Osteocyte Mechanotransduction and the Gabapentin-Sensitive Matrix-Channel Tethering Complex

骨细胞机械转导和加巴喷丁敏感基质通道束缚复合物

• 批准号: 9789654
• 负责人: William Roy Thompson
• 金额: $ 57.7万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-20 至 2023-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9789654
• 关键词: Ablation; Acute; Address; Affinity; Alleles; Antiepileptic Agents; Behavior; Binding; Biochemical; Biochemistry; Biological; Bone Matrix; Bone Resorption; C57BL/6 Mouse; Calcium Channel; Cell membrane; Cell surface; Cells; Chronic; Clinical; Complex; Confocal Microscopy; Cues; Disease; Elements; Foundations; Fracture; Genetic; Heparan Sulfate Proteoglycan; Histologic; Hormonal; Image; Impairment; In Vitro; Knockout Mice; Ligands; Liquid substance; LoxP-flanked allele; Maintenance; Measures; Mechanics; Membrane; Methods; Minerals; Molecular; Morbidity - disease rate; Mus; Musculoskeletal; Neuropathy; Osteoblasts; Osteoclasts; Osteocytes; Osteogenesis; Osteopenia; Patients; Pharmaceutical Preparations; Pharmacology; Positioning Attribute; Protocols documentation; Regimen; Rehabilitation therapy; Research Design; Signal Transduction; Skeleton; Stimulus; Structure; Surface Plasmon Resonance; System; Techniques; Time; Tissues; Work; bone; bone cell; bone loss; bone mass; bone quality; bone strength; density; dentin matrix protein 1; design; disability; extracellular; fracture risk; gabapentin; genetic approach; in vivo; insight; knock-down; mechanical force; mechanical load; mechanotransduction; mouse model; novel; novel strategies; painful neuropathy; perlecan; preservation; prevent; receptor; response; sedentary lifestyle; side effect; skeletal; voltage

Project Summary The skeleton relies on a variety of mechanical, biochemical, and hormonal cues to regulate bone strength, structure, and mass. Osteocytes are both the most abundant and most mechanosensitive cells within bone. Located deep in the bone matrix, these cells are optimally positioned to sense and respond to force, directing the activity of other skeletal cells, including osteoblasts and osteoclasts. A variety of molecules influence osteocyte mechanosensation; however, how force is directly transmitted from the mineralized matrix to the cell membrane to induce a biological response remains unknown. We have identified the presence of a complex within osteocytes composed of extracellular perlecan/HSPG2 and a cell surface subunit (a2d1) of voltage sensitive calcium channels (VSCCs). As the perlecan-containing tethers bind the a2d1 subunit of VSCCs, this Matrix-Channel Tethering Complex (M-CTC) enables direct connection between the mineralized matrix and the cell membrane. Thus, the proposed studies will dissect how this mechanosensory complex mechanistically regulates osteocyte behavior, under both basal and mechanical loading conditions. Additionally, the a2d1 subunit of the complex is the receptor for the commonly used antiepileptic and neuropathic pain drug, gabapentin, which can have severe adverse skeletal side effects. Thus, this work will not only investigate the foundational mechanisms through which osteocytes sense force, but will also inform the design of novel strategies to offset the negative effects of gabapentin on bone that reduce bone mass. Our overarching hypothesis is that perlecan-containing tethers, within the M-CTC, transmit force to the a2d1 subunit of VSCCs, enabling mechanical signals to be transduced into anabolic biochemical responses in osteocytes. Aim 1: Determine if osteocyte-specific disruption of the M-CTC membrane receptor a2d1 impairs basal or load-induced bone formation with resultant loss in bone quality. Aim 2: Determine if tissue-specific genetic ablation of the PLN matrix tethers within the M-CTC of osteocytes impairs basal or load-induced bone formation with resultant loss in bone quality. Aim 3: Determine how gabapentin interferes with the M-CTC to impair basal and load-induced bone formation. The function of the M-CTC has not been explored in vivo. As such, these integrated studies, designed to genetically and pharmacologically disrupt the M-CTC and assess the functional consequences, will provide basic insights into the relationship between extracellular tethers and calcium channels in bone. In the long term, this understanding may reduce bone loss in patients treated with gabapentin for neuropathic pain.

项目摘要 骨骼依赖于各种机械、生化和激素信号来调节骨骼强度， 结构和质量。骨细胞是骨组织中数量最多、力学敏感性最高的细胞。 位于骨基质深处，这些细胞处于最佳位置，可以感知和响应力， 其他骨骼细胞的活性，包括成骨细胞和破骨细胞。多种分子影响 骨细胞机械感觉;然而，力如何直接从矿化基质传递到细胞 膜诱导生物反应仍然未知。我们发现了一种复杂的 在骨细胞内，由细胞外串珠素/HSPG 2和细胞表面电压亚基（a2 d1）组成， 敏感钙通道（VSCC）。由于含串珠素的系链结合VSCC的a2 d1亚基， 基质-通道栓系复合物（M-CTC）使矿化基质和细胞之间的直接连接成为可能。 细胞膜因此，拟议的研究将剖析这种机械感觉复合体如何在机械上 在基础和机械负荷条件下调节骨细胞行为。此外，A2 D1 复合物的亚基是常用的抗癫痫和神经性疼痛药物的受体， 加巴喷丁，它可能有严重的不良骨骼副作用。因此，这项工作不仅将调查 骨细胞感知力的基本机制，但也将告知新的设计。 抵消加巴喷丁对骨的负面影响，减少骨量的策略。 我们的总体假设是，在M-CTC内，含有串珠素的系链将力传递到a2 d1 VSCC的亚基，使机械信号能够被转导到合成代谢生化反应中， 骨细胞 目的1：确定M-CTC膜受体a2 d1的骨细胞特异性破坏是否损害了基础免疫功能。 或负荷诱导的骨形成导致骨质量损失。 目的2：确定M-CTC内PLN基质系链的组织特异性遗传消融是否可用于 骨细胞损害基础或负荷诱导的骨形成，导致骨质量的损失。 目的3：确定加巴喷丁如何干扰M-CTC损害基础骨和负荷诱导骨 阵 尚未在体内探索M-CTC的功能。因此，这些综合研究旨在 遗传和免疫破坏M-CTC并评估功能后果，将提供 对细胞外系链和骨钙通道之间关系的基本认识。从长远 换句话说，这种理解可能会减少加巴喷丁治疗神经性疼痛患者的骨丢失。