29 results on '"Mirren Charnley"'
Search Results
2. Characterization of Amyloid Fibril Networks by Atomic Force Microscopy
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Mirren Charnley, Jay Gilbert, Owen Jones, and Nicholas Reynolds
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Biology (General) ,QH301-705.5 - Abstract
Dense networks of amyloid nanofibrils fabricated from common globular proteins adsorbed to solid supports can improve cell adhesion, spreading and differentiation compared to traditional flat, stiff 2D cell culture substrates like Tissue Culture Polystyrene (TCPS). This is due to the fibrous, nanotopographic nature of the amyloid fibril networks and the fact that they closely mimic the mechanical properties and architecture of the extracellular matrix (ECM). However, precise cell responses are strongly dependent on the nanostructure of the network at the cell culture interface, thus accurate characterization of the immobilized network is important. Due to its exquisite lateral resolution and simple sample preparation techniques, Atomic Force Microscopy (AFM) is an ideal technique to characterize the fibril network morphology. Thus, here we describe a detailed protocol, for the characterization of amyloid fibril networks by tapping mode AFM.
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- 2018
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3. Preparation of Amyloid Fibril Networks
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Mirren Charnley, Jay Gilbert, Owen Jones, and Nicholas Reynolds
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Biology (General) ,QH301-705.5 - Abstract
Networks of amyloid nanofibrils fabricated from common globular proteins such as lysozyme and β-lactoglobulin have material properties that mimic the extracellular microenvironment of many cell types. Cells cultured on such amyloid fibril networks show improved attachment, spreading and in the case of mesenchymal stem cells improved differentiation. Here we describe a detailed protocol for fabricating amyloid fibril networks suitable for eukaryotic cell culture applications.
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- 2018
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4. Effect of Cell Shape and Dimensionality on Spindle Orientation and Mitotic Timing.
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Mirren Charnley, Fabian Anderegg, René Holtackers, Marcus Textor, and Patrick Meraldi
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Medicine ,Science - Abstract
The formation and orientation of the mitotic spindle is a critical feature of mitosis. The morphology of the cell and the spatial distribution and composition of the cells' adhesive microenvironment all contribute to dictate the position of the spindle. However, the impact of the dimensionality of the cells' microenvironment has rarely been studied. In this study we present the use of a microwell platform, where the internal surfaces of the individual wells are coated with fibronectin, enabling the three-dimensional presentation of adhesive ligands to single cells cultured within the microwells. This platform was used to assess the effect of dimensionality and cell shape in a controlled microenvironment. Single HeLa cells cultured in circular microwells exhibited greater tilting of the mitotic spindle, in comparison to cells cultured in square microwells. This correlated with an increase in the time required to align the chromosomes at the metaphase plate due to prolonged activation of the spindle checkpoint in an actin dependent process. The comparison to 2D square patterns revealed that the dimensionality of cell adhesions alone affected both mitotic timings and spindle orientation; in particular the role of actin varied according to the dimensionality of the cells' microenvironment. Together, our data revealed that cell shape and the dimensionality of the cells' adhesive environment impacted on both the orientation of the mitotic spindle and progression through mitosis.
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- 2013
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5. Controlled breast cancer microarrays for the deconvolution of cellular multilayering and density effects upon drug responses.
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Maria Håkanson, Stefan Kobel, Matthias P Lutolf, Marcus Textor, Edna Cukierman, and Mirren Charnley
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Medicine ,Science - Abstract
Increasing evidence shows that the cancer microenvironment affects both tumorigenesis and the response of cancer to drug treatment. Therefore in vitro models that selectively reflect characteristics of the in vivo environment are greatly needed. Current methods allow us to screen the effect of extrinsic parameters such as matrix composition and to model the complex and three-dimensional (3D) cancer environment. However, 3D models that reflect characteristics of the in vivo environment are typically too complex and do not allow the separation of discrete extrinsic parameters.In this study we used a poly(ethylene glycol) (PEG) hydrogel-based microwell array to model breast cancer cell behavior in multilayer cell clusters that allows a rigorous control of the environment. The innovative array fabrication enables different matrix proteins to be integrated into the bottom surface of microwells. Thereby, extrinsic parameters including dimensionality, type of matrix coating and the extent of cell-cell adhesion could be independently studied. Our results suggest that cell to matrix interactions and increased cell-cell adhesion, at high cell density, induce independent effects on the response to Taxol in multilayer breast cancer cell clusters. In addition, comparing the levels of apoptosis and proliferation revealed that drug resistance mediated by cell-cell adhesion can be related to altered cell cycle regulation. Conversely, the matrix-dependent response to Taxol did not correlate with proliferation changes suggesting that cell death inhibition may be responsible for this effect.The application of the PEG hydrogel platform provided novel insight into the independent role of extrinsic parameters controlling drug response. The presented platform may not only become a useful tool for basic research related to the role of the cancer microenvironment but could also serve as a complementary platform for in vitro drug development.
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- 2012
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6. Substrate adhesion regulates sealing zone architecture and dynamics in cultured osteoclasts.
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Fabian Anderegg, Dafna Geblinger, Peter Horvath, Mirren Charnley, Marcus Textor, Lia Addadi, and Benjamin Geiger
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Medicine ,Science - Abstract
The bone-degrading activity of osteoclasts depends on the formation of a cytoskeletal-adhesive super-structure known as the sealing zone (SZ). The SZ is a dynamic structure, consisting of a condensed array of podosomes, the elementary adhesion-mediating structures of osteoclasts, interconnected by F-actin filaments. The molecular composition and structure of the SZ were extensively investigated, yet despite its major importance for bone formation and remodelling, the mechanisms underlying its assembly and dynamics are still poorly understood. Here we determine the relations between matrix adhesiveness and the formation, stability and expansion of the SZ. By growing differentiated osteoclasts on micro-patterned glass substrates, where adhesive areas are separated by non-adhesive PLL-g-PEG barriers, we show that SZ growth and fusion strictly depend on the continuity of substrate adhesiveness, at the micrometer scale. We present a possible model for the role of mechanical forces in SZ formation and reorganization, inspired by the current data.
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- 2011
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7. E-cadherin in developing murine T cells controls spindle alignment and progression through β-selection
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Mirren Charnley, Amr H. Allam, Lucas M. Newton, Patrick O. Humbert, and Sarah M. Russell
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Multidisciplinary - Abstract
A critical stage of T cell development is β-selection; at this stage, the T cell receptor β (TCRβ) chain is generated, and the developing T cell starts to acquire antigenic specificity. Progression through β-selection is assisted by low-affinity interactions between the nascent TCRβ chain and peptide presented on stromal major histocompatibility complex and cues provided by the niche. In this study, we identify a cue within the developing T cell niche that is critical for T cell development. E-cadherin mediates cell-cell interactions and influences cell fate in many developmental systems. In developing T cells, E-cadherin contributed to the formation of an immunological synapse and the alignment of the mitotic spindle with the polarity axis during division, which facilitated subsequent T cell development. Collectively, these data suggest that E-cadherin facilitates interactions with the thymic niche to coordinate the β-selection stage of T cell development.
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- 2023
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8. Neurotoxic Amyloidogenic Peptides Identified in the Proteome of SARS-COV2: Potential Implications for Neurological Symptoms in COVID-19
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Mark D. Hulett, Jiangtao Zhou, Raffaele Mezzenga, Julian Ratcliffe, Joshua T. Berryman, Guneet K. Bindra, Saba Islam, Mirren Charnley, Kyunghoon Han, and Nicholas P. Reynolds
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Amyloid ,business.industry ,Central nervous system ,Inflammation ,Bioinformatics ,medicine.disease ,Virus ,medicine.anatomical_structure ,Proteome ,medicine ,Etiology ,Headaches ,medicine.symptom ,business ,Stroke - Abstract
COVID-19 is primarily known as a respiratory disease caused by the virus SARS-CoV-2. However, neurological symptoms such as memory loss, sensory confusion, cognitive and psychiatric issues, severe headaches, and even stroke are reported in as many as 30% of cases and can persist even after the infection is over (so-called ‘long COVID’). These neurological symptoms are thought to be caused by brain inflammation, triggered by the virus infecting the central nervous system of COVID-19 patients, however we still don’t fully understand the mechanisms for these symptoms. The neurological effects of COVID-19 share many similarities to neurodegenerative diseases such as Alzheimer’s and Parkinson’s in which the presence of cytotoxic protein-based amyloid aggregates is a common etiological feature. Following the hypothesis that some neurological symptoms of COVID-19 may also follow an amyloid etiology we performed a bioinformatic scan of the SARS-CoV-2 proteome, detecting peptide fragments that were predicted to be highly amyloidogenic. We selected two of these peptides and discovered that they do rapidly self-assemble into amyloid. Furthermore, these amyloid assemblies were shown to be highly toxic to a neuronal cell line. We introduce and support the idea that cytotoxic amyloid aggregates of SARS-CoV-2 proteins are causing some of the neurological symptoms commonly found in COVID-19 and contributing to long COVID, especially those symptoms which are novel to long COVID in contrast to other post-viral syndromes.
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- 2021
9. Stepwise progression of β-selection during T cell development as revealed by histone deacetylation inhibition
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Anchi S Chann, Mirren Charnley, Lucas M. Newton, Andrea Newbold, Florian Wiede, Tony Tiganis, Patrick O Humbert, Ricky W Johnstone, and Sarah M Russell
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biology ,Chemistry ,T cell ,T-cell receptor ,CD28 ,hemic and immune systems ,chemical and pharmacologic phenomena ,HDAC6 ,Cell biology ,medicine.anatomical_structure ,Histone ,Downregulation and upregulation ,Acetylation ,medicine ,biology.protein ,Beta (finance) - Abstract
During T cell development, the first step in creating a unique T Cell Receptor (TCR) is the genetic recombination of the TCRβ chain. The quality of the newly recombined TCRβ is assessed at the β-selection checkpoint. Most cells fail this checkpoint and die, but the coordination of the complex events that control fate at the β-selection checkpoint is not yet understood. We shed new light on fate determination during β-selection using a selective inhibitor of histone deacetylase 6, ACY1215. ACY1215 disrupted the β-selection checkpoint. Characterising the basis for this disruption revealed a new, pivotal stage in β-selection, bookended by upregulation of the TCR co-receptors, CD28 and CD2 respectively. Within this ‘DN3bPre’stage, CD5 and Lef1 are upregulated to reflect pre-TCR signalling and their expression correlates with proliferation. During this phase, ACY1215-mediated disruption of the organisation of the β-selection immunological synapse is associated with a breakdown in connectivity of expression of pre-TCR, CD5 and Lef1. Subsequent deregulation of pre-TCR-induced proliferation leads to bypass of the β-selection checkpoint and subsequent failure to progress. We propose that the progressive expression of CD28, CD5 and Lef1, then CD2 reports and modulates the pre-TCR signal to orchestrate passage through the β-selection checkpoint. These findings suggest a refined model of β-selection in which a coordinated increase in expression of pre-TCR, CD28, CD5 and Lef1 allows for modulating TCR signalling strength, and culminates in the expression of CD2 to enable exit from the β-selection checkpoint.
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- 2021
10. Stepwise progression of β-selection during T cell development involves histone deacetylation
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Anchi S Chann, Mirren Charnley, Lucas M Newton, Andrea Newbold, Florian Wiede, Tony Tiganis, Patrick O Humbert, Ricky W Johnstone, and Sarah M Russell
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Histones ,CD28 Antigens ,Ecology ,Receptors, Antigen, T-Cell, alpha-beta ,T-Lymphocytes ,Health, Toxicology and Mutagenesis ,Receptors, Antigen, T-Cell ,Plant Science ,Histone Deacetylase 6 ,Biochemistry, Genetics and Molecular Biology (miscellaneous) - Abstract
During T cell development, the first step in creating a unique T cell receptor (TCR) is genetic recombination of the TCRβ chain. The quality of the new TCRβ is assessed at the β-selection checkpoint. Most cells fail this checkpoint and die, but the coordination of fate at the β-selection checkpoint is not yet understood. We shed new light on fate determination during β-selection using a selective inhibitor of histone deacetylase 6, ACY1215. ACY1215 disrupted the β-selection checkpoint. Characterising the basis for this disruption revealed a new, pivotal stage in β-selection, bookended by up-regulation of TCR co-receptors, CD28 and CD2, respectively. Within this “DN3bPre” stage, CD5 and Lef1 are up-regulated to reflect pre-TCR signalling, and their expression correlates with proliferation. These findings suggest a refined model of β-selection in which a coordinated increase in expression of pre-TCR, CD28, CD5 and Lef1 allows for modulating TCR signalling strength and culminates in the expression of CD2 to enable exit from the β-selection checkpoint.
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- 2022
11. Photothermal release and recovery of mesenchymal stem cells from substrates functionalized with gold nanorods
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Peter F. M. Choong, Yashaswini Vegi, Carmine Onofrillo, Christopher J. H. Chong, Blanca del Rosal, Nerida Cole, Simon E. Moulton, Nicholas P. Reynolds, Paul R. Stoddart, Mirren Charnley, and Stuart K. Earl
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Nanotubes ,Chemistry ,Infrared Rays ,0206 medical engineering ,Mesenchymal stem cell ,Biomedical Engineering ,Mesenchymal Stem Cells ,02 engineering and technology ,General Medicine ,Photothermal therapy ,Surface Plasmon Resonance ,021001 nanoscience & nanotechnology ,020601 biomedical engineering ,Biochemistry ,Regenerative medicine ,Cell biology ,Biomaterials ,Transplantation ,Tissue engineering ,Cell culture ,Stem cell ,0210 nano-technology ,Molecular Biology ,Immortalised cell line ,Biotechnology - Abstract
Mesenchymal stem cell therapies show great promise in regenerative medicine. However, to generate clinically relevant numbers of these stem cells, significant in vitro expansion of the cells is required before transplantation into the affected wound or defect. The current gold standard protocol for recovering in vitro cultured cells involves treatment with enzymes such as trypsin which can affect the cell phenotype and ability to interact with the environment. Alternative enzyme free methods of adherent cell recovery have been investigated, but none match the convenience and performance of enzymatic detachment. In this work we have developed a synthetically simple, low cost cell culture substrate functionalized with gold nanorods that can support cell proliferation and detachment. When these nanorods are irradiated with biocompatible low intensity near infrared radiation (785 nm, 560 mWcm-2) they generate localized surface plasmon resonance induced nanoscale heating effects which trigger detachment of adherent mesenchymal stem cells. Through simulations and thermometry experiments we show that this localized heating is concentrated at the cell-nanorod interface, and that the stem cells detached using this technique show either similar or improved multipotency, viability and ability to differentiate into clinically desirable osteo and adipocytes, compared to enzymatically harvested cells. This proof-of-principle work shows that photothermally mediated cell detachment is a promising method for recovering mesenchymal stem cells from in vitro culture substrates, and paves the way for further studies to scale up this process and facilitate its clinical translation. STATEMENT OF SIGNIFICANCE: New non-enzymatic methods of harvesting adherent cells without damaging or killing them are highly desirable in fields such as regenerative medicine. Here, we present a synthetically simple, non-toxic, infra-red induced method of harvesting mesenchymal stem cells from gold nanorod functionalized substrates. The detached cells retain their ability to differentiate into therapeutically valuable osteo and adipocytes. This work represents a significant improvement on similar cell harvesting studies due to: its simplicity; the use of clinically valuable stem cells as oppose to immortalized cell lines; and the extensive cellular characterization performed. Understanding, not just if cells live or die but how they proliferate and differentiate after photothermal detachment will be essential for the translation of this and similar techniques into commercial devices.
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- 2021
12. Developing T cells form an immunological synapse for passage through the β-selection checkpoint
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Kim Pham, Sarah M. Russell, Amr H. Allam, and Mirren Charnley
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Receptors, CXCR4 ,Stromal cell ,Cell cycle checkpoint ,Immunological Synapses ,T cell ,Receptors, Antigen, T-Cell, alpha-beta ,T-Lymphocytes ,Cell ,Immunology ,Thymus Gland ,Major histocompatibility complex ,Models, Biological ,Article ,Immunological synapse ,Major Histocompatibility Complex ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Animals ,Humans ,030304 developmental biology ,Adaptor Proteins, Signal Transducing ,Cell Proliferation ,0303 health sciences ,biology ,Polarity ,Receptors, Notch ,T-cell receptor ,Molecular Mimicry ,Cell Polarity ,Membrane Proteins ,Cell Biology ,Actins ,Cell biology ,Mice, Inbred C57BL ,medicine.anatomical_structure ,biology.protein ,Signal transduction ,Stromal Cells ,Microtubule-Organizing Center ,030215 immunology ,Signal Transduction - Abstract
During T cell development, genomic rearrangement must create a T cell receptor capable of transmitting signals. Allam et al. show that passage through the β-selection checkpoint requires the assembly of a platform to support TCR signaling, similar to the mature T cell immunological synapse., The β-selection checkpoint of T cell development tests whether the cell has recombined its genomic DNA to produce a functional T cell receptor β (TCRβ). Passage through the β-selection checkpoint requires the nascent TCRβ protein to mediate signaling through a pre-TCR complex. In this study, we show that developing T cells at the β-selection checkpoint establish an immunological synapse in in vitro and in situ, resembling that of the mature T cell. The immunological synapse is dependent on two key signaling pathways known to be critical for the transition beyond the β-selection checkpoint, Notch and CXCR4 signaling. In vitro and in situ analyses indicate that the immunological synapse promotes passage through the β-selection checkpoint. Collectively, these data indicate that developing T cells regulate pre-TCR signaling through the formation of an immunological synapse. This signaling platform integrates cues from Notch, CXCR4, and MHC on the thymic stromal cell to allow transition beyond the β-selection checkpoint.
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- 2021
13. Developing T cells form an immunological synapse for passage through the β−selection checkpoint
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Sarah M. Russell, Amr H. Allam, Mirren Charnley, and Kim Pham
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0303 health sciences ,Stromal cell ,biology ,T cell ,Cell ,T-cell receptor ,Major histocompatibility complex ,Immunological synapse ,Cell biology ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,medicine ,biology.protein ,Signal transduction ,Receptor ,030304 developmental biology ,030215 immunology - Abstract
The β-selection checkpoint of T cell development tests whether the cell has recombined its genomic DNA to produce a functional T Cell Receptor β (TCRβ) receptor. Passage through the β-selection checkpoint requires the nascent TCRβ protein to mediate signaling through a pre-TCR complex. In this study, we show that developing T cells at the β-selection checkpoint establish an immunological synapse in in vitro & in situ, resembling that of the mature T cell. The immunological synapse is dependent on two key signaling pathways known to be critical for the transition beyond the β-selection checkpoint, Notch and CXCR4 signaling. In vitro and in situ analyses indicate that the immunological synapse promotes passage through the β-selection checkpoint. Collectively, these data indicate that developing T cells regulate pre-TCR signaling through the formation of an immunological synapse. This signaling platform integrates cues from Notch, CXCR4, and MHC on the thymic stromal cell, to allow transition beyond the β-selection checkpoint.SummaryT cell development requires testing whether genomic rearrangement has produced a T cell receptor capable of transmitting signals. Most T cells fail this test. Here, we show that passage through the β-selection checkpoint requires assembly of a platform to support TCR signaling.
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- 2019
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14. A new role for Notch in the control of polarity and asymmetric cell division of developing T cells
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Mirren Charnley, Mandy J. Ludford-Menting, Sarah M. Russell, and Kim Pham
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Cell signaling ,Cell type ,Receptors, CXCR4 ,Cellular differentiation ,T cell ,T-Lymphocytes ,Beta selection ,Notch signaling pathway ,Nerve Tissue Proteins ,Cell Communication ,Biology ,Cell fate determination ,CXCR4 ,Cell Line ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Cell polarity ,medicine ,Asymmetric cell division ,Animals ,Humans ,Receptor, Notch1 ,Cells, Cultured ,030304 developmental biology ,Cell Proliferation ,0303 health sciences ,Cell Death ,Asymmetric Cell Division ,Cell Polarity ,Membrane Proteins ,Cell Differentiation ,Cell Biology ,Hematopoietic Stem Cells ,Cell biology ,Mice, Inbred C57BL ,Signalling ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,NUMB ,030217 neurology & neurosurgery ,Signal Transduction - Abstract
A fundamental question in biology is how single cells can reliably produce progeny of different cell types. Notch signalling frequently facilitates fate determination. Asymmetric cell division (ACD) often controls segregation of Notch signalling by imposing unequal inheritance of regulators of Notch. Here, we assessed the functional relationship between Notch and ACD in mouse T cell development. To attain immunological specificity, developing T cells must pass through a pivotal stage termed β-selection, which involves Notch signalling and ACD. We assessed functional interactions between Notch1 and ACD during β-selection through direct presentation of Notch ligands, DL1 and DL4, and pharmacological inhibition of Notch signalling. Contrary to prevailing models, we demonstrate that Notch signalling controls the distribution of Notch1 itself and cell fate determinants, α-adaptin and Numb. Furthermore, Notch and CXCR4 signalling cooperated to drive polarity during division. Thus, Notch signalling directly orchestrates ACD, and Notch1 is differentially inherited by sibling cells. This article has an associated First Person interview with the first author of the paper.
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- 2019
15. Separation of blood microsamples by exploiting sedimentation at the microscale
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Tatjana Sajic, Yanhui Liu, Marc Augsburger, Ruedi Aebersold, Julien Déglon, David Forchelet, Zoltan Pataky, Nasim Bararpour, Silke Grabherr, Steve Beguin, Miguel Frias, Philippe Renaud, Mirren Charnley, and Aurélien Thomas
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0301 basic medicine ,Proteomics ,Bioanalysis ,Sedimentation (water treatment) ,Microfluidics ,lcsh:Medicine ,Blood Sedimentation ,Cell Separation ,Article ,Clinical study ,03 medical and health sciences ,Humans ,Centrifugation ,Blood markers ,lcsh:Science ,Microscale chemistry ,ddc:613 ,ddc:616 ,ddc:615 ,Multidisciplinary ,Chromatography ,Chemistry ,Viscosity ,Blood separation ,ddc:614.1 ,lcsh:R ,Microfluidic Analytical Techniques ,Flow Cytometry ,030104 developmental biology ,lcsh:Q - Abstract
Microsample analysis is highly beneficial in blood-based testing where cutting-edge bioanalytical technologies enable the analysis of volumes down to a few tens of microliters. Despite the availability of analytical methods, the difficulty in obtaining high-quality and standardized microsamples at the point of collection remains a major limitation of the process. Here, we detail and model a blood separation principle which exploits discrete viscosity differences caused by blood particle sedimentation in a laminar flow. Based on this phenomenon, we developed a portable capillary-driven microfluidic device that separates blood microsamples collected from finger-pricks and delivers 2 µL of metered serum for bench-top analysis. Flow cytometric analysis demonstrated the high purity of generated microsamples. Proteomic and metabolomic analyses of the microsamples of 283 proteins and 1351 metabolite features was consistent with samples generated via a conventional centrifugation method. These results were confirmed by a clinical study scrutinising 8 blood markers in obese patients., Scientific Reports, 8, ISSN:2045-2322
- Published
- 2018
16. Asymmetric cell division during T cell development controls downstream fate
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Min Gu, Heather J. Melichar, Stephen B. Ting, David J. Izon, Edwin D. Hawkins, Carmen Molina-París, Raz Shimoni, Mandy J. Ludford-Menting, Patrick O. Humbert, Sarah M. Russell, Grant Lythe, Joseph Reynolds, Kim Pham, Kelly M Ramsbottom, Jane Oliaro, Mirren Charnley, and Ellen A. Robey
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Receptors, CXCR4 ,Time Factors ,Cellular differentiation ,T cell ,Beta selection ,Nerve Tissue Proteins ,Cell Communication ,Thymus Gland ,Biology ,Cell fate determination ,Transfection ,Article ,03 medical and health sciences ,Adaptor Protein Complex alpha Subunits ,0302 clinical medicine ,Cell polarity ,Asymmetric cell division ,medicine ,Animals ,Phosphorylation ,Cells, Cultured ,Protein Kinase C ,Research Articles ,Cell Proliferation ,030304 developmental biology ,Mice, Knockout ,0303 health sciences ,Thymocytes ,Cell Death ,Cell growth ,Asymmetric Cell Division ,Intracellular Signaling Peptides and Proteins ,Models, Immunological ,Cell Polarity ,Membrane Proteins ,Cell Differentiation ,Cell Biology ,Coculture Techniques ,Cell biology ,Mice, Inbred C57BL ,medicine.anatomical_structure ,Cellular Microenvironment ,NUMB ,Stromal Cells ,Signal Transduction ,030215 immunology - Abstract
T cell precursors undergo asymmetric cell division after T cell receptor genomic recombination, with stromal cell cues controlling the differential inheritance of fate determinants Numb and α-Adaptin by the daughters of a dividing DN3a T cell precursor., During mammalian T cell development, the requirement for expansion of many individual T cell clones, rather than merely expansion of the entire T cell population, suggests a possible role for asymmetric cell division (ACD). We show that ACD of developing T cells controls cell fate through differential inheritance of cell fate determinants Numb and α-Adaptin. ACD occurs specifically during the β-selection stage of T cell development, and subsequent divisions are predominantly symmetric. ACD is controlled by interaction with stromal cells and chemokine receptor signaling and uses a conserved network of polarity regulators. The disruption of polarity by deletion of the polarity regulator, Scribble, or the altered inheritance of fate determinants impacts subsequent fate decisions to influence the numbers of DN4 cells arising after the β-selection checkpoint. These findings indicate that ACD enables the thymic microenvironment to orchestrate fate decisions related to differentiation and self-renewal.
- Published
- 2015
17. Biomimetic topography and chemistry control cell attachment to amyloid fibrils
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Mirren Charnley, Marie N. Bongiovanni, Patrick G. Hartley, Sally L. Gras, and Nicholas P. Reynolds
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Amyloid ,Polymers and Plastics ,Biocompatible Materials ,Bioengineering ,Nanotechnology ,02 engineering and technology ,macromolecular substances ,Fibril ,Biomaterials ,Extracellular matrix ,Structure-Activity Relationship ,03 medical and health sciences ,Microscopy, Electron, Transmission ,Biomimetics ,Cell Adhesion ,Materials Chemistry ,Animals ,Humans ,Nanotopography ,Cell adhesion ,Nanoscopic scale ,030304 developmental biology ,chemistry.chemical_classification ,0303 health sciences ,Polymer ,Adhesion ,021001 nanoscience & nanotechnology ,Extracellular Matrix ,chemistry ,Peptides ,0210 nano-technology - Abstract
Networks of nanoscale fibrous coatings made from self-assembled peptides are promising candidates for biomaterials that can promote the growth of mammalian cells. One particularly attractive feature is the possibility of adding biofunctional sequences to peptides to promote cell attachment. We deconvolute the topographic and chemical effects of nanoscale fibrils on cells by depositing a plasma polymer film on TTR1-based fibrils decorated with a range of cell adhesive chemistries (RGD and cycloRGDfK), producing a surface that retains the nanoscale fibrous topography of surface-bound fibrils but lacks the fibril surface chemistry. The surface topography was found to influence cell toxicity and spreading, and the fibril surface chemistry influenced cell attachment and spreading. This study highlights the importance of considering both the chemical and physical features of novel biomaterials and illustrates the use of plasma polymer deposition as a tool for examining the relationship between amyloid fibril structure and function.
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- 2015
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18. Characterization of Amyloid Fibril Networks by Atomic Force Microscopy
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Mirren Charnley, Nicholas P. Reynolds, Jay Gilbert, and Owen G. Jones
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chemistry.chemical_classification ,Nanostructure ,Materials science ,Globular protein ,Strategy and Management ,Mechanical Engineering ,Metals and Alloys ,02 engineering and technology ,macromolecular substances ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Fibril ,01 natural sciences ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,Characterization (materials science) ,Extracellular matrix ,chemistry ,Cell culture ,Biophysics ,Methods Article ,0210 nano-technology ,Cell adhesion ,Amyloid (mycology) - Abstract
Dense networks of amyloid nanofibrils fabricated from common globular proteins adsorbed to solid supports can improve cell adhesion, spreading and differentiation compared to traditional flat, stiff 2D cell culture substrates like Tissue Culture Polystyrene (TCPS). This is due to the fibrous, nanotopographic nature of the amyloid fibril networks and the fact that they closely mimic the mechanical properties and architecture of the extracellular matrix (ECM). However, precise cell responses are strongly dependent on the nanostructure of the network at the cell culture interface, thus accurate characterization of the immobilized network is important. Due to its exquisite lateral resolution and simple sample preparation techniques, Atomic Force Microscopy (AFM) is an ideal technique to characterize the fibril network morphology. Thus, here we describe a detailed protocol, for the characterization of amyloid fibril networks by tapping mode AFM.
- Published
- 2017
19. Preparation of Amyloid Fibril Networks
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Mirren Charnley, Nicholas P. Reynolds, Owen G. Jones, and Jay Gilbert
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chemistry.chemical_classification ,Cell type ,Amyloid ,Globular protein ,Strategy and Management ,Mechanical Engineering ,Mesenchymal stem cell ,Metals and Alloys ,02 engineering and technology ,macromolecular substances ,Protein aggregation ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,chemistry ,Extracellular ,Biophysics ,Methods Article ,Stem cell ,0210 nano-technology ,Adult stem cell - Abstract
Networks of amyloid nanofibrils fabricated from common globular proteins such as lysozyme and β-lactoglobulin have material properties that mimic the extracellular microenvironment of many cell types. Cells cultured on such amyloid fibril networks show improved attachment, spreading and in the case of mesenchymal stem cells improved differentiation. Here we describe a detailed protocol for fabricating amyloid fibril networks suitable for eukaryotic cell culture applications.
- Published
- 2017
20. Quantifying Young's moduli of protein fibrils and particles with bimodal force spectroscopy
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Owen G. Jones, Nicholas P. Reynolds, Jay Gilbert, Christopher J. Cheng, and Mirren Charnley
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Nanostructure ,Materials science ,Mechanical Phenomena ,Zein ,General Physics and Astronomy ,Nanoparticle ,Modulus ,Nanotechnology ,02 engineering and technology ,Lactoglobulins ,engineering.material ,010402 general chemistry ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,Biomaterials ,Biopolymers ,General Materials Science ,Composite material ,chemistry.chemical_classification ,Spectrum Analysis ,Force spectroscopy ,General Chemistry ,Polymer ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Characterization (materials science) ,chemistry ,engineering ,Nanoparticles ,Biopolymer ,0210 nano-technology - Abstract
Force spectroscopy is a means of obtaining mechanical information of individual nanometer-scale structures in composite materials, such as protein assemblies for use in consumer films or gels. As a recently developed force spectroscopy technique, bimodal force spectroscopy relates frequency shifts in cantilevers simultaneously excited at multiple frequencies to the elastic properties of the contacted material, yet its utility for quantitative characterization of biopolymer assemblies has been limited. In this study, a linear correlation between experimental frequency shift and Young's modulus of polymer films was used to calibrate bimodal force spectroscopy and quantify Young's modulus of two protein nanostructures: β-lactoglobulin fibrils and zein nanoparticles. Cross-sectional Young's modulus of protein fibrils was determined to be 1.6 GPa while the modulus of zein nanoparticles was determined as 854 MPa. Parallel measurement of β-lactoglobulin fibril by a competing pulsed-force technique found a higher cross-sectional Young's modulus, highlighting the importance of comparative calibration against known standards in both pulsed and bimodal force spectroscopies. These findings demonstrate a successful procedure for measuring mechanical properties of individual protein assemblies with potential use in biological or packaging applications using bimodal force spectroscopy.
- Published
- 2017
21. Miniaturized pre-clinical cancer models as research and diagnostic tools
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Mirren Charnley, Edna Cukierman, and Maria Håkanson
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Biomedical Research ,VEGF receptors ,Cancer drugs ,Drug Evaluation, Preclinical ,Pharmaceutical Science ,Antineoplastic Agents ,Nanotechnology ,Biology ,Diagnostic tools ,Models, Biological ,Article ,03 medical and health sciences ,0302 clinical medicine ,Neoplasms ,Drug Discovery ,Tumor Microenvironment ,medicine ,Animals ,Humans ,030304 developmental biology ,0303 health sciences ,Miniaturization ,Drug discovery ,Cancer ,Microfluidic Analytical Techniques ,medicine.disease ,3. Good health ,Drug development ,Risk analysis (engineering) ,030220 oncology & carcinogenesis ,biology.protein ,Treatment strategy - Abstract
Cancer is one of the most common causes of death worldwide. Consequently, important resources are directed towards bettering treatments and outcomes. Cancer is difficult to treat due to its heterogeneity, plasticity and frequent drug resistance. New treatment strategies should strive for personalized approaches. These should target neoplastic and/or activated microenvironmental heterogeneity and plasticity without triggering resistance and spare host cells. In this review, the putative use of increasingly physiologically relevant microfabricated cell-culturing systems intended for drug development is discussed. There are two main reasons for the use of miniaturized systems. First, scaling down model size allows for high control of microenvironmental cues enabling more predictive outcomes. Second, miniaturization reduces reagent consumption, thus facilitating combinatorial approaches with little effort and enables the application of scarce materials, such as patient-derived samples. This review aims to give an overview of the state-of-the-art of such systems while predicting their application in cancer drug development.
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- 2014
- Full Text
- View/download PDF
22. Bacterial biofilm formation versus mammalian cell growth on titanium-based mono- and bi-functional coating
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Mirren Charnley, Marcus Textor, Bidhari Pidhatika, Henk J. Busscher, Géraldine Coullerez, Henny C. van der Mei, Guruprakash Subbiahdoss, Roel Kuijer, University of Groningen, Man, Biomaterials and Microbes (MBM), Personalized Healthcare Technology (PHT), and Restoring Organ Function by Means of Regenerative Medicine (REGENERATE)
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polymer brush ,Modern medicine ,lcsh:Diseases of the musculoskeletal system ,PROTEIN ADSORPTION ,OXIDE SURFACES ,lcsh:Surgery ,Context (language use) ,Bacterial Adhesion ,biofilm ,Polyethylene Glycols ,Microbiology ,chemistry.chemical_compound ,Coated Materials, Biocompatible ,Materials Testing ,INFECTION ,PEG ratio ,Cell Adhesion ,Staphylococcus epidermidis ,Animals ,PEPTIDE ,U2OS osteoblast ,MICROBIAL ADHESION ,OSTEOBLAST ,Cell Proliferation ,Titanium ,Infection Control ,polyethylene glycol brush coating ,Osteoblasts ,Tissue Engineering ,TISSUE INTEGRATION ,GLYCOL) COPOLYMERS ,Biomaterials-associated infections ,technology, industry, and agriculture ,Biofilm ,lcsh:RD1-811 ,non-adhesive fouling ,Adhesion ,Titanium oxide ,chemistry ,Chemical engineering ,Biofilms ,STAPHYLOCOCCUS-EPIDERMIDIS ,lcsh:RC925-935 ,Oligopeptides ,Ethylene glycol ,RESISTANCE ,Protein adsorption - Abstract
Biomaterials-associated-infections (BAI) are serious complications in modern medicine. Although non-adhesive coatings, like polymer-brush coatings, have been shown to prevent bacterial adhesion, they do not support cell growth. Bi-functional coatings are supposed to prevent biofilm formation while supporting tissue integration. Here, bacterial and cellular responses to poly(ethylene glycol) (PEG) brush-coatings on titanium oxide presenting the integrin-active peptide RGD (arginine-glycine-aspartic acid) (bioactive "PEG-RGD") were compared to monofunctional PEG brush-coatings (biopassive "PEG") and bare titanium oxide (TiO(2)) surfaces under flow. Staphylococcus epidermidis ATCC 35983 was deposited on the surfaces under a shear rate of 11 s(-1) for 2 h followed by seeding of U2OS osteoblasts. Subsequently, both S. epidermidis and U2OS cells were grown simultaneously on the surfaces for 48 h under low shear (0.14 s(-1)). After 2 h, staphylococcal adhesion was reduced to 3.6 +/- 1.8 x 10(3) and 6.0 +/- 3.9 x 10(3) cm(-2) on PEG and PEG-RGD coatings respectively, compared to 1.3 +/- 0.4 x 10(5) cm(-2) for the TiO(2) surface. When allowed to grow for 48 h, biofilms formed on all surfaces. However, biofilms detached from the PEG and PEG-RGD coatings when exposed to an elevated shear (5.6 s(-1)). U2OS cells neither adhered nor spread on PEG brush-coatings, regardless of the presence of biofilm. In contrast, in the presence of biofilm, U2OS cells adhered and spread on PEG-RGD coatings with a significantly higher surface coverage than on bare TiO(2). The detachment of biofilm and the high cell surface coverage revealed the potential significance of PEG-RGD coatings in the context of the "race for the surface" between bacteria and mammalian cells.
- Published
- 2010
23. Osteogenic differentiation of human mesenchymal stem cells in the absence of osteogenic supplements: A surface-roughness gradient study
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Nuno M. Neves, Ana B. Faia-Torres, Mirren Charnley, Markus Rottmar, Marcus Textor, Tolga Goren, Katharina Maniura-Weber, Stefanie Guimond-Lischer, Nicholas D. Spencer, Rui L. Reis, and Universidade do Minho
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Materials science ,Surface Properties ,Cellular differentiation ,Polyesters ,Biomedical Engineering ,Biocompatible Materials ,02 engineering and technology ,Biochemistry ,Regenerative medicine ,High-throughput screening (gradient) ,Biomaterials ,03 medical and health sciences ,chemistry.chemical_compound ,Tissue engineering ,Osteogenesis ,Bone cell ,Humans ,Molecular Biology ,030304 developmental biology ,Aged ,0303 health sciences ,Science & Technology ,Mesenchymal stem cell ,Cell Differentiation ,Mesenchymal Stem Cells ,General Medicine ,021001 nanoscience & nanotechnology ,Culture Media ,chemistry ,Polycaprolactone ,Mesenchymal stem cells ,Alkaline phosphatase ,Mesenchymal stem cell differentiation ,Microstructures ,0210 nano-technology ,Biotechnology ,Biomedical engineering - Abstract
The use of biomaterials to direct osteogenic differentiation of human mesenchymal stem cells (hMSCs) in the absence of osteogenic supplements is thought to be part of the next generation of orthopedic implants. We previously engineered surface-roughness gradients of average roughness (Ra) varying from the sub-micron to the micrometer range ( 0.5–4.7 lm), and mean distance between peaks (RSm) gradually varying from 214 lm to 33 lm. Here we have screened the ability of such surface-gradients of polycaprolactone to influence the expression of alkaline phosphatase (ALP), collagen type 1 (COL1) and mineralization by hMSCs cultured in dexamethasone (Dex)-deprived osteogenic induction medium (OIM) and in basal growth medium (BGM). Ra 1.53 lm/RSm 79 lm in Dex-deprived OI medium, and Ra 0.93 lm/RSm 135 lm in BGM consistently showed higher effectiveness at supporting the expression of the osteogenic markers ALP, COL1 and mineralization, compared to the tissue culture polystyrene (TCP) control in complete OIM. The superior effectiveness of specific surface-roughness revealed that this strategy may be used as a compelling alternative to soluble osteogenic inducers in orthopedic applications featuring the clinically relevant biodegradable polymer polycaprolactone., This work was supported by the Foundation for Science and Technology for the PhD Grant of A.B. Faia-Torres (SFRH/BD/36476/2007). We are also grateful to the Swiss National Science Foundation (SNSF) Grant P300P3_154664 for providing funds to MC.
- Published
- 2015
24. Regulation of human mesenchymal stem cell osteogenesis by specific surface density of fibronectin: a gradient study
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Mirren Charnley, Ana B. Faia-Torres, Tolga Goren, Markus Rottmar, Katharina Maniura-Weber, Rui L. Reis, Nuno M. Neves, Nicholas D. Spencer, Stefanie Guimond-Lischer, Marcus Textor, Teemu O. Ihalainen, and Universidade do Minho
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Materials science ,Engenharia e Tecnologia::Biotecnologia Industrial ,Polyesters ,Bone Marrow Cells ,Biomaterials ,chemistry.chemical_compound ,Biotecnologia Médica [Ciências Médicas] ,Osteogenesis ,Biotecnologia Industrial [Engenharia e Tecnologia] ,ComputingMilieux_COMPUTERSANDEDUCATION ,Humans ,General Materials Science ,Cytoskeleton ,Fibronectin ,Cells, Cultured ,Cell Proliferation ,Science & Technology ,biology ,Mesenchymal stem cell ,Cell Differentiation ,Alkaline Phosphatase ,Fibronectins ,Cell biology ,Collagen, type I, alpha 1 ,chemistry ,Polycaprolactone ,biology.protein ,Ciências Médicas::Biotecnologia Médica ,Immunohistochemistry ,Alkaline phosphatase ,Mesenchymal stem cells ,Collagen ,Gradient ,Stem cell - Abstract
The success of synthetic bone implants requires good interface between the material and the host tissue. To study the biological relevance of fi bronectin (FN) density on the osteogenic commitment of human bone marrow mesenchymal stem cells (hBMMSCs), human FN was adsorbed in a linear density gradient on the surface of PCL. The evolution of the osteogenic markers alkaline phosphatase and collagen 1 alpha 1 was monitored by immunohistochemistry, and the cytoskeletal organization and the cell-derived FN were assessed. The functional analysis of the gradient revealed that the lower FN-density elicited stronger osteogenic expression and higher cytoskeleton spreading, hallmarks of the stem cell commitment to the osteoblastic lineage. The identifi cation of the optimal FN density regime for the osteogenic commitment of hBM-MSCs presents a simple and versatile strategy to signifi cantly enhance the surface properties of polycaprolactone as a paradigm for other synthetic polymers intended for bone-related applications., This work was supported by the Foundation for Science and Technology for the PhD grant of A.B. Faia-Torres (SFRH/BD/36476/2007). We are also grateful to the Swiss National Science foundation (SNSF) grant P300P3_154664 for providing funds to MC.
- Published
- 2015
25. pH-dependent lipid vesicle interactions with plasma polymerized thin films
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Mirren Charnley, Hannah J. Askew, Sally L. McArthur, and Karyn L. Jarvis
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Plasma Gases ,In Focus: Biointerface Science and Engineered Biomaterials - An Issue in Honor of Professor Buddy Ratner's 70th Birthday ,Lipid Bilayers ,Analytical chemistry ,General Physics and Astronomy ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,Allylamine ,Biomaterials ,Cell membrane ,chemistry.chemical_compound ,Adsorption ,medicine ,General Materials Science ,Lipid bilayer ,chemistry.chemical_classification ,Chemistry ,Vesicle ,General Chemistry ,Buffer solution ,Polymer ,Quartz crystal microbalance ,Hydrogen-Ion Concentration ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,medicine.anatomical_structure ,Acrylates ,Polymerization ,Biophysics ,0210 nano-technology - Abstract
Model lipid vesicle and supported lipid bilayer (SLB) systems are used in a variety of applications including biosensing, cell membrane mimics, and drug delivery. Exposure of a surface to a vesicle solution provides a straightforward method for creating such systems via vesicle adsorption and collapse. However, this process is complex and the relationship between the surface physicochemical properties and vesicle collapse is poorly understood. Plasma polymers are thin conformal films that can be applied to a variety of materials to modify surface properties. This paper uses quartz crystal microbalance with dissipation and fluorescence recovery after photobleaching (FRAP) to explore lipid vesicle interactions with plasma polymerized acrylic acid (ppAAc), allylamine (ppAAm), and ppAAc/ppAAm micropatterns. Vesicle interactions were dependent on plasma polymer chemistry and pH of the buffer solution. Vesicles readily and stably adsorbed to ppAAm over a wide pH range. ppAAc demonstrated limited interactions at pH 7 and vesicle adsorption at pH 4. Vesicle collapse and SLB formation could be induced using a pH change. FRAP was used to explore the fluidity of the lipid structures on both the patterned and unpatterned plasma polymer films. On ppAAm/ppAAc micropatterns, pH transitions combined with the presence of chemically distinct regions on the same substrate enabled immobile lipid islands on ppAAc to be surrounded by fluid lipid regions on ppAAm. This work demonstrates that plasma polymer films could enable spatially controlled vesicle adsorption and SLB formation on a wide variety of different substrates.
- Published
- 2017
26. Substrate Adhesion Regulates Sealing Zone Architecture and Dynamics in Cultured Osteoclasts
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Peter Horvath, Fabian Anderegg, Dafna Geblinger, Mirren Charnley, Marcus Textor, Lia Addadi, and Benjamin Geiger
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Integrins ,Podosome ,Cell Culture Techniques ,lcsh:Medicine ,Osteoclasts ,Matrix (biology) ,Biochemistry ,Polyethylene Glycols ,Mice ,0302 clinical medicine ,Molecular Cell Biology ,Polylysine ,lcsh:Science ,Cytoskeleton ,Cells, Cultured ,0303 health sciences ,Multidisciplinary ,Laboratory glassware ,Microscopy, Video ,biology ,Chemistry ,Cell Differentiation ,Adhesion ,Vinculin ,Immunohistochemistry ,Cellular Structures ,Cell biology ,Extracellular Matrix ,Actin Cytoskeleton ,030220 oncology & carcinogenesis ,Cytochemistry ,Microtechnology ,Medicine ,Research Article ,Surface Properties ,Bone and Mineral Metabolism ,Materials Science ,Bone and Bones ,Cell Line ,Biomaterials ,03 medical and health sciences ,Rheumatology ,Cell Adhesion ,Animals ,Vitronectin ,Cell adhesion ,Biology ,Extracellular Matrix Adhesions ,030304 developmental biology ,lcsh:R ,Proteins ,Actin cytoskeleton ,Cytoskeletal Proteins ,Metabolism ,Microscopy, Fluorescence ,biology.protein ,lcsh:Q ,Glass ,Stress, Mechanical - Abstract
The bone-degrading activity of osteoclasts depends on the formation of a cytoskeletal-adhesive super-structure known as the sealing zone (SZ). The SZ is a dynamic structure, consisting of a condensed array of podosomes, the elementary adhesion-mediating structures of osteoclasts, interconnected by F-actin filaments. The molecular composition and structure of the SZ were extensively investigated, yet despite its major importance for bone formation and remodelling, the mechanisms underlying its assembly and dynamics are still poorly understood. Here we determine the relations between matrix adhesiveness and the formation, stability and expansion of the SZ. By growing differentiated osteoclasts on micro-patterned glass substrates, where adhesive areas are separated by non-adhesive PLL-g-PEG barriers, we show that SZ growth and fusion strictly depend on the continuity of substrate adhesiveness, at the micrometer scale. We present a possible model for the role of mechanical forces in SZ formation and reorganization, inspired by the current data., PLoS ONE, 6 (12), ISSN:1932-6203
- Published
- 2011
27. Controlled breast cancer microarrays for the deconvolution of cellular multilayering and density effects upon drug responses
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Mirren Charnley, Marcus Textor, Stefan Kobel, Matthias P. Lutolf, Maria Håkanson, and Edna Cukierman
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Integrins ,Resistance ,lcsh:Medicine ,Apoptosis ,Cell Count ,Pharmacology ,medicine.disease_cause ,Hydrogel, Polyethylene Glycol Dimethacrylate ,Polyethylene Glycols ,0302 clinical medicine ,Drug Discovery ,Molecular Cell Biology ,Breast Tumors ,Basic Cancer Research ,Tumor Cells, Cultured ,Tumor Microenvironment ,Biological Systems Engineering ,lcsh:Science ,0303 health sciences ,Multidisciplinary ,Cell Death ,Integrin beta1 ,Cell Cycle ,Beta(1) Integrin ,Cell cycle ,Cadherins ,Extracellular-Matrix ,3. Good health ,Cell biology ,Extracellular Matrix ,Oncology ,030220 oncology & carcinogenesis ,Tissue Architecture ,Medicine ,Female ,DNA microarray ,Research Article ,Biotechnology ,Paclitaxel ,Cells ,Materials Science ,Down-Regulation ,Breast Neoplasms ,Bioengineering ,Biology ,Biomaterials ,03 medical and health sciences ,Breast cancer ,In vivo ,Prognostic Marker ,medicine ,Cell Adhesion ,Humans ,Extracellular Matrix Adhesions ,030304 developmental biology ,Cell Proliferation ,Tumor microenvironment ,lcsh:R ,Cancer ,Cancers and Neoplasms ,medicine.disease ,Kinase Inhibitor P27(Kip1) ,Anticancer Drugs ,In-Vitro ,Tumor progression ,Drug Resistance, Neoplasm ,Tumor Progression ,lcsh:Q ,Carcinogenesis - Abstract
Background Increasing evidence shows that the cancer microenvironment affects both tumorigenesis and the response of cancer to drug treatment. Therefore in vitro models that selectively reflect characteristics of the in vivo environment are greatly needed. Current methods allow us to screen the effect of extrinsic parameters such as matrix composition and to model the complex and three-dimensional (3D) cancer environment. However, 3D models that reflect characteristics of the in vivo environment are typically too complex and do not allow the separation of discrete extrinsic parameters. Methodology/Principal Findings In this study we used a poly(ethylene glycol) (PEG) hydrogel-based microwell array to model breast cancer cell behavior in multilayer cell clusters that allows a rigorous control of the environment. The innovative array fabrication enables different matrix proteins to be integrated into the bottom surface of microwells. Thereby, extrinsic parameters including dimensionality, type of matrix coating and the extent of cell-cell adhesion could be independently studied. Our results suggest that cell to matrix interactions and increased cell-cell adhesion, at high cell density, induce independent effects on the response to Taxol in multilayer breast cancer cell clusters. In addition, comparing the levels of apoptosis and proliferation revealed that drug resistance mediated by cell-cell adhesion can be related to altered cell cycle regulation. Conversely, the matrix-dependent response to Taxol did not correlate with proliferation changes suggesting that cell death inhibition may be responsible for this effect. Conclusions/Significance The application of the PEG hydrogel platform provided novel insight into the independent role of extrinsic parameters controlling drug response. The presented platform may not only become a useful tool for basic research related to the role of the cancer microenvironment but could also serve as a complementary platform for in vitro drug development. ISSN:1932-6203
- Published
- 2011
28. Integration column: microwell arrays for mammalian cell culture
- Author
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Ali Khademhosseini, Matthias P. Lutolf, Marcus Textor, and Mirren Charnley
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System ,Cell ,Cell Culture Techniques ,Biophysics ,Cell fate determination ,Biology ,Biochemistry ,Single-Cell ,medicine ,Animals ,Humans ,Embryonic Stem-Cells ,Progenitor cell ,Cell shape ,Microfluidic Channels ,E-Cadherin ,Cell growth ,Stem Cells ,Cell Differentiation ,Hydrogels ,Hematopoietic Stem ,Embryonic stem cell ,Cell biology ,Surface ,Poly(Ethylene Glycol) Photolithography ,medicine.anatomical_structure ,Cell culture ,Differentiation ,3D ,Microfabrication - Abstract
Microwell arrays have emerged as robust and versatile alternatives to conventional mammalian cell culture substrates. Using standard microfabrication processes, biomaterials surfaces can be topographically patterned to comprise high-density arrays of micron-sized cavities with desirable geometry. Hundreds to thousands of individual cells or cell colonies with controlled size and shape can be trapped in these cavities by simple gravitational sedimentation. Efficient long-term cell confinement allows for parallel analyses and manipulation of cell fate during in vitro culture. These live-cell arrays have already found applications in cell biology, for example to probe the effect of cell colony size on embryonic stem cell differentiation, to dissect the heterogeneity in single cell proliferation kinetics of neural or hematopoietic stem/progenitor cell populations, or to elucidate the role of cell shape on cell function. Here, we highlight the key applications of these platforms, hopefully inspiring biologists to apply these systems for their own studies.
- Published
- 2009
29. Development of an lbuprofen-Releasing Biodegradable PLA/PGA Electrospun Scaffold for Tissue Regeneration
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Calogero Fiorica, Keith A. Blackwood, Mirren Charnley, Anthony J. Ryan, Robert McKean, Irene Canton, Sheila MacNeil, Canton, I, Mckean, R, Charnley, M, Blackwood, KA, Fiorica, C, Ryan, AJ, and MacNeil, S.
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Keratinocytes ,Scaffold ,Polyglycolide ,Polyesters ,wound healing ,Bioengineering ,Biocompatible Materials ,Ibuprofen ,biodegradation ,Applied Microbiology and Biotechnology ,chemistry.chemical_compound ,Tissue engineering ,medicine ,Cell Adhesion ,Humans ,drug release ,Cells, Cultured ,Cell Proliferation ,Tissue Engineering ,Tissue Scaffolds ,Chemistry ,organic chemicals ,Regeneration (biology) ,Anti-Inflammatory Agents, Non-Steroidal ,Fibroblasts ,PLGA ,inflammation ,Settore CHIM/09 - Farmaceutico Tecnologico Applicativo ,Delayed-Action Preparations ,Liberation ,Wound healing ,Polyglycolic Acid ,Biotechnology ,Biomedical engineering ,medicine.drug - Abstract
Our aim was to develop a biodegradable fibrous dressing to act as a tissue guide for in situ wound repair while releasing Ibuprofen to reduce inflammation in wounds and reduce pain for patients on dressing changes. Dissolving the acid form of Ibuprofen (from 1% to 10% by weight) in the same solvent as 75% polylactide, 25% polyglycolide (PLGA) polymers gave uniformly loaded electrospun fibers which gave rapid release of drug within the first 8 h and then slower release over several days. Scaffolds with 10% Ibuprofen degraded within 6 days. The Ibuprofen released from these scaffolds significantly reduced the response of fibroblasts to major pro-inflammatory stimulators. Fibroblast attachment and proliferation on scaffolds was unaffected by the addition of 1-5% Ibuprofen. Scaffolds loaded with 10% Ibuprofen initially showed reduced cell attachment but this was restored by soaking scaffolds in media for 24 h. In summary, addition of Ibuprofen to electrospun biodegradable scaffolds can give acute protection of adjacent cells to inflammation while the scaffolds provide an open 3D fibrous network to which cells can attach and migrate. By 6 days, such scaffolds will have completely dissolved into the wound bed obviating any need for dressing removal.
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