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

基本信息

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
项目类别：
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

项目摘要

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.

项目概要：使血流和氧气输送与组织需氧量相匹配是最重要的基础之一生理过程。最近的研究表明，红细胞（RBC）感知缺氧并通过以下方式做出反应：释放ATP。红细胞衍生的 ATP 会引起血管舒张，从而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实验室已经证明红细胞健康老年人以及 II 型糖尿病和肺结核患者的 ATP 释放受损高血压。目前研究缺氧引起的红细胞 ATP 释放的方法仅限于静态测量不同氧合水平 (PO2) 下的 ATP，因此是理解缺氧诱导的关键障碍 RBC ATP 释放无法同时实时测量 PO2 和 ATP 释放。我们的初步数据表明，镁绿 (Mg-G) 荧光血氧测定法可以同时测量 ATP 释放和实时 PO2，可以精确量化 RBC 功能的变量，包括总 ATP 释放，启动 ATP 释放所需的 PO2、ATP 释放峰值速率等。虽然已经很完善了缺氧期间调节 ATP 释放的最终通道是通过 pannexin-1 通道发生的，响应缺氧刺激红细胞 ATP 释放的机制仍不清楚。红细胞变形能力与缺氧诱导的 ATP 释放有关，我们已经证明，改善老年人的红细胞恢复 ATP 释放。最近的数据表明机械活化的阳离子通道 Piezo1 在剪切介导的红细胞 ATP 释放中的作用，然而 Piezo1 在缺氧诱导的红细胞 ATP 中的作用释放情况未知。因此，这个探索性研究计划的总体目标是建立我们新颖的同时监测实时红细胞 ATP 释放和 PO2 的方法，并探索 Piezo1 的作用刺激年轻人和老年人缺氧期间 ATP 的释放。在具体目标 1.1 和 1.2 中，我们将使用连续、同时测量 PO2 和 ATP，以确定红细胞 ATP 释放过程中的参数进行性缺氧。我们将通过证明缺氧期间 ATP 释放被废除来验证我们的方法通过 pannexin-1 通道阻断。在具体目标 2.1 和 2.2 中，我们将确定是否刺激 Piezo1 通道对于年轻人缺氧诱导的红细胞 ATP 释放是必需的，以及是否减少 Piezo1 通道的刺激解释了老年人红细胞 ATP 释放受损的原因。我们还将确定机械敏感 Piezo1 通道的药理刺激是否可以逆转年龄相关的红细胞 ATP 释放受损。拟议研究的结果将建立一种新方法研究缺氧期间红细胞的生理学，并将提供有关缺氧机制作用的第一个数据 Piezo1 在缺氧诱导的年轻人和老年人红细胞 ATP 释放中的作用。我们的结果可能会成为推动未来的研究旨在改善老年人和各种患有此病的患者群体的循环 ATP 由于局部血流和氧气输送调节受损而导致运动不耐受或组织缺血。