Figure 3. Endocardial cells contribute to cardiac tissue macrophages.

A, B. Immunofluorescent staining for CD45 (red), cTnT (white) and YFP (green) of Nfatc1^cre/+; Rosa26^{YFP reporter/+} cushion mesenchyme of AV canal (A) and outflow tract (B) at E13.5. YFP-labeled CD45⁺ myeloid cells with mesenchymal morphology are enriched at the border of cushion mesenchyme and cTnT⁺ myocardium. Scale bar = 10 μm

C-Y. Immunofluorescent staining for macrophage markers (CD68, F4/80 and CD206; red) of the cushion and valvular mesenchyme of Nfatc1^cre/+; Rosa26^{YFP reporter/+} mouse at E10.5 (C-E), E15.5 (F-I), P1 (J-M), P8 (N-Q), P28 (R-U) and adult (V-Y) stages. Nfatc1-derived macrophages are found throughout embryonic and postnatal stages. Scale bar = 10 μm. See also FigureS1