Translational Control in IPF

描述（由申请人提供）：纤维增生性疾病是常见的、进行性的和现有治疗难治性的。来源于纤维增生性病变的成纤维细胞表现出一种无法解释的生长和生存信号的自主性。在这个修订后的提案中，我们建议研究特发性肺纤维化（IPF）患者的肺成纤维细胞，这是一种原型纤维增生性疾病，并利用我们最近在癌症生物学方面的发现作为指导，阐明自主功能的机制。在对人类乳腺癌的研究中，我们发现自主性是通过解除帽依赖性翻译起始机制（称为eIF 4F）的调节而获得的。在正常细胞中，eIF 4F接收来自基质和生长因子受体及其下游中间体的信号，并将这些输入协调成生理生长反应。在癌细胞中，eIF 4F用于整合和放大来自过多生长相关基因的多种生长和存活信号，以赋予自主性。在这里，我们展示了初步数据，表明eIF 4F的异常激活是IPF成纤维细胞的一种特性;在缺乏生长因子的情况下，激活成纤维细胞中的eIF 4F刺激细胞周期进入;基因工程改造缺乏eIF 4F负调节因子的小鼠具有夸大的纤维化反应。因此，我们假设，调控细胞周期转换的转录本的翻译控制失调是导致纤维化的原因;并提出了2个具体目标来验证这一假设：具体目标1：将IPF成纤维细胞中显示翻译效率协调变化的转录本分类为基于共同化学和生物学特征的离散组。A.化学：包含已知或候选RNA调控元件的核苷酸序列。B。生物学：免疫功能。具体目标二：关注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减弱IPF成纤维细胞增殖自主性。A.已知的调节元件。B。新发现的调节元件。如果成功的话，我们的研究将精确地识别基因表达翻译步骤中的紊乱，赋予IPF成纤维细胞增殖自主性，从而揭示肺和其他器官抗纤维化治疗的新分子靶点。公共卫生相关性。许多人类疾病的特征在于瘢痕组织积累，其导致器官功能障碍和死亡。瘢痕，也称为纤维化，可以影响许多不同的器官，包括肺，肝，肾，心脏，脉管系统和皮肤;并且通常很难治疗。在这里，我们建议研究产生瘢痕组织的细胞，成纤维细胞，在一种致命的肺瘢痕形成形式，在美国折磨超过35，000人，称为特发性肺纤维化（IPF）。我们的初步实验指出，产生蛋白质的细胞机制的异常激活，其模式与癌症中所见的相似。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被蛋白质合成机制的异常以导致肺纤维化的方式重新定向。这一信息有可能通过揭示抗纤维化治疗的新分子靶点，为所有瘢痕性疾病提供新的治疗方法。

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.