Nicolas Tremblay

Dr. Nicolas Tremblay

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Research Focus & Metrics

Academic Career Length

28Years (1999-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 December 2015 in Journal of Clinical Microbiology
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CCCaroline Chartrand
Caroline Chartrand
NTNicolas Tremblay
Nicolas Tremblay
CRChristian Renaud
Christian Renaud
JPJesse Papenburg
Jesse Papenburg
Respiratory syncytial virus (RSV) rapid antigen detection tests (RADT) are extensively used in clinical laboratories. We performed a systematic review and meta-analysis to evaluate the accuracy of RADTs for diagnosis of RSV infection and to determine factors associated with accuracy estimates. We searched EMBASE and PubMed for diagnostic-accuracy studies of commercialized RSV RADTs. Studies reporting sensitivity and specificity data compared to a reference standard (reverse transcriptase PCR [RT-PCR], immunofluorescence, or viral culture) were considered. Two reviewers independently extracted data on study characteristics, diagnostic-accuracy estimates, and study quality. Accuracy estimates were pooled using bivariate random-effects regression models. Heterogeneity was investigated with prespecified subgroup analyses. Seventy-one articles met inclusion criteria. Overall, RSV RADT pooled sensitivity and specificity were 80% (95% confidence interval [CI], 76% to 83%) and 97% (95% CI, 96% to 98%), respectively. Positive- and negative-likelihood ratios were 25.5 (95% CI, 18.3 to 35.5) and 0.21 (95% CI, 0.18 to 0.24), respectively. Sensitivity was higher in children (81% [95% CI, 78%, 84%]) than in adults (29% [95% CI, 11% to 48%]). Because of this disparity, further subgroup analyses were restricted to pediatric data (63 studies). Test sensitivity was poorest using RT-PCR as a reference standard and highest using immunofluorescence (74% versus 88%; P < 0.001). Industry-sponsored studies reported significantly higher sensitivity (87% versus 78%; P = 0.01). Our results suggest that the poor sensitivity of RSV RADTs in adults may preclude their use in this population. Furthermore, industry-sponsored studies and those that did not use RT-PCR as a reference standard likely overestimated test sensitivity.

1 July 1999 in Molecular Ecology
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Journal Article
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NTNicolas Tremblay
Nicolas Tremblay
DSD. J. Schoen
D. J. Schoen
Chloroplast DNA variation in the Arctic plant speciesDryas integrifolia(Rosaceae) was analysed in relation to both the present‐day geographical distribution of populations and to Pleistocene fossil records of this species. The phylogeographical structure was weak but the analysis of haplotype diversity revealed several groups of haplotypes having present‐day geographical ranges that overlap locations postulated from geographical and fossil evidence to have been glacial refugia. Based on this information we infer that two important refugial sources of Arctic recolonization by this species were Beringia and the High Arctic. Two other putative refugia, located southeast of the ice sheet and along coastal regions of the eastern Arctic may have served as sources for recolonization of smaller portions of the Arctic. The genetic substructure in the species is mostly due to variation among populations regardless of the ecogeographical region in which they are found. Spatial autocorrelation at the regional scale was also detected. High levels of diversity both within populations and ecogeographical regions are probably indicative of population establishment from several sources possibly combined with recent gene flow.

30 April 2018 in Journal of Immunology Research
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Elias A. SaidElias A. Said
Elias A. Said
NTNicolas Tremblay
Nicolas Tremblay
MAMohammed S. Al-Balushi
Mohammed S. Al-Balushi
AAAli Al-Jabri
Ali Al-Jabri
DLDaniel Lamarre
Daniel Lamarre
The role of the innate immune response in detecting RNA viruses is crucial for the establishment of proper inflammatory and antiviral responses. Different receptors, known as pattern recognition receptors (PRRs), are present in the cytoplasm, endosomes, and on the cellular surface. These receptors have the capacity to sense the presence of viral nucleic acids as pathogen-associated molecular patterns (PAMPs). This recognition leads to the induction of type 1 interferons (IFNs) as well as inflammatory cytokines and chemokines. In this review, we provide an overview of the significant involvement of cellular RNA helicases and Toll-like receptors (TLRs) 3, 7, and 8 in antiviral immune defenses.

2 May 2017 in Traffic
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BGBridget Gagné
Bridget Gagné
NTNicolas Tremblay
Nicolas Tremblay
APAlex Y. Park
Alex Y. Park
MBMartin Baril
Martin Baril
DLDaniel Lamarre
Daniel Lamarre

10 October 2019 in Vaccines
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NTNicolas Tremblay
Nicolas Tremblay
WFwesley freppel
wesley freppel
ASAïssatou Aïcha Sow
Aïssatou Aïcha Sow
LCLaurent Chatel-Chaix
Laurent Chatel-Chaix
With 40% of the world population at risk, infections with dengue virus (DENV) constitute a serious threat to public health. While there is no antiviral therapy available against this potentially lethal disease, the efficacy of the only approved vaccine is not optimal and its safety has been recently questioned. In order to develop better vaccines based on attenuated and/or chimeric viruses, one must consider how the human immune system is engaged during DENV infection. The activation of the innate immunity through the detection of viruses by cellular sensors is the first line of defence against those pathogens. This triggers a cascade of events which establishes an antiviral state at the cell level and leads to a global immunological response. However, DENV has evolved to interfere with the innate immune signalling at multiple levels, hence dampening antiviral responses and favouring viral replication and dissemination. This review elaborates on the interplay between DENV and the innate immune system. A special focus is given on the viral countermeasure mechanisms reported over the last decade which should be taken into consideration during vaccine development.

11 January 2021 in Cellular Microbiology
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AAAnais Anton
Anais Anton
CMClément Mazeaud
Clément Mazeaud
WFwesley freppel
wesley freppel
CGClaudia Gilbert
Claudia Gilbert
NTNicolas Tremblay
Nicolas Tremblay
LCLaurent Chatel-Chaix
Laurent Chatel-Chaix
With no available therapies, infections with Zika virus (ZIKV) constitute a major public health concern as they can lead to congenital microcephaly. In order to generate an intracellular environment favourable to viral replication, ZIKV induces endomembrane remodelling and the morphogenesis of replication factories via enigmatic mechanisms. In this study, we identified the AAA+ type ATPase valosin‐containing protein (VCP) as a cellular interaction partner of ZIKV non‐structural protein 4B (NS4B). Importantly, its pharmacological inhibition as well as the expression of a VCP dominant‐negative mutant impaired ZIKV replication. In infected cells, VCP is relocalised to large ultrastructures containing both NS4B and NS3, which are reminiscent of dengue virus convoluted membranes. Moreover, short treatment with the VCP inhibitors NMS‐873 or CB‐5083 drastically decreased the abundance and size of ZIKV‐induced convoluted membranes. Furthermore, NMS‐873 treatment inhibited ZIKV‐induced mitochondria elongation previously reported to be physically and functionally linked to convoluted membranes in case of the closely related dengue virus. Finally, VCP inhibition resulted in enhanced apoptosis of ZIKV‐infected cells strongly suggesting that convoluted membranes limit virus‐induced cytopathic effects. Altogether, this study identifies VCP as a host factor required for ZIKV life cycle and more precisely, for the maintenance of viral replication factories. Our data further support a model in which convoluted membranes regulate ZIKV life cycle by impacting on mitochondrial functions and ZIKV‐induced death signals in order to create a cytoplasmic environment favourable to viral replication.