Tensegrity cellular researchers always contended, the tension components are both structural and bio-informatic, meaning that they signal critical information. The tiny, silly-putty-like rods in the photo were proven to signal stem cell growth patterns. This is important experimental proof that some inter-cellular communication happens using tensions between cells. The work was done at McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia. From the abstract:
Stem cells transit along a variety of lineage-specific routes towards differentiated phenotypes. These fate decisions are dependent not just on the soluble chemical cues that are encountered or enforced in vivo and in vitro, but also on physical cues from the cellular microenvironment. These physical cues can consist of both nano- and micro-scale topographical features, as well as mechanical inputs provided passively (from the base properties of the materials to which they are adhered) or actively (from extrinsic applied mechanical deformations). A suitable tool for investigating the coordination of these cues lies in nanofibrous scaffolds, which can both dictate cellular and cytoskeletal orientation, and facilitate mechanical perturbations to seeded cells. Here, we demonstrate a coordinated influence of scaffold architecture (aligned versus randomly organized fibers) and tensile deformation on nuclear shape and orientation. Sensitivity of nuclear morphology to scaffold architecture was more pronounced in stem cell populations than in terminally differentiated fibrochondrocytes. Tension applied to the scaffold elicited further alterations in nuclear morphology, greatest in stem cells, that were mediated by the filamentous actin cytoskeleton, but not the microtubule or intermediate filament network. With loading, nuclear perturbations were time- and direction-dependent, suggesting that the modality and direction of loading influence nuclear architecture. The present work may provide additional insight into the mechanisms by which the physical microenvironment influences cell fate decisions, and has specific application to the design of new materials for regenerative medicine applications with adult stem cells.
Credit:
Hats off to http://holykaw.alltop.com/silly-putty-scaffold-sizes-up-stem-cells for posting this first, and to Mr. Floating Bones Phil Earnhardt himself for bringing it to my attention.
Citation:
Mechano-topographic modulation of stem cell nuclear shape on nanofibrous scaffolds. by Ashwin S. Nathan, Brendon M. Baker, Nandan L. Nerurkar, Robert L. Mauck. Acta Biomaterialia, In Press, Accepted Manuscript,
Available online 13 August 2010, ISSN 1742-7061, DOI: 10.1016/j.actbio.2010.08.007.
Keywords: Mesenchymal stem cells; nanofibers; nuclear orientation; anisotropy; cytoskeleton
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