Interleukin-18 gene promoter polymorphisms and recurrent spontaneous abortion

Background: IL-18 is a multifunctional cytokine capable of inducing either Th1 or Th2 polarization depending on the immunologic milieu. IL-18 is detected at the materno-fetal interface very soon in early pregnancy. Two polymorphisms in the promoter region of the IL-18 gene at positions of -607 and -137 appear to have functional impacts. Objective: This study attempts to evaluate the frequency of these two polymorphisms in the IL-18 gene promoter in patients with recurrent spontaneous abortion (RSA) and normal pregnant women. Subjects and methods: One hundred and two RSA patients and 103 healthy pregnant women were enrolled in this study. Single nucleotide polymorphisms of the IL-18 gene at positions -607 (C/A) and -137 (G/C) were analyzed by the sequence-specific PCR method. Results: There was no significant association between the allele, genotype, and haplotype frequencies of the two single nucleotide polymorphisms (SNPs) in the IL-18 gene promoter and RSA. Conclusion: The results of this study showed that IL-18 gene promoter polymorphisms at positions -607 and -137 did not confer susceptibility to RSA in southern Iranian patients. © 2006 Elsevier Ireland Ltd. All rights reserved

Interleukin-18 mediates cardiac dysfunction induced by western diet independent of obesity and hyperglycemia in the mouse

Obesity and diabetes are independent risk factors for heart failure and are associated with the consumption of diet rich in saturated fat and sugar, Western diet (WD), known to induce cardiac dysfunction in the mouse through incompletely characterized inflammatory mechanisms. We hypothesized that the detrimental cardiac effects of WD are mediated by interleukin-18 (IL-18), pro-inflammatory cytokine linked to cardiac dysfunction. C57BL/6J wild-type male mice and IL-18 knockout male mice were fed high-saturated fat and high-sugar diet for 8 weeks. We measured food intake, body weight and fasting glycemia. We assessed left ventricular (LV) systolic and diastolic function by Doppler echocardiography and cardiac catheterization. In wild-type mice, WD induced a significant increase in isovolumetric relaxation time, myocardial performance index and left ventricular end-diastolic pressure, reflecting an impairment in diastolic function, paired with a mild reduction in LV ejection fraction. IL-18 KO mice had higher food intake and greater increase in body weight without significant differences in hyperglycemia. Despite displaying greater obesity, IL-18 knockout mice fed with WD for 8 weeks had preserved cardiac diastolic function and higher left ventricular ejection fraction. IL-18 mediates diet-induced cardiac dysfunction, independent of food intake and obesity, thus highlighting a disconnect between the metabolic and cardiac effects of IL-18

Interleukin-18 enhances vascular calcification and osteogenic differentiation of vascular smooth muscle cells through TRPM7 channel activation

Objective—Vascular calcification (VC) is an important predictor of cardiovascular morbidity and mortality. Osteogenic differentiation of vascular smooth muscle cells (VSMCs) is a key mechanism of VC. Recent studies show that IL-18 (interleukin-18) favors VC while TRPM7 (transient receptor potential melastatin 7) channel upregulation inhibits VC. However, the relationship between IL-18 and TRPM7 is unclear. We questioned whether IL-18 enhances VC and osteogenic differentiation of VSMCs through TRPM7 channel activation. Approach and Results—Coronary artery calcification and serum IL-18 were measured in patients by computed tomographic scanning and enzyme-linked immunosorbent assay, respectively. Primary rat VSMCs calcification were induced by high inorganic phosphate and exposed to IL-18. VSMCs were also treated with TRPM7 antagonist 2-aminoethoxy-diphenylborate or TRPM7 small interfering RNA to block TRPM7 channel activity and expression. TRPM7 currents were recorded by patch-clamp. Human studies showed that serum IL-18 levels were positively associated with coronary artery calcium scores (r=0.91; P<0.001). In VSMCs, IL-18 significantly decreased expression of contractile markers α-smooth muscle actin, smooth muscle 22 α, and increased calcium deposition, alkaline phosphatase activity, and expression of osteogenic differentiation markers bone morphogenetic protein-2, Runx2, and osteocalcin (P<0.05). IL-18 increased TRPM7 expression through ERK1/2 signaling activation, and TRPM7 currents were augmented by IL-18 treatment. Inhibition of TRPM7 channel by 2-aminoethoxy-diphenylborate or TRPM7 small interfering RNA prevented IL-18–enhanced osteogenic differentiation and VSMCs calcification. Conclusions—These findings suggest that coronary artery calcification is associated with increased IL-18 levels. IL-18 enhances VSMCs osteogenic differentiation and subsequent VC induced by β-glycerophosphate via TRPM7 channel activation. Accordingly, IL-18 may contribute to VC in proinflammatory conditions

De-novo design of complementary (antisense) peptide mini-receptor inhibitor of interleukin 18 (IL-18).

Complementary (antisense) peptide mini-receptor inhibitors are complementary peptides designed to be receptor-surrogates that act by binding to selected surface features of biologically important proteins thereby inhibiting protein-cognate receptor interactions and subsequent biological effects. Previously, we described a complementary peptide mini-receptor inhibitor of interleukin-1beta (IL-1beta) that was designed to bind to an external surface loop (beta-bulge) of IL-1beta (Boraschi loop) clearly identified in the X-ray crystal structure of this cytokine. Here, we report the de-novo design and rational development of a complementary peptide mini-receptor inhibitor of cytokine interleukin-18 (IL-18), a protein for which there is no known X-ray crystal structure. Using sequence homology comparisons with IL-1beta, putative IL-18 surface loops are identified and used as a starting point for design, including a loop region 1 thought to be equivalent with the Boraschi loop of IL-1beta. Only loop region 1 complementary peptides are found to be promising leads as mini-receptor inhibitors of IL-18 but these are prevented from being properly successful owing to solubility problems. The application of "M-I pair mutagenesis" and inclusion of a C-terminal arginine residue are then sufficient to solve this problem and convert one lead peptide into a functional complementary peptide mini-receptor inhibitor of IL-18. This suggests that the biophysical and biological properties of complementary peptides can be improved in a rational and logical manner where appropriate, further strengthening the potential importance of complementary peptides as inhibitors of protein-protein interactions, even when X-ray crystal structural information is not readily available

Engineered Tumor-Targeted T Cells Mediate Enhanced Anti-Tumor Efficacy Both Directly and through Activation of the Endogenous Immune System.

Chimeric antigen receptor (CAR) T cell therapy has proven clinically beneficial against B cell acute lymphoblastic leukemia and non-Hodgkin's lymphoma. However, suboptimal clinical outcomes have been associated with decreased expansion and persistence of adoptively transferred CAR T cells, antigen-negative relapses, and impairment by an immunosuppressive tumor microenvironment. Improvements in CAR T cell design are required to enhance clinical efficacy, as well as broaden the applicability of this technology. Here, we demonstrate that interleukin-18 (IL-18)-secreting CAR T cells exhibit enhanced in vivo expansion and persistence and significantly increase long-term survival in syngeneic mouse models of both hematological and solid malignancies. In addition, we demonstrate that IL-18-secreting CAR T cells are capable of modulating the tumor microenvironment, as well as enhancing an effective endogenous anti-tumor immune response. IL-18-secreting CAR T cells represent a promising strategy to enhance the clinical outcomes of adoptive T cell therapy

Interleukin-18

Interleukin-18 (IL-18), a recently described member of the IL-1 cytokine superfamily, is now recognized as an important regulator of innate and acquired immune responses. IL-18 is expressed at sites of chronic inflammation, in autoimmune diseases, in a variety of cancers, and in the context of numerous infectious diseases. This short review will describe the basic biology of IL-18 and thereafter address its potential effector and regulatory role in several human disease states including autoimmunity and infection. IL-18, previously known as interferon-gamma (IFN-gamma)-inducing factor, was identified as an endotoxin-induced serum factor that stimulated IFN-gamma production by murine splenocytes [<sup>1</sup> ]. IL-18 was cloned from a murine liver cell cDNA library generated from animals primed with heat-killed Propionibacterium acnes and subsequently challenged with lipopolysaccharide [<sup>2</sup> ]. Nucleotide sequencing of murine IL-18 predicted a precursor polypeptide of 192 amino acids lacking a conventional signal peptide and a mature protein of 157 amino acids. Subsequent cloning of human IL-18 cDNA revealed 65% homology with murine IL-18 [<sup>3</sup>] and showed that both contain an unusual leader sequence consisting of 35 amino acids at their N terminus

Molecular mechanisms of IL-18BP regulation in DLD-1 cells: pivotal direct action of the STAT1/GAS axis on the promoter level

Interleukin (IL)-18, formerly known as interferon (IFN)-γ-inducing factor, is a crucial mediator of host defence and inflammation. Control of IL-18 bioactivity by its endogenous antagonist IL-18 binding protein (IL-18BP) is a major objective of immunoregulation. IL-18BP is strongly up-regulated by IFN-γ, thereby establishing a negative feedback mechanism detectable in cell culture and in vivo. Here we sought to investigate in D.L. Dexter (DLD) colon carcinoma cells molecular mechanisms of IL-18BP induction under the influence of IFN-γ. Mutational analysis revealed that a proximal γ-activated sequence (GAS) at the IL-18BP promoter is of pivotal importance for expression by IFN-γ-activated cells. Use of siRNA underscored the essential role of the signal transducer and activator of transcription (STAT)-1 in this process. Indeed, electrophoretic mobility shift assay and chromatin immunoprecipitation analysis proved STAT1 binding to this particular GAS site. Maximal expression of IL-18BP was dependent on de novo protein synthesis but unaffected by silencing of interferon regulatory factor-1. Altogether, data presented herein indicate that direct action of STAT1 on the IL-18BP promoter at the proximal GAS element is key to IL-18BP expression by IFN-γ-stimulated DLD-1 colon carcinoma cells

The proinflammatory cytokine interleukin 18 regulates feeding by acting on the bed nucleus of the stria terminalis

The proinflammatory cytokine IL-18 has central anorexigenic effects and was proposed to contribute to loss of appetite observed during sickness. Here we tested in the mouse the hypothesis that IL-18 can decrease food intake by acting on neurons of the bed nucleus of the stria terminalis (BST), a component of extended amygdala recently shown to influence feeding via its projections to the lateral hypothalamus (LH). We found that both subunits of the heterodimeric IL-18 receptor are highly expressed in the BST and that local injection of recombinant IL-18 (50 ng/ml) significantly reduced c-fos activation and food intake for at least 6 h. Electrophysiological experiments performed in BST brain slices demonstrated that IL-18 strongly reduces the excitatory input on BST neurons through a presynaptic mechanism. The effects of IL-18 are cell-specific and were observed in Type III but not in Type I/II neurons. Interestingly, IL-18-sensitve Type III neurons were recorded in the juxtacapsular BST, a region that contains BST-LH projecting neurons. Reducing the excitatory input on Type III GABAergic neurons, IL-18 can increase the firing of glutamatergic LH neurons through a disinhibitory mechanism. Imbalance between excitatory and inhibitory activity in the LH can induce changes in food intake. Effects of IL-18 were mediated by the IL-18R because they were absent in neurons from animals null for IL-18R\u3b1 (Il18ra-/-), which lack functional IL-18 receptors. In conclusion, our data show that IL-18 may inhibit feeding by inhibiting the activity of BST Type III GABAergic neurons