When is a cell like a computer?

The cell–the most fundamental unit of life–could one day be as easily programmable as a computer, according to Mark Weiss, professor of electrical engineering and molecular biology at Princeton University.

Weiss envisions a day when cells can be programmed to do things like treat diabetes and cancer, clean up the environment and perhaps even become part of an artificial immune system. He laid out his vision of the future recently in a talk at the Polytechnic University in Brooklyn.

“We don’t expect to take bacteria and have them run Microsoft Excel” Weiss jokingly told the crowd of 60 or so faculty and students.

In fact, Weiss’ recent work is more akin to computer programming in its infancy–very basic programs that take a long time to run. However, he has had some success in tinkering with the genes of bacterial cells and even mammalian stem cells to make them run these very basic binary programs. For instance, he has created bacterial cells that can evaluate basic logical statements.

The work Weiss is doing is part of a relatively new area of research known as synthetic biology. It draws on knowledge from various disciplines to create new or modified life forms, or networks of life forms, that can perform specific functions.

J. Craig Venter, the famed molecular biologist and sequencer of the human genome, has drawn attention to the field in his quest to completely synthesize a bacterial genome, insert it into an empty cell and ‘boot up’ the cell to create a nearly artificial life form.

However, rather than create artificial life forms from scratch, Weiss’ idea is to be able to create them by mixing and matching pre-defined modules of genetics circuits. He imagines engineers of the future designing lifeforms using a “bioprogramming” language, a computer code-like shorthand that will allow them to link together these genetic circuits via computer into complex networks.

The genetic “circuits” Weiss refers to are actually genes from different organisms linked together on a single stretch of DNA, which work together to do something completely different than their original function. These circuits, once inserted into stem cells, would nudge them into developing in a different direction.

In addition, Weiss is looking at ways to design cells with circuits so that they can work in tandem, relaying information between cells via proteins. During his lecture, Weiss showed brilliantly-colored patterns of bacterial cells created by this method.

Similarly, he thinks that genetic circuits could be used to alter stem cell communication, inducing them to create patterns of cells that would grow into artificially-produced tissues and organs. Taking his idea even further, he speculated that we might even be able to create enhanced tissues this way.

“In theory we might be able to create better parts than their natural counterparts” said Weiss.

Weiss’ presentation was largely speculative, and he repeatedly pointed out that the research is still very preliminary. Some in the crowd were openly skeptical. One unidentified member of the audience exclaimed “It’s unbelievable,” referring to Weiss’ claim that these circuits could someday be implanted in stem cells and steer their development.

Weiss acknowledged that no one is exactly sure how stem cells will respond to the implanted genetic circuits, and that their response may be heavily dependent on environmental factors such as temperature and acidity.

He is currently looking at ways to treat Type I diabetes by engineering the stem cells that create insulin-producing cells in the pancreas. These cells are killed by the body’s own immune system in people with Type I diabetes.

Weiss’s lecture was part of a seminar series hosted by Polytechnic’s Department of Chemical and Biological Engineering.