Figure 2

Changes in WSS modulate DLAV-PCV loop formation in a Notch-dependent manner. (A) Experimental design to genetically and pharmacologically manipulate hemodynamic WSS in zebrafish embryos. (B) In response to tail amputation, Gata1a morpholino oligonucleotides (MO) injection (1 mM) or 2,3-butanedione monoxime (BDM, 100 μM) treatment impaired vascular loop formation at 4 dpa (white arrows). Erythropoietin (epo) mRNA injection (10–20 pg/nl), isoproterenol treatment (100 μM) and 6% hydroxyethyl hetastarch promoted regeneration and vascular loop formation. Scale bar: 20 μm. (C)Gata1a MO and BDM treatment reduced endothelial tp1 activity and impaired regeneration, whereas epo mRNA injection or isoproterenol treatment up-regulated endothelial tp1 activity in the amputated site (white arrowheads) and promoted vascular loop formation at 4 dpa (white arrows). Scale bar: 20 μm. (D,E) Quantification of the proportion of embryos exhibiting loop formation and normalized area of vascular loop (^*p< 0.05, ^**p< 0.005 vs. control MO, n = 20 for each group to assess proportion, n = 5 for each group to assess area of vascular loop). Scale bar: 20 μm.