Mechanical Force Induces Osteogenic Differentiation of Murine Induced Pluripotent Stem Cells via TGF-β Signalling

Abstract

Objectives: Mechanical forces are pivotal in regulating various cellular responses, particularly in periodontal ligament and bone. However, the effects of mechanical force are contingent upon several factors, including force types, duration, magnitude and the differentiation stage of the cells. The present study investigated the impact of intermittent compressive force (ICF) on osteogenic differentiation in murine gingiva-derived induced pluripotent stem cells (miPS). Materials and Methods: Adherent retinoic acid-treated miPS were subjected to ICF in a serum-free medium for 24 h. Real-time polymerase chain reaction, western blot analysis and immunofluorescence staining were employed to evaluate mRNA and protein expression patterns. In vitro mineralisation was assessed using alizarin red S staining. Results: Our findings revealed that ICF treatment induced the expression of osteogenic markers, including Runx2, Col1a1, Opn and Dlx5. Furthermore, ICF promoted the release of extracellular adenosine triphosphate (ATP) at 24 h. Pretreatment with ICF increased in vitro mineralisation, while ATP priming did not enhance mineralisation in adherent retinoic acid-treated miPS. A TGF-β inhibitor attenuated the ICF-upregulated Runx2, Col1a1, Opn and Dlx5 as well as the ICF-induced in vitro mineralisation. Conclusion: Collectively, our results suggest that ICF can induce osteogenic differentiation of adherent retinoic acid-treated miPS, mediated through TGF-β signalling. Eventually, such information could be of value in controlling iPS responses during regenerative treatment applications.