The essential role of connective-tissue cells during axolotl limb regeneration
Ontology highlight
ABSTRACT:
ORGANISM(S): Ambystoma mexicanum
PROVIDER: GSE294212 | GEO | 2025/04/16
REPOSITORIES: GEO
Similar Datasets
Project description:This experiment was performed to obtain an expression profiling of connective-tissue-derived cells at different time points during blastema formation after limb amputation. RNA extraction was performed from FACS sorted connective tissue cells from converted Prrx1Cre-ERT;CaggsSTOP/Cherry axolotls. 3 Biological replicates were obtained for each time point analyzed.
2025-04-17 | GSE294346 | GEO
Project description:Amputation of the axolotl forelimb results in the formation of a blastema, a transient tissue where progenitor cells accumulate prior to limb regeneration. Connective tissue (CT) – skeleton, periskeleton, tendon, dermis, interstitial cells – contributes the vast majority of cells that populate the blastema, however it is unclear how individual CT cells may reprogram their fate in order to rebuild the tetrapod limb. Here we use a combination of Cre-loxP reporter lineage tracking and single-cell (sc) RNA-seq to molecularly track, for the first time, adult CT cell heterogeneity and its transition to a limb blastema state. We uncover a multi-phasic molecular program where CT cell types found in the uninjured adult limb revert to a relatively homogenous progenitor state that participates in inflammation and extracellular matrix disassembly prior to proliferation, establishment of positional information, and ultimately re-differentiation. While the early regeneration transcriptome states are unique to the blastema, the later stages recapitulate embryonic limb development. Notably, we do not find evidence of a pre-existing blastema-like precursor nor limb bud-like progenitors in the uninjured adult tissue. However, we find that distinct CT subpopulations in the adult limb differentially contribute to proximal and distal portions of the regenerated limb. Together, our data illuminates molecular and cellular reprogramming during complex organ regeneration in a vertebrate.
2018-09-27 | GSE106269 | GEO
Project description:Study abstract: Axolotl salamanders (Ambystoma mexicanum) remain aquatic in their natural state, during which biomechanical forces on their diarthrodial limb joints are likely reduced relative to salamanders living on land. However, even as sexually mature adults, these amphibians can be induced to metamorphose into a weight-bearing terrestrial stage by environmental stress or the exogenous administration of thyroxine hormone. In some respects, this aquatic to terrestrial transition of axolotl salamanders through metamorphosis may model developmental and changing biomechanical skeletal forces in mammals during the prenatal to postnatal transition at birth and in the early postnatal period. To assess differences in the appendicular skeleton as a function of metamorphosis, anatomical and gene expression parameters were compared in skeletal tissues between aquatic and terrestrial axolotls that were the same age and genetically full siblings. The length of long bones and area of cuboidal bones in the appendicular skeleton, as well as the cellularity of cartilaginous and interzone tissues of femorotibial joints were generally higher in aquatic axolotls compared to their metamorphosed terrestrial siblings. A comparison of steady state mRNA transcripts encoding aggrecan core protein (ACAN), type II collagen (COL2A1), and growth and differentiation factor 5 (GDF5) in femorotibial cartilaginous and interzone tissues did not reveal any significant differences between aquatic and terrestrial axolotls. RNAseq samples: Total RNA was isolated from whole body tissue samples of Mexican axolotl salamanders (Ambystoma mexicanum) at the following developmental stages: Embryo at the tail bud stage, newly hatched larva, larva at the limb bud stage, juvenile at 8.5 centimeters, and adult using variations of guanidinium-based protocols. RNA quantity, purity, and integrity of both the individual samples and the resulting pool were determined with an Agilent 2100 Bioanalyzer using the Eukaryotic Total RNA nano series II analysis kit. The pooled RNA sample was poly-A selected and used for Illumina random priming directional library prep. Four lanes were sequenced only on one end providing single end reads and 4 lanes were sequenced at both ends giving paired-end reads. The library was sequenced on an Illumina HiSeq 2000 for 75bp reads producing 147,248,512 single end reads and 2 x 153,254,667 paired-end reads.
2018-07-29 | E-MTAB-6092 | biostudies-arrayexpress
Project description:Limb regeneration, while observed lifelong in salamanders, is restricted to pre-metamorphic stages in Xenopus laevis frogs. After amputation, post-metamorphic frogs form a blastema that grows only an unsegmented cartilage rod. Whether this loss is due to systemic factors such as the immune system or due to an intrinsic incapability of cells to form competent stem cells has been unclear. Here, we use genetic fate mapping to establish that, as in axolotl, connective tissue (CT) cells form the post-metamorphic frog blastema. Using heterochronic transplantation into the limb bud and single-cell transcriptomic profiling, we show that axolotl CT cells fully dedifferentiate and integrate to form lineages including cartilage in the developing limb. In contrast, frog blastema CT cells do not fully re-express the limb bud progenitor program, even when transplanted into the limb bud. Correspondingly, transplanted cells contribute to extraskeletal CT but not to developing cartilage. Further, using single-cell RNA-seq analysis we find that the embryonic and the adult frog cartilage differentiation programs are molecularly distinct. This work defines intrinsic restrictions in CT dedifferentiation as a limitation in adult regeneration.
2021-05-24 | GSE165901 | GEO
Project description:Amphibians such as the salamanders and the African clawed frog Xenopus are great models for regeneration studies because they can fully regenerate their lost organs. While axolotl can regenerate damaged organs throughout its lifetime, Xenopus has a limited regeneration capacity after metamorphosis. The ecotropic viral integrative factor 5 (Evi5), a cell-cycle-regulated protein that prevents cells from entering mitosis prematurely, is of great interest for it is highly upregulated in the limb blastema of axolotls, but its expression level remains unchanged in the fibroblastema of postmetamorphic frogs. Yet, its role in regeneration competent context in Xenopus has not been fully analyzed. Here we show that Evi5 is also upregulated in Xenopus tadpoles after limb and tail amputation, as it is in axolotls. Down-regulation of Evi5 with morpholino antisense oligos (Mo) impairs wound healing and blastema formation in limbs and tails in both axolotls and Xenopus tadpoles, suggesting a conserved function for Evi5 in regeneration. Using skin punch as a healing model we show that Evi5 is also involved in cell migration during wound healing. RNA-sequencing analysis shows that in addition to reduced signaling of Lepr, Pdgfa, Gdf5, evi5 Mo also downregulate lysine demethylases kdm6b and kdm7a, which are also required for limb regeneration. Thus, our results demonstrate that Evi5 plays a critical role in the regeneration of multiple systems in amphibians.
2022-11-24 | GSE218034 | GEO
Project description:The Mexican axolotl (Ambystoma mexicanum) is one member of a select group of vertebrate animals that has retained the amazing ability to regenerate multiple body parts. In addition to being an important model system for regeneration, the axolotl is also a leading model system for developmental biologists. Many genes used in development have been identified to be reused again during regeneration, however how this molecular circuitry is controlled during regeneration is unknown. In recent years microRNAs have been identified as key regulators of gene expression during development, in many diseases and also in regeneration. Here we have used deep sequencing combined with qRT-PCR to identify microRNAs that are involved in regulating regeneration in axolotl. This approach has enabled us to identify well known families of microRNAs and in addition to identify putative novel microRNAs that differentially regulated in the regenerating tissue. These findings suggest that microRNAs may play key roles in managing the spatial and temporal expression of genes important for ensuring that the correct tissues are regenerated. small RNA Sequencing (2 samples) in Ambystoma Mexicanum
2015-09-11 | E-GEOD-72057 | biostudies-arrayexpress
Project description:Transcriptome studies are revealing the complex gene expression basis of limb regeneration in the primary salamander model – Ambystoma mexicanum (axolotl). To better understand this complexity, there is need to extend analyses to additional salamander species. Using microarray and RNA-Seq, we performed a comparative transcriptomic study using A. mexicanum and two other ambystomatid salamanders: A. andersoni, and A. maculatum. Salamanders were administered forelimb amputations and RNA was isolated and analyzed to identify 405 non-redundant genes that were commonly, differentially expressed 24 hours post amputation. Many of the upregulated genes are predicted to function in wound healing and developmental processes, while many of the downregulated genes are typically expressed in muscle. The conserved transcriptional changes identified in this study provide a high-confidence dataset for identifying factors that simultaneous orchestrate wound healing and regeneration processes in response to injury, and more generally for identifying genes that are essential for salamander limb regeneration.
2018-07-04 | GSE116615 | GEO
Project description:Transcriptome studies are revealing the complex gene expression basis of limb regeneration in the primary salamander model – Ambystoma mexicanum (axolotl). To better understand this complexity, there is need to extend analyses to additional salamander species. Using microarray and RNA-Seq, we performed a comparative transcriptomic study using A. mexicanum and two other ambystomatid salamanders: A. andersoni, and A. maculatum. Salamanders were administered forelimb amputations and RNA was isolated and analyzed to identify 405 non-redundant genes that were commonly, differentially expressed 24 hours post amputation. Many of the upregulated genes are predicted to function in wound healing and developmental processes, while many of the downregulated genes are typically expressed in muscle. The conserved transcriptional changes identified in this study provide a high-confidence dataset for identifying factors that simultaneous orchestrate wound healing and regeneration processes in response to injury, and more generally for identifying genes that are essential for salamander limb regeneration.
2018-07-10 | GSE116777 | GEO
Project description:10X sequencing of immune cells and limb regeneratesImmune cells are known to be critical for successful limb regeneration in the axolotl (Ambystoma mexicanum), but many details regarding their identity, behavior, and function are yet to be resolved. We isolated peripheral leukocytes from the blood of adult axolotls and then created two samples for single-cell sequencing: 1) peripheral leukocytes (N = 7,889) and 2) peripheral leukocytes with presumptive macrophages from the intraperitoneal cavity (N = 4,998). Using k-means clustering, we identified 6 cell populations from each sample that presented gene expression patterns indicative of erythrocyte, thrombocyte, neutrophil, B-cell, T-cell, and myeloid cell populations. A seventh, presumptive macrophage cell population was identified uniquely from sample 2. We then isolated cells from amputated axolotl limbs at 1 and 6 days post-amputation (DPA) and performed single cell sequencing (N = 8,272 and 9,906 cells respectively) to identify immune and non-immune cell populations. Using k-means clustering, we identified 8 cell populations overall, with the majority of cells expressing erythrocyte specific genes. Even though erythrocytes predominated, we used an unbiased approach to identify infiltrating neutrophil, macrophage, and lymphocyte populations at both time points. Additionally, populations expressing genes for epidermal cells, fibroblast-like cells, and endothelial cells were also identified. Consistent with results from previous experimental studies, neutrophils were more abundant at 1 DPA than 6 DPA, while macrophages and non-immune cells exhibited inverse abundance patterns. Of note, we identified a small population of fibroblast-like cells at 1 DPA that was represented by considerably more cells at 6 DPA. We hypothesize that these are early progenitor cells that give rise to the blastema. The enriched gene sets from our work will aid future single-cell investigations of immune cell diversity and function during axolotl limb regeneration.
2020-07-07 | GSE136546 | GEO
Project description:The axolotl (<i>Ambystoma mexicanum</i>) is a caudate amphibian, which has an extraordinary ability to restore a wide variety of damaged structures by a process denominated epimorphosis. While the origin and potentiality of progenitor cells that take part during epimorphic regeneration are known to some extent, the metabolic changes experienced and their associated implications, remain unexplored. However, a circuit with a potential role as a modulator of cellular metabolism along regeneration is that formed by Lin28/let-7. In this study, we report two Lin28 paralogs and eight mature let-7 microRNAs encoded in the axolotl genome. Particularly, in the proliferative blastema stage amxLin28B is more abundant in the nuclei of blastemal cells, while the microRNAs amx-let-7c and amx-let-7a are most downregulated. Functional inhibition of Lin28 factors increase the levels of most mature let-7 microRNAs, consistent with an increment of intermediary metabolites of the Krebs cycle, and phenotypic alterations in the outgrowth of the blastema. In summary, we describe the primary components of the Lin28/let-7 circuit and their function during axolotl regeneration, acting upstream of metabolic reprogramming events.
2021-11-04 | MTBLS1708 | MetaboLights