Blastema-independent Mechanism for Regeneration in Salamanders

蝾螈的不依赖胚基的再生机制

• 批准号: 10379572
• 负责人: David M. Gardiner
• 金额: $ 20.72万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-02-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10379572
• 关键词: Adult; Ambystoma; Ambystoma mexicanum; Amphibia; BMP7 gene; Biological Assay; Biological Models; Biology; Candidate Disease Gene; Cells; Data; Dermal; Dermis; Enzymes; Epidermis; Epigenetic Process; Event; Failure; Fibroblasts; Future; Gene Expression; Gene Expression Profiling; Genes; Genetic; Gland; Goals; HDAC10 gene; Hair follicle structure; Histologic; Histone Deacetylase; Human; Image; Injury; Knowledge; Ligands; Limb structure; Mammals; Mediating; Mesenchymal; Microscopy; Modeling; Molecular; Molecular Profiling; Multipotent Stem Cells; Natural regeneration; Nerve; Pathway interactions; Population; Process; Proteins; Role; Salamander; Shoulder; Signal Pathway; Signal Transduction; Signaling Molecule; Site; Skin; Study models; Sweat Glands; Testing; Thick; Time; Tissue Recombination; Tissues; Transcription Repressor; Translating; Work; Wound models; antagonist; appendage; base; blastema; bone morphogenic protein; cell type; confocal imaging; differential expression; gene repression; healing; innovation; insight; macrophage; novel; organ repair; prevent; progenitor; regenerative; single-cell RNA sequencing; skin regeneration; skin wound; tissue regeneration; transcription factor; transcriptome sequencing; wound; wound healing

PROJECT SUMMARY While human and other mammals are limited in their abilities to regenerate, the salamanders, including Ambystoma mexicanum (axolotl) are highly regenerative and have provided numerous insights into the mechanisms of organ repair. Upon injury, axolotls generate “blastema” tissue at the wound site, which harbors multipotent progenitors that engage in regenerative healing, contributing to multiple newly forming cell types. The inability of mammals to form multipotent blastema cells is commonly thought to be the key barrier to true regenerative wound healing. Axolotls can also regenerate skin, which normally consists of an epidermis, a two- layer dermis as well as many secretory glands. Contrary to the prevailing notion that complete tissue regeneration requires blastema, we now show that the axolotl skin regenerates without a blastema and that, in fact, blastema formation represses glandular skin regeneration. This application will focus on defining a novel cellular and signaling mechanism of blastema-independent skin regeneration in salamanders. To achieve this goal, this project will leverage the analytical strengths of the so-called Accessory Limb Model (ALM) – a highly tractable wound model system in axolotls that can be experimentally directed to either: (i) rapidly regenerate gland-containing skin without a blastema, or (ii) form a blastema when presented with a deviated nerve and display prominently delayed skin regeneration. Using a combination of live axolotl imaging, lineage tracing, single-cell RNA-seq, functional protein delivery, and gene perturbation assays in the ALM model, in our first aim we will establish if amphibian skin gland regeneration critically depends on epidermal-dermal interactions and if these interactions are prevented in blastema-forming wounds due to the immaturity of their fibroblasts. The second aim is to uncover new signaling and epigenetic mechanisms of gland neogenesis in regenerating skin. In particular, we will establish the activating role of the Bone Morphogenic Protein ligand BMP7 and the counterbalancing role of its antagonist GREMLIN and the activating role of Class II histone deacetylase HDAC10 – top-listed differentially expressed genes in our RNA- seq studies – on gland regeneration and skin fibroblast lineage maturation. The study premise is strong, based on substantial preliminary data. The proposed studies are significant because they will introduce amphibian skin as a novel model for studying mechanisms of skin regeneration and will advance knowledge on skin cell types in amphibians. The proposed studies are innovative because they will establish a novel paradigm of blastema-independent regeneration and will identify new skin regeneration-inducing epigenetic and signaling factors. Ultimately, we want to be able to translate new knowledge learned from this amphibian model system of blastema-independent skin regeneration to better understand skin regeneration mechanisms in mammals, whose tissues typically heal without a blastema.

项目概要 虽然人类和其他哺乳动物的再生能力有限，但蝾螈，包括 Ambystoma mexicanum (axolotl) 具有高度再生能力，并为研究提供了许多见解。 器官修复机制 受伤后，蝾螈会在伤口部位产生“胚芽”组织，其中含有 参与再生愈合的多能祖细胞，有助于形成多种新形成的细胞类型。 哺乳动物无法形成多能胚细胞通常被认为是真正的关键障碍 蝾螈也可以再生皮肤，通常由表皮、两层组成。 与完整组织的普遍观念相反。 再生需要胚基，我们现在表明蝾螈皮肤可以在没有胚基的情况下再生，并且在 事实上，芽基形成抑制腺体皮肤再生。 该应用将重点定义一种不依赖胚基的新型细胞和信号传导机制 为了实现这一目标，该项目将利用蝾螈的分析优势。 所谓的辅助肢体模型（ALM）——蝾螈中一种高度易处理的伤口模型系统，可以 实验目的是：（i）快速再生含有腺体的皮肤而没有芽基，或（ii）形成 当出现神经偏离时，胚芽会出现明显的皮肤再生延迟。 活体蝾螈成像、谱系追踪、单细胞 RNA 测序、功能性蛋白递送和基因的组合 ALM 模型中的扰动分析，我们的第一个目标是确定两栖动物皮肤腺是否再生 关键取决于表皮-真皮相互作用，以及这些相互作用是否在胚基形成过程中被阻止 第二个目标是发现新的信号传导和表观遗传。 特别是，我们将确定腺体新生在皮肤再生中的激活作用。 骨形态发生蛋白配体 BMP7 及其拮抗剂 GREMLIN 和 II 类组蛋白脱乙酰酶 HDAC10 的激活作用——我们的 RNA 中最重要的差异表达基因—— seq 研究 – 关于腺体再生和皮肤成纤维细胞谱系成熟。 研究前提是强有力的，基于大量的初步数据。 意义重大，因为他们将引入两栖动物皮肤作为研究皮肤机制的新模型 再生并将增进对两栖动物皮肤细胞类型的了解。拟议的研究具有创新性。 因为他们将建立一种不依赖胚基的再生的新范例，并将识别新的皮肤 最终，我们希望能够转化新的表观遗传和信号因子。 从这个两栖动物模型系统中学到的不依赖胚基的皮肤再生的知识可以更好地再生 哺乳动物的皮肤再生机制，其组织通常无需胚基即可愈合。