Regulation of TGF-B1 Production and Signaling by Pin-1

除了间歇性、可逆性阻塞外，一些哮喘患者还会出现已知的固定性呼吸道阻塞 作为改建。越来越多的文献表明，TGFpt是由激活的和长期存活的呼吸道和 实质嗜酸性粒细胞(EOS)诱导细支气管成纤维细胞、平滑肌和 肌上皮细胞最终增加胶原蛋白和细胞外基质蛋白的产生。 当嗜酸性粒细胞从呼吸道中清除时，重塑减少，这表明抑制 Eos衍生的TGFpl或在细胞靶点阻断其促纤维化信号可能具有治疗效果。 最近，我们发现了PPIase(PPIase)参与了转化生长因子(31)的产生 和信号。Pin1与亲环素A和FKBP有关，是已知的唯一与之结合的真核酶 并催化磷酸丝氨酸-脯氨酸或磷酸苏氨酸-脯氨酸多肽的顺反异构化 债券。靶蛋白的异构化改变了它们的构象、功能或稳定性。Pin1最近 与GM-CSF mRNA代谢有关，提示在细胞因子的调节中发挥更广泛的作用 活化的EOS的生物发生。我们现在提出的证据是Pin1通过EOS和TGFp1调节TGFp1的表达 成纤维细胞中的TGFp1信号转导。特异性阻断EOS降低的TGFpl mRNA中Pinvs PPIase活性 稳定，导致稳定状态的mRNA水平和蛋白表达显著下降。 免疫沉淀研究表明，Pint与多种蛋白质结合，这些蛋白质与 调控TGFp1基因的衰退或表达。Pin1抑制减少胶原mRNA的积聚 TGFp1作用于体外培养的支气管气道源性成纤维细胞和呼吸道、支气管肺泡 体内治疗过敏性哮喘大鼠模型的灌洗(BAL)细胞和肺实质。因此，我们 假设Pin1是一种关键的信号中间体，在PIN1的产生和作用中发挥关键作用 哮喘肺组织中TGFp1的表达。因此，我们建议：1.确定Pin1异构酶活性是如何调节的 嗜酸性粒细胞激活后，2.确定Pin1蛋白靶向Hur和AUF1如何调控TGFp1 mRNA 衰变，3.确定Pin1如何调节成纤维细胞中的TGFp1信号和4，确定Pin1是否阻断 可以改变慢性过敏原暴露动物模型的呼吸道重塑。总而言之，这些研究将 阐明Pin1在哮喘发病机制和气道重塑中的作用和功能。

In addition to intermittent, reversible obstruction, some asthmatics, develop fixed airway obstruction known as remodeling. A growing literature suggests thatTGFpt produced by activated and long-lived airway and parenchymal eosinophils (EOS) induces hyperplasia of bronchiolar fibroblasts, smooth muscle and myoepithelial cells culminating with enhanced production of collagens and extracellular matrix proteins. Remodeling is reduced when eosinophils are eliminated from the airways suggesting that suppression of EOS derived TGFpl or blockade of its profibrotic signaling in cellular targets could have therapeutic benefits. Recently, we have identified Pin1, a peptidyl-prolyl isomerase (PPIase) as a participant in TGF(31 production and signaling. Pin1 is related to cyclophilin A and FKBP and is the only known eukaryotic enzyme that binds to and catalyzes the cis-trans isomerization of phosphoserine-proline or phosphothreonine-proline peptide bonds. The isomerization of target proteins alters their conformation, function or stability. Pin1 has recently been implicated in GM-CSF mRNA metabolism, suggesting a broader role in the regulation of cytokine biogenesis by activated EOS. We now present evidence that Pin1 regulates TGFpl expression by EOS and TGFpl signaling in fibroblasts. Specific blockade of PinVs PPIase activity in EOS reduced TGFpl mRNA stability, causing steady state mRNA levels and protein expression to significantly decline. Immunoprecipitation studies revealed that Pint binds to multiple proteins that have been implicated in the regulation of TGFpl mRNA decay or gene expression. Pin1 inhibition reduced collagen mRNA accumulation in bronchial airway derived fibroblasts exposed to TGFpl in vitro as well as in the airways, bronchoalveolar lavage (BAL) cells and lung parenchyma of allergic rat models of asthma treated in vivo. Therefore, we hypothesize that Pin1 is a critical, signaling intermediate that plays a key role in the production and action of TGFpl in the asthmatic lung. We therefore propose to: 1. Identify how Pin1 isomerase activity is regulated after eosinophil activation, 2. Determine how Pin1 protein targets HuR and AUF1 control TGFpl mRNA decay, 3. Determine how Pin1 regulates TGFpl signaling in fibroblasts and 4, Determine if Pin1 blockade can alter airway remodeling in animal models of chronic allergen exposure. In aggregate these studies will clarify the role and function of Pin1 in asthma pathogenesis and airway remodeling.