| 2023 |
Activated human caspase-4 (noncanonical inflammasome), but not mouse caspase-11, directly and efficiently cleaves pro-IL-18 at the same tetrapeptide site as caspase-1. Crystal structure of the caspase-4–pro-IL-18 complex revealed a binary (two-site) substrate-recognition mechanism: the catalytic pocket engages the tetrapeptide cleavage site while a unique exosite (also used by caspase-1 and caspase-5) binds a structure formed jointly by the propeptide and post-cleavage-site sequences. Pro-IL-18 harbors autoinhibitory interactions between its propeptide and post-cleavage-site region that prevent IL-18Rα binding; caspase-1/4/5 cleavage induces conformational changes generating two critical receptor-binding sites. |
Crystal structure of caspase-4–pro-IL-18 complex; in vitro cleavage assays; mutagenesis of exosite; bacterial infection cell models |
Nature |
High |
37993714
|
| 1999 |
IL-18 precursor (pro-IL-18) is biologically inactive and requires cleavage by caspase-1 (ICE) to generate the active mature cytokine. The processed mature IL-18 adopts an all-beta-pleated-sheet fold similar to IL-1β. |
In vitro caspase-1 cleavage assay; structural comparison; functional IFN-γ induction assays |
The Journal of allergy and clinical immunology |
High |
9893178
|
| 1999 |
IL-18 signals through a receptor complex composed of IL-18Rα (binding chain, previously identified as IL-1R-related protein/IL-1Rrp) and IL-18Rβ (signaling chain). The complex recruits IL-1R-activating kinase (IRAK) and TRAF-6, which phosphorylates NF-κB-inducing kinase leading to NF-κB activation. |
Receptor subunit identification; signal transduction pathway mapping by biochemical assays |
The Journal of allergy and clinical immunology |
High |
9893178
|
| 1998 |
IL-12 upregulates expression of the IL-18 receptor on IFN-γ-producing cells, explaining the synergism between IL-12 and IL-18 in IFN-γ induction. IL-18 activates NK cells independently of IL-12. |
Receptor expression analysis; cytokine stimulation assays; T cell and NK cell functional assays |
Current opinion in immunology |
Medium |
9638361
|
| 2004 |
In human epithelial cells stably transfected with IL-18Rβ, IL-18 signaling activates p38 MAPK (phosphorylation detectable within 5 min) rather than NF-κB; p38 MAPK inhibition reduced IL-18 activity to background. Unlike IL-1β, IL-18 did not induce IκB degradation or NF-κB reporter activation, explaining the absence of COX-2 induction and failure of IL-18 to cause fever. |
Stable transfection of IL-18Rβ; p38 MAPK phosphorylation assay; NF-κB reporter assay; specific kinase inhibitors; COX-2 mRNA and PGE2 measurements |
Proceedings of the National Academy of Sciences of the United States of America |
High |
15161979
|
| 2025 |
In cancer cells, caspase-3 cleaves IL-18 to generate a 15-kDa 'short IL-18' form distinct from the canonical caspase-1-generated 18-kDa mature form. Short IL-18 is not secreted and does not bind IL-18Rα; instead it translocates to the nucleus, facilitates STAT1 phosphorylation at Ser727 via CDK8, and enhances ISG15 expression and secretion, mobilizing NK cells with increased cytotoxicity against tumors. |
Caspase-3 cleavage assays; nuclear fractionation; IL-18Rα binding assays; CDK8 interaction studies; STAT1 phosphorylation analysis; syngeneic tumor models; mouse genetics |
Nature immunology |
High |
39891018
|
| 2003 |
Bcl6 is a transcriptional repressor of IL-18. Bcl6-binding DNA sequences (IL-18BS) were identified upstream of exon 1 of murine IL-18 and in the promoter of human IL-18. Bcl6 binding to IL-18BS in resting macrophages was demonstrated by gel retardation and chromatin immunoprecipitation; binding diminished after LPS stimulation despite constant Bcl6 protein levels, indicating functional modification of Bcl6 post-stimulation. IL-18BS was required for Bcl6-mediated repression of an IL-18 promoter-luciferase reporter. |
Gel retardation (EMSA); chromatin immunoprecipitation (ChIP); luciferase reporter assay; dominant-negative Bcl6 transfection; Bcl6-/- macrophages |
Journal of immunology (Baltimore, Md. : 1950) |
High |
12817026
|
| 2017 |
Type I IFN (IFNα/β) signaling is essential for IL-18 induction in macrophages: macrophages lacking type I IFN signaling are impaired in IL-18 induction after TLR stimulation. IL-18 expression is sustained after chronic TLR stimulation (escaping endotoxin tolerance) while IL-1β is not, revealing a fundamental regulatory difference. |
TLR stimulation of macrophages; IFN signaling-deficient macrophages; cytokine mRNA and protein measurement; chronic vs. acute TLR stimulation |
Journal of immunology (Baltimore, Md. : 1950) |
Medium |
28468974
|
| 2020 |
IL-18 production from human monocytes requires cooperative TLR and IFNα/β signaling; JAK/STAT inhibition or IFNβ neutralization during LPS stimulation blunted IL-18 expression. This mechanism was confirmed in two MAS mouse models and a patient, where JAK/STAT inhibition reduced IL-18 serum levels. IL-18 (but not IL-1β) expression escapes LPS-induced immunoparalysis. |
Primary human monocyte stimulation; JAK/STAT inhibitors; IFNβ neutralization; MAS mouse models; patient serum analysis |
American journal of respiratory and critical care medicine |
Medium |
31710506
|
| 2015 |
IL-18 signaling in intestinal epithelial cells (IECs) drives colitis and inhibits goblet cell maturation by regulating the transcriptional program instructing goblet cell development. Deletion of Il18 or Il18r1 specifically in IECs protected mice from colitis; deletion of IL-18 negative regulator Il18bp caused severe colitis with goblet cell loss, which was rescued in Il18bp−/−;Il18r(ΔEC) mice, placing colitis severity at the level of IL-18 signaling in IECs. |
Conditional knockout mice (Il18 ΔEC, Il18r1 ΔEC, Il18bp−/−); double-mutant epistasis; goblet cell transcriptional program analysis; DSS colitis model |
Cell |
High |
26638073
|
| 2020 |
Enteric neurons (not immune or epithelial cells) are a source of IL-18 and this neuronal IL-18 is specifically required for homeostatic goblet cell antimicrobial protein (AMP) production. Deletion of IL-18 from enteric neurons alone rendered mice susceptible to invasive Salmonella typhimurium infection. |
Cell-type-specific Il18 deletion; smFISH for IL-18 mRNA in neurons; RNA-seq and single-cell sequencing; bacterial infection model |
Cell |
High |
31923399
|
| 2015 |
NLRP1 inflammasome activation is the upstream regulator that produces IL-18 to prevent obesity and metabolic syndrome. Mice lacking NLRP1 phenocopy IL-18-deficient mice (spontaneous obesity, lipid accumulation); mice with an activating NLRP1 mutation and elevated IL-18 are resistant to diet-induced obesity; fatal cachexia in these mice on high-fat diet is prevented by genetic IL-18 deletion, placing IL-18 downstream of NLRP1. |
NLRP1 KO and activating-mutation knock-in mice; IL-18 KO rescue; high-fat diet metabolic phenotyping; genetic epistasis |
Cell metabolism |
High |
26603191
|
| 2001 |
Human peripheral blood neutrophils constitutively express IL-18Rα and IL-18Rβ and respond directly to IL-18 by releasing cytokines/chemokines (protein-synthesis dependent), upregulating CD11b, inducing granule release, and enhancing respiratory burst. IL-18 administration in vivo promoted neutrophil accumulation; IL-18 neutralization suppressed carrageenan-induced footpad inflammation and reduced tissue MPO and TNF-α. |
Flow cytometry for IL-18R expression; IL-18 stimulation of isolated neutrophils; protein synthesis inhibitor controls; in vivo carrageenan inflammation model; IL-18 neutralizing antibody |
Journal of immunology (Baltimore, Md. : 1950) |
Medium |
11509635
|
| 2003 |
IL-18 promotes neutrophil accumulation in vivo via a TNF-α → leukotriene B4 (LTB4) cascade: IL-18-induced neutrophil recruitment and LTB4 production were blocked by anti-TNF-α antibody or absence of TNFRp55, and by the LTB4 synthesis inhibitor MK-886 or LTB4 receptor antagonist. Human neutrophils activated by IL-18 also produced LTB4. |
Peritoneal neutrophil recruitment assay; TNFRp55-/- mice; LTB4 inhibitor MK-886; LTB4 receptor antagonist; anti-TNF-α neutralization; IL-18-dependent collagen-induced arthritis model |
Journal of immunology (Baltimore, Md. : 1950) |
Medium |
12847274
|
| 2006 |
IL-18 bridges innate and adaptive immunity independently of IL-12 by inducing OX40L on dendritic cells; peptide stimulation induces CD134 (OX40) on antigen-specific T cells. CD134 blockade inhibited T cell effector expansion and reduced IFN-γ super-producers by 12-fold. The effect required host-derived IFN-γ but not NK cells or IL-12. |
In vivo mouse immunization; CD134 blockade; IFN-γ−/− mice; NK cell depletion; IL-12 blockade; T cell clonal expansion assays |
Journal of immunology (Baltimore, Md. : 1950) |
Medium |
16785519
|
| 2013 |
IL-18 and IL-1β are independently regulated downstream of NLRP3 inflammasome activation: ROS production (via caspase-11) is required for IL-1β secretion but not IL-18 secretion. Caspase-11-deficient DCs failed to secrete IL-1β in response to Listeria p60 but retained full IL-18 secretion. |
NLRP3 inflammasome activation with Listeria p60; ROS inhibitors; caspase-11-deficient DCs; ELISA for IL-1β and IL-18 |
PloS one |
Medium |
23028835
|
| 2012 |
In IL-18-deficient mice with CAPS-associated NLRP3 mutations, IL-18 receptor deletion provided greater phenotypic rescue (abolished skin and visceral disease, normalized serum cytokines) than IL-1R deletion at early stages, demonstrating distinct roles for IL-18 vs. IL-1β in CAPS pathology. Persistent inflammation in double-cytokine receptor KO CAPS mice implicated caspase-1-mediated pyroptosis as an additional pathway. |
CAPS mouse models bred onto Il18r-null and Il1r-null backgrounds; phenotypic and cytokine analyses; genetic epistasis |
The Journal of clinical investigation |
High |
24084736
|
| 2001 |
IL-18BP is a high-affinity naturally occurring binding protein that neutralizes IL-18 in the fluid phase, balancing its biological activity. Human IL-18BP and orthopoxvirus homologs bind both human and murine IL-18 with measurable dissociation constants (viral proteins show 12–50-fold lower Kd for murine vs. human IL-18); binding inhibits IFN-γ induction by IL-18. |
Surface plasmon resonance (SPR/Biacore) affinity measurements; IFN-γ induction bioassay inhibition |
Virology |
High |
11145885
|
| 2018 |
Inflammasome-dependent IL-18 (not IL-1β) is the critical upstream regulator of chemokine expression and macrophage infiltration in the myocardium upon acute β1-AR/ROS signaling by isoproterenol. Genetic deletion of IL-18 or NLRP3 significantly attenuated chemokine expression and macrophage infiltration. IL-18 neutralizing antibodies selectively abated proinflammatory cytokines but not growth factors, and early IL-18 blockade prevented cardiac fibrosis. |
Cytokine array; IL-18−/− and NLRP3−/− mice; IL-18 neutralizing antibodies; isoproterenol model; histology for fibrosis and macrophage infiltration |
European heart journal |
Medium |
28549109
|
| 2009 |
IL-18 induces osteopontin (OPN) expression in cardiac fibroblasts via IRF1 transcription factor, leading to interstitial fibrosis and diastolic dysfunction. Blockade of the IL-18 receptor abolished conditioned-medium-induced OPN upregulation; IRF1 mutation or siRNA reduced IL-18 and OPN in cardiac fibroblasts; IRF1-mutant mice showed downregulated IL-18/OPN and reduced fibrosis under pressure overload. |
Recombinant IL-18 treatment of cardiac fibroblasts; IL-18R neutralizing antibody; IRF1 siRNA knockdown; IRF1-mutant mice; pressure/volume overload models; Western blot/qPCR |
American journal of physiology. Heart and circulatory physiology |
Medium |
19429811
|
| 2013 |
IL-18 induces profibrotic changes in renal tubular epithelial cells (HK-2) via STAT3 activation: IL-18 increased phospho-STAT3, SOCS3, α-SMA, collagen III expression and TEC apoptosis in vitro, effects significantly diminished by the STAT3 inhibitor S3I-201. In vivo, IL-18 neutralization (via IL-18BP transgene) reduced p-STAT3 after ureteral obstruction. |
IL-18 stimulation of HK-2 cells; STAT3 inhibitor S3I-201; Western blotting for p-STAT3; IL-18BP transgenic mice with ureteral obstruction |
American journal of physiology. Renal physiology |
Medium |
23904224
|
| 2009 |
IL-18 downregulates type I and III collagen production in human dermal fibroblasts through Ets-1 transcription factor and ERK pathway activation: ERK phosphorylation occurred within 10 min of IL-18 treatment; ERK inhibitor PD98059 blocked IL-18's inhibitory effect on collagen; Ets-1 siRNA knockdown abolished IL-18-regulated collagen suppression. |
ERK phosphorylation assay; PD98059 ERK inhibitor; Ets-1 siRNA; collagen gene expression and protein measurement; primary dermal fibroblast and SSc fibroblast cultures |
The Journal of investigative dermatology |
Medium |
19865096
|
| 2006 |
IL-18 acts synergistically with IL-15 to stimulate NK cell proliferation in vitro through direct stimulation of NK cells rather than via an intermediary cell type (shown using an NK cell line). |
In vitro NK cell proliferation assay; NK cell line (excluding indirect signaling); IL-18 + IL-15 co-stimulation |
Cytokine |
Medium |
17052916
|
| 2017 |
IL-18 drives ILC3 proliferation and IL-22 production via NF-κB: the p65 NF-κB subunit binds the proximal IL22 promoter and promotes transcriptional activity downstream of IL-18 signaling. CD11c+ dendritic cells expressing IL-18 were found adjacent to ILC3s in human tonsils in situ. |
IL-18 stimulation of human ILC3s; NF-κB pathway analysis; p65 promoter binding (ChIP/reporter); in situ human tonsil immunostaining |
Journal of immunology (Baltimore, Md. : 1950) |
Medium |
28842466
|
| 2013 |
CD8+ T cell-derived granzyme B cleaves keratinocyte pro-IL-18 into its active form; co-culture of granzyme B+/caspase-1− CD8+ T cells with IFN-γ-treated HaCaT keratinocytes resulted in GrB transfer into keratinocytes and increased mature IL-18 in culture supernatant. |
CD8+ T cell/HaCaT keratinocyte co-culture; flow cytometry for intracellular GrB; ELISA for mature IL-18; GrB+/caspase-1− T cell validation by PCR |
Archives of dermatological research |
Medium |
23820889
|
| 2001 |
IFN-γ induces expression and secretion of IL-18 binding protein (IL-18BPa) from human colon carcinoma/epithelial cells (DLD-1, LoVo, Caco-2, HCT116) and keratinocytes (HaCaT); secreted IL-18BPa significantly impaired IL-18/IL-12-stimulated IFN-γ release from PBMC. Sodium butyrate suppressed IFN-γ-induced IL-18BPa but not IL-18 expression, suggesting context-dependent modulation. |
IFN-γ stimulation; IL-18BPa mRNA and protein measurement; functional IFN-γ production bioassay; sodium butyrate treatment; organ cultures from intestinal biopsies |
Journal of immunology (Baltimore, Md. : 1950) |
Medium |
11739524
|
| 2024 |
In pancreatic cancer cells, GFPT2-mediated O-GlcNAcylation promotes nuclear translocation of YBX1, which then functions as a transcription factor to promote IL-18 transcription, linking HBP metabolism to IL-18-dependent immune microenvironment regulation. |
Co-IP; protein mass spectrometry identifying YBX1 O-GlcNAcylation; transcriptional reporter assays; GFPT2 KO/knockdown; cellular proteomics |
Cell death & disease |
Medium |
38575607
|
| 2024 |
IL-18 stimulation activates SLC12A3 (NCC) in macrophages, leading to sodium influx, mitochondrial DNA release, and STING activation, reprogramming macrophages from glycolysis to fatty acid oxidation (FAO). This metabolic switch is maintained by a bistable feedback loop involving macrophage-derived 2'3'-cGAMP and epithelial IL-18, encoding durable intestinal immune tolerance. |
Metabolic flux analysis; SLC12A3 inhibition/KO; STING KO; mitochondrial DNA measurement; cGAMP measurement; intestinal tolerance models |
Immunity |
Medium |
38906145
|
| 2011 |
IL-18 produced by tumor cells promotes the development of NK-cell-controlled metastases in a PD-1-dependent manner; IL-18 upregulates PD-1 on mature NK cells in lymphoid organs of tumor-bearing mice. RNAi knockdown of IL-18 in tumors or systemic depletion by IL-18BP stimulated NK cell-dependent immunosurveillance. |
Tumor-derived IL-18 knockdown (RNAi); IL-18BP depletion; PD-1 expression analysis on NK cells; PD-1-deficient mice; metastasis models |
Cancer research |
Medium |
21724589
|
| 2020 |
IL-18BP is frequently upregulated in tumors and limits IL-18 anti-tumor activity. A directed-evolution-engineered 'decoy-resistant' IL-18 (DR-18) maintains IL-18R signaling but is impervious to IL-18BP inhibition; DR-18 promoted poly-functional effector CD8+ T cells, reduced TOX+ exhausted CD8+ T cells, expanded TCF1+ stem-like CD8+ T cells, and enhanced NK cell activity in anti-PD-1-resistant tumors lacking MHC-I. |
Directed evolution; IL-18BP binding assays; mouse tumor models; flow cytometry for T cell subsets; comparison with wild-type IL-18 |
Nature |
High |
32581358
|
| 2016 |
IL-18-mediated lethality in neonatal sepsis requires IL-1R1 signaling (not adaptive immunity) and depends on IL-17A produced by intestinal γδT cells and Ly6G+ myeloid cells. IL-18 administration increased IL-17A production, and blocking IL-17A reduced IL-18-potentiated mortality in both neonatal sepsis and endotoxemia, placing IL-17A as an effector downstream of IL-18. |
IL-18−/− neonatal mice; IL-1R1 KO; γδT cell analysis; IL-17A blockade; genome-wide blood mRNA analysis from septic neonates |
Proceedings of the National Academy of Sciences of the United States of America |
Medium |
27114524
|
| 2007 |
IL-18 is constitutively expressed specifically in the intercalated cells of the late distal convoluted tubule, connecting tubule, and collecting duct of the healthy human kidney. These same cells also express caspase-1 and P2X7 receptor (both required for IL-18 processing and secretion), establishing the cellular machinery for IL-18 activation at this site. |
In situ hybridization; immunohistochemistry with cell-type markers (calbindin-D28k, aquaporin-2, vacuolar H+-ATPase); confocal microscopy; Western blot; PCR |
Kidney international |
Medium |
17687255
|
| 2006 |
IL-18 reduces UV-induced DNA damage in keratinocytes and prevents photoimmunosuppression via promotion of DNA repair; the effect was absent in Xpa-knockout (DNA repair-deficient) mice, demonstrating dependence on nucleotide excision repair. Unlike IL-12, IL-18 did not break UV-induced immunotolerance mediated by regulatory T cells. |
UV irradiation of mice; IL-18 injection; apoptosis and DNA damage immunohistochemistry; Xpa-KO mice; contact hypersensitivity readout |
Journal of immunology (Baltimore, Md. : 1950) |
Medium |
16493047
|
| 2018 |
IL-18 reduces voltage-gated potassium channel (Ito current) expression in cardiomyocytes, causing electrical remodeling and ventricular tachycardia. Sustained IL-18 inhibition with IL-18BP in SCD mice decreased cardiac fibrosis, NF-κB phosphorylation, improved diastolic function, and attenuated VT; recombinant IL-18 administered to isolated hearts triggered VT from the right ventricle. |
SCD humanized mouse model; IL-18BP treatment; patch-clamp recording of Ito; recombinant IL-18 in isolated hearts; NF-κB phosphorylation assay; echocardiography |
Blood |
Medium |
33181835
|
| 2006 |
IL-18 enhances thrombospondin-1 (TSP-1) production in human gastric cancer cells in a dose- and time-dependent manner via JNK pathway activation: SP600125 (JNK inhibitor) blocked IL-18-enhanced TSP-1 expression; IL-18 increased phosphorylated JNK as detected by Western blot. |
RT-PCR; ELISA; JNK inhibitor SP600125; phospho-JNK Western blot |
Biochemical and biophysical research communications |
Low |
16650813
|
| 2018 |
Unopposed IL-18 signaling (in IL-18BP-deficient mice) drives severe MAS upon TLR9 stimulation, with IL-18 acting upstream of IFN-γ. Blocking IL-18 receptor signaling attenuated MAS severity and IFN-γ responses; blocking IFN-γ had comparable effects, establishing the IL-18→IFN-γ axis in MAS pathogenesis. |
IL-18BP-KO mice; TLR9/CpG stimulation; IL-18R blockade; IFN-γ blockade; serum cytokine and IFN-γ signature gene analysis |
Blood |
Medium |
29295842
|
| 2002 |
Langerhans cell-derived IL-18, processed by caspase-1, contributes to contact hypersensitivity initiation: caspase-1−/− mice had impaired IFN-γ production from LN cells that was restored by exogenous IL-18; CHS responses were inhibited by anti-IL-18 antibody and in caspase-1−/− mice; migratory hapten-modified LC in LN expressed high IL-18 mRNA and secreted functional IL-18. |
Caspase-1-KO mice; exogenous IL-18 rescue; anti-IL-18 neutralizing antibody; CHS in vivo model; mRNA expression in LN cells |
Journal of immunology (Baltimore, Md. : 1950) |
Medium |
11907086
|
| 2019 |
Choline uptake via CTL1 transporter in macrophages supports NLRP3 inflammasome activation and IL-18 production; inhibition of CTL1 or choline kinase altered mitochondrial lipid profile, attenuated mitochondrial ATP synthesis, and activated AMPK, which stimulates DRP1-mediated mitophagy to terminate NLRP3 inflammasome activation. |
CTL1 inhibition/knockdown; choline kinase inhibitors; mitochondrial lipid profiling; AMPK activation assay; DRP1 mitochondrial recruitment; mitophagy assay; IL-18 ELISA |
Cell metabolism |
Medium |
30982734
|