Oxidative stress induced by crude venom from the jellyfish Pelagia noctiluca in neuronal-like differentiated SH-SY5Y cells
ABSTRACT Marine toxins are a suitable research model and their mechanism of action is intriguing and still under debate. Either a pore formation mechanism or oxidative stress phenomena may explain the damage induced by toxins. The effect of crude venom from isolated nematocysts of the jellyfish Pelagia noctiluca on neuronal-like cells derived from human neuroblastoma SH-SY5Y has been here studied. To prove the possible oxidative stress events, cell viability, assessed by MTT quantitative colorimetric assay, intracellular reactive oxygen species (ROS) quantified by the non-fluorescent probe H2DCF-DA and changes in mitochondrial transmembrane potential (ΔΨm) measured by the incorporation of a cationic fluorescent dye rhodamine-123 were verified on venom-treated cells (0.05-0.5μg/ml doses). A dose- and time-dependent reduction of all parameters was observed after venom treatment. NAC (N-acetyl-cysteine), antioxidant applied before crude venom application, significantly counteracted the decrease in cell viability and ROS production, while ΔΨm was only partially restored. The disruption of mitochondrial membrane by P. noctiluca crude venom may thus induce oxidative stress by inhibiting mitochondrial respiration and uncoupling oxidative phosphorylation, sensitizing mitochondria in SH-SY5H cells and facilitating membrane permeability. In sum, our findings suggest that P. noctiluca crude venom directly induces ΔΨm collapse with further generation of ROS and add novel information to the understanding of such toxins, still not completely clarified.
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ABSTRACT: Marine animals represent a good model for toxicological investigations, being a source of novel bioactive substances considered as a suitable research tool. Among stinging animals, Cnidarians possess specialized cells, termed nematocytes, containing an inverted tubule and toxins, synergistically responsible for mechanisms of defence and predation. Such compounds include proteins and secondary metabolites with toxic action. To elucidate the effects of Cnidarian venom upon cell targets, this short review reports on the biological activity of venom extracted from nematocysts of the jellyfish Pelagia noctiluca, whose "blooming" is well known in the Mediterranean Sea. The effects on erythrocytes and on cultured cells, from both mammals and invertebrates, along with in vivo studies, are here being considered. What is known about the biological activity of Pelagia noctiluca crude venom accounts for a notable effect at different levels, suggesting that cell damage may be due to a pore formation mechanism on cell membrane target leading to osmotic lysis, and /or to oxidative stress events. In this light, the study of venom activity may contribute to i) validate suitable biological assays for venom testing; ii) elucidate cell function features; iii) understand the pathophysiology of envenoming.Central Nervous System Agents in Medicinal Chemistry(Formerly Current Medicinal Chemistry - Central Nervous System Agents) 10/2014; DOI:10.2174/1871524914666141028150212
11/2014; 87(2). DOI:10.4081/jbr.2014.4813
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ABSTRACT: Scyphomedusae (Phylum Cnidaria, Class Scyphozoa) are perceived as a nuisance due to their sudden outbreaks that negatively affect human activities (particularly tourism and fisheries) mainly because of their stings. A brief review of the history of scyphozoan blooms in the Mediterranean and updated information available after 2010 point to an increase in scyphozoan outbreaks. Whilst the negative effects on public health, aquaculture, coastal industrial activities and fisheries operations are undeniable, the effects on the ecosystem are not well defined. We focus on the trophic interactions between scyphomedusae and fish, highlighting that the negative effects of scyphomedusae on fish stocks exerted through direct predation on early life stages of fish and competition for plankton are at present speculative. In favor of a positive effect of scyphomedusae on fish populations, the reports of predation upon scyphozoans are increasing, which suggests that predators may benefit from the availability of scyphozoans by shifting their diet toward jelly prey. Additionally, scyphomedusae may provide nursery habitats to early life stages of ecologically and economically important forage fishes and other organisms which shelter underneath their bells. Together with these ecosystem services, compounds extracted from scyphozoan tissues and venoms are having a variety of biomedical applications and are likely to contribute to treat a growing number of diseases, including cancer. Our analysis highlights that a re-evaluation of the balance between "positive" and "negative" effects of scyphomedusae on the ecosystem and human activities is needed and provides indications on potential directions for future studies.Central Nervous System Agents in Medicinal Chemistry(Formerly Current Medicinal Chemistry - Central Nervous System Agents) 03/2015;