Anna-Karin Ekman

Genetic support for the role of the NLRP3 inflammasome in psoriasis susceptibility

NACHT leucine‐rich repeat‐ and PYD‐containing (NLRP)3 protein controls the inflammasome by regulating caspase‐1 activity and interleukin (IL)‐1β processing. The contribution of IL‐1β in the pathogenesis of psoriasis is well recognized. Polymorphisms in NLRP3 and caspase recruitment domain–containing protein (CARD)8, a negative regulator of caspase‐1 activity, have been associated with susceptibility to common inflammatory diseases, such as Crohns disease and rheumatoid arthritis. To investigate the role for genetic variants in the NLRP3 inflammasome in psoriasis susceptibility. In a patient sample comprising 1988 individuals from 491 families and 1002 healthy controls, genotypes for four selected single‐nucleotide polymorphisms (SNPs) in NLRP3 (three SNPs) and CARD8 (one SNP) were determined by TaqMan® Allelic Discrimination. Using the transmission disequilibrium test (TDT), a significant increase in the transmission of the NLRP3 rs10733113G genotype to a subgroup of patients with more widespread psoriasis was demonstrated (P = 0.015). Using logistic regression analysis in 741 patients with psoriasis and 1002 controls, the CARD8 rs2043211 genotype was significantly different in cases and controls in overall terms [OR 1.3 (1.1–1.5), P = 0.004] and for both genders. Our data support the hypothesis that the inflammasome plays a role in psoriasis susceptibility.

Systemic treatment and narrowband ultraviolet B differentially affect cardiovascular risk markers in psoriasis

BACKGROUND Psoriasis is associated with a systemic inflammation and an increased frequency of the metabolic syndrome, both of which are believed to link psoriasis to an increased risk of cardiovascular disease. OBJECTIVE The study aimed to investigate the systemic expression of markers of cardiovascular risk and determine their response to ultraviolet B therapy and treatment with the tumor necrosis factor-alfa inhibitor, etanercept. METHODS Six markers of cardiovascular risk were measured in 28 patients with psoriasis and 28 control subjects. RESULTS Five of the 6 investigated markers were elevated in patients with psoriasis. Four of these correlated to the body mass index and waist-hip ratio, suggesting a link to the metabolic syndrome. Total plasminogen activator inhibitor-1 remained elevated independently of these factors. The levels of the investigated risk markers decreased considerably after tumor necrosis factor-alfa inhibitor treatment but remained unaffected by ultraviolet therapy. LIMITATIONS A relatively limited study population and nonrandomization are limitations. CONCLUSION These findings suggest that the choice of treatment in psoriasis may influence the cardiovascular risk in patients with psoriasis and the metabolic syndrome.

Genetic variations of NLRP1 : susceptibility in psoriasis

NACHT, LRR and PYD domain‐containing protein (NLRP)1 is part of the inflammasome multiprotein complex involved in the production of interleukin (IL)‐1β and IL‐18, two cytokines strongly implicated in psoriasis pathogenesis. Genetic variations in NLRP1 are associated with a predisposition for chronic inflammatory conditions.

Systemically Elevated Th1-, Th2- and Th17-associated Chemokines in Psoriasis Vulgaris Before and After Ultraviolet B Treatment

Chemokines may contribute to the systemic inflammation that is linked to the increased risk of co-morbidities in patients with psoriasis. The aim of this study was to investigate circulating chemokines in patients with psoriasis and their relationship to disease severity. Analysis of plasma levels of chemokines in patients with psoriasis before narrowband ultraviolet B (UVB) therapy revealed increased expression of Th1-associated CXCL9 and -10, Th2-associated CCL17 and CCL22, and Th17-associated CCL20. CCL20 correlated with disease severity. UVB therapy reduced skin symptoms, but did not affect the chemokine levels in plasma. Anti-CD3 and anti-CD28-mediated activation of peripheral blood mononuclear cells (PBMCs) caused a higher secretion of Th2 cytokine interleukin (IL)-13 by PBMCs from patients with psoriasis than from healthy controls. The sustained high expression of inflammatory chemokines is a potential link to systemic inflammation in psoriasis. UVB therapy may be a more effective treatment of local rather than systemic inflammation.

Overexpression of Psoriasin (S100A7) Contributes to Dysregulated Differentiation in Psoriasis.

Psoriasin, which is highly expressed in psoriasis, is encoded by a gene located within the epidermal differentiation complex. The aim of this study was to investigate the effect of endogenous psoriasin on disturbed keratinocyte differentiation in psoriasis. Immunohistochemical staining revealed a gradient of psoriasin expression in the psoriatic epidermis with highest expression in the suprabasal, differentiated layers. Induction of keratinocyte differentiation caused concurrent expression of psoriasin and the differentiation marker involucrin. The differentiation-induced psoriasin expression was found to be mediated by the protein kinase C pathway. The downregulation of psoriasin expression by small interfering RNA revealed that psoriasin mediates the expression of involucrin, desmoglein 1, transglutaminase 1 and CD24 in normal differentiation. The lentivirus-mediated overexpression of psoriasin, mimicking the psoriatic milieu, gave rise to an altered regulation of differentiation genes and an expression pattern reminiscent of that in psoriatic epidermis. These findings suggest that psoriasin contributes to the dysregulated differentiation process in the psoriasis epidermis.

Lack of preclinical support for the efficacy of histone deacetylase inhibitors in the treatment of psoriasis.

Lack of preclinical support for the efficacy of histone deacetylase inhibitors in the treatment of psoriasis.

Psoriasin (S100A7) promotes stress‐induced angiogenesis

Vascular modifications occur early in the development of psoriasis, and angiogenesis is one of the key features in the pathogenesis of the disease.

Genome-Wide DNA Methylation Profiling Identifies Differential Methylation in Uninvolved Psoriatic Epidermis

Psoriasis is a chronic inflammatory skin disease with both local and systemic components. Genome-wide approaches have identified more than 60 psoriasis-susceptibility loci, but genes are estimated to explain only one-third of the heritability in psoriasis, suggesting additional, yet unidentified, sources of heritability. Epigenetic modifications have been linked to psoriasis and altered DNA methylation patterns in psoriatic versus healthy skin have been reported in whole-skin biopsies. In this study, focusing on epigenetic modifications in the psoriatic uninvolved skin, we compared the lesional and non-lesional epidermis from psoriasis patients with epidermis from healthy controls. We performed an exhaustive genome-wide DNA methylation profiling using reduced representation bisulfite sequencing, which interrogates the methylation status of approximately 3-4 million CpG sites. More than 2,000 strongly differentially methylated sites were identified and a striking overrepresentation of the Wnt and cadherin pathways among the differentially methylated sites was found. In particular, we observe a strong differential methylation in several psoriasis candidate genes. A substantial number of differentially methylated sites present in the uninvolved versus healthy epidermis suggests the presence of a pre-psoriatic state in the clinically healthy skin type. Our exploratory study represents a starting point for identifying biomarkers for psoriasis-prone skin before disease onset.