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. 2016 May 31;71(12):1145–1153. doi: 10.1136/thoraxjnl-2015-207402

Figure 4.

Figure 4

Hypoxia upregulates matrix metalloproteinase-1 (MMP-1) in human respiratory epithelial cells. (A) Hypoxia increases MMP-1 secretion from normal human bronchial epithelial (NHBE) cells stimulated with control medium or conditioned media from Mtb-infected monocytes (CoMTb) incubated in 21%, 5% or 1% oxygen. (B) Dimethyloxalyl glycine (DMOG) (range 0.1–0.25 mM) drives dose-dependent MMP-1 secretion from CoMTb-stimulated NHBE cells. (C) In silico analysis of the MMP-1 promoter reveals putative hypoxic response element (HRE)-binding sites as well as consensus NF-κB-binding and AP-1-binding sites. (D) Relative luminescence following transfection of A549 respiratory epithelial cells with either WT-MMP-1 promoter or a series of MMP-1 promoter deletion constructs in normoxia (solid bars) or hypoxia (shaded bars). The effect of hypoxia in increasing promoter activity is absent in constructs −1551, −1194 and −517. (E) IKK-β inhibition in hypoxia with SC-514 in CoMTb-stimulated cells resulted in a dose-dependent decrease in MMP-1 secretion. (F) Site-directed mutagenesis of the NF-κB-binding site at −2878 to −2886 bp decreases MMP-1 promoter activity in response to CoMTb in normoxia (solid bars) or hypoxia (shaded bars). **p<0.01, *p<0.05. AP-1, activated protein-1; IKK-β, inhibitor of nuclear factor kappa-B kinase subunit beta; WT, wild type.