Figure 6: MT1-MMP knockdown reduces matrix degradation and punctate localization of MMP9 in osteoclasts. (a) Confocal microscopy analysis of distribution of MT1-MMP and MMP9 in osteoclasts cultured on glass cover slips. Immunostaining was done in nonpermeablized osteoclasts with Triton-X100. Punctate colocalization (yellow) of MT1-MMP (green) and MMP9 (red) was observed on the cell surface. (b) and (c) Confocal microscopy analysis of osteoclasts immunostained with a MMP9 antibody (red) and degradation of gelatin matrix (green). Osteoclasts transfected with scrambled RNAi (b) and SiRNA (c) sequences to MT1-MMP were subjected to gelatin degradation for 6 h. Distribution of MMP9 (red) in nonpermeablized osteoclasts and FITC-gelatin matrix (green) is shown in the overlay panels ((b) and (c)). The results represent one of three experiments performed. Scale bar: 100 μm. Matrix degraded areas are indicated by asterisks in (b) and (c) (gelatin panel).