TNIP1/ANXA6 and CSMD1 variants interacting with cigarette smoking, alcohol intake affect risk of psoriasis

Etiopathogenesis of Psoriasis: Integration of Proposed Theories

Psoriasis is a chronic inflammatory disease characterized by squamous and erythematous plaques on the skin and the involvement of the immune system. Global prevalence for psoriasis has been reported around 1-3% with a higher incidence in adults and similar proportions between men and women. The risk factors associated with psoriasis are both extrinsic and intrinsic, out of which a polygenic predisposition is a highlight out of the latter. Psoriasis etiology is not yet fully described, but several hypothesis have been proposed: 1) the autoimmunity hypothesis is based on the over-expression of antimicrobial peptides such as LL-37, the proteins ADAMTSL5, K17, and hsp27, or lipids synthesized by the PLA2G4D enzyme, all of which may serve as autoantigens to promote the differentiation of autoreactive lymphocytes T and unleash a chronic inflammatory response; 2) dysbiosis of skin microbiota hypothesis in psoriasis has gained relevance due to the observations of a loss of diversity and the participation of pathogenic bacteria such as Streptococcus spp. or Staphylococcus spp. the fungi Malassezia spp. or Candida spp. and the virus HPV, HCV, or HIV in psoriatic plaques; 3) the oxidative stress hypothesis, the most recent one, describes that the cell injury and the release of proinflammatory mediators and antimicrobial peptides that leads to activate of the Th1/Th17 axis observed in psoriasis is caused by a higher release of reactive oxygen species and the imbalance between oxidant and antioxidant mechanisms. This review aims to describe the mechanisms involved in the three hypotheses on the etiopathogeneses of psoriasis.

Sulforaphane alleviates psoriasis by enhancing antioxidant defense through KEAP1-NRF2 Pathway activation and attenuating inflammatory signaling

Psoriasis is a chronic inflammatory skin disease that affects millions of people worldwide. Sulforaphane (SFN) has been shown to have anti-inflammatory and antioxidant properties. In this study, we investigated the effects of SFN on a mouse model of psoriasis induced by imiquimod (IMQ) and its underlying molecular mechanism. Mice treated with SFN showed significant improvement in psoriatic symptoms, including reduced erythema, scales, and cutaneous thickness. Histopathological analysis and immunohistochemical staining revealed decreased expression of K16, K17, and Ki67 in SFN-treated mice, indicating reduced abnormal differentiation of keratinocytes and cutaneous inflammation. SFN treatment also reduced the activation of STAT3 and NF-κB pathways and downregulated pro-inflammatory cytokines IL-1β, IL-6, and CCL2. In vitro experiments using HaCaT cells demonstrated that SFN inhibited IL-22 and TNF-α-induced activation of inflammatory pathways and keratinocyte proliferation. Network pharmacology analysis suggested that the KEAP1-NRF2 pathway might be involved in the protective effects of SFN on psoriasis. We observed reduced NRF2 expression in human psoriatic lesions, and subsequent experiments showed that SFN activated KEAP1-NRF2 pathway in vivo and in vitro. Importantly, NRF2-deficient mice exhibited aggravated psoriasis-like symptoms and reduced response to SFN treatment. Our findings indicate that SFN ameliorates psoriasis symptoms and inflammation through the KEAP1-NRF2 pathway, suggesting a potential therapeutic role for SFN in the treatment of psoriasis.

Annexin A6 Polymorphism Is Associated with Pro-atherogenic Lipid Profiles and with the Downregulation of Methotrexate on Anti-Atherogenic Lipid Profiles in Psoriasis

BACKGROUND

Annexin A6 (AnxA6) is a lipid-binding protein that regulates cholesterol homeostasis and secretory pathways. However, the correlation of AnxA6 polymorphism with lipometabolism has never been studied in psoriasis.

OBJECTIVES

To investigate the impact of AnxA6 polymorphism on lipid profiles and the expression of AnxA6 protein in both peripheral blood mononuclear cells (PBMCs) and lipometabolism in psoriasis.

METHODS

A total of 265 psoriatic patients received methotrexate (MTX) treatment for 12 weeks, after which their lipid profiles were determined by measuring total cholesterol (TC), triglycerides (TGs), lipoprotein (a) [LP(a)], high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein (LDL), apolipoprotein (a)1 (ApoA1), and apolipoprotein B (ApoB). In addition, AnxA6 (rs11960458) was genotyped in 262 patients and the expression of AnxA6 in PBMCs was measured by Western blotting at baseline and week 8 post-MTX treatment.

RESULTS

The CC genotype carriers of rs11960458 had a lower expression of AnxA6 and lower levels of the pro-atherogenic lipids TC, LDL, and ApoB compared to TC genotype carriers. MTX significantly downregulated the levels of the anti-atherogenic lipids HDL-C and ApoA1 and the level of AnxA6 in TC genotype carriers, as well as the level of TGs in CC genotype carriers.

CONCLUSIONS

The polymorphism of AnxA6, rs11960458, was statistically associated with the levels of pro-atherogenic lipids and with the downregulation of MTX on the levels of anti-atherogenic lipids and TGs in psoriasis.

Prevalence and Predictors of Abdominal Aorta Calcification in Patients With Psoriasis—A Case Control Study

Background

Psoriasis is associated with a high prevalence of cardiovascular disease in Caucasians, but only a few studies from sub-Saharan Africa have investigated the prevalence of cardiovascular disease in patients with psoriasis. Abdominal aortic calcification (AAC) is a strong predictor of future cardiovascular events and all-cause mortality in the general population. We investigated the prevalence and risk factors for AAC in a predominantly non-Caucasian cohort of South African patients with psoriasis.

Methods

A cross-sectional case-control study of adult psoriasis patients (n = 69) and controls (n = 80), matched for gender, ethnicity and body mass index, attending tertiary Dermatology and Rheumatology clinics in Johannesburg, South Africa. Demographic, anthropometric, clinical and biochemical data were recorded. All participants underwent non-contrast abdominal CT scans. Images were assessed for AAC at the supra-coeliac aorta, supra-mesenteric aorta and aortic bifurcation using Horos DICOM viewer software.

Results

Abdominal aortic calcification at any site was more prevalent in the psoriasis than control group (47.8% vs 22.5%, p < 0.005). The aortic bifurcation was the commonest site for AAC in both groups, but more prevalent in the psoriasis group (42.0% vs 21.3%, p < 0.005). The psoriasis group was also more likely to smoke, have hypertension and type 2 diabetes (56.5% vs 25.0%, p < 0.005; 72.0% vs 55.0%, p < 0.005; 24.6% vs 3.80%, p < 0.0005, respectively). Multivariable logistic regression analysis demonstrated that age, smoking and type 2 (T2DM) diabetes were independently associated with AAC (odds ratio (95% CIs): 1.16 (1.07, 1.20), 4.30 (2.15, 8.61) and 3.45 (1.09, 15.7) respectively), but psoriasis was not. Forward regression analysis demonstrated that smoking attenuated the association of psoriasis with AAC.

Conclusion

Our findings show AAC to be more common in psoriasis patients compared to controls. Age, T2DM and smoking were independent predictors of AAC. Smoking cessation is essential in psoriatic patients to reduce the risk of cardiovascular events. The clinical utility of AAC detection by CT imaging to risk stratify for hard cardiovascular outcomes needs to be explored.

iTRAQ-based quantitative proteomics reveals biomarkers/pathways in psoriasis that can predict the efficacy of methotrexate

BACKGROUND

Methotrexate (MTX) is the first-line medicine to treat psoriasis. So far, there has been less research on protein biomarkers to predict its efficacy by the proteomic technique.

OBJECTIVES

To evaluate differentially expressed proteins in peripheral mononuclear cells (PBMCs) between good responders (GRs) and non-responders (NRs) after MTX treatment, compared with normal controls (NCs).

METHODS

We quantified protein expression of PBMCs with 4 GRs and 4 NRs to MTX and 4 NCs by isobaric tags for relative and absolute quantification (iTRAQ), analyzing and identifying proteins related to efficacy of MTX in 18 psoriatic patients.

RESULTS

A total of 3,177 proteins had quantitative information, and 403 differentially expressed proteins (fold change ≥ 1.2, p < .05) were identified. Compared to NCs, upregulated proteins (ANXA6, RPS27A, EZR, XRCC6), participating in the activation of NF-κB, the JAK-STAT pathway, and neutrophil degranulation were detected in GRs. The proteins (GPV, FN1, STOM), involving platelet activation, signaling and aggregation as well as neutrophil degranulation were significantly downregulated in GRs. These proteins returned to normal levels after MTX treatment. Furthermore, Western blotting identified the expression of ANXA6 and STAT1 in PBMCs, which were significantly downregulated in GRs, but not in NRs.

CONCLUSIONS

We identified seven differentially expressed and regulated proteins (ANXA6, GPV, FN1, XRCC6, STOM, RPS27A, and EZR) as biomarkers to predict MTX efficacy in NF-κB signaling, JAK-STAT pathways, neutrophil degranulation, platelet activation, signaling and aggregation.

Effects of tobacco and vaping on the skin

Cigarette and electronic cigarette use are significant public health concerns across the United States. Tobacco use remains the single most preventable cause of morbidity and mortality in the world. Electronic cigarettes initially emerged as a better alternative to conventional cigarettes and for promoting smoking cessation; however, current evidence reveals similar deleterious health implications caused by both products on almost all organ systems, including the skin. Recognition of the cutaneous manifestations associated with cigarette and electronic cigarette use is essential for dermatologists in current clinical practice. Dermatologists play a vital role in educating and counseling patients on smoking cessation. We specifically highlight the cutaneous consequences of conventional cigarette smoking and electronic cigarettes on dermatologic disease.

Quality Control of DNA Extracted from All-Cell Pellets After Cryopreservation for More Than 10 Years

Background: Cryopreserved whole blood, all-cell pellets (ACPs), and buffy coats in biobanks are widely used to obtain DNA for genetic testing. However, there are few studies concerning the quality control of DNA extracted from them. Our research aimed to perform quality control of DNA extracted from ACPs after cryopreservation for >10 years. Materials and Methods: A total of 1377 ACP samples (separated from 3 mL of whole blood) were retrieved from our biobank, where they had been cryopreserved for 10-15 years. Chemagic STAR was used to extract the DNA. Absorbance at A260, A280, and A230 were measured by spectrophotometry, and integrity was analyzed by agarose gel electrophoresis. The quality thresholds for an Illumina Asian Screening Array (ASA) were yields greater than 0.5 μg, concentration of 25-150 ng/μL, A260/280 ratio of 1.6-2.1, and no degradation fragments in the electrophoresis gel. Results: The median yield of genomic DNA was 54.30 μg (interquartile range [IQR] 35.55-74.64). The median A260/280 and A260/230 ratios were 1.90 (IQR 1.87-1.94) and 1.98 (IQR 1.64-2.41), respectively. In total, 1377 samples (100%) had qualified yields, and 1366 samples (99.20%) had qualified integrity results. Finally, 1328 (96.44%) samples were used for ASA. Of the remaining samples, 34 needed to be repurified, 4 were obtained at an insufficient concentration, and 11 were unqualified for integrity. In addition, we analyzed the influence of hemolysis (90 samples) and clots (102 samples) on the quality of DNA samples. Hemolysis and clotting did not influence yield or integrity, but a significant difference was found in A260/230 compared to normal samples (p < 0.05). Furthermore, the samples (14 samples) with both hemolysis and clots had higher A260/280 (p < 0.05). Conclusion: ACP samples stored for >10 years at -80°C produced DNA with high quality for use in genetic analysis. Hemolysis and clots in the ACPs led to lower purity, but did not significantly affect yield or integrity.

The Impact of ANxA6 Gene Polymorphism on the Efficacy of Methotrexate Treatment in Psoriasis Patients

BACKGROUND

There are great interindividual variations in the clinical efficacy of methotrexate (MTX) treatment and patients' genetic background seems promising in its explanation.

OBJECTIVES

The study aimed to test whether the polymorphism of annexin A6 (ANxA6) gene, a susceptibility factor for psoriasis, was associated with the clinical response to MTX therapy.

METHODS

A total of 325 patients enrolled in the study received oral MTX treatment, of whom 310 completed the 1-year study and performed the genotype analysis. They were defined as responders (a reduction of Psoriasis Area and Severity Index [PASI] score ≥75%) and nonresponders (a reduction of PASI <50%) compared to baseline after 12 weeks of short-time therapy. On 1-year treatment, they were defined as responders if they achieved PASI75 and absolute PASI ≤3, otherwise as nonresponders. The genotypes of 4 single-nucleotide polymorphisms (SNPs) in the ANxA6 gene were verified using the Sequenom platform. Potential predictors associated with the treatment outcome of MTX were assessed by binary logistic regression.

RESULTS

We found significant associations for the ANxA6 SNPs of rs11960458, rs960709, and rs13168551 with psoriasis severity. Patients with rs11960458 CC genotype and rs960709 GG genotype showed higher percentages of PASI75 and improvement rates of PASI at 12 weeks. And on 1-year treatment, statistical difference occurred in rs11960458 rather than other SNPs compared between responders and nonresponders that the frequency of CC genotype was higher in responders (p = 0.019). After adjustment for potential confounders, patients with rs11960458 TT/CT genotype (at 12 weeks: OR 0.483, 95% CI 0.245-0.951, p = 0.035; at 1 year: OR 0.483, 95% CI 0.280-0.833, p = 0.009) were significantly more likely to not respond to MTX both on the short-term and long-term treatment, while rs960709 and rs13168551 polymorphisms were only associated with the short-term efficacy of MTX (p = 0.018 and p = 0.036, respectively).

CONCLUSIONS

The CC ge-notype of ANxA6 (rs11960458) was significantly associated with a better response when compared to those patients with the TT/CT genotype, thus being a potential predictor for the clinical efficacy of MTX.

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.

Importance of Redox Equilibrium in the Pathogenesis of Psoriasis-Impact of Antioxidant-Rich Diet

Psoriasis is a common, chronic, hyperproliferative, inflammatory skin disease occurring in most ethnic groups in the world. The disease is hereditary but the process of its inheritance is complex and still not fully understood. At the same time, it has been observed that psoriatic lesions may be triggered by certain prooxidative external factors: using narcotics, smoking, drinking alcohol, physical and mental stress, as well as bacterial infections and injury. Since the main physiological marker of psoriasis relates to disorders in the organism's antioxidative system, it is necessary to develop a well-balanced combination of pharmaceuticals and dietary antioxidants to facilitate the effective treatment and/or prevention of the disease. The dietary sources of antioxidants must be adequate for chronic use regardless of the patient's age and be easily available, e.g., as ingredients of regular food or dietary supplements. Diet manipulation is a promising therapeutic approach in the context of modulating the incidence of chronic diseases. Another potentially viable method entails the use of nutrigenomics, which guarantees a multiaspectual approach to the problem, including, in particular, analyses of the genetic profiles of psoriasis patients with the view to more accurately targeting key problems. The present paper pertains to the significance of redox equilibrium in the context of psoriasis. Based on information published in worldwide literature over the last decade, the impact of dietary exogenous antioxidants on the course of this chronic disease was analysed.

Endoplasmic reticulum aminopeptidase 1 (ERAP1) polymorphisms and psoriasis susceptibility: A systematic review and meta-analysis

BACKGROUND

Psoriasis has a complex genetic background with a strong heritable component. Herein, the present meta-analysis aims to evaluate the association of ERAP1 polymorphisms with psoriasis susceptibility.

METHODS

PubMed, Web of Sciences, Scopus, and Cochrane Library databases were examined with no time limits up to March 2019, without language, age, and sex restrictions. The odds ratio (OR) and 95% confidence interval (CI) were calculated by CMA 2.0 software in a dichotomous analysis using computed effect sizes and having OR and confidence limits for each study. The subgroup analysis based on ethnicity, type of study, and genotyping method was performed.

RESULTS

Thirteen articles were involved in the meta-analysis, in details eight were cohort studies and five were case-control studies. The results showed an association between rs27524 [OR = 1.179; 95%CI: 1.081, 1.286; p < 0.001] and rs30187 [OR = 1.237; 95%CI: 1.133, 1.351; p < 0.001] polymorphisms and psoriasis susceptibility; whereas no association was detected with rs26653 [OR = 1.013; 95%CI: 0.798, 1.286; p = 0.914] and rs27044 [OR = 1.164; 95%CI: 0.982, 1.381; p = 0.080] polymorphisms. Psoriasis susceptibility in both Caucasian and Asian ethnicities was related to rs27524 polymorphism, while rs30187 and rs27044 polymorphisms were over-represented in patients belonging to Caucasian ethnicity. In addition, in cohort studies, psoriasis susceptibility was related to rs27524 polymorphism, while the associated polymorphisms were rs26653 and rs27044 in case-control studies, and rs30187 in both cohort and case-control studies.

CONCLUSIONS

These findings showed an association between rs27524 and rs30187 polymorphisms and susceptibility to psoriasis, while lack of association was obtained for rs26653 and rs27044 polymorphisms. In order to confirm our results, further studies are needed, also considering different factors, such as type of psoriasis and ethnicity.

Genome-Wide Association Study of Smoking Behavior Traits in a Chinese Han Population

Tobacco use is one of the leading causes of preventable disease worldwide. Genetic studies have elucidated numerous smoking-associated risk loci in American and European populations. However, genetic determinants for cigarette smoking in Chinese populations are under investigated. In this study, a whole-genome sequencing (WGS)-based genome-wide association study (GWAS) was performed in a Chinese Han population comprising 620 smokers and 564 nonsmokers. Thirteen single-nucleotide polymorphisms (SNPs) of the raftlin lipid linker 1 (RFTN1) gene achieved genome-wide significance levels (P < 5 x 10^-8) for smoking initiation. The rs139753473 from RFTN1 and six other suggestively significant loci from CUB and sushi multiple domains 1 (CSMD1) gene were also associated with cigarettes per day (CPD) in an independent Chinese sample consisting of 1,329 subjects (805 smokers and 524 nonsmokers). When treating males separately, associations between smoking initiation and PCAT5/ANKRD30A, two genes involved in cancer development, were identified and replicated. Within RFTN1, two haplotypes (i.e., C-A-C-G and A-G-T-C) formed by rs796812630-rs796584733-rs796349027-rs879511366 and three haplotypes (i.e., T-T-C-C-C, T-T-A-T-T, and C-A-A-T-T) formed by rs879401109-rs879453873-rs75180423-rs541378415-rs796757175 were strongly associated with smoking initiation. In addition, we also revealed two haplotypes (i.e., C-A-G-G and T-C-T-T derived from rs4875371-rs4875372-rs17070935-rs11991366) in the CSMD1 gene showing a significant association with smoking initiation. Further bioinformatics functional assessment suggested that RFTN1 may participate in smoking behavior through modulating immune responses or interactions with the glucocorticoid receptor alpha and the androgen receptor. Together, our results may help understand the mechanisms underlying smoking behavior in the Chinese Han population.

Multi-omics study in monozygotic twins confirm the contribution of de novo mutation to psoriasis

BACKGROUND

Genome-wide association studies have identified over 120 risk loci for psoriasis. However, most of the variations are located in non-coding region with high frequency and small effect size. Pathogenetic variants are rarely reported except HLA-C*0602 with the odds ratio being approximately 4.0 in Chinese population. Although rare variations still account for a small proportion of phenotypic variances in complex diseases, their effect on phenotypes is large. Recently, more and more studies focus on the low-frequency functional variants and have achieved a certain amount of success.

METHOD

Whole genome sequencing and sanger sequencing was performed on 8 MZ twin pairs discordant for psoriasis to scan and verified the de novo mutations (DNMs). Additionally, 665 individuals with about 20 years' medical history versus 2054 healthy controls and two published large population studies which had about 8 years' medical history (including 10,727 cases versus 10,582 controls) were applied to validate the enrichment of rare damaging mutations in two DNMs genes. Besides, to verify the pathogenicity of candidate DNM in C3, RNA-sequencing for CD4⁺, CD8⁺ T cells of twins and lesion, non-lesion skin of psoriasis patients were carried out. Meanwhile, the enzyme-linked immunosorbent assay kit was used to detect the level of C3, C3b in the supernatant of peripheral blood.

RESULT

A total of 27 DNMs between co-twins were identified. We found six of eight twins carry HLA-C∗0602 allele which have large effects on psoriasis. And it is interesting that a missense mutation in SPRED1 and a splice region mutation in C3 are found in the psoriasis individuals in the other two MZ twin pairs without carrying HLA-C*0602 allele. In the replication stage, we found 2 loss-of-function (LOF) variants of C3 only in 665 cases with about 20 years' medical history and gene-wise analysis in 665 cases and 2054 controls showed that the rare missense mutations in C3 were enriched in cases (OR = 1.91, P = 0.0028). We further scanned the LOF mutations of C3 in two published studies (about 8 years' medical history), and found one LOF mutation in the case without carrying HLA-C*0602. In the individual with DNM in C3, RNA sequencing showed the expression level of C3 in skin was significant higher than healthy samples in public database (TPM fold change = 1.40, P = 0.000181) and ELISA showed protein C3 in peripheral blood was higher (~2.2-fold difference) than the other samples of twins without DNM in C3.

CONCLUSION

To the best of our knowledge, this is the first report that DNM in C3 is the likely pathological mutations, and it provided a better understanding of the genetic etiology of psoriasis and additional treatments for this disease.

Genetics of psoriasis: a basis for precision medicine

Psoriasis is an inflammatory skin disease with a background of polygenic inheritance. Both environmental and genetic factors are involved in the etiology of the disease. In the last two decades, numerous studies have been conducted through linkage analysis, genome-wide association study (GWAS), and direct sequencing to explore the role of genetic variation in disease pathogenesis and progression. To date, >80 psoriasis susceptibility genes have been identified, including HLA-Cw6, IL12B, IL23R, and LCE3B/3C. Some genetic markers have been applied in disease prediction, clinical diagnosis, treatment, and new drug development, which could further explain the pathogenesis of psoriasis and promote the development of precision medicine. This review summarizes related research on genetic variation in psoriasis and explores implications of the findings in clinical application and the promotion of a personalized medicine project.

The Role of Cell Adhesion Molecule Genes Regulating Neuroplasticity in Addiction

A variety of genetic approaches, including twin studies, linkage studies, and candidate gene studies, has established a firm genetic basis for addiction. However, there has been difficulty identifying the precise genes that underlie addiction liability using these approaches. This situation became especially clear in genome-wide association studies (GWAS) of addiction. Moreover, the results of GWAS brought into clarity many of the shortcomings of those early genetic approaches. GWAS studies stripped away those preconceived notions, examining genes that would not previously have been considered in the study of addiction, consequently creating a shift in our understanding. Most importantly, those studies implicated a class of genes that had not previously been considered in the study of addiction genetics: cell adhesion molecules (CAMs). Considering the well-documented evidence supporting a role for various CAMs in synaptic plasticity, axonal growth, and regeneration, it is not surprising that allelic variation in CAM genes might also play a role in addiction liability. This review focuses on the role of various cell adhesion molecules in neuroplasticity that might contribute to addictive processes and emphasizes the importance of ongoing research on CAM genes that have been implicated in addiction by GWAS.

Psoriasis and smoking: links and risks

Smoking is a complex environmental exposure influenced by genetic, environmental, and social factors. Nicotine is the principal alkaloid in tobacco that mediates the addicting effects of tobacco products. Tobacco is a mixture of more than 7,000 chemicals, and smoking is recognized as a risk factor for many diseases in humans, including cardiovascular and pulmonary disease and several cancers, and is the single most preventable cause of mortality worldwide. A number of inflammatory immune-related conditions have been associated with smoking, including psoriasis. Smoking affects the onset of psoriasis. In a pooled analysis of 25 case-control studies, the odds ratio of psoriasis among smokers was 1.78 (95% confidence interval [CI]: 1.53-2.06). A dose-effect relationship is also documented. In a pooled analysis of three cohort studies, the risk of incident psoriasis was 1.81 (95% CI: 1.38-2.36) in those who smoked 1-14 cigarettes per day, and 2.29 (95% CI: 1.74-3.01) in those who smoked ≥25 cigarettes per day. Smoking also impacts on the clinical severity of psoriasis, its response to treatment, and explains some of the associated comorbidities, eg, cardiovascular disease, inflammatory bowel disease, and several cancers (especially those of the respiratory tract). Data on the role of smoking in psoriatic arthritis are less consistent compared with those concerning psoriasis. Several pathophysiological mechanisms may explain the association of psoriasis with smoking, including oxidative stress, interaction with signaling pathways active in psoriasis, and vascular influences. In conclusion, psoriasis is just one of the many diseases associated with smoking, but it is visible and disabling. Dermatologists could play a major role in reducing the health burden of smoking by influencing the patients to change their behavior.

Current knowledge on psoriasis and autoimmune diseases

Psoriasis is a prevalent, chronic inflammatory disease of the skin, mediated by crosstalk between epidermal keratinocytes, dermal vascular cells, and immunocytes such as antigen presenting cells (APCs) and T cells. Exclusive cellular “responsibility” for the induction and maintenance of psoriatic plaques has not been clearly defined. Increased proliferation of keratinocytes and endothelial cells in conjunction with APC/T cell/monocyte/macrophage inflammation leads to the distinct epidermal and vascular hyperplasia that is characteristic of lesional psoriatic skin. Despite the identification of numerous susceptibility loci, no single genetic determinant has been identified as responsible for the induction of psoriasis. Thus, numerous other triggers of disease, such as environmental, microbial and complex cellular interactions must also be considered as participants in the development of this multifactorial disease. Recent advances in therapeutics, especially systemic so-called “biologics” have provided new hope for identifying the critical cellular targets that drive psoriasis pathogenesis. Recent recognition of the numerous co-morbidities and other autoimmune disorders associated with psoriasis, including inflammatory bowel disease, multiple sclerosis, rheumatoid arthritis, and systemic lupus erythematosus suggest common signaling elements and cellular mediators may direct disease pathogenesis. In this review, we discuss common cellular pathways and participants that mediate psoriasis and other autoimmune disorders that share these cellular signaling pathways.

Smoking and risk for psoriasis: a population-based twin study

BACKGROUND

Smoking is a potential risk factor for psoriasis. Both psoriasis and smoking habits are partly explained by genetic factors. However, twin studies investigating the association between these traits are limited.

METHODS

Questionnaire-based data on smoking habits and psoriasis were collected for 34,781 twins, aged 20-71 years, from the Danish Twin Registry. A co-twin control analysis was performed on 1700 twin pairs discordant for lifetime history of smoking. Genetic and environmental correlations between smoking and psoriasis were estimated using classical twin modeling.

RESULTS

After multivariable adjustment, age group (50-71 vs. 20-49 years) and childhood exposure to environmental tobacco smoke (ETS) were significantly associated with psoriasis in the whole population (odds ratio [OR] 1.15, 95% confidence interval [CI] 1.02-1.29 [P = 0.021] and OR 1.28, 95% CI 1.10-1.49 [P = 0.002], respectively). Risk for psoriasis increased substantially (OR 2.18, 95% CI 1.82-2.61; P < 0.001) for smokers with a history of >5 pack-years, even after adjusting for age, sex, and childhood ETS. Among twin pairs discordant for smoking, risk for psoriasis in the ever-smoking twin was lower among monozygotic twins (OR 1.23, 95% CI 0.59-2.56; P = 0.578) than among same-sex dizygotic twins (OR 2.21, 95% CI 1.36-3.58; P = 0.001). Genetic factors explained 20% (14-25%; P < 0.001) of the correlation between psoriasis and smoking, whereas non-shared environmental factors explained 8% (0-22%; P = 0.504).

CONCLUSIONS

Tobacco consumption and childhood ETS are significantly associated with psoriasis. Results indicate shared genetic factors for smoking and psoriasis.

A weighted polygenic risk score using 14 known susceptibility variants to estimate risk and age onset of psoriasis in Han Chinese

With numbers of common variants identified mainly through genome-wide association studies (GWASs), there is great interest in incorporating the findings into screening individuals at high risk of psoriasis. The purpose of this study is to establish genetic prediction models and evaluate its discriminatory ability in psoriasis in Han Chinese population. We built the genetic prediction models through weighted polygenic risk score (PRS) using 14 susceptibility variants in 8,819 samples. We found the risk of psoriasis among individuals in the top quartile of PRS was significantly larger than those in the lowest quartile of PRS (OR = 28.20, P < 2.0×10^-16). We also observed statistically significant associations between the PRS, family history and early age onset of psoriasis. We also built a predictive model with all 14 known susceptibility variants and alcohol consumption, which achieved an area under the curve statistic of ~ 0.88. Our study suggests that 14 psoriasis known susceptibility loci have the discriminating potential, as is also associated with family history and age of onset. This is the genetic predictive model in psoriasis with the largest accuracy to date.

Recent advances in atopic dermatitis and psoriasis: genetic background, barrier function, and therapeutic targets

Atopic dermatitis (AD) and psoriasis are common inflammatory skin diseases. Although clinical pictures of these two diseases are quite different, they share some common pathological backgrounds such as barrier dysfunction and enhanced IL-22 expression. To explain the clinical differences of the diseases, it has been proposed that Th2/Th22-polarized immune status together with an attenuated Th17 axis may cause insufficient induction of antimicrobial peptides and more severe barrier dysfunction in AD. While skin barrier dysfunction is commonly seen in AD and psoriasis, a Th2-dominant cytokine milieu down-regulates immunity against infections, which are commonly seen in lesional skin of AD. In the era of biologics, increase in the understanding or new discoveries of molecules involved in the development of various diseases will instantly lead to a new therapeutic strategy. In this review, we give an overview of recent advances in AD and psoriasis, especially on genetic background, barrier function, and therapeutic targets.

Psoriasis and smoking: a systematic review and meta-analysis

Psoriasis is an inflammatory skin disease associated with increased cardiovascular comorbidity. Smoking is associated with an increased risk of cardiovascular disease, and prior studies have suggested that patients with psoriasis are more likely to be active smokers. Smoking may also be a risk factor in the development of psoriasis. We conducted a systematic review and meta-analysis to assess the prevalence of smoking among patients with psoriasis, and we reviewed the contribution of smoking to the incidence of psoriasis. A total of 25 prevalence and three incidence studies were identified. The meta-analysis of prevalence studies included a total of 146 934 patients with psoriasis and 529 111 patients without psoriasis. Random effects meta-analysis found an association between psoriasis and current smoking [pooled odds ratio (OR) 1·78, 95% confidence interval (CI) 1·52-2·06], as well as between psoriasis and former smoking (pooled OR 1·62, 95% CI 1·33-1·99). Meta-regression analysis did not reveal any sources of study heterogeneity, but a funnel plot suggested possible publication bias. A subset of studies also examined the association between moderate-to-severe psoriasis and smoking, with a pooled OR of 1·72 (95% CI 1·33-2·22) for prevalent smoking. The three incidence studies found an association between smoking and incidence of psoriasis, with a possible dose-effect of smoking intensity and duration on psoriasis incidence. These findings suggest that smoking is an independent risk factor for the development of psoriasis, and that patients with established psoriasis continue to smoke more than patients without psoriasis.

Combined effects of the BDNF rs6265 (Val66Met) polymorphism and environment risk factors on psoriasis vulgaris

Smoking, alcohol consumption and higher body mass index (BMI) are well established risk factors for psoriasis and also associated with the clinical traits of the disease. And the genetic influences on these three risk factors indeed exist. Previously studies have demonstrated these risk factors related genetic variants may also play a role in the development of risk factors-related diseases. Then we performed a hospital-based study in order to evaluate the combined effect of the risk factors and their related polymorphism rs6265 in brain-derived neurotrophic factor (BDNF) gene on psoriasis vulgaris (PV) risk and clinic traits. The case-control study involved 660 subjects including 345 cases and 315 controls in Chinese Han population. The variant of rs6265 was typed by SNaPshot Multiplex Kit (Applied Biosystems Co., USA). We confirmed that higher BMI (≥25), smoking and alcohol consumption were risk factors for PV, and the estimated ORs were 1.63(95 % confidence interval (CI); 1.12-2.37), 2.09(95 % CI; 1.44-3.03) and 1.65(95 % CI; 1.15-2.37) respectively. Genotype and allele distributions did not differ significantly between case and control. However, we found combined effect of rs6265 genotype (GG) and higher BMI (≥25) increased risk of PV (OR = 2.09; 95 % CI, 1.02-4.28; P < 0.05; adjusted OR = 3.19; 95 % CI, 1.37-7.45; P < 0.05) and clinically severity of PV (OR = 2.71; 95 % CI, 1.09-6.72; P < 0.05; adjusted OR = 1.25; 95 % CI, 1.10-1.40; P < 0.05). But none such significant combined effect was observed between others genotype (AA and AG) and other risk factors. In conclusions, the combined effect of BDNF rs6265 genotype (GG) and higher BMI may increases the risk and clinical severity of PV in Chinese Han population.

Combined effect between CHRNB3-CHRNA6 region gene variant (rs6474412) and smoking in psoriasis vulgaris severity

BACKGROUND

Many factors associated with causing psoriasis have been reported, such as the genetic and environmental factors. Smoking is one of the well-established environmental risk factors for psoriasis and also associated with the disease severity. In addition, several studies of psoriasis and psoriatic arthritis have documented gene-environment interactions involving smoking behavior. Although gene polymorphisms on nicotinic acetylcholine receptor subunits CHRNB3-CHRNA6 region gene have been found to correlate with smoking behavior and lung cancer susceptibility in Chinese Han population, the combined effect between the smoking-related genetic variants and smoking behavior on psoriasis vulgaris (PV) has been unreported.

OBJECTIVE

To evaluate the combined effect of the smoking-related (rs6474412-C/T) polymorphism on CHRNB3-CHRNA6 region gene and smoking behavior on PV risk and clinic traits in Chinese Han population.

METHODS

A hospital-based case-control study including 672 subjects (355 PV cases and 317 controls) was conducted. The variant of rs6474412 was typed by SNaPshot Multiplex Kit (Applied Biosystems Co., USA).

RESULTS

The higher body mass index (BMI≥25), smoking behavior and alcohol consumption were risk factors for PV, and the estimated ORs were 1.55 (95% CI, 1.09-2.29), 1.74 (95% CI, 1.22-2.49) and 1.81 (95% CI, 1.25-2.62) respectively. The smoking patients had more severe conditions than non-smokers (OR=1.71, 95% CI, 1.08-2.70, P=0.020). The alleles and genotypes of rs6474412 were not associated with risk of PV, but the combined effect of rs6474412 genotype (TT) and smoking behavior increased severity of PV (OR=5.95; 95% CI, 1.39-25.31; P<0.05; adjusted OR=2.20; 95% CI, 1.55-3.14; P<0.001).

CONCLUSIONS

Our results demonstrate that the combined effect of rs6474412-C/T polymorphism in smoking-related CHRNB3-CHRNA6 region gene and smoking behavior may not confer risk to PV, but may have impact on PV severity in Chinese Han population.