Vascular Endothelial Growth Factor VEGF-like Heparin-Binding Protein from the Venom of Vipera aspis aspis (Aspic Viper)

Abstract

The heparin-binding dimeric hypotensive factor (HF) was purified from Vipera aspis aspis (Aspic viper) venom [Komori, Y. and Sugihara, H. (1990) Toxicon 28, 359-369]. In this study, the amino acid sequence, and structure and function of HF, were elucidated. By electrospray ionization mass spectrometry (ESI-MS), the molecular weight of HF was determined to be 25 072.1. The complete amino acid sequence of HF was determined by Edman sequencing of the S-pyridylethylated HF and its peptides derived from enzymatic digestion. The theoretical molecular mass calculated from the primary structure agrees well with the molecular weight determined by ESI-MS. HF consists of two homogeneous monomers bound covalently. The monomer with an N-terminal blocked by pyroglutamic acid contains 110 amino acid residues, including eight cysteine residues, two of which are considered to be involved in intermolecular disulfide bonds. Sequential homology search revealed that the primary structure of HF is similar to that of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) with a sequential homology of 45 and 22%, respectively. When injected intradermally into a rat, an increase in capillary permeability was observed with HF or VEGF. On the other hand, only HF exerted a strong hypotensive effect after intravenous injection of samples into a rat. Purified HF has a mitogenic effect on endothelial cells. Through the use of bovine aortic endothelial cells (BAEC), the half-maximal mitogenic concentration of HF was determined to be 5-5. 5 nM (125-138 ng/mL). Similarly, VEGF had a mitogenic concentration at 0.5-1 nM. When incubated with HF and cycloheximide or HF and heparin, the cell growth was inhibited, suggesting that the mechanism of action of HF is similar to that of VEGF.

Complete Structure of an Increasing Capillary Permeability Protein (ICPP) Purified from Vipera lebetina Venom

“…This protein consists of two homodimers of 110 amino acids having a molecular mass of 25115 Da. ICPP shares the highest sequence identity with HF, the hypotensive factor purified from V. aspis aspis (23), and the recently identified svVEGF from B. insularis pit viper venom (24). ICPP, together with the other snake svVEGFs, shares about 50% identity with human VEGF-A (22).…”

“…In this context, it is remarkable to see the emergence of a new set of selected molecules with permeability capacity in snake venoms. ICPP, an increasing capillary permeability protein of V. lebetina venom, is indeed a VEGF-related molecule highly homologous to the HF with vascular permeability activity (23). During the preparation of this manuscript, another report demonstrated the expression of related VEGF molecules in the venom of Bothrops jararaca (pit viper) (24), a result extending the notion that many snakes have evolved to specifically express in their venoms VEGF-like molecules, the most potent permeability factors described so far in vertebrates.…”

“…The mitogenic activity of HF was 5-10 times lower than that of VEGF and was inhibited by cycloheximide. The authors speculated that this protein may induce a signaling response and increase protein synthesis in endothelial cells, but studies examining the mechanism of action have not been reported (23).…”

“…Fig. 2 shows the alignment of amino acid sequences of ICPP with those of human VEGF (22), an HF purified from Vipera aspis aspis (23), and svVEGF derived from Bothrops insularis (Fig. 2, Bins svVEGF) and Bothrops jararaca (Fig.…”

Snake Venom Vascular Endothelial Growth Factors (VEGFs) Exhibit Potent Activity through Their Specific Recognition of KDR (VEGF Receptor 2)

“…VEGF homologous potent hypotensive factor (HF) was isolated from Vipera aspis aspis (Aspic viper) venom (20). It has been reported that HF induces dramatic hypotension compared with VEGF 165 and other growth factors (20), but the detailed characterization of its potent activity remains to be resolved.…”