The Clinical Genetics of Psoriasis

Functional significance of the rare rs35667974 IFIH1 gene polymorphism, associated with multiple autoimmune diseases, using a structural biological approach

Autoimmune diseases, which affect approximately 5% of human population, are a range of diseases in which the immune response to self-antigens results in damage or dysfunction of tissues. Recent genome wide association studies (GWAS) have successfully identified novel autoimmune disease-associated loci, with many of them shared by multiple disease-associated pathways but much of the genetics and pathophysiological mechanisms remain still obscure. Considering that most of the potential causal variants are still unknown, many studies showed that the missense variant rs35667974 at interferon-induced with helicase C domain 1 (IFIH1) gene is protective for type 1 diabetes (T1D), psoriasis (PS) and psoriatic arthritis (PsA). Recently, this variant was found to be also associated with ankylosing spondylitis (AS), Crohn's disease (CD) and ulcerative colitis (UC). The IFIH1 gene encodes a cytoplasmic RNA helicase otherwise known as melanoma differentiation-associated 5 (MDA5) that recognizes viral RNA and is involved in innate immunity through recognition of viral RNA. In the present study we sought to investigate the association of the rare rs35667974 variant of IFIH1 gene, which resides in exon 14 and changes a conserved isoleucine at position #923 to valine, in the development of various autoimmune diseases and give a reason for the selectivity affecting different autoimmune diseases. Evolutionary studies and three-dimensional (3 D) homology modelling were employed on the MDA5 protein product, through its association with dsRNA, recognition factor controlling cytokine and chemokine signalling, to investigate the protective role of the MDA5 variant for certain autoimmune diseases.

Assessment of the Effect of Metabolic Syndrome on the Autophagy Marker LC3 in Psoriasis Vulgaris Patients: A Cross-Sectional Study

Purpose

Psoriasis vulgaris, one of the most prevalent chronic inflammatory skin diseases, is associated with metabolic syndrome (MetS). Autophagy, an intracellular degradation system is essential for cell survival and differentiation, and its dysfunction may contribute to metabolic diseases. A cross-sectional study was conducted on 38 psoriasis vulgaris patients and 16 healthy control subjects to 1) Assess immunohistochemical (IHC) expression of microtubule-associated protein light chain 3 (LC3); 2) Evaluate the relationship between Psoriasis Area Severity Index (PASI) score, and LC3 expression.

Patients and Methods

PASI score was evaluated for all psoriasis patients. Lipid profile, blood sugar, and CRP were done for all patients and controls. A punch biopsy was taken from lesional and perilesional skin of psoriasis patients and normal skin of the controls. Tissue sections were prepared. IHC LC3 staining was done and evaluated.

Results

LC3 was nearly absent, in the epidermis of the lesional skin of psoriasis while it was strong among control (p=0.001). LC3 expression in the lesional skin of psoriasis vulgaris was lower than its expression in perilesional (p=0.001). However, LC3 expression was not significantly changed with PASI or the presence/absence of MetS.

Conclusion

A potential link between psoriasis vulgaris and autophagy as assessed by LC3 could be present. LC3 was down-regulated in psoriasis lesions than in normal skin. However, its expression did not change with PASI or MetS. An autophagy enhancer might be used as a possible therapeutic target in psoriasis vulgaris patients.

Autophagy in Skin Diseases

Autophagy, or self-eating, is an evolutionarily conserved process in which cytosol and organelles are sequestered within double-membrane vesicles that deliver the contents to the lysosome/vacuole for the degradation and recycling of cytoplasmic components in eukaryotes. It is well recognized that autophagy plays an important role in maintaining cellular homeostasis under physiological and pathophysiological con-ditions and the upregulation of autophagy may serve as an adaptive process to provide nutrients and energy when under stresses. Recently, studies have illustrated that autophagy is intricately related to skin diseases. This review provides a brief synopsis of the process of autophagy and aims to elucidate the roles of autophagy in different skin diseases and to highlight the need for increased research in the field.

Molecular Phenotyping Small (Asian) versus Large (Western) Plaque Psoriasis Shows Common Activation of IL-17 Pathway Genes but Different Regulatory Gene Sets

Psoriasis is present in all racial groups, but in varying frequencies and severity. Considering that small plaque psoriasis is specific to the Asian population and severe psoriasis is more predominant in the Western population, we defined Asian small and intermediate plaque psoriasis as psoriasis subtypes, and compared their molecular signatures with classic subtype of Western large plaque psoriasis. Two different characteristics of psoriatic spreading—vertical growth and radial expansion—were contrasted between subtypes, and genomic data were correlated to histologic and clinical measurements. Compared to Western large plaque psoriasis, Asian small plaque psoriasis revealed limited psoriasis spreading, but IL-17A and IL-17-regulated pro-inflammatory cytokines were highly expressed. Paradoxically, IL-17A and IL-17-regulated pro-inflammatory cytokines were lower in Western large plaque psoriasis, while T cells and dendritic cells in total psoriatic skin area were exponentially increased. Negative immune regulators, such as CD69 and FAS, were decreased in both Western large plaque psoriasis and psoriasis with accompanying arthritis or obesity, and their expression was correlated with psoriasis severity index. Based on the disease subtype comparisons, we propose that dysregulation of T cell expansion enabled by downregulation of immune negative regulators is the main mechanism for development of large plaque psoriasis subtypes.

Retinoic acid and hydroquinone induce inverse expression patterns on cornified envelope-associated proteins: implication in skin irritation

BACKGROUND

Hydroquinone (HQ) with or without retinoic acid (RA) is routinely used for the treatment of hyperpigmented conditions. Skin irritation is a major problem with popular depigmenting agents, resulting in postinflammatory hyperpigmentation.

OBJECTIVE

To examine the molecular mechanism associated with skin irritation by RA or HQ.

METHODS

A genome-wide transcriptional profiling analysis was performed using monolayer cultures of human keratinocytes treated with or without irritant doses of RA, HQ, or sodium lauryl sulfate (SLS), a representative irritant. Differentially expressed genes (DEGs) were mapped on human chromosomes using a Manhattan plot. For the validation of candidate DEGs, the chemicals with different concentrations of varying irritation intensities were applied in vitro and in vivo and analyzed using real time-PCR and Western blotting.

RESULTS

DEGs mapped to the 1q21 locus, which is composed of a cluster of genes encoding the cornified envelope precursors, showed an inverse expression pattern in response to HQ and RA. Concentrations of RA and HQ that induced a broad range of irritant responses in cultured cells or mice skin also induced inverse effects on the expression of cornified envelope-associated proteins.

CONCLUSIONS

Genetic modulation on cornified envelope-associated proteins by RA-induced irritation, which may be involved in physiological skin barrier disturbance, could be inverse to that by HQ- or SLS-induced irritation.

Psoriasis, a new challenge for laboratory medicine

Psoriasis is an immune-mediated, chronic, inflammatory disease that affects the skin and joints. Because of its high incidence and of its clinical symptoms it has a very strong social impact. In a genetically predisposed individual, the maintenance of the skin barrier integrity is strongly compromised in response to either environmental or self-antigenic insults. A persistent dysregulation of the skin immune system causes the typical evolutive skin lesions of psoriasis and recurrence of the disease. The most efficient laboratory approach consists of a well-defined evaluation of immune response in order to help diagnosis, to monitor evolution, and to evaluate the effects of individualized therapeutic treatments.

Hyperbranched dendritic nano-carriers for topical delivery of dithranol

The purpose of the current investigation was to explore the potential of polypropylene imine (PPI) dendrimers to deliver dithranol (DIT) topically and to evaluate its encapsulation, permeation and skin irritation potential. PPI (5.0 generation, 5.0 G) dendrimers and DIT-loaded PPI (DIT-PPI) were prepared and characterized by spectroscopy and transmission electron microscopy. DIT encapsulation, in vitro skin permeation study, skin irritation studies, fluorescent studies and tape stripping studies were performed. Loading of DIT was found to be pH dependent with maximum encapsulation at acidic pH (1.0 ± 0.02, 17.2 ± 0.56 and 57.1 ± 1.32% at 7.4, 5.5 and 1.2 pH, respectively). DIT-PPI showed significantly enhanced permeation rate constant and lesser skin irritation (11.61 ± 1.80 μg/cm(2)/h and 1.0, respectively) when compared with the plain DIT solution (2.72 ± 0.31 μg/cm(2)/h and 2.3, respectively). Skin separation studies and confocal laser scanning microscope images showed that the dye-loaded dendrimers exhibits deposition of dye in pilosebaceous compartment. These studies demonstrate that PPI can be exploited to improve the topical bioavailability of the molecules in a controlled pattern. The enhanced accumulation of DIT via dendrimer carrier within the skin might help optimize targeting of this drug to the epidermal and dermal sites, thus creating new opportunities for well-controlled, modern topical application of DIT for the treatment of psoriasis.

Analysis of genetic variants of class II cytokine and their receptor genes in psoriasis patients of two ethnic groups from the Volga-Ural region of Russia

BACKGROUND

The molecular basis of pathogenesis of psoriasis remains unclear, but one unifying hypothesis of disease aetiology is the cytokine network model. The class II cytokines (CF2) and their receptors (CRF2) are all involved in the inflammatory processes and single nucleotide polymorphisms (SNPs) in respective genes have been associated with psoriasis in a previous study of the Estonian population.

OBJECTIVE

We performed a replication study of 47 SNPs in CF2 and CRF2 genes in independent cohorts of psoriasis patients of two ethnic groups (Russians and Bashkirs) from the Volga-Ural region of Russia.

METHODS

DNA was obtained from 395 psoriasis patients of two ethnic groups from the Volga-Ural region of Russia and 476 ethnically matched controls. 47 SNPs in the loci of the genes encoding Class II cytokines and their receptors were selected by SNPbrowser version 3.5. Genotyping was performed using the SNPlex™ (Applied Biosystems) platform.

RESULTS

The genetic variant rs30461 previously associated in original case-control study in Estonians, was also associated in Russians (corrected P-value (Pc=0.008, OR=0.44), but did not reach statistical significance in the Bashkir population. Additionally, the haplotype analysis provided that CC haplotype formed by the SNPs rs30461 and rs955155 had a protective effect in Russians (Pc=0.0024, OR=0.44), supporting the involvement of this locus in the protection against psoriasis. Combined meta-analysis of three populations, including 943 psoriasis patients and 812 healthy controls, showed that the IL29 rs30461 C-allele was not associated with decreased risk of psoriasis (P=0.165, OR=0.68). Moreover, stratification of studies by ethnicity revealed a significant association in the European cohort (P=9.506E-006, OR=0.53).

CONCLUSION

Therefore, there is no overall evidence of association between psoriasis and SNP rs30461 of the IL29 gene, but there is some evidence to suggest that an association exists in Europeans. However, this current concept should be considered as preliminary and the results need to be confirmed in future independent studies.

Markers of efficacy of Infliximab in psoriasis patients

The article presents the results of molecular and genetic studies aimed at determination of molecular markers for forecasting the clinical response of psoriasis patients to treatment with Infliximab. The authors revealed that it is possible to forecast high efficacy of treatment with Infliximab in case TT genotype is revealed at the 676 locus of exon 6 of the TNF-RII gene and IL-10 is present in the blood serum prior to the onset of treatment in the amount of more than 2.7 pg/ml.

A CD40 and an NCOA5 gene polymorphism confer susceptibility to psoriasis in a Southern European population: a case-control study

Recent genome-wide association studies of many complex diseases have successfully identified novel susceptibility loci, with many of them shared by multiple disease-associated pathways. The genes CD40 and nuclear receptor coactivator 5 (NCOA5), located in a 400-kb region surrounding CD40, have been reported to be associated with increased risk for rheumatoid arthritis and other autoimmune diseases. We hypothesized that those genes may also have a role in psoriasis (PS), an autoimmune, chronic inflammatory skin disease. In a case-control study, 198 patients with PS and 400 controls were genotyped for 2 single nucleotide polymorphisms (SNPs) of the CD40 and NCOA5 genes located on chromosome 20q.12-q13.12. Here, we demonstrate for the first time the association of both SNPs with susceptibility to PS, thus suggesting a putative key role of both genes in multiple autoimmune diseases. Alleles G and C of the CD40 rs4810485 and NCOA5 rs2903908 SNPs, respectively, were more common in individuals with PS than in controls (p = 0.03, odds ratio [OR] = 1.42, 95% confidence interval [95% CI] 1.05-1.95 and p = 0.000 003, OR = 1.93, 95% CI 1.47-2.55, respectively). The identification of shared genetic susceptibility loci may provide insight into our understanding of the pathophysiology of autoimmune diseases.

Topical delivery for the treatment of psoriasis

IMPORTANCE OF THE FIELD

Psoriasis is one of the most common human skin diseases. Topical therapy forms the cornerstone in the management of mild-to-moderate psoriasis. Topical therapies are also used as adjunctive to systemic therapy in moderate and severe forms of the disease.

AREAS COVERED IN THIS REVIEW

In this review, an overview of psoriasis pathogenesis, new topical medications for psoriasis, new targets and molecules, combination topical therapies and combination of topical and phototherapy is provided. Over the past decade several efficacious and acceptable treatment options have emerged from the age-old therapies. The development of sophisticated formulation options has led to an enhancement in the rate and extent of drug delivery across the skin, increasing therapeutic value and improving patient compliance.

WHAT THE READER WILL GAIN

Readers will learn about monotherapy and combination topical products as well as new topical drug delivery technology to achieve optimal clinical outcomes. This review will highlight the need to generate more dermal pharmacokinetic data for better understanding of the impact of formulation change on skin pharmacokinetics to help design improved topical drug delivery systems.

TAKE HOME MESSAGE

New topical formulations have the potential to achieve better efficacy with improved safety profile.

Carriers of rare missense variants in IFIH1 are protected from psoriasis

Testing of ∼25,000 putative functional single-nucleotide polymorphisms (SNPs) across the human genome in a genetic association study has identified three psoriasis genes, IL12B, IL23R, and IL13. We now report evidence for the association of psoriasis risk with missense SNPs in the interferon induced with helicase C domain 1 gene (IFIH1). The rare alleles of two independent SNPs were associated with decreased risk of psoriasis--rs35667974 (Ile923Val): odds ratio (OR) for minor allele carriers is 0.43, P=2.36 × 10(-5) (2,098 cases vs. 1,748 controls); and rs10930046 (His460Arg): OR for minor allele carriers is 0.51, P=6.47 × 10(-4) (2,098 cases vs. 1,744 controls). Compared to noncarriers, carriers of the 923Val and/or 460Arg variants were protected from psoriasis (OR=0.46, P=5.56 × 10(-8)). To our knowledge, these results suggest that IFIH1 is a previously unreported psoriasis gene.

The protein tyrosine phosphatase, non-receptor type 22 R620W polymorphism does not confer susceptibility to psoriasis in the genetic homogeneous population of Crete

Recent whole-genome and candidate-gene association studies in patients with psoriasis (PS) have identified a number of single-nucleotide polymorphisms (SNPs) that predispose to disease with moderate risk. Predisposition to PS is known to be affected by genetic variation in human leukocyte antigen-C as well as other non-human leukocyte antigen genes. We recently reported for the first time as a PS-associated SNP the signal transducer and activator of transcription-4 (STAT4) rs7574865 polymorphism, which is also associated with several autoimmune diseases. The aim of this study was to assess whether the functional R620W polymorphism of protein tyrosine phosphatase, non-receptor type 22 (PTPN22) gene encoding the lymphoid-specific tyrosine phosphatase, which is known to be associated with various autoimmune diseases, also confers increased risk for PS in the genetic homogeneous population of Crete. A case-control study was performed with 173 PS patients consecutively recruited and 348 healthy controls, all of them from the island of Crete. We found that the mutated T allele of the PTPN22 1858T SNP was more common in control individuals than in patients with PS (odds ratio = 0.39, 95% confidence interval = 0.11-1.04, p = 0.09). No considerable difference was observed in terms of sex, age of onset, or clinical presentation of psoriatic arthritis. Our results provide evidence that the PTPN22 1858T allele is not a susceptibility factor for PS in the Cretan population.

Molecular Markers In Forecasting The Clinical Efficacy Of Infliximab In Psoriasis Patients

Biosamples (skin tissue samples taken from affection foci and blood serum) from 22 patients suffering from severe to medium psoriasis (8 women and 14 men) aged 19-57 treated with Infliximab were analyzed. As for skin tissue samples, the molecular structure of genes TNF-a, TNF-R-I and TNF-R-II, contents of cytokine TNF-a and its soluble receptors (sTNF-RI and sTNF-RII) and proteome composition was analyzed in skin tissue samples; contents of TNF-a, IL2, IL4, IL6, IL-8 and IL-10 were analyzed in the blood serum. The homozygous TT genotype of TNF-R-II gene at the 676 locus and high IL10 level in the blood serum (>2.7 pg/ml) was associated with the high intensity of the psoriasis patient response to treatment with Infliximab; the homozygous GG genotype of TNF-R-II gene at the 676 locus and low level of IL10 in the blood serum (

Immunomorphology and Morphogenesis of Affected Skin Foci at Psoriasis

The article provides information about the pathogenic role of different immunocompetent cells in forming an immune inflammation in the skin of psoriasis patients, which is one of the most important factors in the development of psoriatic eruptions in case of exacerbation of the disease. The contents of CD4+ helper lymphocytes, CD8+ suppressor/cytotoxic lymphocytes, CD1a+ Langerhans cells and HLA-DR+ cells in the affected skin in psoriasis patients were analyzed. It was revealed that the development of an immune inflammation in the skin of psoriasis patients involves cells of congenital (CD1a+ Langerhans cells) and adaptive immunity (CD4+ and CD8+ Т lymphocytes), and their number grows.

Patented small molecules against psoriasis

BACKGROUND

It is hypothesized that psoriasis is an autoimmune disease. The most recent therapeutic approach that proved to be more effective than earlier methods of treatment is the use of mAb/fusion proteins. Efforts nowadays are focused on investigating the antipsoriatic affect of small molecules that can be administered orally, some of which are capable of entering cells, and being selective in targeting intracellular pathways.

OBJECTIVE

Preclinical patented small molecules that are recommended for the treatment of psoriasis are reviewed. Emphasis is placed on their mechanism of action.

METHODS

http://ep.espacenet.com/ , Pubmed, Scopus and Google websites were the main sources used for the patented small molecule search. A number of patents were poorly described and difficulties were faced in trying to figure out the patentee(s) explanation. Moreover, most patents were recommended for the treatment of a number of autoimmune diseases and cancer, and not only for psoriasis.

RESULTS/CONCLUSIONS

Small molecules that inhibit the activation of T lymphocytes, leukocyte trafficking, leukotriene activity/production and angiogenesis, and promote apoptosis have been patented. Small molecules that have been patented for the treatment of other autoimmune diseases and could be used for treating psoriasis are described. Moreover, other possible mechanistic approaches using small molecules are discussed.

Association of the CTG (-2578/-460/+405) haplotype within the vascular endothelial growth factor gene with early-onset psoriasis

Polymorphism of vascular endothelial growth factor (VEGF) influences the VEGF production and is subjected to genetic susceptibility of many diseases including psoriasis. Three single nucleotide polymorphisms (SNPs) within the promoter and exon 1 region [-2578(C/A), -460(C/T) and +405(C/G)] were analyzed in 154 patients with chronic plaque psoriasis and in 234 ethnically matched healthy controls from Thailand. The CTG (-2578/-460/+405) haplotype frequency was higher in patients with early-onset psoriasis (44.12%) compared with healthy controls (33.33%) (odds ratio = 1.54, 95% confidence interval = 1.08-2.18, P = 0.016, corrected P value: P(c) = 0.048). The results suggest that the CTG haplotype can be used as a genetic marker for psoriasis especially the early-onset group of Thais.

STAT4 gene polymorphism is associated with psoriasis in the genetically homogeneous population of Crete, Greece

Recent genome-wide association studies (GWAS) of many complex diseases have successfully identified novel susceptibility loci, with many of them being associated with more than one condition. Taking into consideration that different autoimmune diseases may share some common pathogenetic pathways, we hypothesized that STAT4, a susceptibility gene found to be associated with increased risk for systemic lupus erythematosus, rheumatoid arthritis, type 1 diabetes, Sjögren's syndrome, Wegener's granulomatosis, Crohn's disease, and ulcerative colitis may also have a role in psoriasis. Psoriasis is an autoimmune, chronic inflammatory skin disease. Here we performed a case-control study in the population of island of Crete and demonstrated for the first time the association of a STAT4 single nucleotide polymorphism (SNP) with susceptibility to psoriasis, thus suggesting a putative key role of STAT4 in multiple autoimmune diseases. We found that mutated allele T of the STAT4 rs7574865 SNP, which previously was implicated in the predisposition to many autoimmune diseases, were more common in individuals with psoriasis than in controls (p = 0.045, odds ratio = 1.42, 95% confidence interval 1.01-2.00), thus concluding that the polymorphism examined is associated with the development of psoriasis in our population.

Further genetic evidence for three psoriasis-risk genes: ADAM33, CDKAL1, and PTPN22

Predisposition to psoriasis is known to be affected by genetic variation in HLA-C, IL12B, and IL23R, and although other psoriasis-associated variants have been identified, incontrovertible statistical evidence for these markers has not yet been obtained. To help resolve this issue, we tested 15 single-nucleotide polymorphisms (SNPs) from 7 putative psoriasis-risk genes in 1,448 psoriasis patients and 1,385 control subjects; 3 SNPs, rs597980 in ADAM33, rs6908425 in CDKAL1 and rs3789604 in PTPN22, were significant with the same risk allele as in prior reports (one-sided P<0.05, false discovery rate<0.15). These three markers were tested in a fourth sample set (599 cases and 299 controls); one marker, rs597980, replicated (one-sided P<0.05) and the other two had odds ratios with the same directionality as in the original sample sets. Mantel-Haenszel meta-analyses of all available case-control data, including those published by other groups, showed that these three markers were highly significant (rs597980: P=0.0057 (2,025 cases and 1,597 controls), rs6908425: P=1.57 x 10(-5) (3,206 cases and 4,529 controls), and rs3789604: P=3.45 x 10(-5) (2,823 cases and 4,066 controls)). These data increase the likelihood that ADAM33, CDKAL1, and PTPN22 are true psoriasis-risk genes.