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.

项目摘要 虽然人类和其他哺乳动物的再生能力有限，但蝾螈，包括 墨西哥钝口螈（蝾螈）是高度再生的，并提供了许多见解， 器官修复机制。在受伤时，蝾螈在伤口部位产生“芽基”组织， 多能祖细胞参与再生愈合，有助于多种新形成的细胞类型。 哺乳动物不能形成多能芽基细胞通常被认为是真正的细胞分化的关键障碍。 再生伤口愈合蝾螈也可以再生皮肤，通常由表皮，两个- 真皮层以及许多分泌腺。与普遍认为完整的组织 再生需要芽基，我们现在表明，蝾螈皮肤再生没有芽基， 事实上，芽基的形成抑制了腺体皮肤的再生。 本申请将集中于定义一种新的细胞和信号机制， 蝾螈的皮肤再生为实现这一目标，本项目将利用 所谓的副肢模型（ALM）-蝾螈中高度易处理的伤口模型系统， 在实验上，本发明涉及：（i）快速再生无芽基的含腺体皮肤，或（ii）形成 芽基时，提出了一个偏离的神经，并显示显着延迟皮肤再生。使用 活蝾螈成像、谱系追踪、单细胞RNA-seq、功能蛋白递送和基因表达的组合 在ALM模型中的扰动分析，在我们的第一个目标中，我们将建立两栖动物皮肤腺再生 关键取决于表皮-真皮的相互作用，如果这些相互作用在胚泡形成中被阻止， 由于成纤维细胞的不成熟而导致的伤口。第二个目标是揭示新的信号传导和表观遗传 皮肤再生中腺体再生的机制。特别是，我们将确立 骨形态发生蛋白配体BMP 7及其拮抗剂GREMLIN和骨形成蛋白的平衡作用 II类组蛋白去乙酰化酶HDAC 10的激活作用-在我们的RNA中列出的最高差异表达基因- seq研究-关于腺体再生和皮肤成纤维细胞谱系成熟。 研究的前提是强有力的，基于大量的初步数据。拟议的研究是 重要的是，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，并将促进两栖动物皮肤细胞类型的知识。拟议的研究是创新的 因为它们将建立一种新的不依赖胚细胞的再生模式， 再生诱导表观遗传和信号传导因子。最终，我们希望能够将新的 从这种不依赖胚细胞的皮肤再生的两栖动物模型系统中学到的知识， 了解哺乳动物的皮肤再生机制，其组织通常在没有芽基的情况下愈合。