“…These include RA-inducible factor FGF9, which indirectly supports coronary development through promoting cardiomyocyte proliferation and myocardial expression of VEGF (Lavine et al, 2006). Therefore, the effect of altered RA-signaling on coronary development in vivo is likely to reflect the aggregated impact of altered RA on myocardial expansion, vascular development and fetal erythropoiesis (Bohnsack, Lai, Dolle, & Hirschi, 2004;Brade et al, 2011;Canete, Cano, Munoz-Chapuli, & Carmona, 2017;Chanda, Ditadi, Iscove, & Keller, 2013;Pawlikowski, Wragge, & Siegenthaler, 2019). APJ is specifically expressed in sinus venosus-derived coronary vessels, and APJ signalling via its alternate ligand, elabela, was required for their angiogenic sprouting (Chen et al, 2014;Sharma, Ho, et al, 2017).…”