Prolonged morphine treatment alters δ opioid receptor post-internalization trafficking

BACKGROUND AND PURPOSE

The δ opioid receptor (DOP receptor) undergoes internalization both constitutively and in response to agonists. Previous work has shown that DOP receptors traffic from intracellular compartments to neuronal cell membranes following prolonged morphine treatment. Here, we examined the effects of prolonged morphine treatment on the post-internalization trafficking of DOP receptors.

EXPERIMENTAL APPROACH

Using primary cultures of dorsal root ganglia neurons, we measured the co-localization of endogenous DOP receptors with post-endocytic compartments following both prolonged and acute agonist treatments.

KEY RESULTS

A departure from the constitutive trafficking pathway was observed following acute DOP receptor agonist-induced internalization by deltorphin II. That is, the DOP receptor underwent distinct agonist-induced post-endocytic sorting. Following prolonged morphine treatment, constitutive DOP receptor trafficking was augmented. SNC80 following prolonged morphine treatment also caused non-constitutive DOP receptor agonist-induced post-endocytic sorting. The μ opioid receptor (MOP receptor) agonist DAMGO induced DOP receptor internalization and trafficking following prolonged morphine treatment. Finally, all of the alterations to DOP receptor trafficking induced by both DOP and MOP receptor agonists were inhibited or absent when those agonists were co-administered with a DOP receptor antagonist, SDM-25N.

CONCLUSIONS AND IMPLICATIONS

The results support the hypothesis that prolonged morphine treatment induces the formation of MOP–DOP receptor interactions and subsequent augmentation of the available cell surface DOP receptors, at least some of which are in the form of a MOP/DOP receptor species. The pharmacology and trafficking of this species appear to be unique compared to those of its individual constituents.

LINKED ARTICLES

This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2

FoxO mediates APP-induced AICD-dependent cell death

The amyloid precursor protein (APP) is a broadly expressed transmembrane protein that has a significant role in the pathogenesis of Alzheimer's disease (AD). APP can be cleaved at multiple sites to generate a series of fragments including the amyloid β (Aβ) peptides and APP intracellular domain (AICD). Although Aβ peptides have been proposed to be the main cause of AD pathogenesis, the role of AICD has been underappreciated. Here we report that APP induces AICD-dependent cell death in Drosophila neuronal and non-neuronal tissues. Our genetic screen identified the transcription factor forkhead box O (FoxO) as a crucial downstream mediator of APP-induced cell death and locomotion defect. In mammalian cells, AICD physically interacts with FoxO in the cytoplasm, translocates with FoxO into the nucleus upon oxidative stress, and promotes FoxO-induced transcription of pro-apoptotic gene Bim. These data demonstrate that APP modulates FoxO-mediated cell death through AICD, which acts as a transcriptional co-activator of FoxO.

Different expression of miRNAs in early esophageal squamous cell carcinoma with differential prognosis

Patients at the same pathological stage of early esophageal squamous cell carcinoma (ESCC) have significantly different prognoses. The aim of this study was to explore the relationship between specific microRNAs (miRNAs) in two groups of early ESCC patients who had different prognoses at the pT1N0 stage, and to study the prognostic significance of different miRNAs in early ESCC metastasis. We tried to identify prognostic markers that may be helpful in the selection of appropriate treatment for patients with early ESCC. We used TaqMan Human miRNA Arrays to detect and analyze bioinformatically the expression profiles of miRNAs in two groups, and the reverse transcription polymerase chain reaction method to verify the differences in miRNA expression. The miRNA arrays revealed a total of 29 markedly downregulated miRNAs in the survival group compared with the deceased group. Such miRNAs were associated with lympho-vascular invasion and metastasis, and acted as predictive markers of lympho-vascular invasion and metastasis. The detection of these miRNAs forms an important basis for the treatment of early ESCC. It can also help determine those patients with early ESCC who are good candidates for endoscopic resection treatment and those who need additional treatment after endoscopic resection.

A novel large deletion of the DOCK8 gene in a Chinese family with autosomal-recessive hyper-IgE syndrome

BACKGROUND

Autosomal-recessive hyper-IgE syndrome (AR-HIES; OMIM 243700) is a rare primary immunodeficiency disorder mainly caused by mutations in the dedicator of cytokinesis-8 (DOCK8) gene. DOCK8 is highly expressed in the immune system and plays important roles in regulation of lymphocyte functions.

OBJECTIVE

We analysed the molecular basis of AR-HIES in a Chinese family.

METHODS

A Chinese pedigree of typical AR-HIES was subjected to mutation detection in the DOCK8 gene. All exons of the DOCK8 gene and adjacent exon-intron border sequences were amplified using polymerase chain reaction and directly sequenced.

RESULTS

We identified a novel large deletion of 1481 bp in the DOCK8 gene, encompassing the totality of exon 11 (c.1126_1285del).

CONCLUSION

Our data expand the spectrum of mutations in the DOCK8 gene underlying AR-HIES.

Design of an ultrahigh-energy-resolution and wide-energy-range soft X-ray beamline

A new ultrahigh-energy-resolution and wide-energy-range soft X-ray beamline has been designed and is under construction at the Shanghai Synchrotron Radiation Facility. The beamline has two branches: one dedicated to angle-resolved photoemission spectroscopy (ARPES) and the other to photoelectron emission microscopy (PEEM). The two branches share the same plane-grating monochromator, which is equipped with four variable-line-spacing gratings and covers the 20-2000 eV energy range. Two elliptically polarized undulators are employed to provide photons with variable polarization, linear in every inclination and circular. The expected energy resolution is approximately 10 meV at 1000 eV with a flux of more than 3 × 10(10) photons s(-1) at the ARPES sample positions. The refocusing of both branches is based on Kirkpatrick-Baez pairs. The expected spot sizes when using a 10 µm exit slit are 15 µm × 5 µm (horizontal × vertical FWHM) at the ARPES station and 10 µm × 5 µm (horizontal × vertical FWHM) at the PEEM station. The use of plane optical elements upstream of the exit slit, a variable-line-spacing grating and a pre-mirror in the monochromator that allows the influence of the thermal deformation to be eliminated are essential for achieving the ultrahigh-energy resolution.

Sos recruitment system for the analysis of the interaction between sulfatase-modifying factor 2 subtypes and interleukin-13

Interleukin (IL)-13 is a central mediator in allergic asthma. Our previous results have indicated that sulfatase-modifying factor 2 (SUMF2) interacts with IL-13 and inhibits its secretion. In this study, we investigated the interactions between SUMF2 subtypes and 2 types of IL-13. Wild type IL-13 (wh-IL-13) and its mutated counterpart (mh-IL-13) were analyzed and cloned into pSos yeast expression vectors. Protein was expressed in host cdc25H yeast strains. A quartet of agar growth plates was prepared for the yeast two-hybrid system, which was used to detect IL-13 and SUMF2 subtype interactions. Both yeast expression vectors, pSos/whIL-13 and pSos/whIL-13, and recombinant expression vectors for the 5 subtypes of SUMF2 (pMyr/SUMF2-Vx) were constructed. Our data showed that all of the SUMF2 subtypes bound to whIL-13 and mhIL-13 in the CytoTrap system. Five SUMF2 subtypes - SUMF2-V2, SUMF2-V3, SUMF2-V4, SUMF2-V5, and SUMF2-V7--interacted with whIL-13 and mhIL-13. These subtypes may contribute to allergic asthma by mediating IL-13 release.

The evaluation of Lugol's iodine solution staining combined with endoscope for diagnosis of non-erosive reflux disease in clinic

AIM

To evaluate the value of Lugol's iodine solution staining combined with endoscope on the diagnosis of non-erosive reflux disease (NERD).

PATIENTS AND METHODS

A total of 96 gastroesophageal reflux disease patients were selected to participate in this study. The patients were stained on esophageal mucosa by Lugol's iodine solution and examined at routine endoscopy. The shallow staining and/or non-staining group patients were treated with esomeprazole and mosapride citrate, and then the changes in Lugol's iodine staining, Gerd Q (Gerd questionnaire) scoring and histological characters of esophageal mucosa were recorded before and after treatment.

RESULTS

As the results, a total of 68 patients were diagnosed as NERD, and 36 of 68 patients were observed with uniform staining and 32 of 68 patients were observed with shallow staining and/or non-staining. After 4 weeks for treatment, 28 of 32 patients with shallow staining and/or non-staining became uniform staining and 4 of 32 patients were still with shallow staining and/or non-staining. Before and after treatment, the Gerd Q scoring of uniform staining groups and shallow staining and/or non-staining groups all had a significant difference (p < 0.05). Compared to the routine endoscopy, the detection rate of abnormal esophageal mucosa was significantly increased by Lugol's iodine solution staining combined with endoscope.

CONCLUSIONS

Lugol's iodine solution staining combined with routine endoscopy, Gerd Q scoring and histomorphology can be used to evaluate the diagnosis and therapeutic effect of NERD.

Bendless modulates JNK-mediated cell death and migration in Drosophila

The TNF-JNK pathway is a highly conserved signaling pathway that regulates a wide spectrum of biological processes including cell death and migration. To further delineate this pathway, we carried out a genetic screen for dominant modifiers of the cell death phenotype triggered by ectopic expression of Eiger (Egr), the Drosophila TNF ortholog. Here we show that Bendless (Ben), an E2 ubiquitin-conjugating enzyme, modulates Egr-induced JNK activation and cell death through dTRAF2. Furthermore, Ben physically interacts with dTRAF2 and regulates Egr-induced dTRAF2 polyubiquitination. Finally, Ben is required for JNK-dependent tumor progression, cell migration, oxidative stress resistance and longevity. Our results indicate that Ben constitutes an essential component of the evolutionarily conserved TNF-JNK pathway that modulates cell death and invasion, tumor progression, stress response and lifespan in metazoans.

Src42A modulates tumor invasion and cell death via Ben/dUev1a-mediated JNK activation in Drosophila

Loss of the cell polarity gene could cooperate with oncogenic Ras to drive tumor growth and invasion, which critically depends on the c-Jun N-terminal Kinase (JNK) signaling pathway in Drosophila. By performing a genetic screen, we have identified Src42A, the ortholog of mammalian Src, as a key modulator of both Ras^V12/lgl^−/− triggered tumor invasion and loss of cell polarity gene-induced cell migration. Our genetic study further demonstrated that the Bendless (Ben)/dUev1a ubiquitin E2 complex is an essential regulator of Src42A-induced, JNK-mediated cell migration. Furthermore, we showed that ectopic Ben/dUev1a expression induced invasive cell migration along with increased MMP1 production in wing disc epithelia. Moreover, Ben/dUev1a could cooperate with Ras^V12 to promote tumor overgrowth and invasion. In addition, we found that the Ben/dUev1a complex is required for ectopic Src42A-triggered cell death and endogenous Src42A-dependent thorax closure. Our data not only provide a mechanistic insight into the role of Src in development and disease but also propose a potential oncogenic function for Ubc13 and Uev1a, the mammalian homologs of Ben and dUev1a.

Measurement of J/ψ azimuthal anisotropy in Au+Au collisions at sqrt[s(NN)]=200 GeV

The measurement of J/ψ azimuthal anisotropy is presented as a function of transverse momentum for different centralities in Au+Au collisions at sqrt[s(NN)]=200 GeV. The measured J/ψ elliptic flow is consistent with zero within errors for transverse momentum between 2 and 10 GeV/c. Our measurement suggests that J/ψ particles with relatively large transverse momenta are not dominantly produced by coalescence from thermalized charm quarks, when comparing to model calculations.

Probe of the solar magnetic field using the "cosmic-ray shadow" of the sun

We report on a clear solar-cycle variation of the Sun’s shadow in the 10 TeV cosmic-ray flux observed by the Tibet air shower array during a full solar cycle from 1996 to 2009. In order to clarify the physical implications of the observed solar cycle variation, we develop numerical simulations of the Sun’s shadow, using the potential field source surface model and the current sheet source surface (CSSS) model for the coronal magnetic field. We find that the intensity deficit in the simulated Sun’s shadow is very sensitive to the coronal magnetic field structure, and the observed variation of the Sun’s shadow is better reproduced by the CSSS model. This is the first successful attempt to evaluate the coronal magnetic field models by using the Sun’s shadow observed in the TeV cosmic-ray flux.

[Phosphorylation-independent desensitization of metabotropic glutamate receptor 5 by G protein-coupled receptor kinase 2 in HEK 293 cells]

The metabotropic glutamate receptor 5 (mGluR5) is one of the important excitatory neurotransmitter receptors in the central nervous system, and its desensitization by G protein-coupled receptor kinases (GRKs) plays an important role in neuron protection against receptor overstimulation. It is reported that GRK2 could down-regulate the mGluR5 signaling in both HEK 293 cells and neurons. However, whether GRK2-mediated mGluR5 desensitization is phosphorylation dependent remains controversial. Here, we demonstrated that the signal intensity and kinetics of mGluRS desensitization was inhibited or changed by GRK2 in HEK 293 cells. By using the catalytically inactive GRK2 mutant K220R, and the receptor mutants that lack potential phosphorylation sites in the C-terminal tail, we demonstrated that the GRK2-mediated mGluR5 desensitization was phosphorylation-independent. Furthermore, overexpression of an N-terminal regulator of G protein signaling (RGS) homology (RH) domain of GRK2 was sufficient to attenuate the mGluR5 signaling, whereas the expression of GRK2 D110A mutant devoid in Galphaq binding was unable to inhibit mGluRS signaling. In summary, this study provides evidence that GRK2 mediates phosphorylation-independent mGluR5 desensitization via the interaction between the RGS domain and Galphaq in HEK 293 cells.

A simple and novel method for GII norovirus genome clone with generic primers

AIMS

This study aims to establish a novel method for cloning GII norovirus genome using generic primers rationally designed based on multiple alignments of 96 GII norovirus genome sequences.

METHODS AND RESULTS

Based on conservative analysis of 96 GII norovirus genome sequences available in GenBank, three fragments encompassing the full-length genome were rationally designed. Fragments A, B and C were amplified by primers N1F/N2819R, N2689F/COG2R and COG2F/adaptor, respectively. Meanwhile, the sensitivity of the novel primers was evaluated, which could achieve 10(1) RTPCRU, as determined by the common detection primer pair JV12/JV13. The availability of the novel protocol was verified by sequencing two norovirus strains with different genotypes.

CONCLUSIONS

Primers for GII norovirus genome clone were rationally designed, and a novel GII genome clone method was established.

SIGNIFICANCE AND IMPACT OF THE STUDY

The three-fragment cloning method can be used as a universal tool to collect information on the genome of norovirus strains for future evolution and antivirus studies.

Observation of an energy-dependent difference in elliptic flow between particles and antiparticles in relativistic heavy ion collisions

Elliptic flow (v(2)) values for identified particles at midrapidity in Au + Au collisions, measured by the STAR experiment in the beam energy scan at RHIC at sqrt[s(NN)] = 7.7-62.4 GeV, are presented. A beam-energy-dependent difference of the values of v(2) between particles and corresponding antiparticles was observed. The difference increases with decreasing beam energy and is larger for baryons compared to mesons. This implies that, at lower energies, particles and antiparticles are not consistent with the universal number-of-constituent-quark scaling of v(2) that was observed at sqrt[s(NN)] = 200 GeV.

Comparison of FIB-4 and APRI in Chinese HBV-infected patients with persistently normal ALT and mildly elevated ALT

Significant liver disease has been reported in chronic hepatitis B patients with normal alanine aminotransferase (ALT). Liver biopsy (LB) is the current gold standard for assessing hepatic inflammation and fibrosis in patients with chronic HBV. However, associated risks have led to the development of noninvasive models. Their utility in patients with normal ALT is unknown. FIB-4 and aspartate aminotransferase (AST)-to-platelet ratio index (APRI) were calculated for patients with chronic HBV infection undergoing biopsy. The performance of each model and AUROC for predicting significant fibrosis (Scheuer's score ≥ S2) were determined for the entire cohort and stratified by elevated (≥50 U/L) and normal ALT. Two-hundred and thirty-one liver biopsies were included. The number of patient with normal ALT was 140, and 22.1% had significant fibrosis. The AUROC curve for patients with normal ALT was 0.81 for FIB-4 and 0.80 for APRI, compared with 0.71 for FIB-4 and 0.72 for APRI for those with mildly elevated ALT level. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of FIB-4 were 0.63, 0.88, 0.61 and 0.93, for patients with normal ALT; the values for APRI were 0.40, 0.88, 0.33 and 0.93. Both FIB-4 and APRI are useful for identification of those without significant fibrosis. However, because they have poor PPV, LB will continue to be used for assessment of HBV-infected patients with normal ALT and mildly elevated ALT.

Prospective feasibility study on the use of multiband mucosectomy for endoscopic resection of early squamous neoplasia in the esophagus

BACKGROUND AND STUDY AIMS

Endoscopic resection for esophageal squamous high-grade intraepithelial neoplasia (HGIN) or intramucosal cancer (esophageal squamous cell carcinoma [ESCC]) with the endoscopic resection cap technique is technically difficult, and requires submucosal lifting and multiple snares for piecemeal resections. Multiband mucosectomy (MBM) is an easy-to-use endoscopic resection technique and may be the modality of choice in China, where ESCC is extremely prevalent. The aim of the current study was to prospectively evaluate MBM for piecemeal endoscopic resection of squamous neoplasia of the esophagus.

METHODS

Patients with HGIN/ESCC and no signs of submucosal invasion or metastatic disease were included in the study. Lesions were delineated using electrocoagulation and resected using the MBM technique. Endpoints were procedure time, endoscopic radicality, complications, histology of the endoscopic resection specimens, and absence of HGIN/ESCC at the endoscopic resection scar during follow-up.

RESULTS

A total of 41 patients (26 male; mean age 61 years) underwent MBM; all lesions were visible with white light endoscopy (median length 5 cm, interquartile range [IQR] 4 - 6 cm; median circumferential extent 42 %, IQR 25 - 50 %). Median procedure time was 12 minutes (IQR 8 - 24 minutes). Median number of resections was 5 (IQR 3 - 6). Endoscopic complete resection was achieved in all lesions. There was one perforation, which was treated by application of clips. No other complications were observed. The worst histology was ESCC (n = 19), HGIN (n = 17), middle grade intraepithelial neoplasia (n = 4), and normal squamous epithelium (n = 1). Endoscopic follow-up at 3 months showed HGIN at the endoscopic resection scar in two patients, which was effectively treated endoscopically, and showed normal squamous epithelium in all patients at final follow-up (median 15 months, IQR 12 - 24 months).

CONCLUSION

This first prospective study on MBM for piecemeal endoscopic resection of early esophageal squamous neoplasia showed that MBM was effective for the complete removal of lesions with short procedure time, few complications, effective histological assessment of resected specimens, and durable treatment effect.