The Q705K polymorphism in NLRP3 has been implicated in several chronic inflammatory diseases. In this study we determine the functional role of this commonly occurring polymorphism using an in-vitro system. NLRP3-WT and NLRP3-Q705K were retrovirally transduced into the human monocytic cell line THP-1, followed by the assessment of IL-1β and IL-18 levels in the cell culture supernatant. THP-1 cells expressing the above NLRP3 variants were sorted based upon Green Fluorescent Protein (GFP) expression. Cytokine response to alum (one of the most widely used adjuvants in vaccines) in the cells stably expressing NLRP3-WT and NLRP3-Q705K were determined. IL-1β and IL-18 levels were found to be elevated in THP-1 cells transduced with NLRP3-Q705K compared to the NLRP3-WT. Upon exposure to alum, THP-1 cells stably expressing NLRP3-Q705K displayed an increased release of IL-1β, IL-18 and TNF-α, in a caspase-1 and IL-1 receptor-dependent manner. Collectively, these findings show that the Q705K polymorphism in NLRP3 is a gain-of-function alteration leading to an overactive NLRP3 inflammasome. The option of IL-1β blockade may be considered in patients with chronic inflammatory disorders that are unresponsive to conventional treatments.

Summary: Genetic variants of NLRP3 and NLRP1 are known to modulate levels of pro‐inflammatory cytokine interleukin (IL)‐1β. The purpose of this study was to investigate the association of NLRP3/NLRP1 polymorphisms with susceptibility and clinical features of malignant melanoma in a Swedish case–control study. Common variants in NLRP3/NLRP1 were investigated in sporadic malignant melanoma patients and healthy controls followed by analysis using logistic regression. NLRP3 variant (rs35829419) was significantly more common in male patients than in controls (OR, 2.22; CI, 1.27–3.86). Upon stratification, significant association with nodular melanoma was observed (OR, 2.89; CI, 1.33–6.30), which intensified in male patients (OR 4.03, CI 1.40–11.59). The NLRP1 variant (rs12150220) was significantly more common in fair‐skinned female patients (OR, 1.85; CI, 1.04–3.33) and showed strong associations with nodular melanoma (OR, 6.03; CI, 1.33–25). Our data suggest that NLRP3/NLRP1 polymorphisms are associated with melanoma susceptibility; these findings warrant validation in other independent populations.

Objective The NALP3 inflammasome is a multiprotein complex that triggers caspase 1–mediated interleukin‐1β (IL‐1β) release. Mutations in the gene encoding NALP3 (NLRP3) underlie the cryopyrin‐associated periodic syndrome (CAPS). The aim of this study was to report a novel NLRP3 mutation in 2 siblings of Swedish descent in whom symptoms first presented in adulthood. Methods Mutation analysis of NLRP3 was performed on DNA from patients with CAPS and 100 control subjects. For assessment of caspase 1 and IL‐1β, blood was collected from patients and age‐ and sex‐matched healthy control subjects. Genetic constructs containing mutant or wild‐type NLRP3 were transduced into THP‐1 cells, followed by assessment of IL‐1β levels in cell supernatant. Results Both siblings carried a novel M299V mutation in NLRP3, which was not present in the control population. The samples obtained from the patients displayed increased caspase 1 activity and elevated IL‐1β levels at basal conditions as compared with healthy control subjects. THP‐1 cells expressing mutated M299V revealed almost 10‐fold higher IL‐1β production compared with the wild‐type construct. Conclusion M299V is an activating mutation in NLRP3 resulting in elevated spontaneous caspase 1 activity and IL‐1β levels. The classic CAPS phenotype was lacking in these adult siblings. Whereas one sibling displayed a milder phenotype that has so far responded satisfactorily to oral nonsteroidal antiinflammatory drugs in combination with low‐dose corticosteroids, the inflammatory symptoms in the sibling with the more severe case responded well to IL‐1β blockade. Understanding the pathogenic mechanism underlying such disorders can be helpful for the physician. Our study reinforces the importance of genetic testing and laboratory investigations in combination with careful phenotypic evaluation for the diagnosis of such patients.

Psoriasis is an immune-mediated skin disease driven by the interplay between genetic predisposition and environmental factors. Epigenetic modific | POSTER

Topically applied TH1579 alleviated the psoriatic phenotype in the imiquimod-induced psoriasis mouse model by decreasing CD45⁺, Ly6b⁺, and CD3⁺ cell infiltration and downregulating the expression of the proliferation marker PCNA. Moreover, TH1579 strongly suppressed IL-17 expression in mouse skin, accompanied by reduced infiltration of IL-17-producing γδ-T cells. Furthermore, TH1579 decreased keratinocyte viability and proliferation. Mass spectrometry data analysis revealed the enrichment of proteins associated with nucleotide excision repair and cell cycle regulation. The key cell cycle regulatory protein F-box protein S-phase kinase-associated protein 2 (SKP2) was significantly downregulated, along with the psoriasis-associated proliferation marker WNT5a, identified as a SKP2 downstream target. The downregulation of SKP2 and WNT5a was confirmed in MTH1i-treated mouse skin. Our findings support the topical administration of MTH1i TH1579 as a psoriasis treatment. The therapeutic effects depended on the SKP2/WNT5a pathway, which mediates psoriatic hyperproliferation. This study introduces a conceptually innovative topical treatment for psoriasis patients with mild-to-moderate disease who have limited therapeutic options.

Psoriasis is an immune-mediated systemic skin disorder with a strong genetic predisposition. The gene expression of the psoriasis susceptibility | POSTER