A Hidden Fungus: How a Microbe in Mice Could Change the Course of Medical Research
For years, scientists have known that microbes living in the gut – often called commensals – play a crucial role in human health and disease. These microscopic organisms can influence everything from immunity and digestion to mental health. But while bacterial commensals have been extensively researched, the fungal side of the story has remained largely untold.
Now, a groundbreaking study from Weill Cornell Medicine has revealed a common gut fungus in mice that could fundamentally alter our understanding of fungal commensalism and its impact on research. The discovery of Kazachstania pintolopesii, a yeast abundant in the stomach of wild mice, has opened a new chapter in the exploration of the complex relationship between microbes and mammals.
This tiny fungus, as researchers have found, is exceptionally well adapted to life inside mice. Not only does it benefit its host by bolstering their immune defense against parasites, but it also has a surprising downside – increasing their susceptibility to certain allergies. This intricate double-edged sword highlights the complex interplay between microbes and the immune system.
"We’ve been searching for a true fungal commensal in mice for years," explains Dr. Iliyan Iliev, a senior author of the study and associate professor of immunology in medicine at Weill Cornell Medicine. "Fungal populations in lab mice, when analyzed, tend to be transient and vary significantly from colony to colony." The discovery of K. pintolopesii provides a stable and reliable model for studying fungal commensalism in mice, potentially revolutionizing preclinical research.
The research team’s journey began with a serendipitous finding in 2019. A study led by Dr. Barbara Rehermann of the National Institutes of Health had shown that lab mice raised with gut microbes similar to wild mice mimicked human immune responses more accurately than traditional lab mice. Dr. Iliev’s team, participating in the study, detected significantly higher levels of fungal DNA in these "wildling" mice.
"This sparked our curiosity," Dr. Iliev recalls. "It was like a Sherlock Holmes story unfolding. We knew a dominant fungus must be lurking somewhere, so we set out to find it." New York City became their prime hunting ground, collaborating with pest-control companies and research institutions to collect samples. Their efforts ultimately led them to K. pintolopesii, a common resident of wild mice also frequently found, though undetected, in laboratory settings.
The implications are far-reaching. K. pintolopesii‘s presence, or lack thereof, could significantly influence the outcomes of various mouse studies, particularly those investigating allergies, parasite infections, cancer development, or any area involving type 2 or type 17 immune responses.
“We need to now consider the presence or absence of this fungus when designing and interpreting experimental results," emphasizes Dr. Yun Liao, a co-first author of the study and postdoctoral researcher in Dr. Iliev’s lab.
Dr. Iris Gao, another co-first author and former graduate student in the lab, adds, "Knowing about K. pintolopesii could completely change how we understand the experimental outcome. This fungus can significantly influence the research landscape."
This remarkable fungus boasts several fascinating characteristics. It can rapidly colonize the digestive tracts of lab mice, readily pass down to newborns, and evade the host’s antifungal defenses. Even more intriguingly, K. pintolopesii partially suppresses the growth of other fungal species, indicating a potential role in
What are the potential implications of using Kazachstania pintolopesii as a model organism for studying fungal commensalism in humans?
## A Hidden Fungus: How a Microbe in Mice Could Change the Course of Medical Research
**Host:** Welcome back to the show. Today, we’re delving into a fascinating new discovery that could change the way we understand the role of microbes in our bodies. Joining us is Dr. Iliyan Iliev, senior author of a groundbreaking study from Weill Cornell Medicine and associate professor of immunology in medicine. Dr. Iliev, thanks for being here.
**Dr. Iliev:** It’s my pleasure to be here.
**Host:** Your team has made a remarkable finding – a common gut fungus in mice that might hold the key to understanding fungal commensalism and its impact on medical research. Can you tell us more about this discovery?
**Dr. Iliev:** Of course. For years, scientists have focused on the bacterial side of the gut microbiome, but fungi play a crucial role too. We’ve been searching for a true fungal commensal in mice for a long time, one that consistently resides in their gut and provides clear benefits. [1]
**Host:** And you found it?
**Dr. Iliev:** Yes! It’s called Kazachstania pintolopesii, a yeast abundant in the stomachs of wild mice. It’s remarkably well adapted to life inside its host.
**Host:** What does it do?
**Dr. Iliev:** It’s a double-edged sword. _K. pintolopesii_ boosts the mice’s immune system, helping them fight off parasites. However, it also seems to increase their susceptibility to certain allergies.
**Host:** That’s fascinating and a bit surprising! Why is this finding so important for medical research?
**Dr. Iliev:** [1] Until now, fungal populations in lab mice have been inconsistent, making them unreliable for studying fungal commensalism. _K. pintolopesii_ provides a stable model, opening up new avenues for preclinical research. It could revolutionize how we study the complex interplay between fungi and the immune system in mammals.
**Host:** That’s huge! What are the next steps for your research?
**Dr. Iliev:** We’re eager to explore the mechanisms behind _K. pintolopesii_’s dual effects on the immune system. We also want to understand how this discovery might translate to human health.
**Host:** Dr. Iliev, thank you so much for sharing this exciting discovery with us today.
**Dr. Iliev:** Thank you for having me.
**Host:** For our listeners, this is just the beginning of a fascinating journey into the world of fungal commensalism and its potential impact on human health.
