Mechanisms of Cell Volume Regulation in Liver

肝脏细胞体积调节机制

• 批准号: 7455422
• 负责人: STEVEN D LIDOFSKY
• 金额: $ 38万
• 依托单位: UNIVERSITY OF VERMONT & ST AGRIC COLLEGE
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-12-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7455422
• 关键词: Actins; Acute; Address; Anatomy; Architecture; Arts; Attenuated; Binding; Biosensor; Blood Vessels; Cell Survival; Cell Volumes; Cell membrane; Cells; Chloride Channels; Chronic; Complex; Condition; Cytoskeletal Modeling; Cytoskeleton; Cytosolic Phospholipase A2; Disease; Disruption; Electrolytes; Extracellular Signal Regulated Kinases; Family; Focal Adhesion Kinase 1; Foundations; Functional disorder; Goals; Guanosine Triphosphate Phosphohydrolases; HTATIP gene; Hepatic; Hepatocyte; Human; Image; Injury; Integrins; Ion Channel; Kinetics; Laboratories; Life; Liquid substance; Liver; Liver diseases; Maintenance; Mediating; Mediator of activation protein; Metabolic; Metabolism; Molecular; Movement; Nutrient; Organ; PLA2G4A gene; Pathway interactions; Phospholipase; Phospholipase A2; Phosphotransferases; Physiological; Potassium Chloride; Process; Protein Inhibition; Receptor Signaling; Recovery; Regulation; Research; Role; Sampling; Signal Transduction; Site; Stress; Swelling; Testing; Time; Travel; Tyrosine Phosphorylation; Vesicle; Work; base; bile formation; cell motility; extracellular; human PLA2G4A protein; liver function; novel; phospholipase C gamma; polymerization; prevent; response; restoration; rho; sensor; src-Family Kinases

The ability to regulate volume is critical for the survival of cells. This is particularly true in the liver, which is subjected to dynamic changes in osmotic load as a result of its role in nutrient processing, metabolism, and bile formation. Disordered volume control leads to irreversible cell swelling that is a hallmark of acute and chronic liver injury. Given the importance of this problem, the goals of this project are to understand how hepatocellular volume, and by extension organ function, are maintained during osmotic stress. It is known that such stress imposes dramatic changes in cell architecture, and that plasma membrane ion channels are crucial to volume restoration after hepatocellular swelling. Recent work from this laboratory has suggested a novel role for the tyrosine kinase Src in coordinating these actions. This proposal will test the hypothesis that Src serves as a molecular switch that relays signals from volume-sensitive sensors to downstream effectors that reorganize the cytoskeleton and activate fluid and electrolyte movement through potassium and chloride channels. This maintains cell volume within a physiological state. The Specific Aims are: (1) to establish the kinetics and cellular localization of volume-sensitive Src activation, (2) to determine the role of Src in volume-sensitive cytoskeletal reorganization, and (3) to elucidate how Src regulates the activation of volume-sensitive ion channels. Studies in Aim 1 will determine how Src influences the volume-sensitive cellular localization and regulatory function of integrins, focal adhesion kinase (FAK), and the Src effectors Vav and phospholipase C (PLC) gamma. It will also be tested whether the expression of Src or its effectors is altered in human liver diseases manifested by hepatocyte ballooning. Studies in Aim 2 will test whether inhibition of Src effectors modifies swelling-induced actin dynamics, and whether inhibition of these dynamics attenuates volume recovery. Studies in Aim 3 will determine whether Src-dependent extracellular signal receptor (ERK) kinases are regulated upon swelling by PLC gamma and/or Vav, and whether the ERK effector phospholipase A2 regulates volume-sensitive potassium and chloride channels. The proposed studies are expected to provide an integrated picture of mechanisms by which cell volume is regulated in the liver. Since cell volume control is essential to the maintenance of organ level function, an understanding of these mechanisms will provide new ways to prevent organ dysfunction in the setting of liver disease.

调节体积的能力对于细胞的生存至关重要。这在肝脏中尤其如此，肝脏 由于其在营养加工、代谢和代谢过程中的作用，渗透负荷会发生动态变化。 胆汁的形成。容量控制紊乱会导致不可逆的细胞肿胀，这是急性和慢性疾病的标志。 慢性肝损伤。鉴于这个问题的重要性，该项目的目标是了解如何 在渗透压过程中，肝细胞体积以及器官功能得以维持。我们都知道 这种压力会导致细胞结构发生巨大变化，并且质膜离子通道 对肝细胞肿胀后体积恢复至关重要。该实验室最近的工作表明 酪氨酸激酶 Src 在协调这些作用中发挥了新作用。该提案将检验假设 Src 充当分子开关，将信号从体积敏感传感器中继到下游 重组细胞骨架并通过钾激活液体和电解质运动的效应器 和氯离子通道。这将细胞体积维持在生理状态内。具体目标是： (1) 建立体积敏感 Src 激活的动力学和细胞定位，(2) 确定 Src 在体积敏感的细胞骨架重组中的作用，以及 (3) 阐明 Src 如何调节 体积敏感离子通道。目标 1 的研究将确定 Src 如何影响体积敏感 整合素、粘着斑激酶 (FAK) 和 Src 效应子的细胞定位和调节功能 Vav 和磷脂酶 C (PLC) γ。还将测试Src或其效应子的表达是否 在以肝细胞膨胀为表现的人类肝脏疾病中发生改变。目标 2 的研究将测试是否 抑制 Src 效应子会改变肿胀诱导的肌动蛋白动力学，以及抑制这些动力学是否会改变 削弱容量恢复。目标 3 的研究将确定 Src 依赖性细胞外信号是否 受体 (ERK) 激酶在肿胀时受 PLC γ 和/或 Vav 的调节，并且 ERK 是否 效应磷脂酶 A2 调节容量敏感的钾通道和氯通道。拟议的 预计研究将提供细胞体积调节机制的综合图景 肝。由于细胞体积控制对于维持器官水平功能至关重要，因此了解 这些机制将为预防肝病时器官功能障碍提供新的方法。