The microbiome determines organ damage development in sickle cell disease

项目总结： 镰状细胞病(SCD)是美国最常见的遗传性血液疾病，影响7万人- 10万美国人。SCD是由β-珠蛋白基因突变引起的，该突变导致 红细胞膜，促进红血球与其他细胞的黏附，导致血管闭塞 剧集(VoE)。慢性SCD伴有进行性、全身性多器官功能障碍和 每年的入院费用为4.75亿美元。 我们最近的工作表明，抗生素耗尽SCD小鼠的微生物区系会减少器官 损坏和铁超载。我们的初步数据显示，在没有细菌的情况下，器官损害得到显著改善 SCD小鼠与无特定病原体的SCD小鼠的比较，证实了器官中微生物区系的重要性 破坏发展。16S rDNA测序分析发现一种候选细菌--肠球菌 鸡毒杆菌--这可能会促进SCD小鼠的器官损伤。此外，我们还证明了 与饲喂铁限制饮食的SCD小鼠相比，饲喂限铁饮食的SCD小鼠表现出明显的器官损伤逆转 控制饮食。 在目前的申请中，我们提出了一个为期5年的实验计划，以促进我们对 微生物区系对SCD疾病进展的影响，并测试微生物区系的潜在操纵性 新的SCD治疗。在具体目标1中，我们将确认鸡肠杆菌是否具有致病作用。 细菌影响SCD小鼠器官损伤的进展。此外，我们将调查是否 鸡肠杆菌特异性疫苗减少了SCD小鼠的器官损伤负担。我们将探索微生物区系-- 引起SCD小鼠器官损伤的相关机制。具体地说，我们将研究微生物区系如何 通过分析相关的肠道通透性参数，如紧密连接和粘液层，绕过肠道屏障 正直。我们推测，一旦鸡肠杆菌从门静脉转移到肝脏，它就会上调T 辅助17(Th17)细胞，招募其他炎症细胞来诱导SCD小鼠的器官损伤。在……里面 具体目标2，我们将探索膳食铁在肠道微生物区系存活中的作用，以及膳食铁是否 参与破坏SCD小鼠肠道屏障的完整性。这些拟议的研究侧重于 在SCD中的微生物区系操作，将使我们能够识别导致SCD的关键微生物物种 病理生理学，并可能提供新的，成本效益高的方法来管理SCD的终身 并发症。

Project Summary: Sickle cell disease (SCD) is the most common inherited blood disorder in the United States, affecting 70,000- 100,000 Americans. SCD is caused by a mutation in the β-globin gene that leads to significant deformation of the red blood cell (RBC) membrane and promotes RBC adhesion to other cells, inducing vaso-occlusive episodes (VOE). Chronic SCD is accompanied by progressive, systemic multi-organ dysfunction and costs over $475 million annually in hospital admissions. Our recent work demonstrates that the depletion of microbiota in SCD mice by antibiotics reduces organ damage and iron overload. Our preliminary data show that organ damage is significantly improved in germ-free SCD mice compared to specific-pathogen-free SCD mice, confirming the importance of microbiota in organ damage development. Analysis by 16S rDNA sequencing uncovered a candidate bacterium—Enterococcus gallinarum (E. gallinarum)—that may promote organ damage in SCD mice. Additionally, we demonstrate that SCD mice fed an iron-restricted diet exhibit significant reversal of organ damage compared with SCD mice fed a control diet. In the current application, we propose a 5-year experimental plan to advance our understanding of the microbiota-mediated effects on SCD disease progression and to test the manipulation of microbiota as a potential novel SCD treatment. In Specific Aim 1, we will confirm whether E. gallinarum functions as a pathogenic bacterium to influence the progression of organ damage in SCD mice. Additionally, we will investigate whether an E. gallinarum–specific vaccine reduces organ damage burden in SCD mice. We will explore the microbiota- related mechanisms that induce organ damage in SCD mice. Specifically, we will study how microbiota can bypass the gut barrier by analyzing relevant gut permeability parameters such as tight junction and mucus layer integrity. We hypothesize that once E. gallinarum translocates from the portal vein to the liver, it upregulates T helper 17 (Th17) cells that recruit other inflammatory cells to induce the organ damage seen in SCD mice. In Specific Aim 2, we will explore the role of dietary iron in gut microbiota survival and whether dietary iron is involved in disrupting gut barrier integrity in SCD mice. These proposed studies, focused on strategies of microbiota manipulation in SCD, will allow us to identify the key microbial species that contribute to SCD pathophysiology and potentially provide novel, cost-effective approaches for managing SCD’s life-long complications.