MECHANISMS OF DEFORMATION-INDUCED ATP RELEASE FROM RBCS

变形诱导的红细胞 ATP 释放机制

• 批准号: 6192277
• 负责人: RANDY SPRAGUE
• 金额: $ 25.9万
• 依托单位: SAINT LOUIS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-08-15 至 2004-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6192277
• 关键词: G protein; adenosine triphosphate; animal tissue; biological signal transduction; clinical research; cyclic AMP; erythrocytes; hemodynamics; human subject; laboratory rabbit; mechanical stress; microcirculation; protein kinase A; pulmonary circulation; pulmonary hypertension; vascular resistance

When traversing microvascular beds, such as in the lung, red blood cells (RBCs) are subjected to mechanical deformation. Our previous findings that RBCs are required for flow-induced nitric oxide (NO) synthesis in the lung and that mechanical deformation of RBCs results in the release of adenosine triphosphate (ATP), a stimulus for endothelial NO synthesis, suggested a novel mechanism for the control of vascular resistance in the pulmonary circulation. In this construct, as the RBC is increasingly deformed by increments in the velocity of blood flow through a vessel and/or by reductions in vascular caliber, it releases ATP which stimulates the synthesis of NO resulting in relaxation of vascular smooth muscle and, thereby, an increase in vascular caliber. We propose that RBC-derived ATP contributes to the low vascular resistance of the healthy lung. Moreover, if deformation-induced ATP release from RBCs is an important determinant of vascular resistance in the lung, then a signal- transduction pathway for ATP release in response to this stimulus should be present in that cell. Here, we address the hypothesis that mechanical deformation of RBCs sets into motion specific signal transduction pathways which culminate in release of adenosine triphosphate (ATP). In this proposal we intend to 1) demonstrate that heterotrimeric G proteins are components of a signal transduction pathway for deformation-induced release of ATP from RBCs of rabbits and healthy humans, 2) establish that increases in intracellular cAMP are required for deformation- induced ATP release from these RBCs, 3) demonstrate that the activity of protein kinase A (PKA) is required for deformation- induced ATP release from RBCs of rabbits and healthy humans, 4) establish that ATP release from these RBCs requires the activity of the nucleoside transporter and 5) establish that deformation- induced ATP release from RBCs is decreased in humans with primary pulmonary hypertension and determine the associated defect(s) in the signal-transduction pathway for ATP release in these patients. The successful completion of the studies described in this proposal will define a new role for the RBC as a regulator of vascular resistance in the pulmonary circulation and may provide new insights into the pathophysiology of pulmonary hypertension. This hypothesis is the logical extension of our previous work and is consistent with a major focus of this group, namely, identification and characterization of those mechanisms responsible for the control of pulmonary vascular resistance.

当穿越微血管床（例如在肺中）时，红细胞（RBC）会经过机械变形。 我们先前的发现，RBC是肺中流动诱导的一氧化物（NO）合成所必需的，而RBC的机械变形导致释放三磷酸腺苷（ATP），这是一种内皮NO合成的刺激，提示了在肺部循环中控制血管抗性的新型机制。 在这种构建体中，由于RBC越来越多地通过血液流动的速度和/或血管口径减少而逐渐变形，因此它释放出ATP，从而刺激了无需刺激血管平滑肌的合成，从而刺激了血管平滑肌的放松，从而刺激了血管温度的增加。 我们建议，RBC衍生的ATP有助于健康肺的低血管耐药性。 此外，如果变形引起的ATP从RBCS释放是肺中血管抗性的重要决定因素，则应在该细胞中存在信号转导途径以响应于该刺激的ATP释放。 在这里，我们解决了以下假设：RBC的机械变形设置为运动特异性信号转导途径，这些途径在释放三磷酸腺苷（ATP）时达到最终形式。 在这项提案中，我们打算1）证明异三个蛋白是信号转导途径的组成部分，用于变形引起的ATP从兔子和健康人的RBC中释放出ATP的释放，2）确定细胞内cAMP的增加是在这些RBC中释放出ATP的prove of Prote of Prote of proce a prote of proce of proce of proce a proce of proce of proce of proce a proce of proce a protem provement of proce a prote a protive aive ai的活动a（proce）a（proce）a provem-从兔子和健康人的RBC中释放的ATP释放，4）确定从这些RBC中释放的ATP需要核苷转运蛋白的活性，5）5）确定，与原发性肺部高位的人相关的人体中，RBC释放的ATP释放降低，并确定相关的相关缺陷（S）在signal-Transd pertenawe perage for sp perage for asp perage for astp perage inp aTP中的释放。 该提案中描述的研究的成功完成将定义RBC作为肺循环中血管抗性的调节剂的新作用，并可能为肺动脉高压的病理生理学提供新的见解。 该假设是我们先前工作的逻辑扩展，并且与该组的主要重点是一致的，即对控制肺血管抗性控制的那些机制的识别和表征。