Identifying the genetic associations among the psoriasis patients in eastern India.

Psoriasis is a multifactorial genetic disorder manifested by hyperproliferation and abnormal differentiation of epidermal keratinocytes, along with the infiltration of inflammatory cells into the skin. Although ~80 genetic susceptibility variants were reported in psoriasis, many loci showed population-specific associations, warranting the need for more population-specific association studies in psoriasis. We determined the association of forty single nucleotide polymorphisms (SNPs) among 2136 psoriasis patients and normal individuals from eastern India. We investigated the expression of corresponding genes and evaluated the protein structure stability for the genes with susceptible coding variants. We found fifteen SNPs significantly associated with psoriasis, while additional three SNPs showed significant association when we classified the patients based on the presence of HLA-Cw6 allele. Epistatic interaction between HLA-Cw6 and other associated loci showed significant association with the SNPs at PSORS1 region, along with other five SNPs outside PSORS1. Three genes showed significant differential expression in psoriatic tissues compared to the adjacent normal skin tissues but were not differential when classified the patients based on their genotypes. SNP rs495337 at SPATA2 (Spermatogenesis Associated 2) showed a 1.2-fold increased risk among the HLA-Cw6 patients compared to combined samples. We found significant downregulation of SPATA2 among the patients with risk genotypes and HLA-Cw6 allele compared to the non-risk genotypes. Protein structure stability analysis showed reduced structural stability for all the mutant residues caused by the associated coding variants. Our study evaluated the genetic associations of psoriasis-susceptible variants in India and evaluated the possible functional significance of these associated variants in psoriasis.

Serum miRNA profiling identified miRNAs associated with disease severity in psoriasis.

Psoriasis vulgaris is a chronic, autoimmune skin disease involving a complex interplay of epidermal keratinocytes, dermal fibroblast and infiltrating immune cells. Differential expressions of miRNAs are observed in psoriasis and the deregulated miRNAs are sometimes associated with disease severity. This study aims to identify miRNAs altered in the serum of psoriasis patients that are associated with the Psoriasis Area and Severity Index (PASI). In order to assess miRNA levels in the serum of psoriasis patients, we selected 24 differentially expressed miRNAs in the psoriatic skin are possibly derived from the skin and immune cells, as well as five miRNAs that are enriched in other tissues. We identified 16 miRNAs that exhibited significantly (p < 0.05) altered levels in the serum of psoriasis patients compared to healthy individuals. Among these, 13 miRNAs showed similar expression pattern in the serum of psoriasis patients as also observed in the psoriatic skin tissues. Ten miRNAs showed an accuracy of greater than 75% in classifying the psoriasis patients from healthy individuals. Further analysis of differential miRNA levels between the low PASI group and the high PASI group identified three miRNAs (miR-147b, miR-3614-5p, and miR-125a-5p) with significantly altered levels between the low severity and the high severity psoriasis patients. Our systematic investigation of skin and immune cell-derived miRNAs in the serum of psoriasis patients revealed alteration in miRNA levels to be associated with disease severity, which may help in monitoring the disease progression and therapeutic response.

MICaps: Multi-instance capsule network for machine inspection of Munro's microabscess.

Munro's Microabscess (MM) is the diagnostic hallmark of psoriasis. Neutrophil detection in the Stratum Corneum (SC) of the skin epidermis is an integral part of MM detection in skin biopsy. The microscopic inspection of skin biopsy is a tedious task and staining variations in skin histopathology often hinder human performance to differentiate neutrophils from skin keratinocytes. Motivated from this, we propose a computational framework that can assist human experts and reduce potential errors in diagnosis. The framework first segments the SC layer, and multiple patches are sampled from the segmented regions which are classified to detect neutrophils. Both UNet and CapsNet are used for segmentation and classification. Experiments show that of the two choices, CapsNet, owing to its robustness towards better hierarchical object representation and localisation ability, appears as a better candidate for both segmentation and classification tasks and hence, we termed our framework as MICaps. The training algorithm explores both minimisation of Dice Loss and Focal Loss and makes a comparative study between the two. The proposed framework is validated with our in-house dataset consisting of 290 skin biopsy images. Two different experiments are considered. Under the first protocol, only 3-fold cross-validation is done to directly compare the current results with the state-of-the-art ones. Next, the performance of the system on a held-out data set is reported. The experimental results show that MICaps improves the state-of-the-art diagnosis performance by 3.27% (maximum) and reduces the number of model parameters by 50%.

Functional Mapping of Genetic Interactions between HLA-Cw6 and LCE3A in Psoriasis.

Functional studies to delineate the molecular mechanisms of causal genetic variants are the main focus in the post-GWAS era. Previous GWASs have identified >50 susceptibility loci associated with psoriasis. Functional understanding of the biology underlying the disease risk of most of these associated loci is unclear. In this study, we identified a regulatory SNP at the putative enhancer of the LCE3A gene within the epidermal differentiation complex that showed epistatic interaction with HLA-Cw6. The variant allele disrupted signal transducer and activator of transcription 3 binding to the region, thereby regulating the expression of the downstream LCE3A gene. Electrophoretic mobility shift and pulldown assay confirmed the preferential binding of signal transducer and activator of transcription 3 to the DNA with a wild-type allele compared with the DNA with a variant allele. The reporter assay further validated the IL-6‒stimulated phosphorylated signal transducer and activator of transcription 3‒mediated LCE3A activation in the presence of the wild-type allele. Interestingly, the presence of the HLA-Cw6 allele leads to IL-6‒mediated phosphorylation of signal transducer and activator of transcription 3, followed by its nuclear localization in the epidermal keratinocytes of psoriatic skin, suggesting indirect interaction of the HLA-Cw6 allele and a regulatory SNP upstream of the LCE3A gene. This study reflects an interesting approach to dissecting the molecular mechanism underlying the genetic interaction observed between HLA-Cw6 and LCE3A in psoriasis pathogenesis.

Epigenome-wide DNA methylation regulates cardinal pathological features of psoriasis.

BACKGROUND: Psoriasis is a chronic inflammatory autoimmune skin disorder. Several studies suggested psoriasis to be a complex multifactorial disease, but the exact triggering factor is yet to be determined. Evidences suggest that in addition to genetic factors, epigenetic reprogramming is also involved in psoriasis development. Major histopathological features, like increased proliferation and abnormal differentiation of keratinocytes, and immune cell infiltrations are characteristic marks of psoriatic skin lesions. Following therapy, histopathological features as well as aberrant DNA methylation reversed to normal levels. To understand the role of DNA methylation in regulating these crucial histopathologic features, we investigated the genome-wide DNA methylation profile of psoriasis patients with different histopathological features. RESULTS: Genome-wide DNA methylation profiling of psoriatic and adjacent normal skin tissues identified several novel differentially methylated regions associated with psoriasis. Differentially methylated CpGs were significantly enriched in several psoriasis susceptibility (PSORS) regions and epigenetically regulated the expression of key pathogenic genes, even with low-CpG promoters. Top differentially methylated genes overlapped with PSORS regions including S100A9, SELENBP1, CARD14, KAZN and PTPN22 showed inverse correlation between methylation and gene expression. We identified differentially methylated genes associated with characteristic histopathological features in psoriasis. Psoriatic skin with Munro's microabscess, a distinctive feature in psoriasis including parakeratosis and neutrophil accumulation at the stratum corneum, was enriched with differentially methylated genes involved in neutrophil chemotaxis. Rete peg elongation and focal hypergranulosis were also associated with epigenetically regulated genes, supporting the reversible nature of these characteristic features during remission and relapse of the lesions. CONCLUSION: Our study, for the first time, indicated the possible involvement of DNA methylation in regulating the cardinal pathophysiological features in psoriasis. Common genes involved in regulation of these pathologies may be used to develop drugs for better clinical management of psoriasis.

Psoriasis skin biopsy image segmentation using Deep Convolutional Neural Network.

BACKGROUND AND OBJECTIVE: Development of machine assisted tools for automatic analysis of psoriasis skin biopsy image plays an important role in clinical assistance. Development of automatic approach for accurate segmentation of psoriasis skin biopsy image is the initial prerequisite for developing such system. However, the complex cellular structure, presence of imaging artifacts, uneven staining variation make the task challenging. This paper presents a pioneering attempt for automatic segmentation of psoriasis skin biopsy images. METHODS: Several deep neural architectures are tried for segmenting psoriasis skin biopsy images. Deep models are used for classifying the super-pixels generated by Simple Linear Iterative Clustering (SLIC) and the segmentation performance of these architectures is compared with the traditional hand-crafted feature based classifiers built on popularly used classifiers like K-Nearest Neighbor (KNN), Support Vector Machine (SVM) and Random Forest (RF). A U-shaped Fully Convolutional Neural Network (FCN) is also used in an end to end learning fashion where input is the original color image and the output is the segmentation class map for the skin layers. RESULTS: An annotated real psoriasis skin biopsy image data set of ninety (90) images is developed and used for this research. The segmentation performance is evaluated with two metrics namely, Jaccard's Coefficient (JC) and the Ratio of Correct Pixel Classification (RCPC) accuracy. The experimental results show that the CNN based approaches outperform the traditional hand-crafted feature based classification approaches. CONCLUSIONS: The present research shows that practical system can be developed for machine assisted analysis of psoriasis disease.

Associations of ERAP1 coding variants and domain specific interaction with HLA-C∗06 in the early onset psoriasis patients of India.

Interferon-γ-induced aminopeptidase ERAP1 trims peptides within the endoplasmic reticulum so that they can be loaded onto MHC class I and presented to the CD8+ T-cells. ERAP1 association and its interaction with HLA-C∗06 is controversial across different populations. We have investigated the association and possible functional role of non-synonymous SNPs at different exons of ERAP1 (rs26653: Arg127Pro, rs30187: Lys528Arg and rs27044: Gln730Glu) and their interactions with HLA-C∗06 in psoriasis. Significant associations of HLA-C∗06 (OR=5.47, P<2.2×10-16), rs30187 (OR 1.35, P=7.4×10-4) and rs27044 (OR=1.24, P=5.8×10-3) were observed. All three ERAP1 SNPs showed significant association only for HLA-C∗06 positive patients, while rs30187 and rs27044 showed significant association only for early onset patients (rs30187: OR=1.47, P=9.6×10-5; rs27044: OR=1.36, P=3.3×10-4). No differential expression of ERAP1 was observed either between paired uninvolved and involved skin tissues of psoriasis patients or between non-risk and risk variants in the involved skin. Significant epistatic interaction was observed between HLA-C∗06 and the SNP (rs27044) located at the peptide-binding cavity of ERAP1. Evolutionary conservation analysis among mammals showed confinement of Lys528 and Gln730 within highly conserved regions of ERAP1 and suggested the possible detrimental effect of this allele in ERAP1 regulation.

Association of IL12B risk haplotype and lack of interaction with HLA-Cw6 among the psoriasis patients in India.

Psoriasis is a complex multifactorial chronic inflammatory skin disorder involving both genetic and environmental susceptibility factors. It is strongly associated with HLA-Cw6, but several studies suggested that further genetic factors may confer additional risk. We investigated the association of two single-nucleotide polymorphisms (SNPs), rs3212227 at the 3'-untranslated region and rs7709212 located at ~6.7 kb upstream from the transcription start site of IL12B gene in a case-control study comprising 1702 individuals from India. We found both SNPs were significantly associated with psoriasis (rs7709212: odds ratio (OR)=1.37, P-value=1.09 × 10-5; rs3212227: OR=1.38, P-value=8.88 × 10-6). IL12B gene was significantly upregulated in involved skin of psoriasis patients with risk genotype carriers (rs7709212_TT and rs3212227_TT) compared with non-risk genotype carriers (rs7709212_CC and rs3212227_GG). Significantly higher serum protein concentration of IL12 was also observed among risk allele carriers compared with non-risk allele carriers irrespective of the presence of HLA-Cw6 allele. Haplotype analysis suggested significant increased risk (OR=1.50, P-value=5.01 × 10-8) to the disease when both risk alleles of IL12B were present. IL12 serum protein concentration of risk haplotype (TT-TT) carriers showed significant upregulation compared with the non-risk carriers independent of HLA-Cw6 alleles. Our data suggested the association of IL12B with the psoriasis, however no evidence was observed for the epistatic effect of IL12B with HLA-Cw6 among the psoriasis patients in India.

Increased Risk of Psoriasis due to combined effect of HLA-Cw6 and LCE3 risk alleles in Indian population.

HLA-Cw6 is one of the most associated alleles in psoriasis. Recently, Late Cornified Envelop 3 (LCE3) genes were identified as a susceptibility factor for psoriasis. Some population showed epistatic interaction of LCE3 risk variants with HLA-Cw6, while some population failed to show any association. We determined the associations of a 32.2 kb deletion comprising LCE3C-3B genes and three SNPs (rs1886734, rs4112788; rs7516108) at the LCE3 gene cluster among the psoriasis patients in India. All three SNPs at the LCE3 gene cluster failed to show any association. In contrary, for patients with HLA-Cw6 allele, all three SNPs and the LCE3C-3B deletion showed significant associations. While, all five LCE3 genes were upregulated in psoriatic skin, only LCE3A showed significant overexpression with homozygous risk genotype compared to the non-risk genotype. LCE3B also showed significant overexpression in patients with HLA-Cw6 allele. Moreover, LCE3A showed significantly higher expression in patients bearing homozygous risk genotype in presence of HLA-Cw6 allele but not in those having non-risk genotype, demonstrating the combined effect of HLA-Cw6 allele and risk associated genotype near LCE3A gene. Integration of genetic and gene expression data thus allowed us to identify the actual disease variants at the LCE3 cluster among the psoriasis patients in India.

Genetic and epigenetic basis of psoriasis pathogenesis.

Psoriasis is a chronic inflammatory skin disease whose prevalence varies among different populations worldwide. It is a complex multi-factorial disease and the exact etiology is largely unknown. Family based studies have indicated a genetic predisposition; however they cannot fully explain the disease pathogenesis. In addition to genetic susceptibility, environmental as well as gender and age related factors were also been found to be associated. Recently, imbalances in epigenetic networks are indicated to be causative elements in psoriasis. The present knowledge of epigenetic involvement, mainly the DNA methylation, chromatin modifications and miRNA deregulation is surveyed here. An integrated approach considering genetic and epigenetic anomalies in the light of immunological network may explore the pathogenesis of psoriasis.

Evening primrose oil is effective in atopic dermatitis: a randomized placebo-controlled trial.

BACKGROUND: Atopic dermatitis (AD) is a chronic, relapsing, itchy dermatosis of multifactorial origin, which commonly starts in childhood. Defective metabolism of essential fatty acids leading to relative dominance of pro-inflammatory prostaglandins (PGE2 and PGF2) has been reported as an important factor in the pathogenesis of AD. Evening primrose oil (EPO) as a source of gamma-linolenic acid (GLA) has been of interest in the management of AD. AIM: To evaluate the efficacy and safety of EPO in atopic dermatitis in our patients. METHODS: Consecutive new out-patient department (OPD) patients of a referral hospital in Kolkata clinically diagnosed as having AD were randomly allocated to two groups. To the first group, evening primrose oil was supplied as 500-mg oval clear unmarked capsules, while placebo capsules identical in appearance and containing 300 mg of sunflower oil were given to the other group. Treatment continued for a period of 5 months. With pre-designed scoring system (based on four major parameters: extent, intensity, itching, and dryness), clinical evaluation was done at baseline and subsequent monthly visits. Data of the first 25 patients from each group who completed the 5 months of trial were compiled and analyzed. RESULTS: At the end of the fifth month, 24 (96%) patients of EPO group and 8 (32%) patients of placebo group showed improvement. There was significant difference in outcome of treatment between two groups (P<0.00001). No significant adverse effect was reported by any patient/guardian at any point of assessment. CONCLUSION: Evening primrose oil is a safe and effective medicine in management of AD. However, since not all researchers across the world have found the same good result, further large trials on Indian patients are needed.