Understanding genetic basis for resistance to TNF-induced lethal shock using new

描述（由申请人提供）：中毒性休克导致的死亡，是由感染因子引发巨噬细胞过度合成肿瘤坏死因子（TNF）和其他炎症分子引起的，仍然是一个主要的健康问题。本研究首次描述了野生源性MSM小鼠对脂多糖（LPS）的抵抗和tnf诱导的体内死亡，代表了一种新的中毒性休克抵抗遗传模型。这些小鼠对中毒性休克的显著抵抗进一步强调了它们对TNF和d -半乳糖胺共同给药引起的急性肝损伤缺乏敏感性，d -半乳糖胺是一种成熟的内毒素肝损伤体内模型。为了支持体内耐药数据，我们发现原发MSM巨噬细胞表现出另一种表型，它们在体外对TNF-或tlr激动剂诱导的受调节的坏死（“坏死性坏死”）有耐药性，但对凋亡细胞死亡没有耐药性。基于这些结果，我们假设这两个性状存在机制联系，并建议通过遗传连锁分析来研究坏死性下垂和中毒性休克性状之间的联系，旨在鉴定赋予这两个性状的位点。在进一步扩展体外实验结果时，我们发现tnf介导的体内肝损伤可以通过一种关键坏死性坏死调节因子RIP1激酶的特异性抑制剂来预防。除了细胞死亡表型外，我们还证明MSM巨噬细胞的TNF合成减少，并且也可能受到体内RIP1信号的影响。根据我们的初步数据，我们认为RIP1激酶是急性中毒性休克的介质，可能是治疗干预的重要新靶点。我们建议进一步表征体外MSM肝细胞和巨噬细胞对TLR激动剂和TNF反应的变化范围，以便更好地确定MSM抗中毒性休克的细胞基础。总的来说，这些研究可能为体内中毒性休克和坏死性RIP1激酶信号传导的机制提供重要的新见解，RIP1激酶信号传导也涉及其他急性病理，如中风、心肌梗死和脑外伤。

DESCRIPTION (provided by applicant): Mortality from toxic shock, caused by infective agents that trigger excessive synthesis of tumor necrosis factor (TNF) and other inflammatory molecules by macrophages, remains a major health problem. Here we describe for the first time resistance to lipopolysaccharide (LPS) and TNF-induced death in vivo of wild-derived mice of MSM strain, representing a new genetic model of resistance to toxic shock. The remarkable resistance of these mice to toxic shock is further emphasized by their lack of sensitivity to acute liver injury caused by the co-administration of TNF and D-galactosamine, a well-established in vivo model of endotoxic liver damage. In support of the in vivo resistance data, we show that primary MSM macrophages exhibit another phenotype in that they are resistant to TNF- or TLR-agonists-induced regulated necrosis ("necroptosis") but not apoptosis cell death in vitro. Based on these results, we hypothesize that the two traits are mechanistically linked and propose to examine the connection between necroptosis and toxic shock traits by means of genetic linkage analysis aimed at identification of the loci, which confer both traits. In further extension of the in vitro results, we discovered that TNF-mediated in vivo liver injury can be prevented by a specific inhibitor of a key necroptosis regulator, RIP1 kinase. In addition to cell death phenotype, we demonstrate that TNF synthesis by MSM macrophages is reduced and may also be influenced by RIP1 signaling in vivo. Based on our preliminary data, we suggest that RIP1 kinase is a mediator of acute toxic shock and may represent an important new target for therapeutic intervention. We propose to further characterize the scope of changes in in vitro MSM hepatocyte and macrophage responses to TLR agonists and TNF in order to better determine the cellular basis for MSM resistance to toxic shock. Overall, these studies may provide important new insights into mechanisms of both toxic shock in vivo and necroptotic RIP1 kinase signaling, which has also been implicated in other acute pathologies, such as stroke, myocardial infarction and brain trauma. PUBLIC HEALTH RELEVANCE: Mortality from toxic shock, caused by infective agents that trigger excessive synthesis of tumor necrosis factor (TNF) and other inflammatory molecules by macrophages remains a major health problem. In this proposal, using genetic analysis of resistance to toxic shock in the wild-derived mice, we will reveal novel mechanisms of control of inflammation and its magnitude.