neurons and glia of the ENS arise from neural crest-derived cells that migrate into the gastrointestinal tract during embryonic development. It has been known for many years that a subpopulation of the enteric neural crest-derived cells expresses pan-neuronal markers at early stages of ENS development. Recent studies have demonstrated that some enteric neurons exhibit electrical activity from as early as E11.5 in the mouse, with further maturation of activity during embryonic and postnatal development. This article discusses the maturation of electrophysiological and morphological properties of enteric neurons, the formation of synapses and synaptic activity, and the influence of neural activity on ENS development.     

HVJ-envelope vector for gene transfer into central nervous system

To overcome some problems of virus vectors, we developed a novel non-viral vector system, the HVJ-envelope vector (HVJ-E). In this study, we investigated the feasibility of gene transfer into the CNS using the HVJ-E both in vitro and in vivo. Using the Venus reporter gene, fluorescence could be detected in cultured rat cerebral cortex neurons and glial cells. In vivo, the reporter gene (Venus) was successfully transfected into the rat brain by direct injection into the thalamus, intraventricular injection, or intrathecal injection, without inducing immunological change. When the vector was injected after transient occlusion of the middle cerebral artery, fluorescence due to EGFP gene or luciferase activity could be detected only in the injured hemisphere. Finally, luciferase activity was markedly enhanced by the addition of 50 U/ml heparin (P<0.01). Development of efficient HVJ-E for gene transfer into the CNS will be useful for research and clinical gene therapy.     

Immunohistochemical localization of Bis protein in the rat central nervous system

We studied the distribution of Bis (Bcl-2 interacting death suppressor) protein in the adult rat brain and spinal cord using immunohistochemistry. Immunoreactivity was observed in specific neuronal populations in distinct nuclei. The most intensely labeled cells were associated with the motor system, including most cranial nerve motor nuclei, Purkinje cells of the cerebellum, the red nucleus, and the ventral motor neurons of the spinal cord. Bis protein was also expressed in several structures associated with the ventricular system, including the subventricular zone of the lateral ventricle and its rostral extension, in the subcommissural organ, and in tanycytes, radial glial cells in the hypothalamus. Using double-labeling techniques, Bis-immunoreactive cells in the rostral migratory stream, coexpressing Bcl-2, were confirmed as glial fibrillary acidic protein-positive astrocytes comprising the glial tubes. The widespread distribution of Bis suggests that this protein has broader functions in the adult rat central nervous system than previously thought, and that it could be associated with a particular role in the rostral migratory system.J.-H. Lee and M.-Y. Lee contributed equally to this study. This work was supported by the KOSEF through the Cell Death Disease Research Center of MRC at the Catholic University of Korea (R13-2002-005-01001-0) and the Catholic Medical Center Research Foundation grant made in the program year of 2002     

Cellular distribution and developmental expression of AMP-activated protein kinase isoforms in mouse central nervous system

The mammalian AMP-activated protein kinase is a heterotrimeric serine/threonine protein kinase with multiple isoforms for each subunit (alpha, beta, and gamma) and is activated under conditions of metabolic stress. It is widely expressed in many tissues, including the brain, although its expression pattern throughout the CNS is unknown. We show that brain mRNA levels for the alpha2 and beta2 subunits were increased between embryonic days 10 and 14, whereas expression of alpha1, beta1, and gamma1 subunits was consistent at all ages examined. Immunostaining revealed a mainly neuronal distribution of all isoforms. The alpha2 catalytic subunit was highly expressed in neurons and activated astrocytes, whereas the alpha1 catalytic subunit showed low expression in neuropil. The gamma1 noncatalytic subunit was highly expressed by neurons, but not by astrocytes. Expression of the beta1 and beta2 noncatalytic subunits varied, but some neurons, such as granule cells of olfactory bulb, did not express detectable levels of either beta isoform. Preferential nuclear localization of the alpha2, beta1, and gamma1 subunits suggests new functions of the AMP-activated protein kinase, and the different expression patterns and cellular localization between the two catalytic subunits alpha1 and alpha2 point to different physiological roles.     

The role of IFN-gamma in immune responses to viral infections of the central nervous system

Interferon (IFN)-γ, is not only a marker of T_H1 CD4, CD8 and natural killer (NK) cells, it is also a critical antiviral mediator which is central to the elimination of viruses from the CNS. In this review, we describe IFN-γ, its receptor, signal transduction from receptor engagement, and antiviral downstream mediators. We demonstrate that although neurons are post-mitotic and non-renewing, they respond to IFN-γ in a fashion similar to peripheral fibroblasts or lymphocytes. We have illustrated this review with details about studies on the role(s) of IFN-γ in the pathogenesis of measles virus (MV), herpes simplex virus (HSV) type 1, and vesicular stomatitis virus (VSV) infections of the CNS. For VSV infection, IFN-γ signals through Jaks 1 and 2 and STAT1 to activate (interferon regulatory factor) IRF-1; although viral protein synthesis is inhibited, PKR is not a critical mediator in the antiviral response to VSV in murine neurons. In contrast, induction of nitric oxide synthase (NOS) type 1 and its production of nitric oxide is essential in the elimination of viruses from neurons.     

Neurogenesis in the adult central nervous system

Contrary to the long-held dogma, neurogenesis occurs throughout adulthood, and neural stem cells reside in the adult central nervous system (CNS) in mammals. The developmental process of the brain may thus never end, and the brain may be amenable to repair. Neurogenesis is modulated in a wide variety of physiological and pathological conditions, and is involved in processes such as learning and memory and depression. However, the relative contribution of newly generated neuronal cells to these processes, as well as to CNS plasticity, remains to be determined. Thus, not only neurogenesis contributes to reshaping the adult brain, it will ultimately lead us to redefine our knowledge and understanding of the nervous system.     

Effects of interferon-gamma on the central nervous system

Pleotropic cytokine IFN-gamma is synthesized not only by activated immunocompetent cells but also by elements of CNS (endothelial cells of brain, glial cells, neurons). Primary structure of neuronal and immune IFN-gamma are similar. The molecular identity of this cytokine receptors on neuronal and immune cells is found. These facts testify of interrelation of two physiological systems. The central effects of IFN-gamma are realized in modulation both immune and controle-regulation processes. One of important immunomodulation properties of IFN-gamma is its ability to induce expression of antigenes of MHC class II on neuronal cells, which is characteristic only for this cytokine. The participation of IFN-gamma in immune reactions of CNS also is carried out at the expense of amplification under its influence of superoxide production, NO and prostaglandine synthesis, expression in astrocytes and microglial cells of ICAM adgesive molecule. Control-regulation function of cytokine is realized at level of cell elements of brain, nerve/endocrine system. Auto/parakrine activity of neuronal IFN-gamma is directed on maintenance homeostasis in CNS. It participates in regulation of processes connected to the daily allowance biorhythmes, it is revealed in work of "internal clocks". The cytokine participation in immunogenesis processes [symbol: see text] and control-regulation reactions has a number of common mechanisms. IFN-gamma is immunomodulator and from an other hand it is neuromodulator.     

Transneuronal uptake of horseradish peroxidase in the central nervous system of dipterous insects

Summary Horseradish peroxidase (HRP) applied to lesioned neurons in the retina and thoracic ganglia of the flies Musca, Calliphora and Drosophila labeled axon terminals, dendrites and perikarya of the severed neurons after anterograde or retrograde passage. In addition, HRP reaction product secondarily labeled intact neurons that are contiguous with injured nerve cells. In many cases labeling of optic lobe neurons remote from primarily filled ones was also seen (here called tertiary labeling). HRP labeling was extensive and both primarily and transneuronally filled neurons could be resolved in almost as much detail as Golgi-impregnated or cobalt-silver-labeled cells. Electron microscopy showed that in both primarily and secondarily filled neurons, reaction product was distributed diffusely in the cytoplasm.Transneuronal uptake of HRP was specific to certain types of neurons in the brain and thus displayed certain pathways. The pathways resolved by transneuronal labeling with HRP extend from the optic lobes to the thoracic ganglia and include visual neurons previously identified electrophysiologically and anatomically.Transneuronal HRP uptake, although believed to occur in vivo, could not be shown to be dependent on synaptic activity. Three other heme peptides tested were taken up by injured neurons, but showed no transneuronal labeling: lactoperoxidase, cytochrome c, and microperoxidase.     

Progestin, estrogen and androgen G-protein coupled receptors in fish gonads

The identities of the membrane receptors mediating the majority of rapid, cell surface-initiated, nongenomic (i.e. nonclassical) steroid actions described to date are unclear. Two novel 7-transmembrane spanning proteins, representing two distinct classes of steroid membrane receptors, membrane progestin receptor alpha (mPRalpha) and a membrane estrogen receptor (mER), GPR30, have recently been identified in several vertebrate species. Evidence that both receptors activate G-proteins and function as G-protein coupled receptors (GPCRs) is briefly reviewed. New data on progestin actions on fish gametes suggest a widespread involvement of mPRalpha in oocyte maturation and sperm hyperactivity in this vertebrate group. Information on the second messenger pathways activated upon estrogen binding to a membrane estrogen receptor in croaker gonads and preliminary evidence for the presence of a GPR30-like protein in fish gonads are discussed. Finally, initial characterization of the ligand binding, G-protein activation and molecular size of a membrane androgen receptor (mAR) in croaker ovaries suggests the presence of a third unique steroid receptor in fish gonads that also may function as a GPCR.