The differentiation of Lgr5+ progenitor cells on nanostructures of self-assembled silica beads.

Supporting cells(SCs) have been demonstrated to be a reliable source for regenerating hair cells(HCs). Previous research has reported that Lgr5+ SCs can regenerate HCs both in vitro and in vivo. However, there is limited knowledge about the impact of the material on Lgr5+ cells. In this study, Lgr5+ cells were isolated from neonatal Lgr5-EGFP-CreERT2 transgenic mice by flow cytometry and then plated on self-assembled silica beads (SB). Lgr5+ cell differentiation was observed by immunofluorescence. We found that in the direct differentiation assay, the SB group generated more hair cells than the control group(*p < 0.05). Especially in the SB group, Lgr5+ progenitors generated significantly more Myo7a+ HCs outside of the colony than in the control group(**p < 0.01). In the sphere differentiation assay, we found that the diameter of spheres in the SB group was significantly larger compared to those of the control group(**p < 0.01). However, the difference in the ratio of myo7a+ cell counts was not obvious(P>0.05). The experiment proved that the self-assembled silica beads could promote the differentiation of Lgr5+ progenitors in vitro. Our findings implicate that nanostructures of self-assembled silica beads can be used as vectors for stem cell research in the inner ear.