Airway muscle tone, RhoA & Cytoskeletal remodeling

气道肌张力，RhoA

• 批准号: 6931671
• 负责人: CAROL A HIRSHMAN
• 金额: $ 32.7万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-01 至 2008-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6931671
• 关键词: ADP ribosylation; G protein; actins; antisense nucleic acid; beta adrenergic agent; beta adrenergic receptor; biological signal transduction; bronchomotion; calcium flux; cytoskeleton; fluorescence microscopy; guanine nucleotide binding protein; guinea pigs; immunofluorescence technique; muscle contraction; paxillin; polymerase chain reaction; protein kinase A; protein tyrosine kinase; receptor coupling; receptor expression; respiratory pharmacology; smooth muscle; stimulant /agonist; tissue /cell culture; transfection

DESCRIPTION (provided by applicant): Although B2-adrenergic agonists are widely used for the acute treatment for asthma, these therapeutic agents are not ideal. They are not always effective in severe asthma, must be redosed frequently, are often inadequate as sole therapy and are associated with increased mortality. B2 agonists are thought to reduce symptoms of asthma by directly relaxing airway smooth muscle via the Gs/cAMP- PKA pathway but the events downstream from PKA are not known. Although PKA-independent mechanisms have been suggested, the signaling intermediates in a PKA-independent pathway have never been identified. Exciting preliminary data demonstrate B-adrenergic agonist-mediated relaxation of intact airway smooth muscle and actin deploymerization of primary cultures of human airway smooth muscle cells via a novel PKA-independent signaling pathway involving Src tyrosine kinases as well as by PKA-dependent inhibition of RhoA. RhoA is a monomeric G proteins that plays a central role in the dynamic regulation of the actin cytoskeleton in airway smooth muscle cells and in maintaining contraction in intact smooth muscle. We now seek to identify the intermediates in the PKA-independent pathway and to determine whether the PKA-dependent and/or PKA-independent signaling involve inhibition of RhoA. We hypothesize that B-adrenergic agonists induce airway smooth muscle relaxation and actin depolymerization by a novel PKA-independent pathway that involves Gs activation of Lck tyrosine kinase with subsequent activation of P190 RhoGAP leading to RhoA inhibition as well as by PKA-dependent inhibition of RhoA and dephosphorylation of cofilin. We propose: to confirm preliminary data demonstrating that B-adrenergic agonists inhibit contraction of intact airway smooth muscle by PKA-independent as well as by PKA-dependent mechanisms and to identify intermediates involved (Aim 1); to identify the Src tyrosine kinase involved in the PKA-independent pathway and explore the upstream (Gs protein) and downstream (P190 RhoGAP) intermediates (Aim 2); and to determine if B-adrenergic agonists induce actin depolymerization by PKA-induced phosphorylation and inhibition of RhoA; (Aim 3). Identification of intermediates of a signaling pathway that relaxes airway smooth muscle in a PKA-independent manner would provide new selective targets for asthma drug therapy and would be a significant advance in the field. Identifying novel pathways in airway smooth muscle that mediate relaxation will lead to new therapeutic intervention strategies that may be employed to impair the ability of airway smooth muscle to contract and cause acute airway narrowing in asthma.

描述（由申请人提供）：尽管B2-肾上腺素能激动剂被广泛用于哮喘的急性治疗，但这些治疗剂并不理想。它们在严重的哮喘中并不总是有效的，必须经常施加，通常是唯一治疗的不足，并且与死亡率增加有关。 B2激动剂被认为可以通过GS/Camp- PKA途径直接放松气道平滑肌来减少哮喘的症状，但PKA下游的事件尚不清楚。尽管已经提出了非依赖性PKA的机制，但从未鉴定出独立于PKA的途径中的信号传导中间体。令人兴奋的初步数据表明，B-肾上腺素激动剂介导的完整气道平滑肌的松弛和肌动蛋白通过涉及SRC酪氨酸激酶以及PKA依赖性依赖性RhoA的新型PKA光滑肌肉细胞的原发性培养物对人类气道平滑肌细胞的原发性培养。 RhoA是一种单体G蛋白，在气道平滑肌细胞中肌动蛋白细胞骨架的动态调节中起着核心作用，并在完整的平滑肌中保持收缩。现在，我们试图在非依赖PKA的途径中识别中间体，并确定PKA依赖性和/或非独立信号是否涉及抑制RhoA。 We hypothesize that B-adrenergic agonists induce airway smooth muscle relaxation and actin depolymerization by a novel PKA-independent pathway that involves Gs activation of Lck tyrosine kinase with subsequent activation of P190 RhoGAP leading to RhoA inhibition as well as by PKA-dependent inhibition of RhoA and dephosphorylation of cofilin.我们提出：确认初步数据，以表明B-肾上腺素能激动剂抑制PKA独立和PKA依赖性机制的完整气道平滑肌的收缩，并识别涉及的中间体（AIM 1）；确定与PKA独立途径有关的SRC酪氨酸激酶，并探索上游（GS蛋白）和下游（P190 RhoGap）中间体（AIM 2）；并确定B-肾上腺素能激动剂是否通过PKA诱导的磷酸化和抑制RhoA诱导肌动蛋白解聚； （目标3）。以非独立的方式鉴定信号通路的中间体，该信号传导途径会为哮喘药物治疗提供新的选择性目标，并将在该领域提供重大进步。在气道平滑肌中识别介导放松的新型途径将导致新的治疗干预策略，这些干预策略可能会损害气道平滑肌收缩和导致哮喘中急性气道变窄的能力。