Yucatan cave crustaceans may hold key to treating epilepsy

The journal BMC Biology reports that toxins produced by the crustacean Xibalbanus tulumensis, which lives in water-flooded caves of the Yucatan Peninsula, may be used to treat neurological diseases.

Many animals produce venom, which consists of toxins, and it is typically used for self-defense or hunting. These toxins disrupt various physiological processes, which makes them particularly interesting from a pharmacological perspective.

Until now, the most understood venoms were those of certain groups of animals, such as snakes, spiders, or scorpions. However, much less is known about toxins found in marine animals, creating significant opportunities for discoveries.

Just a few years ago, venomous crustaceans belonging to the group Remipedia living in water-flooded caves were discovered.

Dr. Björn von Reumont was the first, in 2014, to describe Remipedia's ability to produce venom. He is currently continuing studies on this phenomenon with an interdisciplinary team of researchers from Goethe University in Frankfurt. The team collaborates with the Fraunhofer Institute for Translational Medicine (ITMP) and research centers in Leuven, Cologne, Berlin, and Munich.

As a result of the research, scientists characterized a group of toxins produced by the remipede Xibalbanus tulumensis, which resembles a centipede. The name of this crustacean comes from "Xibalba," referring to the mythical underworld of the dead, whose entrances are said to be located in cave systems on the Mexican Yucatan Peninsula.

The animal mentioned injects venom into its prey through a special venom gland. The toxin's composition is exceptionally diverse, and the latest studies have revealed the presence of a new type of peptide, named by scientists as Xibalba.

Some xibalbins contain unique structural elements similar to those from other venomous animals, including spiders. These peptides have a knot-like structure, making them resistant to enzymes, high temperatures, and extreme pH values.

Such knot-like structures often operate as neurotoxins, interacting with ion channels and paralyzing the victim. Research has shown that numerous xibalbins, particularly Xib1, Xib2, and Xib13, can block potassium channels in mammalian cells.

This inhibition is greatly important when it comes to developing drugs ... range of neurological diseases, including epilepsy, explained Dr. Björn von Reumont.

Moreover, Xib1 and Xib13 can block voltage-gated sodium channels, such as those found in nerve or heart muscle cells.

Research also revealed that in higher mammalian sensory neurons, these peptides can activate two key proteins — PKA-II and ERK1/2 kinases. These processes suggest that peptides play a role in the pain sensitization mechanism, thus opening new perspectives in treating pain conditions.

Finding suitable candidates and comprehensively characterizing their effects, thus laying the foundation for safe and effective drugs, is currently only possible in a large interdisciplinary team, as in the case of the research indicated by von Reumont.

Researchers face many challenges. Their work is hampered by the fact that the habitat of the remipedes is seriously threatened by the construction of the Tren Maya intercity railway, which cuts through the Yucatan Peninsula.

— Cenotes (natural limestone wells filled with water) are an extremely sensitive ecosystem, emphasized von Reumont, who, as an experienced cave diver, personally collected remipedes during an expedition to the Yucatan. — Our research underscores the importance of biodiversity protection not only for its ecological significance but also for its potential substances that may be crucial to us humans, he noted.