Myeloid regulatory cells in allergic airway inflammation

描述（由申请人提供）：假设：髓系衍生调节细胞（MDRC），在过敏性气道炎症反应（如哮喘）期间募集到肺部，通过调节活性自由基（包括一氧化氮（NO）和超氧化物（02-））的生物利用度来帮助控制组织炎症水平。具体目的：(1)验证致敏小鼠在抗原攻击后，募集到肺部的髓系亚群在变应性气道炎症中产生并调节反应性自由基的临界平衡的假设(2)在小鼠模型中确定MDRC是否通过反应性自由基物种的机制减轻哮喘炎症反应。实验方法：将C57BL/6、INOS-/-或B6 (Cg)- ncf1m1 J/J小鼠腹腔致敏，并用鼻内抗原卵清蛋白（OVA）刺激。支气管肺泡灌洗液和肺组织将被检查：(1)MDRC募集的动态(2)MDRC的功能，包括吞噬能力，以及MDRC产生的细胞因子和自由基。此外，我们将研究(3)MDRC是否在体外通过iNOS、精氨酸酶或NADPH氧化酶途径介导T细胞增殖抑制；(4)MDRC是否在体内过继转移后介导T细胞增殖抑制，以及NO和02-在这一作用中的作用；(5)过继转移的MDRC是否在气道炎症模型中调节气道的高反应性。理由：在过敏性气道炎症反应中，先天细胞在适应性免疫细胞之前被招募到肺部。我们提供的初步数据显示：(1)产生O2-和NO的MDRC的两个亚群被招募到肺部，(2)MDRC通过依赖自由基的机制抑制T细胞增殖，表明这些细胞在体内具有减轻炎症的潜力。与公共卫生和NHLBI使命的相关性：拟议的研究将直接测试MDRC抑制哮喘疾病严重程度的潜力，潜在地确定抗哮喘治疗的新靶点。

DESCRIPTION (provided by applicant): Hypothesis: Myeloid derived regulatory cells (MDRC), recruited to the lung during allergic airway inflammatory responses such as asthma, help to control the level of tissue inflammation by regulating the bioavailability of reactive free radicals, including nitric oxide (NO) and superoxide (02-). Specific Aims: (1) To test the hypothesis that myeloid subpopulations recruited to the lung of sensitized mice following antigen challenge generate and regulate the critical balance of reactive free radicals during allergic airway inflammation (2) Determine whether MDRC attenuate the asthmatic inflammatory response by mechanisms using reactive free radical species in a mouse model. Experimental Approach: C57BL/6, INOS-/- or B6 (Cg)-Ncf1m1 J/J mice will be sensitized intraperitoneally and challenged with the intranasal antigen, ovalbumin (OVA). Bronchoalveolar lavage (BAL) fluid and lung tissue will be examined for (1) dynamics of recruitment of MDRC (2) function of MDRC including phagocytic ability, and generation of cytokines and free radical species by MDRC. In addition, we will investigate (3) whether MDRC mediate suppression of T cell proliferation in vitro via iNOS, Arginase or NADPH oxidase pathways (4) whether MDRC mediate suppression of T cell proliferation following adoptive transfer in vivo and the role of NO and 02- in this effect, and (5) whether the adoptively transferred MDRC modulate airway hyper-responsiveness in a model of airway inflammation. Rationale: During allergic airway inflammatory responses, innate cells are recruited to the lung prior to adaptive immune cells. We present preliminary data to show (1) that two subsets of MDRC which generate O2- and NO are recruited to the lungs, and (2) MDRC suppress T cell proliferation via mechanisms that depend on free radicals, suggesting the potential for these cells to attenuate inflammation in vivo. Relevance to Public Health and the NHLBI Mission: The proposed studies will test directly the potential of MDRC to suppress asthma disease severity, potentially identifying novel targets for anti-asthmatic therapy.