Eosinophilic inflammation: mechanisms regulating IL-5 transcription in human T lymphocytes

TGF-β gene polimorphisms as risk factors for asthma control among clinic patients

BACKGROUND

TGF-β and its receptors play a crucial role in asthma pathogenesis, bronchial hyperreactivity, and bronchial remodeling. Expression of isoforms 1-3 of TGFβ cytokine is influenced by tagging polymorphisms in the TGFβ1, TGFβ2 and TGFβ3 gene, and these SNPs may be associated with the risk of asthma development and severity as well as with other diseases. Polymorphic forms of TGF-β1, TGF-β2 and TGF-β3 genes regulate the degree of bronchial inflammation, deterioration of lung functional parameters in spirometry and elevated level of total IgE. All this results in intensification of disease symptoms. According to current GINA 2020 guidelines, the Asthma Control Test (ACT™) should be applied to assess asthma symptoms.

METHODS

An analysis of polymorphisms localized in TGF-β1, TGF-β2 and TGF-β3 genes was conducted on 652 DNA samples with an application of the MassARRAY® system using the mass spectrometry technique MALDI TOF MS. The degree of asthma control was evaluated with ACT™.

RESULTS

The occurrence of the T / C genotype in rs8109627 (p = 0.0171) in the TGF-β1 gene is significantly associated with a higher ACT result (controlled asthma) in a multivariate linear regression analysis model after using backward stepwise selection of variables. In addition, in the linear model for prediction of ACT score we showed SNP rs8109627 (p = 0.0497) in the TGF-β1 gene (improvement of the disease control - controlled asthma) and rs2796822 (p = 0.0454) in the TGF-β2 gene (deterioration of the diseases control - uncontrolled asthma) significantly modify the degree of asthma control.

DISCUSSION

We described clinical significance of two SNPs in two genes TGF-β1 and TGF-β2, as yet unknown. We proved that the use of both genotypes and MAC allows to create a moderately correct prognostic model which is about 70% efficient on the entire set of analyzed SNPs in TGF-β1, TGF-β2, and TGF-β3 genes.

Bilirubin prevents acute DSS-induced colitis by inhibiting leukocyte infiltration and suppressing upregulation of inducible nitric oxide synthase

Bilirubin is thought to exert anti-inflammatory effects by inhibiting vascular cell adhesion molecule-1 (VCAM-1)-dependent leukocyte migration and by suppressing the expression of inducible nitric oxide synthase (iNOS). As VCAM-1 and iNOS are important mediators of tissue injury in the dextran sodium sulfate (DSS) murine model of inflammatory colitis, we examined whether bilirubin prevents colonic injury in DSS-treated mice. Male C57BL/6 mice were administered 2.5% DSS in the drinking water for 7 days, while simultaneously receiving intraperitoneal injections of bilirubin (30 mg/kg) or potassium phosphate vehicle. Disease activity was monitored, peripheral blood counts and serum nitrate levels were determined, and intestinal specimens were analyzed for histological injury, leukocyte infiltration, and iNOS expression. The effect of bilirubin on IL-5 production by HSB-2 cells and on Jurkat cell transendothelial migration also was determined. DSS-treated mice that simultaneously received bilirubin lost less body weight, had lower serum nitrate levels, and exhibited reduced disease severity than vehicle-treated animals. Concordantly, histopathological analyses revealed that bilirubin-treated mice manifested significantly less colonic injury, including reduced infiltration of eosinophils, lymphocytes, and monocytes, and diminished iNOS expression. Bilirubin administration also was associated with decreased eosinophil and monocyte infiltration into the small intestine, with a corresponding increase in peripheral blood eosinophilia. Bilirubin prevented Jurkat migration but did not alter IL-5 production. In conclusion, bilirubin prevents DSS-induced colitis by inhibiting the migration of leukocytes across the vascular endothelium and by suppressing iNOS expression.

Role of Ets Proteins in Development, Differentiation, and Function of T-Cell Subsets

Through positive selection, double-positive cells in the thymus differentiate into CD4(+) or CD8(+) T single-positive cells that subsequently develop into different types of effective T cells, such as T-helper and cytotoxic T lymphocyte cells, that play distinctive roles in the immune system. Development, differentiation, and function of thymocytes and CD4(+) and CD8(+) T cells are controlled by a multitude of secreted and intracellular factors, ranging from cytokine signaling modules to transcription factors and epigenetic modifiers. Members of the E26 transformation specific (Ets) family of transcription factors, in particular, are potent regulators of these CD4(+) or CD8(+) T-cell processes. In this review, we summarize and discuss the functions and underlying mechanisms of the Ets family members that have been characterized as involved in these processes. Ongoing research of these factors is expected to identify practical applications for the Ets family members as novel therapeutic targets for inflammation-related diseases.

Identification and association of the single nucleotide polymorphisms, C-509T, C+466T and T+869C, of the TGF-β1 gene in patients with asthma and their influence on the mRNA expression level of TGF-β1

Transforming growth factor-β1 (TGF-β1) is an important fibrogenic and immunomodulatory cytokine participating in the pathogenesis of a number of illnesses related to the growth, differentiation and migration of cells. It also plays a key role in inflammation, atherosclerosis, vascular inflammation and asthma. The aim of the present study was to evaluate the association between the expression of the TGF-β1 gene and its genetic polymorphisms, and the disease phenotype. The study comprised 173 patients with asthma, as well as 163 healthy volunteers as a control group. The gender profiles of the groups were similar (p=0.8415). Genotyping was performed by polymerase chain reaction (PCR)-high resolution melting (HRM). The results were verified by sequencing. Gene expression was evaluated by RT-PCR. This study evaluated the role and frequency of genetic polymorphisms (C−509T, C+466T and T+869C) of the TGF-β1 gene in the study group (patients with asthma) and the control group (healthy volunteers). The results obtained for the patients and healthy controls were as follows: C−509T single nucleotide polymorphism (SNP) (controls, TT/CT/CC-0.4444/0.5309/0.0247; patients, TT/CT/CC-0.3699/0.6012/0.0289), C+466T SNP (controls, TT/CT/CC-1.000/0.000/0.000; patients, TT/CT/CC-1.000/0.000/0.000) and T+869C SNP (controls, TT/CT/CC-1.000/0.000/0.000; patients, TT/CT/CC-1.000/0.000/0.000). Only the C−509T polymorphism was found to play a significant role in the pathogenesis of asthma, as well as a risk factor in the loss of the clinical control of the disease [TT vs. CC/CT, odds ratio (OR) 2.38; confidence interval (CI) 1.22–4.66; p=0.0103]. A significant difference was noted between the study and control groups with regard to the mRNA expression of TGF-β1 (p=0.0133). A higher level of expression of the TGF-β1 gene correlated with the time of diagnosis of patients over 16 years of age (p=0.0255). This study demonstrates that the C−509T SNP is a significant clinical risk factor for asthma and that the TGF-β1 cytokine contributes to the progression of the illness.

A retrospective cross-sectional study of risk factors and clinical spectrum of children admitted to hospital with pandemic H1N1 influenza as compared to influenza A

OBJECTIVE

To compare risk factors for severe disease as measured by admission to hospital and intensive care unit (ICU) and other clinical outcomes in children with pandemic H1N1 (pH1N1) versus those with seasonal influenza.

DESIGN

Retrospective analysis of children admitted to hospital with pH1N1 versus seasonal influenza A.

SETTING

Canadian tertiary referral children's hospital.

PARTICIPANTS

All laboratory-identified cases of pH1N1 in children younger than 18 years admitted to hospital in 2009 (n=176) and all seasonal influenza A cases admitted to hospital from influenza seasons 2004-2005 to 2008-2009 (n=200). Children with onset of symptoms more than 3 days after admission were excluded.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcomes include admission to hospital and ICU and need for mechanical ventilation. Secondary outcomes include length of stay in hospital and duration of supplemental oxygen requirement.

RESULTS

Children admitted with pH1N1 were older than seasonal influenza A admissions (hospital admission: 6.5 vs 3.3 years, p<0.01; ICU admission: 7.3 vs 3.6 years, p=0.02). Children hospitalised with pH1N1 were more likely to have a pre-existing diagnosis of asthma (15% vs 5%, p<0.01); however, there was no difference in the severity of pre-existing asthma between the two groups. After controlling for obesity, asthma (OR 4.59, 95% CI 1.42 to 14.81) and age ≥5 years (OR 2.87, 95% CI 1.60 to 5.16) were more common risk factors in admitted children with pH1N1. Asthma was a significant predictor of the need for intensive care in patients with pH1N1 (OR 4.56, 95% CI 1.16 to 17.89) but not in patients with seasonal influenza A.

CONCLUSION

While most pH1N1 cases presented with classic influenza-like symptoms, risk factors for severe pH1N1 disease differed from seasonal influenza A. Older age and asthma were associated with increased admission to hospital and ICU for children with pH1N1.

Phylogenetic and functional analysis identifies Ets-1 as a novel regulator of the Th2 cytokine gene locus

The Th2 cytokine gene locus has emerged as a remarkable example of coordinated gene expression, the regulation of which seems to be rooted in an extensive array of cis-regulatory regions. Using a hypothesis-generating computational approach that integrated multispecies (n = 11) sequence comparisons with algorithm-based transcription factor binding-site predictions, we sought to identify evolutionarily conserved noncoding regions (ECRs) and motifs shared among them, which may underlie coregulation. Twenty-two transcription factor families were predicted to have binding sites in at least two Th2 ECRs. The ranking of these shared motifs according to their distribution and relative frequency pointed to a regulatory hierarchy among the transcription factor families. GATA sites were the most prevalent and widely distributed, consistent with the known role of GATA3 as a Th2 master switch. Unexpectedly, sites for ETS-domain proteins were also predicted within several Th2 ECRs and the majority of these sites were found to support Ets-1 binding in vitro and in vivo. Of note, the expression of all three Th2 cytokines (IL-5, -13, and -4) was significantly and selectively decreased in Th2 cells generated from Ets-1-deficient mice. Collectively, these data suggest that Ets-1 contributes to Th2 cytokine gene regulation by interacting with multiple cis-regulatory regions throughout the Th2 locus.

Functional characterization of an eosinophil-specific galectin, ovine galectin-14

Across mammalian species, human galectin-10 and ovine galectin-14 are unique in their expression in eosinophils and their release into lung and gastrointestinal tissues following allergen or parasite challenge. Recombinant galectin-14 is active in carbohydrate binding assays and has been used in this study to unravel the function of this major eosinophil constituent. In vitro cultures revealed that galectin-14 is spontaneously released by eosinophils isolated from allergen-stimulated mammary gland lavage, but not by resting peripheral blood eosinophils. Galectin-14 secretion from peripheral blood eosinophils can be induced by the same stimuli that induce eosinophil degranulation. Flow cytometric analysis showed that recombinant galectin-14 can bind in vitro to eosinophils, neutrophils and activated lymphocytes. Glycan array screening indicated that galectin-14 recognizes terminal N-acetyllactosamine residues which can be modified with alpha1-2-fucosylation and, uniquely for a galectin, prefers alpha2- over alpha2-sialylation. Galectin-14 showed the greatest affinity for lacto-N-neotetraose, an immunomodulatory oligosaccharide expressed by helminths. Galectin-14 binds specifically to laminin in vitro, and to mucus and mucus producing cells on lung and intestinal tissue sections. In vivo, galectin-14 is abundantly present in mucus scrapings collected from either lungs or gastrointestinal tract following allergen or parasite challenge, respectively. These results suggest that in vivo secretion of eosinophil galectins may be specifically induced at epithelial surfaces after recruitment of eosinophils by allergic stimuli, and that eosinophil galectins may be involved in promoting adhesion and changing mucus properties during parasite infection and allergies.