A Frog Skin-Derived Peptide Targeting SCD1 Exerts Radioprotective Effects Against Skin Injury by Inhibiting STING-Mediated Inflammation.

The extensive application of nuclear technology has increased the potential of uncontrolled radiation exposure to the public. Since skin is the largest organ, radiation-induced skin injury remains a serious medical concern. Organisms evolutionally develop distinct strategies to protect against environment insults and the related research may bring novel insights into therapeutics development. Here, 26 increased peptides are identified in skin tissues of frogs (Pelophylax nigromaculatus) exposed to electron beams, among which four promoted the wound healing of irradiated skin in rats. Specifically, radiation-induced frog skin peptide-2 (RIFSP-2), from histone proteolysis exerted membrane permeability property, maintained cellular homeostasis, and reduced pyroptosis of irradiated cells with decreased TBK1 phosphorylation. Subsequently, stearyl-CoA desaturase 1 (SCD1) is identified, a critical enzyme in biogenesis of monounsaturated fatty acids (MUFAs) as a direct target of RIFSP-2 based on streptavidin-biotin system. The lipidomic analysis further assured the restrain of MUFAs biogenesis by RIFSP-2 following radiation. Moreover, the decreased MUFA limited radiation-induced and STING-mediated inflammation response. In addition, genetic depletion or pharmacological inhibition of STING counteracted the decreased pyroptosis by RIFSP-2 and retarded tissue repair process. Altogether, RIFSP-2 restrains radiation-induced activation of SCD1-MUFA-STING axis. Thus, the stress-induced amphibian peptides can be a bountiful source of novel radiation mitigators.

Current insights and future perspectives of ultraviolet radiation (UV) exposure: Friends and foes to the skin and beyond the skin.

Ultraviolet (UV) radiation is ubiquitous in the environment, which has been classified as an established human carcinogen. As the largest and outermost organ of the body, direct exposure of skin to sunlight or UV radiation can result in sunburn, inflammation, photo-immunosuppression, photoaging and even skin cancers. To date, there are tactics to protect the skin by preventing UV radiation and reducing the amount of UV radiation to the skin. Nevertheless, deciphering the essential regulatory mechanisms may pave the way for therapeutic interventions against UV-induced skin disorders. Additionally, UV light is considered beneficial for specific skin-related conditions in medical UV therapy. Recent evidence indicates that the biological effects of UV exposure extend beyond the skin and include the treatment of inflammatory diseases, solid tumors and certain abnormal behaviors. This review mainly focuses on the effects of UV on the skin. Moreover, novel findings of the biological effects of UV in other organs and systems are also summarized. Nevertheless, the mechanisms through which UV affects the human organism remain to be fully elucidated to achieve a more comprehensive understanding of its biological effects.

SOD2 promotes the immunosuppressive function of mesenchymal stem cells at the expense of adipocyte differentiation.

The potent immunomodulatory function of mesenchymal stem/stromal cells (MSCs) elicited by proinflammatory cytokines IFN-γ and TNF-α (IT) is critical to resolve inflammation and promote tissue repair. However, little is known about how the immunomodulatory capability of MSCs is related to their differentiation competency in the inflammatory microenvironment. In this study, we demonstrate that the adipocyte differentiation and immunomodulatory function of human adipose tissue-derived MSCs (MSC(AD)s) are mutually exclusive. Mitochondrial reactive oxygen species (mtROS), which promote adipocyte differentiation, were decreased in MSC(AD)s due to IT-induced upregulation of superoxide dismutase 2 (SOD2). Furthermore, knockdown of SOD2 led to enhanced adipogenic differentiation but reduced immunosuppression capability of MSC(AD)s. Interestingly, the adipogenic differentiation was associated with increased mitochondrial biogenesis and upregulation of peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PPARGC1A/PGC-1α) expression. IT inhibited PGC-1α expression and decreased mitochondrial mass but promoted glycolysis in an SOD2-dependent manner. MSC(AD)s lacking SOD2 were compromised in their therapeutic efficacy in DSS-induced colitis in mice. Taken together, these findings indicate that the adipogenic differentiation and immunomodulation of MSC(AD)s may compete for resources in fulfilling the respective biosynthetic needs. Blocking of adipogenic differentiation by mitochondrial antioxidant may represent a novel strategy to enhance the immunosuppressive activity of MSCs in the inflammatory microenvironment.

Altered bile acid metabolism in skin tissues in response to ionizing radiation: deoxycholic acid (DCA) as a novel treatment for radiogenic skin injury.

OBJECTIVE: Radiogenic skin injury (RSI) is a common complication during cancer radiotherapy or accidental exposure to radiation. The aim of this study is to investigate the metabolism of bile acids (BAs) and their derivatives during RSI. METHODS: Rat skin tissues were irradiated by an X-ray linear accelerator. The quantification of BAs and their derivatives were performed by liquid chromatography-mass spectrometry (LC-MS)-based quantitative analysis. Key enzymes in BA biosynthesis were analyzed from single-cell RNA sequencing (scRNA-Seq) data of RSI in the human patient and animal models. The in vivo radioprotective effect of deoxycholic acid (DCA) was detected in irradiated SD rats. RESULTS: Twelve BA metabolites showed significant differences during the progression of RSI. Among them, the levels of cholic acid (CA), DCA, muricholic acid (MCA), chenodeoxycholic acid (CDCA), glycocholic acid (GCA), glycohyodeoxycholic acid (GHCA), 12-ketolithocholic acid (12-ketoLCA) and ursodeoxycholic acid (UDCA) were significantly elevated in irradiated skin, whereas lithocholic acid (LCA), tauro-ß-muricholic acid (Tß-MCA) and taurocholic acid (TCA) were significantly decreased. Additionally, the results of scRNA-Seq indicated that genes involved in 7a-hydroxylation process, the first step in BA synthesis, showed pronounced alterations in skin fibroblasts or keratinocytes. The alternative pathway of BA synthesis is more actively altered than the classical pathway after ionizing radiation. In the model of rat radiogenic skin damage, DCA promoted wound healing and attenuated epidermal hyperplasia. CONCLUSIONS: Ionizing radiation modulates the metabolism of BAs. DCA is a prospective therapeutic agent for the treatment of RSI.

Ubiquitin-specific peptidase 47 (USP47) regulates cutaneous oxidative injury through nicotinamide nucleotide transhydrogenase (NNT).

Human skin is daily exposed to oxidative stresses in the environment such as physical stimulation, chemical pollutants and pathogenic microorganisms, which are likely to cause skin diseases. As important post-translational modifications, protein ubiquitination and deubiquitination play crucial roles in maintaining cellular homeostasis by the proteolytic removal of oxidized proteins. We have previously reported that the expression of ubiquitin-specific protease 47 (USP47), a kind of deubiquitinating enzymes (DUBs), was significantly elevated in response to oxidative stress. However, the role of USP47 in cutaneous oxidative injury remains unclear. Usp47 wild-type (Usp47+/+) mice and Usp47 knockout (Usp47-/-) mice were used to establish two animal models of oxidative skin damage: (1) radiation- and (2) imiquimod (IMQ)-induced skin injury. Loss of Usp47 consistently aggravated mouse skin damage in vivo. Subsequently, we screened 63 upregulated and 170 downregulated proteins between the skin tissues of wild-type and Usp47-/- mice after 35 Gy electron beam radiation using proteomic analysis. Among the dysregulated proteins, nicotinamide nucleotide transhydrogenase (NNT), which has been reported as a significant regulator of oxidative stress and redox homeostasis, was further investigated in detail. Results showed that NNT was regulated by USP47 through direct ubiquitination mediated degradation and involved in the pathogenesis of cutaneous oxidative injury. Knockdown of NNT expression dramatically limited the energy production ability, with elevated mitochondrial reactive oxygen species (ROS) accumulation and increased mitochondrial membrane potential in irradiated HaCaT cells. Taken together, our present findings illustrate the critical role of USP47 in oxidative skin damage by modulating NNT degradation and mitochondrial homeostasis.

Screening and identification of the core immune-related genes and immune cell infiltration in severe burns and sepsis.

Severe burns often have a high mortality rate due to sepsis, but the genetic and immune crosstalk between them remains unclear. In the present study, the GSE77791 and GSE95233 datasets were analysed to identify immune-related differentially expressed genes (DEGs) involved in disease progression in both burns and sepsis. Subsequently, weighted gene coexpression network analysis (WGCNA), gene enrichment analysis, protein-protein interaction (PPI) network construction, immune cell infiltration analysis, core gene identification, coexpression network analysis and clinical correlation analysis were performed. A total of 282 common DEGs associated with burns and sepsis were identified. Kyoto Encyclopedia of Genes and Genomes pathway analysis identified the following enriched pathways in burns and sepsis: metabolic pathways; complement and coagulation cascades; legionellosis; starch and sucrose metabolism; and ferroptosis. Finally, six core DEGs were identified, namely, IL10, RETN, THBS1, FGF13, LCN2 and MMP9. Correlation analysis showed that some core DEGs were significantly associated with simultaneous dysregulation of immune cells. Of these, RETN upregulation was associated with a worse prognosis. The immune-related genes and dysregulated immune cells in severe burns and sepsis provide potential research directions for diagnosis and treatment.

Revealing the alloying and dealloying behaviours in AuAg nanorods by thermal stimulus.

Binary metallic nanocrystals are attractive as they offer an extra degree of freedom for structure and phase modulation to generate synergistic effects and extraordinary properties. However, whether the binary structures and phases at the nanoscale still follow the rules established on the bulk counterparts remains unclear. In this work, AuAg nanorods were used as a sample to probe into this issue. An in situ heating method by combining aberration-corrected transmission electron microscopes with a chip-based heating holder was employed to perform the heating experiments. It was found that the AuAg nanorods, which initially possessed heterostructures, can be designed and engineered to be gradient phase alloys with thermal pulses over 350 °C. Atomic diffusion inside the rod structures did not alter the shape of the rods but provided a route to fine-tune their properties. At higher temperatures, the discrepant sublimation behaviours between Au and Ag lead to dealloying of the nanorods. Durative sublimation of the Ag element can continuously tailor the lengths of the nanorods while concentrating the Au composition simultaneously. Especially, nearly pure Au nanocrystals can be obtained with the depletion of Ag by sublimation. These findings give insights into the nanoscale structure and phase behaviours in binary alloys and provide an alternative way to fine-tune their structure, phase, and properties.

Molecular response of keloids to ionizing radiation: targeting FOXO1 radiosensitizes keloids.

PURPOSE: Keloids are benign dermal tumors that arise from abnormal wound healing processes following skin lesions. Surgical excision followed by radiotherapy plays an important role in the treatment of keloids. Nevertheless, radioresistance remains a serious impediment to treatment efficacy. Investigation of the molecular response of keloids to radiation may contribute to radiosensitizing strategies. MATERIALS AND METHODS: Primary keloid fibroblasts from human keloids were isolated and irradiated with X-ray. The expression profiles of messenger RNA (mRNA) in nonradiated and irradiated primary keloid fibroblasts were measured by mRNA sequencing analysis. Then, we identified common motifs and corresponding transcription factors of dysregulated mRNAs by using bioinformatic analysis of the proximal promoters. Whereafter, GO and KEGG were used to analyze the functional enrichment of the differentially expressed genes. RESULTS: We found that radiation not only suppressed proliferation but also increased cell senescence of primary keloid fibroblasts. There were 184 mRNAs and 204 mRNAs that showed significant changes in 4 and 8 Gy irradiated primary keloid fibroblasts, respectively. Among them, 8 upregulated and 30 downregulated mRNAs showed consistent alterations in 4 and 8 Gy irradiated primary keloid fibroblasts. More importantly, the xForkhead box O1 (FOXO1) signaling pathway was involved in the irradiation response. Pretreatment with the FOXO1 signaling inhibitor AS1842856 significantly promoted LDH release, apoptosis and senescence of primary keloid fibroblasts following irradiation. CONCLUSION: Our findings illustrated the molecular changes in human keloid fibroblasts in response to radiation, and FOXO1 pathway inhibition is expected to provide a novel strategy for the radiosensitization of keloids.

Therapeutic targets and signaling mechanisms of dasatinib activity against radiation skin ulcer.

Objective: To reveal the potential targets and signaling pathways of dasatinib in the treatment of radiation ulcers through network pharmacology and molecular docking technology. Methods: Pathological targets of radiation ulcers were screened using GeneCards database. At the same time, the pharmacological targets of dasatinib were obtained through SwissTargetPrediction (STP), Binding DB and Drugbank databases. Subsequently, the potential targets of dasatinib for anti-radiation ulcers were obtained after intersection by Venn diagram. Next, a protein-protein interaction (PPI) network was constructed through the STRING database and core targets were screened. Finally, the identified core targets were subjected to GO and KEGG enrichment analysis, co-expression network analysis, and molecular docking technology to verify the reliability of the core targets. Results: A total of 76 potential targets for anti-radiation ulcer with dasatinib were obtained, and 6 core targets were screened, including EGFR, ERBB2, FYN, JAK2, KIT, and SRC. These genes were mainly enriched in Adherens junction, EGFR tyrosine kinase inhibitor resistance, Focal adhesion, Bladder cancer and PI3K-Akt signaling pathway. Molecular docking results showed that dasatinib binds well to the core target. Conclusion: Dasatinib may play a role in the treatment of radiation ulcers by regulating EGFR, ERBB2, FYN, JAK2, KIT, and SRC. These core targets may provide new insights for follow-up studies of radiation ulcers.

Data-driven analysis to identify prognostic immune-related biomarkers in BRAF mutated cutaneous melanoma microenvironment.

Skin cutaneous melanoma is one of the deadly diseases, and more than 50% of the patients have BRAF gene mutations. Evidence suggests that oncogenic BRAF modulates the immune system's ability to recognize SKCM cells. Due to the complexity of the tumor microenvironment (TME) and a lack of a rational mechanistic basis, it is urgent to investigate the immune infiltration and identify prognostic biomarkers in BRAF mutated SKCM patients. Multiple methods including ESTIMATE algorithm, differential gene analysis, prognostic analysis and immune infiltration analysis were performed to investigate the tumor microenvironment. Based on the patient's immune score and stromal score, immune-related genes DEGs were identified. Functional analysis revealed that these genes were mainly enriched in biological processes such as immune response, defense response and positive regulation of immune system. Furthermore, we analyzed the immune infiltrating cell components of BRAF mutated patients and revealed 4 hub genes associated with overall survival time. Several cells (Monocyte, Macrophage and Gamma delta cells) have been found to be significantly decreased in immune-high BRAF mutated SKCM group. While CD4+T, CD8+T, CD4 naïve, Tr1, Th2 and many T cell subsets were significantly increased in immune-high group. These immune cells and genes were closely related to each other. This study revealed that the dysregulation of immune function and immune cells may contribute to the poor outcomes of BRAF mutated patients. It is of great significance to our further understanding of the TME and immune dysfunction in BRAF mutated SKCM.

Exploring the alterations and function of skin microbiome mediated by ionizing radiation injury.

Background: Radiation-induced skin injury (RISI) is still the most common and severe side effect of radiotherapy. The role of the skin's microbial barrier in the pathogenesis and progression of RISI needs to be fully investigated. Methods: This study aimed to explore the alterations in and functions of the skin microbiota in RISI. We applied the unculturable approach to characterize the cutaneous microbiomes of a radiation-induced animal model by sequencing the V1-V3 regions of the 16S ribosomal RNA (rRNA) gene. Combined with the downloaded clinical data of patients, a comprehensive analysis was performed to identify potential radioprotective species and metabolic pathways. Results: There were no significant differences in the alpha diversity indices (Sobs, Shannon, Simpson, Ace, and Chao) between the acute radiation injury and control groups. Phylum-level analysis of the RISI microbiomes exhibited significant predominance of Firmicutes (mean abundance = 67%, corrected p = 0.0035). The high abundance of Firmicutes was significantly associated with rapid healing of RISI (average relative abundance = 52%; Kruskal-Wallis: p = 5.7E-4). Among its members, Streptococcus, Staphylococcus, Acetivibrio ethanolgignens group, Peptostreptococcus, Anaerofilum, and UCG-002 [linear discriminant analysis (LDA) > 3, p < 0.05] were identified as the core genera of Firmicutes. In addition, Lachnosiraceae and Lactobacillus occupied an important position in the interaction network (r > 0.6, p < 0.05). The differential metabolic pathways of RISI were mainly associated with carbohydrate metabolism (butanoate and propanoate metabolism), amino acid metabolism (tryptophan and histidine metabolism), energy metabolism, and lipid metabolism (fatty acid degradation and biosynthesis). Conclusion: This study provides new insights into the potential mechanism and skin microbial changes in the progression of RISI. The overwhelming predominance of members of Firmicutes, including Streptococcaceae, Staphylococcaceae, Lachnospiraceae, and Lactobacillus, is potentially related to rapid healing of RISI. The microbiota-metabolite axis plays a critical role in RISI and provides promising therapeutic targets for the treatment of adverse side effects.

Mechanisms underlying the therapeutic effects of 4-octyl itaconate in treating sepsis based on network pharmacology and molecular docking.

Objective: Through network pharmacology and molecular docking technology, the hub genes, biological functions, and signaling pathways of 4-Octyl itaconate (4-OI) against sepsis were revealed. Methods: Pathological targets of sepsis were screened using GeneCards and GEO databases. Similarly, the pharmacological targets of 4-OI were obtained through Swiss TargetPrediction (STP), Similarity ensemble approach (SEA), and TargetNet databases. Then, all the potential targets of 4-OI anti-sepsis were screened by the online platform Draw Venn diagram, and the hub genes were screened by Cytoscape software. The identified hub genes were analyzed by GO and KEGG enrichment analysis, protein interaction (PPI) network, and molecular and docking technology to verify the reliability of hub gene prediction, further confirming the target and mechanism of 4-OI in the treatment of sepsis. Results: After the target screening of 4-OI and sepsis, 264 pharmacological targets, 1953 pathological targets, and 72 genes related to 4-OI anti-sepsis were obtained, and eight hub genes were screened, namely MMP9, MMP2, SIRT1, PPARA, PTPRC, NOS3, TLR2, and HSP90AA1. The enrichment analysis results indicated that 4-OI might be involved in regulating inflammatory imbalance, immunosuppression, and oxidative stress in developing sepsis. 4-OI protects multiple organ dysfunction in sepsis by acting on hub genes, and MMP9 is a reliable gene for the prognosis and diagnosis of sepsis. The molecular docking results showed that 4-OI binds well to the hub target of sepsis. Conclusion: 4-OI plays an antiseptic role by regulating MMP9, MMP2, SIRT1, PPARA, PTPRC, NOS3, TLR2 and HSP90AA1. These Hub genes may provide new insights into follow-up research on the target of sepsis treatment.

Transcriptional data analysis reveals the association between infantile hemangiomas and venous malformations.

Background: Infantile hemangiomas (IH) and venous malformations (VM) are the most common types of vascular abnormalities that seriously affect the health of children. Although there is evidence that these two diseases share some common genetic changes, the underlying mechanisms need to be further studied. Methods: The microarray datasets of IH (GSE127487) and VM (GSE7190) were downloaded from GEO database. Extensive bioinformatics methods were used to investigate the common differentially expressed genes (DEGs) of IH and VM, and to estimate their Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Trough the constructing of protein-protein interaction (PPI) network, gene models and hub genes were obtained by using Cytoscape and STRING. Finally, we analyzed the co-expression and the TF-mRNA-microRNA regulatory network of hub genes. Results: A total of 144 common DEGs were identified between IH and VM. Functional analysis indicated their important role in cell growth, regulation of vasculature development and regulation of angiogenesis. Five hub genes (CTNNB1, IL6, CD34, IGF2, MAPK11) and two microRNA (has-miR-141-3p, has-miR-150-5p) were significantly differentially expressed between IH and normal control (p < 0.05). Conclusion: In conclusion, our study investigated the common DEGs and molecular mechanism in IH and VM. Identified hub genes and signaling pathways can regulate both diseases simultaneously. This study provides insight into the crosstalk of IH and VM and obtains several biomarkers relevant to the diagnosis and pathophysiology of vascular abnormalities.

Genetic and immune crosstalk between severe burns and blunt trauma: A study of transcriptomic data.

Background: Severe burns and blunt trauma can lead to multiple organ dysfunction syndrome, the leading cause of death in intensive care units. In addition to infection, the degree of immune inflammatory response also affects prognosis. However, the characteristics and clinical relevance of the common mechanisms of these major diseases are still underexplored. Methods: In the present study, we performed microarray data analysis to identify immune-related differentially expressed genes (DEGs) involved in both disease progression in burns and blunt trauma. Six analyses were subsequently performed, including gene enrichment analysis, protein-protein interaction (PPI) network construction, immune cell infiltration analysis, core gene identification, co-expression network analysis, and clinical correlation analysis. Results: A total of 117 common immune-related DEGs was selected for subsequent analyses. Functional analysis emphasizes the important role of Th17 cell differentiation, Th1 and Th2 cell differentiation, Cytokine-cytokine receptor interaction and T cell receptor signaling pathway in these two diseases. Finally, eight core DEGs were identified using cytoHubba, including CD8A, IL10, CCL5, CD28, LCK, CCL4, IL2RB, and STAT1. The correlation analysis showed that the identified core DEGs were more or less significantly associated with simultaneous dysregulation of immune cells in blunt trauma and sepsis patients. Of these, the downregulation of CD8A and CD28 had a worse prognosis. Conclusion: Our analysis lays the groundwork for future studies to elucidate molecular mechanisms shared in burns and blunt trauma. The functional roles of identified core immune-related DEGs and dysregulated immune cell subsets warrant further in-depth study.

Exploring Potential Biomarkers, Ferroptosis Mechanisms, and Therapeutic Targets Associated with Cutaneous Squamous Cell Carcinoma via Integrated Transcriptomic Analysis.

Background: Cutaneous squamous cell carcinoma (cSCC) is the leading cause of death in patients with nonmelanoma skin cancers (NMSC). However, the unclear pathogenesis of cSCC limits the application of molecular targeted therapy. Methods: Three microarray datasets (GSE2503, GSE45164, and GSE66359) were downloaded from the Gene Expression Omnibus (GEO). After identifying the differentially expressed genes (DEGs) in tumor and nontumor tissues, five kinds of analyses, namely, functional annotation, protein-protein interaction (PPI) network, hub gene selection, TF-miRNA-mRNA regulatory network analysis, and ferroptosis mechanism, were performed. Results: A total of 146 DEGs were identified with significant differences, including 113 upregulated genes and 33 downregulated genes. The enriched functions and pathways of the DEGs included microtubule-based movement, ATP binding, cell cycle, P53 signaling pathway, oocyte meiosis, and PLK1 signaling events. Nine hub genes were identified (CDK1, AURKA, RRM2, CENPE, CCNB1, KIAA0101, ZWINT, TOP2A, and ASPM). Finally, RRM2, AURKA, and SAT1 were identified as significant ferroptosis-related genes in cSCC. The differential expression of these genes has been verified in two other independent datasets. Conclusions: By integrated bioinformatic analysis, the hub genes identified in this study elucidated the molecular mechanism of the pathogenesis and progression of cSCC and are expected to become future biomarkers or therapeutic targets.

Data mining reveal the association between diabetic foot ulcer and peripheral artery disease.

Background: Diabetic foot ulcer (DFU) and peripheral artery disease (PAD) are common diseases that seriously affect the quality of life and bring a huge economic burden to society. Although mounting evidence supports a close link between the two disorders, the mechanisms of comorbidity remain to be fully elucidated. Methods: The gene expression profiles of DFU (GSE80178) and PAD (GSE100927) were downloaded from the Gene Expression Omnibus (GEO) database. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) performed pathway enrichment analysis for common differentially expressed genes (DEGs) present in DFU and PAD. Subsequently, we constructed a protein-protein interaction (PPI) network using the STRING database and detected core modules and hub genes in the network. Finally, we analyzed the co-expression network and the TF-miRNA-mRNA regulatory network of hub genes. Results: A total of 167 common DEGs (91 up-regulated genes and 76 down-regulated genes) was selected for subsequent analyses. Functional analysis emphasizes the important role of chemokines and cytokines in these two diseases. Finally, six hub genes were identified using cytoHubba, including CXCL8, IL1RN, MMP1, CD68, CCR7 and CCL3. Conclusions: The hub genes and signaling pathways involved can regulate both diseases simultaneously, suggesting a close relationship between the molecular mechanisms of the two diseases and possible targets for drugs that intervene in both diseases.

The role of human antigen R (HuR) in modulating proliferation, senescence and radiosensitivity of skin cells.

The skin is the largest outermost organ of the human body. It is vulnerable to various damages, such as ionizing radiation. Exploration of proliferation, senescence and radiosensitivity of skin cells contributes to the development of medical and cosmetic countermeasures against skin aging and toward injury protection. Human antigen R (HuR) is one of the most widely studied RNA-binding proteins and serves an important role in stabilization of mRNA and regulation of the expression of the target genes. To investigate the role of HuR in modulating proliferation, senescence and radiosensitivity of skin cells, the present study performed an in vitro study using lentivirus-mediated overexpression or silencing of HuR in human keratinocyte HaCaT cells and human skin fibroblast WS1 cells. The results indicated that overexpression of HuR promoted proliferation, whereas downregulation of HuR inhibited proliferation of HaCaT and WS1 cells. Overexpression of HuR reduced apoptosis and senescence in skin cells. RNA-Seq of skin cells with HuR overexpression or knockdown identified 77 mRNAs positively or negatively correlated with HuR expression levels. In addition, silencing of HuR induced a significant increase in radiogenic reactive oxygen species after irradiation. Overexpression of HuR increased radiotolerance of HaCaT and WS1 cells. RNA immunoprecipitation coupled with RNA-Seq identified 14 mRNAs interacting with HuR upon radiation exposure. Overall, the findings of the present study illustrated the key role of HuR in modulating proliferation, senescence and radiosensitivity of skin cells providing a new therapeutic strategy for cosmetic treatments and to combat skin injury.

Fenofibrate Attenuates Radiation-Induced Oxidative Damage to the Skin through Fatty Acid Binding Protein 4 (FABP4).

BACKGROUND: Radiation facilities and radioactive materials have been widely used in military, industry, medicine, science and nuclear facilities, which has significantly increased the potential of large-scale, uncontrolled exposure to radiation. The skin is one of the radiosensitive organ systems and radiation-induced skin injury remains a serious concern after ionizing radiation exposure. Our previous report indicates the involvement of the peroxisome proliferator-activated receptor pathway in the response of skin tissues to ionizing radiation. PPARα is a member of the PPAR nuclear hormone receptor superfamily, which can be activated by fibrate ligands. However, the protection of fenofibrate against ionizing radiation in skin keratinocytes and fibroblasts has not been described. METHODS: The PPARα mRNA levels in irradiated and nonirradiated skin tissues of rats were determined by real-time assay. The expression of PPARα, and FABP4 were evaluated by western blot and IHC assay. The cell proliferation was detected by colony formation. The γH2AX foci and ROS levels in irradiated WS1 cells with FABP4 overexpression than in control cells were performed by Immunofluorescence assay. RESULTS: We found that PPARα expression was lower in the irradiated skin tissues of mouse, rat, monkey, and human patients than in their nonirradiated counterparts. PPARα fenofibrate significantly decreased radiation-induced ROS and apoptosis in a dose-dependent manner in human keratinocyte HaCaT and skin fibroblast WS1 cells. Moreover, fenofibrate significantly decreased radiation-induced ROS and malondialdehyde (MDA) levels in electron beam irradiated skin tissues of rats. Mechanistically, the proximal promoter of fatty acid binding protein 4 (FABP4) harbored three binding sites of PPARα and fenofibrate stimulated the transcription of FABP4 in skin cells. FABP4 overexpression decreased radiation-induced ROS and γH2AX foci. FABP4 inhibitor BMS309403 abrogated the ROS-eliminating activity as well as the lipid-accumulating role of fenofibrate, indicating that FABP4 mediates the radioprotective role of fenofibrate. In addition, FABP4 overexpression significantly decreased radiation-induced oxidative damage in vivo. CONCLUSIONS: These results confirm that fenofibrate attenuated radiation-induced oxidative damage to the skin by stimulating FABP4.

Application of the Jigsaw Puzzle Flap Based on Freestyle Perforators to Repair Large and Deep Ulcers on the Buttocks.

Background: Decubitus ulcers are common skin injuries in plastic and burn surgery departments, usually occur in patients with a long disease course and poor underlying health. Designing a reconstruction procedure with safety blood supply to a large volume soft tissue and resulting in minimal trauma is a priority for surgeons. Methods: The free-style perforators on the potential donor sites surrounding the ulcers were detected by Doppler, and the area of the ulcer was divided into several sections based on the location of pre-design perforator flaps. According to the insertion point of the perforators, small V-Y advancement flaps, propeller flaps and rotation flaps pedicled with freestyle perforators were formed and moderately modified during surgery. All of the small flaps were transplanted from donor sites to the defect and reassembled into a new composite flap to repair the ulcer. The donor sites were directly closed. The area of the flaps ranged from 7.0 × 10.5 cm to 8.0 × 22.0 cm and the diameter of the pedicle perforators ranged from 0.5 to 4.0 mm. Results: In 30 patients, 65 flaps were constructed, and all of the flaps survived with direct closure of all donor sites. One case with effusion healed 1 month postoperatively through draining and application of a mild pressure dressing. After a 3-24 months follow-up period, all of the patients were satisfied with post-operative function and appearance, and only one case had a local recurrence 6 months postoperatively. Conclusion: The jigsaw puzzle flap based on freestyle perforators can repair the large skin and soft tissue defects caused by decubitus ulcers on the buttocks, with direct donor flap area closure. This method is easy to perform with a safe blood supply and minimal trauma resulting from the avoidance of microvascular anastomosis and the conventional myocutaneous flap.

Psoralen Suppresses Lipid Deposition by Alleviating Insulin Resistance and Promoting Autophagy in Oleate-Induced L02 Cells.

Non-alcoholic fatty liver disease (NAFLD) held a high global prevalence in recent decades. Hepatic lipid deposition is the major characteristic of NAFLD. We aim to explore the mechanisms of psoralen on lipid deposition in NAFLD. The effects of psoralen on insulin resistance, lipid deposition, the expression and membrane translocation of glucose transporter type 4 (GLUT4), autophagy, and lipogenesis enzymes were determined on sodium oleate-induced L02 cells. Chloroquine and 3-MA were employed. The AMP-activated protein kinase alpha (AMPKα) was knocked down by siRNA. Psoralen alleviated insulin resistance in sodium oleate-induced L02 hepatocytes by upregulating the expression and membrane translocation of GLUT4. Psoralen inhibited lipid accumulation by decreasing the expression of key lipogenesis enzymes. Psoralen promotes autophagy and the autophagic flux to enhance lipolysis. Psoralen promoted the fusion of the autophagosome with the lysosome. Both chloroquine and 3-MA blocked the effects of psoralen on autophagy and lipid accumulation. The AMPKα deficiency attenuated the effects of psoralen on autophagy and lipid accumulation. Our study demonstrated that as an antioxidant, psoralen attenuates NAFLD by alleviating insulin resistance and promoting autophagy via AMPK, suggesting psoralen to be a promising candidate for NAFLD.