Modulation of lysosomal pH by soluble Adenylyl Cyclase (sAC)

可溶性腺苷酸环化酶 (sAC) 调节溶酶体 pH 值

• 批准号: 8699524
• 负责人: Nawreen Rahman
• 金额: $ 4.27万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8699524
• 关键词: Ablation; Acids; Adenylate Cyclase; Aging; Alzheimer' s Disease; Apical; Autophagocytosis; Autophagosome; Bicarbonates; Brain region; Carbon Dioxide; Cathepsins; Cell model; Cells; Charge; Chloride Channels; Chloride Ion; Chlorides; Complex; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Defect; Disease; Embryo; Employee Strikes; Endocytosis; Environment; Eukaryota; Exhibits; Fibroblasts; Forskolin; Frontotemporal Dementia; Functional disorder; Future; GTP-Binding Proteins; Genetic; Goals; Hippocampus (Brain); In Vitro; Ion Transport; Ions; Laboratories; Lipids; Lumen of the Lysosome; Lysosomal Storage Diseases; Lysosomes; Mammalian Cell; Mediating; Membrane Potentials; Microglia; Mitotic; Molecular; Movement; Mus; Nerve Degeneration; Neurodegenerative Disorders; Neuronal Dysfunction; Neurons; Organelles; Parkinson Disease; Pathology; Pathway interactions; Peptide Hydrolases; Phenotype; Phosphorylation; Physiological; Polysaccharides; Process; Proteins; Proton Pump; Regulation; Second Messenger Systems; Signal Pathway; Signal Transduction; Signaling Molecule; Source; Surface; System; Testing; Time; Up-Regulation; Vesicle; Work; age related; age related neurodegeneration; in vivo; interest; neuron loss; novel; protein aggregate; public health relevance; research study; response; second messenger; sensor; trafficking; treatment strategy; vacuolar H+-ATPase

DESCRIPTION (provided by applicant): During age-related neurodegeneration, damaged proteins and organelles accumulate within neurons. These proteins and organelles are normally degraded in the lysosomes by cathepsins, which are optimally active at acidic pH. Elevation of lysosomal pH hinders normal degradation within lysosomes and impairs autophagy leading to neuronal dysfunction associated with aging, age-related diseases and lysosomal storage disorders. The molecular processes that regulate lysosomal pH are not clearly understood. In this application, I demonstrate that sAC, a pH-sensitive source of cAMP, is a modulator of lysosomal pH. Genetic or pharmacologic ablation of sAC elevates lysosomal pH leading to accumulation of proteins and autophagosomes both in vitro and in vivo. Thus, sAC is a pH-sensitive regulator of lysosomal pH, defining it as the only known lysosomal pH sensor. The goal of this proposal is to elucidate the mechanism by which sAC regulates lysosomal pH. I propose to test the hypothesis that sAC regulates lysosomal function by regulating trafficking and/or activity of V-ATPase and/or any of the channels and transporters (such as ClC-7) responsible for the counter ion current necessary for lysosomal acidification. I will pursue two Specific Aims: the first aim will elucidate the mechanism by which sAC regulates lysosomal pH in cellular systems. The second aim will investigate the molecular consequences of loss of sAC in vivo by examining whether sAC KO mice exhibit age related progression of lysosomal pathology. The experiments proposed in this application will better our understanding of the mechanism by which lysosomal pH is regulated, which in turn will enhance our understanding of aging, and age-related neurodegeneration and lysosomal storage disorders. If validated this hypothesis will lay the groundwork for future studies examining the particular neuronal deficits caused by sAC disruption, and may identify sAC as a potential target for novel treatment strategies for age-related and genetic neurodegenerative diseases.

描述（由申请人提供）：在与年龄相关的神经变性期间，神经元内积累的蛋白质和细胞器受损。这些蛋白质和细胞器通常通过组织蛋白酶在溶酶体中降解，在酸性pH值下具有最佳活性。溶酶体pH的升高阻碍溶酶体内的正常降解并损害自噬，导致与衰老，与年龄相关的疾病和溶酶体储存障碍有关的神经元功能障碍。调节溶酶体pH的分子过程尚不清楚。在此应用中，我证明了SAC是pH敏感的CAMP，是溶酶体pH的调节剂。 SAC的遗传或药理消融升高溶酶体pH，从而导致体外和体内蛋白质和自噬体的积累。因此，SAC是溶酶体pH的pH敏感调节剂，将其定义为唯一已知的溶酶体pH传感器。该提案的目的是阐明SAC调节溶酶体pH的机制。我建议测试通过调节V-ATPase和/或任何通道和转运蛋白（例如CLC-7）的运输和/或活性来调节溶酶体功能的假设，该假设负责溶酶体酸化所需的反离子电流。我将追求两个具体的目标：第一个目标将阐明SAC调节细胞系统中溶酶体pH的机制。第二个目的将通过检查SAC KO小鼠是否表现出与年龄相关的溶酶体病理学进展，研究体内囊丢失的分子后果。本应用程序中提出的实验将更好地理解调节溶酶体pH的机制，从而增强我们对衰老以及与年龄相关的神经变性和溶酶体储存障碍的理解。如果得到验证，该假设将为未来研究的基础研究，以研究由SAC中断引起的特定神经元缺陷，并可能将SAC鉴定为针对年龄相关和遗传神经退行性疾病的新型治疗策略的潜在目标。

项目成果

pH sensing via bicarbonate-regulated "soluble" adenylyl cyclase (sAC).

• DOI: 10.3389/fphys.2013.00343
• 发表时间: 2013-11-25
• 期刊: Frontiers in physiology
• 影响因子: 4
• 作者: Rahman N;Buck J;Levin LR
• 通讯作者: Levin LR