Piezo1 mediated mechanotransduction modulates macrophages proliferation during bone remodeling via PI3K-AKT-Ccnd1 axis

Macrophages play a pivotal role in mechanical force-induced inflammatory bone remodeling. Yet, how macrophages perceive mechanical stimuli and thereby modulate biological behaviors remain elusive. The orthodontic tooth movement (OTM) model was established to access the role of Piezo1 in modulating macrophage response upon mechanical stimuli. The potential functions and molecule mechanisms of Piezo1 were explored by bone marrow-derived macrophages (BMDMs) using mechanical stretch system, western blotting, immunofluorescence, flow cytometry and RNA sequencing. We first found macrophage proliferative phenotype enhanced at the later stage of force application. The biological variation mediated by mechanical force could be suppressed by Piezo1 inhibition. Furthermore, Piezo1 activated PI3K-AKT signaling was closely associated with macrophage proliferation upon mechanical stimuli. Additionally, Ccnd1 was authenticated as a critical downstream factor of PI3K-AKT signaling and conditional ablation of Ccnd1 in macrophages inhibited macrophage proliferation in mechanical force-induced bone remodeling procedure. To probe the mechanisms by which Piezo1 promotes macrophage proliferation upon mechanical stimuli, RNA-seq experiments was conducted on BMDMs transfected with si-NC and si-Piezo1 and exposed to mechanical stretch