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系统疾病，其特征是可逆性气道阻塞和气道对支气管收缩刺激的高反应性。退伍军人代表了一个庞大的哮喘患者群体，其中许多人没有达到缓解症状与现有的治疗。哮喘的可逆性气道阻塞主要由肺细支气管中气道平滑肌细胞（ASMC）的过度收缩引起。ASMC过度收缩的机制尚不清楚，但可能涉及对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）的过度支气管收缩反应。通过电压敏感性Ca 2+通道（VSCC）增加的Ca 2+内流有助于放大的支气管收缩反应。激活VSCC所需的电压变化可以通过抑制钾（K+）通道活性来提供。我们最近发现KCNQ（Kv 7家族）K+通道在新鲜分离的细支气管肌细胞中表达和活跃，并且它们的活性被多种支气管收缩剂激动剂抑制。我们进一步证明了Kv 7电流抑制足以诱导气道收缩，并且药理学Kv 7通道激活剂显著减弱精确切割的人肺切片中的气道收缩。基于这些发现，我们建议检查支气管收缩剂激动剂抑制ASMCs中Kv 7家族K+通道的活性以诱导膜去极化和ASMC过度收缩的假设。此外，我们还将探讨另外两个对我们理解和治疗哮喘具有重要临床/翻译相关性的假设。我们假设炎症介质改变Kv 7通道的表达，这在哮喘气道高反应性的病因学中起作用。此外，由于Kv 7通道是确定的药物靶点，我们假设临床上使用的Kv 7通道激活剂可以作为单一疗法使用，或者可以与其他疗法联合使用，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。目的1）阐明Gq/11偶联受体激动剂对ASMCs Kv 7电流的调控机制。蛋白激酶C的作用将通过使用多种生物化学、药理学和分子生物学方法结合膜片钳电生理学和测量人和豚鼠ASMC和肺组织中的气道平滑肌功能来确定。目的2）验证两个新的假设，即气道炎症与ASMCs中Kv 7通道表达的抑制以及对支气管收缩刺激的敏感性增加有关。假设1：炎性介质如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。假设二：微小RNA 146 a（miR 146 a）也响应于炎症介质而增加，其诱导ASMC中Kv7.5表达的转录后抑制。将在来自正常和哮喘人和豚鼠肺的ASMC中测量/改变REST和miR 146 a表达，以确定它们与Kv 7通道的改变的表达/功能的关系以及与气道高反应性的联系。目的3）评价Kv 7通道激动剂单独或与β2-肾上腺素能受体激动剂联合应用对正常和抗原致敏豚鼠气道功能的治疗作用。我们提出的研究是重要的，因为他们将阐明以前未知的机制ASMC过度收缩，并确定一个新的治疗策略，以提供更好的缓解哮喘患者的气道高反应性。这一结果将直接惠及数千名患有哮喘或其他气道疾病的退伍军人和平民。