CAREER: Linking systemic stem cell activation to vertebrate limb regeneration

职业：将全身干细胞激活与脊椎动物肢体再生联系起来

• 批准号: 2145925
• 负责人: Jessica Whited
• 金额: $ 101.24万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-15 至 2026-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2145925&HistoricalAwards=false
• 关键词: CAREER; Linking; systemic; stem; cell

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117- 2). Salamanders can completely regenerate their legs following amputation throughout life. How they regenerate is still mysterious despite centuries of research. Humans and other mammals have very limited natural limb regeneration abilities, restricted to just the very tips of the fingers and toes. Meanwhile, some invertebrates, like planarians, can regrow almost every body part. The huge variation in regenerative ability is also not well understood. This project aims to fill in missing information about how salamanders regenerate limbs. It will also address how similar these processes in salamanders are to regenerative processes in other super-regenerators and to injury responses in mammals. A systemic response to amputation was recently discovered in axolotl salamanders in which some cells throughout the body are activated to make new cells. The identity and function of these cells will be addressed. Recent data also indicates the nervous system transmits signals that distant cells use to sense an amputation. This project will test several molecules detected in nerves to determine if they are required for the body-wide injury response. It will also address the role of molecules that travel in the blood in transmitting amputation injury signals in axolotls. Finally, the project will examine molecules important for body-wide injury responses in planarians and mice in the axolotl context. Together, these experiments will build understanding of how systemic responses are linked to local regeneration of a body part. They will also fill in gaps in knowledge about evolution of regenerative processes, and they will inform future regenerative medicine approaches. This project will also train many undergraduate students in a new course and through a laboratory exchange program. Finally, it will reach out to the public with a weekly web documentary that interviews scientists from diverse backgrounds.With the recent application of a variety of molecular genetic tools in axolotl, amputation responses and subsequent limb regeneration can finally be understood at a mechanistic level. This project seeks to define the connections between systemic progenitor cell activation, defined as cell-cycle re-entry, and limb regeneration in axolotl. The fate and identity of systemically-activated cells will be investigated using integrative retroviruses in vivo as well as transgenic axolotls and single-cell RNA-seq. The specific roles of the nervous and circulatory systems in systemic activation will also be examined experimentally, using both gain-of-function and loss-of-function approaches, and building on RNA-seq data from peripheral nerves and responding tissues as well as plasma proteomics. The project will also test for possible conserved roles of previously identified factors in injury responses in both planarians and mice, such as EGR1, Wnts, and HGF, in the axolotl system. Together, these experiments will inform a developing model in which systemic injury responses may represent ancestral processes that have been differentially elaborated upon at the local injury site during evolutionary time, manifesting in a large range of regenerative outcomes in extant species.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该奖项全部或部分根据2021年美国救援计划法案（公法117- 2）资助。蝾螈在截肢后可以在一生中完全再生腿。 尽管经过几个世纪的研究，它们如何再生仍然是个谜。 人类和其他哺乳动物的肢体再生能力非常有限，仅限于手指和脚趾的尖端。 与此同时，一些无脊椎动物，如真涡虫，几乎可以再生身体的每一个部位。 再生能力的巨大差异也没有得到很好的理解。 该项目旨在填补关于蝾螈如何再生肢体的缺失信息。 它还将解决如何相似的蝾螈这些过程是在其他超级再生器的再生过程和哺乳动物的损伤反应。 最近在蝾螈中发现了截肢的全身反应，其中全身的一些细胞被激活以产生新的细胞。 这些细胞的身份和功能将得到解决。 最近的数据还表明，神经系统传输信号，远距离细胞使用这些信号来感知截肢。 该项目将测试在神经中检测到的几种分子，以确定它们是否是全身损伤反应所需的。 它还将解决在血液中传播的分子在蝾螈中传递截肢损伤信号的作用。 最后，该项目将检查分子的重要性，全身损伤反应的涡虫和小鼠的美西螈的背景下。 总之，这些实验将建立对全身反应如何与身体部位的局部再生相联系的理解。 它们还将填补有关再生过程进化的知识空白，并为未来的再生医学方法提供信息。 该项目还将通过一个实验室交换项目，在一个新的课程中培训许多本科生。 最后，它将通过每周一次的网络纪录片与公众接触，该纪录片采访了来自不同背景的科学家。随着最近各种分子遗传工具在美西螈中的应用，截肢反应和随后的肢体再生终于可以在机械水平上得到理解。 该项目旨在确定系统祖细胞激活（定义为细胞周期重新进入）与美西螈肢体再生之间的联系。 将使用体内整合逆转录病毒以及转基因蝾螈和单细胞RNA-seq研究系统激活细胞的命运和身份。 神经和循环系统在全身激活中的具体作用也将通过实验进行研究，使用功能获得和功能丧失方法，并建立在来自外周神经和响应组织以及血浆蛋白质组学的RNA-seq数据的基础上。 该项目还将测试先前确定的因素在涡虫和小鼠的损伤反应中可能的保守作用，如EGFR 1，Wnts和HGF，在蝾螈系统中。 总之，这些实验将为一个发展中的模型提供信息，在该模型中，全身性损伤反应可能代表在进化过程中局部损伤部位差异化的祖先过程，该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查进行评估来支持的搜索.