Fig. 2: Structural GABAergic neuron-to-glioma synapses in DMG.

a, Immuno-electron microscopy of SU-DIPG-VI cells with GFP-tagged GABRG2 xenografted into the mouse hippocampus. The white arrowheads denote immunogold labelling of GFP (glioma GABRG2). Presynaptic neurons are shaded purple, and glioma cells are shaded green. Scale bars, 100 nm. n = 39 synapses identified from 4 mice. b, Schematic of colours representing structures in GABAergic neuron-to-glioma synapses imaged in panels c,d, including neurons (red), gliomas (blue), presynaptic puncta (white) and postsynaptic puncta (green). The schematic was created using BioRender (https://biorender.com). c, Representative confocal micrograph 3D reconstructions of GABAergic neuron-to-glioma synaptic puncta in neuron–glioma co-cultures. Patient-derived DMG cells (SU-DIPG-XIII-FL; nestin in blue) expressing GABRG2–GFP (postsynaptic marker in green) colocalize with the presynaptic marker synapsin (white) on rat hippocampal neurons (neurofilament in red). Scale bars, 2 µm. d, Representative confocal micrograph 3D reconstructions of GABAergic neuron-to-glioma synaptic puncta in patient-derived xenografts. Postsynaptic gephyrin (green) on GFP-expressing patient-derived DMG cells (SU-DIPG-XIII-FL; GFP in blue) colocalizes with the presynaptic marker VGAT (white) on neurons (DLX–mCherry in red) in the mouse hippocampus. Scale bars, 2 µm. e, Representative confocal micrograph 3D reconstruction of a glioma cell (blue) with several gephyrin puncta (green) colocalized with presynaptic VGAT puncta (white). Colocalized puncta are indicated with yellow arrows and some examples are highlighted in yellow boxes. Scale bars, 2 µm.