Gene networks involved in hypothalamic plasticity in response to dehydration; assessing the in vivo functions of candidate nodal genes.

这个项目背后的驱动力是需要快速利用基因组信息，以获得生理上的理解。我们现在知道哺乳动物大约有3万个基因。这些数据提出了两个问题，首先，这些基因在何时何地表达，其次，这些基因有什么作用？我们已经在一个强大的模型系统中解决了这些问题，即下丘脑的生理挑战抗利尿激素（VP）神经元。当动物脱水时，肽激素VP被释放，并通过血流到达位于肾脏的特定受体目标，在那里它减少了水的排泄，从而促进了水的保护。这伴随着VP神经元形态、电生理特性、生物合成和分泌活性的大量变化。我们希望了解这种功能可塑性及其在基因差异表达方面的生理后果。我们已经使用了微阵列技术，使我们能够在一次分析中观察成千上万个基因的表达。因此，我们编制了目录，代表了在下丘脑和垂体的不同区域表达的RNA群体的全面描述。此外，我们还确定了由于慢性脱水而上调或下调的转录本。这些目录是研究VP生理学各个方面的重要资源，特别是心血管内稳态的中枢神经-体液控制。基于无偏数学标准，我们选择了4个基因进行进一步研究，因为它们是基因网络中的关键枢纽或节点，我们假设它们可能参与调节和调节下丘脑的功能可塑性。为了检验这一假设，我们将：1。使用独立的方法检查数组数据是否正确；2. 利用基因转移到整个生物体中，结合最新的非侵入性监测技术，确定目标基因产物活性增加或减少对心血管综合控制的功能后果。这将是第一次，基于微阵列输出，基因网络将在整个动物生理系统的背景下进行功能研究。毫无疑问，这些数据将使我们更好地理解与健康和疾病状态下生理系统可塑性有关的基因网络。

The driving force behind this project is the need to rapidly exploit genomic information in order to obtain physiological understanding. We now know that mammals have approximately 30,000 genes. These data prompt two questions, firstly, where and when are these genes expressed, and secondly, what do these genes do? We have addressed these questions in a robust model system, namely the physiologically challenged vasopressin (VP) neurones of the hypothalamus. When an animal is dehydrated, the peptide hormone VP is released and travels through the blood stream to specific receptor targets located in the kidney, where it reduces the excretion of water, thus promoting water conservation. This is accompanied by a plethora of changes in the morphology, electrophysiological properties and biosynthetic and secretory activity of VP neurones. We wish to understand this functional plasticity and its physiological consequences in terms of the differential expression of genes. We have used microarray techniques that allow us to look at the expression of tens of thousands of genes in a single assay. We have thus compiled catalogues that represent comprehensive descriptions of the RNA populations expressed in different regions of the hypothalamus and pituitary. Further, we have identified transcripts that are either up- or down-regulated as a consequence of chronic dehydration. These catalogues are an important resource for researchers working on all aspects of VP physiology, particularly the central neuro-humoral control of cardiovascular homeostasis. Based on unbiased mathematical criteria, we have selected 4 genes for further study on the basis that they are key hubs, or nodes, in a gene network that, we hypothesise, might be involved in regulating and mediating hypothalamic functional plasticity. In order to test this hypothesis, we will: 1. check that the array data are correct using independent methods; 2. use gene transfer into the whole organism, coupled with the latest non-invasive monitoring technologies to determine the functional consequences of the increased or decreased activity of target gene products in terms of integrated cardiovascular control. This will be the first time that, based on a microarray output, a gene network will be studied functionally in the context of a whole animal physiological system. The data will undoubtedly lead to a better understanding of gene networks involved in the plasticity of a physiological system in health and disease states.