Tripartite-Motif Protein 30 Negatively Regulates NLRP3 Inflammasome Activation by Modulating Reactive Oxygen Species Production

The NLR family, pyrin domain-containing 3 (NLRP3) inflammasome is critical for caspase-1 activation and the proteolytic processing of pro-IL-1β. However, the mechanism that regulates NLRP3 inflammasome activation remains unclear. In this paper, we demonstrate that tripartite-motif protein 30 (TRIM30) negatively regulates NLRP3 inflammasome activation. After stimulation with ATP, an agonist of the NLRP3 inflammasome, knockdown of TRIM30 enhanced caspase-1 activation and increased production of IL-1β in both J774 cells and bone marrow-derived macrophages. Similarly with ATP, knockdown of TRIM30 increased caspase-1 activation and IL-1β production triggered by other NLRP3 inflammasome agonists, including nigericin, monosodium urate, and silica. Production of reactive oxygen species was increased in TRIM30 knockdown cells, and its increase was required for enhanced NLRP3 inflammasome activation, because antioxidant treatment blocked excess IL-1β production. Conversely, overexpression of TRIM30 attenuated reactive oxygen species production and NLRP3 inflammasome activation. Finally, in a crystal-induced NLRP3 inflammasome-dependent peritonitis model, monosodium urate-induced neutrophil flux and IL-1β production was reduced significantly in TRIM30 transgenic mice as compared with that in their nontransgenic littermates. Taken together, our results indicate that TRIM30 is a negative regulator of NLRP3 inflammasome activation and provide insights into the role of TRIM30 in maintaining inflammatory responses.