Fig. 1

ABCB5⁺ MSCs alleviate overloading of Cyto Ca²⁺ in hypoxic HUVECs. A–D HUVECs loaded with 2 μM Fura-2-acetoxymethyl ester (Fura 2-AM, Biotium, USA, 50033) were treated with A 80 μM CoCl₂; B 120 μM DFO; C 3 μM TG; D 100 μM H₂O₂ in HHBSS buffer without Ca²⁺ for 2 h. After 2 h, buffer was changed to HHBSS (contains DFO, CoCl₂ or TG) with Ca²⁺. 100 μM Ionomycin (Ion) was used as positive control. The ratio of the fluorescence-emission intensities at 535 nm (340/380 nm) was measured using a Tecan multimode microplate reader by alternating excitation wavelength between 340 and 380 nm. E–G HUVECs loaded with 2 μM Fura 2-AM were treated with 80 μM CoCl₂, or 120 μM DFO or 3 μM TG and the 100 μM Ion in medium for 4 h. Afterward, HUEVCs were either co-cultured with ABCB5⁺MSCs (CoCl₂-CO; DFO-CO; TG-CO) or cultured in ABCB5⁺ MSC-CM (CoCl₂-CM; DFO-CM, TG-CM) for 24 h. Changes in Fura-2 ratio in HUVECs under E CoCl₂, CoCl₂-CM and CoCl₂-CO treatments; F DFO, DFO-CM and DFO-CO treatments; G TG, TG-CM and TG-CO treatments. H Changes in Fura-2 ratio in HUVECs treated by 100 μM Ion and 100 μM H₂O₂. Data is represented as mean ± SD, n = 3 in each group, ns, not significant, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001