Fig. 4: Integrin-dependent adhesion confines a mature MC subset to arterioles.
From: Slow integrin-dependent migration organizes networks of tissue-resident mast cells
a, Workflow for scRNA-seq analysis of MCs from dermal ear skin. b, UMAP of single-cell transcriptomes of sorted CD45+Lin−YFP+ cells (WT and Tln1∆MC MCs combined, n = 1,895 cells derived from three WT and three Tln1∆MC mice) highlighting RaceID3 clusters. Numbers denote clusters. c, UMAP of single-cell transcriptomes of MCs highlighting the sources or origins of the cells, that is, which mice (WT or Tln1∆MC) the cells were isolated from. d, Heat map showing the fractions of WT and Tln1∆MC MCs in clusters, which were significantly enriched for either WT or Tln1∆MC cells; P < 0.05. Data were analyzed by one-tailed hypergeometric test. e, Box plots show analysis of clusters 1, 5, 8 and 9. MC marker expression was downregulated in MCs from Tln1∆MC relative to WT mice. Boxes indicate first and third quartiles, and the black line indicates the median. Whiskers indicate 5% and 95% quantiles. For all comparisons, Benjamini–Hochberg-corrected P < 0.05; Mcpt4, P = 2.9 × 10–31; Cpa3, P = 2.5 × 10–69; Cma1, P = 3.8 × 10–13; Mcpt6, P = 4.1 × 10–23. f, UMAP for Cma1 and Mcpt6 expression. The color bar indicates normalized transcript counts. g, FISH of Cma1 mRNA in ear skin whole mounts of adult WT mice (left) and postimaging analysis of Cma1 expression in arteriolar (arteriol.) versus interstitial (interst.) MCs (right). h–j, Quantification of Cma1 mRNA (h) and Mcpt6 mRNA (i) FISH signal per cell volume and comparison between arteriolar and interstitial MCs. Dots represent individual MCs from one of four biological replicates; n = 17 (arteriolar MCs) and 38 (interstitial MCs; h) and n = 18 (arteriolar MCs) and 28 (interstitial MCs; i). Bars indicate means; ***P < 0.0001, two-sided t-test (h); ***P = 0.0009, two-sided U-test (i). j, Ratios of arteriolar to interstitial mRNA signals were calculated for four mice. k–m, MCPT6 protein expression in dermal MCs of adult WT mice. k, Immunofluorescence staining for MCPT6 in ear skin whole-mount tissue. An overview image (left) and MCs in the periarteriolar space (right) are shown. The heat map bar shows MCPT6 fluorescence signal intensity. l, Quantification of MCPT6 fluorescence. The mean intensity (MI) of MCPT6 fluorescence was measured per cell in arteriolar versus interstitial MCs. Quantification is displayed for one independent experiment, and each dot represents one MC; n = 30 (arteriolar MCs) and 21 (interstitial MCs). Bars indicate means; ***P < 0.0001, two-sided t-test. m, Ratios of arteriolar to interstitial MCPT6 signal were calculated for five mice; scale bars, 20 µm (g), 100 µm (k, left) and 150 µm (k, right).
