Role of Shh/Brachyury axis in the maintenance of the postnatal intervertebral disc

Shh/Brachyury 轴在产后椎间盘维持中的作用

• 批准号: 10596619
• 负责人: Chitra L Dahia
• 金额: $ 55.17万
• 依托单位: HOSPITAL FOR SPECIAL SURGERY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-17 至 2026-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10596619
• 关键词: Absenteeism at work; Acceleration; Adult; Affect; Age; Age Months; Aging; Agonist; Alleles; Appearance; Back Pain; Biological Assay; Brachyury protein; Cell Count; Cell Differentiation process; Cell Proliferation; Cells; Chondrocyte-like Cell; Chondrocytes; Chronic low back pain; Chronology; DISC components; Data; Development; Differentiation and Growth; Disease; Embryo; Epiphysial cartilage; Exhibits; Extracellular Matrix; Financial Hardship; Gene Expression; Genes; Genetic; Genetic Transcription; Goals; Growth; Health; Heterogeneity; Human; In Vitro; Individual; Injury; Intervertebral disc structure; Knock-out; Knowledge; Learning; Maintenance; Microscopic; Modeling; Molecular; Mus; Pain; Palliative Care; Pathologic; Pathology; Phenotype; Population; Population Heterogeneity; Process; Reporter; Research; Risk Factors; Role; SHH gene; Signal Transduction; Structure; Testing; Therapeutic; Therapeutic Uses; Time; Visualization; Wages; age related; aged; cartilaginous; conditional knockout; differential expression; effective therapy; emotional distress; in vivo; insight; intervertebral disk degeneration; knock-down; mouse model; neonatal mice; notochord; novel; nucleus pulposus; overexpression; postnatal; postnatal development; prevent; small molecule; smoothened signaling pathway; spine bone structure; therapeutic development; transcription factor; transcriptome; transcriptome sequencing; translational study

PROJECT SUMMARY/ ABSTRACT The goal of this proposal is to identify the role of critical developmental molecules in growth and maintenance of the postnatal intervertebral disc (IVD, or disc), and how the loss of these molecules with age results in pathological changes in the disc. The disc is a cartilaginous structure present between each vertebra. The disc has three components: notochord derived central nucleus pulposus (NP), surrounded by orthogonal layers of annulus fibrosus (AF), and endplate (EP) adjacent to the growth plate. With age or injury, the disc undergoes degenerative changes leading to chronic lower back pain (cLBP) affecting almost 80% of the adult US population. Much remains to be learned about the cellular and molecular basis of disc growth differentiation, and aging, that has limited development of effective therapies. We will use conditional genetic mouse models, lineage-tracing, and disc injury models to identify the function(s) of a crucial developmental regulator Brachyury (Bra) in the disc. Our central hypothesis is that Bra-expression by the NP cells is essential for disc growth and maintenance, and its loss during aging leads to the pathological changes in the disc. BRA is a T-box transcription factor and a notochordal marker. Previously, we showed that postnatal NP cells express Bra; but it’s expression decreases with age. We also found that sonic hedgehog (SHH), an important notochord signal secreted by NP cells, regulates postnatal disc growth and differentiation, and regulates Bra expression. While the total number of NP cells decreased with age, the Bra-expressing NP cells also decreased with age and were replaced by non-Bra-expressing "chondrocyte-like cells" (CLCs). The lineage relationship between CLCs and the Bra-expressing cells they replace is unknown, nor is it known how (or if) the loss of Bra expression leads to disc aging. Our preliminary data showed that all NP cells are lost in an aged mouse disc. We also showed that conditional targeting of Shh in adult mouse accelerates disc aging, along with the loss of Bra expression. We further showed that haploinsufficiency of Bra accelerates disc aging, providing the logical premise for this new project. Aim 1 tests the hypothesis that Bra is a primary transcriptional regulator downstream of SHH signaling, and regulates growth and maintenance of postnatal disc. Aim 2 will test the hypothesis that NP cells diverge into two molecularly heterogeneous populations, which differ with respect to Shh and Bra expression. Aim 3 will test the hypothesis that Bra controls the survival of NP cells, and prevents them from differentiating into "chondrocyte-like" cells. We expect that the findings from this study will provide insights into the role of developmental molecules in the maintenance of postnatal disc during growth and aging, and will identify avenues for targeting such molecules to reverse the aging process, aiding the development of therapeutics for the treatment of disc related disorders and LBP.

项目摘要/摘要 该提案的目的是确定关键发展分子在增长和维持中的作用 出生后椎间盘（IVD或椎间盘）的 椎间盘是每个椎骨之间存在的软骨结构。光盘 有三个组成部分：脊索衍生的中央核（NP），周围是正交层 纤维纤维（AF）和末端板（EP）与生长板相邻。随着年龄或伤害，光盘经历 退化性变化导致慢性下背部疼痛（CLBP）影响了几乎80％的成人美国 人口。关于椎间盘生长分化的细胞和分子基础还有很多尚待了解， 和衰老，这有限的有效疗法发展。我们将使用条件遗传小鼠模型， 谱系追踪和椎间盘损伤模型，以识别关键发育调节剂的功能 （胸罩）在光盘中。我们的中心假设是，NP细胞对椎间盘生长和 维护及其在衰老期间的损失会导致椎间盘的病理变化。胸罩是T-box 转录因子和脊索标记。以前，我们表明产后NP细胞表达胸罩。但 表达随着年龄的增长而下降。我们还发现Sonic刺猬（SHH），一个重要的脊索信号 由NP细胞分泌，调节产后椎间盘的生长和分化，并调节胸罩表达。尽管 NP细胞的总数随着年龄的增长而减少，表达胸罩的NP细胞也随着年龄的增长而降低 被非表达BRA的“软骨细胞样细胞”所取代（CLCS）。 CLC之间的血统关系 它们替换的表达胸罩的单元格是未知的，也不知道（或者）如何（或者）丢失胸罩表达 导致椎间盘衰老。我们的初步数据表明，所有NP细胞在老年小鼠盘中都丢失。我们也是 表明成年小鼠中SHH的条件靶向加速椎间盘老化，而胸罩的丢失 表达。我们进一步表明，胸罩的单倍不足会加速椎间盘老化，提供逻辑 这个新项目的前提。 AIM 1检验了胸罩是主要转录调节剂的假设 SHH信号的下游，调节产后椎间盘的生长和维护。 AIM 2将测试 NP细胞分解成两个分子异质种群的假说，相对于 SHH和胸罩表达。 AIM 3将测试胸罩控制NP细胞存活的假设，并防止 它们从分化为“软骨细胞样”细胞。我们希望这项研究的发现将提供 洞悉发育分子在生长和衰老过程中维持产后椎间盘的作用， 并将确定靶向这种分子以扭转衰老过程的途径 治疗椎间盘相关疾病和LBP的治疗剂。