Human Wound Research Articles

Thermosensitive hydrogel coupled with sodium ascorbyl phosphate promotes human umbilical cord-derived mesenchymal stem cell-mediated skin wound healing in mice.

Poor survival and restricted function of transplanted stem cells are regarded as limiting their efficacy in wound recovery greatly. Consequently, it is necessary to identify innovative therapeutic strategies to solve these issues. Firstly, the biological effect of PF-127 hydrogel alone and in combination with SAP on the survival, and migration of cultured HUCMSCs was assessed by cell viability, apoptosis, and scratch wound assays. S. aureus and E. coli were used to evaluate the antibacterial activity of PF-127 plus SAP combination. Further, the ability of HUCMSCs-conditioned medium (HUCMSCs-CM) to promote the angiogenesis and migration of human umbilical vein endothelial cells (HUVECs) in vitro was evaluated using tube formation and transwell migration assays. Finally, the HUCMSCs embedded in PF-127 plus SAP scaffold were administered onto mice's excisional cutaneous wound bed. Histological and immunohistochemical analyses were employed to investigate the wound healing capacity as well as cellular responses of PF-127/HUCMSCs/SAP hydrogel. PF-127 showed cytotoxicity on HUCMSCs, whereas the addition of SAP significantly promoted cell viability and alleviated apoptosis of HUCMSCs encapsulated in PF-127 hydrogel in vitro. SAP supplementation substantially abrogated the inhibiting effect of PF-127 on the migration of HUCMSCs in vitro. The combination of PF-127 and SAP exerted an obvious bacteriostatic function on S. aureus and E. coli. Moreover, the co-treatment with SAP could remarkably enhance the stimulative effect of HUCMSCs-CM on the angiogenesis and migration of HUVECs in vitro. PF-127 combined SAP-embedded HUCMSCs transplantation resulted in a potently accelerated wound healing process, promoted the number of proliferating cells and newly formed blood vessels, as well as enhanced expression of vascular endothelial growth factor. PF-127 coupled with SAP contributes to HUCMSCs-mediated traumatic wound closure in mice by promoting cell survival, antibacterial action, and angiogenesis. Our results offered a theoretical foundation for the clinical treatment of traumatic skin defects.

Fluorescent biosensor based on MB-APT combined with Pt NPs for the detection of infectious bacteria in mouse and human wounds

Bacterial infection of wounds is one of great concern to patients, and rapid and correct detection of bacterial infection is crucial to ensure accurate diagnosis and early intervention. Based on the principle that glucose can only be consumed by live bacteria, a fluorescent biosensor was constructed to detect four kinds of common infectious bacteria (Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus) in skin wounds, taking advantage of magnetic bead-aptamer for recognizing, sorting and enrichment, platinum nanoparticles for signal amplification. The linear detection range of AB, EC, PA and SA were 27– 8 × 106 CFU/mL, 10– 2.5 × 107 CFU/mL, 34– 2.5 × 107 CFU/mL and 10– 1.0 × 107 CFU/mL, respectively, and the limits of detection were 27 CFU/mL, 10 CFU/mL, 34 CFU/mL and 2 CFU/mL. Furthermore, all target bacteria in samples containing 8 × 108 CFU/mL of other interfering bacteria have been successfully identified and quantified. The proposed method was also successfully applied to the detection of bacterial infection in skin wounds of mouse and human, including the detection of separate bacterial infection as well as a coinfection. The recovery of this method was in the range of 90.161– 109.961%. Thus, this proposed method can be a promising candidate for rapid and convenient evaluation of infectious bacteria in point-of-care settings.

Color changing Redox Active Paper Stamps (CoRAPS) for quick and easy detection of bacterial infection

Even small wounds can pose severe health risks to the subject on being infected with bacterial pathogens. Added concern about this comes from the fact that such infections might not be identifiable with normal eyes without any assistance. Therefore, the detection of such infections is of utmost importance. In the current study, color changing redox-active paper stamps (CoRAPS) have been developed to detect such microbial infections in a quick span with low required skill set and less complex machinery. CoRAPS utilizes the combination of carbon nanoparticles (CNPs) and a redox-active dye, resazurin, on a paper substrate. The prepared CoRAPS were found to be capable of detecting the bacterial population within 15 min of exposure in suspension condition whereas artificially created wound mimic with bacterial load could show color change of CoRAPS in ∼40 min of exposure. These timelines are significantly lower than the time required for conventional methods which generally takes 12–24 h in accessing the infection. The sensitivity of the product could be enhanced ∼100-fold by using an associated, newly developed, Bacticator app. Thus, CoRAPS in combination of newly developed Bacticator app provides a potential solution for the quick, user-friendly, and on-site detection of bacterial infection and can be effectively used for human and animal wound infection detections alike.

Formulation Development and Evaluation of New Polyherbal Gel Formulations for Their Wound Healing Activity in Rat

Synoptic studies on natural products have been conducted as a result of the lack of a potential remedy and associated flaw in allopathic medicines, as these items have been found to be less harmful and more affordable. The identification and assessment of therapeutic potential in pharmaceuticals led to the development of novel, affordable medications for the treatment of a variety of ailments, including chronic wounds. To determine if plant extracts can effectively cure wounds, in-vitro cell scratch testing is a practical and affordable method. Traditional herbal remedies for treating wounds include Azadirachta indica (A. indica) and Aloe barbadensis miller (Aloe vera, A. vera). The goal of the current study was to assess the ability of a polyherbal formulation (A. vera and A. indica) to promote wound healing in Wistar albino rats utilising excision, incision, and dead space wound models. A. vera and A. indica extracts were used in varied concentrations to create formulations PHF1 through PHF5. Utilising criteria like physical appearance, pH, extrudability, viscosity, spreadability, homogeneity, grittiness, and stability study, the generated polyherbal gel formulation was assessed. On days 3, 6, 9, 12, 15 and 21, as well as day 24, wound healing was observed along with the percentage of wound contraction, epithelialization period, hydroxyproline content, tensile strength, granuloma weight, and protein content (dead space wound models). In an excision wound model, polyherbal gel PHF4 demonstrated percent wound contraction in 12 days, and Groups II and IV saw considerably (P 0.01) shorter epithelialization times. In incision wound models, the animal group treated with polyherbal gel PHF4 demonstrated significantly higher levels of hydroxyproline than all other formulations as well as significantly higher tensile strength. PHF4 demonstrated the best efficacy in dead space wound models compared to other extracts and was significantly different from the treatment group in terms of granuloma weight and protein content. It can be said that poly herbal formulations have wound healing properties, possibly as a result of their epithelization, supporting the traditional assertion that they can be used to treat many human wound types.

Ciprofloxacin-Loaded Polyvinylpyrrolidone Foils for the Topical Treatment of Wound Infections with Methicillin-Resistant Staphylococcus aureus (MRSA).

Bacterial infections are a constant challenge in the management of acute and chronic wounds. Chronic wounds, such as diabetic foot ulcers, have increased significantly in the last few years due to the rise of an aging population. A better understanding of the infectious pathophysiological mechanisms is urgently needed along with new options for the treatment of wound infections and wound-healing disorders. New advances in the preparation of biocompatible dressing materials that can be loaded with antimicrobial drugs may improve the topical treatment of infected wounds. In this study, we investigated the antimicrobial activity of polyvinylpyrrolidone (PVP) foils loaded with ciprofloxacin (Cipro-foils) in the presence of acetic acid as a co-solvent. We used ex vivo human wounds that were infected with two bacterial strains: methicillin-resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa (PAO1). The effectiveness of the treatment was demonstrated by the quantification of the living bacteria extracted from the wound and the detection of released immunological mediators in skin extracts and in the skin culture media. We found that Cipro-foils effectively treated the infection with both PAO1 and MRSA. Other than PAO1, MRSA had no lytic activity toward skin proteins. MRSA infections increased cytokines' expression and release. Interestingly, treatment with Cipro-foils could partially counteract these effects.

Impact of human wound exudate on the bactericidal efficacy of commercial antiseptic products.

By default, the antimicrobial efficacy of antiseptics used in wound management is tested in vitro under standardised conditions according to European standard DIN EN 13727, with albumin and sheep erythrocytes used as organic challenge. However, it is not clear whether these testing conditions adequately reflect the wound bed environment and its interaction with antiseptic products intended to be used in wounds in humans. This study compared the efficacy of different commercial antiseptic products based on octenidine dihydrochloride (OCT), polyhexamethylene biguanide (PHMB) and povidone-iodine under challenge with human wound exudate collected from the hard-to-heal wounds of patients, compared to the standardised organic load, in an in vitro setting according to DIN EN 13727. The bactericidal efficacy of the tested products was reduced to a different extent when challenged with human wound exudate, compared to the standardised conditions. Overall, OCT-based products showed the necessary germ count reductions at the shortest exposure times (e.g., 15 seconds for Octenisept (Schülke & Mayr GmbH, Germany)). PHMB-based products were the least efficient. In addition to the protein content, other components of wound exudate, such as the microbiota, seem to influence the efficacy of antiseptics. This study demonstrated that the standardised in vitro test conditions may only partially reflect actual wound bed conditions in humans.

Human skin biofilm model: translational impact on swabbing and debridement

Objective: Wound biofilms are one of the greatest challenges in the therapy of hard-to-heal (chronic) wounds, as potent antimicrobial substances fail to eradicate bacteria within short incubation periods. Preclinical investigations using novel model systems that closely mimic the human wound environment and wound biofilm are required to identify new and effective therapeutic options. This study aims to identify bacterial colonisation patterns that are relevant for diagnosis and therapy. Method: In this study, a recently established human plasma biofilm model (hpBIOM) was incorporated into a wound within human dermal resectates after abdominoplasty. The interaction of the biofilm-forming bacteria meticillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa with the skin cells was investigated. Possible effects on wound healing processes in correlation with the persistence of the biofilm in the wound environment were analysed in patients with leg ulcers of different aetiologies and biofilm burden. Results: Using haematoxylin and eosin staining, species-dependent infiltration modes of the bacteria into the wound tissue were determined for the pathogens MRSA and Pseudomonas aeruginosa. The spreading behaviour correlated with clinical observations of the spatial distributions of the bacteria. In particular, the clinically prominent Pseudomonas aeruginosa-specific distension of the wound margin was identified as epidermolysis due to persistent infiltration. Conclusion: The hpBIOM applied in this study represents a potential tool for preclinical analyses dealing with approval processes for new antimicrobial applications. In terms of clinical practice, a microbiological swabbing technique including the wound margin should be routinely applied to prevent wound exacerbation.

Utilization of coffee pulp for the production of sustainable cellulosic composite and plant-based hydrogel as a potential human wound dressing

Utilization of coffee pulp for the production of sustainable cellulosic composite and plant-based hydrogel as a potential human wound dressing

LONEPINELLA SP. ISOLATED FROM WOUND INFECTIONS OF KOALAS.

We describe two cases of wound infections of koalas (Phascolarctos cinereus), one wild and one captive, in which Lonepinella-like organisms were involved. The wild adult koala was captured with bite wound injuries, as part of a koala population management program in Queensland, Australia. In both cases, there was evidence of physical trauma causing the initial wound. The captive koala suffered injury from the cage wire, and the wild koala had injuries suggestive of intermale fighting. Gram-negative bacteria isolated from both cases proved to be challenging to identify using routine diagnostic tests. The wound in the captive koala yielded a pure culture of an organism shown by whole genome sequence (WGS) analysis to be a member of the genus Lonepinella, but not a member of the only formally described species, L. koalarum. The wound of the wild koala yielded a mixed culture of Citrobacter koseri, Enterobacter cloacae and an organism shown by WGS analysis to be Lonepinella, but again not Lonepinella koalarum. Both cases were difficult to treat; the captive koala eventually had to have the phalanges amputated, and the wild koala required removal of the affected claw. The two Lonepinella isolates from these cases have a close relationship to an isolate from a human wound caused by a koala bite and may represent a novel species within the genus Lonepinella. Wound infections in koalas linked to Lonepinella have not been reported previously. Wildlife veterinarians need to be aware of the potential presence of Lonepinella-like organisms when dealing with wound infections in koalas, and the inability of commercial kits and systems to correctly identify the isolates.

Presentation and treatment of animal and human bite injuries at a Swiss tertiary emergency department: a cross-sectional study.

Animal and human bite injuries are a relevant health problem worldwide. With the increasing number of pets, bite injuries are becoming more frequent. Previous studies on animal and human bite injuries in Switzerland were completed several years ago. The aim of the present study was to provide a detailed overview of patients with bite injuries admitted to a tertiary emergency department in Switzerland in terms of demographics, injury patterns and treatment strategies. A 9-year cross-sectional analysis of patients presenting to the emergency department of Bern University Hospital in the period January 2013 to December 2021 following an animal or human bite injury. A total of 829 patients with bite injuries were identified, including 70 for postexposure prophylaxis only. Their median age was 39 (IQR 27-54) years and 53.6% were female. Most patients were bitten by a dog (44.3%), followed by cats (31.5%) and humans (15.2%). Most bite injuries were mild (80.2%); severe injuries were mainly found in dog bites (28.3%). Most patients were treated within six hours after human (80.9%) or dog (61.6%) bites; after cat bites, patients often presented with a delay (74.5%) and signs of infection (73.6%). Human bite wounds were superficial in the majority of cases (95.7%), rarely showed signs of infection (5.2%) at the time of presentation and hospitalisation was never required. Our study provides a detailed overview of patients admitted to an emergency department of a tertiary Swiss University Hospital after an animal or human bite. In summary, bite injuries are common among patients who present to the emergency department. Therefore, primary and emergency care clinicians should be familiar with these injuries and their treatment strategies. The high risk of infection, particularly in cat bites, may warrant surgical debridement in the initial treatment of these patients. Prophylactic antibiotic therapy and close follow-up examinations are recommended in most cases.

29-OR: Diabetic Wound Keratinocytes Induce Macrophage JMJD3–Mediated Nlrp3 Expression

Macrophage (Mφ) plasticity is critical for normal wound repair; however, type 2 diabetic (T2D) wound Mφs display a delayed chronic inflammatory state that prevents the resolution of wound inflammation. Increased NLRP3 inflammasome gene expression and activation in Mφs contributes to impaired wound healing in T2D and is induced by diabetic wound environment factors, yet the molecular mechanisms regulating this are unclear. Our lab has shown that keratinocytes, structural cells in the skin, regulate skin inflammation and Mφ phenotype during wound healing by preferentially producing proinflammatory cytokines. Thus, this project explores the molecular mechanisms by which keratinocytes drive increased Nlrp3 expression in diabetic wound Mφs. Here, we found that Nlrp3 expression is increased in diabetic wound Mφs late post-injury, and this can be induced by stimulation of normal wound Mφs with diabetic wound keratinocyte supernatant. Further, we found that stimulation of Mφs with diabetic wound keratinocyte supernatant resulted in decreased H3K27me3 deposition at the Nlrp3 promoter. Using genetically engineered mice (Jmjd3 fl/fl lyz2cre), we demonstrate that JMJD3, a demethylase specific for H3K27, controls Mφ-mediated Nlrp3 expression and inflammasome activation during wound healing. Importantly, we show that diabetic wound keratinocytes induce Jmjd3 expression in Mφs via IL1 receptor and MyD88 upstream signaling. Interestingly, we found that IL1α is increased in human and murine wound diabetic keratinocytes compared to nondiabetic controls and stimulation of Mφs with IL1α increases Nlrp3 expression via a H3K27me3/JMJD3-mediated mechanism. Thus, our data suggest a role for keratinocyte IL1α in driving increased Nlrp3 expression in chronic diabetic wound Mφs via JMJD3. Continued investigation into the dysregulation of the keratinocyte-Mφ axis in diabetic wounds is key to developing novel treatments for non-healing wounds in T2D patients. Disclosure S. Wolf-Fortune: None. J. Moon: None. A. Joshi: None. P. Mazumder: None. E. Barrett: None. K.D. Mangum: None. K. Gallagher: None. Funding National Institutes of Health (1K99DK133828-01, P30DK089503, R01HL137919, R01DK124290, R01HL15627401, R01DK127531)

E-cadherin and aquaporin-3 are downregulated in wound edges of human chronic wounds.

Chronic wounds are defined as wounds that fail to proceed through the normal phases of wound healing; a complex process involving different dynamic events including migration of keratinocytes in the epidermis. Chronic wounds are estimated to affect 1-2% of the human population worldwide and are a major socioeconomic burden. The prevalence of chronic wounds is expected to increase with the rising number of elderly and patients with diabetes and obesity, who are at high risk of developing chronic wounds. Since E-cadherin and the water channel aquaporin-3 are important for both skin function and cell migration, and aquaporin-3 is furthermore involved in wound healing of the skin demonstrated by impaired wound healing in aquaporin-3-null mice, we hypothesized that E-cadherin and aquaporin-3 expression may be dysregulated in chronic wounds. Therefore, we investigated the expression of E-cadherin and aquaporin-3 in biopsies from the edges of chronic wounds from human patients. This was accomplished by immunohistochemical stainings of E-cadherin and aquaporin-3 on serial sections followed by qualitative evaluation of staining patterns, which revealed low expression of both E-cadherin and aquaporin-3 at the wound edge. Future studies are needed to reveal if this downregulation is associated with the pathophysiology of chronic wounds.

Catechin, epicatechin, curcumin, garlic, pomegranate peel and neem extracts of Indian origin showed enhanced anti-inflammatory potential in human primary acute and chronic wound derived fibroblasts by decreasing TGF-β and TNF-α expression

BackgroundAlthough chronic wounds are devastating and can cause burden at multiple levels, chronic wound research is still far behind. Chronic wound treatment is often less efficient due to delay in diagnosis and treatment, non-specific treatment mainly due to lack of knowledge of wound healing or healing resistance genes. It’s known that chronic wounds do not progress towards healing, because it gets stalled in inflammatory phase of wound healing.ObjectiveWe aimed to use phytoextracts possessing excellent anti-inflammatory properties to regulate the unbalanced levels of cytokines responsible for increased inflammation.MethodsEvaluation of anti-inflammatory activity of selected phytoextracts namely, Camellia sinensis (L.) Kuntze, Acacia catechu (L.f) Willd., Curcuma longa (L.), Allium sativum (L.), Punica granatum (L.) and Azadirachta indica A. hereafter, called as catechin, epicatechin, curcumin, garlic, pomegranate and neem extracts, respectively in Acute wound fibroblasts (AWFs) and Chronic wound fibroblasts (CWFs) using flow cytometry.ResultsThe phytoextracts exhibited no cytotoxicity below 100 μg/ml on normal Human Dermal fibroblasts (HDFs), while garlic extract showed highest cell viability followed by catechin, epicatechin, curcumin, pomegranate peel and neem based on IC50 value. Garlic, catechin and epicatechin extracts showed highest anti-inflammatory activities for both TGF-β and TNF-α in both AWFs and CWFs treated cells. After treatment of AWFs with catechin, epicatechin and garlic extracts, TGF-β and TNF-α expression was significantly reduced compared to untreated AWFs and reached to almost normal HDFs level. Also, after treatment of CWFs with catechin, epicatechin and garlic extracts, TGF-β and TNF-α expression was significantly reduced compared to untreated CWFs and was lesser than untreated AWFs.ConclusionThe present findings reveal the potential of catechin, epicatechin and garlic extracts for the treatment of acute and chronic wounds with excellent anti-inflammatory properties.

Evaluation in a porcine wound model and long-term clinical assessment of an autologous heterogeneous skin construct used to close full-thickness wounds

Acute and chronic wounds involving deeper layers of the skin are often not adequately healed by dressings alone and require therapies such as skin grafting, skin substitutes, or growth factors. Here we report the development of an autologous heterogeneous skin construct (AHSC) that aids wound closure. AHSC is manufactured from a piece of healthy full-thickness skin. The manufacturing process creates multicellular segments, which contain endogenous skin cell populations present within hair follicles. These segments are physically optimized for engraftment within the wound bed. The ability of AHSC to facilitate closure of full thickness wounds of the skin was evaluated in a swine model and clinically in 4 patients with wounds of different etiologies. Transcriptional analysis demonstrated high concordance of gene expression between AHSC and native tissues for extracellular matrix and stem cell gene expression panels. Swine wounds demonstrated complete wound epithelialization and mature stable skin by 4 months, with hair follicle development in AHSC-treated wounds evident by 15 weeks. Biomechanical, histomorphological, and compositional analysis of the resultant swine and human skin wound biopsies demonstrated the presence of epidermal and dermal architecture with follicular and glandular structures that are similar to native skin. These data suggest that treatment with AHSC can facilitate wound closure.

First person – Harry Scott

ABSTRACT First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping researchers promote themselves alongside their papers. Harry Scott is first author on ‘ The human discs large protein 1 interacts with and maintains connexin 43 at the plasma membrane in keratinocytes’, published in JCS. Harry is a PhD student in the labs of Professor Sheila Graham and Patricia Martin at University of Glasgow and Glasgow Caledonian University, UK, where he studies the role of Cx43 and Dlg1 in human papillomavirus-associated cancer and wound healing.

Antibacterial and Cytotoxic Activity of Mentha arvensis L. Leaves Methanolic Extract In vitro

Treatment with herbal drugs is considered one of the oldest and safest methods for treating various diseases. Mentha arvensis is a medicinal plant used worldwide in the pharmaceutical industry for its antibacterial, anticancer, antiallergic, and anti-inflammatory properties. In the present study, the antibacterial activity of the methanolic extract of M. arvensis leaves was tested at different concentrations (50, 100, 150, and 200 µg/ml) against bacteria isolated from human burn wound infections, including Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus. The results demonstrated that at concentrations of 100, 150, and 200 µg/ml, the methanolic extract exhibited strong antibacterial activity against S. aureus and P. aeruginosa, while K. pneumoniae isolates were resistant to the extract at all tested concentrations. Further, the cytotoxic activity of the methanolic extract was assessed at various concentrations (100, 140, 160, 180, 220, and 250 µg/ml) against two cell lines: the RD tumor cell line and Vero normal cell line. The higher concentrations of the extract (220 and 250 µg/ml) showed potent cytotoxic effects on the RD cell line after 72 hours in a dose- and time-dependent manner. In contrast, the extract exhibited lower cytotoxic effects on Vero cells at the same concentrations after 72 h.

Extended characterization of IL-33/ST2 as a predictor for wound age determination in skin wound tissue samples of humans and mice.

Interleukin (IL)-33, an important inflammatory cytokine, is highly expressed in skin wound tissue and serum of humans and mice, and plays an essential role in the process of skin wound healing (SWH) dependent on the IL-33/suppression of tumorigenicity 2 (ST2) pathway. However, whether IL-33 and ST2 themselves, as well as their interaction, can be applied for skin wound age determination in forensic practice remains incompletely characterized. Human skin samples with injured intervals of a few minutes to 24 hours (hs) and mouse skin samples with injured intervals of 1 h to 14 days (ds) were collected. Herein, the results demonstrated that IL-33 and ST2 are increased in the human skin wounds, and that in mice skin wounds, there is an increase over time, with IL-33 expression peaking at 24 hs and 10 ds, and ST2 expression peaking at 12 hs and 7 ds. Notably, the relative quantity of IL-33 and ST2 proteins < 0.35 suggested a wound age of 3 hs; their relative quantity > 1.0 suggested a wound age of 24 hs post-mouse skin wounds. In addition, immunofluorescent staining results showed that IL-33 and ST2 were consistently expressed in the cytoplasm of F4/80-positive macrophages and CD31-positive vascular endothelial cells with or without skin wounds, whereas nuclear localization of IL-33 was absent in α-SMA-positive myofibroblasts with skin wounds. Interestingly, IL-33 administration facilitated the wound area closure by increasing the proliferation of cytokeratin (K) 14 -positive keratinocytes and vimentin-positive fibroblasts. In contrast, treating with its antagonist (i.e., anti-IL-33) or receptor antagonist (e.g., anti-ST2) exacerbated the aforementioned pathological changes. Moreover, treatment with IL-33 combined with anti-IL-33 or anti-ST2 reversed the effect of IL-33 on facilitating skin wound closure, suggesting that IL-33 administration facilitated skin wound closure through the IL-33/ST2 signaling pathway. Collectively, these findings indicate that the detection of IL-33/ST2 might be a reliable biomarker for the determination of skin wound age in forensic practice.

A Pseudomonas aeruginosa small RNA regulates chronic and acute infection

The ability to switch between different lifestyles allows bacterial pathogens to thrive in diverse ecological niches1,2. However, a molecular understanding of their lifestyle changes within the human host is lacking. Here, by directly examining bacterial gene expression in human-derived samples, we discover a gene that orchestrates the transition between chronic and acute infection in the opportunistic pathogen Pseudomonas aeruginosa. The expression level of this gene, here named sicX, is the highest of the P. aeruginosa genes expressed in human chronic wound and cystic fibrosis infections, but it is expressed at extremely low levels during standard laboratory growth. We show that sicX encodes a small RNA that is strongly induced by low-oxygen conditions and post-transcriptionally regulates anaerobic ubiquinone biosynthesis. Deletion of sicX causes P. aeruginosa to switch from a chronic to an acute lifestyle in multiple mammalian models of infection. Notably, sicX is also a biomarker for this chronic-to-acute transition, as it is the most downregulated gene when a chronic infection is dispersed to cause acute septicaemia. This work solves a decades-old question regarding the molecular basis underlying the chronic-to-acute switch in P. aeruginosa and suggests oxygen as a primary environmental driver of acute lethality.

Retracted: Development of Training Videos Based on Virtual Reality Side-Cut High-Simulation Simulator of Human Wound Technology and Sealed Sputum Suction.

[This retracts the article DOI: 10.1155/2021/9985041.].

Histone Demethylase JARID1C/KDM5C Regulates Th17 T Cells in Diabetic Wounds by Increasing IL-6 Expression in Plasmacytoid Dendritic Cells

Plasmacytoid dendritic cells (pDCs) are first responders to tissue damage and interact with wound CD4 T cells to orchestrate tissue repair. In diabetes, the role of pDCs and their subsequent influence on wound CD4+ T cells and inflammation during tissue repair is unknown. Using human diabetic wound single cell sequencing, we identified that human wound CD4+ T-cells are primarily of the inflammatory TH17 phenotype. Thus, we hypothesized that pDCs in the wounds may regulate this T-cell phenotype, contributing to chronic inflammation. We utilized human diabetic wound single cell sequencing and analyzed murine wounds from diabetic and nondiabetic mice. These tissue were subjected to pDC isolation by magnetic sorting, flow cytometry, chromatin immunoprecipitation, quantitative polymerase chain reaction, histone arrays, and enzyme-linked immunosorbent assays. We found that diabetic pDC produced significantly more IL-6 compared to controls. This is important as IL-6 has been shown to skew CD4+ T cells toward a TH-17 phenotype in tissues. We identified that histone demethylase JARID1C was significantly decreased in diabetic pDCs compared to controls. JARID1C is an epigenetic enzyme responsible for demethylating lysine 4 on histone 3, resulting in gene transcription inhibition. We demonstrate that type 1 interferons regulate JARID1C expression via TYK2/JAK1,3 mechanism. Finally, we show that in vitro administration of recombinant JARID1C decreases IL-6 production and TH17 T-cell expression. Taken together, these data suggest that, in diabetes, pDCs are epigenetically altered to increase IL-6 expression and direct the adaptive immune response toward pathologic TH17 CD4+ T-cell-mediated chronic inflammation and poor wound healing.