Fig. 2: Spontaneous uptake of synaptic structures by OPCs.
From: Human oligodendrocyte progenitor cells mediate synapse elimination through TAM receptor activation
a Representative IHC image at 130 DIV showing microglia (IBA1) closely surveying synaptic terminals (PSD-95). b Representative IHC image at 130 DIV showing OPCs (PDGFRα) in extensive contacts with synaptic terminals (SYN1). c Representative IHC image at 130 DIV of OPCs displaying various levels of synapse internalisation, with an Imaris-based volumetric reconstruction (magnification) of an OPC engulfing post-synaptic excitatory elements (PSD-95). The statistics-based colour-code indicates the volumetric overlap of PSD-95 particles with PDGFRα+ surface (magenta = complete internalisation). Representative images (a–c) were observed in at least two independent organoid batches derived from five iPSC lines with similar results. d Imaris-based volumetric reconstruction of post-synaptic objects (GEPH) within microglia (IBA1), some localised within phagolysosomes (LAMP2). The statistics-based colour code indicates the volumetric overlap of GEPH puncta with IBA1+ surface (magenta = complete internalisation). e Imaris-based volumetric reconstruction of post-synaptic terminals (GEPH) within OPCs (PDGFRα), some localised within phagolysosomes (LAMP2). The statistics-based colour code indicates the volumetric overlap of GEPH puncta with PDGFRα+ surface (magenta = complete internalisation). f Quantification of total internalised volume of GEPH+ objects displaying ≥90% volumetric overlap with the surface of microglia or OPCs, normalised by respective cell volume. Data from 8 OPCs and 6 microglia per biological line (n = 3 lines indicated by colour). Bars show mean ± s.e.m. Median internalised volume: 3.89 × 10-3 for MG, 3.36 × 10-3 for OPCs. Two-tailed Mann–Whitney U test, P = 0.61. Scale bars: 20 μm (a–e), 10 μm (magnifications of a–e).
