Physiologic, ventilatory, and CNS transcriptomic response to chronic hypercapnia in goats

项目总结 慢性阻塞性肺疾病(COPD)影响着2400万美国成年人和全球超过10亿人。 慢性阻塞性肺疾病患者常伴有慢性高碳酸血症(CH，体内二氧化碳浓度升高)，严重的CH 随着疾病的发展而增加。慢性阻塞性肺病也以急性“发作”为特征，称为急性-慢性-慢性 加重，进一步增加体内的高碳酸血症水平。一些慢性阻塞性肺病患者表现出 可容忍的、适应性的对病情恶化的反应，而其他人则倾向于危及生命的严重 高碳酸血症和潜在致命的心肺功能障碍。慢性肝炎的严重程度可能是一个重要因素 在设定适应性反应与病理生理反应的敏感性阈值方面。事实上，我们之前的 研究结果表明，长期暴露在温和CH(6%吸入二氧化碳，InCO2)中的山羊表现出了适应能力 跨多个生理系统，并容忍吸入二氧化碳进一步急剧增加至7%和8%二氧化碳。相比之下， 在一项对一只山羊的初步研究中，将二氧化碳从轻度增加到中等水平(8%的二氧化碳)， 导致病理生理反应，无法补偿二氧化碳的急剧增加 9%和10%。慢性轻度慢性肝炎保护性/适应性反应的分子基础 慢性中度慢性脑出血的病理生理/适应不良反应尚不清楚。因此，总的目标是 这一建议是为了深入了解CH依赖的分子机制，它潜在地低于 保护性/适应性(AIM 1)和病理生理学/适应不良生理学(AIM 2)对二氧化碳增加的反应 挑战。对于目标1，我将成年山羊暴露在14天(D)的室内空气(组1)或温和的CH(组2)中。为 目的2将山羊暴露于轻度CH(6%CO2)7d，然后7d中度CH(8%CO2)(第3组)。这就做 在稳态期间测量跨多个生理系统的生理/病理生理响应 在气候条件下和在二氧化碳的严重挑战期间。在这些研究之后，山羊将被实施安乐死，我将提取组织 从关键的脑干心肺核团中提取并利用大宗组织mRNA测序(btRNA-Seq)来鉴定 轻度和中度慢性肝炎诱导差异表达基因。我将使用独创性路径分析 确定在轻度CH期间显著改变的典型途径和功能基因网络(6% CO2)，或7d轻度CH+7d中度CH(8%CO2)。结合广泛、公正的技术 (btRNA-Seq)和生理学研究将为调控的分子机制提供新的见解 先天性心脏病期间的心肺控制网络。此外，结果将产生对以下方面至关重要的信息 了解CH对门诊和ICU中观察到的生理功能障碍的影响。这个 这份提案中概述的培训计划将为我提供进行生理学所需的专业知识 拟议研究所需的实验、分子生物学技术和生物信息学分析。

PROJECT SUMMARY Chronic obstructive pulmonary disease (COPD) affects 24 million US adults and over 1 billion people worldwide. COPD patients often present with chronic hypercapnia (CH, elevated CO2 in the body), with severity of CH increasing as the disease progresses. COPD is also marked by acute “attacks”, known as acute-on-chronic exacerbations, further increasing the level of hypercapnia within the body. Some COPD patients demonstrate tolerable, adaptive responses to the exacerbations, whereas others are prone to life-threatening severe hypercapnia and potentially fatal cardiorespiratory dysfunction. The severity of CH may be an important factor in setting the threshold of susceptibility to adaptive versus pathophysiologic responses. Indeed, our previous findings have shown goats chronically exposed to mild CH (6% inspired CO2, InCO2) demonstrated adaptations across multiple physiologic systems and tolerated further acute increases in InCO2 to 7 and 8% CO2. In contrast, in a preliminary study on one goat, chronically increasing InCO2 from mild to moderate levels (8% InCO2), resulted in pathophysiologic responses and the inability to compensate for acute further increases in InCO2 to 9% and 10%. The molecular underpinnings governing the protective/adaptive responses to chronic mild CH or pathophysiologic/maladaptive responses to chronic moderate CH are unclear. Accordingly, the overall goal of this proposal is to gain insight into CH-dependent molecular mechanisms which potentially underly both the protective/adaptive (AIM 1) and pathophysiologic/maladaptive physiologic (AIM 2) responses to increased CO2 challenges. For AIM 1 I will expose adult goats to 14 days (d) of room air (Group 1) or mild CH (Group 2). For AIM 2, I will expose goats to 7d of mild CH (6% CO2) followed by 7d of moderate CH (8% CO2) (Group 3). I will measure physiological/pathophysiologic responses across multiple physiologic systems during steady-state conditions and during acute CO2 challenges. Goats will be euthanized after these studies and I will extract tissue from key brainstem cardiorespiratory nuclei and utilize bulk-tissue mRNA sequencing (btRNA-Seq) to identify differentially expressed genes induced by both mild CH and moderate CH. I will use Ingenuity Pathway Analysis to identify canonical pathways and functional gene networks that are significantly altered during mild CH (6% CO2) alone, or 7d mild CH followed by 7d of moderate CH (8% CO2). Combining broad, unbiased techniques (btRNA-Seq) and physiologic studies will provide novel insights into the molecular mechanisms regulating cardiorespiratory control networks during CH. Further, results will yield information that will be critical in understanding the effect CH has on the physiologic dysfunction observed in outpatient clinics and ICUs. The training plan outlined in this proposal will provide me with the expertise needed to conduct physiologic experiments, molecular biology techniques, and bioinformatic analyses required for the proposed studies.