Interleukin-18 levels in the hippocampus and behavior of adult rat offspring exposed to prenatal restraint stress during early and late pregnancy

Exposure to maternal stress during prenatal life is associated with an increased risk of neuropsychiatric disorders, such as depression and anxiety, in offspring. It has also been increasingly observed that prenatal stress alters the phenotype of offspring via immunological mechanisms and that immunological dysfunction, such as elevated interleukin-18 levels, has been reported in cultures of microglia. Prenatal restraint stress (PRS) in rats permits direct experimental investigation of the link between prenatal stress and adverse outcomes. However, the majority of studies have focused on the consequences of PRS delivered in the second half of pregnancy, while the effects of early prenatal stress have rarely been examined. Therefore, pregnant rats were subjected to PRS during early/middle and late gestation (days 8-14 and 15-21, respectively). PRS comprised restraint in a round plastic transparent cylinder under bright light (6500 lx) three times per day for 45 minutes. Differences in interleukin-18 expression in the hippocampus and in behavior were compared between offspring rats and control rats on postnatal day 75. We found that adult male offspring exposed to PRS during their late prenatal periods had higher levels of anxiety-related behavior and depression than control rats, and both male and female offspring exhibited higher levels of depression-related behavior, impaired recognition memory and diminished exploration of novel objects. Moreover, an elevated level of interleukin-18 was observed in the dorsal and ventral hippocampus of male and female early- and late-PRS offspring rats. The results indicate that PRS can cause anxiety and depression-related behaviors in adult offspring and affect the expression of interleukin-18 in the hippocampus. Thus, behavior and the molecular biology of the brain are affected by the timing of PRS exposure and the sex of the offspring. All experiments were approved by the Animal Experimentation Ethics Committee at Kunming Medical University, China (approval No. KMMU2019074) in January 2019.

Evaluation of the mechanism of cordyceps polysaccharide action on rat acute liver failure

INTRODUCTION

This study aimed to investigate the mechanism of action of cordyceps polysaccharide on rat acute liver failure (ALF).

MATERIAL AND METHODS

Sixty rats were randomly divided into five groups: a normal group, a model group without cordyceps polysaccharide and groups with cordyceps polysaccharide in three different doses (5, 10 and 20 mg/ml). Serum alanine aminotransferase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and total bilirubin (TBIL) contents were measured for assessing liver function. Hematoxylin and eosin (HE) staining was used for observing liver pathology. Apoptosis was detected through the method of terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL) staining. Protein expression levels of caspase-1, interleukin-18 (IL-18), IL-10, vascular endothelial growth factor (VEGF), and stromal cell-derived factor-1α (SDF-1α) in liver tissue were detected by Western blot. Proliferating cell nuclear antigen (PCNA) and signal regulatory protein-α1 (SIRPα1) contents were measured by PCR.

RESULTS

The rat ALF model was established with D-galactosamine induced by lipopolysaccharide (LPS). After modelling, tissue HE staining showed typical manifestation of acute liver injury that emerged in the rat ALF model. The liver failure group showed higher levels of serum ALT and AST, as well as hepatocyte apoptosis, than the groups treated with cordyceps polysaccharide. Cordyceps polysaccharide can effectively suppress the protein expression of caspase-1, IL-18, and IL-10, while simultaneously increasing the protein expression of VEGF and SDF-1α, as well as the mRNA expression of PCNA and SIRPα1.

CONCLUSIONS

Cordyceps polysaccharide can alleviate the immune response and inflammatory injury in ALF by regulating the balance of pro-inflammatory and anti-inflammatory factors and reducing the apoptosis.

Analysis of genes linked to depressive-like behaviors in interleukin-18-deficient mice: Gene expression profiles in the brain

Interleukin (IL)-18 is an interferon γ-inducing inflammatory cytokine associated with function of the immune system and other physiological functions. IL-18-deficient (Il18 ^-/-) mice exhibit obesity, dyslipidemia, non-alcoholic steatohepatitis and depressive-like behavioral changes. Therefore, IL-18 has a number of important roles associated with immunity, energy homeostasis and psychiatric conditions. In the present study, gene expression in the brains of Il18 ^-/- mice was analyzed to identify genes associated with the depressive-like behaviors and other impairments displayed by Il18 ^-/- mice. Using whole genome microarray analysis, gene expression patterns in the brains of Il18 ^+/+ and Il18 ^-/- mice at 6 and 12 weeks of age were examined and compared. Subsequently, genes were categorized using Ingenuity^® Pathway Analysis (IPA). At 12 weeks of age, 2,805 genes were identified using microarray analysis. Genes related to 'Major depression' and 'Depressive disorders' were identified by IPA core analysis, and 13 genes associated with depression were isolated. Among these genes, fibroblast growth factor receptor 1 (Fgfr1); protein tyrosine phosphatase, non-receptor type 1 (Ptpn1); and urocortin 3 (Ucn3) were classed as depression-inducing and the other genes were considered depression-suppressing genes. Subsequently, the interactions between the microarray results at 6 weeks of age and the above three depression-inducing genes were analyzed to search for effector genes of depression at 12 weeks of age. This analysis identified cyclin D1 (Ccnd1) and NADPH oxidase 4 (Nox4). The microarray analysis results were correlated with the results of reverse transcription-quantitative PCR (RT-qPCR). Overall, the results suggest that Fgfr1, Ptpn1 and Ucn3 may be involved in depression-like changes and Ccnd1 and Nox4 regulate these three genes in IL-18-deficient mice.

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 CART cells represent a promising strategy to enhance the clinical outcomes of adoptive T cell therapy.

Endothelial Cell-Derived Interleukin-18 Released During Ischemia Reperfusion Injury Selectively Expands T Peripheral Helper Cells to Promote Alloantibody Production

BACKGROUND

Ischemia reperfusion injury (IRI) predisposes to the formation of donor-specific antibodies, a factor contributing to chronic rejection and late allograft loss.

METHODS

We describe a mechanism underlying the correlative association between IRI and donor-specific antibodies by using humanized models and patient specimens.

RESULTS

IRI induces immunoglobulin M-dependent complement activation on endothelial cells that assembles an NLRP3 (NOD-like receptor pyrin domain-containing protein 3) inflammasome via a Rab5-ZFYVE21-NIK axis and upregulates ICOS-L (inducible costimulator ligand) and PD-L2 (programmed death ligand 2). Endothelial cell-derived interleukin-18 (IL-18) selectively expands a T-cell population (CD4+CD45RO+PD-1^hiICOS+CCR2+CXCR5-) displaying features of recently described T peripheral helper cells. This population highly expressed IL-18R1 and promoted donor-specific antibodies in response to IL-18 in vivo. In patients with delayed graft function, a clinical manifestation of IRI, these cells were Ki-67+IL-18R1+ and could be expanded ex vivo in response to IL-18.

CONCLUSIONS

IRI promotes elaboration of IL-18 from endothelial cells to selectively expand alloreactive IL-18R1+ T peripheral helper cells in allograft tissues to promote donor-specific antibody formation.

A Batf3/Nlrp3/IL-18 Axis Promotes Natural Killer Cell IL-10 Production during Listeria monocytogenes Infection

The bacterial pathogen Listeria monocytogenes (Lm) capitalizes on natural killer (NK) cell production of regulatory interleukin (IL)-10 to establish severe systemic infections. Here, we identify regulators of this IL-10 secretion. We show that IL-18 signals to NK cells license their ability to produce IL-10. IL-18 acts independent of IL-12 and STAT4, which co-stimulate IFNγ secretion. Dendritic cell (DC) expression of Nlrp3 is required for IL-18 release in response to the Lm p60 virulence protein. Therefore, mice lacking Nlrp3, Il18, or Il18R fail to accumulate serum IL-10 and are highly resistant to systemic Lm infection. We further show that cells expressing or dependent on Batf3 are required for IL-18-inducing IL-10 production observed in infected mice. These findings explain how Il18 and Batf3 promote susceptibility to bacterial infection and demonstrate the ability of Lm to exploit NLRP3 for the promotion of regulatory NK cell activity.

Activation of Human NK Cells by Bordetella pertussis Requires Inflammasome Activation in Macrophages

Pertussis is a highly contagious respiratory infection caused by the bacterium Bordetella pertussis. Humans are the only known natural reservoir of B. pertussis. In mice, macrophages and NK cells have a key role in confining B. pertussis to the respiratory tract. However, the mechanisms underlying this process, particularly during human infections, remain unclear. Here we characterized the activation of human macrophages and NK cells in response to B. pertussis and unraveled the role of inflammasomes in this process. NLRP3 inflammasome activation by B. pertussis in human macrophage-like THP-1 cells and primary monocyte-derived macrophages (mo-MΦ) was shown by the visualization of ASC-speck formation, pyroptosis, and the secretion of caspase-mediated IL-1β and IL-18. In contrast to macrophages, stimulation of human CD56⁺CD3⁻ NK cells by B. pertussis alone did not result in activation of these cells. However, co-culture of B. pertussis-stimulated mo-MΦ and autologous NK cells resulted in high amounts of IFNγ secretion and an increased frequency of IL-2Rα⁺ and HLA-DR⁺ NK cells, indicating NK cell activation. This activation was significantly reduced upon inhibition of inflammasome activity or blocking of IL-18 in the mo-MΦ/NK cell co-culture. Furthermore, we observed increased secretion of proinflammatory cytokines in the B. pertussis-stimulated mo-MΦ/NK co-culture compared to the mo-MΦ single culture. Our results demonstrate that B. pertussis induces inflammasome activation in human macrophages and that the IL-18 produced by these cells is required for the activation of human NK cells, which in turn enhances the pro-inflammatory response to this pathogen. Our data provides a better understanding of the underlying mechanisms involved in the induction of innate immune responses against B. pertussis. These findings contribute to the knowledge required for the development of improved intervention strategies to control this highly contagious disease.

Mycophenolic acid enhanced lipopolysaccharide-induced interleukin-18 release in THP-1 cells via activation of the NLRP3 inflammasome

Background: Interleukin (IL)-18 is a pro-inflammatory cytokine that has important functions in host defense. The maturation and secretion of IL-18 has been shown to be regulated by the NOD-like receptor (NLR) family pyrin domain-containing 3 (NLRP3) inflammasome. Mycophenolic acid (MPA), the active metabolite of mycophenolate mofetil (MMF), in association with lipopolysaccharide (LPS), is able to promote the secretion of IL-18, but the mechanism remains unknown. This study aims to explore the mechanism by which MPA synergizes with LPS to induced IL-18 release. Methods: THP-1 cells were stimulated with LPS and MPA and treated with or without the inhibitors of caspase-1, Ac-YVAD-cmk or KCl; IL-18 in the supernatants was measured by ELISA. The intracellular protein levels of NF-κB p-p65, pro-IL-18, NLRP3, and cleaved caspase-1(p20) were measured by Western blot. Results: We found that MPA alone failed to induce IL-18, whereas MPA enhanced LPS-mediated IL-18 release. MPA did not affect the intracellular protein levels of NF-κB p-p65 or pro-IL-18 but activated the NLRP3 inflammasome. Ac-YVAD-cmk or increasing extracellular K⁺ blocked the activation of caspase-1 and attenuated the release of IL-18. Conclusions: Taken together, MPA synergized with LPS to induce the release of IL-18 via activating the NLRP3 inflammasome and increasing the degradation of pro-IL-18, rather than by enhancing the production of pro-IL-18.

The SPRINT trial suggests that markers of tubule cell function in the urine associate with risk of subsequent acute kidney injury while injury markers elevate after the injury

Urine markers can quantify tubular function including reabsorption (α-1 microglobulin [α1m]) and β-2-microglobulin [β2m]) and protein synthesis (uromodulin). Individuals with tubular dysfunction may be less able to compensate to insults than those without, despite similar estimated glomerular filtration rate (eGFR) and albuminuria. Among Systolic Blood Pressure Intervention Trial (SPRINT) participants with an eGFR under 60 ml/min/1.73m2, we measured urine markers of tubular function and injury (neutrophil gelatinase-associated lipocalin [NGAL], kidney injury molecule-1 [KIM-1], interleukin-18 [IL-18], monocyte chemoattractant protein-1, and chitinase-3-like protein [YKL-40]) at baseline. Cox models evaluated associations with subsequent acute kidney injury (AKI) risk, adjusting for clinical risk factors, baseline eGFR and albuminuria, and the tubular function and injury markers. In a random subset, we remeasured biomarkers after four years, and compared changes in biomarkers in those with and without intervening AKI. Among 2351 participants, 184 experienced AKI during 3.8 years mean follow-up. Lower uromodulin (hazard ratio per two-fold higher (0.68, 95% confidence interval [0.56, 0.83]) and higher α1m (1.20; [1.01, 1.44]) were associated with subsequent AKI, independent of eGFR and albuminuria. None of the five injury markers were associated with eventual AKI. In the random subset of 947 patients with repeated measurements, the 59 patients with intervening AKI versus without had longitudinal increases in urine NGAL, IL-19, and YKL-40 and only 1 marker of tubule function (α1m). Thus, joint evaluation of tubule function and injury provided novel insights to factors predisposing to AKI, and responses to kidney injury.

Dual roles of IL-18 in colitis through regulation of the function and quantity of goblet cells

The main aim of the present study was to investigate the dual roles and mechanism of interleukin (IL)‑18 in dextran sulfate sodium (DSS)‑induced colitis. Firstly, meta‑analysis was used to explore whether the levels of IL‑18 were different in patients with colon cancer or inflammatory bowel disease. The results demonstrated that IL‑18 (rs187238, ‑137G/C) increased the incidence rate of colon cancer in patients, while IL‑18 (rs187238, ‑137G/C) decreased the incidence rate of ulcerative colitis or Crohn's disease in patients. Therefore, IL‑18 (rs187238, ‑137G/C) may have a dual function in colitis. Next, the functional role of IL‑18 in colitis was further investigated, by use of a DSS‑induced colitis mouse model. Pre‑treatment of the mice with IL‑18 increased body weight, augmented colon length, reduced inflammatory infiltration, promoted mucin (Muc)‑2 expression, increased the function and quantity of goblet cells and increased the mRNA levels of resistin‑like molecule (RELM) β and trefoil factor family (TFF) 3 in mice with DSS‑induced colitis, through the IL‑22/STAT3 pathway. By contrast, treatment with IL‑18 at later stages of the disease reduced body weight, decreased colon length, enhanced inflammatory infiltration and reduced Muc‑2 expression, decreased the function and quantity of goblet cells and inhibited the mRNA levels of RELMβ and TFF3 in mice with DSS‑induced colitis. In conclusion, IL‑18 served a dual function in colitis by regulating the function of goblet cells. The anti‑inflammatory effects of IL‑18 were observed in the early stage of colitis‑induced inflammation, while the pro‑inflammatory effects were observed in the later stages of the disease.

The cleavage of gasdermin D by caspase-11 promotes tubular epithelial cell pyroptosis and urinary IL-18 excretion in acute kidney injury

Inflammation and tubular cell death are the hallmarks of acute kidney injury. However, the precise mechanism underlying these effects has not been fully elucidated. Here we tested whether caspase-11, an inflammatory member of the caspase family, was increased in cisplatin or ischemia-reperfusion-induced acute kidney injury. Caspase-11 knockout mice after cisplatin treatment exhibited attenuated deterioration of renal functional, reduced tubular damage, reduced macrophage and neutrophil infiltration, and decreased urinary IL-18 excretion. Mechanistically, the upregulation of caspase-11 by either cisplatin or ischemia-reperfusion cleaved gasdermin D (GSDMD) into GSDMD-N, which translocated onto the plasma membrane, thus triggering cell pyroptosis and facilitated IL-18 release in primary cultured renal tubular cells. These results were further confirmed in GSDMD knockout mice that cisplatin-induced renal morphological and functional deterioration as well as urinary IL-18 excretion were alleviated. Furthermore, deficiency of GSDMD significantly suppressed cisplatin-induced IL-18 release but not the transcription and maturation level of IL-18 in tubular cells. Thus, our study indicates that caspase-11/GSDMD dependent tubule cell pyroptosis plays a significant role in initiating tubular cell damage, urinary IL-18 excretion and renal functional deterioration in acute kidney injury.

Hepatitis B core antigen can regulate NLRP3 inflammasome pathway in HepG2 cells

Hepatitis B virus (HBV) has four open reading frames (ORFs) of which ORF C is consists of the pre Core and Core genes encodes the Hepatitis B core antigen (HBcAg) and Hepatitis B e antigen (HBeAg). Studies have shown that HBeAg significantly inhibits the NLRP3 inflammasome activation and interleukin-1β (IL-1β) production. However, the role of HBcAg and ORF C proteins (in this paper, ORF C proteins = HBcAg + HBeAg) were remain unclear. Our study aims to assess whether HBcAg and ORF C proteins can affect the NLRP3 inflammasome pathway. Vectors expressing ORF C proteins and HBcAg were designed and transfected into HepG2 cells. And then, cells were stimulated with lipopolysaccharide (LPS). Activation of the NLRP3 inflammasome and the levels of IL-1β and IL-18 were evaluated by Western blot analysis, quantitative reverse-transcription polymerase chain reaction, enzyme-linked immunosorbent assay, and immunofluorescence. The expression of NLRP3 and IL-1β peaked when HepG2 cells were stimulated with 1000 ng/mL LPS for 18 to 24 hours. HBcAg, but not ORF C proteins, promoted LPS-induced NLRP3 inflammasome activation and IL-1β production. These findings provide a novel mechanism on how the HBV causes liver inflammation and may provide insights into the search for new therapeutic strategies.

Predictive value of IL-18 and IL-10 in the prognosis of patients with colorectal cancer

Predictive value of serum interleukin 10 (IL-10) and interleukin 18 (IL-18) expression in patients with colorectal cancer (CRC) was investigated. This study retrospectively analyzed the medical records of 146 patients with CRC admitted to the Binzhou Medical University Hospital as the study group, and collected the physical examination data of 82 volunteers as the control group. The expression levels of IL-10 and IL-18 in the serum were measured by enzyme-linked immunosorbent assay (ELISA). A 60-month follow-up on patients in the study group was performed to make records of their prognosis. The expressions of IL-10 and IL-18 were statistically different in patients with different Dukes stages, tumor sizes, histological grades, and different situations of distant metastasis of cancer cells (P<0.05); with a gradual downward trend following the operation. The expression levels of serum IL-10 and IL-18 in the study group 7 days after the operation were lower than the levels before the operation (P<0.05), and the expression levels of IL-10 and IL-18 of patients in the study group on the day of discharge were lower than the expression levels 7 days after the operation (P<0.05). The expressions of IL-10 and IL-18 of patients with reoccurred CRC after the operation were significantly higher than that of patients without recurrence of CRC in the study group (P<0.05). Thus, IL-10 and IL-18 are highly expressed in the serum of CRC patients, which makes IL-10 and IL-18 useful to serve as indicators to determine the prognosis of CRC patients. The lower the expression levels of IL-10 and IL-18, the lower the cancer recurrence rate, the better the prognosis and the longer the survival time.

Serum interleukin-18: A novel prognostic indicator for acute respiratory distress syndrome

The aim of this study is to determine the biological function of serum interleukin-18 (IL-18) on prognosis in acute respiratory distress syndrome (ARDS).From October 2016 to September 2017, 150 patients with ARDS in the ICU were enrolled according to the Berlin 2012 definition. The enzyme-linked immunosorbent assay (ELISA) was used to detect the expression level of IL-18 in serum isolated from the patients. Patients were divided into survival group (82 cases) and non-survival group (68 cases) and followed up for at least 2 months. The serum IL-18 expression level on the prognosis was calculated by receiver operating characteristic curve (ROC).The expression level of serum IL-18 was significantly higher in the non-survival group than that in the survival group (P < .05). Based on the ROC curve, the sensitivity and specificity of IL-18 as a predictor of prognosis at a cutoff of 509.5 pg/mL were 88% and 82%, respectively, and the area under the curve (RUC) was 0.84 (P < .05).The expression level of serum IL-18 could be used to evaluate the possible outcomes of patients with ARDS.

Association between interleukin-18 variants and prostate cancer in Slovak population

Interleukin-18 (IL-18), pro-inflammatory cytokine, plays important role in antitumor immunity. Polymorphisms in the IL-18 gene may lead to its altered production/activity and such modulate susceptibility to prostate cancer. The aim of this study was to evaluate the relationship between the -607 and +105 polymorphisms in the IL-18 gene and the risk of prostate cancer development and progression in Slovak population. The study was performed using 425 patients with prostate cancer, 270 patients with benign prostatic hyperplasia (BHP) and 263 healthy male controls. The statistically significant association of the -607 AC genotype (OR = 2.24; p < 0.001), CC genotype (OR = 1.86; p = 0.006), as well as C allele (OR = 1.27; p = 0.033) with the higher risk of prostate cancer development was observed. No association of the IL-18 -607 polymorphism and BHP was detected. The subset analysis revealed the significant association of the -607 AC genotype (OR = 2.01; p = 0.008) with development of higher-grade carcinomas (Gleason score ≥7) and the strong association of the -607 AC genotype (OR = 3.11; p < 0.001), CC genotype (OR = 2.96; p < 0.001) as well as C allele (OR = 1.51; p = 0.003) with the higher risk of prostate cancer development in the group of patients with PSA < 10 ng/ml. The -607 AC genotype was also connected with significantly higher IL-18 plasma concentrations. No association between the IL-18 +105 polymorphism and prostate cancer was observed. The analysis of the distribution of the -607 and +105 haplotypes showed significant association of the - 607 C/ + 105 A and - 607 C/ + 105 C haplotypes with the risk of prostate cancer. This study found that the IL-18 -607 promoter polymorphism could contribute to prostate cancer development in Slovak population. Its presence was also associated with development of higher-grade carcinomas and therefore may influences the prognosis and aggressiveness of the disease.

Interleukin-18-deficient mice develop hippocampal abnormalities related to possible depressive-like behaviors

Interleukin-18 (IL-18) is an inflammatory cytokine linked to major depressive disorder (MDD). MDD is closely related to metabolic disorders, such as diabetes mellitus (DM) and obesity. Moreover, DM is associated with cognitive impairment and promotes apoptosis of hippocampal cells by activating pro-apoptotic and inhibiting anti-apoptotic factors. IL-18-deficient (Il18^-/-) mice are obese and have DM. Therefore, we hypothesized a close relationship between IL-18 and death of hippocampal cells, affecting neurogenesis related to behavioral changes such as MDD. Il18^-/- male mice were generated on the C57Bl/6 background and Il18^+/+ mice were used as controls. Behavioral, histopathological, and molecular responses, as well as responses to intracerebral recombinant IL-18 administration, were examined. Compared with Il18^+/+ mice, Il18^-/- mice had impaired learning and memory and exhibited lower motivation. In the Il18^-/- mice, degenerated mitochondria were detected in synaptic terminals in the molecular layer, the polymorphic layer, and in mossy fibers in the dentate gyrus, suggesting mitochondrial abnormalities. Because of the degeneration of mitochondria in the dentate gyrus, in which pro-apoptotic molecules were upregulated and anti-apoptotic factors were decreased, apoptosis inducers were not cleaved, indicating inhibition of apoptosis. In addition, neurogenesis in the dentate gyrus and the maturity of neuronal cells were decreased in the Il18^-/- mice, while intracerebral administration of recombinant IL-18 promoted significant recovery of neurogenesis. Our findings suggested that IL-18 was indispensable for mitochondrial homeostasis, sustaining clearance of degenerative neural cells, and supporting neurogenesis, normal neuronal maturation and hippocampal function.

Acute rheumatic fever associated with tenosynovitis and a unique cytokine profile

Acute rheumatic fever (ARF), caused by group A β-hemolytic streptococcus infection, is characterized by inflammation affecting several organs. There are few reports on magnetic resonance imaging (MRI) findings in patients with ARF. An 8-year-old Japanese boy presented with a prolonged fever of unknown cause and swelling of his right hand. MRI of his hand revealed tenosynovitis. Migratory arthritis and erythema marginatum appeared following the hand swelling. We diagnosed him as having ARF based on the clinical course and serological testing for group A β-hemolytic streptococcus. His serum interleukin-18 levels were lower than those typically seen in cases of systemic juvenile idiopathic arthritis (sJIA). After treatment with naproxen, his symptoms improved immediately. In conclusion, MRI findings of tenosynovitis may be useful for the diagnosis of not only sJIA but also ARF in patients presenting with a fever of unknown origin. Subsequently, the diagnosis of ARF can be confirmed with specific serological tests. Serum interleukin-18 levels may be helpful in the differential diagnosis of ARF and sJIA. Although ARF is rare in developed countries, including Japan, early diagnosis and appropriate treatment are important to prevent rheumatic heart disease.

IL-18 polymorphisms and tuberculosis susceptibility: a meta-analysis

Objective

To investigate the association between IL-18 polymorphisms and Tuberculosis(TB).

Materials and methods

We searched PubMed and Embase databases, and conducted a meta-analysis using 4 models. Data were extracted from the studies by two independent reviewers. Statistical analysis was performed using STATA 12.0 software.

Results

Five qualified studies with a total of 1293 TB patients and 1724 controls were included. There was no significant association between the IL-18 -607C>A polymorphism and TB risk in the total population(AA vs CC: OR=1.27,95% CI=0.82–1.96;-CA vs CC:OR=1.06,95% CI=0.89–1.26; Dominant model: OR =1.09, 95% CI =0.83–1.43; Recessive model:OR=1.23, 95% CI=0.92–1.65). For IL-18 -137G>C polymorphism, lack of an association was also found(GG vs CC: OR=1.42,95% CI=0.78–2.58;GC vs CC:OR=1.16,95% CI=0.62–2.16; Dominant model: OR =1.34,95% CI=0.74–2.43;Recessive model:OR=0.96,95%-CI=0.26–3.56).

Conclusion

The present meta-analysis found no evidence for IL-18 -607C>A and -137G>C polymorphisms as risk factors for TB. Further large-scale and well-designed articles are still needed to validate this result.

Elevated Serum Markers of Acute Kidney Injury in Patients With Obstructive Sleep Apnea

STUDY OBJECTIVES

Previous research revealed a positive correlation between endothelial cell injury (indicated by albuminuria) and obstructive sleep apnea (OSA). However, little else has been revealed about acute kidney injury (AKI) in patients with OSA.

METHODS

This prospective study recruited consecutive patients undergoing overnight polysomnography for evaluation of sleep apnea. Patients in whom any major disease or recent infection had been previously diagnosed were excluded. Ultimately, data from 75 patients with apnea-hypopnea indices of 5 or more were analyzed. Baseline values for the urinary albumin-creatinine ratio (UACR), serum levels for three markers of AKI (cystatin C, neutrophil gelatinase-associated lipocalin [NGAL], interleukin-18 [IL-18]), and polysomnography data were recorded and analyzed. Patients then were followed for 6 months of continuous positive airway pressure (CPAP) treatment.

RESULTS

At baseline, UACRs were greater in patients with more severe OSA (P = .005, r = .329). All three serum markers of AKI (cystatin C, NGAL, and IL-18) studied were positively correlated with OSA severity, and two (cystatin C and IL-18) were positively correlated with the frequency of oxygen desaturation during sleep. However, none of the AKI markers had positive correlations with UACR. After 6 months of CPAP treatment, UACR and IL-18 were decreased significantly in patients with good adherence.

CONCLUSIONS

Albuminuria and levels of three serum markers of AKI (cystatin C, NGAL, IL-18) were positively correlated with OSA severity, and good adherence with CPAP treatment decreased albuminuria and interleukin-18 levels. These results may provide additional tools for assessing early renal injury in patients with OSA.

Assessment of Interleukin-18 gene polymorphism and serum levels in oral lichen planus in an Indian population

BACKGROUND

Oral lichen planus (OLP) is a chronic, inflammatory disease with uncertain etiology. The aim of this study was to assess Interleukin-18 (IL-18) gene polymorphism and serum levels in OLP cases of Indian origin and to compare them with a control population of similar background.

METHODS

The assessment of single-nucleotide polymorphisms (SNPs) of IL-18 gene at promoter regions -137(G/C) and -607(C/A) was done in 70 OLP cases and 70 healthy controls using sequence-specific primer-polymerase chain reaction (SSP-PCR). In a subset of this cohort, comprising of 41 OLP cases and 41 controls, serum IL-18 levels were assessed using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Mean serum levels of IL-18 among OLP cases were significantly higher when compared to controls. Genotypic and allelic frequencies of IL-18 at position -137(G/C) showed that GG genotype and allele G was significantly higher in OLP cases, whereas, GC genotype and C allele was high in the control group. Polymorphism of IL-18 at position -607(C/A) showed no significant differences.

CONCLUSIONS

Gene polymorphism at -137GG genotype and allele G seems to be associated with genetic susceptibility to OLP whereas -137GC and allele C may have a protective role against its development. However, our study lacks clear statistical correlation, the differences observed could be caused by sampling problems and the results could not be fully representative of Indian patients with OLP. Further studies are warranted to explore the role of IL-18 genetic polymorphisms in OLP development.

Protein modeling, molecular network and molecular dynamics study of newly sequenced interleukin-18 (IL-18) gene in Mus musculus

Interleukin-18 (IL-18) belongs to the superfamily of IL-1 protein and exerts a pleiotropic pro-inflammatory effect on the body. Generally, this protein is significantly involved in immune defense during infection in cells, but sometimes its anomalous activities produce some inflammatory diseases like rheumatoid arthritis and Crohn's disease. In the present study, the IL-18 gene was isolated from mice and was subsequently cloned and sequenced. Further, the network analysis was carried out to explore the functional role of IL-18 protein in animals. The 3D protein structure of the IL-18 protein was generated and docked with appropriate 3-([3-cholamidopropyl]dimethylammonio)-1-propanesulfonate (CPS) ligand. Later the complex structure of the protein was subjected to molecular dynamics simulation (MDS) for 50 ns to determine the effect of ligand on protein. The network analysis explored the correlation of IL-18 protein with others proteins and their involvement in the different significant pathway to defend the cell from various diseases. As confirmed by MDS, the CPS:IL-18 complex was found to be highly stable. Our results further indicated that CPS ligand has the potential to act as a drug molecule, in future, for counteracting IL-18 activity. To date, no structural details were available for animal IL-18. Hence, the finding of this study will be useful in broadening the horizon towards a better understanding of the functional and structural aspects of IL-18 in animals.

Analytical Value of Cell-Free DNA Based on Alu in Psychiatric Disorders

Psychiatric disorders impose a huge burden on individuals, families, and society. The Alu repeat sequence is a member of the short interspersed nuclear element (SINE) family of mammalian genomes, however, its expression pattern and role in psychiatric disorders is unclear. The current paper aimed at determining the concentrations of Alu in patients with schizophrenia (SZ), major depressive disorder (MDD), and alcohol-induced psychotic disorder (AIPD), and to further define the role and value of Alu as a potential biomarker in psychiatric disorders. In this work, we found that the concentration of Alu was considerably incremented in patients with SZ, and a significant difference existed between patients diagnosed with SZ and MDD or AIPD. ROC analysis also indicated that Alu was effective in the complementary diagnosis of SZ, and differentially diagnosed between SZ patients and patients with MDD or AIPD. In addition, we found a positive relationship between the Alu concentrations and interleukin-1β (IL-1β) in patients with SZ, MDD, and AIPD, and between the concentrations of Alu and interleukin-18 (IL-18) in patients with SZ. Overall, the present work indicates that Alu might be an innovative biomarker for diagnosing psychiatric disorders, and provides the basis for hypotheses about the pathophysiology of psychiatric disorders.

[Expression and role of IL-18 in chronic rhinosinusitis]

Objective:To study the expression and role of interleukin-18 (IL-18) in different clinical phenotypes of chronic rhinosinusitis(CRS)and in different subtypes of CRS with nasal polyps (CRSwNP).Method:During nasal endoscopic surgery, inferior turbinates were obtained from 13 patients with nasal septum deviation (control group),uncinate processes were obtained from 10 patients with chronic rhinosinusitis without nasal polyps (CRSsNP) and nasal polyp tissues were obtained from 36 patients with CRSwNP, respectively. IL-5 expression in CRSwNP was detected by ELISA, and the expression of IL-18 mRNA and protein in different subtypes of CRS were assessed by real-time PCR, ELISA and immunohistochemistr.Result:CRSwNP was divided into 12 cases of IL-5 positive nasal polyps (IL-5+NP)group and 24 cases of IL-5 negative nasal polyps (IL-5-NP)group. The expression of IL-18 mRNA and protein in all CRSsNP,IL-5+NP and IL-5-NP groups were higher than that in control group (P<0.01 or P<0.05),but no significant difference existed between IL-5+NP and IL-5-NP (P>0.05) group. IL-18 also expresses in epithelial cells of normal nasal mucosa.Conclusion:CRSwNP can be divided into two main subtypes: IL-5+NP and IL-5-NP. The increasing expression of IL-18 in CRSsNP, IL-5+NP and IL-5-NP compared with control group indicates that IL-18 may play a key role in the pathogenesis of CRS, and IL-18 expression in nasal polyps is not affected by the type of inflammation. The possible presence of balance between IL-18 and IL-18 binding protein in normal nasal mucosa provides a new way for research and treatment of CRS.

Cross-sectional correlates of increased IL-18 but reduced fetuin-A and oxytocin with adiposity and blood indices in metabolic syndrome patients with and without prediabetes

BACKGROUND

Oxytocin (OXT), fetuin-A and interleukin-18 (IL-18) are involved in the development and progression of metabolic syndrome (MetS) and prediabetes (pre/T2DM).

AIMS PARTICIPANTS AND METHODS

This study aimed to compare and correlate the plasma levels of OXT, fetuin-A and IL-18 with clinical parameters, haematological indices and adiposity indices in Jordanian MetS subjects. In a cross-sectional study, 30 normoglycaemic lean study participants (control), 30 MetS study participants, and 29 MetS pre/T2DM study participants were recruited.

RESULTS

Median circulating levels of both OXT and fetuin-A were lower in MetS and MetS pre/T2DM versus control group. OXT (pg/ml; median interquartile range): MetS 1975.4 and MetS pre/T2DM 1403 versus control 4176.6 (p = 0.009 and p = 0.001, respectively). For fetuin-A (ng/ml), MetS (5784) and MetS pre/T2DM (2154) were lower versus control (6756.3) (p = 0.040 and p = 0.007, respectively). Neither biomarker was described as substantially different in MetS versus MetS pre/T2DM (p = 0.071 and p = 0.155, respectively). Conversely, a non-significant increase in IL-18 was observed in the MetS and MetS pre/T2DM groups compared to normoglycaemic lean controls (232 and 287.5, p > 0.05 versus 108 for both). In addition, conicity index (C-index), atherogenicity index (TG-HDL-C), waist to hip ratio, mean platelet volume (MPV; fl) and red cell distribution width (RDW-CV%) in both MetS and MetS pre/T2DM were significantly higher (p < 0.001) versus controls. However all above MetS-related indices were not ascribed any statistically marked variation in the MetS group when compared to the MetS pre/T2DM group. Both total study pool of recruits' fetuin-A (Spearman r = -2.66, p = 0.049) as well as MetS pre/T2DM group IL-18 (Spearman r = 0.380, p = 0.046) were inversely correlated with RDW-CV%. OXT in MetS inversely correlated with waist circumference/hip circumference ratio (Spearman r = -0.387, p = 0.038). No other pronounced associations between biomarkers could be detected in any study arm.

CONCLUSION

These findings substantiate the clinical relevance and significance of OXT, fetuin-A and IL-18 as surrogate screening/prognostic tools and therapeutic targets to predict/prevent metabolic dysregularities and anomalies.

Interleukin-18 and diabetic nephropathy: A review

The inflammatory response has an important role in the pathophysiology of diabetic nephropathy that is contributed to by inflammatory mediators such as interleukin-1 (IL-1), IL-6, IL-18, tumor necrosis factor-α, and macrophage chemotactic protein-1; however, the role of IL-18 seems to be more specific than other cytokines in the inflammatory process. IL-18 is expressed in renal tissue and is upregulated by several stimuli including hyperglycemia. The expression/urinary level of IL-18 is positively correlated with the progression of diabetic nephropathy and the urinary albumin excretion rate. In this review, we have focused on the molecular pathways modulating the relationship between IL-18 and diabetic nephropathy.

Anti-inflammatory Effects of Homotaurine in Patients With Amnestic Mild Cognitive Impairment

Alzheimer’s disease (AD) is a fatal dementing neurodegenerative disease, currently lacking an efficacious disease-modifying therapy. In the last years, there has been some interest in the use of homotaurine as a potential therapeutic compound for AD, but more work is still needed to prove its efficacy as disease modifier in dementia. Since inflammation is believed to play a key role in AD development, we sought to investigate here the in vivo homotaurine effect on inflammatory response in patients at the earliest stages of AD, i.e., suffering from amnestic mild cognitive impairment (aMCI). Thus, the present study aims to evaluate the effects of homotaurine supplementation on cytokine serum levels and memory performances in MCI patients. Neuropsychological, clinical and cytokine assessment was performed at baseline (T0) and after 1 year (T12) of homotaurine supplementation in 20 patients categorized as carriers (n = 9) or no carriers (n = 11) of the ε4 allele of the apolipoprotein E (APOE) gene, the strongest genetic risk factor for AD. The serum levels of the pro-inflammatory mediators Interleukin (IL) 1β, Tumor necrosis factor-alpha (TNFα), IL-6 and IL-18, contextually with the anti-inflammatory molecules IL-18 binding protein (IL-18BP) and Transforming growth factor-beta (TGFβ), were analyzed to explore significant differences in the inflammatory status between T0 and T12 in the two APOE variant carrier groups. No significant differences over time were observed in patients as for most cytokines, except for IL-18. Following homotaurine supplementation, patients carrying the APOEε4 allele showed a significant decrease in IL-18 (both in its total and IL-18BP unbound forms), in turn associated with improved short-term episodic memory performance as measured by the recency effect of the Rey 15-word list learning test immediate recall. Thus, homotaurine supplementation in individuals with aMCI may have a positive consequence on episodic memory loss due, at least in part, to homotaurine anti-inflammatory effects. This study strongly suggests that future research should focus on exploring the mechanisms by which homotaurine controls brain inflammation during AD progression.

Evaluation on the effect of hydrogen sulfide on the NLRP3 signaling pathway and its involvement in the pathogenesis of atherosclerosis

BACKGROUND

As a common disease, the incidence of atherosclerosis (AS) in the world is high. Therefore, we aimed to evaluate the involvement of hydrogen sulfide (H ₂ S)/cystathionine γ-lyase (CSE) in the pathogenesis of AS as well as their possible signaling pathways.

METHODS

Enzyme-linked immunosorbent assay, real-time polymerase chain reaction, and Western blot analysis were used to detect the effect of CSE on the expression of inflammatory cytokines, ie, H ₂ S, thioredoxin-interacting protein (TXNIP), NLRP3, apoptosis-associated speck-like protein (ASC), caspase-1, and interleukin (IL)-1β. In addition, immunohistochemistry and Western blot analysis were performed to detect the levels of TXNIP, NLRP3, ASC, caspase-1, IL-1β, and IL-18 among different groups.

RESULT

Knockdown of CSE by the transfection of CSE small interfering RNA upregulated the levels of two inflammatory cytokines, ie, IL-1β and IL-18. In addition, the downregulation of CSE promoted the expression of TXNIP, NLRP3, ASC, caspase-1, and IL-1β in THP-1 cells. Meanwhile, treating the cells with sodium hydrosulfide (NaHS) inhibited the productions of IL-1β and IL-18. Furthermore, upregulation of H ₂ S synthesis by treating the cells with NaHS also reduced the protein levels of TXNIP, NLRP3, ASC, caspase-1, and IL-1β. Finally, the protein levels of TXNIP and NLRP3 in the AS group were much higher than those in the AS + H ₂ S group, which in turn was higher than the sham group. In addition, the AS group displayed the highest protein levels of TXNIP, NLRP3, ASC, caspase-1, IL-1β, and IL-18, while the levels of these proteins in the AS + H ₂ S group were higher than those in the sham group.

CONCLUSION

In summary, the present finding suggested a possible linkage between H ₂ S metabolism and AS through the H ₂ S/CSE-TXNIP-NLRP3-IL-18/IL-1β-nitric oxide (NO) signaling pathway.

Comparison of urine neutrophil gelatinase-associated lipocalin and interleukin-18 in prediction of acute kidney injury in adults

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL) and interleukin-18 (IL-18) were considered as the most promising biomarkers in prediction of acute kidney injury (AKI), but the priority of them remains unclear.

METHODS

Databases of PubMed, Elsevier, Cochrane library, and Web of science were searched until August 23, 2017 for studies investigated the diagnostic value of urine NGAL (uNGAL) and urine IL-18 (uIL-18) for AKI in adults. Statistical analysis and investigation of heterogeneity source were using RevMan5.3, MetaDiSc1.40, and Stata14.0.

RESULTS

A total of 7 studies were included involving 2315 patients from 7 countries in this article, of whom 443 (19.1%) developed AKI. The present meta-analysis demonstrated that uNGAL was more valuable compare with uIL-18 with effect size of 1.09 (95% CI 1.03-1.15, P = .004) in specificity, but not in sensitivity with effect size of 1.12 (95% CI 0.98-1.29, P = .104). Subgroup analysis presented that research design may be a foundation affecting the diagnostic accuracy of uNGAL and uIL-18 for AKI. No substantial publication bias was found.

CONCLUSIONS

uNGAL is more specific for prediction of AKI in adults as compared with uIL-18.

Clinical effects of tanshinone IIA sodium sulfonate combined with trimetazidine and levocarnitine in the treatment of AVMC and its effects on serum TNF-α, IL-18 and IL-35

Clinical effects of tanshinone IIA sodium sulfonate combined with trimetazidine and levocarnitine in the treatment of acute viral myocarditis (AVMC) were investigated. Eighty-six patients with AVMC treated in Dongying City People's Hospital from August 2016 to July 2017 were selected and randomly divided into control group (n=43) and observation group (n=43). Patients in control group were treated with tanshinone IIA sodium sulfonate, while those in observation group were treated with trimetazidine and levocarnitine. The curative effect and improvement in clinical symptoms were compared between the two groups of patients, and enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of heart-type fatty acid-binding protein (H-FABP), creatine kinase-MB (CK-MB) and cardiac troponin I (cTnI) in patients after treatment. Besides, the changes in levels of serum tumor necrosis factor-α (TNF-α), interleukin (IL)-18 and IL-35 were detected via ELISA. The total effective rate of treatment in observation group was significantly higher than that in control group (p<0.05). The improvement in clinical symptoms in observation group was significantly superior to that in control group (p<0.05). After treatment, levels of H-FABP, CK-MB and cTnI in observation group were obviously lower than those in control group (p<0.05). At 3, 5 and 7 days after treatment, the levels of TNF-α and IL-18 in both groups of patients were decreased compared with those before treatment, but the level of IL-35 was increased compared with that before treatment, and changes in observation group were more significant than those in control group (p<0.05). Tanshinone IIA sodium sulfonate combined with trimetazidine and levocarnitine has definite curative effects in the treatment of patients with AVMC, which can alleviate myocardial injury with higher safety, and effectively mitigate the inflammatory response in patients, so it is of great clinical significance.

Inflammasome, pyroptosis, and cytokines in myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion injury induces a sterile inflammatory response, leading to further injury that contributes to the final infarct size. Locally released danger-associated molecular patterns lead to priming and triggering of the NOD-like receptor protein 3 inflammasome and amplification of the inflammatory response and cell death by activation of caspase-1. We review strategies inhibiting priming, triggering, or caspase-1 activity or blockade of the inflammasome-related cytokines interleukin-1β and interleukin-18, focusing on the beneficial effects in experimental models of acute myocardial infarction in animals and the initial results of clinical translational research trials.

Association of IL-8 gene promoter -251 A/T and IL-18 gene promoter -137 G/C polymorphisms with head and neck cancer risk: a comprehensive meta-analysis

Purpose

No consensus exists on the impact of polymorphisms in cytokines (such as interleukin IL-8 and IL-18) on cancer risk; moreover, there is very little evidence regarding head and neck cancer (HNC).

Methods

Thus, a meta-analysis including 22 studies with 4731 cases and 8736 controls was conducted to evaluate this association. The summary odds ratio (OR) and corresponding 95% confidence intervals (CIs) for C-X-C motif chemokine ligand 8 (CXCL8, which encodes IL-8) and IL-18 polymorphisms and HNC risk were estimated.

Results

The results showed a significantly increased risk of HNC susceptibility for IL18 −137 G/C in five genetic models, but, interestingly, no significant association was found for the CXCL8 −251 A/T polymorphism. When stratified by cancer type, an increased risk of nasopharyngeal cancer was found for both −137 G/C and −251A/T. When the studies were stratified by ethnicity and genotyping method, there were significant associations between Asian populations and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) studies for −137 G/C, and African populations for −251 A/T in some genetic models. A positive association was also found between the population-based groups in some models for −137 G/C; conversely, significantly decreased risk was found among the −251 A/T hospital-based group. Meta-regression was also conducted. The publication year, control source, and cancer type contributed to CXCL8 −251 A/T heterogeneity; however, no factors were found that contributed to IL-18 −137 G/C heterogeneity. Marginal significance was found in the recessive model for IL-18 −137 G/C by Egger’s test, whereas no publication bias was detected for CXCL8 −251 A/T.

Conclusions

The results indicate that the IL-18 −137 G/C polymorphism is associated with HNC risk, especially nasopharyngeal cancer, in Asian populations and, when using PCR-RFLP, CXCL8 −251 A/T polymorphisms play a complex role in HNC development.

Correlation between the expression of IL‑18 and deep venous thrombosis

The present study aimed to investigate the effect of the expression of interleukin (IL)‑18 and related markers on deep venous thrombosis (DVT) to examine their correlation. Sprague‑Dawley rats of different models were established and were randomly assigned into three groups. The expression of IL‑18, nuclear factor (NF)‑κB and von Willebrand factor (vWF) were detected in blood samples. The inferior vena cava (IVC) was ligated to establish the DVT model. Rat IL‑18 overexpression and inhibition vectors were constructed. The expression levels of IL‑18 and related markers in the venous wall were compared between the model group and the control group using reverse transcription‑quantitative polymerase chain reaction and western blot analyses. Following the culture of human umbilical vein endothelial cells (HUVECs), IL‑18 was added to the cells, following which the growth of the HUVECs, and changes in vWF and other endothelial functional markers were analyzed. The IVC model demonstrated complete thrombosis at 8 h and stable thrombosis at 24 h. At 24 h following model establishment, the expression levels of IL‑18, NF‑κB and vWF were high in the blood samples with the occurrence and development of thrombosis (P<0.05). The weight, length and weight/length ratio of thrombi in each model group showed significant differences from those in the control group (P<0.05) with the overexpression of IL‑18, and the expression levels of NF‑κB and vWF in venous tissues were altered with abnormal expression levels of IL‑18. IL‑18 damaged HUVECs and significantly increased viability in early‑stage apoptosis, promoted the upregulation of vWF and P‑selectin, and reduced tissue plasminogen activator. IL‑18 and the related markers were closely associated with the occurrence and development of DVT.

Interleukin-18: Biological properties and role in disease pathogenesis

Initially described as an interferon (IFN)γ‐inducing factor, interleukin (IL)‐18 is indeed involved in Th1 and NK cell activation, but also in Th2, IL‐17‐producing γδ T cells and macrophage activation. IL‐18, a member of the IL‐1 family, is similar to IL‐1β for being processed by caspase 1 to an 18 kDa‐biologically active mature form. IL‐18 binds to its specific receptor (IL‐18Rα, also known as IL‐1R7) forming a low affinity ligand chain. This is followed by recruitment of the IL‐18Rβ chain. IL‐18 then uses the same signaling pathway as IL‐1 to activate NF‐kB and induce inflammatory mediators such as adhesion molecules, chemokines and Fas ligand. IL‐18 also binds to the circulating high affinity IL‐18 binding protein (BP), such as only unbound free IL‐18 is active. IL‐18Rα may also bind IL‐37, another member of the IL‐1 family, but in association with the negative signaling chain termed IL‐1R8, which transduces an anti‐inflammatory signal. IL‐18BP also binds IL‐37 and this acts as a sink for the anti‐inflammatory properties of IL‐37. There is now ample evidence for a role of IL‐18 in various infectious, metabolic or inflammatory diseases such as influenza virus infection, atheroma, myocardial infarction, chronic obstructive pulmonary disease, or Crohn's disease. However, IL‐18 plays a very specific role in the pathogenesis of hemophagocytic syndromes (HS) also termed Macrophage Activation Syndrome. In children affected by NLRC4 gain‐of‐function mutations, IL‐18 circulates in the range of tens of nanograms/mL. HS is treated with the IL‐1 Receptor antagonist (anakinra) but also specifically with IL‐18BP. Systemic juvenile idiopathic arthritis or adult‐onset Still's disease are also characterized by high serum IL‐18 concentrations and are treated by IL‐18BP.

Association analysis of interleukin-18 gene promoter region polymorphisms and susceptibility to sporadic breast cancer in Chinese Han women

BACKGROUND

Interleukin-18-137G/C, -607G/T polymorphisms play multiple roles in various cancers. However, studies focused on its involvement in breast cancer remain controversial, and no study has taken the interaction between interleukin-18 (IL-18) gene polymorphism and body mass index (BMI), menopause into consideration. The study investigated the association between IL-18-137, -607 polymorphisms and risk of breast cancer and a possible interaction between the 2 single nucleotide polymorphisms (SNPs) and BMI, menopause in Chinese Han woman.

METHODS

A total of 488 participants, including 178 patients with breast cancer, 150 patients with benign breast disease and 160 healthy controls were recruited for this study. Polymerase chain reaction (PCR)-direct sequencing technology was used to identify the genotypes.

RESULTS

137 G/C genotype can decrease the risk of breast cancer (OR = 0.54, 95% CI: 0.31-0.93; P = .025). In benign group, subjects with G/C genotype of IL-18-137G/C polymorphism had a 1.89-fold increased risk of developing breast cancer (95% CI = 1.05-3.41; P = .032). Among postmenopausal subjects, people with G/T genotype of IL-18-607 polymorphism had a 7.97-fold increased risk of lymph node metastasis compared with those with T/T homozygotes (95% CI = 1.95-32.65; P = .0045). Among Overweight and obese patients with breast cancer (BMI ≥ 24), people with G/T genotype of IL-18-607 polymorphism had a 5.45-fold increased risk of lymph node metastasis compared with those with T/T homozygotes (95% CI = 1.74-17.06; P = .034).

CONCLUSIONS

IL-18-137 G/C genotype may be a protective factor for healthy group, but a risk factor for benign group. IL-18-607 G/T genotype have an interaction with menopausal and BMI. The synergetic effect can further increase the risk of lymph node metastasis for breast cancer patients.

Analysis of Serum Interleukin (IL)-1β and IL-18 in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a chronic multisystem autoimmune disease characterized by biological and clinical heterogeneity. The interleukin (IL)-1 superfamily is a group of innate cytokines that contribute to pathogenesis in many autoimmune diseases. IL-1β and IL-18 are two members that have been shown to play a role in murine lupus-like models, but their role in human SLE remains poorly understood. Here, IL-1β and IL-18 were quantified by enzyme-linked immunosorbent assay in the serum of healthy controls (HCs) and SLE patients from a prospectively followed cohort. Disease activity and organ damage were assessed using SLE disease activity index 2000 (SLEDAI-2K) and SLE damage index scores (SDI), respectively. 184 SLE patients (mean age 44.9 years, 91% female, 56% double-stranded deoxyribonucleic acid positive) were compared to 52 HC. SLE patients had median [IQR] SLEDAI-2K of 4 [2,6], and SDI of 1 [0–2]. Serum IL-18 levels were statistically significantly higher in SLE patients compared to HCs. Univariable linear regression analyses showed that patients with active renal disease or irreversible organ damage had statistically significantly elevated serum IL-18 levels. The association between serum IL-18 and active renal disease was confirmed in multivariable analysis after adjusting for ethnicity and organ damage. High baseline serum IL-18 levels were associated with organ damage at the subsequent visit. Serum IL-1β levels were not significantly elevated in SLE patients when compared to HCs and had no association with overall or organ-specific disease activity or organ damage in cross-sectional and longitudinal analyses. Our data suggest that serum IL-18 and IL-1β have different clinical implications in SLE, with IL-18 being potentially associated with active renal disease.

Gold Nanoparticle Toxicity in Mice and Rats: Species Differences

Nanotoxicity studies are greatly needed to advance nanomedical technologies into clinical practice. We assessed the toxic effects of a single intravenous exposure to commercially available gold nanoparticles (GNPs) in mice and rats. Fifteen-nm GNPs were purchased and independently characterized. Animals were exposed to either 1,000 mg GNPs/kg body weight (GNP group) or phosphate-buffered saline. Subsets of animals were euthanized and samples collected at 1, 7, 14, 21, and 28 days postexposure. Independent characterization demonstrated that the physicochemical properties of the purchased GNPs were in good agreement with the information provided by the supplier. Mice exposed to GNPs developed granulomas in the liver and transiently increased serum levels of the pro-inflammatory cytokine interleukin-18. No such alterations were found in rats. While there was no fatality in mice post-GNP exposure, a number of the rats died within hours of GNP administration. Differences in GNP biodistribution and excretion were also detected between the two species, with rats having a higher relative accumulation of GNPs in spleen and greater fecal excretion. In conclusion, GNPs have the ability to incite a robust macrophage response in mice, and there are important species-specific differences in their biodistribution, excretion, and potential for toxicity.

Leptin, hs-CRP, IL-18 and urinary protein before and after treatment of children with nephrotic syndrome

We aimed to analyze the changes in plasma leptin, serum inflammatory factors and urinary protein in children with nephrotic syndrome before and after treatment and their clinical significance. A total of 28 children treated and diagnosed with nephrotic syndrome between November 2015 and October 2016 were selected as treatment group, while 25 healthy children were selected as control group. There were no statistically significant differences in age, sex, body mass index (BMI), serum albumin and other general data between treatment group and control group (P>0.05). There was a positive correlation between serum high-sensitivity C-reactive protein (hs-CRP) level and 24 h urinary protein level in children with nephrotic syndrome before treatment (r=0.408, P=0.005). Twenty-four hours urinary protein, urea nitrogen (BUN) and serum creatinine (SCr) levels in children with nephrotic syndrome before treatment were significantly higher than those in normal children, and these indexes were significantly decreased after treatment. The levels of plasma leptin and serum inflammatory factors (hs-CRP and IL-18) in children with nephrotic syndrome before treatment were obviously higher than those in normal children, and these indexes were obviously decreased after treatment. In conclusion, the detection of changes in plasma leptin, serum inflammatory factors (hs-CRP and IL-18) and urinary protein in children with nephrotic syndrome before and after treatment has important reference value for reflecting the severity of disease and evaluating the prognosis of children with nephrotic syndrome.

Interleukin-1α Mediates Ozone-Induced Myeloid Differentiation Factor-88-Dependent Epithelial Tissue Injury and Inflammation

Air pollution associated with ozone exposure represents a major inducer of respiratory disease in man. In mice, a single ozone exposure causes lung injury with disruption of the respiratory barrier and inflammation. We investigated the role of interleukin-1 (IL-1)-associated cytokines upon a single ozone exposure (1 ppm for 1 h) using IL-1α-, IL-1β-, and IL-18-deficient mice or an anti-IL-1α neutralizing antibody underlying the rapid epithelial cell death. Here, we demonstrate the release of the alarmin IL-1α after ozone exposure and that the acute respiratory barrier injury and inflammation and airway hyperreactivity are IL-1α-dependent. IL-1α signaling via IL-1R1 depends on the adaptor protein myeloid differentiation factor-88 (MyD88). Importantly, epithelial cell signaling is critical, since deletion of MyD88 in lung type I alveolar epithelial cells reduced ozone-induced inflammation. In addition, intratracheal injection of recombinant rmIL-1α in MyD88^acid mice led to reduction of inflammation in comparison with wild type mice treated with rmIL-1α. Therefore, a major part of inflammation is mediated by IL-1α signaling in epithelial cells. In conclusion, the alarmin IL-1α released upon ozone-induced tissue damage and inflammation is mediated by MyD88 signaling in epithelial cells. Therefore, IL-1α may represent a therapeutic target to attenuate ozone-induced lung inflammation and hyperreactivity.

Mesenchymal stem cells expressing interleukin-18 inhibit breast cancer in a mouse model

Development of an improved breast cancer therapy has been an elusive goal of cancer gene therapy for a long period of time. Human mesenchymal stem cells derived from umbilical cord (hUMSCs) genetically modified with the interleukin (IL)-18 gene (hUMSCs/IL-18) were previously demonstrated to be able to suppress the proliferation, migration and invasion of breast cancer cells in vitro. In the present study, the effect of hUMSCs/IL-18 on breast cancer in a mouse model was investigated. A total of 128 mice were divided into 2 studies (the early-effect study and the late-effect study), with 4 groups in each, including the PBS-, hUMSC-, hUMSC/vector- and hUMSC/IL-18-treated groups. All treatments were injected along with 200 µl PBS. Following therapy, the tumor size, histological examination, and expression of lymphocytes, Ki-67, cluster of differentiation 31 and cytokines [interleukin (IL)-18, IL-12, interferon (IFN)-γ and TNF-α] in each group were analyzed. Proliferation of cells (assessed by measuring tumor size and Ki-67 expression) and metastasis, (by determining pulmonary and hepatic metastasis) of breast cancer cells in the hUMSC/IL-18 group were significantly decreased compared with all other groups. hUMSCs/IL-18 suppressed tumor cell proliferation by activating immunocytes and immune cytokines, decreasing the proliferation index of proliferation marker protein Ki-67 of tumor cells and inhibiting tumor angiogenesis. Furthermore, hUMSCs/IL-18 were able to induce a more marked and improved therapeutic effect in the tumor sites, particularly in early tumors. The results of the present study indicate that hUMSCs/IL-18 were able to inhibit the proliferation and metastasis of breast cancer cells in vivo, possibly leading to an approach for a novel antitumor therapy in breast cancer.

The Hunt for the Source of Primary Interleukin-4: How We Discovered That Natural Killer T Cells and Basophils Determine T Helper Type 2 Cell Differentiation In Vivo

Interleukin (IL)-4 plays a central role in determining the phenotype of naïve CD4⁺ T cells by promoting their differentiation into IL-4-producing T helper type 2 (Th2) cells, which are crucial for the induction of allergic inflammation. However, to date, the potential sources of “primary IL-4” in vivo, as distinguished from IL-4 produced by Th2 cells, remain unclear. Here, I describe the research I carried out in collaboration with Dr. William E. Paul to identify “primary IL-4”-producing cells and Th2 cell differentiation in vivo.

Unique Action of Interleukin-18 on T Cells and Other Immune Cells

Interleukin (IL)-18 was originally discovered as a factor that enhances interferon (IFN)-γ production by anti-CD3-stimulated Th1 cells, particularly in association with IL-12. IL-12 is a cytokine that induces development of Th1 cells. IL-18 cannot induce Th1 cell development, but has the capacity to activate established Th1 cells to produce IFN-γ in the presence of IL-12. Thus, IL-18 is regarded as a proinflammatory cytokine that facilitates type 1 responses. However, in the absence of IL-12 but presence of IL-2, IL-18 stimulates natural killer cells, NKT cells, and even established Th1 cells to produce IL-3, IL-9, and IL-13. Thus, IL-18 also facilitates type 2 responses. This unique function of IL-18 contributes to infection-associated allergic diseases. Together with IL-3, IL-18 stimulates mast cells and basophils to produce IL-4, IL-13, and chemical mediators such as histamine. Thus, IL-18 also induces innate-type allergic inflammation. IL-18 belongs to the IL-1 family of cytokines, which share similar molecular structures, receptors structures, and signal transduction pathways. Nevertheless, IL-18 shows a unique function by binding to a specific receptor expressed on distinct types of cells. In this review article, I will focus on the unique features of IL-18 in lymphocytes, basophils, and mast cells, particularly in comparison with IL-33.

NLRP3 Inhibitors as Potential Therapeutic Agents for Treatment of Inflammatory Bowel Disease

BACKGROUND

Inflammatory bowel disease (IBD) is a group of intestinal disorders characterised by chronic relapsing inflammation of the small intestine and colon. IBD manifests as either ulcerative colitis or Crohn's disease and increases the risk of developing colorectal cancer.

METHODS

Here, we have reviewed current treatment regimen for IBD utilising anti-inflammatory drugs, immune system suppressors and antibiotics or a combination of these. However, these therapeutics lead to a number of adverse effects, remission or significant non-responsiveness creating an urgent need to develop potent drugs with novel mechanisms of action for IBD.

RESULTS

The inflammasome is a multiprotein complex that assembles to a key innate immune system signalling platform and is involved in the pathogenesis of inflammatory and autoimmune diseases. A number of investigations show that the NLRP3 inflammasome recognizes microbial and cell stress components and serve as a platform for caspase-1 activation and pro-inflammatory cytokine IL-1β, IL18 maturation. Although the exact aetiology of IBD is unknown, uncontrolled NLRP3 Inflammasome activation has shown to play a major role in the chronic intestinal inflammation and mature IL-1β and IL18 are consistently associated with increased colitis and colitis associated colorectal cancer development.

CONCLUSION

In this review, we discuss the experimental NLRP3 inhibitors that have been investigated in IBD experimental models. The potential mechanism of action of these inhibitors such as inhibiting NF-κB activation and decreasing mitochondrial reactive oxygen species are discussed in detail. We further expand the controversial role of NLRP3 in IBD and future issues that might arise from the long term use of NLRP3 inhibitors in IBD therapy.

The relationship between IL-18 and atherosclerotic cardiovascular risk in Egyptian lean women with polycystic ovary syndrome

BACKGROUND

Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder among women of reproductive age. The evidence in support of low-grade inflammation in PCOS as an etiology is emerging. Inflammation is likely to be associated with other prominent aspects of PCOS including insulin resistance (IR) and cardiovascular disease (CVD) risk. Interleukin-18 (IL-18) is considered as a strong marker of inflammation.

OBJECTIVES

Evaluation of the relation between serum IL-18 and atherosclerotic CVD (ASCVD) risk in Egyptian lean females with PCO.

METHODS

This study included control group of healthy lean normally menstruating females, lean PCOS group (BMI < 25 kg/m²), and obese PCOS group (BMI > 25 kg/m²) presented with infertility and diagnosed according to Rotterdam criteria. Measurements of serum lipid profile, IR, and IL-18 were done.

RESULTS

Lipid accumulation product (LAP), IR and ASCVD risk were significantly higher in PCOS patients (lean and obese) compared to controls and in obese compared to lean. Serum IL-18 was significantly higher in the PCOV groups compared to the controls and correlated directly with LAP, IR and ASCVD risk.

CONCLUSION

IL-18 is elevated in PCOS patients even in lean ones and is correlated with IR and ASCVD risk.

Interleukin-18 Amplifies Macrophage Polarization and Morphological Alteration, Leading to Excessive Angiogenesis

M2 macrophage (Mφ) promotes pathologic angiogenesis through a release of pro-angiogenic mediators or the direct cell–cell interaction with endothelium in the micromilieu of several chronic inflammatory diseases, including rheumatoid arthritis and cancer, where interleukin (IL)-18 also contributes to excessive angiogenesis. However, the detailed mechanism remains unclear. The aim of this study is to investigate the mechanism by which M2 Mφs in the micromilieu containing IL-18 induce excessive angiogenesis in the in vitro experimental model using mouse Mφ-like cell line, RAW264.7 cells, and mouse endothelial cell line, b.End5 cells. We discovered that IL-18 acts synergistically with IL-10 to amplify the production of Mφ-derived mediators like osteopontin (OPN) and thrombin, yielding thrombin-cleaved form of OPN generation, which acts through integrins α4/α9, thereby augmenting M2 polarization of Mφ with characteristics of increasing surface CD163 expression in association with morphological alteration. Furthermore, the results of visualizing temporal behavior and morphological alteration of Mφs during angiogenesis demonstrated that M2-like Mφs induced excessive angiogenesis through the direct cell–cell interaction with endothelial cells, possibly mediated by CD163.

Increased Expression of Interleukin-18 mRNA is Associated with Carotid Artery Stenosis

Background:

Carotid artery stenosis is the atherosclerotic narrowing of the proximal internal carotid artery and one of the primary causes of stroke. Elevated expression of the pleiotropic proinflammatory cytokine interleukin-18 has been demonstrated in human atherosclerotic plaques.

Aims:

To investigate whether the mRNA expression levels of interleukin-18 and interleukin-18-binding protein and interleukin-18 −137 G/C (rs187238) variants are associated with carotid artery stenosis development.

Study Design:

Case-control study.

Methods:

The mRNA expression levels of interleukin-18 and interleukin-18-binding protein and interleukin-18 rs187238 variants were evaluated by quantitative real-time polymerase chain reaction and real-time polymerase chain reaction, respectively, in the peripheral blood mononuclear cells of 70 patients with carotid artery stenosis (36 symptomatic, 34 asymptomatic) and 75 healthy controls.

Results:

Interleukin-18 mRNA expression was significantly increased in carotid artery stenosis patients compared to that in healthy controls (p=0.01). However, no significant difference was observed between interleukin-18-binding protein mRNA expression levels in patients with carotid artery stenosis and those in controls (p=0.101). Internal carotid artery stenosis severity was significantly higher in symptomatic patients than that in asymptomatic patients (p<0.001). A significant relationship was identified between interleukin-18 expression and internal carotid artery stenosis severity in patients with carotid artery stenosis (p=0.051). Interleukin-18 rs187238 polymorphism genotype frequencies did not significantly differ between patients with carotid artery stenosis and controls (p=0.246). A significant difference was identified between interleukin-18-binding protein gene expression and symptomatic and asymptomatic patients (p=0.026), but there was no difference in interleukin-18 expression between the symptomatic and asymptomatic subgroups (p=0.397).

Conclusion:

Interleukin-18 mRNA expression may affect carotid artery stenosis etiopathogenesis and internal carotid artery stenosis severity and also may play a mechanistic role in the pathogenesis of carotid artery stenosis, influencing the appearance of symptoms.

A Prominent Role of Interleukin-18 in Acetaminophen-Induced Liver Injury Advocates Its Blockage for Therapy of Hepatic Necroinflammation

Acetaminophen [paracetamol, N-acetyl-p-aminophenol (APAP)]-induced acute liver injury (ALI) not only remains a persistent clinical challenge but likewise stands out as well-characterized paradigmatic model of drug-induced liver damage. APAP intoxication associates with robust hepatic necroinflammation the role of which remains elusive with pathogenic but also pro-regenerative/-resolving functions being ascribed to leukocyte activation. Here, we shine a light on and put forward a unique role of the interleukin (IL)-1 family member IL-18 in experimental APAP-induced ALI. Indeed, amelioration of disease as previously observed in IL-18-deficient mice was further substantiated herein by application of the IL-18 opponent IL-18-binding protein (IL-18BPd:Fc) to wild-type mice. Data altogether emphasize crucial pathological action of this cytokine in APAP toxicity. Adding recombinant IL-22 to IL-18BPd:Fc further enhanced protection from liver injury. In contrast to IL-18, the role of prototypic pro-inflammatory IL-1 and tumor necrosis factor-α is controversially discussed with lack of effects or even protective action being repeatedly reported. A prominent detrimental function for IL-18 in APAP-induced ALI as proposed herein should relate to its pivotal role for hepatic expression of interferon-γ and Fas ligand, both of which aggravate APAP toxicity. As IL-18 serum levels increase in patients after APAP overdosing, targeting IL-18 may evolve as novel therapeutic option in those hard-to-treat patients where standard therapy with N-acetylcysteine is unsuccessful. Being a paradigmatic experimental model of ALI, current knowledge on ill-fated properties of IL-18 in APAP intoxication likewise emphasizes the potential of this cytokine to serve as therapeutic target in other entities of inflammatory liver diseases.

Involvement of neutrophils and interleukin-18 in nociception in a mouse model of muscle pain

Muscle pain is a common condition that relates to various pathologies. Muscle overuse induces muscle pain, and neutrophils are key players in pain production. Neutrophils also play a central role in chronic pain by secreting interleukin (IL)-18. The aim of this study was to investigate the involvement of neutrophils and IL-18 in a mouse model of muscle pain. The right hind leg muscles of BALB/c mice were stimulated electrically to induce excessive muscle contraction. The left hind leg muscles were not stimulated. The pressure pain threshold, number of neutrophils, and IL-18 levels were investigated. Furthermore, the effects of the IL-18-binding protein and Brilliant Blue G on pain were investigated. In stimulated muscles, pressure pain thresholds decreased, and neutrophil and IL-18 levels increased compared with that in non-stimulated muscles. The administration of IL-18-binding protein and Brilliant Blue G attenuated hyperalgesia caused by excessive muscle contraction. These results suggest that increased IL-18 secretion from larger numbers of neutrophils elicits mechanical hyperalgesia.