Signaling Pathway of IL-1Beta Induced TGFBeta Activation

描述(申请人提供)：IL-1β和TGFβ是参与肺纤维化和急性肺损伤(ALL)的细胞因子。IL-1β在大鼠肺内的瞬时过表达可导致肺纤维化，并导致肺泡灌洗液中活性TGFβ水平持续升高，提示转化生长因子(TGF)的激活可能是IL-1β的下游效应。上皮特异的αvbeta6整合素通过激活转化生长因子β来调节纤维化和ALL。我们实验室的初步研究表明，依赖于Alphavbeta6的TGFbeta激活受粘着斑激酶(FAK)、PI3激酶和Rho家族小GTP酶的调节，所有这些信号分子都参与了IL-1β信号转导。体外培养的大鼠肺泡上皮细胞经IL-1β刺激后，通过αvbeta6整合素激活TGFβ。我们的主要假设是，IL-1β在体外的刺激通过涉及FAK、PI3K和Rho家族的小GTP酶的信号级联导致依赖于β6的TGFbeta的激活。此外，我们假设IL-1通过依赖于β6的转化生长因子β激活而在体内诱导小鼠肺纤维化。为了确定这一信号级联，我们将在我们的大鼠肺泡上皮细胞体外模型中使用药物抑制剂和腺病毒转移FAK、PI3K、rac1和RhoA的结构性活性和显性负性基因结构。为了阐明依赖于β6的转化生长因子β激活在IL-1β诱导的肺纤维化中的体内作用，我们将在对照组、β6缺失(-/-)小鼠和αvbeta6阻断抗体预处理的小鼠的肺中瞬时过表达IL-1β，并评估肺纤维化的程度。这些研究应该有助于深入了解肺纤维化和ALI的途径，同时确定这些常见肺部疾病的新治疗靶点。

DESCRIPTION (provided by applicant): IL-1beta and TGFbeta are cytokines involved in pulmonary fibrosis and acute lung injury (ALl). Transient overexpression of IL-1beta in rat lungs induces pulmonary fibrosis associated with persistently elevated active TGFbeta levels in bronchoalveolar lavage samples, suggesting that TGF( activation can be a downstream effect of IL-1beta. The epithelial specific alphavbeta6 integrin regulates fibrosis and ALl by activating TGFbeta. Preliminary studies from our laboratory show that alphavbeta6-dependent TGFbeta activation is regulated by focal adhesion kinase (FAK), PI3 kinase, and the Rho family of small GTPases, all signaling molecules that are involved in IL-1beta signaling. Rat alveolar epithelial cells cultured in vitro activate TGFbeta through the alphavbeta6 integrin after stimulation with IL- 1beta. Our main hypothesis is that IL-1beta stimulation in vitro results in beta6-dependent TGFbeta activation through a signaling cascade involving FAK, PI3K and the Rho family of small GTPases. In addition, we hypothesize that IL-1( induces pulmonary fibrosis in mice in vivo by beta6-dependent TGFbeta activation. To identify this signaling cascade we will use pharmacological inhibitors and adenoviral transfer of constitutively active and dominant negative gene constructs of FAK, PI3K, Rac1, and RhoA in our in vitro model of rat alveolar epithelial cells. To elucidate the in vivo role of beta6-dependent TGFbeta activation in IL-1beta induced pulmonary fibrosis, we will transiently over-express IL- 1beta in the lungs of control, beta6 null (-/-) mice, and mice pre-treated with alphavbeta6 blocking antibody and assess the extent of pulmonary fibrosis. These studies should provide insight into the pathway involved in lung fibrosis and ALI while identifying new therapeutic targets for these common lung disorders.