Differential Regulation of Human Bone Marrow Mesenchymal Stromal Cell Chondrogenesis by Hypoxia Inducible Factor-1α Hydroxylase Inhibitors.
The transcriptional profile induced by hypoxia plays important roles in the chondrogenic differentiation of marrow stromal/stem cells (MSC) and is mediated by the hypoxia inducible factor (HIF) complex. However, various compounds can also stabilize HIF's oxygen-responsive element, HIF-1α, at normoxia and mimic many hypoxia-induced cellular responses. Such compounds may prove efficacious in cartilage tissue engineering, where microenvironmental cues may mediate functional tissue formation. Here, we investigated three HIF-stabilizing compounds, which each have distinct mechanisms of action, to understand how they differentially influenced the chondrogenesis of human bone marrow-derived MSC (hBM-MSC) in vitro. hBM-MSCs were chondrogenically-induced in transforming growth factor-β3-containing media in the presence of HIF-stabilizing compounds. HIF-1α stabilization was assessed by HIF-1α immunofluorescence staining, expression of HIF target and articular chondrocyte specific genes by quantitative polymerase chain reaction, and cartilage-like extracellular matrix production by immunofluorescence and histochemical staining. We demonstrate that all three compounds induced similar levels of HIF-1α nuclear localization. However, while the 2-oxoglutarate analog dimethyloxalylglycine (DMOG) promoted upregulation of a selection of HIF target genes, desferrioxamine (DFX) and cobalt chloride (CoCl2 ), compounds that chelate or compete with divalent iron (Fe2+ ), respectively, did not. Moreover, DMOG induced a more chondrogenic transcriptional profile, which was abolished by Acriflavine, an inhibitor of HIF-1α-HIF-β binding, while the chondrogenic effects of DFX and CoCl2 were more limited. Together, these data suggest that HIF-1α function during hBM-MSC chondrogenesis may be regulated by mechanisms with a greater dependence on 2-oxoglutarate than Fe2+ availability. These results may have important implications for understanding cartilage disease and developing targeted therapies for cartilage repair. Stem Cells 2018;36:1380-1392.
['Taheem|Dheraj K|DK|0000-0002-0252-6677', 'Foyt|Daniel A|DA|', 'Loaiza|Sandra|S|', 'Ferreira|Silvia A|SA|', 'Ilic|Dusko|D|', 'Auner|Holger W|HW|', 'Grigoriadis|Agamemnon E|AE|', 'Jell|Gavin|G|', 'Gentleman|Eileen|E|']
D000600:Amino Acids, Dicarboxylic D001854:Bone Marrow Cells D002454:Cell Differentiation D015687:Cell Hypoxia D002648:Child D020219:Chondrogenesis D003035:Cobalt D003676:Deferoxamine D004791:Enzyme Inhibitors D006801:Humans D051795:Hypoxia-Inducible Factor 1, alpha Subunit D064799:Hypoxia-Inducible Factor-Proline Dioxygenases D059630:Mesenchymal Stem Cells
Differentiation Chondrogenesis Hypoxia Bone marrow stromal cells (BMSCs) Cell signaling Mesenchymal stem cells (MSCs) Tissue regeneration