Ion channels turn hedgehogs into superheroes

When we think of animals that can withstand a battle against venomous snakes, our minds might not immediately picture the small, spiny hedgehog. Known for their adorable appearance and quirky charm, hedgehogs are rarely, if ever, considered as the superheroes of the animal kingdom (except maybe the brave blue speedster, Sonic the Hedgehog, from the popular video game – not to be confused with the Sonic Hedgehog protein (SHH), a key signaling molecule regulating embryonic morphogenesis). At the first sign of danger, these little guys transform themselves into an original “Do Not Disturb” sign by quickly rolling into a perfect spiky ball to protect themselves.

Yet, beneath their cute exterior lies a remarkable trait that sets them apart: resistance to snake venom. Just like the mongoose, hedgehogs have been the subject of wonder and admiration for their ability to interact with snakes in ways that defy the ordinary. The question that intrigues many is: How can these small mammals resist the venomous bites of deadly snakes?

The mere mention of snakes like the king cobra or black mamba can send shivers down the spine of many. This fear, deeply ingrained in humans and many animals, stems from the potent toxins snakes use to immobilize or kill their prey. One type of snake toxin, called alpha-neurotoxins, binds to and inhibits nicotinic acetylcholine receptors (nAChRs) at the neuromuscular junctions, effectively halting the transmission of signals from nerves to muscles, leading to paralysis and respiratory failure.

Interestingly, hedgehogs, like mongooses, have developed mutations in their nAChRs that make them resistant to the alpha-neurotoxins found in snake venom. These mutations (W187R and F189L) alter their nAChRs in such a way that the alpha-neurotoxins can’t bind to these receptors, enabling hedgehogs to prey upon and survive bites from venomous snakes that would be fatal to other mammals. Indeed, hedgehogs’ diets can include a variety of insects, worms, snails, and even small snakes, showcasing their resilience and adaptability.

However, despite their capabilities, hedgehogs face challenges from habitat loss, road traffic, and pesticide use. Their presence in urban and suburban areas often brings them into conflict with human activities, highlighting the need for conservation efforts to ensure these remarkable creatures continue to thrive in their natural habitats.

Today, on Hedgehog Day, we celebrate these fascinating animals with their built-in venom defence. It’s pretty awesome how their ion channels turn them into tiny superheroes capable of fighting deadly snakes.