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. 2019 Sep 6;28(1):217–234. doi: 10.1016/j.ymthe.2019.09.003

Figure 5.

Figure 5

Local and Global Connections after Astrocyte-to-Neuron Conversion

(A and B) Brain slice recording on NeuroD1-converted neurons (GFP) detected repetitive action potential firing (60 dpi, n = 22). (C) Representative traces of spontaneous excitatory (sEPSCs) and inhibitory synaptic events (sIPSCs) recorded in NeuroD1-GFP labeled neurons (60 dpi). (D) Quantification of the frequency of both sEPSCs and sIPSCs in cortical slices without injury (white bar), or with ischemic injury (black bar, GFP control; striped bar, NeuroD1 group). Note that NeuroD1 group showed significantly higher frequency of both sEPSCs and sIPSCs than the control group. Neurons in the control group were the surviving neurons after ischemic injury, not labeled by GFP. Amplitude showed no difference between the control group and NeuroD1 group: EPSC, control, 19.3 ± 2.6 pA; NeuroD1, 16.6 ± 1.3 pA; p > 0.05. IPSC, control, 20.6 ± 1.6 pA; NeuroD1, 21.7 ± 2.0 pA; p > 0.05. n = 22 for control group, and n = 25 for NeuroD1 group. Student’s t test. Electrophysiological properties: Input resistance, non-stroke group 133.8 ± 11.9 MΩ, GFP control group 236.8 ± 27.3 MΩ, NeuroD1 group 180.2 ± 23.3 MΩ; Capacitance, non-stroke group 139.2 ± 10.2 pF, GFP control group 108.0 ± 19.4 pF, NeuroD1 group 128.4 ± 8.5 pF; Resting membrane potential, non-stroke group −70.0 ± 1.9 mV, GFP control group −67.4 ± 1.0 mV, NeuroD1 group −68.1 ± 0.9 mV. n = 21 for non-stroke group, n = 28 for GFP control group, and n = 42 for NeuroD1 group. (E) Representative images illustrating distal axonal projections from NeuroD1-converted neurons. Serial sagittal sections (17 dpi), from medial (M, lower left) to lateral (L, upper right), showing converted neurons in the cortex (inset 1), axonal bundles in the striatum (inset 2), thalamus (inset 3), and hypothalamus (inset 4). Scale bars, 1,000 μm for sagittal images and 40 μm for inset images. (F) CTB retrograding tracing experiment (shown in upper panel, see detail in Supplemental Information) indicate the NeuroD1 converted cells could be labeled by CTB dye. Scale bar, 10 μm.