NLRP3 Inflammasome and Inflammation-Related Proteins Expression Characterized in Non-Cultivated Versus Cultivated Peripheral Blood Cells of Patients with Amyotrophic Lateral Sclerosis

Background: Cell and mouse models studies demonstrate NLRP3 inflammasome involvement in amyotrophic lateral sclerosis (ALS) neuroinflammation. Peripheral blood mononuclear cells (PBMCs) are a promising, yet understudied, source of in vivo inflammasome activation biomarkers. Our study reviewed the literature on PBMC-based inflammasome studies of ALS and other neurodegenerative diseases and tested different conditions for PBMC handling to evaluate inflammasome and inflammation-related protein expression in these cells. Methods: Expression of NLRP3 inflammasome components and inflammation-related proteins was analyzed by Real-time qPCR and Western blot in non-cultivated/cultivated PBMCs of 23 ALS patients and 20 Healthy controls. IL-1β and IL-18 levels were measured in plasma and cultivated PBMC supernatants by ELISA. Results: Cultivation of PBMCs decreased expression of inflammasome components and inflammation-related cytokines on the mRNA but not protein level. NLRP3 mRNA expression was significantly higher in ALS-cultivated PBMCs. In both ALS and Healthy controls, IL-18 was detected in plasma, and IL-1β in supernatants of cultivated PBMCs. Conclusions: Our findings suggest that PBMC handling conditions, i.e., cell cultivation, may determine particular parameters associated with NLRP3 inflammasome expression and activation pathway, so they should be carefully selected for PBMC-based studies of inflammasome in neurodegenerative and non-neurological disorders and taken into account when interpreting the study results.