Embryonic vascular disruption adverse outcomes: Linking high throughput signaling signatures with functional consequences

- Two anti-angiogenic agents were tested across ToxCastDB HTS platforms and in vitro functional assays.
- 5HPP-33 and TNP-470 were identified as putative vascular disruptive compounds in ToxCastDB HTS assays.
- Both agents disrupted angiogenesis in the rat aortic explant assay differing in phenotype and potency.
- 5HPP-33 was embryolethal at μM, while TNP-470 produced caudal embryo defects at nM concentrations.
- Supplementing HTS with complex in vitro assays aids mechanism identification and test prioritization.

Embryonic vascular disruption is an important adverse outcome pathway (AOP) as chemical disruption of cardiovascular development induces broad prenatal defects. High throughput screening (HTS) assays aid AOP development although linking in vitro data to in vivo apical endpoints remains challenging. This study evaluated two anti-angiogenic agents, 5HPP-33 and TNP-470, across the ToxCastDB HTS assay platform and anchored the results to complex in vitro functional assays: the rat aortic explant assay (AEA), rat whole embryo culture (WEC), and the zebrafish embryotoxicity (ZET) assay. Both were identified as putative vascular disruptive compounds (pVDCs) in ToxCastDB and disrupted angiogenesis and embryogenesis in the functional assays. Differences were observed in potency and adverse effects: 5HPP-33 was embryolethal (WEC and ZET); TNP-470 produced caudal defects at lower concentrations. This study demonstrates how a tiered approach using HTS signatures and complex functional in vitro assays might be used to prioritize further in vivo developmental toxicity testing.