BACKGROUNDNumerous studies have evaluated the association between interleukin-18 (IL-18) promoter gene -607C/ A (rs1946518) polymorphism and tuberculosis (TB) risk. However, the results remain apparently conflicting. The aim of this study was to investigate whether IL-18-607C/A polymorphism is associated with susceptibility to TB.

METHODSPublications addressing the association between the IL-18-607C/A polymorphism and TB risk were selected from the Pubmed, Cochrane Library, Embase, CNKI and Wanfang databases. Data were extracted from the studies by two independent reviewers. Statistical analysis was performed using RevMan 5.0.25 and STATA 11.0 software.

RESULTSEight case-control studies with a total of 1166 TB patients and 1734 controls were retrieved. Meta-analysis results showed significant association between IL-18-607C/A polymorphism and TB risk in all comparisons of the A allele versus C allele (OR=1.17, 95% CI 1.05-1.30, P=0.004), AA versus CC (OR=1.43, 95% CI 1.14-1.81, P=0.002), CA+AA versus CC (OR=1.20, 95% CI 1.01-1.42, P=0.04) and AA versus CA+CC (OR=1.30, 95% CI 1.07-1.58, P=0.007). In subgroup analysis by nationality, a significant association between IL-18-607C/A polymorphism and TB risk in the comparisons of A versus C, CA+AA versus CC and AA versus CA+CC (OR=1.22, 95% CI 1.07-1.38, P=0.002; OR=1.31, 95% CI 1.06-1.61, P=0.01; OR=1.32, 95% CI 1.07-1.63, P=0.01, respectively) were found in Chinese population but not in Indian and Iranian populations.

CONCLUSIONThis study suggests that the -607C/A polymorphism of IL-18 gene would be a risk factor for TB, especially in Chinese population. To further evaluate gene-to-gene and gene-to-environment interactions on -607C/A polymorphism and tuberculosis risk, more studies with thousands of patients are required.

Genetic Predisposition to Disease ; genetics ; Humans ; Interleukin-18 ; genetics ; Promoter Regions, Genetic ; genetics ; Tuberculosis ; epidemiology ; genetics

OBJECTIVETo investigate the association between IL-18 polymorphisms and the risk of unexplained recurrent spontaneous abortion (URSA).

METHODSThe polymorphism of rs187238, rs360718 and rs360717 in IL-18 was determined by PCR in combination with DNA sequencing in 207 patients with URSA and 144 women with normal pregnancy.

RESULTSThe frequency of gene types GG, GC+CC of rs187238 (-137 G/C) in URSA group and control group was 77.3%, 22.7%, and 95.8%, 4.2%, respectively (χ²=22.767, P<0.001). The frequency of allele C in URSA group was significantly higher than that in control groups (13.04% vs 2.1%, χ²=26.102, P<0.001) . The risk of spontaneous abortion in C allele carriers was 7.050 times higher than that in G allele carriers (OR=7.050, 95%CI: 2.990-16.622). No significant difference in genotype frequency and allele frequency of rs360718 and rs360717 polymorphism was noticed between URSA group and control group (χ²=1.497, P=0.221; χ²=0.858, P=0.354).

CONCLUSIONGC+CC genotype and C allele of Rs187238 in IL-18 gene are associated with the susceptibility of recurrent spontaneous miscarriage. Rs360718 and rs360717 in IL-18 may not be associated with URSA.

Abortion, Habitual ; genetics ; Adult ; Female ; Genetic Predisposition to Disease ; Humans ; Interleukin-18 ; genetics ; Polymorphism, Genetic ; Young Adult

This study aimed to investigate the intervention effect and mechanism of Xiaoyao Kangai Jieyu Recipe(XKJR) on hip-pocampal microglia and neuronal damage in mice with breast cancer related depression. The mouse model of breast cancer related depression was established by inoculation of 4T1 breast cancer cells in axilla and subcutaneous injection of corticosterone(30 mg·kg~(-1)). The successfully modeled mice were randomly divided into a model group, a positive drug group(capecitabine 60 mg·kg~(-1)+fluoxetine 19.5 mg·kg~(-1)), and XKJR group(19.5 mg·kg~(-1) crude drug), with 6 in each group. Another 6 normal mice were taken as a normal group. The administration groups were given corresponding drugs by gavage, while the normal and model groups were given an equal volume of distilled water, once a day for 21 consecutive days. The depressive behavior of mice was assessed by glucose consumption test, open field test and novelty-suppressed feeding test. Hematoxylin and eosin(HE) staining and tumor suppression rate were used to evaluate the changes of axillary tumors. The mRNA expressions and the relative protein expressions of interleukin-1β(IL-1β), interleukin-18(IL-18), cyclooxyganese-2(COX-2) and glutamyl-prolyl-tRNA synthetase(EPRs) in the hippocampus of mice were determined by quantitative real-time polymerase chain reaction(qRT-PCR) and immunohistochemistry, respectively. Immunofluorescence was performed to detect the mean fluorescence intensity of CD11b, a marker of hippocampal microglia activation. Nissler staining and transmission electron microscopy were employed to observe the morphological changes and the ultramorphological changes of hippocampal neurons, respectively. The experimental results indicated that compared with the normal group, the model group had reduced glucose consumption and lowered number of total activities in open field test(P<0.05, P<0.01), prolonged first feeding latency in no-velty-suppressed feeding test(P<0.01), and significant depression-like behavior; the contents of IL-1β, IL-18, COX-2, and EPRs in hippocampus were increased(P<0.05, P<0.01), with hippocampal microglia activation and obvious neuronal damage. Compared with the model group, the positive drug group and the XKJR group presented an improvement in depressive behaviors, a decrease in the contents of IL-1β, IL-18, COX-2 and EPRs in hippocampus, and an alleviation in the activation of hippocampal microglia and neuronal damage; the tumor suppression rates of positive drug and XKJR were 40.32% and 48.83%, respectively, suggesting a lower tumor growth rate than that of the model group. In summary, XKJR may improve hippocampal microglia activation and neuronal damage in mice with breast cancer related depression through activating COX signaling pathway.
Mice ; Animals ; Depression/genetics* ; Interleukin-18 ; Cyclooxygenase 2/genetics* ; Hippocampus ; Glucose ; Neoplasms

The porcine IL-18 gene was amplified from recombinant plasmid pGEM-IL-18 by PCR, then the pPIC9K-IL-18 of fusion expression vector was constructed by inserting IL-18 fragment,and was transformed to GS115 by electroporation, multi-copy recombinant strains were screened by G418. The expression of recombinant fusion protein was induced by methanol, SDS-PAGE was used to analyze expression product, fusion protein was purified by Sephadex G-100 column, bioactivity of IL-18 was measured by MTT assays. Experiment results show fusion protein of pIL-18 secreted by GS115,expression reaches the secretion peak of 160 mg/L at 72 h. We have expressed and purified successfully the recombinant pIL-18 with obvious biological activity in Pichia pastoris.
Animals ; Electrophoresis, Polyacrylamide Gel ; Electroporation ; Interleukin-18 ; biosynthesis ; genetics ; Pichia ; genetics ; metabolism ; Recombinant Fusion Proteins ; analysis ; biosynthesis ; genetics ; Swine

OBJECTIVETo investigate serum IL-18 levels in mice with collagen-induced arthritis treated by recombinant adenoviral vector containing mIL-18BP and mIL-4 fusion gene (AdmIL-18BP/mIL-4).

METHODSArthritis was induced by injection of collagen in male DBA-1/BOM mice. Mice with collagen-induced arthritis (CIA) were intra-articularly injected with 10(7)pfu/6μL of AdmIL-18BP/mIL-4; and in mice of control groups AdLacZ or PBS were used. The animals were sacrificed at week 1, 2 and 4 after treatment. Serum IL-18 levels were determined by ELISA at the different time points.

RESULTThe mean serum levels of IL-18 at weeks 1, 2, and 4 after injection of AdmIL-18BP/mIL-4 were (36.5±5.4)ng/L, (32.5 ± 3.2) ng/L and (28.7 ±2.9)ng/L, respectively, which were significantly lower than those at the same time point of AdLacZ group [(66.2 ±5.1)ng/L, (69.2 ±4.2)ng/L and (77.7 ±3.9)ng/L] and PBS group [(67.3 ±7.1)ng/L, (71.9 ±1.8)ng/L and (78.7±4.1)ng/L] (P<0.01 at all time points). In the therapy group, there were no significant differences in the mean serum concentrations of IL-18 at all time points.

CONCLUSIONThe serum IL-18 levels in CIA mice are down-regulated by treatment of recombinant adenovirus containing mIL-18BP and mIL-4 fuse gene, which might be a promising therapeutic strategy for rheumatoid arthritis.

Adenoviridae ; genetics ; Animals ; Arthritis, Experimental ; blood ; therapy ; Gene Fusion ; Genetic Therapy ; Genetic Vectors ; Interleukin-18 ; blood ; genetics ; Interleukin-4 ; genetics ; Male ; Mice ; Mice, Inbred DBA

OBJECTIVEThe expressions of caspase-1 and cytokines activated by caspase-1 are associated with the pathophysiology of many diseases for its proinflammatory and proapototic peculiarity. However its relationship to brain injury of developing rats following recurrent seizures has not yet been identified. This study aimed to investigate the role of caspase-1 and cytokines activated by caspase-1 in brain injury of developing rats following recurrent seizures.

METHODSA total of 96 postnatal 20 day Sprague-Dawley rats were randomly assigned into Control and Seizure groups. Seizures were induced in the Seizure group by flurothyl inhalation daily for six days. Brain tissues were sampled at 6 hrs, and at 1, 3, and 7 days after last seizure. The expressions of caspase-1, interleukin (IL)-18 and IL-1beta mRNA in the cerebral cortex were detected by RT-PCR. The water content of the brain and the pathological changes of cortex nerve cells were observed. Brain injury was evaluated using a semiquantitative neuropathological scoring system.

RESULTSThe levels of caspase-1 and IL-18 mRNA in the cerebral cortex of the Seizure group were obviously higher than those in the Control group at 6 hrs, and at 1, 3, and 7 days after seizure (P < 0.05 or P < 0.01). The expression of IL-1beta mRNA in the Seizure group exhibited a biphasic pattern: increased significantly at 6 hrs, and at 1 and 7 days post-seizure (P < 0.01), but was not significantly different from the Control group at 3 days post-seizure. Edema, degeneration and necrosis of nerve cells in cerebral cortex, accompanying by inflammatory cell infiltration and apoptosis of nerve cells, were observed under a light microscope in the Seizure group after recurrent seizures. The water content of the brain in the Seizure group increased significantly compared with that in the Control group at 6 hrs, and at 1 and 3 days after recurrent seizures (P < 0.01). The Seizure group had significantly higher neuropathological scores than the Control group at each time point (P < 0.01).

CONCLUSIONSCaspase-1 and cytokines activated by caspase-1 play an important role in the developing brain injury after recurrent seizures.

Animals ; Brain ; pathology ; Caspase 1 ; genetics ; physiology ; Female ; Interleukin-1 ; genetics ; physiology ; Interleukin-18 ; genetics ; physiology ; Male ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Recurrence ; Seizures ; pathology

IL-18, as a polyphonic cytokine, is important in immune response and physiologic function. We designed one pair of primers, amplified the porcine IL-18 gene fused with a C-terminal 6xHistidine tag, and then subcloned into the pFastBacDual of Baculovirus transfer vector and transformed into DH10Bac containing a shuttle vector of Bacmid. After co-transfecting the recombinant plasmid into insect cells, the 18 kDa expressed protein of porcine IL-18 was detected by SDS-PAGE; the specificity of expressed protein was confirmed by Western blotting. The purified porcine IL-18 protein induced obvious proliferation of porcine T lymphocytes in vitro, which indicated that the expression of IL-18 had high biological activity.
Animals ; Baculoviridae ; genetics ; metabolism ; Cells, Cultured ; Genetic Vectors ; genetics ; Insecta ; genetics ; metabolism ; Interleukin-18 ; biosynthesis ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; immunology ; Swine ; Transfection

BACKGROUND: As a potent pro-inflammatory cytokine of the interleukin (IL)-1 family, IL-18 was elevated in early active and progressive plaque-type psoriatic lesions and that serum or plasma levels of IL-18 correlated with the Psoriasis Area and Severity Index (PASI). Although results from previous studies have established that IL-18 may aggravate psoriatic inflammation, the mechanisms of this process remain unknown. In this study, IL-18 knock out (KO) mice and wild-type (WT) mice were used to investigate the effects of IL-18 within a mouse model of psoriasis. METHODS: WT and IL-18 KO mice were divided into four groups, including imiquimod (IMQ)-treated IL-18 KO group (n = 11) and WT group (n = 13) as well as their respectively gene-matched control mice (receiving vaseline; n = 12). PASI scores were used to evaluate psoriatic lesions in IMQ-treated mice. Pathological features and dermal cellular infiltration were investigated by hematoxylin and eosin staining. The levels of psoriasis-related cytokines including IL-23, IL-17, IL-12, IL-1β, IFNγ, IL-15, IL-27, and IL-4 were tested by real-time polymerase chain reaction (PCR). The protein level of IL-1β, IL-27, CXCL1, and Ly6 g were investigated by immunohistochemistry (IHC). RESULTS: Acanthosis (98.46 ± 14.12 vs. 222.68 ± 71.10 μm, P < 0.01) and dermal cell infiltration (572.25 ± 47.45 vs. 762.47 ± 59.59 cells/field, P < 0.01) were significantly milder in IMQ-induced IL-18 KO mice compared with that in WT mice. IMQ-induced IL-18 KO mice manifested larger areas of Munro microabscesses (11,467.83 ± 5112.09 vs. 4093.19 ± 2591.88 μm, P < 0.01) and scales (100,935.24 ± 41,167.77 vs. 41,604.41 ± 14,184.10 μm, P < 0.01) as compared with WT mice. In skin lesions of IL-18 KO mice, the expressions of IL-1β, IL-4, and IL-27 were all significantly upregulated but IL-17 was decreased. Histologically, strong positive signals of Ly6g were observed within the epidermis of IL-18 KO mice but expressions of CXCL1 were decreased. CONCLUSIONS IL-18 may exacerbate prominent inflammation and influence pathological features in IMQ-induced mouse model of psoriasis. IL-18 may upregulate pro-inflammatory cytokines and reduce protective cytokines, thus aggravating psoriatic inflammation. In addition, IL-18 may be involved in the formation of Munro microabscesses and scales.
Animals ; Chemokine CXCL1 ; metabolism ; Cytokines ; metabolism ; Disease Models, Animal ; Imiquimod ; toxicity ; Interleukin-17 ; metabolism ; Interleukin-18 ; metabolism ; Mice ; Mice, Knockout ; Psoriasis ; chemically induced ; genetics ; metabolism ; Skin ; immunology ; metabolism

The NLRP3 inflammasome, a protein complex belonging to the family of nucleotide-binding and oligomerization domain like receptors (NLRs), plays a vital role in the innate immune system. It promotes pro-caspase 1 cleavage into active caspase-1, which contributes to maturation and releases of IL-1β and IL-18 in response to the harmful signals and participates in the host immune response and sterile inflammation. Recently a large number of studies have shown that NLRP3 inflammasome closely relates to the pathogenesis of the vascular diseases. NLRP3 inflammasome, which involves in the sterile inflammation of the vascular wall, plays an important role in the pathogenesis of main, middle and small arteries.
Caspase 1 ; immunology ; metabolism ; Gene Expression Regulation ; genetics ; immunology ; Humans ; Inflammasomes ; immunology ; Inflammation ; complications ; genetics ; Interleukin-18 ; genetics ; immunology ; Interleukin-1beta ; genetics ; immunology ; NLR Family, Pyrin Domain-Containing 3 Protein ; immunology ; Signal Transduction ; genetics ; immunology ; Vascular Diseases ; etiology ; genetics ; immunology

Porcine interleukin-18 mature protein gene was amplified from porcine spleen cells by RT-PCR. PCR product was cloned into the T vector pGEM-T for sequencing. The nucleotide sequence of this gene was 474 bp. Then, it was subcloned into the prokaryotic expressing plasmid vector pGEX6P-1 and transformed into host E. coli strain BL21 for expression. The expression of pIL-18 mature protein gene was identified by SDS-PAGE .The expression product was fusion protein with molecular weight of 45 kD and the percentage of expression protein in E. coil protein was 28%. The protein was purified by washing of inclusion bodies and the activity was measured by methyl thiazolyl tetrazolium (MTT).
Amino Acid Sequence ; Animals ; Base Sequence ; Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Interleukin-18 ; biosynthesis ; genetics ; Molecular Sequence Data ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; immunology ; Swine