Fig. 2: Inputs engulfed by OPCs are degraded within phagosomal compartments.
From: Oligodendrocyte precursor cells engulf synapses during circuit remodeling in mice
a, Confocal images and reconstructions of an OPC (tdTomato, pseudocolored green), LRP1 (cyan) and TC inputs (VGluT2). VGluT2 inputs with LRP1 in magenta, without LRP1 in white. Scale bars, 5 µm, 1 µm (inset) and 5 µm (fluorescence). b, Images and reconstruction of an OPC (tdTomato, green) containing the early phagosomal marker EEA1 (cyan) and TC inputs (VGluT2, magenta). Yellow arrowheads, colocalization between VGluT2 and EEA1. Scale bars, 2 µm, 1 µm (inset) and 4 µm (fluorescence). c, Reconstruction of an OPC (tdTomato, green) containing the late phagosomal marker Rab7 (cyan) and TC inputs (VGluT2, magenta). Yellow arrowheads, colocalization between VGluT2 and Rab7. Scale bars, 2 µm, 0.5 µm (inset) and 2 µm (fluorescence). d, Images and reconstruction of an OPC (tdTomato, green) containing TC inputs (VGluT2, magenta) and lysosomes (Lamp2, blue). White arrowheads, colocalization between VGluT2 and Lamp2. Scale bars, 2 µm, 1 µm (inset) and 2 µm (fluorescence). e, Images of an OPC (tdTomato, green), TC inputs (AAV-hSYN-eGFP, magenta) and Lamp2 (blue) taken on a structured illumination microscope alongside reconstructions. Scale bars, 16 μm, 1 μm (inset). (i), Increased magnification of inputs outside of Lamp2. Scale bar, 1 μm. (ii,iii), Orthogonal views of the OPC (green) containing inputs (white). Scale bar, 1 μm. f, Images and reconstructions of an OPC (NG2, green) containing TC inputs expressing AAV-hSYN-pSynDig (magenta and white) and an image of the pSynDig-expressing inputs within the volume of the OPC. Scale bars, 10 μm and 1 µm (inset). g, Quantification of pSynDig eGFP and mCherry signals within OPCs. Two-tailed ratio paired t-test, P = 0.0485; n = 25 cells from three mice. h, Images and reconstruction of an OPC (yellow) and pSynDig fluorescence signal (intact inputs, white; inputs being digested, magenta) taken on an Airyscan microscope. Lines demonstrate the location along the reconstructed OPC from which the cross-section image on the right was taken. In panels on the right, the OPC volume is outlined in yellow. Scale bars, 2 μm and 1 μm (cross-sections). *P < 0.05.
