Scientists genetically modify bacteria to detect & treat intestinal diseases, incl cancer

Reuters / Manfred Rohde
Bacteria in the human digestive system can be programmed to register, report and even treat diseases as grave as cancer. All it takes is a little bit of genetic engineering.

A group of scientists from the Massachusetts Institute of Technology have managed to genetically modify a human gut bacterium so that it could detect and report the symptoms of digestive diseases, thus opening the potential for new innovative medical treatments.

The MIT research team led by Timothy Lu, an associate professor of computer science and biological and electrical engineering, and Christopher Voigt, a professor of biological engineering, enhanced a common human gut microbe with specific proteins, enabling them to record and store information about changes in the bacterium’s DNA.

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The scientists used the results of previous experiments on the genetic modification of bacteria in their work.

The team conducted their first experiments on E. coli bacterium, which is often regarded as a model organism for such studies.

However, this bacterium is rather uncommon in the human body, accounting for only 0.1% of human intestinal bacteria. Consequently, the researchers decided to switch to a specific species of microbe within the Bacteroids type, B. thetaiotaomicro, as it makes up around 12% of bacteria in the human digestive system and is present in 46% of people, as reported by Live Science.

“We wanted to work with [bacteria] that are present in many people in abundant levels, and can stably colonize the gut for long periods of time,” Professor Timothy Lu says.

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The team developed several genetic modifications allowing the scientists to accurately program bacteria to detect and potentially treat such diseases as inflammatory bowel disease or colon cancer.

Their research findings were published in Cell Systems and in an MIT press release.

Reuters / Oleg Popov

The scientists used the guts of mice to demonstrate how their genetic bacterial enhancements function.

“We then showed that genetic devices could be implemented in the bacteria and be shown to function in the context of the mouse gut microbiome,” said Lu.

The experiments showed that bacteria could remember the food the mice were fed, meaning it is possible that it could also record symptoms of different intestine diseases.

“This could be a powerful platform for human therapeutics,”Professor Christopher Voigtsaid.

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The team now plans to expand their genetic modification technology to other bacterial species, as different people have different types of dominant bacteria in their gut.

In addition, the scientists also plan to experiment on microbes living elsewhere in the human body, as well as to engineer them with more complex behavior patterns.

“We could engineer bacteria to detect multiple biomarkers, and only trigger a response when they are all present,” Lu says.

The study has already received a positive evaluation from other scientists.

This research opens new possibilities for creating engineered cells capable of performing such tasks as “sensing and recording, or even synthesis of therapeutic molecules,” said Tom Ellis from the Centre for Synthetic Biology at Imperial College London.