FS145, the first flea-derived disintegrin, inhibits angiogenesis through specifically binding integrin αvβ3.

FS145, a protein containing a WGD motif, was previously described from the salivary transcriptome of the flea Xenopsylla cheopis. Nevertheless, its biological function and complete structure are still uncertain. Herein, FS145 was confirmed to adopt a common αββ structure with the WGD motif exposed on its surface and located right at the top of a loop composed of residues 72–81. Furthermore, FS145 dose-dependently inhibited the proliferation, adhesion, migration, and tube formation of HUVECs by not only binding to integrin α v β 3 but also by subsequently inactivating the FAK/Src/MAPK pathway along with the reduction of the expression of MMP-2, MMP-9, VEGFA, bFGF, Ang2, Tie2, HIF-1α, and FAK. Moreover, FS145 also inhibited aortic vessel sprout and showed strong anti-angiogenic activities as assessed ex vivo, by employing the rat aortic ring assay, chick embryo chorioallantoic membrane, and zebrafish embryo models. Altogether, our results suggest that FS145 suppresses angiogenesis ex vivo and in vitro by blocking integrin α v β 3. The current study reveals the first anti-angiogenesis disintegrin with WGD motif from invertebrates and provides a beneficial pharmacological activity to inhibit abnormal angiogenesis. [ABSTRACT FROM AUTHOR]