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

• 批准号: 10677033
• 负责人: EIKI KOYAMA
• 金额: $ 26.96万
• 依托单位: CHILDREN'S HOSP OF PHILADELPHIA
• 依托单位国家: 美国
• 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/10677033
• 关键词: Ablation; Address; Age Months; Architecture; Biological Models; Biology; Biomechanics; Cartilage; Cell Death Induction; 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; Knockout Mice; 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; Predisposition; Proteoglycan; Qualifying; 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; 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; comparison control; 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

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.

由下颌骨con组成的颞下颌关节（TMJ）， 颞骨和关节盘对于言语和咀嚼至关重要。唱片起着重要的作用 在TMJ运动中，通过允许con脚自由滑动垂体窝的斜率。 TMJ疾病 （TMJ的结构，功能或生理学破坏）折磨于美国约20％ 人口，最多70％的条件是由于TMJ光盘位移和/或损坏引起的。通常是 认为润滑系统中的畸变主要取决于联合润滑剂，包括 透明质酸，磷脂和蛋白聚糖4（PRG4）导致TMJ功能障碍。一个关键的差距 知识是要阐明关节润滑剂建立和维护的结构和功能的程度 TMJ光盘。我们发现PRG4-NULL（PRG4 - / - ）小鼠的TMJ表现出明显更大的退化性 与其他滑膜（包括膝盖）相比，变化。我们在PRG4 - / - 鼠标中发现：（a）TMJ 圆盘未能发展出双孔形状，并且随着时间的流逝而变得大大变厚。 （b）大量 椎间盘细胞分化为纤维软骨细胞，导致盘矿化； （c）随后， Condylar软骨破裂，小梁骨出现建筑变化。另外， 与对照组相比，PRG4 - / - 光盘的机械性能显着改变。这些和其他 新的数据导致我们的核心假设，即PRG4是必要的：1）维持TMJ盘细胞表型和 功能和2）保护TMJ免受退化性变化。在AIM 1中，我们将确定信号传导 途径，PRG4调节多个圆盘细胞的区域和阶段特异性表型 解剖部位，并阐明PRG4的全局损失如何导致异常椎间盘功能和圆盘层次 组织。通过出生后PRG-4表达细胞中的细胞死亡，我们还将定义PRG4-的作用 在椎间盘形态发生和稳态中表达细胞。在AIM 2中，我们将测试TMJ圆盘变性是否为 可以治疗，如果是这样，还可以确定是否有成功干预的治疗窗口。我们将还原 PRG4通过病毒驱动的PRG4和他莫昔芬或病毒驱动的CRE的pRG4表达 rosa26creert2; pRG4GT（PRG4CGT）小鼠中的重组酶，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术时被激活。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。口面疼痛会 可以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而遥远的 获取有关联合润滑剂在TMJ椎间盘维持和疾病中的作用的信息。我们的营救 实验应提供原则上的证明，表明TMJ椎间盘变性适合治疗 干涉。当我们的实验使用TMJ作为模型系统时，我们相信此应用程序的结果 也将直接适用于其他滑膜。