Surface curvature promotes coordinated extracellular matrix remodeling and mechanotransductive signaling during osteoblast adaptation

Background: Substrate curvature is an important biophysical cue regulating cell behavior through mechanotransduction. However, how three-dimensional curvature regulates osteoblast transcriptional adaptation remains poorly understood. We investigated the temporal transcriptional response of pre-osteoblastic cells to defined substrate curvature. Methods: Murine MC3T3-E1 pre-osteoblasts were cultured on three-dimensional polydimethylsiloxane capillary bridges or flat substrates for 7 and 23 days to investigate the effects of surface curvature on gene expression. A genome-wide transcriptomic approach was employed to comprehensively characterize differential gene expression, followed by a focused analysis of selected biological pathways, including osteogenic signaling, extracellular matrix (ECM) organization, cell-matrix adhesion, cytoskeletal regulation, and mechanosensitive signaling. Results: Substrate curvature induced pronounced, time-dependent transcriptional changes. At day 7, curved substrates activated immediate-early and stress-responsive genes, including Egr1, Egr2, Fos, Junb, and Nr4a1. By day 23, the response shifted toward ECM remodeling, receptor-mediated signaling, and structural adaptation, including increased expression of Ankrd1, Ereg, Serpine1, and Plaur. Despite these changes, canonical osteogenic transcription factors, including Runx2, Cbfb, Osx/Sp7, and Atf4, showed limited alterations. In contrast, BMP, WNT, FGF, and Notch signaling, ECM components, integrins, and actin-associated genes were dynamically regulated, whereas Piezo1, Piezo2, and most septins remained comparatively stable. Conclusions: Substrate curvature regulates osteoblast transcriptional adaptation primarily through coordinated changes in ECM organization, cell-matrix interactions, cytoskeletal architecture, and signaling networks rather than reprogramming the canonical osteogenic transcriptional machinery.