Abstract
Recent studies have highlighted the strong influence of microenvironmental stiffness on various cell fates including proliferation, migration, and differentiation in both two- and three-dimensional culture conditions. Our study attempts to understand the role of 3D microenvironmental stiffness on cell cytotoxic response using neural glioblastoma U-87 cells encapsulated in alginate hydrogel matrices of varying stiffness as the model system. Interestingly, we observed that cells encapsulated in soft alginate matrices were more sensitive to the toxic chemicals relative to cells encapsulated in stiffer matrices. The observed dependence of toxic responses on matrix stiffness was also seen for other neural cell lines including U-251 glioblastoma and IMR-32 neuroblastoma cells. Given the established involvement of Rho GTPases in mediating mechanosensitive cell responses, we also performed the toxicity assays using U-87 cells expressing constitutively active mutants of the Rho GTPase RhoA. Under these conditions, the toxic responses were similar for U-87 cells cultured in both soft and stiff matrices. These results suggest a strong role of mechanotransductive signaling on the response of neural cells to toxins. We believe that determining the role of substrate stiffness on the toxic response of neural cells will be crucial to the development of optimal in vitro cell-based screens of neurotoxicity.
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Acknowledgments
We thank Sanjay Kumar at University of California, Berkeley for the CA RhoA U-87 and DN RhoA U-87 cells and Joanna L. MacKay for help with the culture of the cells. We would like to thank those Bioengineering undergraduate students from the Fall 2012 Tissue Engineering class at Santa Clara University for assistance in data collection. We thank Jose Marcial Portilla for assistance in preparing the figures, Sabrina A. Cismas and Nicolo Philip Mendoza for critical reading of the manuscript and helpful suggestions. This research was supported by School of Engineering, Santa Clara University.
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Kalpith Ramamoorthi, Jared Hara, CadeEllis Ito, and Prashanth Asuri declare that they have no conflicts of interest.
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No human studies were carried out by the authors for this article. No animal studies were carried out by the authors for this article.
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Associate Editor Michael R. King oversaw the review of this article.
Jared Hara and CadeEllis Ito: These authors contributed equally to this work.
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Ramamoorthi, K., Hara, J., Ito, C. et al. Role of Three-Dimensional Matrix Stiffness in Regulating the Response of Human Neural Cells to Toxins. Cel. Mol. Bioeng. 7, 278–284 (2014). https://doi.org/10.1007/s12195-014-0326-y
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DOI: https://doi.org/10.1007/s12195-014-0326-y