Evaluation of Prg4 as a New Therapy for TMJ Disc Degeneration

Prg4 作为 TMJ 椎间盘退变新疗法的评估

基本信息

批准号：
10525000
负责人：
EIKI KOYAMA
金额：
$ 23.63万
依托单位：
CHILDREN'S HOSP OF PHILADELPHIA
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-08-05 至 2024-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10525000
关键词：
Address Age-Months Architecture Biological Models Biology Biomechanics Cartilage Cell Death Cell Differentiation process Cell Maturation Cell physiology Cells Chondrocytes Data Development Diagnosis Diphtheria Toxin Disease Enterobacteria phage P1 Cre recombinase Evaluation Excision Exhibits Expression Profiling Extracellular Matrix Female Friction Gene Expression Genes Glenoid structure Glycoproteins Goals Grant Growth Histopathology Homeostasis Human Hyaluronic Acid Impairment Incidence Joints Knee Knock-out Knowledge Lead Lubricants Lubrication Maintenance Mandibular Condyle Mastication Mechanics Mediating Medical Monitor Morphogenesis Multiple Anatomic Sites Mus Orofacial Pain Pathologic Patients Persons Phenotype Phospholipids Physiology Play Population Proteoglycan Quality of life Reflex action Rest Rodent Role Sampling Shapes Signal Pathway Signaling Molecule Site Slide Speech Structure Structure of articular disc of temporomandibular joint Structure-Activity Relationship Synovial Fluid Synovial joint System TMJ disk displacement TNFSF5 gene Tamoxifen Temporal bone structure Temporomandibular Joint Temporomandibular Joint Disorders Temporomandibular Joint Dysfunction Syndrome Temporomandibular joint osteoarthritis Testing Therapeutic Therapeutic Intervention Time Tissues United States Viral behavior test biomechanical test calcification condylar cartilage effective therapy experimental study in vivo intervertebral disk degeneration joint destruction joint function joint mobilization laser capture microdissection lubricin male mechanical load mechanical properties mineralization mouse model novel novel therapeutics overexpression postnatal prevent protein expression restoration substantia spongiosa successful intervention therapeutic evaluation therapeutic target trait transcriptome sequencing translational approach translational medicine

项目摘要

The temporo-mandibular joint (TMJ), composed of the mandibular condyle, the glenoid fossa of the temporal bone and the articular disc, is essential for speech and mastication. The disc plays an important role in TMJ movement, by allowing the condyle to freely slide down the slope of the glenoid fossa. TMJ disorders (disruption in the structure, function or physiology of the TMJ) afflict approximately 20% of the U.S. population, and up to 70% of the conditions are due to TMJ disc displacement and/or damage. It is generally believed that aberrations in the lubrication system, which depends primarily on joint lubricants, including hyaluronic acid, phospholipid, and Proteoglycan 4 (Prg4), contribute to TMJ dysfunction. A critical gap in knowledge is to clarify the extent to which joint lubricants establish and maintain the structure and function of the TMJ disc. We found that TMJs of Prg4-null (Prg4-/-) mice exhibited significantly greater degenerative changes compared to other synovial joints, including the knee. We found in Prg4-/- mice that: (a) the TMJ discs failed to develop their biconcave shape and became substantially thickened over time; (b) a large number of the disc cells differentiated into fibrochondrocytes, leading to disc mineralization; and (c) subsequently, the condylar cartilage broke down and the trabecular bone exhibited architectural changes. In addition, the mechanical properties of the Prg4-/- discs were significantly altered compared to controls. These and other novel data lead to our central hypothesis that Prg4 is necessary: 1) to maintain TMJ disc cell phenotype and function, and 2) to protect the TMJ from degenerative changes. In Aim 1, we will determine the signaling pathways, by which PRG4 regulates region- and stage-specific phenotypes of disc cells across multiple anatomical sites, and elucidate how global loss of Prg4 leads to abnormal disc cell function and disc zonal organization. By inducing cell death in Prg-4 expressing cells postnatally, we will also define the roles of Prg4- expressing cells in disc morphogenesis and homeostasis. In Aim 2, we will test if TMJ disc degeneration is treatable, and, if so, also determine if there is a therapeutic window for successful intervention. We will restore Prg4 expression postnatally via virally-driven overexpression of Prg4 and tamoxifen or virally-driven Cre recombinase in ROSA26CreERT2;Prg4GT (Prg4cGT) mice, which have a reversible gene-trap (GT) in Prg4 (Prg4GT), in which Prg4 expression is activated upon Cre-mediated excision of the gene-trap. Phenotypic analyses will include histopathology, gene and protein expression, and biomechanical tests. Orofacial pain will be evaluated by mechanical reflex testing and rodent grimace scale. Our project will provide novel and far- reaching information regarding the role of joint lubricants in TMJ disc maintenance and disease. Our rescue experiments should provide a proof-of-principle that TMJ disc degeneration is amenable to therapeutic intervention. While our experiments use the TMJ as a model system, we believe results from this application will also be directly applicable to other synovial joints.

颞下颌关节（TMJ），由下颌髁突、关节窝组成颞骨和关节盘，对于言语和咀嚼至关重要。光盘发挥着重要作用在 TMJ 运动中，通过允许髁突沿着关节窝的斜坡自由滑动。颞下颌关节紊乱（颞下颌关节结构、功能或生理学的破坏）困扰着大约 20% 的美国人人群中，高达 70% 的病症是由于颞下颌关节盘移位和/或损伤造成的。一般是认为润滑系统中的畸变主要取决于关节润滑剂，包括透明质酸、磷脂和蛋白聚糖 4 (Prg4) 会导致 TMJ 功能障碍。关键差距知识的目的是阐明关节润滑剂在多大程度上建立和维持关节的结构和功能颞下颌关节盘。我们发现 Prg4-null (Prg4-/-) 小鼠的 TMJ 表现出明显更大的退行性与其他滑膜关节（包括膝关节）相比发生了变化。我们在 Prg4-/- 小鼠中发现： (a) TMJ 随着时间的推移，椎间盘未能形成双凹形状，并且变得明显增厚； (b) 大量椎间盘细胞分化为纤维软骨细胞，导致椎间盘矿化； (c) 随后，髁软骨破裂，骨小梁出现结构变化。此外，与对照相比，Prg4-/- 圆盘的机械性能显着改变。这些和其他新数据引出了我们的中心假设，即 Prg4 是必要的：1) 维持 TMJ 盘细胞表型和功能，以及 2) 保护 TMJ 免受退行性变化。在目标 1 中，我们将确定信号 PRG4 通过这些途径调节多个椎间盘细胞的区域和阶段特异性表型解剖部位，并阐明 Prg4 的整体缺失如何导致椎间盘细胞功能和椎间盘区域异常组织。通过在出生后诱导 Prg-4 表达细胞的细胞死亡，我们还将定义 Prg4-的作用椎间盘形态发生和稳态中的表达细胞。在目标 2 中，我们将测试 TMJ 椎间盘退变是否可以治疗，如果可以，还可以确定是否存在成功干预的治疗窗口。我们将恢复 Prg4 出生后通过病毒驱动的 Prg4 和他莫昔芬或病毒驱动的 Cre 过表达进行表达 ROSA26CreERT2;Prg4GT (Prg4cGT) 小鼠中的重组酶，其在 Prg4 中具有可逆基因陷阱 (GT) (Prg4GT)，其中 Prg4 表达在 Cre 介导的基因陷阱切除后被激活。表型分析将包括组织病理学、基因和蛋白质表达以及生物力学测试。口面部疼痛会通过机械反射测试和啮齿动物鬼脸量表进行评估。我们的项目将提供新颖且深远的获取有关关节润滑剂在 TMJ 椎间盘维护和疾病中的作用的信息。我们的救援实验应提供原理证明，证明 TMJ 椎间盘退变适合治疗干涉。虽然我们的实验使用 TMJ 作为模型系统，但我们相信该应用程序的结果也将直接适用于其他滑膜关节。