Development of Robust Culture Systems for the Human Splenic Littoral Cell

描述（申请人提供）：脾脏是人体最大的次级免疫系统器官。无脾个体死于严重败血症的几率增加。他们患自身免疫性疾病、某些癌症和缺血性心脏病的风险也更大。增强的死亡率归因于缺乏隔离在脾脏中的吞噬细胞，其有效地消除适当的靶标，尽管在其他部位可以发现相关细胞。虽然脾白色髓的整体组织结构与淋巴结相似，但脾不与淋巴系统相连。相反，病原体、红细胞、凋亡/坏死、改变和肿瘤细胞都被递送到血液中并离开脾脏。与白色髓相反，脾红髓既作为储存器又作为过滤器，其决定在其中行进的细胞是否被保留、破坏或返回循环。人静脉窦衬里细胞，称为沿岸的细胞（LC），约占红髓的30%。越来越多的证据表明，这些高度特化的脾细胞是红细胞和其他细胞是否被破坏、保留或返回循环的主要决定因素，尽管调节其功能的机制完全未知。其他人和我们表明，LC不是经典的内皮细胞，因为它们携带多种巨噬细胞和平滑肌相关抗原，是CD 8+，缺乏内皮和造血谱系的传统标志物。那么，为什么对LC函数知之甚少呢？LC的获得、纯化和培养在历史上被证明是非常困难的。基于我们最近在获得新鲜脾以及鉴定区分LC与其他脾细胞的标志物方面的成功，我们现在准备进一步分离和分析LC基因/蛋白表达（AIM I）。虽然在复杂器官内形成特化结构的细胞（例如LC）通常难以离体繁殖，但克服这些限制将代表理解LC功能的重大进展。我们已经召集了一组专家内皮细胞生物学家，免疫学家和病理学家，他们将为我们提供深入的指导，因为我们开发了不同的LC培养系统（AIM II），这些系统既具有生理相关性又易于处理。这些方法将使得能够发现LC功能的基础机制，并导致能够在不同疾病状态（例如败血症、疟疾、血红蛋白病等）中调节脾过滤的治疗剂的开发。

DESCRIPTION (provided by applicant): The spleen is the largest secondary immune system organ in man. Individuals who are asplenic die at an increased rate from overwhelming sepsis. They are also at greater risk of autoimmune disease, some cancers and ischemic cardiac disease. Enhanced mortality is attributed to lack of phagocytes sequestered in spleen that efficiently eliminate appropriate targets, though related cells can be found at other sites. Although the overall organization of splenic white pulp is similar to that of lymph nodes, spleen is not connected to the lymphatic system. Instead, pathogens, RBCs, apoptotic/necrotic, altered and tumor cells all are delivered to and leave the spleen in blood. In contrast to white pulp, splenic red pulp serves as both a reservoir and a filter that determines whether cells coursing therein are retained, destroyed or returned to the circulation. The human venous sinus-lining cell, known as the littoral cell (LC), comprises ~30% of red pulp. Increasing evidence indicates these highly specialized splenocytes are the major determinant of whether RBCs and others are destroyed, retained or returned to the circulation, though the mechanisms that regulate their function are entirely unknown. Others and we showed that LCs are not a classical endothelial cells as they bear multiple macrophage and smooth muscle-associated antigens, are CD8+ and lack traditional markers of endothelial and also hematopoietic lineage. So, why is so little known about LC function? The acquisition, purification and culture of LCs have historically proved very difficult. Based on our recent success in obtaining fresh spleen as well as identifying markers that distinguish LCs from other splenocytes, we are now prepared to further isolate and profile LC gene/protein expression (AIM I). Although cells such as LCs that form specialized structures within complex organs are often hard to propagate ex vivo, overcoming these limitations would represent a significant advance in understanding LC function(s). We have assembled a group of expert endothelial cell biologist-immunologists, and pathologists who will provide us with in depth guidance as we develop diverse LC culture systems (AIM II) that are both physiologically relevant and tractable. These methods will enable discovery of the mechanisms that underlie LC function and lead to development of therapeutics able to modulate splenic filtration in different disease states (e.g. sepsis, malaria, hemoglobinopathies and others).