Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : International audience
Necroptosis is a programmed cell death pathway that has been shown to be of central pathophysiological relevance in multiple disorders (hepatitis, brain and cardiac ischemia, pancreatitis, viral infection and inflammatory diseases). Necroptosis is driven by two serine threonine kinases, RIPK1 (Receptor Interacting Protein Kinase 1) and RIPK3, and a pseudo-kinase MLKL (Mixed Lineage Kinase domain-Like) associated in a multi-protein complex called necrosome. In order to find new inhibitors for use in human therapy, a chemical library containing highly diverse chemical structures was screened using a cell-based assay. The compound 6E11, a natural product derivative, was characterized as a positive hit. Interestingly, this flavanone compound: inhibits necroptosis induced by death receptors ligands TNF-α (Tumor Necrosis Factor) or TRAIL (TNF-Related Apoptosis-Inducing Ligand); is an extremely selective inhibitor, among kinases, of human RIPK1 enzymatic activity with a nM Kd; has a non-ATP competitive mode of action and a novel putative binding site; is weakly cytotoxic towards human primary blood leukocytes or retinal pigment epithelial cells at effective concentrations; protects human aortic endothelial cells (HAEC) from cold hypoxia/reoxygenation injury more effectively than necrostatin-1 (Nec-1) and Nec-1s. Altogether, these data demonstrate that 6E11 is a novel potent small molecular inhibitor of RIPK1-driven necroptosis.
ISSN: 2045-2322

hal-01616456
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01616456
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01616456/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01616456/file/s41598-017-12788-4.pdf
DOI : 10.1038/s41598-017-12788-4

Éditeur(s) : HAL CCSD Society for the Study of Reproduction
Résumé : International audience
Spermmotility notably depends on the structural integrity of the flagellum and the regulation ofmicrotubule dynamics. Although researchers have started to use " omics" techniques to characterize the human sperm's molecular landscape, the constituents responsible for the assembly, organization, and dynamics of the flagellum microtubule have yet to be fully defined. In this study, we defined a core set of 116 gene products associated with the human sperm microtubulome (including products potentially involved in abnormal ciliary phenotypes and male infertility disorders). To this end, we designed and applied an integrated genomics workflow and combined relevant proteomics, transcriptomics, and interactomics datasets to reconstruct a dynamic interactome map. By further integrating phenotypic information, we defined a disease-interaction network; this enabled us to highlight a number of novel factors potentially associated with altered sperm motility and male fertility. Lastly, we experimentally validated the expression pattern of two candidate genes (CUL3 and DCDC2C) that had never previously been associated with male germline differentiation. Our analysis suggested that CUL3 and DCDC2C's products have important roles in the sperm flagellum. Taken as a whole, our results demonstrate that an integrated genomics strategy can highlight relevant molecular factors in specific sperm components. This approach could be easily extended by including other " omics" data (from asthenozoospermic men, for example) and identifying other critical proteins from the human sperm microtubulome. Summary Sentence Although researchers have started to use "omics" techniques to characterize the human sperm's molecular landscape, the constituents responsible for the assembly, organization, and dynamics of the flagellum microtubule have yet to be fully defined.
ISSN: 0006-3363

hal-01515563
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01515563
DOI : 10.1095/biolreprod.116.143479
PUBMED : 28395323

Éditeur(s) : HAL CCSD
Résumé : Anti-Müllerian hormone (AMH) is a member of the TGF-ß superfamily. AMH is well known for its role in Müllerian duct regression in male fetuses. Postnatally, AMH is secreted by granulosa cells (GCs) of small growing follicles (preantral and small antral). However, despite the increasing interest of ovarian AMH in clinics, little is known on its mechanism of action and its role in female reproductive tract. My PhD project focuses on the identification of AMH function in the female reproductive tract.AMH signals through a type II transmembrane serine/threonine kinase receptor (AMHR-II) which forms a complex with a type I serine/threonine kinase receptor (ActR-IA, BMPR-IA, BMPR-IB). The type II receptor phosphorylates serine and threonine residues of type I receptor. Once activated, the type I receptor phosphorylates the receptor-regulated Smads (R-Smad1/5/8) which interact with a common partner Smad4. The Smad complex accumulates into the nucleus and regulates target gene expression. This canonical signalling pathway is regulated at different levels, in particular by co-receptors which amplify or antagonize TGF-ß family members action. The type I receptors and R-Smads involved in AMH effects on post-natal GCs remain unknown. In addition, to date, no co-receptor has been found for AMH. To define the involvement of the different type I receptors, we used siRNA technology to inactivate Acvr1, Bmpr1a and Bmpr1b in GC. In parallele, we analysed GC extracted from conditional mutant mice for Acvr1 and Bmpr1a. We found that BMPR-IA is the most important type I receptor for AMH to transduce its signal in GC. A Smad-Gal4/UAS-luciferase reporter gene technology allowed us to show that Smad1 and 5 are involved in AMH signaling pathway. Recently, new BMPs coreceptors were found, RGMs for Repulsive Guidance Molecules. There are three RGMs : RGMa, b and c. Because AMH shares with BMPs its type I receptors and R-Smad proteins, we hypothesized that they also share the same co-receptors, the RGM. We showed that RGMb was the only one expressed in GC and after siRNA transfection we demonstrated that this coreceptor is not essential for AMH to transduce its signal.To date, only few AMH target genes have been identified. Aromatase (Cyp19a1) and LH receptor (Lhcgr) are down-regulated by AMH in rat and porcine GCs. We used micro-array technology (Affymetrix) by comparing Wt and knockout immature ovaries to find new AMH target genes. This experiment evidenced that Ovgp1 and Kcnj2 are two new potential AMH target genes in the ovary.The last part of my project was to define a potential role of AMH in murine uterus. Only one study showed that AMHR-II is expressed in the mouse myometrium. We showed that Amh gene is slightly expressed in uterus but the results are not confirmed at the protein level. Using PCR-array, we found a lot of differentially expressed genes between Wt and Amh KO uterus. Therefore, AMH could regulate uterine function through the modulation of different genes located in the myometrium.
L’hormone anti-Müllerienne (AMH) est un membre de la famille TGF-β impliquée dans la différenciation du tractus reproductif mâle. Elle est aussi exprimée par les cellules de la granulosa de l’ovaire adulte. Cependant, son rôle physiologique chez la femelle n’a pas encore été entièrement établi. Mon projet de thèse a pour objectif d’élucider le(s) rôle(s) de l’AMH dans le tractus reproductif femelle. L’AMH transduit ses effets par l’intermédiaire de deux récepteurs transmembranaires sérine/thréonine kinase : un récepteur de type II qui lui est spécifique (AMHR-II) et un récepteur de type I (ActR-IA, BMPR-IA, BMPR-IB) qu’elle partage avec les BMPs. Après fixation de l’hormone sur le récepteur de type II, celui-ci recrute et phosphoryle le récepteur de type I. Ce dernier phosphoryle à son tour les Smads spécifiques (Smad1, 5 et 8) qui s’associent à la Smad commune, Smad4. L’ensemble transloque dans le noyau et en association avec des facteurs de transcription régule les gènes cibles de l’hormone. L'utilisation de souris KO conditionnelles pour les récepteurs Acvr1 et Bmpr1a et d'une technique de siRNA dirigés contre chacun des trois récepteurs de type I a permis de mettre en évidence que le récepteur BMPR-IA est un acteur essentiel de la voie de signalisation de l'AMH dans les cellules de la granulosa. Pour déterminer la ou les Smad(s) impliquées, une technique de gènes rapporteurs, Smad-Gal4/UAS-luciférase, a été utilisée. Nous avons pu montrer que les Smad1 et 5 sont importantes pour la transduction du signal de l'AMH dans les cellules de la granulosa. Récemment des corécepteurs aux BMPs, les Repulsive Guidance Molecule (RGMs), ont été mis en évidence. L’AMH partageant sa voie de signalisation avec les BMPs, nous avons cherché à déterminer si ces corécepteurs pouvaient également intervenir dans la voie de signalisation de l’AMH. Il existe 3 types de RGMs: RGMa, RGMb et RGMc. Nous avons montré en q-PCR que seul RGMb est exprimé dans les cellules de la granulosa alors que les 3 RGMs sont exprimés dans l’ovaire. L'utilisation de siRNA dirigés contre RGMb a permis de montrer que ce récepteur n'est pas nécessaire à la transduction du signal de l'AMH. Actuellement, seuls deux gènes cibles de l’AMH sont connus dans les cellules de la granulosa : l’aromatase et le récepteur LH. Nous avons réalisé des analyses de puces à ADN (ou micro-array) pour décrire de nouveaux gènes cibles de l'AMH. L'analyse des puces a permis de décrire de nouveaux gènes régulés par cette hormone tels qu’Ovgp1 ou Kcnj2. La dernière partie de mon projet visait à déterminer un rôle potentiel de l'AMH dans l'utérus. En effet, le récepteur de cette hormone est exprimé dans le myomètre utérin de souris permettant de supposer qu’elle peut agir sur cet organe. Nous avons pu mettre en évidence une expression faible du gène de l’Amh dans l’utérus. En revanche, l’expression et la localisation de la protéine restent encore à définir. Une expérience de PCR-array a permis de montrer que de nombreux gènes sont différentiellement exprimés entre l’utérus Wt et l’utérus KO Amh. Ceci indique que l’AMH jouerait un rôle sur la régulation de la fonction utérine qu’elle soit exprimée ou non dans cet organe.
https://tel.archives-ouvertes.fr/tel-00989662

Droits : info:eu-repo/semantics/OpenAccess
NNT : 2014PA11T014
tel-00989662
https://tel.archives-ouvertes.fr/tel-00989662
https://tel.archives-ouvertes.fr/tel-00989662/document
https://tel.archives-ouvertes.fr/tel-00989662/file/VA_SEDES_LAURIANE_03042014.pdf

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Tuftelin (TUFT1) is an acidic, phosphorylated glycoprotein, initially discovered in developing enamel matrix. TUFT1 is expressed in many mineralized and non-mineralized tissues. We performed an evolutionary analysis of 82 mammalian TUFT1 sequences to identify residues and motifs that were conserved during 220 million years (Ma) of evolution. We showed that 168 residues (out of the 390 residues composing the human TUFT1 sequence) are under purifying selection. Our analyses identified several, new, putatively functional domains and confirmed previously described functional domains, such as the TIP39 interaction domain, which correlates with nuclear localization of the TUFT1 protein, that was demonstrated in several tissues. We also identified several sites under positive selection, which could indicate evolutionary changes possibly related to the functional diversification of TUFT1 during evolution in some lineages. We discovered that TUFT1 and MYZAP (myocardial zonula adherens protein) share a common ancestor that was duplicated circa 500 million years ago. Taken together, these findings expand our knowledge of TUFT1 evolution and provide new information that will be useful for further investigation of TUFT1 functions.
ISSN: 0022-2844

hal-01516886
http://hal.upmc.fr/hal-01516886
http://hal.upmc.fr/hal-01516886/document
http://hal.upmc.fr/hal-01516886/file/Delgado_2017_Evolutionary.pdf
DOI : 10.1007/s00239-017-9789-5

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
The symbiotic interaction between cnidarians, such as corals and sea anemones, and the unicellular algae Symbiodinium is regulated by yet poorly understood cellular mechanisms, despite the ecological importance of coral reefs. These mechanisms, including host-symbiont recognition and metabolic exchange, control symbiosis stability under normal conditions, but also lead to symbiosis breakdown (bleaching) during stress. This study describes the repertoire of the sterol-trafficking proteins Niemann-Pick type C (NPC1 and NPC2) in the symbiotic sea anemone Anemonia viridis. We found one NPC1 gene in contrast to the two genes (NPC1 and NPC1L1) present in vertebrate genomes. While only one NPC2 gene is present in many metazoans, this gene has been duplicated in cnidarians, and we detected four NPC2 genes in A. viridis. However, only one gene (AvNPC2-d) was upregulated in symbiotic relative to aposymbiotic sea anemones and displayed higher expression in the gastrodermis (symbiont-containing tissue) than in the epidermis. We performed immunolabelling experiments on tentacle cross sections and demonstrated that the AvNPC2-d protein was closely associated with symbiosomes. In addition, AvNPC1 and AvNPC2-d gene expression was strongly downregulated during stress. These data suggest that AvNPC2-d is involved in both the stability and dysfunction of cnidarian-dinoflagellate symbioses.
ISSN: 0962-1083

hal-01546166
https://hal.archives-ouvertes.fr/hal-01546166
DOI : 10.1111/mec.12876

Éditeur(s) : HAL CCSD American Society for Cell Biology
Résumé : International audience
Based on its shedding and binding activities, the disintegrin and metalloprotease 12 (ADAM12) has been implicated in cell signaling. Here we investigate the intracellular protein interaction network of the transmembrane ADAM12L variant using an integrative approach. We identify the integrin-linked kinase (ILK) as a new partner for ADAM12L cellular functions. We demonstrate that ADAM12L coimmunoprecipitates with ILK in cells and that its cytoplasmic tail is required for this interaction. In human cultured hepatic stellate cells (HSCs), which express high levels of endogenous ADAM12L and ILK, the two proteins are redistributed to focal adhesions upon stimulation of a β1 integrin-dependent pathway. We show that down-regulation of ADAM12L in HSCs leads to cytoskeletal disorganization and loss of adhesion. Conversely, up-regulation of ADAM12L induces the Akt Ser-473 phosphorylation-dependent survival pathway via stimulation of β1 integrins and activation of phosphoinositide 3-kinase (PI3K). Depletion of ILK inhibits this effect, which is independent of ADAM12L proteolytic activity and involves its cytoplasmic domain. We further demonstrate that overexpression of ADAM12L promotes kinase activity from ILK immunoprecipitates. Our data suggest a new role for ADAM12L in mediating the functional association of ILK with β1 integrin to regulate cell adhesion/survival through a PI3K/Akt signaling pathway.
ISSN: 1059-1524

Droits : info:eu-repo/semantics/OpenAccess
inserm-00717429
http://www.hal.inserm.fr/inserm-00717429
http://www.hal.inserm.fr/inserm-00717429/document
http://www.hal.inserm.fr/inserm-00717429/file/MBoC_E11-11-0918R-A_LEYME_ET_AL.pdf
PUBMED : 22767580

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Background & Aims: The severity of liver diseases is exacerbated by the death of hepatocytes, which can be induced by the sensing of pathogen associated molecular patterns (PAMPs) derived from the gut microbiota. The molecular mechanisms regulating these cell death pathways are poorly documented. In this study, we investigated the role of the receptor interacting protein kinase 1 (RIPK1), a protein known to regulate cell fate decisions, in the death of hepatocytes using two in vivo models of PAMP-induced hepatitis. Methods: Hepatitis was induced in mice by independent injections of two different bacterial PAMPs: lipopolysaccharide (LPS) and unmethylated CpG oligodeoxynucleotide (CpG-DNA) motifs. The role of RIPK1 was evaluated by using mice specifically lacking RIPK1 in liver parenchymal cells (Ripk1(LPC-KO)). Administration of liposome-encapsulated clodronate served to investigate the role of Kupffer cells in the establishment of the disease. Etanercept, a tumor necrosis factor (TNF)-decoy receptor, was used to study the contribution of TNF-alpha during LPS-mediated liver injury. Results: Whereas RIPK1 deficiency in liver parenchymal cells did not trigger basal hepatolysis, it greatly sensitized hepatocytes to apoptosis and liver damage following a single injection of LPS or CpG-DNA. Importantly, hepatocyte death was prevented by previous macrophage depletion or by TNF inhibition. Conclusions: Our data highlight the pivotal function of RIPK1 in maintaining liver homeostasis in conditions of macrophage-induced TNF burst in response to PAMPs sensing. Lay summary: Excessive death of hepatocytes is a characteristic of liver injury. A new programmed cell death pathway has been described involving upstream death ligands such as TNF and downstream kinases such as RIPK1. Here, we show that in the presence of LPS liver induced hepatic injury was due to secretion of TNF by liver macrophages, and that RIPK1 acts as a powerful protector of hepatocyte death. This newly identified pathway in the liver may be helpful in the management of patients to predict their risk of developing acute liver failure. (C) 2017 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.
ISSN: 0168-8278

hal-01532060
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01532060
DOI : 10.1016/j.jhep.2017.01.005
PUBMED : 28088582

Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : International audience
CYLD is a tumour suppressor gene mutated in familial cylindromatosis, a genetic disorder leading to the development of skin appendage tumours. It encodes a deubiquitinating enzyme that removes Lys63- or linear-linked ubiquitin chains. CYLD was shown to regulate cell proliferation, cell survival and inflammatory responses, through various signalling pathways. Here we show that CYLD localizes at centrosomes and basal bodies via interaction with the centrosomal protein CAP350 and demonstrate that CYLD must be both at the centrosome and catalytically active to promote ciliogenesis independently of NF-κB. In transgenic mice engineered to mimic the smallest truncation found in cylindromatosis patients, CYLD interaction with CAP350 is lost disrupting CYLD centrosome localization, which results in cilia formation defects due to impairment of basal body migration and docking. These results point to an undiscovered regulation of ciliogenesis by Lys63 ubiquitination and provide new perspectives regarding CYLD function that should be considered in the context of cylindromatosis.
ISSN: 2041-1723

hal-01063915
https://hal.archives-ouvertes.fr/hal-01063915
DOI : 10.1038/ncomms5585
PUBMED : 25134987

Éditeur(s) : HAL CCSD American Society of Hematology
Résumé : International audience
Sickle cell disease is characterized by painful vaso-occlusive crises during which abnormal interactions between erythroid adhesion molecules and vessel-wall proteins are thought to play a critical role. Hydroxyurea, the only drug with proven benefit in sickle cell disease, diminishes these interactions, but its mechanism of action is not fully understood. We report that, under hydroxyurea, expression of the unique erythroid laminin receptor Lu/BCAM was increased, but red blood cell adhesion to laminin decreased. Because Lu/BCAM phosphorylation is known to activate cell adhesion to laminin, it was evaluated and found to be dramatically lower in hydroxyurea-treated patients. Analysis of the protein kinase A pathway showed decreased intracellular levels of the upstream effector cyclic adenosine monophosphate during hydroxyurea treatment. Using a cellular model expressing recombinant Lu/BCAM, we showed that hydroxyurea led to decreased intracellular cyclic adenosine monophosphate levels and diminished Lu/BCAM phosphorylation and cell adhesion. We provide evidence that hydroxyurea could reduce abnormal sickle red blood cell adhesion to the vascular wall by regulating the activation state of adhesion molecules independently of their expression level.
ISSN: 0006-4971

inserm-00821117
http://www.hal.inserm.fr/inserm-00821117
http://www.hal.inserm.fr/inserm-00821117/document
http://www.hal.inserm.fr/inserm-00821117/file/Bartolucci_Blood_2010.pdf
DOI : 10.1182/blood-2009-12-257444

Éditeur(s) : HAL CCSD
Résumé : International audience
Necroptosis is a regulated form of cell death involved in several disease models including in particular liver diseases. Receptor-interacting protein kinases, RIPK1 and RIPK3, are the main serine/threonine kinases driving this cell death pathway. We screened a noncommercial, kinase-focused chemical library which allowed us to identify Sibiriline as a new inhibitor of necroptosis induced by tumor necrosis factor (TNF) in Fas-associated protein with death domain (FADD)-deficient Jurkat cells. Moreover, Sib inhibits necroptotic cell death induced by various death ligands in human or mouse cells while not protecting from caspase-dependent apoptosis. By using competition binding assay and recombinant kinase assays, we demonstrated that Sib is a rather specific competitive RIPK1 inhibitor. Molecular docking analysis shows that Sib is trapped closed to human RIPK1 adenosine triphosphate-binding site in a relatively hydrophobic pocket locking RIPK1 in an inactive conformation. In agreement with its RIPK1 inhibitory property, Sib inhibits both TNF-induced RIPK1-dependent necroptosis and RIPK1-dependent apoptosis. Finally, Sib protects mice from concanavalin A-induced hepatitis. These results reveal the small-molecule Sib as a new RIPK1 inhibitor potentially of interest for the treatment of immune-dependent hepatitis. © 2017 Federation of European Biochemical Societies
ISSN: 1742464X

hal-01616420
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01616420
DOI : 10.1111/febs.14176
PUBMED : 28715128

Éditeur(s) : HAL CCSD
Résumé : International audience
Selective serotonin reuptake inhibitor medications (SSRIs) are the first lines of treatment for maternal affective disorders, and are prescribed to up to 10% of pregnant women. Concern has been raised about how perinatal exposure to these medications affect offspring neurobehavioral outcomes, particularly those related to social interactions, as recent research has reported conflicting results related to autism spectrum disorder (ASD) risk in children prenatally exposed to SSRIs. Therefore, the aim of this work was to investigate the effects of perinatal exposure to the SSRI fluoxetine on social play behaviors and the hypothalamic pituitary adrenal system, using a model of pre-gestational maternal stress. We also investigated synaptic proteins in the CA2, CA3, and dentate gyrus of the hippocampus, as well as number of immature neurons in the granule cell layer, as both measures of plasticity in the hippocampus have been linked to social behaviors. In pre-adolescent male and female Sprague-Dawley rat offspring, main findings show that perinatal fluoxetine prevents the negative effect of maternal stress on sibling play behavior. However, perinatal fluoxetine increased social aggressive play with a novel conspecific in both sexes and decreased time grooming a novel conspecific in males only. Perinatal fluoxetine also increased serum corticosteroid binding globulin levels, 5-HT levels in the hippocampus, and pre-synaptic density assessed via synaptophysin in the dentate gyrus. Social interaction was significantly correlated with changes in plasticity in the CA2 region of the hippocampus. Pre-gestational maternal stress exposure resulted in significantly decreased rates of hippocampal neurogenesis and synaptophysin density in the dentate gyrus of pre-adolescent males, but not females. Together, these results further characterize the role of perinatal SSRIs, maternal stress prior to conception, and sex/gender on developing social behaviors and related plasticity in the hippocampus of pre-adolescent offspring.
Psychoneuroendocrinology

hal-01579611
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01579611
DOI : 10.1016/j.psyneuen.2017.07.480
PUBMED : 28735226

Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : International audience
The shallow water bivalve Codakia orbicularis lives in symbiotic association with a sulfur-oxidizing bacterium in its gills. The endosymbiont fixes CO2 and thus generates organic carbon compounds, which support the host's growth. To investigate the uncultured symbiont's metabolism and symbiont-host interactions in detail we conducted a proteogenomic analysis of purified bacteria. Unexpectedly, our results reveal a hitherto completely unrecognized feature of the C. orbicularis symbiont's physiology: the symbiont's genome encodes all proteins necessary for biological nitrogen fixation (diazotrophy). Expression of the respective genes under standard ambient conditions was confirmed by proteomics. Nitrogenase activity in the symbiont was also verified by enzyme activity assays. Phylogenetic analysis of the bacterial nitrogenase reductase NifH revealed the symbiont's close relationship to free-living nitrogen-fixing Proteobacteria from the seagrass sediment. The C. orbicularis symbiont, here tentatively named `Candidatus Thiodiazotropha endolucinida', may thus not only sustain the bivalve's carbon demands. C. orbicularis may also benefit from a steady supply of fixed nitrogen from its symbiont-a scenario that is unprecedented in comparable chemoautotrophic symbioses.
ISSN: 2058-5276

hal-01545904
https://hal.archives-ouvertes.fr/hal-01545904
DOI : 10.1038/nmicrobiol.2016.193

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
Background: The Hippo pathway regulates growth rate and organ size in fly and mouse, notably through control of cell proliferation. Molecular interactions at the heart of this pathway are known to have originated in the unicellular ancestry of metazoans. They notably involve a cascade of phosphorylations triggered by the kinase Hippo, with sub‑ sequent nuclear to cytoplasmic shift of Yorkie localisation, preventing its binding to the transcription factor Scalloped, thereby silencing proliferation genes. There are few comparative expression data of Hippo pathway genes in non‑ model animal species and notably none in non‑bilaterian phyla.Results: All core Hippo pathway genes could be retrieved from the ctenophore Pleurobrachia pileus and the hydro‑ zoan cnidarian Clytia hemisphaerica, with the important exception of Yorkie in ctenophore. Expression study of the Hippo, Salvador and Scalloped genes in tentacle " cellular conveyor belts " of these two organisms revealed striking differences. In P. pileus, their transcripts were detected in areas where undifferentiated progenitors intensely prolifer‑ ate and where expression of cyclins B and D was also seen. In C. hemisphaerica, these three genes and Yorkie are expressed not only in the proliferating but also in the differentiation zone of the tentacle bulb and in mature tentacle cells. However, using an antibody designed against the C. hemiphaerica Yorkie protein, we show in two distinct cell lineages of the medusa that Yorkie localisation is predominantly nuclear in areas of active cell proliferation and mainly cytoplasmic elsewhere.Conclusions: This is the first evidence of nucleocytoplasmic Yorkie shift in association with the arrest of cell prolifera‑ tion in a cnidarian, strongly evoking the cell division‑promoting role of this protein and its inhibition by the activated Hippo pathway in bilaterian models. Our results furthermore highlight important differences in terms of deployment and regulation of Hippo pathway genes between cnidarians and ctenophores.
ISSN: 2041-9139

Droits : http://creativecommons.org/licenses/by/
hal-01286578
http://hal.upmc.fr/hal-01286578
http://hal.upmc.fr/hal-01286578/document
http://hal.upmc.fr/hal-01286578/file/comparative.pdf
DOI : 10.1186/s13227-016-0041-y

Éditeur(s) : HAL CCSD
Résumé : International audience
In two swordtail species of the genus Xiphophorus, the onset of puberty has been shown to be modulated at the P locus by sequence polymorphism and gene copy-number variation affecting the type 4 melanocortin hormone receptor Mc4r. The system works through the interaction of two allelic types, one encoding wild type and the other dominant-negative receptors. We have analyzed the structure and evolution of the P locus in the platyfish Xiphophorus maculatus, where as many as nine alleles of P determining the onset of sexual maturity in males and females, fecundity in females, and adult size in males are located on both the X and Y chromosomes in a region linked to the master sex-determining locus. In this species, mc4r has been amplified to up to 10 copies on both the X and Y chromosomes through recent large serial duplications. Subsequently, mc4r paralogues have diverged considerably into many different subtypes. Certain copies have acquired new untranslated regions through genomic rearrangements, and transposable element insertions and other mutations have accumulated in promoter regions, possibly explaining observed deviations from the classical mc4r transcriptional pattern. In the mc4r-coding sequence, in-frame insertions and deletions as well as nonsense and missense mutations have generated a high diversity of Mc4r-predicted proteins. Most of these variants are expressed in embryos, adults, and/or tumors. Functional receptor characterization demonstrated major divergence in pharmacological behavior for Mc4r receptors encoded by different copies of platyfish mc4r, with differences in constitutive activity as well as binding and stimulation by hormones. The high degree of allelic and copy-number variation observed between individuals can explain the high level of polymorphism for sexual maturation, fecundity, and body size in the platyfish: multiple combinations of Mc4r variants with different biochemical properties might interact to modulate the melanocortin signaling that regulates the hypothalamus-pituitary-gonadal axis.
GENETICS

hal-01544912
https://hal.archives-ouvertes.fr/hal-01544912
DOI : 10.1534/genetics.113.155952

Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : International audience
Exposure to environmental polycyclic aromatic hydrocarbons (PAHs), such as benzo(a) pyrene (B(a) P), has been linked to several health-threatening risks. PAHs were also shown to hinder adrenergic receptor (ADR) responses. As we previously demonstrated that Ba) P can directly interact with the beta 2ADR, we investigated here whether B(a) P could decrease beta 2ADR responsiveness by triggering receptor desensitization phenomena. We firstly showed that exposure to B(a) P reduced beta 2ADRmediated epinephrine-induced induction of NR4A gene mRNAs and of intracellular cAMP. Analysis of beta 2ADR protein expression demonstrated that B(a) P rapidly decreased membrane expression of beta 2ADR with a subsequent degradation of receptor protein. B(a) P exposure concomitantly rapidly increased the beta 2ADR mRNA levels. The use of the beta-blockers, propranolol and ICI 118.551, demonstrated the involvement of beta 2ADR itself in this increase. However, sustained exposure to Ba) P induced a diminution of beta 2ADR mRNA steady-state as a result of the acceleration of its degradation. Together, these results show that, beside the well-known activation of the aryl hydrocarbon receptor, PAH deleterious effects may involve the dysfunction of adrenergic responses through, in part, the desensitization of beta 2ADR. This may be taken in consideration when beta 2-agonists/antagonists are administered in patients exposed to important concentrations of PAHs, e.g. in cigarette smokers.
ISSN: 2045-2322

hal-01560151
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01560151
DOI : 10.1038/s41598-017-03646-4
PUBMED : 28607424

Éditeur(s) : HAL CCSD Wiley Open Access
Résumé : 11 pages
International audience
The loss of regulating agents such as parasites is among the most important changes in biotic interactions experienced by populations established in newly colonized areas. Under a relaxed parasite pressure, individuals investing less in costly immune mechanisms might experience a selective advantage and become successful colonizers as they re-allocate resources to other fitness-related traits. Accordingly, a refinement of the evolution of increased competitive ability (EICA) hypothesis proposed that immunity of invasive populations has evolved toward a reduced investment in innate immunity, the most costly component of immunity, and an increased humoral immunity that is less costly. Biogeographical approaches comparing populations between native and expansion ranges are particularly relevant in exploring this issue, but remain very scarce. We conducted a biogeographical comparison between populations of Spectacled Thrush (Turdus nudigenis) from the native area (South America) and from the expansion range (Caribbean islands). First, we compared haemosporidian prevalence and circulating haptoglobin (an acute-phase protein produced during inflammation). Second, we challenged captive birds from both ranges with Escherichia coli lipopolysaccharides (LPS) and measured postchallenge haptoglobin production and body mass change. Birds from the expansion range showed lower haemosporidian prevalence and lower levels of haptoglobin than birds from the native range. In addition, the inflammation elicited by LPS injection and its associated cost in terms of body mass loss were lower in birds from the expansion range than in birds from the native range. In accordance with the enemy release hypothesis, our results suggest that range expansion is associated with a reduced infection risk. Our study also supports the hypothesis that individuals from newly established populations have evolved mechanisms to dampen the inflammatory response and are in accordance with one prediction of the refined EICA hypothesis, proposed to understand biological invasions.
ISSN: 2045-7758

hal-01403291
https://hal.archives-ouvertes.fr/hal-01403291
DOI : 10.1002/ece3.2486

Éditeur(s) : HAL CCSD Springer New York
Résumé : International audience
Estrogen receptor α (ERα) exerts regulatory actions through genomic mechanisms. In the classical pathway, ligand-activated ERα binds directly to DNA through estrogen response elements (ERE) located in the promoter of target genes. ERα can also exert indirect regulation of transcription via protein-protein interaction with other transcription factors such as AP-1. Several ERα synonymous polymorphisms have been identified and efforts to understand their implications have been made. Nevertheless effects of synonymous polymorphisms are still neglected. This chapter focuses on the experimental procedure employed in order to characterize the transcriptional activity of a synonymous polymorphism of the ERα (rs746432) called Alanine 87 (Ala87). Activity of both WT and Ala87 ERα isoforms on transcriptional pathways can be analyzed in transiently transfected cells using different reporter constructs. ERα efficiency on the classical genomic pathway can be analyzed by determining its transactivation activity on an ERE-driven thymidine kinase (TK) promoter controlling the expression of the luciferase reporter gene. Transcriptional activity through the indirect genomic pathway can be analyzed by employing an AP-1 DNA response element-driven promoter also controlling the expression of luciferase reporter gene
Estrogen Receptors

ISBN : 978-1-4939-3126-2
hal-01237073
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01237073
DOI : 10.1007/978-1-4939-3127-9_22

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The catecholamine epinephrine is known to repress expression of hepatic drug metabolizing enzymes such as cytochromes P-450. The present study was designed to determine whether epinephrine may also target expression of main hepatic drug transporters, that play a major role in liver detoxification and are commonly coordinately regulated with drug detoxifying enzymes. Treatment of primary human hepatocytes with 10 mu M epinephrine for 24 h repressed mRNA expression of various transporters, such as the sinusoidal influx transporters NTCP, OATP1B1, OATP2B1, OAT2, OAT7 and OCT1 and the efflux transporters MRP2, MRP3 and BSEP, whereas it induced that of MDR1, but failed to alter that of BCRP. Most of these changes in transporter mRNA levels were also found in epinephrine-exposed human highly-differentiated hepatoma HepaRG cells, which additionally exhibited reduced protein expression of OATP2B1 and MRP3, increased expression of P-glycoprotein and decreased transport activity of NTCP, OATPs and OCT1. Epinephrine effects towards transporter mRNA expression in human hepatocytes were next shown to be correlated to those of the selective beta 2-adrenoreceptor (ADR) agonist fenoterol, of the adenylate cyclase activator forskolin and of the cAMP analogue 8-bromo-cAMP. In addition, the non-selective beta-ADR antagonist carazolol and the selective beta 2-ADR antagonist ICI-118,551, unlike the alpha-ADR antagonist phentolamine, suppressed epinephrine -mediated repressions of transporter mRNA expression. Taken together, these data indicate that epinephrine regulates in vitro expression of main hepatic drug transporters in a beta 2-ADR/adenylate cyclase/cAMP-dependent manner. Hepatic drug transport appears therefore as a target of the beta 2-adrenergic system, which may have to deserve attention for drugs interacting with beta 2-ADRs.
ISSN: 0928-0987

hal-01578583
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01578583
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01578583/file/Mayati%20et%20al.%20-%20%CE%B22-adrenergic%20receptor-mediated%20in%20vitro%20regulatio.pdf
DOI : 10.1016/j.ejps.2017.06.010
PUBMED : 28603032

Éditeur(s) : HAL CCSD American Association for Cancer Research
Résumé : International audience
Homing of CD8+ T lymphocytes to the tumor microenvironment is an important step for mounting a robust antitumor immune response. TGF-β is responsible for CD103 (αEβ7) integrin induction in activated intraepithelial CD8+ T lymphocytes. However, the interplay between TGF-β and CD103 and their contribution to T-cell infiltration and antitumor activity remain unknown. Here, we used viable human lung tumor slices and autologous tumor antigen-specific T-lymphocyte clones to provide evidence that CD103 is directly involved in T-lymphocyte recruitment within epithelial tumor islets and intratumoral early T-cell signaling. Moreover, TGF-β enhanced CD103-dependent T-cell adhesion and signaling, whereas it inhibited leukocyte function-associated antigen (LFA)-1 (αLβ2) integrin expression and LFA-1-mediated T-lymphocyte functions. Mechanistic investigations revealed that TGF-β bound to its receptors (TGFBR), which promoted the recruitment and phosphorylation of integrin-linked kinase (ILK) by TGFBR1. We further show that ILK interacted with the CD103 intracellular domain, resulting in protein kinase B (PKB)/AKT activation thereby initiating integrin inside-out signaling. Collectively, our findings suggest that the abundance of TGF-β in the tumor microenvironment may in fact engage with integrin signaling pathways to promote T-lymphocyte antitumor functions, with potential implications for T-cell-based immunotherapies for cancer
ISSN: 0008-5472

Droits : info:eu-repo/semantics/OpenAccess
hal-01282442
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01282442
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01282442/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01282442/file/TGF%CE%B2%20Signaling%20Intersects%20with%20CD103-boutet2016-final.pdf
DOI : 10.1158/0008-5472.CAN-15-1545

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Analysis of microbial biodiversity is hampered by a lack of reference genomes from most bacteria, viruses, and algae. This necessitates either the cultivation of a restricted number of species for standard sequencing projects or the analysis of highly complex environmental DNA metagenome data. Single-cell genomics (SCG) offers a solution to this problem by constraining the studied DNA sample to an individual cell and its associated symbionts, prey, and pathogens. We used SCG to study marine heterotrophic amoebae related to Paulinella ovalis (A. Wulff) P.W. Johnson, P.E. Hargraves & J.M. Sieburth (Rhizaria). The genus Paulinella is best known for its photosynthetic members such as P.chromatophora Lauterborn that is the only case of plastid primary endosymbiosis known outside of algae and plants. Here, we studied the phagotrophic sister taxa of P.chromatophora that are related to P.ovalis and found one SCG assembly to contain -cyanobacterial DNA. These cyanobacterial contigs are presumably derived from prey. We also uncovered an associated cyanophage lineage (provisionally named phage PoL_MC2). Phylogenomic analysis of the fragmented genome assembly suggested a minimum genome size of 200Kbp for phage PoL_MC2 that encodes 179 proteins and is most closely related to Synechococcus phage S-SM2. For this phage, gene network analysis demonstrates a highly modular genome structure typical of other cyanophages. Our work demonstrates that SCG is a powerful approach for discovering algal and protist biodiversity and for elucidating biotic interactions in natural samples.
ISSN: 0022-3646

hal-01544797
https://hal.archives-ouvertes.fr/hal-01544797
DOI : 10.1111/jpy.12028