KCNQ Channels in Airway Smooth Muscle Physiology and Disease

KCNQ 气道平滑肌生理学和疾病中的通道

• 批准号: 9210531
• 负责人: KENNETH L BYRON
• 金额: --
• 依托单位: EDWARD HINES JR VA HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9210531
• 关键词: Abbreviations; Acetates; Acetylcholine; Address; Affect; Agonist; Airway Resistance; Animal Model; Area; Asthma; Attenuated; Biochemical; Biological; Biophysical Process; Bronchioles; Bronchoconstriction; Bronchoconstrictor Agents; Bronchodilator Agents; Caliber; Cavia; Chronic; Clinical; Coupled; Development; Diagnosis; Disease; Drug Targeting; Electrophysiology (science); Elements; Endothelin-1; Etiology; Family; Functional disorder; Gene Family; Genetic Transcription; Histamine; Human; Inflammation Mediators; Interleukin-1 beta; Interleukin-13; Leukotriene D4; Link; Lung; Lung diseases; Measurement; Measures; Membrane; MicroRNAs; Mission; Molecular; Muscle Cells; Muscle Contraction; Muscle function; Myopathy; Obstructive Lung Diseases; Outcome; Ovalbumin; Pharmaceutical Preparations; Pharmacology; Physiology; Play; Population; Potassium; Potassium Channel; Protein Kinase C; Receptor Activation; Recruitment Activity; Regulation; Research; Research Support; Role; Slice; Stimulus; Structure of parenchyma of lung; Symptoms; Testing; Therapeutic; Tissues; Veterans; airway hyperresponsiveness; airway inflammation; airway obstruction; asthmatic; asthmatic airway; asthmatic patient; base; beta-2 Adrenergic Receptors; cohort; constriction; fundamental research; gene repression; improved; in vivo; innovation; methacholine; muscle physiology; novel; novel therapeutic intervention; novel therapeutics; patch clamp; phorbol-12-myristate; preclinical study; prevent; public health relevance; receptor; reduce symptoms; research and development; respiratory smooth muscle; response; sensitizing antigen; transcription factor; translational medicine; voltage

 DESCRIPTION (provided by applicant) Asthma is a chronic respiratory disease characterized by reversible airway obstruction and hyper- responsiveness of the airways to bronchoconstrictor stimuli. Veterans represent a large cohort of asthma sufferers, many of whom do not achieve relief of symptoms with available therapies. Reversible airway obstruction in asthma results primarily from hypercontraction of airway smooth muscle cells (ASMCs) in the bronchioles of the lung. The mechanisms involved in ASMC hypercontraction are poorly characterized but likely involve exaggerated bronchoconstrictor responses to Gq/11-coupled receptor agonists, which include acetylcholine, histamine, endothelin-1, and leukotriene D4. Increased Ca2+ influx via voltage-sensitive Ca2+ channels (VSCCs) contributes to the exaggerated bronchoconstrictor responses. The voltage change required to activate VSCCs can be provided by suppressing potassium (K+) channel activity. We recently discovered that KCNQ (Kv7 family) K+ channels are expressed and active in freshly isolated bronchiolar myocytes and that their activity is suppressed by multiple bronchoconstrictor agonists. We further demonstrated that Kv7 current suppression is sufficient to induce airway constriction and that pharmacological Kv7 channel activators significantly attenuate airway constriction in precision-cut human lung slices. Based on these discoveries, we propose to examine the hypothesis that bronchoconstrictor agonists suppress the activity of Kv7 family K+ channels in ASMCs to induce membrane depolarization and ASMC hypercontraction. Furthermore, we will explore two additional hypotheses that have important clinical/translational relevance for our understanding and treatment of asthma. We hypothesize that inflammatory mediators alter Kv7 channel expression, which plays a role in the etiology of airway hyperresponsiveness in asthma. Furthermore, because Kv7 channels are established drug targets, we hypothesize that clinically used Kv7 channel activators can be used as a monotherapy or they may be combined with other therapies to prevent or reduce excessive airway constriction in asthma. To address our hypotheses, three Specific Aims are proposed. Aim 1) Elucidate the mechanisms by which Gq/11-coupled receptor agonists regulate Kv7 currents in ASMCs. The role of protein kinase C will be determined by using a variety of biochemical, pharmacological, and molecular biological approaches in combination with patch clamp electrophysiology and measurements of airway smooth muscle function in human and guinea pig ASMCs and lung tissues. Aim 2) Test two novel hypotheses linking airway inflammation to suppression of Kv7 channel expression in ASMCs and increased sensitivity to bronchoconstrictor stimuli. Hypothesis 1: inflammatory mediators, such as IL-13 and IL-1β, upregulate repressor element 1 silencing transcription factor (REST), which then inhibits transcription of KCNQ genes in ASMCs. Hypothesis 2: micro RNA 146a (miR146a), which is also increased in response to inflammatory mediators, induces post- transcriptional repression of Kv7.5 expression in ASMCs. REST and miR146a expression will be measured/altered in ASMCs from normal and asthmatic human and guinea pig lungs to determine their relationship to altered expression/function of Kv7 channels and the link to airway hyperresponsiveness. Aim 3) Evaluate the therapeutic benefits of Kv7 channel activators, alone or combined with β2-adrenergic receptor agonists, on airway function in vivo in normal and antigen-sensitized guinea pigs. Our proposed studies are significant because they will elucidate previously unknown mechanisms for ASMC hypercontraction and identify a new therapeutic strategy to provide better relief of airway hyperresponsiveness in asthma patients. This outcome would directly benefit thousands of veterans and civilians who suffer from asthma or other airway diseases.

 描述（由申请人提供） 哮喘是一种慢性呼吸道疾病，其特征是可逆性气道阻塞和气道对支气管收缩刺激的过度反应。退伍军人是一大群哮喘患者，他们中的许多人无法通过现有的治疗来缓解可逆性气道阻塞的症状。主要来自肺细支气管中气道平滑肌细胞 (ASMC) 的过度收缩。ASMC 过度收缩所涉及的机制尚不清楚，但可能涉及夸大的内容。支气管收缩剂对 Gq/11 偶联受体激动剂（包括乙酰胆碱、组胺、内皮素-1 和白三烯 D4）的反应。通过电压敏感 Ca2+ 通道 (VSCC) 增加的 Ca2+ 流入会导致支气管收缩剂反应过度。 VSCC 可以通过抑制钾 (K+) 通道活性来提供。我们最近发现 KCNQ。 （Kv7 家族）K+ 通道在新鲜分离的细支气管肌细胞中表达并活跃，并且其活性被多种支气管收缩剂激动剂抑制。我们进一步证明 Kv7 电流抑制足以诱导气道收缩，并且药理学 Kv7 通道激活剂可显着减弱气道收缩。基于这些发现，我们建议检验支气管收缩剂激动剂抑制支气管收缩剂活性的假设。 ASMC 中的 Kv7 家族 K+ 通道可诱导膜去极化和 ASMC 过度收缩，此外，我们将探索两个对我们理解和治疗哮喘具有重要临床/转化相关性的假设。此外，由于 Kv7 通道是既定的药物靶点，我们探索了临床使用的 Kv7 通道激活剂可用作单一疗法。或者它们可以与其他疗法相结合，以预防或减少哮喘中的过度气道收缩。为了解决我们的假设，提出了三个具体目标：1) 阐明 Gq/11 偶联受体激动剂调节 ASMC 中 Kv7 电流的机制。蛋白激酶 C 的作用将通过使用各种生化、药理学和分子生物学方法，结合膜片钳电生理学以及人类和豚鼠气道平滑肌功能的测量来确定ASMC 和肺组织。测试两个新假设，将气道炎症与 ASMC 中 Kv7 通道表达抑制和支气管收缩剂刺激敏感性增加联系起来。假设 1：炎症介质（例如 IL-13 和 IL-1β）上调阻遏元件 1。沉默转录因子 (REST)，然后抑制 ASMC 中 KCNQ 基因的转录。 假设 2：微小 RNA 146a。 (miR146a) 也会因炎症介质而增加，诱导 ASMC 中 Kv7.5 表达的转录后抑制，并且将在正常和哮喘人和豚鼠肺的 ASMC 中测量/改变 miR146a 表达，以确定它们的表达。与 Kv7 通道表达/功能改变的关系以及与气道高反应性的联系 目标 3) 评估 Kv7 的治疗益处。通道激活剂单独或与β2-肾上腺素能受体激动剂联合使用，对正常和抗原敏感豚鼠体内气道功能的影响，我们提出的研究具有重要意义，因为它们将阐明以前未知的 ASMC 过度收缩机制，并确定一种新的治疗策略。更好地缓解哮喘患者的气道高反应性将直接使成千上万患有哮喘或其他气道疾病的退伍军人和平民受益。