| |
Fig. 5. Disrupted Lhx9-integrin signaling alters epicardial ECM environment. (A-E) Transverse cardiac agarose sections from control (A,B) and Lhx9-
depleted (C,D) Xla.Tg(Cardiac-actin:GFP)Mohun embryos at stage 45. Nuclei stained with DAPI (blue), GFP labels cardiomyocytes (green) and
immunohistochemical expression for Itgβ1 (B,D, magenta) to label epicardial cells and fibronectin (B′,D′, red). Threshold binary images (ImageJ) in B′ and D′
show Itgβ1-positive epicardial cells used to quantify pixel intensity in B′ and D′. (E) Pixel intensity (integrated density) levels for fibronectin from five control and
10 Lhx9-depleted embryos, P=0.064 by two-tailed Student’s t-test. (F-K) Transverse cardiac agarose sections from control (F,H,I) and Lhx9-depleted (G,J,K)
embryos at stage 45. Nuclei stained with DAPI (blue) and immunohistochemical stain for tropomyosin (cardiomyocytes, F,G, green), laminin (F,G, magenta)
and β-dystroglycan (H′-K′, magenta). Tcf21 expression (H-K) demonstrates PE cell attachment to the heart. Red boxes in H,J are magnified in I,K; white boxes in
H′,J′ are magnified in I′,K′. White arrowheads label PE (F′,G′,I′,K′) and migrating epicardial cells (F′,G′). Yellow arrowheads label expression in endocardial
tissue (B′,D′,I′,K′). v, ventricle. Representative images from seven (laminin) and six (β-dystroglycan) embryos per condition, from two independent experiments. |
