EMF-induced mesenchymal stem cell migration is mediated by SOCE-dependent calcium influx and modulated by ROCK signaling

Electromagnetic field (EMF) exposure promotes mesenchymal stem cell (MSCs) migration, a critical process in regenerative medicine. While calcium (Ca²⁺) signaling is implicated, the primary Ca²⁺ entry pathway and its downstream mechanisms remain elusive. This study investigates the hypothesis that store-operated calcium entry (SOCE) serves as a major Ca²⁺ influx mechanism and modulates the ROCK pathway to drive EMF-induced MSCs migration. Rat bone marrow-derived MSCs were exposed to a 50 Hz, 5 mT sinusoidal EMF. Cell migration was assessed via Transwell assays. Intracellular Ca²⁺ and SOCE activity were measured using Fluo-4 AM. Transcriptomic profiling was performed by RNA Sequencing. Cytoskeletal reorganization (F-actin, acetylated α-tubulin) and protein expression (Orai1, ROCK1/2) were analyzed by immunofluorescence and western blotting, using pharmacological inhibitors (BTP2 for SOCE, Y-27632 for ROCK) and calcium chelators to dissect the pathway. EMF exposure significantly enhanced MSCs migration and activated calcium signaling pathways. This pro-migratory effect was strictly dependent on extracellular Ca²⁺ influx and was abolished by SOCE inhibition with BTP2. EMF upregulated the SOCE channel Orai1 and enhanced SOCE activity. Crucially, EMF suppressed ROCK1/2 expression under normal conditions, but this suppression was not reversed under SOCE inhibition or in low-calcium medium and EMF exposure increased ROCK1/2 expression in Ca²⁺-free medium (with 2 mM EGTA). SOCE inhibition also attenuated EMF-induced cytoskeletal reorganization, including perinuclear accumulation of acetylated α-tubulin and F-actin polymerization. Our findings establish SOCE-mediated Ca²⁺ influx as the critical driver of EMF-promoted MSCs migration. This process involves the upregulation of Orai1 and elicits a biphasic, context-dependent modulation of the ROCK pathway. The pro-migratory phenotype requires the synergy of SOCE-dependent Ca²⁺ influx and ROCK downregulation, leading to coordinated cytoskeletal remodeling. This study redefines the mechanistic understanding of EMF bioeffects, highlighting SOCE as a key regulator that integrates calcium signaling with cytoskeletal dynamics to control cell migration.