Blastema-independent Mechanism for Regeneration in Salamanders

蝾螈的不依赖胚基的再生机制

• 批准号: 10553618
• 负责人: David M. Gardiner
• 金额: $ 17.27万
• 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 2024-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10553618
• 关键词: Adult; Ambystoma; Ambystoma mexicanum; Amphibia; BMP7 gene; Biological Assay; Biological Models; Biology; Bone Morphogenetic Proteins; 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; Learning; Ligands; Limb structure; Macrophage; Mammals; Mediating; Mesenchymal; Microscopy; Modeling; Molecular; Molecular Profiling; Multipotent Stem Cells; Natural regeneration; Nerve; Pathway interactions; Population; Process; Proteins; Repression; 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; blastema; candidate identification; cell type; confocal imaging; differential expression; gene repression; healing; innovation; insight; 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.

项目总结 虽然人类和其他哺乳动物的再生能力有限，但火蜥蜴，包括 墨西哥Ambystoma(Axolotl)具有高度的再生性，并提供了许多关于 器官修复的机制。在受伤时，紫杉醇会在伤口处产生“胚芽”组织，这些组织含有 参与再生修复的多能祖细胞，有助于多种新形成的细胞类型。 哺乳动物不能形成多能胚泡细胞通常被认为是实现真核细胞的关键障碍。 创面再生愈合。紫杉醇还可以再生皮肤，皮肤通常由一层表皮组成，两层- 层状真皮和许多分泌腺。与流行的观念相反，完整的组织 再生需要胚芽，我们现在证明了紫杉醇皮肤在没有胚芽的情况下再生，而且在 事实上，胚泡的形成抑制了腺体皮肤的再生。 这项应用将集中于定义一种新的细胞和信号转导机制，即胚泡非依赖性 火蜥蜴的皮肤再生。为了实现这一目标，该项目将利用 所谓的辅助肢体模型(ALM)-一种高度可处理的轴突创伤模型系统，可以 实验目标是：(I)快速再生没有胚泡的含腺皮肤，或(Ii)形成 胚芽出现神经偏斜时，皮肤再生明显延迟。使用 活体紫杉醇成像、谱系追踪、单细胞rna-seq、功能蛋白递送和基因 在ALM模型中的扰动分析，在我们的第一个目标中，我们将确定两栖动物皮肤腺是否再生 关键取决于表皮-真皮之间的相互作用，以及这些相互作用在胚泡形成过程中是否被阻止 伤口是由于它们的成纤维细胞未成熟所致。第二个目标是发现新的信号和表观遗传学 再生皮肤中腺体新生的机制。特别是，我们将确立 骨形态发生蛋白配体BMP7及其拮抗剂Gremlin和BMP7的抗衡作用 第二类组蛋白去乙酰基酶HDAC10在我们的RNA中的激活作用 SEQ研究--腺体再生和皮肤成纤维细胞谱系成熟。 基于大量的初步数据，研究的前提是强有力的。建议进行的研究包括 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，并将促进关于两栖动物皮肤细胞类型的知识。建议的研究具有创新性。 因为他们将建立一种新的不依赖胚泡的再生模式，并将识别新的皮肤 再生诱导表观遗传和信号因子。最终，我们希望能够将新的 从这种不依赖胚泡的两栖动物皮肤再生模型系统中学习到的知识更好地 了解哺乳动物的皮肤再生机制，哺乳动物的组织通常在没有胚芽的情况下愈合。