Direct Regulation of Extracellular Proteostasis by the Unfolded Protein Response

通过未折叠的蛋白质反应直接调节细胞外蛋白质稳态

基本信息

批准号：
9065690
负责人：
Rockland Luke Wiseman
金额：
$ 42.02万
依托单位：
SCRIPPS RESEARCH INSTITUTE, THE
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-07-01 至 2020-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9065690
关键词：
Address Alzheimer&apos s Disease Amyloidosis Attenuated Binding Biochemical Biological Biological Assay Caenorhabditis elegans Cell Culture Techniques Cells Complex Creutzfeldt-Jakob Syndrome DNA Sequence Alteration Degenerative Disorder Deposition Disease Endoplasmic Reticulum Environment Extracellular Protein Extracellular Space Genetic Goals Health Homeostasis Individual Link Mammalian Cell Mediating Mitotic Modeling Molecular Molecular Chaperones Neurons Outcome Pathogenesis Pathologic Pathology Pathway interactions Phenotype Prealbumin Predisposing Factor Prions Protein Conformation Proteins Regulation Signal Pathway Signal Transduction Stress Structure Therapeutic Tissues Variant age related biological adaptation to stress endoplasmic reticulum stress extracellular interest meetings normal aging novel therapeutics prevent protein aggregation response small molecule sulfated glycoprotein 2 transcription factor

项目摘要

DESCRIPTION (provided by applicant): The misfolding and extracellular aggregation of destabilized, amyloidogenic proteins is inextricably linked to degenerative phenotypes in over 30 protein aggregation (i.e., amyloid) diseases including Alzheimer's disease, Creutzfeldt-Jakob disease and the systemic amyloidoses. Significant pharmacologic and genetic evidence confirms a causal relationship between protein aggregation and degeneration of post-mitotic tissues in these diseases. The importance of extracellular protein aggregation in amyloid disease pathology has stimulated significant experimental effort focused on defining the organismal and cellular pathways that regulate protein homeostasis (or proteostasis) in the extracellular environment. One such pathway is the Unfolded Protein Response (UPR) - the stress-responsive signaling pathways responsible for regulating proteostasis within the secretory pathway in response to endoplasmic reticulum (ER) stress. Previous results from our lab and others have shown that the UPR indirectly influences extracellular aggregation of destabilized, amyloidogenic proteins by reducing their secretion from mammalian cells, thus decreasing extracellular protein levels available for concentration-dependent aggregation. Here, we hypothesize that UPR activation also directly regulates extracellular proteostasis through the increased expression and secretion of extracellular chaperones that prevent the proteotoxic aggregation of destabilized, aggregation-prone proteins. We have identified the ER-targeted HSP40 co-chaperone ERdj3 as a UPR regulated, secreted chaperone that promotes extracellular proteostasis in response to ER stress. We show that ERdj3 attenuates the aggregation and proteotoxicity of disease-associated, aggregation-prone secreted proteins including Aß40 and toxic prion protein (TPrP). Additionally, we show that ERdj3 is co-secreted in a complex with destabilized, aggregation-prone proteins under conditions where ER proteostasis pathways are overwhelmed, providing a mechanism to preemptively protect the extracellular environment from proteotoxic extracellular protein aggregation. In this application, we expand on these findings using biophysical, biochemical and cell biological approaches to define the molecular mechanisms by which UPR-dependent ERdj3 secretion protects the extracellular environment against proteotoxic protein conformations. Through these efforts, we will identify specific aspects of UPR-regulated ERdj3 secretion directly involved in preventing the proteotoxic aggregation of destabilized secreted proteins associated with amyloid disease pathology. These results will demonstrate that altered UPR signaling, such as those that occur during normal aging or in response to amyloid-disease associated genetic mutations, can facilitate aging-dependent extracellular protein aggregation involved in amyloid disease pathogenesis. Furthermore, we will identify components of UPR signaling pathways that can be therapeutically targeted to promote extracellular proteostasis and prevent extracellular protein aggregation, revealing a new strategy to attenuate proteotoxicity of secreted proteins involved in the pathology of amyloid diseases.

描述（由申请人提供）：不稳定的淀粉样蛋白的错误折叠和细胞外聚集与 30 多种蛋白质聚集（即淀粉样蛋白）疾病的退化表型有着千丝万缕的联系，包括阿尔茨海默病、克雅氏病和系统性淀粉样变性。遗传证据证实了蛋白质聚集和退化之间的因果关系有丝分裂后组织在淀粉样蛋白疾病病理学中的重要性激发了重大的实验工作，重点是确定调节细胞外环境中蛋白质稳态（或蛋白质稳态）的有机体和细胞途径。蛋白质反应 (UPR) - 应激反应信号通路，负责调节分泌通路内的蛋白质稳态，以响应内质网 (ER) 应激。实验室和其他人已经表明，UPR 通过减少哺乳动物细胞的分泌来间接影响不稳定的淀粉样蛋白的细胞外聚集，从而降低可用于浓度依赖性聚集的细胞外蛋白质水平在这里，我们帮助 UPR 激活还通过直接调节细胞外蛋白质稳态。细胞外伴侣的表达和分泌增加，可防止不稳定的、易于聚集的蛋白质发生蛋白毒性聚集。 ER 靶向 HSP40 共伴侣 ERdj3 作为 UPR 调节的分泌伴侣，可促进细胞外蛋白质稳态以应对 ER 应激(TPrP) 此外，我们表明 ERdj3 是共同分泌的。在内质网蛋白质稳态途径被压倒的条件下，与不稳定的、易于聚集的蛋白质形成复合物，提供了一种先发制人地保护细胞外环境免受蛋白质毒性细胞外蛋白质聚集的机制。在本应用中，我们利用生物物理、生物化学和细胞生物学扩展了这些发现。方法来定义 UPR 依赖性 ERdj3 分泌保护细胞外环境免受蛋白毒性蛋白构象影响的分子机制。通过这些努力，我们将确定其具体方面。 UPR 调节的 ERdj3 分泌直接参与防止与淀粉样蛋白疾病病理学相关的不稳定分泌蛋白的蛋白毒性聚集，这些结果将证明改变的 UPR 信号传导，例如在正常衰老过程中或响应淀粉样蛋白疾病相关基因突变时发生的信号传导，可以促进参与淀粉样蛋白疾病发病机制的衰老依赖性细胞外蛋白聚集。此外，我们将鉴定可作为治疗靶点促进细胞外蛋白聚集的 UPR 信号通路成分。蛋白质稳态并防止细胞外蛋白质聚集，揭示了一种减轻淀粉样蛋白疾病病理学中分泌蛋白的蛋白质毒性的新策略。