Ca2+ Sparks as Regulators of Airway Contractility

Ca2 Sparks 作为气道收缩性的调节剂

• 批准号: 6903624
• 负责人: Ronghua ZhuGe
• 金额: $ 31.8万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-06-10 至 2008-05-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6903624
• 关键词: biosensor device; calcium channel; calcium flux; chloride channels; confocal scanning microscopy; genetically modified animals; ion transport; laboratory mouse; lung; membrane activity; membrane channels; membrane potentials; mitochondria; muscle cells; muscle contraction; muscle relaxation; potassium channel; receptor coupling; respiratory function; sarcoplasmic reticulum; smooth muscle; voltage gated channel

DESCRIPTION (provided by applicant): This project seeks to understand the mechanisms by which the contractility of airway smooth muscle (ASM) is controlled and regulated. The present proposal focuses on the highly localized and short-lived Ca2+ events (Ca2+ sparks), resulting from the opening of ryanodine receptors (RyRs) in the sarcoplasmic reticulum membrane, and their interactions with nearby Ca2+-activated ion channels in the plasma membrane. As in vascular smooth muscle, Ca2+ sparks activate a small number of large-conductance K+ (BK) channels in the spark microdomain to generate spontaneous transient outward currents (STOCs) which hyperpolarize the membrane in ASM. Recently we have identified another important target of Ca2+ sparks in ASM, i.e. Ca2+-activated CI- (CIca) channels which cause spontaneous transient inward currents (STICs) and thus depolarize the membrane. Accordingly, the central hypothesis of this proposal is that Ca2+ sparks coordinate the activation of membrane channels to regulate airway contractility. An integrated approach using high-speed digital Ca2+ imaging with simultaneous patch-clamping, and also 2D and 3D protein localization, will be applied using normal and transgenic mouse models. Furthermore, a physiological airway preparation, i.e., lung slices, will be employed to investigate the role of Ca2+ sparks in regulating contractility of airways themselves. Our specific objectives are to uncover the biophysics of RyRs underlying Ca2+ sparks using our newly developed signal mass approach (Aim 1); to determine the functional and spatial relationships of RyRs to BK channels and CIca channels (Aims 2 and 3); and to determine the physiological role of Ca2+ sparks in airways (Aim 4). We expect that these studies will provide new knowledge which could lead to development of novel therapeutic approaches for asthma and other bronchospasitc disorders.

描述（由申请人提供）：该项目旨在了解控制和调节气道平滑肌（ASM）收缩力的机制。本提案的重点是高度局部和短暂的Ca2+事件（Ca2+火花），这是由于肌浆网膜中ryanodine受体（RYRS）的开放以及它们与附近Ca2+ Ca2+ Ca2+激活离子通道的相互作用。像在血管平滑肌中一样，Ca2+火花激活了火花微域中的少量大传导k+（bk）通道，以生成自发的瞬态外向电流（stocs），这些电流（stocs）超极化ASM中的膜。最近，我们确定了ASM中Ca2+火花的另一个重要目标，即Ca2+激活的CI-（CICA）通道，该通道引起自发的瞬时向内电流（STICS），从而使膜去极化。因此，该提案的中心假设是Ca2+ SparkS协调了调节气道收缩力的膜通道的激活。使用高速数字CA2+成像的集成方法，并将使用正常和转基因小鼠模型应用于同时的贴片夹以及2D和3D蛋白质定位。此外，将采用生理气道准备，即肺切片，以调查Ca2+火花在调节气道本身的收缩性中的作用。我们的具体目标是使用我们新开发的信号质量方法（AIM 1）揭示Ryrs基础CA2+火花的生物物理学；确定RYRS与BK通道和CICA通道的功能和空间关系（目标2和3）；并确定Ca2+火花在气道中的生理作用（AIM 4）。我们预计这些研究将提供新的知识，这可能会导致哮喘和其他支气管疾病的新型治疗方法的发展。