Brushite-modified titanium surface elicits early osteointegrative gene expression signatures in human mesenchymal stem cells: insights from NGS analysis

Abstract

Brushite (dicalcium phosphate dihydrate) is a resorbable coating with significant potential to enhance implant osseointegration. However, the early molecular mechanisms through which it directs mesenchymal stem cell (MSC) behavior remain poorly understood. This study investigates the early transcriptional response of human MSCs cultured on brushite-coated Ti6Al4V compared to uncoated titanium at 7 days, a critical regulatory window that precedes overt differentiation. By employing both basal and osteogenic culture conditions, we decoupled material-specific effects from soluble biochemical cues. ICP-OES confirmed a high-purity Ca/P-based coating. RNA-seq analysis identified 390 and 613 differentially expressed genes under osteogenic and basal conditions, respectively, demonstrating a robust material-driven response. Pathway enrichment revealed the selective involvement of pro-osteogenic signaling (BMP, Wnt, Hedgehog), metabolic/mitochondrial reprogramming, and a controlled inflammatory response. Conversely, the downregulation of proliferation- and mechanotransduction-related genes is consistent with a transition toward a stabilized, differentiation-permissive state. Notably, a 25-gene core signature was identified across all conditions, representing a stable material-dependent transcriptional fingerprint. These findings were validated by qRT-PCR and corroborated at the protein level via multiplex assays (Bio-Plex), showing increased secretion of extracellular matrix and pro-regenerative factors. Collectively, our findings suggest that brushite is not merely a passive scaffold but promotes an early transcriptional program in MSCs consistent with osteogenic commitment, highlighting its potential to accelerate the clinical performance of bioactive implants.