Cd34-CreER labeled periductal and periportal-venous fibroblasts and a subset of immune cells, but not pericentral-venous fibroblasts, endothelial cells, or any other cell types in normal liver. (A) Confocal images of liver sections (15 µm) showing the protein expression patterns of CD34. Blood vessels and bile ducts were labeled by anti-CD31 and anti-Epcam antibodies, respectively. Scale bar = 200 µm (n = 3 mice from three independent experiments). All Cd34^creER;R26^tdTomato mice used in B–M were treated with tamoxifen for three consecutive days at 6 wk of age (n = 3–5 mice per condition from three independent experiments). (B) Confocal images showing Tomato expression in periductal and periportal-venous cells, but not pericentral-venous cells in Cd34^creER;R26^tdTomato livers. Blood vessels and bile ducts were labeled by anti-CD31 and anti-Epcam antibodies, respectively. Scale bar = 200 µm. (C) Confocal imaging revealed overlapping Tomato and CD34 expression (detected by anti-CD34 antibody) in the liver from 8-wk-old Cd34^creER;R26^tdTomato mice. Scale bar = 50 µm. (D–I) Confocal images showing Tomato expression in Col1⁺ (D) and Thy-1⁺ fibroblasts (E), but not in Myh11⁺ VSMCs (F), Reln⁺ HSCs (G), Gpm6a⁺ mesothelial cells (H), or F4/80⁺ Kupffer cells (I) in Cd34^creER;R26^tdTomato livers. Scale bar = 50 µm. (J) Confocal image showing Tomato expression in CD45⁺ immune cells in Cd34^creER;R26^tdTomato livers. Scale bar = 50 µm. (K) Flow cytometric analysis showing the expression of Tomato in a subset of immune cells in the liver of Cd34^creER;R26^tdTomato mice. (L) Confocal image showing intravascular and extravascular localization of Tomato⁺ cells in Cd34^creER;R26^tdTomato livers. Scale bar = 50 µm. Arrow depicts the extravascular Tomato⁺ cell; arrowhead depicts the intravascular Tomato⁺ cell. (M) Flow cytometric analysis showing that Tomato was not expressed in VE-cadherin⁺ endothelial cells of Cd34^creER;R26^tdTomato mouse livers.