5-HT Stimulation of Mitochondrial Biogenesis and Acute Kidney Injury

描述（由申请人提供）： 项目总结/摘要本项目的长期目标是确定急性器官衰竭的药物治疗。在缺血/再灌注（I/R）期间，由氧化应激诱导的细胞损伤和死亡发生，导致不同器官如心、脑、肝和肾的衰竭。I/R导致线粒体功能障碍，这是通过增强氧化剂产生和减少ATP合成而导致细胞损伤和死亡的主要机制。此外，氧化应激和线粒体功能障碍通常是药物、毒物和创伤诱导的细胞死亡的介质。不幸的是，没有真正有效的治疗方法可以促进细胞和器官修复/再生，以及损伤后器官功能的恢复。 细胞通过线粒体生物合成来取代陈旧和功能失调的线粒体。过氧化物酶体增殖物激活受体γ共激活因子-11（PGC-11）通常被认为是脂肪组织、心脏和肝脏中线粒体生物合成的主要调节因子，我们已经证明PGC-11介导了肾近端小管细胞（RPTC）中的线粒体生物合成。此外，我们最近表明，PGC-11的过度表达导致RPTC中的线粒体生物合成，并且氧化损伤后线粒体生物合成的增加加速了线粒体和细胞功能的恢复。这些令人兴奋的结果支持了损伤后线粒体生物合成可能有效刺激细胞和器官修复/再生的假设。 我们发现，5-羟色胺2型受体（5-HT 2）激动剂，1-（2，5-二甲氧基-4-碘苯基）-2-氨基丙烷（DOI），产生线粒体生物合成。RT-PCR分析从RPTC中分离的mRNA证实5-HT 2受体亚型5-HT 2A、5-HT 2B和5-HT 2C在人、兔、大鼠和小鼠中表达。这些结果表明，5-HT 2受体被发现在RPTC在多个物种，和5-HT 2受体的激活引起线粒体生物合成。最后，与单独的氧化损伤相比，氧化损伤后用DOI治疗RPTC加速了线粒体和细胞功能的恢复。此外，体内初步研究表明，DOI在小鼠肾脏中产生线粒体生物合成[并加速I/R后肾功能的恢复]。 这些研究支持了我们的总体假设，即特定的5-HT 2受体介导线粒体生物合成并加速急性肾损伤（阿基）后肾功能的恢复。以下特定目的将检验该假设：1）特定目的1：鉴定负责RPTC中线粒体生物发生的特定5-HT 2受体亚型，2）特定目的2：阐明RPTC中将5-HT 2受体活化与线粒体生物发生偶联的信号转导途径，以及3）特定目的3：在肾I/R小鼠模型中确定特异性5-HT 2受体激动剂对体内线粒体生物合成和肾功能恢复的功效。 这些研究将使用细胞和体内模型研究一种新的靶点，线粒体生物合成，以及一种新的线粒体生物合成途径，5-HT 2受体，用于治疗急性器官损伤，特别是阿基。我们将使用分子生物学，生物化学和药理学方法的组合来完成上述目标。最终，这些研究可能会导致新的治疗方法，以增加细胞和器官的生存和功能，在许多病理情况。

DESCRIPTION (provided by applicant): PROJECT SUMMARY/ABSTRACT The long-term goal of this project is to identify pharmacological treatments for acute organ failure. Cell injury and death induced by oxidative stress occur during ischemia/reperfusion (I/R), leading to failure of different organs such as heart, brain, liver and kidneys. I/R results in mitochondrial dysfunction, a major mechanism for cell injury and death via enhanced oxidant production and decreased ATP synthesis. Furthermore, oxidative stress and mitochondrial dysfunction is often the mediator of drug-, toxicant-, and trauma-induced cell death. Unfortunately, there are no truly effective therapies that can promote cell and organ repair/regeneration, and recovery of organ function following injury. Cells replace old and dysfunctional mitochondria through mitochondrial biogenesis. Peroxisome proliferator-activated receptor gamma coactivator-11 (PGC-11) is generally thought to be the master regulator of mitochondrial biogenesis in adipose tissue, heart, and liver, and we have shown that PGC-11 mediates mitochondrial biogenesis in renal proximal tubular cells (RPTC). In addition, we recently showed that over- expression of PGC-11 causes mitochondrial biogenesis in RPTC and that increasing mitochondrial biogenesis after oxidant injury accelerated recovery of mitochondrial and cellular functions. These exciting results support the hypothesis that post-injury mitochondrial biogenesis may be efficacious in stimulating cell and organ repair/regeneration. We discovered that the 5-hydroxytryptamine type 2 receptor (5-HT2) agonist, 1-(2,5-dimethoxy-4- iodophenyl)-2-aminopropane (DOI), produced mitochondrial biogenesis. RT-PCR analysis of mRNA isolated from RPTC confirmed the expression of 5-HT2 receptor subtypes 5-HT2A, 5-HT2B and 5-HT2C in humans, rabbits, rats and mice. These results demonstrate that 5-HT2 receptors are found in RPTC in multiple species, and that activation of the 5-HT2 receptors causes mitochondrial biogenesis. Finally, treatment of RPTC with DOI after oxidant injury accelerated the return of mitochondrial and cellular functions compared to oxidant injury alone. In addition, preliminary studies in vivo revealed that DOI produces mitochondrial biogenesis in the mouse kidney [and accelerates the recovery of renal function following I/R.] These studies support our overall hypothesis that a specific 5-HT2 receptor mediates mitochondrial biogenesis and accelerates the recovery of renal function following acute kidney injury (AKI). The following Specific Aims will test this hypothesis: 1) Specific Aim 1: Identify the specific 5-HT2 receptor subtype responsible for mitochondrial biogenesis in RPTC, 2) Specific Aim 2: Elucidate the signal transduction pathway that couples 5-HT2 receptor activation to mitochondrial biogenesis in RPTC, and 3) Specific Aim 3: Determine the efficacy of specific 5-HT2 receptor agonists on mitochondrial biogenesis in vivo and the recovery of renal function in a mouse model of renal I/R. These studies will examine a new target, mitochondrial biogenesis, and a novel pathway of mitochondrial biogenesis, 5-HT2 receptors, in the treatment of acute organ injury, specifically AKI, using cellular and in vivo models. We will use a combination of molecular biological, biochemical, and pharmacological approaches to complete the aims identified above. Ultimately, these studies may lead to new therapeutic approaches to increase cell and organ survival and function in numerous pathologic situations.