Gasdermin-D and Caspase-7 are the key Caspase-1/8 substrates downstream of the NAIP5/NLRC4 inflammasome required for restriction of Legionella pneumophila
Fig 3
CASP7 accounts for pore formation and pyroptosis.
Bone marrow-derived macrophages from C57BL/6, Casp1/11–/–, Casp7/1/11–/–, Casp8/1/11/Ripk3–/–and Asc/Casp1/11–/–mice were left uninfected (NI) or infected with wild type L. pneumophila (WT Lp) or flaA mutants at an MOI of 10. (A and B) Pore formation in uninfected (A) and WT Lp-infected (B) macrophages was assessed by Propidium Iodide (PI) uptake. Data are expressed as a percentage of total PI uptake (estimated using Triton-X100). (C) LDH release was assessed 7 hours after infection using CytoTox 96 Non-Radioactive Cytotoxicity Assay. (D) Lysates from C57BL/6, Casp1/11–/–, Casp7/1/11–/–and Nlrc4–/–macrophages were assessed for CASP3 cleavage using anti-Casp3 antibodies. Data are expressed as a percentage of LDH release induced by Triton-X100. Statistical significance was calculated using Student’s t test. *, P<0.05. ns: non-significant. Data are presented for one representative experiment of four (A-B) and two (C-D) experiments performed with similar results.