REVERSAL OF HYPOVOLEMIC CIRCULATORY COLLAPSE BY IL-6

描述(由申请人提供)： 创伤是美国44岁以下儿童的主要死亡原因，几乎一半的死亡可归因于急性低血容量循环衰竭(AHCC)。AHCC的分子和细胞机制尚不清楚，需要有效的干预措施。为此，我们成功地建立了可复制的不可逆失血性休克(HS)动物模型，导致啮齿类动物AHCC，并建立了IL-6，当添加到液体复苏方案中时，能够完全逆转AHCC，并将死亡率降低5倍。在IL-6处理的动物的心脏中观察到STAT3活性增加，并伴随着心脏细胞凋亡的减少。使用本课题组开发的GQ-ODN在整个动物体内靶向STAT3，完全阻断了IL-6介导的心肌细胞凋亡的逆转和IL-6介导的AHCC的逆转。这一建议的总体假设是，在不可逆失血性休克(HS)期间，动物心肌细胞或内皮细胞内的必需基因产物减少到临界阈值以下，而IL-6通过STAT3作用于这些基因的转录，特别是那些与线粒体功能和细胞生存相关的基因的转录。这项建议的总体目标是：1)确定STAT3是否在AHCC的抵抗和IL-6的逆转中发挥作用；2)利用功能基因组学方法，以全面和公正的方式识别抵抗低血容量性循环衰竭的关键基因。我们列出了实现这些目标的两个重点明确的目标：目标1.确定STAT3在抗AHCC和被IL-6逆转中的作用，确定这些作用需要STAT3的哪种异构体，并确定在哪些细胞--心肌细胞或内皮--STAT3的作用是必不可少的。在这个目的中，我们将从药理学和遗传学上改变大鼠和小鼠心脏(如果需要的话，还有内皮细胞)中STAT3的活性，并研究在没有和有IL-6处理的情况下，STAT3活性改变对细胞凋亡和AHCC的影响。目的II.鉴定IL-6和STAT3在不可逆性HS小鼠和大鼠重要器官中维持或升高的mRNAs簇。我们将对小鼠和大鼠的心脏和肺组织的RNA进行Affymetrix寡核苷酸芯片分析，以确定其蛋白产物可能保护动物在不可逆性HS环境下免于低血容量性循环衰竭的候选基因清单。这些研究的长期目标是在整个动物中获得更好的分子和细胞理解，并确定必要器官中对抵抗低血容量性循环衰竭至关重要的基因。对这些基因的识别可能导致除IL-6外的治疗策略，诱导或维持它们的水平，从而改善患有严重HS的严重创伤患者的复苏结果。

DESCRIPTION (provided by applicant): Trauma is the leading cause of death in the US under the age of 44 with almost half of deaths attributable to acute hypovolemic circulatory collapse (AHCC). The molecular and cellular mechanisms of AHCC are not well understood and effective interventions are needed. Towards these ends, we have successfully developed reproducible models of irreversible hemorrhagic shock (HS) that leads to AHCC in rodents and established that IL-6, when added to the fluid resuscitation regimen, is capable of completely reversing AHCC and reducing mortality 5-fold. Increased Stat3 activity was observed in the hearts of IL-6-treatment animals and was accompanied by reduced cardiac apoptosis. Pharmacological targeting of Stat3 within the whole animal using a G-quartet oligodeoxynucleotide (GQ-ODN) developed by our group completely blocked both the IL-6-mediated reversal of cardiac apoptosis and the IL-6-mediated reversal of AHCC. The overall hypothesis of this proposal is that essential gene products are reduced below a critical threshold within the cardiomyocyte or endothelium of animals during irreversible hemorrhagic shock (HS) and that IL-6 acting through Stat3 maintains or increases the transcription of these genes especially those linked to mitochondrial function and cell survival. The overall goals of this proposal are: 1) to establish if Stat3 plays a role in resistance to AHCC and in its reversal by IL-6 and 2) to employ a functional genomic approach to identify genes critical for resistance to hypovolemic circulatory collapse in a comprehensive and unbiased manner. We have outlined 2 tightly focused SPECIFIC AIMS to accomplish these goals: AIM I. To establish the role of Stat3 in resistance to AHCC and in its reversal by IL-6, to establish which isoform of Stat3 is required for these effects and to identify in which cells--cardiomyocytes or endothelium--is the action of Stat3 essential. In this AIM, we will pharmacologically and genetically alter the activity of Stat3 within the heart (and endothelium, if necessary) of rats and mice and examine the effects of altered Stat3 activity on cell apoptosis and AHCC without and with IL-6 treatment. AIM II. To identify the cluster of mRNAs whose levels are maintained or increased in the vital organs of mice and rats subjected to irreversible HS by IL-6 and Stat3. We will perform Affymetrix oligonucleotide microarray analysis of RNA from the heart and lung of mice and rats to identify the list of candidate genes whose protein products may protect animals from hypovolemic circulatory collapse in the setting of irreversible HS. The long-term goals of these studies are to gain an improved molecular and cellular understanding of AHCC in the whole animal and to identify genes within essential organs that are critical for resistance to hypovolemic circulatory collapse. Identification of these genes may lead to therapeutic strategies in addition to IL-6 that induce or maintain their levels resulting in improved resuscitation outcomes in patients with serious traumatic injuries suffering from severe HS.