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，引导其向某种终末细胞类型分化的新材料将在再生医学的新兴领域发挥重要作用。提出的工作详细介绍了在三维支架内诱导人间充质干细胞（hMSCs）分化为成骨细胞谱系的策略，并应用于骨再生。拟议的支架将由肽两亲体（PAs）组成，这是一种完全由常见生物成分（肽和脂肪酸）制成的合成材料。众所周知，这里描述的家族PAs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的细胞外基质的纤维凝胶。PAs将配备地塞米松（Dex）通过可水解的腙连接结合到PA。众所周知，Dex可以在二维培养中诱导hMSCs成骨，但一种可注射的三维释放Dex的凝胶能够分化hMSCs并支持其体内增殖，目前还没有报道。一旦合成了释放Dex的PA，在没有细胞的情况下，将测量从PA凝胶到缓冲液中的Dex释放量。零级水解的腙键预计释放Dex缓慢，持续的方式。在确定释放动力学后，将在提议的dex释放凝胶中三维培养hMSCs，该凝胶将用稀释剂PA构建以提供结构支持。凝胶的表征将通过电子显微镜、小角度x射线散射、流变性和圆二色性来完成。结合染色、基因表达和蛋白表达来量化成骨和矿物质产生的程度。与释放dex的PA同时，一种显示模仿生长因子骨形态发生蛋白2 （BMP-2）肽序列的PA也将被开发。拟制的bmp -2模拟PA可能与释放dex的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。几个体外实验将进行比较两种方法的成骨，通过不同的细胞途径发挥作用。如果成功，本研究开发和研究的释放dex和模拟bmp -2的PA支架可以作为可注射材料与hMSCs一起用于人类骨发育。这种治疗可以极大地改善由于骨缺损、癌骨切除或骨质疏松性骨折导致的骨再生能力严重受损的患者的生活质量。