Extracellular Vesicles of Patients on Peritoneal Dialysis Inhibit the TGF-β- and PDGF-B-Mediated Fibrotic Processes

Among patients on peritoneal dialysis (PD), 50-80% will develop peritoneal fibrosis, and 0.5-4.4% will develop life-threatening encapsulating peritoneal sclerosis (EPS). Here, we investigated the role of extracellular vesicles (EVs) on the TGF-β- and PDGF-B-driven processes of peritoneal fibrosis. EVs were isolated from the peritoneal dialysis effluent (PDE) of children receiving continuous ambulatory PD. The impact of PDE-EVs on the epithelial-mesenchymal transition (EMT) and collagen production of the peritoneal mesothelial cells and fibroblasts were investigated in vitro and in vivo in the chlorhexidine digluconate (CG)-induced mice model of peritoneal fibrosis. PDE-EVs showed spherical morphology in the 100 nm size range, and their spectral features, CD63, and annexin positivity were characteristic of EVs. PDE-EVs penetrated into the peritoneal mesothelial cells and fibroblasts and reduced their PDE- or PDGF-B-induced proliferation. Furthermore, PDE-EVs inhibited the PDE- or TGF-β-induced EMT and collagen production of the investigated cell types. PDE-EVs contributed to the mesothelial layer integrity and decreased the submesothelial thickening of CG-treated mice. We demonstrated that PDE-EVs significantly inhibit the PDGF-B- or TGF-β-induced fibrotic processes in vitro and in vivo, suggesting that EVs may contribute to new therapeutic strategies to treat peritoneal fibrosis and other fibroproliferative diseases.

Optimization of Sirius Red-Based Microplate Assay to Investigate Collagen Production In Vitro

Tissue fibrosis is characterized by chronic fibroblast activation and consequently excessive accumulation of collagen-rich extracellular matrix. In vitro microplate-based assays are essential to investigate the underlying mechanism and the effect of antifibrotic drugs. In this study, in the absence of a gold-standard method, we optimized a simple, cost-effective, Sirius Red-based colorimetric measurement to determine the collagen production of fibroblasts grown on 96-well tissue culture plates. Based on our findings, the use of a serum-free medium is recommended to avoid aspecific signals, while ascorbate supplementation increases the collagen production of fibroblasts. The cell-associated collagens can be quantified by Sirius Red staining in acidic conditions followed by alkaline elution. Immature collagens can be precipitated from the culture medium by acidic Sirius Red solution, and after subsequent centrifugation and washing steps, their amount can be also measured. Increased attention has been paid to optimizing the assay procedure, including incubation time, temperature, and solution concentrations. The resulting assay shows high linearity and sensitivity and could serve as a useful tool in fibrosis-related basic research as well as in preclinical drug screening.

High Salt Promotes Inflammatory and Fibrotic Response in Peritoneal Cells

Recent studies draw attention to how excessive salt (NaCl) intake induces fibrotic alterations in the peritoneum through sodium accumulation and osmotic events. The aim of our study was to better understand the underlying mechanisms. The effects of additional NaCl were investigated on human primary mesothelial cells (HPMC), human primary peritoneal fibroblasts (HPF), endothelial cells (HUVEC), immune cells (PBMC), as well as ex vivo on peritoneal tissue samples. Our results showed that a high-salt environment and the consequently increased osmolarity increase the production of inflammatory cytokines, profibrotic growth factors, and components of the renin-angiotensin-aldosterone system, including IL1B, IL6, MCP1, TGFB1, PDGFB, CTGF, Renin and Ace both in vitro and ex vivo. We also demonstrated that high salt induces mesenchymal transition by decreasing the expression of epithelial marker CDH1 and increasing the expression of mesenchymal marker ACTA2 and SNAIL1 in HPMCs, HUVECs and peritoneal samples. Furthermore, high salt increased extracellular matrix production in HPFs. We demonstrated that excess Na+ and the consequently increased osmolarity induce a comprehensive profibrotic response in the peritoneal cells, thereby facilitating the development of peritoneal fibrosis.

Zonulin as a Potential Therapeutic Target in Microbiota-Gut-Brain Axis Disorders: Encouraging Results and Emerging Questions

The relationship between dysbiosis and central nervous diseases has been proved in the last 10 years. Microbial alterations cause increased intestinal permeability, and the penetration of bacterial fragment and toxins induces local and systemic inflammatory processes, affecting distant organs, including the brain. Therefore, the integrity of the intestinal epithelial barrier plays a central role in the microbiota-gut-brain axis. In this review, we discuss recent findings on zonulin, an important tight junction regulator of intestinal epithelial cells, which is assumed to play a key role in maintaining of the blood-brain barrier function. In addition to focusing on the effect of microbiome on intestinal zonulin release, we also summarize potential pharmaceutical approaches to modulate zonulin-associated pathways with larazotide acetate and other zonulin receptor agonists or antagonists. The present review also addresses the emerging issues, including the use of misleading nomenclature or the unsolved questions about the exact protein sequence of zonulin.

PARK7/DJ-1 as a Therapeutic Target in Gut-Brain Axis Diseases

It is increasingly known that Parkinson's (PD) and Alzheimer's (AD) diseases occur more frequently in patients with inflammatory gastrointestinal diseases including inflammatory bowel (IBD) or celiac disease, indicating a pathological link between them. Although epidemiological observations suggest the existence of the gut-brain axis (GBA) involving systemic inflammatory and neural pathways, little is known about the exact molecular mechanisms. Parkinson's disease 7 (PARK7/DJ-1) is a multifunctional protein whose protective role has been widely demonstrated in neurodegenerative diseases, including PD, AD, or ischemic stroke. Recent studies also revealed the importance of PARK7/DJ-1 in the maintenance of the gut microbiome and also in the regulation of intestinal inflammation. All these findings suggest that PARK7/DJ-1 may be a link and also a potential therapeutic target in gut and brain diseases. In this review, therefore, we discuss our current knowledge about PARK7/DJ-1 in the context of GBA diseases.

MO714: PARK7—A Novel Therapeutic Target for Peritoneal Dialysis Induced Peritoneal Membrane and Vascular Transformation

BACKGROUND AND AIMS

Patients with chronic kidney disease (CKD) suffer from increased oxidative stress, which is further aggravated in patients on peritoneal dialysis (PD). Parkinson disease protein 7 (PARK7) has antioxidant and antiapoptotic activity; its role in PD is unknown.

METHOD

Transcriptome and proteome data sets from microdissected omental arterioles obtained from age-matched non-CKD children, children with CKD5 and children on PD with fluids containing low or high concentrations of glucose degradation products (GDP; n = 6/group) underwent PARK7 related gene set analysis (FDR < 0.05). Respective parietal peritoneal tissues (n = 60) underwent digital histomorphometry analyses. PARK7 western blotting was performed in effluents of eight children on high-GDP PD. Human umbilical endothelial cells (HUVEC) viability (MTT assay) and transepithelial electrical resistance (TER, Transwells) and 4-, 10- and 70-kDa dextran transport were measured (n = 6–12/group). As an extreme phenotype approach of PD toxicity, C57/BL6J mice were treated with chlorhexidine digluconate (CG) and PARK7 activator for 7 days and parietal peritoneal damage was quantitated (n = 6–8/group).

RESULTS

Arteriolar transcriptome analyses in children on low-GDP PD demonstrated the enrichment of PARK7 related GO terms of oxidant detoxification as compared to CKD5 and in children on high-GDP PD that of reactive oxygen species-, mitochondria- and apoptosis-related processes. On the proteome level the DNA repair/organization, catabolic and mitochondria associated processes were enriched in children on low-GDP PD, and mitochondrial processes in children on high-GDP PD.

PARK7 was detected in the parietal peritoneal tissues in mesothelial, endothelial and inflammatory cells, in myocytes and fibroblasts and was present in the PD effluents. Total peritoneal and submesothelial PARK7 abundance was similar in controls, patients with CKD5 and in patients on low-GDP PD, but 2-fold increased in patients on high GDP PD compared to controls and CKD5. Mesothelial PARK7 was 2-fold increased in children on low-GDP PD versus CKD5, endothelial PARK7 abundance was similar in all four groups.

In low-GDP PD patients endothelial PARK7 abundance correlated with vessel lumen/vessel diameter ratio (r = 0.53, P = 0.06), i.e. inversely with lumen obliteration. Submesothelial PARK7 correlated with microvessel density (r = 0.55, P = 0.05), with submesothelial hypoxia inducible factor-1 and angiopoietin-1 and -2 (ρ = 0.63, P = 0.023; r = 0.91, P < 0.0001; r = 0.60, P = 0.03) but not with VEGF. Submesothelial and endothelial PARK7 correlated with respective caspase 3 abundances (r = 0.74/0.68, P = 0.009/0.015).

In HUVEC methylglyoxal (MG) dose- and time-dependently reduced viability, coincubation with PARK7 activator partially preserved endothelial cell viability. In Transwells, MG treatment decreased TER and increased dextran transport, but none of them was improved by PARK7 activation.

In mice treated with CG submesothelial thickness was 2-fold increased, microvessel density was unchanged; PARK7 protein abundance was 5-fold reduced. Co-treatment of CG with PARK7 activator prevented the submesothelial thickening.

CONCLUSION

PD modifies arteriolar PARK7 related biological processes of oxidant detoxification, mitochondria- and apoptosis-related processes. PARK7 is ubiquitously expressed in the parietal peritoneum and regulated by the GDP content of PD fluids. In patients on low-GDP PD, PARK7 abundance correlated with the degree of arteriolar lumen narrowing, and VEGF-independent angiogenesis. Activation of PARK7 preserves endothelial cell viability in vitro and prevents CG induced peritoneal membrane damage in mice and thus represents a potential novel therapeutic approach.

Transient Agarose Spot (TAS) Assay: A New Method to Investigate Cell Migration

Fibroblasts play a central role in diseases associated with excessive deposition of extracellular matrix (ECM), including idiopathic pulmonary fibrosis. Investigation of different properties of fibroblasts, such as migration, proliferation, and collagen-rich ECM production is unavoidable both in basic research and in the development of antifibrotic drugs. In the present study we developed a cost-effective, 96-well plate-based method to examine the migration of fibroblasts, as an alternative approach to the gold standard scratch assay, which has numerous limitations. This article presents a detailed description of our transient agarose spot (TAS) assay, with instructions for its routine application. Advantages of combined use of different functional assays for fibroblast activation in drug development are also discussed by examining the effect of nintedanib—an FDA approved drug against IPF—on lung fibroblasts.

High salt diet impairs dermal tissue remodeling in a mouse model of IMQ induced dermatitis

Recent animal studies, as well as quantitative sodium MRI observations on humans demonstrated that remarkable amounts of sodium can be stored in the skin. It is also known that excess sodium in the tissues leads to inflammation in various organs, but its role in dermal pathophysiology has not been elucidated. Therefore, our aim was to study the effect of dietary salt loading on inflammatory process and related extracellular matrix (ECM) remodeling in the skin. To investigate the effect of high salt consumption on inflammation and ECM production in the skin mice were kept on normal (NSD) or high salt (HSD) diet and then dermatitis was induced with imiquimod (IMQ) treatment. The effect of high salt concentration on dermal fibroblasts (DF) and peripheral blood mononuclear cells (PBMC) was also investigated in vitro. The HSD resulted in increased sodium content in the skin of mice. Inflammatory cytokine Il17 expression was elevated in the skin of HSD mice. Expression of anti-inflammatory Il10 and Il13 decreased in the skin of HSD or HSD IMQ mice. The fibroblast marker Acta2 and ECM component Fn and Col1a1 decreased in HSD IMQ mice. Expression of ECM remodeling related Pdgfb and activation phosphorylated (p)-SMAD2/3 was lower in HSD IMQ mice. In PBMCs, production of IL10, IL13 and PDGFB was reduced due to high salt loading. In cultured DFs high salt concentration resulted in decreased cell motility and ECM production, as well. Our results demonstrate that high dietary salt intake is associated with increased dermal pro-inflammatory status. Interestingly, although inflammation induces the synthesis of ECM in most organs, the expression of ECM decreased in the inflamed skin of mice on high salt diet. Our data suggest that salt intake may alter the process of skin remodeling.

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.

Cyclooxygenase-2 Modulates Glycosaminoglycan Production in the Skin During Salt Overload

Sodium (Na⁺) can accumulate in the skin tissue, sequestered by negatively charged glycosaminoglycans (GAGs). During dietary salt overload, the amount and charge density of dermal GAG molecules - e.g., hyaluronic acid (HA) and chondroitin sulfate (CS) - increases; however, the regulation of the process is unknown. Previously, it has been demonstrated that the level of cyclooxygenase-2 (COX-2) activity and the content of prostaglandin E2 (PGE2) are elevated in the skin due to high-salt consumption. A link between the COX-2/PGE2 system and GAG synthesis was also suggested. We hypothesized that in dermal fibroblasts (DFs) high-sodium concentration activates the COX-2/PGE2 pathway and also that PGE2 increases the production of HA. Our further aim was to demonstrate that the elevation of the GAG content is ceased by COX-2 inhibition in a salt overloaded animal model. For this, we investigated the messenger RNA (mRNA) expression of COX-2 and HA synthase 2 enzymes as well as the PGE2 and HA production of DFs by real-time reverse transcription PCR (qRT-PCR) and ELISA, respectively. The results showed that both high-sodium concentration and PGE2 treatment increases HA content of the media. Sodium excess activates the COX-2/PGE2 pathway in DFs, and COX-2 inhibition decreases the synthesis of HA. In the animal experiment, the HA- and CS disaccharide content in the skin of male Wistar rats was measured using high performance liquid chromatography-mass spectrometry (HPLC-MS). In the skin of rats receiving high-salt diet, the content of both HA- and monosulfated-CS disaccharides increased, whereas COX-2 inhibition blocked this overproduction. In conclusion, high-salt environment could induce GAG production of DFs in a COX-2/PGE2-dependent manner. Moreover, the COX-2 inhibition resulted in a decreased skin GAG content of the salt overloaded rats. These data revealed a new DF-mediated regulation of GAG synthesis in the skin during salt overload.

The immunological background of glomerular injuries

The basic structural units of the renal filtration are the glomeruli, which, in addition to their passive hemodynamic function, also participate in complex immune-mediated mechanisms. The immune system as a double-edged sword maintains the physiological homeostasis of the glomeruli, but also plays a crucial role in the induction of glomerular damage. The immune-mediated chronic glomerular injures are the most common cause of end-stage renal diseases. The unregulated and overactive immune response can damage both the structural and the cellular components of the glomeruli, including the glomerular basal membrane, mesangial and capillary endothelial cells, podocytes, and parietal epithelium. The manuscript summarizes the role of the glomerular components and the natural and adaptive immune response in the pathomechanism of glomerular diseases. Orv Hetil. 2020; 161(24): 993-1001.

Characterization of IL-19, -20, and -24 in acute and chronic kidney diseases reveals a pro-fibrotic role of IL-24

BACKGROUND

Recently, the role of IL-19, IL-20 and IL-24 has been reported in renal disorders. However, still little is known about their biological role.

METHODS

Localization of IL-20RB was determined in human biopsies and in the kidneys of mice that underwent unilateral ureteral obstruction (UUO). Renal Il19, Il20 and Il24 expression was determined in ischemia/reperfusion, lipopolysaccharide, streptozotocin, or UUO induced animal models of kidney diseases. The effects of H₂O₂, LPS, TGF-β1, PDGF-B and IL-1β on IL19, IL20 and IL24 expression was determined in peripheral blood mononuclear cells (PBMCs). The extents of extracellular matrix (ECM) and α-SMA, Tgfb1, Pdgfb, and Ctgf expression were determined in the kidneys of Il20rb knockout (KO) and wild type (WT) mice following UUO. The effect of IL-24 was also examined on HK-2 tubular epithelial cells and NRK49F renal fibroblasts.

RESULTS

IL-20RB was present in the renal biopsies of patients with lupus nephritis, IgA and diabetic nephropathy. Amount of IL-20RB increased in the kidneys of mice underwent UUO. The expression of Il19, Il20 and Il24 increased in the animal models of various kidney diseases. IL-1β, H₂O₂ and LPS induced the IL19, IL20 and IL24 expression of PBMCs. The extent of ECM, α-SMA, fibronectin, Tgfb1, Pdgfb, and Ctgf expression was lower in the kidney of Il20rb KO compared to WT mice following UUO. IL-24 treatment induced the apoptosis and TGF-β1, PDGF-B, CTGF expression of HK-2 cells.

CONCLUSIONS

Our data confirmed the significance of IL-19, IL-20 and IL-24 in the pathomechanism of renal diseases. Furthermore, we were the first to demonstrate the pro-fibrotic effect of IL-24.

Role of IL-24 in the mucosal remodeling of children with coeliac disease

BACKGROUND

Recently, involvement of IL-19, IL-20 and IL-24 has been reported in inflammatory diseases associated with tissue remodeling. However, their impact on the pathomechanism of coeliac disease (CD) is still completely unknown.

METHODS

Expression of IL19, IL20 and IL24 was measured by real-time RT-PCR, protein amount of IL-24, α smooth muscle actin (α-SMA) and fibronectin (FN) was determined by Western-blot analysis in the duodenal biopsies of therapy naive children with CD and controls. Localization of IL-24 and IL-20RB was investigated by immunofluorescent staining in the duodenal mucosa. Effect of recombinant IL-1β, TNF-α, TGF-β and IL-17 treatment on the expression of IL19, IL20, IL24 and their receptors was investigated by real-time RT-PCR in small intestinal epithelial cells (FHs74Int), in primary duodenal myofibroblasts (pdMFs) and in peripheral blood mononuclear cells (PBMCs). Effect of IL-24 on H₂O₂ treated FHs74Int cells and on pdMFs was measured by MTT, LDH, Annexin V assays, real-time RT-PCR and by fluorescent microscopy.

RESULTS

We found increased level of IL-24 (3.3×, p < 0.05), α-SMA (2.4×, p < 0.05) and FN (2.3×, p < 0.05) in the duodenal mucosa and increased expression of IL19 (3.6×, p < 0.05) and IL24 (5.2×, p < 0.05) in the PBMCs of children with CD compared to that of controls. IL-1β was a strong inducer of IL24 expression of FHs74Int cells (9.9×, p < 0.05), pdMFs (552.9×, p < 0.05) or PBMCs (17.2×, p < 0.05), as well. IL-24 treatment reduced the number of apoptotic cells (0.5×, p < 0.05) and decreased the expression of inflammatory factors, including IL1A, IL6 and TNF of H₂O₂-treated FHs74Int cells. IL-24 decreased the proliferation (0.6×, p < 0.05) of PDGF-B treated pdMFs. Moreover, IL-24 treatment altered the morphology of pdMFs by influencing the size of the angles between stress fibers and the longitudinal axis of the cells (2.0×, p < 0.05) and the expression of cytoskeletal components, including ACTA2, ACTB, VIM, SNAI1 and SNAI2.

CONCLUSION

Our results suggest that IL-24 plays a significant role in the maintenance of duodenal mucosal integrity in CD.

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.

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.

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.

[Importance of diabetic nephropathy in childhood. Clinical findings and basic research in recent decades]

Over the past decades diabetes mellitus is becoming a global pandemic affecting more than 371 million people worldwide. Parallel with the increasing prevalence of type 1 diabetes, there is a growing number of type 2 diabetes cases among children and adolescents that poses new challenges to pediatricians. Diabetic nephropathy is one of the major causes of end stage renal disease, developing in approximately 30% of diabetic patients. However, overt nephropathy is rare in childhood; screening and ongoing assessment for the earliest manifestation of renal injury is extremely important in this young population, as well. Although in the past decades intensive research activity focused on understanding of the pathomechanism of diabetic nephropathy and invention of new therapeutic approaches, prevention and definitive care are still urgently needed. The clinical section of the article summarizes the present state of epidemiology, diagnosis and current therapies of childhood diabetic nephropathy. Then, the authors discuss the state of basic research and show a few promising targets for drug development.

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.

Gender differences in serum and glucocorticoid regulated kinase-1 (SGK-1) expression during renal ischemia/reperfusion injury

Several studies reported sexual dimorphism in the signaling mechanisms of renal ischemia/reperfusion (I/R). The anti-apoptotic serum and glucocorticoid-regulated kinase-1 (SGK-1) is up-regulated and has a significant protective role in renal I/R. SGK-1 has several target molecules, and inhibition of the inducible nitric oxide synthase (iNOS) transcription is one of its effector mechanisms. The objective of the present study was to examine if there is a gender-specific expression and activation of SGK-1 during renal I/R injury. In vitro, treatment of HK-2 kidney proximal tubular cells with different concentrations of 17-beta estradiol had no effect, whereas testosterone increased SGK-1 abundance in a dose-dependent manner. In vivo, in a rat model of unilateral renal I/R injury, there was a higher SGK-1 expression and phosphorylation in males 2 and 24 h after ischemia paralleled by reduction in the mRNA expression of iNOS compared to females. Deprivation of testosterone by castration of males resulted in decreased SGK-1 protein level at all time-points and reduced phosphorylation 2 and 24 h after reperfusion. Our results suggest that testosterone up-regulates SGK-1 in the kidney contributing to sexual dimorphisms in the cell signalling machinery. The significance of the testosterone-regulated SGK-1 level and activity in the kidney needs further investigations.