Scroll
Featured
Hypertension, exercise, and pregnancy are common triggers of cardiac remodeling, which occurs primarily through the hypertrophy of individual cardiomyocytes. During hypertrophy, stress-induced signal transduction increases cardiomyocyte transcription and translation, which promotes the addition of new contractile units through poorly understood mechanisms. The cardiomyocyte microtubule network is also implicated in hypertrophy, but via an unknown role. Here, we show that microtubules are indispensable for cardiac growth via spatiotemporal control of the translational machinery. We find that the microtubule motor Kinesin-1 distributes mRNAs and ribosomes along microtubule tracks to discrete domains within the cardiomyocyte. Upon hypertrophic stimulation, microtubules redistribute mRNAs and new protein synthesis to sites of growth at the cell periphery. If the microtubule network is disrupted, mRNAs and ribosomes collapse around the nucleus, which results in mislocalized protein synthesis, the rapid degradation of new proteins, and a failure of growth, despite normally increased translation rates. Together, these data indicate that mRNAs and ribosomes are actively transported to specific sites to facilitate local translation and assembly of contractile units, and suggest that properly localized translation – and not simply translation rate – is a critical determinant of cardiac hypertrophy.
Originally Published in: Nature Communications (2021) (Link to Paper)
This study confirmed that focal adhesions transduce physical signals from topographical cues in the ECM into changes in cellular migration. Also, that aligned collagen organization induced myofibroblast differentiation, with a concomitant upregulation in myofibroblast-specific ECM genes like Postn and FnEDa.
Source: Darrian Bugg, Ross Bretherton, Peter Kim, Emily Olszewski, Abigail Nagle, Austin E. Schumacher, Nick Chu, Jagadambika Gunaje, Cole A. DeForest, Kelly Stevens, Deok-Ho Kim, Jennifer Davis. Infarct Collagen Topography Regulates Fibroblast Fate via p38-Yes-Associated Protein Transcriptional Enhanced Associate Domain Signals. Circulation Research, October 2020 (Link to Paper)
A Live Cell Reporter of Exosome Secretion and Uptake Reveals Pathfinding Behavior of Migrating Cells
Small extracellular vesicles called exosomes affect multiple autocrine and paracrine cellular phenotypes and this study reports on a new fluorescent tool that allows for live imaging of cell migration. Researchers used this tool to visualize secreted exosomes in 3D culture and in vivo and identify a role for exosomes in promoting leader–follower behavior in 2D and 3D migration. Growing their cultures on nanopatterned plates allowed easy visualization of whether exosomes were secreted from the front or back of migrating cells, something impossible to determine on standard tissue culture plates. This new tool can now be used to understand a wide variety of roles for exosomes across tissue types.
Originally Published in: Nature Communications (2020) (Link to Paper)
This publication demonstrates that cells can transmit forces by coupling the retrograde flow of actin to a geometrically irregular environment, and that this can happen in the complete absence of any transmembrane receptors that link the cytoskeleton to the substrate.
Source: Reversat, A., Gaertner, F., Merrin, J. et al. Cellular locomotion using environmental topography. Nature 582, 582–585 (2020). (Link to Paper)
This study demonstarted that the mechanical tension across cell surface proteins is responsive to changes in substrate stiffness, nanotopographical cues and to fluidic shear stresses. Moreover, it showed that these mechanical stimuli cause alterations in the association of cell surface proteins with cytoskeletal and focal adhesion-related signaling pathways.
Source: (Link to Paper)
Source: Heffler J, Shah PP, Robison P, et al. A Balance Between Intermediate Filaments and Microtubules Maintains Nuclear Architecture in the Cardiomyocyte. Circ Res. 126(3):e10–e26, Publication Date: 2020 (Link to Paper)
This publication demonstrates that nanopatterned and ion permeable polymer‐coated electrodes can be utilized for enhancing the cellular environment of excitable cells within electrode‐based assays.
Source: (Link to Paper)
Developed a novel method for patterning and layering individual cell sheets and casting them into 3D tubular geometries with curved surfaces.
The integrity of the expanding epithelial sheets depends on extracellular cues, including cell-cell and cell-matrix interactions. Researchers show that the nano-scale topography of the extracellular matrix underlying epithelial cell layers can strongly affect the speed and morphology of the fronts of the expanding sheet which is dependent on expression of the transcription factor YAP. This process is integral to epithelial to mesenchymal transitions which is a key stage of cancer progression and metastasis.
Originally Published in: Nature Communications (2019) (Link to Paper)
Alec S. T. Smith, Eunpyo Choi, Kevin Gray, Jesse Macadangdang, Eun Hyun Ahn, Elisa C. Clark, Michael A. Laflamme, Joseph C. Wu, Charles E. Murry, Leslie Tung, Deok-Ho Kim* Nano Lett. 2020, vol. 20, no. 3, pp. 1561-1570, Publication Date: December 17, 2019 (Link to Paper)
Kshitiz, Afzal, J., Maziarz, J.D. et al. Nat Ecol Evol 3, pp. 1743–1753, Publication Date: 2019 (Link to Paper)
This study aims to elucidate the role of cell adhesion to the extracellular matrix plays in maintenance of pluripotency. Researchers used superresolution two-color interferometric photo-activated localization microscopy to examine the three-dimensional architecture of cornerstone adhesions and report vertical lamination of FA proteins. Nanopatterned plates were used to accelerate differentiation of stem cell cultures to help examine the roles of these structural elements.
Originally Published in: Nature Communications (2019) (Link to Paper)
Recreation of a muscle that can be controlled by the nervous system would provide a major breakthrough for treatments of injury and diseases. However, the underlying basis of how neuron–muscle interfaces are formed is still not understood sufficiently. Here, it is hypothesized that substrate topography regulates neural innervation and synaptic transmission by mediating the cross-talk between neurons and muscles. This hypothesis is examined by differentiating neural stem cells on the myotubes, formed on the substrate with controlled groove width. The substrate with the groove width of 1600 nm, a similar size to the myofibril diameter, serves to produce larger and aligned myotubes than the flat substrate. The myotubes formed on the grooved substrate display increases in the acetylcholine receptor expression. Reciprocally, motor neuron progenitor cells differentiated from neural stem cells innervate the larger and aligned myotubes more actively than randomly oriented myotubes. The results of this study will be broadly useful for improving the quality of engineered muscle used in a series of applications including drug screening, regeneration therapies, and biological machinery assembly.
Originally Published in: Advanced Science (2019) (Link to Paper)
Bong Hwan Sung, Roxanne Pelletier, Alissa M. Weaver, bioRxiv 577346, Publication Date: 2019 (Link to Paper)
Cancer cell migration through and away from tumors is driven in part by migration along aligned extracellular matrix, a process known as contact guidance (CG). To concurrently study the influence of architectural and mechanical regulators of CG sensing, we developed a set of CG platforms. Using flat and nanotextured substrates with variable architectures and stiffness, we show that CG sensing is regulated by substrate stiffness and define a mechanical role for microtubules and actomyosin-microtubule interactions during CG sensing. Furthermore, we show that Arp2/3-dependent lamellipodia dynamics can compete with aligned protrusions to diminish the CG response and define Arp2/3- and Formins-dependent actin architectures that regulate microtubule-dependent protrusions, which promote the CG response. Thus, our work represents a comprehensive examination of the physical mechanisms influencing CG sensing.
Originally Published in: Cell Reports (2018) (Link to Paper)
Kim, D., Ewald, A.J., Park, J. et al. Sci Rep 8, 14210, Publication Date: 2018 (Link to Paper)
Jonathan H. Tsui et al. J. Mater. Chem. B, 6, 7185-7196, Publication Date: 2018 (Link To Paper)
Joong-Hyun Kim et al. J Periodontal Implant Sci. , 47(6): 402–415, Publication Date: December 2017 (Link To Paper)
Jonathan H. Tsui et al. ACS Nano, 11, 12, 11954-11968, Publication Date: November 20, 2017 (Link To Paper)
Li, Linfeng & LaBarbera, D.V. 10.1016/B978-0-12-409547-2.12329-7., Publication Date: 2016 (Link To Paper)
Ray, A., Lee, O., Win, Z. et al. Nat Commun 8, 14923, Publication Date: 2017 (Link To Paper)
Source: Nisa P. Williams, Marcus Rhodehamel, Calysta Yan, Alec S.T. Smith, Alex Jiao, Charles E. Murry, Marta Scatena, Deok-Ho Kim, Engineering anisotropic 3D tubular tissues with flexible thermoresponsive nanofabricated substrates, Biomaterials, Volume 240, 2020, 119856, ISSN 0142-9612.
(Link to Paper)
Kshitiz, Junaid Afzal, Sang-Yeob Kim & Deok-Ho Kim, Cell Adhesion & Migration, 9:4, 300-307, DOI, Publication Date: 2015 (Link To Paper)
Hyeona Jeon et al. ACS Appl. Mater. Interfaces 2015, 7, 8, 4525-4532, Publication Date: February 6, 2015 (Link To Paper)
Cameron L. Nemeth et al. Tissue Engineering Part A VOL. 20, NO. 21-22, Publication Date: 25 Jun 2014 (Link To Paper)
Peter Kim et al. Biofabrication, Volume 6, Number 2, Date Published: 10 April 2014 (Link To Paper)
Alex Jiao et al. ACS Nano 2014, 8, 5, 4430-4439, Publication Date: March 15, 2014 (Link To Paper)
The integration of nanotopographic patterns with hiPSC-CM culture have been shown to induce structural and phenotypic development of hiPSC-CM monolayers by enhancing cytoskeletal organization and cellular alignment and providing greater sensitivity to conduction-blocking compounds and overall dose-response relationships (Carson et al., 2016; Smith et al., 2020). The NanoSurface platform by Curi Bio (Seattle, WA) can be used as a versatile platform for enhancing the structural development of cells and improving their physiological relevance in disease modeling. Culturing hiPSC-CMs on nanopatterned 25-mm coverslips (e.g., Curi Bio ANFSCS25) placed in a 6-well plate may facilitate the development of CPVT-specific cell morphology characteristics related to dyadic ultrastructure and contractile function through hiPSC-CM maturation.
Originally Published in: Current Protocols (2021) (Link to Paper)