Lysosomal Enzymes in Outflow Pathway Physiology and Pathophysiology

流出途径生理学和病理生理学中的溶酶体酶

基本信息

批准号：
9284304
负责人：
Paloma Liton
金额：
$ 45.75万
依托单位：
DUKE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-06-01 至 2021-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9284304
关键词：
Aging Agreement Alpha Cell Applications Grants Aqueous Humor Biochemical Blindness Caspase Cathepsins Cathepsins B Caveolae Cell Surface Receptors Cell surface Cells Clinical Clinical Trials Collagen Collagen Fiber Connective Tissue Cues Data Degradation Pathway Deposition Disease Drainage procedure Drug Targeting Elastic Fiber Endothelial Cells Environment Enzymes Etiology Extracellular Matrix Eye Functional disorder Future Glaucoma Ground Substance Human Image In Vitro Laboratories Matrix Metalloproteinases Mechanics Mediating Modeling Molecular Mus Nature Ocular Hypertension Pathogenesis Pathway interactions Patients Peptide Hydrolases Pharmacology Physiologic Intraocular Pressure Physiology Play Primary Open Angle Glaucoma Proteomics Resistance Retinal Ganglion Cells Risk Role Route Serine Protease Testing Time Tissues Trabecular meshwork structure Transforming Growth Factor Beta 2 Transforming Growth Factor beta Work base carboxypeptidase C extracellular in vivo novel novel therapeutics prevent protein B uptake

项目摘要

SUMMARY Defective aqueous humor (AH) drainage through the trabecular meshwork (TM) / Schlemm's cannal (SC) conventional outflow pathway is usually associated to elevated intraocular pressure (IOP), and hence, increased risk for developing glaucoma, a blinding disease second leading cause of permanent blindness in the US. The nature of such resistance to AH outflow is far from being elucidated. The TM consists of sheets of connective tissue beams lined by TM endothelial cells. Each beam is composed of a central elastic core surrounded by collagen fibers embedded in a ground substance. The glaucomatous outflow pathway is characterized by thickening of the trabecular lamellae and accumulation of long-spacing collagen bundles and elastic fiber sheaths, which is presumed to stiffen the TM and prevent the tissue to respond to mechanical cues. The exact causes underlying the deposit of extracellular material (ECM) and thickening of the beams remain unknown; but it is likely a consequence of excessive synthesis of ECM components, decreased proteolytic degradation, or both. Matrix metalloproteinases (MMPs) have been historically believed to be the major proteases involved in ECM degradation; however, emerging evidence indicates that while MMPs play a critical role in initiating ECM degradation in the extracellular environment, other proteases or the coordinated action of several types of proteases (i.e. cysteine and serine proteases) are responsible for the bulk matrix degradation, occurring pericellularly and intracellularly in the lysosomal compartment, associated to lysosomal cathepsins. In agreement, studies conducted in our laboratory have clearly demonstrated the constitutive cell surface expression and secretion of cathepsin B (CTSB) in TM cells and its participation in the endocytic uptake and intralysosomal degradation of native and denature collagens. Here we propose to investigate for the first time the contribution of a CTSB-mediated pericellular and intracellular ECM degradative pathway in TM cells and the effect on outflow physiology. We hypothesize that CTSB plays a critical role in ECM remodeling and outflow physiology by initiating a proteolytic cascade leading to the pericellular and intracellular degradation of ECM components in TM cells. We further hypothesize that modulation of CTSB activity may represent a novel therapeutic strategy in glaucoma. To test this hypothesis, we will (1) demonstrate that CTSB associates with caveolae and initiates a proteolytic cascade resulting in the partial degradation of ECM components; (2) determine the cell surface receptors participating in of ECM components in TM cells; and (3) evaluate the effects of modulating CTSB activity in outflow pathway function of murine glaucoma models.

概括通过小梁网 (TM)/施累姆氏管 (SC) 的房水 (AH) 引流缺陷传统的流出途径通常与眼内压（IOP）升高有关，因此，患青光眼的风险增加，青光眼是一种致盲性疾病，导致永久失明的第二大原因美国。这种对 AH 流出的抵制的本质还远未得到阐明。 TM 由排列有 TM 内皮细胞的结缔组织束片组成。每根梁由中央弹性核心被嵌入基质中的胶原纤维包围。青光眼者流出通路的特点是小梁板层增厚和长间距积累胶原束和弹性纤维鞘，据推测可以使 TM 变硬并防止组织变形对机械提示做出反应。细胞外物质（ECM）沉积的确切原因和梁的加厚情况仍然未知；但这很可能是ECM过度合成的结果成分，减少蛋白水解降解，或两者兼而有之。基质金属蛋白酶（MMP）已被历史上认为是参与 ECM 降解的主要蛋白酶；然而，新出现的证据表明虽然 MMP 在细胞外环境中启动 ECM 降解中发挥着关键作用，其他蛋白酶或几种蛋白酶（即半胱氨酸和丝氨酸蛋白酶）的协调作用负责溶酶体中细胞周围和细胞内发生的大量基质降解室，与溶酶体组织蛋白酶相关。一致认为，我们实验室进行的研究清楚地证明了 TM 细胞中组织蛋白酶 B (CTSB) 的组成型细胞表面表达和分泌及其参与天然和变性胶原蛋白的内吞摄取和溶酶体内降解。在这里，我们建议首次研究 CTSB 介导的细胞周和细胞的贡献。 TM细胞内ECM降解途径及其对流出生理学的影响。我们假设 CTSB 通过启动蛋白水解在 ECM 重塑和流出生理学中发挥关键作用级联反应导致 TM 细胞中 ECM 成分的细胞周和细胞内降解。我们进一步假设 CTSB 活性的调节可能代表一种新的治疗策略青光眼。为了检验这一假设，我们将 (1) 证明 CTSB 与小窝相关并启动蛋白水解级联导致 ECM 成分部分降解； (2)测定细胞表面参与TM细胞ECM成分的受体； (3) 评估调节 CTSB 的效果小鼠青光眼模型流出途径功能的活性。