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

Figure 6.

Figure 6

Hypoxia-inducible factor (HIF)-1α is necessary for matrix metalloproteinase-1 (MMP-1) gene expression and secretion during Mycobacterium tuberculosis (M.tb) infection. (A) HIF-1α western blot at 24 h demonstrates suppression of HIF-1α protein by HIF-1α siRNA in monocyte-derived macrophages (MDMs) in both normoxia and hypoxia, with no knockdown observed with non-targeting (NT) siRNA. (B) HIF-1α siRNA decreases MMP-1 gene expression at 24 h in M.tb-infected MDMs incubated in hypoxia. (C) HIF-1α siRNA causes a significant decrease in MMP-1 secretion at 48 h under conditions of normoxia (solid bars) and hypoxia (hatched bars). No significant change in MMP-1 gene expression or secretion is seen with NT siRNA. (D) Lung biopsies from patients with pulmonary TB (i, ii) are immunoreactive for HIF-1α compared with uninfected control biopsies (iii). HIF-1α staining is pronounced within macrophages and multinucleated giant cells (arrow, ii). Scale bars, 100 µm. ****p<0.0001, *p<0.05. siRNA, small interfering RNA.