Immunomodulatory role of Parkinson's disease 7 in inflammatory bowel disease

Recently the role of Parkinson’s disease 7 (PARK7) was studied in gastrointestinal diseases, however, the complex role of PARK7 in the intestinal inflammation is still not completely clear. Expression and localization of PARK7 were determined in the colon biopsies of children with inflammatory bowel disease (IBD), in the colon of dextran sodium sulphate (DSS) treated mice and in HT-29 colonic epithelial cells treated with interleukin (IL)-17, hydrogen peroxide (H₂O₂), tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β or lipopolysaccharide (LPS). Effect of PARK7 on the synthesis of IBD related cytokines was determined using PARK7 gene silenced HT-29 cells and 3,4,5-trimethoxy-N-(4-(8-methylimidazo(1,2-a)pyridine-2-yl)phenyl)benzamide (Comp23)—compound increasing PARK7 activity—treated mice with DSS-colitis. PARK7 expression was higher in the mucosa of children with Crohn’s disease compared to that of controls. While H₂O₂ and IL-17 treatment increased, LPS, TNF-α or TGF-β treatment decreased the PARK7 synthesis of HT-29 cells. PARK7 gene silencing influenced the synthesis of IL1B, IL6, TNFA and TGFB1 in vitro. Comp23 treatment attenuated the ex vivo permeability of colonic sacs, the clinical symptoms, and mucosal expression of Tgfb1, Il1b, Il6 and Il10 of DSS-treated mice. Our study revealed the role of PARK7 in the regulation of IBD-related inflammation in vitro and in vivo, suggesting its importance as a future therapeutic target.

Interleukin-24 regulates mucosal remodeling in inflammatory bowel diseases

Background

Recently, increased interleukin (IL)-24 expression has been demonstrated in the colon biopsies of adult patients with inflammatory bowel disease (IBD). However, the role of IL-24 in the pathomechanism of IBD is still largely unknown.

Methods

Presence of IL-24 was determined in the samples of children with IBD and in the colon of dextran sodium sulfate (DSS) treated mice. Effect of inflammatory factors on IL24 expression was determined in peripheral blood (PBMCs) and lamina propria mononuclear cells (LPMCs). Also, the impact of IL-24 was investigated on HT-29 epithelial cells and CCD-18Co colon fibroblasts. Expression of tissue remodeling related genes was investigated in the colon of wild type (WT) mice locally treated with IL-24 and in the colon of DSS treated WT and Il20rb knock out (KO) mice.

Results

 Increased amount of IL-24 was demonstrated in the serum and colon samples of children with IBD and DSS treated mice compared to that of controls. IL-1β, LPS or H₂O₂ treatment increased the expression of IL24 in PBMCs and LPMCs. IL-24 treatment resulted in increased amount of TGF-β and PDGF-B in HT-29 cells and enhanced the expression of extracellular matrix (ECM)-related genes and the motility of CCD-18Co cells. Similarly, local IL-24 treatment increased the colonic Tgfb1 and Pdgfb expression of WT mice. Moreover, expression of pro-fibrotic Tgfb1 and Pdgfb were lower in the colon of DSS treated Il20rb KO compared to that of WT mice. The disease activity index of colitis was less severe in DSS treated Il20rb KO compared to WT mice.

Conclusion

Our study suggest that IL-24 may play a significant role in the mucosal remodeling of patients with IBD by promoting pro-fibrotic processes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02890-7.

Role of microRNA-223 in the regulation of poly(ADP-ribose) polymerase in pediatric patients with Crohn's disease

OBJECTIVES

Crohn's disease (CD) is a multifactorial disease, characterized by oxidant-induced tissue injury with a possible activation of poly(ADP-ribose) polymerase (PARP)-1. MicroRNAs (miRs) can offer a potential link between the genetic susceptibility, environmental and immunologic factors in the pathogenesis of CD. Previously, PARP-1 was identified as a direct target gene of miR-223 in an epithelial cell line. Our aim was to examine PARP activation and miR-223 expression in colonic biopsies of pediatric CD. To support our in vivo findings, the effect of lipopolysaccharide (LPS) on same parameters was examined in HT-29 colonic epithelial cell line.

METHODS

Colonic biopsies were taken from patients with macroscopically inflamed and intact mucosa with CD and controls. LPS treated HT-29 cells served as our in vitro model. To analyze the PARP-1 expression real-time PCR, Western blot and immunohistochemical analyses were used. PARP-1 enzymatic activity was assessed on the basis of poly(ADP-ribosyl)ated proteins. Expression of miR-223 was examined by real-time PCR.

RESULTS

PARP-1 mRNA and miR-223 expression was significantly elevated, however, the amount of PARP-1 protein and poly(ADP-ribose) was reduced in pediatric CD compared to controls. LPS incubation did not affect the expression of PARP-1 mRNA, however, decreased miR-223 expression, and enhanced PARP-1 activity.

CONCLUSIONS

In our study, we showed that the expression of miR-223 is up-regulated and poly(ADP-ribosyl)ation is reduced in pediatric patients with CD. Moreover, we confirmed their opposite change in LPS treated epithelial cells, too. These data suggest that the hypofunctionality of PARP-1 may play a potential role in the pathomechanism of CD.

Selective measurement of α smooth muscle actin: why β-actin can not be used as a housekeeping gene when tissue fibrosis occurs

Background

Prevalence of fibroproliferative diseases, including chronic kidney disease is rapidly increasing and has become a major public health problem worldwide. Fibroproliferative diseases are characterized by increased expression of α smooth muscle actin (α-SMA) that belongs to the family of the six conserved actin isoforms showing high degree homology. The aim of the present study was to develop real-time PCRs that clearly discriminate α-SMA and ß-actin from other actin isoforms.

Results

Real-time PCRs using self-designed mouse, human and rat specific α-SMA or ß-actin primer pairs resulted in the specific amplification of the artificial DNA templates corresponding to mouse, human or rat α-SMA or ß-actin, however ß-actin showed cross-reaction with the housekeeping γ-cyto-actin. We have shown that the use of improperly designed literary primer pairs significantly affects the results of PCRs measuring mRNA expression of α-SMA or ß-actin in the kidney of mice underwent UUO.

Conclusion

We developed a set of carefully designed primer pairs and PCR conditions to selectively determine the expression of mouse, human or rat α-SMA and ß-actin isoforms. We demonstrated the importance of primer specificity in experiments where the results are normalized to the expression of ß-actin especially when fibrosis and thus increased expression of α-SMA is occur.

Altered mucosal expression of microRNAs in pediatric patients with inflammatory bowel disease

INTRODUCTION

MicroRNAs (miRs) came recently into focus as promising novel research targets offering new insights into the pathogenesis of inflammatory bowel diseases (IBD).

AIMS

The aim of our study was to identify a pediatric IBD (pIBD) characteristic miR profile serving as potential Crohn's disease (CD) and ulcerative colitis (UC) specific diagnostic pattern and to further analyze the related target genes.

METHODS

Small RNA sequencing was performed on inflamed and intact colonic biopsies of CD, and control patients. Selected miRs were further investigated by RT-PCR, complemented with an UC group, in order to address the differential diagnostic potential of miRs in the two IBD subtypes. To analyze network connection of differentially expressed miRs and their target genes MiRTarBase database and previous transcriptome sequencing data from pediatric patient groups were used.

RESULTS

Sequencing analysis identified 170 miRs with altered expression. RT-PCR analysis revealed altered expression of miR-31, -125a, -142-3p, and -146a discriminating between the inflamed mucosa of CD and UC. In the intact mucosa of CD patients the expression of miR-18a, -20a, -21, -31, -99a, -99b, -100, -125a, -126, -142-5p, -146a, -185, -204, -221, and -223 was elevated compared to the controls. The expression of miR-20a, -204 and -221 was elevated exclusively in the intact region of CD patients compared to the controls. Enrichment analysis identified main IBD-related functional groups.

CONCLUSIONS

We demonstrated a characteristic colonic miR pattern in pIBD that could facilitate deeper understanding of the pathomechanism of IBD and may serve as a diagnostic tool.

Microarray Analysis Reveals Increased Expression of Matrix Metalloproteases and Cytokines of Interleukin-20 Subfamily in the Kidneys of Neonate Rats Underwent Unilateral Ureteral Obstruction: A Potential Role of IL-24 in the Regulation of Inflammation and Tissue Remodeling

BACKGROUND/AIMS

Congenital obstructive nephropathy (CON) is the main cause of pediatric chronic kidney diseases leading to renal fibrosis. High morbidity and limited treatment opportunities of CON urge the better understanding of the underlying molecular mechanisms.

METHODS

To identify the differentially expressed genes, microarray analysis was performed on the kidney samples of neonatal rats underwent unilateral ureteral obstruction (UUO). Microarray results were then validated by real-time RT-PCR and bioinformatics analysis was carried out to identify the relevant genes, functional groups and pathways involved in the pathomechanism of CON. Renal expression of matrix metalloproteinase (MMP)-12 and interleukin (IL)-24 were evaluated by real-time RT-PCR, flow cytometry and immunohistochemical analysis. Effect of the main profibrotic factors on the expression of MMP-12 and IL-24 was investigated on HK-2 and HEK-293 cell lines. Finally, the effect of IL-24 treatment on the expression of pro-inflammatory cytokines and MMPs were tested in vitro.

RESULTS

Microarray analysis revealed 880 transcripts showing >2.0-fold change following UUO, enriched mainly in immune response related processes. The most up-regulated genes were MMPs and members of IL-20 cytokine subfamily, including MMP-3, MMP-7, MMP-12, IL-19 and IL-24. We found that while TGF-β treatment inhibits the expression of MMP-12 and IL-24, H2O2 or PDGF-B treatment induce the epithelial expression of MMP-12. We demonstrated that IL-24 treatment decreases the expression of IL-6 and MMP-3 in the renal epithelial cells.

CONCLUSIONS

This study provides an extensive view of UUO induced changes in the gene expression profile of the developing kidney and describes novel molecules, which may play significant role in the pathomechanism of CON.

Sex differences in renin response and changes of capillary diameters after renal ischemia/reperfusion injury

Activation of the RAS has a crucial role in the progression of ischemia/reperfusion-associated CAD. The regulation of RAS differs in the two genders. However, the extent of gender differences and locations of renin production have not been revealed yet. We investigated in vivo the local renin production in the two genders during ischemia/reperfusion injury. In male and female Wistar rats, renal ischemia was induced followed by a reperfusion period of two, eight, 16, 24, or 48 h. We applied flow cytometry to measure renin content and multiphoton imaging to visualize renin granules and changes of peritubular diameters in vivo during ischemia/reperfusion. Renin content decreased in CD in the first eight h of reperfusion; however, after 16 h, its amount increased. In males, the production of renin was more pronounced, and the duration of vasoconstriction was longer with a subsequent phase of vessel hyperdilation compared to females. Renal ischemia/reperfusion injury induces renin response not only in the JGA, but also in the CD segment. Renin production is more explicit in males than in females which, via increased angiotensin II production, might explain the different dynamism of renal vessel regulation between the two genders.

Increased duodenal expression of miR-146a and -155 in pediatric Crohn’s disease

AIM: To evaluate the role of microRNA (miR)-146a, -155 and -122 in the duodenal mucosa of pediatric patients with Crohn’s disease (CD) and the effect of transforming growth factor-β (TGF-β) on these miRs in duodenal epithelial and fibroblast cells.

METHODS: Formalin-fixed, paraffin-embedded biopsies derived from the macroscopically inflamed (CD inflamed: n = 10) and intact (CD intact: n = 10) duodenal mucosa of pediatric CD patients and control children (C: n = 10) were examined. Expression of miR-146a, -155 and -122 was determined by real-time polymerase-chain reaction (PCR). The expression of the above miRs was investigated in recombinant human TGF-β (1 nmol/L, 24 h) or vehicle treated small intestinal epithelial cells (CCL-241) and primary duodenal fibroblast cells derived from healthy children as well.

RESULTS: Expression of miR-146a was significantly higher in the inflamed duodenal mucosa compared to the intact duodenal mucosa of children with CD (CD inflamed: 3.21 ± 0.50 vs CD intact: 0.62 ± 0.26, P≤ 0.01) and to the control group (CD inflamed: 3.21 ± 0.50 vs C: 1.00 ± 0.33, P≤ 0.05). The expression of miR-155 was significantly increased in the inflamed region of the duodenum compared to the control group (CD inflamed: 4.87 ± 1.02 vs Control: 1.00 ± 0.40, P≤ 0.001). The expression of miR-122 was unchanged in the inflamed or intact mucosa of CD patients compared to controls. TGF-β treatment significantly decreased the expression of miR-155 in small intestinal epithelial cells (TGF-β: 0.7 ± 0.083 vs Control: 1 ± 0.09, P≤ 0.05) and also the expression of miR-146a (TGF-β: 0.67 ± 0.04 vs Control: 1 ± 0.15, P≤ 0.01) and miR-155 (TGF-β: 0.72 ± 0.09 vs Control: 1 ± 0.06, P≤ 0.05) in primary duodenal fibroblasts compared to corresponding vehicle treated controls. TGF-β treatment did not influence the expression of miR-122.

CONCLUSION: The elevated expression of miR-146a and -155 in the inflamed duodenal mucosa of CD patients suggests the role of these miRs in the pathomechanism of inflammatory bowel disease. Anti-inflammatory TGF-β plays an important role in the regulation of the expression of these miRs.

Role of Altered Expression of miR-146a, miR-155, and miR-122 in Pediatric Patients with Inflammatory Bowel Disease

BACKGROUND

Evidence suggests the central role of tumor necrosis factor (TNF)-α in the pathomechanism of inflammatory bowel disease (IBD); however, its effect on epigenetic factors, including small non-coding microRNAs (miRs), is less known. Our present aim was the comparative investigation of the expression of TNF-α and immune response-related miRs in children with Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

Fresh-frozen (FF) and formalin-fixed, paraffin-embedded (FFPE) biopsies were used to analyze the expression of miR-146a, -155, -122, and TNF-α by real-time reverse transcription polymerase chain reaction in macroscopically inflamed (CD: 12 FFPE and 24 FF; UC: 10 FF) and intact (CD: 12 FFPE; 14 FF) colonic biopsies of children with IBD and controls (16 FFPE; 23 FF). The expression of miR-146a, -155, and -122 was also determined in TNF-α-treated HT-29 colonic epithelial cells.

RESULTS

Increased expression of TNF-α was observed in the colonic mucosa of children with CD and UC in comparison with controls. Expression of miR-146a and -155 was higher in the inflamed mucosa of children with CD and UC than in the intact mucosa. Expression of miR-122 elevated in the macroscopically intact colonic regions of CD compared with controls and patients with UC. In HT-29 cells, TNF-α treatment increased the expression of miR-146a and -155, but not that of miR-122.

CONCLUSIONS

Our results showed altered expression of miR-146a, -155, and -122 in the colonic mucosa of children with IBD and in TNF-α-treated colonic epithelial cells. Our data suggest the TNF-α-related involvement of these miRs in the pathogenesis of IBD.

Peroxisome proliferator-activated receptor-γ and thymic stromal lymphopoietin are involved in the pathophysiology of childhood coeliac disease

Celiac disease (CD) is a chronic autoimmune enteropathy caused by exposure to dietary gluten in genetically predisposed individuals. The transcription factor peroxisome proliferator-activated receptor gamma (PPARγ) was shown to exert protective effects in several immune-mediated disorders. Activation of PPARγ suppressed the expression of thymic stromal lymphopoietin (TSLP), an inducer of proinflammatory cytokines. Since the role of TSLP in gluten-sensitive enteropathy is completely unknown, we investigated the involvement of TSLP and its regulator PPARγ in childhood CD. We collected duodenal biopsy specimens from 19 children with newly diagnosed CD, 6 children with treated CD (gluten-free diet, GFD), and 10 controls. Expression of mRNA and protein levels of PPARγ, TSLP, and TSLP receptor were determined by real-time RT-PCR and Western blot, respectively. Duodenal localization of PPARγ and TSLP was studied by immunohistochemistry. In duodenal mucosa of children with CD, the amount of PPARγ was significantly lower and simultaneously that of TSLP significantly higher compared to controls (p < 0.05). In GFD-treated patients, the levels of PPARγ mRNA and protein were significantly higher while that of TSLP markedly lower compared to newly diagnosed CD (p < 0.05). Immunohistochemistry revealed PPARγ and TSLP expression in lamina propria immune cells and in enterocytes. Low expression of PPARγ and high expression of TSLP in the duodenal mucosa of children with newly diagnosed CD suggest that they are involved in the pathophysiology of CD. We hypothesize that PPARγ may be an inhibitory regulator of TSLP-stimulated inflammatory processes in CD.

Involvement of heat shock proteins in gluten-sensitive enteropathy

Gluten-sensitive enteropathy, also known as coeliac disease (CD), is an autoimmune disorder occurring in genetically susceptible individuals that damages the small intestine and interferes with the absorption of other nutrients. As it is triggered by dietary gluten and related prolamins present in wheat, rye and barley, the accepted treatment for CD is a strict gluten-free diet. However, a complete exclusion of gluten-containing cereals from the diet is often difficult, and new therapeutic strategies are urgently needed. A class of proteins that have already emerged as drug targets for other autoimmune diseases are the heat shock proteins (HSPs), which are highly conserved stress-induced chaperones that protect cells against harmful extracellular factors. HSPs are expressed in several tissues, including the gastrointestinal tract, and their levels are significantly increased under stress circumstances. HSPs exert immunomodulatory effects, and also play a crucial role in the maintenance of epithelial cell structure and function, as they are responsible for adequate protein folding, influence the degradation of proteins and cell repair processes after damage, and modulate cell signalling, cell proliferation and apoptosis. The present review discusses the involvement of HSPs in the pathophysiology of CD. Furthermore, HSPs may represent a useful therapeutic target for the treatment of CD due to the cytoprotective, immunomodulatory, and anti-apoptotic effects in the intestinal mucosal barrier.

Expression of PARK7 is increased in celiac disease

Recently, it has been suggested that the gene called Parkinson's disease 7 (PARK7) might be an upstream activator of hypoxia-inducible factor (HIF)-1α, which plays a major role in sustaining intestinal barrier integrity. Furthermore, PARK7 has been proposed to participate in the Toll-like receptor (TLR)-dependent regulation of the innate immune system. Our aim was to investigate the involvement of PARK7 in the pathogenesis of coeliac disease (CD). Duodenal biopsy specimens were collected from 19 children with untreated CD, five children with treated CD (maintained on gluten-free diet), and ten children with histologically normal duodenal biopsies. PARK7 mRNA expression and protein level were determined by real-time polymerase chain reaction (PCR) and Western blot, respectively. Localization of PARK7 was visualized by immunofluorescence staining. Protein level of PARK7 increased in the duodenal mucosa of children with untreated CD compared to children with treated CD or to control biopsies (p <0.03). We detected intensive PARK7 staining in the epithelial cells and lamina propria of the duodenal mucosa of children with untreated CD compared with that in control biopsies. Our finding that mucosal expression of PARK7 is increased suggests that PARK7 is involved in the pathogenesis of gastrointestinal diseases, notably CD. Our results suggest that PARK7 may alter processes mediated by HIF-1α and TLR4, which supports a role for PARK7 in the maintenance of epithelial barrier integrity, immune homeostasis, or apoptosis.

The role of intestinal alkaline phosphatase in pediatric inflammatory bowel and celiac diseases

Intestinal alkaline phosphatase enzyme plays a pivotal role in the maintenance of intestinal mucosal barrier integrity with the detoxification capacity of lipopolysaccharide, the ligand of Toll-like receptor 4. The inappropriate immune responses and the damage of the mucosal barrier may contribute to the initiation of inflammatory bowel and celiac diseases. In the inflamed colonic mucosa of children with inflammatory bowel disease and in the duodenal mucosa of newly diagnosed children with celiac disease, the decreased intestinal alkaline phosphatase and increased Toll-like receptor 4 protein expression may generate enhanced lipopolysaccharide activity, which may strengthen tissue damaging processes. The enhancement of intestinal alkaline phosphatase activity in an animal model of colitis and in therapy resistant, adult patients with ulcerative colitis reduced the symptoms of intestinal inflammation. In accordance with these results, the targeted intestinal administration of the enzyme in the two examined disorders may be a supplemental therapeutic option in the future. Orv. Hetil., 2012, 153, 1389–1395.

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 Crohn’s 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.

Increased synthesis of vascular endothelial growth factor in allergic airway inflammation in histidine decarboxylase knockout (HDC(-/-)) mice

Histamine and vascular endothelial growth factor (VEGF) have been implicated in the pathogenesis of allergic asthma; they enhance inflammation, vascular permeability, and mucus secretion. Histamine was suggested to alter the level of VEGF via the H2 receptors. Here the authors have applied histidine decarboxylase gene-targeted (HDC(-/-)) mice, lacking histamine, to investigate the effect of histamine deficiency on VEGF expression in an animal model of asthma. HDC(-/-) and wild-type (WT) mice were sensitized and challenged with ovalbumin (OVA). VEGF mRNA expression and protein level were determined in the lung. Number of VEGF-positive immune cells of bronchoalveolar lavage (BAL) and their intracellular VEGF content were measured by flow cytometry. VEGF protein level in the lung and in the BAL cells was increased in OVA treated (HDC(-/-)(ova) as well as in WT(ova)) animals compared to their controls. However, there was no difference in the VEGF levels between HDC(-/-) or WT animals, either in the lung or in the BAL cells. In conclusion, increased VEGF production of the lung or BAL immune cells can be induced by allergen provocation independently from the genetic background of the animals. These data suggest that VEGF-mediated allergic processes can persist in the absence of histamine.

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 Th17 cells in rheumatoid arthritis]

Th17 cells are the newly described subset of the CD4(+) T lymphocytes. Activated Th17 cells are characterized by their ability to produce IL-17A and other pro-inflammatory cytokines. IL-17A regulates immune function through its cell-surface receptor expressed on epithelial-and endothelial cells, fibroblasts and leukocytes by promoting neutrophil recruitment and releasing further pro-inflammatory mediators. Failures of the susceptible balance of the immunoregulation may lead to unchecked immune response and autoimmune diseases. The central role of Th17 cells and cytokines produced by Th17 cells were confirmed in a wide variety of human autoimmune diseases, including rheumatoid arthritis. Recently Th17 cells and its cytokines come into the focus of immunological research as potential therapeutic targets.

Estrogen augments the T cell-dependent but not the T-independent immune response

Estrogen plays a critical regulatory role in the development and maintenance of immunity. Its role in the regulation of antibody synthesis in vivo is still not completely clear. Here, we have compared the effect of estrogen on T cell-dependent (TD) and T cell-independent type 2 (TI-2) antibody responses. The results provide the first evidence that estrogen enhances the TD but not the TI-2 response. Ovariectomy significantly decreased, while estrogen re-administration increased the number of hapten-specific IgM- and IgG-producing cells in response to TD antigen. In vitro experiments also show that estrogen may have a direct impact on B and T cells by inducing rapid signaling events, such as Erk and AKT phosphorylation, cell-specific Ca(2+) signal, and NFkappaB activation. These non-transcriptional effects are mediated by classical estrogen receptors and partly by an as yet unidentified plasma membrane estrogen receptor. Such receptor- mediated rapid signals may modulate the in vivo T cell-dependent immune response.

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

BACKGROUND

Galectin-9 (Gal-9) is a member of the growing family of beta-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 (G(OVA)). Another group of animals was allergized with OVA and also treated with dexamethasone (DEX) (G(OVA+DEX)). The control group (G(PBS)) 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 G(OVA )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 G(OVA) compared to G(PBS) or G(OVA+DEX )mice. Moreover, Gal-9 protein level was elevated in the lungs of G(OVA) 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.

Dehydroepiandrosterone pretreatment alters the ischaemia/reperfusion-induced VEGF, IL-1 and IL-6 gene expression in acute renal failure

BACKGROUND

Beneficial effects of dehydroepiandrosterone (DHEA) pretreatment were reported in ischaemia/reperfusion (I/R)-induced kidney damage.

METHODS

To investigate the mechanism of DHEA pretreatment during renal I/R injury, the left renal pedicles of DHEA- [G(DHEA); 4.0 mg/kg/day DHEA dissolved in propylene glycol (PG)] and PG-pretreated male Wistar rats (G(PG)) were clamped for 55 min followed by 2 (T(2)) and 24 h (T(24)) of reperfusion. Sham-operated, non-clamped animals (T(0)) served as controls in both groups. Renal function, kidney morphology and interleukin 1beta (IL-1beta), interleukin 6 (IL-6) and vascular endothelial growth factor (VEGF) expression were determined in the kidneys of both groups.

RESULTS

Renal functional parameters and kidney structure did not differ in G(DHEA) versus G(PG) at any time point. Renal mRNA expression of IL-1beta was lower at T(0), while IL-6 at T(2) was lower in G(DHEA) than in G(PG).While renal VEGF mRNA expression remained unchanged, protein levels were increased at T(2) and T(24 )compared to T(0) kidneys in both groups. VEGF protein levels were lower at T(2) and T(24 )in G(DHEA) than in G(PG).

CONCLUSION

We found that DHEA pretreatment alters renal IL-1beta, IL-6 and VEGF synthesis. Moreover, contrary changes in VEGF mRNA and protein levels suggest that VEGF synthesis - distinct from other organs - might be primarily posttranscriptionally regulated in postischaemic rat kidneys.