Translational Control in IPF

描述(由申请人提供)：纤维增生性疾病是一种常见的、进行性的疾病，对现有的治疗方法难以奏效。来自纤维增生性病变的成纤维细胞表现出对生长和生存信号的不明原因的自主性。在这个修订的方案中，我们建议研究特发性肺纤维化(IPF)患者的肺成纤维细胞，并以我们在癌症生物学方面的最新发现为指导，阐明自主功能的机制。在对人类乳腺癌的研究中，我们发现自主是通过解除对帽依赖的翻译启动机制eIF4F的调控来授予的。在正常细胞中，eIF4F从基质和生长因子受体及其下游中间体接收信号，并将这些输入协调成生理生长反应。在癌细胞中，eIF4F用于整合和放大多种生长和生存信号，这些信号来自过多的生长相关基因，以赋予自主性。在这里，我们展示的初步数据表明，eIF4F的异常激活是IPF成纤维细胞的一种特性；在没有生长因子的情况下，在成纤维细胞中激活eIF4F会刺激细胞周期进入；缺乏eIF4F负调控因子的基因工程小鼠具有夸大的纤维化反应。因此，我们假设，调控细胞周期转运的转录本的非调控翻译控制存在于纤维化的原因路径上；并提出了两个特定的目标来检验这一假说：特定的目标1：基于共同的化学和生物学特征，将显示翻译效率协调变化的IPF成纤维细胞中的转录本分类为不同的组。A.化学：由已知或候选的RNA调节元件组成的核苷酸序列。B.生物学：指定的功能。具体目标2：专注于编码细胞周期调节因子的转录本，确定干扰调节元件功能是否会削弱IPF成纤维细胞的增殖自主性。答：已知的监管要素。B.新发现的调控因素。如果成功，我们的研究将准确地识别赋予IPF成纤维细胞增殖自主性的基因表达翻译步骤的错乱，从而揭示肺和其他器官抗纤维化治疗的新的分子靶点。与公共卫生相关。许多人类疾病的特点是疤痕组织堆积，导致器官功能障碍和死亡。疤痕形成，也称为纤维化，可以影响到许多不同的器官，包括肺、肝、肾、心脏、血管和皮肤；而且通常很难治疗。在这里，我们建议研究产生疤痕组织的细胞-成纤维细胞，这是一种致命的肺疤痕形成形式，在美国困扰着超过3.5万人，称为特发性肺纤维化(IPF)。我们的试点实验指出，产生蛋白质的细胞机制异常激活，与癌症的模式相似。我们在这项研究中的目标是了解成纤维细胞的生物学如何通过蛋白质合成机制的异常而改变方向，从而导致肺纤维化。通过揭示抗纤维化治疗的新分子靶点，这些信息有可能导致所有疤痕疾病的新治疗。

DESCRIPTION (provided by applicant): Fibroproliferative disorders are common, progressive and refractory to available therapy. Fibroblasts derived from fibroproliferative lesions manifest an unexplained autonomy for growth and survival signals. In this revised proposal, we propose to study lung fibroblasts from patients with Idiopathic Pulmonary Fibrosis (IPF), a prototype fibroproliferative disease, and elucidate the mechanism of autonomous function using our recent discoveries in cancer biology as a guide. In studies of human breast carcinoma, we discovered that autonomy is conferred by deregulation of the cap-dependent translation initiation machinery, designated eIF4F. In normal cells, eIF4F receives signals from matrix and growth factor receptors and their downstream intermediates, and orchestrates these inputs into a physiological growth response. In cancer cells, eIF4F serves to integrate and amplify diverse growth and survival signals emanating from a plethora of growth-related genes to confer autonomy. Here we show preliminary data indicating that aberrant activation of eIF4F is a property of IPF fibroblasts; that activating eIF4F in fibroblasts stimulates cell cycle entry in the absence of growth factors; and that mice genetically engineered to lack negative regulators of eIF4F have an exaggerated fibrotic response. We therefore hypothesize that deregulated translational control of transcripts governing cell cycle transit lies on the causal pathway to fibrosis; and propose 2 specific aims to test this hypothesis: Specific Aim 1: Classify transcripts in IPF fibroblasts that display coordinate changes in translational efficiency into discrete groups based on shared chemical and biological characteristics. A. Chemical: Nucleotide sequences that comprise known or candidate RNA regulatory elements. B. Biological: Assigned function. Specific Aim 2: Focusing on transcripts encoding cell cycle regulators, determine whether disrupting regulatory element function attenuates IPF fibroblast proliferative autonomy. A. Known regulatory elements. B. Newly discovered regulatory elements. If successful, our studies will precisely identify derangements in the translational step of gene expression that confer IPF fibroblasts with proliferative autonomy, thus revealing new classes of molecular targets for antifibrotic therapy in the lung and other organs. PUBLIC HEALTH RELEVANCE. Many human diseases are characterized by scar tissue accumulation that leads to organ dysfunction and death. Scarring, also called fibrosis, can affect many different organs including the lung, liver, kidney, heart, vasculature and skin; and is often very difficult to treat. Here we propose to study the cell producing scar tissue, the fibroblast, in a deadly form of lung scarring that afflicts more than 35,000 people in the US, termed idiopathic pulmonary fibrosis (IPF). Our pilot experiments point to abnormal activation of the cellular machinery that produces protein, in a pattern similar to that seen in cancer. Our goal in this study is to understand how the biology of fibroblasts can be redirected by abnormalities in the protein synthesis machinery in a manner that leads to lung fibrosis. This information has the potential to lead to new treatments for all scarring diseases by revealing new molecular targets for antifibrotic therapy.