Abstract: In this study, the total sugar, protein, 3,6-anhydro galactose and sulfate contents, apparent molecular mass and monosaccharide composition of porphyran isolated from Porphyra yezoensis were analyzed. The pro-angiogenic activity and underlying mechanism of porphyran were further investigated using human umbilical vein endothelial cells (HUVECs) as an in vitro angiogenesis model. The effect of porphyran on the cell viability of HUVECs was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell adhesion and migration capacity were evaluated using cell adhesion and wound healing assays. The number of lumens formed by HUVECs was analyzed using in vitro tube formation assay. The expression levels of E-cadherin and N-cadherin in HUVECs were analyzed by Western Blotting, and the pro-angiogenic mechanism of porphyran in HUVECs was explored using specific inhibitors of mitogen-activated protein kinases (MAPKs) and vascular endothelial growth factor (VEGF) receptor tyrosine kinase inhibitors. The results showed that porphyran contained (77.48 ± 2.62)% total sugar, (3.24 ± 0.58)% protein, and (20.30 ± 1.06)% 3,6-anhydrogalactose as well as (20.78 ± 3.31)% sulfate groups. The apparent molecular mass of porphyran was 39.81 kDa. Porphyran was mainly composed of galactose, 3,6-anhydrogalactose and sulfate groups, suggesting it to be a sulfated galactan. Furthermore, porphyran treatment in the concentration range of 0–200 μg/mL had no significant toxicity no HUVECs, but instead promote cell proliferation, adhesion, migration, and vascular network formation. Further studies demonstrated that porphyran exerted its pro-angiogenic effect primarily by mediating the down-regulation of E-cadherin expression and the up-regulation of N-cadherin expression through the c-Jun N-terminal kinase (JNK) MAPK and VEGF receptor signaling pathways. In conclusion, porphyran has pro-angiogenic potential, which will provide a scientific basis for the development of porphyran as a novel pro-angiogenic factor and the precision nutrition-guided deep processing and high-value utilization of the red seaweed P. yezoensis.

Key words: porphyran; human umbilical vein endothelial cells; cell migration; pro-angiogenic activity