Intermediary quantitative traits--an alternative in the identification of disease genes in asthma?

Expression and Polymorphism of TSLP/TSLP Receptors as Potential Diagnostic Markers of Colorectal Cancer Progression

Colorectal cancer (CRC) is the third most common malignancy and the fourth leading cause of cancer-related mortality worldwide. Inflammation is considered as a critical driver for CRC development and growth. We investigated the association between polymorphisms/expression levels of thymic stromal lymphopoietin (TSLP) /TSLP receptors and CRC risk in Saudi population. DNA samples were isolated from blood samples from 220 participants. Case subjects were 112 patients diagnosed with CRC, while control subjects were 108 healthy individuals, who were not diagnosed with any type of malignancy. We selected two single nucleotide polymorphisms (SNPs) located in the thymic stromal lymphopoietin gene (rs10043985 and rs2289276), three SNPs in TSLP receptor gene (TSLPR; rs36139698, rs36177645, and rs36133495), and two other SNPs in interleukin-7 receptor gene (IL-7R; rs12516866 and rs1053496), and designated these SNPs for a case-control genotyping study. The gene expression was analyzed using quantitative RT-PCR and immunohistochemistry assays array on 20 matching colorectal cancer/normal tissues. mRNA expressions and protein levels of TSLP, TSLPR-α subunit, and IL-7R-α subunit showed a 4-fold increase in colon cancer tissues when compared to normal colon tissues. Furthermore, two SNPs (rs10043985 of TSLP and rs1053496 of IL-7R) showed statistically significant correlations with CRC susceptibility. Interestingly, only rs10043985 showed a statistically significant association (p < 0.0001) in the genotypic and phenotypic levels with CRC for all clinical parameters (age, gender, and tumor location) tested. However, IL-7R rs1053496 genotyping results presented a significant correlation (p < 0.05) in male CRC patients and in individuals under 57 years of age. TSLP rs2289276, IL-7R rs12516866, and all TSLPR variants did not display any significant genotypic or phenotypic correlations in all tested clinical parameters. This study identified that TSLP rs10043985 and IL-7R rs1053496 SNPs, and the expression levels of TSLP and TSLPR-α subunit, can be used as markers for CRC development and treatment. However, additional investigations are required on larger group of patients from diverse ethnicities to confirm the genetic association of these variants to CRC.

Family-based analyses reveal novel genetic overlap between cytokine interleukin-8 and risk for suicide attempt

BACKGROUND

Suicide is major public health concern. It is imperative to find robust biomarkers so that at-risk individuals can be identified in a timely and reliable manner. Previous work suggests mechanistic links between increased cytokines and risk for suicide, but questions remain regarding the etiology of this association, as well as the roles of sex and BMI.

METHODS

Analyses were conducted using a randomly-ascertained extended-pedigree sample of 1882 Mexican-American individuals (60% female, mean age = 42.04, range = 18-97). Genetic correlations were calculated using a variance components approach between the cytokines TNF-α, IL-6 and IL-8, and Lifetime Suicide Attempt and Current Suicidal Ideation. The potentially confounding effects of sex and BMI were considered.

RESULTS

159 individuals endorse a Lifetime Suicide Attempt. IL-8 and IL-6 shared significant genetic overlap with risk for suicide attempt (ρg = 0.49, pFDR = 7.67 × 10-03; ρg = 0.53, pFDR = 0.01), but for IL-6 this was attenuated when BMI was included as a covariate (ρg = 0.37, se = 0.23, pFDR = 0.12). Suicide attempts were significantly more common in females (pFDR = 0.01) and the genetic overlap between IL-8 and risk for suicide attempt was significant in females (ρg = 0.56, pFDR = 0.01), but not in males (ρg = 0.44, pFDR = 0.30).

DISCUSSION

These results demonstrate that: IL-8 shares genetic influences with risk for suicide attempt; females drove this effect; and BMI should be considered when assessing the association between IL-6 and suicide. This finding represents a significant advancement in knowledge by demonstrating that cytokine alterations are not simply a secondary manifestation of suicidal behavior, but rather, the pathophysiology of suicide attempts is, at least partly, underpinned by the same biological mechanisms responsible for regulating inflammatory response.

Airway transcriptomic profiling after bronchial thermoplasty

BACKGROUND

Bronchial thermoplasty is a nonpharmacological, device-based treatment option for a specific population of severe asthmatic subjects, but the underlying mechanisms are largely unknown. The purpose of this study is to identify potential altered pathways by bronchial thermoplasty using a transcriptomic approach.

METHODS

Patients undergoing bronchial thermoplasty were recruited to the study, and a bronchial brushing sample was obtained before each bronchial thermoplasty session and sent for RNA sequencing. A variance component score test was performed to identify those genes whose expression varied after bronchial thermoplasty sessions. Differential gene expression meta-analysis of severe asthmatic subjects versus controls was performed using public repositories. Overlapping genes were included for downstream pathway and network analyses.

RESULTS

12 patients were enrolled in our study. A total of 133 severe asthma cases and 107 healthy controls from the public repositories were included in the meta-analysis. Comparison of differentially expressed genes from our study patients with the public repositories identified eight overlapping genes: AMIGO2, CBX7, NR3C2, SETBP1, SHANK2, SNTB1, STXBP1 and ZNF853. Network analysis of these overlapping genes identified pathways associated with neurophysiological processes.

CONCLUSION

We have shown that bronchial thermoplasty treatment alters several gene networks that are important in asthma pathogenesis. These results potentially elucidate the disease-modifying mechanisms of bronchial thermoplasty and provide several targets for further investigation.

One mechanism of glucocorticoid action in asthma may involve the inhibition of IL-25 expression

While the mechanism of action of classic cytokines in asthma has received increased attention from researchers, certain non-classical cytokines, such as IL-25, also participate in this mechanism. The present study was performed to investigate the changes in IL-25 (IL-17E) mRNA and protein in bronchial asthma and to further characterize the mechanism underlying the action of glucocorticoids in asthma. A total of 96 specific pathogen-free BALB/c male mice were randomly divided into three normal groups (after the first allergization, after the second allergization and after excitation), three asthma groups (with the same three subgroups), a dexamethasone group and a budesonide group (n=12/group). An asthma model was established via the ovalbumin-sensitized excitation method. Mice in the dexamethasone group received intraperitoneal injections of dexamethasone 1 h prior to each excitation, the budesonide group received a budesonide suspension via inhalation 2 h before and after each provocation, and the normal group was sensitized and challenged with isotonic saline. IL-25 protein expression levels in the bronchoalveolar lavage fluid were measured by ELISA, and the relative IL-25 mRNA content in lung tissue was determined by reverse transcription-quantitative polymerase chain reaction. Compared with the normal groups, both the protein and mRNA levels of IL-25 were significantly increased (P<0.05) in the asthma groups. Dexamethasone and budesonide groups exhibited significant protein and mRNA reductions in IL-25, as compared with the asthma group after excitation (P<0.05), whereas these two groups significantly increased levels compared with the normal group after excitation (P<0.05). No significant differences in IL-25 mRNA expression levels were detected in the dexamethasone and budesonide groups when compared with the normal group after excitation. Therefore, we conclude that IL-25 is involved throughout the process of inflammation and inflammatory immune pathogenesis in asthma. One of the mechanisms of glucocorticoid action in asthma may involve inhibition of IL-25 expression.

Genetically engineered Newcastle disease virus expressing human interferon-λ1 induces apoptosis in gastric adenocarcinoma cells and modulates the Th1/Th2 immune response

Interferon-λ1 (IFN-λ1), a recently discovered cytokine of the type III IFN family, was found to be a therapeutic alternative to type I IFN in terms of tumors. Using reverse genetics technique, we generated a recombinant Newcastle disease virus (NDV) LaSota strains named as human IFN‑λ1 recombinant adenovirus (rL-hIFN-λ1) containing human IFN-λ1 gene and further evaluated the expressing of IFN-λ1 in human gastric adenocarcinoma cell line SGC-7901 after infected with rL-hIFN-λ1 by using western blot analysis, RT-PCR and immunofluorescence analyses. IFN-λl specific receptor IFNLR1 was detected on several gastric tumor cell lines including SGC-7901 and AGS and on PBMCs.The expression of the IFN-λ1 proteins reached a high level detected in the supernatant harvested 24 h after the infection of tumor cells. The proliferation changes of SGC infected with rL-hIFN-λ1 was significantly inhibited compared with NDV-infected group. Apoptosis was significantly induced by rL-hIFN-λ1 in gastric cancer cells compared with NDV virus tested by TUNEL assay, western blot analysis and Annexin V flow cytometry. Due to the high dose of IFN-λ1 expressed by the rL-hIFN-λ1-infected tumor cells, the immune study showed that rL-hIFN-λ1 increased IFN-γ production [the T helper cell subtype 1 (Th1) response] and inhibited interleukin (IL)-13 production [the T helper cell subtype 2 (Th2) response] to change the Th1/Th2 response of tumor microenvironment which inhibited tumor growth. This study aims at building recombinant NDV rL-hIFN-λ1 as an efficient antitumor agent.

Upregulated thymic stromal lymphopoietin receptor expression in children with asthma

BACKGROUND

Thymic stromal lymphopoietin (TSLP) plays an important role in pathogenesis in patients with asthma. However, the role of thymic stromal lymphopoietin receptor (TSLPR) and correlation with IL-7Rα and clinical severity in asthmatic or nonasthmatic children remain unclear. We investigated TSLPR and IL-7Rα mRΝΑ levels in asthma and nonasthma and assessed TSLPR expression in children who were sensitive to mites.

MATERIALS AND METHODS

We enrolled asthmatic and nonasthmatic children. To minimize the influence of allergy, we also divided participants into following 4 groups: nonallergic and nonasthmatic group (NN) (healthy children), allergic but nonasthmatic group (AN), nonallergic but asthmatic group (NA) and allergic asthmatic group (AA). We drew blood samples to check total IgE, allergen-specific IgE and TSLP and measured the expression of the TSLPR and IL-7Rα genes using reverse-transcription polymerase chain reaction (RT-PCR) and real-time PCR. Asthma symptom score was also recorded.

RESULTS

Thymic stromal lymphopoietin and TSLPR levels were found to be significantly higher in asthmatic than in nonasthmatic children. The levels of TSLP were found to be significantly different between AA and NN groups (P < 0·05). TSLPR expression in NA and AA groups was found to be significantly higher than in NN group (P < 0·05). TSLPR did not differ significantly between NA and AA groups. The TSLPR expression correlated strongly with IL-7Rα and weakly with mite-specific IgE. Clinical asthmatic severity of children was found to exert no influence on TSLPR level.

CONCLUSION

Thymic stromal lymphopoietin receptor might be a significant disease biomarker for asthma. The levels of TSLPR were found to be higher in asthmatic patients than in healthy children, but were found to be not different between allergic and nonallergic asthmatic patients.