Extended Data Fig. 4: Generation of mice with striatum-specific microglia depletion.
From: Negative feedback control of neuronal activity by microglia
a, b, (left), The striatum-specific microglia depletion was achieved by breeding Il34fl/fl mice to Drd1aCre/+ or Drd2Cre/+ mice to generate Il34fl/fl; Drd1aCre/+ (a, green) and Il34fl/fl; Drd2Cre/+ mice (b, grey). Right, dot plots show relative expression of Il34 mRNA in the striatum normalized to Gapdh (a, n = 6 and 7 mice, P < 0.0001; b, n = 4 mice, P = 0.0004, unpaired two-tailed t-test). c, Representative striatal images of sagittal brain slices from Il34fl/fl, Il34fl/fl; Drd1aCre/+ and Il34fl/fl; Drd2Cre/+ mice following immunofluorescent staining for P2RY12 (microglia, green) and DAPI (nuclei, blue) (scale bar = 50μm). d, e, Dot plots show the average microglia density per mm2 per mouse per specific region in the hippocampus of Il34fl/fl; Drd1aCre/+ (d) and Il34fl/fl; Drd2Cre/+ mice (e) compared to littermate controls (d, n = 3 mice, DG: P = 0.88, CA3: P = 0.85, CA1: P = 0.1; e, n = 3 mice, DG: P = 0.69, CA3: P = 0.56, CA1: P = 0.72; unpaired two-tailed t-test). f, g, Dot plots showing total distance travelled in response to D1 agonist (SKF81297, 3 mg kg–1, i.p.) in one hour in the open field for Il34fl/fl; Drd1aCre/+ (f) and Il34fl/fl; Drd2Cre/+ mice (g) compared with littermate controls (f: n = 8 and 9 mice, P = 0.034 g: n = 8 mice, P = 0.0087, unpaired two-tailed t-test). h, Percentage of mice seizing 30 min after administration of picrotoxin (1 mg kg–1, i.p.) shown as a bar graph (n = 21, 9, and 8 mice; P = 0.80, Chi-squared test). DG: dentate gyrus. i, Microglia-neuron ratio defines the threshold of D1 neuron activation by D1 agonist. Bar graph shows the percentage of mice with stage IV-V seizures in response to D1 agonist (4 mg kg–1, i.p.) in control, Il34fl/fl; Drd1aCre/+, and microglia deficient mice (n = 11, 13, and 9 mice; right, P = 0.0005, Chi-squared test). While all mice display an increased seizure response to 5 mg kg–1D1 agonist treatment, only microglia deficient (99% reduction of microglia), but not Il34fl/fl; Drd1aCre/+ (60% reduction of microglia in the striatum) display an increased seizure response at 4 mg kg–1D1 agonist treatment. Data shown as mean ± s.e.m.
