DNase-active podosomes respond to pathogens and immunogenic material. (a) A migrating macrophage-like cell (THP-1) formed dense podosomes in the leading edge and degraded the surface DNA along the path (Video 4). (b) A macrophage-like cell (THP-1) specifically reacted to surface-immobilized E. coli (dark short rod-like objects) with DNase activity (Video 5). (c) DNase-active podosomes formed around surface-immobilized E. coli in a rosette pattern (yellow arrows), degrading the local extracellular DNA (SNS), until E. coli was internalized. (d) Coimaging of SNS signal and F-actin of a THP-1 cell around a bacterium. (e) THP-1 cells formed podosome rosettes around the antigen (donkey IgG) islands (size, 5 µm) and degraded the surrounding surface DNA, showing general reaction to the immunogenic material by forming DNase-active podosomes. Note that SNS was not coated on the IgG islands but was coated in the background. (f) DNase-active podosomes degrade bacterial DNA. THP-1 cells on a surface uniformly coated with bacterial DNA extracted from E. coli. DNA was stained with Sytox green. (g) A THP-1 cell on a surface decorated with chromosomal DNA spilled by individual E. coli lysed on site. Arrows indicate the DNA degrading sites. DNA was stained with Sytox green.