IDENTIFYING ROADBLOCKS TO LIMB REGENERATION

识别肢体再生的障碍

• 批准号: 10401572
• 负责人: JESSICA L. WHITED
• 金额: $ 3.64万
• 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/10401572
• 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.

项目概要（摘要） 人类的肢体自然再生能力极其有限。因受伤或疾病而丧失肢体 是一个主要的健康问题。目前约有 200 万美国人承受着肢体丧失的后果， 由于糖尿病和其他主要危险因素的患病率增加，预计这一数字还会上升。 影响脉管系统的疾病。截肢的后果对患者来说是深远的，大多数人必须 依靠假肢，但假肢并不完美。如果再生医学方法有一天可能是可行的 了解如何自然地实现全肢置换。为了获得这种理解，我们 采用动物模型蝾螈，它可以在以下情况下完全再生四肢 截肢，即使是成年人。蝾螈的四肢在解剖学上与人类四肢相似，并且它们的最初发育 也类似。因此，它们为复杂的三维肢体如何再生和再生提供了蓝图。 截肢后功能性地融入现有残肢。如果出现这种情况，必须解决的关键问题 范式将被转化为人类论坛，即蝾螈如何激活和培育祖先 新肢体。此外，可能会对抗成功再生的细胞和分子力 还必须理解，因为这些通常可能存在于人类患者中，从而阻碍再生。 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存在。 在哺乳动物中被激活，或者它们是否过早终止，或者它们是否被其他物质明显阻断 因素。方法是先彻底了解肢体如何再生，然后再使用它 为未来可能的疗法提出假设的信息。 在这项提案中，我们利用了我们最近的发现，即蝾螈的能力可能会受到损害 反复截肢后肢体再生。这一发现为识别因素提供了独特的机会 这可能会限制再生或可能拮抗再生。我们将检查祖细胞的激活 连续截肢后确定这些细胞是否因再生失败而耗尽。我们也会 考虑巨噬细胞和肌成纤维细胞在反复截肢后再生失败中的作用。我们 将测试我们发现的再生限制是否在局部水平上起作用，在肢体本身内并接近 截肢部位，或者如果它们作用更系统，则在身体其他部位。最后，我们将调查 重复截肢后表达失调的两个基因的活性，双调蛋白 和眼睛缺席 2，两者都与人类相关。这项研究将利用以下机会 我们的新模型提出了希望加深对再生限制的理解 对于未来患者的再生医学方法至关重要。