A novel approach to study mechanisms of age-related dysfunction in hypoxia-induced erythrocyte ATP release

一种研究缺氧引起的红细胞 ATP 释放中年龄相关功能障碍机制的新方法

• 批准号: 10707876
• 负责人: Daniel Lark
• 金额: $ 22.2万
• 依托单位: COLORADO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-30 至 2025-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10707876
• 关键词: Acute; Aging; Binding; Biological; Blood Vessels; Blood flow; Cardiovascular system; Cations; Cell Respiration; Cell physiology; Characteristics; Chronic; Clinical Trials; Data; Diabetes Mellitus; Disease; Elderly; Endothelium; Erythrocytes; Event; Functional disorder; Future; Geroscience; Goals; Heart failure; Hemoglobin; Human; Hypertension; Hypoxia; Impairment; Individual; Intervention Studies; Ischemia; Knockout Mice; Knowledge; Laboratories; Link; Magnesium; Measurement; Measures; Mechanics; Mediating; Methodology; Non-Insulin-Dependent Diabetes Mellitus; Oxygen; Oxygen saturation measurement; Patients; Pharmaceutical Preparations; Physiological; Physiological Processes; Physiology; Piezo 1 ion channel; Populations at Risk; Pulmonary Hypertension; Regional Blood Flow; Regulation; Research Design; Research Proposals; Rodent; Role; Stimulus; Testing; Time; Tissues; Transgenic Organisms; Vasodilation; Work; age related; aged; design; exercise intolerance; experience; human disease; improved; novel; novel diagnostics; novel strategies; novel therapeutic intervention; patient population; pharmacologic; preclinical study; real time monitoring; receptor; response; sensor; therapeutic target; translational study; young adult

PROJECT SUMMARY: Matching blood flow and oxygen delivery to tissue oxygen demand is one of the most essential fundamental physiological processes. Recent studies show that red blood cells (RBCs) sense hypoxia and respond by releasing ATP. RBC-derived ATP causes vasodilation that improves local blood flow and oxygen delivery via binding to endothelial purinergic (P2) receptors. Our laboratory and others have demonstrated that RBC ATP release is impaired in healthy older adults, as well as patients with type II diabetes and pulmonary hypertension. Current methodology to study hypoxia-induced RBC ATP release is limited to static measures of ATP at discrete levels of oxygenation (PO2), and thus the critical barrier to understanding hypoxia-induced RBC ATP release is the inability to simultaneously measure PO2 and ATP release in real-time. Our preliminary data indicates that fluo-oximetry with magnesium green (Mg-G) can simultaneously measure ATP release and PO2 in real-time, allowing for precise quantification of variables of RBC function that include total ATP release, the PO2 required to initiate ATP release, peak rate of ATP release, and others. Although it is well established that the final conduit for regulated ATP release during hypoxia occurs via pannexin-1 channels, the mechanisms stimulating RBC ATP release in response to hypoxia remain unclear. RBC deformability has been linked with hypoxia-induced ATP release, and we have demonstrated that improving deformability of RBCs from older adults restores ATP release. Recent data implicate the mechanically activated cation channel Piezo1 in shear-mediated RBC ATP release, however the role of Piezo1 in hypoxia-induced RBC ATP release is unknown. Therefore, the overall goal of this exploratory research proposal is to establish our novel approach for monitoring real-time RBC ATP release and PO2 simultaneously, and to explore the role of Piezo1 in stimulating ATP release during hypoxia in young and older adults. In Specific Aims 1.1 and 1.2, we will use continuous, simultaneous measurement of PO2 and ATP to define parameters of RBC ATP release during progressive hypoxia. We will validate our approach by demonstrating ATP release during hypoxia is abolished via pannexin-1 channel blockade. In Specific Aims 2.1 and 2.2, we will determine whether stimulation of Piezo1 channels is requisite for hypoxia-induced RBC ATP release in young adults, and whether reduced stimulation of Piezo1 channels explains the impairment in RBC ATP release in older adults. We will also determine whether pharmacological stimulation of mechanosensitive Piezo1 channels reverses the age-related impairment in RBC ATP release. The findings from the proposed studies will establish a novel approach for studying RBC physiology during hypoxia, and will provide the first data regarding the mechanistic role of Piezo1 in hypoxia-induced RBC ATP release in young and older adults. Our results could be the impetus for future studies designed to improve circulating ATP in older adults and various patient populations suffering from exercise intolerance or tissue ischemia due to impaired local regulation of blood flow and oxygen delivery.

项目摘要： 将血流和氧气递送到组织氧的需求是最重要的基本之一 生理过程。最近的研究表明，红细胞（RBC）感知缺氧，并通过 释放ATP。 RBC衍生的ATP导致血管舒张改善局部血流和氧气输送 通过与内皮嘌呤能（P2）受体结合。我们的实验室和其他人证明了RBC 健康的老年人以及II型糖尿病和肺部患者的ATP释放受损 高血压。当前研究缺氧引起的RBC ATP释放的方法仅限于静态测量 ATP在离散的氧合水平（PO2）中，因此了解缺氧诱导的关键障碍 RBC ATP释放是无法实时测量PO2和ATP释放的。我们的初步 数据表明用镁绿色（MG-G）同时测量ATP释放，并且 实时PO2，允许精确量化RBC函数的变量，其中包括总ATP释放， 启动ATP释放，ATP释放的峰值速率等所需的PO2。虽然已经建立了 在缺氧期间受调节的ATP释放的最终导管通过pannexin-1通道发生， 刺激RBC ATP释放响应缺氧的机制尚不清楚。 RBC可变形性具有 与缺氧引起的ATP释放有关，我们已经证明 来自老年人的RBC恢复了ATP的释放。最近的数据暗示了机械激活的阳离子 剪切介导的RBC ATP释放中的通道压电1，但是压电1在低氧诱导的RBC ATP中的作用 释放是未知的。因此，这项探索性研究建议的总体目标是建立我们的小说 同时监视实时RBC ATP发布和PO2的方法，并探索Piezo1的作用 在年轻人和老年人中刺激缺氧期间的ATP释放中。在特定的目标1.1和1.2中，我们将使用 连续的，同时测量PO2和ATP，以定义RBC ATP释放的参数 进行性缺氧。我们将通过证明在缺氧期间的ATP释放来验证我们的方法 通过pannexin-1通道阻滞。在特定目标2.1和2.2中，我们将确定是否刺激 压电通道是低氧诱导的年轻人RBC ATP释放的必要条件，以及是否减少 压电1通道的刺激解释了老年人RBC ATP释放的损害。我们也会 确定机械敏感的Piezo1通道的药理刺激是否逆转与年龄相关的 RBC ATP发行中的损害。拟议研究的发现将建立一种新颖的方法 在缺氧期间研究RBC生理学，并将提供有关机械作用的第一个数据 在低氧诱导的年轻人和老年人中诱导的RBC ATP释放中。我们的结果可能是 未来的研究旨在改善老年人和各种患者人群的循环ATP 由于局部调节血流和氧递送的局部调节而导致的运动不耐受或组织缺血。