Impact of typhoon events on microplastic distribution in offshore sediments in Leizhou Peninsula of the South China Sea

Microplastic is an emerging pollutant and a technical fossil in Anthropocene sediments. Typhoon frequency and intensity have increased due to climate change, which has a major effect on the distribution patterns of microplastics. It is still unknown, though, how the topography of the peninsula affects the reconstruction of the distribution of microplastic in typhoons. Due to frequent typhoons, the Leizhou Peninsula (LZP) in the north part of the South China Sea is an ideal place to study the impact of topographic variations on microplastic distribution during typhoon events. This study investigated microplastics ranging in size from 50 μm to 5 mm in sediment. Microscopic inspection and μ-FTIR tests were used to identify microplastic characteristics from offshore surface sediments before and after typhoons. The average microplastic abundance in offshore sediments decreased from 18 ± 17 items/kg to 15 ± 15 items/kg after typhoons. Results show that typhoons only increase the microplastic abundance in topographically protected areas along the northeast coast of LZP, with no significant difference observed in other regions. The influence of typhoon on the morphological characteristics of microplastics in sediments is more pronounced and widespread, as evidenced by a shift in the predominant shape of microplastics from fibers to fragments and a decrease in size accompanied by an increased abundance within the 100 μm-1 mm fraction. The color of microplastics remained similar before and after typhoons, and the polymer composition of microplastics became more uniform. The alteration of microplastic morphology may be attributed to the enhancement of wave intensity induced by typhoons. This study enhances the comprehension of typhoon-induced impacts on pollutant redistribution, specifically microplastics, thereby providing essential empirical evidence and theoretical foundations for pollution regulation.

Dynamic nucleolar phase separation influenced by non-canonical function of LIN28A instructs pluripotent stem cell fate decisions

LIN28A is important in somatic reprogramming and pluripotency regulation. Although previous studies addressed that LIN28A can repress let-7 microRNA maturation in the cytoplasm, few focused on its role within the nucleus. Here, we show that the nucleolus-localized LIN28A protein undergoes liquid-liquid phase separation (LLPS) in mouse embryonic stem cells (mESCs) and in vitro. The RNA binding domains (RBD) and intrinsically disordered regions (IDR) of LIN28A contribute to LIN28A and the other nucleolar proteins' phase-separated condensate establishment. S120A, S200A and R192G mutations in the IDR result in subcellular mislocalization of LIN28A and abnormal nucleolar phase separation. Moreover, we find that the naive-to-primed pluripotency state conversion and the reprogramming are associated with dynamic nucleolar remodeling, which depends on LIN28A's phase separation capacity, because the LIN28A IDR point mutations abolish its role in regulating nucleolus and in these cell fate decision processes, and an exogenous IDR rescues it. These findings shed light on the nucleolar function in pluripotent stem cell states and on a non-canonical RNA-independent role of LIN28A in phase separation and cell fate decisions.

A second-generation M1-polarized CAR macrophage with antitumor efficacy

Chimeric antigen receptor (CAR) T cell therapies have successfully treated hematological malignancies. Macrophages have also gained attention as an immunotherapy owing to their immunomodulatory capacity and ability to infiltrate solid tumors and phagocytize tumor cells. The first-generation CD3ζ-based CAR-macrophages could phagocytose tumor cells in an antigen-dependent manner. Here we engineered induced pluripotent stem cell-derived macrophages (iMACs) with toll-like receptor 4 intracellular toll/IL-1R (TIR) domain-containing CARs resulting in a markedly enhanced antitumor effect over first-generation CAR-macrophages. Moreover, the design of a tandem CD3ζ-TIR dual signaling CAR endows iMACs with both target engulfment capacity and antigen-dependent M1 polarization and M2 resistance in a nuclear factor kappa B (NF-κB)-dependent manner, as well as the capacity to modulate the tumor microenvironment. We also outline a mechanism of tumor cell elimination by CAR-induced efferocytosis against tumor cell apoptotic bodies. Taken together, we provide a second-generation CAR-iMAC with an ability for orthogonal phagocytosis and polarization and superior antitumor functions in treating solid tumors relative to first-generation CAR-macrophages.

Metabolic Reprogramming via ACOD1 depletion enhances function of human induced pluripotent stem cell-derived CAR-macrophages in solid tumors

The pro-inflammatory state of macrophages, underpinned by their metabolic condition, is essentially affecting their capacity of combating tumor cells. Here we find, via a pooled metabolic gene knockout CRISPR screen that KEAP1 and ACOD1 are strong regulators of the pro-inflammatory state in macrophages. We show that ACOD1 knockout macrophages, generated in our induced pluripotent stem cell-derived CAR-macrophage (CAR-iMAC) platform, are strongly and persistently polarized toward the pro-inflammatory state, which manifests in increased reactive oxygen species (ROS) production, more potent phagocytosis and enhanced cytotoxic functions against cancer cells in vitro. In ovarian or pancreatic cancer mouse models, ACOD1-depleted CAR-iMACs exhibit enhanced capacity in repressing tumors, leading to increased survival. In addition, combining ACOD1-depleted CAR-iMACs with immune checkpoint inhibitors (ICI), such as anti-CD47 or anti-PD1 antibodies, result in even stronger tumor suppressing effect. Mechanistically, the depletion of ACOD1 reduces levels of the immuno-metabolite itaconate, allowing KEAP1 to prevent NRF2 from entering the nucleus to activate an anti-inflammatory program. This study thus lays down the proof of principle for targeting ACOD1 in myeloid cells for cancer immunotherapy and introduces metabolically engineered human iPSC-derived CAR-iMACs cells with enhanced polarization and anti-tumor functions in adoptive cell transfer therapies.

Macrophage-Based Combination Therapies as a New Strategy for Cancer Immunotherapy

BACKGROUND

Cells of the immune system can inhibit tumor growth and progression; however, immune cells can also promote tumor cell growth, survival, and angiogenesis as a result of the immunosuppressive microenvironments. In the last decade, a growing number of new therapeutic strategies focused on reversing the immunosuppressive status of tumor microenvironments (TMEs), to reprogram the TME to be normal, and to further activate the antitumor functions of immune cells. Most of the "hot tumors" are encompassed with M2 macrophages promoting tumor growth, and the accumulation of M2 macrophages into tumor islets leads to poor prognosis in a wide variety of tumors.

SUMMARY

Therefore, how to uncover more immunosuppressive signals and to reverse the M2 tumor-associated macrophages (TAMs) to M1-type macrophages is essential for reversing the immunosuppressive state. Except for reeducation of TAMs in the cancer immunotherapy, macrophages as central effectors and regulators of the innate immune system have the capacity of phagocytosis and immune modulation in macrophage-based cell therapies.

KEY MESSAGES

We review the current macrophage-based cell therapies that use genetic engineering to augment macrophage functionalities with antitumor activity for the application of novel genetically engineered immune cell therapeutics. A combination of TAM reeducation and macrophage-based cell strategy may bring us closer to achieving the original goals of curing cancer. In this review, we describe the characteristics, immune status, and tumor immunotherapy strategies of macrophages to provide clues and evidences for future macrophage-based immune cell therapies.

rRNA biogenesis regulates mouse 2C-like state by 3D structure reorganization of peri-nucleolar heterochromatin

The nucleolus is the organelle for ribosome biogenesis and sensing various types of stress. However, its role in regulating stem cell fate remains unclear. Here, we present evidence that nucleolar stress induced by interfering rRNA biogenesis can drive the 2-cell stage embryo-like (2C-like) program and induce an expanded 2C-like cell population in mouse embryonic stem (mES) cells. Mechanistically, nucleolar integrity maintains normal liquid-liquid phase separation (LLPS) of the nucleolus and the formation of peri-nucleolar heterochromatin (PNH). Upon defects in rRNA biogenesis, the natural state of nucleolus LLPS is disrupted, causing dissociation of the NCL/TRIM28 complex from PNH and changes in epigenetic state and reorganization of the 3D structure of PNH, which leads to release of Dux, a 2C program transcription factor, from PNH to activate a 2C-like program. Correspondingly, embryos with rRNA biogenesis defect are unable to develop from 2-cell (2C) to 4-cell embryos, with delayed repression of 2C/ERV genes and a transcriptome skewed toward earlier cleavage embryo signatures. Our results highlight that rRNA-mediated nucleolar integrity and 3D structure reshaping of the PNH compartment regulates the fate transition of mES cells to 2C-like cells, and that rRNA biogenesis is a critical regulator during the 2-cell to 4-cell transition of murine pre-implantation embryo development.

LIN28 coordinately promotes nucleolar/ribosomal functions and represses the 2C-like transcriptional program in pluripotent stem cells

LIN28 is an RNA binding protein with important roles in early embryo development, stem cell differentiation/reprogramming, tumorigenesis and metabolism. Previous studies have focused mainly on its role in the cytosol where it interacts with Let-7 microRNA precursors or mRNAs, and few have addressed LIN28's role within the nucleus. Here, we show that LIN28 displays dynamic temporal and spatial expression during murine embryo development. Maternal LIN28 expression drops upon exit from the 2-cell stage, and zygotic LIN28 protein is induced at the forming nucleolus during 4-cell to blastocyst stage development, to become dominantly expressed in the cytosol after implantation. In cultured pluripotent stem cells (PSCs), loss of LIN28 led to nucleolar stress and activation of a 2-cell/4-cell-like transcriptional program characterized by the expression of endogenous retrovirus genes. Mechanistically, LIN28 binds to small nucleolar RNAs and rRNA to maintain nucleolar integrity, and its loss leads to nucleolar phase separation defects, ribosomal stress and activation of P53 which in turn binds to and activates 2C transcription factor Dux. LIN28 also resides in a complex containing the nucleolar factor Nucleolin (NCL) and the transcriptional repressor TRIM28, and LIN28 loss leads to reduced occupancy of the NCL/TRIM28 complex on the Dux and rDNA loci, and thus de-repressed Dux and reduced rRNA expression. Lin28 knockout cells with nucleolar stress are more likely to assume a slowly cycling, translationally inert and anabolically inactive state, which is a part of previously unappreciated 2C-like transcriptional program. These findings elucidate novel roles for nucleolar LIN28 in PSCs, and a new mechanism linking 2C program and nucleolar functions in PSCs and early embryo development.

Mental distress among adult patients with eosinophilic esophagitis

RATIONALE

Data on the prevalence of mental distress among adult eosinophilic esophagitis (EoE) patients are scarce. Also, a significant gap remains in the understanding of which determinants are related to significant psychological symptoms and whether distressed patients require and receive mental care.

METHODS

Adult EoE patients were invited to complete standardized measures on anxiety/depressive symptoms (HADS) and general psychopathology (SCL-90-R). All scores were compared to general population norms. Socio-demographic and clinical factors were assessed.

RESULTS

In total, 147 adult EoE patients (61% males, age 43 (IQR 29-52) years were included (response rate 71%). No difference with general population values was found for total anxiety and depressive symptoms (7.8 ± 6.6 vs. 8.4 ± 6.3; p = 0.31). A total of 38/147(26%) patients reported high levels of anxiety and/or depressive symptoms (HADS-A ≥ 8: 35/147(24%) and HADS-D ≥ 8: 14/147(10%)), indicative of a possible psychiatric disorder. In a multivariate analysis, age between 18-35 years was independently associated with high levels of anxiety (HADS-A ≥ 8) (OR 3.0, 95% CI 1.3-6.9; p = 0.01). The SCL-90-R Global Severity Index (GSI) was significantly higher compared to the general population (p < 0.001). Significant signs of general mental distress (GSI ≥ 80th percentile) were observed in 51(36%) EoE patients, of which 29(57%) patients denied having any mental problems and only 8(16%) patients received mental care.

CONCLUSION

A considerable proportion of adult EoE patients suffers from mental distress, with a 3-fold risk of significant anxiety in those patients younger than 35 years. Therefore, population-based studies are required and a proactive approach in the screening for and treatment of these psychological symptoms in EoE practice seems essential.

POS0089 AZD9567 VERSUS PREDNISOLONE IN PATIENTS WITH ACTIVE RHEUMATOID ARTHRITIS: A PHASE 2A, RANDOMISED, DOUBLE-BLIND, PARALLEL-GROUP EFFICACY AND SAFETY STUDY

Background:

Oral corticosteroids such as prednisolone are potent anti-inflammatory drugs but their use is limited by side effects caused by unwanted actions on the glucocorticoid receptor (GR), such as increased insulin resistance, and off-target actions on the mineralocorticoid receptor (MR) that disrupt electrolyte balance and increase water retention. AZD9567 is an oral, selective, non-steroidal glucocorticoid receptor modulator being developed to treat inflammatory diseases. Pre-clinical and phase 1 clinical data indicate that AZD9567 is the first GR modulator with an improved efficacy–dysglycaemic side effect profile versus prednisolone.

Objectives:

To compare the efficacy, safety and tolerability of AZD9567 with prednisolone in patients with active rheumatoid arthritis (RA), at doses with predicted equivalent anti-inflammatory activity.

Methods:

In this phase 2a, randomised, double-blind, parallel-group, multicentre study in RA patients with DAS28-CRP ≥ 3.2 despite stable treatment with conventional disease-modifying anti-rheumatic therapies (NCT03368235), patients were randomised 1:1 to AZD9567 40 mg or prednisolone 20 mg orally once daily for 14 days. The primary endpoint was change from baseline in DAS28-CRP at day 15. Secondary outcomes included components of DAS28-CRP, TJC68, SJC66, ACR response (ACR20, ACR50, ACR70) and safety outcomes, including serum electrolytes.

Results:

All 21 randomised patients (AZD9567, n = 11; prednisolone, n = 10) completed the study. There was a slight imbalance between the treatment groups at baseline, with higher age (mean ± SD: 64.5 ± 8.4 vs 55.5 ± 13.6 years), more women (8 vs 5) and greater disease severity (DAS28-CRP, mean ± SD: 5.26 ± 0.98 vs 4.90 ± 0.74) in the AZD9567 group versus the prednisolone group. There was no statistically significant or clinically meaningful (i.e. > 1.2) difference in change from baseline to day 15 in DAS28-CRP between AZD9567 and prednisolone, although this was numerically lower with AZD9567 (Table 1). Similar results were observed for TJC68, SJC66, CRP and GH (Table 1). The proportions of patients achieving ACR20, 50 and 70 response criteria were similar in both groups, albeit numerically lower with AZD9567. Similar numbers of patients in each group reported treatment-emergent adverse events (AZD9567, n = 10, prednisolone, n = 9); most were mild in severity. One serious adverse event, suicidal depression, was reported after completing AZD9567 treatment. Morning fasting serum sodium/potassium ratio at day 15 was not altered with AZD9567 but was increased from baseline with prednisolone (Figure 1).

Conclusion:

AZD9567 40 mg had a similar efficacy profile to prednisolone 20 mg in patients with active RA. Both drugs were well tolerated, with no new safety signals. Unlike prednisolone, AZD9567 had no effect on serum sodium/potassium ratio, suggesting selectivity of AZD9567 for the GR over the MR. These results support further trials of AZD9567 in patients with inflammatory disease.

Table 1.

Change from baseline to day 15 in clinical disease activity measures.

AZD9567 (n = 11)Prednisolone (n = 10)Comparison(AZD9567 – prednisolone)LSM CFB (SE)95% CILSM CFB (SE)95% CILSMD (SE)95% CIp valueDAS28−CRP score−1.93 (0.35)−2.66, −1.21−2.40 (0.34)−3.11, −1.700.47 (0.46)−0.49, 1.430.315TJC28 score−6.12 (1.25)−8.76, −3.49−6.07 (1.21)−8.61, −3.52−0.05 (1.60)−3.43, 3.320.973SJC28 score−5.14 (0.65)−6.51, −3.76−5.40 (0.63)−6.73, −4.080.26 (0.84)−1.50, 2.030.757GH score−27.7 (7.3)−42.8, −12.5−37.4 (7.1)−52.3, −22.69.8 (9.7)−10.5, 30.10.325CRP, mg/L−10.8 (2.4)−15.9, −5.8−15.6 (2.5)−20.9, −10.34.8 (3.5)−2.5, 12.00.187TJC68 score−9.02 (2.46)−14.21, −3.82−7.90 (2.36)−12.88, −2.91−1.12 (3.12)−7.69, 5.460.724SJC66 score−6.24 (0.89)−8.13, −4.36−6.66 (0.86)−8.48, −4.850.42 (1.14)−1.98, 2.810.717

CFB, change from baseline; CRP, C-reactive protein; DAS28, 28-joint disease activity score; GH, global health; LSM(D), least-squares mean (difference); SJC, swollen joint count; TJC, tender joint count.

Acknowledgements:

Medical writing support was provided by Richard Claes PhD of PharmaGenesis London, London, UK, funded by AstraZeneca, Gothenburg, Sweden in accordance with Good Publication Practice 3 (GPP3) guidelines (http://www.ismpp.org/gpp3).

This study was funded by AstraZeneca. AZD9567 is an investigational medical product with no approved indication.

Disclosure of Interests:

Jacob M. van Laar Consultant of: Honoraria from - Abbvie, Arxx Tx, Galapagos, Gesyntha, Leadiant, Magenta, Roche, Sanofi Genzyme, Grant/research support from: AstraZeneca, Pfizer, Roche, Alejhandra Lei Shareholder of: AstraZeneca., Grant/research support from: Boehringer Ingelheim in 1998, Bristol-Myers Squibb in 1999, Employee of: AstraZeneca. Past employee of Almirall, Grünenthal, Boehringer Ingelheim, CESIF Pharma, Mary Safy-Khan Grant/research support from: Student grant from AstraZeneca 2015-2018., Joachim Almquist Shareholder of: AstraZeneca, Consultant of: AstraZeneca., Employee of: AstraZeneca., Carol Astbury Shareholder of: AstraZeneca., Employee of: AstraZeneca., Maria Belvisi Shareholder of: AstraZeneca., Grant/research support from: AstraZeneca and Chiesi, Employee of: AstraZeneca., Adam Platt Shareholder of: AstraZeneca., Employee of: AstraZeneca., Susanne Prothon Shareholder of: AstraZeneca., Employee of: AstaZeneca., Sara Samuelsson Shareholder of: AstraZeneca, Employee of: AstraZeneca, Petter Svanberg Employee of: AstraZeneca, Christina Keen Shareholder of: AstraZeneca., Employee of: AstraZeneca.

Neural stemness contributes to cell tumorigenicity

Background

Previous studies demonstrated the dependence of cancer on nerve. Recently, a growing number of studies reveal that cancer cells share the property and regulatory network with neural stem/progenitor cells. However, relationship between the property of neural stemness and cell tumorigenicity is unknown.

Results

We show that neural stem/progenitor cells, but not non-neural embryonic or somatic stem/progenitor cell types, exhibit tumorigenicity and the potential for differentiation into tissue types of all germ layers when they are placed in non-native environment by transplantation into immunodeficient nude mice. Likewise, cancer cells capable of tumor initiation have the property of neural stemness because of their abilities in neurosphere formation in neural stem cell-specific serum-free medium and in differentiation potential, in addition to their neuronal differentiation potential that was characterized previously. Moreover, loss of a pro-differentiation factor in myoblasts, which have no tumorigenicity, lead to the loss of myoblast identity, and gain of the property of neural stemness, tumorigenicity and potential for re-differentiation. By contrast, loss of neural stemness via differentiation results in the loss of tumorigenicity. These suggest that the property of neural stemness contributes to cell tumorigenicity, and tumor phenotypic heterogeneity might be an effect of differentiation potential of neural stemness. Bioinformatic analysis reveals that neural genes in general are correlated with embryonic development and cancer, in addition to their role in neural development; whereas non-neural genes are not. Most of neural specific genes emerged in typical species representing transition from unicellularity to multicellularity during evolution. Genes in Monosiga brevicollis, a unicellular species that is a closest known relative of metazoans, are biased toward neural cells.

Conclusions

We suggest that the property of neural stemness is the source of cell tumorigenicity. This is due to that neural biased unicellular state is the ground state for multicellularity and hence cell type diversification or differentiation during evolution, and tumorigenesis is a process of restoration of neural ground state in somatic cells along a default route that is pre-determined by an evolutionary advantage of neural state.

Pluripotent stem cell-derived CAR-macrophage cells with antigen-dependent anti-cancer cell functions

The Chimera antigen receptor (CAR)-T cell therapy has gained great success in the clinic. However, there are still major challenges for its wider applications in a variety of cancer types including lack of effectiveness due to the highly complex tumor microenvironment, and the forbiddingly high cost due to the personalized manufacturing procedures. In order to overcome these hurdles, numerous efforts have been spent focusing on optimizing Chimera antigen receptors, engineering and improving T cell capacity, exploiting features of subsets of T cell or NK cells, or making off-the-shelf universal cells. Here, we developed induced pluripotent stem cells (iPSCs)-derived, CAR-expressing macrophage cells (CAR-iMac). CAR expression confers antigen-dependent macrophage functions such as expression and secretion of cytokines, polarization toward the pro-inflammatory/anti-tumor state, enhanced phagocytosis of tumor cells, and in vivo anticancer cell activity. This technology platform for the first time provides an unlimited source of iPSC-derived engineered CAR-macrophage cells which could be utilized to eliminate cancer cells.

EZH2 Regulates Protein Stability via Recruiting USP7 to Mediate Neuronal Gene Expression in Cancer Cells

Misexpression of chromatin modification factors and changed epigenetic modifications play crucial roles for tumorigenesis. Our previous studies demonstrated that inhibition of epigenetic modification enzymes EZH2, LSD1, DNMTs, and HDACs caused post-mitotic neuron-like differentiation in different cancer cells. However, how they regulate neuronal differentiation in cancer cells was unknown. Here, we show that EZH2, LSD1, DNMT1, and HDAC1 form interactions themselves, meanwhile, they also interact with SMAD proteins and β-CATENIN in cancer cells. Chemical inhibition of these enzymes leads to reduced level of proteins except HDAC1. The change in protein level and/or enzymatic activities further result in changed chromatin modifications on neuronal gene promoters, and activation of neuronal genes. Inhibition of these enzymes in neural progenitor cells (NPCs) also caused neuronal differentiation, similar to cancer cells. Particularly, EZH2 interacts with and required for the stability of LSD1, HDAC1, DNMT1, β-CATENIN, or SMAD2/4, via recruitment of deubiquitinase USP7. Reduced EZH2 leads to enhanced ubiquitination and degradation of these proteins, and decreased binding of LSD1, HDAC1, and DNMT1 to neuronal gene promoters, and lessened Wnt and TGFβ target gene activation. Hence, EZH2 sustains a series of proteins that promote tumorigenesis, in addition to its original function of histone methylation. Considering together with other studies, we conclude that these chromatin modification factors function in the same way in cancer cells as in neural progenitor/stem cells. The similarity between cancer cells and neural progenitor/stem cells provides an insight into the essence and unified framework for cancer initiation and progression, and are suggestive for novel strategies of cancer therapy.

Similarity in gene-regulatory networks suggests that cancer cells share characteristics of embryonic neural cells

Cancer cells are immature cells resulting from cellular reprogramming by gene misregulation, and redifferentiation is expected to reduce malignancy. It is unclear, however, whether cancer cells can undergo terminal differentiation. Here, we show that inhibition of the epigenetic modification enzyme enhancer of zeste homolog 2 (EZH2), histone deacetylases 1 and 3 (HDAC1 and -3), lysine demethylase 1A (LSD1), or DNA methyltransferase 1 (DNMT1), which all promote cancer development and progression, leads to postmitotic neuron-like differentiation with loss of malignant features in distinct solid cancer cell lines. The regulatory effect of these enzymes in neuronal differentiation resided in their intrinsic activity in embryonic neural precursor/progenitor cells. We further found that a major part of pan-cancer-promoting genes and the signal transducers of the pan-cancer-promoting signaling pathways, including the epithelial-to-mesenchymal transition (EMT) mesenchymal marker genes, display neural specific expression during embryonic neurulation. In contrast, many tumor suppressor genes, including the EMT epithelial marker gene that encodes cadherin 1 (CDH1), exhibited non-neural or no expression. This correlation indicated that cancer cells and embryonic neural cells share a regulatory network, mediating both tumorigenesis and neural development. This observed similarity in regulatory mechanisms suggests that cancer cells might share characteristics of embryonic neural cells.

JmjC Domain-containing Protein 6 (Jmjd6) Derepresses the Transcriptional Repressor Transcription Factor 7-like 1 (Tcf7l1) and Is Required for Body Axis Patterning during Xenopus Embryogenesis

Tcf7l1 (also known as Tcf3) is a bimodal transcription factor that plays essential roles in embryogenesis and embryonic and adult stem cells. On one hand, Tcf7l1 works as transcriptional repressor via the recruitment of Groucho-related transcriptional corepressors to repress the transcription of Wnt target genes, and, on the other hand, it activates Wnt target genes when Wnt-activated β-catenin interacts with it. However, how its activity is modulated is not well understood. Here we demonstrate that a JmjC-domain containing protein, Jmjd6, interacts with Tcf7l and derepresses Tcf7l. We show that Jmjd6 binds to a region of Tcf7l1 that is also responsible for Groucho interaction, therefore making it possible that Jmjd6 binding displaces the Groucho transcriptional corepressor from Tcf7l1. Moreover, we show that Jmjd6 antagonizes the repression effect of Tcf7l1 on target gene transcription and is able to enhance β-catenin-induced gene activation and that, vice versa, inhibition of Jmjd6 activity compromises gene activation in both cells and Xenopus early embryos. We also show that jmjd6 is both maternally and zygotically transcribed during Xenopus embryogenesis. Loss of Jmjd6 function causes defects in anterioposterior body axis formation and down-regulation of genes that are involved in anterioposterior axis patterning. The results elucidate a novel mechanism underlying the regulation of Tcf7l1 activity and the regulation of embryonic body axis formation.

Proteomic analysis of tilapia Oreochromis niloticus Streptococcus agalactiae strains with different genotypes and serotypes

Nine tilapia Oreochromis niloticus group B streptococcus (GBS) strains differing in serotype and genotype were selected and paired. Two-dimensional difference gel electrophoresis (2D DIGE) and matrix-assisted laser-desorption ionization time-of-flight-mass spectrometry (MALDI-TOF-MS) were used to analyse the protein profiles of the strain pairs. Forty-three proteins corresponding to 66 spots were identified, of which 35 proteins were found in the seven selected strain pairs that represented pairs differing in genotype and serotype. Among the 35 proteins, numbers of differentially expressed proteins in strains of different serotypes were greater than found in strains of different genotypes, suggesting that serotype plays a more essential role than genotype in the differential protein expression among GBS strains. No distinct pattern was found with respect to genotype and the protein expression profile of GBS strains. Several proteins were identified as surface-associated cytoplasmic proteins that possessed the typical immunity-eliciting characteristics of surface proteins. The identified proteins were found to be involved in 16 biological processes and seven Kyoto encyclopaedia of genes and genomes (KEGG) pathways. The data, for the first time, identified differentially expressed proteins in O. niloticus GBS strains of different serotypes, which play a major role in immunogenicity of O. niloticus GBS than does genotype, offering further information for design of a vaccine against O. niloticus GBS.

The effects of a novel metabotropic glutamate receptor 5 antagonist (AZD2066) on transient lower oesophageal sphincter relaxations and reflux episodes in healthy volunteers

BACKGROUND

Selective metabotropic glutamate receptor 5 (mGluR5) antagonists inhibit transient lower oesophageal sphincter relaxations (TLESRs) in animals and acid reflux in humans.

AIM

To assess the effect of single doses of the mGluR5 antagonist AZD2066 on TLESRs and reflux in humans.

METHODS

Healthy male volunteers received AZD2066 13 mg and placebo (part A), or AZD2066 2 mg and AZD2066 6 mg and placebo (part B), in a randomised crossover study. Postprandial manometry/pH-impedance measurements were taken after each dose.

RESULTS

A total of 13 individuals completed part A of the study and 19 individuals completed part B. There was a significant reduction in the geometric mean number of TLESRs (27%; P = 0.02) and the geometric mean number of reflux episodes (51%; P = 0.01) in subjects receiving AZD2066 13 mg compared with placebo. Adverse events in participants receiving AZD2066 13 mg were mostly related to the nervous system [dizziness (3/13); disturbance in attention (3/13)]. Adverse events were reversible and of mild intensity. There were no serious adverse events. The effects of AZD2066 appeared dose-dependent, with smaller reductions in TLESRs and reflux episodes (relative to placebo) and fewer adverse events observed for AZD2066 2 mg and AZD2066 6 mg compared with AZD2066 13 mg.

CONCLUSION

The mGluR5-mediated inhibition of TLESRs may be a useful approach for inhibiting gastro-oesophageal reflux.

Randomised clinical trial: the effects of amitriptyline on drinking capacity and symptoms in patients with functional dyspepsia, a double-blind placebo-controlled study

BACKGROUND

Functional dyspepsia is one of the most prevalent (15-40%) functional gastrointestinal disorders. Antidepressants such as amitriptyline are often used in these patients, but clinical studies are currently lacking.

AIM

To evaluate the effect of 8 weeks of treatment with amitriptyline on drinking capacity, symptoms evoked by a standardised drink test (primary endpoint) and clinical symptoms (secondary endpoint).

METHODS

Patients meeting the Rome III criteria for functional dyspepsia (FD) were invited to participate in a double blind, randomised, placebo-controlled trial and were treated with either amitriptyline (12.5-50 mg) or placebo during 8 weeks. All included patients underwent a nutrient drink test before and after treatment. Drinking capacity and evoked symptoms were recorded. In addition, dyspeptic symptoms were weekly assessed using PAGI SYM (patient assessment of upper gastrointestinal symptom severity index) questionnaire.

RESULTS

Thirty-eight patients (amitriptyline n=18, placebo n=20; age 41±2year, 61% F) completed the study. The drinking capacity of liquid meal was not affected by either amitriptyline or placebo treatment. Postprandial symptoms were not significantly different between amitriptyline and placebo. During the entire treatment, total symptom score (0.47 points, P=0.02) and nausea (0.86 points, P=0.004) on PAGI SYM were significantly reduced by amitriptyline compared with placebo.

CONCLUSIONS

Amitriptyline did not affect drinking capacity and postprandial symptoms evoked by the drink test in FD patients. However, total clinical symptom score and nausea were reduced during 8 weeks of treatment. Our data suggest that amitriptyline particularly improves nausea in functional dyspepsia, but larger clinical trials are needed to further confirm our findings.

The GABA(B) receptor agonist AZD9343 inhibits transient lower oesophageal sphincter relaxations and acid reflux in healthy volunteers: a phase I study

BACKGROUND

Transient lower oesophageal sphincter relaxations (TLESRs) represent an interesting target for the treatment of gastro-oesophageal reflux. Baclofen reduces TLESRs and reflux episodes, but is not optimal for clinical application because of its central side effects. Therefore, new agents are required.

AIM

To study the effect of AZD9343, a new selective GABA(B) receptor agonist, in healthy volunteers.

METHODS

A total of 27 subjects participated in a placebo-controlled, randomized, two-centre phase I study. Subjects underwent oesophageal manometry and pH-metry for 3 h postprandially. Before meal ingestion, a single oral dose of placebo, 60 and 320 mg AZD9343 or 40 mg baclofen was given on four separate days.

RESULTS

Somnolence was reported after 320 mg AZD9343 and baclofen. Reversible short-lasting paraesthesia was reported after AZD9343. AZD9343 320 mg and baclofen significantly reduced the number of TLESRs with 32% and 40% respectively. Acid reflux was significantly decreased by AZD9343 and baclofen. Like baclofen, AZD9343 increased LES pressure before meal intake. AZD9343 320 mg and baclofen significantly reduced the swallowing rate.

CONCLUSIONS

Like baclofen, AZD9343 dose-dependently decreases the number of TLESRs and acid reflux episodes, increases LES pressure and reduces swallowing, extending the concept that GABA(B) agonists are potent reflux inhibitors. However, discovery of analogues with an improved side effect profile is warranted.

Effect of long-term treatment with octreotide on rectal sensitivity in patients with non-constipated irritable bowel syndrome

BACKGROUND

Acute administration of octreotide reduces visceral perception and therefore has been suggested as potential treatment for irritable bowel syndrome. Whether prolonged treatment with octreotide also reduces visceral sensitivity and improves gastrointestinal symptoms remains, however, unknown.

AIM

To investigate the effect of a slow release preparation of octreotide on rectal sensitivity and symptoms in irritable bowel syndrome patients.

METHODS

Forty-six non-constipated irritable bowel syndrome patients (52% female, 19-63 years) participated. Before and after 8 weeks of treatment with octreotide (Sandostatin LAR 20 mg i.m.) or placebo, patients underwent a barostat study to assess the rectal sensitivity. During a 2-week run-in period and treatment, abdominal pain, defecation frequency, consistency and symptom relief were scored weekly.

RESULTS

Octreotide, but not placebo, significantly increased the threshold for first sensation. Thresholds for urge to defecate and discomfort/pain and rectal compliance were not altered by either treatment. Octreotide improved stool consistency compared with placebo (loose stools after eight weeks: octreotide: 52%, placebo: 81%, P < 0.05). In contrast, abdominal pain and defecation frequency were not affected.

CONCLUSIONS

Although the threshold of first rectal sensation increased and stool consistency improved, long-term treatment with octreotide, at least at the current dose used, has no visceral analgesic effect and fails to improve irritable bowel syndrome symptoms.

Possible role of nitric oxide in visceral hypersensitivity in patients with irritable bowel syndrome

Visceral hypersensitivity is a consistent finding in a considerable proportion of patients with irritable bowel syndrome (IBS), and may provide a physiological basis for the development of IBS symptoms. In this study, we aimed to confirm the hypothesis that nitric oxide (NO) is involved in maintaining visceral hypersensitivity in IBS. Ten healthy volunteers (HV) and 12 IBS patients with documented hypersensitivity to rectal distension underwent a rectal barostat study. The effect of placebo and the specific NO synthase inhibitor NG -monomethyl-L-arginine (L-NMMA) on resting volume, rectal sensitivity to distension and rectal compliance was evaluated in a double-blind, randomized, cross-over fashion. NG -monomethyl-L-arginine did not alter resting volumes in HV or IBS patients. In HV, l-NMMA did not alter rectal sensory thresholds compared to placebo (45 +/- 3 and 46 +/- 3 mmHg, respectively). In contrast, L-NMMA significantly increased the threshold for discomfort/pain in IBS patients (placebo: 18 +/- 2, l-NMMA: 21 +/- 3 mmHg, P < 0.05). Rectal compliance was not affected by L-NMMA. Although NO does not seem to play a major role in normal rectal sensation or tone, we provide evidence that NO may be involved in the pathophysiology of visceral hypersensitivity in IBS.

Reproducibility of meal-induced transient lower oesophageal sphincter relaxations in patients with gastro-oesophageal reflux disease

AIM

To calculate the number of subjects required in trials investigating drugs reducing the number of transient lower oesophageal sphincter relaxations (TLOSRs), the inter- and intra-individual variability of TLOSRs were determined, using meal ingestion as a trigger of TLOSRs and reflux.

METHODS

A total of 23 gastro-oesophageal reflux disease (GORD) patients with no to grade B oesophagitis and a hiatal hernia < or =3 cm underwent oesophageal manometry and pHmetry 1 h before and 3 h after ingestion of a solid meal on two separate days approximately 4 weeks apart. Reflux episodes and the underlying mechanisms and the number of TLOSRs were evaluated.

RESULTS

The number of TLOSRs, reflux episodes and % time with pH < 4 after meal ingestion did not differ significantly between the two sessions. The intra-individual variation of TLOSRs in the 3 h postprandial period (24.4) was smaller compared with the inter-individual variation (47.5). Transient lower oesophageal sphincter relaxations were the predominant cause of reflux accounting for 61 +/- 7 and 70 +/- 5% of the reflux episodes in visits 1 and 2, respectively.

CONCLUSIONS

These data for the first time provide information on the variability of TLOSRs and reflux evoked by meal ingestion, which is of crucial importance for the design and power calculations of future clinical studies evaluating the efficacy of new drugs targeting TLOSRs.

Effect of the low-affinity, noncompetitive N-methyl-d-aspartate receptor antagonist dextromethorphan on visceral perception in healthy volunteers

BACKGROUND

The use of N-methyl-d-aspartate (NMDA) receptor antagonists may hold promise for the treatment of pain of visceral origin, in particular in conditions characterized by visceral hypersensitivity.

AIM

To study the effect of dextromethorphan, a low affinity, non-competitive NMDA receptor antagonist, on visceral perception in healthy volunteers.

METHODS

Nine healthy volunteers (5 female, median age 22 years) underwent a gastric barostat study after oral administration of placebo, dextromethorphan 10 mg or dextromethorphan 30 mg, on three separate days in a double-blind, randomised order. Sensations induced by step-wise isobaric gastric distension (2 mmHg/2 min) were studied during fasting and 30 min after a meal. In addition, proximal gastric tone was measured during fasting and postprandially.

RESULTS

Compared to placebo, dextromethorphan 30 mg significantly increased the distension-evoked sensation scores for nausea (P=0.004) and satiation (P=0.004) during fasting; and for bloating (P= 0.001), nausea (P=0.000) and satiation (P=0.01) 30 min postprandially. Dextromethorphan did not alter pain scores, proximal gastric tone or gastric compliance.

CONCLUSIONS

Dextromethorphan increases the perception of non-painful sensations during gastric distension, without altering the perception of pain. Therefore, application of dextromethorphan as a visceral analgesic is questionable. Future studies with more specific NMDA receptor antagonist are warranted.

[A study of histopathology and cell proliferation in calcifying odontogenic cyst]

OBJECTIVE

To investigate the histopathologic and clinical characteristics and proliferative activities of calcifying odontogenic cyst (COC).

METHODS

25 cases of COC were reviewed. The expression of proliferating cell nuclear antigen (PCNA) was studied using avidin-biotin peroxidase method and the number of nuclear organizing regions was calculated by means of the argyrophil staining technique in these cases.

RESULTS

The cases were divided into 13 (52%) cysts and 12 (48%) neoplasms. Of the 12 neoplasms, 4 were odontogenic ghost cell carcinoma, with a PCNA labelling index (65.9% +/- 7.3%) significantly higher than that of benign neoplastic variant (45.8% +/- 11.5%, P < 0.05) and cystic variant (29.3% +/- 11.2%, P < 0.01). The AgNOR counts was higher in the carcinomatous than benign or cystic variant.

CONCLUSION

The lesions show considerable diversity in structure and behavior. It is therefore proposed that quantiation of staining for NOR-associated proteins and the PCNA labelling index are diagnostically useful in COC.