Increased Act1/IL-17R expression in Hirschsprung’s disease

Purpose

Hirschsprung’s disease-associated enterocolitis (HAEC) is the most common cause of morbidity and mortality in Hirschsprung’s disease (HSCR). Altered intestinal epithelial barrier function is implicated in the pathogenesis of HAEC. IL-17 is a proinflammatory cytokine that plays a crucial role in host defense against microbial organisms in the development of inflammatory diseases. Act1 is an essential adaptor molecule required for the IL-17-mediated inflammatory responses via interaction with IL-17 receptor (IL-17R). We designed this study to investigate the hypothesis that Act1/Il-17R expression is upregulated in HSCR.

Methods

We investigated Act1 and IL17R expression in ganglionic andaganglionic bowel of HD patients (n = 10) and controls (n = 10). qPCR, Western blotting and confocal immunofluorescence were performed.

Main results

qPCR and Western blot analysis revealed that Act1 and IL17R are strongly expressed in the aganglionic and ganglionic colon of patients with HSCR. Act1 and IL17R expression was significantly increased in HSCR specimens compared to controls (p < 0.05). Confocal microscopy revealed a markedly increased expression of Act1 and IL17R in the colonic epithelium of patients with HSCR compared to controls.

Conclusion

To our knowledge, we report, for the first time, the expression of Act1 in the human colon. The increased expression of Act1 and Il-17 in the aganglionic and ganglionic bowel in HSCR may result in IL-17-mediated increased inflammatory response leading to the development of HAEC

     

Mesenchymal expression of the <Emphasis Type="Italic">FRAS1/FREM2</Emphasis> gene unit is decreased in the developing fetal diaphragm of nitrofen-induced congenital diaphragmatic hernia

Purpose

Developmental mutations that inhibit normal formation of extracellular matrix (ECM) in fetal diaphragms have been identified in congenital diaphragmatic hernia (CDH). FRAS1 and FRAS1-related extracellular matrix 2 (FREM2), which encode important ECM proteins, are secreted by mesenchymal cells during diaphragmatic development. The FRAS1/FREM2 gene unit has been shown to form a ternary complex with FREM1, which plays a crucial role during formation of human and rodent diaphragms. Furthermore, it has been demonstrated that the diaphragmatic expression of FREM1 is decreased in the nitrofen-induced CDH model. We hypothesized that FRAS1 and FREM2 expression is decreased in the developing diaphragms of fetal rats with nitrofen-induced CDH.

Methods

Pregnant rats were exposed to either nitrofen or vehicle on gestational day 9 (D9), and fetuses were harvested on D13, D15 and D18. Microdissected diaphragms were divided into nitrofen-exposed/CDH and control samples (n = 12 per time-point and experimental group, respectively). Diaphragmatic gene expression levels of FRAS1 and FREM2 were analyzed by qRT-PCR. Immunofluorescence double staining for FRAS1 and FREM2 was combined with the mesenchymal marker GATA4 in order to evaluate protein expression and localization in pleuroperitoneal folds (PPFs) and fetal diaphragmatic tissue.

Results

Relative mRNA expression of FRAS1 and FREM2 were significantly reduced in PPFs of nitrofen-exposed fetuses on D13 (1.76 ± 0.86 vs. 3.09 ± 1.15; p < 0.05 and 0.47 ± 0.26 vs. 0.82 ± 0.36; p < 0.05), developing diaphragms of nitrofen-exposed fetuses on D15 (1.45 ± 0.80 vs. 2.63 ± 0.84; p < 0.05 and 0.41 ± 0.16 vs. 1.02 ± 0.49; p < 0.05) and fully muscularized diaphragms of CDH fetuses on D18 (1.35 ± 0.75 vs. 2.32 ± 0.92; p < 0.05 and 0.37 ± 0.24 vs. 0.70 ± 0.32; p < 0.05) compared to controls. Confocal laser scanning microscopy revealed markedly diminished FRAS1 and FREM2 immunofluorescence in diaphragmatic mesenchyme, which was associated with reduced proliferation of mesenchymal cells in nitrofen-exposed PPFs and fetal CDH diaphragms on D13, D15 and D18 compared to controls.

Conclusion

Decreased mesenchymal expression of FRAS1 and FREM2 in the nitrofen-induced CDH model may cause failure of the FRAS1/FREM2 gene unit to activate FREM1 signaling, disturbing the formation of diaphragmatic ECM and thus contributing to the development of diaphragmatic defects in CDH.

     

Epithelioid hemangioma of the temporal artery: a case report

Temporal or giant cell arteritis is the most common vasculitis affecting the temporal artery. We encountered an unusual case of involvement of the temporal artery, which showed marked proliferating capillaries admixed with a dense infiltrate of eosinophils affecting all layers of the vessel. It was concluded that these changes were those of an epithelioid hemangioma of the temporal artery.     

Inhibition of agonist-induced down-regulation of the delta-opioid receptor with a proteasome inhibitor attenuates opioid tolerance in human embryonic kidney 293 cells

This study was designed to test the hypothesis that inhibition of agonist-induced delta-receptor down-regulation would block the development of opioid tolerance in a cell-based model. A human embryonic kidney 293 cell line was established that expressed an epitope-tagged delta-opioid receptor (DOR). Treatment of DOR cells with Tyr-d-Ala-Gly-Phe-d-Leu-enkephalin (DADL) resulted in a time-dependent decrease in the B(max) of delta-opioid receptor binding sites and immunoreactive receptor protein. When cells were coincubated with the proteasome inhibitor N-benzyloxycarbonyl-l-leucyl-l-leucyl-l-leucinal (ZLLL) and DADL, the magnitude of the agonist-induced decrease in B(max) and immunoreactive receptor protein was reduced compared with DADL treatment alone. Acute treatment of DOR cells with DADL caused a 3-fold increase in the level of phosphorylated mitogen-activated protein (MAP) kinase. Prior exposure of DOR cells to DADL completely abrogated the agonist-induced activation of MAP kinase. When DOR cells were coincubated with DADL and ZLLL, the proteasome inhibitor prevented the loss of agonist activation of MAP kinase. Acute treatment of DOR cell membranes with DADL stimulated [(35)S]guanosine 5'-3-O-(thio-)triphosphate (GTPgammaS) binding. When DOR cells were preincubated with DADL, the agonist-induced increase in [(35)S]GTPgammaS binding was attenuated. Coincubation of ZLLL and agonist partially prevented the decreased responsiveness to agonist stimulation. The results of this study demonstrated that inhibition of agonist-induced down regulation with a proteasome inhibitor attenuated opioid tolerance in a cellular model, and suggest that coadministration of a proteasome inhibitor with chronic opioid agonist treatment may be useful for limiting opioid tolerance in vivo.