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（AL 1）的细胞因子。IL-1 β在大鼠肺中的瞬时过表达诱导肺纤维化，与支气管肺泡灌洗样品中活性TGF β水平的持续升高相关，表明TGF β活化可能是IL-1 β的下游效应。上皮特异性α v β 6整联蛋白通过激活TGF β调节纤维化和AL 1。我们实验室的初步研究表明，α v β 6依赖性TGF β激活受粘着斑激酶（FAK）、PI 3激酶和Rho小GTP酶家族的调节，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在IL-1 β刺激后通过α v 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、PI 3 K和Rho家族的小GTP酶的信号级联导致β 6依赖性TGF β活化。此外，我们假设IL-1 β通过β 6-依赖性TGF β激活在体内诱导小鼠肺纤维化。为了鉴定这种信号级联，我们将在大鼠肺泡上皮细胞的体外模型中使用药理学抑制剂和FAK、PI 3 K、Rac 1和RhoA的组成性活性和显性负性基因构建体的腺病毒转移。为了阐明β 6依赖性TGF β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、β 6缺失（-/-）小鼠和用α v β 6阻断抗体预处理的小鼠的肺中瞬时过表达IL-1 β，并评估肺纤维化的程度。这些研究应能深入了解肺纤维化和ALI的相关途径，同时为这些常见肺部疾病确定新的治疗靶点。

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.