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Background: One of the key obstacles to the healing of diabetic wound is the persistence of active inflammation. We previously demonstrated the potential of cell-free fat extract (CEFFE) to promote the healing of diabetic wounds, and annexin A5 (A5) is a crucial anti-inflammatory protein within CEFFE. This study aimed to evaluate the therapeutic potential of A5 in diabetic wounds. Methods: A5 was loaded into GelMA hydrogels and applied to skin wounds of diabetic mice in vivo. The diabetic wounds with the treatment of GelMA-A5 were observed for 14 days and evaluated by histological analysis. Accessment of inflammation regulation were conducted through anti-CD68 staining, anti-CD86 and anti-CD206 staining, and qRT-PCR of wound tissue. In presence of A5, macrophages stimulated by lipopolysaccharide (LPS) in vitro, and detected through qRT-PCR, flow cytometry, and immunocytofluorescence staining. Besides, epithelial cells were co-cultured with A5 for epithelialization regulation by CCK-8 assay and cell migration assay. Results: A5 could promote diabetic wound healing and regulate inflammations by promoting the transition of macrophages from M1 to M2 phenotype. In vitro experiments demonstrated that A5 exerted a significant effect on reducing pro-inflammatory factors and inhibiting the polarization of macrophages from M0 toward M1 phenotype. A5 significantly promoted the migration of epithelial cells. Conclusion: Annexin A5 has a significant impact on the regulation of macrophage inflammation and promotion of epithelialization.

Inflammation and autoimmunity are known as central processes in many skin diseases, including psoriasis. It is therefore important to develop pre-clinical models that describe disease-related aspects to enable testing of pharmaceutical drug candidates and formulations. A widely accepted pre-clinical model of psoriasis is the imiquimod (IMQ)-induced skin inflammation mouse model, where topically applied IMQ provokes local skin inflammation. In this study, we investigated the abundance of a subset of matrix metalloproteinases (MMPs) in skin from mice with IMQ-induced skin inflammation and skin from naïve mice using targeted proteomics. Our findings reveal a significant increase in the abundance of MMP-2, MMP-7, MMP-8, and MMP-13 after treatment with IMQ compared to the control skin, while MMP-3, MMP-9, and MMP-10 were exclusively detected in the IMQ-treated skin. The increased abundance and broader representation of MMPs in the IMQ-treated skin provide valuable insight into the pathophysiology of skin inflammation in the IMQ model, adding to previous studies on cytokine levels using conventional immunochemical methods. Specifically, the changes in the MMP profiles observed in the IMQ-treated skin resemble the MMP patterns found in skin lesions of individuals with psoriasis. Ultimately, the differences in MMP abundance under IMQ-induced inflammation as compared to non-inflamed control skin can be exploited as a model to investigate drug efficacy or performance of drug delivery systems. [Display omitted] • MMP landscape in skin inflammation mouse model analyzed for the first time using MS. • Increase in MMP-2, MMP-7, MMP-8 and MMP-13 abundance in inflamed mouse skin samples. • MMP-3, MMP-9, and MMP-10 were exclusively detected in inflamed mouse skin. • MMP profiles in inflamed mouse skin resemble those in skin of psoriasis patients. [ABSTRACT FROM AUTHOR]

Background: Neurofilament light chain (NfL) has been identified as a biomarker in neuroaxonal injury. Cutaneous nerve injury resulting from inflammation and/or forced scratching may also potentially affect serum NfL (sNfL) levels. Objectives: We aimed to explore the relationship between sNfL levels and the severity of skin inflammation and scratch lesions in patients with pruritus. Methods: In this cross‐sectional pilot study, we measured the sNfL levels of 10 patients with pruritus of different aetiologies, and calculated age‐ and BMI‐adjusted sNfL percentiles based on a normative database consisting of 4532 control individuals. Next, we investigated the relationship between the levels of sNfL and the severity of skin inflammation and scratching injuries in these patients using a newly‐created Skin Inflammation and Scratch Lesions (SISL) score. Results: A positive correlation was observed between sNfL levels and the severity of skin inflammation and scratch lesions as measured by the SISL score (Spearman's rho = 0.70, p = 0.031). When correlated separately, both the "skin inflammation only" and "scratch lesions only" scores correlated positively with sNfL levels (Spearman's rho = 0.68, p = 0.031; Spearman's rho = 0.66, p = 0.041, respectively). Conclusions: sNfL may be a potential biomarker for cutaneous nerve injury associated with skin inflammation and/or scratching. [ABSTRACT FROM AUTHOR]

Abstract Human immortal keratinocyte cells (HaCaT) are induced with UVB to establish an injury model. This model is utilized to investigate whether oat bran fermentation broth (OBF) has a reparative effect on skin inflammation and damage to the skin barrier caused by UVB irradiation. The results show that compared with unfermented oat bran (OB), OBF exhibits higher structural homogeneity, increased molecular weight size, active substances content, and in vitro antioxidant activity. OBF has a scavenging effect on excess reactive oxygen species (ROS) and increases the intracellular levels of antioxidant enzymes. It was found that OBF has a stronger inhibitory effect on the release of inflammatory factors than OB. It increases the synthesis of AQP3 and FLG proteins while decreasing the secretion of KLK-7. OBF can inhibit the transcription level of inflammatory factors by suppressing the JAK/STAT signaling pathway. Safety experiments demonstrate that OBF has a high safety profile. Graphical Abstract

Background and Purpose: Psoriasis results from the interplay of innate and adaptive immunity in the skin. Oroxylin A (OA) has shown anti‐inflammatory effects in various disorders. This study explores oroxylin A potential in treating psoriasis, particularly its impact on type I macrophage (Mφ1) polarization. Experimental Approach: Oroxylin A‐mediated therapeutic effects were evaluated using imiquimod‐induced or IL‐23‐injected psoriatic mice models, followed by proteomics assays to predict potential signalling and targeting proteins. Immunofluorescence and immunoblot assays verified that oroxylin A suppresses NF‐κB signalling in Mφ1 macrophages. Co‐immunoprecipitation and microscale thermophoresis (MST) assays further demonstrated that p62 (sequestosome 1) is the target protein for oroxylin A in macrophages. Oroxylin A‐p62‐mediated suppression of psoriasis was validated in an imiquimod‐induced p62 conditional knockout (cKO) mice model. Key Results: Oroxylin A demonstrated therapeutic efficacy in murine models induced by imiquimod or IL‐23 by attenuating cutaneous inflammation and mitigating Mφ1 polarization via NF‐κB signalling. Proteomics analysis suggested SQSTM1/p62 as a key target, confirmed to interact directly with oroxylin A. Oroxylin A disrupted the p62‐PKCζ interaction by binding to PB1 domain of p62. Its anti‐inflammatory effects were significantly reduced in macrophages from p62 cKO mice compared to the wild‐type (WT) mice in psoriasis model, supporting oroxylin A role in suppressing Mφ1 polarization through its interaction with p62. Conclusion and Implications: Our findings demonstrated oroxylin A suppressed psoriasiform skin inflammation in mouse models by blocking the PKCζ‐p62 interaction, subsequently inhibiting the activation of NF‐κB p65 phosphorylation in macrophages. [ABSTRACT FROM AUTHOR]

Abstract The plasma membrane protein caveolin-1 (CAV-1) regulates signaling by inhibiting a wide range of kinases and other enzymes. Our previous study demonstrated that the downregulation of CAV-1 in psoriatic epidermal cells contributes to inflammation by enhancing JAK/STAT signaling, cell proliferation, and chemokine production. Administration of the CAV-1 scaffolding domain (CSD) peptide suppressed imiquimod (IMQ)-induced psoriasis-like dermatitis. To identify an optimal therapeutic peptide derived from CAV-1, we have compared the efficacy of CSD and subregions of CSD that have been modified to make them water soluble. We refer to these modified peptides as sCSD, sA, sB, and sC. In IMQ-induced psoriasis-like dermatitis, while all four peptides showed major beneficial effects, sB caused the most significant improvements of skin phenotype and number of infiltrating cells, comparable or superior to the effects of sCSD. Phosphorylation of STAT3 was also inhibited by sB. Furthermore, sB suppressed angiogenesis both in vivo in the dermis of IMQ-induced psoriasis mice and in vitro by blocking the ability of conditioned media derived from CAV-1-silenced keratinocytes to inhibit tube formation by HUVEC. In conclusion, sB had similar or greater beneficial effects than sCSD not only by cytokine suppression but by angiogenesis inhibition adding to its ability to target psoriatic inflammation.

ABSTRACT Psoriasis is a chronic inflammatory skin disease characterised by inflammatory cell infiltration, keratinocyte hyperproliferation and increased neovascularization. Despite extensive research, the precise mechanisms underlying psoriasis pathology and treatment strategies remain unclear because of a complex aetiology and disease progression. Hence, in this study, we aimed to identify potential therapeutic targets for psoriasis and explore their effects on disease progression. We observed that G protein‐coupled receptor LGR4 attenuates psoriasis progression. Bioinformatics analysis of publicly available clinical data revealed lower LGR4 expression in the skin lesions of patients with psoriasis than in their non‐lesioned skin. Both in vitro (HaCaT cell) and in vivo (mouse) models confirmed this phenomenon. The Lgr4‐knockout mouse model further confirmed that LGR4 plays a positive role in psoriasis progression. Specifically, Lgr4 knockout promoted the secretion of inflammatory factors, accumulation of local immunocyte infiltration in skin lesions, and keratinocyte proliferation. In conclusion, we demonstrated that LGR4 is critical to limiting psoriasis progression, suggesting that it is a viable target for the clinical management of this skin condition. [ABSTRACT FROM AUTHOR]

Skin homeostasis relies on a delicate balance between host proteases and protease inhibitors along with those secreted from microbial communities, as disruption to this harmony contributes to the pathogenesis of inflammatory skin disorders, including atopic dermatitis and Netherton's syndrome. In addition to being a prominent cause of skin and soft tissue infections, the gram-positive bacterium Staphylococcus aureus is a key player in inflammatory skin conditions due to its array of 10 secreted proteases. Herein we review how S. aureus proteases augment the development of inflammation in skin disorders. These mechanisms include degradation of skin barrier integrity, immune dysregulation and pruritis, and impairment of host defenses. Delineating the diverse roles of S. aureus proteases has the potential to reveal novel therapeutic strategies, such as inhibitors of proteases or their cognate target, as well as neutralizing vaccines to alleviate the burden of inflammatory skin disorders in patients. [ABSTRACT FROM AUTHOR]

Background Psoriasis is a common chronic inflammatory disease with an unclear aetiology. Keratinocytes in psoriasis are susceptible to exogenous triggers that induce inflammatory cell death. Objectives To investigate whether gasdermin E (GSDME)-mediated pyroptosis in keratinocytes contributes to the pathogenesis of psoriasis. Methods Skin samples from patients with psoriasis and from healthy controls were collected to evaluate the expression of GSDME, cleaved caspase-3 and inflammatory factors. We then analysed the data series GSE41662 to further compare the expression of GSDME between lesional and nonlesional skin samples in those with psoriasis. In vivo, a caspase-3 inhibitor and GSDME-deficient mice (Gsdme–/–) were used to block caspase-3/GSDME activation in an imiquimod-induced psoriasis model. Skin inflammation, disease severity and pyroptosis-related proteins were analysed. In vitro , tumour necrosis factor (TNF)-α-induced caspase-3/GSDME-mediated pyroptosis in the HACAT cell line was explored. Results Our analysis of the GSE41662 data series found that GSDME was upregulated in psoriasis lesions vs. normal skin. High levels of inflammatory cytokines such as interleukin (IL)-1β, IL-6 and TNF-α were also found in psoriasis lesions. In mice in the Gsdme –/– and caspase-3 inhibitor groups, the severity of skin inflammation was attenuated and GSDME and cleaved caspase-3 levels decreased after imiquimod treatment. Similarly, IL-1β, IL-6 and TNF-α expression was decreased in the Gsdme –/– and caspase-3 inhibitor groups. In vitro , TNF-α induced HACAT cell pyroptosis through caspase-3/GSDME pathway activation, which was suppressed by blocking caspase-3 or silencing Gsdme. Conclusions Our study provides a novel explanation of TNF-α/caspase-3/GSDME-mediated keratinocyte pyroptosis in the initiation and -acceleration of skin inflammation and the progression of psoriasis. [ABSTRACT FROM AUTHOR]

Atopic dermatitis (AD), a chronic inflammatory skin disease with T cell activation as a key feature, in which Th2 cell–mediated responses play a pivotal role. Regulatory T cells (Treg) are central immune cells that restrict autoimmunity and inflammation in the body. Patients with immune dysregulation, polyendocrinopathy, or enteropathy X-linked syndrome, an immune disease characterized by a deficiency in Treg, develop skin inflammation and allergic disorders, indicating that Treg play a crucial role in the development of allergic skin inflammation. we investigated the underlying mechanisms by which Treg control cutaneous allergic inflammation. An allergic skin inflammation mouse model was constructed using MC903, and Treg-depleted mouse model was constructed using diphtheria toxin. Neutralization of IFN-γ was constructed using anti-mouse-IFN-γ mouse antibody. Neutrophil infiltration was analyzed by flow cytometry and immunohistochemistry. Neutrophil extracellular traps (NETs), a process called NETosis, were detected using immunofluorescence. In vitro neutrophil stimulation and immunocytochemistry was conducted to demonstrate the effect of IFN-γ on NETosis. The depletion of Foxp3+ Treg led to significantly exacerbated AD-like skin inflammation, including increased recruitment of neutrophils and expression of Th1 cytokine IFN-γ. Neutrophil infiltrating in skin of Treg-depleted mice released more NETs than wild type. Neutralization of IFN-γ abolished neutrophil infiltration and NETosis in Treg-depleted mice. Neutrophils stimulated with IFN-γ were more prone to release NETs in vitro. Finally, Foxp3+ Treg control cutaneous allergic inflammation by regulating IFN-γ-driven neutrophilic infiltration and NETosis. Our results highlight the previously underestimated Treg-IFN-γ-neutrophil inflammatory axis. [Display omitted] ● Depletion of Treg exacerbates MC903-induced allergic skin inflammation. ● Neutrophil infiltration and NETosis were detected in Treg-depleted mice during allergic skin inflammation. ● Neutralization of IFN-γ abolished aggravated inflammation in Treg-depleted mice. ● IFN-γ is sufficient to induce NETosis in vitro. [ABSTRACT FROM AUTHOR]

Hyaluronidase possesses the capacity to degrade high-molecular-weight hyaluronic acid into smaller fragments, subsequently initiating a cascade of inflammatory responses and activating dendritic cells. In cases of bacterial infections, substantial quantities of HAase are generated, potentially leading to severe conditions such as cellulitis. Inhibiting hyaluronidase activity may offer anti-inflammatory benefits. Salvia miltiorrhiza Bunge, a traditional Chinese medicine, has anti-inflammatory properties. However, its effects on skin inflammation are not well understood. This study screened and evaluated the active components of S. miltiorrhiza that inhibit skin inflammation, using ligand fishing, enzyme activity assays, drug combination analysis, and molecular docking. By combining magnetic nanomaterials with hyaluronidase functional groups, we immobilized hyaluronidase on magnetic nanomaterials for the first time in the literature. We then utilized an immobilized enzyme to specifically adsorb the ligand; two ligands were identified as salvianolic acid B and rosmarinic acid by HPLC analysis after desorption of the dangling ligands, to complete the rapid screening of potential anti-inflammatory active ingredients in S. miltiorrhiza roots. The median-effect equation and combination index results indicated that their synergistic inhibition of hyaluronidase at a fixed 3:2 ratio was enhanced with increasing concentrations. Kinetic studies revealed that they acted as mixed-type inhibitors of hyaluronidase. Salvianolic acid B had Ki and Kis values of 0.22 and 0.96 μM, respectively, while rosmarinic acid had values of 0.54 and 4.60 μM. Molecular docking revealed that salvianolic acid B had a higher affinity for hyaluronidase than rosmarinic acid. In addition, we observed that a 3:2 combination of SAB and RA significantly decreased the secretion of TNF-α, IL-1, and IL-6 inflammatory cytokines in UVB-irradiated HaCaT cells. These findings identify salvianolic acid B and rosmarinic acid as key components with the potential to inhibit skin inflammation, as found in S. miltiorrhiza. This research is significant for developing skin inflammation treatments. It demonstrates the effectiveness and broad applicability of the magnetic nanoparticle-based ligand fishing approach for screening enzyme inhibitors derived from herbal extracts. [ABSTRACT FROM AUTHOR]

Atopic dermatitis is characterized by scratching and a T H 2-dominated local and systemic response to cutaneously encountered antigens. Dendritic cells (DCs) capture antigens in the skin and rapidly migrate to draining lymph nodes (dLNs) where they drive the differentiation of antigen-specific naive T cells. We sought to determine whether non–T-cell–derived IL-4 acts on skin-derived DCs to promote the T H 2 response to cutaneously encountered antigen and allergic skin inflammation. DCs from dLNs of ovalbumin (OVA)-exposed skin were analyzed by flow cytometry and for their ability to polarize OVA-specific naive CD4+ T cells. Skin inflammation following epicutaneous sensitization of tape-stripped skin was assessed by flow cytometry of skin cells and real-time quantitative PCR of cytokines. Cytokine secretion and antibody levels were evaluated by ELISA. Scratching upregulated IL4 expression in human skin. Similarly, tape stripping caused rapid basophil-dependent upregulation of cutaneous Il4 expression in mouse skin. In vitro treatment of DCs from skin dLNs with IL-4 promoted their capacity to drive T H 2 differentiation. DCs from dLNs of OVA-sensitized skin of Il4 −/− mice and CD11c-CreIl4r flox/− mice, which lack IL-4Rα expression in DCs (DCΔ/Δ ll4ra mice), were impaired in their capacity to drive T H 2 polarization compared with DCs from controls. Importantly, OVA-sensitized DCΔ/Δ ll4ra mice demonstrated impaired allergic skin inflammation and OVA-specific systemic T H 2 response evidenced by reduced T H 2 cytokine secretion by OVA-stimulated splenocytes and lower levels of OVA-specific IgE and IgG1 antibodies, compared with controls. Mechanical skin injury causes basophil-dependent upregulation of cutaneous IL-4. IL-4 acts on skin DCs that capture antigen and migrate to dLNs to promote their capacity for T H 2 polarization and drive allergic skin inflammation. [ABSTRACT FROM AUTHOR]

Acne caused by inflammation of hair follicles and sebaceous glands is a common chronic skin disease. Arctigenin (ATG) is an extract of Arctium lappa L., which has significant anti‐inflammatory effects. However, the effect and mechanism of ATG in cutaneous inflammation mediated by Cutibacterium acnes (C. acnes) has not been fully evaluated. The purpose of this study was to explore the effect and potential mechanism of ATG in the treatment of acne through network pharmacology and experimental confirmation. An acne model was established by injected live C. acnes into living mice and treated with ATG. Our data showed that ATG effectively improved acne induced by live C. acnes, which was confirmed by determining ear swelling rate, estradiol concentration and hematoxylin and eosin (H&E) staining. In addition, ATG inhibited the NLRP3 inflammasome signaling pathway in mice ear tissues and reduced the secretion of pro‐inflammatory cytokines IL‐1β to relieve inflammation. The results of network pharmacology and molecular docking confirmed that ATG can regulate 17β‐Estradiol (E2) levels through targeted to CYP19A1, and finally inhibited skin inflammation. Taken together, our results confirmed that ATG regulated E2 secretion by targeting CYP19A1, thereby inhibiting the NLRP3 inflammasome signaling pathway and improving inflammation levels in acne mice. This study provides a basis for the feasibility of ATG in treating acne in clinical practice. [ABSTRACT FROM AUTHOR]

The article explores the potential of vinpocetine, a phosphodiesterase 1 inhibitor, in treating atopic dermatitis (AD). The study used a mouse model of AD and found that vinpocetine improved symptoms such as skin inflammation and barrier function. It also reduced the infiltration of inflammatory cells and levels of certain cytokines in the skin. The findings suggest that vinpocetine could be a promising therapeutic option for AD, but further research is needed to understand its mechanisms and long-term effects. The research was supported by the Chung-Ang University Research Scholarship Grants in 2022. [Extracted from the article]

Context Derris reticulata Craib. and Glycyrrhiza glabra L., of the Fabaceae, have been used as active components in Thai herbal formulas for the treatment of fever and skin diseases.Objective To evaluate the physicochemical and pharmacological properties of the developed herbal gel formulation containing the combined extract from D. reticulata stem wood and G. glabra root (RGF).Materials and methods The potential of the herbal gel formulation containing RGF (8% w/w) as the active ingredient was studied by evaluating the anti-inflammatory, antioxidant, and anti-Staphylococcus aureus activities using quantitative reverse transcription-polymerase chain reaction assay, spectrophotometric method, and broth microdilution technique, respectively. The reference standards for the biological testing included Nω-nitro-L-arginine (L-NA), ascorbic acid, catechin, and penicillin G. The stability study of the RGF herbal gel was performed by a heating-cooling test (at 45 °C for 24 h and at 4 °C for 24 h/1 cycle; for 6 cycles), and the bioactive marker compounds in the herbal gel were investigated by the HPLC technique.Results RGF showed promising pharmacological effects, particularly on its anti-inflammatory property (IC50 73.86 µg/mL), compared to L-NA (IC50 47.10 µg/mL). The RGF-containing gel demonstrated anti-inflammatory (IC50 3.59 mg/mL) and free radical scavenging effects (IC50 0.05–4.39 mg/mL), whereas it had no anti-S. aureus activity (MIC > 10 mg/mL). The active ingredient in the developed herbal gel significantly inhibited lipopolysaccharide-induced nitric oxide production by downregulating iNOS mRNA levels. The contents of the bioactive markers in the RGF gel (lupinifolin and glabridin) did not change significantly after stability testing.Discussion and conclusions The RGF-containing gel has potential to be further developed as an herbal product for the treatment of skin inflammation.

Autosomal recessive congenital ichthyosis (ARCI) is a genetically heterogeneous disorder with aberrant skin scaling and increased transepidermal water loss (TEWL). Current treatments for ARCI are limited and suboptimal. We present the case of a 27-year-old man with ARCI resulting from a homozygous missense variant in TGM1. RNA-sequencing of lesional skin revealed aberrant Janus kinase–signal transducer and activator of transcription signalling, providing a rationale for innovative treatment with a Janus kinase inhibitor. We prescribed oral tofacitinib (11 mg daily) for 26 weeks. Rapid improvements in erythema and fissuring occurred within the first month. Sustained reductions in 5-D itch scale and Dermatology Life Quality Index scores were also observed. TEWL decreased for the first 10 weeks but increased thereafter. Tofacitinib downregulated inflammatory genes and pathways, while enhancing skin barrier markers. Moreover, transglutaminase 1 distribution was normalized although enzymatic activity remained deficient. This study suggests that oral tofacitinib may be a useful therapy to consider for patients with ARCI. [ABSTRACT FROM AUTHOR]

Medical devices, such as non-invasive ventilation masks, save lives in health care settings but can be a cause of tissue injuries due to the pressure and shear loads on skin and soft tissue. These pressure injuries could be painful for the individual and cause a significant economic impact on healthcare providers. In the etiology of device related pressure ulcers, inflammation plays an important role. However, the exact nature and timing of inflammatory biomarker upregulation is still unknown in the early stages of skin damage. This study aimed to explore the inflammatory profile of vulnerable skin sites following non-invasive mask application on a convenience sample of eleven hospital patients. Seventy-one inflammatory proteins were explored from sebum sampled at the skin surface after oronasal mask application. A multivariate analysis to investigate differences between loaded and control site was conducted, with a protein network analysis used to explore interactions in the early inflammation. The study revealed that 21 cytokines and chemokines were important for the separation between loaded and control site. These proteins were associated with remodeling of tissue, vascular wound healing and/or cell death. [ABSTRACT FROM AUTHOR]

Ferroptosis is considered as an immunogenic type of regulated cell death and associated with the pathogenesis of inflammatory skin diseases. However, the involvement and function of ferroptosis in allergic contact dermatitis (ACD) remains unknown. To explore the role of ferroptosis in ACD. To reveal which type of cells develops ferroptosis in ACD. We detected the key markers of ferroptosis in 1-Chloro-2,4-dinitrochlorobenzene (DNCB)-induced ACD mice model. We applicated ferrostatin-1 (Fer-1) to restrain ferroptosis in ACD mice and then compared the severity of dermatitis and the level of inflammation and ferroptosis in dermis and epidermis, respectively. Keratinocyte-specific Gpx4 conditional knockout (cKO) mice were used to investigate the function of keratinocyte ferroptosis in the development of ACD. Single-cell RNA sequencing was conducted to analyze the affection of Fer-1 on different type of cells in ACD. Ferroptosis was involved in DNCB-induced ACD mice. Ferroptosis activation was more remarkable in dermis rather than in epidermis. Gpx4 cKO mice showed similar severity of skin dermatitis as control mice. Fer-1 alleviated skin inflammation in mice and reduced ferroptosis in neutrophils and CD8+ T cells both of which contribute to development of ACD. Ferroptosis was activated in immune cells, especially neutrophils and CD8+ T cells in DNCB-induced ACD mice. Fer-1 treatment inhibited ferroptosis of neutrophils and CD8+ T cells and relieved skin damage in ACD mice. • Ferroptosis is activated in neutrophils and CD8+ T cells in ACD mice. • Keratinocytes ferroptosis are not contribute to development of ACD. • Topical application of Ferrostatin-1 alleviates skin inflammation of ACD mice. • Ferrostatin-1 suppresses ferroptosis of neutrophils and CD8+ T cells in ACD. [ABSTRACT FROM AUTHOR]

Background Skin barrier dysfunction may both initiate and aggravate skin inflammation. However, the mechanisms involved in the inflammation process remain largely unknown. Objectives We sought to determine how skin barrier dysfunction enhances skin inflammation and molecular mechanisms. Methods Skin barrier defect mice were established by tape stripping or topical use of acetone on wildtype mice, or filaggrin deficiency. RNA-Seq was employed to analyse the differentially expressed genes in mice with skin barrier defects. Primary human keratinocytes were transfected with formylpeptide receptor (FPR)1 or protein kinase R-like endoplasmic reticulum (ER) kinase (PERK) small interfering RNA to examine the effects of these gene targets. The expressions of inflammasome NOD-like receptor (NLR)C4, epidermal barrier genes and inflammatory mediators were evaluated. Results Mechanical (tape stripping), chemical (acetone) or genetic (filaggrin deficiency) barrier disruption in mice amplified the expression of proinflammatory genes, with transcriptomic profiling revealing overexpression of formylpeptide receptor (Fpr1) in the epidermis. Treatment with the FPR1 agonist fMLP in keratinocytes upregulated the expression of the NLRC4 inflammasome and increased interleukin-1β secretion through modulation of ER stress via the PERK-eIF2α-C/EBP homologous protein pathway. The activation of the FPR1-NLRC4 axis was also observed in skin specimens from old healthy individuals with skin barrier defect or elderly mice. Conversely, topical administration with a FPR1 antagonist, or Nlrc4 silencing, led to the normalization of barrier dysfunction and alleviation of inflammatory skin responses in vivo. Conclusions In summary, our findings show that the FPR1-NLRC4 inflammasome axis is activated upon skin barrier disruption and may explain exaggerated inflammatory responses that are observed in disease states characterized by epidermal dysfunction. Pharmacological inhibition of FPR1 or NLRC4 represents a potential therapeutic target. [ABSTRACT FROM AUTHOR]

Psoriasis is a chronic inflammatory skin disease. Topical medicines are the preferred treatment for mild to moderate psoriasis, but the effect of excipients used in semi‐solid preparations on psoriasis‐like skin inflammation is not fully understood. In the present study, we investigated the effect of stearyl alcohol, a commonly used excipient, on imiquimod (IMQ)‐induced psoriasis‐like skin inflammation in mice. Psoriasis‐like skin inflammation was induced by topical IMQ treatment on the back of mice. Skin lesion severity was evaluated by using psoriasis area and severity index (PASI) scores. The skin sections were stained by haematoxylin–eosin and immunohistochemistry. Stearyl alcohol (20% in vaseline) treatment significantly reduced the IMQ‐induced increase of PASI scores and epidermal thickness in mice. IMQ treatment increased the number of Ki67‐ and proliferating cell nuclear antigen (PCNA)‐positive cells in the skin, and the increases were inhibited by stearyl alcohol (20% in vaseline) treatment. Stearyl alcohol treatment (1%, 5%, 10% in vaseline) dose‐dependently ameliorated IMQ‐induced increase of PASI scores and epidermal thickness in mice. Hexadecanol (20% in vaseline), stearic acid (20% in vaseline) and vaseline treatment had no significant effect on IMQ‐induced psoriasis‐like skin inflammation in mice. In conclusion, stearyl alcohol has the effect of improving IMQ‐induced psoriasis‐like skin inflammation in mice. [ABSTRACT FROM AUTHOR]

Abstract Cold atmospheric plasma (CAP) generates reactive oxygen species (ROS) which induce biological effects on living cells. CAP has potential applications in medicine, but its highly reactive nature can lead to adverse skin complications. A noninvasive technique to examine redox changes in skin is needed for monitoring the treatment process. This study was conducted to develop a skin-inflammation model triggered by CAP-derived ROS and to monitor its progression noninvasively by in vivo dynamic nuclear polarization-MRI (DNP-MRI). The model was successfully developed by exposing the skin to both direct and remote modes of CAP. In vivo DNP-MRI imaging revealed faster reduction rates of TEMPOL in plasma-irradiated skin-inflammation areas, particularly in the remote mode plasma-irradiated skin. MRI revealed high-intensity areas in both the superficial and deep layers of the plasma-irradiated skin. The study highlights the potential importance of DNP-MRI in imaging skin-inflammation models and could improve the use of CAP in medical treatments.