Effect of Dopamine on NLRP3 Inflammasome Activity and Thiol Metabolites in Human THP-1 Macrophages

Effect of Dopamine on NLRP3 Inflammasome Activity and Thiol Metabolites in Human THP-1 Macrophages

Alvin Sherman Library

Neuroinflammation plays an important role in aging and neurological disorders across the lifespan and the NLRP3 inflammasome has been closely linked to the progression of neurodegenerative diseases and is a potential target for therapy. The neurotransmitter dopamine regulates production of inflammatory cytokines in an age-dependent manner and in neurons dopamine is stored in a complex with ATP and both are released during neuronal activity. ATP promotes NLRP3 inflammasome activity via the P2X7 receptor. However, the combined influence of dopamine and ATP on inflammasome activity has not been previously investigated. The goal of this study was to examine lipopolysaccharide (LPS)-induced NLRP3 inflammasome activity in cultured THP-1 human leukemia monocyte cells following exposure to ATP and dopamine or their combination. Levels of the proinflammatory cytokine IL-1B were assessed using an ELISA assay and HPLC LC-MS/MS was used to assess levels of thiol metabolites, including methionine, cysteine, and glutathione. Basal IL-1B levels were higher in low-passage number THP1 cells vs. high-passage cells. LPS significantly increased IL-1B levels, but dopamine did not affect basal or LPS-induced IL-1B levels in either low or high-passage cells. However, dopamine significantly increased ATP-induced IL-1B levels in low-passage number THP-1 cells, but not in high-passage cells. Dopamine significantly increased cysteine and glutathione levels in the presence of LPS in low-passage cells, but not in high-passage cells. These preliminary findings suggest that dopamine may regulate the ATP-induced NLRP3 inflammasome response in low-passage THP-1 macrophages.