miR-155 promotes cutaneous wound healing through enhanced keratinocytes migration by MMP-2

Progress in Wound-Healing Products Based on Natural Compounds, Stem Cells, and MicroRNA-Based Biopolymers in the European, USA, and Asian Markets: Opportunities, Barriers, and Regulatory Issues

Wounds are breaks in the continuity of the skin and underlying tissues, resulting from external causes such as cuts, blows, impacts, or surgical interventions. Countless individuals suffer minor to severe injuries, with unfortunate cases even leading to death. In today's scenario, several commercial products are available to facilitate the healing process of wounds, although chronic wounds still present more challenges than acute wounds. Nevertheless, the huge demand for wound-care products within the healthcare sector has given rise to a rapidly growing market, fostering continuous research and development endeavors for innovative wound-healing solutions. Today, there are many commercially available products including those based on natural biopolymers, stem cells, and microRNAs that promote healing from wounds. This article explores the recent breakthroughs in wound-healing products that harness the potential of natural biopolymers, stem cells, and microRNAs. A comprehensive exploration is undertaken, covering not only commercially available products but also those still in the research phase. Additionally, we provide a thorough examination of the opportunities, obstacles, and regulatory considerations influencing the potential commercialization of wound-healing products across the diverse markets of Europe, America, and Asia.

MicroRNA-155 mediates multiple gene regulations pertinent to the role of human adipose-derived mesenchymal stem cells in skin regeneration

Introduction: The role of Adipose-derived mesenchymal stem cells (AD-MSCs) in skin wound healing remains to be fully characterized. This study aims to evaluate the regenerative potential of autologous AD-MSCs in a non-healing porcine wound model, in addition to elucidate key miRNA-mediated epigenetic regulations that underlie the regenerative potential of AD-MSCs in wounds. Methods: The regenerative potential of autologous AD-MSCs was evaluated in porcine model using histopathology and spatial frequency domain imaging. Then, the correlations between miRNAs and proteins of AD-MSCs were evaluated using an integration analysis in primary human AD-MSCs in comparison to primary human keratinocytes. Transfection study of AD-MSCs was conducted to validate the bioinformatics data. Results: Autologous porcine AD-MSCs improved wound epithelialization and skin properties in comparison to control wounds. We identified 26 proteins upregulated in human AD-MSCs, including growth and angiogenic factors, chemokines and inflammatory cytokines. Pathway enrichment analysis highlighted cell signalling-associated pathways and immunomodulatory pathways. miRNA-target modelling revealed regulations related to genes encoding for 16 upregulated proteins. miR-155-5p was predicted to regulate Fibroblast growth factor 2 and 7, C-C motif chemokine ligand 2 and Vascular cell adhesion molecule 1. Transfecting human AD-MSCs cell line with anti-miR-155 showed transient gene silencing of the four proteins at 24 h post-transfection. Discussion: This study proposes a positive miR-155-mediated gene regulation of key factors involved in wound healing. The study represents a promising approach for miRNA-based and cell-free regenerative treatment for difficult-to-heal wounds. The therapeutic potential of miR-155 and its identified targets should be further explored in-vivo.

Exosomes derived from adipose tissues accelerate fibroblasts and keratinocytes proliferation and cutaneous wound healing via miR-92a/Hippo-YAP axis

Delayed wound healing is an urgent clinical issue. Cellular communication involving exosome-borne cargo such as miRNA is a critical mechanism involved in wound healing. This study isolated and identified human adipose tissue-derived exosomes (Exo-ATs). The specific effects of Exo-ATs on keratinocytes and fibroblasts were examined. Enriched miRNAs in Exo-ATs were analyzed, and miR-92a-3p was selected. The transfer of Exo-ATs-derived miR-92a-3p to keratinocytes and fibroblasts was verified. miR-92a-3p binding to LATS2 was examined and the dynamic effects of the miR-92a-3p/LATS2 axis were investigated. In a dorsal skin wound model, the in vivo effects of Exo-ATs on wound healing were examined. Exo-AT incubation increased keratinocytes and fibroblast proliferation, migration, and extracellular matrix (ECM) accumulation. miR-92a-3p, enriched in Exo-ATs, could be transferred to keratinocytes and fibroblasts, resulting in enhanced proliferation, migration, and ECM accumulation. Large tumor suppressor kinase 2 (LATS2) was a direct target of miR-92a-3p. miR-92a-3p inhibitor effects on keratinocytes and fibroblasts could be partially reversed by LATS2 knockdown. In a dorsal skin wound model, Exo-ATs accelerated wound healing through enhanced cell proliferation, collagen deposition, re-epithelialization, and YAP/TAZ activation. In conclusion, Exo-ATs improve skin wound healing by promoting keratinocyte and fibroblast migration and proliferation and collagen production by fibroblast, which could be partially eliminated by miR-92a inhibition through its downstream target LATS2 and the YAP/TAZ signaling.

Safety and Effectiveness of Laser or Intense Pulsed Light Treatment for Early Surgical Scar: A Systematic Review and Meta-analysis

OBJECTIVE

We aimed to investigate the safety and efficacy of laser or intense pulsed light therapy for early treatment of surgical scar.

METHODS

A literature search was conducted for relevant prospective, randomized controlled trials published in PubMed, Embase, Web of Science, Cochrane Library, CNKI, WanFang Database, and VTTMS between January 2006 and January 2022. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist was used to extract literature data. The risk of bias was assessed by RevMan. Safety was assessed based on the presence of serious adverse reactions (blisters, infections, burns above the second degree), while effectiveness was assessed using the Vancouver Score Scale.

RESULTS

1512 related articles were preliminarily retrieved, including 1211 English articles and 301 Chinese articles. According to the inclusion criteria and exclusion criteria, 12 articles were selected for this analysis. In total, 475 patients were included (laser group, 238; control group, 236). All studies confirmed that the laser group was superior to the control group. In the subgroup analysis of 7 articles, the standardized mean difference was 1.99 (P = 0.0001).

CONCLUSIONS

This meta-analysis demonstrates that laser or intense pulsed light therapy is a safe and effective approach for early surgical scar treatment, resulting in improved scar appearance and minimal adverse reactions.

LEVEL OF EVIDENCE I

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Changes in gene expression in pressure ulcers debrided by different approaches - a pilot study

Pressure ulcers (PUs), also known as pressure injuries, are chronic wounds that represent potential lifelong complications. Pressure ulcers of a deep category (III and IV) are often indicated for surgical treatment - debridement and surgical reconstruction. Sharp surgical debridement is widely used in the debridement of PUs; however, the Versajet® hydrosurgery system is becoming an increasingly popular tool for tangential excision in surgery due to its numerous advantages. This work focused on the expression of selected genes, especially those associated with oxidative stress, in PUs debrided by two approaches - sharp surgical debridement and debridement using Versajet® hydrosurgery system. Expression of following genes was evaluated: NFE2L2, ACTA2, NFKB1, VEGFA, MKI67, HMOX1, HMOX2, HIF1A, and SOD2. ACTB and PSMB were used as housekeeping genes. So far, five patients have been enrolled in the study. Preliminary results suggest no significant difference in gene expression with different pressure ulcer treatment approaches except NFE2L2, despite the macroscopic differences. However, the results revealed correlations between the expression of some genes, namely HIF1A and SOD2, VEGFA and SOD2 and VEGFA and HIF1A. These results may indicate a connection between hypoxia, oxidative stress, pressure ulcer healing processes and angiogenesis.

Therapeutic inhibition of miR-155 attenuates liver fibrosis via STAT3 signaling

Most chronic liver diseases progress to liver fibrosis, which, when left untreated, can lead to cirrhosis and hepatocellular carcinoma. MicroRNA (miRNA)-targeted therapeutics have become attractive approaches to treat diseases. In this study, we investigated the therapeutic effect of miR-155 inhibition in the bile duct ligation (BDL) mouse model of liver fibrosis and evaluated the role of miR-155 in chronic liver fibrosis using miR-155-deficient (miR-155 knockout [KO]) mice. We found increased hepatic miR-155 expression in patients with cirrhosis and in the BDL- and CCl4-induced mouse models of liver fibrosis. Liver fibrosis was significantly reduced in miR-155 KO mice after CCl4 administration or BDL. To assess the therapeutic potential of miR-155 inhibition, we administered an rAAV8-anti-miR-155 tough decoy in vivo that significantly reduced liver damage and fibrosis in BDL. BDL-induced protein levels of transforming growth factor β (TGF-β), p-SMAD2/3, and p-STAT3 were attenuated in anti-miR-155-treated compared with control mice. Hepatic stellate cells from miR-155 KO mice showed attenuation in activation and mesenchymal marker expression. In vitro, miR-155 gain- and loss-of-function studies revealed that miR-155 regulates activation of stellate cells partly via STAT3 signaling. Our study suggests that miR-155 is the key regulator of liver fibrosis and might be a potential therapeutic target to attenuate fibrosis progression.

miR-100-5p Promotes Epidermal Stem Cell Proliferation through Targeting MTMR3 to Activate PIP3/AKT and ERK Signaling Pathways

Skin epidermal stem cells (EpSCs) play a critical role in wound healing and are ideal seed cells for skin tissue engineering. Exosomes from human adipose-derived stem cells (ADSC-Exos) promote human EpSC proliferation, but the underlying mechanism remains unclear. Here, we investigated the effect of miR-100-5p, one of the most abundant miRNAs in ADSC-Exos, on the proliferation of human EpSCs and explored the mechanisms involved. MTT and BrdU incorporation assays showed that miR-100-5p mimic transfection promoted EpSC proliferation in a time-dependent manner. Cell cycle analysis showed that miR-100-5p mimic transfection significantly decreased the percentage of cells in the G1 phase and increased the percentage of cells in the G2/M phase. Myotubularin-related protein 3 (MTMR3), a lipid phosphatase, was identified as a direct target of miR-100-5p. Knockdown of MTMR3 in EpSCs by RNA interference significantly enhanced cell proliferation, decreased the percentage of cells in the G1 phase and increased the percentage of cells in the S phase. Overexpression of MTMR3 reversed the proproliferative effect of miR-100-5p on EpSCs, indicating that miR-100-5p promoted EpSC proliferation by downregulating MTMR3. Mechanistic studies showed that transfection of EpSCs with miR-100-5p mimics elevated the intracellular PIP3 level, induced AKT and ERK phosphorylation, and upregulated cyclin D1, E1, and A2 expression, which could be attenuated by MTMR3 overexpression. Consistently, intradermal injection of ADSC-Exos or miR-100-5p-enriched ADSC-Exos into cultured human skin tissues significantly reduced MTMR3 expression and increased the thickness of the epidermis and the number of EpSCs in the basal layer of the epidermis. The aforementioned effect of miR-100-5p-enriched ADSC-Exos was stronger than that of ADSC-Exos and was reversed by MTMR3 overexpression. Collectively, our findings indicate that miR-100-5p promotes EpSC proliferation through MTMR3-mediated elevation of PIP3 and activation of AKT and ERK. miR-100-5p-enriched ADSC-Exos can be used to treat skin wound and expand EpSCs for generating epidermal autografts and engineered skin equivalents.

Landscape of the epigenetic regulation in wound healing

Wound healing after skin injury is a dynamic and highly coordinated process involving a well-orchestrated series of phases, including hemostasis, inflammation, proliferation, and tissue remodeling. Epigenetic regulation refers to genome-wide molecular events, including DNA methylation, histone modification, and non-coding RNA regulation, represented by microRNA (miRNA), long noncoding RNA (lncRNA), and circular RNA (circRNA). Epigenetic regulation is pervasively occurred in the genome and emerges as a new role in gene expression at the post-transcriptional level. Currently, it is well-recognized that epigenetic factors are determinants in regulating gene expression patterns, and may provide evolutionary mechanisms that influence the wound microenvironments and the entire healing course. Therefore, this review aims to comprehensively summarize the emerging roles and mechanisms of epigenetic remodeling in wound healing. Moreover, we also pose the challenges and future perspectives related to epigenetic modifications in wound healing, which would bring novel insights to accelerated wound healing.

Mesenchymal Stem Cell-Derived Exosomes Loaded with miR-155 Inhibitor Ameliorate Diabetic Wound Healing

Diabetic wounds are one of the debilitating complications that affect up to 20% of diabetic patients. Despite the advent of extensive therapies, the recovery rate is unsatisfactory, and approximately, 25% of patients undergo amputation, thereby demanding alternative therapeutic strategies. On the basis of the individual therapeutic roles of the miR-155 inhibitor and mesenchymal stem cells (MSC)-derived exosomes, we conjectured that the combination of the miR-155 inhibitor and MSC-derived exosomes would have synergy in diabetic wound healing. Herein, miR-155-inhibitor-loaded MSC-derived exosomes showed synergistic effects in keratinocyte migration, restoration of FGF-7 levels, and anti-inflammatory action, leading to accelerated wound healing mediated by negative regulation of miR-155, using an in vitro co-culture model and in vivo mouse model of the diabetic wound. Furthermore, treatment with miR-155-inhibitor-loaded MSC-derived exosomes led to enhanced collagen deposition, angiogenesis, and re-epithelialization in diabetic wounds. This study revealed the therapeutic potential of miR-155-inhibitor-loaded MSC-derived exosomes in diabetic wound healing and opened the doors for encapsulating miRNAs along with antibiotics within the MSC-derived exosomes toward improved management of chronic, nonhealing diabetic wounds.

Platelet-Released Growth Factors Influence Wound Healing-Associated Genes in Human Keratinocytes and Ex Vivo Skin Explants

Platelet-released growth factors (PRGFs) or other thrombocyte concentrate products, e.g., Platelet-Rich Fibrin (PRF), have become efficient tools of regenerative medicine in many medical disciplines. In the context of wound healing, it has been demonstrated that treatment of chronic or complicated wounds with PRGF or PRF improves wound healing in the majority of treated patients. Nevertheless, the underlying cellular and molecular mechanism are still poorly understood. Therefore, we aimed to analyze if PRGF-treatment of human keratinocytes caused the induction of genes encoding paracrine factors associated with successful wound healing. The investigated genes were Semaphorin 7A (SEMA7A), Angiopoietin-like 4 (ANGPLT4), Fibroblast Growth Factor-2 (FGF-2), Interleukin-32 (IL-32), the CC-chemokine-ligand 20 (CCL20), the matrix-metalloproteinase-2 (MMP-2), the chemokine C-X-C motif chemokine ligand 10 (CXCL10) and the subunit B of the Platelet-Derived Growth Factor (PDGFB). We observed a significant gene induction of SEMA7A, ANGPLT4, FGF-2, IL-32, MMP-2 and PDGFB in human keratinocytes after PRGF treatment. The CCL20- and CXCL10 gene expressions were significantly inhibited by PRGF therapy. Signal transduction analyses revealed that the PRGF-mediated gene induction of SEMA7A, ANGPLT4, IL-32 and MMP-2 in human keratinocytes was transduced via the IL-6 receptor pathway. In contrast, EGF receptor signaling was not involved in the PRGF-mediated gene expression of analyzed genes in human keratinocytes. Additionally, treatment of ex vivo skin explants with PRGF confirmed a significant gene induction of SEMA7A, ANGPLT4, MMP-2 and PDGFB. Taken together, these results describe a new mechanism that could be responsible for the beneficial wound healing properties of PRGF or related thrombocytes concentrate products such as PRF.

Increased Expression of miR-155 in Peripheral Blood and Wound Margin Tissue of Type 2 Diabetes Mellitus Patients Associated with Diabetic Foot Ulcer

PURPOSE

To investigate the correlations of miR-155 expression in the peripheral blood and wound margin tissue of patients with diabetic foot ulcer (DFU) and explore the clinical value of miR-155 as a potential biomarker for the diagnosis and treatment outcomes of DFU.

METHODS

Sixty newly diagnosed T2DM patients without DFU (T2DM group), 112 T2DM patients with DFU (DFU group), and 60 healthy controls (NC group) were included. MiR-155 levels in the peripheral blood and wound margin tissue were determined by quantitative real-time PCR, while clinical features and risk factors of DFU were explored. Multiple stepwise logistic regression analysis was used to determine whether miR-155 expression was an independent risk factor for DFU. The diagnostic effectiveness of miR-155 level on DFU was evaluated using ROC curve analysis.

RESULTS

A significant decrease in the expression level of miR-155 was observed in T2DM group compared with NC group (P < 0.05), while a markedly increased miR-155 expression level was noted in DFU group compared with T2DM group (P < 0.01). Moreover, there was a negative correlation between the expression levels of miR-155 with healing rate of DFU. Kaplan-Meier survival curve analysis showed that the cumulative rate of unhealed DFU in miR-155 high expression group is higher than that in miR-155 low expression group, both in peripheral blood and wound margin tissue (log rank, P = 0.004, P < 0.001, respectively). The multivariate logistic regression analysis confirmed that a high expression of miR-155 was an independent risk factor for DFU. The ROC curve analysis indicated that the AUC of miR-155 for the diagnosis of DFU was 0.794, with the optimum sensitivity being 96.82% and the optimum specificity of 95.93%.

CONCLUSION

The increased expression of miR-155 in peripheral blood of T2DM patients is closely related to the occurrence of DFU. MiR-155 is a potentially valuable biomarker for diagnosis and prognosis of DFU.

Steatosis, inflammasome upregulation, and fibrosis are attenuated in miR-155 deficient mice in a high fat-cholesterol-sugar diet-induced model of NASH

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease globally. miRNAs (miRs) regulate various cellular events that lead to NAFLD. In this study we tested the hypothesis that miR-155 is an important regulator of steatohepatitis and fibrosis pathways. Wild type (WT) or miR-155 deficient (KO) mice received a high fat-high cholesterol-high sugar-diet (HF-HC-HS) for 34 weeks and liver tissues were analyzed. In patients with nonalcoholic steatohepatitis and in the mouse model of HF-HC-HS diet we found increased miR-155 levels in the liver compared to normal livers. Upon HF-HC-HS diet feeding, miR-155 KO mice displayed less liver injury, decreased steatosis, and attenuation in fibrosis compared to WT mice. ALT, triglyceride levels, and genes involved in fatty acid metabolic pathway were increased in WT mice whereas miR-155 KO mice showed attenuation in these parameters. HF-HC-HS diet-induced significant increase in the expression of NLRP3 inflammasome components in the livers of WT mice compared to chow fed diet. Compared to WT mice, miR-155 KO showed attenuated induction in the NLRP3, ASC, and caspase1 inflammasome expression on HF-HC-HS diet. Fibrosis markers such as collagen content and deposition, αSMA, Zeb2, and vimentin were all increased in WT mice and miR-155 KO mice showed attenuated fibrosis marker expression. Overall, our findings highlight a role for miR-155 in HF-HC-HS diet-induced steatosis and liver fibrosis.

Topical application of metformin accelerates cutaneous wound healing in streptozotocin-induced diabetic rats

BACKGROUND

Diabetic chronic wound, which is one of the diabetic complications caused by hyperglycemia, characterized by prolonged inflammation has become one of the most serious challenges in the clinic. Hyperglycemia during diabetes not only causes prolonged inflammation and delayed wound healing but also modulates the activation of nuclear factor-kappa B (NF-κB) and the expression of matrix metalloproteinases (MMPs). Although metformin is the oldest oral antihyperglycemic drug commonly used for treating type 2 diabetes, few studies have explored the molecular mechanism of its topical effect on wound healing. Therefore, we aimed to investigate the molecular effects of topical metformin application on delayed wound healing, which's common in diabetes.

METHODS AND RESULTS

In this context, we created a full-thickness excisional wound model in Wistar albino rats and, investigated NF-κB p65 DNA-binding activity and expression levels of RELA (p65), MMP2 and MMP9 in wound samples taken on days 0, 3, 7, and 14 from diabetic/non-diabetic rats treated with metformin and saline. As a result of our study, we showed that topically applied metformin accelerates wound healing by suppressing NF-κB p65 activity and diminishing the expression of MMP2 and MMP9.

CONCLUSIONS

Diabetic wounds treated with metformin healed even faster than those in the control group that mimicked standard wound healing.

Differential regulation of miR-21-5p delays wound healing of melanocyte-deprived vitiligo skin by modulating the expression of tumor-suppressors PDCD4 and Maspin

The loss of melanocytes in vitiligo is associated with architectural, transcriptional, and cellular perturbations of keratinocytes and manifests as a reduced proliferation potential in vitro and delayed re-epithelialization in vivo. To understand the molecular mechanisms underlying this delay, microRNA (miRNA) profiling was performed on split skin biopsies collected on Day 1 (basal level) and Day 14 (wound re-epithelialization) from nonlesional (NL) and lesional (L) skin of five subjects with stable nonsegmental vitiligo and 129 miRNAs were found to be differentially regulated between the NL and L healed epidermis. miR-21-5p, expressed at comparable levels on NL and L Day 1 samples, demonstrated significant upregulation during re-epithelialization. However, the extent of its upregulation was relatively lower in L (10 times compared to Day 1) as compared to NL skin (17 times compared to Day 1). The overexpression of miR-21 in keratinocytes led to a significant increase in the expression of proliferation markers (Ki67 and MCM6 messenger RNA, Ki67 positivity), along with an increase in keratinocyte migration. Using a small interfering RNA mediated knockdown approach, we further demonstrated that miR-21-5p mediates its effects by suppressing the expression of programmed cell death 4 (PDCD4) and mammary serine protease inhibitor (Maspin), both tumor-suppressor genes. Investigation of clinical samples corroborated the lower miR-21 levels and a higher expression of PDCD4 and Maspin in L Day 14 compared to the NL Day 14 epidermis. In conclusion, this study revealed that a relatively lower upregulation of miR-21-5p in L skin leads to significantly higher levels of PDCD4 and Maspin, delaying wound re-epithelialization by reducing the proliferation and migration of keratinocytes.

Resveratrol promotes skin wound healing by regulating the miR-212/CASP8 axis

The wound-healing process is a natural response to burn injury. Resveratrol (RES) may have potential as a therapy for wound healing, but how and whether RES regulates skin repair remains poorly understood. Human epidermal keratinocyte (HaCaT) cells were treated with lipopolysaccharide (LPS), and a mouse skin wound-healing model was established. Cell viability and apoptosis were analyzed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide or flow cytometry. Cell proliferation was assessed by cell viability and colony-formation analyses. Cell migration was tested by wound-healing analysis. The microRNA-212 (miR-212) and caspase-8 (CASP8) levels were determined by quantitative reverse transcription polymerase chain reaction and western blotting. The correlation between miR-212 and CASP8 was analyzed by dual-luciferase reporter analysis. Skin wound healing in mice was assessed by measuring the wound area and gap after hematoxylin-eosin (HE) staining. RES reduced the LPS-induced reduction in viability and apoptosis in HaCaT cells. miR-212 expression was reduced by LPS and increased by exposure to RES. RES promoted cell proliferation and migration after LPS treatment by increasing miR-212 levels. CASP8 was a target of miR-212. CASP8 silencing promoted cell proliferation and migration, which was reversed by miR-212 knockdown in LPS-treated HaCaT cells. RES promoted skin wound healing in mice, which was reduced by miR-212 knockdown. Thus, RES facilitates cell proliferation and migration in LPS-treated HaCaT cells and promotes skin wound-healing in a mouse model by regulating the miR-212/CASP8 axis.

Circ_PRKDC knockdown promotes skin wound healing by enhancing keratinocyte migration via miR-31/FBN1 axis

Circular RNA protein kinase, DNA-activated, catalytic subunit (circ_PRKDC) has been found to impede wound healing in diabetic foot ulcers via regulating keratinocyte proliferation and migration. However, the mechanisms underlying circ_PRKDC in skin wound healing remain unclear. The expression of circ_PRKDC, microRNA (miR)-31 and fibrillin 1 (FBN1) was detected using quantitative reverse transcription-polymerase chain reaction and Western blot assays. The migration ability and the changes of matrix metallopeptidase 9 (MMP-9) and MMP2 levels were determined using wound healing, transwell and Western blot assays. The interaction between miR-31 and circ_PRKDC or FBN1 was verified by dual-luciferase reporter assay. The expression of circ_PRKDC was gradually down-regulated in wound edge at 1 and 7 days after injury relative to the unwounded skin. In human epidermal keratinocytes (HEKa), knockdown of circ_PRKDC promoted cell migration partly through up-regulating MMP-2 and MMP9, while circ_PRKDC overexpression showed opposite effects. In a mechanical study, we confirmed that miR-31 was a target of circ_PRKDC, and inhibition of miR-31 reversed the promotive effect of circ_PRKDC knockdown on HEKa migration. Besides that, miR-31 was verified to target FBN1, and ectopic overexpression of miR-31 accelerated HEKa migration via FBN1. Importantly, we also demonstrated that FBN1 overexpression attenuated the effects of circ_PRKDC knockdown on HEKa migration. In all, circ_PRKDC knockdown promoted HEKa migration during wound healing through miR-31/FBN1 axis, suggesting the therapeutic potential for circ_PRKDC on skin wound healing.

Human Adipose-Derived Mesenchymal Stem Cells-Derived Exosomal microRNA-19b Promotes the Healing of Skin Wounds Through Modulation of the CCL1/TGF-β Signaling Axis

Introduction

Human adipose-derived mesenchymal stem cells (ADMSCs) with their secretory factors are able to induce collagen synthesis and fibroblast migration in the wound healing process. This study is launched to figure out the effect of human ADMSCs-derived exosomes on skin wound healing.

Methods

ADMSCs were extracted and ADMSCs-derived exosomes were identified. Skin damage models were established by treating HaCaT cells and human skin fibroblasts with H₂O₂. Next, the roles of ADMSCs and their derived exosomes were investigated. The exosomal miRNA then was analyzed, and the function of miRNA on the H₂O₂-induced cells was studied by miRNA suppression. Bioinformatics analysis, luciferase activity and RIP assays were implemented to find the target genes ofthe miRNA and the modulated pathways. A mouse skin damage model was induced to elucidate the effects of exosomes in vivo by injecting exosomes.

Results

H₂O₂ treatment significantly reduced the viability of HaCaT cells and increased their apoptosis rate. Co-culture with ADMSCs or their derived exosomes could improve the cell damage caused by H₂O₂. Meanwhile, H₂O₂ treatment promoted the internalization of exosomes. ADMSCs and their derived exosomes significantly increased miR-19b expression in the recipient cells, while inhibiting miR-19b resulted in a reduction in the therapeutic effect of ADMSCs-derived exosomes. Besides, miR-19b regulated the TGF-β pathway by targeting CCL1. The therapeutic effect of exosomes was further confirmed by a mouse model of skin damage.

Conclusion

Our study indicates that exosomal miR-19b derived from ADMSCs regulates the TGF-β pathway by targeting CCL1, thereby promoting the healing of skin wounds.

Potential Applications of Nanomaterials and Technology for Diabetic Wound Healing

Diabetic wound shows delayed and incomplete healing processes, which in turn exposes patients to an environment with a high risk of infection. This article has summarized current developments of nanoparticles/hydrogels and nanotechnology used for promoting the wound healing process in either diabetic animal models or patients with diabetes mellitus. These nanoparticles/hydrogels promote diabetic wound healing by loading bioactive molecules (such as growth factors, genes, proteins/peptides, stem cells/exosomes, etc.) and non-bioactive substances (metal ions, oxygen, nitric oxide, etc.). Among them, smart hydrogels (a very promising method for loading many types of bioactive components) are currently favored by researchers. In addition, nanoparticles/hydrogels can be combined with some technology (including PTT, LBL self-assembly technique and 3D-printing technology) to treat diabetic wound repair. By reviewing the recent literatures, we also proposed new strategies for improving multifunctional treatment of diabetic wounds in the future.

Mechanistic Actions of microRNAs in Diabetic Wound Healing

Wound healing is a complex biological process that is impaired under diabetes conditions. Chronic non-healing wounds in diabetes are some of the most expensive healthcare expenditures worldwide. Early diagnosis and efficacious treatment strategies are needed. microRNAs (miRNAs), a class of 18-25 nucleotide long RNAs, are important regulatory molecules involved in gene expression regulation and in the repression of translation, controlling protein expression in health and disease. Recently, miRNAs have emerged as critical players in impaired wound healing and could be targets for potential therapies for non-healing wounds. Here, we review and discuss the mechanistic background of miRNA actions in chronic wounds that can shed the light on their utilization as specific wound healing biomarkers.

Ganoderma lucidum Ethanol Extracts Enhance Re-Epithelialization and Prevent Keratinocytes from Free-Radical Injury

Ganoderma lucidum or Reishi is recognized as the most potent adaptogen present in nature, and its anti-inflammatory, antioxidant, immunomodulatory and anticancer activities are well known. Moreover, lately, there has been an increasing interest from pharmaceutical companies in antiaging G. lucidum-extract-based formulations. Nevertheless, the pharmacological mechanisms of such adaptogenic and regenerative actions remain unclear. The present investigation aimed to explore its molecular and cellular effects in vitro in epidermal keratinocyte cultures by applying liquid chromatography coupled to ion trap time-of-flight mass spectrometry (LCMS-IT-TOF) for analysis of ethanol extracts using ganoderic acid-A as a reference compound. The G. lucidum extract showed a keratinocyte proliferation induction accompanied by an increase of cyclic kinase protein expressions, such as CDK2 and CDK6. Furthermore, a noteworthy migration rate increase and activation of tissue remodelling factors, such as matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9), were observed. Finally, the extract showed an antioxidant effect, protecting from H₂O₂-induced cytotoxicity; preventing activation of AKT (protein kinase B), ERK (extracellular signal-regulated kinase), p53 and p21; and reducing the number of apoptotic cells. Our study paves the path for elucidating pharmacological properties of G. lucidum and its potential development as cosmeceutical skin products, providing the first evidence of its capability to accelerate the healing processes enhancing re-epithelialization and to protect cells from free-radical action.

MMP-2 and TIMP-2 expression, quantitative analysis and biomechanical changes in scar hypertrophy after autologous free transplantation of rabbit oral mucosa and scrotal skin

This study aimed to investigate the long-term scar hypertrophy in the rabbit transplanted oral mucosa and scrotal skin with changed matrix environment, as well as the scar location expression, quantitative analysis of matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-2 (TIMP-2) and biomechanical changes in the transplanted tissues. The split-thickness skin grafts were collected from the oral mucosas and scrotal skins of 30 male rabbits, and prepared into reelpipes for autologous transplantation into the rabbit back muscular tissues. Samples were collected to carry out elastic tensile mechanical detection and histological observation. The maximum longitudinal tensile displacement of scrotal skin before 8 weeks of transplantation was greater than that after 8 weeks of transplantation (P < 0.05). The expression intensities of MMP-2 and TIMP-2 in the oral mucosa and in scrotal skin at 2 W time point were higher than those at T _o time point (P < 0.05). The expression quantities of TIMP-2 in oral mucosa and scrotal skin during 8-24 W were higher than those of MMP-2 (P < 0.05). At 8 W time point, the TIMP-2/MMP-2 ratio in scrotal skin was higher than that in oral mucosa (P < 0.05). MMP-2 and TIMP-2 expression in normal oral mucosa and scrotal skin is weak, but their expression is remarkably up-regulated after 2 weeks of transplantation, revealing that scar formation was related to the high expression of MMP-2 and TIMP-2. At the 8th-24th weeks, the AOD values of TIMP-2 in oral mucosa and scrotal skin are apparently higher than those of MMP-2; moreover, the TIMP-2/MMP-2 ratio in scrotal skin at the 8th week was higher than that in oral mucosa, which can well explain the earlier scar formation in scrotal skin than in oral mucosa, and it also suggests that the different expression levels between TIMP-2 and MMP-2 may account for the important cause of scar formation.

Natural SIRT1 modifiers as promising therapeutic agents for improving diabetic wound healing

BACKGROUND

The occurrence of chronic wounds, account for significant suffering of diabetic people, together with increasing healthcare burden. The chronic wounds associated with diabetes do not undergo the normal healing process rather stagnate into chronic proinflammatory phase as well as declined fibroblast function and impaired cell migration.

HYPOTHESIS

SIRT1, which is the most studied isoform of the sirtuin family in mammals, has now emerged as a crucial target for improving diabetic wound healing. It is an NAD+ dependent deacetylase, originally characterized to deacetylate histone proteins leading to heterochromatin formation and gene silencing. It is now known to regulate a number of cellular processes like cell proliferation, division, senescence, apoptosis, DNA repair, and metabolism.

METHODOLOGY

The retrieval of potentially relevant studies was done by systematically searching of three databases (Google Scholar, Web of science and PubMed) in December 2019. The keywords used as search terms were related to SIRT1 and wound healing. The systematic search retrieved 649 papers that were potentially relevant and after selection procedure, 73 studies were included this review and discussed below.

RESULTS

Many SIRT1 activating compounds (SACs) were found protective and improve diabetic wound healing through regulation of inflammation, cell migration, oxidative stress response and formation of granulation tissue at the wound site.

CONCLUSIONS

However, contradictory reports describe the opposing role of SACs on the regulation of cell migration and cancer incidence. SACs are therefore subjected to intense research for understanding the mechanisms responsible for controlling cell migration and therefore possess prospective to enter the clinical arena in the foreseeable future.

ADSC-Exos containing MALAT1 promotes wound healing by targeting miR-124 through activating Wnt/β-catenin pathway

Cutaneous wound is a soft tissue injury that is difficult to heal during aging. It has been demonstrated that adipose-derived stem cells (ADSCs) and its secreted exosomes exert crucial functions in cutaneous wound healing. The present study aimed to elucidate the mechanism of exosomes derived from ADSCs (ADSC-Exos) containing MALAT1 in wound healing. ADSCs were isolated from human normal subcutaneous adipose tissues and identified by flow cytometry analysis. Exosomes were extracted from ADSC supernatants and MALAT1 expression was determined using qRT-PCR analysis. HaCaT and HDF cells were exposed to hydrogen peroxide (H2O2) for simulating the skin lesion model. Subsequently, CCK-8, flow cytometry, wound healing and transwell assays were employed to validate the role of ADSC-Exos containing MALAT1 in the skin lesion model. Besides, cells were transfected with sh-MALAT1 to verify the protective role of MALAT1 in wound healing. The binding relationship between MALAT1 and miR-124 were measured by dual-luciferase reporter assay. ADSC-Exos promoted cell proliferation, migration, and inhibited cell apoptosis of HaCaT and HDF cells impaired by H2O2. However, the depletion of MALAT1 in ADSC-Exos lose these protective effects on HaCaT and HDF cells. Moreover, miR-124 was identified to be a target of MALAT1. Furthermore, ADSC-Exos containing MALAT1 could mediate H2O2-induced wound healing by targeting miR-124 and activating Wnt/β-catenin pathway. ADSC-Exos containing MALAT1 play a positive role in cutaneous wound healing possibly via targeting miR-124 through activating the Wnt/β-catenin pathway, which may provide novel insights into the therapeutic target for cutaneous wound healing.

GelMA combined with sustained release of HUVECs derived exosomes for promoting cutaneous wound healing and facilitating skin regeneration

It remains a clinical challenge for cutaneous wound healing and skin regeneration. Endothelial cells participate in the formation of blood vessels and play an important role in the whole process of wound healing. Recent studies suggested that exosomes contribute to the intercellular communication through paracrine pathways, and sustained release of exosomes from hydrogel-based materials provide a promising strategy for curing wound defects. In this study, we isolated exosomes derived from human umbilical vein endothelial cells (HUVECs) and found that HUVECs derived exosomes (HUVECs-Exos) could promote the proliferation and migration activities of keratinocytes and fibroblasts, which are two important effector cells for skin regeneration. Then we developed gelatin methacryloyl (GelMA) hydrogel as the wound dressing to incorporate HUVECs-Exos and applied it to the full-thickness cutaneous wounds. It demonstrated that GelMA scaffold could not only repair the wound defect, but also achieve sustained release of exosomes. The in vivo results showed accelerated re-epithelialization, promotion of collagen maturity and improvement of angiogenesis. Collectively, our findings suggested that HUVECs-Exos could accelerate wound healing and GelMA mediated controlled release of HUVECs-Exos might offer a new method for repairing cutaneous wound defects.

Identification of differentially expressed miRNAs associated with thermal injury in epidermal stem cells based on RNA-sequencing

Current research indicates that epidermal stem cells (EpSCs) play an important role in promoting wound healing, but the mechanism of action of these cells during wound repair following thermal damage remains unclear. In the present study, the trypsin digestion method was used to isolate human EpSCs and the cells were incubated in a 51.5°C water tank for 35 sec to construct a thermal injury model. The differentially expressed miRNAs were identified using high-throughput sequencing technology, and bioinformatic methods were used to predict their target genes and signaling pathways that may be involved in wound repair. A total of 33 miRNAs including, hsa-miR-1973, hsa-miR-4485-3p, hsa-miR-548-5p, hsa-miR-212-3p and hsa-miR-4461 were upregulated, whereas 21 miRNAs including, hsa-miR-4520-5p, hsa-miR-4661-5p, hsa-miR-191-3p, hsa-miR-129-5p, hsa-miR-147b and hsa-miR-6868-3p were downregulated following thermal injury of the human EpSCs. The bioinformatic analysis indicated that the differentially expressed miRNAs are involved in biological processes such as cell proliferation and differentiation, cell growth apoptosis, cell adhesion and migration. The results showed that there is a differential expression pattern of miRNAs after thermal injury of human EpSCs and these differences are involved in the regulation of the wound healing process. These findings provide new clues for further study of the wound healing mechanism and targeted therapy.

Inhibition of matrix metalloproteinase-2 modulates malignant behaviour of oral squamous cell carcinoma cells

BACKGROUND

Matrix metalloproteinases (MMPs) play a crucial role in the malignant phenotype of cancer cells. In particular, active levels of MMP2 in cancer cells have been associated with invasion and metastasis through the degradation of basement membrane extracellular matrix proteins. However, little is known about the role of this potential biomarker in oral cancer. Our aim was to investigate the effect of MMP2 inhibition on OSCC activity in vitro, as well as to assess MMP2 dysregulation in oral cancer samples.

METHODS

Human OSCC cell lines H357 and H400 were tested with the selective MMP2 inhibitor ARP101 and the MMP2 neutralising monoclonal antibody MA5-13590 to assess cell proliferation in vitro using MTS assay. Cell migration at 12/24 h was assessed using a Transwell migration assay. Cell invasion was assessed at 24 h using a Corning Matrigel invasion assay. MMP2 expression was assessed in 208 tissue samples (related to 60 OSCC cases and nine normal control) using tissue microarray (TMA) and further analysed via TCGA.

RESULTS

Both ARP101 and MA5-13590 monoclonal antibody reduced cell proliferation in both the cell lines tested. Treatment with 4μg/mL of MMP2 monoclonal antibody showed a significant decrease in cell migration at 24 hours. The administration of ARP101 and monoclonal antibody to H357 and H400 cell lines induced a drastic reduction in cell invasion at 24 h compared to the control. In patients, TCGA analysis demonstrated that oral cancer tissues express significantly higher levels of MMP2 mRNA compared to normal oral tissues. Further, IHC analysis on TMA showed significant difference in MMP2 protein expression between low and high histopathological grade OSCC.

CONCLUSIONS

We have demonstrated, for the first time, that MMP2 inhibition affects oral cancer cells ability to survive, migrate and invade in vitro. Differences between MMP2 expression in normal and malignant tissues varied. Further research on the role of MMP2 in OSCC and novel mechanisms to inhibit MMP2-dependent pathways should be encouraged.

MiRNA-155-5p Reduces Corneal Epithelial Permeability by Remodeling Epithelial Tight Junctions during Corneal Wound Healing

PURPOSE

Corneal epithelial cells play a vital role in the function of the cornea by forming a physical barrier to protect the eye from invasion by external pathogenic agents. A recent study showed that miR-155 promotes cutaneous wound healing. However, its function in corneal epithelial wound healing is unknown. The present study examined whether miR-155-5p reduces corneal epithelial permeability by remodeling epithelial tight junctions during corneal wound healing.

MATERIALS AND METHODS

Rat corneal wounds were produced by removing the central corneal epithelium with a blunt scalpel blade under a dissecting microscope. One eye of each rat was treated with topical miR-155-5p, and the other eye was treated with topical agomir negative control for 3 days before and after corneal epithelial wounding. Corneal epithelial permeability was assessed by the macromolecular osmosis method. Expression of zona occludens 1 (ZO-1), occludin, and myosin light chain kinase (MLCK) and phosphorylation of myosin light chain (MLC) were detected by Western blot. Human corneal epithelial (HCE) cells were cultured in the upper chamber of Transwell filters, and transepithelial electrical resistance (TER) was measured using a voltohmmeter. The distribution of ZO-1 and occludin in HCE cells treated with miR-155-5p was determined by immunofluorescence.

RESULTS

miR-155-5p significantly promoted the repair of corneal epithelial injury and reduced the permeability of the corneal epithelium. It significantly decreased expression of MLCK and phosphorylation of MLC and increased expression of the tight junction proteins ZO-1 and occludin in corneal epithelial cells during corneal wound healing. miR-155-5p significantly increased TER, decreased MLCK expression and MLC phosphorylation, increased ZO-1 and occludin expression, and promoted anchoring of tight junction proteins in the cell membrane and remodeling in HEC cells.

CONCLUSIONS

Our results suggest that miR-155-5p reduced corneal permeability and accelerated the recovery of corneal epithelial wounds by decreasing the expression of MLCK and phosphorylation of MLC and by remodeling tight junctions.

Acceleration of wound healing activity with syringic acid in streptozotocin induced diabetic rats

Impaired wound healing is a serious concern of uncontrolled hyperglycemia that can lead to gangrene, and even death. There is an urgent need to look for better alternative therapy because of the undesirable side effects of currently available synthetic drugs in the market. Syringic acid (SA) is a natural phenolic compound abundantly available in edible fruits and plants. In this study, wound healing activities of 2.5% and 5.0% SA were evaluated in type 2 diabetic rats using incisional wound model. SA-treated diabetic wounds showed faster rate of wound closure and epithelization with enhanced contents of hydroxyproline and protein compared to diabetic wounds. SA effectively prevents alterations in blood glucose levels, serum insulin and dyslipidemia in diabetic wound rats. The SA-treated diabetic wounds after 14 days of treatment demonstrated inhibition of pro-inflammatory response (NF-κB p65, TNF-α, IL-1β, IL-8 and IL-2) with improvement in anti-inflammatory response (IL-10), inhibited the elevated oxidative stress and decreased the concentrations of matrix metalloproteinases (MMP-2, -8 and -9) and increased the concentrations of TIMP-1 & TIMP- 2. Furthermore, the diabetic wounds were presented with an increase in expression of CD 31 and 68, growth factors (TGF-β1, collagen-I and α-SMA and VEGF) with significant improvement in collagen deposition, re-epithelialization and complete skin structure as revealed by histological analysis after treatment of diabetic wounds with SA for 14 days. Hence, the results of this study designate that SA significantly improves wound healing in diabetic rats and could be used as a potential therapy for treatment of diabetic wounds.

Basic concepts, current evidence, and future potential for gene therapy in managing cutaneous wounds

OBJECTIVE

Several studies have investigated the role of gene therapy in the healing process. The aim of this review is to explain the gene delivery systems in wound area.

RESULTS

Ninety-two studies were included and comprehensively overviewed. We described the importance of viral vectors such as adenoviruses, adeno-associated viruses, and retroviruses, and conventional non-viral vectors such as naked DNA injections, liposomes, gene gun, electroporation, and nanoparticles in achieving high-level expression of genes. Application of viral transfection, liposomal vectors, and electroporation were the main gene delivery systems. Genes encoding for growth factors or cytokines have been shown to result in a better wound closure in comparison to application of the synthetic growth factors. In addition, a combination of stem cell and gene therapy has been found an effective approach in regeneration of cutaneous wounds.

CONCLUSIONS

This article gives an overview of the methods and investigations applied on gene therapy in wound healing. However, clinical investigations need to be undertaken to gain a better understanding of gene delivery technologies and their roles in stimulating wound repair.

microRNA-155 inhibition restores Fibroblast Growth Factor 7 expression in diabetic skin and decreases wound inflammation

Treatment for chronic diabetic foot ulcers is limited by the inability to simultaneously address the excessive inflammation and impaired re-epithelization and remodeling. Impaired re-epithelization leads to significantly delayed wound closure and excessive inflammation causes tissue destruction, both enhancing wound pathogen colonization. Among many differentially expressed microRNAs, miR-155 is significantly upregulated and fibroblast growth factor 7 (FGF7) mRNA (target of miR-155) and protein are suppressed in diabetic skin, when compared to controls, leading us to hypothesize that topical miR-155 inhibition would improve diabetic wound healing by restoring FGF7 expression. In vitro inhibition of miR-155 increased human keratinocyte scratch closure and topical inhibition of miR-155 in vivo in wounds increased murine FGF7 protein expression and significantly enhanced diabetic wound healing. Moreover, we show that miR-155 inhibition leads to a reduction in wound inflammation, in accordance with known pro-inflammatory actions of miR-155. Our results demonstrate, for the first time, that topical miR-155 inhibition increases diabetic wound fibroblast growth factor 7 expression in diabetic wounds, which, in turn, increases re-epithelization and, consequently, accelerates wound closure. Topical miR-155 inhibition targets both excessive inflammation and impaired re-epithelization and remodeling, being a potentially new and effective treatment for chronic diabetic foot ulcers.

Adipose mesenchymal stem cell-derived exosomes promote cell proliferation, migration, and inhibit cell apoptosis via Wnt/β-catenin signaling in cutaneous wound healing

Cutaneous wounds, a type of soft tissue injury, are difficult to heal in aging. Differentiation, migration, proliferation, and apoptosis of skin cells are identified as key factors during wound healing processes. Mesenchymal stem cells have been documented as possible candidates for wound healing treatment because their use could augment the regenerative capacity of many tissues. However, the effects of exosomes derived from adipose-derived stem cell (ADSC-exos) on cutaneous wound healing remain to be carefully elucidated. In this present study, HaCaT cells were exposed to hydrogen peroxide (H₂ O ₂ ) for the establishment of the skin lesion model. Cell Counting Kit-8 assay, migration assay, and flow cytometry assay were conducted to detect the biological function of ADSC-exos in skin lesion model. Finally, the possible mechanism was further investigated using Western blot assay. The successful construction of the skin lesion model was confirmed by results of the enhanced cell apoptosis of HaCaT cells induced by H ₂ O ₂ , the increased Bax expression and decreased Bcl-2 expression. CD9 and CD63 expression evidenced the existence of ADSC-exos. The results of functional experiments demonstrated that ADSC-exos could prompt cell proliferation and migration of HaCaT cells, and repress cell apoptosis of HaCaT cells. In addition, the activation of Wnt/β-catenin signaling was confirmed by the enhanced expression of β-catenin at the protein level. Collectively, our findings suggest that ADSC-exos play a positive role in cutaneous wound healing possibly via Wnt/β-catenin signaling. Our study may provide new insights into the therapeutic target for cutaneous wound healing.

Retracted Article: MiR-132 enhances proliferation and migration of HaCaT cells by targeting TIMP3

MicroRNAs (miRNAs) are involved in multiple skin pathologies, including wound healing. Here, we explored the detailed role and molecular mechanism of miR-132 on HaCaT cells proliferation and migration. qRT-PCR assay was used to assess miR-132 expression and Western blot analysis was performed to detect inhibitor of matrix metalloproteinase-3 (TIMP3) level in HaCaT cells and normal human epidermal keratinocytes (NHEK) under transforming growth factor β1 (TGF-β1) treatment. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were employed to confirm the endogenous interaction between miR-132 and TIMP3. Cell proliferation ability was determined by MTT assay and the migration capacity was evaluated by transwell assay. TGF-β1 treatment resulted in a increase of miR-132 expression and a decrease of TIMP3 level in HaCaT cells and NHEK cells. The proliferation and migration abilities of TGF-β1-treated HaCaT cells were promoted by miR-132 upregulation, while them were inhibited by TIMP3 overexpression. Moreover, TIMP3 was a direct target of miR-132. MiR-132-mediated pro-proliferation and pro-migration effects were antagonized by TIMP3 in HaCaT cells under TGF-β1 treatment. Our data supported that miR-132 promoted the proliferation and migration of HaCaT cells at least partly by targeting TIMP3, highlighting miR-132 as a potential therapeutic strategy of wound healing.

MicroRNAs (miRNAs) are involved in multiple skin pathologies, including wound healing.

Aster koraiensis extract improves impaired skin wound healing during hyperglycemia

Background

Diabetes mellitus (DM) is one of the most common diseases found across the world. Aster koraiensis extract (AKE) has a protective effect on diabetic complications such as diabetic retinopathy. However, the effects of AKE on hyperglycemia-linked impairment of wound healing during DM have not been elucidated. In this study, we investigated the effects of AKE on delayed wound healing induced by DM.

Methods

DM was induced by intraperitoneal administration of streptozotocin (STZ; 75 mg/kg) to Sprague Dawley (SD) rats. Next, a wound was induced on the back of rats after administration of STZ. Further, AKE was prepared using an alcoholic extraction of A. koraiensis and orally administered daily for 18 days. Wound healing was evaluated using an in vitro migration assay and measuring the wound area in vivo. Skin tissue thickness was evaluated using hematoxylin and eosin staining. Matrix metalloprotease (MMP) activity and expression were detected using zymography and immunohistochemistry.

Results

AKE administration improved the delayed migration of keratinocytes in hyperglycemic animals. It also attenuated an increase in keratinocyte MMP-2/9 activity induced by hyperglycemia. AKE protected against DM-induced impaired wound healing in rats and prevented the degradation of skin tissue induced by DM. In addition, AKE attenuated DM-induced increase in MMP-2/9 expression in skin tissue.

Conclusions

In conclusion, AKE may promote wound healing by re-epithelization via promotion of keratinocyte migration and by attenuating the disruption of the skin tissue layer via MMP-2/9 inhibition during hyperglycemia.

Processed eggshell membrane powder regulates cellular functions and increase MMP-activity important in early wound healing processes

Avian eggshell membrane (ESM) is a natural biomaterial that has been used as an alternative natural bandage to cure wounds, and is available in large quantities from egg industries. We have previously demonstrated that processed eggshell membrane powder (PEP), aiming to be used in a low cost wound healing product, possesses anti-inflammatory properties. In this study, we further investigated effects of PEP on MMP activities in vitro (a dermal fibroblast cell culture system) and in vivo (a mouse skin wound healing model). Three days incubation with PEP in cell culture led to rearrangement of the actin-cytoskeleton and vinculin in focal adhesions and increased syndecan-4 shedding. In addition, we observed increased matrix metalloproteinase type 2 (MMP-2) enzyme activation, without effects on protein levels of MMP-2 or its regulators (membrane type 1 (MT1)-MMP and tissue inhibitor of matrix metalloproteinase type 2 (TIMP-2). Longer incubation (10 days) led to increased protein levels of MMP-2 and its regulators. We also observed an increased alpha-smooth muscle actin (α-SMA) production, suggesting an effect of PEP on myofibroblast differentiation. In vivo, using the mouse skin wound healing model, PEP treatment (3 days) increased MMP activity at the wound edges, along with increased MMP-2 and MMP-9 protein levels, and increased keratinocyte cell proliferation. Altogether, our data suggest PEP stimulates MMP activity, and with a positive effect on early cellular events during wound healing.

Expression of MMP-2 and TIMP-3 with incidence and prognosis of giant-cell tumor of the bone

The expression of matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of matrix metalloproteinase-3 (TIMP-3) in giant-cell tumor of bone (GCT), and the correlation of their expression with the clinicopathologic features and prognosis were investigated. A total of 70 GCT patients treated in our hospital from September, 2013 to September, 2015, were selected, and the tumor and para-carcinoma tissues were obtained by surgery. The expression levels of MMP-2 and TIMP-3 in GCT and para-carcinoma tissues were detected via semi-quantitative polymerase chain reaction (PCR) and western blot analysis, as well as immunohistochemical staining. Moreover, the clinicopathological data of the GCT patients were collected to study the correlation of MMP-2 and TIMP-3 with clinicopathological features and prognosis of GCT. The results of semi-quantitative PCR and western blot analysis revealed that the expression level of MMP-2 in tissues of the 70 GCT patients was significantly higher than that in para-carcinoma tissues, and the difference was statistically significant (P<0.01), while the expression level of TIMP-3 was obviously lower than that in para-carcinoma tissues (P<0.01). The results of immunohistochemical staining revealed that the positive expression rate of MMP-2 was 57.6% in GCT tissues and 18.9% in para-carcinoma tissues, while that of TIMP-3 was 63.2% in GCT tissues and 13.8% in para-carcinoma tissues, and the differences were statistically significant (P<0.01). The expression levels of MMP-2 and TIMP-3 were correlated with the diameter of tumor, clinical staging, lymph node metastasis and relapse of GCT (P<0.01), but were not correlated with the age and sex of GCT patients (P>0.05). There was a negative correlation between MMP-2 and TIMP-3 expression levels (r=−0.258, P<0.05). The expression levels of MMP-2 and TIMP-3 are closely related to the clinicopathological features and prognosis of patients, which can be used as one of the clinical examination indexes of GCT and also provide new insights for the clinical treatment of GCT.

Effects of CD100 promote wound healing in diabetic mice

Diabetes is a condition that causes delayed wound healing and results in chronic wounds. CD100 has been reported to promote and induce potent and obvious angiogenesis both in vivo and in vitro studies, the absence of which are a main cause of the diabetic chronic wound. In the present study, we investigated the effects of application of soluble CD100 on wound healing in diabetic mice. Four 5-mm full-thickness dermal wounds were made on each male db/db mouse. 12 mice from CD100 group were subcutaneously injected with 250 ng of CD100 (50 µl) per wound, in addition, 12 mice were injected with the same volume phosphate-balanced solution as the control. The animals were treated every other day until the wounds healed completely. Images were obtained to calculate the area ratio of the original area. HE and Masson's trichrome staining were used for histological examination. Collagen remodeling, angiogenesis and wound bed inflammation were evaluated by immunohistochemical staining and western blot. We demonstrated that CD100 had distinct functions during the wound healing process. Histological and western blotting analysis showed a more organized epithelium and dermis, more collagen fibers, higher angiogenesis and lower inflammation in the CD100 group than in the PBS group. These findings suggest that CD100 may accelerate wound healing in diabetic mice by promoting angiogenesis in the wound and by reducing the inflammatory response.

Insights into the key roles of epigenetics in matrix macromolecules-associated wound healing

Extracellular matrix (ECM) is a dynamic network of macromolecules, playing a regulatory role in cell functions, tissue regeneration and remodeling. Wound healing is a tissue repair process necessary for the maintenance of the functionality of tissues and organs. This highly orchestrated process is divided into four temporally overlapping phases, including hemostasis, inflammation, proliferation and tissue remodeling. The dynamic interplay between ECM and resident cells exerts its critical role in many aspects of wound healing, including cell proliferation, migration, differentiation, survival, matrix degradation and biosynthesis. Several epigenetic regulatory factors, such as the endogenous non-coding microRNAs (miRNAs), are the drivers of the wound healing response. microRNAs have pivotal roles in regulating ECM composition during wound healing and dermal regeneration. Their expression is associated with the distinct phases of wound healing and they serve as target biomarkers and targets for systematic regulation of wound repair. In this article we critically present the importance of epigenetics with particular emphasis on miRNAs regulating ECM components (i.e. glycoproteins, proteoglycans and matrix proteases) that are key players in wound healing. The clinical relevance of miRNA targeting as well as the delivery strategies designed for clinical applications are also presented and discussed.

Lumican as a multivalent effector in wound healing

Wound healing, a complex physiological process, is responsible for tissue repair after exposure to destructive stimuli, without resulting in complete functional regeneration. Injuries can be stromal or epithelial, and most cases of wound repair have been studied in the skin and cornea. Lumican, a small leucine-rich proteoglycan, is expressed in the extracellular matrices of several tissues, such as the cornea, cartilage, and skin. This molecule has been shown to regulate collagen fibrillogenesis, keratinocyte phenotypes, and corneal transparency modulation. Lumican is also involved in the extravasation of inflammatory cells and angiogenesis, which are both critical in stromal wound healing. Lumican is the only member of the small leucine-rich proteoglycan family expressed by the epithelia during wound healing. This review summarizes the importance of lumican in wound healing and potential methods of lumican drug delivery to target wound repair are discussed. The involvement of lumican in corneal wound healing is described based on in vitro and in vivo models, with critical emphasis on its underlying mechanisms of action. Similarly, the expression and role of lumican in the healing of other tissues are presented, with emphasis on skin wound healing. Overall, lumican promotes normal wound repair and broadens new therapeutic perspectives for impaired wound healing.

Acute downregulation of miR-155 leads to a reduced collagen synthesis through attenuating macrophages inflammatory factor secretion by targeting SHIP1

Fibrosis, tightly associated with fibroblasts collagen synthesis, is related closely with inflammatory response. Our previously study found that acute downregulation of miR-155 at wound sites leads to a reduced fibrosis, however its particular mechanism is unclear. Herein, we aimed to explore the mechanism of miR-155 in reducing fibrosis. We first found that down-regulation of miR-155 inhibited macrophages transforming growth factor-β1 (TGF-β1) and IL-1β secretion. Next, we found that co-cultured with macrophages increased the proliferation and collagen synthesis of fibroblasts, and downregulation of miR-155 in macrophages could effectively attenuate the accelerative effects. We further identified SH2 domain containing inositol-5-phosphatase 1 (SHIP1) as a direct target of miR-155 in macrophages, and the expression of SHIP1 was negatively correlated with the level of miR-155. We further confirmed that PI3K/Akt pathway was involved in this process. Last, we found that downregulation of miR-155 leads to a reduced fibrosis in sever burn rat. Taken together, these results indicate that down-regulation of miR-155 leads to a reduced fibroblasts proliferation and collagen synthesis through attenuating macrophages TGF-β1 and IL-1β secretion by targeting SHIP1 via PI3K/Akt pathway, suggesting its potential therapeutic effects on the treatment of skin fibrosis.

Monocyte-derived tissue transglutaminase in multiple sclerosis patients: reflecting an anti-inflammatory status and function of the cells?

BACKGROUND

Leukocyte infiltration into the central nervous system is an important feature of multiple sclerosis (MS) pathology. Among the infiltrating cells, monocytes comprise the largest population and are considered to play a dual role in the course of the disease. The enzyme tissue transglutaminase (TG2), produced by monocytes, plays a central role in monocyte adhesion/migration in animal models of MS. In the present study, we questioned whether TG2 expression is altered in monocytes from MS patients compared to healthy control (HC) subjects. Moreover, we determined the inflammatory status of these TG2-expressing monocytes, what inflammatory factor regulates TG2 expression, and whether TG2 can functionally contribute to their adhesion/migration processes.

METHODS

Primary human monocytes from MS patients and HC subjects were collected, RNA isolated and subjected to qPCR analysis. Human THP-1 monocytes were lentivirally transduced with TG2 siRNA or control and treated with various cytokines. Subsequently, mRNA levels of inflammatory factors, adhesion properties, and activity of RhoA were analyzed in interleukin (IL)-4-treated monocytes.

RESULTS

TG2 mRNA levels are significantly increased in monocytes derived from MS patients compared to HC subjects. In addition, correlation analyses indicated that TG2-expressing cells display a more anti-inflammatory, migratory profile in MS patients. Using THP-1 monocytes, we observed that IL-4 is a major trigger of TG2 expression in these cells. Furthermore, knockdown of TG2 expression leads to a pro-inflammatory profile and reduced adhesion/migration properties of IL-4-treated monocytes.

CONCLUSIONS

TG2-expressing monocytes in MS patients have a more anti-inflammatory profile. Furthermore, TG2 mediates IL-4-induced anti-inflammatory status in THP-1 monocytes, adhesion, and cytoskeletal rearrangement in vitro. We thus propose that IL-4 upregulates TG2 expression in monocytes of MS patients, driving them into an anti-inflammatory status.