Review: placenta-specific microRNAs in exosomes - good things come in nano-packages.

MicroRNAs (miRNAs) are small noncoding RNA gene products that commonly regulate mRNA expression by repression of translation and/or transcript decay. Whereas common and unique types of miRNAs are expressed by the placenta during pregnancy, the functions of most placental miRNA species are unknown. In addition to their intracellular silencing function, miRNAs are also released to the extracellular space and systemic circulation, where they can potentially target cells to regulate mRNA and protein expression, providing a non-hormonal means of intercellular communication that contributes to tissue homeostasis and disease pathophysiology. This review centers on extracellular miRNAs that originate in trophoblasts and that could mediate crosstalk between the feto-placental unit and the mother during pregnancy. We specifically detail the function of miRNAs from the primate-specific chromosome 19 miRNA cluster. These miRNAs are highly expressed in human placentas and in the serum of pregnant women. They are also packaged into extracellular vesicles of diverse sizes, including exosomes, and endow non-trophoblastic cells with resistance to a variety of viruses.

The expression profile of C19MC microRNAs in primary human trophoblast cells and exosomes.

The largest gene cluster of human microRNAs (miRNAs), the chromosome 19 miRNA cluster (C19MC), is exclusively expressed in the placenta and in undifferentiated cells. The precise expression pattern and function of C19MC members are unknown. We sought to profile the relative expression of C19MC miRNAs in primary human trophoblast (PHT) cells and exosomes. Using high-throughput profiling, confirmed by PCR, we found that C19MC miRNAs are among the most abundant miRNAs in term human trophoblasts. Hypoxic stress selectively reduced miR-520c-3p expression at certain time-points with no effect on other C19MC miRNAs. Similarly, differentiation in vitro had a negligible effect on C19MC miRNAs. We found that C19MC miRNAs are the predominant miRNA species expressed in exosomes released from PHT, resembling the profile of trophoblastic cellular miRNA. Predictably, we detected the similar levels of circulating C19MC miRNAs in the serum of healthy pregnant women at term and in women with pregnancies complicated by fetal growth restriction. Our data define the relative expression levels of C19MC miRNAs in trophoblasts and exosomes, and suggest that C19MC miRNAs function in placental-maternal signaling.

The levels of hypoxia-regulated microRNAs in plasma of pregnant women with fetal growth restriction.

MicroRNAs (miRNAs) are short non-coding RNAs that regulate gene expression at the post-transcriptional level. While mostly intracellular, a portion of cellular miRNAs is released to the circulation and their level in the plasma is altered in certain pathological conditions such as cancer, and also during pregnancy. We examined the circulating levels of a set of trophoblastic miRNAs, which we recently found to be regulated by hypoxia, in the plasma of pregnant women with fetal growth restriction (FGR). Pregnancy was associated with increased plasma levels of several placenta-specific miRNAs, compared to non-pregnant controls. Among pregnant women, the overall levels of miRNA species that we analyzed were increased by 1.84-fold (p < or = 0.01) in plasma of women with pregnancies complicated by FGR, but decreased in FGR placentas by 24% (p < or = 0.01) compared to values from uncomplicated pregnancies. Together, our results show that plasma concentration of miRNAs is regulated in pregnancy, and that FGR is associated with increased circulating miRNA levels, highlighting the need to explore plasma miRNAs as potential biomarkers for placental diseases.

[Benign positional vertigo, an armchair for diagnosis and for treatment: description and significance]. / Vertige positionnel paroxystique bénin, un fauteuil au service du diagnostic et du traitement: description et intérêt.

OBJECTIVES: The benign positional vertigo is a very frequent pathology. It requires to establish the diagnosis, to fixe the head in some positions to get various nystagmus which are observed directly or by video-nystagmoscopy or analyzed by video-nystagmography. PURPOSE: To describe the diagnostic and therapeutical interests of a special armchair, now available, whose characteristics are to be able to swivel around two axes of vertical and horizontal rotations, the patient being completely interdependent of the armchair. It thus makes it possible to place the patient's head in position wished with a high degree of accuracy and facility. METHODS: After a short description of the characteristics of armchairs classically used, the authors describe in detail this new armchair Its geometrical characteristics are reported and its capacities, like its mode of use: fixing of the patient with armchair then mobilization of the unit "armchair-patient" and setting in position of the head at the point of the space desired by the ENT. RESULTS: The authors report the main advantages of this armchair. It allows a great accuracy of movement given to the semicircular canals, a possible mobilization with an amplitude until there ever reached, a significant reduction of the proprioceptive entries of patient, a perfect safety of the examination, a possible mobilization of obese or arthritic patients and, finally, a very increased comfort for the patient himself. Finally future technological developments possible are brought back. CONCLUSION: Thanks to the use of the armchair of mechanical assistance, the diagnosis and treatment of benign positional vertigo appear more certain, more precise and more practical at the same time for the medical doctor and the patients. A multicentric study is in process to show its interest in this pathology.

Differential control of gene activity by isoforms A, B1 and B2 of the Drosophila ecdysone receptor.

The steroid hormone ecdysone initiates molting and metamorphosis in Drosophila via a heterodimeric receptor consisting of EcR that binds hormone, and USP, a homolog of the vertebrate RXR receptor. EcR exists in three isoforms EcRA, EcRB1 and EcRB2 that are thought to direct specific physiological responses to ecdysone. These three isoforms differ only in their N-terminal A/B domain that implies that sequences responsible for the differential physiological effects lie within the A/B domains of the EcR isoforms. In the present study, we set out to determine the capability of the three isoforms and their A/B domains to control gene transcription. When full-length EcR plasmids were cotransfected into mammalian cells with a USP expressing and a cognate reporter plasmid, the three EcR isoforms showed striking differences in their ability to control gene transcription, both in the presence and in the absence of hormone. Furthermore, the A/B domains of EcRB1 and of EcRB2 when fused to the GAL4 DNA binding domain are sufficient to activate transcription of a reporter gene, in yeast as well as in mammalian cells. In contrast, a fusion construct containing the A/B domain of EcRA represses basal transcription of the reporter gene. All these findings emphasize the importance of the A/B domains of the three EcR isoforms for differentially controlling gene transcription. Furthermore, they provide evidence for the existence of an autonomous ligand-independent activation function (AF1) in the A/B domains of EcRB1 and EcRB2 and of an inhibitory function (IF) in the A/B domain of EcRA.

The DEAD box protein DP103 is a regulator of steroidogenic factor-1.

The nuclear receptor steroidogenic factor-1 (SF-1) is essential for development of the gonads, adrenal gland, and the ventromedial hypothalamic nucleus. It also regulates the expression of pivotal steroidogenic enzymes and other important proteins in the reproductive system. We sought to elucidate the mechanisms that govern the transcriptional activity of SF-1. We demonstrate here that a previously uncharacterized domain, located C-terminal to the DNA binding domain of SF-1, exhibits transcriptional repression function. Point mutations in this domain markedly potentiate the transcriptional activity of native SF-1. Using an SF-1 region that spans this proximal repression domain as bait in a yeast two-hybrid system, we cloned an SF-1 interacting protein that is homologous to human DP103, a member of the DEAD box family of putative RNA helicases. DP103 directly interacts with the proximal repression domain of SF-1, and mutations in this domain abrogate its interaction with DP103. DP103 is expressed predominantly in the testis and is also expressed at a lower level in other steroidogenic and nonsteroidogenic tissues. Functionally, DP103 exhibits a native transcriptional repression function that localizes to the C-terminal region of the protein and represses the activity of wild-type, but not mutant, SF-1. Together, the physical and functional interaction of DP103 with a previously unrecognized repression domain within SF-1 represents a novel mechanism for regulation of SF-1 activity.

Cloning and characterization of new orphan nuclear receptors and their developmental profiles during Tenebrio metamorphosis.

Five PCR fragments corresponding to a part of the DNA-binding domain of different hormone nuclear receptors were isolated from Tenebrio molitor mRNAs. The sequence identity of three of them with known Drosophila nuclear receptors strongly suggests that they are the Tenebrio orthologs of seven-up, DHR3 and beta-FTZ-F1, and thus named Tmsvp, TmHR3 and TmFTZ-F1. The full-length sequences of the other two were established. TmHR78 is either a new receptor of the DHR78 family or the same gene which has evolved rapidly, particularly in the E domain. TmGRF belongs to the GCNF1 family and its in vitro translated product binds to the extended half site TCAAGGTCA with high affinity. The periods of expression of the corresponding transcripts in epidermal cells during Tenebrio metamorphosis were analyzed as a function of 20-hydroxyecdysone titers measured in the hemolymph of the animals taken for RNA extraction. Comparison of the expression profiles of these nuclear receptors with those observed during Drosophila metamorphosis revealed similar temporal correlations as a function of ecdysteroid variations, which further supported the sequence identity data for TmSVP, TmHR3, TmFTZ-F1 and TmHR78.

Cloning of two putative ecdysteroid receptor isoforms from Tenebrio molitor and their developmental expression in the epidermis during metamorphosis.

Using the Drosophila EcR-B1 cDNA as a probe, we have cloned the putative ecdysteroid receptor from the mealworm Tenebrio molitor. We have isolated two cDNAs with different 5' termini that contain a complete open reading frame. These two cDNAs encode two proteins with distinct N-terminal regions corresponding to two isoforms. The coleopteran receptor is obviously related to the ecdysteroid receptor of other insects, but shares only 89% and 61% amino acid identities with the DNA-binding and ligand-binding domains of the Drosophila receptor, respectively. Its expression pattern has been examined in the epidermis during the last larval instar and pupal stage of T. molitor, in correlation with the hemolymph ecdysteroid titer. Hybridizations revealed two transcripts of 7 kb and 6.5 kb detected in most stages during metamorphosis and corresponding to the A and B1 isoforms. These two mRNAs are highly evident just before the rise of each ecdysteroid peak both in prepupae and in pupae. They show almost the same expression pattern in epidermis except for the second part of the pupal stage, during which only the A isoform is detected.

[Hyperfractionated radiotherapy in 56 patients with tumors of the head and neck (author's transl)]. / Etude de la radiothérapie hyperfractionnée chez 56 patients atteints de tumeurs de la tête et du cou.

A new method of irradiation known as hyperfractionated radiotherapy was studied in 56 patients with cancers in the region of the ear, nose, and throat. The dose was 72 grays given during 80 sessions over a period of 28 days, with a rest period of two weeks at the half-way point. Each session lasted 2 hours. The results (complications and survival rate) were compared with those obtained in a control group treated with 70 grays in 35 sessions over a period of 7 weeks. The complication rate was 21% in the series treated with hyperfractionated radiotherapy, against 19% in those given classical treatment (results not significant). The survival rate was better, however, (63% against 33% after 18 months), for the patients treated with this new method of irradiation.