Heparan Sulfate Regulates VEGF165- and VEGF121-mediated Vascular Hyperpermeability

Abstract

VEGF was first described as vascular permeability factor, a potent inducer of vascular leakage. Genetic evidence indicates that VEGF-stimulated endothelial proliferation in vitro and angiogenesis in vivo depend on heparan sulfate, but a requirement for heparan sulfate in vascular hyperpermeability has not been explored. Here we show that altering endothelial cell heparan sulfate biosynthesis in vivo decreases hyperpermeability induced by both VEGF 165 and VEGF 121 . Because VEGF 121 does not bind heparan sulfate, the requirement for heparan sulfate suggested that it interacted with VEGF receptors rather than the ligand. By applying proximity ligation assays to primary brain endothelial cells, we show a direct interaction in situ between heparan sulfate and the VEGF receptor, VEGFR2. Furthermore, the number of heparan sulfate-VEGFR2 complexes increased in response to both VEGF 165 and VEGF 121 . Genetic or heparin lyase-mediated alteration of endothelial heparan sulfate attenuated phosphorylation of VEGFR2 in response to VEGF 165 and VEGF 121 , suggesting that the functional VEGF receptor complex contains heparan sulfate. Pharmacological blockade of heparan sulfate-protein interactions inhibited hyperpermeability in vivo, suggesting heparan sulfate as a potential target for treating hyperpermeability associated with ischemic disease.

VEGF-A121a binding to Neuropilins – A concept revisited

“…43 There are effects downstream of receptor binding too: in vivo alteration of HS biosynthesis, or inhibition of the HS-VEGFR interaction, inhibit VEGF-A121a-induced hyperpermeability; and removal of the HS chains decreases VEGF-A121a/VEGFR2/NRP1 and VEGF-A165a/NRP1/VEGFR2 assembly level and attenuates effective VEGFR2 phosphorylation in endothelial cells. 39 …”

Heparan Sulfate Proteoglycans

“…Floxed allele: decreased chemokine transcytosis and presentation and neutrophil infiltration in Tie2Cre mice ; decreased allergen-induced airway hyperresponsiveness and inflammation because of reduction in recruitment of eosinophils, macrophages, neutrophils, and lymphocytes in Tie2Cre mice (Zuberi et al 2009); decreased pathological angiogenesis in Tie2Cre mice (Fuster et al 2007); decreased vascular VEGF-induced hyperpermeability (Xu et al 2010a); decreased vascular smooth muscle cell proliferation, vessel size, and vascular remodeling after arterial injury in SM22aCre mice (Adhikari et al 2010a); mild effect on T-cell response in Tie2Cre;Ndst2 2/2 mice (Garner et al 2008); defective lacrimal gland development and Fgf10-Fgfr2b complex formation and signaling in LeCre mice ; defective lobuloalveolar development in mammary gland (Crawford et al 2010).…”

Electrospun PHEA-PLA/PCL Scaffold for Vascular Regeneration: A Preliminary in Vivo Evaluation

“…Although the scaffold was pervious only for a month, we had no evidence of early thrombosis phenomena, despite the complete absence of anticoagulant therapy. Heparin also had an important role in guiding vascular endothelialization and by stimulating numerous growth factors [42,81]. This would allow the circulating stem cells to engraft to the implanted tissue and promote the regeneration of a fabric (regarding mechanical and biologic characteristics) similar to that of the host organism.…”