Project description:Foetal skin is known to heal without scar. This ability is lost in the third trimester of gestation. In mouse, scarless wound healing was reported until the day 15-16 of gestation. A range of factors that could explain the mechanisms of scarless skin wound healing have been identified, to mention reduced immune response, a greater proportion of collagen type III, hyaluronic acid and transforming growth factor beta isoform 3. The involvement of epigenetic changes, which are known to determine developmental processes, has not been examined in the context of scarless foetal skin healing so far. We performed the microarray analysis methylome and transcriptome of murine foetal dorsal skin at embryonic day 15 contrasted with those in later phases at embryonic days 18-19 as well as the in the adult mouse. The group of genes which show decreased methylation status in the foetal skin before the loss of ability to scarless healing between embryonic day 15 and 18 are enriched with transcriptional factors involved in embryonic morphogenesis, epithelium development, neuron differentiation, and synapse functions. The genes with increased methylation after the transition are associated with cell death and epithelial cell differentiation, inflammatory and wounding response and the degradation of hyaluronic acid. A substantial part of DNA methylation differences observed between embryonic day 15 and 18 were retained later at embryonic day 19 and in adults and remarkably correlated with gene expression changes. A major part of genes encoding the key factors responsible for cutaneous wound healing show significant changes in gene expression following the transition from scar free to normal healing. The results show that skin methylome and transcriptome undergoe extensive alterations following the loss of ability to scarless healing, while the functions associated with the changes imply their central role in skin wound repair.
Project description:Foetal skin is known to heal without scar. This ability is lost in the third trimester of gestation. In mouse, scarless wound healing was reported until the day 15-16 of gestation. A range of factors that could explain the mechanisms of scarless skin wound healing have been identified, to mention reduced immune response, a greater proportion of collagen type III, hyaluronic acid and transforming growth factor beta isoform 3. The involvement of epigenetic changes, which are known to determine developmental processes, has not been examined in the context of scarless foetal skin healing so far. We performed the microarray analysis methylome and transcriptome of murine foetal dorsal skin at embryonic day 15 contrasted with those in later phases at embryonic days 18-19 as well as the in the adult mouse. The group of genes which show decreased methylation status in the foetal skin before the loss of ability to scarless healing between embryonic day 15 and 18 are enriched with transcriptional factors involved in embryonic morphogenesis, epithelium development, neuron differentiation, and synapse functions. The genes with increased methylation after the transition are associated with cell death and epithelial cell differentiation, inflammatory and wounding response and the degradation of hyaluronic acid. A substantial part of DNA methylation differences observed between embryonic day 15 and 18 were retained later at embryonic day 19 and in adults and remarkably correlated with gene expression changes. A major part of genes encoding the key factors responsible for cutaneous wound healing show significant changes in gene expression following the transition from scar free to normal healing. The results show that skin methylome and transcriptome undergoe extensive alterations following the loss of ability to scarless healing, while the functions associated with the changes imply their central role in skin wound repair.
Project description:Impaired skin wound healing is a significant global health issue, especially among the elderly. Wound healing is a well-orchestrated process involving the sequential phases of inflammation, proliferation, and tissue remodeling. Although wound healing is a highly dynamic and energy-requiring process, the role of metabolism remains largely unexplored. By combining transcriptomics and metabolomics of human skin biopsy samples, we mapped the core bioenergetic and metabolic changes in normal acute as well as chronic wounds in elderly subjects. We found upregulation of glycolysis, the tricarboxylic acid cycle, glutaminolysis, and β-oxidation in the later stages of acute wound healing and in chronic wounds. To ascertain the role of these metabolic pathways on wound healing, we targeted each pathway in a wound healing assay as well as in a human skin explant model using metabolic inhibitors and stimulants. Enhancement or inhibition of glycolysis and, to a lesser extent, glutaminolysis had a far greater impact on wound healing than similar manipulations of oxidative phosphorylation and fatty acid β-oxidation. These findings increase the understanding of wound metabolism and identify glycolysis and glutaminolysis as potential targets for therapeutic intervention.
Project description:Mammals heal faster with imperfect fibrotic scars, while amphibians regenerate slower with scarless wound healing. These observations support the prevailing paradigm that speed of wound closure is inversely related to repair quality. Here we find evidence that this is a false trade-off. In multiple injury models, mice lacking CXCR2 (CXCR2-KO) globally improved both speed and quality of skin wound healing, including hair regeneration. We found CXCR2 primarily expressed in neutrophils, and injury induced neutrophils to secrete neutrophil extracellular traps (NETs). Mice engineered to be specifically deficient in myeloid CXCR2 or NET production partially recreated the phenotype with improved early speed of wound closure. Thus, CXCR2+ neutrophils regulate the speed of wound closure.
Project description:Proteinases play a pivotal role in wound healing by degrading molecular barriers, regulating cell-matrix interactions and availability of bioactive molecules. Matrix metalloproteinase-13 (MMP-13, collagenase-3) is a wide spectrum proteinase. Its expression and function is linked to the growth and invasion of many epithelial cancers such as squamous cell carcinoma. Moreover, the physiologic expression of MMP-13 is associated e.g. to scarless healing of human fetal skin and adult gingival wounds. While MMP-13 is not found in the normally healing skin wounds in human adults, it is expressed in mouse skin during wound healing. Thus, mouse wound healing models can be utilized for studying the role of MMP-13 in the events of wound healing. As the processes such as the migration and proliferation of keratinocytes, angiogenesis, inflammation and activation of fibroblasts are components of wound repair as well as of cancer, many results received from wound healing studies are also adaptable to cancer research. Classically, the process of wound healing can be devided into three phases which are histologically and functionally separate but temporally overlapping: 1) hemostasis and inflammation, 2) re-epithelialization and granulation tissue formation, and 3) matrix remodeling. Granulation tissue is formed into the wound via fibroplasia, angiogenesis and extracellular matrix (ECM) deposition by fibroblasts. Granulation tissue is rich in inflammatory cells, fibroblasts, myofibroblasts and blood vessels. After epidermal recovery, the granulation tissue is resolved via matrix remodeling and cell apoptosis. A sterile viscose cellulose sponge (VCS) characterized by defined size and structure can be used to experimentally induce formation of subcutaneous granulation tissue. Compared to normal granulation tissue, this model allows easy examination of the granulation tissue in its entirety but leaving out epidermal keratinocytes in the sample preparation. In this study, we studied the role of MMP-13 in the formation of mouse VCS-induced granulation tissue. We performed gene expression profiling of the granulation tissue samples of Mmp13-/- (KO) and wild type (WT) mice harvested at day 7, day 14 and day 21 after VCS implantation. Mmp13-/- (KO) mice were generated as described (Inada et al. 2004, PNAS, 101: 17192-17197) and used in these experiments after backcrossing at least seven generations into C57BL6 mice. The WT mice were generated from the backcrossed heterozygote Mmp13-/- (KO) mice. Granulation tissues were harvested at three time points (7d, 14d, 21d) from Mmp13-/- (KO) and WT mice. One sample of each mouse was analyzed (n=3, 7d; n=4, 14d; n=4, 21d; for each genotype). The samples were processed for RNA extraction and Affymetrix 3'IVT DNA microarray gene expression analysis.
Project description:When compared to skin, oral mucosal wounds heal rapidly and with reduced scar formation. This study used an Affymetrix microarray platform to compare the transcriptomes of oral mucosa and skin wounds in order to identify critical differences in the healing response at these two sites. Using microarrays, we explored the differences in gene expression in skin and oral mucosal wound healing in a murine model of paired equivalent-sized wounds. Samples were examined from day 0 to day 10 and spanned all stages of the wound healing process. Unwounded matched tissue was used as a control. Tissue samples collected at each post-wounding time point, as well as control samples, were represented by 3 biological replicates.