Microglia near neurons in co-cultures engulf neuronal materials.

<p><b>A.</b> Hippocampal neurons 19 DIV were coincubated with microglia for 2 days, immunostained with CD11b (green), a marker of microglia, and GluA1 (red), and visualized with Alexa Fluor488 or 555-conjugated secondary antibodies. Scale bar, 20 µm. <b>B.</b> Images showing microglia (phalloidin, red) and neurons (obtained from β-actin-EGFP mice, green) in co-cultures. Arrows point to neuronal material within the microglia. Scale bars, 20 µm (left); 5 µm (right). <b>C.</b> Images showing Mac-2⁺ microglia (green), the lysosomal marker LAMP-1 (red), and presynaptic puncta immunostained for synapsin I (white) in co-culture. Scale bars, 20 m. <b>D.</b> Orthogonal views of the engulfed presynaptic material (white arrowheads in <b>C</b>).