ASC- and caspase-8-dependent apoptotic pathway diverges from the NLRC4 inflammasome in macrophages

Autor: Sarah K. Kummerfeld, Trinna L. Cuellar, Bettina L. Lee, Michael Reichelt, Benjamin Haley, Nobuhiko Kayagaki, Irma B. Stowe, Kathleen M. Mirrashidi, Colin K. Watanabe
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: Scientific Reports, Vol 8, Iss 1, Pp 1-12 (2018)
Scientific Reports
ISSN: 2045-2322
Popis: The NLRC4 inflammasome recognizes bacterial flagellin and components of the type III secretion apparatus. NLRC4 stimulation leads to caspase-1 activation followed by a rapid lytic cell death known as pyroptosis. NLRC4 is linked to pathogen-free auto-inflammatory diseases, suggesting a role for NLRC4 in sterile inflammation. Here, we show that NLRC4 activates an alternative cell death program morphologically similar to apoptosis in caspase-1-deficient BMDMs. By performing an unbiased genome-wide CRISPR/Cas9 screen with subsequent validation studies in gene-targeted mice, we highlight a critical role for caspase-8 and ASC adaptor in an alternative apoptotic pathway downstream of NLRC4. Furthermore, caspase-1 catalytically dead knock-in (Casp1 C284A KI) BMDMs genetically segregate pyroptosis and apoptosis, and confirm that caspase-1 does not functionally compete with ASC for NLRC4 interactions. We show that NLRC4/caspase-8-mediated apoptotic cells eventually undergo plasma cell membrane damage in vitro, suggesting that this pathway can lead to secondary necrosis. Unexpectedly, we found that DFNA5/GSDME, a member of the pore-forming gasdermin family, is dispensable for the secondary necrosis that follows NLRC4-mediated apoptosis in macrophages. Together, our data confirm the existence of an alternative caspase-8 activation pathway diverging from the NLRC4 inflammasome in primary macrophages.
Databáze: OpenAIRE
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