3D Differentiation of Mesenchymal Stem Cells in Peptide Amphiphile Matrices

肽两亲基质中间充质干细胞的 3D 分化

• 批准号: 8202481
• 负责人: John B Matson
• 金额: $ 4.84万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2012-08-10
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8202481
• 关键词: 3-Dimensional; Adult; Area; Binding; Biological; Bone Development; Bone Growth; Bone Regeneration; Buffers; Cancerous; Cell Culture Techniques; Cells; Circular Dichroism; Defect; Dexamethasone; Dimensions; Electron Microscopy; Excision; Extracellular Matrix; Family; Fatty Acids; Future; Gel; Gene Expression; Growth Factor; Healed; Human; Hydrazones; Hydrolysis; Hydroxyapatites; In Vitro; Injectable; Kinetics; Lead; Malignant Neoplasms; Measures; Mesenchymal Stem Cells; Methods; Minerals; Nanostructures; Natural regeneration; Osteogenesis; Osteoporosis; Pathway interactions; Patients; Peptide Signal Sequences; Peptides; Pharmaceutical Preparations; Play; Production; Proteins; Quality of life; Regenerative Medicine; Reporting; Research; Rheology; Roentgen Rays; Role; Solutions; Staining method; Stains; Time; Trauma; Work; adult stem cell; aging population; analog; aqueous; bone; bone healing; bone morphogenic protein; cell type; controlled release; design; healing; improved; in vitro testing; in vivo; mimetics; nanofiber; novel; osteogenic; osteoporosis with pathological fracture; peptide A; protein aminoacid sequence; protein expression; research study; scaffold; stem cell differentiation; two-dimensional

DESCRIPTION (provided by applicant): New materials that are capable of interacting with adult stem cells to direct their differentiation toward a certain terminal cell type will play an important role in the emerging field of regenerative medicine. The proposed work details a strategy for inducing the differentiation of human mesenchymal stem cells (hMSCs) into osteoblastic lineage inside a three dimensional scaffold, with applications in bone regeneration. The proposed scaffold will be comprised of peptide amphiphiles (PAs), which are synthetic materials made entirely from common biological components (peptides and fatty acids). PAs of the family described here are well-known to form high aspect ratio nanofibers in aqueous solution, yielding a fibrous gel that resembles the extracellular matrix in nanostructure. PAs will be outfitted with dexamethasone (Dex) bound to the PA via a hydrolysable hydrazone linkage. Dex is well-known to induce osteogenesis of hMSCs in 2-dimensional culture, but an injectable, 3-dimensional, Dex-releasing gel capable of differentiating hMSCs and supporting their proliferation in vivo has never been reported. Once a Dex-releasing PA has been synthesized, Dex release will be measured from the PA gels into buffer in the absence of cells. Zero-order hydrolysis of the hydrazone bond is expected to release Dex in a slow, sustained manner. After release kinetics have been determined, hMSCs will be cultured in three dimensions inside the proposed Dex-releasing gel, which will be constructed with a diluent PA to provide structural support. Characterization of the gel will be accomplished using electron microscopy, small-angle X-ray scattering, rheology, and circular dichroism. A combination of staining, gene expression, and protein expression will be used to quantify the extent of osteogenesis and mineral production. In parallel with the Dex-releasing PA, a PA that displays a peptide sequence mimicking the growth factor bone morphogenic protein 2 (BMP-2) will also be developed. The proposed BMP-2-mimetic PA may function in synergy with the Dex-releasing PA, eventually yielding faster bone production and healing than either component alone. Several in vitro experiments will be performed to compare the two methods of osteogenesis, which function through different cellular pathways. If successful, the Dex-releasing and BMP-2-mimetic PA scaffolds developed and studied here may be used as injectable materials in conjunction with hMSCs for bone development in humans. Such a treatment may drastically improve the quality of life of patients with severely compromised bone regeneration capacities due to bone defects, removal of cancerous bone, or osteoporotic fractures. PUBLIC HEALTH RELEVANCE: Bone defects due to cancer, trauma, or osteoporosis are an increasing problem in the context of an aging population. The proposed research will investigate an injectable material that when mixed with adult mesenchymal stem cells may be capable of promoting bone regeneration when the body's natural regeneration capacity is compromised. The results of this work will inform future studies aimed at improving the quality of life of patients with severe bone defects.

描述（由申请人提供）：能够与成体干细胞相互作用以引导其向特定终末细胞类型分化的新材料将在再生医学的新兴领域中发挥重要作用。这项工作详细介绍了一种在三维支架内诱导人间充质干细胞（hMSCs）分化为成骨细胞系的策略，并将其应用于骨再生。拟议的支架将由肽两亲物（PA）组成，这是完全由常见的生物组分（肽和脂肪酸）制成的合成材料。众所周知，本文所述的PA家族在水溶液中形成高纵横比的纳米纤维，产生类似于纳米结构中的细胞外基质的纤维凝胶。PA将配备通过可水解的腙键与PA结合的地塞米松（Dex）。众所周知，Dex在二维培养中诱导hMSCs的成骨，但可注射的三维Dex释放凝胶能够分化hMSCs并支持其在体内的增殖从未报道过。一旦合成了释放Dex的PA，将在不存在细胞的情况下测量从PA凝胶到缓冲液中的Dex释放。预计腙键的零级水解将以缓慢、持续的方式释放Dex。在释放动力学已经确定后，将在所提出的Dex释放凝胶内三维培养hMSC，所述凝胶将用稀释剂PA构建以提供结构支撑。凝胶的表征将使用电子显微镜、小角X射线散射、流变学和圆二色性来完成。将使用染色、基因表达和蛋白质表达的组合来量化骨生成和矿物质产生的程度。与Dex释放PA平行，还将开发显示模拟生长因子骨形态发生蛋白2（BMP-2）的肽序列的PA。所提出的BMP-2模拟PA可能与Dex释放PA协同作用，最终产生比单独使用任何一种成分更快的骨生成和愈合。将进行几项体外实验以比较两种成骨方法，它们通过不同的细胞途径发挥作用。如果成功的话，这里开发和研究的Dex释放和BMP-2模拟PA支架可以用作可注射材料，与hMSC一起用于人类骨发育。这种治疗可以显著改善由于骨缺损、癌骨切除或骨质疏松性骨折而严重损害骨再生能力的患者的生活质量。 公共卫生相关性：在人口老龄化的背景下，由于癌症、创伤或骨质疏松症导致的骨缺损是一个日益严重的问题。拟议的研究将研究一种可注射材料，当与成人间充质干细胞混合时，当人体的自然再生能力受到损害时，该材料可能能够促进骨再生。这项工作的结果将为未来旨在改善严重骨缺损患者生活质量的研究提供信息。