Project description:Hsa_circ_0084443 expression level is down-regulated during normal skin wound healing and higher level of hsa_circ_0084443 was found in chronic non-healing diabetic foot ulcers compared to normal wounds. However, the biological function of hsa_circ_0084443 in epidermal keratinocytes during wound repair has not been studied. To study the genes regulated by hsa_circ_0084443, we transfected siRNA targeting hsa_circ_0084443 diagnostic junction into human primary epidermal keratinocytes to knockdown hsa_circ_0084443 expression. We performed a global transcriptome analysis of keratinocytes upon knockdown of hsa_circ_0084443 using Affymetrix arrays.
Project description:Non-healing wounds are a major area of unmet clinical need that remain problematic to treat; therefore, improved understanding of pro-healing mechanisms is invaluable. The enzyme arginase1 is involved in pro-healing responses with its role in macrophages best-characterised. Arginase1 is also expressed by keratinocytes; however, the function of arginase1 in these critical wound repair cells is not understood. We characterised arginase1 expression in keratinocytes during normal cutaneous repair and reveal de novo temporal and spatial expression at the epidermal wound edge. Interestingly, epidermal arginase1 expression was decreased in both human and murine delayed healing wounds. We, therefore, generated a keratinocyte specific arginase1-null mouse model (K14-cre;Arg1fl/fl) to explore arginase function. Wound repair, linked to changes in keratinocyte proliferation, migration and differentiation, was significantly delayed in K14-cre;Arg1fl/flmice. Gene expression was studied by microarray.
Project description:Classic Ehlers Danlos syndrome (cEDS) is one of the most common genetic disorders of the connective tissue and musculoskeletal system characterized by mutations in genes encoding for type V collagen. Defects in wound healing constitute one of the most common and debilitating symptoms in individuals with cEDS but currently, no therapeutic strategies exist to attenuate wound healing defects in cEDS. We create a new murine model of cEDS, that remarkably phenocopies wound healing defects in human cEDS. Using this model, we show that an abnormal extracellular matrix (ECM) characterized by fibrillar disarray, altered mechanical properties and decreased collagen deposition contribute to the wound healing defect in cEDS. The cEDS animals exhibit decreased expression of epidermal genes and increased inflammation consistent with the human phenotype. We show that integrin expression is altered in wounds of cEDS animals and small molecule modulators of mechanosensitive integrin signaling attenuate wound healing defects. Finally, we demonstrate that rescuing extracellular matrix defects by injecting wild type fibroblasts into wounds of cEDS animals significantly enhances epidermal gene expression, decreases inflammation, augments wound closure and rescues defective wound repair. Taken together, these observations suggest that modulation of the extracellular matrix in Ehlers-Danlos syndrome either with small molecule inhibitors of mechanosensitive integrin signaling, or direct injection of wild type fibroblasts into the wound bed may have therapeutic potential for enhancing wound healing in cEDS.
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:The lncRNA LOC100130476 (named as WAKMAR2) was found to be down-regulated in epidermal keratinocytes in human chronic non-healing wounds compared to normal acute wounds and the intact skin. However, its biological role in keratinocytes during wound repair has not been studied. To study the genes regulated by WAKMAR2, we transfected Antisense LNA GapmeR against WAKMAR2 into human primary epidermal keratinocytes to deplete it. We performed a transcriptome-wide gene expression level profiling of keratinocytes upon depletion of WAKMAR2 using Affymetrix arrays.
Project description:While considerable progress has been made towards understanding the complex processes and pathways that regulate human wound healing, regenerative medicine has been unable to develop therapies that coax the natural wound environment to heal scar-free. The inability to induce perfect skin regeneration stems partly from our limited understanding of how scar-free healing occurs in a natural setting. Here we have investigated the wound repair process in adult axolotls and demonstrate that they are capable of perfectly repairing full thickness excisional wounds made on the flank. In the context of mammalian wound repair, our findings reveal a substantial reduction in hemostasis, reduced neutrophil infiltration and a relatively long delay in production of new extracellular matrix (ECM) during scar-free healing. Additionally, we test the hypothesis that metamorphosis leads to scarring and instead show that terrestrial axolotls also heal scar-free, albeit at a slower rate. Analysis of newly forming dermal ECM suggests that low levels of fibronectin and high levels of tenascin-C promote regeneration in lieu of scarring. Lastly, a genetic analysis during wound healing comparing epidermis between aquatic and terrestrial axolotls suggests that matrix metalloproteinases may regulate the fibrotic response. Our findings outline a blueprint to understand the cellular and molecular mechanisms coordinating scar-free healing that will be useful towards elucidating new regenerative therapies targeting fibrosis and wound repair. We used microarray analysis to determine the gene expression changes that take place during scar free wound healing in aquatic and terrestrial axolotl salamanders. Epidermal tissue was harvested using a 4mm biopsy punch. Two wounds were made along the flank and posterior to the forelimbs. Harvested epidermis was pooled for each animal. Four biological replicates were collected from uninjured epidermis (D0) and at 1, 3, and 7 days post injury.
Project description:Wound priming in epidermal Lrig1 stem cell progeny leads to a more efficient response to future injuries. To understand if primed progenitors maintain during aging the transcriptional program acquired during wound healing in young age, we performed single cell RNA-Seq of Lrig1 stem cell progeny 40 weeks after injury.
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.