Actomyosin contractility plays a role in MAP2 expression during nanotopography-directed neuronal differentiation of human embry

23 février 2015

Biomaterials. 2015 Apr;47:20-8. doi: 10.1016/j.biomaterials.2015.01.003. Epub 2015 Feb 2.

Actomyosin contractility plays a role in MAP2 expression during nanotopography-directed

neuronal differentiation of human embryonic stem cells.

Ankam S1, Lim CK2, Yim EK3.

Author information

1Department of Biomedical Engineering, National University of Singapore, 9 Engineering Drive 1, EA 03-12, Singapore 117576, Singapore.
2Mechanobiology Institute, National University of Singapore, T-lab, #05-01, 5A Engineering Drive 1, Singapore 117411, Singapore.
3Department of Biomedical Engineering, National University of Singapore, 9 Engineering Drive 1, EA 03-12, Singapore 117576, Singapore; Mechanobiology Institute, National University of Singapore, T-lab, #05-01, 5A Engineering Drive 1, Singapore 117411, Singapore; Department of Surgery, National University of Singapore, NUHS Tower Block, Level 8, 1E Kent Ridge Road, Singapore 119228, Singapore. Electronic address: eyim@nus.edu.sg.

Abstract:

Pluripotent human embryonic stem cells (hESCs) have the capability of differentiating into different lineages based on specific environmental cues. We had previously shown that hESCs can be primed to differentiate into either neurons or glial cells, depending on the arrangement, geometry and size of their substrate topography. In particular, anisotropically patterned substrates like gratings were found to favour the differentiation of hESCs into neurons rather than glial cells. In this study, our aim is to elucidate the underlying mechanisms of topography-induced differentiation of hESCs towards neuronal lineages. We show that high actomyosin contractility induced by a nano-grating topography is crucial for neuronal maturation. Treatment of cells with the myosin II inhibitor (blebbistatin) and myosin light chain kinase inhibitor (ML-7) greatly reduces the expression level of microtubule-associated protein 2 (MAP2). On the other hand, our qPCR array results showed that PAX5, BRN3A and NEUROD1 were highly expressed in hESCs grown on nano-grating substrates as compared to unpatterned substrates, suggesting the possible involvement of these genes in topography-mediated neuronal differentiation of hESCs. Interestingly, YAP was localized to the cytoplasm of differentiating hESCs. Taken together, our study has provided new insights in understanding the mechanotransduction of topographical cues during neuronal differentiation of hESCs.

KEYWORDS:

Cytoskeletal contractility; Focal adhesion; Mechanobiology; Nanotopography; Neuronal maturation; Pluripotent stem cells