For a long time, scientists have known there might be a connection between fungi and brain diseases like Alzheimer’s.
But how exactly this happens has remained unclear. A new study from Baylor College of Medicine and other research teams is now giving us more clues.
The researchers found that a common fungus called Candida albicans can enter the brain, trigger defense responses, and even create toxic protein pieces similar to those seen in Alzheimer’s disease.
Candida albicans is a type of fungus that can live in the human body. This new study shows how it breaks into the brain. The fungus makes enzymes called secreted aspartic proteases (Saps).
These enzymes damage the blood-brain barrier—the protective wall that normally keeps harmful substances out of the brain. Once that barrier is weakened, the fungus can get inside and start causing problems.
The researchers also studied how the brain tries to fight back. In healthy mice, the fungal infection goes away on its own within about 10 days. This is because brain immune cells, called microglia, jump into action. The study found two main ways these cells respond to Candida albicans.
First, the Saps that help the fungus get into the brain also break down a protein in the brain called amyloid precursor protein.
This creates toxic pieces called amyloid beta-like peptides (Ab-like peptides), which are known to be linked to Alzheimer’s. These peptides activate microglia through a receptor called Toll-like receptor 4. This helps reduce the amount of fungus, but doesn’t fully clear it.
Second, the fungus makes another protein called candidalysin. This protein connects to a different receptor on microglia called CD11b. This second response is critical—without it, the brain can’t fully remove the fungus. Disrupting this pathway makes it harder to clear the infection.
So, why does this matter for Alzheimer’s disease? The current theory is that Alzheimer’s is caused by toxic amyloid beta peptides that build up in the brain.
Until now, these peptides were thought to come only from the brain’s own enzymes. But this study shows that Candida albicans can also create the same toxic peptides, suggesting another source of the damage.
Candida albicans has been found in the brains of people with Alzheimer’s and other brain disorders. This raises the possibility that infections from this common fungus might play a role in starting or worsening the disease.
While this research was done in animals, it offers a new idea about what could cause Alzheimer’s. If future studies confirm these results in humans, it could open the door to new treatments that focus on controlling fungal infections or blocking the harmful enzymes they produce.
This study helps us understand more about how Alzheimer’s might develop and shows the importance of continuing research into how infections affect the brain.
If you’re concerned about Alzheimer’s, other studies have looked at possible causes, diets that may help prevent it, and lifestyle changes that could reduce your risk. Researchers are also testing new non-drug treatments that may help keep your brain healthy as you age.
This study was published in the journal Cell Reports.
If you care about Alzheimer’s disease, please read studies about root cause of Alzheimer’s disease and new treatment and Scientists find the link between eye disease glaucoma and Alzheimer’s disease.
For more health information, please read studies about new way to treat Alzheimer’s disease and Fluctuating cholesterol and triglyceride levels are linked to Alzheimer’s disease.
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