NCube/papyrus huggingface dataset:
Coexistence cirrhose biliaire primitive et sclérodermie systémique : étude avec capillaroscopie et immunologie

Objective : To determine the prevalence of systemic scleroderma (SSc) in patients with primary biliary cirrhosis (PBC) and to describe the clinical, prognostic, immunologic and nailfold capillaropscopy characteristics in patients with and without SSc.  Study design : In this descriptive cohort study, 100 patients with PBC who were unknown for any connective tissue disease, in particular for SSc, were referred by their gastroenterologist. Physical examination with collection of serum samples and nailfold capillaroscopy examination were performed.  Results : Twenty-two patients had been diagnosed with SSc of which 13 had no  cutaneous manifestations of scleroderma.  Thirty-Nine patients had Raynaud’s phenomenon. Of the 19 patients with anticentromères antibodies (ACAs), 18 had SSc. Patients with PBC and SSc had a better Mayo score and less severe liver damage. Twenty-nine patients had abnormal nailfold capillaroscopy. More frequent portal hypertension 14/81 (17,28%, p= 0,876) and severe liver tissue damage (89.5%, p=0.125) seen in patients with positive ACAs. Mayo score was better in patients with positives ACAs. The sensitivity and specificity of the immunologic tests were 95,45% and 93,59% respectively. The sensitivity of nailfold capillaroscopy was 78% and specificity was 94% for the diagnosis of SSc in patients with PBC.    Conclusion : SSc is more prevalent in PBC. This study highlights the importance of screening for subtle clinical signs of SSc in patients with PBC, in particular Raynaud’s phenomenon, hence requiring immunologic tests and nailfold capillaroscopy to diagnose scleroderma at earlier stages.

Keyphrases: Immunologie, Primary biliary cirrhosis, Scleroderma, Immunology, Nailfold capillaropscopy, Reynolds syndrome
Évaluation de la relation entre la fibrose des tissus adipeux et la résistance à l’insuline chez l’humain obèse, avant et après chirurgie bariatrique

Obesity is associated to the development of metabolic complications, including insulin resistance. Yet, a distinctive subset of obese patients seems protected from insulin resistance. Such insulin-sensitive obese subpopulation (ISO) offers a unique opportunity to investigate factors underlying the development of insulin resistance in humans without the confounding effect of major differences in adiposity. Adipose tissue fibrosis has been directly linked to the development of obesity-associated insulin resistance in rodents. Therefore, we quantified total fibrosis and examined the expression of fibrosis-related genes in subcutaneous (SAT) and visceral (VAT) adipose tissue biopsies of diabetic (T2D) and non diabetic obese patients stratified into ISO or insulin-resistant obese (IRO) based on the OGTT-derived ISIMatsuda index, before and six months after bariatric surgery. Despite similar age, BMI, and percent fat mass, ISO had lower insulin resistance than IRO subjects (p<0.05) at baseline. No difference was found between ISO, IRO and T2D, neither in terms of total fibrosis, nor in the expression of fibrosis-related genes in the adipose tissues before surgery. However, log SAT fibrosis positively correlated with log HOMA-IR at baseline (r = 0.3847, p < 0.05). Six months after surgery, fibrosis levels remained unchanged in SAT, but insulin resistance was significantly reduced in all groups, especially in T2D patients. No correlation was found between SAT fibrosis and HOMA-IR after surgery. These results show a significant, yet ephemeral association between SAT fibrosis and insulin resistance in obese humans.

Keyphrases: Obesity, Insulin resistance, Metabolically healthy obese (MHO), Adipose tissue, Fibrosis, Bariatric surgery
L'inhibition de la production d'AMPc est modulée différemment à court et long terme par l'internalisation du récepteur opioïde delta

Opioids are the most powerful analgesics but their prolonged use can cause the development of analgesic tolerance. The tolerance may be associated with the duration of response to cAMP. For this study, we used a biosensor based on Bioluminescence Resonnance Energy Transfer technology that provides measurements of cAMP levels as a function of real time. The aim of our study was to determine whether there is a correlation between the internalization profile of delta-opioid receptor (DOR) when stimulated by different ligands, with respect to the duration of signaling in the short-term (≤15 min) and long term (120 min). This evolution of the duration of cAMP inhibition is biphasic and is explained in part by the efficiency of ligands to promote Gαi activation and by the profile of internalization for each of the different ligands used in this study. For example, deltorphin II which displayed high efficiency to promote Gαi activation and internalization shows a more pronounced decline in cAMP response, unlike morphine which displayed low efficiency to promote Gαi activation, and a poor sequestration, displaying a minimal response decay of inhibition of cAMP. However, ligand ability to promote internalization of DOR does not explain the kinetic profile of a persistent inhibition of cAMP over a longer period of 120 min.

Keyphrases: Ligands, Delta opioid receptor, signaling, internalization, Tolerance, Ligands, Desensitization
Mechanism of Inducible Costimulator (ICOS)-mediated calcium signaling

The Inducible Costimulator (ICOS) is a receptor expressed on activated CD4 helper and CD8 cytotoxic T cells. It was previously shown that ICOS plays an important role in inducing acute graft versus host disease (GVHD) in murine models of allogeneic bone marrow transplantation (BMT). ICOS potentiates TCR-mediated phosphoinositide 3-kinase (PI3K) activation and intracellular calcium mobilization. In both CD4+ and CD8+ T cells, ICOS can potentiate TCR-mediated calcium flux in a PI3K-independent manner in vitro. However, the ICOS signal transduction pathway involved in GVHD remains unknown. Using a knockin strain of mice (termed ICOS-Y181F) in which T cells have selectively lost the ability to activate PI3K, we have recently shown that T cells can utilize PI3K-independent ICOS signaling pathways to induce GVHD. The mobilization of intracellular Ca2+ leads to the activation of NFAT, a key transcription factor regulating genes such as IFN-γ, one of the key T cell cytokines involved in GVHD. Therefore, we hypothesize that the intact pathogenic capacity of ICOS-Y181F T cells to induce GVHD relies on ICOSdependent, PI3K-independent calcium signaling. My goal is to identify the residue(s) responsible for this ICOS-mediated Ca2+ signaling and find the mechanism by which the receptor achieves its function. Through sitedirected mutagenesis and flow cytometric analysis of calcium fluxing capacities of mutant ICOS proteins, I identified a membrane proximal cluster of lysine residues that is essential in inducing ICOS-mediated Ca2+ signaling. I also provide evidence for the involvement of the Src family kinase Lck in ICOS-mediated Ca2+signaling. ICOS associates with Lck molecules, leading to the activation of PLCγ1, the key effector protein causing the release of Ca2+ from the intracellular pool. Taken together, our study is beginning to unravel a complexity in ICOS signaling, and implicates the ICOS-Lck-PLCγ1 axis in T cell calcium signaling and potentially the induction of GVHD. Further understanding of this pathway could prove beneficial in designing new strategies to prevent ICOS-related diseases such as GVHD.

Keyphrases: Immunologie, Icos, Cellule T, Costimulation, Calcium, Immunology, T cell, Costimulation, Coreceptor, Signaling, Calcium
Rôle du TLR2 dans l’hépatite fulminante induite par le virus de l’hépatite murine

This work investigates the innate immunity mechanisms involved in the Murine Hepatitis Virus type 3 (MHV-3) acute hepatitis disease model. In the goal of determining the role of the TLR2 receptor in aggravating the hepatitis disease, in vivo infections with the MHV-3 virus were performed on C57BL/6 mice or tlr2-/- gene knockout mice as well as in vitro infections of murine macrophages and hepatocytes with the MHV-3 and less virulent MHV-A59 serotypes. The levels of transcription and translation of different microbial sensors, type I interferons (IFN), cytokines and/or chemokines were measured by qRT-PCR and ELISA tests. Cells were treated with small interfering ARN (siRNA) for the TLR2 and/or CEACAM1a genes or treated with the different endocytosis inhibitors before infection. Our results reveal the stimulatory role of the TLR2 receptor on viral replication, production levels of the IL-6 and TNF-α cytokines and chemokines CXCL1, CXCL10 and CCL2. This study also reveals a new immune evasion mechanism via TLR2 in macrophages infected with MHV-3, but not with the lesser virulent MHV-A59 serotype. These different experiments have revealed a new role for the TLR2 receptor in viral infections wherein inflammatory responses are aggravated whilst shielding viral detection by other pathogens sensors of the innate immunity.

Keyphrases: MHV-3, TLR2, IL-6, TNF-α, macrophages, acute hepatitis, chemokines, hepatocytes, endocytosis, immune escape
Comparative costs and outcomes of traumatic brain injury from biking accidents with or without helmet use

Rationale: Establishing determinants of preventable disease and their societal costs are necessary in the context of publicly funded healthcare. With recent increases in Québec bicyclists, it is an opportune time to evaluate the impact of cycling traumatic brain injuries (TBI).  Objective: Compare demographic and medical characteristics and social costs of cycling TBIs according to helmet status. Methods: Retrospective study of 128 cyclists with TBI, from a trauma database, admitted to the Montreal University Health Center - Montreal General Hospital (MUHC-MGH) between 2007 and 2011. The independent variables were sociodemographic and clinical characteristics, as well as helmet status. The dependant variables were LOS, GOS-E, ISS, discharge destination, deaths and societal costs, using a bottom up costing approach. Results: The helmet group tended to be older, more educated, retired and married; from a medical perspective, they had reduced probabilities of severe TBIs on imaging, had shorter intensive care hospitalizations and less neurosurgeries. Median societal costs of TBI were significantly lower when a helmet was used. Conclusion: In this study, helmets seemed to confer protective effects against certain TBI complications and decreased median overall costs to society. Helmet promotion is recommended.

Keyphrases: Prognostic, Bicyclette, Traumatic brain injury, Costs, Outcome, Helmet, Bicycle, Cycling
Étude comparative des projections des neurones dopaminergiques chez deux espèces animales

One of the most studied pathways in the control of locomotion is the ascending dopaminergic pathway, because of its importance in some diseases affecting locomotor behaviour like Parkinson’s disease. The A9 and the A10 send dopaminergic inputs to the basal ganglia that in turn, project to the RLM, a region from the brainstem that controls the locomotion in vertebrate. Dopaminergic terminals in the RLM were discovered in the monkey. It seemed interesting to know where they come from and if they were conserved in the evolution of vertebrate species. This is why we investigated the existence of such projection in the lamprey and the newt. In this study we observed a descending dopaminergic pathway from the posterior tuberculum (PT; homologue to A9 and A10 of mammals) to the RLM that does not go through the basal ganglia first. This descending dopaminergic pathway was observed in both the lamprey and the newt, following injection of a retrograde tracer and immunohistochemical detection of either tyrosine TH or DA. The descending dopaminergic pathway seems to be conserved in the evolution of the animal species, although the relative importance of the ascending DA+ pathway seems to increase with evolution.

Keyphrases: Locomotion, Dopamine, Mesencephalic locomotor region, Mesencephalon, Brainstem, Basal ganglia, Posterior tuberculum, Ventral tegmental area, Substantia nigra pars compacta
Pro-inflammatory and angiogenic activities of VEGF and angiopoietins in murine sponge/Matrigel model

A deregulation in blood vessel formation and integrity can lead to a pathological state as seen in many ischemic diseases such as tumor growth, rheumatoid arthritis, psoriasis, retinopathies and atherosclerosis. Therefore, the possibility to modulate regional angiogenesis in patients suffering from ischemia is clinically relevant. One key feature in the induction of pathological angiogenesis is that inflammation precedes and accompanies the formation of neovessels as evidenced by increased vascular permeability and the recruitment of monocytes/macrophages and neutrophils. Along with other groups, we have previously shown that selected growth factors, namely vascular endothelial growth factor (VEGF) and angiopoietins (Ang1 and Ang2) can not only promote angiogenesis but can also induce inflammatory responses, including the synthesis/release of inflammatory mediators and neutrophil migration. The objectives of our study were to address how VEGF and angiopoietins are capable of promoting the formation of neovessels over time and to identify the presence of different inflammatory cells in this event. Sterilized polyvinyl alcohol (PVA) sponges soaked in growth factor-depleted Matrigel containing PBS, VEGF, Ang1 or Ang2 (200 ng/200 μl) were subcutaneously inserted into anesthetized C57/Bl6 mice. The sponges were then removed at day 4, 7, 14 or 21 post-procedure for histological, immunohistological (IHC) and flow cytometric analyses. The formation of neovessels was validated by Masson’s Trichrome staining and by IHC against endothelial cells (anti-CD31) and its maturation was elucidated by sequential IHC staining against endothelial cells and smooth muscle cells (anti-alpha-actin). Likewise, we performed IHC to characterize the recruitment of neutrophils (anti-MPO), and macrophages (anti-F4/80). To better delineate the presence of different leukocyte subsets recruited in the sponges, we utilized multicolor flow cytometry procedure on single cell preparation from the sponges. We observed that both VEGF and angiopoietins favors the recruitment of endothelial cells and the formation of new vessels more rapidly as compared to PBS. Once formed by day 7, these neovessels remain stable in number, do not undergo reorganization in their cross sectional area and mature through the recruitment and ensheathing of smooth muscle cells. In addition, the angiogenic microenvironment is comprised of inflammatory cells, mainly neutrophils, macrophages, and sparsly T and B cells. Hence, VEGF, Ang1 and Ang2 individually promote the formation and stabilisation of neovessels and the venue of inflammatory cells with different potency in a temporal dependant manner in a sponge/Matrigel model.

Keyphrases: VEGF, maturation, inflammation, macrophages, angiopoietins, angiogenesis, neutrophils
Évolution échocardiographique et prédicteurs de progression de la sténose valvulaire aortique

Introduction: The clinical use of biomarkers to predict the progression of aortic valve stenosis (AVS) is not yet validated. We want to evaluate potential predictors of the progression of degenerative AVS on tricuspid valve.  Methods: We identified 126 cases with AVS and ≥ 2 echocardiograms post-recruitment and 126 paired controls recruited by the Montreal Heart Institute’s Biobank. We collected clinical, echocardiographic and genetic base data and measured plasma biomarkers. The AVS evolution was established by the analysis of the serial echocardiograms and defined as the mean variation per year of the following parameters: maximal aortic transvalvular velocity, mean aortic transvalvular gradient (MATG), aortic valve area and indexed aortic valve area. We evaluated the association of clinical, echocardiographic and genetic (LPA rs10455872 polymorphism) data with the AVS progression and plasma biomarkers with the AVS presence and progression. Results: The mean follow-up was 2.4 years. According to multivariate analysis concerning the clinical/echocardiographic/ LPA rs10455872 data, a higher heart rate (for older patients and males), diabetes mellitus (for males) and a greater MATG in the first echocardiogram are associated to a faster AVS evolution. The presence of aortic regurgitation in the first echocardiogram is associated to a slower AVS evolution. The analysis of plasma biomarkers versus the AVS presence and progression is ongoing.  Conclusion: Our results indicate that a higher heart rate, diabetes mellitus, and a greater MATG are associated with faster AVS progression. The results of this study should contribute to a more personalized approach of the AVS follow-up and treatment.

Keyphrases: Aortic valve stenosis, Biomarkers, Heart rate, Diabetes mellitus, Mean aortic transvalvular gradient, Aortic regurgitation
Caractérisation biochimique et fonctionnelle du mutant T179N de l’aquaporine-2 humaine

Aquaporin-2 (AQP2) is the channel responsible for the final reabsorption of water in the collecting duct of the kidney. Basically, contained in internal vesicles, the AQP2 is delivered to the apical membrane of the principal cells of the collecting tubule after stimulation by the antidiuretic hormone (ADH). The failure to perform this function causes nephrogenic diabetes insipidus (NDI); a disease characterized by the inability of the kidney to concentrate urine and induces the production of high urinary volumes. While recessive mutations generate poorly structured proteins unable to form tetramers, dominant mutations are capable of associating with their wild counterparts, thus generating a NDI even in heterozygous patients. This paper presents the biochemical and functional analysis of T179N, a new NDI-causing mutation of the human AQP2. The mutant is particularly interesting because of its dominant genotype, despite its extracellular position usually restricted to recessive mutations. Here, we compare T179N against archetypal recessive and dominant mutations using both Xenopus laevis oocytes and in mpkCCDc14 cell model, and show the recessive nature of the mutation. The immunoblot tests on oocytes lysates in purified total and plasma membranes revealed that only the wild type protein reaches the plasma membrane while the T179N mutant is sequestered within cellular stores. Accordingly, functional analyzes indicate that T179N is inactive. In mpkCCDc14 cells, T179N expressed alone does not reach the plasma membrane in response to forskolin stimulation, unlike the wild-type. However, T179N does show the capacity to associate with its wild-type counterpart in both oocytes and in mpkCCDc14 cells, although without displaying the typical dominant negative effect. In fact, when coexpressed along wild-type, T179N gains back the functionality, with a Pf increase of 83±7 % and adequate plasma membrane targeting in cells (immunofluorescence). In conclusion, the mutant T179N is a mild recessive mutation that is susceptible to functional recovery when in presence of wild type AQP2.

Keyphrases: Aquaporine 2, Mutation, Aquaporin 2, Nephrogenic diabetes insipidus, Heterologous expression
Adaptations de la méthode de purification d’ARN par affinité avec l’étiquette ARiBo

In recent years, the field of RNA research has exploded due to several discoveries demonstrating the importance of RNA in many biological processes. Along with the increased interest in this field, large amounts of RNA have become essential to the success of several studies, in particular for structural biology and functional characterization. However, there are still very few native purification methods that are simple, efficient and reliable. In the past few years, the Legault laboratory has established an affinity purification method using an ARiBo tag to purify RNAs produced by in vitro transcription with the T7 RNA polymerase. This RNA purification method was specifically developed to maximise purity and yield. In addition, this method is fast and works with several types of RNAs. However, like several other purification methods, this method produces RNAs with 5' heterogeneity. This Master’s thesis propose solutions to overcome the problem of 5' heterogeneity for RNAs transcribed with the T7 RNA polymerase and purified with the ARiBo method. The first solution proposed is to choose a 5' sequence among those of the 32 sequences tested that do not present 5'- heterogeneity. The other possibility is the use of a cleavable tag at the 5'-end of the RNA of interest, such as the hammerhead ribozyme, already used for this purpose or the CRISPR/Cse3 system, which is presented here. Furthermore, we have adapted the ARiBo method to purify an RNA of 614 nt, the miRNAs cluster miR- 106b-25. We also demonstrate the possibility to use the ARiBo method to isolate proteins that bind a given RNA, the miRNA precursor pre-miR-153-2. In conclusion, this Master’s thesis demonstrates the possibility of adapting the ARiBo method for several applications.

Keyphrases: CRISPR/Cse3, RNA affinity purification, ARiBo tag, T7 RNA polymerase, 5' heterogeneity, CRISPR/Cse3, Hammerhead ribozyme, Ribonucleoprotein complex
Étude de l’interaction Ikaros/voie de signalisation Notch au cours de l'érythropoïèse

Throughout the life of an individual, there is an optimal count of cells to produce and progenitors to conserve in stock. This is the tissue homeostasis maintenance. In a general fashion the organism has five means to regulate the homeostasis. Self-renewal and quiescence, often used in order to maintain a functional progenitors pool. Differentiation enhances effector cells production. Apoptosis and senescence can limit cell production and reduce cell number in case of excess. These regulation mechanisms can be performed in an extrinsic fashion using different signaling pathways combined with the action of transcription factors like Ikaros and GATA1. The transcription factor Ikaros is critical for progenitor cells fate and hematopoietic lineages differentiation. However, Ikaros is mostly known for its influence on Notch signaling in lymphoid cells, notably T lymphocytes. Erythroid cells are highly sensitive to the environment thus, particularly adapted to study homeostasis maintenance regulation. Results obtained in different studies showed Ikaros and Notch signaling influencing erythropoiesis. However, the detail of their effect remains mainly unknown to day. Our aim was to determine Ikaros effect on erythroid cells homeostasis maintenance and if its role involved a cross-talk with Notch signaling. We will decipher transcription regulation mechanisms used by Ikaros and Notch during erythropoiesis and their effects. We show Ikaros uses GATA1 to repress Hes1, a major Notch target by recruiting a Polycomb family complex, the PRC2 (Polycomb Repressive Complex 2). This repression promotes erythroid cells differentiation. At the apoptosis mediated control of homeostasis level, Ikaros is known to target Bcl2l1 in lymphocytes. As GATA1, Ikaros preferential partner, targets Bcl2l1 in erythroid cells, we assessed their effect on Bcl2l1 expression. We discovered Ikaros directly activates Bcl2l1 iv and recruits two elongation associated complexes: one from SET1/MLL complex family, and the P-TEFb-NuRD complex. In the absence of Ikaros, the intracellular fragment of Notch (NICD) and its cofactor RBP-J replace Ikaros and favors Bcl2l1 overactivation. This is associated with a switch of recruited elongation associated complex and the establishment of distinct epigenetic modifications from those observed with Ikaros, which modifies the gene transcriptional elongation. Ikaros and Notch are frequently mutated or present altered functions in leukemia. Our works present an Ikaros/Notch cross-talk influencing as well differentiation as apoptosis and reveal the existence of a genetic circuit for which a malfunction could favor hematologic disorders. Keywords : transcription, homeostasis, erythropoiesis

Keyphrases: transcription, Ikaros, Notch, homeostasis, erythropoiesis, epigenetics