Cell-based <i>in vitro</i> hemoassay for evaluation of NLRP3-inflammasome activity

Abstract

Currently, gouty arthritis is considered as a polygenic multifactorial autoinflammatory disease caused by activation of the NOD (nucleotide-binding domain) -like protein receptor 3 inflammasome NLRP3. The two cytokines IL-1β and IL-18 are considered important biomarkers of NLRP3 inflammasome activation. However, usually the concentration of IL-1β in donor sera is extremely low and found to be at the limit of detection level (1-3 pg/ml), while the concentration of circulating cytokine IL-18 in the sera of individual donors varies greatly. This results in difficulty using these biomarkers in the diagnosis of autoinflammatory diseases. We hypothesized that the patient’s blood cells which were sensitized in vivo to the presence of specific factors characteristic of autoinflammatory diseases, in particular, gouty arthritis, would produce increased amounts of the inflammasome-regulated cytokines compared to blood cells obtained from healthy donors. A comparison of the IL-18 cytokine in healthy donors and patients with gouty arthritis was carried out using 2 methods: a) by traditional analysis of the level of serum circulated IL-18 and b) by using a cell-based Hemoassay in vitro developed at the research institute “Biotech” SamGMU. The comparative analysis demonstrated the advantages of using an in vitro cell-based Hemoassay to assess the IL-18 cytokine status of patients. Serum IL-18 values varied widely and showed no significant difference between donors and patients with gouty arthritis. Using the developed cell-based Hemoassay in vitro, significant quantitative differences in the production of the inflammatory cytokine IL-18 produced by blood cells of potentially healthy donors and patients with gouty arthritis were detected. Blood cells of individual patients, sensitized in vivo with specific factors characteristic of gouty arthritis, produce increased concentrations of IL-18 in the cell growth medium in vitro compared to cells from healthy donors. Thus, the in vitro cell-based Hemoassay can be used for a more accurate assessment of the cytokine status of patients.

Keywords

• cell-based assay
• il-18
• inflammasome nlrp3
• gouty arthritis
• serum
• uric acid
• cytokines