A Regenerative Trait in Mice with a Point Mutation in TGFBR1
ABSTRACT: Regeneration of differentiated tissue in mammals is rare. In an effort to identify genes that affect the healing process, we screened G3 mice containing germline point mutations for closure of an ear punch wound. One particular line was identified with a heritable hole closure phenotype containing differentiated tissue. Mapping and sequencing efforts revealed that the mutant mice harbor a R244Q point mutation coded by the TGFBR1 gene which leads to enhanced signaling activity in a reporter gene assay. Although there was no obvious effect on the immune system, bone marrow stromal cells from the mutant mice revealed accelerated chondrogenesis, mimicking the in vivo development of cartilage islands in the regenerated ears. This genetically well-defined mouse model should help to further dissect the role of TGF-beta signaling in vertebrate healing and regeneration. Keywords: treatment and time course in wt and mutant samples Overall design: TGFb or vehicle treatment at different time points in mouse embryonic fibroblasts from wildtype and TGFb1 mutant (heterozygous and homozygous) mice. Mutant is constitutively active.
Project description:Regeneration of differentiated tissue in mammals is rare. In an effort to identify genes that affect the healing process, we screened G3 mice containing germline point mutations for closure of an ear punch wound. One particular line was identified with a heritable hole closure phenotype containing differentiated tissue. Mapping and sequencing efforts revealed that the mutant mice harbor a R244Q point mutation coded by the TGFBR1 gene which leads to enhanced signaling activity in a reporter gene assay. Although there was no obvious effect on the immune system, bone marrow stromal cells from the mutant mice revealed accelerated chondrogenesis, mimicking the in vivo development of cartilage islands in the regenerated ears. This genetically well-defined mouse model should help to further dissect the role of TGF-beta signaling in vertebrate healing and regeneration. Keywords: treatment and time course in wt and mutant samples TGFb or vehicle treatment at different time points in mouse embryonic fibroblasts from wildtype and TGFb1 mutant (heterozygous and homozygous) mice. Mutant is constitutively active.
Project description:The MRL/MpJ mouse strain is known as a model of mammalian regeneration. The strain exhibits an unusual capacity in regenerative wound healing manifested by scarless ear-hole closure and enhanced regeneration response reported in other organs. A significant feature of the strain is that the adult MRL/MpJ mouse retains several embryonic biochemical characteristics, including increased expression of stem cell markers. As the regenerative response after injury is rather limited in mammals the MRL/MpJ mouse is a great model to study the molecular and cellular basis of scarless wound healing. We report here the analysis of genome-wide transcriptomic profiles in the heart, ear, spleen, liver and bone marrow of the MRL/MpJ mouse. We used gene expression microarray, which interrogates 44.170 of mouse transcripts, in order to identify the genes exhibiting remarkable differences in expression in the MRL/MpJ mouse compared to two reference strains: C57BL/6J and BALB/c. The comparison revealed hundreds of differentially expressed transcripts. Significant enrichments of genes engaged in retinol metabolism, peroxisome proliferator-activated receptor (PPAR), wound healing, and homeobox pathways distinguishes the differentially expressed transcripts up-regulated in the MRL/MpJ mouse, whereas the genes related to immune response, including including response to wounding are greatly enriched among those down-regulated. The same functional categories were associated with remarkable parallels between the transcriptomic patterns in murine neonates and the adult MRL/MpJ mouse. Overall design: 15 samples, each sample is a poll representing three animals
Project description:Mice were wounded and skin samples of the scar collected on the day of wound closure. We compared Mixed mice (B6/FVB/SJL), a strain of high regeneration, versus C57bl mice, a strain of low regeneration. Whole skin biopsies of wound scars were submitted for Affymetrix Exon arrays. 4 mice each of 2 distinct strains of differing regeneration levels were collected.
Project description:Mice were wounded and measured for regeneration starting 4 days after wound closure with simultaneous measurement of hair follicle neogenesis and biopsing. At each time point, RNA was collected from one mouse with high number of regenerated follicles and one without regenerated follicles. Whole skin biopsies of wound scars were submitted for Affymetrix Exon arrays. 3 replicates of mice with high number of regenerated follicles, 3 replicates of mice with no regenerated follicles; each pair taken at a different date after wound closure.
Project description:MRL mice display unusual healing properties. When MRL ear pinnae are hole punched, the holes close completely without scarring, with re-growth of cartilage, and reappearance of both hair follicles and sebaceous glands. Studies using (MRL/lpr x C57BL/6)F2 and backcross mice first showed that this phenomenon was genetically determined and that multiple loci contributed to this quantitative trait. The lpr mutation itself, however, was not one of them. In the present study, we examined the genetic basis of healing in the Large (LG/J) mouse strain, a parent of the MRL mouse and a strain that shows the same healing phenotype. LG/J mice were crossed with Small (SM/J) mice and the F2 population was scored for healing and their genotypes determined at >200 polymorphic markers. As we previously observed for MRL and (MRL x B6) F2 mice, the wound healing phenotype was sexually dimorphic with female mice healing more quickly and more completely than male mice. We found quantitative trait loci (QTL) on chromosomes (chr) 9, 10, 11, and 15. The heal QTL on chrs 11 and 15 were linked to differential healing primarily in male animals, whereas QTL on chrs 9 and 10 were not sexually dimorphic. A comparison of loci identified in previous crosses with those in the present report using LG/J x SM/J showed that loci on chrs 9, 11 and 15 co-localized with those seen in previous MRL crosses, whereas the locus on chr 10 was not seen before and was is contributed by SM/J. Overall design: Illumina v6 arrays used for tissue from punched SM/J and LG/J ear holes. Triplicate samples were used for each strain and each timepoint.
Project description:Uninjured skin of adult C57BL/6J mice and mouse fetuses at 18 day of embryonic development (E18), as the models of reparative healing, and Nude and E14, as the models of regenerative healing, were characterized for their gene expression profiles by next-generation high-throughput DNA sequencing. The comparisons of gene expression profiles indicated that there were more similarities within each model of healing (Nude was more similar to E14 and B6 was more similar to E18). The analysis revealed that Nude and E14 showed in common the up-regulation of genes associated with tissue remodeling, cytoskeletal rearrangements, wound healing and immune response and the down-regulation of genes coupled to differentiation. Gene expression profiles of regenerative adult Nude mice display features of an attenuated skin development resembling that of E14 mice, thus the Nude mouse may be considered as a unique example of neoteny among mammals. The similar expression profiles of genes in the skin of both Nude and E14 mice are direct or indirect consequences of FOXN1 deficiency. FOXN1 appears to regulate the balance between cell proliferation and differentiation and its lack creates a pro-regenerative environment. Overall design: Skin (C57BL/6J, Nude, E14, E18) and epidermis (C57BL/6J, Nude) mRNA profile were generated by sequencing using the SOLiD™ 3 System.
Project description:Variability of regenerative potential among animals has long perplexed biologists. Based on their amazing regenerative abilities, planarians have become important models for understanding the molecular basis of regeneration; however, planarian species with limited regenerative abilities are also found. Despite the importance of understanding the differences between closely related, regenerating and non-regenerating organisms, few studies have focused on the evolutionary loss of regeneration, and the molecular mechanisms leading to such regenerative loss remain obscure. Here we examine Procotyla fluviatilis, a planarian with restricted ability to replace missing tissues, utilizing next-generation sequencing to define the gene expression programs active in regeneration-permissive and regeneration-deficient tissues. We found that Wnt signaling is aberrantly activated in regeneration-deficient tissues. Remarkably, down-regulation of canonical Wnt signaling in regeneration-deficient regions restores regenerative abilities: blastemas form and new heads regenerate in tissues that normally never regenerate. This work reveals that manipulating a single signaling pathway can reverse the evolutionary loss of regenerative potential. RNA-seq experiments to identify gene expression changes following amputation in body regions with variable regenerative potential. Adult Procotyla fluviatilis were amputated at sites either anterior or posterior to the pharynx. After 24 hours post-amputation, tissues near the amputation site were excised and RNA was extracted. Similar tissues were excised from uncut control animals. Samples were processed for RNA-seq using Illumina procedures. We generated a de novo P. fluviatilis transcriptome and used RNA sequencing (RNA-seq) to characterize transcripts from excised tissue fragments in Reg+ and Reg- body regions 24 hours post-amputation. We performed parallel analyses on tissues excised from intact animals at identical body regions to account for regional differences in transcripts, thereby identifying changes resulting from amputation. Samples A1-A3 = Regeneration-proficient (Reg+) tissue excision 24 hours after amputation. Samples B1-B3 = Tissue excision from regeneration-proficient (Reg+) region but not amputated. Samples C1-C3 = Tissue excision from regeneration-deficient (Reg-) tissues 24 hours after amputation. Samples D1, D3-D4 = Tissue excision from regeneration-deficient (Reg-) region that was not amputated.
Project description:Stem and progenitor cells are the critical units for tissue maintenance, regeneration, and repair. The activation of regenerative events in response to tissue injury has been correlated with mobilization of tissue-resident progenitor cells, which is functional to the wound healing process. However, until now there has been no evidence for the presence of cells with a healing capacity circulating in healthy conditions. We identified a rare cell population present in the peripheral blood of healthy mice that actively participates in tissue repair. These Circulating cells, with a Homing ability and involved in the Healing process (CH cells), were identified by an innovative flowcytometry strategy as small cells not expressing CD45 and lineage markers. Their transcriptome profile revealed that CH cells are unique and present a high expression of key pluripotency- and epiblast-associated genes. More importantly, CH-labeled cells derived from healthy Red Fluorescent Protein (RFP)-transgenic mice and systemically injected into syngeneic fractured wild-type mice migrated and engrafted in wounded tissues, ultimately differentiating into tissue-specific cells. Accordingly, the number of CH cells in the peripheral blood rapidly decreased following femoral fracture. These findings uncover the existence of constitutively circulating cells that may represent novel, accessible, and versatile effectors of therapeutic tissue regeneration. Analysis of murine circulating PlCH cells, two biological replicates
Project description:Whole Exome Sequencing of cohorts of Mutant Braf mouse model melanoma DNA and germline DNA. The cohorts are (1) Mutant Braf mouse model melanomas, (2) Mutant Braf mouse model melanomas from UVR exposed mice and (3) Mutant Braf mouse model melanomas from UVR exposed, sunscreen protected mice.
Project description:Temporomandibular joint degenerative disease (TMJ-DD) is a chronic form of TMJ disorder that specifically afflicts people over the age of 40 and targets women at a higher rate than men. Prevalence of TMJ-DD in this population suggests that estrogen loss plays a role in the disease pathogenesis. Thus, the goal of the present study was to determine the role of estrogen on chondrogenesis and homeostasis via estrogen receptor alpha (ERα) during growth and maturity of the joint. Young and mature WT and ERαKO female mice were subjected to ovariectomy procedures and then given placebo or estradiol treatment. The effect of estrogen via ERα on fibrocartilage morphology, matrix production, and protease activity was assessed. In the young mice, estrogen via ERα promoted mandibular condylar fibrocartilage chondrogenesis partly by inhibiting the canonical Wnt signaling pathway through upregulation of sclerostin (Sost). In the mature mice, protease activity was partly inhibited with estrogen treatment via the upregulation and activity of protease inhibitor 15 (Pi15) and alpha-2-macroglobulin (A2m). The results from this work provide a mechanistic understanding of estradiol on TMJ growth and homeostasis and can be utilized for development of therapeutic targets to promote regeneration and inhibit degeneration of the mandibular condylar fibrocartilage. Overall design: Examination and comparison of the role of 17β-estradiol (E2) via estrogen receptor alpha (Eralpha) on the transcriptional regulation of genes in the mandibular condylar fibrocartialge of skeletally immature (7-week old) female mice.