Pericyte-macrophage interactions via the IL34-CSF1R axis. (A) CellChat analysis of 1,592 naive DRG cells from a publicly available dataset (Avraham et al., 2020). Predicted cell–cell interactions via the IL34-CSF1R axis. (B) Heatmap visualizing communication probability between sender (y-axis) and receiver (x-axis) cells for the IL34-CSF1R axis using CellChat. (C) mRNA expression of indicated genes in the dataset used for CellChat. (D and E) Identification of capillary-wrapping CD13⁺GFP⁺p75⁻ pericytes (PC) in Pdgfrb^GFP mice. Scale bar, 50 μm. (F) Identification of p75⁺GFP⁺CD13⁻ fibroblasts (FB) in Pdgfra^H2GFP mice. Scale bar, 50 μm. (G) Z-stack and 3D rendering of Iba1⁺ macrophage, CD13⁺ pericyte, and p75⁺ fibroblast contacts on CD31⁺ DRG capillaries. Scale bars, 10 μm. (H) Localization of IL34 staining in GFP⁺ pericytes in Pdgfrb^GFP mice but absence from GFP⁺ fibroblasts in Pdgfra^H2GFP mice. Scale bars, 25 μm (top) and 10 μm (bottom). (I) IL34 staining in mice fed control or PLX3397 (290 ppm) chow for 7 d n = 5 mice/group. The experiment was performed twice. Student’s unpaired t test. *P < 0.05. Scale bar, 50 μm. (J) Analysis of coverage of CD31⁺ capillaries by CD13⁺ pericyte staining in Pdgfb^ret/ret and littermate Pdgfb^ret/+ mice. Arrowheads indicate capillaries without pericyte coverage. Student’s unpaired t test. ***P < 0.001. Scale bar, 50 μm. (K) Analysis of contact between CD13⁺ pericytes and Iba1⁺CD163⁺ or Iba1⁺CD163⁻ macrophage subsets in Pdgfb^ret/ret and littermate Pdgfb^ret/+ mice. n = 3 mice/group. Sidak’s multiple comparisons test. **P < 0.01, ***P < 0.001.