Global metabolomics identifies new extracellular biomarkers of nanovibration-driven mesenchymal stem cells osteodifferentiation

Bone-related conditions are a leading cause of disability and rising healthcare costs, prompting interest in tissue engineering solutions using mesenchymal stem cells (MSC). As part of an effort to eliminate synthetic osteogenic compounds, this study characterizes the metabolic adaptations of MSC to chemical-free nanovibration (or nanokicking, NK)-induced osteodifferentiation. Through articulation of conventional gene/protein/functional markers and a global metabolomics/lipidomics strategy, our findings indicate successful slow-paced osteodifferentiation, expressed by subtle and partially reversible intracellular changes, and pronounced, largely irreversible, extracellular alterations. The initial 7 days post-stimulation are accompanied by high energy demands and phosphocholine hydrolysis, both effects attenuated thereafter. In contrast, early membrane remodeling persists until day 21, possibly to facilitate increased membrane fluidity, vesicle formation and activated signaling cascades. Also after day 7, increased antioxidant activity, redox regulation, and glycerolipid redirection towards phospholipid biosynthesis are evident. Concurrent sphingolipid modulation may support the synthesis of bioactive lipids, phosphate production for mineralization and lipid raft assembly. NK was reinforced as a more targeted osteocommitment induction strategy, compared to traditional protocols, with cellular metabolic adaptations likely to involve upregulation of several kinases (e.g., ERK1/2, Akt, p70S6K, creatine kinase), glutathione peroxidase and lipophagy. This global metabolomics approach unveiled the overall metabolic features of NK-induced osteodifferentiation of human adipose tissue MSC and highlighted the potential of extracellular metabolite signatures to monitor differentiation dynamics in real-time and gain deeper insight into nano-bio interactions.