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

项目摘要 慢性阻塞性肺病（COPD）影响着2400万美国成年人和全球超过10亿人。 COPD患者通常表现为慢性高碳酸血症（CH，体内CO2升高），严重程度为CH 随着疾病的进展而增加。慢性阻塞性肺病也以急性“发作”为特征，称为慢性急性发作 病情加重，进一步增加体内高碳酸血症的水平。一些COPD患者表现出 可耐受的，适应性反应的加重，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。CH的严重程度可能是一个重要因素 在设定适应性与病理生理反应的敏感性阈值方面。的确，我们的前 研究结果表明，山羊长期暴露于轻度CH（6%的吸入CO2，InCO 2）中表现出适应性 在多个生理系统中，并耐受InCO 2进一步急性增加至7和8%CO2。与此相反， 在对一只山羊的初步研究中，将InCO 2从轻度水平慢性增加到中度水平（8%InCO2）， 导致病理生理反应和无法补偿InCO 2的急性进一步增加， 9%和10%。控制对慢性轻度CH或CH的保护性/适应性反应的分子基础 慢性中度CH的病理生理/适应不良反应尚不清楚。因此， 这一建议是为了深入了解CH依赖的分子机制，这些机制可能是 保护性/适应性（AIM 1）和病理生理/适应不良生理（AIM 2）对CO2增加的反应 挑战对于AIM 1，我将成年山羊暴露于室内空气（第1组）或轻度CH（第2组）14天（d）。为 目的2：将山羊暴露于轻度CH（6%CO_2）7 d，然后暴露于中度CH（8%CO_2）7 d（组3）。我会 测量稳态期间多个生理系统的生理/病理生理反应 在急性CO2挑战期间。在这些研究之后，山羊将被安乐死， 从关键的脑干心肺神经核，并利用大量组织mRNA测序（btRNA-Seq），以确定 差异表达的基因由轻度CH和中度CH诱导。我将使用不相容性途径分析 确定在轻度CH（6%）期间显著改变的典型途径和功能基因网络， CO2）单独给药，或7天轻度CH，随后7天中度CH（8%CO2）。结合广泛的，无偏见的技术 （btRNA-Seq）和生理学研究将为调节细胞凋亡的分子机制提供新的见解。 此外，结果将产生信息，这将是至关重要的， 了解CH对门诊和ICU中观察到的生理功能障碍的影响。的 本建议书中概述的培训计划将为我提供进行生理检查所需的专业知识。 实验，分子生物学技术，和生物信息学分析所需的拟议研究。

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.