NO production of granulocytes associated with antibacterial immune response in Tegillarca granosa.

Nitric oxide (NO) is a signaling molecule and immune effector produced by the nitric oxide synthases (NOS), which involved to various physiological processes of animals. In marine bivalves, hemocytes play important roles in antimicrobial innate immune response. Although hemocyte-derived NO has been detected in several bivalves, the immune function of hemocyte-derived NO is not well understood. Here, we investigated the antibacterial response of hemocyte-derived NO in the blood clam Tegillarca granosa. Two types of hemocytes including erythrocytes and granulocytes were isolated by Percoll density gradient centrifugation, their NO production and TgNOS expression level were analyzed. The results showed that NO was mainly produced in granulocytes and almost no detected in erythrocytes. The granulocytes showed significantly higher NO level and TgNOS expression level than the erythrocytes. And the TgNOS expression level was significantly increased in granulocytes after Vibro parahemolyticus challenge. In addition, the NO donor sodium nitroprusside (SNP) significantly increased the NO production of hemocytes to kill pathogenic bacteria. In summary, the results revealed that granulocytes-derived NO play vital roles in the antimicrobial immune response of the blood clam.

Single-cell profiling reveals transcriptomic signatures of vascular endothelial cells in non-healing diabetic foot ulcers.

Background: The treatment of diabetic foot ulcers (DFUs) poses a challenging medical problem that has long plagued individuals with diabetes. Clinically, wounds that fail to heal for more than 12 weeks after the formation of DFUs are referred to as non-healing/chronic wounds. Among various factors contributing to the non-healing of DFUs, the impairment of skin microvascular endothelial cell function caused by high glucose plays a crucial role. Our study aimed to reveal the transcriptomic signatures of non-healing DFUs endothelial cells, providing novel intervention targets for treatment strategies. Methods: Based on the GEO dataset (GSE165816), we selected DFU-Healer, DFU-Non-healer, and healthy non-diabetic controls as research subjects. Single-cell RNA transcriptomic sequencing technology was employed to analyze the heterogeneity of endothelial cells in different skin tissue samples and identify healing-related endothelial cell subpopulations. Immunofluorescence was applied to validate the sequencing results on clinical specimens. Results: The number of endothelial cells and vascular density showed no significant differences among the three groups of skin specimens. However, endothelial cells from non-healing DFUs exhibited apparent inhibition of angiogenesis, inflammation, and immune-related signaling pathways. The expression of CCND1, ENO1, HIF1α, and SERPINE1 was significantly downregulated at the transcriptomic and histological levels. Further analysis demonstrated that healing-related endothelial cell subpopulations in non-healing DFUs has limited connection with other cell types and weaker differentiation ability. Conclusion: At the single-cell level, we uncovered the molecular and functional specificity of endothelial cells in non-healing DFUs and highlighted the importance of endothelial cell immune-mediated capability in angiogenesis and wound healing. This provides new insights for the treatment of DFUs.

Mechanical pressure-induced dedifferentiation of myofibroblasts inhibits scarring via SMYD3/ITGBL1 signaling.

Pressure therapy (PT) is an effective intervention for reducing scarring, but its underlying mechanism remains largely unclear. Here, we demonstrate that human scar-derived myofibroblasts dedifferentiate into normal fibroblasts in response to PT, and we identify how SMYD3/ITGBL1 contributes to the nuclear relay of mechanical signals. In clinical specimens, reductions in SMYD3 and ITGBL1 expression levels are strongly associated with the anti-scarring effects of PT. The integrin ß1/ILK pathway is inhibited in scar-derived myofibroblasts upon PT, leading to decreased TCF-4 and subsequently to reductions in SMYD3 expression, which reduces the levels of H3K4 trimethylation (H3K4me3) and further suppresses ITGBL1 expression, resulting the dedifferentiation of myofibroblasts into fibroblasts. In animal models, blocking SMYD3 expression results in reductions of scarring, mimicking the positive effects of PT. Our results show that SMYD3 and ITGBL1 act as sensors and mediators of mechanical pressure to inhibit the progression of fibrogenesis and provide therapeutic targets for fibrotic diseases.

Bio-functional hydrogel with antibacterial and anti-inflammatory dual properties to combat with burn wound infection.

Burn infection delays wound healing and increases the burn patient mortality. Consequently, a new dressing with antibacterial and anti-inflammatory dual properties is urgently required for wound healing. In this study, we propose a combination of methacrylate gelatin (GelMA) hydrogel system with silver nanoparticles embed in γ-cyclodextrin metal-organic frameworks (Ag@MOF) and hyaluronic acid-epigallocatechin gallate (HA-E) for the burn wound infection treatment. Ag@MOF is used as an antibacterial agent and epigallocatechin gallate (EGCG) has exhibited biological properties of anti-inflammation and antibacterial. The GelMA/HA-E/Ag@MOF hydrogel enjoys suitable physical properties and sustained release of Ag+. Meanwhile, the hydrogel has excellent biocompatibility and could promote macrophage polarization from M1 to M2. In vivo wound healing evaluations further demonstrate that the GelMA/HA-E/Ag@MOF hydrogel reduces the number of the bacterium efficiently, accelerates wound healing, promotes early angiogenesis, and regulates immune reaction. A further evaluation indicates that the noncanonical Wnt signal pathway is significantly activated in the GelMA/HA-E/Ag@MOF hydrogel treated group. In conclusion, the GelMA/HA-E/Ag@MOF hydrogel could serve as a promising multifunctional dressing for the burn wound healing.

Identification of Potential Drug Therapy for Dermatofibrosarcoma Protuberans with Bioinformatics and Deep Learning Technology.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a rare mesenchymal tumor that is primarily treated with surgery. Targeted therapy is a promising approach to help reduce the high rate of recurrence. This study aims to identify the potential target genes and explore the candidate drugs acting on them effectively with computational methods. METHODS: Identification of genes associated with DFSP was conducted using the text mining tool pubmed2ensembl. Further gene screening was carried out by conducting Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Protein-Protein Interaction (PPI) network was constructed by using the Search Tools for the Retrieval of Interacting (STRING) database and visualized in Cytoscape. The gene candidates were identified after a literature review. Drugs targeting these genes were selected from Pharmaprojects. The binding affinity scores of Drug-Target Interaction (DTI) were predicted by a deep learning algorithm Deep Purpose. RESULTS: A total of 121 genes were found to be associated with DFSP by text mining. The top 3 statistically functionally enriched pathways of GO and KEGG analysis included 36 genes, and 18 hub genes were further screened out by constructing a PPI networking and literature retrieval. A total of 42 candidate drugs targeted at hub genes were found by Pharmaprojects under our restrictions. Finally, 10 drugs with top affinity scores were predicted by DeepPurpose, including 3 platelet-derived growth factor receptor beta kinase (PDGFRB) inhibitors, 2 platelet-derived growth factor receptor alpha kinase (PDGFRA) inhibitors, 2 Erb-B2 receptor tyrosine kinase 2 (ErbB-2) inhibitors, 1 tumor protein p53 (TP53) stimulant, 1 vascular endothelial growth factor receptor (VEGFR) antagonist, and 1 prostaglandin-endoperoxide synthase 2 (PTGS2) inhibitor. CONCLUSION: Text mining and bioinformatics are useful methods for gene identification in drug discovery. DeepPurpose is an efficient and operative deep learning tool for predicting the DTI and selecting the drug candidates.

Gene Identification and Potential Drug Therapy for Drug-Resistant Melanoma with Bioinformatics and Deep Learning Technology.

Background: Melanomas are skin malignant tumors that arise from melanocytes which are primarily treated with surgery, chemotherapy, targeted therapy, immunotherapy, radiation therapy, etc. Targeted therapy is a promising approach to treating advanced melanomas, but resistance always occurs. This study is aimed at identifying the potential target genes and candidate drugs for drug-resistant melanoma effectively with computational methods. Methods: Identification of genes associated with drug-resistant melanomas was conducted using the text mining tool pubmed2ensembl. Further gene screening was carried out by GO and KEGG pathway enrichment analyses. The PPI network was constructed using STRING database and Cytoscape. GEPIA was used to perform the survival analysis and conduct the Kaplan-Meier curve. Drugs targeted at these genes were selected in Pharmaprojects. The binding affinity scores of drug-target interactions were predicted by DeepPurpose. Results: A total of 433 genes were found associated with drug-resistant melanomas by text mining. The most statistically differential functional enriched pathways of GO and KEGG analyses contained 348 genes, and 27 hub genes were further screened out by MCODE in Cytoscape. Six genes were identified with statistical differences after survival analysis and literature review. 16 candidate drugs targeted at hub genes were found by Pharmaprojects under our restrictions. Finally, 11 ERBB2-targeted drugs with top affinity scores were predicted by DeepPurpose, including 10 ERBB2 kinase inhibitors and 1 antibody-drug conjugate. Conclusion: Text mining and bioinformatics are valuable methods for gene identification in drug discovery. DeepPurpose is an efficient and operative deep learning tool for predicting the DTI and selecting the candidate drugs.

Global Trends of Stem Cell Precision Medicine Research (2018-2022): A Bibliometric Analysis.

Background: Stem cells are a group of cells that can self-renew and have multiple differentiation capabilities. Shinya Yamanaka first discovered a method to convert somatic cells into pluripotent stem cells in 2006. Stem cell therapy can be summarized into three aspects (regenerative treatment, therapy targeted at stem cells, and establishment of disease models). Disease models are mainly established by induced pluripotent stem cells, and the research of stem cell precision medicine has been promising in recent years. Based on the construction of 3D, patient-specific disease models from pluripotent induced stem cells, proper research on disease development and treatment prognosis can be realized. Bibliometric analysis is an efficient way to quickly understand global trends and hotspots in this field. Methods: A literature search of stem cell precision medicine research from 2018 to 2022 was carried out using the Web of Science Core Collection.VOSviewer, R-bibliometrix, and CiteSpace software programs were employed to perform the bibliometric analysis. Results: A total of 552 publications were retrieved from 2018 to 2022. Annual publication outputs trended upward and reached a peak of 172 in 2021. The United States contributed the most publications (160, 29.0%) to the field, followed by China (63, 11.4%) and Italy (60, 10.9%). International academic collaborations were active. CANCERS was considered the most productive journal with 18 documents. NATURE was the most co-cited journal with 1860 times citations. The most cited document was entitled "Induced Pluripotent Stem Cells for Cardiovascular Disease Modeling and Precision Medicine: A Scientific Statement From the American Heart Association" with 9 times local citations. " precision medicine" (n = 89, 12.64%), "personalized medicine" (n = 72, 10.23%), "stem cells" (n = 43, 4.40%), and "induced pluripotent stem cells" (n = 41, 5.82%), "cancer stem cells" (n = 31, 4%), "organoids" (n = 26, 3.69%) were the top 6 frequent keywords. Conclusion: The present study performs a comprehensive investigation concerning stem cell precision medicine (2018-2022) for the first time. This research field is developing, and a deeper exploration of 3D patient-specific organoid disease models is worth more research in the future.

Vacuum-Assisted Closure and Skin Grafting Combined with Amphotericin B for Successful Treatment of an Immunocompromised Patient with Cutaneous Mucormycosis Caused by Mucor irregularis: A Case Report and Literature Review.

Cutaneous mucormycosis caused by Mucor irregularis (M. irregularis) is a rare condition that typically occurs in immunocompetent patients. Herein, we describe an immunocompromised patient with cutaneous M. irregularis infection who was successfully treated with debridement combined with vacuum assisted closure (VAC) negative pressure technique and split-thickness skin grafting. We present this case owing to its complexity and rarity and the successful treatment with surgical therapy. A 58-year-old man presented to our hospital with a history of skin ulcers and eschar on the right lower leg since two months. He had been receiving methylprednisolone therapy for bullous pemphigoid that occurred five months prior to the present lesions. Histopathological examination of a right leg lesion showed broad, branching hyphae in the dermis. Fungal culture and subsequent molecular cytogenetic analysis identified the pathogen as M. irregularis. After admission, methylprednisolone was gradually tapered and systemic treatment with amphotericin B (total dose 615 mg) initiated along with others supportive therapies. However, the ulcers showed no improvement, and amphotericin B had to be discontinued owing to development of renal dysfunction. After extensive surgical debridement combined with VAC and skin grafting, his skin ulcers were healed; subsequent fungal cultures of the lesions were negative. The patient exhibited no signs of recurrence at 36-month follow-up. Twenty-six cases with M. irregularis-associated cutaneous mucormycosis in literature were reviewed.

Transient High Glucose Causes Persistent Vascular Dysfunction and Delayed Wound Healing by the DNMT1-Mediated Ang-1/NF-κB Pathway.

The progression of diabetic complications does not halt despite the termination of hyperglycemia, suggesting a metabolic memory phenomenon. However, whether metabolic memory exists in and affects the healing of diabetic wounds, as well as the underlying molecular mechanisms, remain unclear. In this study, we found that wound healing was delayed, and angiogenesis was decreased in mice with diabetes despite the normalization of glycemic control. Thus, we hypothesized that transient hyperglycemic spikes may be a risk factor for diabetic wound healing. We showed that transient hyperglycemia caused persistent damage to the vascular endothelium. Transient hyperglycemia directly upregulated DNMT1 expression, leading to the hypermethylation of Ang-1 and reduced Ang-1 expression, which in turn induced long-lasting activation of NF-κB and subsequent endothelial dysfunction. An in vivo study further showed that inhibition of DNMT1 promoted angiogenesis and accelerated diabetic wound healing by regulating the Ang-1/NF-κB signaling pathway. These results highlight the dramatic and long-lasting effects of transient hyperglycemic spikes on wound healing and suggest that DNMT1 is a target for diabetic vascular complications.

Involvement of miRNA203 in the proliferation of epidermal stem cells during the process of DM chronic wound healing through Wnt signal pathways.

BACKGROUND: The biological role of miR-203 and the underlying mechanisms on the proliferation of epidermal stem cells (ESCs) have not yet been reported during the progression of chronic wound healing in diabetes mellitus. Our previous studies have observed that the expression of miR-203 showed a marked upregulation and ESC proliferation capacity was impaired in diabetes mellitus skin wounds in rats. METHODS: Wound models were established in normal rats and rats with type 2 diabetes. Expression level of miR-203 and the alteration of ESCs' number and function were detected. ESCs were isolated from the back skin of fetal rats to assess the effects of glucose in vitro. An antagomir to miR-203 was used to assess its effect on ESCs. Using microarray analysis, we further identified potential target genes and signaling pathways of miR-203. RESULTS: We found that high glucose significantly upregulated the expression of miR-203 and subsequently reduced the number of ESCs and impaired their proliferation capacity. Meanwhile, over-expression of miR-203 reduced the ESCs' numbers and impaired the proliferation capacity via downregulation of the Notch and Wnt signaling pathways. Conversely, inhibition of miR-203 enhanced the proliferation capacity. Additionally, silencing miR-203 in skin of rats with type 2 diabetes accelerated wound healing and improved healing quality via the upregulation of the Notch and Wnt signaling pathways. Finally, over-expression of miR-203 downregulated genes ROCK2, MAPK8, MAPK9, and PRKCA. CONCLUSION: Our findings demonstrated that induced expression of miR-203 by high glucose in type 2 diabetic rats decreased the number of ESCs and impaired ESC proliferation capacity via downregulating genes related to Notch and Wnt signaling pathways, resulting in a delayed wound healing.

Reduced hydration-induced decreased caveolin-1 expression causes epithelial-to-mesenchymal transition.

The reduced hydration environment induced by disruption of epithelial barrier function after injury results in excessive scarring, but the underlying mechanisms are poorly understood. We demonstrated that exposing keratinocytes to a reduced hydration environment causes epithelial-to-mesenchymal transition (EMT) and induces caveolin-1-dependent downregulation of E-cadherin. Reduced caveolin-1 expression and increased Snail expression are associated with low expression levels of E-cadherin. Caveolin-1 downregulation increases the transcriptional activity of ß-catenin-TCF/LEF-1, and overexpression of caveolin-1 inhibits EMT that results from reduced hydration. Our findings suggest a role for caveolin-1 downregulation in linking aberrant EMT to the reduced hydration environment: findings that may lead to new developments in the prevention and treatment of hypertrophic scar.

Prevascularized mesenchymal stem cell-sheets increase survival of random skin flaps in a nude mouse model.

A random skin flap is commonly applied in plastic and reconstructive surgery. The distal part of the random skin flap often risks necrosis because the blood flow may be compromised. Prevascularization is a widely used technology to intensify the vascularization function of biomaterials. In fact, human mesenchymal stem cell (hMSC) sheets promote neoangiogenesis. We speculated that prevascularized hMSC cell sheets (PHCS) would further improve neovascularization by producing more angiogenic growth factors in a random skin flap animal model. In this study, PHCS were set up by co-culturing human umbilical vein endothelial cells (HUVECs) with hMSC cell sheets (HCS). In vitro, we observed microvessel formation and significantly increased production of angiogenesis-related factors. Thus, we analyzed the microvessel networks, vascular maturation, and angiogenic growth factors of the cell sheet. In vivo, PHCS and HCS were implanted in a murine ischemic random skin flap model. Implanted PHCS significantly increased blood perfusion and improved skin flap survival when compared to untreated control skin flaps. The survival rate of the prevascularized and control skin flaps was assessed after 3, 5, and 7 days via analysis of macroscopic images and Laser Doppler Perfusion Imaging (LDPI). Additionally, the numbers of skin appendages, collagen fibers deposition, and epidermal thickness were evaluated. Moreover, the PHCS group also induced the most intense neovascularization, the upshot of which was a robust blood microcirculation supporting skin flap survival. Therefore, PHCS implantation can effectively enhance local neoangiogenesis and hence increase the survival of otherwise ischemic skin flaps. Hence, local administration of PHCS may serve as an alternative approach in improving random skin flap survival.

microRNA-203 Modulates Wound Healing and Scar Formation via Suppressing Hes1 Expression in Epidermal Stem Cells.

BACKGROUND/AIMS: Little is known how miR-203 is involved in epidermal stem cells (ESCs) differentiation and scar formation. METHODS: We first used luciferase assay to determine the interaction of miR-203 with the 3'-UTR in regulation of Hes1 expression. We then used flow cytometry to analyze the effects of miR-203 expression on the differentiation of ESCs to MFB by determination of CK15 ratio and α-SMA. To confirm the results of flow cytometry analysis, we used Western blot to examine the expression of α-SMA, Collagen I (Col I), and Collagen III (Col III), as well as the expression of Notch1, Jagged1, and Hes1 in ESCs after the treatment of pre-miR-203 or anti-miR-203. Finally, we examined the effects local anti-miR-203 treatment on would closure and scar formation using a mouse skin wound model. RESULTS: Pre-miR-203 treatment increased ESCs differentiation to MFB cells, as indicated by decreased CK15 ratio and increased MFB biomarkers. This phenomenon was reversed by overexpression of Hes1 in ESCs. In addition, skin incision increased expression of miR-203 in wound tissue. Local treatment of anti-miR-203 could accelerate wound closure and reduce scar formation in vivo, which was associated with increased re-epithelialization, skin attachment regeneration, and collagen reassignment. Finally, we confirmed that anti-miR-203 treatment could inhibit ESCs differentiation in vivo via increasing Hesl expression. CONCLUSION: Taken together, our results suggested that overexpression of miR-203 in ESCs after skin wound may be a critical mechanism underlying the scar formation.

Epidermal HMGB1 Activates Dermal Fibroblasts and Causes Hypertrophic Scar Formation in Reduced Hydration.

HMGB1 protein is a multifunctional cytokine involved in inflammatory reactions and is known to play a key role in tissue repair and fibrosis. However, the function of HMGB1 in fibrotic skin diseases, such as hypertrophic scar formation, remains unclear. In this study, HMGB1 was detected in the nuclei of epidermal cells in normal skin and had accumulated in the cytoplasm in hypertrophic scars. By establishing a keratinocyte-fibroblast co-culture and conditional medium treatment models, we found that a reduced hydration condition increased the expression and secretion of HMGB1 in keratinocytes, subsequently activating dermal fibroblasts. HMGB1 secreted from keratinocytes activated fibroblasts by promoting the nuclear import of MRTF-A, increased the nuclear accumulation of MRTF-A/SRF complexes and consequently enhanced α-smooth muscle actin promoter activation. Moreover, blockade of advanced glycation end products or Toll-like receptor 2/4 inhibited the fibroblast activation induced by HMGB1. Finally, local delivery of HMGB1 resulted in marked hypertrophic scar formation in rabbit hypertrophic scar models, while HMGB1 blockade exerted a clear anti-scarring effect. Our results indicate that high HMGB1 levels induced by a reduced hydration status play an important role in hypertrophic scar formation, strongly suggesting that HMGB1 is a novel target for preventing scarring.

Negatively-charged aerosol improves burn wound healing by promoting eNOS-dependent angiogenesis.

Aerosols exist in the form of liquid or solid particles that stably suspending in air. Our previous studies have found that aerosol can accelerate chronic wound healing. However, the biological effects of aerosol in burn wound healing and the underlying molecular mechanism remain unclear. This study aimed to investigate the effects of aerosol on the healing of deep partial-thickness burn wounds and its regulatory mechanisms. By employing a self-controlled model of rats, we demonstrated that aerosol treatment not only increased the healing rate, but also improved the healing quality of deep partial-thickness burn wounds. Besides, the excessive inflammatory responses in the burn wounds were inhibited, and the angiogenesis was increased after aerosol treatment. It did so by upregulating the expression of eNOS/NO, as well as the VGEF expression during the wound healing process. Our results demonstrate that the function of aerosol in promoting burn wound healing is achieved by activating eNOS/NO pathway.

Basic fibroblast growth factor reduces scar by inhibiting the differentiation of epidermal stem cells to myofibroblasts via the Notch1/Jagged1 pathway.

BACKGROUND: Basic fibroblast growth factor (bFGF) plays an important role in promoting wound healing and reducing scar, but the possible molecular mechanisms are still unclear. Our previous studies have found that activating the Notch1/Jagged1 pathway can inhibit the differentiation of epidermal stem cells (ESCs) to myofibroblasts (MFB). Herein, we document that bFGF reduces scar by inhibiting the differentiation of ESCs to MFB via activating the Notch1/Jagged1 pathway. METHODS: In in-vitro study, ESCs were isolated from 10 neonatal SD rats (1-3 days old), cultured in keratinocyte serum-free medium, and divided into six groups: bFGF group, bFGF + SU5402 group, bFGF + DAPT group, siJagged1 group, bFGF + siJagged1 group, and control group. Jagged1 of the ESCs in the siJagged1 group and bFGF + siJagged1 group was knocked down by small-interfering RNA transfection. Expression of ESC markers (CK15/CK10), MFB markers (α-SMA, Collagen I, Collagen III), and Notch1/Jagged1 components (Jagged1, Notch1, Hes1) was detected by FCM, qRT-PCR, and western blot analysis to study the relationships of bFGF, ESCs, and Notch1/Jagged1 pathway. In in-vivo study, the wound healing time and scar hyperplasia were observed on rabbit ear scar models. The quality of wound healing was estimated by hematoxylin and eosin staining and Masson staining. Expression of ESC markers, MFB markers and Notch1/Jagged1 components was elucidated by immunohistochemistry, immunofluorescence, and western blot analysis. RESULTS: The in-vitro study showed that bFGF could significantly upregulate the expression of ESC markers and Notch1/Jagged1 components, while downregulating the expression of MFB markers at the same time. However, these effects could be obviously decreased when we knocked down Jagged1 or added DAPT. Similarly, in in-vivo study, bFGF also exhibited its functions in inhibiting the differentiation of rabbit ESCs to MFB by activating the Notch1/Jagged1 pathway, which improved the wound healing quality and alleviated scar significantly. CONCLUSION: These results provide evidence that bFGF can reduce scar by inhibiting the differentiation of ESCs to MFB via the Notch1/Jagged1 pathway, and present a new promising potential direction for the treatment of scar.

Pre-vascularization Enhances Therapeutic Effects of Human Mesenchymal Stem Cell Sheets in Full Thickness Skin Wound Repair.

Split thickness skin graft (STSG) implantation is one of the standard therapies for full thickness wound repair when full thickness autologous skin grafts (FTG) or skin flap transplants are inapplicable. Combined transplantation of STSG with dermal substitute could enhance its therapeutic effects but the results remain unsatisfactory due to insufficient blood supply at early stages, which causes graft necrosis and fibrosis. Human mesenchymal stem cell (hMSC) sheets are capable of accelerating the wound healing process. We hypothesized that pre-vascularized hMSC sheets would further improve regeneration by providing more versatile angiogenic factors and pre-formed microvessels. In this work, in vitro cultured hMSC cell sheets (HCS) and pre-vascularized hMSC cell sheets (PHCS) were implanted in a rat full thickness skin wound model covered with an autologous STSG. Results demonstrated that the HCS and the PHCS implantations significantly reduced skin contraction and improved cosmetic appearance relative to the STSG control group. The PHCS group experienced the least hemorrhage and necrosis, and lowest inflammatory cell infiltration. It also induced the highest neovascularization in early stages, which established a robust blood micro-circulation to support grafts survival and tissue regeneration. Moreover, the PHCS grafts preserved the largest amount of skin appendages, including hair follicles and sebaceous glands, and developed the smallest epidermal thickness. The superior therapeutic effects seen in PHCS groups were attributed to the elevated presence of growth factors and cytokines in the pre-vascularized cell sheet, which exerted a beneficial paracrine signaling during wound repair. Hence, the strategy of combining STSG with PHCS implantation appears to be a promising approach in regenerative treatment of full thickness skin wounds.

Defects in dermal Vγ4 γ δ T cells result in delayed wound healing in diabetic mice.

The skin serves as a physical and chemical barrier to provide an initial line of defense against environmental threats; however, this function is impaired in diabetes. Vγ4 γ δ T cells in the dermis are an important part of the resident cutaneous immunosurveillance program, but these cells have yet to be explored in the context of diabetes. In this study, we observed that the impaired maintenance of dermal Vγ4 γ δ T cells is caused by reduced production of IL-7 in the skin of diabetic mice, which was closely associated with weakened activation of the mTOR pathway in the epidermis of diabetic mice. Weakened CCL20/CCR6 chemokine signaling resulted in the impaired recruitment of dermal Vγ4 γ δ T cells following wounding in diabetic mice. Meanwhile, reduced levels of IL-23 and IL-1ß in the dermis around the wounds of diabetic mice resulted in the impaired production of IL-17 by dermal Vγ4 γ δ T cells. Therefore, diminished dermal Vγ4 γ δ T cells and impaired IL-17 production by these cells were important factors in the markedly reduced IL-17 levels in the skin around the wounds of diabetic mice. Because reduced IL-17 levels at the wound edge have been closely associated with delayed wound closure in diabetic mice, defects in dermal Vγ4 γ δ T cells may be an important mechanism underlying delayed wound healing in diabetic mice.

Dendritic epidermal T cells facilitate wound healing in diabetic mice.

The impairment of skin repair in diabetic patients can lead to increased morbidity and mortality. Proper proliferation, apoptosis and migration in keratinocytes are vital for skin repair, but in diabetic patients, hyperglycemia impairs this process. Dendritic epidermal T cells (DETCs) are an important part of the resident cutaneous immunosurveillance program. We observed a reduction in the number of DETCs in a streptozotocin-induced diabetic mouse model. This reduction in DETCs resulted in decreased IGF-1 and KGF production in the epidermis, which is closely associated with diabetic delayed wound closure. DETCs ameliorated the poor wound-healing conditions in diabetic mice by increasing keratinocyte migration and proliferation and decreasing keratinocyte apoptosis in diabetes-like microenvironments. Our results elucidate a new mechanism for diabetic delayed wound closure and point to a new strategy for the treatment of wounds in diabetic patients.

Prostaglandin E2 inhibits collagen synthesis in dermal fibroblasts and prevents hypertrophic scar formation in vivo.

Hypertrophic scarring is a common dermal fibroproliferative disorder characterized by excessive collagen deposition. Prostaglandin E2 (PGE2 ), an important inflammatory product synthesized via the arachidonic acid cascade, has been shown to act as a fibroblast modulator and to possess antifibroblastic activity. However, the mechanism underlying the antifibrotic effect of PGE2 remains unclear. In this study, we explored the effects of PGE2 on TGF-ß1-treated dermal fibroblasts in terms of collagen production and to determine the regulatory pathways involved, as well as understand the antiscarring function of PGE2 in vivo. We found that PGE2 inhibited TGF-ß1-induced collagen synthesis by regulating the balance of matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinase (TIMP). It did so by upregulating cAMP through the E prostanoid (EP)2 receptor. We determined that inhibition of the TGF-ß1/Smad pathway by PGE2 is associated with its ability to inhibit collagen synthesis. An in vivo study further confirmed that PGE2 inhibits hypertrophic scar formation by decreasing collagen production. Our results demonstrate that the novel anti-scarring function of PGE2 is achieved by balancing MMPs/TIMP expression and decreasing collagen production.