Extracellular determinants of airway smooth muscle force: A new paradigm for sust

气道平滑肌力的细胞外决定因素：维持的新范例

• 批准号: 8865673
• 负责人: Harikrishnan Parameswaran
• 金额: $ 11.37万
• 依托单位: BOSTON UNIVERSITY (CHARLES RIVER CAMPUS)
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-04 至 2016-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8865673
• 关键词: Actins; Address; Affect; Agonist; Asthma; Atherosclerosis; Breathing; Cell Culture Techniques; Cell membrane; Cells; Chronic; Computer Simulation; Coupling; Data; Dependence; Disease; Elements; Environment; Equilibrium; Fiber; Generations; Geometry; Human; Hypertension; Image; Individual; Inflammation; Inflammatory; Label; Life; Link; Measurement; Mechanics; Mentors; Microfilaments; Microscopic; Microscopy; Modeling; Molecular; Muscle Contraction; Myosin ATPase; Myosin Type II; Pattern; Phase; Physiology; Play; Prevalence; Process; Property; Protein Isoforms; Recovery; Relative (related person); Research; Research Personnel; Role; Smooth Muscle; Smooth Muscle Myocytes; Stretching; Structure; Structure-Activity Relationship; System; Techniques; Testing; Time; Traction; Training; Vascular Smooth Muscle; airway inflammation; airway remodeling; asthmatic; base; cell type; cellular imaging; constriction; crosslink; extracellular; novel; public health relevance; research study; respiratory smooth muscle; stem

DESCRIPTION (provided by applicant): Asthma is a chronic inflammatory disease that affects over 24 million people in the US and over 300 million people worldwide and its prevalence is rising. It is well recognized by now that chronic inflammation leads to an altered mechanical stiffness and composition of the airways referred to "airway remodeling". Further, changes in airway stiffness implies that, during tidal breathing, airway smooth muscle (ASM) cells will be subjected to an altered pattern of strains. This proposal addresses a critical question: Can the alterations in the mechanics of its extracellular environment drive the ASM cells into an altered baseline state such that upon agonist exposure, it can generate and sustain a force capable of amplified airway constriction? This proposal seeks to answer this question and identify the underlying mechanisms. Within the ASM, the contractile machinery of actin and myosin exists not only in the form of parallel arrays of contractile elements, but also as a very dense layer of actin close to cell membrane with non-muscle isoforms of myosin, referred to as the cortical actin (CA) network. Our central hypothesis is that alterations in the stiffness of the extracellula matrix (ECM) can cause the CA network to actively reorganize into unique configurations capable of sustaining exaggerated force generation by the ASM. This hypothesis derives from a computational model, that we developed, which shows that the ability of the ASM cells to maintain force for long periods of time can be explained by mechanical interactions between parallel array of actin myosin fibers and the CA network. The same model predicts that there are certain regimes of ECM stiffness that can cause the ASM generate very high forces when exposed to agonist. To experimentally verify these ideas, during the mentored phase of this proposal, I will gain training in primary human ASM cell culture, cellular traction force measurement, GFP labeling of actin and other cytoskeletal components and microscopy techniques for live cell imaging. This will be used to experimentally establish the effect of ECM stiffness on baseline and active force that an ASM can generate and determine a link between CA network structure and ASM force. Following this, I hope to transition into an independent investigator. During the R00 phase, I will examine the effect of stretch and deep breathing on cortical actin network geometry and how ASM cells can be driven into high or low force generating regimes using externally imposed strains and finally in aim 3, I will determine how these results scale to a multi-cellular ensemble of ASM cells with specific focus on understanding the effect of stretch and ECM stiffness on the strength of the coupling between ASM cells. Ultimately, this research may derive a new cellular and molecular based paradigm that explains how and why the ASM embedded in a remodeled airway can become hyperreactive and the role that dynamic forces play in sustaining or ablating this condition.

描述（由申请人提供）：哮喘是一种慢性炎症性疾病，影响着美国超过 2400 万人和全球超过 3 亿人，并且其患病率正在上升。现在人们已经充分认识到，慢性炎症会导致气道机械刚度和组成的改变，称为“气道重塑”。此外，气道硬度的变化意味着，在潮式呼吸期间，气道平滑肌（ASM）细胞将受到改变的应变模式的影响。该提案解决了一个关键问题：细胞外环境力学的改变能否驱动 ASM 细胞进入改变的基线状态，以便在暴露于激动剂时，它可以产生并维持能够放大气道收缩的力？该提案旨在回答这个问题并确定根本机制。在 ASM 中，肌动蛋白和肌球蛋白的收缩机制不仅以收缩元件平行阵列的形式存在，而且还作为靠近细胞膜的非常致密的肌动蛋白层和非肌肉肌球蛋白亚型存在，称为皮质肌动蛋白（CA）网络。我们的中心假设是，细胞外基质 (ECM) 硬度的改变可以导致 CA 网络主动重组为独特的配置，能够维持 ASM 产生的夸张的力。这一假设源自我们开发的计算模型，该模型表明 ASM 细胞长时间维持力的能力可以通过肌动蛋白纤维平行阵列与 CA 网络之间的机械相互作用来解释。同一模型预测，某些 ECM 刚度状态可能会导致 ASM 在暴露于激动剂时产生非常高的力。为了通过实验验证这些想法，在本提案的指导阶段，我将接受原代人类 ASM 细胞培养、细胞牵引力测量、肌动蛋白和其他细胞骨架成分的 GFP 标记以及活细胞成像显微镜技术方面的培训。这将用于通过实验确定 ECM 刚度对 ASM 生成的基线和主动力的影响，并确定 CA 网络结构和 ASM 力之间的联系。在此之后，我希望转型为一名独立调查员。在 R00 阶段，我将研究拉伸和深呼吸对皮质肌动蛋白网络几何形状的影响，以及如何使用外部施加的应变将 ASM 细胞驱动到高或低力生成状态，最后在目标 3 中，我将确定如何将这些结果扩展到 ASM 细胞的多细胞集合，特别关注了解拉伸和 ECM 刚度对 ASM 细胞之间耦合强度的影响。最终，这项研究可能会得出一种新的基于细胞和分子的范式，解释嵌入重塑气道的 ASM 如何以及为何变得过度反应，以及动态力在维持或消除这种情况中所发挥的作用。

项目成果

Stiffening of the extracellular matrix is a sufficient condition for airway hyperreactivity.

细胞外基质的硬化是气道高反应性的充分条件。

• DOI: 10.1152/japplphysiol.00554.2020
• 发表时间: 2021
• 期刊: Journal of applied physiology (Bethesda, Md. : 1985)
• 作者: Jamieson,RyanR;Stasiak,SuzanneE;Polio,SamuelR;Augspurg,RalstonD;McCormick,CarolineA;Ruberti,JeffreyW;Parameswaran,Harikrishnan
• 通讯作者: Parameswaran,Harikrishnan

Can breathing-like pressure oscillations reverse or prevent narrowing of small intact airways?

类似呼吸的压力波动能否逆转或防止完整的小气道变窄？

• DOI: 10.1152/japplphysiol.01100.2014
• 发表时间: 2015
• 期刊: Journal of applied physiology (Bethesda, Md. : 1985)
• 作者: Harvey,BrianC;Parameswaran,Harikrishnan;Lutchen,KennethR
• 通讯作者: Lutchen,KennethR