scholarly journals Behaviour of Endothelial Cells in a TridimensionalIn VitroEnvironment

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Raif Eren Ayata ◽  
Stéphane Chabaud ◽  
Michèle Auger ◽  
Roxane Pouliot
Keyword(s):  
Endothelial Cells ◽  
Self Assembly ◽  
The Self ◽  
Biochemical Tests ◽  
Area Of Interest ◽  
Assembly Method ◽  
Engineering Models ◽  
Prevascularized Tissue ◽  
Biological Environment

Angiogenesis is a fundamental process in healing, tumor growth, and a variety of medical conditions. For this reason,in vitroangiogenesis is an area of interest for researchers. Additionally,in vitroangiogenesis 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 thein vitroangiogenic 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.

scholarly journals Human Organ-Specific 3D Cancer Models Produced by the Stromal Self-Assembly Method of Tissue Engineering for the Study of Solid Tumors

2020 ◽  
Vol 2020 ◽  
pp. 1-23 ◽  
Author(s):  
Vincent Roy ◽  
Brice Magne ◽  
Maude Vaillancourt-Audet ◽  
Mathieu Blais ◽  
Stéphane Chabaud ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Tumor Microenvironment ◽  
Self Assembly ◽  
The Self ◽  
Human Organ ◽  
Assembly Method ◽  
Cancer Models ◽  
Organ Specific

Cancer research has considerably progressed with the improvement of in vitro study models, helping to understand the key role of the tumor microenvironment in cancer development and progression. Over the last few years, complex 3D human cell culture systems have gained much popularity over in vivo models, as they accurately mimic the tumor microenvironment and allow high-throughput drug screening. Of particular interest, in vitrohuman 3D tissue constructs, produced by the self-assembly method of tissue engineering, have been successfully used to model the tumor microenvironment and now represent a very promising approach to further develop diverse cancer models. In this review, we describe the importance of the tumor microenvironment and present the existing in vitro cancer models generated through the self-assembly method of tissue engineering. Lastly, we highlight the relevance of this approach to mimic various and complex tumors, including basal cell carcinoma, cutaneous neurofibroma, skin melanoma, bladder cancer, and uveal melanoma.

scholarly journals Engineering Tissues without the Use of a Synthetic Scaffold: A Twenty-Year History of the Self-Assembly Method

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Ingrid Saba ◽  
Weronika Jakubowska ◽  
Stéphane Bolduc ◽  
Stéphane Chabaud
Keyword(s):  
Extracellular Matrix ◽  
Self Assembly ◽  
Large Scale ◽  
Dermal Fibroblasts ◽  
The Self ◽  
Production Costs ◽  
Scale Production ◽  
Assembly Method ◽  
Assembly Technique

Twenty years ago, Dr. François A. Auger, the founder of the Laboratory of Experimental Organogenesis (LOEX), introduced the self-assembly technique. This innovative technique relies on the ability of dermal fibroblasts to produce and assemble their own extracellular matrix, differing from all other tissue-engineering techniques that use preformed synthetic scaffolds. Nevertheless, the use of the self-assembly technique was limited for a long time due to its main drawbacks: time and cost. Recent scientific breakthroughs have addressed these limitations. New protocol modifications that aim at increasing the rate of extracellular matrix formation have been proposed to reduce the production costs and laboratory handling time of engineered tissues. Moreover, the introduction of vascularization strategies in vitro permits the formation of capillary-like networks within reconstructed tissues. These optimization strategies enable the large-scale production of inexpensive native-like substitutes using the self-assembly technique. These substitutes can be used to reconstruct three-dimensional models free of exogenous materials for clinical and fundamental applications.

scholarly journals Specialized Living Wound Dressing Based on the Self-Assembly Approach of Tissue Engineering

2018 ◽  
Vol 9 (3) ◽  
pp. 53 ◽  
Author(s):  
Laurence Cantin-Warren ◽  
Rina Guignard ◽  
Sergio Cortez Ghio ◽  
Danielle Larouche ◽  
François Auger ◽  
...  
Keyword(s):  
Self Assembly ◽  
Wound Dressing ◽  
Reference Method ◽  
The Self ◽  
Wound Dressings ◽  
Skin Substitute ◽  
Seeding Density ◽  
Skin Substitutes ◽  
Assembly Method

There is a high incidence of failure and recurrence for chronic skin wounds following conventional therapies. To promote healing, the use of skin substitutes containing living cells as wound dressings has been proposed. The aim of this study was to produce a scaffold-free cell-based bilayered tissue-engineered skin substitute (TES) containing living fibroblasts and keratinocytes suitable for use as wound dressing, while considering production time, handling effort during the manufacturing process, and stability of the final product. The self-assembly method, which relies on the ability of mesenchymal cells to secrete and organize connective tissue sheet sustaining keratinocyte growth, was used to produce TESs. Three fibroblast-seeding densities were tested to produce tissue sheets. At day 17, keratinocytes were added onto 1 or 3 (reference method) stacked tissue sheets. Four days later, TESs were subjected either to 4, 10, or 17 days of culture at the air–liquid interface (A/L). All resulting TESs were comparable in terms of their histological aspect, protein expression profile and contractile behavior in vitro. However, signs of extracellular matrix (ECM) digestion that progressed over culture time were noted in TESs produced with only one fibroblast-derived tissue sheet. With lower fibroblast density, the ECM of TESs was almost completely digested after 10 days A/L and lost histological integrity after grafting in athymic mice. Increasing the fibroblast seeding density 5 to 10 times solved this problem. We conclude that the proposed method allows for a 25-day production of a living TES, which retains its histological characteristics in vitro for at least two weeks.

Enhanced Entrapment and Improved in Vitro Controlled Release of N-Acetyl Cysteine in Hybrid PLGA/Lecithin Nanoparticles Prepared Using a Nanoprecipitation/Self-Assembly Method

2017 ◽  
Vol 118 (12) ◽  
pp. 4203-4209 ◽  
Author(s):  
Parvin Ahmaditabar ◽  
Amir A. Momtazi-Borojeni ◽  
Ali H. Rezayan ◽  
Mahboobeh Mahmoodi ◽  
Amirhossein Sahebkar ◽  
...  
Keyword(s):  
Controlled Release ◽  
Self Assembly ◽  
Assembly Method ◽  
Acetyl Cysteine

scholarly journals Biochemical reconstitutions reveal principles of human γ-TuRC assembly and function

2021 ◽  
Vol 220 (3) ◽  
Author(s):  
Michal Wieczorek ◽  
Shih-Chieh Ti ◽  
Linas Urnavicius ◽  
Kelly R. Molloy ◽  
Amol Aher ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
The Self ◽  
Dependent Manner ◽  
Guanine Nucleotide ◽  
Partial Cone ◽  
Ring Complex ◽  
Microtubule Networks ◽  
And Function

The formation of cellular microtubule networks is regulated by the γ-tubulin ring complex (γ-TuRC). This ∼2.3 MD assembly of >31 proteins includes γ-tubulin and GCP2-6, as well as MZT1 and an actin-like protein in a “lumenal bridge” (LB). The challenge of reconstituting the γ-TuRC has limited dissections of its assembly and function. Here, we report a biochemical reconstitution of the human γ-TuRC (γ-TuRC-GFP) as a ∼35 S complex that nucleates microtubules in vitro. In addition, we generate a subcomplex, γ-TuRCΔLB-GFP, which lacks MZT1 and actin. We show that γ-TuRCΔLB-GFP nucleates microtubules in a guanine nucleotide–dependent manner and with similar efficiency as the holocomplex. Electron microscopy reveals that γ-TuRC-GFP resembles the native γ-TuRC architecture, while γ-TuRCΔLB-GFP adopts a partial cone shape presenting only 8–10 γ-tubulin subunits and lacks a well-ordered lumenal bridge. Our results show that the γ-TuRC can be reconstituted using a limited set of proteins and suggest that the LB facilitates the self-assembly of regulatory interfaces around a microtubule-nucleating “core” in the holocomplex.

scholarly journals Structure of artificial and natural VE-cadherinbased adherens junctions

2008 ◽  
Vol 36 (2) ◽  
pp. 189-193 ◽  
Author(s):  
Jean-Christophe Taveau ◽  
Mathilde Dubois ◽  
Olivier Le Bihan ◽  
Sylvain Trépout ◽  
Sébastien Almagro ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Actin Cytoskeleton ◽  
Self Assembly ◽  
Adherens Junctions ◽  
Actin Binding ◽  
Vascular Endothelial ◽  
Vascular Integrity ◽  
Trans Orientation ◽  
Annexin 2

In vascular endothelium, adherens junctions between endothelial cells are composed of VE-cadherin (vascular endothelial cadherin), an adhesive receptor that is crucial for the proper assembly of vascular structures and the maintenance of vascular integrity. As a classical cadherin, VE-cadherin links endothelial cells together by homophilic interactions mediated by its extracellular part and associates intracellularly with the actin cytoskeleton via catenins. Although, from structural crystallographic data, a dimeric structure arranged in a trans orientation has emerged as a potential mechanism of cell–cell adhesion, the cadherin organization within adherens junctions remains controversial. Concerning VE-cadherin, its extracellular part possesses the capacity to self-associate in solution as hexamers consisting of three antiparallel cadherin dimers. VE-cadherin-based adherens junctions were reconstituted in vitro by assembly of a VE-cadherin EC (extracellular repeat) 1–EC4 hexamer at the surfaces of liposomes. The artificial adherens junctions revealed by cryoelectron microscopy appear as a two-dimensional self-assembly of hexameric structures. This cadherin organization is reminiscent of that found in native desmosomal junctions. Further structural studies performed on native VE-cadherin junctions would provide a better understanding of the cadherin organization within adherens junctions. Homophilic interactions between cadherins are strengthened intracellularly by connection to the actin cytoskeleton. Recently, we have discovered that annexin 2, an actin-binding protein connects the VE-cadherin–catenin complex to the actin cytoskeleton. This novel link is labile and promotes the endothelial cell switch from a quiescent to an angiogenic state.

Electrochemical Behavior of a 4-Nitrothiophenol Modified Electrode Prepared by the Self-Assembly Method

1995 ◽  
Vol 171 (2) ◽  
pp. 505-511 ◽  
Author(s):  
Hiromori Tsutsumi ◽  
Shozo Furumoto ◽  
Masayuki Morita ◽  
Yoshiharu Matsuda
Keyword(s):  
Modified Electrode ◽  
Electrochemical Behavior ◽  
Self Assembly ◽  
The Self ◽  
Assembly Method

Shape-controlled synthesis of cubic-like selenium nanoparticles via the self-assembly method

2016 ◽  
Vol 153 ◽  
pp. 435-444 ◽  
Author(s):  
Urarika Luesakul ◽  
Seamkwan Komenek ◽  
Songchan Puthong ◽  
Nongnuj Muangsin
Keyword(s):  
Self Assembly ◽  
The Self ◽  
Selenium Nanoparticles ◽  
Controlled Synthesis ◽  
Assembly Method ◽  
Shape Controlled

scholarly journals Reconstitution of selective HIV-1 RNA packaging in vitro by membrane-bound Gag assemblies

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Lars-Anders Carlson ◽  
Yun Bai ◽  
Sarah C Keane ◽  
Jennifer A Doudna ◽  
James H Hurley
Keyword(s):  
Self Assembly ◽  
Untranslated Region ◽  
Minimal System ◽  
The Self ◽  
Viral Rna ◽  
Large Excess ◽  
Rna Packaging ◽  
Membrane Bound ◽  
Hiv 1

HIV-1 Gag selects and packages a dimeric, unspliced viral RNA in the context of a large excess of cytosolic human RNAs. As Gag assembles on the plasma membrane, the HIV-1 genome is enriched relative to cellular RNAs by an unknown mechanism. We used a minimal system consisting of purified RNAs, recombinant HIV-1 Gag and giant unilamellar vesicles to recapitulate the selective packaging of the 5’ untranslated region of the HIV-1 genome in the presence of excess competitor RNA. Mutations in the CA-CTD domain of Gag which subtly affect the self-assembly of Gag abrogated RNA selectivity. We further found that tRNA suppresses Gag membrane binding less when Gag has bound viral RNA. The ability of HIV-1 Gag to selectively package its RNA genome and its self-assembly on membranes are thus interdependent on one another.

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