Unfolded Protein Response in Lens Epithelial Cells

晶状体上皮细胞中未折叠的蛋白质反应

• 批准号: 7881521
• 负责人: TOSHIMICHI SHINOHARA
• 金额: $ 32.74万
• 依托单位: UNIVERSITY OF NEBRASKA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7881521
• 关键词: Address; Apoptosis; Binding; Biological Assay; Caspase; Cataract; Cell Death; Cell Survival; Cells; Cellular Stress; Cessation of life; Chemicals; Chronic; Crystallins; Development; Diabetes Mellitus; Disease; Disulfides; Endoplasmic Reticulum; Enzymes; Epithelial; Epithelial Cells; Event; Exhibits; Eye; Family; Free Radicals; Galactosemias; Genes; Genetic Transcription; Glutathione; Growth Factor; Human; Laboratories; Lipoxygenase; Microarray Analysis; Mitochondria; Mitotic; Molecular Chaperones; Pathway interactions; Patients; Pharmaceutical Preparations; Production; Protein Conformation; Protein Disulfide Isomerase; Proteins; Rattus; Reaction; Reactive Oxygen Species; Reporting; Research; Respiratory Chain; Retinal Diseases; Role; Source; Staging; Stress; Study Subject; Testing; Time; Transcription Coactivator; Ubiquitin; Up-Regulation; cell type; chromatin immunoprecipitation; design; diabetic; diabetic cataract; diabetic rat; endoplasmic reticulum stress; killings; lens; nanoparticle; novel; novel therapeutic intervention; oxidation; poly(lactide); promoter; prophylactic; protein aggregation; protein folding; public health relevance; research study; response; stressor; tauroursodeoxycholic acid; text searching; trimethyloxamine

DESCRIPTION (provided by applicant): Activation of a stress pathway is a primary cause of many types of cataracts. A search of the literatures has indicated that misfolded protein conformations in the endoplasmic reticulum (ER) induce ER stress, and prolonged ER stress oxidizes and kills numerous cell types. Our laboratory has previously proposed that many cataractogenic stressors also exhibit endoplasmic reticulum (ER) stress and induce well-defined protective and death pathways called the unfolded protein response (UPR). The first stage of the UPR protects cells against stress, and cells eliminate the unfolded modified proteins from the ER by the ubiquitin dependent ER-associated degradation (ERAD). However, prolonged ER stress activates the second stage of the UPR, which leads to activation of the UPR dependent death pathway. The UPR death pathway activates specific proteins including caspases, stimulates Ca++ release and the over production of reactive oxygen species (ROS), and results in LEC death. Lens epithelial cell derived growth factor (LEDGF) is known to be a transcriptional activator and survival factor and rescues various cell types under stress conditions by up-regulating expression of the stress associated genes. A recent study has suggested that prolonged ER stress activates the expression of the ledgf gene. Thus, we propose that the UPR also activates an eclectic survival pathway, which activates the ledgf gene and downstream survival genes to promote cell survival under prolonged ER stress. Chemical chaperones (PBA and TMAO) and TUDCA are reported to suppress ER stress. Recently we showed that these drugs reduced ER stress, delayed LEC death, and alleviated cataract formation. These results opened novel opportunities of research to develop prophylactic drugs for LEC and cataract development. Aim 1 is to test that A) diabetes induces the UPR, which produces ROS, induces LEC death, and promotes cataract formation in rats, B) the UPR induces abnormal LEC proliferation in galactosemic rat LECs, and C) these proliferative LECs are preferentially attacked by ER stress. We believe that these above events are involved in cataract development. Aim 2 is to test whether LEDGF is a prosurvival downstream activator in the UPR and if the UPR pathway regulates the transcription of the ledgf gene in galactosemic LECs. Stimulation of the LEDGF protective pathway could be another way of alleviating cataract in chronic diabetes. Aim 3 is to test whether chemical chaperones and TUDCA can be used as prophylactic agents to suppress the death of LECs in galactosemic and diabetic cataract. The drugs will be trapped in poly-lactide-co-glycolides (PLGA) nanoparticles and directly inject into the vitreal space. The PLGA can deliver larger amounts of drugs and slowly release these drugs over a long time. PUBLIC HEALTH RELEVANCE: Activation of stress pathway is a primary cause of many types of diseases including cataracts. One form of stress, so called endoplasmic reticulum (ER) stress, is caused by misfolded protein conformation. The ER stress produces reactive oxygen species (ROS) to oxidize free glutathione and proteins and induces cell death in the lens. We will study the roles of the UPR in lens epithelial cell death and cataract fromation in diabetic and galactosemic rats. Furthermore, lens epithelial derived growth factor (LEDGF) is elevated in cells under ER stress, we will study the basic notion of up-regulation of LEDGF in the UPR pathway, which may open an alternative survival pathway. Finally, chemical chaperones and TUDCA are known to reduce ER stress dependent cell death. We will study whether these chaperones and TUDCA can be used as prophylactic drugs to suppress ER stress, ROS production, LEC death, and cataract development. Modulating ER stress by these chaperones and TUDCA may offer a novel therapeutic approach to the treatment of human patients with cataract.

描述（由申请人提供）：应力途径的激活是多种类型白内障的主要原因。对文献的搜索表明，内质网中（ER）中错误折叠的蛋白质构象会诱导ER应激，并延长ER应力氧化并杀死许多细胞类型。我们的实验室先前提出，许多白内生应激源也表现出内质网应激（ER）应力，并诱导明确的保护性和称为已展开的蛋白质反应（UPR）的死亡途径。 UPR的第一阶段可保护细胞免受胁迫的影响，细胞通过依赖蛋白依赖的ER相关降解（ERAD）消除了未折叠的改性蛋白从ER中。然而，延长的ER应力激活了UPR的第二阶段，这导致了UPR依赖性死亡途径的激活。 UPR死亡途径激活包括胱天蛋白酶在内的特定蛋白质，刺激Ca ++的释放和活性氧（ROS）的过度产生，并导致LEC死亡。晶状体上皮细胞得出的生长因子（LEDGF）是转录激活因子和生存因子，并通过上调应力相关基因的表达在应力条件下营救了各种细胞类型。最近的一项研究表明，延长的ER应力激活了LEDGF基因的表达。因此，我们建议UPR还激活了折衷的生存途径，该途径激活了LEDGF基因和下游生存基因，以在长期的ER应激下促进细胞存活。据报道，化学伴侣（PBA和TMAO）和TUDCA抑制ER应激。最近，我们表明这些药物减轻了ER应力，LEC死亡延迟并减轻了白内障的形成。这些结果为开发用于LEC和白内障发育的预防性药物开辟了新的研究机会。目的1是测试a）糖尿病会诱导产生ROS，诱导LEC死亡的UPR，并促进大鼠的白内障形成，b）UPR诱导肠道症状大鼠LEC中的异常LEC增殖，以及C）这些增殖性LEC受到ER应力而受到ER应力的攻击。我们认为，这些上述事件参与白内障发展。 AIM 2是测试LEDGF是否是UPR中的Prosurvival下游激活因子，以及UPR途径是否调节了半乳症LEC中LEDGF基因的转录。刺激LEDGF保护途径可能是减轻慢性糖尿病白内障的另一种方法。 AIM 3是测试化学伴侣和TUDCA是否可以用作预防剂，以抑制银河系和糖尿病性白内障中LEC的死亡。这些药物将被困在聚乳酸 - 糖苷（PLGA）纳米颗粒中，并直接注入玻璃体空间。 PLGA可以很长时间以来提供大量药物，并慢慢释放这些药物。公共卫生相关性：压力途径的激活是包括白内障在内的许多类型疾病的主要原因。一种形式的压力，即所谓的内质网（ER）应激，是由错误折叠的蛋白质构象引起的。 ER应激会产生活性氧（ROS）以氧化游离谷胱甘肽和蛋白质，并诱导透镜中的细胞死亡。我们将研究UPR在晶状体上皮细胞死亡和糖尿病和半乳术大鼠中的作用。此外，在ER应力下，细胞中透镜上皮衍生因子（LEDGF）升高，我们将研究UPR途径中LEDGF上调的基本概念，这可能打开另一种生存途径。最后，已知化学伴侣和TUDCA可以减少依赖于ER应力的细胞死亡。我们将研究这些伴侣和TUDCA是否可以用作预防药物来抑制ER应激，ROS产生，LEC死亡和白内障发育。调节这些伴侣和TUDCA的ER应激可能为治疗人性白内障患者的治疗提供一种新型的治疗方法。