Transcatheter tricuspid valve implantation: A multicentre French study

SummaryBackgroundTranscatheter valve-in-valve (VIV) implantation in failing bioprosthesis is an emerging field in cardiology.AimTo report on a French multicentre experience and a literature review of tricuspid VIV implantation.MethodsWe approached different institutions and collected 10 unpublished cases; a literature review identified 71 patients, including our 10 cases. Clinical aspects and haemodynamic data are discussed.ResultsAmong our 10 unpublished cases, the reason for implantation was significant tricuspid stenosis (n=4), significant tricuspid regurgitation (n=1) or mixed lesion (n=5). Implantation was performed under general anaesthesia at mean age 28±17 years. The 22mm Melody valve was implanted in seven patients; the Edwards SAPIEN valve was implanted in three patients. The procedure succeeded in all cases, despite two embolizations in the right cardiac chambers; in both cases, the valve was stabilized close to the tricuspid annulus using a self-expandable stent, before implantation of a second Edwards SAPIEN valve. Functional class improved in all but one case. Mean diastolic gradient decreased from 9±2.45mmHg to 3.65±0.7mmHg (p=0.007); no more than trivial regurgitation was noticed. Among the published cases, the Melody valve was implanted in 41 patients, the Edwards SAPIEN valve in 29 patients and the Braile valve in one patient. Short-term results were similar for our 10 cases, but mid-term results are not yet available.ConclusionsTricuspid VIV implantation using the Melody or Edwards SAPIEN valves is a feasible and effective procedure for selected patients with failing bioprosthesis

Strong protection induced by an experimental DIVA subunit vaccine against bluetongue virus serotype 8 in cattle

AbstractBluetongue virus (BTV) infections in ruminants pose a permanent agricultural threat since new serotypes are constantly emerging in new locations. Clinical disease is mainly observed in sheep, but cattle were unusually affected during an outbreak of BTV seroype 8 (BTV-8) in Europe. We previously developed an experimental vaccine based on recombinant viral protein 2 (VP2) of BTV-8 and non-structural proteins 1 (NS1) and NS2 of BTV-2, mixed with an immunostimulating complex (ISCOM)–matrix adjuvant. We demonstrated that bovine immune responses induced by this vaccine were as good or superior to those induced by a classic commercial inactivated vaccine. In this study, we evaluated the protective efficacy of the experimental vaccine in cattle and, based on the detection of VP7 antibodies, assessed its DIVA compliancy following virus challenge. Two groups of BTV-seronegative calves were subcutaneously immunized twice at a 3-week interval with the subunit vaccine (n=6) or with adjuvant alone (n=6). Following BTV-8 challenge 3 weeks after second immunization, controls developed viremia and fever associated with other mild clinical signs of bluetongue disease, whereas vaccinated animals were clinically and virologically protected. The vaccine-induced protection was likely mediated by high virus-neutralizing antibody titers directed against VP2 and perhaps by cellular responses to NS1 and NS2. T lymphocyte responses were cross-reactive between BTV-2 and BTV-8, suggesting that NS1 and NS2 may provide the basis of an adaptable vaccine that can be varied by using VP2 of different serotypes. The detection of different levels of VP7 antibodies in vaccinated animals and controls after challenge suggested a compliancy between the vaccine and the DIVA companion test. This BTV subunit vaccine is a promising candidate that should be further evaluated and developed to protect against different serotypes

Etude du mecanisme d'action d'agents antitumoraux : mise en evidence du role des ADN-topoisomerases 2 et de leur interaction avec l'oncogene c-myc

SIGLECNRS T 59502 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

A closed max-t test for multiple comparisons of areas under the ROC curve

Comparing areas under the ROC curve (AUCs) is a popular approach to compare prognostic biomarkers. The aim of this paper is to present an efficient method to control the family-wise error rate when multiple comparisons are performed. We suggest to combine the max-t test and the closed testing procedures. We build on previous work on asymptotic results for ROC curves and on general multiple testing methods to efficiently take into account both the correlations between the test statistics and the logical constraints between the null hypotheses. The proposed method results in an uniformly more powerful procedure than both the single-step max-t test procedure and popular stepwise extensions of the Bonferroni procedure, such as Bonferroni-Holm. As demonstrated in this paper, the method can be applied in most usual contexts, including the time-dependent context with right censored data. We show how the method works in practice through a motivating example where we compare several psychometric scores to predict the t-year risk of Alzheimer's disease. The example illustrates several multiple testing settings and demonstrates the advantage of using the proposed methods over common alternatives. R code has been made available to facilitate the use of the methods by others

AP-TSS: A New Method for the Analysis of RNA Expression from Particular and Challenging Transcription Start Sites

Alternative promoter usage involved in the regulation of transcription, splicing, and translation contributes to proteome diversity and is involved in a large number of diseases, in particular, cancer. Epigenetic mechanisms and cis regulatory elements are involved in alternative promoter activity. Multiple transcript isoforms can be produced from a gene, due to the initiation of transcription at different transcription start sites (TSS). These transcripts may not have regions that allow discrimination during RT-qPCR, making quantification technically challenging. This study presents a general method for the relative quantification of a transcript synthesized from a particular TSS that we called AP-TSS (analysis of particular TSS). AP-TSS is based on the specific elongation of the cDNA of interest, followed by its quantification by qPCR. As proof of principle, AP-TSS was applied to two non-coding RNA: telomeric repeat-containing RNAs (TERRA) from a particular subtelomeric TSS, and Alu transcripts. The treatment of cells with a DNA methylation inhibitor was associated with a global increase of the total TERRA level, but the TERRA expression from the TSS of interest did not change in HT1080 cells, and only modestly increased in HeLa cells. This result suggests that TERRA upregulation induced by global demethylation of the genome is mainly due to activation from sites other than this particular TSS. For Alu RNA, the signal obtained by AP-TSS is specific for the RNA Polymerase III-dependent Alu transcript. In summary, our method provides a tool to study regulation of gene expression from a given transcription start site, in different conditions that could be applied to many genes. In particular, AP-TSS can be used to investigate the epigenetic regulation of alternative TSS usage that is of importance for the development of epigenetic-targeted therapies

Repression of TERRA Expression by Subtelomeric DNA Methylation Is Dependent on NRF1 Binding

International audienceChromosome ends are transcribed into long noncoding telomeric repeat-containing RNA (TERRA) from subtelomeric promoters. A class of TERRA promoters are associated with CpG islands embedded in repetitive DNA tracts. Cytosines in these subtelomeric CpG islands are frequently methylated in telomerase-positive cancer cells, and demethylation induced by depletion of DNA methyltransferases is associated with increased TERRA levels. However, the direct evidence and the underlying mechanism regulating TERRA expression through subtelomeric CpG islands methylation are still to establish. To analyze TERRA regulation by subtelomeric DNA methylation in human cell line (HeLa), we used an epigenetic engineering tool based on CRISPR-dCas9 (clustered regularly interspaced short palindromic repeats - dead CRISPR associated protein 9) associated with TET1 (ten-eleven 1 hydroxylase) to specifically demethylate subtelomeric CpG islands. This targeted demethylation caused an up-regulation of TERRA, and the enhanced TERRA production depended on the methyl-sensitive transcription factor NRF1 (nuclear respiratory factor 1). Since AMPK (AMP-activated protein kinase) is a well-known activator of NRF1, we treated cells with an AMPK inhibitor (compound C). Surprisingly, compound C treatment increased TERRA levels but did not inhibit AMPK activity in these experimental conditions. Altogether, our results provide new insight in the fine-tuning of TERRA at specific subtelomeric promoters and could allow identifying new regulators of TERRA

Characterization of potential TRPP2 regulating proteins in early Xenopus embryos

International audienceTransient receptor potential cation channel‐2 (TRPP2) is a nonspecific Ca2+‐dependent cation channel with versatile functions including control of extracellular calcium entry at the plasma membrane, release of intracellular calcium ([Ca2+]i) from internal stores of endoplasmic reticulum, and calcium‐dependent mechanosensation in the primary cilium. In early Xenopus embryos, TRPP2 is expressed in cilia of the gastrocoel roof plate (GRP) involved in the establishment of left‐right asymmetry, and in nonciliated kidney field (KF) cells, where it plays a central role in early specification of nephron tubule cells dependent on [Ca2+]i signaling. Identification of proteins binding to TRPP2 in embryo cells can provide interesting clues about the mechanisms involved in its regulation during these various processes. Using mass spectrometry, we have therefore characterized proteins from late gastrula/early neurula stage embryos coimmunoprecipitating with TRPP2. Binding of three of these proteins, golgin A2, protein kinase‐D1, and disheveled‐2 has been confirmed by immunoblotting analysis of TRPP2‐coprecipitated proteins. Expression analysis of the genes, respectively, encoding these proteins, golga2, prkd1, and dvl2 indicates that they are likely to play a role in these two regions. Golga2 and prkd1 are expressed at later stage in the developing pronephric tubule where golgin A2 and protein kinase‐D1 might also interact with TRPP2. Colocalization experiments using exogenously expressed fluorescent versions of TRPP2 and dvl2 in GRP and KF reveal that these two proteins are generally not coexpressed, and only colocalized in discrete region of cells. This was observed in KF cells, but does not appear to occur in the apical ciliated region of GRP cells

Bisquinolinium compounds induce quadruplex-specific transcriptome changes in HeLa S3 cell lines.

International audienceABSTRACT: BACKGROUND: Guanosine rich sequences capable of forming G-quadruplex (G4) motifs are enriched near the gene transcription start site (TSS) in the human genome. When probed at the single gene level, G-quadruplex motifs residing in promoter regions show substantial effects on gene transcription. Moreover, further changes in transcription levels are noticed when G4-motifs are targeted with G-quadruplex-specific small molecules. RESULTS: Global studies concerning general changes of the transcriptome via targeting promoter-based G-quadruplex motifs are very limited and have so far only been carried out with compounds displaying weak selectivity for quadruplex sequences. Here we utilize two G-quadruplex-specific bisquinolinium derivatives PhenDC3 and 360A and investigate their effects on the expression of the HeLa S3 transcriptome. Our results show wide-spread changes in the transcriptome with specificity for genes with G-quadruplex motifs near their transcription start sites (TSS). Using real-time PCR we further confirmed the specificity of PhenDC3 and 360A as potent molecules to target G-quadruplex-regulated genes. CONCLUSIONS: Specific effects on quadruplex-containing genes have been observed utilizing whole-transcriptome analysis upon treatment of cultured cells with quadruplex-selective bisquinolinium compounds