New insights in the immunologic basis of psoriasis

Environmental pollutants and phosphoinositide signaling in autoimmunity

Environmental pollution stands as one of the most critical challenges affecting human health, with an estimated mortality rate linked to pollution-induced non-communicable diseases projected to range from 20% to 25%. These pollutants not only disrupt immune responses but can also trigger immunotoxicity. Phosphoinositide signaling, a pivotal regulator of immune responses, plays a central role in the development of autoimmune diseases and exhibits high sensitivity to environmental stressors. Among these stressors, environmental pollutants have become increasingly prevalent in our society, contributing to the initiation and exacerbation of autoimmune conditions. In this review, we summarize the intricate interplay between phosphoinositide signaling and autoimmune diseases within the context of environmental pollutants and contaminants. We provide an up-to-date overview of stress-induced phosphoinositide signaling, discuss 14 selected examples categorized into three groups of environmental pollutants and their connections to immune diseases, and shed light on the associated phosphoinositide signaling pathways. Through these discussions, this review advances our understanding of how phosphoinositide signaling influences the coordinated immune response to environmental stressors at a biological level. Furthermore, it offers valuable insights into potential research directions and therapeutic targets aimed at mitigating the impact of environmental pollutants on the pathogenesis of autoimmune diseases. SYNOPSIS: Phosphoinositide signaling at the intersection of environmental pollutants and autoimmunity provides novel insights for managing autoimmune diseases aggravated by pollutants.

Tripterygium wilfordii Hook. F. and Its Extracts for Psoriasis: Efficacy and Mechanism

Psoriasis is an inflammatory autoimmune skin condition that is clinically marked by chronic erythema and scaling. The traditional Chinese herb Tripterygium wilfordii Hook. F. (TwHF) is commonly used in the treatment of immune-related skin illnesses, such as psoriasis. In clinical studies, PASI (Psoriasis Area and Severity Index) were dramatically decreased by TwHF and its extracts. Their benefits for psoriasis also include relief from psoriasis symptoms such as itching, dryness, overall lesion scores and quality of life. And the pathological mechanisms include anti-inflammation, immunomodulation and potentially signaling pathway modulations, which are achieved by modulating type-3 inflammatory cytokines including IL-22, IL-23, and IL-17 as well as immune cells like Th17 lymphocytes, γδT cells, and interfering with IFN-SOCS1, NF-κB and IL- 36α signaling pathways. TwHF and its extracts may cause various adverse drug reactions, such as gastrointestinal responses, aberrant hepatocytes, reproductive issues, and liver function impairment, but at adequate doses, they are regarded as an alternative therapy for the treatment of psoriasis. In this review, the effectiveness and mechanisms of TwHF and its extracts in psoriasis treatment are elucidated.

miRNA-559 and MTDH as possible diagnostic markers of psoriasis: Role of PTEN/AKT/FOXO pathway in disease pathogenesis

Psoriasis is a persistent, inflammatory, autoimmune skin disorder which can be elicited by genetic and environmental factors. Several microRNAs (miRNAs) that are abnormally expressed in psoriasis have emerged as an interesting candidate in psoriasis pathogenesis. However, the expression profile and function of miRNA-559, and its direct target metadherin (MTDH), in psoriasis need to be further illuminated. This study intended to assess miRNA-559 and MTDH levels in skin and sera of psoriatic patients and to investigate their clinical significance in an attempt for developing novel distinct tools for early diagnosis of psoriasis. Moreover, this study aimed at exploring participation of miRNA-559 in regulating MTDH/PTEN/AKT pathway in psoriasis. Expression levels of miRNA-559, AKT, FOXO1 and PTEN were measured by real-time qRT-PCR, whereas MTDH and p27 levels were assessed by ELISA in lesional, non-lesional tissues and serum of 20 psoriatic patients and 20 matching controls. Correlation study was conducted between different parameters. The diagnostic performance of miRNA-559 and MTDH in psoriasis was estimated by receiver operating characteristic (ROC) curve analysis. Expression of miRNA-559 in psoriatic patients was significantly downregulated in both lesional tissues and serum as compared to controls. Conversely, MTDH protein level showed significant increase in both tissues and serum of psoriatic patients and was inversely correlated with miRNA-559 level. Meanwhile, levels of PTEN, AKT and FOXO1 were dramatically changed in psoriatic patients compared to controls. Furthermore, serum miRNA-559 and MTDH displayed comparable diagnostic accuracy in discriminating psoriatic patients from controls. Yet, miRNA-559 demonstrated superior diagnostic performance than MTDH in psoriasis diagnosis. Together, the current findings provide the first suggestion of a new mechanism by which downregulation of miRNA-559 might induce proliferation in psoriasis through modulating PTEN/AKT/FOXO1 pathway by positive regulation of MTDH. Thus, miRNA-559 and MTDH might be proposed as promising diagnostic biomarkers of psoriasis.

Current and emerging prospects in the psoriatic treatment

Psoriasis is an autoimmune chronic disorder that causes inflammation and a scaly epidermis. The exact pathogenesis of the disease is not known yet. According to the studies, psoriasis is considered an immune-mediated disease. Until now it is believed that genetic and environmental factors are responsible for the disease. There are many comorbidities associated with psoriasis which increases difficulties as patients in some cases get addicted to drugs, alcohol, and smoking which reduces their quality of life. The patient may face social ignorance or suicidal thoughts which may arise in the patient's mind. Due to the undefined trigger of the disease, the treatment is not fully established but by considering the severe impact of the disease researchers are focusing on novel approaches for successful treatment. which has succeeded to a large extent. Here we review pathogenesis, problems faced by psoriatic patients, the need for the development of new treatments over conventional therapies, and the history of psoriatic treatments. We thoroughly focus on emerging treatments like biologics, biosimilars, and small molecules which are now showing more efficacy and safety than conventional treatments. Also, this review article discusses novel approaches which are now in research such as drug repurposing, treatment by stimulation of the vagus nerve, regulation of microbiota, and autophagy for improving disease conditions.

The Association Between Forkhead Box Class O3A Gene Polymorphism and Psoriasis and Its Relationship with Psoriasis Severity

BACKGROUND

Psoriasis vulgaris is a chronic, relapsing, inflammatory disorder marked by an intensified immune response. The role of immunogenetics in psoriasis is still poorly understood; however, experts agree that its expression depends on proinflammatory cytokines.Forkhead box class O3A (FOXO3a), a transcription factor, plays a crucial role in intercellular regulation, oxidative stress, deoxyribonucleic acid (DNA) repair, and cell death.

OBJECTIVE

The objective of this study was to investigate the role of FOXO3a genetic polymorphism as a risk factor for psoriasis vulgaris and assess its possible relationship with disease severity.

METHODS

A comparative case-control study included 53 patients with psoriasis and 41 matched healthy controls. We measured serum FOXO3a levels and used the PCR-RFLEP technique to detect FOXO3a genetic polymorphism (rs13217795) in both groups.

RESULTS

Our results revealed significantly higher serum FOXO3a levels in the psoriasis group compared to the control group (p≤0.001). Serum FOXO3a levels were significantly higher in patients with severe psoriasis than in those with mild-to-moderate disease. FOXO3a genotypes found homozygous mutant genotype (TT) was substantially more frequent in the psoriasis group than in the control group. Furthermore, the T allele was more frequent in the psoriasis group than in the control group.

CONCLUSION

The study indicates that rs13217795 polymorphism of the FOXO3a gene is strongly associated with susceptibility to psoriasis. Also, the serum level of FOXO3a is significantly higher in patients with severe psoriasis, compared to patients with mild-to-moderate psoriasis. This finding could be an area of future targeted therapy.

Gingiva-Derived Mesenchymal Stem Cells Attenuate Imiquimod- (IMQ-) Induced Murine Psoriasis-Like Skin Inflammation

Human gingiva-derived mesenchymal stem cells (GMSCs) are isolated from the gingival propria with promising regenerative, immunomodulatory, and anti-inflammatory properties. Recently, several studies, including ours, have found that GMSCs have the therapeutic potentials of nerve regeneration and skin disorders in various types such as the cell itself, cell-free conditioned medium, or extracellular vesicles (EVs). However, the mechanobiological behavior of GMSCs is closely related to the culture conditions. Therefore, the purpose of this study was to evaluate the function of human GMSCs on imiquimod- (IMQ-) induced murine psoriasis-like skin inflammation in two-dimensional (2D) and three-dimensional (3D) culture conditions. Here, we isolated and characterized GMSCs in 2D and 3D culture conditions and found that GMSCs in 2D and 3D infusion can significantly ameliorate the IMQ-induced murine psoriasis-like skin inflammation, reduce the levels of Th1- and Th17-related cytokines IFN-γ, TNF-α, IL-6, IL-17A, IL-17F, IL-21, and IL-22, and upregulate the percentage of spleen CD25+CD3+ T cells while downregulate the percentage of spleen IL-17+CD3+ T cells. In summary, our novel findings reveal that GMSCs in 2D and 3D infusion may possess therapeutic effects in the treatment of psoriasis.

Break on through: The role of innate immunity and barrier defence in atopic dermatitis and psoriasis

The human skin can be affected by a multitude of diseases including inflammatory conditions such as atopic dermatitis and psoriasis. Here, we describe how skin barrier integrity and immunity become dysregulated during these two most common inflammatory skin conditions. We summarise recent advances made in the field of the skin innate immune system and its interaction with adaptive immunity. We review gene variants associated with atopic dermatitis and psoriasis that affect innate immune mechanisms and skin barrier integrity. Finally, we discuss how current and future therapies may affect innate immune responses and skin barrier integrity in a generalized or more targeted approach in order to ameliorate disease in patients.

Updated Perspectives on Keratinocytes and Psoriasis: Keratinocytes are More Than Innocent Bystanders

Psoriasis is a complex disease triggered by genetic, immunologic, and environmental stimuli. Many genes have been linked to psoriasis, like the psoriasis susceptibility genes, some of which are critical in keratinocyte biology and epidermal barrier function. Still, the exact pathogenesis of psoriasis is unknown. In the disease, the balance between the proliferative and differentiative processes of keratinocytes becomes altered. Multiple studies have highlighted the role of dysregulated immune cells in provoking the inflammatory responses seen in psoriasis. In addition to immune cells, accumulating evidence shows that keratinocytes are involved in psoriasis pathogenesis, as discussed in this review. Although certain immune cell-derived factors stimulate keratinocyte hyperproliferation, activated keratinocytes can also produce anti-microbial peptides, cytokines, and chemokines that can promote their proliferation, as well as recruit immune cells to help initiate and reinforce inflammatory feedback loops. Psoriatic keratinocytes also show intrinsic differences from normal keratinocytes even after removal from the in vivo inflammatory environment; thus, psoriatic keratinocytes have been found to exhibit abnormal calcium metabolism and possible epigenetic changes that contribute to psoriasis. The Koebner phenomenon, in which injury promotes the development of psoriatic lesions, also provides evidence for keratinocytes' contributions to disease pathogenesis. Furthermore, transgenic mouse studies have confirmed the importance of keratinocytes in the etiology of psoriasis. Finally, in addition to immune cells and keratinocytes, data in the literature support roles for other cell types, tissues, and systems in psoriasis development. These other contributors are all potential targets for therapies, suggesting the importance of a holistic approach when treating psoriasis.

Interactions of the Neuro‒Immune‒Stromal Triad in Itch

This review focuses on recent advances in understanding the mechanisms involved in itch signaling in the skin and how these new findings fit into the wider picture of the expression of itch mediators and their receptors in the dermal layer. Because at present studies mostly concentrate on single cellular compartments (e.g., neural alone), we suggest that they may miss important interactions with other compartments. Therefore, to fully appreciate pruritus, we propose that studies should consider (e.g., using transcriptomic information) signal transmission within the entire neuro‒immune‒stromal triad.

Oxyresveratrol Inhibits TNF-α-Stimulated Cell Proliferation in Human Immortalized Keratinocytes (HaCaT) by Suppressing AKT Activation

Psoriasis is a complex inflammatory disease characterized by hyperproliferative keratinocyte caused by active PI3K/AKT signaling. TNF-α concentrated in the psoriatic lesions stimulates AKT activation. We previously discovered that oxyresveratrol inhibited inflammation via suppressing AKT phosphorylation, therefore oxyresveratrol may possess a conserved property to block AKT activation and proliferation in keratinocyte in response to TNF-α. Our current study proved that oxyresveratrol exhibited potent anti-proliferative effects against TNF-α. These effects are explained by the findings that oxyresveratrol could potentially inhibit TNF-α-stimulated AKT and GSK3-β activation in a dose-dependent manner, and its inhibitory pattern was comparable to that of a specific PI3K inhibitor. Results from immunofluorescence supported that oxyresveratrol effectively inhibited AKT and GSK3-β activation in individual cells upon TNF-α stimulation. Furthermore, functional assay confirmed that oxyresveratrol repressed the expansion of the HaCaT colony over 3 days, and this was caused by the ability of oxyresveratrol to induce cell cycle arrest at S and G2/M phases and the reduction in the expression of a proliferative marker (Ki-67) and a survival marker (MCL-1). Given the importance of TNF-α and the PI3K/AKT pathway in the psoriatic phenotype, we anticipate that oxyresveratrol, which targets the TNF-α-stimulated PI3K/AKT pathway, would represent a promising psoriasis therapy in the near future.

Maternal and neonatal outcomes of births to women with psoriasis: a population-based cohort of 13 million births

PURPOSE

Psoriasis is a common auto-immune disease affecting the skin and joints for which the current literature remains limited and contradictory in the context of pregnancy. The purpose of our study was to evaluate the association between psoriasis in pregnancy and maternal and newborn outcomes.

METHODS

A population based retrospective cohort study was conducted using the 1999-2015 United States' Healthcare Cost and Utilization Project Nationwide Inpatient Sample. ICD-9 codes were used to identify delivery admissions to women with or without psoriasis, as well as maternal and fetal outcomes. Adjusting for baseline characteristics, multivariate logistic regression models were performed to estimate the effects of psoriasis on maternal and newborn outcomes.

RESULTS

The cohort consisted of 3737 women with psoriasis, among a total of 13,792,544 pregnancy admissions in US hospitals between the years 1999 and 2015, for a period prevalence of 27.1 cases per 100,000 pregnant women. Psoriasis was associated with preeclampsia, OR 1.4 (95% CI 1.2-1.6), gestational diabetes, 1.27 (1.13-1.42), myocardial infarction, 13.4 (3.3-54.6), chorioamnionitis, 1.3 (1.0-1.6), delivery by cesarean section, 1.2 (1.1-1.3), anemia, 1.74 (1.18-2.57), and requiring blood transfusions, 1.4 (1.0-1.8). Their newborns were at higher risk of being born preterm, 1.2 (1.1-1.4), congenital anomalies, 1.7 (1.2-2.4), and intra-uterine growth restriction, 1.5 (1.2-1.7).

CONCLUSION

Women with psoriasis and their newborns appear more prone to adverse outcomes of pregnancy. It would be prudent for these women to be followed closely during pregnancy by their obstetrical caregiver and dermatologist. Further investigation is warranted regarding the management of psoriasis during pregnancy.

Effectiveness and safety of guselkumab for the treatment of psoriasis in real-world settings at 24 weeks: A retrospective, observational, multicentre study by the Spanish Psoriasis Group

BACKGROUND

Data on the effectiveness and safety of a drug in real-world clinical practice complement the evidence from clinical trials, which are carried out in a different setting. Little has been published on the effectiveness and safety of guselkumab in the treatment of psoriasis in clinical practice.

OBJECTIVES

To assess the effectiveness and safety of guselkumab at 24 weeks in patients with moderate to severe plaque psoriasis in routine clinical practice.

METHODS

Retrospective, multicentre study of adult patients with moderate to severe plaque psoriasis treated with guselkumab for at least 24 weeks in Spain.

RESULTS

We studied 343 patients, 249 of whom were followed for 24 weeks. By week 24, the mean (SD) Psoriasis Area and Severity Index (PASI) had decreased from 11.1 (7.3) to 1.7 (2.8) (-9.3; [-10.2;-8.4]), 85.9% of the patients had achieved PASI score of 4 or less and 77.9% a PASI score of 2 or less. In terms of relative PASI response, 59.4% of the patients achieved a PASI-90 response and 49.0% a PASI-100 response. On multivariate analysis, 2 factors reduced the probability of a PASI of 2 or less at 24 weeks: a BMI ≥30 (OR, 0.44; 95% CI, 0.22-0.88) and a greater previous exposure to biologic therapy (OR, 0.69; 95% CI, 0.56-0.84]). Adverse events were rare (9.9%) and led to withdrawal from treatment in only 9 patients (2.6%) by the end of the follow-up period.

CONCLUSION

The results of this study confirm the high efficacy and safety of guselkumab indicated by the clinical trial data. In clinical practice, the absolute PASI score appears to be a better marker of response to treatment than the relative value.

Glycerol Improves Skin Lesion Development in the Imiquimod Mouse Model of Psoriasis: Experimental Confirmation of Anecdotal Reports from Patients with Psoriasis

Glycerol is used in many skin care products because it improves skin function. Anecdotal reports by patients on the National Psoriasis Foundation website also suggest that glycerol may be helpful for the treatment of psoriasis, although to date no experimental data confirm this idea. Glycerol entry into epidermal keratinocytes is facilitated by aquaglyceroporins like aquaporin-3 (AQP3), and its conversion to phosphatidylglycerol, a lipid messenger that promotes keratinocyte differentiation, requires the lipid-metabolizing enzyme phospholipase-D2 (PLD2). To evaluate whether glycerol inhibits inflammation and psoriasiform lesion development in the imiquimod (IMQ)-induced mouse model of psoriasis, glycerol’s effect on psoriasiform skin lesions was determined in IMQ-treated wild-type and PLD2 knockout mice, with glycerol provided either in drinking water or applied topically. Psoriasis area and severity index, ear thickness and ear biopsy weight, epidermal thickness, and inflammatory markers were quantified. Topical and oral glycerol ameliorated psoriasiform lesion development in wild-type mice. Topical glycerol appeared to act as an emollient to induce beneficial effects, since even in PLD2 knockout mice topical glycerol application improved skin lesions. In contrast, the beneficial effects of oral glycerol required PLD2, with no improvement in psoriasiform lesions observed in PLD2 knockout mice. Our findings suggest that the ability of oral glycerol to improve psoriasiform lesions requires its PLD2-mediated conversion to phosphatidylglycerol, consistent with our previous report that phosphatidylglycerol itself improves psoriasiform lesions in this model. Our data also support anecdotal evidence that glycerol can ameliorate psoriasis symptoms and therefore might be a useful therapy alone or in conjunction with other treatments.

Effect of Baricitinib on TPA-induced psoriasis like skin inflammation

Psoriasis is a chronic inflammatory disorder of the skin and is characterized by hyper-dividing keratinocytes. This hyper-proliferation of keratinocytes is due to the high level of inflammatory cytokines. In this study, we evaluated the effect of topically applied Baricitinib, JAK1/2 inhibitor on chronic 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced psoriasis model in mice. To our knowledge, this is the first report evaluating the topical route of administration of Baricitinib in the context of psoriasis in vivo. TPA-induced inflammation was induced by the topical application of TPA in both ears. Thirty minutes before the application of TPA, the inner and outer surface of each ear was treated with Baricitinib for 6 days. Topical application of Baricitinib inhibited the expression of inflammation markers up-regulated by TPA. Besides, Baricitinib substantially reduced ear swelling, infiltration of leukocytes, the proliferation of epidermal cells, and angiogenesis of the dermal layer. The results suggest that Baricitinib significantly reduced phosphorylation of STAT3 and STAT1 levels in turn attenuating the downstream expression of inflammatory cytokines. Collectively, these results suggest that Baricitinib can be a potential therapeutic through topical route for psoriasis progresses.

The PI3K/Akt Pathway: Emerging Roles in Skin Homeostasis and a Group of Non-Malignant Skin Disorders

The phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway regulates cell proliferation, differentiation, and migration, along with angiogenesis and metabolism. Additionally, it could mediate skin development and homeostasis. There is much evidence to suggest that dysregulation of PI3K/Akt pathway is frequently associated with several human cutaneous malignancies like malignant melanoma (MM), basal cell carcinoma (BCC), and cutaneous squamous cell carcinoma (SCC), as well as their poor outcomes. Nevertheless, emerging roles of PI3K/Akt pathway cascade in a group of common non-malignant skin disorders including acne and psoriasis, among others, have been recognized. The enhanced understanding of dysfunction of PI3K/Akt pathway in patients with these non-malignant disorders has offered a solid foundation for the progress of updated therapeutic targets. This article reviews the latest advances in the roles of PI3K/Akt pathway and their targets in the skin homeostasis and progression of a wide range of non-malignant skin disorders and describes the current progress in preclinical and clinical researches on the involvement of PI3K/Akt pathway targeted therapies.

Sortilin regulates keratinocyte proliferation and apoptosis through the PI3K-AKT signaling pathway

Sortilin is found to regulate proliferation and death of different cells, while its role in regulating keratinocyte proliferation and apoptosis is still unknown. In this study, we found that sortilin levels significantly increased in psoriasis patients, and sortilin suppression eliminated the proliferation of HaCaT cells induced by M5 cocktail solution and enhanced the levels of cleaved caspase 3 protein and the Bax/Bcl-2 ratio; however, levels of p-PI3K and p-AKT were decreased. In addition, sortilin silencing remitted the characteristic changes associated with psoriasis-like skin lesions. In summary, suppressed sortilin expression helped inhibit keratinocyte proliferation in HaCaT cells by inactivating PI3K/AKT signaling, which provides a new target for the therapy of psoriasis.

Mass cytometry analysis of blood immune cells from psoriasis patients on biological therapy

Psoriasis is a chronic immune-mediated skin disease accompanied by systemic inflammation and comorbidities. We analyzed peripheral blood mononuclear cells (PBMCs) in the search for immune signatures and biomarkers related to psoriasis severity and treatment effect. Thirty-two patients with psoriasis and 10 matched healthy controls were included. PBMCs were collected before and after initiation of anti-TNF, anti-IL-17 or anti-IL-12/23 treatment and analyzed utilizing 26-parameter mass cytometry. The number of circulating Th17, Th22, Th9, and cytotoxic T cells were increased in severe psoriasis. Intracellular pp38 and pERK in T helper cells were associated with disease severity. Differences between responders and nonresponders regarding cell composition and intracellular signaling were identifiable already at inclusion. Biological treatment induced memory cells, restored inhibitory PD-1 function of T cells, and reduced a potential pro-atherogenic profile in monocytes. In conclusion, these results indicate amelioration of systemic inflammation in psoriasis after biological treatment. Such broad immune profiling may enable prospective stratification of patients regarding future treatment response. Successful early intervention may lead to a healthier trajectory with favorable implications on later comorbidities.

Interleukin-17A affects extracellular vesicles release and cargo in human keratinocytes

Psoriasis is a chronic inflammatory systemic disease caused by deregulation of the interleukin-23/-17 axis that allows the activation of Th17 lymphocytes and the reprogramming of keratinocytes proliferative response, thereby inducing the secretion of cyto-/chemokines and antimicrobial peptides. Beside cell-to-cell contacts and release of cytokines, hormones and second messengers, cells communicate each other through the release of extracellular vesicles containing DNA, RNA, microRNAs and proteins. It has been reported the alteration of extracellular vesicles trafficking in several diseases, but there is scarce evidence of the involvement of extracellular vesicles trafficking in the pathogenesis of psoriasis. The main goal of the study was to characterize the release, the cargo content and the capacity to transfer bioactive molecules of extracellular vesicles produced by keratinocytes following recombinant IL-17A treatment if compared to untreated keratinocytes. A combined approach of standard ultracentrifugation, RNA isolation and real-time RT-PCR techniques was used to characterize extracellular vesicles cargo. Flow cytometry was used to quantitatively and qualitatively analyse extracellular vesicles and to evaluate cell-to-cell extracellular vesicles transfer. We report that the treatment of human keratinocytes with IL-17A significantly modifies the extracellular vesicles cargo and release. Vesicles from IL-17A-treated cells display a specific pattern of mRNA which is undid by IL-17A neutralization. Extracellular vesicles are taken up by acceptor cells irrespective of their content but only those derived from IL-17A-treated cells enable recipient cells to express psoriasis-associated mRNA. The results imply a role of extracellular vesicles in amplifying the pro-inflammatory cascade induced in keratinocyte by pro-psoriatic cytokines.

Association of Pathogenic Th17 Cells with the Disease Severity and Its Potential Implication for Biological Treatment Selection in Psoriasis Patients

Psoriasis is an inflammatory autoimmune disease characterized by cutaneous lesions in plaques. It has been proposed that the immune response has a key role in the disease progression. Particularly, the Th17 cells through IL-17 can contribute to maintain the inflammatory process. The pathogenic Th17 phenotype has been described in human diseases and associated with high severity in inflammatory experimental models. However, it is not clear if the pathogenic phenotype could be present in the skin and peripheral blood as well as its possible association to severity in psoriasis. In the lesional skin, we found high infiltration of Th17 cells and the pathogenic phenotype, finding a correlation between the frequency of Th17 cells and the Psoriasis Area and Severity Index (PASI) score. In peripheral blood, we observed a pool of Th17 lymphocytes with potential to acquire pathogenic features. Interestingly, the percentage of pathogenic Th17 cells (CD4⁺ RORγt⁺ IFN-γ⁺) correlates with disease severity. Moreover, we distinguished three groups of patients based on their IL-17/IFN-γ production by Th17 lymphocytes, which seems to be related with a dynamic or stable potential to express these cytokines. Remarkably, we evaluated the cytokine production by Th17 cells as an immunological marker for the adequate selection of biologic therapy. We found that patients analyzed by this immunological approach and treated with antibodies against IL-17 and TNFα showed great improvement depicted by reduction in PASI and Dermatology Life Quality Index (DLQI) score as well as the percentage of Body Surface Area (BSA). Altogether, our results highlight the importance of the assessment of the pathogenic phenotype in Th17 cells as an immune personalized analysis with the potential to support the therapy choice in the clinical practice.

Role of biomarkers and effect of FIP-fve in acute and chronic animal asthma models

BACKGROUND

Asthma is a consequence of complex gene-environment interactions. Exploring the heterogeneity of asthma in different stages is contributing to our understanding of its pathogenesis and the development of new therapeutic strategies, especially in severe cases.

OBJECTIVE

This study aimed to further understand the relationship between manifestations of acute and chronic asthma and various endotypes, and explore the severity of lung inflammation, cell types, cytokine/chemokine differences, and the effects of FIP-fve.

MATERIALS AND METHODS

Acute and chronic OVA-sensitization mouse asthma models, based on our previously published method, were used and FIP-fve was used to evaluate the effect on these two models. BALF cytokines/chemokines were detected according to the manufacturer's protocol.

RESULTS

Seventeen cytokine/chemokine secretions were higher in the chronic stage than in the acute stage. Whether in acute stage or chronic stage, the FIP-fve treatment groups had reduced airway hyperresponsiveness, infiltration of airway inflammatory cells, secretion of cytokines, chemokines by Th2 cells, and TNF-α, IL-8, IL-17, CXCL-1, CXCL-10, CCL-17, and CCL-22, and it was also found that the Treg cell cytokine IL-10 had increased significantly. PCA (Principal Component Analysis) was also used to compare statistics and laboratory data to find the important biomarkers in different stages and after treatment with FIP-fve.

CONCLUSIONS

There are many different immune responses in the different stages of the asthma process. Drug treatment at the appropriate times might help reduce the worsening of asthma.

A spray containing extracts of oat plantlets and Uncaria tomentosa relieves pain associated with chronic inflammatory skin diseases and dermatological procedures

BACKGROUND

Inflammation from skin conditions such as psoriasis, eczema-like atopic dermatitis (AD) and hand eczema (HE) and following dermatological procedures (post-acts) can result in intense itching and cutaneous pain. Dermo-cosmetics containing plant extracts have been shown to reduce or alleviate these symptoms.

OBJECTIVES

Assessment of the tolerability and efficacy of a spray containing Rhealba\xAE Oat plantlets and Uncaria tomentosa extracts in adults and children with inflammatory skin diseases and after dermatological procedures.

METHODS

Data from five open label studies were analysed (Study 1: adults with AD; Study 2: children with AD; Study 3: adults with psoriasis; Study 4: adults with HE; Study 5: adults who had undergone a dermatological procedure: laser, intense pulsed light, glycolic acid peeling, photodynamic therapy or cryotherapy procedure). In all studies, subjects could use the test product up to six times per day for symptom relief. Physical and functional signs of inflammation, treatment-emergent adverse events (TEAEs), soothing effect, changes in quality of life, cutaneous pain and cosmetic acceptability were compared pre- and postapplication.

RESULTS

A total of 176 subjects were enrolled across the five studies. Overall, investigators judged the dermatological tolerance of the test product containing Rhealba\xAE Oat plantlets extract and Uncaria tomentosa as good to excellent. All studies showed significant improvements in physical signs, reduction in itching and feeling of pain (P < 0.05). The soothing effect was evident after the first application. TEAEs were mostly mild, transient and occurred within the first few days of treatment. The majority of subjects reported improved QoL across the studies.

CONCLUSIONS

The dermo-cosmetic spray containing Rhealba\xAE Oat plantlets extract and U. tomentosa was well tolerated and efficacious in providing relief of symptoms associated with cutaneous pain from inflammatory skin diseases and following dermatological procedures; however, further studies are needed to rule out alternative explanations of symptom reduction such as natural history and response biases.

A peptide derived from phage-display limits psoriasis-like lesions in mice

BACKGROUND

Psoriasis is a pro-inflammatory disease with unknown etiology, that is characterized by skin inflammation and keratinocytes hyperproliferation. Specific inhibition of inflammation has shown positive effects avoiding the progression of the psoriatic lesions in different animal models of the disease, turning this strategy as a remarkable therapeutic alternative.

OBJECTIVE

To screen the effectiveness of a novel IFN-α/β signalling inhibitor in the development reduction of skin lesions in IMQ and TPA mice models of psoriasis.

METHODS

We used a Phage-peptide library for the screening of a peptide with inhibitory effects on the development of psoriasis-like lesions in mice. To evaluate the in vivo effect of the phage-peptides (Phpep3D) and the derived peptide (Pep3D), we administered Phpep3D or Pep3D intradermally in mice with imiquimod (IMQ)-induced psoriasis and 12-O-tetradecanoyl phorbol-13-acetate (TPA)-induced psoriasis. We scored the lesions, and we determined the number of neutrophils and the production of some pro-inflammatory cytokines in the lesions.

RESULTS

In this work, we describe how the Ph3pepD and Pep3D reduced skin thickness, redness, and acanthosis despite the presence of the psoriasis inducers, IMQ or TPA. We also found that Pep3D reduced the number of GR1+ infiltrated cells and decreased the production of IL-17A and TNFα in the psoriatic skin of mice. In-silico, docking analysis showed that Pep3D may interact with the interferon-alpha receptor, but further analyses should be performed to uncover the mechanism of action of this peptide.

CONCLUSION

Our results suggest that Pep3D could be used as a new treatment for psoriasis.

Transglutaminase 3 Reduces the Severity of Psoriasis in Imiquimod-Treated Mouse Skin

Four transglutaminase (TG) isoforms have been detected in epidermal keratinocytes: TG1, TG2, TG3, and TG5. Except for TG1 and TG3, their contribution to keratinocyte development and structure remains undefined. In this paper, we focused on the roles of TG2 and TG3 in imiquimod-induced psoriasis in mouse skin. We evaluated the severity of psoriasis markers in the skin of imiquimod-treated TG3 null and TG2 null mice. Our results showed that compromised TG3KO mouse skin was more responsive than WT or TG2KO mouse skin to the action of the pro-inflammatory drug imiquimod.

Necroptosis in the Pathophysiology of Disease

Over the past 15 years, elegant studies have demonstrated that in certain conditions, programed cell death resembles necrosis and depends on a unique molecular pathway with no overlap with apoptosis. This form of regulated necrosis is represented by necroptosis, in which the receptor-interacting protein kinase-3 and its substrate mixed-lineage kinase domain-like protein play a crucial role. With the development of knockout mouse models and molecular inhibitors unique to necroptotic proteins, this cell death has been found to occur in virtually all tissues and diseases evaluated. There are different immunologic consequences depending on whether cells die through apoptosis or necroptosis. Therefore, distinguishing between these two forms of cell death may be crucial during pathologic evaluations. In this review, we provide an understanding of necroptotic cell-death and highlight diseases in which necroptosis has been found to play a role. We also discuss the inhibitors of necroptosis and the ways these inhibitors have been used in preclinical models of diseases. These two discussions offer an understanding of the role of necroptosis in diseases and will foster efforts to pharmacologically target this unique yet pervasive form of programed cell death in the clinic.

Targeting the cutaneous lymphocyte antigen (CLA) in inflammatory and neoplastic skin conditions

Introduction: The cutaneous lymphocyte antigen interacts with E-selectin on endothelial cells and is expressed on 15% of circulating T-cells. Skin-homing T-cells express the cutaneous lymphocyte antigen and play a role in local cutaneous immunity in inflammatory reactions and neoplastic conditions.Areas covered: Lymphocyte extravasation is the essential para-physiological mechanism enabling immune surveillance of tissues for tumors as well as effector cell recruitment to inflammatory sites.The authors focused on skin inflammatory disorders, on cutaneous lymphoproliferative disease, and on other skin malignancies.Expert opinion: Interfering with leukocyte extravasation has been regarded as an attractive strategy in skin disorders, in the past for inflammatory conditions and more recently for cutaneous T-cell lymphomas. Therapeutic blocking of skin-homing interactions has been attempted in psoriasis and atopic dermatitis and has been achieved in the treatment of cutaneous T-cell lymphomas. Cutaneous lymphocyte antigen is a potential molecular target for both systemic and skin-directed therapy for cutaneous T-cell lymphomas.

Pathophysiology of Atopic Dermatitis and Psoriasis: Implications for Management in Children

Atopic dermatitis (AD) and psoriasis are chronic inflammatory skin diseases associated with a significant cutaneous and systemic burden of disease as well as a poor health-related quality of life. Here, we review the complex pathophysiology of both AD and psoriasis and discuss the implications for treatment with current state-of-the-art and emerging topical and systemic therapies. Both AD and psoriasis are caused by a complex combination of immune dysregulation, skin-barrier disruption, genetic factors, and environmental influences. Previous treatments for both diseases were limited to anti-inflammatory agents that broadly suppress inflammation. Emerging insights into relevant pathways, including recognition of the role of T-helper type 2 driven inflammation in AD and T-helper 1 and 17 driven inflammation in psoriasis, have led to a therapeutic revolution. There are a number of novel treatment options available for AD and psoriasis with many more currently under investigation.

Fisetin, a 3,7,3',4'-Tetrahydroxyflavone Inhibits the PI3K/Akt/mTOR and MAPK Pathways and Ameliorates Psoriasis Pathology in 2D and 3D Organotypic Human Inflammatory Skin Models

Psoriasis is a chronic immune-mediated skin disease that involves the interaction of immune and skin cells, and is characterized by cytokine-driven epidermal hyperplasia, deviant differentiation, inflammation, and angiogenesis. Because the available treatments for psoriasis have significant limitations, dietary products are potential natural sources of therapeutic molecules, which can repair the molecular defects associated with psoriasis and could possibly be developed for its management. Fisetin (3,7,3',4'-tetrahydroxyflavone), a phytochemical naturally found in pigmented fruits and vegetables, has demonstrated proapoptotic and antioxidant effects in several malignancies. This study utilized biochemical, cellular, pharmacological, and tissue engineering tools to characterize the effects of fisetin on normal human epidermal keratinocytes (NHEKs), peripheral blood mononuclear cells (PBMC), and CD4+ T lymphocytes in 2D and 3D psoriasis-like disease models. Fisetin treatment of NHEKs dose- and time-dependently induced differentiation and inhibited interleukin-22-induced proliferation, as well as activation of the PI3K/Akt/mTOR pathway. Fisetin treatment of TNF-α stimulated NHEKs also significantly inhibited the activation of p38 and JNK, but had enhanced effect on ERK1/2 (MAPK). In addition, fisetin treatment significantly decreased the secretion of Th1/Th-17 pro-inflammatory cytokines, particularly IFN-γ and IL-17A by 12-O-tetradecanolylphorbol 13-acetate (TPA)-stimulated NHEKs and anti-CD3/CD28-activated human PBMCs. Furthermore, we established the in vivo relevance of fisetin functions, using a 3D full-thickness human skin model of psoriasis (FTRHSP) that closely mimics in vivo human psoriatic skin lesions. Herein, fisetin significantly ameliorated psoriasis-like disease features, and decreased the production of IL-17 by CD4+ T lymphocytes co-cultured with FTRHSP. Collectively, our data identify the prodifferentiative, antiproliferative, and anti-inflammatory effects of fisetin, via modulation of the PI3K-Akt-mTOR and p38/JNK pathways and the production of cytokines in 2D and 3D human skin models of psoriasis. These results suggest that fisetin has a great potential to be developed as an effective and inexpensive agent for the treatment of psoriasis and other related inflammatory skin disorders.

Anti-Inflammatory Effects of Phenolic Compounds Isolated from Quercus Mongolica Fisch. ex Ledeb. on UVB-Irradiated Human Skin Cells

Quercus mongolica Fisch. ex Ledeb. (QM) has been used as an oriental traditional medicine to relieve hemorrhoids, fever, and enteritis. We screened the inhibitory activities of the extracts and compounds (1–6) isolated from QM on the production of inflammatory cytokines and chemokines to evaluate their anti-inflammatory activities. Further, we evaluated the expression levels of cytokines, chemokines, and immune factors on pedunculagin (PC, 1), which was selected from isolated compounds (1–6) because of its potential anti-inflammation effect. Additionally, we evaluated whether the inflammation mitigation effects of PC (1) following UVB exposure in keratinocytes occurred because of nuclear factor (NF)-κB and signal transducer and activator of transcription (STAT)/Janus kinase (JAK) activation. PC (1) remarkably suppressed interleukin (IL)-6, IL-10, IL-13, and monocyte chemoattractant protein-1 (MCP-1) mRNA expression and reduced the mRNA expression level of Cyclooxygenase-2 (COX-2) and also reduced the phosphorylation of p38 mitogen-activated protein kinases (p38), c-Jun N-terminal kinase (JNK), and extracellular signal-regulated kinase (ERK) in a concentration-dependent manner.

DNA methylation age is not affected in psoriatic skin tissue

Background

Psoriasis (Ps) is a common chronic inflammatory skin disease. The keratinocytes of psoriatic skin defy normal apoptosis and exhibit active cell proliferation. Aberrant DNA methylation (DNAm) has been suggested relevant through regulating the expression of Ps susceptibility genes. However, it is unclear whether the biological age inferred from DNA methylome is affected.

Results

To address the above issue, we applied a recently developed methylation clock model to our Chinese Han population dataset, which includes DNAm data of 114 involved psoriatic skin tissues (PP) and 41 uninvolved psoriatic skin tissues (PN) from Ps patients, and 62 normal skin tissues (NN) from health controls. We first confirmed the applicability of the clock in PN and NN. We then showed that PP samples have largely unchanged DNAm age, and that no association was observed between available clinical features and DNAm age acceleration. Examination of genome-wide CpGs yielded age-associated CpGs with concordant age-association coefficients among the three groups, which was also supported by an external dataset. We also interestingly observed two clock CpGs differentially methylated between PP and PN.

Conclusions

Overall, our results suggest no significant alteration in DNAm age in PN and PP. Therefore, the increase in keratinocyte proliferation and alteration in DNAm caused by Ps may not affect the biological age of psoriatic skin tissue.

Electronic supplementary material

The online version of this article (10.1186/s13148-018-0584-y) contains supplementary material, which is available to authorized users.

Hodgkin's lymphoma in a patient on adalimumab treatment for psoriasis

Adalimumab is a human monoclonal antibody which targets tumor necrosis factor (TNF)-alpha. It is produced by recombinant DNA technology, using a mammalian cell expression system and is widely-known to treat a number of immune-mediated conditions, including psoriasis. There has been a growing concern regarding the possible association between TNF-alpha inhibitors and malignancy. In this case report, we describe the case of a 20-year-old woman, known to have been suffering from chronic plaque psoriasis for 12 years, and who developed Hodgkin's lymphoma within five weeks of beginning adalimumab treatment.

The role of PI3K/AKT/FOXO signaling in psoriasis

Phosphatidylinositol 3-kinase (PI3K) and protein kinase B (AKT) signaling pathway play a central role in multiple cellular functions such as cell proliferation and survival. The forkhead box O (FOXO) transcription factors are negatively regulated by the PI3K/AKT signaling pathway and considered to have inhibitory effect on cell proliferation. Psoriasis is a multifactorial disease with a strong genetic background and characterized by hyperproliferative keratinocyte. PI3K signaling regulates proliferation of keratinocyte by activating AKT and other targets, and by inducing FOXO downregulation. The amplification of PI3K and AKT and the loss of the FOXO are gradually being recognized in psoriatic lesions. The upstream and downstream of PI3K/AKT signaling molecules such as tumor suppressor phosphatase and tensin homolog (PTEN) and mammalian target of Rapamycin (mTOR), respectively, are also frequently altered in psoriasis. In this review, we highlight the recent studies on the roles and mechanisms of PI3K and AKT in regulating hyperproliferation of keratinocyte, and the roles of the downstream targets FOXO in psoriasis. Finally, we summarized that PI3K/AKT/FOXO signaling and its upstream and downstream molecule which could be underlying therapeutic target for psoriasis. This article is part of a special issue entitled: PI3K-AKT-FOXO axis in psoriasis.

Potentiation of Psoriasis-Like Inflammation by PCSK9

Psoriasis is a systemic inflammatory disease, associated with metabolic disorders, including high level of low-density lipoprotein. PCSK9, which promotes the degradation of low-density lipoprotein receptors and, therefore, the increased concentration of circulating low-density lipoprotein, is also involved in inflammation. This study aims to examine the role of PCSK9 in psoriasis and to investigate the potential of topically applying small interfering RNA targeting Pcsk9 as a psoriasis treatment. We investigated the expression of PCSK9 in lesions of psoriasis patients and imiquimod-induced psoriatic reactions in Pcsk9-knockout and Pcsk9 small interfering RNA-treated mice, and we also used cultured human keratinocytes to investigate the role of PCSK9 in regulating cell proliferation and apoptosis. We found that PCSK9 is overexpressed in psoriatic lesions and that suppressing Pcsk9 can decrease the inflammatory reaction induced by imiquimod treatment and inhibit hyperproliferation of keratinocytes. We also found that suppressing PCSK9 can significantly alter the cell cycle and induce apoptosis of human keratinocytes. Taken together, our findings indicate that PCSK9 plays an important role in psoriasis and may be a therapeutic target.

Phosphatidylglycerol Inhibits Toll-Like Receptor-Mediated Inflammation by Danger-Associated Molecular Patterns

Psoriasis is a common skin disorder characterized by hyperproliferation and aberrant differentiation of epidermal keratinocytes and inflammation. We previously showed that phosphatidylglycerol (PG) can regulate keratinocyte function and suppress skin inflammation. Based on data suggesting that PG can inhibit toll-like receptor (TLR) activation induced by microorganisms and their components, we determined whether PG can inhibit TLR activation in response to antimicrobial peptides. These peptides, which are up-regulated in psoriasis, are known to function as danger-associated molecular patterns (i.e., DAMPs) to activate TLRs and the innate immune system. Because S100A9 is elevated in psoriatic skin and in animal models of psoriasis, we selected S100A9 as a representative antimicrobial peptide DAMP. We showed that in primary keratinocytes and a macrophage cell line, PG suppressed inflammatory mediator production induced by recombinant S100A9 functioning through both TLR2 and TLR4. In addition, PG, but not phosphatidylcholine, inhibited downstream S100A9-elicited TLR2 and NF-κB activation. These results, to our knowledge previously unreported, show PG's ability to inhibit DAMP-induced TLR activation, thereby reducing inflammatory signals. In addition, topical PG ameliorated skin lesions and inflammation in a mouse model of psoriasis. Together, these results suggest the possibility of developing PG as a therapy for psoriasis.

Anti-Inflammatory and Skin-Moisturizing Effects of a Flavonoid Glycoside Extracted from the Aquatic Plant Nymphoides indica in Human Keratinocytes

Nymphoides indica, an aquatic plant, is used as folk medicine in some countries. Our previous study demonstrated that the methanol extract of N. indica inhibited the activity of tyrosinases, tyrosine related protein (TRP)1 and TRP2, and microphthalmia-associated transcription factor, as well as the activity of protein kinase A, by effectively inhibiting cyclic adenosine monophosphate. Although the biological activities of N. indica extract have been reported, there are no reports on the skin bioactivity of the main compound(s) on human keratinocytes. This study investigated the anti-inflammatory and moisturizing effects of quercetin 3,7-dimethyl ether 4′-glucoside (QDG) isolated from N. indica. In brief, ultraviolet B irradiated keratinocytes were pretreated with different concentrations of QDG, and the effects of QDG on various inflammatory markers were determined. QDG significantly inhibited inflammation-related cytokines and chemokines and enhanced the activation of skin barrier factors. Additionally, QDG also attenuated phosphorylation inhibition of the upstream cytokines and nuclear factor-κB expression. These results suggest that QDG isolated from N. indica may serve as a potential source of bioactive substances for chronic inflammatory skin diseases.

RETRACTED: NFKB1 mediates Th1/Th17 activation in the pathogenesis of psoriasis

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor and the authors, following concerns raised in the public domain. The authors informed the journal that they had found that the psoriasis model panel and the vector panel of Fig 4D were duplicated. The authors think that the relevant results are not sufficient to support the conclusions drawn from this study.

RNA-seq and flow-cytometry of conventional, scalp, and palmoplantar psoriasis reveal shared and distinct molecular pathways

It has long been recognized that anatomic location is an important feature for defining distinct subtypes of plaque psoriasis. However, little is known about the molecular differences between scalp, palmoplantar, and conventional plaque psoriasis. To investigate the molecular heterogeneity of these psoriasis subtypes, we performed RNA-seq and flow cytometry on skin samples from individuals with scalp, palmoplantar, and conventional plaque psoriasis, along with samples from healthy control patients. We performed differential expression analysis and network analysis using weighted gene coexpression network analysis (WGCNA). Our analysis revealed a core set of 763 differentially expressed genes common to all sub-types of psoriasis. In contrast, we identified 605, 632, and 262 genes uniquely differentially expressed in conventional, scalp, and palmoplantar psoriasis, respectively. WGCNA and pathway analysis revealed biological processes for the core genes as well as subtype-specific genes. Flow cytometry analysis revealed a shared increase in the percentage of CD4+ T regulatory cells in all psoriasis subtypes relative to controls, whereas distinct psoriasis subtypes displayed differences in IL-17A, IFN-gamma, and IL-22 production. This work reveals the molecular heterogeneity of plaque psoriasis and identifies subtype-specific signaling pathways that will aid in the development of therapy that is appropriate for each subtype of plaque psoriasis.

Phosphorylation of intracellular signalling molecules in peripheral blood cells from patients with psoriasis on originator or biosimilar infliximab

BACKGROUND

Psoriasis vulgaris is a chronic, inflammatory skin disease characterized by a dysregulated immune response and it is associated with substantial systemic comorbidities. Biological drugs such as tumour necrosis factor (TNF)-α inhibitors can ameliorate the disease but are expensive. Biosimilar drugs have the same amino-acid sequence as the originator, but differences in manufacturing can affect biological activity, efficacy and tolerability.

OBJECTIVES

To explore potential differences in intracellular phosphorylation of signalling molecules in peripheral blood cells from patients with psoriasis treated with the TNF-α inhibitor infliximab compared with healthy controls, and to investigate if the phosphorylation pattern was influenced by switching from the originator infliximab to the biosimilar CT-P13.

METHODS

By flow cytometry, we measured phosphorylation of nuclear factor kappa B, extracellular signal-regulated kinase 1/2, p38 mitogen-activated protein kinase and signal transducer and activator of transcription 3, before and after TNF-α stimulation in monocytes and T, B, natural killer and CD3⁺  CD56⁺ cells from 25 patients with psoriasis treated with infliximab and 19 healthy controls.

RESULTS

At inclusion, phosphorylation levels of peripheral blood mononuclear cells (PBMCs) were increased in patients with psoriasis compared with healthy controls, even though clinical remission had already been achieved. Phosphorylation levels declined in patients on both originator infliximab and biosimilar during continued treatment. No significant differences were detected between the two medications after 12 months.

CONCLUSIONS

Patients with psoriasis on infliximab have higher activation levels of PBMCs than do healthy controls, possibly reflecting systemic inflammation. Switching from the originator infliximab to biosimilar CT-P13 did not affect phosphorylation levels or clinical parameters, suggesting that CT-P13 is a noninferior treatment alternative to the originator infliximab.

RIPK1 downregulation in keratinocyte enhances TRAIL signaling in psoriasis

BACKGROUND

Psoriasis, a common inflammatory skin disorder characterized by scaly erythema and plaques, is induced by dysregulation of dendritic cell- and T cell-mediated immune reaction. Receptor-interacting protein kinase 1 (RIPK1) regulates inflammatory signaling in response to stimuli such as TNF-α, TRAIL, and TLRs, resulting in apoptosis, necroptosis and NF-κB activation. However, the physiological relevance in human epidermis remains elusive.

OBJECTIVE

In this study, we examined whether RIPK1 is involved in the pathogenesis of psoriasis vulgaris.

METHODS

Skin samples of eight patients with psoriasis vulgaris were investigated by western blotting and immunohistochemistry. The functions of RIPK1 in keratinocytes were examined by RT-PCR and ELISA in vitro. TRAIL-neutralization-experiment was employed in an imiquimod-induced murine psoriasis model.

RESULTS

In lesional psoriatic epidermis, RIPK1-expression was decreased compared with that in normal epidermis. Cytokines involved in the pathomechanism of psoriasis, such as IL-1β, IL-17A, IL-22 and TRAIL, reduced RIPK1-expression in normal human epidermal keratinocytes (HEK) in vitro. In addition, RIPK1-knockdown enhanced TRAIL-mediated expression of psoriasis-relating cytokines, such as IL-1β, IL-6, IL-8, TNF-α, in HEK. Numerous TRAIL-positive cells were detected in the dermis of lesional psoriatic skin, and TRAIL receptors were expressed in psoriatic epidermis and HEK in conventional cultures. Moreover, TRAIL-neutralization in an imiquimod-induced murine psoriasis model remarkably improved skin phenotypes, such as ear thickness, and TNF-α expression in lesional skin.

CONCLUSIONS

These results lead us to conclude that RIPK1-downregulation in keratinocytes increases their susceptibility to TRAIL stimulation, and plays a role in the pathogenesis of psoriasis vulgaris.

Psoriasiform skin disease in transgenic pigs with high-copy ectopic expression of human integrins α2 and β1

Psoriasis is a complex human-specific disease characterized by perturbed keratinocyte proliferation and a pro-inflammatory environment in the skin. Porcine skin architecture and immunity are very similar to that in humans, rendering the pig a suitable animal model for studying the biology and treatment of psoriasis. Expression of integrins, which is normally confined to the basal layer of the epidermis, is maintained in suprabasal keratinocytes in psoriatic skin, modulating proliferation and differentiation as well as leukocyte infiltration. Here, we generated minipigs co-expressing integrins α2 and β1 in suprabasal epidermal layers. Integrin-transgenic minipigs born into the project displayed skin phenotypes that correlated with the number of inserted transgenes. Molecular analyses were in good concordance with histological observations of psoriatic hallmarks, including hypogranulosis and T-lymphocyte infiltration. These findings mark the first creation of minipigs with a psoriasiform phenotype resembling human psoriasis and demonstrate that integrin signaling plays a key role in psoriasis pathology.

Summary: A cloned porcine disease model to advance topical treatment in the debilitating skin disorder psoriasis.

Anti-IL-12/IL-23p40 antibody ameliorates dermatitis and skin barrier dysfunction in mice with imiquimod-induced psoriasis-like dermatitis

Psoriasis is a chronic inflammatory skin disease characterized by erythema, skin hyperplasia, scales, and keratinocyte hyperproliferation. While the cause of psoriasis is not clearly understood, a dysregulated immune system, especially activation of IL-23/IL-17 axis, has been strongly implicated in the pathogenesis of psoriasis. For example, anti-IL-23 therapy is effective in psoriasis patients, and thus IL-23 is considered as a potential therapeutic target for the treatment of psoriasis. The skin barrier provides protection of the human body against infection from external pathogens. Dysfunction of the skin barrier is also one of the characteristics in psoriasis and is correlated with disease severity. However, there have been no reports regarding the effectiveness of antipsoriatic agents on the skin barrier dysfunction of psoriasis. In this study, we examined the effect of anti-IL-12/IL-23p40 monoclonal antibody (p40 mAb) on dermatitis symptoms and skin barrier dysfunction in mice with imiquimod-induced psoriasis-like dermatitis. We found that p40 mAb suppressed epidermal thickness and increased transepidermal water loss (TEWL) as indicator for skin barrier function with accompanying suppression of IL-23p19, IL-17A, IL-22, and keratin 16 gene expression. These results suggest that p40 mAb is not only effective against dermatitis symptoms but also skin barrier dysfunction in mice with imiquimod-induced psoriasis-like dermatitis. This is the first report on the effect of p40 mAb on skin barrier dysfunction related to psoriasis. Taken together, our results indicate the possibility of new insights as well as the therapeutic potential of anti-IL-23 for the treatment of psoriasis.

High fat diet exacerbates murine psoriatic dermatitis by increasing the number of IL-17-producing γδ T cells

Psoriasis is a common, chronic inflammatory skin disease characterized by epidermal hyperplasia via the IL-23/IL-17 axis. Various studies have indicated the association between obesity and psoriasis, however, the underlying mechanisms remains unclarified. To this end, we focused on high-fat diet (HFD) in this study, because HFD is suggested as a contributor to obesity, and HFD-fed mice exhibit exacerbated psoriatic dermatitis. Using murine imiquimod (IMQ)-induced psoriasis and HFD-induced obesity models, we have revealed a novel mechanism of HFD-induced exacerbation of psoriatic dermatitis. HFD-fed mice exhibited aggravated psoriatic dermatitis, which was accompanied with increased accumulation of IL-17A-producing Vγ4⁺ γδ T cells in the skin. HFD also induced the increase of Vγ4⁺ γδ T cells in other organs such as skin draining lymph nodes, which preceded the increase of them in the skin. In addition, HFD-fed mice displayed increased expression of several γδ T cell-recruiting chemokines in the skin. On the other hand, ob/ob mice, another model of murine obesity on normal diet, did not exhibit aggravated psoriatic dermatitis nor accumulation of γδ T cells in the dermis. These results indicate that HFD is a key element in exacerbation of IMQ-induced psoriatic dermatitis, and further raise the possibility of HFD as a factor that links obesity and psoriasis.

Expression of Th1 and Th2 Cytokine and Associated Transcription Factors in Peripheral Blood Mononuclear Cells and Correlation with Disease Severity

BACKGROUND

Psoriasis is a T cell-mediated autoimmune disease in patients with elevated levels of proinflammatory cytokines belonging mainly to the Th1 pathway. We investigated whether treatment of psoriasis patients with methotrexate (MTX), along with micronutrients, modulated mRNA expression of Th1 and Th2 components and whether expression of these components correlated with psoriasis severity.

METHODS

Thirty plaque-type psoriasis patients with Psoriasis Area and Severity Index (PASI) scores greater than 10 were recruited; these were 15 non-micronutrients taking- (NMT) patients treated with MTX daily (0.2-0.3 mg/kg/week), and 15 micronutrients taking- (MT) patients treated with MTX plus a micronutrient supplement daily, for 12 weeks. Blood samples were collected immediately before treatment (baseline) and after 12 weeks of treatment. Taqman quantitative real-time polymerase chain reaction (qPCR) was applied to analyze the expression of the Th1 components T-bet, interleukin-12 (IL-12), and interferon-gamma (IFN-Υ), and the Th2 components GATA-3 and interleukin-4 (IL-4). Disease severity was measured using the PASI scoring system.

RESULTS

Significant clinical improvement in the MT group coincided with significant down-regulation of Th1 and up-regulation of Th2 markers (P<0.05). With respect to the PASI-75, (defined as a 75% or greater reduction in the PASI score) cut-off point, expression of IFN-γ in the MT group with PASI scores above 75 was significantly less than that of patients in the NMT group (P=0.05). Also, GATA3 and IL-4 mRNA expression in the MT group with PASI scores greater than above 75 was significantly greater than that of patients in the NMT group (P=0.05 and 0.04, respectively).

CONCLUSION

Based on significant attenuation of the PASI score, which correlated with upregulation of Th2 pathway markers in the MT group, we recommend administration of micronutrients combined with MTX for psoriasis patients. Our results contribute to a better understanding of methotrexate immunepathogenesis mechanisms and their correlations to clinical responses in psoriasis.

Immune responses and parasitological observations induced during probiotic treatment with medicinal Trichuris suis ova in a healthy volunteer

Ingestion of eggs (ova) of the porcine nematode parasite Trichuris suis (TSO) may reduce the severity of autoimmune disorders, however the development of TSO treatment as a useful therapy for autoimmune diseases is hampered by a lack of knowledge on the development of the parasite and the nature of the local immune responses in humans. Here, we used colonoscopy to investigate the development of T. suis and related mucosal and systemic immune responses during TSO treatment in an intestinally healthy male volunteer. TSO treatment induced T. suis-specific serum antibodies, a transient blood eosinophilia, and increases in IFNγ⁺ and IL4⁺ cells within the circulating CD4⁺ T-cell population. Increased expression of genes encoding cytokines (IL4, IL10, IL17 and TGF-β), and transcription factors (FOXP3, GATA3 and RORC) were apparent in the ascending and transverse colon (the predilection site of the worms), whereas only limited changes in gene expression were observed proximally (ileum) and distally (descending colon) to the infected tissue. We further show that T. suis is able to colonise the human colon, with a number of worms developing to a similar size and morphology observed in the natural pig host, and a small number of unembryonated eggs were passed in the faeces, indicating patent infection. Notably, the volunteer experienced a substantial improvement in psoriasis during the course of TSO treatment. Thus, TSO treatment induced a mixed Th1/Th2/T regulatory response at the local site of infection, which was also reflected to some extent in the peripheral circulation. These results, together with the first definitive observations that T. suis can mature to adult size and reproduce in humans, shed new light on the interaction between the human immune system and probiotic helminth treatment, which should facilitate further development of this novel therapeutic option.

Correlation analysis of the HLA-DPB1*05:01 and BTNL2 genes within the histocompatibility complex region with a clinical phenotype of psoriasis vulgaris in the Chinese Han population

BACKGROUND

The human major histocompatibility complex (MHC) is known to be highly polymorphic and has been identified to be associated with numerous diseases. The HLA-DPB1 and BTNL2 genes were associated with psoriasis for the first time. The present study aims to investigate the relevance of the HLA-DPB1 and BTNL2 genes with respect to clinical phenotypes of psoriasis vulgaris (PV).

METHODS

To investigate whether the HLA-DPB1 and BTNL2 polymorphisms were associated with clinical phenotypes of PV in Chinese Han population, we conducted an analysis in case-controls and case-only subjects (9906 controls and 8744 cases) via MHC targeted sequencing stratified analysis.

RESULTS

In cases and controls, analysis showed that the genotype of HLA-DPB1*05:01 was associated with type of guttate [p = 3.914 × 10^-2 , odds ratio (OR = 0.9335)] and northern region (p = 1.182 × 10^-3 , OR = 0.9108). In the case-only analysis, the genotype of HLA-DPB1*05:01 was significantly correlated with geographical region (p = 1.36 × 10^-3 , OR = 1.134). In cases and controls, analysis showed that the genotype of BTNL2 (rs 41355746) was associated with being male (p = 2.563 × 10^-2 , OR = 0.8897), early-onset (p = 9.399 × 10^-3 , OR = 0.8856), guttate (p = 2.469 × 10^-2 , OR = 0.8558) and family history (p = 1.51 × 10^-4 , OR = 0.772). In the case-only analysis, the genotype of BTNL2 (rs41355746) was significantly correlated with family history (p = 1.768 × 10^-3 , OR = 0.757) and age of onset (p = 3.818 × 10^-2 , OR = 1.195).

CONCLUSIONS

The results of the present study indicate that the HLA-DPB1*05:01 gene was associated with the geographical region of PV and the BTNL2 gene was significantly associated with family history and age of onset of PV. In conclusion, the HLA-DPB1*05:01 and BTNL2 genes might be responsible for the complicacy of clinical features.