Fig. 1

Induction of IFNAR signalling within the brain parenchyma with peripheral mIFNα administration. a Schematic of treatment protocol. Mice (N = 2) were injected daily with varying doses of mIFNα for 7 days and sacrificed 3 h post final injection. Tissue samples were harvested following perfusion with ice-cold PBS to remove contamination from peripheral blood cells. b Interferon-stimulated gene (ISG) expression was assayed in the spleen using ddPCR, showing a dose-dependent effect of mIFNα on ISG expression. c ISG expression was similarly assayed in the cortex, showing a dose-dependent effect on ISG expression. d Serum mIFNα from PBS or mIFNα injected mice (N = 5 per group) was assayed using ELISA. Serum was collected 3 h post final injection. e Representative RNAscope images showing enriched ISG (Mx1, Rsad2) transcript abundance in Tmem119-positive microglia (white arrows) in mIFNα-treated mice. Inset in each image shows an example of ISG negative or positive microglia. f, g Quantitative analysis of RNAscope data showing significant ISG enrichment in both microglia (Tmem119 positive) and non-microglia (Tmem119 negative) cell types with mIFNα exposure (N = 6 per condition). Scale bar = 50 μm. **p < 0.01; ***p < 0.001; Student’s t test or Mann-Whitney U test, assessed by normality of data distribution