Regulation of Allergic Asthma by TGF-beta-induced Modulation of mMCP-1 and mMCP-4

描述(由申请人提供)：转化生长因子-β(转化生长因子-β)与过敏性哮喘的发展密切相关。肥大细胞脱颗粒也在加重过敏性哮喘中起关键作用，是白三烯拮抗剂和抗IgE抗体的治疗靶点。我们实验室的最新数据表明，缺乏调节转化生长因子-β活性的αvβ6整合素的小鼠，可以免受呼吸道高反应性的影响。此外，这种作用是通过转化生长因子-β诱导肥大细胞不同的蛋白表达，即通过上调mMCP-1和下调mMCP-4来实现的。这些蛋白水解酶已被证明影响呼吸道的高反应性，mMCP-1增强对乙酰甲胆碱引起的平滑肌收缩，而mMCP-4抑制IL-13诱导的收缩。在这项研究中，我们将使用平行实验系统(肌浴中的气管环收缩和肺切片中的气道狭窄)系统地研究mMCP-1和mMCP-4影响收缩反应的机制。我们将使用mMCP-1-和mMCP-4-基因敲除小鼠的结构来评估转化生长因子-β与肥大细胞的相互作用对收缩反应的贡献。我们建议确定mMCP-1和mMCP-4是直接作用于平滑肌还是通过邻近的上皮细胞间接作用。由于肌力的产生依赖于钙离子依赖的肌动蛋白-肌球蛋白的交叉桥联，我们还将研究mMCP-1和mMCP-4是如何调节钙稳态的。这些研究将阐明转化生长因子-β调控肥大细胞蛋白水解酶mMCP-1和mMCP-4表达影响气道高反应性的机制。由于这一途径在过敏性哮喘的发病机制中起着重要作用，对其更深入的了解将为未来的治疗提供潜在的靶点。

DESCRIPTION (provided by applicant): Transforming growth factor-beta (TGF-beta) has been strongly implicated in the development of allergic asthma. Mast cell degranulation also plays a key role in exacerbating allergic asthma, and is the therapeutic target of both leukotriene antagonists and anti-IgE antibodies. Recent data from our laboratory has suggested that mice lacking the alpha v beta6 integrin, which modulates TGF-beta activity, are protected from airway hyperreactivity. Furthermore, this effect is mediated by differential mast cell protease expression induced by TGF-beta, namely via the upregulation of mMCP-1 and the downregulation of mMCP-4. These proteases have been shown to influence airway hyperreactivity, with mMCP-1 augmenting smooth muscle contraction in response to methacholine and mMCP-4 inhibiting IL-13 induced contraction. In this proposal we will systematically investigate the mechanism by which mMCP-1 and mMCP-4 affect contractile response using parallel experimental systems (tracheal ring contraction in muscle bath and airway narrowing in lung slices). We will use constructs of mMCP-1-, and mMCP-4- knockout mice to assess what contribution the interaction of TGF-beta with mast cells makes to the contractile response. We propose to determine whether mMCP-1 and mMCP-4 act directly on smooth muscle or indirectly via adjacent epithelial cells. Since force generation in smooth muscle depends on Ca2+-dependent actin-myosin cross-bridging, we will also investigate how mMCP-1 and mMCP-4 modulate Ca2+ homeostasis. The proposed studies will elucidate the mechanism by which TGF-beta-modulated expression of mast cell proteases mMCP-1 and mMCP-4 affect airway hyperreactivity. As this pathway plays an important role in the pathogenesis of allergic asthma, a more thorough understanding will provide potential targets for future therapy.