ASC Directs NF-κB Activation by Regulating Receptor Interacting Protein-2 (RIP2) Caspase-1 Interactions

Sarkar, Anasuya; Duncan, Michelle; Hart, Judy; Hertlein, Erin; Guttridge, Denis C.; Wewers, Mark D.

doi:10.4049/jimmunol.176.8.4979

Cited by 112 publications

(111 citation statements)

References 49 publications

(52 reference statements)

Supporting

Mentioning

105

Contrasting

Unclassified

Order By: Relevance

“…Our findings may explain the profound phenotype of caspase-1-deficient mice, which, unlike IL-1␤ and IL-18 knockout (KO) mice, and as recently shown in IL-1␤/IL-18 double KO mice (26), are completely resistant to the effects of LPS (27)(28)(29) and are also highly susceptible to infection with pathogens such as Escherichia coli (30,31). Similar to our study, others have shown defects in LPS responses in caspase-1-deficient macrophages such as induction of TNF, IL-6, and IL-1␣ (20,29,31). TNF production in response to LPS was not affected by a neutralizing antibody to IL-18 or in IL-1␤-deficient mice (32,33).…”

Section: Discussionsupporting

confidence: 77%

See 1 more Smart Citation

NF-κB activation by the Toll-IL-1 receptor domain protein MyD88 adapter-like is regulated by caspase-1

Miggin

Pålsson-McDermott²,

Dunne³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

114

View full text Add to dashboard Cite

The authors note that Fig. 3 appeared incorrectly. Panel B (Top) depicting the time course of NF-κB activation in wild type and caspase-1 deficient peritoneal macrophages is not the same version as the authors submitted originally to PNAS. A correct version including vertical rules to indicate splicing is shown below. Regarding panel C, during the preparation of the manuscript, we inadvertently repeated a set of p38 blots corresponding to p-p38 Western blots. The correct p38 Western blots are shown below. The findings of the paper have not been affected by the error and the authors apologize to the editors and readers. The corrected figure and its legend appear below. . Caspase-1 is required for Mal to signal. (A) (Upper) U373 cells were transfected with a 5x NF-κB reporter gene plasmid. Cells were left untreated or pretreated with YVAD-Cmk (100 μM) or IL-1 receptor antagonist (1 μg/ml) for 1 h. Thereafter, cells were untreated or incubated with LPS (1 μg/ml) or IL-1 (100 ng/ml) for 6 h. Shown is the mean relative stimulation of luciferase activity ± SD for a representative experiment from three separate experiments. (Lower) THP-1 cells were left untreated or pretreated with YVAD-Cmk (100 μM) or IETD-Fmk (50 μM) for 1 h followed by treatment with Pam 3 Cys (1 μg/ml) or IL-1 (1 μg/ml) for 0-120 min. Activation of p38 was analyzed by using an anti-phospho-p38-specific antibody. (B) (Top) Time course of NF-κB activation in wild-type and caspase-1-deficient peritoneal macrophages stimulated with LPS (10 ng/ml), Malp-2 (10 nM), and R848 (10 μM) as detected by EMSA. (Middle) Supershift assay was performed by using an anti-p65 antibody for 1 h before analysis by EMSA. Protein:DNA complexes are shown. (Bottom) Wild-type and caspase-1-deficient murine embryonic fibroblasts were treated with LPS (100 ng/ml), lipid A (100 ng/ml), or Malp-2 (10 nM) as indicated, followed by immunoblot analysis of the cell lysates with antibodies directed against IκBα or β-actin. (C) Time course of p38 activation in wild-type and caspase-1-deficient peritoneal macrophages stimulated with LPS (100 ng/ml), Malp-2 (10 nM), and IL-1 (1 μg/ml) analyzed by immunoblotting with phospho-p38-specific antibodies. Total p38 levels are also shown. (D) Time course of p38 activation in wild-type and caspase-1-deficient peritoneal murine embryonic fibroblasts stimulated with LPS (100 ng/ml) or Malp-2 analyzed by immunoblotting with phospho-p38-specific antibodies. Total p38 levels are also shown.

show abstract

Section: Discussionsupporting

confidence: 77%

“…4C Right, lane 3). THP-1 cells display caspase-1 activation in response to LPS alone and thus do not require costimulation with ATP (19,20). In mouse macrophages, treatment with LPS led to the appearance of an additional form of Mal that was 2.5 kDa smaller in molecular mass than the major form of Mal (Fig.…”

Section: Resultsmentioning

confidence: 99%

NF-κB activation by the Toll-IL-1 receptor domain protein MyD88 adapter-like is regulated by caspase-1

Miggin

Pålsson-McDermott²,

Dunne³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

114

View full text Add to dashboard Cite

show abstract

“…29 Consistent with a role for ASC as an inhibitor for caspase-1/RIP2-induced NF-kB activation, siRNA-induced knockdown of ASC in THP-1 cells leads to higher NF-kB activation levels, while caspase-1 activation and release of mature IL-1b are diminished. 29 Altogether, these results suggest that caspase-1 may contribute to pro-IL-1b processing through its enzymatic activity, while its interaction with RIP2 induces NF-kB activation. Furthermore, ASC may function as a switch that directs caspase-1 away from RIP2-mediated NF-kB activation towards the maturation of pro-IL-1b in the inflammasome complexes.…”

mentioning

confidence: 64%

“…27 Recently, this caspase-1/RIP2 interaction was shown to be modulated by the adaptor molecule ASC, which also interacts with caspase-1 via its CARD. 29 ASC interferes with the caspase-1/RIP2 interaction and inhibits the subsequent NF-kB activation in a dose-dependent fashion, while stimulating caspase-1-dependent pro-IL-1b maturation. 29 Consistent with a role for ASC as an inhibitor for caspase-1/RIP2-induced NF-kB activation, siRNA-induced knockdown of ASC in THP-1 cells leads to higher NF-kB activation levels, while caspase-1 activation and release of mature IL-1b are diminished.…”

mentioning

confidence: 99%

“…29 ASC interferes with the caspase-1/RIP2 interaction and inhibits the subsequent NF-kB activation in a dose-dependent fashion, while stimulating caspase-1-dependent pro-IL-1b maturation. 29 Consistent with a role for ASC as an inhibitor for caspase-1/RIP2-induced NF-kB activation, siRNA-induced knockdown of ASC in THP-1 cells leads to higher NF-kB activation levels, while caspase-1 activation and release of mature IL-1b are diminished. 29 Altogether, these results suggest that caspase-1 may contribute to pro-IL-1b processing through its enzymatic activity, while its interaction with RIP2 induces NF-kB activation.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Caspases in cell survival, proliferation and differentiation

et al. 2006

View full text Add to dashboard Cite

Caspases, a family of evolutionarily, conserved cysteinyl proteases, mediate both apoptosis and inflammation through aspartate-specific cleavage of a wide number of cellular substrates. Most substrates of apoptotic caspases have been conotated with cellular dismantling, while inflammatory caspases mediate the proteolytic activation of inflammatory cytokines. Through detailed functional analysis of conditional caspase-deficient mice or derived cells, caspase biology has been extended to cellular responses such as cell differentiation, proliferation and NF-jB activation. Here, we discuss recent data indicating that nonapoptotic functions of caspases involve proteolysis exerted by their catalytic domains as well as non-proteolytic functions exerted by their prodomains. Homotypic oligomerization motifs in the latter mediate the recruitment of adaptors and effectors that modulate NF-jB activation. The non-apoptotic functions of caspases suggest that they may become activated independently of -or without -inducing an apoptotic cascade. Moreover, the existence of non-catalytic caspase-like molecules such as human caspase-12, c-FLIP and CARD-only proteins further supports the non-proteolytic functions of caspases in the regulation of cell survival, proliferation, differentiation and inflammation. Cell Death and Differentiation (2007) 14, 44-55. doi:10.1038/sj.cdd.4402047; published online 20 October 2006 Caspases are an evolutionarily conserved family of aspartatespecific cystein-dependent proteases with central functions in apoptotic and inflammatory signalling pathways.1 Certain caspases have large prodomains that contain related homotypic oligomerization motifs such as the caspase recruitment domain (CARD,

show abstract

Critical role for Ipaf in Pseudomonas aeruginosa‐induced caspase‐1 activation

et al. 2007

View full text Add to dashboard Cite

Pseudomonas aeruginosa is an opportunistic Gram-negative human pathogen that is responsible for a broad range of infections in individuals with a variety of predisposing conditions. After infection, P. aeruginosa induces a marked inflammatory response in the host. However the mechanisms involved in bacterium recognition and induction of immune responses are poorly understood. Here we report that the Nod-like receptor family member Ipaf is required for optimal bacterial clearance in an in vivo model of P. aeruginosa lung infection. Further analysis showed that bacterial flagellin was essential for caspase-1 and IL-1b and this activity depended on Ipaf and the adaptor ASC but not TLR5. Notably, P. aeruginosa induced macrophage cell death and this event relied on flagellin and Ipaf but not on ASC. Analysis of Pseudomonas mutants revealed that different amino acid residues of flagellin were critical for sensing by Ipaf and TLR5. Finally, activation of caspase-1 and IL-1b secretion by P. aeruginosa required a functional type III secretion system, but not the effector molecules ExoS, ExoT and ExoY. These results provide new insight into the interaction of P. aeruginosa with host macrophages and suggest that distinct regions of flagellin are sensed by Ipaf and TLR5. Introduction IL-1b plays an important role in the induction of immune responses and in the development of inflammatory disease, fever and septic shock [1]. In response to proinflammatory stimuli including pathogenic bacteria, the IL-1b precursor is induced in monocytes and macrophages and processed into the biologically active IL-1b molecule by caspase-1 [2][3][4][5]. The protease caspase-1 is expressed in monocytes/macrophages as an inactive zymogen that is activated by self cleavage in large multi-protein complexes named 'inflammasomes' [6].The mechanism responsible for activation of caspase-1 in response to microbial stimuli has remained poorly understood. Recent studies have revealed members of the Nod-like receptor (NLR) family as critical components of the inflammasomes by linking microbial sensing to caspase-1 activation [7,8]. For example, Ipaf, an NLR family member and the adaptor ASC have been implicated in activation of caspase-1 in response to Salmonella and Legionella through the cytosolic sensing of flagellin [7,9,10]. Notably, flagellin is also recognized by TLR5 [11]. However, it is unclear whether Ipaf and TLR5 sense identical or distinct regions of flagellin. Similarly, Cryopyrin/Nalp3 is critical for caspase-1 activation and secretion of IL-1b and IL-18 in response to microbial RNA, synthetic purine-like compounds and endogenous urate crystals [12][13][14]. In addition, Cryopyrin regulates caspase-1 activation triggered by exogenous ATP or pore-forming toxins in macrophages stimulated with several TLR agonists [15,16]. Pseudomonas aeruginosa is a flagellated opportunistic Gram-negative human pathogen that is responsible for a broad range of infections in individuals with a variety of predisposing conditions including cystic fibrosis, immu...

show abstract

ASC Directs NF-κB Activation by Regulating Receptor Interacting Protein-2 (RIP2) Caspase-1 Interactions

Cited by 112 publications

References 49 publications

NF-κB activation by the Toll-IL-1 receptor domain protein MyD88 adapter-like is regulated by caspase-1

NF-κB activation by the Toll-IL-1 receptor domain protein MyD88 adapter-like is regulated by caspase-1

Caspases in cell survival, proliferation and differentiation

Critical role for Ipaf in Pseudomonas aeruginosa‐induced caspase‐1 activation

Contact Info

Product

Resources

About