<i>atonal-</i> and <i>achaete-scute</i>-related genes in the annelid <i>Platynereis dumerilii</i>: insights into the evolution of neural basic-Helix-Loop-Helix genes

Background: Functional studies in model organisms, such as vertebrates and Drosophila, have shown that basic Helix-loop-Helix ( bHLH) proteins have important roles in different steps of neurogenesis, from the acquisition of neural fate to the differentiation into specific neural cell types. However, these studies highlighted many differences in the expression and function of orthologous bHLH proteins during neural development between vertebrates and Drosophila. To understand how the functions of neural bHLH genes have evolved among bilaterians, we have performed a detailed study of bHLH genes during nervous system development in the polychaete annelid, Platynereis dumerilii, an organism which is evolutionary distant from both Drosophila and vertebrates. Results: We have studied Platynereis orthologs of the most important vertebrate neural bHLH genes, i.e. achaete-scute, neurogenin, atonal, olig, and NeuroD genes, the latter two being genes absent of the Drosophila genome. We observed that all these genes have specific expression patterns during nervous system formation in Platynereis. Our data suggest that in Platynereis, like in vertebrates but unlike Drosophila, ( i) neurogenin is the main proneural gene for the formation of the trunk central nervous system, (ii) achaetescute and olig genes are involved in neural subtype specification in the central nervous system, in particular in the specification of the serotonergic phenotype. In addition, we found that the Platynereis NeuroD gene has a broad and early neuroectodermal expression, which is completely different from the neuronal expression of vertebrate NeuroD genes. Conclusion: Our analysis suggests that the Platynereis bHLH genes have both proneural and neuronal specification functions, in a way more akin to the vertebrate situation than to that of Drosophila. We conclude that these features are ancestral to bilaterians and have been conserved in the vertebrates and annelids lineages, but have diverged in the evolutionary lineage leading to Drosophila

Transcriptomic effects of adenosine 2A receptor deletion in healthy and endotoxemic murine myocardium

Influences of adenosine 2A receptor (A2AR) activity on the cardiac transcriptome and genesis of endotoxemic myocarditis are unclear. We applied transcriptomic profiling (39 K Affymetrix arrays) to identify A2AR-sensitive molecules, revealed by receptor knockout (KO), in healthy and endotoxemic hearts. Baseline cardiac function was unaltered and only 37 A2AR-sensitive genes modified by A2AR KO (≥1.2-fold change, \u3c5 \u3e% FDR); the five most induced are Mtr, Ppbp, Chac1, Ctsk and Cnpy2 and the five most repressed are Hp, Yipf4, Acta1, Cidec and Map3k2. Few canonical paths were impacted, with altered Gnb1, Prkar2b, Pde3b and Map3k2 (among others) implicating modified G protein/cAMP/PKA and cGMP/NOS signalling. Lipopolysaccharide (LPS; 20 mg/kg) challenge for 24 h modified \u3e4100 transcripts in wild-type (WT) myocardium (≥1.5-fold change, FDR \u3c 1 %); the most induced are Lcn2 (+590); Saa3 (+516); Serpina3n (+122); Cxcl9 (+101) and Cxcl1 (+89) and the most repressed are Car3 (−38); Adipoq (−17); Atgrl1/Aplnr (−14); H19 (−11) and Itga8 (−8). Canonical responses centred on inflammation, immunity, cell death and remodelling, with pronounced amplification of toll-like receptor (TLR) and underlying JAK-STAT, NFκB and MAPK pathways, and a ‘cardio-depressant’ profile encompassing suppressed ß-adrenergic, PKA and Ca2+ signalling, electromechanical and mitochondrial function (and major shifts in transcripts impacting function/injury including Lcn2, S100a8/S100a9, Icam1/Vcam and Nox2 induction, and Adipoq, Igf1 and Aplnr repression). Endotoxemic responses were selectively modified by A2AR KO, supporting inflammatory suppression via A2AR sensitive shifts in regulators of NFκB and JAK-STAT signalling (IκBζ, IκBα, STAT1, CDKN1a and RRAS2) without impacting the cardio-depressant gene profile. Data indicate A2ARs exert minor effects in un-stressed myocardium and selectively suppress NFκB and JAK-STAT signalling and cardiac injury without influencing cardiac depression in endotoxemia

Gs-Coupled Adenosine Receptors Differentially Limit Antigen-Induced Mast Cell Activation

Mast cell activation results in the immediate release of proinflammatory mediators prestored in cytoplasmic granules, as well as initiation of lipid mediator production and cytokine synthesis by these resident tissue leukocytes. Allergen-induced mast cell activation is central to the pathogenesis of asthma and other allergic diseases. Presently, most pharmacological agents for the treatment of allergic disease target receptors for inflammatory mediators. Many of these mediators, such as histamine, are released by mast cells. Targeting pathways that limit antigen-induced mast cell activation may have greater therapeutic efficacy by inhibiting the synthesis and release of many proinflammatory mediators produced in the mast cell. In vitro studies using cultured human and mouse mast cells, and studies of mice lacking A2B receptors, suggest that adenosine receptors, specifically the Gs-coupled A2A and A2B receptors, might provide such a target. Here, using a panel of mice lacking various combinations of adenosine receptors, and mast cells derived from these animals, we show that adenosine receptor agonists provide an effective means of inhibition of mast cell degranulation and induction of cytokine production both in vitro and in vivo. We identify A2B as the primary receptor limiting mast cell degranulation, whereas the combined activity of A2A and A2B is required for the inhibition of cytokine synthesis

A2A adenosine receptor deletion is protective in a mouse model of Tauopathy

© 2016 Macmillan Publishers Limited All rights reserved. This work is licensed under a Creative Commons Attribution- NonCommercial-NoDerivs 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http:// creativecommons.org/licenses/by-nc-nd/4.0/Consumption of caffeine, a non-selective adenosine A2A receptor (A2AR) antagonist, reduces the risk of developing Alzheimer's disease (AD) in humans and mitigates both amyloid and Tau burden in transgenic mouse models. However, the impact of selective A2AR blockade on the progressive development of AD-related lesions and associated memory impairments has not been investigated. In the present study, we removed the gene encoding A2AR from THY-Tau22 mice and analysed the subsequent effects on both pathological (Tau phosphorylation and aggregation, neuro-inflammation) and functional impairments (spatial learning and memory, hippocampal plasticity, neurotransmitter profile). We found that deleting A2ARs protect from Tau pathology-induced deficits in terms of spatial memory and hippocampal long-term depression. These effects were concomitant with a normalization of the hippocampal glutamate/gamma-amino butyric acid ratio, together with a global reduction in neuro-inflammatory markers and a decrease in Tau hyperphosphorylation. Additionally, oral therapy using a specific A2AR antagonist (MSX-3) significantly improved memory and reduced Tau hyperphosphorylation in THY-Tau22 mice. By showing that A2AR genetic or pharmacological blockade improves the pathological phenotype in a Tau transgenic mouse model, the present data highlight A2A receptors as important molecular targets to consider against AD and Tauopathies.This work was supported by grants from France Alzheimer (to DB) and LECMA/Alzheimer Forschung Initiative (to DB and CEM). DB and LVL got a Égide/Pessoa program EU exchange grant. Our laboratory is also supported by the LabEx (excellence laboratory) DISTALZ (Development of Innovative Strategies for a Transdisciplinary approach to ALZheimer’s disease), Inserm, CNRS, Université Lille 2, Lille Métropole Communauté Urbaine, Région Nord/Pas-de-Calais, FEDER, DN2M, ANR (ADONTAGE and ADORATAU, to DB) and FUI MEDIALZ. We thank the animal facility of IMPRT-IFR114 and M Besegher, I Brion, D Cappe, R Dehaynin, J Devassine, Y Lepage, C Meunier and D Taillieu for transgenic mouse production and animal care, as well as M Basquin, D Demeyer, S Eddarkaoui, H Obriot and M Schneider for support. CL holds a doctoral grant from Lille 2 University, and SB from Région Nord Pas de Calais and CHRU de Lille. VF holds a grant from Région Nord-Pas-de-Calais and Inserm. EF holds a post-doctoral grant from Région Nord-Pas-de-Calais (DN2M). LVL is an Investigator FCT (Fundação para a Ciência e Tecnologia, Portugal).info:eu-repo/semantics/publishedVersio

Gs-Coupled Adenosine Receptors Differentially Limit Antigen-Induced Mast Cell Activation

Mast cell activation results in the immediate release of proinflammatory mediators prestored in cytoplasmic granules, as well as initiation of lipid mediator production and cytokine synthesis by these resident tissue leukocytes. Allergen-induced mast cell activation is central to the pathogenesis of asthma and other allergic diseases. Presently, most pharmacological agents for the treatment of allergic disease target receptors for inflammatory mediators. Many of these mediators, such as histamine, are released by mast cells. Targeting pathways that limit antigen-induced mast cell activation may have greater therapeutic efficacy by inhibiting the synthesis and release of many proinflammatory mediators produced in the mast cell. In vitro studies using cultured human and mouse mast cells, and studies of mice lacking A2B receptors, suggest that adenosine receptors, specifically the Gs-coupled A2A and A2B receptors, might provide such a target. Here, using a panel of mice lacking various combinations of adenosine receptors, and mast cells derived from these animals, we show that adenosine receptor agonists provide an effective means of inhibition of mast cell degranulation and induction of cytokine production both in vitro and in vivo. We identify A2B as the primary receptor limiting mast cell degranulation, whereas the combined activity of A2A and A2B is required for the inhibition of cytokine synthesis

Long-term (trophic) purinergic signalling: purinoceptors control cell proliferation, differentiation and death

The purinergic signalling system, which uses purines and pyrimidines as chemical transmitters, and purinoceptors as effectors, is deeply rooted in evolution and development and is a pivotal factor in cell communication. The ATP and its derivatives function as a 'danger signal' in the most primitive forms of life. Purinoceptors are extraordinarily widely distributed in all cell types and tissues and they are involved in the regulation of an even more extraordinary number of biological processes. In addition to fast purinergic signalling in neurotransmission, neuromodulation and secretion, there is long-term (trophic) purinergic signalling involving cell proliferation, differentiation, motility and death in the development and regeneration of most systems of the body. In this article, we focus on the latter in the immune/defence system, in stratified epithelia in visceral organs and skin, embryological development, bone formation and resorption, as well as in cancer. Cell Death and Disease (2010) 1, e9; doi:10.1038/cddis.2009.11; published online 14 January 201

A Two-Hybrid Assay to Study Protein Interactions within the Secretory Pathway

Interactions of transcriptional activators are difficult to study using transcription-based two-hybrid assays due to potent activation resulting in false positives. Here we report the development of the Golgi two-hybrid (G2H), a method that interrogates protein interactions within the Golgi, where transcriptional activators can be assayed with negligible background. The G2H relies on cell surface glycosylation to report extracellularly on protein-protein interactions occurring within the secretory pathway. In the G2H, protein pairs are fused to modular domains of the reporter glycosyltransferase, Och1p, and proper cell wall formation due to Och1p activity is observed only when a pair of proteins interacts. Cells containing interacting protein pairs are identified by selectable phenotypes associated with Och1p activity and proper cell wall formation: cells that have interacting proteins grow under selective conditions and display weak wheat germ agglutinin (WGA) binding by flow cytometry, whereas cells that lack interacting proteins display stunted growth and strong WGA binding. Using this assay, we detected the interaction between transcription factor MyoD and its binding partner Id2. Interfering mutations along the MyoD:Id2 interaction interface ablated signal in the G2H assay. Furthermore, we used the G2H to detect interactions of the activation domain of Gal4p with a variety of binding partners. Finally, selective conditions were used to enrich for cells encoding interacting partners. The G2H detects protein-protein interactions that cannot be identified via traditional two-hybrid methods and should be broadly useful for probing previously inaccessible subsets of the interactome, including transcriptional activators and proteins that traffic through the secretory pathway