TGF Beta Receptor Dynamics

项目主任/首席调查员(Last，RRST，Midate)：Leof，Edward，B 项目摘要(请参阅说明)： 转化生长因子β(TGF-β)生物学中的一个中心悖论是，相同的生长因子如何能够 诱导诸如生长刺激(即，间充质细胞)和生长抑制(即， 上皮细胞)？考虑到转化生长因子-β在许多正常和病理条件下的关键作用， 如果我们希望制定具体的干预战略，解决这一问题是至关重要的。为此，我们 一直在研究一般假设，即细胞对转化生长因子的反应依赖于 交通和信号机械的综合作用。为了支持这项提议，我们已经 结果表明：(1)在极化的上皮细胞中，转化生长因子-β受体进入基底区，毗邻 连接复合体；(Ii)哺乳动物逆转录复合体特异性地维持II型转化生长因子-β受体 通过细胞骨架蛋白、EEA1和EPA1控制内体循环到质膜递送的极性 Rab11阳性区段；(Iii)已知的运输蛋白SNX9在 转化生长因子-β在其典型的血浆膜蛋白作用下游的信号传递；(Iv)一种独特的机制 确定转化生长因子-β信号通路中的哪些特异性可以被控制并随后被利用来治疗 依赖于Smad3的疾病；(V)促纤维化的转化生长因子-β反应需要PDGF的协同作用 和ErbB受体酪氨酸激酶；以及，最重要的是，(Vi)利用肺纤维化的治疗模型， 提供临床前数据，证明肺功能的生理参数可以通过 靶向多种转化生长因子-β调控通路。我们建议使用各种不同的方法来扩展这些发现 生化、生物和遗传方法。第一，控制受体元件和细胞因子 将定义转化生长因子-β受体的运输以及逆转录聚体在转化生长因子-β刺激的EMT/迁移中的作用。 因为许多疾病是由蛋白质分类或运输到特定细胞的能力缺陷引起的 地点，特征的运作反式作用因子提供了潜在的机制，以改变细胞 对转化生长因子-β的反应。第二，SNX9在调节包括肺在内的Smad3依赖表型中的作用 纤维化和胶质母细胞瘤的进展将被确定。在世界上超过45%的死亡人数中 患有慢性纤维增生性疾病的人，中位数 目前放化疗的胶质母细胞瘤的无进展和SUN/IVAL分别为~7和15个月。 分别而言，显然需要新的方法。 相关性(请参阅说明)： 转化生长因子-β是一种对人体健康有益或有害的蛋白质。虽然它刺激细胞的能力 生长对伤口的正常愈合很重要，如果不加检查，许多器官的功能可能会 因疤痕(即纤维化)的形成而中断。相反，转化生长因子-β的生长抑制作用在 预防癌症。拟议的研究将确定/表征可用于提高 或减少这些re.sDnns值。

ProgramDirector/PrincipalInvestigator(Last,Rrst,Middle):Leof,Edward,B PROJECT SUMMARY (See Instmctions): A central paradox in transforming growth factor beta (TGF-p) biology is how the same growth ^ctor can induce such divergent responses as growth stimulation (i.e., mesenchymal cells) and growth inhibition (i.e., epithelial cells)? Considering the pivotal role TGF-^ has in a number of nomial and pathological conditions, addressing that issue is fundamental if we hope to develop specific intervention strategies. To that end, we have been investigating the general hypothesis that the cellular response to TGF-¿ is dependent upon an integrated action ofthe trafficldng and signaling machinery. In support of that proposal, we have detemiined that (i) in polarized epithelial cells TGF-p receptors traffic to the basolateral domain, adjacent to the junctional complex; (ii) the mammalian retromer complex specifically maintains type II TGF-p receptor polarity by controlling recycling endosome to plasma membrane delivery by way of clathrin, EEA1 and Rab11 positive compartments; (iii) sorting nexin 9 (SNX9), a known trafficking protein, has a new role in TGF-p signaling downstream of its canonical plasma membriane action; (iv) an unique mechanism has been defined by which specificity in TGF-p signaling can be controlled and subsequently exploited to treat diseases dependent upon Smad3; (v) profibrotic TGF-p responses require the cooperative action of PDGF and ErbB receptor tyrosine kinases; and, most importantly, (vi) utilizing a treatment model of lung fibrosis, provided preclinical data documenting that physiologic parameters of lung function can be stabilized by targeting multiple TGF-p regulated pathways. We propose to extend these findings using a variety of biochemical, biological, and genetic approaches. First, the receptor elements and cellular factors controlling TGF-p receptor trafficking as well as the role of retromer in TGF-p stimulated EMT/migration will be defined. As a number of diseases result from defects in the ability to sort or transport proteins to defined cellular locales, characterizing the operative trans-acting factors provides potential mechanisms to alter the cellular response to TGF-p. Second, the role of SNX9 in regulating Smad3-dependent phenotypes including lung fibrosis and glioblastoma progression will be determined. In that upwards of 45% of all deaths in the developed wortd are attributed to some sort of chronic fibroproliferative disorder, and the median progression-free and sun/ival for glioblastoma with current chemoradiation is ~7 and 15 months, respectively, new approaches are clearly needed. RELEVANCE (See instructions): TGF-p is a protein that can be either helpful or harmful to human health. While its ability to stimulate cell growth is important for normal wound healing, when unchecked the function of many organs can be disrupted by scar (i.e., fibrosis) formation. Conversely, the growth inhibitory actions of TGF-p are critical in preventing cancer. The proposed studies will identify/characterize targets that can be used to either increase or decrease these re.sDnnses.