Immunohistochemical analysis of EPCR⁺ cells in E12.5 mouse FL. (A) EPCR⁺ cells (green) were detected in E12.5 mouse FL. Some cells were round (arrowheads), and others were spindle-shaped (asterisk). They were observed adjacent or connected to Lyve-1⁺ sinusoidal ECs (red), both inside and outside of the sinusoid lumen. Magnification is shown at ×120. (B-C) Some c-Kit⁺ cells (red) coexpressed EPCR (green) shown at arrowheads and located adjacent to the sinusoid (blue). Magnifications are ×240 for panel B and ×180 for panel C. (D) Nonlineage/CD41/CD48/Dlk-1–positive (blue) Sca-1⁺ (red) EPCR⁺ (green) cells shown at arrowheads were observed adjacent to the Lyve-1⁺ sinusoid (gray). Magnifications are ×240 (left) and ×150 (right). (E) APC (red) shown by asterisks distributed along the sinusoid (green) in FL. Magnification is ×40. (F-H) The perisinusoidal region, where EPCR⁺ cells (green) shown at asterisks are observed, is rich in ECM compounds (red), such as laminin (F), fibronectin (G), and matrix metalloproteinase-9 (MMP-9, H). Magnifications are ×120 for panel E, ×180 for panel F, and ×160 for panel G. (I) No specific spatial interaction was observed between Dlk-1⁺ hepatoblasts (red) and EPCR⁺ cells (green), shown at arrowheads. Magnification is ×80.