In this work, we describe the molecular cloning and pharmacological properties of an acidic phospholipase A2 (PLA2) isolated from Bothrops pauloensis snake venom. This enzyme, denominated BpPLA2-TXI, was purified by four chromatographic steps and represents 2.4% of the total snake venom protein content. BpPLA2-TXI is a monomeric protein with a molecular mass of 13.6 kDa, as demonstrated by Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) analysis and its theoretical isoelectric point was 4.98. BpPLA2-TXI was catalytically active and showed some pharmacological effects such as inhibition of platelet aggregation induced by collagen or ADP and also induced edema and myotoxicity. BpPLA2-TXI displayed low cytotoxicity on TG-180 (CCRF S 180 II) and Ovarian Carcinoma (OVCAR-3), whereas no cytotoxicity was found in regard to MEF (Mouse Embryonic Fibroblast) and Sarcoma 180 (TIB-66). The N-terminal sequence of forty-eight amino acid residues was determined by Edman degradation. In addition, the complete primary structure of 122 amino acids was deduced by cDNA from the total RNA of the venom gland using specific primers, and it was significantly similar to other acidic D49 PLA2s. The phylogenetic analyses showed that BpPLA2-TXI forms a group with other acidic D49 PLA2s from the gender Bothrops, which are characterized by a catalytic activity associated with anti-platelet effects.

Toxoplasmosis affects a third of the global population and presents high incidence in tropical areas. Its great relevance in public health has led to a search for new therapeutic approaches. Herein, we report the antiparasitic effects of BnSP-7 toxin, a Lys49 phospholipase A2 (PLA2) homologue from Bothrops pauloensis snake venom, on Toxoplasma gondii. In an MTT assay, BnSP-7 presented significant cytotoxicity against host HeLa cells at higher doses (200 μg/mL to 50 μg/mL), whereas lower doses (25 μg/mL to 1.56 μg/mL) produced low cytotoxicity. Furthermore, the toxin showed no effect on T. gondii tachyzoite viability when evaluated by trypan blue exclusion, but decreased both adhesion and parasite proliferation when tachyzoites were treated before infection. We also measured cytokines in supernatants collected from HeLa cells infected with T. gondii tachyzoites previously treated with RPMI or BnSP-7, which revealed enhancement of only MIF and IL-6 cytokines levels in supernatants of HeLa cells after BnSP-7 treatment. Our results showed that the BnSP-7 PLA2 exerts an anti-Toxoplasma effect at a lower dose than that required to induce cytotoxicity in HeLa cells, and also modulates the immune response of host cells. In this sense, the anti-parasitic effect of BnSP-7 PLA2 demonstrated in the present study opens perspectives for use of this toxin as a tool for future studies on toxoplasmosis.

No abstract

No abstract

Snake venoms constitute a mixture of bioactive components that are involved not only in envenomation pathophysiology but also in the development of new drugs to treat many diseases. Different enzymatic and non-enzymatic proteins, such as phospholipases A2, hyaluronidases, L-amino acid oxidases, metalloproteinases, serine proteinases, lectins and disintegrins have been isolated and their functional and structural properties described in the literature. Many of these studies have also explored their medicinal potential focusing mainly on anticancer, antithrombotic and microbicide therapies. Bothrops pauloensis is a species found in Brazil, whose venom has been the focus of our studies in order to explore the biochemical and functional characteristics of their components. In this review, we have presented the main results of years of research on different toxins from B. pauloensis emphasizing their therapeutic potential. Studies concerning snake venom toxins to search for new therapeutic models open perspectives for new drug discovery.