Cell Responsive Hydrogels to Improve Functional Recovery after Spinal Cord Injury

细胞响应水凝胶可改善脊髓损伤后的功能恢复

• 批准号: 8909603
• 负责人: Christopher Matthew Madl
• 金额: $ 3.42万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2017-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8909603
• 关键词: Alkynes; Animals; Apoptotic; Axon; Azides; Biochemical; Biological Assay; Cell Culture Techniques; Cell Survival; Cell Transplants; Cells; Chemistry; Cicatrix; Collaborations; Computer Simulation; Contusions; Cues; Development; Diffusion; Elastin; Engraftment; Ensure; Environment; Enzyme Kinetics; Extracellular Matrix; Feedback; Gel; Gelatinase A; Goals; Growth; Growth Cones; Histology; Homeostasis; Hydrogels; Immunohistochemistry; In Situ; In Situ Nick-End Labeling; Inflammation; Inflammatory; Inflammatory Response; Injury; Kinetics; Label; Lead; Life; Mechanics; Modeling; Motivation; Mus; NAPVSIPQ peptide; Natural regeneration; Nerve; Nerve Regeneration; Neurites; Neuronal Differentiation; Neurons; Neuroprotective Agents; Outcome; Oxidative Stress; Patients; Peptide Hydrolases; Peptides; Plants; Play; Process; Production; Proteins; Quality of life; Rattus; Reaction; Reactive Oxygen Species; Recovery; Recovery of Function; Rodent; Rodent Model; Role; Serine Protease; Signal Transduction; Site; Spinal cord injury; Staining method; Stains; Stem cell transplant; Support System; Therapeutic; Tissues; Transplantation; Urokinase; animal imaging; axon growth; base; behavior test; data modeling; design; differential expression; improved; nerve stem cell; neurodevelopment; neuron development; neurotrophic factor; oxidative damage; protein expression; public health relevance; response; stem cell differentiation; stem cell fate; stem cell therapy; stem cells; therapeutic target; time use; tissue regeneration

 DESCRIPTION (provided by applicant): Throughout tissue development and homeostasis, cells dynamically interact with the extracellular matrix (ECM). However, most materials developed to regulate stem cell fate and facilitate tissue regeneration are primarily cell-instructive, providing mechanical and biochemical signals to cells, and are not cell-responsive, that is they do not respond to the changes elicited in the delivered cells. The majority of materials that are cell-responsive simply degrade in response to cell-secreted proteases. A material that reacts to specific phenotypic changes elicited upon stem cell differentiation, such as those that occur during development, remains to be developed. A potential therapeutic target for such a material is spinal cord injury (SCI). SCI often results in severely debilitating conditins for patients, with limited clinically available treatment options. Nerve regeneration is limited by the body's natural inflammatory response that rapidly replaces injured spinal cord tissue with scar tissue. Furthermore, this inflammatory process results in significant oxidative damage to the surviving neurons, which further hampers regeneration. The goal of this project is to remediate the damage caused by this inflammation by delivering neural stem cells (NSCs) at the injury site within a material that is both cell-instructive, facilitating engraftment and differentiation of the delivered cells, and cell-responsive, releasing a neuroprotective peptide in response to neuronal differentiation. In Specific Aim 1, I will synthesize a material that dynamically responds to NSC differentiation by releasing a neuroprotective peptide. The peptide will be conjugated to an elastin-like protein (ELP) via a proteolytically cleavable linker using azide-alkyne "click" chemistry. Urokinase plasminogen activator (uPA) is a serine protease known to play a role in neuronal development, as it is secreted from the growth cones of axons. I hypothesize that neuronal differentiation of NSCs cultured in ELP hydrogels will result in increased uPA activity, which in turn will selectively release the neuroprotective peptide upon neuronal differentiation. In Specific Aim 2, I will develop a computational model to refine the cel-responsive material design. A reaction-diffusion model with Michaelis-Menten kinetics will be used to simulate the release of the neuroprotective peptide, and the relevant parameters will be experimentally determined. The model will be validated by culturing and differentiating NSCs in the cell-responsive ELP hydrogels and subjecting the cells to oxidative stress. In Specific Aim 3, I will deliver NSCs in the cell-responsive hydrogels to injury sites in rodent SCI contusion models and evaluate functional recovery. Material retention will be assessed with live-animal imaging, and NSC survival, engraftment, and differentiation will be assessed by histology. Recovery will be evaluated by tracing the regenerating nerves and through behavioral testing. I hypothesize that the cell-responsive material will improve the viability of the transplanted NSCs, resulting in improved functional recovery in animals treated with the cell-responsive materials.

 描述（由适用提供）：通过组织发育和稳态，细胞与细胞外基质（ECM）动态相互作用。然而，大多数用于调节干细胞命运和促进组织再生的材料是原发性细胞结构性，为细胞提供了机械和生化信号，并且不是细胞响应性的，即它们对递送细胞中引起的变化没有响应。细胞响应性SCI的大多数材料通常会导致患者严重使人衰弱，临床上可用的治疗选择有限。神经再生受到限制 人体的自然炎症反应迅速用疤痕组织替代受伤的脊髓组织。此外，这种炎症过程会导致生存神经元的明显氧化损伤，从而进一步阻碍了再生。该项目的目的是通过在细胞结构性的材料中传递神经元（NSC）来补救这种感染所造成的损害，从而既具有细胞结构性，又支撑了交付的植入和分化。细胞和细胞反应性，释放神经保护肽 在特定目标1中，我将通过释放神经保护肽来合成一种动态响应NSC分化的材料。该肽将通过使用叠氮化物-alkyne“ Click” Chemistry的蛋白水解连接器通过蛋白水解的连接器将肽结合到弹性蛋白样蛋白（ELP）中。尿激酶纤溶酶原活化剂（UPA）是一种已知在神经元发育中起作用的丝氨酸蛋白，因为它是从轴突的生长锥中分泌的。我假设在ELP水凝胶中培养的NSC的神经元分化将导致UPA活性增加，而神经元分化后将有选择地释放神经保护肽。在特定目标2中，我将开发一个计算模型来完善响应性材料设计。使用Michaelis-Menten动力学的反应扩散模型将用于模拟神经保护肽的释放，并将通过实验确定相关参数。该模型将通过在细胞反应性ELP水凝胶中培养和区分NSC并使细胞遭受氧化应激来验证。在特定的目标3中，我将在啮齿动物SCI挫伤模型中的损伤部位传递NSC，并评估功能恢复。材料保留率将通过实时成像进行评估，NSC的存活，植入和分化将通过组织学评估。通过追踪再生神经和行为测试来评估恢复。我假设细胞反应材料将改善移植NSC的生存能力，从而改善用细胞反应材料处理的动物的功能恢复。