(A) study on the phenotype retention of mechanically induced differentiation on human neural stem cells

Abstract

Neural stem cell (NSC) therapy has drawn a great attention in the regenerative medicine due to their therapeutic potential for neurodegenerative diseases. Previous studies have focused on modulating neuronal differentiation of NSCs to control NSCs fate decision via biophysical stimulation from nanotopography. Recently, it has been found that stem cells can remember their past physical cues and these can be harnessed to dose cells with physical cues. However, conventional approaches s to modulate differentiation of NSCs with nanotopographic patterns could not access the effect of mechanical dosing and mechanical memory on NSCs due to their technical limitations. In our study, we developed a dynamically tunable nanowrinkle platform to investigate the effect of mechanical doing and mechanical memory on the differentiation of human neural stem cells (hNSCs). First, nanowrinkle patterns effectively enhance differentiation of hNSCs compared to flat substrates. Because of nanowrinkle effects on the morphology of hNSCs, the length of the neurite of hNSCs on nanowrinkle patterns was significantly elongated and aligned to each other, which indicates enhanced neurogenesis of hNSCs. In addition, we found that neuronal gene expression levels (TUJ1, MAP2, and Nestin) were increased in hNSCs mechanically dosed more than 5 days and they retained their morphology even when nanowrinkle patterns were disappeared. We conclude that neural stem cells possess mechanical memory with their morphology and neuronal gene expression levels that hNSCs store information about their past physical cues influencing overall hNSCs fate.