Fig. 2: RHI exposure induces distinct microglial phenotypes.
From: Repeated head trauma causes neuron loss and inflammation in young athletes
a, UMAP of microglia coloured by 11 Seurat clusters determined by unsupervised clustering. Mφ, macrophage; PVM, perivascular macrophage. b, Heat map of selected cluster DEGs annotated by function. Mono, monocyters; Ribo. bio., ribosome biogenesis; norm., normalized. c, Proportion of microglial subtypes per pathological group. Statistical analysis was performed using a chi-squared test. n = 28 individuals. Tests were two-tailed. Homeo, homeostasis. d, UMAP of each pathologic group. The dotted line depicts RHIM2/3 subtypes. e, hdWGCNA module analysis showing the Turquoise module localization to the RHIM2/3 subtype. f, GO analysis of the hdWGCNA Turquoise module. Statistics generated using gene set enrichment analyses (GSEA) and single-tailed hypergeometric test with Benjamini–Hochberg multiple hypothesis correction. ER, endoplasmic reticulum; miRNA, micro RNA; PID, Pathway Interaction Database. g–l, Violin plots of the Celda gene modules homeostasis (g), complement response (h), inflammation (i), hypoxia response (j), hypoxia response (k) and metabolic process (l). Colour represents the cellular subtype associated with the module. The black line represents the median. Statistical analysis performed by linear mixed effects modelling, correcting for patient-specific effects. Tests were two-tailed. n = 28 individuals. m, Quantification of grey matter sulcal homeostatic microglia (P2RY12hiIBA1+) with years of football play, coloured by pathological group. Statistical analysis performed by linear regression with age as a covariate. Each dot represents an individual donor. The black line represents linear model regression; the grey region shows the 95% confidence interval. The test was two-tailed. n = 37 individuals. n, Representative image of P2RY12 immunofluorescent labelling. Open arrowheads depict cells exhibiting high P2RY12 expression. Solid arrowheads depict cells exhibiting low P2RY12 expression. Scale bar, 50 μm. o, Representative image of SPP1+HIF1A+P2RY12+ microglia. Solid arrowheads indicate triple-positive cells. The white box indicates the inset displayed on the right. Scale bars: left, 50 μm; right, 5 μm. p,q, Quantification of the SPP1+HIF1A+ microglial fraction (p) and microglial SPP1 expression (q) in the grey matter sulcus with years of football play. Each dot represents an individual donor. n = 22 individuals. Coloured by pathological group status. Statistical analysis performed by linear regression. The test was two-tailed. The black line represents linear model regression; the grey region shows the 95% confidence interval.
