Stéphane Chabaud
Laval University
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Featured researches published by Stéphane Chabaud.
Apoptosis | 2011
Florent Dufour; A. Marie-Josée Sasseville; Stéphane Chabaud; Bernard Massie; Richard M. Siegel; Yves Langelier
We previously reported that HSV-2 R1, the R1 subunit (ICP10; UL39) of herpes simplex virus type-2 ribonucleotide reductase, protects cells against apoptosis induced by the death receptor (DR) ligands tumor necrosis factor-alpha- (TNFα) and Fas ligand (FasL) by interrupting DR-mediated signaling at, or upstream of, caspase-8 activation. Further investigation of the molecular mechanism underlying HSV-2 R1 protection showed that extracellular-regulated kinase 1/2 (ERK1/2), phosphatidylinositol 3-kinase (PI3-K)/Akt, NF-κB and JNK survival pathways do not play a major role in this antiapoptotic function. Interaction studies revealed that HSV-2 R1 interacted constitutively with caspase-8. The HSV-2 R1 deletion mutant R1(1-834)-GFP and Epstein–Barr virus (EBV) R1, which did not protect against apoptosis induced by DR ligands, did not interact with caspase-8, indicating that interaction is required for protection. HSV-2 R1 impaired caspase-8 activation induced by caspase-8 over-expression, suggesting that interaction between the two proteins prevents caspase-8 dimerization/activation. HSV-2 R1 bound to caspase-8 directly through its prodomain but did not interact with either its caspase domain or Fas-associated death domain protein (FADD). Interaction between HSV-2 R1 and caspase-8 disrupted FADD-caspase-8 binding. We further demonstrated that individually expressed HSV-1 R1 (ICP6) shares, with HSV-2 R1, the ability to bind caspase-8 and to protect cells against DR-induced apoptosis. Finally, as the long-lived Fas protein remained stable during the early period of infection, experiments with the HSV-1 UL39 deletion mutant ICP6∆ showed that HSV-1 R1 could be essential for the protection of HSV-1-infected cells against FasL.
International Journal of Biological Macromolecules | 2015
Laure Gibot; Stéphane Chabaud; Sara Bouhout; Stéphane Bolduc; François A. Auger; Véronique Moulin
PURPOSE Chitosan, a natural macromolecule, is widely used in medical and pharmaceutical fields because of its distinctive properties such as bactericide, fungicide and above all its antitumor effects. Although its antitumor activity against different types of cancer had been previously described, its mechanism of action was not fully understood. MATERIALS AND METHODS Coating of chitosan has been used in cell cultures with A375, SKMEL28, and RPMI7951 cell lines. Adherence, proliferation and apoptosis were investigated. RESULTS Our results revealed that whereas chitosan decreased adhesion of primary melanoma A375 cell line and decreased proliferation of primary melanoma SKMEL28 cell line, it had potent pro-apoptotic effects against RPMI7951, a metastatic melanoma cell line. In these latter cells, inhibition of specific caspases confirmed that apoptosis was effected through the mitochondrial pathway and Western blot analyses showed that chitosan induced an up regulation of pro-apoptotic molecules such as Bax and a down regulation of anti-apoptotic proteins like Bcl-2 and Bcl-XL. More interestingly, chitosan exposure induced an exposition of a greater number of CD95 receptor at RPMI7951 surface, making them more susceptible to FasL-induced apoptosis. CONCLUSION Our results indicate that chitosan could be a promising agent for further evaluations in antitumor treatments targeting melanoma.
The Scientific World Journal | 2013
Hazem Orabi; Sara Bouhout; Amélie Morissette; Alexandre Rousseau; Stéphane Chabaud; Stéphane Bolduc
Urinary tract is subjected to many varieties of pathologies since birth including congenital anomalies, trauma, inflammatory lesions, and malignancy. These diseases necessitate the replacement of involved organs and tissues. Shortage of organ donation, problems of immunosuppression, and complications associated with the use of nonnative tissues have urged clinicians and scientists to investigate new therapies, namely, tissue engineering. Tissue engineering follows principles of cell transplantation, materials science, and engineering. Epithelial and muscle cells can be harvested and used for reconstruction of the engineered grafts. These cells must be delivered in a well-organized and differentiated condition because water-seal epithelium and well-oriented muscle layer are needed for proper function of the substitute tissues. Synthetic or natural scaffolds have been used for engineering lower urinary tract. Harnessing autologous cells to produce their own matrix and form scaffolds is a new strategy for engineering bladder and urethra. This self-assembly technique avoids the biosafety and immunological reactions related to the use of biodegradable scaffolds. Autologous equivalents have already been produced for pigs (bladder) and human (urethra and bladder). The purpose of this paper is to present a review for the existing methods of engineering bladder and urethra and to point toward perspectives for their replacement.
The Journal of Pathology | 2009
Marie-Pier Corriveau; Ines Boufaied; Julie Lessard; Stéphane Chabaud; Jean-Luc Senécal; Tamara Grodzicky; Suzanne Chartier; Yves Raymond; Véronique Moulin
We set out to examine the pathophysiological mechanisms of fibrosis in diffuse systemic sclerosis (SSc) using a tissue engineering approach. Skin fibroblasts were isolated from lesional skin of SSc patients with a disease duration of less than 1 year (early‐stage SSc) or more than 10 years (late‐stage SSc). Fibroblasts were also isolated from non‐lesional skin and compared with normal fibroblasts isolated from healthy adults. Cells were cultured using a tissue engineering method to reconstruct a human dermis, and histologically observed. Dermal thickness was measured, as it reflects the global and intrinsic capacity of cells to reconstitute matrix. Collagen I, MMP‐1, and MMP activity were evaluated. Cells were treated with TGFβ1 or CTGF during dermis formation to study their fibrogenic role. Clinical severity of skin involvement was measured by a modified Rodnan score. Thickness of the dermis generated with non‐lesional early‐stage SSc fibroblasts was similar to normal cells. In contrast, reconstructed dermis from lesional early‐stage SSc fibroblasts and non‐lesional late‐stage SSc cells was thinner, while lesional late‐stage SSc fibroblasts made a thicker dermis. Dermis was always thicker when produced with TGFβ1‐treated cells, except when lesional late‐stage SSc fibroblasts from patients with high Rodnan skin scores were used. CTGF did not affect dermal thickness. Measurements of collagen I and collagenases in the culture medium of the various reconstructed dermis could explain some of the changes observed. We conclude that the fibrotic phenotype of SSc fibroblasts varies with disease duration and with severity of skin involvement, and this is clearly visualized during in vitro dermis reconstruction. Copyright
European Urology | 2011
Valérie Cattan; Geneviève Bernard; Alexandre Rousseau; Sara Bouhout; Stéphane Chabaud; François A. Auger; Stéphane Bolduc
BACKGROUND A challenge in urologic tissue engineering is to obtain well-differentiated urothelium to overcome the complications related to other sources of tissues used in ureteral and urethral substitution. OBJECTIVE We investigated the effects of in vitro mechanical stimuli on functional and morphologic properties of a human tissue-engineered tubular genitourinary graft (TTGG). DESIGN, SETTING, AND PARTICIPANTS Using the self-assembly technique, we developed a TTGG composed of human dermal fibroblasts and human urothelial cells without exogenous scaffolding. Eight substitutes were subjected to dynamic flow and hydrostatic pressure for up to 2 wk compared to static conditions (n=8). MEASUREMENTS Stratification and cell differentiation were assessed by histology, electron microscopy, immunostaining, and uroplakin gene expression. Barrier function was determined by permeation studies with carbon 14-urea. RESULTS AND LIMITATIONS Dynamic conditions showed well-established stratified urothelium and basement membrane formation, whereas no stratification was observed in static culture. The first signs of cell differentiation were perceived after 7 d of perfusion and were fully expressed at day 14. Superficial cells under perfusion displayed discoidal and fusiform vesicles and positive staining for uroplakin 2, cytokeratine 20, and tight junction protein ZO-1, similar to native urothelium. Mechanical stimuli induced expression of the major uroplakin transcripts, whereas expression was low or undetectable in static culture. Permeation studies showed that mechanical constraints significantly improved the barrier function compared to static conditions (p<0.01 at 14 d, p<0.05 at 7 d) and were comparable to native urothelium. CONCLUSIONS Mechanical stimuli induced in vitro terminal urothelium differentiation in a human genitourinary substitute displaying morphologic and functional properties equivalent to a native urologic conduit.
Journal of Cellular Physiology | 2011
Stéphane Chabaud; Marie-Pier Corriveau; Tamara Grodzicky; Jean-Luc Senécal; Suzanne Chartier; Yves Raymond; Véronique Moulin
Our hypothesis is that the development of lesional areas of skin in patients with systemic sclerosis (SSc) originates from the selection of profibrotic cell subpopulations within their non‐lesional skin areas, due to their greater resistance to apoptosis. Sensitivity to apoptosis of early‐stage or late‐stage SSc fibroblasts as well as of healthy cells was compared using extrinsic or intrinsic apoptotic pathway‐inducers. Subpopulations of non‐lesional SSc cells and healthy cells obtained after repeated Fas‐induced apoptosis were compared with respect to their fibrotic parameters such as collagen and MMP secretion. Only late‐stage lesional SSc cells were more resistant to Fas‐induced apoptosis than their non‐lesional counterparts isolated from the same patient. This result correlated with an increase in the levels of the anti‐apoptotic proteins cFLIPs and cIAP in lesional cells compared to non‐lesional cells. Healthy and non‐lesional cell populations could be selected to generate a subpopulation that was more resistant to apoptosis. However, only the late‐stage non‐lesional SSc fibroblast populations showed a significant decrease in MMP secretion, one of parameters of the fibrosis. Our results show that resistance to apoptosis is an important characteristic of the late‐stage lesional SSc fibroblast phenotype. We thus hypothesized that a selection of specific fibroblast subpopulations from late‐stage non‐lesional SSc skin areas could be at the origin of lesional populations. These cells should become independent of any exogenous stimuli and can induce or maintain SSc skin lesions. J. Cell. Physiol. 226: 1907–1914, 2011.
Journal of Tissue Engineering and Regenerative Medicine | 2017
Stéphane Chabaud; Alexandre Rousseau; Thomas‐Louis Marcoux; Stéphane Bolduc
Although the self‐assembly approach is an efficient method for the production of engineered physiological and pathological tissues, avoiding the use of exogenous materials, it nevertheless remains expensive and requires dexterity, which are features incompatible with large‐scale production. We propose a modification to this technique to make easier the production of mesenchymal compartment, to reduce the cost and to improve the histological quality of the self‐assembled tissues. The stroma produced by this novel approach allowed epithelial cell differentiation, resulting in a pseudostratified epithelium that shared several features with native tissues. The incorporation of endothelial cells in the reconstructed mesenchyme formed a three‐dimensional capillary‐like network, positive for CD31 and von Willebrand factor and surrounded by NG2 positive cells. It could limit self‐contraction of the resulting tissue by recruiting α‐Smooth Muscle Actin positive cells. With this new technique, which is relatively inexpensive and easy to use in a research laboratory set‐up, near‐native stromas can now be produced with minimal handling time. Copyright
Journal of Tissue Engineering and Regenerative Medicine | 2015
Stéphane Chabaud; Thomas‐Louis Marcoux; Marie‐Pier Deschênes‐Rompré; Alexandre Rousseau; Amélie Morissette; Sara Bouhout; Geneviève Bernard; Stéphane Bolduc
The time needed to produce engineered tissue is critical. A self‐assembly approach provided excellent results regarding biological functions and cell differentiation because it closely respected the microenvironment of cells. Nevertheless, the technique was time consuming for producing tissue equivalents with enough extracellular matrix to allow manipulations. Unlike L‐arginine supplementation that only increased accumulation of collagen in cell culture supernatant in our model, addition of lysophosphatidic acid, a natural bioactive lipid, did not modify the amount of accumulated collagen in the cell culture supernatant; however, it enhanced the matrix deposition rate without inducing fibroblast hyperproliferation and tissue fibrosis. Copyright
BioMed Research International | 2015
Raif Eren Ayata; Stéphane Chabaud; Michèle Auger; Roxane Pouliot
Angiogenesis is a fundamental process in healing, tumor growth, and a variety of medical conditions. For this reason, in vitro angiogenesis is an area of interest for researchers. Additionally, in vitro angiogenesis is important for the survival of prevascularized tissue-engineering models. The aim of this study was to observe the self-tubular organization behaviour of endothelial cells in the self-assembly method. In this study, bilayered and dermal substitutes were prepared using the self-assembly method. Histological, immunostaining, and biochemical tests were performed. The behavioural dynamics of endothelial cells in this biological environment of supportive cells were observed, as were the steps of the in vitro angiogenic cascade with self-organizing capillary-like structures formation. The epidermal component of the substitutes was seen to promote network expansion and density. It also increased the quantity of angiogenic factors (VEGF and Ang-1) without increasing the proinflammatory factor (IL-8). In addition, the increased MMP activity contributed to matrix degradation, which facilitated capillary formation.
Archive | 2013
Sara Bouhout; Alexandre Rousseau; Stéphane Chabaud; AmélieMorissette; Stéphane Bolduc
Organism‘s functions are provided by different biological apparatus and one of them is essential for maintaining the integrity of this system. Indeed activities of each organs lead to the cellular production of metabolites. These metabolic products are discharged into the blood system to be supported by the urinary apparatus. The purification of the blood is essential to preserve the homeostasis of the organism and the blood pressure. The upper urinary tract is composed of kidneys which filter the blood to evacuate the excessive water, ions and toxic metabolic products. Then, this mixture called terminal urine is transported in the lower urinary tract by the ureters. The lower urinary tract consists of the bladder which stocks the urine until its evacuation by the urethra. The terminal urine is cytotoxic because of its composition of nitrogenous and potential carcinogenic elements, also its pH which varies between 4.5 and 8.3 [1, 2]. Therefore, the storage of urine need to be safe, this is why the bladder possesses two specific characteristics.