Changes in actin dynamics regulated by villin and gesolin are determinants of cell fate and may be key to gastrointestinal inflammatory disease

绒毛蛋白和地溶胶调节的肌动蛋白动力学变化是细胞命运的决定因素，可能是胃肠道炎症疾病的关键

• 批准号: 10238131
• 负责人: Seema Khurana
• 金额: $ 46.19万
• 依托单位: UNIVERSITY OF HOUSTON
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-20 至 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10238131
• 关键词: Actins; Autophagocytosis; Bacteria; Basic Science; Biosensor; Cell Death; Cell Line; Cell Survival; Cells; Cellular Stress; Cessation of life; Chronic; Clinical; Colitis; Colorectal Cancer; Complex; Crohn' s disease; Cytoskeleton; DNA Damage; Defect; Diagnosis; Disease; Disease model; Disease remission; Down-Regulation; Embryo; Epithelial Cells; Ethnic group; Eukaryotic Initiation Factors; Event; Exhibits; G Actin; Gelsolin; Gene Expression; Genes; Genetic Transcription; Genetic Translation; Goals; Growth; Guanosine Triphosphate Phosphohydrolases; Health; Health Care Costs; Histologic; Homeostasis; Human; Ileitis; Immunity; Incidence; Infection; Inflammation; Inflammatory; Inflammatory Bowel Diseases; Knockout Mice; Lead; Link; Mediating; Mind; Mitochondria; Modeling; Molecular; Mucositis; Mus; Nature; Organism; Orthologous Gene; Outcome; Pathogenesis; Pathway interactions; Patient Care; Patients; Pattern; Phosphorylation; Phosphotransferases; Physiological; Play; Prevalence; Prokaryotic Initiation Factor-2; Protein Biosynthesis; Protein phosphatase; Proteins; Recovery; Regulation; Relapse; Repression; Risk; Role; Sampling; Scientific Advances and Accomplishments; Signal Pathway; Signal Transduction; Stress; Techniques; Testing; Therapeutic; Transgenic Organisms; Translations; Up-Regulation; activating transcription factor 4; age group; base; biological adaptation to stress; cell injury; cost; gastrointestinal; improved; in vivo evaluation; inhibitor/antagonist; innovation; insight; intestinal epithelium; intestinal homeostasis; malignant small intestine tumor; mouse model; multiple myeloma M Protein; mutant; novel; novel therapeutics; overexpression; prevent; remediation; response; sensor; side effect; stressor; treatment strategy; villin

Regulation of mRNA translation is one of the most immediate cell response to any form of stress. It is initiated by stress sensing kinases, all of which phosphorylate the alpha subunit of eukaryotic translation initiation factor 2 (EIF2A). This results in repression of global protein synthesis but is accompanied by selective translation of proteins vital for cell survival and recovery from stress. To restore cellular homeostasis and to reverse EIF2A signaling, de-phosphorylation of EIF2A is regulated by protein phosphatase 1 (PP1) in complex with one of its regulatory subunits and globular actin (G-actin). G-actin therefore, limits PP1 activity although how cellular actin dynamics are modified to regulate PP1 activity is not known. EIF2A signaling increases translation of activating transcription factor 4 (ATF4) to promote expression of genes involved in stress remediation such as autophagy genes. Conversely, if the stress is unresolved ATF4 regulates the transcription of genes that promote cell death to eliminate damaged cells. The control switch that modulates the cells stress response between survival and death governs the initiation of most inflammatory diseases. In line with that, chronic activation of EIF2A signaling is associated with mucosal inflammation in patients with Crohn’s disease (CD). Despite this, the molecular basis of EIF2A signaling in intestinal epithelial cells (IECs) remains unidentified. We made the novel observation that the IEC actin cytoskeleton fulfils a general function as a biosensor of cell health and regulates EIF2A signaling to establish if the stressed cell will survive or die. We show that by regulating cellular actin dynamics, two homologous actin-severing proteins villin1 and gelsolin integrate stress signaling pathways with cell fate pathways. Using the villin1/gelsolin double knockout mice we show that when the crosstalk between the IEC actin cytoskeleton and EIF2A signaling does not function properly, chronic inflammation ensues. As a result, DKO mice develop spontaneous ileitis that resembles functionally, histologically and clinically human CD. Moreover, our studies with mouse models of CD and CD patient samples indicate that defects in the crosstalk between IEC actin cytoskeleton and EIF2A signaling could be a universal feature of CD. We propose that studying how these pathways normally function in the IECs and how they go awry can provide basic insight into events that drive CD pathogenesis but can also identify novel treatment strategies for CD. We present an innovative mechanistic approach using state-of-the-art techniques that combine the use of IEC lines, transgenic and validated mouse models of disease, and patient samples. The goal of the study is: (1) to characterize the molecular mechanism(s) by which the crosstalk between the actin cytoskeleton and stress signaling determines IEC fate; (2) to determine how defects in the crosstalk between actin cytoskeleton and stress signaling contribute to CD pathogenesis; (3) and to test in vivo and ex vivo in enteroids from mouse models of CD and CD patient samples, the therapeutic benefits of targeting these defects. Our study will advance scientific discovery and could lead to translation of the basic science to model novel therapies to advance CD patient care.

mRNA翻译的调节是细胞对任何形式的应激的最直接的反应之一。它是由 通过应激敏感激酶，所有这些激酶都磷酸化真核翻译起始因子的α亚基 2（EIF2A）。这导致了整体蛋白质合成的抑制，但伴随着选择性翻译， 对细胞存活和从压力中恢复至关重要的蛋白质。恢复细胞内稳态并逆转EIF 2A 在信号传导中，EIF 2A的去磷酸化由蛋白磷酸酶1（PP 1）与其一个磷酸化酶复合调节。 调节亚基和球状肌动蛋白（G-肌动蛋白）。因此，G-肌动蛋白限制了PP 1的活性，尽管细胞肌动蛋白 动力学被修改以调节PP 1活性是未知的。EIF 2A信号传导增加激活的翻译 转录因子4（ATF 4），以促进参与应激补救（如自噬）的基因表达 基因.相反，如果压力没有得到解决，ATF 4会调节促进细胞死亡的基因的转录 来清除受损细胞调节细胞在存活和存活之间的应激反应的控制开关 死亡控制着大多数炎性疾病的发生。与此一致，EIF 2A信号的慢性激活 与克罗恩病（CD）患者的粘膜炎症相关。尽管如此， EIF 2A信号在肠上皮细胞（IEC）中的作用尚不清楚。我们做了一个新奇的观察， IEC肌动蛋白细胞骨架履行作为细胞健康的生物传感器的一般功能并调节EIF 2A信号传导 以确定受到压力的细胞是存活还是死亡。我们表明，通过调节细胞肌动蛋白动力学，两个 同源肌动蛋白切断蛋白villin 1和凝溶胶蛋白整合应激信号通路与细胞命运 途径。使用villin 1/gelsolin双敲除小鼠，我们表明，当IEC之间的串扰 肌动蛋白细胞骨架和EIF 2A信号传导不能正常发挥作用，慢性炎症加剧。因此，在本发明中， DKO小鼠发生自发性回肠炎，在功能、组织学和临床上与人CD相似。 此外，我们对CD小鼠模型和CD患者样本的研究表明， IEC肌动蛋白细胞骨架和EIF 2A信号之间的联系可能是CD的普遍特征。我们建议 研究这些途径在IEC中的正常功能以及它们是如何出错的，可以为以下方面提供基本的见解： 这些事件驱动CD发病机制，但也可以确定CD的新治疗策略。我们提出了一个 创新的机械方法，使用最先进的技术，结合使用IEC系，转基因联合收割机， 以及经过验证的疾病小鼠模型和患者样本。本研究的目的是：（1）表征 肌动蛋白细胞骨架和应激信号之间的串扰决定的分子机制 IEC的命运;（2）以确定如何在肌动蛋白细胞骨架和应力信号之间的串扰的缺陷有助于 CD发病机制;（3）以及在来自CD小鼠模型和CD患者模型的类肠中进行体内和离体测试 样本，针对这些缺陷的治疗益处。我们的研究将推动科学发现， 可能会导致基础科学的翻译，以模拟新的疗法，以推进CD患者的护理。