Lymphatic pumping and lymphatic transport of antigen to lymph node

淋巴泵和淋巴运输抗原至淋巴结

• 批准号: RGPIN-2015-03641
• 负责人: Liao, Shan
• 金额: $ 2.4万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=612474
• 关键词: Lymphatic; pumping; lymphatic; transport; antigen

Lymphatic vessels play essential roles in maintaining fluid balance and facilitating immune defense. While the heart beats to drive blood circulation, lymph transport primarily relies on lymphatic vessel pumping. Lymphatic pumping is driven by lymphatic smooth muscle cell (SMC) contraction. The function of lymphatic pumping is to propel lymph and cells transport to the draining lymph node (LN). When antigen and dendritic cells reach the draining lymph node (LN) through afferent lymphatic vessels, they must exit the vessels and migrate deep into the LN to activate T cell responses. However, it is not clear how changes in lymph flow may affect antigen delivery and antigen presentation in LN. In my previous studies, I have developed an intravital imaging model to study lymphatic pumping in mice. Using this model, I demonstrated that nitric oxide (NO) is required to maintain lymphatic pumping in physiological condition via the activation of the endothelial-derived nitric oxide synthase (eNOS). In contrast, the inducible nitric oxide synthase (iNOS) is responsible for the inhibition of lymphatic pumping in oxazolone skin sensitization induced inflammation (OX-inflammation). We hypothesize that NO regulates lymphatic pumping, which consequently modulates lymph flow velocity and flow pattern, and affect antigen delivery in lymph node. OBJECTIVES Objective 1. To determine how NO regulates lymphatic SMC to control lymphatic pumping. We will study if NO directly signals on SMCs to cause SMC relaxation or via indirectly interrupt SMC and lymphatic endothelial cell (LEC) interaction. We will use eNOS-/- mice, or broad NOS inhibitor L-NMMA or iNOS-/- mice to block NOSs and study how lymphatic SMCs are regulated in physiological and OX-inflammation.  Objective 2. To determine how lymphatic pumping controls the lymph flow velocity and flow pattern. We will measure the lymph flow in wild type, eNOS-/- and iNOS-/- mice in physiological and inflammatory conditions. We will study how lymph flow regulated LEC gene expression with cell culture using flow chamber to manipulate lymph flow velocity and flow pattern in variant conditions. Objective 3. To determine how lymphatic pumping manipulates antigen delivery to the draining LN. Free form of small antigens travel along the LN conduit system and are quickly captured by lymph node resident dendritic cells (DCs). We will use fluorescently labeled ovabulmin as small antigen to measure the antigen delivery in the draining LN when lymphatic pumping is impaired in variant conditions. We will study how these changes will alter the efficiency of antigen capture by LN DCs and initiation of T cell responses. The long-term goal of my studies will address fundamental questions of lymphatic pumping and lymphatic transport of antigen to the draining lymph node in order to efficiently present antigen and generate immune defense.

淋巴管在维持体液平衡和促进免疫防御方面起着重要作用。当心脏跳动驱动血液循环时，淋巴运输主要依靠淋巴管泵送。淋巴泵送是由淋巴平滑肌细胞（SMC）收缩驱动的。淋巴泵送的功能是推动淋巴和细胞运输到引流淋巴结（LN）。当抗原和树突状细胞通过传入淋巴管到达引流淋巴结（LN）时，它们必须离开淋巴管并深入LN以激活T细胞反应。然而，目前尚不清楚淋巴流动的变化如何影响LN中抗原的传递和递呈。在我之前的研究中，我开发了一种活体成像模型来研究小鼠的淋巴泵。使用该模型，我证明了生理状态下需要一氧化氮（NO）通过激活内皮源性一氧化氮合酶（eNOS）来维持淋巴泵送。相反，诱导型一氧化氮合酶（iNOS）负责在恶唑酮皮肤致敏诱导炎症（ox -炎症）中抑制淋巴泵送。我们假设NO调节淋巴泵送，从而调节淋巴流速和流动模式，并影响抗原在淋巴结中的传递。