Targeting Siglec-8/-F to treat eosinophil and mast cell related disorders

描述（由申请人提供）：在过敏反应、哮喘和其他形式的急慢性过敏性疾病中，嗜酸性粒细胞和肥大细胞通过释放预先形成的和新生成的介质、颗粒蛋白和细胞因子，被认为是关键的效应细胞。对于过敏性疾病，抑制肥大细胞脱颗粒、减少嗜酸性粒细胞数量或中和其释放的介质的药物是有用的治疗方法，但所有药物都不完全有效。嗜酸性粒细胞和肥大细胞与包括嗜酸性粒细胞性食管炎在内的其他慢性疾病有关。全身性肥大细胞增多症是一种恶性疾病，其预后因受累程度的不同而不同，但由于缺乏有效的治疗，侵袭性全身性肥大细胞增多症和肥大细胞白血病往往是致命的。对于嗜酸性粒细胞相关的恶性肿瘤，经修订的2008年世卫组织分类承认分子定义的和未定义的髓系疾病，对不明原因的嗜酸性粒细胞增多症和“未另行说明的慢性嗜酸性粒细胞白血病”的治疗需求仍未得到满足。Siglecs（唾液酸结合免疫球蛋白样凝集素）是主要存在于白细胞上的细胞表面蛋白。siglece -8是我们大约在十年前发现的，它在嗜酸性粒细胞和肥大细胞上选择性表达。它在小鼠中的功能最相似的是siglece - f，它也被嗜酸性粒细胞选择性地表达，但不幸的是，它不在肥大细胞上表达。siglece -8和siglece - f都优先且唯一地识别6'-磺基-硅基Lewis X（6'-磺基- slex）及其非聚焦形式。Siglec- 8/- f与抗体（Abs）和/或人工配体结合可导致嗜酸性粒细胞死亡。在慢性过敏性哮喘和嗜酸性粒细胞增多的小鼠模型中给予siglece - f抗体可使嗜酸性粒细胞炎症反应正常化并消除肺重构。该申请是R01 AI72265的竞争性更新，题为“靶向siglece -8/ siglece - f以减少体外和体内的过敏反应”，资助时间为7/01/07-06/30/12，ARRA补充时间为7/01/10-06/30/11。总体目标是探索siglece -8/-F的配体，它们的功能，以及它们调节嗜酸性粒细胞和过敏反应的机制。自2007年以来，我们发表了14篇与该奖项相关的论文，并获得了5项与siglece -8相关的专利。本应用程序的目标是在高度翻译，体外临床前和小鼠研究（包括siglece -8突变学）中使用siglece -8的单克隆抗体（mab）和聚糖配体，以确定其作为治疗靶点的效用。创新包括脂质体靶向，通过选择性靶向siglece -8/-F携带细胞来降低有效载荷药物的全身毒性，从而减少药物的总剂量。提出的方法包括使用纳米颗粒成像食管嗜酸性粒细胞炎症（Aim 1），通过靶向siglece -8/-F及其配体选择性地向嗜酸性粒细胞或肥大细胞递送抑制药物，以治疗涉及这些细胞的过敏性和炎症性疾病（Aim 2），以及使用靶向siglece -8/-F的脂质体携带化疗药物或我们的siglece -8单抗治疗涉及嗜酸性粒细胞和肥大细胞的恶性疾病（Aim 3）。

DESCRIPTION (provided by applicant): In anaphylaxis, asthma and other forms of acute and chronic allergic diseases, eosinophils and mast cells, through release of preformed and newly generated mediators, granule proteins, and cytokines, are felt to be key effector cells. For allergic diseases, drugs that inhibit mast cell degranulation, reduce eosinophil numbers, or counteract their released mediators are useful therapies, but all remain incompletely effective. Eosinophils and mast cells are implicated in other chronic diseases including eosinophilic esophagitis. Systemic Mastocytosis, a malignant disease, presents with varying prognoses depending on the extent of involvement, but Aggressive Systemic Mastocytosis and Mast Cell Leukemia are always fatal due to the lack of effective treatments. For eosinophil-related malignancies, the revised 2008 WHO classification recognizes both molecularly defined and undefined myeloid disorders, and there remains an unmet need for treatment of unexplained eosinophilia and "chronic eosinophilic leukemia, not otherwise specified". Siglecs (sialic acid-binding, immunoglobulin-like lectins) are cell surface proteins found predominantly on leukocytes. Siglec-8 was discovered by us about a decade ago and is selectively expressed on eosinophils and mast cells. Its closest functional paralog in the mouse is Siglec-F, which is also selectively expressed by eosinophils but unfortunately not on mast cells. Both Siglec-8 and Siglec-F preferentially and uniquely recognize the glycan 6'-sulfo-sialyl Lewis X (6'-sulfo-sLeX) and its non-fucosylated form. Engagement of Siglec- 8/-F with antibodies (Abs) and/or artificial ligands causes eosinophil death. Administration of Siglec-F Abs in mouse models of chronic allergic asthma and eosinophilia normalizes eosinophilic inflammatory responses and abrogates lung remodeling. This application is a competitive renewal of R01 AI72265 entitled "Targeting Siglec-8/Siglec-F to Reduce Allergic Responses in vitro and in vivo", funded from 07/01/07-06/30/12 with an ARRA supplement from 07/01/10-06/30/11. The overarching goals were to explore ligands for Siglec-8/-F, their functions, and the mechanisms by which they regulate eosinophilic and allergic responses. Since 2007, we have published 14 papers related to this award and have received five patents related to Siglec-8. The goal of the present application is to employ monoclonal antibodies (mAbs) and glycan ligands for Siglec-8 in highly translational, preclinical in vitro and murine studies (including Siglec-8 trangenics) to define their utility as therapeutic targets. Innovations include liposomal targeting to reduce systemic toxicity of payload drugs by selectively targeting Siglec-8/-F bearing cells, thus reducing total dose of drug delivered. Approaches proposed involve use of nanoparticles for imaging of esophageal eosinophilic inflammation (Aim 1), liposomal delivery of inhibitory drugs selectively to eosinophils or mast cells by targeting Siglec-8/-F and its ligands to treat allergic and inflammatory diseases involving these cells (Aim 2), and use of Siglec-8/-F targeting liposomes carrying chemotherapies or our Siglec-8 mAb to treat malignant diseases involving eosinophils and mast cells (Aim 3).