Mechanism of Tgfbr2 in chondroprotection

Tgfbr2的软骨保护机制

• 批准号: 8497046
• 负责人: Rosa A. Serra
• 金额: $ 31.18万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-01 至 2018-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8497046
• 关键词: Adenoviruses; Affect; Animal Model; Arginine; Arthralgia; Arthritis; Binding Sites; Biochemical; Biological; Biomechanics; Bioreactors; Bovine Cartilage; Boxing; Cartilage; Cattle; Centers for Disease Control and Prevention (U.S.); Chondrocytes; Data; Degenerative polyarthritis; Deposition; Development; Dominant-Negative Mutation; Dysplasia; Engineering; Enzymes; Extracellular Matrix; Extracellular Matrix Proteins; Genes; Human; Inorganic Sulfates; Introns; Investigation; Joints; Knowledge; Laboratories; Lead; Lysine; Maintenance; Mediating; Messenger RNA; Modeling; Mus; Peptides; Phenotype; Plasmids; Prevention strategy; Process; Property; Proteins; Proteoglycan; RNA Interference; Regulation; Role; Signal Transduction; Site; Staining method; Stains; Stream; Testing; Tissue-Specific Gene Expression; Tissues; Transcriptional Activation; Transforming Growth Factor beta; Transgenic Mice; Unspecified or Sulfate Ion Sulfates; Virus; articular cartilage; cartilage regeneration; disability; expression vector; genetic manipulation; in vivo; joint function; mouse model; mutant; new therapeutic target; prevent; promoter; public health relevance; receptor; repaired; response; sex; skeletal disorder; sulfation; transcription factor; treatment strategy

DESCRIPTION (provided by applicant): Osteoarthritis is a leading cause of disability in the industrialized world but little is known about mechanisms of cartilage destruction associated with osteoarthritis. Recent advances in the genetic manipulation of mice have lead to new animal models and new concepts that are relevant to understanding osteoarthritis in humans. The long-term objective of my laboratory is to understand the factors that mediate the development, persistence, and repair of articular cartilage and to identify specific targets for prevention and treatment strategies for osteoarthritis. TGF-¿ is a multifunctional peptide that has been shown to regulate cellular differentiation and tissue-specific gene expression. Previously, we generated transgenic mice that express a dominant-negative mutation of the TGF-¿ type II receptor (Tgfbr2) in articular cartilage. Altered responsiveness to TGF-¿ resulted in a progressive skeletal disease that resembled osteoarthritis in humans. We recently identified several down-stream targets of TGF-¿ that regulate post-translational processing of the major extracellular matrix proteins in articular cartilage. One in particular, 3-Prime-Phoshoadenosine 5-Prime-Phosphosulfate Synthase 2 (Papss2), has been associated with Spondyloepimetaphyseal Dysplasias in humans and is required for proper sulfation of proteoglycans in cartilage. In addition to TGF-¿, the transcription factor Sox9 is also associated with the maintenance of mature articular cartilage. Our preliminary studies indicate that TGF-¿ enhances the level of Sox9 protein in chondrocytes independently of changes in mRNA. The preliminary data suggest that treatment with TGF-¿ results in sumoylation of Sox9. Sumoylation has been shown to regulate protein stability, activity and cellular localization. We hypothesize that TGF-¿ maintains the differentiated chondrocyte phenotype in permanent cartilages, like articular cartilage, by regulating Sox9 levels and activity via protein sumoylation. We propose to test this model with the following specific aims: 1a) to determine which sites on Sox9 are sumoylated in response to TGF-¿ and determine the role of sumoylation in TGF-¿-mediated Sox9 levels, localization, and activity; 1b) to determine the mechanism of TGF-¿-mediated sumoylation of Sox9; 2) to determine the mechanism of TGF-¿ mediated expression of Papss2 and 3) to determine if Papss2 activity can alleviate cartilage degeneration when TGF-¿ signaling is disrupted and determine if activation of TGF-¿'s chondroprotective signals can restore biochemical and biomechanical properties to OA cartilage. These studies will identify mechanisms of chondroprotection that can be used as targets for therapies in osteoarthritis.

描述（由适用提供）：骨关节炎是工业化世界中残疾的主要原因，但对与骨关节炎相关的软骨破坏机制知之甚少。小鼠遗传操作的最新进展导致了与了解人类骨关节炎有关的新动物模型和新概念。我实验室的长期目标是了解介导关节软骨的发育，持久性和修复的因素，并确定针对骨关节炎的预防和治疗策略的特定目标。 TGF- - 是一种多功能肽，已被证明可以调节细胞分化和组织特异性基因表达。以前，我们产生的转基因小鼠表达了关节软骨中TGF-€II受体（TGFBR2）的显性阴性突变。对TGF-的反应改变导致一种类似于人类骨关节炎的进行性骨骼疾病。我们最近确定了TGF- - 调节关节软骨中主要细胞外基质蛋白的翻译后处理的几个下游靶标。尤其是，一种3-杆磷脂5-磷脂硫酸盐合酶2（PAPSS2）与人类中的脊椎皮phicepichepipimeteal异常发育不良相关，并且是在软骨中正确硫酸蛋白糖的适当硫酸。除TGF- - 外，转录因子SOX9还与成熟关节软骨的维持有关。我们的初步研究表明，TGF- - 与mRNA的变化无关，在软骨细胞中增强了Sox9蛋白的水平。初步数据表明，用TGF- - 治疗导致SOX9的sumoylation。已证明Sumoylation调节蛋白质稳定性，活性和细胞定位。我们假设TGF-坚持 通过蛋白质Sumoylation控制SOX9水平和活性，在永久软骨（如关节软骨）中分化的软骨细胞表型（如关节软骨）。我们建议以以下特定目的测试该模型：1a）确定SOX9上的哪些位点是对TGF- - 响应的sumoylly，并确定Sumoylation在TGF-介导的SOX9水平，本地化和活动中的作用； 1b）确定tgf -¿介导的sux9的机理； 2）确定TGF-介导的PAPSSS和3）确定PAPSS2活性是否可以减轻TGF- - 信号传导时是否可以减轻软骨变性，并确定TGF- - tgf-®的软骨机构信号是否可以恢复生物化学和生物力学特性，以恢复OA的生物力学特性。这些研究将确定软骨保护的机制，可以用作骨关节炎疗法的靶标。