Hypoxia Inducible Factor-1α Regulates the Migration of Bone Marrow Mesenchymal Stem Cells via Integrin α₄

Figure 1

HIF-1α induction by exposure to hypoxia stimulates BM-MSC migration. (a) Real-time PCR analysis showing the transcription levels of HIF-1α in BM-MSCs under normoxic or hypoxic conditions. 18S rRNA was used as the loading control. (b) Protein expression levels of HIF-1α in BM-MSCs under normoxic or hypoxic conditions were analyzed by Western blotting. GAPDH was used as the loading control. (c) Protein expression levels of HIF-1α in BM-MSCs under normoxic or hypoxic conditions after pretreatment with YC-1, an inhibitor of HIF-1α, were analyzed by Western blotting. (d) Immunofluorescence staining showing localization of HIF-1α in BM-MSCs after YC-1 pretreatment under normoxic or hypoxic conditions. Blue: DAPI; green: HIF-1α. Scale bar = 80 μm (400x original magnification). (e) Invasiveness of BM-MSCs after pretreatment with YC-1 determined by invasion assay (left). Quantification of the cells invaded through the inserts (right). (f) Enzymatic activities of MMP-9 and MMP-2 in BM-MSCs under the indicated conditions analyzed by zymography (left). Quantification of enzymatic activities of MMP-9 (middle) and MMP-2 (right). (compared with YC-1 nontreated group) and (compared with normoxic group). DAPI: 4′,6-diamidino-2-phenylindole; HIF-1α: hypoxia-inducible factor-1α; MMP: matrix metalloproteinase.

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