Elucidation of Beta-2 Adrenergic Receptor Pathways Leading to Mitochondrial Biogenesis

阐明导致线粒体生物发生的 Beta-2 肾上腺素受体途径

• 批准号: 8836017
• 负责人: Robert Bruce Cameron
• 金额: $ 4.4万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-30 至 2019-07-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8836017
• 关键词: Acute; Acute Renal Failure with Renal Papillary Necrosis; Address; Adrenergic Agonists; Adrenergic Receptor; Adverse effects; Affect; Affinity; Agonist; Biogenesis; Cell Respiration; Cells; Cyclic GMP; Data; Development; Drug Exposure; Drug usage; Event; Exhibits; Exposure to; Failure; Gases; Generations; Goals; Immunoblot Analysis; In Vitro; Injury; Intervention; Laboratories; Lead; Mitochondria; Mitochondrial Proteins; Molecular Conformation; Morbidity - disease rate; Mus; Onset of illness; Organ; Organ failure; Oxidative Stress; PPAR gamma; Pathway interactions; Patients; Phosphorylation Site; Process; Production; Proximal Kidney Tubules; Receptor Signaling; Recovery; Renal function; Reperfusion Injury; Role; Signal Pathway; Signal Transduction; Site-Directed Mutagenesis; Small Interfering RNA; Tissues; Toxicant exposure; beta-2 Adrenergic Receptors; cGMP production; design; effective therapy; in vivo; in vivo Model; inhibitor/antagonist; injured; mitochondrial dysfunction; mortality; novel; novel therapeutics; public health relevance; receptor; renal ischemia; repaired; restoration

DESCRIPTION (provided by applicant): Acute kidney injury (AKI) is a severe, rapid-onset disease characterized by a rapid loss in renal function leading to substantial morbidity and mortality. Frequent causes of AKI include ischemia/reperfusion (I/R) injury and acute drug or toxicant exposure. Despite attempts to develop new therapeutic strategies to treat AKI, few have been successful, and mortality has remained unchanged for several decades. Therefore, novel targets must be examined for the development of useful therapies for AKI. It has been shown that renal proximal tubule cells exhibit severe mitochondrial dysfunction and depletion of mitochondrial proteins following toxicant exposure or I/R injury. Mitochondrial dysfunction leads to oxidative stress and persistent energy depletion, which exacerbates injury and impairs energy-dependent repair, leading to end organ damage and failure in a variety of tissues. Our laboratory has demonstrated that injured renal proximal tubules can recover if they are induced to generate new mitochondria through mitochondrial biogenesis (MB). In addition, our laboratory has identified several compounds capable of inducing MB in vitro and in in vivo models of AKI. Among these compounds are several b2 adrenergic receptor (b2AR) agonists; however, not all b2AR agonists were found to induce MB. The capacity of these compounds to induce MB biogenesis did not correlate with affinity, but did correlate with the capacity of these compounds to increase levels of cGMP. In turn, cGMP has been shown to induce MB by increasing the activity of peroxisome proliferator-activated receptor gamma coactivator-1a (PGC1a), the master regulator of MB. We hypothesize that biogenic b2AR agonists stimulate MB and promote recovery of renal function by inducing a specific receptor conformation that leads to the production of cGMP. This hypothesis will be addressed through the following Specific Aims. Aim 1 will determine the effects of mitochondrial biogenic agonists-induced effects on the b2AR that lead to a biogenic conformation. Site-directed mutagenesis and immunoblot analysis will identify b2AR phosphorylation sites required for the induction of MB. Aim 2 will elucidate the role of Gas- and Gai-dependent signaling pathways in the generation of cGMP and the induction of MB. Pharmacologic inhibitors and siRNA will identify the relevant signaling pathways for the induction of MB. Non-MB b2AR agonists will be used as controls. Aim 3 will determine the b2AR signaling pathways found in Aims 1 and 2 in the recovery of renal function following I/R injury using b2AR KO mice and pharmacological inhibitors. These results will further support the approach of using drugs that induce MB to accelerate recovery of renal function after AKI.

描述（由申请人提供）：急性肾损伤（AKI）是一种严重的、快速发病的疾病，其特征是肾功能迅速丧失，导致大量的发病率和死亡率。 AKI 的常见原因包括缺血/再灌注 (I/R) 损伤以及急性药物或毒物暴露。尽管尝试开发新的治疗策略来治疗 AKI，但很少成功，死亡率几十年来一直保持不变。因此，必须研究新的靶点以开发 AKI 的有效疗法。研究表明，肾近曲小管细胞在接触毒物或缺血再灌注损伤后表现出严重的线粒体功能障碍和线粒体蛋白消耗。线粒体功能障碍导致氧化应激和持续能量消耗，从而加剧损伤并损害能量依赖性修复，导致多种组织的终末器官损伤和衰竭。我们的实验室已经证明，如果通过线粒体生物发生 (MB) 诱导受损的肾近曲小管产生新的线粒体，则受损的肾近曲小管可以恢复。此外，我们的实验室还鉴定了几种能够在体外和体内 AKI 模型中诱导 MB 的化合物。这些化合物包括几种 b2 肾上腺素受体 (b2AR) 激动剂；然而，并非所有 b2AR 激动剂都能诱导 MB。这些化合物诱导MB生物发生的能力与亲和力无关，但与这些化合物增加cGMP水平的能力相关。反过来，cGMP 已被证明可以通过增加过氧化物酶体增殖物激活受体 γ 辅激活剂-1a (PGC1a)（MB 的主要调节剂）的活性来诱导 MB。我们假设生物源 b2AR 激动剂通过诱导特定受体构象（导致 cGMP 的产生）来刺激 MB 并促进肾功能的恢复。这一假设将通过以下具体目标得到解决。目标 1 将确定线粒体生物激动剂诱导的对 b2AR 的影响，从而导致生物构象。定点诱变和免疫印迹分析将鉴定诱导 MB 所需的 b2AR 磷酸化位点。目标 2 将阐明 Gas 和 Gai 依赖性信号通路在 cGMP 生成和 MB 诱导中的作用。药理学抑制剂和 siRNA 将确定诱导 MB 的相关信号传导途径。非 MB b2AR 激动剂将用作对照。目标 3 将使用 b2AR KO 小鼠和药物抑制剂确定目标 1 和 2 中发现的 b2AR 信号通路在 I/R 损伤后肾功能恢复中的作用。这些结果将进一步支持使用诱导MB药物加速AKI后肾功能恢复的方法。