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Nanofibrillar scaffolds induce preferential activation of Rho GTPases in cerebral cortical astrocytes

Authors Tiryaki VM, Ayres, Khan, Ahmed, Shreiber, Meiners

Received 6 April 2012

Accepted for publication 31 May 2012

Published 20 July 2012 Volume 2012:7 Pages 3891—3905


Review by Single anonymous peer review

Peer reviewer comments 5

Volkan Mujdat Tiryaki,1 Virginia M Ayres,1 Adeel A Khan,2 Ijaz Ahmed,3 David I Shreiber,3 Sally Meiners4

1Electronic and Biological Nanostructures Laboratory, Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI, USA; 2Department of Paper Engineering, Chemical Engineering, Imaging, Western Michigan University, Kalamazoo, MI, USA; 3Department of Biomedical Engineering, Rutgers, The State University of New Jersey, Piscataway, NJ, USA; 4Nanoculture, LLC, Piscataway, NJ, USA

Abstract: Cerebral cortical astrocyte responses to polyamide nanofibrillar scaffolds versus poly-L-lysine (PLL)-functionalized planar glass, unfunctionalized planar Aclar coverslips, and PLL-functionalized planar Aclar surfaces were investigated by atomic force microscopy and immunocytochemistry. The physical properties of the cell culture environments were evaluated using contact angle and surface roughness measurements and compared. Astrocyte morphological responses, including filopodia, lamellipodia, and stress fiber formation, and stellation were imaged using atomic force microscopy and phalloidin staining for F-actin. Activation of the corresponding Rho GTPase regulators was investigated using immunolabeling with Cdc42, Rac1, and RhoA. Astrocytes cultured on the nanofibrillar scaffolds showed a unique response that included stellation, cell–cell interactions by stellate processes, and evidence of depression of RhoA. The results support the hypothesis that the extracellular environment can trigger preferential activation of members of the Rho GTPase family, with demonstrable morphological consequences for cerebral cortical astrocytes.

Keywords: stellation, nanofiber, RhoA, atomic force microscopy

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