The finding matters because gestational diabetes affects a substantial share of pregnancies worldwide and raises risks for both mother and child, including future type 2 diabetes. Previous observational work had already hinted that pregnant women who develop the condition tend to have lower levels of butyrate in their circulation. What remained unclear was whether this deficiency was merely a byproduct of the disease or a genuine driver of it, and if the latter, through which molecular route butyrate might act. The new study set out to answer both questions with a combination of human data, animal experiments and mechanistic work at the level of chromatin.

The clinical arm of the study was a nested case-control analysis that measured serum butyrate and active GLP-1, the glucagon-like peptide-1 hormone released by intestinal cells after meals to stimulate insulin secretion, in pregnant women. The results were striking in their consistency: women who went on to develop gestational diabetes had significantly lower levels of both butyrate and active GLP-1, and this difference was detectable not only in mid-pregnancy, when the condition typically manifests, but already in early pregnancy. That early timing is important, because it suggests that a depleted butyrate-GLP-1 axis precedes the onset of disease rather than simply following from it, raising the possibility of prediction and even prevention.

To test causality, the team turned to a mouse model of gestational diabetes induced by a high-fat diet combined with antibiotics, a regimen that disrupts the gut microbial community and mimics the metabolic disturbances seen in patients. When the animals received a probiotic supplement of Clostridium butyricum, a bacterium renowned for its butyrate production, their metabolic picture improved markedly. Hyperglycaemia eased, insulin resistance declined, and perhaps most intriguingly, the disruption of circadian glucose rhythms that accompanies gestational diabetes was partially corrected. Microbial profiling of the treated animals confirmed that the supplement enriched the community of butyrate-producing bacteria and raised systemic butyrate levels, tying the metabolic benefits directly to the microbial metabolite.

The mechanistic heart of the study lies in the colon. Butyrate has long been known to act as an inhibitor of histone deacetylases, enzymes that remove acetyl groups from histone proteins and, in doing so, keep stretches of DNA tightly packed and transcriptionally silent. When the researchers examined colon tissue from the treated mice, they found that Clostridium butyricum supplementation reduced the abundance of one particular deacetylase, HDAC3, and increased the global acetylation of histone H3 at lysine 27, a chemical mark known as H3K27ac that flags active genes and their regulatory elements. In other words, the microbial metabolite appeared to be physically opening up the genome in intestinal cells.

Which genes were being opened? To find out, the team performed integrated RNA sequencing and H3K27ac chromatin immunoprecipitation sequencing in enteroendocrine cells, the hormone-producing specialists of the gut lining, treated with sodium butyrate and with agents that modulate HDAC3. The multi-omics analysis converged on a single compelling candidate: secretagogin, or SCGN, a calcium-binding protein expressed in enteroendocrine cells. Butyrate enhanced both the transcription of SCGN and the deposition of H3K27ac at its promoter, indicating that the metabolite directly activates the gene through the same epigenetic mechanism. Because SCGN has been implicated in the regulated secretion of peptide hormones, the connection to GLP-1 was an obvious next step.

The functional experiments confirmed it. Treating enteroendocrine cells with butyrate, or knocking down HDAC3 with molecular tools, increased SCGN expression and boosted the secretion of GLP-1. Conversely, when the researchers forced cells to overexpress HDAC3, the SCGN-GLP-1 axis was suppressed, but this suppression could be reversed by co-treatment with butyrate. The epigenetic brake and the microbial metabolite were locked in a push-pull relationship: HDAC3 silences the hormone-secreting programme, and butyrate releases it. This is a textbook example of how a dietary and microbial signal can be translated into a durable change in gene expression, one that ultimately shapes whole-body metabolism.

Genetic validation in living animals provided the final, decisive test. The team used mice that carry only one functional copy of the HDAC3 gene, a condition known as haploinsufficiency, which reduces the protein’s levels without eliminating it entirely. If the benefits of Clostridium butyricum truly flow through HDAC3 inhibition, then animals with less HDAC3 to begin with should gain little from the probiotic. That is precisely what the researchers observed: in HDAC3-haploinsufficient mice, the metabolic improvements and the upregulation of SCGN driven by the bacterium were abolished. The genetic experiment closes the causal loop and rules out the possibility that butyrate works through unrelated pathways.

Taken together, the study delineates what the authors describe as a novel gut microbiota-epigenetic-hormonal axis. Gut bacteria produce butyrate; butyrate inhibits HDAC3 in the intestinal lining; HDAC3 inhibition raises H3K27ac at the SCGN promoter; SCGN activation potentiates GLP-1 secretion; and GLP-1 improves glucose homeostasis for mother and fetus. Each link in this chain was tested independently, from the human correlation through the mouse intervention to the chromatin-level biochemistry and the genetic knockout. The architecture of the pathway is elegant precisely because it is specific: rather than a diffuse anti-inflammatory effect, the metabolite acts on a defined enzyme at a defined genomic target to produce a defined hormonal outcome.

The translational implications are considerable. HDAC3 and the downstream SCGN-GLP-1 pathway now stand as candidate targets for preventing or treating gestational diabetes, whether through probiotic supplementation with butyrate-producing strains such as Clostridium butyricum, dietary strategies that favour butyrate-producing communities, or future drugs that modulate HDAC3 activity in the gut. The authors note that their work was supported by the Beijing Municipal Natural Science Foundation, the National Natural Science Foundation of China and related programmes, and the study was conducted under ethics approvals for both the human cohort and the animal experiments. As with any mouse study, the road to clinical application will require trials in pregnant women, but the early-pregnancy signature of low butyrate and low GLP-1 offers a tantalising window for intervention long before the disease declares itself. For a condition that shapes the lifelong metabolic health of two generations at once, a microbial molecule that rewrites gene expression in the gut may prove to be one of the most consequential discoveries in pregnancy metabolism in years.

Subject of Research: How the gut microbial metabolite butyrate improves gestational glucose homeostasis through HDAC3 inhibition and epigenetic activation of the SCGN/GLP-1 axis

Article Title: The gut microbiota-derived butyrate improves gestational glucose homeostasis through HDAC3 inhibition and epigenetic activation of the SCGN/GLP-1 axis

Article References: Han, W., Zhang, Y., Huang, J., Lu, Y., Yin, X., Zhao, Y., Yuan, X., Yang, R., Zhang, L., Zheng, W., & Li, G. (2026). The gut microbiota-derived butyrate improves gestational glucose homeostasis through HDAC3 inhibition and epigenetic activation of the SCGN/GLP-1 axis. Journal of Translational Medicine. https://doi.org/10.1186/s12967-026-08720-y

Image Credits: AI Generated

DOI: 10.1186/s12967-026-08720-y

Keywords: gestational diabetes, butyrate, gut microbiota, HDAC3, epigenetics, GLP-1, secretagogin, Clostridium butyricum, histone acetylation, H3K27ac, enteroendocrine cells, insulin resistance