Ex vivo pretreatment of MSCs

MSCs were treated with various hypoxia-mimicking chemicals. An incubation time of 24 h was selected on the basis of previous studies showing that expression of CXCR4 increased in a time-dependent manner after treatment with VPA (1.0 mM), CoCl₂ (100 μM) and DFX (120 μM) [^42,43]. After incubation, MSCs were extensively washed with 1x PBS, dissociated from T75 cell culture flasks with Accutase (Sigma-Aldrich) for 5 min at 37°C, centrifuged (at 400 g for 6 min) and resuspended in DMEM prior to in vitro migration assay.