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

Steroids from the starfish Euretaster insignis: a novel group of sulfated 3β,21-dihydroxysteroids

Two groups of sterol sulfates were obtained from aq. exts. of E. insignis. The more polar components are sulfated 3β,21-dihydroxy steroids; after solvolysis to remove the sulfate groups these were identified as I [R = H, R1 = (CH2)2C(:CH2)CHMe2 (Q), CH:CHCHMeCHMe2-(E), (CH2)3CHMe2 (Q1), CH:CHCH2CHMe2-(E); R2 = bond, R1 = Q, Q1]. The less polar components are sterol sulfates, which are normal constituents of starfish. The free sterol mixt. contained a low level of cholest-7-en-3β-ol and C26-29 5α-sterols. These findings may explain the apparent absence of asterosaponins in this species

Epidemiologic study in pregnant women from Amiens (Picardy). Need of a national stydy.

Il s'agit d'une enquête réalisée à Amiens du 1er mars 1993 au 28 février 1994 chez les femmes venant d'accoucher pour évaluer leur niveau d'immunité vis à vis de la toxoplasmose et leur connaissances des mesures préventives. L'analyse des données s'est faite grâce au locigiel Epidemio sur un total de 987 femmes. La séroprévalence est de 58% et l'analyse montre que c'est la consommation de viande peu ou pas cuite et la présence d'un chat dans l'entourage qui sont les 2 facteurs de risque majeurs. La quasi totalité des femmes a pu citer au moins 2 moyens de prévention efficaces et les reccommandations sont largement suivies. En conclusion, les résultats sont rassurants. Cependant, une enquête nationale serait nécessaire pour permettre une évaluation sur le plan national

Identification of odorant receptors from the alpine marmot (Marmota marmota)

International audienceAlpine Marmots (Marmota marmota) are a good model to study intraspecific chemical communication among mammals. This species has been subjected to several behavioural and biochemical studies regarding both their scent-marking behaviour by cheek-rubbing, and the chemical composition of their glandular secretions. However, no molecular study has been undertaken until today on proteins from the olfactory epithelium possibly implicated in chemical perception. In this study, we identified, to our knowledge for the first time, some olfatory receptors from this wild rodent. Starting with olfactory epithelium of an Alpine Marmot, and by mean of reverse transcriptase polymerase chain reaction technique (RT-PCR), we isolated fourteen partial sequences that exhibited a high degree of homology (45-92%) with olfactory receptors from other vertebrates. Conserved identities and structural features clearly defined these Alpine Marmot sequences as members of the seven transmembrane domain olfactory receptors. All sequences were observed as belonging to known olfactory receptor families and were classified into ten subfamilies of the tetrapods OR class. Finally, Northern blot analysis revealed specific expression of these sequences in the Alpine Marmot olfactory epithelium tissue

Exploration of nuclear body-enhanced sumoylation reveals that PML represses 2-cell features of embryonic stem cells

International audienceMembrane-less organelles are condensates formed by phase separation whose functions often remain enigmatic. Upon oxidative stress, PML scaffolds Nuclear Bodies (NBs) to regulate senescence or metabolic adaptation. PML NBs recruit many partner proteins, but the actual biochemical mechanism underlying their pleiotropic functions remains elusive. Similarly, PML role in embryonic stem cell (ESC) and retro-element biology is unsettled. Here we demonstrate that PML is essential for oxidative stress-driven partner SUMO2/3 conjugation in mouse ESCs (mESCs) or leukemia, a process often followed by their poly-ubiquitination and degradation. Functionally, PML is required for stress responses in mESCs. Differential proteomics unravel the KAP1 complex as a PML NB-dependent SUMO2-target in arsenic-treated APL mice or mESCs. PML-driven KAP1 sumoylation enables activation of this key epigenetic repressor implicated in retro-element silencing. Accordingly, Pml −/− mESCs re-express transposable elements and display 2-Cell-Like features, the latter enforced by PML-controlled SUMO2-conjugation of DPPA2. Thus, PML orchestrates mESC state by coordinating SUMO2-conjugation of different transcriptional regulators, raising new hypotheses about PML roles in cancer