# Gut bacteria make N-MNA, an NAD precursor that boosted intestinal stem cell renewal in flies and mice

- Published: 2026-11-07 21:10 UTC
- Section: Life & Health › Biology & biochemistry
- Tags: N-methylnicotinamide, NAD precursor, commensal bacteria, probiotic species, Preiss-Handler pathway, SIRT1, intestinal stem cell regeneration, gut dysbiosis, epithelial repair
- URL: https://realtech.media/news/rt-27eceec4169a7fd78b8d5e16_gut_bacteria_make/

**Commensal and probiotic bacteria produce N-methylnicotinamide, which cells convert to NAD+; in fruit flies and mice it promoted gut epithelial repair.**

![Gut bacteria make N-MNA, an NAD precursor that boosted intestinal stem cell renewal in flies and mice](https://realtech.media/media/2026/11/a75ab6e403ba835f.jpg)
*Dr William Ju, University of Toronto, Wikimedia Commons, CC BY 4.0*

Researchers report in Science Advances that certain commensal bacteria, including specific probiotic species, produce (amide-)N-methylnicotinamide (N-MNA) [1]. It is a structural isomer of methylnicotinamide, a nicotinamide degradation metabolite. NAD is a cellular coenzyme whose decline is associated with chronic and inflammatory diseases. Patients with gut dysbiosis and inflammation showed reduced N-MNA in stool [1].

Stable isotope tracing showed that N-MNA is rapidly taken up and incorporated into NAD redox reactions by intestinal epithelial cells and other cell types of fruit fly, mouse and human [1]. Genetic and pharmacological analyses suggest that N-MNA is converted to NAD+ via the Preiss-Handler pathway, independent of the salvage pathway [1].

In Drosophila, the authors ablated or overexpressed SIRT1, an NAD-consuming enzyme, in specific cell types. In mice, they traced the lineage of intestinal stem cells. These experiments showed that systemic N-MNA supplementation promotes intestinal stem cell regeneration and gut epithelial repair [1].

Compared with known NAD precursors, N-MNA brings a methyl group into host cells. The authors describe it as a class of microbe-derived NAD precursor that stimulates the regenerative capacity of tissue [1].

## Sources

1. [Science Advances](https://doi.org/10.1126/sciadv.aef2882)

---

Source: RealTech, realtech.media — https://realtech.media/news/rt-27eceec4169a7fd78b8d5e16_gut_bacteria_make/