Danio rerio as an alternative vertebrate model for jellyfish venom study: The toxinological aspects of Nemopilema nomurai venom

Identification of New Angiotensin-Converting Enzyme Inhibitory Peptides Isolated from the Hydrolysate of the Venom of Nemopilema nomurai Jellyfish

Recently, jellyfish venom has gained attention as a promising reservoir of pharmacologically active compounds, with potential applications in new drug development. In this investigation, novel peptides, isolated from the hydrolysates of Nemopilema nomurai jellyfish venom (NnV), demonstrate potent inhibitory activities against angiotensin-converting enzyme (ACE). Proteolytic enzymes-specifically, papain and protamex-were utilized for the hydrolysis under optimized enzymatic conditions, determined by assessing the degree of hydrolysis through the ninhydrin test. Comparative analyses revealed that papain treatment exhibited a notably higher degree of NnV hydrolysis compared to protamex treatment. ACE inhibitory activity was quantified using ACE kit-WST, indicating a substantial inhibitory effect of 76.31% for the papain-digested NnV crude hydrolysate, which was validated by captopril as a positive control. The separation of the NnV-hydrolysate using DEAE sepharose weak-anion-exchange chromatography revealed nine peaks under a 0-1 M NaCl stepwise gradient, with peak no. 3 displaying the highest ACE inhibition of 96%. The further purification of peak no. 3 through ODS-C18 column reverse-phase high-performance liquid chromatography resulted in five sub-peaks (3.1, 3.2, 3.3, 3.4, and 3.5), among which 3.2 exhibited the most significant inhibitory activity of 95.74%. The subsequent analysis of the active peak (3.2) using MALDI-TOF/MS identified two peptides with distinct molecular weights of 896.48 and 1227.651. The peptide sequence determined by MS/MS analysis revealed them as IVGRPLANG and IGDEPRHQYL. The docking studies of the two ACE-inhibitory peptides for ACE molecule demonstrated a binding affinity of -51.4 ± 2.5 and -62.3 ± 3.3 using the HADDOCK scoring function.

Zebrafish as Versatile Model for Assessing Animal Venoms and Toxins: Current Applications and Future Prospects

Animal venoms and toxins hold promise as sources of novel drug candidates, therapeutic agents, and biomolecules. To fully harness their potential, it is crucial to develop reliable testing methods that provide a comprehensive understanding of their effects and mechanisms of action. However, traditional rodent assays encounter difficulties in mimicking venom-induced effects in human due to the impractical venom dosage levels. The search for reliable testing methods has led to the emergence of zebrafish (Danio rerio) as a versatile model organism for evaluating animal venoms and toxins. Zebrafish possess genetic similarities to humans, rapid development, transparency, and amenability to high-throughput assays, making it ideal for assessing the effects of animal venoms and toxins. This review highlights unique attributes of zebrafish and explores their applications in studying venom- and toxin-induced effects from various species, including snakes, jellyfish, cuttlefish, anemones, spiders, and cone snails. Through zebrafish-based research, intricate physiological responses, developmental alterations, and potential therapeutic interventions induced by venoms are revealed. Novel techniques such as CRISPR/Cas9 gene editing, optogenetics, and high-throughput screening hold great promise for advancing venom research. As zebrafish-based insights converge with findings from other models, the comprehensive understanding of venom-induced effects continues to expand, guiding the development of targeted interventions and promoting both scientific knowledge and practical applications.

Exploring the Efficacy of Hydroxybenzoic Acid Derivatives in Mitigating Jellyfish Toxin-Induced Skin Damage: Insights into Protective and Reparative Mechanisms

The escalation of jellyfish stings has drawn attention to severe skin reactions, underscoring the necessity for novel treatments. This investigation assesses the potential of hydroxybenzoic acid derivatives, specifically protocatechuic acid (PCA) and gentisic acid (DHB), for alleviating Nemopilema nomurai Nematocyst Venom (NnNV)-induced injuries. By employing an in vivo mouse model, the study delves into the therapeutic efficacy of these compounds. Through a combination of ELISA and Western blot analyses, histological examinations, and molecular assays, the study scrutinizes the inflammatory response, assesses skin damage and repair mechanisms, and investigates the compounds' ability to counteract venom effects. Our findings indicate that PCA and DHB significantly mitigate inflammation by modulating critical cytokines and pathways, altering collagen ratios through topical application, and enhancing VEGF and bFGF levels. Furthermore, both compounds demonstrate potential in neutralizing NnNV toxicity by inhibiting metalloproteinases and phospholipase-A2, showcasing the viability of small-molecule compounds in managing toxin-induced injuries.

Identification of cardiorespiratory toxic components of Nemopilema nomurai jellyfish venom using sequential chromatography methods

Jellyfish stings pose a significant threat to humans in coastal areas worldwide, with venomous jellyfish species stinging millions of individuals annually. Nemopilema nomurai is one of the largest jellyfish species, with numerous tentacles rich in nematocysts. N. nomurai venom (NnV) is a complex mixture of proteins, peptides, and small molecules that serve as both prey-capture and defense mechanisms. Yet, the molecular identity of its cardiorespiratory and neuronal toxic components of NnV has not been clearly identified yet. Here, we isolated a cardiotoxic fraction, NnTP (Nemopilema nomurai toxic peak), from NnV using chromatographic methods. In the zebrafish model, NnTP exhibited strong cardiorespiratory and moderate neurotoxic effects. LC-MS/MS analysis identified 23 toxin homologs, including toxic proteinases, ion channel toxins, and neurotoxins. The toxins demonstrated a synergistic effect on the zebrafish, leading to altered swimming behavior, hemorrhage in the cardiorespiratory region, and histopathological changes in organs such as the heart, gill, and brain. These findings provide valuable insights into the mechanisms underlying the cardiorespiratory and neurotoxic effects of NnV, which could be useful in developing therapeutic strategies for venomous jellyfish stings.

Cloning of Metalloproteinase 17 Genes from Oriental Giant Jellyfish Nemopilema nomurai (Scyphozoa: Rhizostomeae)

We previously demonstrated that Nemopilema nomurai jellyfish venom metalloproteinases (JVMPs) play a key role in the toxicities induced by N. nomurai venom (NnV), including dermotoxicity, cytotoxicity, and lethality. In this study, we identified two full-length JVMP cDNA and genomic DNA sequences: JVMP17-1 and JVMP17-2. The full-length cDNA of JVMP17-1 and 17-2 contains 1614 and 1578 nucleotides (nt) that encode 536 and 525 amino acids, respectively. Putative peptidoglycan (PG) binding, zinc-dependent metalloproteinase, and hemopexin domains were identified. BLAST analysis of JVMP17-1 showed 42, 41, 37, and 37% identity with Hydra vulgaris, Acropora digitifera, Megachile rotundata, and Apis mellifera venom metalloproteinases, respectively. JVMP17-2 shared 38 and 36% identity with H. vulgaris and A. digitifera, respectively. Alignment results of JVMP17-1 and 17-2 with other metalloproteinases suggest that the PG domain, the tissue inhibitor of metalloproteinase (TIMP)-binding surfaces, active sites, and metal (ion)-binding sites are highly conserved. The present study reports the gene cloning of metalloproteinase enzymes from jellyfish species for the first time. We hope these results can expand our knowledge of metalloproteinase components and their roles in the pathogenesis of jellyfish envenomation.

Revealing the toxicity of lopinavir- and ritonavir-containing water and wastewater treated by photo-induced processes to Danio rerio and Allivibrio fischeri

In coronavirus disease 2019 (COVID-19), among many protocols, lopinavir and ritonavir in individual or combined forms with other drugs have been used, causing an increase in the concentration of antiviral drugs in the wastewater and hospital effluents. In conventional wastewater treatment plants, the removal efficiency of various antiviral drugs is estimated to be low (<20%). The high values of predicted no-effect concentration (PNEC) for lopinavir and ritonavir (in ng∙L^-1) reveal their high chronic toxicity to aquatic organisms. This indicates that lopinavir and ritonavir are current priority antiviral drugs that need to be thoroughly monitored and effectively removed from any water and wastewater samples. In this study, we attempt to explore the impacts of two photo-induced processes (photolysis and photocatalysis) on the toxicity of treated water and wastewater samples containing lopinavir and ritonavir to zebrafish (Danio rerio) and marine bacteria (Allivibrio fischeri). The obtained results reveal that traces of lopinavir in water under photo-induced processes may cause severe problems for Danio rerio, including pericardial edema and shortening of the tail, affecting its behavior, and for Allivibrio fischeri as a result of the oxygen-depleted environment, inflammation, and oxidative stress. Hence, lopinavir must be removed from water and wastewater before being in contact with light. In contrast, the photo-induced processes of ritonavir-containing water and wastewater reduce the toxicity significantly. This shows that even if the physicochemical parameters of water and wastewater are within the standard requirements/limits, the presence of traces of antiviral drugs and their intermediates can affect the survival and behavior of Danio rerio and Allivibrio fischeri. Therefore, the photo-induced processes and additional treatment of water and wastewater containing ritonavir can minimize its toxic effect.

Dataset of Swimming behavioral alterations in Danio rerio by Nemopilema nomurai jellyfish venom

This article reports data associated with Prakash et al. [1]. Nemopilema nomurai jellyfish venom (NnV) can lead to neurotoxicity in zebrafish (Danio rerio) model. In the present study, zebrafish were treated with NnV by intraperitoneal injection and the swimming behavior of each fish was evaluated using a score scale. The dose of NnV in each treatment group was based on the protein concentration of NnV. Swimming is the main locomotory movements in the fishes. NnV modulated the swimming behavior of Danio rerio in a dose-dependent manner. In this article provided data are directly related to the previously published research article – “Danio rerio as an alternative vertebrate model for jellyfish venom study: the toxinological aspects of Nemopilema nomurai venom” [1] where the downregulation of acetylcholinesterase activity as well as histopathological alterations were observed from the brain of Danio rerio treated with NnV. Here we provide datasets, including mortality rate table, swimming behavior graph, and videos of zebrafish after NnV envenomation.