Nrf2 silencing amplifies DNA photooxidative damage to activate the STING pathway for synergistic tumor immunotherapy.

Photodynamic therapy (PDT)-mediated antitumor immune response depends on oxidative stress intensity and subsequent immunogenic cell death (ICD) in tumor cells, yet the inherent antioxidant system restricts reactive oxygen species (ROS)-associated oxidative damage, which is highly correlated with the upregulated nuclear factor erythroid 2-related factor 2 (Nrf2) and the downstream products, such as glutathione (GSH). Herein, to overcome this dilemma, we designed a versatile nanoadjuvant (RI@Z-P) to enhance the sensitivity of tumor cells to oxidative stress via Nrf2-specific small interfering RNA (siNrf2). The constructed RI@Z-P could significantly amplify photooxidative stress and achieve robust DNA oxidative damage, activating the stimulator of interferon genes (STING)-dependent immune-sensing to produce interferon-ß (IFN-ß). Additionally, RI@Z-P together with laser irradiation reinforced tumor immunogenicity by exposing or releasing damage-associated molecular patterns (DAMPs), showing the prominent adjuvant effect for promoting dendritic cell (DC) maturation and T-lymphocyte activation and even alleviating the immunosuppressive microenvironment to some extent.

Cellular Heterogeneity and Plasticity of Skin Epithelial Cells in Wound Healing and Tumorigenesis.

Cellular differentiation, the fundamental hallmark of cells, plays a critical role in homeostasis. And stem cells not only regulate the process where embryonic stem cells develop into a complete organism, but also replace ageing or damaged cells by proliferation, differentiation and migration. In characterizing distinct subpopulations of skin epithelial cells, stem cells show large heterogeneity and plasticity for homeostasis, wound healing and tumorigenesis. Epithelial stem cells and committed progenitors replenish each other or by themselves owing to the remarkable plasticity and heterogeneity of epidermal cells under certain circumstance. The development of new assay methods, including single-cell RNA sequence, lineage tracing assay, intravital microscopy systems and photon-ablation assay, highlight the plasticity of epidermal stem cells in response to injure and tumorigenesis. However, the critical mechanisms and key factors that regulate cellular plasticity still need for further exploration. In this review, we discuss the recent insights about the heterogeneity and plasticity of epithelial stem cells in homeostasis, wound healing and skin tumorigenesis. Understanding how stem cells collaborate together to repair injury and initiate tumor will offer new solutions for relevant diseases. Schematic abstract of cellular heterogeneity and plasticity of skin epithelial cells in wound healing and tumorigenesis.

Dietary supplementation with N-3 polyunsaturated fatty acid-enriched fish oil promotes wound healing after ultraviolet B-induced sunburn in mice.

N-3 polyunsaturated fatty acids (n-3 PUFA) can alleviate ultraviolet B (UVB)-induced skin cancers, but their effects on sunburn and upcoming wound healing remain controversial. This study aimed to explore the impact of n-3 PUFA-enriched fish oil (n-3 PUFA-FO) on UVB-induced sunburns and subsequent healing. Sixty C57BL/6 female mice were divided into two groups. The treated group mice were fed n-3 PUFA-FO for the entire duration of the experiment. Mice in the control group were fed a standard diet. After two weeks of n-3 PUFA-FO feeding, mice were exposed to UVB for 20 min and sacrificed 20 d later. Skin photodamage and lesion area were recorded during wound healing. Epidermal lesion thickness was quantified in hematoxylin and eosin-stained skin sections. Inflammation and macrophage polarization were assessed by qRT-PCR. Oxidative stress and antioxidant enzyme activity were quantified using specific ELISA kits. N-3 PUFA-FO feeding decreased UVB photodamage and accelerated wound healing progression, both of which were coupled with less intense inflammation and increased macrophage M2 phenotype polarization. Furthermore, n-3 PUFA-FO brought about a decrease in malondialdehyde (MDA) levels but increased the activity of catalase (CAT) and glutathione peroxidase (GP), without changing superoxide dismutase (SOD) activity. N-3 PUFA-FO protects against UVB-induced skin photodamage and promotes wound healing by modulating macrophage phenotypic polarization and antioxidant enzyme activities. N-3 PUFA-FO could be a novel therapeutic approach for both the prevention and treatment of sunburns.

Porcine Acellular Dermal Matrix Increases Fat Survival Rate after Fat Grafting in Nude Mice.

BACKGROUND: Autologous fat grafts have been widely in use for reconstruction, contour abnormalities, and cosmetic surgeries. However, the grafted fat one-year survival rate is unpredictable and always low (20%-80%). Standardizing the existing transplantation technology is difficult due to the limiting conditions. Scaffold materials or drugs are unsuitable to employ because of legal restrictions, complex production, and undetermined hazards. Therefore, a simpler and more effective approach to improve grafted fat survival rate is using commercial products as additives. Earlier studies proved that porcine acellular dermal matrix (PADM), a biomaterial clinically used for wound repair, could work as a scaffold for lipo-implantation. This study aimed at investigating the hitherto unclear effect of PADM on transplanted fat survival. METHODS: Thirty-two 8-week-old female nude mice were divided into two groups. Control mice received a 300 µl fat injection, while the PADM group mice were injected with a 300 µl PADM-fat mixture. After a 4-week treatment, fat weight and liquefaction ratio were assessed. Histological changes were quantified via hematoxylin & eosin (H&E) staining. Macrophage infiltration and vascular regeneration were revealed using an anti-CD34 antibody. Mouse and human mRNA expression levels were gauged via RNA-sequencing. On the third day post implantation, the mRNA expression levels of inflammatory genes Mcp-1 and Tnf-α were measured by qRT-PCR. RESULTS: The weight of surviving grafted fat did not differ between the control and the PADM group. However, adding PADM significantly decreased fat liquefaction. H&E-stained sections showed that PADM decreased fat necrosis, increased fat tissue regeneration, and raised CD34 levels in the regenerated tissue. RNA-sequencing showed that, compared to controls, fats from PADM-added group expressed more mouse-related mRNA but less human-related mRNA. The following GO and KEGG analysis showed that added PADM increased extracellular matrix (ECM) genes expression levels. The qRT-PCR showed that adding PADM increased Mcp-1 and Tnf-α mRNA expression levels. CONCLUSIONS: In summary, PADM addition increased fat survival rate by reducing fat liquefaction through an increased macrophage infiltration, ECM regeneration, and revascularization. Therefore, PADM addition is a workable application in autologous fat grafting. NO LEVEL ASSIGNED: 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 Foot Skin Microbiome of Patients with Diabetes Mellitus Using High-Throughput 16S rRNA Gene Sequencing: A Case Control Study from a Single Center.

BACKGROUND Worldwide, the treatment of complications associated with type 2 diabetes mellitus, including diabetic foot ulcer (DFU), results in an economic burden for patients and healthcare systems. This study aimed to use high-throughput 16S rRNA gene sequencing to investigate the changes in foot skin microbiome of patients with diabetes mellitus from a single center in China. MATERIAL AND METHODS Fifty-two participants were divided into 4 study groups: healthy controls (n=13); patients with short-term diabetes (<2 years; n=13); patients with intermediate-term diabetes (5-8 years; n=13); and patients with long-term diabetes (>10 years; n=13). Swabs were analyzed from the intact skin of the foot arch using high-throughput 16S ribosomal RNA sequencing. RESULTS Microbiome phylogenic diversity varied significantly between the study groups (whole tree, P<0.01; Chao1, P<0.01), but were similar within the same group. The findings were supported by non-parametric multidimensional scaling (stress=0.12) and principal component analysis (principal component 1, 8.38%; principal component 2, 5.28%). In patients with diabetes mellitus, the dominant skin microbial phyla were Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes. CONCLUSIONS High-throughput 16S rRNA gene sequencing showed dynamic changes in the skin microbiome from the foot during the progression of diabetes mellitus. These findings support the importance of understanding the role of the skin microbiota in the pathogenesis of DFU.

Platelet sonicates activate hair follicle stem cells and mediate enhanced hair follicle regeneration.

An increasing number of studies show that platelet-rich plasma (PRP) is effective for androgenic alopecia (AGA). However, the underlying cellular and molecular mechanisms along with its effect on hair follicle stem cells are poorly understood. In this study, we designed to induce platelets in PRP to release factors by calcium chloride (PC) or by sonication where platelet lysates (PS) or the supernatants of platelet lysate (PSS) were used to evaluate their effect on the hair follicle activation and regeneration. We found that PSS and PS exhibited a superior effect in activating telogen hair follicles than PC. In addition, PSS injection into the skin activated quiescent hair follicles and induced K15+ hair follicle stem cell proliferation in K14-H2B-GFP mice. Moreover, PSS promoted skin-derived precursor (SKP) survival in vitro and enhanced hair follicle formation in vivo. In consistence, protein array analysis of different PRP preparations revealed that PSS contained higher levels of 16 growth factors (out of 41 factors analysed) than PC, many of them have been known to promote hair follicle regeneration. Thus, our data indicate that sonicated PRP promotes hair follicle stem cell activation and de novo hair follicle regeneration.

Enhanced cutaneous wound healing by functional injectable thermo-sensitive chitosan-based hydrogel encapsulated human umbilical cord-mesenchymal stem cells.

Human umbilical cord-mesenchymal stem cells (hUCMSCs) can secrete a variety of cytokines and growth factors promoting wound repair. Hydrogel is suitable biomaterial to supply niche for cells adhesion and survival. This study constructed a functional injectable thermo-sensitive hydrogel (chitosan/glycerol phosphate sodium/cellulose nanocrystals, CS/GP/CNC) encapsulated hUCMSCs to repair full-thickness cutaneous wound. Addition of CNC to the CS/GP system not only accelerated the gel speed, but also greatly improved the mechanical properties of the gel and decreased degradation rate. The novel hydrogel was injectable and low toxicity. Histological detection showed that hydrogel-hUCMSCs combination significantly accelerated wound closure, microcirculation, tissue remodeling, re-epithelialization and hair follicle regeneration, and inhibited over-inflammation in the central and surrounding wounds. The hydrogel-hUCMSCs combination promoted collagen deposition and keratinocyte mature marker K1 expression, decreased inflammatory factors secretion namely TNF-α and IL-1ß. The present data provides a potential strategy for treatment of non-healing chronic cutaneous wounds.

TSA restores hair follicle-inductive capacity of skin-derived precursors.

The genesis of the hair follicle relies on signals derived from mesenchymal cells in the dermis during skin morphogenesis and regeneration. Multipotent skin-derived precursors (SKPs), which exhibit long term proliferation potential when being cultured in spheroids, have been shown to induce hair genesis and hair follicle regeneration in mice, implying a therapeutic potential of SKPs in hair follicle regeneration and bioengineering. However, the hair-inductive property of SKPs declines progressively upon ex vivo culture expansion, suggesting that the expressions of the genes responsible for hair induction are epigenetically unstable. In this study, we found that TSA markedly alleviated culture expansion induced SKP senescence, increased the expression and activity of alkaline phosphatase (AP) in the cells and importantly restored the hair inductive capacity of SKPs. TSA increased the acetylation level of histone H3, including the K19/14 sites in the promoter regions of bone morphogenetic proteins (BMPs) genes, which were associated with elevated gene expression and BMP signaling activity, suggesting a potential attribution of BMP pathway in TSA induced recovery of the hair inductive capacity of SKPs.

Microbiome Imbalances: An Overlooked Potential Mechanism in Chronic Nonhealing Wounds.

Chronic nonhealing wounds are a severe burden to health care systems worldwide, causing millions of patients to have lengthy hospital stays, high health care costs, periods of unemployment, and reduced quality of life. Moreover, treating chronic nonhealing wounds effectively and reasonably in countries with limited medical resources can be extremely challenging. With many outstanding questions surrounding chronic nonhealing wounds, in this review, we offer changes to the microbiome as a potentially ignored mechanism important in the formation and treatment of chronic wounds. Our analysis helps bring a whole new understanding to wound formation and healing and provides a potential breakthrough in the treatment of chronic nonhealing wounds in the future.

A series of models of non-thermal high voltage electrical injuries.

Although many models of electrical injury have been established, none of them are completely typical of the clinical features of electrical injury. As a result, research based on these models were incapable of explaining many clinical phenomena such as continuous tissue necrosis and also were unable to cope with high ratio of amputation of extremities. In order to investigate the mechanism of electrical injuries and better model the condition with similar clinical characteristics we developed a new model. Seventy-five New Zealand rabbits were employed in this study, of them 45 were used in a preliminary experiment including the selection of the size of electrode plate area, damaged extent, time length of electrical injury and interval length between two injuries and so on. Another 30 rabbits were equally divided into five groups with electrical injury times of 6, 12, 18, 24 and 30 cycles, respectively. Observations were made using clinical anatomical exploration, with quantification using an IDBI scale on the 2nd, 8th, 24th, 48th hours and 5th, 15th days, and TC-99m-DMP isotope scanning and gamma photography at 2nd hour and 5th day in post-injury, respectively. The results showed the effective electric field strength was 17,000 V/m, mean current intensity was 554 mA, average current density was 137 mA/cm(2) beneath the small electrode plate with 21 mA/cm(2) beneath big one, and average increase of tissue temperature was 1.73 degrees C during injury process which excluded the possibility of thermal injury. One single wound injury beneath the small plate of the experimental rabbits with loss of injured extremities from 5th to 15th post-injury days in groups 3-5 and obviously progressive tissue necrosis in and outside the wounds were obtained. A series of electrical injured models from mild, moderate, severe, extra severe, and destructive which was exactly similar to the clinical features of electrical injury cases was established.

[Preventing scarring in split-thickness skin donor sites with epidermal grafting].

OBJECTIVE: Introducing a new technique for preventing the scar growthing in split thickness skin donor sites using the great sheets of epidermis covering. METHODS: The donor sites of split thickness skin were grafting with the great sheets of the epidermis, of the thickness about 0.07 approximately 0.12 mm, harvested by electrical power dermatome and fixed the edges of the epidermal sheet with the verges of donor wound together using the nanoparticles-Ag-gauze stripes adding the sutures or skin stapler, dressing the wounds with the nanoparticles-Ag-gauze using the tie-over technique, left the dressing entire for a 5-day period. RESULTS: This method were used in a total of 209 donor sites of both the split-thickness skin and epidermis for 133 reconstructed sites of 118 cases from November 1999 to November 2003, and the smooth, near normal skin appearance without scarring were obtained in the split thickness skin donor sites, and the epidermal donor sites healed good enough 5 days after surgery, and skin appearance is near normal in 3 months later. CONCLUSIONS: Covering the donor sites of split thickness skin with the large sheets of epidermis is an effective and useful method for preventing the scarring in the split thickness skin donor sites.