Beáta Szebeni

Increased mucosal expression of toll-like receptor (TLR)2 and TLR4 in coeliac disease

Objectives: The dysregulation of adaptive immunity is extensively investigated in celiac disease (CD). Recent data also suggest, however, the implication of innate immunity in CD. Toll-like receptors (TLRs) play a central role in the initiation or maintenance of innate immune responses. The aim of this study was to characterise the expression of TLR2, TLR3, and TLR4 in duodenal biopsy samples taken from children with CD and from controls. Patients and Methods: Duodenal biopsy specimens were collected from 16 children with untreated CD, 9 children with treated CD, and 10 controls. The mRNA expression of TLR2, TLR3, and TLR4 was determined by semiquantitative reverse transcription-polymerase chain reaction. Protein levels of TLRs were determined by Western blot. Results: We found higher TLR2 and TLR4 mRNA expression and protein levels in the duodenal mucosa of children with treated CD and untreated CD compared with controls. TLR2 and TLR4 mRNA expression and protein levels were even higher in the duodenal mucosa of children with treated CD than in untreated CD. TLR3 mRNA expression was increased in the duodenal mucosa of children with treated CD compared with untreated CD and controls. We were able to detect TLR3 protein only in the biopsy specimens of treated patients with CD. Conclusions: The alteration of TLR2 and TLR4 expression in the duodenal mucosa of patients with CD supports the potential implication of innate immune system in the pathomechanism of this disease.

Heat shock protein 72 (HSPA1B) gene polymorphism and Toll-like receptor (TLR) 4 mutation are associated with increased risk of urinary tract infection in children.

Innate immunity and urinary tract response play a central role in the development of urinary tract infection (UTI). Heat shock protein (HSP) 72 and Toll-like receptor (TLR) 4 are among the key elements of innate defence mechanisms. This study assesses the role of HSPA1B A(1267)G and TLR4 A(896)G polymorphisms using allele-specific polymerase chain reaction in 103 patients treated with recurrent UTI. Allelic prevalence was compared with reference values of 235 healthy controls. Clinical data were also statistically evaluated. TLR4 (896)AG genotype and TLR4 (896)G allele had also higher prevalence in UTI patients versus controls (p = 0.031 and 0.041, respectively). Our data indicates a relationship between the carrier status of HSPA1B (1267)G and TLR4 (896)G alleles and the development of recurrent UTI in childhood independently of other renal abnormalities, while raising further questions about the clinical and therapeutic relevance of these polymorphisms in everyday pediatric nephrology.

Genetic polymorphisms of CD14, toll-like receptor 4, and caspase-recruitment domain 15 are not associated with necrotizing enterocolitis in very low birth weight infants.

Objectives: Inadequate response of the innate immune system to bacterial antigens present in the intestinal flora may play a role in the development of necrotizing enterocolitis (NEC). Pattern recognition receptors such as CD14, toll-like receptor (TLR) 4, and caspase-recruitment domain (CARD) 15 bind bacterial lipopolysaccharide and peptidoglycan, and their activation leads to production of inflammatory cytokines. Our aim was to evaluate whether single nucleotide polymorphisms (SNPs) of CD14, TLR4, and CARD15 are associated with the risk of NEC in very low birth weight (VLBW) infants. Patients and Methods: We determined the CD14 C−260T, TLR4 A + 896G, C + 1196T, and CARD15 G + 2722C, C + 2104T, 3020insC functional SNPs in dried blood samples from 118 VLBW infants (of those, 41 developed NEC) and from 146 healthy term newborns using polymerase chain reaction and restriction fragment length polymorphism methods. We tested the association between genotype and risk of NEC. Results: No significant differences were found in the prevalence of CD14 −260T, TLR4 +896G, +1196T, and CARD15 +2722C, +2104T, 3020insC alleles between VLBW infants and healthy term newborns (P = NS). The frequencies of investigated genotypes were similar in infants with and without NEC (P = NS). Furthermore, we did not find any association between genotype and prematurity or sepsis, which are important risk factors of NEC. Conclusions: Carrier state of the tested CD14, TLR4, and CARD15 SNPs is not associated with NEC risk in VLBW infants.

Intestinal alkaline phosphatase in the colonic mucosa of children with inflammatory bowel disease

AIM To investigate intestinal alkaline phosphatase (iAP) in the intestinal mucosa of children with inflammatory bowel disease (IBD). METHODS Colonic biopsy samples were taken from 15 newly diagnosed IBD patients and from 10 healthy controls. In IBD patients, specimens were obtained both from inflamed and non-inflamed areas. The iAP mRNA and protein expression was determined by reverse transcription-polymerase chain reaction and Western blotting analysis, respectively. Tissue localization of iAP and Toll-like receptor (TLR) 4 was investigated by immunofluorescent staining. RESULTS The iAP protein level in the inflamed mucosa of children with Crohns disease (CD) and ulcerative colitis (UC) was significantly decreased when compared with controls (both P < 0.05). Similarly, we found a significantly decreased level of iAP protein in the inflamed mucosa in CD compared with non-inflamed mucosa in CD (P < 0.05). In addition, the iAP protein level in inflamed colonic mucosa in patients with UC was decreased compared with non-inflamed mucosa in patients with CD (P < 0.05). iAP protein levels in the non-inflamed mucosa of patients with CD were similar to controls. iAP mRNA expression in inflamed colonic mucosa of children with CD and UC was not significantly different from that in non-inflamed colonic mucosa with CD. Expression of iAP mRNA in patients with non-inflamed mucosa and in controls were similar. Co-localization of iAP with TLR4 showed intense staining with a dotted-like pattern. iAP was present in the inflamed and non-inflamed mucosa of patients with CD, UC, and in control biopsy specimens, irrespective of whether it was present in the terminal ileum or in the colon. However, the fluorescent signal of TLR4 was more pronounced in the colon compared with the terminal ileum in all groups studied. CONCLUSION Lower than normal iAP protein levels in inflamed mucosa of IBD patients may indicate a role for iAP in inflammatory lesions in IBD. Based on our results, administration of exogenous iAP enzyme to patients with the active form of IBD may be a therapeutic option.

Genetic polymorphisms of vascular endothelial growth factor and angiopoietin 2 in retinopathy of prematurity.

Angiogenic factors such as vascular endothelial growth factor (VEGF) and angiopoietin 2 (Ang2) contribute to development of retinopathy of prematurity (ROP). We aimed to test whether polymorphisms of these factors are associated with ROP. VEGF− 2578 and Ang2− 35 polymorphisms were analyzed with PCR-RFLP method in 200 preterm infants without ROP or with ROP stages 1–5. Our results suggest that there is no association between carrier state of VEGF− 2578 and Ang2− 35 and risk of ROP in preterm infants. The prevalence of VEGF− 2578 “A” allele was lower in preterm boys with severe ROP (stages 4–5) than in those without or with mild ROP (stages 1–3).

Frequencies of genetic polymorphisms of TLR4 and CD14 and of HLA-DQ genotypes in children with celiac disease, type 1 diabetes mellitus, or both

Objectives: Besides the central role of the adaptive immune system, a disturbance of innate immunity is also involved in the pathogenesis of celiac disease (CD). Inasmuch as CD and type 1 diabetes mellitus (T1DM) frequently coexist because of a common genetic predisposition, our aim was to study the frequency of CD14 C-260T and TLR4 A+896G single nucleotide polymorphisms (SNPs) and the distribution of HLA-DQ genotypes in children affected by CD, T1DM, or both. Patients and Methods: TLR4 and CD14 SNPs were tested by polymerase chain reaction, followed by restriction fragment length polymorphism analysis in 80 children with T1DM, 100 children with CD, and 47 children with both CD and T1DM. Determination of HLA-DQ alleles was done by sequence-specific polymerase chain reaction. Frequencies were compared with those of healthy control children. Results: The prevalence of the homozygous CD14 C-260TT genotype was significantly (P = 0.0081) lower in children with T1DM but not in those with CD and T1DM, compared with control children. No difference was found in the genotype and allele frequencies of TLR4 between the studied groups. In patients with T1DM, the frequency of the homozygous HLA-DQ8 genotype was significantly higher than in CD, whereas the frequency of homozygous or heterozygous HLA-DQ2 genotypes did not differ from that in control children. In patients with CD, both homozygous and heterozygous HLA-DQ2 genotypes were significantly more frequent than in the control and T1DM groups, and no elevation in the frequency of the HLA-DQ8 genotypes was observed. In patients with T1DM and those with CD and T1DM, the occurrence of HLA-DQ2/8 heterozygosity was significantly higher than in children with CD only and in control children. Conclusions: Our results suggest that in patients with T1DM, the CD14 C-260TT homozygous genotype increases the risk for the development of CD. The distribution of HLA-DQ genotype is different in children with CD and T1DM than in children with CD or T1DM only. Determination of the HLA-DQ genotype in children with T1DM may help in estimating the risk for the development of CD.

Galectin-9 in allergic airway inflammation and hyper-responsiveness in mice.

Background: Galectin-9 (Gal-9) is a member of the growing family of β-galactoside-binding lectins. Gal-9 is an eosinophil chemoattractant and inducer of Th1 cell apoptosis. These effects suggest its potential role in the pathogenesis of asthma. Our aim was to study the expression of Gal-9 in an ovalbumin (OVA)-induced mouse model of allergic asthma. Methods: To investigate the significance of Gal-9 in allergic inflammation and airway hyperresponsiveness (AHR), a group of BALB/c mice was sensitized and challenged with OVA (GOVA). Another group of animals was allergized with OVA and also treated with dexamethasone (DEX) (GOVA+DEX). The control group (GPBS) received phosphate-buffered saline instead of OVA as placebo. Airway reactivity to intravenous methacholine was assessed. Results: The percentage of Gal-9-positive cells and their intracellular Gal-9 content and Th1/Th2 cytokine levels in the bronchoalveolar lavage (BAL) were determined by flow cytometry. Gal-9 mRNA expression and protein level were measured in the lung tissue by real-time RT-PCR and Western blot. In GOVA mice, airway inflammation and mucus hypersecretion developed. DEX treatment inhibited the main features of experimental asthma. The number of Gal-9-positive lymphocytes, eosinophil and neutrophil granulocytes and the levels of Th2 cytokines were higher in the BAL of GOVA compared to GPBS or GOVA+DEX mice. Moreover, Gal-9 protein level was elevated in the lungs of GOVA mice. Conclusions: These results suggest that Gal-9 plays a role as a mediator contributing to the development of allergic airway inflammation. Gal-9 may serve as a recruiter of eosinophil granulocytes and promoter of Th2 dominance.

Increased expression of hypoxia-inducible factor 1alpha in coeliac disease.

Previously, it has been suggested that hypoxia-inducible factor (HIF) 1 signaling may play determinative role in the maintenance of the barrier function of the intestinal epithelium in inflammatory bowel disease. Our aim was to depict the alteration of HIF-1alpha and related genes in celiac disease (CD) where the importance of the barrier function is well known. Duodenal biopsy specimens were collected from 16 children with untreated CD, 9 children with treated CD and 10 controls. HIF-1alpha, trefoil factor 1 (TFF1), ecto-5-prime nucleotidase (CD73), and multi drug resistance gene 1 (MDR1) mRNA and HIF-1alpha protein expression were determined by real-time PCR and Western blot, respectively. Localization of HIF-1alpha was determined by immunofluorescent staining. We found increased HIF-1alpha and TFF1 mRNA and HIF-1alpha protein expression in the duodenal mucosa of children with untreated CD compared with controls or children with treated CD (p < 0.05). In untreated CD children, HIF-1alpha staining was present in cytoplasmic and nuclear region of the villous enterocytes. In treated CD mRNA expression of CD73 and MDR1 were increased compared with controls (p < 0.01 and 0.05, respectively). Our results of increased mucosal HIF-1alpha expression in CD children suggest the contribution of this signaling pathway in the pathomechanism of CD.

Role of serum and glucocorticoid-regulated kinase-1 in the protective effects of erythropoietin during renal ischemia/reperfusion injury

Erythropoietin (EPO) protects the kidneys from ischemia/reperfusion (I/R) injury; however, the exact signalling mechanisms are not fully understood. The serum and glucocorticoid-regulated kinase 1 (SGK1) is an anti-apoptotic protein kinase regulated through the phosphatidylinositol 3-kinase (PI3-kinase) pathway by cellular stimuli, hormones and growth factors. The objective of the present study was to examine the role of SGK1 in the renoprotective effects of EPO in renal I/R injury. In vitro, cultures of HEK293 cells were exposed to 16h hypoxia. Incubation with EPO at a doses of 400U/ml exerted a protective effect on cell death assessed by LDH release and Annexin V FACS analysis. This was paralleled by up-regulation of SGK1 expression, as well as phosphorylation. Downregulation of SGK1 expression by small interfering RNA technique ameliorated the anti-apoptotic effect of EPO treatment. In an in vivo rat model of unilateral renal I/R injury, rats were treated with 500U/kg EPO 24h prior to ischemia. EPO resulted in less severe tissue injury and ameliorated the elevation in creatinine and urea nitrogen levels 24h after reperfusion. Furthermore, SGK1 expression and phosphorylation were higher in EPO compared to vehicle-treated rats as demonstrated by real-time PCR, Western blot and immunofluorescence technique. We conclude that EPO protects from renal I/R injury and SGK1 might contribute to the mediation of EPO effects under ischemic conditions.

Increased Heat Shock Protein 72 Expression in Celiac Disease

Background and Objectives: Heat shock protein (HSP) 72, a known chaperone, has potential epithelial barrier protecting, antiapoptotic, and immune system regulatory effects; therefore, our aim was to study its involvement in the pathology of celiac disease (CD). Patients and Methods: Duodenal biopsy specimens were collected from children with untreated and treated CD and from controls. mRNA expression, protein level, and localization of HSP72 were determined. Results: Elevated HSP72 mRNA expression and higher protein levels were found in the duodenal mucosa of children with untreated CD as well as in children with treated CD compared with those in controls. In the duodenal mucosa of children with treated CD, HSP72 mRNA expression was decreased and HSP72 protein levels were lower than those in children with untreated CD. We detected intensive HSP72 staining in the villous enterocytes and immune cells of the lamina propria in the duodenal villi of children with untreated CD compared with that in controls. Conclusions: The increased expression and altered localization of HSP72 in CD indicate that HSP72 should have a role in protection against gliadin-induced cytotoxicity. HSP72 may exert antiapoptotic effect and contribute to preservation of intestinal epithelial barrier integrity. Moreover, HSP72 as a ligand of TLR2 and TLR4 may promote innate immune responses and warn the cells of the potential injury.