PPARgamma and PPARgamma agonists in septic shock

描述（由申请人提供）：在美国，严重脓毒症每年发生在超过75万名患者中，是重症监护病房发病率和死亡率的主要原因。细菌产物激活促炎细胞导致炎症介质的释放，诱导败血症的全身炎症反应。这些介质的产生在转录水平上由增强子核因子κ b （nf - κ b）和激活蛋白-1 （AP-1）通过与特定激酶的相互作用进行调控。在初步的体外和体内研究中，我们已经获得证据表明，脓毒症的全身炎症反应可能受到核报告细胞过氧化物酶体增殖物激活受体γ (PPARgamma)的反调节。特异性PPARgamma配体15deoxy-delta12,14- pgj2 （15d-PGJ2）或噻唑烷二酮曲格列酮预处理巨噬细胞，可抑制细菌脂多糖（LPS）和热杀伤金黄色葡萄球菌（HK S. aureus）诱导的促炎介质。与这一发现一致，我们发现PPARgamma配体提高了盲肠结扎穿刺所致脓毒性休克大鼠的存活率，减少了血流动力学改变、细胞因子的产生和肺、结肠和肝脏的中性粒细胞浸润。我们的中心假设是核受体PPARgamma是一个关键的抗炎途径，PPARgamma的激活对感染性休克是有益的。三个相互关联的具体目标将检验这一假设。(1)我们将在体内评价PPARgamma配体治疗多微生物脓毒症时心血管紊乱和器官衰竭的疗效。15d-PGJ2、噻唑烷二酮类和非噻唑烷二酮类PPARgamma配体对盲肠结扎穿刺大鼠脓毒性后遗症的影响将在体内进行研究。(2)研究PPARgamma配体在多微生物脓毒症中的分子机制。PPARgamma配体对NF-kappaB和AP-1及其调控激酶的核活化的影响将被研究。(3)我们将确定环戊烯前列腺素和PPARgamma在体外LPS和HK金黄色葡萄球菌攻击巨噬细胞/单核细胞中调节细胞信号传导和炎症介质产生的作用。该方法将使用PPARgamma的药理学拮抗剂，并对来自Cre-lox小鼠的PPARgamma显性/阴性构建体和PPARgamma缺陷巨噬细胞进行遗传操作。体内和体外方法的结合将为PPARgamma的激活对败血症有益的假设提供强有力的检验。

DESCRIPTION (provided by applicant): Severe sepsis occurs in over 750,000 patients each year in the United States and is the leading cause of morbidity and mortality in critical care units. Activation of pro-inflammatory cells by bacterial products leads to a release of inflammatory mediators that induces the systemic inflammatory response of sepsis. The production of these mediators is regulated at the transcriptional level by enhancer elements nuclear factor kappaB(NF-kappaB) and activator protein-1 (AP-1) through interactions with specific kinases. In preliminary in vitro and in vivo studies we have obtained evidence that the systemic inflammatory response of sepsis may be counter-regulated by the nuclear reporter peroxisome proliferator activated receptor-gamma (PPARgamma). Pretreatment of macrophages with the specific PPARgamma ligands 15deoxy-delta12,14-PGJ2 (15d-PGJ2) or the thiazolidinedione troglitazone inhibits pro-inflammatory mediators induced by bacterial lipopolysaccharide (LPS) and heat killed Staphylococcus aureus (HK S. aureus). Consistent with this finding, we have found that PPARgamma ligands improve survival, reduce hemodynamic alterations, cytokine production and neutrophil infiltration in lung, colon and liver in rats subjected to septic shock induced by cecal ligation and puncture. Our central hypothesis is that the nuclear receptor PPARgamma is a critical anti-inflammatory pathway and that PPARgamma activation is beneficial in septic shock. Three interrelated specific aims will test this hypothesis. (1) We will evaluate the therapeutic efficacy of PPARgamma ligands on cardiovascular derangement and organ failure during polymicrobial sepsis in vivo. The effects of 15d-PGJ2, thiazolidinediones and nonthiazolidinedione PPARgamma ligands on septic sequelae will be examined in vivo in rats subjected to cecal ligation and puncture. (2) We will identify the molecular mechanisms of the actions of PPARgamma ligands in polymicrobial sepsis in vivo. The effect of PPARgamma ligands on nuclear activation of NF-kappaB and AP-1 and their regulatory kinases will be examined. (3) We will determine the role of cyclopentencne prostaglandins and PPARgamma in regulating cell signaling and inflammatory mediator production in macrophages/monocytes challenged in vitro with LPS and HK S. aureus. This approach will employ pharmacologic antagonists of PPARgamma and genetic manipulations with PPARgamma dominant/negative constructs and PPARgamma deficient macrophages from Cre-lox mice. The combination of in vivo and in vitro approaches will provide a strong test of the hypothesis that activation of PPARgamma is beneficial in sepsis.