Preventing lethal hemorrhagic fever caused by hantaviruses by preserving endothel

描述（由申请人提供）： 病毒性出血热（VHF）激活先天免疫系统，引发细胞因子和其他渗透性因子的大量释放，使内皮屏障不稳定。血管完整性的丧失导致非心源性水肿、休克、多器官衰竭和死亡。虽然已经在多种形式的出血热中研究了VHF诱导的内皮破裂与死亡率之间的关系，但是已经在汉他病毒中充分建立了这种关系;特别是在新世界汉他病毒肺综合征（HPS）中，其特征是发热和血管渗漏，导致非心源性肺水肿，严重病例随后发生休克和死亡2。在过去的一年里，关于汉坦病毒感染内皮细胞并导致其破裂的机制已经有了重大发现。在2010年，Mackow及其同事报道，汉坦病毒直接增强响应VEGF的VE-钙粘蛋白的内化，从而解离调节血管通透性的内皮细胞粘附连接3。Navigen Pharmaceuticals正在开发一种治疗性蛋白质Slit 2N，我们已经证明它可以减少细胞因子诱导的VE-钙粘蛋白内化引起的血管渗漏4。最近的证据表明汉坦病毒引起VE-钙粘蛋白的内化，结合Navigen发现Slit 2N可以阻止VE-钙粘蛋白内化，使我们相信我们必须优先检测汉坦病毒中的Slit 2N。这一结论进一步得到以下事实的支持：我们已经表明，Slit 2N可以降低细胞因子风暴被认为会诱导大量内皮细胞破坏和血管渗漏的疾病模型中的死亡率4。Navigen认为，Slit 2N可能在治疗病毒性出血热方面具有广谱疗效，因为有证据表明VE-钙粘蛋白内化在与其他出血热（包括登革热5和炭疽诱导剂6）相关的血管渗漏中发挥作用。此外，Slit 2N已被证明可以预防与大量细胞因子风暴相关的许多其他疾病（包括败血症）中血管渗漏导致的死亡。我们建议使用汉坦病毒肺综合征来说明VHF形式的功效，其与Slit 2N的作用机制有最清楚的联系，防止由汉坦病毒诱导的VE-钙粘蛋白内化引起的血管内皮细胞连接破裂。确定Slit 2N治疗HPS的最有效剂量和剂量方案可能导致第一个批准的治疗汉坦病毒肺综合征的疗法，并将为将测试扩展到其他形式的VHF奠定基础，其中血管渗漏被认为对死亡率有显着贡献（例如埃博拉病毒，拉沙热病毒，登革热病毒等）。在本项目中，我们将确定Slit 2N治疗叙利亚仓鼠HPS的最有效剂量。一旦确定了最佳剂量，我们将试验剂量定时，以确定Slit 2N在疾病过程中的有效时间。我们还将测试Slit 2N与抗病毒利巴韦林的联合使用，以确定是否如我们所假设的那样，Slit 2N与抗病毒药物联合使用会比单独使用任何一种治疗产生更好的结果。除确定仓鼠中适当剂量范围的基础药代动力学研究外，IND使能药代动力学和毒理学工作将在一个单独的项目下得到支持。具体目的1：研究仓鼠中的Slit 2N药代动力学（PK）和7天耐受性。具体目的2：研究Slit 2N抗ANDV的剂量反应效力。具体目的3：研究Slit 2N延迟治疗对ANDV的疗效。具体目的4：研究Slit 2N与利巴韦林联合使用的疗效。

DESCRIPTION (provided by applicant): Viral hemorrhagic fever (VHF) activates the innate immune system triggering an exuberant release of cytokines and other permeability factors that destabilize the endothelial barrier. The loss of vascular integrity results in non-cardiogenic edema, shock, multi-organ failure and death. While the relationship between VHF- induced endothelial breakdown and mortality has been studied in multiple forms of hemorrhagic fever, it has been well established in hantavirus; specifically in New-world hantavirus pulmonary syndrome (HPS) which is characterized by fever and vascular leakage resulting in noncardiogenic pulmonary edema followed in severe cases by shock and death2. In the past year, significant discoveries have been made regarding the mechanisms by which hantaviruses infect endothelial cells and lead to their breakdown. In 2010, Mackow and associates reported that hantaviruses directly enhance the internalization of VE-cadherin in response to VEGF and thereby dissociate endothelial cell adherence junctions which regulate vascular permeability3. Navigen Pharmaceuticals is developing a therapeutic protein, Slit2N, which we have shown to reduce vascular leak resulting from cytokine- induced VE-cadherin internalization4. The recent evidence that hantaviruses cause internalization of VE- cadherin combined with Navigen's discovery that Slit2N can prevent VE-cadherin internalization leads us to believe that we must make testing Slit2N in hantavirus a priority. This conclusion is supported further by the fact that we have shown that Slit2N can reduce mortality in models of conditions in which cytokine storm is believed to induce massive endothelial breakdown and vascular leak4. Navigen believes that Slit2N may have broad-spectrum efficacy in the treatment of viral hemorrhagic fevers as there is evidence that VE-cadherin internalization plays a role in the vascular leak associated with other hemorrhagic fevers including Dengue5 and hemorrhage-inducing agent anthrax6. Additionally, Slit2N has been shown to prevent mortality from vascular leak in a number of other conditions associated with massive cytokine storm, including sepsis4. We propose to use Hantavirus pulmonary syndrome to illustrate efficacy in a form of VHF with the clearest link to Slit2N's mechanism of action, preventing the vascular endothelial cell junction breakdown caused by hantavirus-induced VE-cadherin internalization. Identification of the most efficacious dose and dose schedule for Slit2N in treating HPS could lead to the first approved therapy to treat Hantavirus Pulmonary Syndrome and would set the stage for expanding testing to other forms of VHF in which vascular leak is believed to contribute significantly to mortality (e.g. Ebola virus, Lassa fever virus, Dengue virus, etc.). In this project, we would identify the most efficacious dose of Slit2N in treating HPS in Syrian hamsters. Once the optimal dose is identified, we will experiment with dose timing to determine how late in the course of the disease Slit2N can be effective. We will also test Slit2N in conjunction with the anti-viral ribavirin in an effort to determine whether, as we hypothesize, Slit2N in combination with an anti-viral will result in better outcomes than with either therapy alone. With the exception of basic pharmacokinetic studies to identify appropriate dose ranges in hamsters, IND-enabling pharmacokinetic and toxicology work will be supported under a separate project. Specific Aim 1: Investigate Slit2N pharmacokinetics (PK) and 7-day tolerability in hamsters. Specific Aim 2: Investigate dose-response efficacy of Slit2N against ANDV. Specific Aim 3: Investigate efficacy of delayed therapy with Slit2N against ANDV. Specific Aim 4: Investigate efficacy of Slit2N in combination with ribavirin.