Aldo Keto Reductase 1B7 and Prostaglandin F2α Are Regulators of Adrenal Endocrine Functions

Prostaglandin F2α (PGF2α), represses ovarian steroidogenesis and initiates parturition in mammals but its impact on adrenal gland is unknown. Prostaglandins biosynthesis depends on the sequential action of upstream cyclooxygenases (COX) and terminal synthases but no PGF2α synthases (PGFS) were functionally identified in mammalian cells. In vitro, the most efficient mammalian PGFS belong to aldo-keto reductase 1B (AKR1B) family. The adrenal gland is a major site of AKR1B expression in both human (AKR1B1) and mouse (AKR1B3, AKR1B7). Thus, we examined the PGF2α biosynthetic pathway and its functional impact on both cortical and medullary zones. Both compartments produced PGF2α but expressed different biosynthetic isozymes. In chromaffin cells, PGF2α secretion appeared constitutive and correlated to continuous expression of COX1 and AKR1B3. In steroidogenic cells, PGF2α secretion was stimulated by adrenocorticotropic hormone (ACTH) and correlated to ACTH-responsiveness of both COX2 and AKR1B7/B1. The pivotal role of AKR1B7 in ACTH-induced PGF2α release and functional coupling with COX2 was demonstrated using over- and down-expression in cell lines. PGF2α receptor was only detected in chromaffin cells, making medulla the primary target of PGF2α action. By comparing PGF2α-responsiveness of isolated cells and whole adrenal cultures, we demonstrated that PGF2α repressed glucocorticoid secretion by an indirect mechanism involving a decrease in catecholamine release which in turn decreased adrenal steroidogenesis. PGF2α may be regarded as a negative autocrine/paracrine regulator within a novel intra-adrenal feedback loop. The coordinated cell-specific regulation of COX2 and AKR1B7 ensures the generation of this stress-induced corticostatic signal

Repenser l’éducation face à la crise écologique et ses conséquences sur la santé

International audienc

Strategy for Successful Integration of eDNA-based Methods in Aquatic Monitoring

Recent developments in the use of environmental DNA are opening up new horizons for the assessment of the quality of aquatic environments. These rapid and cost-effective methods, in very swift progress, will potentially offer the opportunity to identify all the taxa present in an environmental sample (water or biota) by the use of complementary markers. The produced inventories can then be used for the assessment of biodiversity and ecological quality. However, the inclusion of these new DNA-based methods in monitoring practices is not straightforward and requires harmonised actions in the coming years at national and international levels.In order to foresee and stimulate such a harmonised implementation, the European network DNAqua-Net (COST Action CA15219) brought together some of its members, experts of ECOSTAT and other environmental biomonitoring stakeholders from different European countries. Through workshops, bringing together 51 participants in 7 sub-groups in April 2020, an implementation roadmap was designed. The coordinated actions to be taken in the different countries, and the possible collaborations and steps to be taken at the EU level were identified.This presentation will give an overview of all discussions (Lefrançois et al. 2020) reflecting the diversity of situations in Europe, as well as common views. We will highlight important actions required for a successful implementation of DNA-based biomonitoring of aquatic ecosystems to the horizon of 2030

Guide d'identification : les diatomées benthiques des cours d'eau de Nouvelle-Calédonie vol.2

Benthic diatoms have long been considered as an interesting compartment for monitoring aquatic environments quality. Then, within the implementation of the Water Framework Directive (WFD), adopted since 10/23/2000, they are identified as one of the key biological quality elements, making it possible to assess the ecological status of different categories of aquatic environments, including rivers from continental Europe and certain overseas territories. Because of its legal status, New Caledonia is not really part of the European Union and WFD has no legal vocation for application there. However, integrated and sustainable management of water resources is an important concern for local authorities and managers. In order to complete the ecological information already provided on watercourses by 2 biological indices based on benthic invertebrates (the Biotic Index of New Caledonia or IBNC, developed since 1999, and the recent Bio-Sedimentary Index or IBS), on the initiative of the OEIL and with the support of DAVAR and CNRT, a Research & Development Program aiming at the development of a new diatomic index has been implemented under responsibility of the Asconit-Irstea consortium, assisted by the local private consultant Bioeko. Carried out between October 2012 and 2017, this program enabled the acquisition of 210 complete surveys coupling diatomic inventories and physico-chemical conditions at the station, collected during 4 sampling campaigns covering the 2 main climatic seasons. At the toltal, 466 different taxa could be inventoried, many of which being previously poorly known or even unknown.Function of the quantity of ecological information capitalized, 217 sufficiently encountered freshwater taxa participate in the calculation of the new IDNC. Many of them do not provide specific information on the level of anthropogenic alteration of the river (Taxons +). Other taxa with a distribution clearly favored by anthropogenic pressure gradients were selected using the TITAN software, and constitute alert taxa (Taxa -). Specific lists of alert taxa have thus been identified with respect to 7 different anthropogenic gradients.This iconographic guide is intended to allow the reliable identification of the IDNC's taxa (i.e. taxa really participating in the calculation of the index score). Some marine taxa identified during the study are also illustrated. It is useful to recognize them: indeed, their identification in more than marginal numbers in a given sample would be a sign of a coastal influence exerted at the level of the sampled site (transition zone), such a situation getting outside the validity domain of IDNC.This identification guide consists of 2 volumes: Volume 1 describes each index taxon individually. Volume 2 (i.e. this document) compiles illustrations of morphologically-close taxa in order to be able to compare them and facilitate their routine identification.Les diatomées benthiques sont considérées de longue date comme un compartiment d'intérêt pour surveiller la qualité des milieux aquatiques. Aussi, dans le cadre d'application de la Directive-Cadre sur l'Eau (DCE), adoptée depuis le 23/10/2000, elles ont été identifiées comme l'un des maillon-clés permettant d'évaluer l'état écologique de différentes catégories de milieux aquatiques de l'Europe continentale et de certains territoires ultramarins, dont les cours d'eau. Du fait de son statut juridique, la Nouvelle-Calédonie n'est pas partie intégrante de l'Union Européenne et la DCE n'a pas vocation légale à s'appliquer. Cependant, la gestion intégrée et durable de la ressource en eau est une préoccupation importante des autorités et gestionnaires locaux. Afin de venir compléter l'information écologique déjà apportée sur les cours d'eau par 2 indices biologiques basés sur les invertébrés benthiques (l'Indice Biotique de Nouvelle-Calédonie ou IBNC, mis au point depuis 1999, et l'Indice Bio-Sédimentaire ou IBS, de production plus récente), à l'initiative de l'OEIL et avec l'appui de la DAVAR et du CNRT, un programme de Recherche-Développement visant la mise au point d'un nouvel indice diatomique a été mis en place, dont la réalisation a été confiée au consortium Asconit-Irstea, avec l'appui du bureau d'études local Bioeko. Réalisé entre Octobre 2012 et 2017, ce programme a permis l'acquisition de 210 relevés complets couplant inventaires diatomiques et conditions physico-chimiques à la station, collectés au cours de 4 campagnes de prélèvement couvrant les 2 saisons climatiques principales. En tout, 466 taxons différents, ont pu être inventoriés, dont beaucoup étaient antérieurement mal connus voire inconnus.En fonction du niveau d'information écologique capitalisé, 217 taxons d'eau douce suffisamment rencontrés participent effectivement au calcul du nouvel IDNC. Bon nombre d'entre eux n'apportent pas d'information particulière sur le niveau d'altération anthropique de la rivière (Taxons +). D'autres taxons, à répartition clairement favorisée par des gradients de pression anthropique, ont été sélectionnés à l'aide du logiciel TITAN et constituent des taxons d'alerte (Taxons -). Des listes spécifiques de taxons d'alerte ont ainsi été identifiées vis-à-vis de 7 gradients différents d'anthropisation.Le présent guide iconographique est destiné à permettre l'identification fiable des taxons indiciels de l'IDNC (i.e. les taxons qui participent effectivement au calcul de la note indicielle). Quelques taxons halins identifiés en cours d'étude sont également illustrés. Il est utile de les reconnaître. En effet, leur identification dans un effectif plus que marginal dans un relevé donné serait le signe d'une influence littorale exercée au niveau du site prélevé (zone de transition), situation particulière sortant du domaine de validité de l'IDNC.Le présent guide d'identification est composé de 2 volumes : le Volume 1 décrit chaque taxon indiciel individuellement. Le Volume 2 (présent document) compile des illustrations de taxons morphologiquement proches afin de pouvoir les comparer et de faciliter leur identification en routine

Physical properties of epilithic river biofilm as a new lead to perform pollution bioassessments in overseas territories

International audienceChlordecone (CLD) levels measured in the rivers of the French West Indies were among the highest values detected worldwide in freshwater ecosystems, and its contamination is recognised as a severe health, environmental, agricultural, economic, and social issue. In these tropical volcanic islands, rivers show strong originalities as simplified food webs, or numerous amphidromous migrating species, making the bioindication of contaminations a difficult issue. The objective of this study was to search for biological responses to CLD pollution in a spatially fixed and long-lasting component of the rivers in the West Indies: the epilithic biofilm. Physical properties were investigated through complementary analyses: friction, viscosity as well as surface adhesion were analyzed and coupled with measures of biofilm carbon content and exopolymeric substance (EPS) production. Our results have pointed out a mesoscale chemical and physical reactivity of the biofilm that can be correlated with CLD contamination. We were able to demonstrate that epilithic biofilm physical properties can effectively be used to infer freshwater environmental quality of French Antilles rivers. The friction coefficient is reactive to contamination and well correlated to carbon content and EPS production. Monitoring biofilm physical properties could offer many advantages to potential users in terms of effectiveness and ease of use, rather than more complex or time-consuming analyses. Out of the 11,435 French water bodies analysed for quality compliance according to regulations imposed by European legislation, 10% are located between the tropics and the equator, thousands of kilometres away from European shores 1. In the outermost tropical territories, climatic characteristics often result in highly turbulent tropical streams 2 that support simplified ecosystems with very few primary producers. Due to high river flow, perennial phytoplankton, zooplankton and macroalgae are scarce or missing and the epilithic biofilm deserves here, even more than elsewhere, the comparison with a real productive and contributive "microbial skin" 3. The epilithic biofilm is the only endogenous long-lasting primary producer that grows on submersed river stones and is largely exploited as a food source by all diadromous fish or crustaceans 4,5. In these countries, the simplified food webs and the massive flows of post-larvae and juveniles regularly re-entering the rivers and migratin

Dispersion des métaux de la mine au lagon : rôle du compartiment atmosphérique et dispersion au sein du compartiment biotique dulçaquicole et estuarien. Rapport scientifique final

- Ce rapport du programme DMML « Dispersion des métaux de la mine au lagon » constitue le volume 1 (sur 4) du programme intégré « Dispersion et exposition humaine aux métaux en Nouvelle-Calédonie » composé de 3 projets (DMML, Dynamine, Métexpo) étudiant les métaux et leur toxicité sur des sites pilotes similaires.- Le programme DMML a proposé de caractériser le potentiel de dispersion des éléments métalliques traces (ETM) Ni, Cr, Co et Mn au sein des compartiments abiotiques (atmosphère et pédosphère) et d’évaluer la contamination métallique dans le compartiment biotique de l’hydrosphère ainsi que de déterminer les mécanismes de transferts trophiques. - La caractérisation des flux d’ETM au sein de l’hydrosphère est réalisée dans le programme « Dynamine »

Role of PGF_2α in adrenal endocrine functions.

<p><i>A</i>, ELISA quantification of PGF_2α release by chromaffin MPC862L cells untreated (control) or treated with 10⁻⁶ M dexamethasone for 12 h (dex). <i>B</i>, HPLC quantification of dopamine secretion by MPC862L cells cultured in absence or presence of 10⁻⁷ M cloprostenol (clo) (PGF_2α analogue) used either alone or in combination with 10⁻⁶ M dexamethasone for 12 h (clo+dex). Values are the mean of 3 experiments ± S.D. *, <i>P</i><0.05, ** <i>P</i><0.01. <i>C</i>, Typical perifusion profiles illustrating the effects of increasing concentrations of PGF_2α (0.1 µM to 10 µM) and cloprostenol (0.1 nM to 1 µM) on corticosterone secretion. Horizontal bars indicate the start point and duration of PGF_2α or cloprostenol infusions. <i>D</i>, Semi-logarithmic plot showing the effect of increasing concentrations of PGF_2α and cloprostenol on the inhibition of corticosterone secretion. Results are expressed as a percentage of the basal secretory rate. Experimental values were calculated from data similar to those presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0007309#pone-0007309-g005" target="_blank">Fig. 5</a><i>C</i>. Each curve represents the mean ± SEM of 6 to 12 independent experiments. After stabilization, the mean secretion rate of corticosterone in basal condition was 251±14 pg/min per adrenal. The concentration-response curve was fitted using the Prism program (GraphPad Software, Inc., San Diego, CA). **<i>P<0.001</i>.</p

Differential expression of AKR1Bs, COXs and FP receptor proteins in cell cultures from adrenal cortex and from adrenal <i>medulla</i>.

<p><i>A</i>, Time-dependent response to 10⁻⁵ M forskolin treatment of StAR, AKR1Bs, COXs and FP receptor proteins levels in adrenocortical Y1 cell line was analyzed by western blot. Whole adrenal protein extract was used as a positive control, (ad.). <i>B</i>, Expression levels of AKR1Bs, COXs and FP receptor proteins were analyzed by western-blot in the chromaffin MPC862L cell line either untreated (ctrl) or treated with 10⁻⁶ M dexamethasone (dex) for 12 h. These levels were compared to the levels observed in Y1 cells stimulated by 10⁻⁵ M forskolin (Fsk) for 6 h (ns, non specific signal). <i>C</i>, FP receptor expression in primary cell cultures of rat adrenal cortical and medullary cells. AKR1B7 and TH positive signals were used as markers of steroidogenic and chromaffin identity, respectively. Molecular weights are indicated on the right.</p

Hormonal sensitivity of PGF_2α production in rodent adrenocortical cells and involvement of AKR1B7 protein in PGF_2α production.

<p><i>A</i>, Western-blot analysis of AKR1Bs and COX2 proteins accumulation in stably transfected Y1 cell clones expressing AKR1B7 (empty vector EV2) or devoid of AKR1B7 (antisense vector AS19) untreated or treated with 10⁻⁵ M forskolin (Fsk) for 6 h. Molecular weight markers are shown on the right. <i>B</i>, ELISA quantification of PGF_2α in media from stably transfected Y1 cell clones expressing AKR1B7 (EV2) or devoid of AKR1B7 (AS19), untreated or treated with 10⁻⁵ M forskolin for 6 h. <i>C</i>, Differential expression of AKR1Bs and COX2 proteins in primary cultures of rat cortical cells treated with vehicle (ctrl) or with 10⁻⁹ M ACTH for 6 h or 12 h. <i>D</i>, ELISA quantification of PGF_2α release in media from rat adrenocortical primary cells, cultured in the absence or presence of 10⁻⁹ M ACTH for 6 h. Values are the mean of 3 experiments ± S.D. *, <i>P</i><0.05, ** <i>P</i><0.01.</p

Functional cellular coupling between COX2 and AKR1B7.

<p><i>A</i>, Western blot analysis of six different HEK293 clones stably transfected with COX2 expression vector in combination with empty vector (COX2, clones 3, 4, 5) or AKR1B7 expression vector (COX2-AKR1B7, clones 3, 7, 14). <i>B</i>, ELISA quantification of PGF_2α in media from stably transfected HEK293 cell clones, expressing COX2 alone (COX2-3, -4, -5) or in combination with AKR1B7 (COX2-AKR1B7-3, -7, -14). Cells were stimulated for 30 min with 10 µM A23187 ionophore and culture media were used for PGF_2α quantification. Values were expressed as the mean of 4 experiments ± S.D. <i>Asterisks</i> point values significantly different from the release of PGF_2α by the COX2-4 cell clone. *, <i>P</i><0.05, **, <i>P</i><0.01. <i>C</i>, Subcellular localization of AKR1B7, AKR1B3, AKR1B8 and COX2 in Y1 adrenocortical cells was analysed by western-blot. Protein extracts (40 µg/lane) from nuclear (Nuc), heavy membrane (HM), light membrane (LM) and cytosolic fractions (Cyt) of Y1 adrenocortical cells untreated or treated with 10⁻⁵ M forskolin for 6 h were subjected to western blot analysis. StAR and SF1 signals were used as markers of heavy membrane fraction and nuclear fraction respectively. Molecular weight markers are shown on the right.</p