Fig. 7. Myocardial and perivascular HH signaling is required for tissue-specific VEGF ligand expression. (A,B) Cryosections of hearts stained with in situ probes for Ptch1. Although control hearts (A) contain expression of Ptch1 in both cardiomyoblasts (asterisk) and perivascular cells (arrow), Smo^mlc2v CKO hearts (B) express Ptch1 only in perivascular cells (arrow). (C-H) Immunofluorescent staining of cryosections for PECAM (red) and VEGF ligands (green). Compared with control hearts (C,E), which express VEGFA and VEGFB in both cardiomyoblasts (asterisk) and perivascular cells (arrow), Smo^mlc2v CKO hearts (D,F) express VEGFA and VEGFB in only perivascular cells (arrow). VEGFC is expressed in perivascular cells of both control (G) and Smo^mlc2v CKO (H) hearts (arrows). (I,J) Cryosections of hearts stained with an in situ probe for Ptch1. Although control hearts (I) express Ptch1 in both cardiomyoblasts (asterisk) and perivascular cells (arrow), Smo^dermo1 CKO hearts (J) express these transcripts in only the cardiomyoblast (asterisk). (K-P) Immunofluorescent staining of cryosections for PECAM (red) and VEGF ligands (green). Compared with control hearts (K,M), which express VEGFA and VEGFB protein in both cardiomyoblasts (asterisk) and perivascular cells (arrow), Smo^dermo1 CKO hearts (L,N) express VEGFA and VEGFB in only cardiomyoblasts (asterisk). VEGFC is expressed in perivascular cells of control (O), but not Smo^dermo1 CKO (P) hearts. (Q,R) Quantitative analysis of VEGF expression demonstrating statistically significant alterations in VEGF ligand expression in Smo^mlc2v CKO (Q) and Smo^dermo1 CKO (R) hearts compared with control hearts. Black bars represent myocardial expression and grey bars represent perivascular expression. Asterisk indicates a statistically significant difference compared with controls (P<0.01).