Caspase-1 Is an Apical Caspase Leading to Caspase-3 Cleavage in the AIM2 Inflammasome Response, Independent of Caspase-8. Issue 2 (19th January 2018)

• Record Type: Journal Article
• Authors: Sagulenko, Vitaliya; Vitak, Nazarii; Vajjhala, Parimala R.; Vince, James E.; Stacey, Katryn J.
• Is Part Of: Journal of molecular biology. Volume 430:Issue 2(2018)
• Page Start: 238
• Page End: 247
• Publication Date: 2018-01-19
• Subjects: AIM2 absent in melanoma 2 -- ASC apoptosis-associated speck-like protein containing a CARD -- BMM bone marrow-derived macrophages -- CARD caspase recruitment domain -- CT-DNA calf thymus DNA -- DED death effector domain -- FCS fetal calf serum -- FSC forward scatter -- GAPDH glyceraldehyde 3-phosphate dehydrogenase -- IL interleukin -- LPS lipopolysaccharide -- NLR Nod-like receptor -- NLRP3 NLR family pyrin domain containing 3 -- PI propidium iodide -- PYD pyrin domain -- siRNA small interfering RNA -- TLR toll-like receptor -- WT wild type; apoptosis -- pyroptosis -- cell death -- caspase-8 knockout -- NLRP3; Molecular biology -- Periodicals; Biology -- Periodicals; Biochemistry -- Periodicals; Bacteriology -- Periodicals; Molecular Biology -- Periodicals; Biochemistry -- Periodicals; Biologie moléculaire -- Périodiques; Biologie -- Périodiques; Biochimie -- Périodiques; Moleculaire biologie; Biochemistry; Biology; Molecular biology; Periodicals; 572.805
• DOI: 10.1016/j.jmb.2017.10.028
• Languages: English
• ISSNs: 0022-2836

Abstract

Abstract: Canonical inflammasomes are multiprotein complexes that can activate both caspase-1 and caspase-8. Caspase-1 drives rapid lysis of cells by pyroptosis and maturation of interleukin (IL)-1β and IL-18. In caspase-1-deficient cells, inflammasome formation still leads to caspase-3 activation and slower apoptotic death, dependent on caspase-8 as an apical caspase. A role for caspase-8 directly upstream of caspase-1 has also been suggested, but here we show that caspase-8-deficient macrophages have no defect in AIM2 inflammasome-mediated caspase-1 activation, pyroptosis, and IL-1β cleavage. In investigating the inflammasome-induced apoptotic pathway, we previously demonstrated that activated caspase-8 is essential for caspase-3 cleavage and apoptosis in caspase-1-deficient cells. However, here we found that AIM2 inflammasome-initiated caspase-3 cleavage was maintained in Ripk3 −/− Casp8 −/− macrophages. Gene knockdown showed that caspase-1 was required for the caspase-3 cleavage. Thus inflammasomes activate a network of caspases that can promote both pyroptotic and apoptotic cell death. In cells where rapid pyroptosis is blocked, delayed inflammasome-dependent cell death could still occur due to both caspase-1- and caspase-8-dependent apoptosis. Initiation of redundant cell death pathways is likely to be a strategy for coping with pathogen interference in death processes. Graphical Abstract: Highlights: Inflammasomes activate a network of caspases to initiate pyroptosis and apoptosis. Caspase-1 and caspase-8 are the inflammasome apical caspases. AIM2 inflammasome activates caspase-1 independent of caspase-8. Caspase-1 and caspase-8 are both upstream of caspase-3 cleavage initiated by AIM2. Redundant death pathways may combat pathogen evasion strategies.