RNA-seq reveals correlations between cytoskeleton-related genes and the osteogenic activity of mesenchymal stem cells on strontium loaded titania nanotube arrays

Strontium loaded titania nanotube arrays (NTSr), as well as titania nanotube arrays (NT), have been regarded as effective coatings to promote bone regeneration on titanium implants, but an understanding of the full extent of early processes affected by such surface modifications is absent. To address this limitation, we performed RNA sequencing (RNA-seq) of Sprague-Dawley rat bone marrow mesenchymal stem cells (rBMMSCs) cultured on unmodified titanium sheets (Con), NT and NTSr specimens. By pairwise comparisons we found that NT and NTSr shared a majority of differentially expressed genes. The Gene Ontology (GO) analysis revealed that NT and NTSr up-regulated a bunch of genes that are annotated to the cytoskeleton. The results were supported by immunofluorescent, transmission electron microscopy (TEM) and western blotting assays. By inhibiting the cytoskeleton through pharmacological agents, the activities of alkaline phosphatase (ALP) on NT and NTSr were also suppressed. Informed by these results, we concluded that NT and NTSr specimens reorganized the cytoskeleton of cultured cells that may play a crucial role in osteogenic lineage commitment. This work uncovered the transcriptome-wide responses of Sprague-Dawley rat bone marrow mesenchymal stem cells on unmodified titanium sheets (Con), TiO2 nanotube array (NT) and strontium loaded TiO2 nanotube array (NTSr) coated titanium sheets. Through a high-throughput sequencing technique and further validation assays we found that genes that are annotated with the cytoskeleton or the cytoskeleton-associated processes were up-regulated on NT and NTSr samples, and these alterations may play a crucial role in topography-induced osteogenic lineage commitment of stem cells on these surfaces. [Display omitted] •The transcriptome-wide differences were unveiled by employing RNA-seq on Con, NT and NTSr specimens.•A strengthened cytoskeleton organization of MSCs on NT and NTSr specimens was found.•The enhanced cytoskeleton-related profiles played a crucial role in osteogenic lineage commitment of MSCs.