The Genetic Basis of Psoriasis

The Potential of CRISPR-Guided Therapies in the Dermatology Clinic

Over the past decade, CRISPR has rapidly made its way from the bench to the bedside, providing a newfound therapeutic avenue to not only treat genetic diseases but also permanently cure them. Although there are several clinical trials in early stages, there are so far no CRISPR-based clinical trials for cutaneous disease. In this review, we describe multiple cutaneous diseases that represent ideal targets for CRISPR-based therapeutics owing to known single gene‒causing mutations. We also explore the potential of CRISPR nucleases to treat inflammatory disorders such as eczema and psoriasis, which are not classically categorized as genodermatoses. We describe the therapeutic solutions for these diseases that are guided by various CRISPR-associated (Cas) effector proteins, for example, using Cas9 to permanently edit the DNA of somatic cells, Cas3 to target foreign DNA to combat viral/bacterial skin infections, and Cas13 to edit mutated RNA transcripts in diseases where permanent DNA editing is untenable. Furthermore, we discuss various drug delivery modalities for CRISPR therapeutics, including transdermal patches and microneedles, which are uniquely suited for dermatological diseases. In summary, we highlight the potential of CRISPR-based therapeutics to revolutionize the treatment of cutaneous disease with a goal of being accessible to the practicing dermatologist.

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.

Roles of clock genes in the pathogenesis of Parkinson's disease

Parkinson's disease (PD) is a common motor disorder that has become increasingly prevalent in the ageing population. Recent works have suggested that circadian rhythms disruption is a common event in PD patients. Clock genes regulate the circadian rhythm of biological processes in eukaryotic organisms, but their roles in PD remain unclear. Despite this, several lines of evidence point to the possibility that clock genes may have a significant impact on the development and progression of the disease. This review aims to consolidate recent understanding of the roles of clock genes in PD. We first summarized the findings of clock gene expression and epigenetic analyses in PD patients and animal models. We also discussed the potential contributory role of clock gene variants in the development of PD and/or its symptoms. We further reviewed the mechanisms by which clock genes affect mitochondrial dynamics as well as the rhythmic synthesis and secretion of endocrine hormones, the impairment of which may contribute to the development of PD. Finally, we discussed the limitations of the currently available studies, and suggested future potential studies to deepen our understanding of the roles of clock genes in PD pathogenesis.

Bioengineered Efficacy Models of Skin Disease: Advances in the Last 10 Years

Models of skin diseases, such as psoriasis and scleroderma, must accurately recapitulate the complex microenvironment of human skin to provide an efficacious platform for investigation of skin diseases. Skin disease research has been shifting from less complex and less relevant 2D (two-dimensional) models to significantly more relevant 3D (three-dimensional) models. Three-dimensional modeling systems are better able to recapitulate the complex cell–cell and cell–matrix interactions that occur in vivo within skin. Three-dimensional human skin equivalents (HSEs) have emerged as an advantageous tool for the study of skin disease in vitro. These 3D HSEs can be highly complex, containing both epidermal and dermal compartments with integrated adnexal structures. The addition of adnexal structures to 3D HSEs has allowed researchers to gain more insight into the complex pathology of various hereditary and acquired skin diseases. One method of constructing 3D HSEs, 3D bioprinting, has emerged as a versatile and useful tool for generating highly complex HSEs. The development of commercially available 3D bioprinters has allowed researchers to create highly reproducible 3D HSEs with precise integration of multiple adnexal structures. While the field of bioengineered models for study of skin disease has made tremendous progress in the last decade, there are still significant efforts necessary to create truly biomimetic skin disease models. In future studies utilizing 3D HSEs, emphasis must be placed on integrating all adnexal structures relevant to the skin disease under investigation. Thorough investigation of the intricate pathology of skin diseases and the development of effective treatments requires use of highly efficacious models of skin diseases.

Nanotechnology-based medicinal products and patents: a promising way to treat psoriasis

Psoriasis is an autoimmune skin disorder that is characterised by chronic inflammation and erythematous scaly patches. It has a significant impact on the patient's quality of life and can cause psychological stress. There are several aspects which cause psoriasis for instance, environmental issues, immune disorders, bacterial infections, and genetic issues. Plentiful therapeutic means or treatments are accessible, but not any of them can completely and effectively cure psoriasis without hindering patient compliance. Hence, it becomes challenging to discover a new drug moiety or any drug delivery method to cure psoriasis. Conventional treatment of psoriasis involves anti-inflammatory agents, immune suppressants, phototherapy, and biologic treatment, those were given in different forms such as topical, oral, or systemic formulations, but these all were unsuccessful to accomplish complete reduction of psoriasis as well as causing adverse side effects. In terms of dose frequency, doses, efficacy, and side effects, nanotechnology-based new formulations are the most promising prospects for addressing the challenges and limits associated with present psoriasis formulations. Hence, our major goal of this review is to present various advanced nanotechnological approaches for effective topical treatment of psoriasis. In short, nano-formulations continue to be formed as very promising modality in the treatment of psoriasis as they suggest improved penetration, targeted delivery, increased safety, and efficacy.

Paeoniflorin inhibits proliferation and migration of psoriatic keratinocytes via the lncRNA NEAT1/miR-3194-5p/Galectin-7 axis

To investigate the mechanism underlying the effect of paeoniflorin (PF) on the proliferation and migration of psoriatic keratinocytes. The expressions of long noncoding RNA NEAT1, miR-3194-5p and Galectin-7 in skin tissues from psoriatic patients and healthy controls were detected. Psoriatic HaCat cells were used to investigate the function of NEAT1 and Galectin-7 as well as the effect and mechanism of PF in psoriasis. MTT, colony formation and scratch assays were used to assess the proliferation and migration of psoriatic HaCat cells. Dual-luciferase reporter assay was used to validate the interactions among NEAT1, miR-3194-5p and Galectin-7. NEAT1 and Galectin-7 were lowly expressed and miR-3194-5p was highly expressed in psoriatic patients. PF suppressed the proliferation and migration of psoriatic HaCat cells by elevating the expressions of NEAT1 and Galectin-7. NEAT1 positively mediated the expression of Galectin-7 by targeting miR-3194-5p. PF controls the proliferation and migration of psoriatic HaCat cells via the NEAT1/miR-3194-5p/Galectin-7 axis.

Effect of diet and weight loss on the severity of psoriasis

Psoriasis is one of the most common chronic inflammatory skin diseases, constituting a significant health and socioeconomic problem. Despite numerous therapeutic options, the results of treatment often remain insufficient. This may be due to the lack of compliance with medical prescriptions and patients’ limited knowledge of their disease. Psoriatic patient's skin well-being is affected by many factors, including lifestyle. The course of the disease is affected by obesity, improper diet, and stimulants. Often these factors coexist. Excessive weight gain in psoriasis can be caused by a decrease in physical activity, caused by feelings of social stigma, coexistence of psoriatic arthritis, depression, and increased alcohol consumption. Several studies have confirmed that the average fat, protein, and calorie content in the diet of a patient with psoriasis are above the recommended norms. On the other hand, adhering to a low calorie, reducing diet results in a clinically significant improvement in the Psoriasis Area Severity Index (PASI) and patients’ quality of life (i.e., reduction of Dermatology Life Quality Index [DLQI]). Weight reduction caused by diet and exercise reduces the severity of skin lesions, even in people who have not achieved improvement after general treatment. Therefore, it is important to educate the patient about the nature of the disease at the very beginning of treatment. Patients with moderate to severe forms of the disease are predisposed to the development of cardiovascular diseases, obesity, diabetes, and anxiety. That is why plaque psoriasis requires a comprehensive treatment and a holistic approach to the patient.

Protective association exhibited by a single nucleotide polymorphism of the IFIH1 gene in patients with psoriasis: A case-control study

Introduction

Psoriasis is a chronic inflammatory dermatosis, a with variable clinical presentation and whose multifactorial etiology carries an essential genetic component. Multiple genetic variations associated with psoriasis have been described around the world. However, these variants are unknown among the Colombian population. This study aimed to evaluate the single nucleotide polymorphism rs10930046 (His460Arg) in the IFIH1 gene and its ssociation with the development of psoriasis in a Colombian population.

Methods

An observational, unmatched, case-control study was performed, including 51 patients with psoriasis and 151 population controls, all with self-reported Paisa ancestry (from the Antioquia region). All individuals were genotyped for the single nucleotide polymorphism rs10930046 (His460Arg) in the IFIH1 gene, and its association with psoriasis was pursued. Both groups were demographically characterized, and cases were also assessed for clinical variables.

Results

Through the allelic association analysis, cases were found to have a lower frequency of the single nucleotide polymorphism rs10930046 (His460Arg) in the IFIH1 gene than controls; 5% versus 22.67%, respectively. There were no significant differences in age or sex. We also found that psoriasis vulgaris was the most common variant (78%), that about half of the cases had nail psoriasis (56%), 19.6% had psoriatic arthritis, and that 45% had some comorbidity.

Conclusions

The results obtained from this study confirm that carriers of the single nucleotide polymorphism rs10930046 (His460Arg) in the IFIH1 gene have a decreased risk of developing psoriasis.

Evaluation of the relationship of IL-17A and IL-17F gene polymorphisms with the response to treatment in psoriatic patients using biological drugs: a case-control study in patients in Eastern Turkey

Introduction

IL-17A and IL-17F cytokines have important roles in the pathogenesis of psoriasis.

Aim

To examine the associations of IL-17A rs2275913 and IL-17F rs763780 variants with the development of psoriasis and whether these polymorphisms affect the responsiveness of biological agents.

Material and methods

In our case-controlled study, which included 83 psoriatic patients who were treated with different biological agents and 69 healthy controls, we genotyped IL-17A rs2275913 and IL-17F rs763780 variants using TaqMan probes.

Results

We did not observe statistically significant changes in genotype frequencies of IL-17A rs2275913 (p = 0.922) and IL-17F rs763780 (p = 0.621) variants between patient and control groups. Although we did not find any association between these polymorphisms and the development of psoriasis, statistical analyses showed that individuals with the IL-17A AA genotype had shorter disease duration (9.09 ±6.82, p = 0.020) and AA genotype frequency was higher in patients who used single conventional treatment (34.6%; p = 0.025). IL17A/rs2275913 variant in terms of disease duration, it was observed that individuals with AA genotype had a shorter disease duration (less than 10 years) (p = 0.009). For patients with PASI90 and PASI100 response, the IL-17A AA genotype was significantly higher (p = 0.015). On the other hand, we did not detect any statistically significant correlation between variants and response to biological agents.

Conclusions

According to our results, we may suggest that rs2275913 variant seems to be associated with disease duration, use of single conventional treatment and responsiveness of PASI90 and PASI100 however both variants have no effect on the susceptibility to psoriasis in the population of Eastern Turkey.

Cytokine alterations in psoriasis: an updated review

INTRODUCTION

Psoriasis is a chronic immune-mediated disease affecting 125 million people globally. It is characterized by erythematous plaques in the skin, covered by silvery scales. However, non-cutaneous manifestations (e.g., joint symptoms in psoriatic arthritis) and a high prevalence of other immune-mediated diseases such as inflammatory bowel diseases reflect its systemic nature. So far, research on psoriasis pathogenesis has improved our knowledge of the roles of the immune system, and cytokines play significant roles in immune responses.

AREAS COVERED

Herein, we review cytokine changes in psoriasis patients. Moreover, we will investigate the possible relationships between disease severity and cytokines alongside describing cytokine alterations in psoriasis patients with other comorbidities. Lastly, we will discuss the biologics and their effects on cytokines in psoriasis patients.

EXPERT OPINION

Psoriasis could develop various clinical types and clinical manifestations in people. It is an immune-mediated disease, and these manifestations are associated with different impaired cytokines. Imbalanced cytokines could lead to abnormal keratinocytes, neovascularization, and inflammation in psoriasis patients. So, a better understanding of the cytokine roles can help one choose a specific cytokine-targeting biologic to treat psoriasis. Moreover, these cytokines may be used as a severity marker for following up with these patients.

Association analysis of MALAT1 polymorphisms and risk of psoriasis among Iranian patients

MALAT1 is a long non-coding transcript that affects immune reactions, thus being involved in the pathoaetiology of immune-related conditions. We investigated the associations between two genetic variants in MALAT1 and susceptibility to psoriasis in the Iranian population. The G allele of rs619586 has been shown to be less common among cases versus controls (odds ratios (OR; 95% confidence intervals (CI)) = 0.57 (0.36-0.9)), adjusted p = .02). This single nucleotide polymorphism has been associated with the risk of psoriasis in a dominant model (AG + GG vs. AA: OR (95% CI) = 0.56 (0.35-0.92), adjusted p = .04) as well as log-additive model (OR (95% CI) = 0.59 (0.38-0.92), adjusted p = .04). The rs3200401 was not associated with psoriasis in any of the supposed inheritance models. This study potentiates rs619586 as a risk locus for psoriasis in the Iranian population.

Macrophage migration inhibitory factor gene polymorphisms (SNP -173 G>C and STR-794 CATT5-8) confer risk of plaque psoriasis: A case-control study

BACKGROUND

Macrophage inhibitory factor (MIF) is a pro-inflammatory cytokine secreted by several cells, including those in the immune system and the skin. The MIF gene contains the SNP -173 G> C and STR -794 CATT5-8 polymorphisms in the promoter region capable of affecting its activity. Our objective was to investigate the MIF polymorphisms as a risk factor for plaque psoriasis (PP) in the Mexican population.

METHODS

We genotyped both MIF polymorphism (rs5844572 and rs755622) in 224 PP patients with a clinical and histopathological diagnosis and 232 control subjects (CS) by the PCR-RFLP method. MIF serum levels were determined by an ELISA kit.

RESULTS

We found significant differences in the genotypic and allelic frequencies for the MIF -173 G>C polymorphism; carriers of the GC genotype (OR 1.51, 95% CI 1.026-2.228, p = 0.03) and the C allele (OR 1.34, 95% CI 1.005-1.807, p = 0.04) had higher odds to present with PP. Moreover, the 6C haplotype was associated with PP risk (OR 2.10, 95% CI 1.22-3.69, p < 0.01). Also, the -173 CC genotype was associated with high MIF serum levels (p < 0.05).

CONCLUSIONS

The -173 GC genotype and the 6C haplotype of the MIF polymorphisms are associated with susceptibility to PP in the Mexican population.

Current Concepts of Psoriasis Immunopathogenesis

Psoriasis is a recurrent, chronic, immune-mediated, systemic inflammatory disease of the skin, joints, and other organic systems. After atopic dermatitis, chronic stationary psoriasis is the most common inflammatory skin disease, affecting an average of 2-4% of the world's population. The disease carries a significant burden due to its numerous comorbidities and the major impact on patients' social and emotional aspects of life. According to current knowledge, psoriasis is a multifactorial disease that occurs in genetically predisposed individuals under various environmental factors, which trigger an immune response disorder with a series of complex inflammatory cascades. The disease is initiated and maintained by mutual interaction of the innate and adaptive immune cells, primarily dendritic cells, T lymphocytes, and keratinocytes, whose leading role alternates at different stages of the disease, consisting mainly in the IL-23/Th17 pathway. Inflammatory events result in consequent epidermal and dermal changes and evolution of the characteristic psoriatic phenotype, respectively. This paper aims to present a comprehensive overview of current knowledge on psoriasis genetic and environmental etiological factors, immunopathogenesis, and the leading cellular and cytokine participants in the inflammatory pathways of this disease.

Impact of ABCG2 Gene Polymorphism on the Predisposition to Psoriasis

Psoriasis is a chronic inflammatory disease which is caused by the interaction between genetic and environmental factors. Evidence shows an association of psoriasis with co-morbidities including cardiovascular diseases, metabolic syndrome and hyperuricemia. Genome-wide association studies have revealed that the ABCG2 gene encoding ATP-binding cassette G2 protein was associated with inflammation and higher serum urate concentrations. In this study, we aimed to evaluate the role of ABCG2 gene polymorphisms on the susceptibility to psoriasis. The genotype distribution of two ABCG2 single nucleotide polymorphisms (SNPs), rs2231142 and rs2231137, was examined in 410 psoriasis patients and 1,089 gender-matched non-psoriasis controls. We found that heterozygotes (GT) for rs2231142 was associated with a decreased risk of psoriasis (p = 0.001; adjusted OR = 0.532; 95% CI, 0.370–0.765) after adjusting for age, as compared with homozygotes for the major allele (GG). Subjects who carried at least one polymorphic allele (homozygote or heterozygote for the minor allele) were less susceptible to psoriasis (p = 0.002; adjusted OR = 0.594; 95% CI, 0.249–0.823) and bearing higher serum urate levels (p = 0.026) than those homozygous for the major allele. Our results indicated that the ABCG2 gene polymorphism was associated with the risk of psoriasis.

Increased Skin Clearance and Quality of Life Improvement with Brodalumab Compared with Ustekinumab in Psoriasis Patients with Aggravating Lifestyle Factors

Introduction

Obesity, smoking, and alcohol consumption are prevalent in psoriasis patients and have been associated with increased disease severity and reduced treatment adherence and response. This post hoc analysis of pooled data from the phase 3 AMAGINE-2 and -3 trials compared the efficacy of brodalumab versus ustekinumab in psoriasis patients with aggravating and potentially treatment-confounding lifestyle risk factors.

Methods

This post hoc analysis evaluated complete skin clearance, as measured by a 100% reduction of Psoriasis Area and Severity Index (PASI100) and quality of life (QoL), as measured by a Dermatology Life Quality Index (DLQI) score of 0/1, by the presence of risk factors (obesity, tobacco or alcohol use). A competing risk model assessed cumulative incidence over 52 weeks with outcomes of PASI100 or inadequate response.

Results

This analysis included 929 patients (brodalumab 210 mg, n = 339; ustekinumab, n = 590) with moderate-to-severe psoriasis. At week 52, odds ratios (95% confidence intervals [CIs]) for complete clearance with brodalumab versus ustekinumab were 2.50 (1.14–5.46, P = 0.0186), 4.64 (2.80–7.69, P < 0.0001), 2.06 (1.25–3.40, P = 0.0045), and 2.55 (0.55–11.91, P = 0.2117) in patients with no, one, two, or three risk factors, respectively. Corresponding odds ratios (ORs) (95% CIs) for DLQI 0/1 with brodalumab versus ustekinumab were 1.72 (0.78–3.79, P = 0.1883), 2.49 (1.54–4.02, P < 0.0002), 1.57 (0.97–2.54, P = 0.0666), and 2.07 (0.45–9.57, P = 0.3438). The 52-week cumulative incidence of patients achieving PASI100 was consistently higher for brodalumab versus ustekinumab, regardless of number of risk factors (P < 0.0001 for one or two risk factors and P = 0.0029 for three risk factors).

Conclusions

Higher levels of complete skin clearance and QoL were achieved and maintained with brodalumab versus ustekinumab in patients with moderate-to-severe psoriasis, regardless of the presence of lifestyle risk factors.

Clinical Trial Registration

AMAGINE-2 (NCT01708603); AMAGINE-3 (NCT01708629).

Supplementary Information

The online version contains supplementary material available at 10.1007/s13555-021-00618-5.

Identifying Novel Psoriatic Disease Drug Targets Using a Genetics-Based Priority Index Pipeline

BACKGROUND

Despite numerous genome-wide association studies conducted in psoriasis and psoriatic arthritis, only a small fraction of the identified genes has been therapeutically targeted.

OBJECTIVE

We sought to identify and analyze potential therapeutic targets for psoriasis and psoriatic arthritis (PsA) using the priority index (Pi), a genetics-dependent drug target prioritization approach.

METHODS

Significant genetic variants from GWAS for psoriasis, PsA, and combined psoriatic disease were annotated and run through the Pi pipeline. Potential drug targets were identified based on genomic predictors, annotation predictors, pathway enrichment, and pathway crosstalk.

RESULTS

Several gene targets were identified for psoriasis and PsA that demonstrated biological associations to their respective diseases. Some are currently being explored as potential therapeutic targets (i.e. ICAM1, NF-kB, REV3L, ADRA1B for psoriasis; CCL11 for PsA); others have not yet been investigated (i.e. LNPEP, LCE3 for psoriasis; UBLCP1 for PsA). Additionally, many nodal points of potential intervention were identified as promising therapeutic targets. Of these, some are currently being studied such as TYK2 for psoriasis, and others have yet to be explored (i.e. PPP2CA, YAP1, PI3K, AKT, FOXO1, RELA, CSF2, IFNGR1, IFNGR2 for psoriasis; GNAQ, PLCB1, GNAI2 for PsA).

CONCLUSION

Through Pi, we identified data-driven candidate therapeutic gene targets and pathways for psoriasis and PsA. Given the sparse PsA specific genetic studies and PsA specific drug targets, this analysis could prove to be particularly valuable in the pipeline for novel psoriatic therapies.

Characterisation of the nail microbiome in psoriatic and nonpsoriatic patients with onychomycosis

BACKGROUND

Onychomycosis (OM) is the most common infectious nail disease, and it occurs frequently in patients with psoriasis. Microbial community shifts have been suggested to play a role in psoriasis and fungal infection occurrence.

OBJECTIVES

To investigate and compare nail microbial community compositions in psoriatic and nonpsoriatic patients with OM.

METHODS

Toenail samples were collected from nonpsoriatic patients with OM, psoriatic patients with nail psoriasis (NP) and OM, patients with only NP and healthy controls. Bacterial and fungal community compositions were analysed by amplicon sequencing of the V3-V4 regions of the 16S rDNA gene and the ITS1 region, respectively.

RESULTS

Psoriatic OM patients had higher bacterial and fungal alpha diversities. Taxonomic analysis revealed a significantly lower relative abundance of Trichophyton rubrum (32.88% vs 82.18%, p < .001) and an increased trend of the abundance of Candida in psoriatic patients with OM than in nonpsoriatic patients. Nonpsoriatic patients with OM had a higher abundance of Staphylococcus than healthy controls (59.66% vs 45.76%, p < .05). Trichophyton, Alternaria and Malassezia could accurately differentiate psoriatic and nonpsoriatic patients with OM, with an area under the curve (AUC) of 0.86. The severity of OM was positively correlated with the relative abundance of Trichophyton rubrum. Further, Trichophyton was positively correlated with Staphylococcus and negatively correlated with Corynebacterium, Anaerococcus, Malassezia and Alternaria.

CONCLUSIONS

The nail microbiome in psoriatic patients with OM has distinct bacterial and fungal signatures, suggesting that different dysbiosis is associated with the pathogenesis of OM in psoriatic and nonpsoriatic patients.

Novel archetype in psoriasis management bridging molecular dynamics in exploring novel therapies

Psoriasis is an autoimmune chronic inflammatory condition of skin affecting 125 million populaces around the globe. It is implicated as a result of multifaceted phenomena involving various cell and subcell activities with the aid of numerous cellular and molecular components including signaling aisle and regulatory proteins owing to the development of such hyperproliferative dermatological conditions. This involves a deeply complex and conflicting pathology owing to genetic and immunological deviations resulting from the unusual presentation of different signaling pathways and regulatory proteins. Explorations of these biomarkers and intervention of molecular and cellular processes in psoriasis are yet to be investigated and could be an exceptional aspect for understanding pathology with successful targeting of disease. In the presented study, we have integrated molecular insights, including signaling molecules, pathways, and proteins implicated in pathogenesis, and we have attempted to link this knowledge to the targeting of these phenomena in order to manage the conditions precisely. Further, therapeutic delivery approaches for targeting distinct layers of skin have also been investigated based on the application of different nanocarriers for successful psoriasis treatment.

Impact of isoflavone genistein on psoriasis in in vivo and in vitro investigations

Genistein is applied worldwide as an alternative medicament for psoriasis (Ps) because of its anti-inflammatory activity and perceived beneficial impact on the skin. Hereby, we report our in vivo and in vitro investigations to supplement scientific research in this area. The reduction of clinical and biochemical scores in mild to moderate Ps patients taking genistein, its safety, good tolerability with no serious adverse events or discontinuations of treatment, no dose-limiting toxicities, negligible changes in pharmacodynamic parameters and remarkable serum interleukin level alterations were documented in this study. A certain regression of the Ps phenotype was visible, based on photo-documented Ps lesion evaluation. Through in vitro experiments, we found that genistein reduced IL-17A and TNF-α induced MAPK, NF-κB, and PI3K activation in normal human epidermal keratinocytes. Moreover, at the mRNA level of genes associated with the early inflammatory response characteristic for Ps (CAMP, CCL20, DEFB4A, PIK3CA, S100A7, and S100A9) and key cellular signalling (MTORC1 and TFEB), we showed that this isoflavone attenuated the increased response of IL-17A- and TNF-α-related pathways. This allows us to conclude that genistein is a good candidate for Ps treatment, being attractive for co-pharmacotherapy with other drugs.

Psoriasis and Cardiovascular Disease: Novel Mechanisms and Evolving Therapeutics

PURPOSE OF REVIEW

Psoriasis is a chronic inflammatory skin condition that is associated with increased cardiovascular risk compared to those without psoriasis. This review will cover emerging mechanisms of cardiovascular risk, key pathways targeted with biologic therapies, and the current evidence on therapies to modulate this risk in patients with psoriasis.

RECENT FINDINGS

Recent scientific work has highlighted mechanisms that contribute to this enhanced risk, including the role of vascular endothelial dysfunction, platelet activation, dyslipidemia, and increased cardiometabolic comorbidities. Newer biologic and targeted synthetic therapies have transformed psoriasis treatment with high rates of clinical remission and durable skin disease control now possible. Epidemiological evidence suggests that many of these therapies may lower cardiovascular risk in psoriasis, although prospective interventional data is lacking (or mixed). Recently, caution has also been raised that some treatments may negatively affect cardiovascular risk. Overall, the current data suggests a positive or neutral ability to reduce cardiovascular risk for TNF, IL-17A, and IL-12/23p40 inhibitors, but current evidence remains conflicting for anti-IL-23/p19 and JAK inhibitors. More studies that include prospective cohorts, larger number of patients, treatment duration, and validated surrogate outcomes are needed to better evaluate the role of biologic therapies on cardiovascular risk in psoriasis.

Purinergic Signaling and Inflammasome Activation in Psoriasis Pathogenesis

Psoriasis is a chronic inflammatory disease of the skin associated with systemic and joint manifestations and accompanied by comorbidities, such as metabolic syndrome and increased risk of cardiovascular disease. Psoriasis has a strong genetic basis, but exacerbation requires additional signals that are still largely unknown. The clinical manifestations involve the interplay between dendritic and T cells in the dermis to generate a self-sustaining inflammatory loop around the TNFα/IL-23/IL-17 axis that forms the psoriatic plaque. In addition, in recent years, a critical role of keratinocytes in establishing the interplay that leads to psoriatic plaques’ formation has re-emerged. In this review, we analyze the most recent evidence of the role of keratinocytes and danger associates molecular patterns, such as extracellular ATP in the generation of psoriatic skin lesions. Particular attention will be given to purinergic signaling in inflammasome activation and in the initiation of psoriasis. In this phase, keratinocytes’ inflammasome may trigger early inflammatory pathways involving IL-1β production, to elicit the subsequent cascade of events that leads to dendritic and T cell activation. Since psoriasis is likely triggered by skin-damaging events and trauma, we can envisage that intracellular ATP, released by damaged cells, may play a role in triggering the inflammatory response underlying the pathogenesis of the disease by activating the inflammasome. Therefore, purinergic signaling in the skin could represent a new and early step of psoriasis; thus, opening the possibility to target single molecular actors of the purinome to develop new psoriasis treatments.

The Role of Epigenetic Factors in Psoriasis

Psoriasis is a chronic, systemic, immune-mediated disease with an incidence of approximately 2%. The pathogenesis of the disease is complex and not yet fully understood. Genetic factors play a significant role in the pathogenesis of the disease. In predisposed individuals, multiple trigger factors may contribute to disease onset and exacerbations of symptoms. Environmental factors (stress, infections, certain medications, nicotinism, alcohol, obesity) play a significant role in the pathogenesis of psoriasis. In addition, epigenetic mechanisms are considered result in modulation of individual gene expression and an increased likelihood of the disease. Studies highlight the significant role of epigenetic factors in the etiology and pathogenesis of psoriasis. Epigenetic mechanisms in psoriasis include DNA methylation, histone modifications and non-coding RNAs. Epigenetic mechanisms induce gene expression changes under the influence of chemical modifications of DNA and histones, which alter chromatin structure and activate transcription factors of selected genes, thus leading to translation of new mRNA without affecting the DNA sequence. Epigenetic factors can regulate gene expression at the transcriptional (via histone modification, DNA methylation) and posttranscriptional levels (via microRNAs and long non-coding RNAs). This study aims to present and discuss the different epigenetic mechanisms in psoriasis based on a review of the available literature.

Downregulation of interleukin 36γ and its cleaver cathepsin G following treatment with narrow-band ultraviolet B phototherapy in psoriasis vulgaris

BACKGROUND

Growing evidence suggests the important role of IL-36 in the pathogenesis of psoriasis. Cathepsin G is a neutrophil-derived protease that can activate IL-36γ.

OBJECTIVE

To assess the expression of IL-36γ and cathepsin G in psoriasis and to quantify the impact of treatment with narrow-band ultraviolet B phototherapy (NB-UVB) on their levels.

METHODS

This case-control study involved 26 patients with moderate-severe psoriasis and 25 healthy volunteers. Psoriasis patients eligible for phototherapy received 24 NB-UVB sessions. Punch skin biopsies were obtained from all participants at recruitment and after phototherapy from patients. Real-time PCR was utilized for quantitative assessment of IL-36γ and cathepsin G expression in tissue samples.

RESULTS

The expression of IL-36γ and cathepsin G was significantly higher in psoriasis before NB-UVB therapy compared to controls (p < .001). Both proteins decreased significantly with clinical improvement following NB-UVB therapy compared to baseline (p < .001). However, their expression after treatment was still higher than controls (p < .001).

CONCLUSION

IL-36γ and cathepsin G expression is upregulated in psoriatic lesions, supporting their role as mediators of inflammation in psoriasis. Downregulation of IL-36γ and cathepsin G is a possible mechanism for psoriasis improvement after NB-UVB therapy. IL-36 and cathepsin G can be considered as therapeutic targets for psoriasis.

Interleukin 36 expression in psoriasis variants and other dermatologic diseases with psoriasis-like histopathologic features

BACKGROUND

Elevated epidermal interleukin (IL)-36 expression distinguishes psoriasis from eczematous dermatitis, but other psoriasiform dermatitides (PDs) have not been thoroughly investigated for IL-36 expression. In this study, we assess the IL-36 staining pattern (IL36-SP) in psoriasis variants and other PDs including lichen simplex chronicus (LSC), prurigo nodularis (PN), lichen planus (LP), tinea, pityriasis rubra pilaris (PRP), mycosis fungoides (MF), pemphigus foliaceus (PF), acute generalized exanthematous pustulosis (AGEP), impetigo (IMP), and syphilis (SY).

METHODS

IL-36 immunostaining was performed on 307 cases of psoriasis and various PDs. IL36-SP in the upper epidermis was graded on a scale of 0-4.

RESULTS

High IL36-SP occurred in all variants of psoriasis, as well as in AGEP, PRP, PN, tinea, IMP, and LP (P > 0.05). SY, PF, LSC, and MF showed a lower IL36-SP (P ≤ 0.05) compared with psoriasis.

CONCLUSION

All variants of psoriasis exhibit high IL36-SP. IL-36 staining can assist in differentiating MF, PF, SY, and LSC from psoriasis, particularly MF and LSC, which have consistent low IL-36 expression. AGEP, PRP, tinea, IMP, PN, and LP exhibit high IL-36 expression similar to psoriasis, indicating Th17 activation in these diseases.

Therapeutic Development Based on the Immunopathogenic Mechanisms of Psoriasis

Psoriasis, a complex inflammatory autoimmune skin disorder that affects 2–3% of the global population, is thought to be genetically predetermined and induced by environmental and immunological factors. In the past decades, basic and clinical studies have significantly expanded knowledge on the molecular, cellular, and immunological mechanisms underlying the pathogenesis of psoriasis. Based on these pathogenic mechanisms, the current disease model emphasizes the role of aberrant Th1 and Th17 responses. Th1 and Th17 immune responses are regulated by a complex network of different cytokines, including TNF-α, IL-17, and IL-23; signal transduction pathways downstream to the cytokine receptors; and various activated transcription factors, including NF-κB, interferon regulatory factors (IRFs), and signal transducer and activator of transcriptions (STATs). The biologics developed to specifically target the cytokines have achieved a better efficacy and safety for the systemic management of psoriasis compared with traditional treatments. Nevertheless, the current therapeutics can only alleviate the symptoms; there is still no cure for psoriasis. Therefore, the development of more effective, safe, and affordable therapeutics for psoriasis is important. In this review, we discussed the current trend of therapeutic development for psoriasis based on the recent discoveries in the immune modulation of the inflammatory response in psoriasis.

So close, and yet so far away: The dichotomy of the specific immune response and inflammation in psoriasis and atopic dermatitis

Characterization of the complex interplay between cytokines, chemokines and microorganisms has led to a better understanding of the pathogenesis of both psoriasis and AD and resulted in new therapeutics targeting distinct immune responses. Psoriasis and AD share many characteristics: they are highly prevalent, chronic, cause primarily skin inflammation, but are associated with comorbidities, and come with a devastating quality of life due to itch and stigmatization. However, the pathogenesis of psoriasis and AD is opposing - psoriasis is dominated by a Th17 immune response that causes neutrophil migration, induction of innate immunity and exaggerated epithelial metabolism. Leading cytokines of this Th17 immune response are IL-17A and F, IL-22 and TNF-a. AD is characterized by Th2 immunity characterized by the signature cytokines IL-4 and IL-13 leading to an impaired epidermal barrier, dampened innate immunity and eosinophil migration. This review compares genetics, microbiome and T-cell infiltrate and resulting epithelial response in psoriasis and AD. Whilst the antagonistic course of psoriasis and AD is confirmed by response to specific biologics targeting the key cytokines of inflammation in psoriasis and AD, respectively, clinically overlapping phenotypes are challenging in our daily clinical practice. We conclude this review by summarizing what is known about these mixed phenotypes and how the identification of clinically relevant endotypes and molecular-driven decision-making is the next step in the field of dermato-immunology.

Psoriasis is associated with fissured tongue but not geographic tongue: a prospective, cross-sectional, case-control study

BACKGROUND AND OBJECTIVES

It has been postulated that psoriasis is associated with tongue lesions and geographic tongue might be "oral psoriasis". However, reports are inconclusive, prevalence rates vary and data for Europe are sparse. In this prospective case-control study we investigated the point-prevalence of tongue conditions in an Austrian cohort.

PATIENTS AND METHODS

Psoriasis patients and healthy volunteers were assessed regarding tongue and skin lesions, age, sex, smoking habits, allergies, onset of psoriasis, PASI scores and anti-psoriatic treatment.

RESULTS

We included 173 psoriasis patients, 58 women, 115 men (median age: 50 [37-60] years), and 173 volunteers, 79 women, 94 men (median age: 54 [43-64] years). Overall, 95 subjects had allergies, 64 psoriasis patients and 50 volunteers were smokers. Median age at onset of psoriasis was 26 (12-40) years, the median PASI score was 2 (0-4.1), most patients received ustekinumab (n = 47). Fissured tongue was significantly associated with psoriasis (25 [14.4 %] psoriasis patients, 13 [7.5 %] volunteers; P = 0.04). Geographic tongue was present in four individuals of each group (2.3%) and associated with smoking (P = 0.01) but not with psoriasis.

CONCLUSIONS

Overall, we found a low point-prevalence of tongue lesions in this Austrian cohort. Psoriasis was associated with fissured tongue but not with geographic tongue. Thus, we cannot corroborate the hypothesis that geographic tongue is an oral manifestation of psoriasis.

Serum Levels of miR-146a in Patients with Psoriasis

BACKGROUND

Psoriasis is an immune-mediated disease with interactions between genetic and environmental factors. An increasing number of studies are demonstrating the importance of microRNAs (miRNAs) in the pathogenesis of psoriasis. miR-146a, a dominant negative regulator of inflammation, has been consistently reported as overexpressed in the skin and peripheral blood mononuclear cells (PBMCs) of patients with psoriasis. Expression and/or function of this miRNA is highly influenced by genetic variations, some of which have already been associated with susceptibility to psoriasis.

OBJECTIVE

We sought to study the importance of miR-146a in patients with moderate-to-severe psoriasis and to understand the impact of rs57095329 and rs2910164 polymorphisms in a psoriatic Portuguese population.

METHODS

miR-146a circulating levels were quantified using molecular biology techniques in 99 patients with moderate-to-severe psoriasis (35 female, 64 male; age 47.4 ± 10.9 years) and 78 healthy individuals (52 female, 26 male; age 42.4 ± 10.1 years). miRNA expression was correlated with clinicopathological features as well as with genetic data such as the presence of human leukocyte antigen (HLA)-C*0602 allele and two miR-146a polymorphisms (rs2910164 and rs57095329).

RESULTS

miR-146a serum levels were 3.7-fold higher in patients with psoriasis than in controls (p < 0.0001, area under the curve [AUC] 0.75; 95% confidence interval [CI] 0.66-0.83). Of note, miR-146a circulating levels positively correlated with Psoriasis Area and Severity Index (p < 0.05) and body surface area (p < 0.05) indexes. No variations in miR-146a levels were observed with rs2910164 and rs57095329 genotypes.

CONCLUSION

Circulating miR-146a levels were upregulated in patients with psoriasis, especially in those with active disease. To the best of our knowledge, this is the largest study with a homogenous psoriasis population, and our data could shed light on the pathogenesis of psoriasis, paving the way for new avenues for disease treatment.

HLA-Cw1 and Psoriasis

Psoriasis is a chronic inflammatory skin condition with regional and ethnic differences in its prevalence and clinical manifestations. Human leukocyte antigen (HLA)-Cw6 is the disease allele conferring the greatest risk to psoriasis, but its prevalence is lower in Asian individuals. Recent studies have found associations between HLA-Cw1 and some Asian populations with psoriasis, especially Southern Chinese. HLA-Cw6 was associated with type I early-onset psoriasis, guttate psoriasis, Koebner phenomenon, and better response to methotrexate, interleukin (IL)-12/23, IL-17, and IL-23 targeting drugs. In contrast, HLA-Cw1 positivity has been associated with erythrodermic psoriasis, pustular psoriasis, and the axial type of psoriatic arthritis. Furthermore, HLA-Cw1 was more frequently associated with high-need patients who did not respond to conventional therapies. No known trigger factor nor autoantigen has been identified for HLA-Cw1 positivity. However, HLA-Cw1 has been linked to some viral agents. For example, cytotoxic T lymphocytes recognize multiple cytomegalovirus pp65-derived epitopes presented by HLA alleles, including HLA-C*01:02. In addition, cytomegalovirus can lead to severe exacerbation of psoriatic skin disease. The proposed interaction between viral infection, HLA-Cw1, and psoriasis is through the killer cell immunoglobulin-like receptors of natural killer cells. Given the diverse nature of psoriasis pathogenesis and the difference in HLA-Cw prevalence in different racial groups, more studies are needed to confirm the role of HLA-Cw1 in psoriasis.

Potential herbal constituents for psoriasis treatment as protective and effective therapy

Psoriasis is a multifactorial and chronic skin disorder. It is a recurrent disease that requires incessant therapy. Psoriasis treatment includes topical and systemic routes using synthetic drugs that lead to severe unwanted adverse effects. Herbal therapy is widely used for thousands of years in countries like China and India. The use of herbal therapy in the developed region enhanced to a great extent and showed better efficacy towards psoriasis alone or as adjuvant to synthetic therapy. Herbal medicines have gained great attention in the treatment of psoriasis due to their lesser side effects compared to synthetic drugs. In this review, the various plant sources which have been found effective in psoriasis and can be used to develop novel therapeutics have been discussed. The mechanisms by which the phytoconstituents elicit anti-psoriatic activity and various research studies that have proven the effectiveness of these natural products have also been compiled in this review.

Pathophysiology of psoriasis: A review

Psoriasis is a complex chronic inflammatory skin disease caused by the dynamic interplay between multiple genetic risk foci, environmental risk factors, and excessive immunological abnormalities. Psoriasis affects approximately 2% of the population worldwide, and dramatic advances have been achieved in the understanding and treatment options for psoriasis. Recent progress in biological therapies has revealed the fundamental roles of tumor necrosis factor-α, interleukin (IL)-23p19, and the IL-17A axis together with skin-resident immune cells and major signal transduction pathways in the pathogenesis of psoriasis. In addition to IL-17-producing T helper17 cells, innate lymphoid cell (ILC)3 induces psoriasis rashes directly without T-cell/antigen interaction in response to the released antimicrobial peptides from activated keratinocytes and inflammatory cytokines. ILC3 typically expresses retinoic acid receptor-related orphan receptor gamma t in the nucleus, matures in the presence of IL-7 and IL-23, and produces IL-17 and IL-22. The number of ILC3s is increased in the blood, psoriasis rash, and even in nonrash areas of psoriatic skin. Psoriasis is significantly associated with cardiovascular disease, metabolic syndrome, and inflammatory disorders, particularly the severe type. The similarity of enterobacteria in the psoriasis gut to that in diabetic patients may be related to its pathogenesis. In the current review, we focus on the pathophysiology of psoriasis in the accelerated immunological inflammatory loop, danger signal from keratinocytes, and cytokines, particularly IL-17 and IL-23p19. In addition, pathophysiological speculation with regard to morphology has been supplemented. Finally, the differences and similarities between psoriasis and atopic dermatitis are discussed.

Systemic pharmacological treatments for chronic plaque psoriasis: a network meta-analysis

BACKGROUND

Psoriasis is an immune-mediated disease for which some people have a genetic predisposition. The condition manifests in inflammatory effects on either the skin or joints, or both, and it has a major impact on quality of life. Although there is currently no cure for psoriasis, various treatment strategies allow sustained control of disease signs and symptoms. Several randomised controlled trials (RCTs) have compared the efficacy of the different systemic treatments in psoriasis against placebo. However, the relative benefit of these treatments remains unclear due to the limited number of trials comparing them directly head-to-head, which is why we chose to conduct a network meta-analysis.

OBJECTIVES

To compare the efficacy and safety of non-biological systemic agents, small molecules, and biologics for people with moderate-to-severe psoriasis using a network meta-analysis, and to provide a ranking of these treatments according to their efficacy and safety.

SEARCH METHODS

For this living systematic review we updated our searches of the following databases monthly to September 2020: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and Embase. We searched two trials registers to the same date. We checked the reference lists of included studies and relevant systematic reviews for further references to eligible RCTs.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of systemic treatments in adults (over 18 years of age) with moderate-to-severe plaque psoriasis or psoriatic arthritis whose skin had been clinically diagnosed with moderate-to-severe psoriasis, at any stage of treatment, in comparison to placebo or another active agent. The primary outcomes of this review were: the proportion of participants who achieved clear or almost clear skin, that is, at least Psoriasis Area and Severity Index (PASI) 90 at induction phase (from 8 to 24 weeks after the randomisation), and the proportion of participants with serious adverse events (SAEs) at induction phase. We did not evaluate differences in specific adverse events.

DATA COLLECTION AND ANALYSIS

Several groups of two review authors independently undertook study selection, data extraction, 'Risk of bias' assessment, and analyses. We synthesised the data using pair-wise and network meta-analysis (NMA) to compare the treatments of interest and rank them according to their effectiveness (as measured by the PASI 90 score) and acceptability (the inverse of serious adverse events). We assessed the certainty of the body of evidence from the NMA for the two primary outcomes and all comparisons, according to CINeMA, as either very low, low, moderate, or high. We contacted study authors when data were unclear or missing. We used the surface under the cumulative ranking curve (SUCRA) to infer on treatment hierarchy: 0% (treatment is the worst for effectiveness or safety) to 100% (treatment is the best for effectiveness or safety).

MAIN RESULTS

We included 158 studies (18 new studies for the update) in our review (57,831 randomised participants, 67.2% men, mainly recruited from hospitals). The overall average age was 45 years; the overall mean PASI score at baseline was 20 (range: 9.5 to 39). Most of these studies were placebo-controlled (58%), 30% were head-to-head studies, and 11% were multi-armed studies with both an active comparator and a placebo. We have assessed a total of 20 treatments. In all, 133 trials were multicentric (two to 231 centres). All but two of the outcomes included in this review were limited to the induction phase (assessment from 8 to 24 weeks after randomisation). We assessed many studies (53/158) as being at high risk of bias; 25 were at an unclear risk, and 80 at low risk. Most studies (123/158) declared funding by a pharmaceutical company, and 22 studies did not report their source of funding. Network meta-analysis at class level showed that all of the interventions (non-biological systemic agents, small molecules, and biological treatments) were significantly more effective than placebo in reaching PASI 90. At class level, in reaching PASI 90, the biologic treatments anti-IL17, anti-IL12/23, anti-IL23, and anti-TNF alpha were significantly more effective than the small molecules and the non-biological systemic agents. At drug level, infliximab, ixekizumab, secukinumab, brodalumab, risankizumab and guselkumab were significantly more effective in reaching PASI 90 than ustekinumab and three anti-TNF alpha agents: adalimumab, certolizumab, and etanercept. Ustekinumab and adalimumab were significantly more effective in reaching PASI 90 than etanercept; ustekinumab was more effective than certolizumab, and the clinical effectiveness of ustekinumab and adalimumab was similar. There was no significant difference between tofacitinib or apremilast and three non-biological drugs: fumaric acid esters (FAEs), ciclosporin and methotrexate. Network meta-analysis also showed that infliximab, ixekizumab, risankizumab, bimekizumab, secukinumab, guselkumab, and brodalumab outperformed other drugs when compared to placebo in reaching PASI 90. The clinical effectiveness of these drugs was similar, except for ixekizumab which had a better chance of reaching PASI 90 compared with secukinumab, guselkumab and brodalumab. The clinical effectiveness of these seven drugs was: infliximab (versus placebo): risk ratio (RR) 50.29, 95% confidence interval (CI) 20.96 to 120.67, SUCRA = 93.6; high-certainty evidence; ixekizumab (versus placebo): RR 32.48, 95% CI 27.13 to 38.87; SUCRA = 90.5; high-certainty evidence; risankizumab (versus placebo): RR 28.76, 95% CI 23.96 to 34.54; SUCRA = 84.6; high-certainty evidence; bimekizumab (versus placebo): RR 58.64, 95% CI 3.72 to 923.86; SUCRA = 81.4; high-certainty evidence; secukinumab (versus placebo): RR 25.79, 95% CI 21.61 to 30.78; SUCRA = 76.2; high-certainty evidence; guselkumab (versus placebo): RR 25.52, 95% CI 21.25 to 30.64; SUCRA = 75; high-certainty evidence; and brodalumab (versus placebo): RR 23.55, 95% CI 19.48 to 28.48; SUCRA = 68.4; moderate-certainty evidence. Conservative interpretation is warranted for the results for bimekizumab (as well as mirikizumab, tyrosine kinase 2 inhibitor, acitretin, ciclosporin, fumaric acid esters, and methotrexate), as these drugs, in the NMA, have been evaluated in few trials. We found no significant difference between any of the interventions and the placebo for the risk of SAEs. Nevertheless, the SAE analyses were based on a very low number of events with low to moderate certainty for all the comparisons. Thus, the results have to be viewed with caution and we cannot be sure of the ranking. For other efficacy outcomes (PASI 75 and Physician Global Assessment (PGA) 0/1) the results were similar to the results for PASI 90. Information on quality of life was often poorly reported and was absent for several of the interventions.

AUTHORS' CONCLUSIONS

Our review shows that compared to placebo, the biologics infliximab, ixekizumab, risankizumab, bimekizumab, secukinumab, guselkumab and brodalumab were the most effective treatments for achieving PASI 90 in people with moderate-to-severe psoriasis on the basis of moderate- to high-certainty evidence. This NMA evidence is limited to induction therapy (outcomes were measured from 8 to 24 weeks after randomisation) and is not sufficient for evaluation of longer-term outcomes in this chronic disease. Moreover, we found low numbers of studies for some of the interventions, and the young age (mean age of 45 years) and high level of disease severity (PASI 20 at baseline) may not be typical of patients seen in daily clinical practice. Another major concern is that short-term trials provide scanty and sometimes poorly-reported safety data and thus do not provide useful evidence to create a reliable risk profile of treatments. We found no significant difference in the assessed interventions and placebo in terms of SAEs, and the evidence for all the interventions was of low to moderate quality. In order to provide long-term information on the safety of the treatments included in this review, it will also be necessary to evaluate non-randomised studies and postmarketing reports released from regulatory agencies. In terms of future research, randomised trials directly comparing active agents are necessary once high-quality evidence of benefit against placebo is established, including head-to-head trials amongst and between non-biological systemic agents and small molecules, and between biological agents (anti-IL17 versus anti-IL23, anti-IL23 versus anti-IL12/23, anti-TNF alpha versus anti-IL12/23). Future trials should also undertake systematic subgroup analyses (e.g. assessing biological-naïve participants, baseline psoriasis severity, presence of psoriatic arthritis, etc.). Finally, outcome measure harmonisation is needed in psoriasis trials, and researchers should look at the medium- and long-term benefit and safety of the interventions and the comparative safety of different agents. Editorial note: This is a living systematic review. Living systematic reviews offer a new approach to review updating, in which the review is continually updated, incorporating relevant new evidence as it becomes available. Please refer to the Cochrane Database of Systematic Reviews for the current status of this review.

The study of dry eye and meibomian glands in psoriasis

BACKGROUND

To investigate aqueous and lipid layers of the tear film as well as meibomian gland structure by meibography in psoriatic patients in the Iranian population.

METHODS

This case-control study was conducted on 31 psoriasis patients and 31 controls in Birjand University of Medical Sciences in 2018. The sampling method was available from the date of approval of the proposal in the Ethics Committee until it reached the sample size. After entering the study, patients were examined individually with a slit lamp. Then, Ocular Surface Disease Index (OSDI) score assessment, Schirmer test 1, lacrimal measurement with SM tube, tear break-up time (TBUT), and meibomian glands imaging by SBM Sistemi were done. Finally, the obtained data were entered into SPSS 15 software and analyzed at a significant level of less than 0.05.

RESULTS

The two groups were matched according to age and gender (p = 0.39 and p = 0.80; respectively). With the exception of the SM Tube score, the mean of all tear film and meibomian glands functional and structural parameters including Schirmer test 1, TBUT, and meibography were significantly different between patients and control groups. Moreover, the proportion of abnormal OSDI (OSDI ⩾ 13) and the dry eye was significantly higher in psoriasis patients.

CONCLUSIONS

Psoriasis is associated with dry eye as well as meibomian glands atrophy and dysfunction.

miR-617 Promotes the Growth of IL-22-Stimulated Keratinocytes Through Regulating FOXO4 Expression

Psoriasis is considered as a common chronic and relapsing inflammatory skin disease. MicroRNAs (miRNAs) were found to be related with psoriasis pathogenesis. Nevertheless, the function of miR-617 in psoriasis is still unclear. The miR-617 RNA level was detected using quantitative reverse transcription-PCR (qRT-PCR). Western blot analysis examined the protein level. Cell proliferation was analyzed via cell counting kit-8 (CCK-8) assay. Flow cytometry analysis detected cell cycle and apoptosis. The relationship between miR-617 and forkhead box protein O4 (FOXO4) was confirmed through dual luciferase assay. The miR-617 was up-regulated in psoriatic skin tissues and interleukin-22 (IL-22)-stimulated immortalized human keratinocyte HaCaT cells. Moreover, miR-617 mimics promoted proliferation, cell cycle, and suppressed apoptosis in IL-22-stimulated HaCaT cells. However, miR-617 inhibitor showed opposite effects. Additionally, FOXO4 was a target of miR-617. FOXO4 was down-regulated in psoriatic skin tissues and IL-22-stimulated HaCaT cells. Negative correlation between miR-617 and FOXO4 was identified. FOXO4 overexpression alleviated the effects of miR-617 proliferation, cell cycle and apoptosis in the IL-22-stimulated HaCaT cells. These results demonstrate that miR-617 increases the growth of IL-22-stimulated keratinocytes through targeting FOXO4, which provides a new therapeutic target for psoriasis.

Major histocompatibility complex (MHC) associations with diseases in ethnic groups of the Arabian Peninsula

Since the discovery of human leukocyte antigens (HLAs), the function of major histocompatibility complex (MHC) gene families in a wide range of diseases have been the subject of research for decades. In particular, the associations of autoimmune disorders to allelic variants and candidate genes encoding the MHC are well documented. However, despite decades of research, the knowledge of MHC associations with human disease susceptibility have been predominantly studied in European origin, with limited understanding in different populations and ethnic groups. This is particularly evident in countries and ethnic populations of the Arabian Peninsula. Human MHC haplotypes, and its association with diseases, of the variable ethnic groups of this region are poorly studied. This review compiled published manuscripts that have reported a list of autoimmune diseases (insulin-dependent diabetes mellitus, systemic lupus erythematosus, myasthenia gravis, rheumatoid arthritis, psoriasis vulgaris, and multiple sclerosis) associated with MHC class I and class II in the populations of the Arabian Peninsula, specifically Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, the United Arab Emirates, and Yemen. Data available was compared with other three ethnic groups, namely Caucasians, Asians, and Africans. The limited data available in the public domain on the association between MHC gene and autoimmune diseases highlight the challenges in the Middle Eastern region.

Insights into the pathogenesis of psoriatic arthritis from genetic studies

Psoriatic arthritis (PsA) is a relatively common inflammatory arthritis, a spondyloarthritis (SpA), that occurs most often in patients with psoriasis, a common immune-mediated inflammatory skin disease. Both psoriasis and PsA are highly heritable. Genetic and recent genomic studies have identified variants associated with psoriasis and PsA, but variants differentiating psoriasis from PsA are few. In this review, we describe recent developments in understanding the genetic burden of PsA, linkage, association and epigenetic studies. Using pathway analysis, we provide further insights into the similarities and differences between PsA and psoriasis, as well as between PsA and other immune-mediated inflammatory diseases, particularly ankylosing spondylitis, another SpA. Environmental factors that may trigger PsA in patients with psoriasis are also reviewed. To further understand the pathogenetic differences between PsA and psoriasis as well as other SpA, larger cohort studies of well-phenotyped subjects with integrated analysis of genomic, epigenomic, transcriptomic, proteomic and metabolomic data using interomic system biology approaches are required.

m6A RNA Methylation in Systemic Autoimmune Diseases-A New Target for Epigenetic-Based Therapy?

The general background of autoimmune diseases is a combination of genetic, epigenetic and environmental factors, that lead to defective immune reactions. This erroneous immune cell activation results in an excessive production of autoantibodies and prolonged inflammation. During recent years epigenetic mechanisms have been extensively studied as potential culprits of autoreactivity. Alike DNA and proteins, also RNA molecules are subjected to an extensive repertoire of chemical modifications. N6-methyladenosine is the most prevalent form of internal mRNA modification in eukaryotic cells and attracts increasing attention due to its contribution to human health and disease. Even though m6A is confirmed as an essential player in immune response, little is known about its role in autoimmunity. Only few data have been published up to date in the field of RNA methylome. Moreover, only selected autoimmune diseases have been studied in respect of m6A role in their pathogenesis. In this review, I attempt to present all available research data regarding m6A alterations in autoimmune disorders and appraise its role as a potential target for epigenetic-based therapies.

Immune responses and therapeutic options in psoriasis

Psoriasis is a chronic inflammatory disease of the skin that affects about 2-3% of the population and greatly impairs the quality of life of affected individuals. Psoriatic skin is characterized by excessive proliferation and aberrant differentiation of keratinocytes, as well as redness caused by increased dilation of the dermal blood vessels and infiltration of immune cells. Although the pathogenesis of psoriasis has not yet been completely elucidated, it is generally believed to arise from a complex interplay between hyperproliferating keratinocytes and infiltrating, activated immune cells. So far, the exact triggers that elicit this disease are still enigmatic, yet, it is clear that genetic predisposition significantly contributes to the development of psoriasis. In this review, we summarize current knowledge of important cellular and molecular mechanisms driving the initiation and amplification stages of psoriasis development, with a particular focus on cytokines and emerging evidence illustrating keratinocyte-intrinsic defects as key drivers of inflammation. We also discuss mouse models that have contributed to a better understanding of psoriasis pathogenesis and the preclinical development of novel therapeutics, including monoclonal antibodies against specific cytokines or cytokine receptors that have revolutionized the treatment of psoriasis. Future perspectives that may have the potential to push basic research and open up new avenues for therapeutic intervention are provided.

Paradoxical Psoriasis in Children Receiving Anti-TNFα Treatment for Inflammatory/autoimmune Disease

Tumor necrosis factor alpha inhibitors (TNFi) are widely used in children with autoimmune and autoinflammatory conditions. Although TNFi are approved to treat psoriasis, they have also been shown to paradoxically induce psoriasiform lesions. In this review, we aim to focus on the clinical presentation and management of paradoxical psoriasis after exposure to TNFi in children with juvenile idiopathic arthritis (JIA), inflammatory bowel disease (IBD), or chronic nonbacterial osteomyelitis (CNO). A narrative review of the literature was performed given the limited number of publications on this topic. Children with IBD, CNO, and JIA have a higher risk of developing psoriasis at baseline, which increases after TNFi use in those with JIA and IBD. Risk factors for paradoxical psoriasis remain incompletely defined, and patients with IBD and/or CNO develop paradoxical psoriasis more commonly than those with JIA. Sex, race, and family history were not significantly associated with paradoxical psoriasis. The most commonly implicated TNFi include infliximab and adalimumab. Paradoxical psoriasis occurs in a similar distribution on the body to isolated psoriatic lesions and is morphologically indistinguishable. In many instances, topical therapies are effective in treating psoriasis and children can continue on TNFi for their primary disease. If lesions are severe or unacceptable to patients, TNFi may be switched or discontinued. Further research is needed to better characterize risk factors and understand the mechanism of disease pathogenesis. Pediatric health care providers who prescribe TNFi should counsel families regarding the risk of paradoxical psoriasis prior to starting the medication and monitor for new cutaneous eruptions.

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.

Oxidative Stress and Lipid Mediators Modulate Immune Cell Functions in Autoimmune Diseases

Autoimmune diseases, including psoriasis, systemic lupus erythematosus (SLE), and rheumatic arthritis (RA), are caused by a combination of environmental and genetic factors that lead to overactivation of immune cells and chronic inflammation. Since oxidative stress is a common feature of these diseases, which activates leukocytes to intensify inflammation, antioxidants could reduce the severity of these diseases. In addition to activating leukocytes, oxidative stress increases the production of lipid mediators, notably of endocannabinoids and eicosanoids, which are products of enzymatic lipid metabolism that act through specific receptors. Because the anti-inflammatory CB2 receptors are the predominant cannabinoid receptors in leukocytes, endocannabinoids are believed to act as anti-inflammatory factors that regulate compensatory mechanisms in autoimmune diseases. While administration of eicosanoids in vitro leads to the differentiation of lymphocytes into T helper 2 (Th2) cells, eicosanoids are also necessary for the different0iation of Th1 and Th17 cells. Therefore, their antagonists and/or the genetic deletion of their receptors abolish inflammation in animal models of psoriasis—RA and SLE. On the other hand, products of non-enzymatic lipid peroxidation, especially acrolein and 4-hydroxynonenal-protein adducts, mostly generated by an oxidative burst of granulocytes, may enhance inflammation and even acting as autoantigens and extracellular signaling molecules in the vicious circle of autoimmune diseases.

Identification of protein/mRNA network involving the PSORS1 locus gene CCHCR1 and the PSORS4 locus gene HAX1

CCHCR1 (Coiled-Coil alpha-Helical Rod 1), maps to chromosomal region 6p21.3, within the major psoriasis susceptibility locus PSORS1. CCHCR1 itself is a plausible psoriasis candidate gene, however its role in psoriasis pathogenesis remains unclear. We previously demonstrated that CCHCR1 protein acts as a cytoplasmic docking site for RNA polymerase II core subunit 3 (RPB3) in cycling cells, suggesting a role for CCHCR1 in vesicular trafficking between cellular compartments. Here, we report a novel interaction between CCHCR1 and the RNA binding protein HAX1. HAX1 maps to chromosomal region 1q21.3 within the PSORS4 locus and is over-expressed in psoriasis. Both CCHCR1 and HAX1 share subcellular co-localization with mitochondria, nuclei and cytoplasmic vesicles as P-bodies. By a series of ribonucleoprotein immunoprecipitation (RIP) assays, we isolated a pool of mRNAs complexed with HAX1 and/or CCHCR1 proteins. Among the mRNAs complexed with both CCHCR1 and HAX1 proteins, there are Vimentin mRNA, previously described to be bound by HAX1, and CAMP/LL37 mRNA, whose gene product is over-expressed in psoriasis.

Skin Disease Models In Vitro and Inflammatory Mechanisms: Predictability for Drug Development

Investigative skin biology, analysis of human skin diseases, and numerous clinical and pharmaceutical applications rely on skin models characterized by reproducibility and predictability. Traditionally, such models include animal models, mainly rodents, and cellular models. While animal models are highly useful in many studies, they are being replaced by human cellular models in more and more approaches amid recent technological development due to ethical considerations. The culture of keratinocytes and fibroblasts has been used in cell biology for many years. However, only the development of co-culture and three-dimensional epidermis and full-skin models have fundamentally contributed to our understanding of cell-cell interaction and cell signalling in the skin, keratinocyte adhesion and differentiation, and mechanisms of skin barrier function. The modelling of skin diseases has highlighted properties of the skin important for its integrity and cutaneous development. Examples of monogenic as well as complex diseases including atopic dermatitis and psoriasis have demonstrated the role of skin models to identify pathomechanisms and drug targets. Recent investigations have indicated that 3D skin models are well suitable for drug testing and preclinical studies of topical therapies. The analysis of skin diseases has recognized the importance of inflammatory mechanisms and immune responses and thus other cell types such as dendritic cells and T cells in the skin. Current developments include the production of more complete skin models comprising a range of different cell types. Organ models and even multi-organ systems are being developed for the analysis of higher levels of cellular interaction and drug responses and are among the most recent innovations in skin modelling. They promise improved robustness and flexibility and aim at a body-on-a-chip solution for comprehensive pharmaceutical in vitro studies.

The Role of Leptin in the Association between Obesity and Psoriasis

Adipose tissue secretes many adipokines which contribute to various metabolic processes, such as blood pressure, glucose homeostasis, inflammation and angiogenesis. The biology of adipose tissue in an obese individual is abnormally altered in a manner that increases the body’s vulnerability to immune diseases, such as psoriasis. Psoriasis is considered a chronic inflammatory skin disease which is closely associated with being overweight and obese. Additionally, secretion of leptin, a type of adipokine, increases dependently on adipose cell size and adipose accumulation. Likewise, high leptin levels also aggravate obesity via development of leptin resistance, suggesting that leptin and obesity are closely related. Leptin induction in psoriatic patients is mainly driven by the interleukin (IL)-23/helper T (Th) 17 axis pathway. Furthermore, leptin can have an effect on various types of immune cells such as T cells and dendritic cells. Here, we discuss the relationship between obesity and leptin expression as well as the linkage between effect of leptin on immune cells and psoriasis progression.

Attitudes Towards Appearance and Body-Related Stigma Among Young Women With Obesity and Psoriasis

The goal of this study was to investigate the role of the subjective assessment of one's body image in the relationship between objective indices of appearance and perceived stigma in young women affected by obesity and psoriasis. These are chronic diseases that decrease one's physical attractiveness and are associated with stigmas related to body defects. A total of 188 women in early adulthood took part in the study (M = 25.58; SD = 2.90), including obese women (n = 54), women suffering from psoriasis (n = 57), and a control group (n = 77). The participants completed the Multidimensional Body-Self Relations Questionnaire, Perceived Stigmatisation Questionnaire, and a socio-demographic questionnaire. Anthropometric data were gathered using a body composition analyzer. Objective parameters of body shape were calculated (WHR and ICO). Subjective assessment of one's body and attitudes towards one's body were found to influence perceived stigma, independently of the condition causing the stigma and of the objective appearance of the participant. This study did not support the existence of a relationship between parameters regarding body shape and sense of stigma, even when subjective body assessment acted as a moderator. At the same time, body mass was a strong predictor of levels of perceived stigma. Women affected with obesity perceived a higher level of stigma than the other groups. The severity of psoriasis did not impact the perceived stigma. Moreover, women with psoriasis assessed their health-as a part of the assessment of their bodies-the highest, which may explain the lower perceived stigma in this group.

Two Variants in the NOTCH4 and HLA-C Genes Contribute to Familial Clustering of Psoriasis

Psoriasis is a multifactorial immune-mediated skin disease with a strong genetic background. Previous studies reported that psoriasis with a family history (PFH) and sporadic psoriasis (SP) have a distinct manifestation and genetic predisposition. However, the genetic heterogeneity of PFH and SP in the major histocompatibility complex (MHC) region has not been fully elucidated. To explore genetic variants in the MHC region that drive family aggregation of psoriasis, we included a total of 8,127 psoriasis cases and 9,906 healthy controls from Han Chinese and divided psoriasis into two subtypes, PFH (n = 1,538) and SP (n = 5,262). Then, we calculated the heritability of PFH and SP and performed a large-scale stratified association analysis. We confirmed that variants in the MHC region collectively explained a higher heritability of PFH (16.8%) than SP (13.3%). Further stratified association analysis illustrated that HLA-C∗06:02 and NOTCH4:G511S contribute to the family aggregation of psoriasis, and BTNL2:R281K specifically confers risk for SP. HLA-C∗06:02 and NOTCH4:G511S could partially explain why patients with PFH have a stronger genetic predisposition, more complex phenotypes, and more frequent other autoimmune diseases. The identification of the SP-specific variant BTNL2:R281K revealed that the genetic architecture of SP is not just a subset of PFH.