Project description:The order Caudata of amphibians has been important in the study of tissue regeneration. The most complete genetic available data from salamanders are from Ambystoma mexicanum (Ambystomidae) and Notophthalmus viridescens (Salamandridae). Transcriptome data obtained with Next-generation sequencing technology has become a useful tool to discover new candidate genes in non-model organisms without a genome of reference. This study highlights the need of performing RNA-sequencing in other salamander species to compare and identify important clusters of genes that could be modulating important biological process in amphibians. Here we describe a de novo reference transcriptome and its annotation of a non-model terrestrial salamander, Bolitoglossa vallecula (Caudata: Plethodontidae). For this purpose, we utilized genome protein databases from vertebrates, nucleotide sequences obtained for salamander species, and a de novo reference transcriptomes of Bolitoglossa ramosi to conduct a homology analysis. While the majority of the transcripts recovered homologs with Bolitoglossa ramosi, only a minority of the data (22%; n= 94,739) recovered homologs with other vertebrates. We also compared the transcriptome profile of skin tissue between these Bolitoglossa species. We found a group of antimicrobial peptides, such as cathelicidins, which have been not previously described in salamanders and could be important modulators of different biological process. All animals used in this work were collected under the Contract on Genetic Access for scientific research for non commercial profit (Contrato de acceso a recursos genéticos para la investigación científica sin interés commercial) to Resources number 118–2015.
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.
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:Restriction-site associated DNA sequences of Eurycea salamanders
Project description:The gut microbiota and tumor-associated macrophages (TAM) impact anti-PD-1 checkpoint blockade. Reprogramming TAM by either blocking or deleting the macrophage receptor TREM2 attenuates tumor growth, and lack of functional TREM2 enhances tumor elimination by anti-PD-1. Here, we found that anti-PD-1 combined with TREM2 deficiency induces proinflammatory programs in intestinal macrophages and a concomitant expansion of Ruminococcus gnavus (R. gnavus) in the gut microbiota. Gavage of wild-type mice with R. gnavus recapitulated enhancement of anti-PD-1-mediated tumor elimination occurring in the absence of TREM2. The intestinal proinflammatory environment coincided with expansion, increased circulation and migration of TNF-producing CD4+ T cells to the tumor bed. Thus, TREM2 remotely controls anti-PD-1 checkpoint blockade through modulation of the intestinal immune environment and microbiota, with R. gnavus emerging as a potential probiotic agent for increasing responsiveness to anti-PD-1.
Project description:Humans and their microbiota have coevolved a mutually beneficial relationship, with the human host providing a hospitable environment for the microbes, and the microbiota providing many benefits including nutritional benefits and protection from pathogen infection1. Maintaining this relationship requires careful immune balance to contain commensals within the lumen while limiting inflammatory anti-commensal responses1,2. A number of groups describe T cell antigen-specific recognition of intestinal microbes3,4. While the local environment shapes effector cell differentiation3–5 it is unclear how microbiota-specific T cells are educated in the thymus. Here we identify that early life intestinal colonization leads to trafficking of microbial antigens from the intestine to the thymus by intestinal dendritic cells (DCs) which then expand microbiota-specific T cells. Once in the periphery, microbiota-specific T cells have pathogenic potential, or can protect against related pathogens. In this way, the developing microbiota shapes and expands the thymic and peripheral T cell repertoire, allowing for enhanced recognition of intestinal microbes and pathogens.
2021-04-01 | GSE171279 | GEO
Project description:Fecal microbiota characterization Seychelles giant tortoises (Aldabrachelys gigantea) living in in wild and in controlled environment.