ABSTRACT: Defective fibroblast migration cause delayed wound healing (WH) and chronic skin lesions. Autologous micrograft (AMG) therapies have recently emerged as a new effective treatment able to improve wound healing capacity. However, the molecular mechanisms connecting their beneficial outcomes with the wound healing process are still unrevealed. Here, we show that AMG modulates primary fibroblast migration and accelerates skin re-epithelialization without affecting cell proliferation. We demonstrate that AMG is enriched in a pool of WH-associated growth factors that may provide the initiation signal for faster endogenous wound healing response. This, in turn leads to increased cell migration rate by elevating activity of ERK and subsequent activation of matrix metalloproteinase expression and their extracellular enzymatic activity. Moreover, AMG-treated wounds showed increased granulation tissue formation and organized collagen content. Overall, we shed light on AMG molecular mechanism supporting its potential to trigger highly improved wound healing process.
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: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.
Project description:Skin wound healing is one of the major prevalent medical problems in the worldwide. Wound healing involves multi-process synergy and re-epithelialization is an essential part of wound healing. Histone H3K36 tri-methylase Setd2 has been extensively studied in different biological processes and diseases. However, the function of Setd2 in the wound healing remains unclear. To elucidate the biological role of Setd2 in the skin wound healing, conditional gene targeting was employed to establish epidermis-specific Setd2-deficient mice. We found that Setd2 deficiency resulted in accelerated re-epithelialization during cutaneous wound healing by promoting keratinocytes proliferation and migration. Furthermore, we demonstrated that loss of Setd2 activated the AKT/mTOR pathway, and pharmacological inhibitions of AKT and mTOR with MK2206 and rapamycin delayed wound closure, respectively. In conclusion, our results reveal the essential role of Setd2 in skin wound healing that is Setd2 loss promotes cutaneous wound healing via activation of AKT/mTOR signaling.
Project description:Skin wound healing is one of the major prevalent medical problems in the worldwide. Wound healing involves multi-process synergy and re-epithelialization is an essential part of wound healing. Histone H3K36 tri-methylase Setd2 has been extensively studied in different biological processes and diseases. However, the function of Setd2 in the wound healing remains unclear. To elucidate the biological role of Setd2 in the skin wound healing, conditional gene targeting was employed to establish epidermis-specific Setd2-deficient mice. We found that Setd2 deficiency resulted in accelerated re-epithelialization during cutaneous wound healing by promoting keratinocytes proliferation and migration. Furthermore, we demonstrated that loss of Setd2 activated the AKT/mTOR pathway, and pharmacological inhibitions of AKT and mTOR with MK2206 and rapamycin delayed wound closure, respectively. In conclusion, our results reveal the essential role of Setd2 in skin wound healing that is Setd2 loss promotes cutaneous wound healing via activation of AKT/mTOR signaling.
Project description:Injuries to the skin can result in non-healing wounds, characterized by prolonged inflammation, failure to close, and chronic pain. Basal keratinocytes in the epidermis respond to signals activated following injury by proliferating, migrating, and differentiating to restore the epidermal barrier. The skin is densely innervated by peripheral sensory nerves, which contribute to the wound repair response. Although it is known that nerves are important for successful wound healing, the underlying cellular mechanisms of this phenomenon, and particularly the role of nerves in directing keratinocyte re-epithelialization, are poorly understood. To explore the relationship between sensory nerves and keratinocyte function in vitro, we cultured keratinocytes with conditioned media collected from dorsal root ganglia (DRG) in both homeostatic and post-wounding conditions and found that keratinocyte migration and proliferation, functions essential for re-epithelialization, were modulated by DRG conditioned media. Using a proteomic approach, we characterized the secretome of cultured DRG and identified key factors essential for wound healing, including extracellular matrix proteins, growth factors, and metabolic factors involved with ATP production, which was correlated with an increase in ATP rates of keratinocytes cultured in DRG conditioned medium. Our results advance our understanding of the microenvironmental cues that direct keratinocyte function during key events of cutaneous wound healing in vitro to drive the development of therapeutics that target dysregulated re-epithelialization in non-healing wounds.
Project description:Impaired re-epithelialization is a hallmark of non-healing, chronic skin wounds. These represent major causes of patient morbidity, particularly amongst ever-increasing ageing and diabetic populations, posing significant challenges to healthcare providers worldwide. Despite many treatment options being available, these often offer limited benefits to healing outcomes. We address the need for more efficacious treatments through evaluation of novel epoxy-tigliane compounds as chronic wound pharmaceuticals, based on their effectiveness in promoting keratinocyte healing responses and re-epithelialization in vivo. Here, we identify that prototype epoxy-tigliane (EBC-46) and analogue (EBC-211), accelerate G1/S and S/G2 cell cycle transitions and proliferation in a normal human keratinocyte cell line of skin origin (HaCaTs). EBC-46 and EBC-211 further induce HaCaT migration/wound repopulation, even with mitomycin C treatment, suggesting epoxy-tiglianes can promote migration/repopulation independently of proliferation. Epoxy-tiglianes modulate keratin, DNA synthesis/replication, cell cycle/proliferation, motility/migration, differentiation, proteinase; and cytokine/chemokine gene expression, to facilitate enhanced responses. Although epoxy-tiglianes down-regulate cytokine/chemokine agonists of keratinocyte proliferation/migration, we demonstrate that enhanced HaCaT responses are mediated through protein kinase C (PKC) phosphorylation and abrogated by inhibition of PKC activation with bisindolylmaleimide-1 (BIM-1). By identifying how epoxy-tiglianes stimulate keratinocyte healing responses, we highlight their potential as novel therapeutics for impaired re-epithelialization associated with non-healing, chronic wounds.
Project description:In order to clarify the human response of re-epithelialization, we biopsied split-thickness skin graft donor site wounds immediately before and after harvesting, as well as during the healing process 3 and 7 days thereafter. Altogether 25 biopsies from 8 patients qualified for the study. All samples were analysed by genome-wide microarrays. Here we identified the genes associated with normal skin re-epithelialization on time-scale, and organized them by similarities according to their induction or suppression patterns during wound healing. Overall 25 samples were analyzed
Project description:Proteases control complex tissue responses by modulating inflammation, cell proliferation and migration, and matrix remodeling. All these processes are orchestrated in cutaneous wound healing to restore the skin’s barrier function upon injury. Altered protease activity has been implicated in the pathogenesis of healing impairments, and proteases are important targets in diagnosis and therapy of this pathology. Global assessment of proteolysis at critical turning points after injury will define crucial events in acute healing that might be disturbed in healing disorders. As optimal biospecimens, wound exudates contain an ideal proteome to detect extracellular proteolytic events, are non-invasively accessible, and can be collected at multiple time points along the healing process from the same wound in the clinics. In this study, we applied multiplexed Terminal Amine Isotopic Labeling of Substrates (TAILS) to globally assess proteolysis in early phases of cutaneous wound healing. By quantitative analysis of proteins and protein N termini in wound fluids from a clinically relevant pig wound model, we identified more than 650 proteins and discerned major healing phases through distinctive abundance clustering of markers of inflammation, granulation tissue formation, and re-epithelialization. TAILS revealed a high degree of proteolysis at all time points after injury by detecting almost 1300 N-terminal peptides in ~450 proteins, most of which could not be assigned to known mature protein N termini. Quantitative positional proteomics mapped pivotal interdependent processing events in the blood coagulation cascade, detailed activating thrombin cleavages in vivo, and temporally discerned clotting and fibrinolysis during the healing process. Similarly, we found virtually all major cleavages in complement activation and inactivation and demonstrated time-dependent changes in the proteolytic potential of the wound milieu by detecting processing of complement C3 at distinct time points after wounding and by different proteases.
Project description:The present study aimed to investigate the role of Thbs4 in skin regeneration and elucidate its effects on cellular responses. Here we show that Thbs4 expression is upregulated in healing skin wounds and wound healing can be promoted by the application of recombinant Thbs4 protein. Thbs4 was shown to promote keratinocyte proliferation and fibroblast migration by activating β-catenin signalling cascade. This indicates that incorporating Thbs4 into novel wound healing therapies can be a promising therapeutic strategy for hard-to-heal chronic wounds.
Project description:Hypoxia is one of the factors that govern reparative vs regenerative skin wound healing. Data-independent acquisition (DIA) experiment was carried out to study the effect of hypoxia and Foxn1 on mice dermal fibroblast proteomics signature and skin wound healing of Foxn1-deficient (Foxn1-/-) mice.