Hypoxia Associated Proteolytic Processing of OS-9 by the Metalloproteinase Meprin β

Figure 8

Immunofluorescence staining for HIF-1α (red) and OS-9 (green) in MDCK cells following exposure to CoCl₂. Mock transfected control (a) and meprin β transfected MDCK cells (b) were cultured in chamber slides to 80–90% confluence. The cells were serum-starved overnight, exposed to 125 μM CoCl₂ and fixed in 1% paraformaldehyde. Anti-HIF-1α and anti-OS-9 antibodies were used to evaluate localization of HIF-1α and OS-9 in the cells by confocal microscopy. There was a time-dependent increase in nuclear levels of HIF-1α in both genotypes of cells, confirming stabilization of HIF-1α in the nucleus. The cytosolic levels OS-9 increased in a time-dependent manner in the nontransfected MDCK cells following exposure to CoCl₂ (a). This increase was not as dramatic in meprin β transfected MDCK cells (b).

(a)

(b)