Engineered gut bacteria release GLP-1 on demand in diabetic animals

A pill containing engineered bacteria may one day answer a glucose spike without waiting for the next injection. In a Nature study, researchers in Shanghai gave their oral probiotic, GIFT, to diabetic mice and naturally diabetic monkeys; the bacteria sensed rising glucose and released GLP-1, a hormone that prompts insulin release and helps lower blood sugar.

GIFT is built from the probiotic bacterium Escherichia coli Nissle 1917. Its molecular switch uses HexR, a sensor protein: when glucose enters the bacterium, its metabolism produces KDPG, which releases HexR from a genetic promoter and activates the genes that make GLP-1. When glucose falls back into a healthy range, the bacteria switch hormone production off.

The animal results point to a treatment that could dose itself more closely to the body’s immediate needs. After sugary food, treated mice avoided extreme blood sugar surges. In naturally diabetic monkeys, probiotics given every three days for five weeks improved glucose control, insulin resistance and cholesterol profiles; a single oral dose kept blood sugar under control for up to three days.

The team also tried to keep the living drug active in the gut. Coating the bacteria with tannic acid and poloxamer 188 extended their active intestinal presence in mice from 8 hours to 36 hours. After 30 days of daily treatment, diabetic mice showed reduced fat mass and weight gain, alongside improvements in blood fats and measures linked to liver and kidney protection. In a comparison with semaglutide, the probiotic appeared less likely to cause low blood sugar when combined with insulin, while treated mice preserved or slightly increased lean muscle mass.

So what changes in practice? Not yet a prescription: the work has been done in animals, and no human trial is reported. But the concept targets a real weakness of fixed-dose treatment—an injection can deliver a high, scheduled dose even when glucose needs have changed. GIFT could instead provide an oral, temporary and glucose-responsive delivery system, if future safety and stability studies support the approach. Because it uses a genetically modified organism, clinical use would also require regulatory approval.