Interplay between keratinocytes and immune cells—Recent insights into psoriasis pathogenesis

Electroacupuncture and methotrexate cooperate to ameliorate psoriasiform skin inflammation by regulating the immune balance of Th17/Treg

Psoriasis is an autoinflammatory dermatosis, while methotrexate (MTX) is an immunosuppressant used to treat psoriasis. However, conventional immunosuppressants may cause various side effects. Acupuncture has potential benefits in treating psoriasis based on its anti-inflammatory effects. However, the immune mechanisms underlying its effects remain unclear. In this study, imiquimod-induced psoriatic mice were used to investigate the effects and mechanisms of electroacupuncture (EA) and, in particular, its joint treatment with MTX. We found that treatment with either EA or MTX ameliorated psoriasiform skin lesions, improved skin pathology and reduced proinflammatory cytokines in the skin, while joint treatment with both EA and MTX further alleviated the skin lesions and inflammation compared to either one alone. Moreover, percentages of CD4+ IL-17A+ Th17 cells in the skin and lymph nodes were decreased by EA or MTX and further lowered by combined EA+MTX treatment. Similarly, EA or MTX also reduced their RORγt expression. On the contrary, CD4+ FoxP3+ Treg frequency in psoriatic mice was augmented by EA or MTX and further increased by the joint treatment. However, depleting Tregs mostly reversed the therapeutic effects of EA or EA plus MTX. Additionally, the phosphorylated NF-κB (p65) expression was suppressed by treatment with EA, MTX or better with EA+MTX. Meanwhile, the anti-inflammatory effects of EA plus MTX were offset by an NF-κB agonist. Thus, this study has revealed that EA cooperates with MTX to balance Th17/Treg responses and to ameliorate psoriasiform skin inflammation through suppressing NF-κB activation. Our findings may be implicated for treating human psoriasis.

Sensory ASIC3 channel exacerbates psoriatic inflammation via a neurogenic pathway in female mice

Psoriasis is an immune-mediated skin disease associated with neurogenic inflammation, but the underlying molecular mechanism remains unclear. We demonstrate here that acid-sensing ion channel 3 (ASIC3) exacerbates psoriatic inflammation through a sensory neurogenic pathway. Global or nociceptor-specific Asic3 knockout (KO) in female mice alleviates imiquimod-induced psoriatic acanthosis and type 17 inflammation to the same extent as nociceptor ablation. However, ASIC3 is dispensable for IL-23-induced psoriatic inflammation that bypasses the need for nociceptors. Mechanistically, ASIC3 activation induces the activity-dependent release of calcitonin gene-related peptide (CGRP) from sensory neurons to promote neurogenic inflammation. Botulinum neurotoxin A and CGRP antagonists prevent sensory neuron-mediated exacerbation of psoriatic inflammation to similar extents as Asic3 KO. In contrast, replenishing CGRP in the skin of Asic3 KO mice restores the inflammatory response. These findings establish sensory ASIC3 as a critical constituent in psoriatic inflammation, and a promising target for neurogenic inflammation management.

Advance in Multi-omics Research Strategies on Cholesterol Metabolism in Psoriasis

The skin is a complex and dynamic organ where homeostasis is maintained through the intricate interplay between the immune system and metabolism, particularly cholesterol metabolism. Various factors such as cytokines, inflammatory mediators, cholesterol metabolites, and metabolic enzymes play crucial roles in facilitating these interactions. Dysregulation of this delicate balance contributes to the pathogenic pathways of inflammatory skin conditions, notably psoriasis. In this article, we provide an overview of omics biomarkers associated with psoriasis in relation to cholesterol metabolism. We explore multi-omics approaches that reveal the communication between immunometabolism and psoriatic inflammation. Additionally, we summarize the use of multi-omics strategies to uncover the complexities of multifactorial and heterogeneous inflammatory diseases. Finally, we highlight potential future perspectives related to targeted drug therapies and research areas that can advance precise medicine. This review aims to serve as a valuable resource for those investigating the role of cholesterol metabolism in psoriasis.

Targeted siRNA Therapy for Psoriasis: Translating Preclinical Potential into Clinical Treatments

Psoriasis is a chronic inflammatory skin disease characterized by the excessive proliferation of keratinocytes and heightened immune activation. Targeting pathogenic genes through small interfering RNA (siRNA) therapy represents a promising strategy for the treatment of psoriasis. This mini-review provides a comprehensive summary of siRNA research targeting the pathogenesis of psoriasis, covering aspects such as keratinocyte function, inflammatory cell roles, preclinical animal studies, and siRNA delivery mechanisms. It details recent advancements in RNA interference that modulate key factors including keratinocyte proliferation (Fibroblast Growth Factor Receptor 2, FGFR2), apoptosis (Interferon Alpha Inducible Protein 6, G1P3), differentiation (Grainyhead Like Transcription Factor 2, GRHL2), and angiogenesis (Vascular Endothelial Growth Factor, VEGF); immune cell infiltration and inflammation (Tumor Necrosis Factor-Alpha, TNF-α; Interleukin-17, IL-17); and signaling pathways (JAK-STAT, Nuclear Factor Kappa B, NF-κB) that govern immunopathology. Despite significant advances in siRNA-targeted treatments for psoriasis, several challenges persist. Continued scientific developments promise the creation of more effective and safer siRNA medications, potentially enhancing the quality of life for psoriasis patients and revolutionizing treatments for other diseases. This article focuses on the most recent research advancements in targeting the pathogenesis of psoriasis with siRNA and explores its future therapeutic prospects.

A quantitative systems pharmacology model for certolizumab pegol treatment in moderate-to-severe psoriasis

Background

Psoriasis is a chronic immune-mediated inflammatory systemic disease with skin manifestations characterized by erythematous, scaly, itchy and/or painful plaques resulting from hyperproliferation of keratinocytes. Certolizumab pegol [CZP], a PEGylated antigen binding fragment of a humanized monoclonal antibody against TNF-alpha, is approved for the treatment of moderate-to-severe plaque psoriasis. Patients with psoriasis present clinical and molecular variability, affecting response to treatment. Herein, we utilized an in silico approach to model the effects of CZP in a virtual population (vPop) with moderate-to-severe psoriasis. Our proof-of-concept study aims to assess the performance of our model in generating a vPop and defining CZP response variability based on patient profiles.

Methods

We built a quantitative systems pharmacology (QSP) model of a clinical trial-like vPop with moderate-to-severe psoriasis treated with two dosing schemes of CZP (200 mg and 400 mg, both every two weeks for 16 weeks, starting with a loading dose of CZP 400 mg at weeks 0, 2, and 4). We applied different modelling approaches: (i) an algorithm to generate vPop according to reference population values and comorbidity frequencies in real-world populations; (ii) physiologically based pharmacokinetic (PBPK) models of CZP dosing schemes in each virtual patient; and (iii) systems biology-based models of the mechanism of action (MoA) of the drug.

Results

The combination of our different modelling approaches yielded a vPop distribution and a PBPK model that aligned with existing literature. Our systems biology and QSP models reproduced known biological and clinical activity, presenting outcomes correlating with clinical efficacy measures. We identified distinct clusters of virtual patients based on their psoriasis-related protein predicted activity when treated with CZP, which could help unravel differences in drug efficacy in diverse subpopulations. Moreover, our models revealed clusters of MoA solutions irrespective of the dosing regimen employed.

Conclusion

Our study provided patient specific QSP models that reproduced clinical and molecular efficacy features, supporting the use of computational methods as modelling strategy to explore drug response variability. This might shed light on the differences in drug efficacy in diverse subpopulations, especially useful in complex diseases such as psoriasis, through the generation of mechanistically based hypotheses.

Zerumbone attenuates the excessive proliferation of keratinocytes in psoriasis mice through regulating NLRP3/NF-κB pathway

Psoriasis is a common chronic disease, and existing treatment regimens often exhibit certain toxicities and side effects. Zerumbone (Zer) may possess therapeutic effect, and the objective of this study is to investigate the effect of Zer on psoriasis. A mouse model of psoriasis was established using imiquimod cream, and the role of Zer on the pathological alterations in psoriatic mouse skin was evaluated by psoriasis area and severity index (PASI) score; the effect of Zer on keratinocyte proliferation was evaluated via hematoxylin and eosin staining, Zen image analysis, and immunofluorescence; Immunohistochemistry and enzyme-linked immunoassay were used to evaluate the effect of Zer on tissue inflammatory responses, while malondialdehyde (MDA) and glutathione (GSH) levels were measured to elucidate the role of Zer in modulating oxidative stress; the signaling pathway regulated by Zer was evaluated by western blotting. The results demonstrated that Zer could alleviate the pathological manifestations of psoriasis, reduce PASI score, reduce skin pathological damage and epidermal hyperplasia, diminish the number of CD8+ T cells and cytokine expression levels, decrease the level of MDA and GSH and increase the expression of Nrf and HO-1. Zer was found to regulate the NLRP3/nuclear factor-kappa B (NF-κB) signaling pathway. In conclusion, Zer ameliorated the symptoms of psoriasis in mice, suppressed the keratinocyte hyperproliferation, and mitigates inflammation and oxidative stress in psoriatic skin tissue by regulating the NLRP3/NF-κB pathway.

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.

Etanercept ameliorates psoriasis progression through regulating high mobility group box 1 pathway

BACKGROUND

As a common skin disease, psoriasis is related to inflammation and immune response. Due to the frequent recurrence of psoriasis, the treatment of psoriasis remains a clinical challenge. As an effective tumor necrosis factor-alpha (TNF-α) inhibitor, etanercept has been used for the treatment of psoriasis. However, some patients with psoriasis have no response to etanercept or discontinue treatment. To improve the therapeutic effect of etanercept, searching the potential biomarkers and investigating the related mechanisms of etanercept in the treatment of psoriasis are vital.

MATERIALS AND METHODS

We stimulated HaCaT cells with lipopolysaccharide (LPS) to generate cellular psoriatic changes and established an imiquimod (IMQ)-induced psoriasis-like mouse model, and then used an etanercept to treat cell and mouse model.

RESULTS

Etanercept alleviated IMQ-induced pathological changes and inflammation, and it also decreased the protein expression of high mobility group box 1 (HMGB1), receptor for advanced glycation end-products, and toll-like receptor 4. Moreover, the results of in vitro experiments showed that etanercept inhibited proliferation and inflammation, and promoted cell cycle arrest and apoptosis in LPS-treated HaCaT cells. Knockdown of HMGB1 further enhanced the inhibitory effects of etanercept on LPS-treated HaCaT cell viability and inflammation, while overexpression of HMGB1 notably reversed the inhibitory effects of etanercept on LPS-induced HaCaT cell viability and inflammation.

CONCLUSION

Etanercept inhibited proliferation and inflammation and promoted cell cycle arrest and apoptosis in LPS-induced HaCaT cells, and etanercept ameliorated inflammation in a psoriasis-like mouse model.

FXYD3 enhances IL-17A signaling to promote psoriasis by competitively binding TRAF3 in keratinocytes

Psoriasis is a common chronic inflammatory skin disease characterized by inflammatory cell infiltration and epidermal hyperplasia. However, the regulatory complexity of cytokine and cellular networks still needs to be investigated. Here, we show that the expression of FXYD3, a member of the FXYD domain-containing regulators of Na+/K+ ATPases family, is significantly increased in the lesional skin of psoriasis patients and mice with imiquimod (IMQ)-induced psoriasis. IL-17A, a cytokine important for the development of psoriatic lesions, contributes to FXYD3 expression in human primary keratinocytes. FXYD3 deletion in keratinocytes attenuated the psoriasis-like phenotype and inflammation in an IMQ-induced psoriasis model. Importantly, FXYD3 promotes the formation of the IL-17R-ACT1 complex by competing with IL-17R for binding to TRAF3 and then enhances IL-17A signaling in keratinocytes. This promotes the activation of the NF-κB and MAPK signaling pathways and leads to the expression of proinflammatory factors. Our results clarify the mechanism by which FXYD3 serves as a mediator of IL-17A signaling in keratinocytes to form a positive regulatory loop to promote psoriasis exacerbation. Targeting FXYD3 may serve as a potential therapeutic approach in the treatment of psoriasis.

Anti-Psoriatic Effect of Rheum palmatum L. and Its Underlying Molecular Mechanisms

Psoriasis is a chronic, immune-mediated inflammatory skin disorder. Rheum palmatum L. is a common traditional medicinal herb with anti-inflammatory and immunomodulatory activities. This study aimed to investigate the anti-psoriatic effects of the ethanolic extract from R. palmatum L. (RPE) and its chemical constituents, as well as the mechanisms underlying their therapeutic significance. An imiquimod (IMQ)-induced psoriasis-like mouse model was used to examine the anti-psoriatic effect of RPE in vivo. Network pharmacological analysis was performed to investigate the potential targets and related pathways of the RPE components, including rhein, emodin, chrysophanol, aloe-emodin, and physcion. The anti-inflammatory effects and underlying mechanisms of these components were examined using in vitro models. Topical application of RPE alleviated psoriasis-like symptoms and reduced levels of inflammatory cytokines and proliferation markers in the skin. Network pharmacological analysis revealed that RPE components target 20 genes that are linked to psoriasis-related pathways, such as IL-17, MAPK, and TNF signaling pathways. Among the five components of RPE, rhein and emodin showed inhibitory effects on TNF-α and IL-17 production in EL-4 cells, attenuated the production of CXCL8, CXCL10, CCL20, and MMP9, and reduced proliferation in HaCaT cells. Chrysophanol, aloe-emodin, and physcion were less effective than rhein and emodin in suppressing inflammatory responses and keratinocyte proliferation. The effects of these compounds might occur through the inhibition of the ERK, STAT3, and NF-κB signaling pathways. This study suggested the anti-psoriatic effect of RPE, with rhein and emodin as the main contributors that regulate multiple signaling pathways.

Current evidence on the role of lipid lowering drugs in the treatment of psoriasis

Background

Abnormal lipid distribution is observed in patients with psoriasis, which increases their risk for atherosclerosis. Lipid-lowering drugs have a certain curative effect in the treatment of psoriasis, but there is no relevant evidence-based medical evaluation.

Objective

The purpose of this systematic evaluation was to assess the efficacy, safety, and potential mechanisms of action of lipid-lowering drugs for the treatment of psoriasis.

Methods

The PubMed, Embase, Cochrane Central Register of Controlled Trials, Clinical Trial, Chinese National Knowledge Infrastructure (CNKI), China Science and Technology Journal Database, and Wanfang Database were searched for relevant articles from inception to 31 December 2021. The RevMan 5.3 and Cochrane risk-of-bias tool were used for data analysis and risk assessment, respectively. The psoriasis area and severity index (PASI) score is the primary outcome indicator in clinical studies. Based on preclinical studies, we elucidated and mapped the action mechanisms of lipid-lowering drugs in the treatment of psoriasis.

Results

The study included eight randomized controlled studies, four single-arm studies, and four in vitro studies. The results showed that lipid-lowering drugs, particularly statins, administered both orally and topically, can significantly improve psoriatic skin lesions and reduce the PASI scores [standardized mean difference, (SMD): −0.94; 95% CI: [−1.58, −0.31]; p = 0.004]. Oral statins performed best at week eight (SMD: −0.92; 95% CI: [−1.39, −0.44]; p = 0.0001). The mechanism of lipid-lowering drugs in the treatment of psoriasis may be related to the inhibition of keratinocyte proliferation, inhibition of CCL20–CCR6 interaction, and reduction in the levels of inflammatory factors.

Limitations

There are few studies on lipid-lowering drugs and psoriasis, and their small sample sizes may render the evidence unconvincing.

Conclusion

The present findings suggest that lipid-lowering drugs are relieving symptoms in psoriasis. Lipid-lowering drugs, particularly statins, can be used to treat psoriasis with good efficacy and few side effects.

Potential effects and mechanisms of Chinese herbal medicine in the treatment of psoriasis

ETHNOPHARMACOLOGICAL RELEVANCE

Psoriasis is a chronic inflammatory dermatosis related to high morbidity and mortality. The incidence of psoriasis is increasing in recent decades. Some patients with psoriasis are anxious about the underlying side effects of synthetic drugs they are on. Therefore, they are eager to seek alternative and efficient therapy, such as Chinese herbal medicine (CHM). Researchers have found some CHM provides best source for the development of anti-psoriatic drugs because of their structural diversity and fewer adverse reactions. Some of CHM formulas or active constituents extracted from CHM have been rapidly developed into clinical drugs with good efficacy. At present, along with the CHM formulas, single CHM and its active components have been extensively accepted and utilized in the treatment of psoriasis, whose therapeutic mechanisms hitherto have not been thoroughly illustrated.

AIM OF THE STUDY

This review aimed to comprehensively summarize about the existing therapeutic mechanisms of CHM in the treatment of psoriasis and to provide a reference to develop future related studies in this field.

MATERIALS AND METHODS

Relevant literatures about how CHM treated psoriasis were acquired from published scientific studies (including PubMed, CNKI, Web of Science, Baidu Scholar, The Plant List, Elsevier and SciFinder). All plants appearing in the review have been included in The Plant List or Medicinal Plant Names Services (MPNS).

RESULTS

In this review, we collect numerous literatures about how CHM treats psoriasis via immune cells, signaling pathways and disease-related mediators and systematically elucidates potential mechanisms from the point of the suppression of oxidative stress, the inhibition of abnormal abnormal proliferation and differentiation, the inhibition of immune responses, and the suppression of angiogenesis.

CONCLUSIONS

Psoriasis is considered as a complicated disease caused by interaction among various mechanisms. The CHM formulas, single CHM and its active components have considerable positive reports about the treatment of psoriasis, which brings hope for a promising future of CHM in the clinical therapy of psoriasis. In the paper, we have concluded that the existing therapeutic mechanisms of CHM in the treatment of psoriasis.

Topical administration of the secretome derived from human amniotic epithelial cells ameliorates psoriasis-like skin lesions in mice

BACKGROUND

Psoriasis is a chronic inflammatory skin disease. Tissue stem cells have exhibited a therapeutic effect on psoriatic mice. However, the therapeutic effect of topical administration of the secretome derived from tissue stem cells on psoriasis has not been reported.

METHODS

The secretome from human amniotic epithelial cells (AEC-SC) and human umbilical cord mesenchymal stem cells (UMSC-SC) was topically administrated on the back of imiquimod-induced psoriasis-like mice. Subsequently, we observed the skin lesions and skin inflammation of psoriasis-like mice. Next, we further analyzed the paracrine factors in AEC-SC and UMSC-SC by protein chips. Lastly, the effect of the crucial paracrine factor was investigated by imiquimod-induced psoriasis-like mice.

RESULTS

We found that AEC-SC had a better therapeutic effect on attenuating psoriasis-like skin lesions including skin scales, skin redness and skin thickness than UMSC-SC, and it had a better regulatory effect on keratinocyte hyperproliferation and altered differentiation. Thus, we focused on AEC-SC. Further study showed that AEC-SC reduced the infiltration of neutrophils and interleukin-17-producing T cells. Next, the analysis of AEC-SC with protein chip revealed that the levels of anti-inflammatory factor interleukin-1 receptor antagonist (IL-1ra) were much higher in AEC-SC compared to that in UMSC-SC. More importantly, the beneficial effect of AEC-SC on psoriasis-like skin lesions and skin inflammation of mice were significantly impaired when neutralizing with IL-1ra antibody, while the recombinant human IL-1ra showed a less protective effect than AEC-SC.

CONCLUSIONS

The present study demonstrated that AEC-SC could efficiently ameliorate psoriasis-like skin lesions and skin inflammation and IL-1ra plays an essential role. Therefore, topical administration of AEC-SC may provide a novel strategy for treating psoriasis-like inflammatory skin diseases.

Psoriasis between Autoimmunity and Oxidative Stress: Changes Induced by Different Therapeutic Approaches

Psoriasis is defined as chronic, immune-mediated disease. Regardless of the development of new therapeutic approaches, the precise etiology of psoriasis remains unknown and speculative. The aim of this review was to systematize the results of previous research on the role of oxidative stress and aberrant immune response in the pathogenesis of psoriasis, as well as the impact of certain therapeutic modalities on the oxidative status in patients with psoriasis. Complex immune pathways of both the innate and adaptive immune systems appear to be major pathomechanisms in the development of psoriasis. Oxidative stress represents another important contributor to the pathophysiology of disease, and the redox imbalance in psoriasis has been reported in skin cells and, systemically, in plasma and blood cells, and more recently, also in saliva. Current immune model of psoriasis begins with activation of immune system in susceptible person by some environmental factor and loss of immune tolerance to psoriasis autoantigens. Increased production of IL-17 appears to be the most prominent role in psoriasis pathogenesis, while IL-23 is recognized as master regulator in psoriasis having a specific role in cross bridging the production of IL-17 by innate and acquired immunity. Other proinflammatory cytokines, including IFN-γ, TNF-α, IL-1β, IL-6, IL-22, IL-26, IL-29, or IL-36, have also been reported to play important roles in the development of psoriasis. Oxidative stress can promote inflammation through several signaling pathways. The most noticeable and most powerful antioxidative effects exert various biologics compared to more convenient therapeutic modalities, such as methotrexate or phototherapy. The complex interaction of redox, immune, and inflammatory signaling pathways should be focused on further researches tackling the pathophysiology of psoriasis, while antioxidative supplementation could be the solution in some refractory cases of the disease.

Ginsenoside Rg1 ameliorates psoriasis-like skin lesions by suppressing proliferation and NLRP3 inflammasomes in keratinocytes

As a common chronic skin disease, psoriasis is characterized by the involvement of congenital acquired inflammatory immune diseases. In the study, our results indicated the effect of ginsenoside Rg1 on psoriasis-like skin and the potential protection mechanisms that have not yet been investigated. In vivo, psoriasis-like skin mice model was induced by imiquimod (IMQ), then was treated by ginsenoside Rg1 for consecutive 4 weeks to evaluate its effect, respectively. In vitro, M5 cocktail treatment of human immortalized keratinocyte HaCaT-induced psoriasis-like skin cell model, which was exposed to ginsenoside Rg1. The inflammatory cell infiltration, expression level of keratinocyte proliferation marker Ki67, keratinocyte proliferation, inflammatory cytokines, and ROS/NLRP3 pathway-related proteins in vivo and in vitro were examined by hematoxylin and eosin, immunohistochemistry, ELISA, CCK-8, flow cytometry, and western blot. All results demonstrated that ginsenoside Rg1 attenuated the injury of psoriasis-like skin, which inhibited the proliferation of skin keratinocytes and the activation of NLRP3 inflammasome and the level of inflammatory factors such as IL-1β and IL-18, and decreased the level of Ki67, NLRP3, and caspase-1 in mice and HaCaT. Furthermore, NLRP3 overexpression attenuates the effect of ginsenoside Rg1 on M5 cocktail-induced proliferation and NLRP3 inflammasomes in HaCaT. These results demonstrated that ginsenoside Rg1 could suppress the ROS/NLRP3 pathway to treat psoriasis-like skin. PRACTICAL APPLICATIONS: This is the very first study to explore the efficacy of ginsenoside Rg1 against psoriasis-like skin lesions to reveal the underlying mechanism. In this paper, the detection of skin histopathological analysis, CCK-8, flow cytometry, western blot, and ELISA analysis shows that ginsenoside Rg1 has preventive effect on psoriasis caused by imiquimod or M5 cocktail through inhibiting NLRP3 inflammasome, which helps in the development of novel nutraceutical/functional food against psoriasis and thus could improve the quality of life in psoriasis patients.

Climatotherapy at the Dead Sea for psoriasis is a highly effective anti-inflammatory treatment in the short term; an immunohistochemical study

Climatotherapy is a well‐described treatment of psoriasis. Dead Sea climatotherapy (DSC) in Israel consists of intensive sun and Dead Sea bathing and is very effective in improving clinical and patient‐reported outcomes. However, the effect of DSC has not been widely studied. We aimed to investigate the effect of DSC on psoriasis skin using quantitative immunohistochemistry techniques and analysis of blood samples. Skin punch biopsies from 18 psoriasis patients from a previous cohort study were used. Biopsies were obtained from non‐lesional skin and from a psoriasis target lesion at baseline. A biopsy was acquired from the target lesion after DSC. Among patients who achieved complete visual clearance, a biopsy was also obtained at relapse. Blood samples were obtained at the same time points. We performed haematoxylin and eosin staining and quantitative immunohistochemical analysis of CD3, CD4, CD8, CD11c, CD103, CD163, CD207, forkhead box P3, Ki67 and myeloperoxidase. We performed blood tests of cholesterol, c‐reactive protein, glucose, haemoglobin A1c and triglycerides. All skin biomarkers except for CD207 were decreased after DSC. At relapse, none of the biomarkers were significantly different from the baseline lesional measurements. Total CD207 staining correlated with psoriasis area and severity index at baseline while CD163 staining correlated with psoriasis area and severity index at EOT. No changes were observed in selected blood tests during the study. Consistent with clinical results, DSC is highly effective in the short term almost normalising all investigated biomarkers. However, at relapse, biomarkers were upregulated to the baseline level.

Evolutionary context of psoriatic immune skin response

The skin is vital for protecting the body and perceiving external stimuli in the environment. Ability to adapt between environments is in part based on skin phenotypic plasticity, indicating evolved homeostasis between skin and environment. This homeostasis reflects the greater relationship between the body and the environment, and disruptions in this balance may lead to accumulation of susceptibility factors for autoimmune conditions like psoriasis. In this study, we examined the relationship between rapid, lineage-specific evolution of human skin and formation of psoriatic skin responses at the transcriptome level. We collected skin tissue biopsies from individuals with psoriasis and compared gene expression in psoriatic plaques to non-plaque psoriatic skin. We then compared these data with non-psoriatic skin transcriptome data from multiple primate species. We found 67 genes showing human-specific skin expression that are also differentially regulated in psoriatic skin; these genes are significantly enriched for skin barrier function, immunity and neuronal development. We identified six gene clusters with differential expression in the context of human evolution and psoriasis, suggesting underlying regulatory mechanisms in these loci. Human and psoriasis-specific enrichment of neuroimmune genes shows the importance of the ongoing evolved homeostatic relationship between skin and external environment. These results have implications for both evolutionary medicine and public health, using transcriptomic data to acknowledge the importance of an individual’s surroundings on their overall health.

The skin is important for protecting the body from the environment and perceiving external stimuli, creating an evolved balance between skin and the environment. We compare skin gene expression in humans with psoriasis to humans and non-human primates without psoriasis to better understand human-specific evolutionary changes in the skin. Our results suggest important evolutionary links between skin perception, human-specific skin development and immune response.

A Novel Curcumin-Mycophenolic Acid Conjugate Inhibited Hyperproliferation of Tumor Necrosis Factor-Alpha-Induced Human Keratinocyte Cells

Curcumin (CUR) has been used as adjuvant therapy for therapeutic application in the treatment of psoriasis through several mechanisms of action. Due to the poor oral bioavailability of CUR, several approaches have been developed to overcome the limitations of CUR, including the prodrug strategy. In this study, CUR was esterified with mycophenolic acid (MPA) as a novel conjugate prodrug. The MPA-CUR conjugate was structurally elucidated using FT-IR, ¹H-NMR, ¹³C-NMR, and MS techniques. Bioavailable fractions (BFs) across Caco-2 cells of CUR, MPA, and MPA-CUR were collected for further biological activity evaluation representing an in vitro cellular transport model for oral administration. The antipsoriatic effect of the BFs was determined using antiproliferation and anti-inflammation assays against hyperproliferation of tumor necrosis factor-alpha (TNF-α)-induced human keratinocytes (HaCaT). The BF of MPA-CUR provided better antiproliferation than that of CUR (p < 0.001). The enhanced hyperproliferation suppression of the BF of MPA-CUR resulted from the reduction of several inflammatory cytokines, including IL-6, IL-8, and IL-1β. The molecular mechanisms of anti-inflammatory activity were mediated by an attenuated signaling cascade of MAPKs protein, i.e., p38, ERK, and JNK. Our results present evidence for the MPA-CUR conjugate as a promising therapeutic agent for treating psoriasis by antiproliferative and anti-inflammatory actions.

Overcoming thickened pathological skin in psoriasis via iontophoresis combined with tight junction-opening peptide AT1002 for intradermal delivery of NF-κB decoy oligodeoxynucleotide

Transdermal delivery of nucleic acid therapeutics has been demonstrated to be effective for psoriasis treatment. We previously reported the utility of iontophoresis (IP) using weak electric current (0.3-0.5 mA/cm²) for intradermal delivery of nucleic acid therapeutics via weak electricity-mediated intercellular junction cleavage, and subsequent exertion of nucleic acid function. However, the thickened pathological skin in psoriasis hampers permeation of IP-administered macromolecules. Thus, approaches are needed to more strongly cleave intercellular spaces and overcome the psoriatic skin barrier. Herein, we applied a combination of tight junction-opening peptide AT1002 with IP, as synergistic effects of weak electricity-mediated intercellular junction cleavage and the tight junction-opening ability of AT1002 may help overcome thickened psoriatic skin and facilitate macromolecule delivery. Pretreatment with IP of an AT1002 analog exhibiting positively-charged moieties before fluorescence-labeled oligodeoxynucleotide IP resulted in the oligodeoxynucleotide permeation into psoriatic skin, whereas IP of the oligodeoxynucleotide alone did not. Moreover, psoriasis-induced upregulation of inflammatory cytokine mRNA levels was significantly suppressed by NF-κB decoy oligodeoxynucleotide IP combined with the AT1002 analog, resulting in amelioration of epidermis hyperplasia. These results suggest that synergistic effects of IP and an AT1002 analog can overcome thickened psoriatic skin and enable intradermal delivery of NF-κB decoy oligodeoxynucleotide for psoriasis treatment.

FUT8 Remodeling of EGFR Regulates Epidermal Keratinocyte Proliferation during Psoriasis Development

α-(1,6)-fucosyltransferase 8 (FUT8) is implicated in the pathogenesis of several malignancies, but its role in psoriasis is poorly understood. In this study, we show that FUT8 remodeling of EGFR plays a critical role in the development of psoriasis phenotypes. Notably, elevated FUT8 expression was associated with disease severity in the lesional epidermis of a patient with psoriasis. FUT8 gain of function promoted HaCaT cell proliferation, whereas short hairpin FUT8 reduced cell proliferation and induced a longer S phase with downregulation of cyclin A1 expression. Furthermore, cell proliferation, which is controlled by the activation of EGFR, was shown to be regulated by FUT8 core fucosylation of EGFR. Short hairpin FUT8 significantly reduced EGFR/protein kinase B signaling and slowed EGF‒EGFR complex trafficking to the perinuclear region. Moreover, short hairpin FUT8 reduced ligand-induced EGFR dimerization. Overactivated EGFR was observed in the lesional epidermis of both human patient and psoriasis-like mouse model, whereas conditional knockout of FUT8 in an IL-23 psoriasis-like mouse model ameliorated disease phenotypes and reduced EGFR activation in the epidermis. These findings implied that elevated FUT8 expression in the lesional epidermis is implicated in the development of psoriasis phenotypes, being required for EGFR overactivation and leading to keratinocyte hyperproliferation.

Insights into interplay of immunopathophysiological events and molecular mechanistic cascades in psoriasis and its associated comorbidities

Psoriasis is an inflammatory skin disease with complex pathogenesis and multiple etiological factors. Besides the essential role of autoreactive T cells and constellation of cytokines, the discovery of IL-23/Th17 axis as a central signaling pathway has unraveled the mechanism of accelerated inflammation in psoriasis. This has provided insights into psoriasis pathogenesis and revolutionized the development of effective biological therapies. Moreover, genome-wide association studies have identified several candidate genes and susceptibility loci associated with this disease. Although involvement of cellular innate and adaptive immune responses and dysregulation of immune cells have been implicated in psoriasis initiation and maintenance, there is still a lack of unifying mechanism for understanding the pathogenesis of this disease. Emerging evidence suggests that psoriasis is a high-mortality disease with additional burden of comorbidities, which adversely affects the treatment response and overall quality of life of patients. Furthermore, changing trends of psoriasis-associated comorbidities and shared patterns of genetic susceptibility, risk factors and pathophysiological mechanisms manifest psoriasis as a multifactorial systemic disease. This review highlights the recent progress in understanding the crucial role of different immune cells, proinflammatory cytokines and microRNAs in psoriasis pathogenesis. In addition, we comprehensively discuss the involvement of various complex signaling pathways and their interplay with immune cell markers to comprehend the underlying pathophysiological mechanism, which may lead to exploration of new therapeutic targets and development of novel treatment strategies to reduce the disastrous nature of psoriasis and associated comorbidities.

Circ_0061012 contributes to IL-22-induced proliferation, migration and invasion in keratinocytes through miR-194-5p/GAB1 axis in psoriasis

Psoriasis is a chronic inflammation-associated skin disorder featured by excessive proliferation and abnormal differentiation of keratinocytes. Here, we intended to investigate the role of circular RNA 0061012 (circ_0061012) in psoriasis progression. The expression of circ_0061012, SLMO2-ATP5E readthrough (SLMO2-ATP5E) messenger RNA (mRNA), microRNA-194-5p (miR-194-5p) and GRB2 associated binding protein 1 (GAB1) mRNA was determined by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation and metastasis were analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and transwell assays. Western blot assay was used to measure the protein levels of Ki67, matrix metallopeptidase 9 (MMP9) and GAB1. Dual-luciferase reporter assay and RNA immune co-precipitation (RIP) assay were used to verify the interaction between miR-194-5p and circ_0061012 or GAB1. Circ_0061012 abundance was significantly enhanced in lesional skin samples from psoriasis patients than that in normal skin specimens from healthy volunteers. Interleukin-22 (IL-22) treatment increased the expression of circ_0061012 in a dose-dependent manner. Circ_0061012 silencing alleviated IL-22-induced promoting effects in the proliferation, migration and invasion of HaCaT cells. Circ_0061012 interacted with miR-194-5p, and miR-194-5p knockdown counteracted circ_0061012 silencing-mediated influences in IL-22-induced HaCaT cells. GAB1 was a target of miR-194-5p in HaCaT cells, and miR-194-5p hampered proliferation and metastasis which were induced by IL-22 partly through targeting GAB1. Circ_0061012 elevated the expression of GAB1 through sponging miR-194-5p in HaCaT cells. Circ_0061012 accelerated IL-22-induced proliferation and metastasis in HaCaT cells through enhancing GAB1 expression via sponging miR-194-5p in psoriasis.

Going, Toll-like receptors in skin inflammation and inflammatory diseases

The Indian Ayurvedic physicians knew the concept of inflammation dating back to 1500 BC. The continuous progress in the immunology of inflammation has explained its undiscovered mechanisms. For example, the discovery of Toll-like receptor 4 (TLR4) in humans (1997) has revolutionized the field of infection biology and innate immunity. The laboratory mice have shown twelve TLRs and express TLR10 (CD290) as a disrupted pseudogene, and humans have ten functional TLRs. Now, it is well established that TLRs play a significant role in different infectious and inflammatory diseases. Skin inflammation and other associated inflammatory diseases, including atopic dermatitis (AD), acne vulgaris, and psoriasis, along with many skin cancers are major health problems all over the world. The continuous development in the immunopathogenesis of inflammatory skin diseases has opened the window of opportunity for TLRs in studying their role. Hence, the manuscript explores the role of different TLRs in the pathogenesis of skin inflammation and associated inflammatory diseases. The article starts with the concept of inflammation, its origin, and the impact of TLRs discovery on infection and inflammation biology. The subsequent section describes the burden of skin-associated inflammatory diseases worldwide and the effect of the geographical habitat of people affecting it. The third section explains skin as an immune organ and explains the expression of different TLRs on different skin cells, including keratinocytes, Langerhans cells (LCs), skin fibroblasts, and melanocytes. The fourth section describes the impact of TLRs on these cells in different skin-inflammatory conditions, including acne vulgaris, AD, psoriasis, and skin cancers. The article also discusses the use of different TLR-based therapeutic approaches as specific to these inflammatory skin diseases.

Thymol activates TRPM8-mediated Ca2+ influx for its antipruritic effects and alleviates inflammatory response in Imiquimod-induced mice

Psoriasis is a highly prevalent chronic dermatitis, characterized by widespread skin inflammation and spontaneous itch. Given the adverse reactions and drug dependence of current treatment, new drugs for psoriasis therapy are urgently needed. This study aims to explore the anti-psoriatic effects of thymol in imiquimod (IMQ) induced mice, and elucidate the potential mechanisms for its therapeutic activities. Thymol reduced the scratching behavior in IMQ mice, and activated Ca²⁺ response in cervical DRG neurons via TRPM8 channel. Also, thymol alleviated psoriasis-like skin lesions, and attenuated the enhanced infiltration of dermal neutrophils, dendritic cells (DCs) and Th17 cells. In addition, it reversed the upregulated expression of pro-inflammatory cytokines in the skin (TNF-α, IL-22, IL-23, IL-17A, IL-17F, IL-17C, IL-6, IL-1β and IFN-γ) and serum (TNF-α, IL-6, IL-1β, IL-17A and IFN-γ). Our results indicated that thymol can effectively ameliorate pruritus and the symptoms of psoriasis-like inflammation induced by IMQ, which makes it a promising drug for the treatment of psoriasis.

18β-Glycyrrhetinic acid induces human HaCaT keratinocytes apoptosis through ROS-mediated PI3K-Akt signaling pathway and ameliorates IMQ-induced psoriasis-like skin lesions in mice

Background

Psoriasis is a chronic inflammatory skin disease affecting 2–3% of the population worldwide. Hyperproliferative keratinocytes were thought to be an amplifier of inflammatory response, thereby sustaining persistence of psoriasis lesions. Agents with the ability to inhibit keratinocyte proliferation or induce apoptosis are potentially useful for psoriasis treatment. 18β-Glycyrrhetinic acid (GA), an active metabolite of glycyrrhizin, exhibits diverse pharmacological activities, including anti-inflammatory, anti-bacteria and anti-proliferation. The current study aims to evaluate the effects of GA on the proliferation and apoptosis of human HaCaT keratinocytes in vitro and investigate the effects of GA on the skin lesions of imiquimod (IMQ)-induced psoriasis-like mouse model in vivo.

Methods

Cell viability was assayed by CCK-8. Flow cytometry was performed to measure apoptosis and reactive oxygen species (ROS), with Annexin V-FITC/PI detection kit and DCFH-DA probe respectively. Caspase 9/3 activities were measured using caspase activity assay kits. The protein levels of Akt and p-Akt were determined using Western blotting. IMQ was applied to induce psoriasis-like skin lesions in mice. The histological change in mouse skin lesions was detected using hematoxylin and eosin (H&E) staining. The severity of skin lesions was scored based on Psoriasis Area Severity Index (PASI). RT-PCR was employed to examine the relative expression of TNF-α, IL-22 and IL-17A in mouse skin lesions.

Results

GA decreased HaCaT keratinocytes viability and induced cell apoptosis in a dose-dependent manner. In the presence of GA, intracellular ROS levels were significantly elevated. NAC, a ROS inhibitor, attenuated GA-mediated HaCaT keratinocytes growth inhibition and apoptosis. In addition, GA treatment remarkably decreased p-Akt protein level, which could be restored partially when cells were co-treated with GA and NAC. LY294002 (a PI3K inhibitor) treatment significantly enhanced GA-mediated cytotoxicity. Moreover, GA ameliorated IMQ-induced psoriasis-like skin lesions in mice.

Conclusions

GA inhibits proliferation and induces apoptosis in HaCaT keratinocytes through ROS-mediated inhibition of PI3K-Akt signaling pathway, and ameliorates IMQ-induced psoriasis-like skin lesions in mice.

In vitro evaluation of Naltrexone HCl 1% Topical Cream in XemaTop™ for psoriasis

Psoriasis is a multifactorial skin disease involving abnormal cell proliferation and inflammation; an efficacious topical treatment is yet to be identified. A formulation containing 1% Naltrexone HCl in XemaTop™ base was compounded, characterized and evaluated in vitro as a possible treatment for psoriasis. A three-dimensional psoriasis tissue model was exposed to the formulation for 2 or 5 days and analyzed for the level of markers of cellular proliferation, and inflammatory cytokine IL-6. Using immunohistochemical staining, the level of Ki67 protein significantly decreased in the drug-treated tissues. Western blot analysis showed 86% and 53% down-regulation of other proliferation markers PCNA and CYCLIN D1, respectively, after 5-day exposure. The pro-survival Wnt/β-catenin pathway was compromised as indicated by 57% decrease in the level of β-CATENIN and down-regulation of its down-stream targets including CYCLIN D1 (decreased by 53%), c-MYC (63%), c-JUN (92%) and MET (96%) proteins. Likewise, the PI3K/AKT/mTOR pathway was significantly inhibited by 1% Naltrexone HCl in XemaTop™, suggesting protein synthesis was affected. The production of IL-6 was inhibited by 70% in drug-treated tissues. These results suggest that the compounded drug is efficacious in down-regulating molecular markers associated with the pathogenesis of psoriasis. Low-dose Naltrexone in XemaTop™ was stable within 180 days when stored under refrigerated or ambient conditions. These results provide a basis for a clinical evaluation of 1% Naltrexone HCl in XemaTop™ in psoriasis patients.

Loss of TIPE2 Has Opposing Effects on the Pathogenesis of Autoimmune Diseases

Autoimmune diseases are a physiological state wherein immune responses are directed against and damage the body's own tissues. Cytokines secreted by infiltrated inflammatory cells contribute to the pathogenesis of autoimmune diseases. TIPE2, one of the four family members of Tumor necrosis factor-α induced protein-8 (TNFAIP8), is a negative regulator of innate and adaptive immunity and plays essential roles in the maintenance of immune tolerance. However, studies on the role of TIPE2 during the development of autoimmune diseases have generated contradictory results. In the current study, we sought to determine the role of TIPE2 during the development of IMQ-induced psoriasis and Experimental Autoimmune Uveitis (EAU) in mice. Our study revealed that, while TIPE2-deficiency alleviates psoriasis, it exacerbates the development of EAU. Further studies demonstrated that, although TIPE2-deficient T cells produced more IL-17A, they do not migrate efficiently to the local inflammatory site, i.e., the skin. This in turn led to the decreased IL-17A production in the skin and consequently reduced the severity of psoriasis in TIPE2-deficient mice. However, although TIPE2-deficient T cells still produced more IL-17A in EAU model, they migrate into the inflamed eye as efficient as TIPE2-sufficient T cells, and consequently exacerbates the development of EAU in TIPE2-deficient mice. Taken together, these results indicate that TIPE2 may either promote or suppress autoimmunity depending on the specific inflammatory microenvironment in different types of autoimmune diseases.

Etanercept reduces anxiety and depression in psoriasis patients, and sustained depression correlates with reduced therapeutic response to etanercept

BACKGROUND

The purpose of this study was to explore the correlation of anxiety and depression with therapeutic response to etanercept in psoriasis patients.

PATIENTS AND METHODS

One hundred and thirty-three patients with moderate-to-severe plaque psoriasis undergoing etanercept treatment were consecutively enrolled in this prospective cohort study, with all patients receiving etanercept treatment for 6 months. Psoriasis Area and Severity Index (PASI) score was evaluated at baseline (M0) and at month 1 (M1), M3 and M6 after treatment, and PASI 75/90 responses were calculated. The Hospital Anxiety and Depression Scale-Anxiety (HADS-A) score and the HADS-Depression (HADS-D) score were used to evaluate patients' anxiety and depression at M0, M1, M3 and M6. Sustained anxiety/depression were defined as HADS-A/D score≥8points both at M0 and M1.

RESULTS

Female gender and higher PASI score were associated with high risk of anxiety, while female gender, higher PASI score and longer disease duration were correlated with increased depression risk. After 6 months of etanercept treatment, 65.4% and 36.1% patients achieved PASI 75 and PASI 90 responses respectively, and both HADS-A and HADS-D scores were decreased. Most importantly, no correlation of baseline anxiety and depression with PASI 75 or PASI 90 response after 6 months of treatment was noted, while sustained depression, though not sustained anxiety, was observed to be correlated with decreased PASI 75 and PASI 90 responses.

CONCLUSIONS

Etanercept reduces anxiety and depression in psoriasis patients, and sustained depression correlates with reduced therapeutic response to etanercept.

Psoriasis: from Pathogenesis to Targeted Therapies

Over the last decade, the management of psoriasis has witnessed a paradigm shift. Thanks to the increasing knowledge about the pathogenesis of psoriasis, targeted treatments with monoclonal antibodies have been developed. These antibodies, which target the pathogenic TNF/IL-23/IL-17-pathway, were shown to be safe and efficacious in the management of most patients with moderate to severe chronic plaque psoriasis. Recently, molecular and genetic studies in pustular and erythrodermic psoriasis have identified additional inflammatory pathways, providing evidence that psoriasis is a heterogeneous disease and highlighting the requirement for personalized disease characterization for treatment optimization. In this article, we will review these advances and provide an update on the currently available treatment arsenal. We discuss the efficacy and safety profile of these individual therapeutic agents and describe their use in special indications. We will also describe the current understanding of psoriasis as a systemic disease associated with multiple comorbidities and illustrate its impact in the management of psoriatic patients. Finally, we discuss ongoing therapeutic developments as well as unmet needs and future perspectives in the field of psoriasis.

Chlamydial Plasmid-Encoded Protein pGP3 Inhibits Development of Psoriasis-Like Lesions in Mice

Background

The anti-microbial protein cathelicidin LL-37 plays an important role in the pathogenesis of psoriasis by inducing inflammation. Our previous study showed that the chlamydial plasmid-encoded protein pGP3 forms a stable complex with LL-37 to neutralize its pro-inflammatory activity. Here, we explored whether pGP3 can inhibit the development of lesions in mice with imiquimod-induced psoriasis.

Material/Methods

The protein pGP3 was expressed in bacteria and purified using glutathione-conjugated agarose beads and a precision protease. The ability of the purified pGP3 to block chemotaxis mediated by LL-37 was tested in vitro using bone marrow-derived neutrophils. The ability of the protein to inhibit the development of psoriasis-like lesions was tested by topically or subcutaneously administering pGP3 in doses of 10 or 50 μg to mice previously treated with imiquimod. Mouse skin was evaluated using the psoriasis area and severity index (PASI) score and photography. Skin biopsies were taken on day 8 and analyzed histologically.

Results

Purified pGP3 inhibited LL-37-mediated chemotaxis. Mice treated with 50 μg pGP3 showed clinical improvement with less severe erythema, infiltration, and scales; these mice also showed thinner dermis and less hyperkeratosis, parakeratosis, and inflammatory cell infiltration than mice treated with without 10 μg pGP3.

Conclusions

PGP3 can inhibit the development of psoriasis-like lesions in mice, possibly through its ability to bind LL-37. Future work should examine the mechanisms underlying this therapeutic effect.

Monoclonal antibodies inhibiting IL-12, -23, and -17 for the treatment of psoriasis

Psoriasis is a chronic, inflammatory, immune-mediated skin condition that affects 3 to 4% of the adult US population, characterized by well-demarcated, erythematous plaques with silver scale. Psoriasis is associated with many comorbidities including cardiometabolic disease and can have a negative impact on quality of life. The current armamentarium of psoriasis treatment includes topical therapies, phototherapy, oral immunosuppressive therapies, and biologic agents. Over the past 2 decades, there has been rapid development of novel biologic therapies for the treatment of moderate-to-severe plaque psoriasis. This article will review the role of IL-12, IL-23, and IL-17 in the pathogenesis of psoriasis and the monoclonal antibodies (ustekinumab, secukinumab, ixekizumab, brodalumab, guselkumab, tildrakizumab, and risankizumab) that target these cytokines in the treatment of this disease.

Microarray analysis of human keratinocytes from different anatomic sites reveals site-specific immune signaling and responses to human papillomavirus type 16 transfection

BACKGROUND

Stratified human keratinocytes (SHKs) are an essential part of mucosal innate immune response that modulates adaptive immunity to microbes encountered in the environment. The importance of these SHKs in mucosal integrity and development has been well characterized, however their regulatory immunologic role at different mucosal sites, has not. In this study we compared the immune gene expression of SHKs from five different anatomical sites before and after HPV16 transfection using microarray analyses.

METHODS

Individual pools of human keratinocytes from foreskin, cervix, vagina, gingiva, and tonsils (HFKs, HCKs, HVKs, HGKs and HTLKs) were prepared. Organotypic (raft) cultures were established for both normal and HPV16 immortalized HFKs, HCKs, HVKs, HGKs and HTLKs lines which stably maintained episomal HPV16 DNA. Microarray analysis was carried out using the HumanHT-12 V4 gene chip (Illumina). Immune gene expression profiles were obtained by global gene chip (GeneSifter) and Ingenuity pathway analysis (IPA) for each individual site, with or without HPV16 transfection.

RESULTS

We examined site specific innate immune response gene expression in SHKs from all five different anatomical sites before and after HPV16 transfection. We observed marked differences in SHK immune gene repertoires within and between mucosal tracts before HPV 16 infection. In addition, we observed additional changes in SHKs immune gene repertoire patterns when these SHKs were productively transfected with HPV16. Some immune response genes were similarly expressed by SHKs from different sites. However, there was also variable expression of non-immune response genes, such as keratin genes, by the different SHKs.

CONCLUSIONS

Our results suggest that keratinocytes from different anatomical sites are likely hard wired in their innate immune responses, and that these immune responses are unique depending on the anatomical site from which the SHKs were derived. These observations may help explain why select HPV types predominate at different mucosal sites, cause persistent infection at these sites, and on occasion, lead to HPV induced malignant and benign tumor development.

RNA-seq identifies a diminished differentiation gene signature in primary monolayer keratinocytes grown from lesional and uninvolved psoriatic skin

Keratinocyte (KC) hyper-proliferation and epidermal thickening are characteristic features of psoriasis lesions, but the specific contributions of KCs to plaque formation are not fully understood. This study used RNA-seq to investigate the transcriptome of primary monolayer KC cultures grown from lesional (PP) and non-lesional (PN) biopsies of psoriasis patients and control subjects (NN). Whole skin biopsies from the same subjects were evaluated concurrently. RNA-seq analysis of whole skin identified a larger number of psoriasis-increased differentially expressed genes (DEGs), but analysis of KC cultures identified more PP- and PN-decreased DEGs. These latter DEG sets overlapped more strongly with genes near loci identified by psoriasis genome-wide association studies and were enriched for genes associated with epidermal differentiation. Consistent with this, the frequency of AP-1 motifs was elevated in regions upstream of PN-KC-decreased DEGs. A subset of these genes belonged to the same co-expression module, mapped to the epidermal differentiation complex, and exhibited differentiation-dependent expression. These findings demonstrate a decreased differentiation gene signature in PP/PN-KCs that had not been identified by pre-genomic studies of patient-derived monolayers. This may reflect intrinsic defects limiting psoriatic KC differentiation capacity, which may contribute to compromised barrier function in normal-appearing uninvolved psoriatic skin.

Topical administration of reversible SAHH inhibitor ameliorates imiquimod-induced psoriasis-like skin lesions in mice via suppression of TNF-α/IFN-γ-induced inflammatory response in keratinocytes and T cell-derived IL-17

DZ2002, a reversible S-adenosyl-l-homocysteine hydrolase (SAHH) inhibitor with immunosuppressive properties and potent therapeutic activity against various autoimmune diseases in mice. The present study was designed to characterize the potential therapeutic effects of DZ2002 on murine model of psoriasis and reveal the correlated mechanisms. In this report, we demonstrated that in vitro, DZ2002 significantly decreased the expression of pro-inflammatory cytokines and adhesion molecule including IL-1α, IL-1β, IL-6, IL-8, TNF-α and ICAM-1 by inhibiting the phosphorylation of p38 MAPK, ERK and JNK in TNF-α/IFN-γ-stimulated HaCaT human keratinocytes. Topical administration of DZ2002 alleviated the imiquimod (IMQ)-induced psoriasis-like skin lesions and inflammation in mice, the therapeutic effect was comparable with the Calcipotriol. Moreover, the inflammatory skin disorder was restored by DZ2002 treatment characterized by reducing both of the CD3⁺ T cell accumulation and the psoriasis-specific cytokines expression. Further, we found that DZ2002 improved IMQ-induced splenomegaly and decreased the frequency of splenic IL-17-producing T cells. Our finding offered the convincing evidence that SAHH inhibitor DZ2002 might attenuate psoriasis by simultaneously interfering the abnormal activation and differentiation of keratinocytes and accumulation of IL-17-producing T cells in skin lesions.

How relevant are vascular endothelial growth factor and intercellular adhesion molecule in the systemic capillary leak syndrome of psoriasis?

Psoriasis is a chronic disease, characterized by erythematous scaly lesions, presented in eight different forms: plaques, guttate, pustular, erythrodermic, inverse, nail and scalp psoriasis, and psoriatic arthritis. Its development depends on genetic factors, external stimulus and immune response alteration.1 Proinflammatory cytokines such as TNF-alpha, IL-12 and 23 may also be involved. In the worst cases, systemic complications linked to endothelial alterations may occur. A literature review was conducted for a better understanding of what roles VEGF (vascular endothelial growth factor) and ICAM-1 (intercellular adhesion molecule) have, among other cytokines, in systemic capillary leak syndrome, involved in erythrodermic and pustular psoriasis, the most unstable forms of the disease.

Inhibition of IL-17-committed T cells in a murine psoriasis model by a vitamin D analogue

BACKGROUND

A better understanding of the means by which topical vitamin D analogues exert their therapeutic effect on psoriasis is of theoretical and practical importance.

OBJECTIVE

We sought to clarify whether and how the topical vitamin D analogue calcipotriol (CAL) controls the IL-17A-mediated pathogenesis of murine psoriasis-like dermatitis in vivo.

METHODS

Psoriasis-like dermatitis was induced by the topical application of an imiquimod (IMQ)-containing cream on the murine ear for 4 to 6 consecutive days. For topical CAL treatment, mice were treated daily with CAL solution on the ear before IMQ application.

RESULTS

Mice treated topically with CAL exhibited much milder IMQ-induced psoriasis-like dermatitis compared with vehicle-treated mice, with impaired accumulation of IL-17A-committed T (T17) cells in the lesional skin. The IMQ-induced upregulation of Il12b and Il23a was marked in the epidermis and was abrogated by CAL application, suggesting CAL-mediated suppression of IL-23 expression. CAL inhibited Il12b and Il23a expression by Langerhans cells ex vivo stimulated with IMQ and CD40 cross-linking. Topical CAL also inhibited T17 cell expansion in the draining lymph nodes of IMQ-treated skin, implying a possible effect on T17 cell-mediated dermatitis at distant sites. In fact, topical CAL application on the IMQ-treated left ear resulted in amelioration of T17 cell accumulation and psoriasis-like dermatitis in the right ear subsequently treated with IMQ.

CONCLUSION

Topical CAL can exert its antipsoriatic effect on CAL-treated lesions and, concomitantly, distant lesions by attenuating the T17 cell accumulation in both CAL-treated lesions and draining lymph nodes.

Psoriasis and Cardiovascular Risk-Do Promising New Biomarkers Have Clinical Impact?

Epidemiological studies suggest an increased prevalence of cardiovascular disease (CVD) in patients with psoriasis (PS). Therefore, emphasis has lately been laid on the necessity for clinical evaluation of the risk of CVD in these patients. The systemic inflammatory markers C-reactive protein (CRP) and interleukin- (IL-) 6, which have long been used to predict future CVD in the general population, are increased manyfold in patients with PS. Lipid abnormalities characterized by elevated triglycerides, low HDL cholesterol, and higher concentrations of LDL cholesterol and its oxidized form are also prevalent in patients. There is a need for additional laboratory markers for the assessment of cardiovascular status of patients with PS. Due to frequent comorbid overweight and obesity, biologically active compounds produced by adipocytes may have an impact on monitoring the status of the cardiovascular system of patients with PS. For this purpose, two adipokines, adiponectin and leptin, have been most extensively studied. The review focuses on some inflammatory and oxidative stress aspects in patients with PS through the analysis of the impact of prominent adipokines and oxidized low-density lipoprotein (oxLDL) to assess their eligibility for clinical practice as markers of CVD risk in patients with PS.

Monocyte subpopulations study in patients with plaque psoriasis

Psoriasis is a chronic and systemic, immune-mediated, inflammatory disease, mainly manifested by skin and / or joints lesions, presenting with a wide degree of clinical severity, but generally with great impact on patients' quality of life. Despite advances in the understanding of its pathogenesis, especially regarding the participation of T-lymphocytes and the key role of TNF, the triggering factor of the disease at the molecular level remains unknown, as well as the function of other cell populations. By presenting antigens to T-lymphocytes, monocytes assume an important role in both innate and adaptive immune response. In the last two decades, by using flow cytometry with antibodies against CD14 (receptor for lipopolysaccharide) and CD16 (low affinity receptor for IgG), human blood monocytes were classified into three subpopulations: classical (CD14++CD16-), intermediate (CD14++CD16+), and non-classical (CD14+CD16++). Under normal conditions the population of classical monocytes corresponds to about 85%, while intermediate to 5.4%, and nonclassical to 9.2%. However, intermediate and nonclassical subsets are increased in various inflammatory situations, such as moderate to severe asthma, colorectal cancer, and rheumatoid arthritis. Despite psoriasis being considered a disease of inflammatory nature, scarce studies evaluating the frequency of subpopulations of monocytes in psoriatic patients are found on current medical literature, and they are restricted to peripheral blood analysis. This study aims to identify the frequency of monocyte subpopulations in blood levels as well as lesional skin of plaque psoriasis patients, and to evaluate their association to cytokines, and clinical disease severity.

Roles of microRNAs in psoriasis: Immunological functions and potential biomarkers

MicroRNAs (miRNAs) are small non-coding RNA molecules, which function in RNA silencing and post-transcriptional regulation of gene expression. Psoriasis is an inflammatory skin disease characterized by the dysfunction of keratinocytes, with the immune dysregulation. We reviewed the recent studies on the roles of miRNAs in psoriasis and showed that miRNAs play key roles in psoriasis, including the regulation of hyperproliferation, cytokine and chemokine production in keratinocyte, as well as mediating immune dysfunction in psoriasis. Furthermore, miRNAs, particularly, circulating miRNAs may serve as novel biomarkers for diagnosis, monitoring therapy response and reflecting the disease severity. Thus, targeting specific miRNAs may be used to develop new therapeutic methods for psoriasis.

MicroRNA-194 regulates keratinocyte proliferation and differentiation by targeting Grainyhead-like 2 in psoriasis

MicroRNAs (miRNAs) are currently emerged as important regulators in psoriasis. Psoriasis is characterized by hyperproliferation and impaired differentiation of keratinocytes in skin lesions. miR-194 is a well-known regulator of cell proliferation and differentiation. However, the role of miR-194 in psoriasis pathogenesis remains unclear. In this study we aimed to investigate the role of miR-194 in keratinocyte hyperproliferation and differentiation. We found that miR-194 was significantly downregulated in psoriasis lesional skin. Overexpression of miR-194 inhibited the proliferation and promoted the differentiation of primary human keratinocytes, whereas miR-194 suppression promoted the proliferation and inhibited their differentiation. Bioinformatic analysis predicted that the Grainyhead-like 2 (GRHL2) was a target gene of miR-194, which we further validated with a dual-luciferase reporter assay, real-time quantitative polymerase chain reaction (RT-qPCR), and Western blot analysis. The effect of miR-194 on cell proliferation and differentiation was significantly reversed by overexpression of GRHL2. Moreover, the expression of miR-194 and GRHL2 was inversely correlated in psoriasis lesional skin. Taken together, our results suggest that miR-194 inhibits the proliferation and promotes the differentiation of keratinocytes through targeting GRHL2. The downregulation of miR-194 expression may contribute to the pathogenesis of psoriasis and targeting miR-194 may represent a novel and potential therapeutic strategy for psoriasis.

Serum amyloid A, an acute phase protein, stimulates proliferative and proinflammatory responses of keratinocytes

OBJECTIVES

Serum amyloid A (SAA), an acute phase protein, is highly expressed in psoriatic lesions but its function is not fully understood. The aim of this study was to explore its role in activation of keratinocytes.

MATERIALS AND METHODS

Real-time PCR and immunofluorescence were performed to examine SAA expression in imiquimod (IMQ)-induced psoriasis-like mice. In vivo function of SAA was examined by treating psoriasis-like mice with SAA neutralising antibody. Cell viability was monitored using the CCK-8 assay. Real-time PCR was performed to determine expression of genes associated with differentiation and inflammation. Ki67⁺ percentage and immunological markers were analysed by flow cytometry. Involvement of formyl peptide receptor-like 1 (FPRL1) in SAA signal transduction was determined by RNA interference. Binding of SAA and FPRL1 was examined by co-immunoprecipitaion. Western blotting was conducted to assess phosphorylation of downstream signalling molecules.

RESULTS

SAA was highly expressed in skin lesions of IMQ-treated psoriasis-like mice and neutralising SAA attenuated epidermal hyperplasia and inflammation. SAA in vitro promoted keratinocyte proliferation and expression of immunological mediators, while inhibiting differentiation. Effects of SAA on keratinocyte proliferation and inflammation were mediated by FPRL1, as well as activation of the PI3K/Akt pathway.

CONCLUSIONS

These observations indicate that SAA/FPRL1 contributed to pathogenesis of psoriasis by promoting keratinocyte proliferation and inflammation, thus providing a potential therapeutic target for disease therapy.

Eczema as an adverse effect of anti-TNFα therapy in psoriasis and other Th1-mediated diseases: a review

INTRODUCTION

There have been rare reports of eczema occurring as an adverse effect of anti-tumor necrosis factor-alpha (TNFα) therapy.

METHODS

A literature search was conducted on PubMed for articles describing new onset or worsening of preexisting eczema during anti-TNFα therapy for the treatment of various inflammatory diseases.

RESULTS

Eczema as an adverse effect of anti-TNFα therapy may occur in approximately 5-20% of patients with various Th1-mediated inflammatory diseases such as psoriasis, inflammatory arthritis and inflammatory bowel disease. Personal history of atopy appears to increase this risk. Out of the anti-TNFα agents indicated for the treatment of moderate-to-severe psoriasis, infliximab may be more strongly associated with development or exacerbation of preexisting eczema.

DISCUSSION

Inhibitors of key mediators in the Th1 pathway such as TNFα are successful therapeutic targets for the treatment of various inflammatory conditions such as psoriasis, psoriatic arthritis, rheumatoid arthritis and inflammatory bowel disease. Blocking the Th1 pathway may create an imbalance favoring increased activity of the opposing Th2 pathway implicated in inflammatory conditions such as eczema. Further research is needed to better understand the role of the Th1/Th2 balance in various inflammatory diseases and how the immunologic environment is affected by immunotherapies.

Differential effectiveness of selected non-psychotropic phytocannabinoids on human sebocyte functions implicates their introduction in dry/seborrhoeic skin and acne treatment

Acne is a common skin disease characterized by elevated sebum production and inflammation of the sebaceous glands. We have previously shown that a non-psychotropic phytocannabinoid ((-)-cannabidiol [CBD]) exerted complex anti-acne effects by normalizing 'pro-acne agents'-induced excessive sebaceous lipid production, reducing proliferation and alleviating inflammation in human SZ95 sebocytes. Therefore, in this study we aimed to explore the putative anti-acne effects of further non-psychotropic phytocannabinoids ((-)-cannabichromene [CBC], (-)-cannabidivarin [CBDV], (-)-cannabigerol [CBG], (-)-cannabigerovarin [CBGV] and (-)-Δ(9) -tetrahydrocannabivarin [THCV]). Viability and proliferation of human SZ95 sebocytes were investigated by MTT and CyQUANT assays; cell death and lipid synthesis were monitored by DilC1 (5)-SYTOX Green labelling and Nile Red staining, respectively. Inflammatory responses were investigated by monitoring expressions of selected cytokines upon lipopolysaccharide treatment (RT-qPCR, ELISA). Up to 10 μm, the phytocannabinoids only negligibly altered the viability of the sebocytes, whereas high doses (≥50 μm) induced apoptosis. Interestingly, basal sebaceous lipid synthesis was differentially modulated by the substances: CBC and THCV suppressed it, and CBDV had only minor effects, whereas CBG and CBGV increased it. Importantly, CBC, CBDV and THCV significantly reduced arachidonic acid (AA)-induced 'acne-like' lipogenesis. Moreover, THCV suppressed proliferation, and all phytocannabinoids exerted remarkable anti-inflammatory actions. Our data suggest that CBG and CBGV may have potential in the treatment of dry-skin syndrome, whereas CBC, CBDV and especially THCV show promise to become highly efficient, novel anti-acne agents. Moreover, based on their remarkable anti-inflammatory actions, phytocannabinoids could be efficient, yet safe novel tools in the management of cutaneous inflammations.

Galectin-7 Regulates Keratinocyte Proliferation and Differentiation through JNK-miR-203-p63 Signaling

Galectin-7, a member of the β-galactoside-binding protein family, is primarily expressed in stratified epithelial cells, including keratinocytes. There is information in the literature suggesting a role for this protein in regulation of keratinocyte survival and growth, but the underlying mechanism remains relatively unknown. Moreover, its expression pattern in the epidermis suggests that it is also involved in the regulation of keratinocyte differentiation. Here, we demonstrate that galectin-7 knockdown results in reduced differentiation and increased proliferation of keratinocytes. Using microarray and deep-sequencing analyses, we found that galectin-7 positively and negatively regulates microRNA (miR)-203 and miR-146a expression, respectively. We show that galectin-7 regulates keratinocyte differentiation and proliferation through miR-203 but not miR-146a. A knockdown of either galectin-7 or miR-203 in keratinocytes increases expression of p63, an essential transcription factor involved in skin development. Rescue of miR-203 expression in a galectin-7 knockdown model reduces p63 expression to baseline. Increased galectin-7 expression upregulates c-Jun N-terminal kinase (JNK) protein levels, which is required for miR-203 expression. Finally, we establish that galectin-7 can be associated with JNK1 and protect it from ubiquitination and degradation. Thus, our data suggest an intracellular function of galectin-7: regulation of keratinocyte proliferation and differentiation through the JNK1-miR-203-p63 pathway.

MiR-217 is down-regulated in psoriasis and promotes keratinocyte differentiation via targeting GRHL2

MiR-217 is a well-known tumor suppressor, and its down-regulation has been shown in a wide range of solid and leukaemic cancers. However, the biological role of miR-217 in psoriasis pathogenesis, especially in keratinocyte hyperproliferation and differentiation, is not clearly understood. In this study, we found the expression of miR-217 was markedly down-regulated in psoriasis keratinocytes of psoriatic patients. In addition, overexpression of miR-217 inhibited the proliferation and promoted the differentiation of primary human keratinocytes. On the contrary, inhibition of endogenous miR-217 increased cell proliferation and delayed differentiation. Furthermore, Grainyhead-like 2 (GRHL2) was identified as a direct target of miR-217 by luciferase reporter assay. The expression of miR-217 and GRHL2 was inversely correlated in both transfected keratinocytes and in psoriasis lesional skin. Moreover, knocking down GRHL2 expression by siRNA enhanced keratinocyte differentiation. Taken together, our results demonstrate a role for miR-217 in the regulation of keratinocyte differentiation, partially through the regulation of GRHL2.