Influence of the Host Microbiome on the Mechanism of FVIII Immunogenicity: Project 3

项目 3. 摘要 ~30%重度血友病患者对因子(FVIII)的免疫应答 A(HA)是治疗这种疾病的最重要的并发症。抗FVIII抗体的形成 抗体(抑制物)极大地损害了这些患者的临床护理，以及他们随后 管理的可预测性较差，在实践中具有挑战性，而且往往成本高昂。这个 FVIII抑制剂的发病机制被认为是复杂和多因素的。大多数患者会发展成 这种并发症发生在FVIII替代疗法的前25次暴露期间，在最初的2-3次内 生命中的岁月。虽然有明显的遗传易感因素导致抑制剂的发育，例如 突变的F8基因，一系列获得性影响也会导致抑制风险。在这个项目中，我们将 调查到目前为止还没有在这方面进行研究的环境因素的作用--肠道 微生物组。有大量证据表明，肠道微生物群在 系统免疫系统的发展和调节，并且存在明显的联系 肠道微生物区系和某些形式的免疫病理学之间的关系。此外，微生物群 在生命的头两年经历显著的变化，也就是最初的FVIII治疗发生的时间 在患有严重HA的男孩中，以及FVIII抑制剂产生的最大风险时期。在此的项目3中 研究计划我们将解决与微生物群对FVIII抑制剂的影响相关的三个目标 队形。我们将首先评估变化对肠道微生物组相关代谢物的影响 环境对FVIII免疫原性的影响。特别是，我们将确定以下产品是否 色氨酸代谢与短链脂肪酸、醋酸酯、丁酸和丙酸的水平 影响静脉注射FVIII的先天和获得性免疫反应。在第二个 一系列实验，我们将利用我们最近开发的无菌HA小鼠进行研究 模特。在这些研究中，我们将首先评估FVIII抑制剂开发的可能性 在没有肠道微生物的情况下，然后将继续进行研究，在这些研究中，我们有选择地重新填充 通过各种策略建立肠道微生物区系，包括使用和不使用HA小鼠的粪便移植 FVIII抑制剂。最后，我们将进行研究，以评估肠道微生物群在调节 口服FVIII的免疫应答。这些实验将评估FVIII与 不同的抗原提呈细胞群，将决定FVIII的细胞因子和T细胞背景 肠道相关淋巴组织、肝和脾的免疫反应。总的来说，我们建议这一点 研究计划将提供关于肠道微生物组和 FVIII免疫原性。这一新信息很可能具有重大的生物学意义和潜在价值。 翻译含义。

Project 3 Abstract The development of an immune response to factor VIII (FVIII) in ~30% of persons with severe hemophilia A (HA) represents the most important complication of treating this condition. The formation of anti-FVIII antibodies (inhibitors) significantly compromises the clinical care of these patients, and their subsequent management is less predictable, practically challenging and often extraordinarily costly. The pathogenesis of FVIII inhibitors is recognized to be complex and multifactorial. Most patients that develop this complication do so during the first 25 exposures to FVIII replacement therapy, within the first 2-3 years of life. While there are clear genetic predisposing factors for inhibitor development, such as the mutant F8 genotype, a range of acquired influences also contribute to inhibitor risk. In this project, we will investigate the role of an environmental factor that, to date, has not been studied in this context – the gut microbiome. There is substantive evidence that the gut microbiome plays an important role in the development and regulation of the systemic immune system, and that there are clear associations between the gut microbiota and certain forms of immunopathology. In addition, the microbiome undergoes significant changes during the first two years of life, the time when initial FVIII treatment occurs in boys with severe HA, and the period of maximum risk for FVIII inhibitor generation. In Project 3 of this research program we will address three objectives related to microbiome influences on FVIII inhibitor formation. We will first evaluate the influence of changes to the gut microbiome-related metabolite environment on the immunogenicity of FVIII. In particular, we will determine whether the products of tryptophan metabolism and levels of the short chain fatty acids, acetate, butyrate and propionate influence innate and adaptive immune responses to intravenously administered FVIII. In the second series of experiments, we will conduct studies utilizing our recently developed germ-free HA mouse model. In these studies, we will begin with an assessment of the likelihood for FVIII inhibitor development in the absence of gut microbes, and will then progress to studies in which we selectively repopulate the gut microbiota through various strategies including fecal transplantation from HA mice with and without FVIII inhibitors. Lastly, we will conduct studies to evaluate the role of the gut microbiome in regulating the immune response to orally delivered FVIII. These experiments will assess the interaction of FVIII with various antigen presenting cell populations and will determine the cytokine and T cell context of the FVIII immune response in the gut associated lymphoid tissue, liver and spleen. Overall, we propose that this program of research will provide important new knowledge concerning the role of the gut microbiome and FVIII immunogenicity. This new information is very likely to have significant biological and potential translational implications.