The nematocysts venom of Chrysaora helvola Brandt leads to apoptosis-like cell death accompanied by uncoupling of oxidative phosphorylation

Peripheral Pain Modulation of Chrysaora pacifica Jellyfish Venom Requires Both Ca2+ Influx and TRPA1 Channel Activation in Rats

The venom of jellyfish triggers severe dermal pain along with inflammation and tissue necrosis, and occasionally, induces internal organ dysfunction. However, the basic mechanisms underlying its cytotoxic effects are still unknown. Here, we report one of the mechanisms involved in peripheral pain modulation associated with inflammatory and neurotoxic oxidative signaling in rats using the venom of jellyfish, Chrysaora pacifica (CpV). This jellyfish is identified by brown tentacles carrying nematocysts filled with cytotoxic venom that induces severe pain, pruritus, tentacle marks, and blisters. The subcutaneous injection of CpV into rat forepaws in behavioral tests triggered nociceptive response with a decreased threshold for mechanical pain perception. These responses lasted up to 48 h and were completely blocked by verapamil and TTA-P2, T-type Ca²⁺ channel blockers, or HC030031, a transient receptor potential cation ankyrin 1 (TRPA1) channel blocker, while another Ca²⁺ channel blocker, nimodipine, was ineffective. Also, treatment with Ca²⁺ chelators (EGTA and BaptaAM) significantly alleviated the CpV-induced pain response. These results indicate that CpV-induced pain modulation may require both Ca²⁺ influx through the T-type Ca²⁺ channels and activation of TRPA1 channels. Furthermore, CpV induced Ca²⁺-mediated oxidative neurotoxicity in the dorsal root ganglion (DRG) and cortical neurons dissociated from rats, resulting in decreased neuronal viability and increased intracellular levels of ROS. Taken together, CpV may activate Ca²⁺-mediated oxidative signaling to produce excessive ROS acting as an endogenous agonist of TRPA1 channels in the peripheral terminals of the primary afferent neurons, resulting in persistent inflammatory pain. These findings provide strong evidence supporting the therapeutic effectiveness of blocking oxidative signaling against pain and cytotoxicity induced by jellyfish venom.

Inhibitory Effect of Metalloproteinase Inhibitors on Skin Cell Inflammation Induced by Jellyfish Nemopilema nomurai Nematocyst Venom

Jellyfish envenomations result in extensive dermatological symptoms, clinically named as jellyfish dermatitis, which can seriously affect the daily activities and physical health of people. Inflammatory response accompanies the whole process of jellyfish dermatitis and the complexity of jellyfish venom components makes it difficult to treat jellyfish dermatitis symptoms effectively. Moreover, inhibiting inflammation is essential for the treatment of jellyfish stings and exploring the main components of jellyfish venom that cause inflammation is an urgent research area. In this study, the inhibitory effects of matrix metalloproteinase (MMP) inhibitors for venom-induced inflammation were explored at a cellular level. The expression of the three inflammatory factors, IL-6, TNF-α and MCP-1 in two skin cell lines, human keratinocyte cells (HaCaT) and human embryonic skin fibroblasts cells (CCC-ESF-1), at the cellular level, after treatment with the inhibitors of jellyfish Nemopilema nomurai (N. nomurai) nematocyst venom (NnNV-I), were determined. The results showed that inhibitors of MMP can significantly reduce the toxic effects of jellyfish Nemopilema nomurai nematocyst venom (NnNV) to skin cells. The expression levels of the three inflammatory factors IL-6, MCP-1, and TNF-α in the cells were also significantly decreased, indicating that MMPs in jellyfish venom are probably vital factors leading to jellyfish dermatitis. This study is beneficial in the prevention and treatment of jellyfish stings.

Activation of Na+/H+ exchanger other than formation of transmembrane pore underlies the cytotoxicity of nematocyst venom from Chrysaora helvola Brandt jellyfish

We previously reported unexpected apoptosis-like cell death induced by nematocyst venom (NV) from Chrysaora helvola Brandt (C. helvola) jellyfish. To assess whether the pore formation mechanism underlay the action of NV, the change in cell membrane permeability was studied in both chicken erythrocytes and human CNE-2 cells. Initially, paradoxical results were derived from osmoprotectant protection assays. Polyethylene glycol (PEG)₂₀₀₀, which completely inhibited the NV induced hemolysis, failed to protect CNE-2 cells. Detailed experiments showed that PEG protection from hemolysis is concentration dependent and indicated caution when estimating the pore size formed by NV with the osmotic protection method. NV-treated CNE-2 cells remained impermeable to dyes with various molecular weights (MWs) (622.6-40,000 Da). Furthermore, membrane depolarization and selective permeability to Na⁺ other than K⁺ were induced in CNE-2 cells. No oxidative damage to the cell membrane was detected. Amiloride, an inhibitor of Na⁺/H⁺ exchanger (NHE), substantially protected both CNE-2 cells and erythrocytes from NV. Combined with the previously reported increase in intracellular pH, we supposed that NV activated plasma membrane NHE without forming transmembrane pores. Interestingly, glutathione (GSH) showed significant protection to CNE-2 cells while potentiating the hemolytic power of NV. This finding may suggest a key role of reactive oxygen species (ROS) in the cytotoxicity of NV. To the best of our knowledge, this is the first report that a hemolytic jellyfish venom acts through NHE in a manner other than compromising membrane integrity. The current work provides new insight into the arsenal of toxic jellyfishes.

Immunotherapy of Dual-Function Vector with Both Immunostimulatory and B-Cell Lymphoma 2 (Bcl-2)-Silencing Effects on Gastric Carcinoma

BACKGROUND Tumorigenesis is a kind of pathology marked by infinite proliferation and restrained apoptosis compared with normal cells. The abnormal expression of some proto-oncogenes and apoptosis inhibition are essential for tumor growth, which has been confirmed by molecular biologic and immunologic studies. The hypofunction of the host immune system also drives the development and metastasis of malignant tumors. Bcl-2, which has a critical role in regulating apoptosis, is overexpressed in several cancers. MATERIAL AND METHODS In this study, we constructed a dual-function small hairpin RNA (shRNA) vector containing an Bcl-2-silencing shRNA and a TLR7-stimulating ssRNA and examined it effect on tumor cell growth and proliferation. RESULTS Stimulation with this bi-functional vector in vitro promoted significant apoptosis of MFC cells by regulating the expression of apoptosis-related proteins and induced secretion of type I IFNs. Most importantly, this bi-functional vector more effectively inhibited subcutaneous MFC cell growth than did single shRNA and ssRNA treatment in vivo. Natural killer (NK) and CD4+ T cells were required for effective tumor suppression, and TLR7 was shown to play a helper role in the activation of NK cells and CD4+ T cells, possibly by regulating the expression of receptors or secretion of cytokines. CONCLUSIONS This bi-functional vector that contained ssRNA and shRNA may represent a promising approach for tumor therapy.

Persian Gulf Jellyfish (Cassiopea andromeda) Venom Fractions Induce Selective Injury and Cytochrome C Release in Mitochondria Obtained from Breast Adenocarcinoma Patients

Objective:

This study was conducted to investigate whether fractions of jellyfish Cassiope andromeda venom, could selectively induce toxicity on mitochondria isolated from cancer tissue of patients with breast adenocarcinomas.

Methods:

Firstly, we extracted two fractions, (f1 and f2) from crude jellyfish venom by gel filtration on Sephadex G-200. Then different dilutions of these extracted fractions were applied to mitochondria isolated from human breast tumoral- and extra-tumoral tissues. Parameters of mitochondrial toxicity including generation of reactive oxygen species (ROS), mitochondrial membrane potential (MMP) collapse, swelling, cytochrome c release, activation of caspase3 and apoptosis were then assayed.

Result:

Our results demonstrate that fraction 2 of Cassiopea andromeda crude venom significantly (P<0.05) decreased mitochondrial succinate dehydrogenase activity, increased mitochondrial ROS production, induced mitochondrial swelling, MMP collapse and cytochrome c release, activated caspase3 and induced apoptosis only in tumoral mitochondria, and not in mitochondria obtained from extra-tumoral tissue (P<0.05).

Conclusion:

In conclusion this study suggested that fraction 2 of Cassiopea andromeda crude venom selectively induces ROS mediated cytotoxicity by directly targeting mitochondria isolated from human breast tumor tissue.