Contributions of vascular chemokine receptors to cardiovascular function after traumatic-hemorrhagic shock

项目摘要/摘要 血管张力丧失是失血性休克和液体中心血管衰竭的特征 复苏(HS/R)。α1肾上腺素能受体(ARs)的功能障碍和脱敏被认为是 血管扩张性休克的发展特征。α1-AR功能障碍的机制有 未知。趋化因子(C-C基序)趋化因子配体2(CCL2)、CCL3、CCL5和CCL22 被确定为HS/R初始炎症反应的关键驱动因素，以及分离的早期生物标志物 幸存和非幸存的创伤患者。潜在的病理生理和分子机制 然而，这些重要的临床相关性仍有待确定。我们发现趋化因子 受体(CRS)(C-C基序)趋化因子受体1(CCR1)、CCR2和CCR4是CCL2的受体， CCl_3、CCl_5和CCl_(22)与α_1-AR在阻力动脉中膜形成异构体复合体。 我们提供了激活CCR2拮抗α1-AR介导的血管收缩的初步证据 阻力动脉和交叉招募b-arrestin到α1-AR，一个分子信号事件，启动清除 α1-AR来自质膜。这导致了我们的主要假设，趋化因子在早期释放 HS/R时相通过激活CRS损害血管张力和血压调节， α1-AR与血管平滑肌细胞(VSMC)的相互作用和调节。这意味着药理上的 靶向与α1-AR相互作用的CRs将提供新的治疗选择，以稳定血管张力和 血液动力学，防止心血管衰竭，改善HS后的复苏。为了检验这一假设， 我们提出了三个具体的目标：1)确定α1-AR的CR异构化伙伴是如何调节的 体外血管功能。我们将使用分离阻力动脉的压力肌成像术作为测试。 确定已识别的CR异构化伙伴在调节内在血管中的作用的平台 功能和血管升压反应性。2)测试CR的药理学靶向性 α1-AR的异构化伙伴在体内调节心血管功能。我们将决定如何 阻断和激活CR异构化伙伴影响正常的心血管功能和血管加压素 HS/R期间的反应性和心血管功能3)通过以下方式确定分子机制 α1-AR的CR异构化伙伴调节α1-AR的功能。我们将确定 已鉴定的CRS和α1-AR之间的串扰机制，并阐明CR α1-AR的异构化伙伴调控α1-AR诱导的信号转导和VSMC收缩。新知识 这一建议将促进我们对血管功能调节的理解，并确定 新的分子靶点可用于改善HS/R期间的血压控制，以及 一般情况下，血液动力学不稳定的危重患者。

Project Summary/Abstract Loss of vascular tone is characteristic for cardiovascular collapse during hemorrhagic shock and fluid resuscitation (HS/R). Dysfunction and desensitization of α1-adrenergic receptors (ARs) is considered the hallmark in the development of vasodilatory shock. The mechanisms responsible for α1-AR dysfunction are unknown. The chemokines (C-C motif) chemokine ligand 2 (CCL2), CCL3, CCL5 and CCL22 have been identified as key drivers of the initial inflammatory response to HS/R, and as early biomarkers that segregate surviving and non-surviving trauma patients. The pathophysiological and molecular mechanisms underlying these important clinical correlations, however, remain to be determined. We discovered that the chemokine receptors (CRs) (C-C motif) chemokine receptor 1 (CCR1), CCR2 and CCR4, which are receptors for CCL2, CCL3, CCL5 and CCL22, form heteromeric complexes with α1-AR in the tunica media of resistance arteries. We provide preliminary evidence that activation of CCR2 antagonizes α1-AR mediated constriction of isolated resistance arteries and cross-recruits b-arrestin to α1-AR, a molecular signaling event that initiates removal of α1-AR from the plasma membrane. This leads to our main hypothesis that chemokine release during early phases of HS/R impairs vascular tone and blood pressure regulation through activation of their CRs, which interact with and regulate α1-AR in vascular smooth muscle cells (VSMCs). This implies that pharmacological targeting of the CRs that interact with α1-AR will provide new therapeutic options to stabilize vascular tone and hemodynamics, prevent cardiovascular collapse and improve resuscitation after HS. To test this hypothesis, we propose three specific aims: 1) To determine how the CR heteromerization partners of α1-AR regulate vascular function ex vivo. We will utilize pressure myography with isolated resistance arteries as a test platform to define the roles of the identified CR heteromerization partners in the regulation of intrinsic vascular function and vasopressor responsiveness. 2) To test how pharmacological targeting of the CR heteromerization partners of α1-AR modulates cardiovascular function in vivo. We will determine how blockade and activation of CR heteromerization partners affect normal cardiovascular function, vasopressor responsiveness and cardiovascular function during HS/R. 3) To determine the molecular mechanisms by which the CR heteromerization partners of α1-AR regulate α1-AR function. We will determine the mechanisms of cross-talk between the identified CRs and α1-AR, and elucidate the pathways by which the CR heteromerization partners of α1-AR modulate α1-AR-induced signaling and VSMC contraction. New knowledge gained from this proposal will advance our understanding of the regulation of vascular function and identify new molecular targets that could be used to improve blood pressure control during HS/R, and in hemodynamically instable critically ill patients in general.