MRC1 and Patent ductus arteriosus: Consistently, M2 marker genes such as Fizz-1, Mrc-1, and Il-10 were significantly less upregulated in M1-like macrophages following co-culturing with PDA cells in presence of RGD peptides and TGF-βRII-blocking antibodies compared to M1-like macrophage following co-culturing with PDA cells in absence of RGD peptides and TGF-βRII-blocking antibodies (Fig. 4e).