Lymphocyte Activation in Sickle Cell Lung Disease

描述(申请人提供)：我们已经发现CD1d限制的iNKT细胞，一个淋巴细胞亚群，通常代表1%的血淋巴细胞，在NY1DD镰状细胞小鼠的肺部炎症和损伤的传播中发挥核心作用。激活后，这些细胞释放干扰素和IL-2，从而刺激循环淋巴细胞产生干扰素诱导的趋化因子和CXCR3诱导。激动剂与腺苷A2a受体结合可抑制iNKT细胞的激活。我们已经证明，用抗CD1d抗体选择性地阻断iNKT细胞，使其枯竭，或者用腺苷A2AR激动剂治疗，可以显著减少NY1DD小鼠的基线肺部炎症和损伤。因此，我们通过证明具有不变T细胞受体(INKT)的NKT细胞是肺损伤的关键启动者，从而建立了镰状细胞性肺病的重要新范式。这一假设的核心假设是肺缺血后肺iNKT细胞的激活在通过CXCR3受体将腺苷敏感的炎症级联反应从iNKT传播到其他细胞中起关键作用，这些炎症反应是由干扰素和干扰素诱导的趋化因子CXCL9(MIG)和CXCL10(IP-10)引起的。具体目标1将：评估抑制iNKT细胞或其CXCR3介导的转运对A)基线肺炎症和损伤；B)缺氧-复氧造成的加重损伤(危象)的后果。假设：NKT细胞在维持持续的炎症级联反应中起中心作用，以应对持续性的局灶性肺缺血。INKT细胞引起广泛的白细胞向肺内转运，最终导致继发性肺损伤。阻断CD1d或CXCR3可减轻SCD肺损伤。特殊目的2将使用：A)淋巴细胞缺陷的NY1DD x Rag1-/-小鼠；B)NY1DD x A2AR-/-小鼠；以及C)NY1DD x CXCR3-/-小鼠，作为证实iNKT细胞、A2A受体和CXCR3在SCD肺损伤中的中介作用的手段。假设：SCD的肺损伤在很大程度上是由于依赖CXCR3的iNKT细胞募集，这些细胞是A2A激动剂的关键靶点。特异性目标3将评估小鼠和SCD患者血液中iNKT细胞的数量、激活状态和CXCR3的表达。患者的血液将从我们的合作者约书亚·菲尔德博士那里运来，他在华盛顿大学经营着成人SCD诊所。假设：SCD患者的iNKT细胞数量、CXCR3表达和细胞内干扰素水平升高，这将与疾病严重程度的一些参数相关。 公共卫生相关性：镰状细胞病(SCD)是美国最常见的遗传性血液病，影响约8万人(每600名非裔美国人中有1人)。它是由2-珠蛋白基因第六密码子的点突变引起的，导致谷氨酸残基被缬氨酸取代。SCD会导致多器官衰竭，但肺部特别容易受到损伤。我们发现，作为一个较小的淋巴细胞亚群，不变的NKT细胞在维持SCD的肺损伤中起着重要作用。我们建议研究这种细胞如何产生肺损伤，以及抑制其功能对肺损伤的影响。我们还将研究SCD患者血液中的iNKT细胞。

DESCRIPTION (provided by applicant): We have discovered that CD1d-restricted iNKT cells, a lymphocyte subset that normally represents < 1% of blood lymphocytes, plays a central role in propagating pulmonary inflammation and injury in the NY1DD sickle cell mouse. Upon activation, these cells release IFN and IL-2 which evoke the production of IFN-inducible chemokines and CXCR3 induction on circulating lymphcytes. iNKT cell activation is inhibited by agonist binding to adenosine A2A receptors. We have shown that selective blockade of iNKT cells with anti-CD1d antibodies, their depletion, or treatment with an adenosine A2AR agonist, significantly reduces substantial baseline pulmonary inflammation and injury in NY1DD mice. Thus, we have established an important new paradigm of sickle cell lung disease by showing that NKT cells that have an invariant T cell receptor (iNKT) are key initiators of lung injury. The central hypothesis of this proposal is that activation of pulmonary iNKT cells in response to lung ischemia plays a critical role in propagating an adenosine-sensitive inflammatory cascade from iNKT to other cells by IFN- and IFN-inducible chemokines, CXCL9 (MIG) and CXCL10 (IP-10) via CXCR3 receptors. Specific Aim 1 will: assess the consequences of inhibiting iNKT cells or their CXCR3-mediated trafficking on A) baseline pulmonary inflammation and injury; B) accentuated injury (crisis) produced by hypoxia-reoxygenation. Hypothesis: NKT cells play a central role in maintaining an ongoing inflammatory cascade in response to persistent focal lung ischemia. iNKT cells evoke generalized leukocyte trafficking to the lung that ultimately results in secondary lung injury. CD1d blockade or CXCR3 blockade will reduce lung injury in SCD. Specific Aim 2 will use: A) lymphocyte deficient NY1DD x Rag1 -/- mice; B) NY1DD x A2AR-/- mice; and C) NY1DD x CXCR3 -/- mice, as means of substantiating the roles of iNKT cells, A2A receptors and CXCR3 as mediators of lung injury in SCD. Hypothesis: Lung injury in SCD is due in large part to CXCR3-dependent iNKT cell recruitment and these cells are key targets of A2A agonists. Specific Aim 3 will assess blood iNKT cell numbers, activation state and CXCR3 expression in the blood of mice and patients with SCD. Patient blood will be shipped from our collaborator, Dr. Joshua Field, who runs the adult SCD clinic at Washington University. Hypothesis: Patients with SCD will have elevated iNKT cell numbers, CXCR3 expression and intracellular IFN that will be correlated to some parameters of disease severity. PUBLIC HEALTH RELEVANCE: Sickle cell disease (SCD) is the most common genetic hematological disorder in the United States, affecting about 80,000 people (1 of every 600 African Americans). It is caused by a point mutation in the sixth codon of the 2-globin gene, and results in replacement of a glutamic acid residue by valine. SCD leads to multi-organ failure, but the lungs are particularly susceptible to injury. We have discovered that a minor lymphocyte subset, invariant NKT cells play an important role in maintaining lung injury in SCD. We propose to investigate how this cells produces lung injury, and the effects of inhibiting its function on lung injury. We also will study iNKT cells in the blood of SCD patients.