The role of miR-155 in cigarette smoke-induced pulmonary inflammation and COPD.

Chronic obstructive pulmonary disease (COPD) is a highly prevalent respiratory disease characterized by airflow limitation and chronic inflammation. MiR-155 is described as an ancient regulator of the immune system. Our objective was to establish a role for miR-155 in cigarette smoke (CS)-induced inflammation and COPD. We demonstrate increased miR-155 expression by RT-qPCR in lung tissue of smokers without airflow limitation and patients with COPD compared to never smokers and in lung tissue and alveolar macrophages of CS-exposed mice compared to air-exposed mice. In addition, we exposed wild type and miR-155 deficient mice to CS and show an attenuated inflammatory profile in the latter. Alveolar macrophages were sorted by FACS from the different experimental groups and their gene expression profile was analyzed by RNA sequencing. This analysis revealed increased expression of miR-155 targets and an attenuation of the CS-induced increase in inflammation-related genes in miR-155 deficient mice. Moreover, intranasal instillation of a specific miR-155 inhibitor attenuated the CS-induced pulmonary inflammation in mice. Finally, elastase-induced emphysema and lung functional changes were significantly attenuated in miR-155 deficient mice. In conclusion, we highlight a role for miR-155 in CS-induced inflammation and the pathogenesis of COPD, implicating miR-155 as a new therapeutic target in COPD.

Direct comparison of distinct naive pluripotent states in human embryonic stem cells.

Until recently, human embryonic stem cells (hESCs) were shown to exist in a state of primed pluripotency, while mouse embryonic stem cells (mESCs) display a naive or primed pluripotent state. Here we show the rapid conversion of in-house-derived primed hESCs on mouse embryonic feeder layer (MEF) to a naive state within 5-6 days in naive conversion media (NCM-MEF), 6-10 days in naive human stem cell media (NHSM-MEF) and 14-20 days using the reverse-toggle protocol (RT-MEF). We further observe enhanced unbiased lineage-specific differentiation potential of naive hESCs converted in NCM-MEF, however, all naive hESCs fail to differentiate towards functional cell types. RNA-seq analysis reveals a divergent role of PI3K/AKT/mTORC signalling, specifically of the mTORC2 subunit, in the different naive hESCs. Overall, we demonstrate a direct evaluation of several naive culture conditions performed in the same laboratory, thereby contributing to an unbiased, more in-depth understanding of different naive hESCs.

MicroRNA-193b-3p acts as a tumor suppressor by targeting the MYB oncogene in T-cell acute lymphoblastic leukemia.

The MYB oncogene is a leucine zipper transcription factor essential for normal and malignant hematopoiesis. In T-cell acute lymphoblastic leukemia (T-ALL), elevated MYB levels can arise directly through T-cell receptor-mediated MYB translocations, genomic MYB duplications or enhanced TAL1 complex binding at the MYB locus or indirectly through the TAL1/miR-223/FBXW7 regulatory axis. In this study, we used an unbiased MYB 3'untranslated region-microRNA (miRNA) library screen and identified 33 putative MYB-targeting miRNAs. Subsequently, transcriptome data from two independent T-ALL cohorts and different subsets of normal T-cells were used to select miRNAs with relevance in the context of normal and malignant T-cell transformation. Hereby, miR-193b-3p was identified as a novel bona fide tumor-suppressor miRNA that targets MYB during malignant T-cell transformation thereby offering an entry point for efficient MYB targeting-oriented therapies for human T-ALL.

Determining differentially expressed miRNAs and validating miRNA--target relationships using the SPRET/Ei mouse strain.

Micro RNAs (miRs) are involved in many biological processes. The challenge of identifying genes influenced by miRs is evidenced by the relatively few validated miR-target interactions. In this work, we used the Mus spretus SPRET/Ei strain as an in vivo system to identify new miR-target relations. Mus spretus diverged from Mus musculus over one million years ago, making it genetically and phenotypically divergent. SPRET/Ei mice are resistant to inflammation and several cancers, making them attractive for different research fields. Their phenotype is unique and is considerably different from that of almost all other laboratory mouse strains. We exploited the characteristics of SPRET/Ei mice as a tool to identify miR-target relationships. Hepatic genes and miRs differentially expressed between C57BL/6 and SPRET/Ei mice at basal levels were identified with an Affymetrix microarray and a multiplex qPCR, respectively. A total of 955 genes and 38 miRs were identified as differentially expressed. Increased miR expression might result in downregulation of its target mRNA and vice versa. Subsequently, we used our miR and mRNA data to identify possible in vivo miR-target interactions. Ingenuity pathway analysis (IPA) analysis revealed 380 possible miR-target interactions. Five miRs were selected for experimental validation by in vivo overexpression of the miRs. This resulted in the confirmation of six previously unknown miR-target interactions: miR-146a, Zdhhc2; miR-150, Elovl3, Kcnk5, and Nrd1d2; miR-155, Camta1; and miR-592, Steap2. In conclusion, we show that SPRET/Ei mice can be used as a platform for miR-target identification in vivo, and we used this platform to identify and experimentally confirm miR-target interactions.

DNA methylation silences miR-132 in prostate cancer.

Silencing of microRNAs (miRNAs) by promoter CpG island methylation may be an important mechanism in prostate carcinogenesis. To screen for epigenetically silenced miRNAs in prostate cancer (PCa), we treated prostate normal epithelial and carcinoma cells with 5-aza-2'-deoxycytidine (AZA) and subsequently examined expression changes of 650 miRNAs by megaplex stemloop reverse transcription-quantitative PCR. After applying a selection strategy, we analyzed the methylation status of CpG islands upstream to a subset of miRNAs by methylation-specific PCR. The CpG islands of miR-18b, miR-132, miR-34b/c, miR-148a, miR-450a and miR-542-3p showed methylation patterns congruent with their expression modulations in response to AZA. Methylation analysis of these CpG islands in a panel of 50 human prostate carcinoma specimens and 24 normal controls revealed miR-132 to be methylated in 42% of human cancer cases in a manner positively correlated to total Gleason score and tumor stage. Expression analysis of miR-132 in our tissue panel confirmed its downregulation in methylated tumors. Re-expression of miR-132 in PC3 cells induced cell detachment followed by cell death (anoikis). Two pro-survival proteins-heparin-binding epidermal growth factor and TALIN2-were confirmed as direct targets of miR-132. The results of this study point to miR-132 as a methylation-silenced miRNA with an antimetastatic role in PCa controlling cellular adhesion.

Modulation of neuroblastoma disease pathogenesis by an extensive network of epigenetically regulated microRNAs.

MicroRNAs (miRNAs) contribute to the pathogenesis of many forms of cancer, including the pediatric cancer neuroblastoma, but the underlying mechanisms leading to altered miRNA expression are often unknown. Here, a novel integrated approach for analyzing DNA methylation coupled with miRNA and mRNA expression data sets identified 67 epigenetically regulated miRNA in neuroblastoma. A large proportion (42%) of these miRNAs was associated with poor patient survival when underexpressed in tumors. Moreover, we demonstrate that this panel of epigenetically silenced miRNAs targets a large set of genes that are overexpressed in tumors from patients with poor survival in a highly redundant manner. The genes targeted by the epigenetically regulated miRNAs are enriched for a number of biological processes, including regulation of cell differentiation. Functional studies involving ectopic overexpression of several of the epigenetically silenced miRNAs had a negative impact on neuroblastoma cell viability, providing further support to the concept that inactivation of these miRNAs is important for neuroblastoma disease pathogenesis. One locus, miR-340, induced either differentiation or apoptosis in a cell context dependent manner, indicating a tumor suppressive function for this miRNA. Intriguingly, it was determined that miR-340 is upregulated by demethylation of an upstream genomic region that occurs during the process of neuroblastoma cell differentiation induced by all-trans retinoic acid (ATRA). Further biological studies of miR-340 revealed that it directly represses the SOX2 transcription factor by targeting of its 3'-untranslated region, explaining the mechanism by which SOX2 is downregulated by ATRA. Although SOX2 contributes to the maintenance of stem cells in an undifferentiated state, we demonstrate that miR-340-mediated downregulation of SOX2 is not required for ATRA induced differentiation to occur. In summary, our results exemplify the dynamic nature of the miRNA epigenome and identify a remarkable network of miRNA/mRNA interactions that significantly contribute to neuroblastoma disease pathogenesis.

Lysine-specific demethylase 1 restricts hematopoietic progenitor proliferation and is essential for terminal differentiation.

Lysine (K)-specific demethylase 1A (LSD1/KDM1A) has been identified as a potential therapeutic target in solid cancers and more recently in acute myeloid leukemia. However, the potential side effects of a LSD1-inhibitory therapy remain elusive. Here, we show, with a newly established conditional in vivo knockdown model, that LSD1 represents a central regulator of hematopoietic stem and progenitor cells. LSD1 knockdown (LSD1-kd) expanded progenitor numbers by enhancing their proliferative behavior. LSD1-kd led to an extensive expansion of granulomonocytic, erythroid and megakaryocytic progenitors. In contrast, terminal granulopoiesis, erythropoiesis and platelet production were severely inhibited. The only exception was monopoiesis, which was promoted by LSD1 deficiency. Importantly, we showed that peripheral blood granulocytopenia, monocytosis, anemia and thrombocytopenia were reversible after LSD1-kd termination. Extramedullary splenic hematopoiesis contributed to the phenotypic reversion, and progenitor populations remained expanded. LSD1-kd was associated with the upregulation of key hematopoietic genes, including Gfi1b, Hoxa9 and Meis1, which are known regulators of the HSC/progenitor compartment. We also demonstrated that LSD1-kd abrogated Gfi1b-negative autoregulation by crossing LSD1-kd with Gfi1b:GFP mice. Taken together, our findings distinguish LSD1 as a critical regulator of hematopoiesis and point to severe, but reversible, side effects of a LSD1-targeted therapy.

Hsa-mir-145 is the top EWS-FLI1-repressed microRNA involved in a positive feedback loop in Ewing's sarcoma.

EWS-FLI1 is a chromosome translocation-derived chimeric transcription factor that has a central and rate-limiting role in the pathogenesis of Ewing's sarcoma. Although the EWS-FLI1 transcriptomic signature has been extensively characterized on the mRNA level, information on its impact on non-coding RNA expression is lacking. We have performed a genome-wide analysis of microRNAs affected by RNAi-mediated silencing of EWS-FLI1 in Ewing's sarcoma cell lines, and differentially expressed between primary Ewing's sarcoma and mesenchymal progenitor cells. Here, we report on the identification of hsa-mir-145 as the top EWS-FLI1-repressed microRNA. Upon knockdown of EWS-FLI1, hsa-mir-145 expression dramatically increases in all Ewing's sarcoma cell lines tested. Vice versa, ectopic expression of the microRNA in Ewing's sarcoma cell lines strongly reduced EWS-FLI1 protein, whereas transfection of an anti-mir to hsa-mir-145 increased the EWS-FLI1 levels. Reporter gene assays revealed that this modulation of EWS-FLI1 protein was mediated by the microRNA targeting the FLI1 3'-untranslated region. Mutual regulations of EWS-FLI1 and hsa-mir-145 were mirrored by an inverse correlation between their expression levels in four of the Ewing's sarcoma cell lines tested. Consistent with the role of EWS-FLI1 in Ewing's sarcoma growth regulation, forced hsa-mir-145 expression halted Ewing's sarcoma cell line growth. These results identify feedback regulation between EWS-FLI1 and hsa-mir-145 as an important component of the EWS-FLI1-mediated Ewing's sarcomagenesis that may open a new avenue to future microRNA-mediated therapy of this devastating malignant disease.

MicroRNA miR-885-5p targets CDK2 and MCM5, activates p53 and inhibits proliferation and survival.

Several microRNA (miRNA) loci are found within genomic regions frequently deleted in primary neuroblastoma, including miR-885-5p at 3p25.3. In this study, we demonstrate that miR-885-5p is downregulated on loss of 3p25.3 region in neuroblastoma. Experimentally enforced miR-885-5p expression in neuroblastoma cell lines inhibits proliferation triggering cell cycle arrest, senescence and/or apoptosis. miR-885-5p leads to the accumulation of p53 protein and activates the p53 pathway, resulting in upregulation of p53 targets. Enforced miR-885-5p expression consistently leads to downregulation of cyclin-dependent kinase (CDK2) and mini-chromosome maintenance protein (MCM5). Both genes are targeted by miR-885-5p via predicted binding sites within the 3'-untranslated regions (UTRs) of CDK2 and MCM5. Transcript profiling after miR-885-5p introduction in neuroblastoma cells reveals alterations in expression of multiple genes, including several p53 target genes and a number of factors involved in p53 pathway activity. Taken together, these data provide evidence that miR-885-5p has a tumor suppressive role in neuroblastoma interfering with cell cycle progression and cell survival.

An integrative genomics screen uncovers ncRNA T-UCR functions in neuroblastoma tumours.

Different classes of non-coding RNAs, including microRNAs, have recently been implicated in the process of tumourigenesis. In this study, we examined the expression and putative functions of a novel class of non-coding RNAs known as transcribed ultraconserved regions (T-UCRs) in neuroblastoma. Genome-wide expression profiling revealed correlations between specific T-UCR expression levels and important clinicogenetic parameters such as MYCN amplification status. A functional genomics approach based on the integration of multi-level transcriptome data was adapted to gain insights into T-UCR functions. Assignments of T-UCRs to cellular processes such as TP53 response, differentiation and proliferation were verified using various cellular model systems. For the first time, our results define a T-UCR expression landscape in neuroblastoma and suggest widespread T-UCR involvement in diverse cellular processes that are deregulated in the process of tumourigenesis.

MYCN/c-MYC-induced microRNAs repress coding gene networks associated with poor outcome in MYCN/c-MYC-activated tumors.

Increased activity of MYC protein-family members is a common feature in many cancers. Using neuroblastoma as a tumor model, we established a microRNA (miRNA) signature for activated MYCN/c-MYC signaling in two independent primary neuroblastoma tumor cohorts and provide evidence that c-MYC and MYCN have overlapping functions. On the basis of an integrated approach including miRNA and messenger RNA (mRNA) gene expression data we show that miRNA activation contributes to widespread mRNA repression, both in c-MYC- and MYCN-activated tumors. c-MYC/MYCN-induced miRNA activation was shown to be dependent on c-MYC/MYCN promoter binding as evidenced by chromatin immunoprecipitation. Finally, we show that pathways, repressed through c-MYC/MYCN miRNA activation, are highly correlated to tumor aggressiveness and are conserved across different tumor entities suggesting that c-MYC/MYCN activate a core set of miRNAs for cooperative repression of common transcriptional programs related to disease aggressiveness. Our results uncover a widespread correlation between miRNA activation and c-MYC/MYCN-mediated coding gene expression modulation and further substantiate the overlapping functions of c-MYC and MYCN in the process of tumorigenesis.

Monoallelic but not biallelic loss of Dicer1 promotes tumorigenesis in vivo.

Human tumors are characterized by widespread reduction in microRNA (miRNA) expression, although it is unclear how such changes come about and whether they have an etiological role in the disease. Importantly, miRNA knockdown has been shown to enhance the tumorigenic potential of human lung adenocarcinoma cells. A defect in miRNA processing is one possible mechanism for global downregulation. To explore this possibility in more detail in vivo, we have manipulated Dicer1 gene dosage in a mouse model of retinoblastoma. We show that although monoallelic loss of Dicer1 does not affect normal retinal development, it dramatically accelerates tumor formation on a retinoblastoma-sensitized background. Importantly, these tumors retain one wild-type Dicer1 allele and exhibit only a partial decrease in miRNA processing. Accordingly, in silico analysis of human cancer genome data reveals frequent hemizygous, but not homozygous, deletions of DICER1. Strikingly, complete loss of Dicer1 function in mice did not accelerate retinoblastoma formation. miRNA profiling of these tumors identified members of the let-7 and miR-34 families as candidate tumor suppressors in retinoblastoma. We conclude that Dicer1 functions as a haploinsufficient tumor suppressor. This finding has implications for cancer etiology and cancer therapy.

The female inferior hypogastric (= pelvic) plexus: anatomical and radiological description of the plexus and its afferences--applications to pelvic surgery.

AIM OF THE STUDY: We wanted to determine the anatomical features of the inferior hypogastric plexus (IHP), and the useful landmarks for a safe surgical approach during pelvic surgery. MATERIALS AND METHODS: We dissected the IHP in 22 formolized female anatomical subjects, none of which bore any stigmata of subumbilical surgery. RESULTS: The inferior hypogastric plexus (IHP) is a triangle with a posterior base and an anterior inferior top. It can be described as having three edges and three angles; its inferior edge stretches constantly from the fourth sacral root to the ureter's point of entry into the posterior layer of the broad ligament; its cranial edge is strictly parallel to the posterior edge of the hypogastric artery, along which it runs at a distance of 10 mm; its posterior (dorsal) edge is at the point of contact with the sacral roots, from which it receives its afferences. They most frequently originate from S3 or S4 (60%) and then, in one or two branches, often from S2 (40%), never from S1 and in exceptional cases from S5 (20%). There are sympathetic afferences in 30% of cases, usually through a single branch of the second, third or fourth sacral ganglion. All IHPs have at least one sacral afference and sometimes there may be up to three afferences from the same sacral root. Its dorsal cranial angle, which is superior, comes after the SHP (hypogastric nerve or presacral nerve filament); its anterior inferior angle is located exactly at the ureter's point of entry into the posterior layer of the broad ligament. This is the top of the IHP; its posterior inferior angle is located at the point of contact with the fourth sacral root. At its entrance at the base of the parametrium the pelvic ureter is the anterior, fundamental positional reference for the IHP. The vaginal efferences come out of the top of the IHP through branches leading to the bladder, the vagina and the rectum, which originate through two trunks exactly underneath the crossing point of the ureter and the uterine artery: (i) one trunk leading to the bladder runs along and underneath the ureter and divides into two groups, which are lateral and medial, trigonal. (ii) the trunk leading to the vagina runs along the inferior edge of the uterine artery. At the point of contact with the lateral edge of the vagina, it splits into two groups: anterior thin and posterior voluminous. Some of its branches perforate the posterior wall of the vagina and are distributed to the rectovaginal septum in a tooth comb pattern. The inferior branches, which emerge from the inferior edge of the IHP, reach the rectum directly. The dissection of the 22 specimens allowed us to describe three efferent plexuses: a vaginal rectal plexus, a vesical plexus and a inferior rectal plexus. So the IHP's anterior, fundamental positional reference is the pelvic ureter at the point where it enters at the base of the parametrium, then at the crossing point of the uterine artery. The ureter is the vector for vesical efferences, the uterine artery is the vector for vaginal efferences, which are thus sent into the vesicovaginal septum and the rectovaginal septum. This surgical point of reference is of vital importance in nerve sparing during the course of a simple or extended hysterectomy. Any dissection carried out underneath and outside of the ureter inevitably carries a risk of lesions to its efferent, lateral vesical or medial, rectovaginal fibres.

[Dynamic MRI in the assessment of surgical results in genital prolapse: report of a case]. / L'IRM dynamique dans l'évaluation des résultats de la chirurgie du prolapsus génital: à propos d'une observation.

We wish to discuss the importance of MRI in association with the clinical pelvic examination for the study of vaginal prolapse, especially for the posterior compartment (rectocele, elytrocele). The increased sensitivity of static and dynamic MRI allowed a clinico-radiology relation more exactly for the study of prolapse. We describe a clinical observation where the RMI used before and after surgery is more reliable than the only clinic examination.

[Fetal thoracic MR imaging]. / IRM thoracique foetale.

Ultrasonography is the method of choice for prenatal malformation screening, but it does not always provide sufficient informations to allow a correct diagnosis or an adequate abnormality evaluation. Fetal MRImaging (MRI) indications are increasing in order to complete sonographic findings. It has been initially used for evaluation of cerebral abnormalities, but it is more and more applied to other fetal areas. An adequate analysis of fetal chest and abdomen can be obtained with fast T2 and T1 weighted sequences. This allows an easy diagnosis of congenital diaphragmatic hernia and an evaluation of the consequences on pulmonary growth. Other pulmonary malformations can be also easily identified (cystic adenoid malformation, sequestration, bronchogenic cyst, tracheal or bronchial atresia). Therefore, fetal thoracic MRI contributes to a better understanding and evaluation of fetal thoracic malformations, which is particularly useful for their postnatal management.

[MRI in gynecology]. / IRM en gynécologie.

OBJECTIVES: To review the complementary role and contribution of magnetic resonance imaging (MRI) in gynecology diseases. RESULTS: Tissue characterization can be obtained with T2, T1 weighted images before and after contrast medium injection and T1 fat sat sequences. Localization of the lesion and relationships with adjacent structures are facilitated by multiplanar imaging. Endometrium and ovarian follicles display high signal intensity, visualizing the normal uterine and ovarian components. The relative high signal intensity of uterine tumors facilitates evaluation of extension. Uterine leiomyoma diagnosis is supported by its low signal intensity, allowing localization, size, and number assessment, and to distinguish adenomyoma. In doubtful malformation cases, MRI may be contributive. Ovarian mass characterization can be done with MRI, particularly for dermoid cyst and endometrioma. In this case, deep endometriosis can be associated and be extensive. Recent technical advances enable fast imaging, which can be useful for pelvic floor assessment with dynamic evaluation. CONCLUSION: MRI is becoming the complementary reference imaging tool for us. Its increasing indications are: gynecologic cancer, pelvis endometriosis, pelvis floor, indeterminate pelvis mass and fibroleiomyoma.

[Imaging of the endometrium]. / Imagerie de l'endomètre.

During genital activity, physiological and pathological modifications can be observed; Pre- and postmenopausal menometror-rhagia are the principle clinical signs of various endometrial pathologies: benign (polyp, atrophy or endometrial hypertrophy), malignant (cervical or endometrial carcinoma) or neighboring pathologies (myometrium or ovary). The value and methods of various imaging techniques (B-mode and Doppler abdominal and endovaginal ultrasonography, hysterosonography, computed tomography, MR imaging and hysteroscopy) are described together with symptomatological features permitting identification of the endometrial pathology.

[Ovarian functional disorders]. / Pathologie fonctionnelle de l'ovaire.

Ovarian hormonal function is under hypothalamo-hypophysis control during the genital life of women. Local hormonal production induces follicular stimulation and maturation. Two main types of functional disorder can be observed: unilocular cyst, related to an ovulation mechanism, and polycystic ovaries. The former is a follicular cyst related to the absence of LH stimulation, or a luteal cyst, which may be anechoic or display a heterogeneous content (pseudo-septa, pseudo-solid but avascular mass). The latter includes the polycystic ovarian syndrome, which is characterized by an increased ovarian area ( 6cm(2)), stroma and follicles number, the multifollicular ovaries, which are related to functional hypothalamic anovulation and characterized by a normal ovarian size with increased follicles number, and macropolycystic ovaries which are observed in case of previous pelvic infection disease or surgery. Functional disorders may be observed during pregnancy: luteoma, luteal cyst and hyperreactio luteinalis. Finally, ovarian insufficiency may occur too early.