Scientists think they have discovered an antidote to the sting delivered by the box jellyfish Chironex fleckeri, which is considered to be one of the most venomous animals on Earth. The antidote blocks the symptoms of a box jellyfish sting if administered to the skin within 15 minutes of contact. It was shown to suppress tissue necrosis and pain in mice and to work on human cells outside the body.
Commonly known as the sea wasp, the box jellyfish has about 60 tentacles that can grow up to 10 feet (3 m) long. Each tentacle has millions of microscopic hooks filled with venom, a mixture of bioactive proteins that can cause potent hemolytic activity, cytotoxicity, membrane pore formation and inflammation.
A single sting to a human will cause necrosis of the skin, excruciating pain and, if the dose of venom is large enough, cardiac arrest and death within minutes. Scientists at the University of Sydney used the gene-editing tool CRISPR-Cas9 to identify how box jellyfish venom works. Using CRISPR genome editing techniques, scientists could quickly identify how the venom kills human cells.
Luckily, there was already a drug that could act on the pathway the venom uses to kill cells, and when scientists tried the drug as an antivenom on mice, they found it could block the tissue scarring and pain related to jellyfish stings.
The study authors took a vat of millions of human cells and knocked out a different human gene in each one. Then they added the box jellyfish venom and looked for the cells that survived. From the whole genome screening, they identified the factors that are required for the venom to work.
The jellyfish venom pathway identified in the study requires cholesterol, and since there are lots of drugs available that target cholesterol, scientists could try to block this pathway to see how it impacted venom activity. They took one of those drugs, which was known to be safe for human use, and used it against the venom, and it worked.
The scientists think the drug will stop the necrosis, skin scarring and the pain completely when applied to the skin. What they don’t know yet is if it will stop a heart attack. That will need more research.
The discovery is described in a paper published online April 30 in the journal Nature Communications.