Eun Hyun Ahna, b, 1, Younghoon Kimi, 1, Kshitizc, d, 1, Steven S. Ane, f, g, Junaid Afzalh, Suengwon Leee, Moonkyu Kwakj, 2, Kahp-Yang Suhj, Deok-Ho Kimb, c, Andre Levchenkod
a Department of Pathology, University of Washington, Seattle, WA, USA
b Institute of Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
c Department of Bioengineering, University of Washington, Seattle, WA, USA
d Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
e Department of Environmental Health Sciences, Johns Hopkins University, Baltimore, MD, USA
f Physical Sciences in Oncology Center, Johns Hopkins University, Baltimore, MD, USA
g In Vivo Cellular and Molecular Imaging Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
h Department of Medicine, The Johns Hopkins Medical Institutions, Baltimore, MD, USA
i Department of Chemical Engineering, Johns Hopkins University, Baltimore, MD, USA
j Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul, Republic of Korea
1 Equal contribution.
2 Present address: School of Mechanical Engineering, Kyungpook National University, Daegu, Republic of Korea.
Adult stem cells hold great promise as a source of diverse terminally differentiated cell types for tissue engineering applications. However, due to the complexity of chemical and mechanical cues specifying differentiation outcomes, development of arbitrarily complex geometric and structural arrangements of cells, adopting multiple fates from the same initial stem cell population, has been difficult. Here, we show that the topography of the cell adhesion substratum can be an instructive cue to adult stem cells and topographical variations can strongly bias the differentiation outcome of the cells towards adipocyte or osteocyte fates. Switches in cell fate decision from adipogenic to osteogenic lineages were accompanied by changes in cytoskeletal stiffness, spanning a considerable range in the cell softness/rigidity spectrum. Our findings suggest that human mesenchymal stem cells (hMSC) can respond to the varying density of nanotopographical cues by regulating their internal cytoskeletal network and use these mechanical changes to guide them toward making cell fate decisions. We used this finding to design a complex two-dimensional pattern of co-localized cells preferentially adopting two alternative fates, thus paving the road for designing and building more complex tissue constructs with diverse biomedical applications.
Keywords : Human mesenchymal stem cells; Differentiation; Nanotopography; Osteogenesis; Adipogenesis; Capillary force lithography