Ancient Neurohormone Discovery

In a revolutionary study by biologists at Queen Mary University of London, researchers have unveiled that a neurohormone responsible for appetite regulation in humans has roots stemming back more than half a billion years. This astonishing discovery, featured in the Proceedings of the National Academy of Sciences, underscores the evolutionary significance of a molecule known as bombesin, which is present not just in humans but also in starfish and their aquatic relatives.

The Role of Bombesin

Bombesin, a small peptide synthesized in the brain and gut, plays an essential role in signaling satiety and regulating our hunger patterns. Intriguingly, this neurohormone's history predates even the earliest vertebrates, highlighting a long-standing biological mechanism that governs food intake across various life forms. First isolated from the skin of the fire-bellied toad (Bombina bombina) in 1971, bombesin has been shown to decrease meal size and extend the intervals between eating sessions when injected into mammals.

Implications for Obesity Treatment

This ancient neurohormone comes into the spotlight once again as researchers explore its implications for treating obesity, particularly alongside modern weight-loss medications like Ozempic. Scientists are actively developing compounds that mimic the effects of bombesin to harness its appetite-suppressing power.

Evolutionary Research

Professor Maurice Elphick and his team embarked on a journey to uncover the evolutionary history of bombesin, collaborating with Dr. Olivier Mirabeau from the Institut Pasteur in Paris. Their analysis of the genomes of various invertebrates led them to discover the presence of bombesin-like genes in common starfish (Asterias rubens) and related echinoderms including sea urchins and sea cucumbers.

Experimental Findings

A bit like searching for a needle in a haystack, Professor Elphick remarked about the discovery. The team subsequently investigated the functions of the starfish variant of bombesin, dubbed ArBN, using advanced mass spectrometry techniques at the University of Warwick, which allowed them to determine its molecular structure and chemically synthesize it for further research.

Feeding Behavior Analysis

Dr. Weiling Huang, the lead researcher, studied how ArBN influences feeding behavior in starfish, creatures notorious for their unique method of digestion by everting their stomachs to envelop their prey, such as mussels and oysters. Her experiments revealed that introducing ArBN resulted in the contraction of the starfish stomach, signalling not only hunger cessation but also delaying the initiation of feeding.

Significance of the Findings

When ArBN was injected into starfish with their stomachs everted, the response was remarkable—it caused the stomach to retract back into the mouth, elaborated Dr. Huang. Additionally, those treated with ArBN took longer to enclose a mussel compared to their counterparts injected with water, indicating a tangible influence on feeding behavior.

Broader Implications

This groundbreaking discovery of the ancient functions of bombesin sheds new light on the evolutionary origins of feeding behavior across the animal kingdom, suggesting a shared lineage that extends back more than 500 million years to the common ancestor of starfish, humans, and other vertebrates.

Future Research and Environmental Impact

Beyond paving the way for innovative weight-loss treatments, the implications of this research hold broader potential. With climate change influencing the habitats of various species, including the migration of certain starfish into cooler waters where shellfish are harvested for human consumption, finding molecules that can inhibit feeding in these starfish could play a crucial role in managing ecological impacts.

Conclusion

As scientists continue to delve deeper into the mechanisms of appetite regulation, the discovery of bombesin’s ancient roots offers a profound understanding of how living organisms have adapted over millennia—a revelation with the potential to alter both health and environmental practices in the future.