A genome-wide screen uncovers broad roles for mitochondrial nucleoside diphosphate kinases in inflammasome activation

• Published in: Science signaling 2021-08, Vol.14 (694)
• Main Authors: Ernst, Orna, Sun, Jing, Lin, Bin, Banoth, Balaji, Dorrington, Michael G., Liang, Jonathan, Schwarz, Benjamin, Stromberg, Kaitlin, Katz, Samuel, Vayttaden, Sharat J., Bradfield, Clinton J., Slepushkina, Nadia, Rice, Christopher M., Buehler, Eugen, Khillan, Jaspal S., McVicar, Daniel W., Bosio, Catharine M., Bryant, Clare E., Sutterwala, Fayyaz S., Martin, Scott, Lal-Nag, Madhu, Fraser, Iain D.C.
• Format: Article
• Language: English
• ISSN: 1945-0877; 1937-9145
• DOI: 10.1126/scisignal.abe0387

Non-canonical inflammasome activation by cytosolic LPS is a critical component of the host response to Gram-negative bacterial infection, however we lack a comprehensive understanding of the cellular processes that control this pathway. Using a genome-scale arrayed siRNA screen to discover inflammasome regulators in macrophages, we identified the mitochondrial Nme4 gene, which codes for the multi-functional nucleoside diphosphate kinase D (NDPK-D), as a regulator of both non-canonical and canonical inflammasomes. We show that Nme4 is required for both mitochondrial DNA synthesis and cardiolipin exposure on the mitochondrial surface in response to priming signals, leading to broad inflammasome activation defects in Nme4 -deficient cells. In addition, Nme4 is required for TRAF6 mitochondrial recruitment and ROS production, which supports the large-scale TLR-induced gene program via Nme4 -dependent TLR signaling responses. Nme4 knock-out mice are protected from endotoxin-induced shock, consistent with attenuated ROS production and glycolytic commitment. Our findings suggest that in response to microbial challenge, Nme4 -dependent TRAF6 mitochondrial recruitment triggers an energetic fitness checkpoint required to engage and support the transcriptional gene program necessary to support inflammasome activation.