Figure 17A. Microglial cell-matrix interaction in 3D culture.

Representative confocal time-lapse images of 3D matrix fibers (silver) and Cx3cr1-GFP microglia (green). To explore possible microglial cell-matrix interactions in our 3D culture, we utilized a combination of fluorescent and confocal reflection microscopy techniques to visualize the interaction between microglia and the ECM. Time-lapse confocal z-stack images of eGFP microglia with z-slice of 0.5 um over 10 minutes with a time frame of 30 s were obtained. Confocal reflection microscopic grayscale images of the 3D gel matrix structure were simultaneously imaged using a 633 nm laser. We observed interactions between microglial cell branching processes and 3D matrix fibers (Figure 17A). Microglia constantly extended their branching processes to make several contacts with matrix fibers in 3D culture (Figure 17A). This illustrates a bidirectional cell-matrix fiber interaction; potentially promoting the more branched and ramified morphology of microglia seen in our 3D cell culture system.