Personne :
Laroche, Gaétan

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Structures organisationnelles
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Université Laval. Département de génie des mines, de la métallurgie et des matériaux
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Voici les éléments 1 - 8 sur 8
  • Publication
    Accès libre
    Interplay of geometric cues and RGD/BMP-2 crosstalk in directing stem cell fate
    (American Chemical Society, 2017-08-21) Bilem, Ibrahim; Laroche, Gaétan; Plawinski, Laurent; Chevallier, Pascale; Sone, E. (Eli); Durrieu, Marie-Christine
    Within the native microenvironment, extracellular matrix (ECM) components are thought to display a complex and heterogeneous distribution, spanning several length scales. Herein, the objective is to mimic, in vitro, the hierarchical organization of proteins and growth factors as well as their crosstalk. Photolithography technique was used to adjacently pattern geometrically defined regions of RGD and BMP-2 mimetic peptides onto glass substrates. These ECM-derived ligands are known to jointly regulate mesenchymal stem cells (MSCs) osteogenic differentiation. By manipulating the spatial distribution of dually grafted peptides, the extent of human MSCs osteogenic differentiation was significantly affected, depending on the shape of peptide micropatterns. Our data highlight the existence of a strong interplay between geometric cues and biochemical signals. Such in vitro systems provide a valuable tool to investigate mechanisms by which multiple ECM cues overlap to regulate stem cell fate, thereby contributing to the design of bioinspired biomaterials for bone tissue engineering applications.
  • Publication
    Accès libre
    Dynamics of endothelial cell responses to laminar shear stress on surfaces functionalized with fibronectin-derived peptides
    (American Chemical Society, 2018-10-11) Duchesne, Carl; Ruel, Jean; Tremblay, Catherine; Juneau, Pierre-Marc; Beland, Ariane V.; Garnier, Alain; Ling, Si Da; Boulanger, Mariève D.; Laroche, Gaétan; Hoesli, Corinne A.; Gaillet, Bruno
    Surface endothelialization could improve the long-term performance of vascular grafts and stents. We previously demonstrated that aerosol-generated fibronectin-derived peptide micropatterns consisting of GRGDS spots over a WQPPRARI background increase endothelial cell yields in static cultures. We developed a novel fluorophore-tagged RGD peptide (RGD-TAMRA) to visualize cell–surface interactions in real-time. Here, we studied the dynamics of endothelial cell response to laminar flow on these peptide-functionalized surfaces. Endothelial cells were exposed to 22 dyn/cm² wall shear stress while acquiring time-lapse images. Cell surface coverage and cell alignment were quantified by undecimated wavelet transform multivariate image analysis. Similar to gelatin-coated surfaces, surfaces with uniform RGD-TAMRA distribution led to cell retention and rapid cell alignment (∼63% of the final cell alignment was reached within 1.5 h), contrary to the micropatterned surfaces. The RGD-TAMRA peptide is a promising candidate for endothelial cell retention under flow, and the spray-based micropatterned surfaces are more promising for static cultures.
  • Publication
    Accès libre
    Directing hMSCs fate through geometrical cues and mimetics peptides
    (John Wiley & Sons, 2019-10-08) Padiolleau, Laurence; Laroche, Gaétan
    The native microenvironment of mesenchymal stem cells (hMSCs)—the extracellular matrix (ECM), is a complex and heterogenous environment structured at different scales. The present study aims at mimicking the hierarchical microorganization of proteins or growth factors within the ECM using the photolithography technique. Polyethylene terephthalate substrates were used as a model material to geometrically defined regions of RGD + BMP‐2 or RDG + OGP mimetic peptides. These ECM‐derived ligands are under research for regulation of mesenchymal stem cells osteogenic differentiation in a synergic manner. The hMSCs osteogenic differentiation was significantly affected by the spatial distribution of dually grafted peptides on surfaces, and hMSCs cells reacted differently according to the shape and size of peptide micropatterns. Our study demonstrates the presence of a strong interplay between peptide geometric cues and stem cell differentiation toward the osteoblastic lineage. These tethered surfaces provide valuable tools to investigate stem cell fate mechanisms regulated by multiple ECM cues, thereby contributing to the design of new biomaterials and improving hMSCs differentiation cues.
  • Publication
    Accès libre
    Human saphenous vein endothelial cell adhesion and expansion on micropatterned polytetrafluoroethylene
    (Wiley, 2012-08-31) Boivin, Marie-Claude; Laroche, Gaétan; Hoesli, Corinne A.; Lagueux, Jean; Bareille, Reine; Rémy-Zolghadri, Murielle; Chevallier, Pascale; Bordenave, Laurence; Durrieu, Marie-Christine
    Intimal hyperplasia and thrombosis are responsible for the poor patency rates of small-diameter vascular grafts. These complications could be avoided by a rapid and strong adhesion of endothelial cells to the prosthetic surfaces, which typically consist of expanded polytetrafluoroethylene (PTFE) for small-diameter vessels. We have previously described two peptide micropatterning strategies that increase the endothelialization rates of PTFE. The micropatterns were generated either by inkjet printing 300 μm squares or by spraying 10.1 ± 0.1 μm diameter droplets of the CGRGDS cell adhesion peptide, while the remaining surface was functionalized using the CWQPPRARI cell migration peptide. We now directly compare these two micropatterning strategies and examine the effect of hydrodynamic stress on human saphenous vein endothelial cells grown on the patterned surfaces. No significant differences in cell adhesion were observed between the two micropatterning methods. When compared to unpatterned surfaces treated with a uniform mixture of the two peptides, the cell expansion was significantly higher on sprayed or printed surfaces after 9 days of static cell culture. In addition, after 6 h of exposure to hydrodynamic stress, the cell retention and cell cytoskeleton reorganization on the patterned surfaces was improved when compared to untreated or random treated surfaces. These results indicate that micropatterned surfaces lead to improved rates of PTFE endothelialization with higher resistance to hydrodynamic stress.
  • Publication
    Accès libre
    A fluorophore-tagged RGD peptide to control endothelial cell adhesion to micropatterned surfaces
    (ScienceDirect, 2013-10-31) Hoesli, Corinne A.; Duchesne, Carl; Juneau, Pierre-Marc; Laroche, Gaétan; Chevallier, Pascale
    The long-term patency rates of vascular grafts and stents are limited by the lack of surface endothelialisation of the implanted materials. We have previously reported that GRGDS and WQPPRARI peptide micropatterns increase the endothelialisation of prosthetic materials in vitro. To investigate the mechanisms by which the peptide micropatterns affect endothelial cell adhesion and proliferation, a TAMRA fluorophore-tagged RGD peptide was designed. Live cell imaging revealed that the micropatterned surfaces led to directional cell spreading dependent on the location of the RGD-TAMRA spots. Focal adhesions formed within 3 h on the micropatterned surfaces near RGD-TAMRA spot edges, as expected for cell regions experiencing high tension. Similar levels of focal adhesion kinase phosphorylation were observed after 3 h on the micropatterned surfaces and on surfaces treated with RGD-TAMRA alone, suggesting that partial RGD surface coverage is sufficient to elicit integrin signaling. Lastly, endothelial cell expansion was achieved in serum-free conditions on gelatin-coated, RGD-TAMRA treated or micropatterned surfaces. These results show that these peptide micropatterns mainly impacted cell adhesion kinetics rather than cell proliferation. This insight will be useful for the optimization of micropatterning strategies to improve vascular biomaterials.
  • Publication
    Accès libre
    RGD and BMP-2 mimetic peptides crosstalk enhances osteogenic commitment of human bone marrow stem cells
    (Elsevier, 2016-03-18) Bilem, Ibrahim; Laroche, Gaétan; Plawinski, Laurent; Chevallier, Pascale; Stone, E.; Durrieu, Marie-Christine
    Human bone marrow mesenchymal stem cells (hBMSCs) commitment and differentiation are dictated by bioactive molecules sequestered within their Extra Cellular Matrix (ECM). One common approach to mimic the physiological environment is to functionalize biomaterial surfaces with ECM-derived peptides able to recruit stem cells and trigger their linage-specific differentiation. The objective of this work was to investigate combinatorial effects of RGD and BMP-2 mimetic peptides on the osteogenic commitment of hBMSCs, without supplementing the media with pro-osteogenic factors. The RGD peptide promotes cell adhesion via cell transmembrane integrin receptors, while the BMP-2 peptide, corresponding to residues 73-92 of Bone Morphogenetic Protein-2, was shown to induce hBMSCs osteoblast differentiation. The immobilization of peptides on aminated glass was ascertained by X-ray Photoelectron Spectroscopy (XPS), the density of grafted peptides was quantified by fluorescence microscopy and the surface roughness was evaluated using Atomic Force Microscopy (AFM). The osteogenic commitment of hBMSCs cultured on RGD and/or BMP-2 surfaces was characterized by immunohistochemistry using STRO-1 as specific stem cells marker and Runx-2 as an earlier osteogenic marker. Biological results showed that the osteogenic commitment of hBMSCs was enhanced on bifunctionalized surfaces as compared to surfaces containing BMP-2, while on RGD surfaces cells mainly preserved their stemness character. These results demonstrated that RGD and BMP-2 mimetic peptides act synergistically to enhance hBMSCs osteogenesis without supplementing the media with osteogenic factors. These findings contribute to the development of biomimetic materials, allowing a deeper understanding of signaling pathways that govern the transition of stem cells towards the osteoblastic lineage.
  • Publication
    Accès libre
    Single or mixed tethered peptides to promote hMSC differentiation toward osteoblastic lineage
    (American Chemical Society, 2018-11-27) Padiolleau, Laurence; Chanseau, Christel; Laroche, Gaétan; Durrieu, Stephanie; Chevallier, Pascale; Durrieu, Marie-Christine
    The commitment and differentiation of human mesenchymal stem cells (hMSCs) are guided by bioactive molecules within the extracellular matrix. Among the various approaches to design biomaterials, the functionalization of biomaterial surfaces with peptides from the sequence of proteins from the extracellular matrix is quite common. The purpose of this functionalization is to recruit hMSCs and promote their differentiation into the appropriate lineage. The aim of this work was to investigate the influence of RGD and FHRRIKA peptides and peptide sequences taken from bone morphogenic protein (BMP-2) and histone H4 (osteogenic growth peptide; OGP) either tethered alone or as a mixture on the surface of a model material and to also examine the level of hMSC osteogenic commitment without using a differentiation medium. Grafting of the different peptides was assessed by X-ray photoelectron spectroscopy (XPS), while their surface density was quantified by fluorescence microscopy, and their surface properties were assessed by atomic force microscopy (AFM) and contact angle (CA). The osteogenic commitment of hMSCs cultured on the different surfaces was characterized by immunohistochemistry using Runx-2 as an earlier osteogenic marker and OPN, a late osteogenic marker, and by RT-qPCR through the expression of ColI-a1, Runx-2, and ALP. Biological results show that the osteogenic commitment of the hMSCs was increased on surfaces tethered with a mixture of peptides. Results indicate that tethered peptides in the range of pmol mm–2 were indeed effective in inducing a cellular response after 2 weeks of cell culture without using an osteogenic media. These findings contribute to the research efforts to design biomimetic materials able to induce a response in human stem cells through tethered bioactive molecules for bone tissue engineering.
  • Publication
    Accès libre
    The spatial distribution of RGD and BMP-2 mimetic peptides at the subcellular scale modulates human mesenchymal stem cells osteogenesis
    (Society for Biomaterials, 2017-11-16) Bilem, Ibrahim; Plawinski, Laurent; Laroche, Gaétan; Chevallier, Pascale; Ayela, Cédric; Sone, E.; Durrieu, Marie-Christine
    Engineering artificial extracellular matrices, based on the biomimicry of the spatial distribution of proteins and growth factors within their native microenvironment, is of great importance for understanding mechanisms of bone tissue regeneration. Herein, photolithography is used to decorate glass surfaces with subcellular patterns of RGD and BMP‐2 ligands; two mimetic peptides recognized to be involved in stem cells osteogenesis. The biological relevance of well‐defined RGD and BMP‐2 patterned surfaces is evaluated by investigating the differentiation of human mesenchymal stem cells (hMSCs) into osteoblasts, in the absence of induction media. The extent of hMSCs differentiation is revealed to be dependent on both the pattern shape and the ligand type. Indeed, the spatial patterning of BMP‐2, but not RGD peptide, significantly enhances the extent of hMSCs differentiation, suggesting that geometric cues guide stem cells specification into specialized cells in a ligand type dependent manner. Such cell culture models provide an interesting tool to investigate how stem cells perceive and respond to their microenvironment and may contribute to the development of next‐generation biomaterials capable of producing clinically relevant volume of bone tissue.