Cyclic tensile loading regulates human mesenchymal stem cell differentiation into neuron-like phenotype.
Mechanical loading has been utilized as an effective tool to direct mesenchymal stem cells (MSCs) commitment into cell lineages of mesodermal origin. However, the use of this tool to induce transdifferentiation of MSCs into the neural lineage has never been attempted. In this study, we examined the potential of uniaxial cyclic tensile loading in promoting neuronal differentiation of human MSCs (hMSCs) on modified biodegradable poly(ε-caprolactone) (PCL). The stem cell morphology, tissue-specific gene and protein expression, microfilament structure and, subsequently, Rho GTPase activity were analysed after cyclically stretching the cells at a range of amplitudes (0.5%, 2% or 3.5%) and frequencies (0.5, 1 or 1.5 Hz) for 8 h. hMSCs responded to these stimuli and displayed distinctly different microfilament organization. However, only those stretched at 0.5% strain amplitude and 0.5 Hz frequency showed promoted outgrowth of filopodia with significant upregulation of neurogenic genes expression. Positive staining of the neurogenic protein markers Nestin and Tuj1 suggested that the hMSCs had been committed to early neuronal progenitors. In addition, Rac1 but not RhoA was activated at this particular loading parameter. Furthermore, inhibition of Rac1 activity with NSC23766 disrupted the effect of cyclic loading. The results suggest that cyclic tensile loading at low amplitude and frequency is capable of triggering neuron-like differentiation through the regulation of Rho GTPases activity, even in the absence of neurogenic induction medium.
Division of Materials Technology, School of Materials Science and Engineering, Nanyang Technological University, Singapore; Republic Polytechnic, Singapore.
Wen Shing
WS
Leong
Shu Cheng
SC
Wu
Mintu
M
Pal
Chor Yong
CY
Tay
Haiyang
H
Yu
Huaqiong
H
Li
Lay Poh
LP
Tan
D001483:Base Sequence; D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation; D003599:Cytoskeleton / Q000378:metabolism; D017931:DNA Primers; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D013718:Tensile Strength; D020830:rac1 GTP-Binding Protein / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
D015415:Biomarkers; D017931:DNA Primers; D020830:rac1 GTP-Binding Protein; D020742:rhoA GTP-Binding Protein