Effects of MLO crude venom, PLA2 and metalloproteinases enzymes on cardiac cells

Abstract

Macrovipera lebetina obtusa (MLO) snakes presented by several sub-species, which are characterized by a very specific combination of components. Along with common enzymes characteristic of Vipera species, MLO venom contains unique components specific for “obtusa” sub-species, such as disintegrin obtustatin. MLO venom contents metalloproteinases, phospholipase A2, serine proteases, L-alfa amino acid oxidase, few kinds of disintegrins and some other active agents. The cluster of MLO venom components, such as metalloproteinases, obtustatin, C-type lectins and few others are known as cell adhesion inhibition molecules, which are breaking up integrins and cadherins or bind to them. Therefore, the adhesion affecting properties of MLO venom and its action on cell binding in tissue culture is of great interest. We studied effect of venom of MLO living in Armenia on adhesion and metabolic activity of myocardial cells [cardiomyocytes (CM) and cardiac fibroblasts (CF)] and identification of major effector components of MLO venom.

Attachment properties of both CM and CF were affected by MLO venom in a dose-dependent manner. Time exposure also has an effect on CMs and CFs attachment to the substrate and to cell-to-cell contact. Longer exposures times result in higher detachment even at the same MLO venom concentrations. Interestingly, both cell types demonstrated increase in metabolic activity upon exposure to non-lethal doses of crude venom.

Analysis of individual components of MLO venom resulted improved adhesion of both CM and CF upon inhibition of metalloproteinases by EDTA-Na2 chelating agent or complete block of PLA2 enzyme by bromophenacyl bromide. These results indicate that the aggressive detaching effect of MLO venom is delivered not by an individual component of the venom, but rather is a combinatorial effect of several active ingredients.