IDENTIFYING ROADBLOCKS TO LIMB REGENERATION

识别肢体再生的障碍

• 批准号: 10160644
• 负责人: JESSICA L. WHITED
• 金额: $ 35.19万
• 依托单位: HARVARD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10160644
• 关键词: 3-Dimensional; Adult; Affect; Ambystoma; American; Amphiregulin; Amputation; Anatomy; Animal Model; Animals; Attenuated; Bar Codes; Binding; Cell Cycle; Cell Proliferation; Cells; Chemicals; Complement; Complex; Cues; Data; Defect; Development; Diabetes Mellitus; Digit structure; Disease; Epidermal Growth Factor Receptor; Essential Genes; Event; Eye; FRAP1 gene; Failure; Future; Genes; Genetic; Goals; Health; Human; Immune; Injury; Life; Ligands; Limb structure; Mammals; Mediating; Modeling; Molecular; Muscle satellite cell; Myofibroblast; Natural regeneration; Organism; Patients; Phosphoric Monoester Hydrolases; Play; Prevalence; Process; Prosthesis; Regenerative Medicine; Research; Risk Factors; Role; Salamander; Site; Source; Structure; System; Testing; Therapeutic; Time; Tissues; Transcription Coactivator; Translating; Work; blastema; cell motility; exhaust; exhaustion; experimental study; gain of function; genetic analysis; genetic approach; in vivo; inhibitor/antagonist; insight; limb amputation; limb loss; limb regeneration; loss of function; macrophage; migration; novel; premature; prevent; progenitor; recruit; regeneration model; regenerative; response; single-cell RNA sequencing; stem cells; tissue regeneration; transcriptome sequencing; wound epidermis; wound healing; wound response

PROJECT SUMMARY (ABSTRACT) Humans have exceedingly limited natural limb regenerative abilities. Limb loss due to injury or disease is a major health problem. About two million Americans currently live with the consequences of limb loss, and this number is expected to rise because of increased prevalence of key risk factors such as diabetes and other diseases that affect vasculature. The consequences of amputation are profound for patients and most must rely on prosthetics, which are not perfect. A regenerative medicine approach may one day be feasible if it were understood how total limb replacement can be naturally achieved. To gain this understanding, we are employing an animal model, the axolotl salamander, which can completely regenerate limbs following amputation, even as adults. Axolotl limbs are anatomically similar to human limbs, and their initial development is similar as well. Thus, they offer a blueprint for how a complex, three-dimensional limb can be regrown and functionally integrated into the existing stump following amputation. Key issues that must be resolved if this paradigm is to be translated into the human forum are how axolotls activate and cultivate the progenitors for the new limb. Additionally, the cellular and molecular forces that might antagonize successful regeneration must also be understood as these might normally exist in human patients and thereby prevent regeneration. Future research could elucidate whether the molecular and cellular forces guiding these events are not activated in mammals, or whether they terminate prematurely, or whether they are overtly blocked by other factors. The approach is to first thoroughly understand how limbs do regenerate, and then later use this information to develop hypotheses for future possible therapies. In this proposal, we leverage our recent finding that axolotls can be compromised in their ability to regenerate limbs following repeated amputation. This finding presents a unique opportunity to identify factors that may be limiting in regeneration or may antagonize it. We will examine activation of progenitor cells following successive amputations to determine if these cells are exhausted in regenerative failure. We will also consider the role of macrophages and myofibroblasts in regenerative failure following repeated amputation. We will test if the regenerative limitations we uncovered operate at a local level, within the limb itself and close to the site of amputation, or if they act more systemically, elsewhere in the body. Finally, we will investigate the activities of two genes whose expression becomes dysregulated following repeated amputation, amphiregulin and eyes absent 2, both of which have human correlates. This research will capitalize on the opportunities presented by our new model with the hope that increased understanding of regenerative limitations will be essential for future regenerative medicine approaches in patients.

项目摘要（摘要） 人类的自然肢体再生能力极为有限。受伤或疾病引起的肢体损失 是一个主要的健康问题。目前约有200万美国人遭受肢体损失的后果，并且 由于关键危险因素（例如糖尿病和其他）的患病率增加，预计该数字将增加 影响脉管系统的疾病。截肢的后果对于患者而言是深远的，大多数必须 依靠假肢，这不是完美的。如果有一天，如果它是一种再生医学方法可能是可行的 了解如何自然地实现总肢体替代。为了获得这种理解，我们是 采用动物模型的Axolotl Salamander，可以完全再生四肢 截肢，即使是成年人。 Axolotl肢体在解剖学上与人类四肢相似，它们的最初发育 也相似。因此，他们为如何重新生成一个复杂的三维肢体提供了蓝图 截肢后功能集成到现有的树桩中。如果这是必须解决的关键问题 范式将被翻译成人类论坛 新的肢体。另外，可能拮抗成功再生的细胞和分子力 还必须理解为通常存在于人类患者中，从而防止再生。 未来的研究可以阐明指导这些事件的分子和细胞力是否不是 在哺乳动物中激活，或者是否过早终止，还是被其他人公开阻止 因素。该方法是首先彻底了解四肢如何再生，然后以后使用它 信息以为未来可能的疗法开发假设。 在此提案中，我们利用了最近的发现，即阿克索洛特人的能力可能会受到损害 重复截肢后再生四肢。这一发现为识别因素提供了一个独特的机会 这可能会限制再生或可能对其进行拮抗。我们将检查祖细胞的激活 截肢后，确定这些细胞是否在再生衰竭中筋疲力尽。我们也会 考虑截肢重复后，巨噬细胞和肌纤维细胞在再生衰竭中的作用。我们 将测试我们发现我们发现的再生限制是否在肢体本身内部运行，并接近 截肢的部位，或者如果它们在体内其他地方更全面地起作用。最后，我们将调查 反复截肢后两种基因的活性，其表达失调 不存在眼睛2，两者都有人类相关。这项研究将利用机会 由我们的新模型提出，希望对再生限制的更多理解将是 对患者的未来再生医学方法至关重要。