Mechanobiology of fracture healing during skeletal disuse

骨骼废用期间骨折愈合的力学生物学

• 批准号: 10723764
• 负责人: Evan G Buettmann
• 金额: $ 11.21万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10723764
• 关键词: Acute; Affect; Aging; Attenuated; Award; Bed rest; Bioinformatics; Biomechanics; Blood Vessels; Bone Injury; Bone Regeneration; Bone callus; Burn injury; Cell Lineage; Cells; Clinical; Coupling; Data; Development; Diabetes Mellitus; Disease; Down-Regulation; Electric Stimulation; Environment; Flow Cytometry; Fracture; Genes; Genetic; Genetic Engineering; Grant; Health; Hindlimb Suspension; Hormonal; Impairment; In Vitro; Incidence; Individual; Intervention; Knowledge; Light; Mechanics; Mediator; Mentors; Modality; Modeling; Molecular; Mus; Muscle; Muscle Contraction; Muscle Weakness; Muscular Atrophy; Musculoskeletal; Obesity; Osteoblasts; Osteocytes; Osteogenesis; Outcome; Pain; Paralysed; Pathology; Pathway interactions; Patient-Focused Outcomes; Patients; Pharmaceutical Preparations; Phase; Physical Rehabilitation; Physiologic pulse; Population; Pre-Clinical Model; Process; Proteins; Recovery; Regimen; Rehabilitation therapy; Reporting; Research; Risk; Role; Signal Transduction; Skeletal Muscle; Space Flight; Techniques; Testing; Tissues; Training; Transcript; Transcriptional Coactivator with PDZ-Binding Motif; Verteporfin; Weight-Bearing state; Work; angiogenesis; bone; bone cell; bone fracture repair; bone healing; bone loss; bone mass; bone repair; career; cell type; deprivation; fall risk; falls; fracture risk; fragility fracture; healing; high risk; improved; in vivo; insight; limb bone; mechanical load; mortality; mouse model; muscle form; muscle strength; optogenetics; osteoclastogenesis; osteogenic; osteoimmunology; protein activation; radiological imaging; reduced muscle mass; repaired; skeletal; skeletal muscle wasting; skills; stem cell proliferation; targeted treatment; transcriptome sequencing; virtual

PROJECT SUMMARY/ABSTRACT Decreased muscle and bone mass and strength resulting from musculoskeletal unloading (disuse osteosarcopenia) has long been associated with increased fracture risk, impaired bone healing and worse patient outcomes. Current disease modifying drugs are centered primarily on bone targeted therapies (anti- resorptives and PTH), and remain ineffective at targeting muscle loss that appears crucial for healthy bone repair and reducing fall risk. Although early reambulation and physical rehabilitation following bone injury is known to be beneficial for fracture healing and muscle recovery, there remains a gap in our knowledge of the appropriate mechanical loading regimens following osteosarcopenic fracture due to limited knowledge of how disuse affects fracture healing mechanobiology. In preliminary work, we have a developed a murine model of fracture healing during disuse by hindlimb unloading, with and without remobilization. This model recapitulates many clinical features of bone repair during disuse (decreased skeletal muscle mass, decreased radiographical callus formation) with new findings such as altered callus vascularity and osteoclastogenesis that are attenuated with reambulation. The aims outlined in this proposal seek to greatly expand upon our preliminary studies by using non-invasive loading modalities targeting muscle and or bone directly to determine the critical cellular and molecular mediators of callus mechanobiology during disuse. In the mentored K99 portion of this grant, we will utilize non-invasive optogenetics and direct tibial loading to determine optimal mechanical inputs to increase callus healing, biomechanical integrity, and muscle mass during disuse (Aim 1). Next using high-throughput techniques (RNAseq and flow cytometry), we will investigate the potential underlying mechanisms by which non-invasive loading affects callus mechanobiology during disuse (Aim 2). During the R00 phase, Dr. Buettmann will leverage recent mechanistic findings to determine the conditional role of mechanosensitive molecules in coordinating load-induced alterations in fracture healing during disuse (Aim 3). These insights will help bridge a significant gap in our understanding of how disuse alters callus mechanobiology and how mechanically-regulated molecules can be leveraged to improve fracture healing and rehabilitation in osteosarcopenic “high risk” patients. These findings, owing to the preclinical model’s translatability, could also have far-reaching implications for other pathologies associated with impaired fracture healing and altered mechanosensation such as aging, obesity/diabetes, and hormonal deprivation. Dr. Buettmann has assembled a mentoring team and collaborators with expertise in bone regeneration/osteoimmunology (Drs. Olivares-Navarrete), optogenetics and muscle-bone mechanoregulation (Dr. Megan Killian), musculoskeletal bioinformatics (Dr. Charles Farber), biomechanics (Dr. Hannah Dailey) and mechanobiology (Dr. Henry Donahue). This project will prepare Dr. Buettmann for an independent research career in musculoskeletal research by acquiring the necessary training and research data for an R01 equivalent award.

项目总结/摘要 由于肌肉骨骼卸载（废用）导致肌肉和骨骼质量及强度下降 骨质疏松症）长期以来与骨折风险增加、骨愈合受损以及更严重的 患者结局。目前的疾病修饰药物主要集中在骨靶向治疗（抗肿瘤药物）上。 吸收剂和甲状旁腺激素），并保持无效的目标肌肉损失，似乎对健康的骨骼至关重要 修复和降低跌倒风险。虽然骨损伤后的早期修复和身体康复是 已知有益于骨折愈合和肌肉恢复，但我们对骨折愈合和肌肉恢复的认识仍然存在差距。 由于对如何进行机械载荷的了解有限，导致骨缺血性骨折后采用适当的机械载荷方案 废用影响骨折愈合机械生物学。在初步工作中，我们已经开发了一种小鼠模型， 骨折愈合期间废用后肢卸载，有和没有再动员。该模型概括了 废用期间骨修复的许多临床特征（骨骼肌质量减少、减少 X线骨痂形成），并有新的发现，如骨痂血管分布和破骨细胞生成改变 这些都是用抗生素减弱的。本提案中概述的目标旨在大大扩展我们的 通过使用直接针对肌肉和/或骨骼的非侵入性加载方式来确定 废用过程中愈伤组织机械生物学的关键细胞和分子介质。在K99的指导下 在这笔赠款的一部分，我们将利用非侵入性光遗传学和直接胫骨负荷，以确定最佳的 机械输入以增加废用期间的骨痂愈合、生物力学完整性和肌肉质量（目标1）。 接下来，我们将使用高通量技术（RNAseq和流式细胞术）， 非侵入性负荷影响废用过程中骨痂机械生物学的潜在机制（目的2）。 在R 00阶段，Buettmann博士将利用最近的机制发现来确定条件性 机械敏感分子在协调废用期间骨折愈合中负荷诱导的变化中的作用 (Aim 3）。这些见解将有助于弥合我们对废用如何改变愈伤组织的理解的重大差距 机械生物学以及如何利用机械调节分子来改善骨折愈合， 骨肉瘤“高危”患者的康复。这些发现，由于临床前模型的 可翻译性，也可能对其他与受损骨折相关的病理学产生深远的影响。 愈合和机械感觉改变，如衰老、肥胖/糖尿病和激素缺乏。博士 Buettmann组建了一个指导团队和具有骨骼专业知识的合作者 再生/骨免疫学（Olivares-Navarete博士），光遗传学和肌肉-骨骼机械调节 (Dr. Megan Killian）、肌肉骨骼生物信息学（Charles Farber博士）、生物力学（Hannah Dailey博士） 和机械生物学（亨利多纳休博士）。该项目将为Buettmann博士的独立研究做准备。 通过获得R 01所需的培训和研究数据，在肌肉骨骼研究领域开展研究工作 相等的奖励。