Fig. 1: Acute consequence of ablating multiple contiguous pericytes.

a In vivo two-photon imaging through a chronic cranial window in anesthetized PDGFRβ-tdTomato mice. b Capillary bed with vessels labeled green with intravenous (i.v.) dye, FITC-dextran (70 kDa), and pericytes genetically labeled in red. The inset shows the structure of capillary pericytes. Representative of 12 PDGFRβ-tdTomato mice in this study. c A capillary pericyte targeted for two-photon ablation encircled in yellow. Ablative line-scanning is restricted to the pericyte soma. Post-ablation image shows loss of fluorescence from targeted pericyte, including its processes, within minutes post-ablation. Neighboring pericytes are unaffected. Representative of >42 pericyte ablations. d Schematic showing metrics collected following ablation of three contiguous pericytes. Left, targeted pericytes are marked with asterisks. Right, metrics include total capillary length uncovered, number of remodeling pericytes, and number of remodeling pericyte processes. e,f Before and 5 min after triple pericyte ablation in adult and aged animal. Arrowheads indicate targeted pericyte somata, and dotted magenta line outlines approximate regions of uncovered endothelium. Inset shows a magnified region with pericyte ablation and uncovered territory 5 min afterwards. Each example is representative of 7 experiments per age group. Comparison of vascular metrics between adult and aged mice after triple pericyte ablation. g Total capillary length uncovered; t(12) = 1.790, p = 0.0988. h Number of fully and partially uncovered capillary segments; t(12) = 0.1936, p = 0.8497. i Range of capillary segment lengths; t(195) = 0.2325, p = 0.8164. All are unpaired t tests (two-sided), for n = 7 triple pericyte ablations (6 adult mice), 7 triple pericyte ablations (6 aged mice) for g and h and n = 99 capillary segments over 6 adult mice, n = 98 capillary segments over 6 aged mice for i. Data are shown as mean ± SD. Ns = non-significant. Comparison of pericyte metrics between adult and aged mice after triple pericyte ablation. j Number of remodeling pericytes; t(12) = 0.6030, p=0.5577. k Number of remodeling pericyte processes; t(12) = 0.7206, p = 0.4850. Unpaired t tests for n = 7 triple pericyte ablations (6 adult mice), 7 triple pericyte ablations (6 aged mice). Data are shown as mean ± SD.