# Insights into the pro-angiogenic effect of hydroxysafflor yellow A (HSYA): targeting HIF-1α and MMP9 in HMEC-1

## TL;DR

This study shows that hydroxysafflor yellow A promotes blood vessel growth in human endothelial cells by targeting HIF-1α and MMP9.

## Contribution

The novel contribution is identifying HIF-1α and MMP9 as key molecular targets of HSYA in promoting angiogenesis.

## Key findings

- HSYA promotes angiogenesis in HMEC-1 cells without affecting cell viability.
- Molecular docking and experiments confirm HSYA interacts with HIF-1α and MMP9.
- HSYA modulates multiple pathways including HIF-1 and VEGF in angiogenesis.

## Abstract

Angiogenesis is a fundamental physiological process mediating vascular network formation, represents a critical therapeutic target for ischemic diseases and tumor neovascularization. Xuefu Zhuyu decoction (XFZYD), a classical formula for promoting blood circulation and resolving stasis, demonstrates pro-angiogenic effect with safflower functioning as the sovereign herb. Hydroxysafflor yellow A (HSYA), the primary bioactive constituent of safflower, exerts potent angiogenesis modulation, defining its pharmacological significance.

In this study, in vitro tubulogenesis assay and cytocompatibility analysis were employ on human microvascular endothelial cell (HMEC-1), followed by target prediction via network pharmacology and molecular docking; immunoblotting analysis was performed to experimentally validate the pro-angiogenic molecular mechanism of HSYA.

HSYA exerted concentration-dependent pro-angiogenic effects on HMEC-1 cells over 24 h without compromising cell viability (p > 0.05) across 0–200 μM. 121 potential targets of HSYA within the angiogenesis regulatory network were identified. Functional enrichment analysis revealed fluid shear stress, lipid metabolism, HIF-1, PI3K-Akt, and VEGF signal pathways as primary regulatory pathways. 8 hub targets derived from the protein-protein interaction (PPI) network were subjected to molecular docking. High-affinity interactions were observed for key angiogenesis regulators: MMP9 (−7.6 kcal·mol−1), and HIF-1α(−4.5 kcal·mol−1), which were functionally validated by immunoblotting analysis, preliminary demonstrating the mechanism of HSYA-mediated angiogenesis promotion.

HSYA demonstrates significant pro-angiogenic activity on HMEC-1. Mechanistically, HSYA modulates multiple signaling pathways, with HIF-lα and MMP9 demonstrating regulatory significance. These findings suggest a molecular basis for HSYA’s therapeutic potential in ischemic vascular pathologies.