AUTHOR=Subramaniam Saravanan , Liu Jiandong , Fletcher Craig , Ramchandran Ramani , Weiler Hartmut 

TITLE=Coagulation Factor IIIa (f3a) Knockdown in Zebrafish Leads to Defective Angiogenesis and Mild Bleeding Phenotype

JOURNAL=Frontiers in Cell and Developmental Biology

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/cell-and-developmental-biology/articles/10.3389/fcell.2022.852989

DOI=10.3389/fcell.2022.852989

ISSN=2296-634X

ABSTRACT=<p>Tissue factor (TF) is crucial for embryogenesis, as mice lacking TF are embryonically lethal (E10.5). This lethality may be attributed to defects in vascular development and circulatory failure, suggesting additional roles for TF in embryonic development beyond coagulation. In this study, we characterized the role of one of the TF paralogs (<italic>f3a</italic>) using a zebrafish model. The expression of <italic>f3a</italic> during embryonic developmental stages was determined by RT-PCR. Spatiotemporal expression pattern of <italic>f3a</italic> revealed (high expression from 28 to 36 hpf) the role of in the development of the yolk sac, circulation, and fins. Morpholinos (MO), an antisense-based oligonucleotide strategy, was used to knockdown <italic>f3a</italic> and examined for defects in morphological appearance, bleeding, and vascular patterning. <italic>f3a</italic> MO-injected embryos showed morphological abnormalities, including shorter body lengths and crooked tails. O-dianisidine staining showed <italic>f3a</italic> MO-injected embryos exhibited bleeding in the trunk (5.44%) and head (9.52%) regions. Imaging of endothelial-specific transgenic lines (<italic>flk1:egfp-NLS/kdrl:mCherry-CAAX</italic>) showed a 3-fold decreased caudal vein plexus (CVP) in <italic>f3a</italic> morphants versus controls at 48 hpf, suggesting a potential role for <italic>f3a</italic> in angiogenesis. These findings confirm that <italic>f3a</italic> is essential for angiogenesis, in addition to its involvement in hemostasis.</p>