Effects of arginine‐glycine‐aspartic acid (RGD) containing snake venom peptides on parthenogenetic development and in vitro fertilization of bovine oocytes

Abstract

The ability of synthetic arginine-glycine-aspartic acid (RGD)-containing peptides to induce intracellular calcium transients similar to those observed at fertilization by spermatozoa in the bovine has been reported (Campbell et al., 2000: Biol Reprod 62:1702-1709; Sessions et al., 2006. Mol Reprod Dev). These results also indicated the ability of synthetic RGD-containing peptides to induce activation and subsequent parthenogenetic development to the blastocyst stage, although, at numbers lower than observed with control in vitro fertilization (IVF). Evidence has been provided indicating the important effect of surrounding regions on the biological activity of the RGD sequence (Zhu and Evans, 2002; Sessions et al., 2006). The current experiments were designed to use natural RGD-containing sequences (disintegrins) to understand their effects. A total of three RGD-containing snake venom peptides (Kistrin (K), Elegantin (Ele), and Echistatin (Ech)) and one nonRGD-containing venom (Erabutoxin B (EB; control) were used at three concentrations (0.1, 1, and 10 micro g /ml) to induce parthenogenetic development to the blastocyst stage and in conjunction (1.0, 5.0, and 10 micro g/ml) with spermatozoa to evaluate competitive inhibition of fertilization and subsequent development. A (P < 0.01) higher number of bovine oocytes developed to the blastocyst stage after incubation with K, Ele and Ech at 1.0 micro g/ml, and was not different (P > 0.01) from IVF control. Fertilization was significantly reduced (P < 0.01) at all concentrations of K, Ele and Ech as compared to IVF control. No reduction (P > 0.05) was observed in EB (nonRGD) treated oocytes. These results support the involvement of a disintegrin-integrin interaction at fertilization in the bovine resulting in activation and subsequent development.

A novel approach to identify bovine sperm membrane proteins that interact with receptors on the vitelline membrane of bovine oocytes

“…Most integrins bind to an element that contains an aspartic acid residue (RGD, ECD, LDV, KGD, RTD, and KQAGD). Many integrins recognize the RGD sequence, which appears in ECM proteins and cell surface molecules (Ruoslahti and Pierschbacher, 1987), and has been implicated in fertilization (Campbell et al, 2000;Sessions et al, 2006;White et al, 2006). Interesting, 6 of the 19 proteins identified contain at least one of these known integrin ligand-binding sequences.…”

“…Additionally, cultured cells expressing interfering SRC kinase variants exhibited reduction in bacterial uptake. We have previously demonstrated the involvement of both FAK and Src kinases in fertilization (Pate et al, 2007a) as well as the presence of b1 integrins on bovine oocytes (Pate et al, 2007b) and the role of integrins in bovine sperm-oocyte interactions leading to oocyte activation and development (Campbell et al, 2000;Sessions et al, 2006;White et al, 2006). Invasin is a bacterial protein that mediates the uptake of bacterial cells into nonphagocytic eukaryotic cells.…”

Re: Is PAWP the ′real′ sperm factor?

“…This premature rejection of “contact/membrane addition hypothesis” of oocyte activation may have thwarted a potentially important line of investigation. 24 25 26 One should bear in mind that in the absence of sperm-oolema/oocyte cortex interactions, sperm and by extension sperm extract injection into the oocyte cytoplasm is not sufficient to trigger all aspects of oocyte activation and anti-polyspermy defense seen after natural fertilization. 27 28 …”