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: 9789258
• 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/9789258
• 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; Intestines; 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 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最直接的反应之一。 通过应激感应激酶，所有这些激酶都会磷酸化真核翻译起始因子的α亚基 2 (EIF2A) 这会导致整体蛋白质合成的抑制，但伴随着选择性翻译。 对细胞生存和应激恢复至关重要的蛋白质 恢复细胞稳态并逆转 EIF2A。 EIF2A 的去磷酸化受蛋白磷酸酶 1 (PP1) 及其一种复合物的调节 因此，调节亚基和球状肌动蛋白 (G-肌动蛋白) 限制了 PP1 的活性，尽管细胞肌动蛋白的活性如何。 改变动力学以调节 PP1 活性尚不清楚。 转录因子 4 (ATF4) 促进参与应激修复（例如自噬）的基因表达 如果压力未解决，基因就会离线 ATF4 调节促进细胞死亡的基因的转录。 消除受损细胞的控制开关，调节细胞生存和应激反应。 死亡控制着大多数炎症性疾病的发生，与此一致的是，EIF2A 信号传导的慢性激活。 尽管如此，分子基础却与克罗恩病（CD）患者的粘膜炎症有关。 肠上皮细胞 (IEC) 中 EIF2A 信号传导的机制仍不清楚。 IEC 肌动蛋白细胞骨架履行细胞健康生物传感器的一般功能并调节 EIF2A 信号传导 为了确定受应激的细胞是否会生存或死亡，我们证明，通过调节细胞肌动蛋白动力学，可以实现两个目标。 同源肌动蛋白切断蛋白villin1和凝溶胶蛋白将应激信号通路与细胞命运整合 使用villin1/gelsolin双敲除小鼠，我们发现当IEC之间存在串扰时 肌动蛋白细胞骨架和 EIF2A 信号传导无法正常发挥作用，从而导致慢性炎症。 DKO 小鼠会出现自发性回肠炎，其功能、组织学和临床类似于人类 CD。 此外，我们对 CD 小鼠模型和 CD 患者样本的研究表明，串扰缺陷 IEC 肌动蛋白细胞骨架和 EIF2A 信号之间的相互作用可能是 CD 的普遍特征。 研究这些通路在 IEC 中如何正常运作以及它们如何出错可以提供基本的见解 我们提出了一种驱动 CD 发病机制的事件，但也可以确定新的 CD 治疗策略。 采用最先进技术的创新机械方法，结合了 IEC 线、转基因技术的使用 以及经过验证的疾病小鼠模型和患者样本。该研究的目标是：（1）表征。 肌动蛋白细胞骨架和应激信号传导之间的串扰决定的分子机制 IEC 命运；(2) 确定肌动蛋白细胞骨架和应激信号传导之间的串扰缺陷如何发挥作用 CD 发病机制；(3) 并在 CD 和 CD 患者的小鼠模型中进行体内和离体测试 样本，针对这些缺陷的治疗益处将推动科学发现和发展。 可能会导致基础科学转化为新疗法模型，以促进 CD 患者护理。