The endocrine regulation of salt and water balance in aquatic organisms

水生生物盐水平衡的内分泌调节

• 批准号: RGPIN-2014-04073
• 负责人: Kelly, Scott
• 金额: $ 2.91万
• 依托单位: York University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=587585
• 关键词: endocrine; regulation; salt; water; balance

My research program examines how endocrine factors (e.g. hormones) allow aquatic animals to maintain salt and water balance. To put this in context, all freshwater (FW) animals and a great many marine species live under conditions where passive salt movement either into our out of the body will create life-threatening problems if not held in check by tissues and organs that specialize in salt transport. For example, the salt content (e.g. ions such as sodium, chloride and calcium) of freshwater (FW) is considerably lower than that of animal blood and ions are lost from the body to the surroundings by passive diffusion. In contrast, many seawater (SW) animals suffer the opposite problem because in these species SW is saltier than blood, and ions diffuse into the animal. Furthermore, aquatic animals may live where natural alterations in environmental salt content occur (e.g. changing tides in an estuary) or where human disturbance (e.g. road salting) is changing water salt content. In all these circumstances, the action of hormones on specialized ion transporting tissues adjusts the form and function of the tissues so as to allow the maintenance of salt and water balance. In aquatic animals, these specialized tissues include epithelia of the gill, kidney, gastrointestinal tract and skin. Epithelial tissues establish barriers that separate and regulate the movement of biological material between fluid compartments (e.g. the gill epithelium separates blood and water and regulates ion movement between them). Transepithelial ion transport, from one fluid compartment to another, occurs by two routes. The first is through cells (the transcellular pathway) and the second is between cells (the paracellular pathway). Transcellular ion transport is governed by a complex suite of transport proteins and ion channels that are well described in aquatic animals, as is the effect of hormones on their function. The paracellular route is governed by proteins of the tight junction (TJ) complex in vertebrates or septate junction (SJ) complex in invertebrates. In contrast to transcellular transport proteins, very little is known about TJ and SJ proteins in aquatic animals, and almost nothing is known about how (or what) endocrine factors influence them. This is alarming because the permeability of the paracellular pathway in aquatic animals is broadly acknowledged to play a vital role in the regulation of salt and water balance. As such we are presented with a serious gap in our fundamental knowledge of how aquatic animals function in their natural environment and how these organisms are equipped to cope with environmental change. My work addresses this lack of knowledge by identifying important TJ and SJ proteins in aquatic animals and looking closely at the endocrine regulation of TJ and SJ permeability using established and new state-of-the-art techniques. In this regard, our research is important to anyone who has an interest in how aquatic organisms maintain "homeostasis" (i.e. internal stability) or who are interested in how biological material moves across the epithelial barriers of aquatic animals. This is a broad populace that will range from those with basic research interests, to those who investigate the effects of pollutants and the impact of human activity on aquatic organisms, as well as those that seek to optimize the delivery of biological material (e.g. drugs) to aquatic organisms via the paracellular pathway.

我的研究项目研究内分泌因素（如激素）如何使水生动物保持盐和水的平衡。为了把这一点放在上下文中，所有的淡水（FW）动物和许多海洋物种生活在这样的条件下，即被动盐运动进入或离开身体，如果不被专门负责盐运输的组织和器官控制，将造成危及生命的问题。例如，淡水（FW）的盐含量（例如，诸如钠、氯和钙的离子）显著低于动物血液的盐含量，并且离子通过被动扩散从身体损失到周围环境。相比之下，许多海水（SW）动物遭受相反的问题，因为在这些物种中，SW比血液更咸，离子扩散到动物中。此外，水生动物可能生活在环境盐含量发生自然变化的地方（例如河口的潮汐变化）或人类干扰（例如道路盐渍）正在改变水盐含量的地方。在所有这些情况下，激素对专门的离子运输组织的作用调节了组织的形式和功能，以维持盐和水的平衡。在水生动物中，这些特化组织包括鳃、肾、胃肠道和皮肤的上皮。上皮组织建立了分隔和调节流体隔室之间的生物材料的运动的屏障（例如，鳃上皮分隔血液和水，并调节它们之间的离子运动）。从一个流体室到另一个流体室的跨上皮离子转运通过两种途径发生。第一种是通过细胞（跨细胞途径），第二种是细胞之间（细胞旁途径）。跨细胞离子转运由一套复杂的转运蛋白和离子通道控制，这些转运蛋白和离子通道在水生动物中有很好的描述，激素对其功能的影响也是如此。细胞旁途径由脊椎动物中的紧密连接（TJ）复合体或无脊椎动物中的分隔连接（SJ）复合体的蛋白质控制。与跨细胞转运蛋白相反，对水生动物中的TJ和SJ蛋白知之甚少，几乎不知道内分泌因素如何（或什么）影响它们。这是令人担忧的，因为水生动物中细胞旁途径的渗透性被广泛认为在盐和水平衡的调节中起着至关重要的作用。因此，我们对水生动物在自然环境中的功能以及这些生物如何科普环境变化的基本知识存在严重差距。我的工作通过识别水生动物中重要的TJ和SJ蛋白质，并使用现有和新的最先进的技术密切关注TJ和SJ渗透性的内分泌调节来解决这种知识的缺乏。在这方面，我们的研究对于任何对水生生物如何保持“稳态”（即内部稳定性）感兴趣的人都很重要，或者对生物材料如何穿过水生动物的上皮屏障感兴趣。这是一个广泛的人群，范围从那些具有基础研究兴趣的人，到那些调查污染物的影响和人类活动对水生生物的影响的人，以及那些寻求通过细胞旁途径优化生物材料（例如药物）向水生生物递送的人。