How this fungus feeds on brains? 🧠

A recent study sheds light on an intriguing interaction between a fungus and the immune system of fruit flies, leading to dramatic consequences for their brains. This discovery opens up perspectives on the mechanisms by which fungal infections could influence the human brain.


Researchers have discovered that the fungus Beauveria bassiana triggers an immune response in fruit flies, causing the destruction of neurons and glial cells in the brain. This dysregulated immune response leads to neurodegeneration, with more than half of the infected flies dying within seven days, compared to a survival rate of nearly 50 days for non-infected flies.

The team from the University of Birmingham exposed fruit flies to B. bassiana, observing that the fungus crosses the blood-brain barrier within three days. This invasion triggers an immune response via Toll receptors, which, instead of protecting, activates a pathway leading to cell death in the brain.


The key player in this process is a molecule called Sarm, nicknamed the 'master of destruction'. Sarm suppresses the immune response and causes brain cell death, allowing the fungus to feed on brain cells. This immune evasion strategy illustrates an evolutionary arms race between hosts and pathogens.

Alicia Hidalgo, a professor of neurogenetics, explains that this study reveals how fungi have evolved to deceive the immune system and reach the brain. Although B. bassiana does not affect humans, this research suggests that other fungal infections could influence the human brain in a similar manner.

Dr. Deepanshu Singh, co-author of the study, emphasizes the importance of these findings for understanding the evolution of defense mechanisms and pathogen evasion strategies. This study, published in PLOS Biology, offers new insights into host-pathogen interactions and their potential implications for human health.

How do fungi manipulate the immune system?

Fungi like Beauveria bassiana have developed sophisticated strategies to manipulate the immune system of their hosts. By activating Toll receptors, they trigger an immune response that, instead of eliminating them, leads to the destruction of brain cells.

This manipulation relies on the production of specific molecules, such as Sarm, which suppress the immune response and induce cell death. This allows the fungus to bypass the host's defenses and spread within the brain.

This interaction illustrates an evolutionary arms race, where pathogens continuously develop new strategies to evade the immune defenses of their hosts. Understanding these mechanisms is crucial for developing new therapeutic approaches against fungal infections.

What is the blood-brain barrier and why is it important?

The blood-brain barrier is a protective structure that prevents harmful substances and pathogens from entering the brain. It is essential for maintaining brain homeostasis and protecting neurons from damage.


However, some pathogens, like Beauveria bassiana, have developed mechanisms to cross this barrier. Once inside, they can manipulate the immune system and cause brain damage.

The ability of fungi to cross the blood-brain barrier underscores the importance of understanding how these pathogens interact with the host's defense systems. This could have implications for the prevention and treatment of fungal infections affecting the brain.