A fungus discovered in the mouse stomach may hold a key to fungal evolution within the gastrointestinal tract, according to new research led by Weill Cornell Medicine investigators. The finding suggests that preclinical studies until now have overlooked a major influencer of mouse physiology.
Scientists recently have come to appreciate the importance, for human health and disease, of microbes—often called “commensals”—that naturally dwell in the gut. Bacterial commensals, for example, are known to have a big influence on human immunity; abnormal changes in these populations have been tied to cancers, inflammatory disorders and even depression. However, how gut fungal commensals affect immunity is less well understood, due in part to the lack of a good mouse model of fungal commensalism.
The new study, reported Nov. 27 in Nature, found that a yeast called Kazachstania pintolopesii, abundant in the stomach of wild mice, is exceptionally well adapted to mice and benefits them by boosting their immune protection against parasites, though it also enhances their vulnerability to some allergies.
“For years we’ve been looking for a true fungal commensal in mice, but fungal populations in lab mice, as identified by analyzing fungal DNA, tend to be transient and vary greatly from colony to colony,” said study senior author Dr. Iliyan Iliev, an associate professor of immunology in medicine, member of the Jill Roberts Institute for Research in Inflammatory Bowel Disease, and a faculty member in the Immunology & Microbial Pathogenesis graduate school program at Weill Cornell Medicine.
In 2019, a team led by