Phase 1/2 trials of human bone marrow-derived clonal mesenchymal stem cells for treatment of adults with moderate to severe atopic dermatitis.

BACKGROUND: Mesenchymal stem cells (MSCs) play important roles in therapeutic applications by regulating immune responses. OBJECTIVE: We investigated the safety and efficacy of allogenic human bone marrow-derived clonal MSCs (hcMSCs) in subjects with moderate to severe atopic dermatitis (AD). METHODS: The study included a phase 1 open-label trial followed by a phase 2 randomized, double-blind, placebo-controlled trial that involved 72 subjects with moderate to severe AD. RESULTS: In phase 1, intravenous administration of hcMSCs at 2 doses (1 × 106 and 5 × 105 cells/kg) was safe and well tolerated in 20 subjects. Because there was no difference between the 2 dosage groups (P = .9), it was decided to administer low-dose hcMSCs only for phase 2. In phase 2, subjects receiving 3 weekly intravenous infusions of hcMSCs at 5 × 105 cells/kg showed a higher proportion of an Eczema Area and Severity Index (EASI)-50 response at week 12 compared to the placebo group (P = .038). The differences between groups in the Dermatology Life Quality Index and pruritus numeric rating scale scores were not statistically significant. Most adverse events were mild or moderate and resolved by the end of the study period. CONCLUSIONS: The hcMSC treatment resulted in a significantly higher rate of EASI-50 at 12 weeks compared to the control group in subjects with moderate to severe AD. The safety profile of hcMSC treatment was acceptable. Further larger-scale studies are necessary to confirm these preliminary findings.

Pellino-1 promotes intrinsic activation of skin-resident IL-17A-producing T cells in psoriasis.

BACKGROUND: Psoriasis is a chronically relapsing inflammatory skin disease primarily perpetuated by skin-resident IL-17-producing T (T17) cells. Pellino-1 (Peli1) belongs to a member of E3 ubiquitin ligase mediating immune receptor signaling cascades, including nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB) pathway. OBJECTIVE: We explored the potential role of Peli1 in psoriatic inflammation in the context of skin-resident T17 cells. METHODS: We performed single-cell RNA sequencing of relapsing and resolved psoriatic lesions with analysis for validation data set of psoriasis. Mice with systemic and conditional depletion of Peli1 were generated to evaluate the role of Peli1 in imiquimod-induced psoriasiform dermatitis. Pharmacologic inhibition of Peli1 in human CD4+ T cells and ex vivo human skin cultures was also examined to evaluate its potential therapeutic implications. RESULTS: Single-cell RNA sequencing analysis revealed distinct T-cell subsets in relapsing psoriasis exhibiting highly enriched gene signatures for (1) tissue-resident T cells, (2) T17 cells, and (3) NF-κB signaling pathway including PELI1. Peli1-deficient mice were profoundly protected from psoriasiform dermatitis, with reduced IL-17A production and NF-κB activation in γδ T17 cells. Mice with conditional depletion of Peli1 treated with FTY720 revealed that Peli1 was intrinsically required for the skin-resident T17 cell immune responses. Notably, pharmacologic inhibition of Peli1 significantly ameliorated murine psoriasiform dermatitis and IL-17A production from the stimulated human CD4+ T cells and ex vivo skin explants modeling psoriasis. CONCLUSION: Targeting Peli1 would be a promising therapeutic strategy for psoriasis by limiting skin-resident T17 cell immune responses.

DMOG protects against murine IL-33-induced pulmonary type 2 inflammation through HIF-1 pathway in innate lymphoid cells.

One of the traditional methods of treating allergy is to avoid the allergen, protocol that has long been used in high altitude clinics. It has been hypothesized that the therapeutic effect of high altitude on allergy is due to allergen avoidance, exposure to sunlight and reduced stress. However, the contribution of environmental elements like low oxygen pressure and hypoxia remains underexplored. In this study, we examined the role of hypoxia in the development of type 2 lung inflammation. Mice were administered with papain or recombinant IL-33 intra-nasally to induce type 2 lung inflammation. Some of them were treated additionally with the prolyl hydroxylase (PHD) inhibitor DMOG, which mimics hypoxia. DMOG treatment exhibited an inhibitory effect on the lung inflammation induced by papain or IL-33, operating in a manner independent of T and B cells. The anti-inflammatory effect of DMOG was accompanied by a downregulation of IL-5 and IL-13 in innate lymphoid cells (ILCs), which was abolished in HIF-1α deficient mice. Collectively, our findings suggest that DMOG's modulatory effect on IL-5 and IL-13 operates through the HIF-1 pathway, resulting in a reduction in type 2 lung inflammation. These findings underscore the role of the PHD-HIF pathway in IL-5 and IL-13 expression in lung ILCs and pharmacological inhibition of PHD might be a novel therapeutic candidate for type 2 lung inflammation.

RAB25 coordinates filaggrin-containing keratohyalin granule maturation and affects atopic dermatitis severity.

BACKGROUND: Keratohyalin granules (KHGs) supply the critical epidermal protein constituents such as filaggrin for maintaining skin barrier function during epidermal differentiation; however, their regulating mechanism remains largely unelucidated. METHODS: To investigate the role of Ras-related protein Rab-25 (RAB25) expression in skin disease, we utilized skin specimens of patients with moderate-to-severe atopic dermatitis (AD) and healthy controls. To investigate the susceptibility of Rab25 knockout mice to AD, we established an oxazolone-induced AD model. RESULTS: We investigated the role of RAB25 in KHG maturation and AD. RAB25-deficient mice showed a disrupted stratum corneum along with skin barrier dysfunction, decreased KHG production, and abnormal KHG processing. Consistently, in the human keratinocyte cell line HaCaT, RAB25 co-expressed with filaggrin-containing KHG and RAB25 silencing impaired KHG formation, which was attributable to abnormal actin dynamics. Most importantly, RAB25 expression was severely downregulated in the skin lesions of patients with AD, which was strongly correlated with disease severity scores. CONCLUSIONS: RAB25 coordinates KHG homeostasis by regulating actin dynamics and is critical for epidermal differentiation and the pathophysiology of AD.

Survival of tissue-resident memory T cells requires exogenous lipid uptake and metabolism.

Tissue-resident memory T (TRM) cells persist indefinitely in epithelial barrier tissues and protect the host against pathogens. However, the biological pathways that enable the long-term survival of TRM cells are obscure. Here we show that mouse CD8+ TRM cells generated by viral infection of the skin differentially express high levels of several molecules that mediate lipid uptake and intracellular transport, including fatty-acid-binding proteins 4 and 5 (FABP4 and FABP5). We further show that T-cell-specific deficiency of Fabp4 and Fabp5 (Fabp4/Fabp5) impairs exogenous free fatty acid (FFA) uptake by CD8+ TRM cells and greatly reduces their long-term survival in vivo, while having no effect on the survival of central memory T (TCM) cells in lymph nodes. In vitro, CD8+ TRM cells, but not CD8+ TCM cells, demonstrated increased mitochondrial oxidative metabolism in the presence of exogenous FFAs; this increase was not seen in Fabp4/Fabp5 double-knockout CD8+ TRM cells. The persistence of CD8+ TRM cells in the skin was strongly diminished by inhibition of mitochondrial FFA ß-oxidation in vivo. Moreover, skin CD8+ TRM cells that lacked Fabp4/Fabp5 were less effective at protecting mice from cutaneous viral infection, and lung Fabp4/Fabp5 double-knockout CD8+ TRM cells generated by skin vaccinia virus (VACV) infection were less effective at protecting mice from a lethal pulmonary challenge with VACV. Consistent with the mouse data, increased FABP4 and FABP5 expression and enhanced extracellular FFA uptake were also demonstrated in human CD8+ TRM cells in normal and psoriatic skin. These results suggest that FABP4 and FABP5 have a critical role in the maintenance, longevity and function of CD8+ TRM cells, and suggest that CD8+ TRM cells use exogenous FFAs and their oxidative metabolism to persist in tissue and to mediate protective immunity.

Development of a novel microneedle platform for biomarker assessment of atopic dermatitis patients.

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory skin disease whose pathogenesis, cause, and treatment have been extensively studied. The association of AD with Th2 cytokines is well known; therefore, the analysis of this association is crucial for the diagnosis and treatment of AD. This study aimed to present a new method for measuring protein biomarkers in patients with AD, before and after treatment, using minimally invasive microneedles. MATERIALS AND METHODS: First, hyaluronic acid-loaded microneedle patches (HA-MNs) for skin sample collection were fabricated. Next, after Institutional Review Board approval, 20 patients with AD were recruited and skin samples were taken before and after treatment using four different sampling techniques: (1) tape stripping, (2) hydrocolloid patches, (3) hollow microneedles, and (4) HA-MNs. Lastly, proteins were isolated from the collected samples, and AD-related biomarkers were analyzed by enzyme-linked immunosorbent assay. RESULTS: Proteins were successfully extracted from the skin samples collected by tape stripping, hydrocolloid patches, and HA-MNs, except hollow microneedles. Interleukin (IL)-4, IL-13, and interferon-γ were detected in the HA-MNs only. By comparing the biomarker level correlation before and after treatment and the improvement score of the patients, we observed a significant negative correlation between IL-4 and IL-13 with an improvement in AD symptoms. CONCLUSION: Overall, our results verified that HA-MNs can be used to effectively analyze protein levels of biomarkers from skin metabolites of patients with AD and can be applied to monitor the treatment progress of patients with AD in a minimally invasive manner.

Asivatrep, a TRPV1 antagonist, for the topical treatment of atopic dermatitis: Phase 3, randomized, vehicle-controlled study (CAPTAIN-AD).

BACKGROUND: Asivatrep is a potent and selective antagonist of transient receptor potential vanilloid subfamily V member 1 (TRPV1), which plays an important role in itch and inflammation in atopic dermatitis (AD). OBJECTIVE: This current study aimed to evaluate the efficacy and safety of asivatrep cream in patients with AD. METHODS: For this phase 3 double-blind, vehicle-controlled study, patients aged ≥12 years with mild to moderate AD were enrolled and randomly assigned 2:1 to the 1.0% asivatrep or vehicle group for 8 weeks of twice-daily application (n = 240). The primary end point was the proportion of patients with an Investigator's Global Assessment score (IGA) of 0 or 1 at week 8. Standard safety assessments were conducted. RESULTS: At week 8, significantly more patients in the asivatrep group (36.0%) than in the vehicle group (12.8%) had IGA scores of 0 or 1 (P < .001); significantly more had ≥2 points of improvement on the IGA from baseline score (20.3% vs 7.7%; P = .01). The mean percentage reduction in the Eczema Area and Severity Index (EASI) score was 44.3% for the asivatrep group and 21.4% for the vehicle group at week 8 (P < .001). Significantly more asivatrep-treated patients experienced an improvement of at least 50%, 75%, and 90% on the EASI than the vehicle group. The mean ± SD change in the pruritus visual analog scale score at week 8 was -2.3 ± 2.4 for the asivatrep group and -1.5 ± 2.4 for the vehicle group (P = .02). No significant safety issues were reported. CONCLUSION: Asivatrep improved clinical signs and symptoms of AD and was well tolerated.

Validation of Relationship between Patients' Descriptions of Pruritus and Patient-burden of Chronic Pruritus using Structural Equation Modelling.

Patients with chronic itch describe their pruritus in a wide variety of ways. However, these subjective descriptions are often not taken into consideration by physicians. This study aimed to validate patients' descriptions of pruritus, and to investigate the relationship between various descriptions of pruritus and the patient burden of chronic pruritus by examining the mediating effects of sleep disturbance and sexual dysfunction on patient's quality of life, as predicted by various descriptions of pruritus. Exploratory and confirmatory factor analyses were performed to identify the factor structure measured by 11 descriptions of pruritus. The study then analysed differences in the degree of sleep disturbance, sexual dysfunction, and quality of life deterioration factors using a structural equation modelling method. Using data from 419 patients with chronic pruritus, 11 descriptions of pruritus were classified into 2 groups: (i) sensory pruritus (i.e. stinging, stabbing, burning, painful, formication, throbbing, and cold) that are linked with descriptions of pruritus patterns; and (ii) affective pruritus (i.e. annoying, unbearable, worrisome, and warm) from patient reports of psychological or emotional distress. The study found that affective pruritus decreases patient's quality of life either directly or indirectly through sleep disturbance. In conclusion, clues about a patients' sleep disturbance or poor quality of life can be obtained through their descriptions of pruritus.

Skin-resident natural killer T cells participate in cutaneous allergic inflammation in atopic dermatitis.

BACKGROUND: Natural killer T (NKT) cells are unconventional T cells that bridge innate and adaptive immunity. NKT cells have been implicated in the development of atopic dermatitis (AD). OBJECTIVE: We aimed to investigate the role of NKT cells in AD development, especially in skin. METHODS: Global proteomic and transcriptomic analyses were performed by using skin and blood from human healthy-controls and patients with AD. Levels of CXCR4 and CXCL12 expression in skin NKT cells were analyzed in human AD and mouse AD models. By using parabiosis and intravital imaging, the role of skin CXCR4+ NKT cells was further evaluated in models of mice with AD by using CXCR4-conditionally deficient or CXCL12 transgenic mice. RESULTS: CXCR4 and its cognate ligand CXCL12 were significantly upregulated in the skin of humans with AD by global transcriptomic and proteomic analyses. CXCR4+ NKT cells were enriched in AD skin, and their levels were consistently elevated in our models of mice with AD. Allergen-induced NKT cells participate in cutaneous allergic inflammation. Similar to tissue-resident memory T cells, the predominant skin NKT cells were CXCR4+ and CD69+. Skin-resident NKT cells uniquely expressed CXCR4, unlike NKT cells in the liver, spleen, and lymph nodes. Skin fibroblasts were the main source of CXCL12. CXCR4+ NKT cells preferentially trafficked to CXCL12-rich areas, forming an enriched CXCR4+ tissue-resident NKT cells/CXCL12+ cell cluster that developed in acute and chronic allergic inflammation in our models of mice with AD. CONCLUSIONS: CXCR4+ tissue-resident NKT cells may form a niche that contributes to AD, in which CXCL12 is highly expressed.

Efficacy of transdermal immunotherapy with biodegradable microneedle patches in a murine asthma model.

BACKGROUND: House dust mite (HDM) is a well-known cause of asthma. Allergen-specific immunotherapy (AIT) can only modify the natural course of the disease. Conventional routes of HDM AIT are subcutaneous or sublingual. Subcutaneous immunotherapy (SCIT) has a disadvantage of systemic hypersensitive reaction, and the sublingual immunotherapy has a disadvantage of local allergic reaction and low drug adherence. OBJECTIVE: To overcome the weak points of conventional AIT, we developed a HDM loaded biodegradable microneedle patch (MNP) for transdermal immunotherapy (TDIT). We aim to demonstrate the efficacy of TDIT in murine asthma model triggered by HDM compared with conventional SCIT. METHODS: To make HDM asthma mouse model, 5-week-old BALB/c female mice were sensitized and challenged by intranasal administration of HDM. The mice were divided into 5 groups: sham, asthma, low (10 µg) and high dose (100 µg) SCIT, and TDIT (10 µg). To make HDM loaded MNP, droplet-born air blowing method was used. Airway hyperresponsiveness and allergic inflammation markers were analysed by bronchoalveolar lavage fluid, immunohistochemistry, serum immunoglobulin (Ig) analysis, and lung cytokine assays. RESULTS: Airway hyperresponsiveness was ameliorated by TDIT. Eosinophilic inflammation in bronchoalveolar lavage was improved without adverse reactions. Reduction of Th2 (IL-4, IL-5, and IL-13) cytokines, and HDM-specific IgE, induction of Treg (IL-10, TGF-ß), Th1 (IFN-γ) cytokines were observed. Eosinophilic infiltration, goblet cell hyperplasia, and subepithelial fibrosis were also alleviated by TDIT. These changes were more significant in the TDIT group than in subcutaneous AIT group. CONCLUSION: In conclusion, HDM loaded biodegradable TDIT is a novel treatment option to treat asthma which showed more effectiveness and may have better safety profiles than conventional SCIT.

Validity and reliability of itch assessment scales for chronic pruritus in adults: A prospective multicenter study.

BACKGROUND: Several tools can provide a reliable and accurate evaluation of pruritus, including the visual analog scale (VAS), numeric rating scale (NRS), verbal rating scale (VRS), and multidimensional questionnaires such as the Itch Severity Scale (ISS). However, no single method is considered a gold standard. OBJECTIVE: We evaluated the validity and reliability of VAS, NRS, VRS, and ISS and their correlation with a pruritus-specific quality of life instrument, ItchyQoL. METHODS: A total of 419 patients (215 men and 204 women) with chronic pruritus (mean age, 46.58 years) recorded their pruritus intensity on VAS, NRS, VRS, and ISS. Retest reliability was analyzed in a second assessment 3 hours after the initial assessment. All participants answered ItchyQoL. RESULTS: A strong correlation between VAS, NRS, and VRS was found. ISS showed a low intercorrelation validity with these tools. However, ISS was more strongly correlated with ItchyQoL. The retest reliability scores were similar for VAS, NRS, and VRS but lower than the scores obtained for ISS. LIMITATIONS: Limitations include patient heterogeneity and recall bias. CONCLUSION: The assessment of pruritus is challenging because of the subjective symptoms and the multifactorial nature. Therefore, more studies are needed to determine the best strategy to assess itch intensity.

Chitinase 3-like 1 drives allergic skin inflammation via Th2 immunity and M2 macrophage activation.

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterized by defective skin barrier and Th2 immune responses. Chitinase 3-like 1 (CHI3L1), also known as breast regression protein 39 (BRP-39) in mice and human homologue YKL-40, plays important roles in Th2 inflammation and allergen sensitization. CHI3L1 has been implicated in a variety of diseases including asthma characterized by inflammation, apoptosis and tissue remodelling, but its role in AD remains elusive. OBJECTIVE: The aim of this study was to investigate the role of CHI3L1 in the development and progression of AD. RESULTS: We investigated YKL-40 levels in the serum and skin of AD patients by ELISA and immunofluorescence, respectively. Using a murine model of AD induced by ovalbumin (OVA), we investigated Th2 immune responses, M2 macrophage activation and skin barrier gene expression using wild-type (WT) and BRP-39 null mutant (BRP-39-/- ) mice. YKL-40 level was significantly increased in serum of AD patients. In addition, both mRNA and protein expression levels of BRP-39 were higher in OVA-sensitized WT mice than in control mice. OVA-sensitized BRP-39-/- mice showed decreased epidermal thickness, lower total serum IgE, Th2 cytokine levels and CD4+ effector T cell populations than OVA-sensitized WT mice. Induction of BRP-39 was dominant in dermal macrophages. BRP-39 deficiency was found to be involved in M2 macrophage activation. Consistently, the YKL-40 level in the skin of AD patients was higher than in normal subjects and it was expressed in dermal macrophages. BRP-39 deficiency attenuated dysregulation of skin barrier and tight junction genes. CONCLUSIONS AND CLINICAL RELEVANCE: These findings demonstrate that CHI3L1 mediates the development of AD induced by OVA, affecting Th2 inflammation, M2 macrophage activation and skin barrier function.

A Self-Assembled ATP Probe for Melanoma Cell Imaging.

In this investigation, a new terpyridine metal complex was developed as a probe for selective detection of ATP and imaging of melanoma cells. The probe takes advantage of the ability of the metal complex to be transformed to its imaging competent turn-on state through assembly with ATP.

Staged development of long-lived T-cell receptor αß TH17 resident memory T-cell population to Candida albicans after skin infection.

BACKGROUND: Candida albicans is a dimorphic fungus to which human subjects are exposed early in life, and by adulthood, it is part of the mycobiome of skin and other tissues. Neonatal skin lacks resident memory T (TRM) cells, but in adults the C albicans skin test is a surrogate for immunocompetence. Young adult mice raised under specific pathogen-free conditions are naive to C albicans and have been shown recently to have an immune system resembling that of neonatal human subjects. OBJECTIVE: We studied the evolution of the adaptive cutaneous immune response to Candida species. METHODS: We examined both human skin T cells and the de novo and memory immune responses in a mouse model of C albicans skin infection. RESULTS: In mice the initial IL-17-producing cells after C albicans infection were dermal γδ T cells, but by day 7, αß TH17 effector T cells were predominant. By day 30, the majority of C albicans-reactive IL-17-producing T cells were CD4 TRM cells. Intravital microscopy showed that CD4 effector T cells were recruited to the site of primary infection and were highly motile 10 days after infection. Between 30 and 90 days after infection, these CD4 T cells became increasingly sessile, acquired expression of CD69 and CD103, and localized to the papillary dermis. These established TRM cells produced IL-17 on challenge, whereas motile migratory memory T cells did not. TRM cells rapidly clear an infectious challenge with C albicans more effectively than recirculating T cells, although both populations participate. We found that in normal human skin IL-17-producing CD4+ TRM cells that responded to C albicans in an MHC class II-restricted fashion could be identified readily. CONCLUSIONS: These studies demonstrate that C albicans infection of skin preferentially generates CD4+ IL-17-producing TRM cells, which mediate durable protective immunity.

Successful treatment of lichen amyloidosis accompanied by atopic dermatitis by fractional CO2 laser.

Lichen amyloidosis (LA) is a subtype of primary cutaneous amyloidosis that is presented as persistent, multiple-grouped hyperkeratotic papules usually located on the shins, back, forearms or thighs. The treatment of LA has been considered to be difficult, and of the various methods available, recent studies have reported the efficacy of fractional CO2 lasers. LA may be accompanied by atopic dermatitis (AD) in which the treatment options may be more limited. Herein, we report three cases of LA accompanied by AD treated by a fractional CO2 laser.

Thymic stromal lymphopoietin regulates eosinophil migration via phosphorylation of l-plastin in atopic dermatitis.

Infiltration of eosinophils in atopic dermatitis (AD), which contains inflammatory molecules and cytokines, recruits more inflammatory cells and causes further skin damage. Thymic stromal lymphopoietin (TSLP) is an epithelial cytokine that induces the proinflammatory Th2 immune response and plays an important role in allergic disease. In this study, we aimed to identify a novel protein that regulates TSLP in eosinophils to further understand the role of eosinophils in atopic dermatitis. Using a proteomics approach, we identified the TSLP-inducible protein l-plastin and confirmed upregulation of l-plastin and p-l-plastin in TSLP-treated human eosinophilic leukaemic (EoL-1) cells and in eosinophils from AD patients. Migration assays showed that migration of eosinophils increased when cells were treated with TSLP and when cells were treated with TSLP and an additional cytokine such as interleukin (IL)-3, IL-4, IL-5 or IL-13, when compared to migration of untreated eosinophils. We also confirmed a positive correlation between phosphorylation of l-plastin and an increase in migration of TSLP and cytokine-treated eosinophils. In addition, phosphorylation of l-plastin was sensitive to PKCßII inhibition. Our results suggest that TSLP-induced phosphorylation of l-plastin affects eosinophil migration, which may be mediated by the protein kinase C signalling pathway in atopic dermatitis, thus suggesting p-l-plastin as a potential drug target for eosinophil-targeted allergy therapy.

DAMP molecules S100A9 and S100A8 activated by IL-17A and house-dust mites are increased in atopic dermatitis.

S100A9 and S100A8 are called damage-associated molecular pattern (DAMP) molecules because of their pro-inflammatory properties. Few studies have evaluated S100A9 and S100A8 function as DAMP molecules in atopic dermatitis (AD). We investigated how house-dust mites affect S100A9 and S100A8 expression in Th2 cytokine- and Th17 cytokine-treated keratinocytes, and how secretion of these molecules affects keratinocyte-derived cytokines. Finally, we evaluated expression of these DAMP molecules in AD patients. S100A9 expression and S100A8 expression were strongly induced in IL-17A- and Dermatophagoides (D.) farinae-treated keratinocytes, respectively. Furthermore, co-treatment with D. farinae and IL-17A strongly increased expression of S100A9 and S100A8 compared with D. farinae-Th2 cytokine co-treatment. The IL-33 mRNA level increased in a dose-dependent manner in S100A9-treated keratinocytes, but TSLP expression did not change. S100A8/A9 levels were also higher in the lesional skin and serum of AD patients, and correlated with disease severity. Taken together, S100A9 and S100A8 may be involved in inducing DAMP-mediated inflammation in AD triggered by IL-17A and house-dust mites.