Signaling Pathway of IL-1Beta Induced TGFBeta Activation

描述（由申请人提供）：il -1 β和tgf β是参与肺纤维化和急性肺损伤（ALl）的细胞因子。大鼠肺中il -1 β的短暂过表达可诱导肺纤维化，并与支气管肺泡灌洗样品中活性TGF - β水平持续升高相关，提示TGF(激活可能是il -1 β的下游效应。上皮特异性的alphavbeta6整合素通过激活tgf β来调节纤维化和ALl。我们实验室的初步研究表明，依赖于α - β 6的tgf - β激活是由局灶黏附激酶（FAK）、PI3激酶和Rho家族的小GTPases调控的，所有这些信号分子都参与il -1 - β信号传导。体外培养的大鼠肺泡上皮细胞经IL- 1 β刺激后，通过α - β - 6整合素激活tgf - β。我们的主要假设是体外il -1 β刺激通过涉及FAK， PI3K和Rho家族小GTPases的信号级联导致β 6依赖性TGFbeta激活。此外，我们假设IL-1（）通过β 6依赖性tgf - β激活在体内诱导小鼠肺纤维化。为了确定这一信号级联，我们将在体外大鼠肺泡上皮细胞模型中使用药理学抑制剂和腺病毒转移FAK、PI3K、Rac1和RhoA的组成活性和显性阴性基因结构。为了阐明β - 6依赖性TGFbeta激活在IL-1 β诱导的肺纤维化中的体内作用，我们将在对照组、β - 6缺失（-/-）小鼠和经α - β - 6阻断抗体预处理的小鼠的肺中短暂过表达IL-1 β，并评估肺纤维化的程度。这些研究有助于深入了解肺纤维化和ALI的通路，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.