The Amazing Role of a Gut Hormone in Maintaining a Healthy Gut Microbiome

Wednesday - January 24 2024, 08:24 UTC - 10 months ago

Peptide YY, a hormone that controls appetite, was found to also serve as a potent antifungal agent that selectively allows beneficial yeast forms to thrive while preventing harmful fungal overgrowth, thereby maintaining a healthy gut microbiome. This has important implications for treating gut fungal infections and sheds light on the role of specialized immune cells called Paneth cells in maintaining gut health.

Peptide YY, or PYY for short, is a hormone produced by specialized cells in the gut that was previously thought to only control appetite. However, new research from the University of Chicago has revealed an exciting new function of this hormone - it also plays a crucial role in maintaining a healthy balance of fungi in the digestive system. This study, published in the journal Science, sheds light on the importance of PYY in the delicate ecosystem of the gut microbiome.

The research team, led by Eugene B. Chang, MD, found that PYY produced by Paneth cells - crucial immune defenders in the gut - serves as a potent antimicrobial agent against a specific type of fungus, Candida albicans. This type of yeast is normally found in small amounts on the skin, in the mouth, and in the intestines. Its basic, commensal form is harmless, but when given the opportunity, it can transform into a more virulent form that can cause a variety of infections including thrush, vaginal yeast infections, and more serious systemic infections.

But how does PYY accomplish this feat? The researchers discovered that PYY selectively allows the beneficial yeast forms to thrive while preventing harmful fungal overgrowth. This means that when present in the body, PYY keeps the fungus in check and prevents it from becoming pathogenic. This is in stark contrast with normal medicine, which focuses on killing the fungus instead of just keeping it in its harmless form. This groundbreaking research has revealed a new potential avenue for treating and preventing gut fungal infections.

Interestingly, the discovery of PYY's antifungal properties was coincidental. While studying PYY's role in appetite control, a team member noticed that it was also present in Paneth cells, which play a crucial role in protecting against bacterial infections. This led to further investigation and the discovery of PYY's potent antifungal properties. Through computer searches, the team also found that a peptide closely resembling PYY - found on the skin of the African clawed frog - served as an effective antibacterial and antifungal agent. Armed with this knowledge, the researchers tested PYY against a variety of bacteria and found that it was only effective against the Candida species.

As further evidence of PYY's critical role in maintaining gut health, the team studied mice that lacked Paneth cells. When given antibiotics, these mice had significantly more Candida in their guts than control mice. However, when they were injected with PYY, they were protected from developing Candida infections. In addition to its antifungal properties, PYY was also found to be ineffective against common bacteria such as E. coli, Staphylococcus aureus, and Klebsiella pneumoniae.

This research has important implications for understanding and treating gut fungal infections in the future. The discovery of PYY's role in regulating the balance of fungi in the gut microbiome sheds light on a previously unknown aspect of gut health. It also highlights the importance of Paneth cells in not only protecting against bacterial infections, but also in regulating the delicate balance of fungi in the gut microbiome.