Genetically engineered probiotic with a gene circuit successfully regulates blood sugar in primates for 3 days in an experimental setting.
Background
Lifelong blood sugar management is essential for individuals with diabetes to maintain a normal life. Current widely used treatments rely on direct injection of insulin or glucagon-like peptide-1 (GLP-1) analogs. This approach is a major cause of poor adherence due to pain and inconvenience. Furthermore, because the drug is secreted regardless of glucose levels, there is a high risk of causing hypoglycemic shock or gastrointestinal side effects. There is a need for an intelligent system that can actively respond to real-time changes in blood sugar.
Research has been conducted to address this by transplanting pancreatic islet cells, but it has been hindered by immune rejection and cell shortage. Artificial pancreas devices also have limitations in terms of invasive administration and complex device management. As a result, a synthetic biology approach that designs microorganisms with gene circuits to function as blood sugar sensors in the gut has emerged as an alternative.
Key Findings
The research team, led by Professor Ye Haifeng and researcher Guan Ningzi at East China Normal University, has developed 'GIFT (Glucose sensing and functional response probiotic)', an oral therapeutic microorganism equipped with a synthetic gene circuit. The team utilizes the safety-validated Escherichia coli Nissle 1917 (EcN) as a drug delivery vehicle. This strain is engineered with a glucose-sensing protein, HexR, derived from Pseudomonas putida, and an artificial promoter-based circuit.
The designed gene circuit operates with a precise autonomous mechanism. When glucose levels are low, HexR remains bound to the promoter, inhibiting the production of the therapeutic agent. After a meal, glucose enters the system, leading to the accumulation of 2-keto-3-deoxy-6-phosphogluconate (KDPG), a glucose metabolite. KDPG binds to HexR, causing a conformational change that releases it from the promoter. When the switch is activated, the therapeutic agent GLP-1 is rapidly released from the bacteria via a secretion sequence. When blood sugar levels decrease, the supply of metabolites stops, and drug release is immediately halted.
The efficacy was demonstrated in diabetic mice and marmoset monkey experiments. In the mouse model, postprandial blood sugar spikes were controlled. In particular, in the marmoset monkey model, a single dose resulted in a blood sugar-lowering effect that lasted for 3 days (72 hours). Long-term administration for 5 weeks, with a 3-day interval, demonstrated stable blood sugar control without adverse effects.
Significance and Prospects
This study demonstrates that a microbial-based autonomous control technology can complement the shortcomings of existing treatments. Existing injectable drugs have difficulty responding quickly to blood sugar fluctuations, posing a risk of hypoglycemic shock. In contrast, smart microorganisms that release drugs in response to glucose levels have the advantage of inducing blood sugar stabilization at a level comparable to that of the endocrine system. By increasing the drug administration interval to 3 days, it is expected to improve the quality of life for patients.
The results also showed that long-term administration inhibited complications. The levels of diabetic dyslipidemia, impaired renal function, and retinal degeneration were significantly lower in the treatment group. This suggests that it has the ability to improve not only blood sugar control but also overall metabolic diseases. The fact that gastrointestinal discomfort or hypersensitivity reactions, which are observed in the injectable drug group, were not observed is also encouraging.
However, there are several challenges that need to be addressed before this technology can be applied in clinical practice. The impact of genetically modified probiotics on the gut ecosystem and the risk of unexpected mutations need to be verified in the future. The colonization rate may vary depending on the individual's gut environment. In the future, the safety can be ensured by reinforcing the circuit to allow it to act for a certain period of time and then self-destruct, and by conducting human clinical trials.
Nature, Published online: 12 August 2026; doi:10.1038/d41586-026-02521-5Genetically modified bacteria lower high blood-sugar in animal trials — plus, how to watch a solar eclipse safely.
GIFT technology has the potential to be a turning point in changing the daily lives of people with diabetes in a patient-friendly way. Patients who had to inject themselves with a needle every day or once a week can now take a capsule once every three days with water to reduce the fear of blood sugar spikes. Unlike existing protein therapeutics that require cold chain distribution, it can be formulated in a lyophilized form, making it easy to store at room temperature and transport over long distances. This is expected to open the way for stable supply to developing countries and medically underserved areas where cold storage facilities are poor. Furthermore, by simply replacing the protein gene switch that secretes the protein according to the patient's condition or disease type, it is promising to expand the technology to other chronic diseases such as obesity and metabolic syndrome and to implement personalized precision medicine.