Nanovibrational stimulation inhibits osteoclastogenesis and enhances osteogenesis in co-cultures

John W Kennedy,Peter S Young,P Monica Tsimbouri,Paul Campsie,Matthew J Dalby,Peter G Childs,Carl S Goodyear,Shatakshi Sood,Dominic R M Meek,Stuart Reid

doi:10.1038/s41598-021-02139-9

Abstract

Models of bone remodelling could be useful in drug discovery, particularly if the model is one that replicates bone regeneration with reduction in osteoclast activity. Here we use nanovibrational stimulation to achieve this in a 3D co-culture of primary human osteoprogenitor and osteoclast progenitor cells. We show that 1000 Hz frequency, 40 nm amplitude vibration reduces osteoclast formation and activity in human mononuclear CD14+ blood cells. Additionally, this nanoscale vibration both enhances osteogenesis and reduces osteoclastogenesis in a co-culture of primary human bone marrow stromal cells and bone marrow hematopoietic cells. Further, we use metabolomics to identify Akt (protein kinase C) as a potential mediator. Akt is known to be involved in bone differentiation via transforming growth factor beta 1 (TGFβ1) and bone morphogenetic protein 2 (BMP2) and it has been implicated in reduced osteoclast activity via Guanine nucleotide-binding protein subunit α13 (Gα13). With further validation, our nanovibrational bioreactor could be used to help provide humanised 3D models for drug screening.

Highlights

Models of bone remodelling could be useful in drug discovery, if the model is one that replicates bone regeneration with reduction in osteoclast activity
This is because osteoblastic cells signal to macrophages to fuse and form osteoclasts via receptor activator of nuclear factor κB ligand (RANKL) and macrophage-colony stimulating factor (M-CSF), or prevent fusion by expression of the RANKL decoy receptor osteoprotegrin (OPG), providing homeostatic c ontrol[8]
We have previously reported a simple co-culture system comprising of primary bone marrow stromal cells (BMSCs) and bone marrow hematopoietic cells (BMHCs) where osteogenic and osteoclastic development can be observed and their interactions s tudied[17,18]

Summary

Discussion

We report on a mechanical bioreactor that provides nanoscale stimulation to osteoblastic cells while reducing osteoclast formation in appropriate co-culture conditions. As well as stimulating osteogenesis of BMSCs, we demonstrate, for the first time, reduction of osteoclast formation and activity in 2D and 3D co-cultures This is important as the interplay between osteoblasts and osteoclasts is crucial to normal bone development, homeostasis and remodelling after injury. Our approach allows us to understand that both bone formation and osteoclast fusion and activity are effected at the intermediate, 1000 Hz, frequency This allows us to envisage a direct application of nanovibration, as with whole body vibration[56] and low-intensity pulsed u ltrasound[57], after further in vivo evaluation using technologies similar to bone conduction headphones (1000 Hz is an audible signal)[58].

Conclusion

Findings

Materials and methods