A Viral Infection that Might One Day Cure Diabetes

Scientists have used gene therapy to make insulin-producing cells in a mouse's pancreas
Insulin producing cells (like the ones shown in green) have
been made in a mouse's pancreas. Photo credit by Masur.
A new study out in Nature shows how to turn one kind of pancreas cell into an insulin-producing islet cell. This research is an important step in finding a cure for Type 1 diabetes.

People get Type 1 diabetes when their bodies attack and destroy their own islet cells. These people can't make insulin anymore and so have to inject it. The best cure would be if scientists could replace the old islet cells with new ones. This is what the researchers in this study set out to do in mice.

The researchers made islet cells directly in a mouse’s pancreas. They did this by using gene therapy to reprogram one type of pancreas cell (an exocrine cell) into islet cells.

All cells share the same DNA. What makes each cell type different is which genes are on (or have been on in the past). Proteins called transcription factors are a big part of this programming.

The authors reasoned that they might be able to directly reprogram one kind of adult cell into another by adding the right mix of transcription factors. They couldn't just add transcription factors though. Instead, they added transcription factor genes*.

Finding the right transcription factors was not simple. There are thousands of these things scattered throughout our DNA.

The researchers narrowed the list of possible candidates down by looking at those that were found in the pancreas. And then they further narrowed down the candidates by mutating these transcription factor genes and looking for effects on pancreas development. Nine transcription factors made it through these tests.

By testing different combinations of these genes, the authors were able to find a cocktail of three that turned an exocrine cell into an islet cell. These new cells looked and acted like islet cells. And what is also important, the new cells stayed islet cells even after the transcription factors were gone.

One of the big problems with gene therapy is that eventually the body recognizes the viral DNA as other and shuts it down. So the best gene therapies are the ones like this--the hit and run kind.

This is all very promising but the procedure is nowhere near ready for prime time yet. One problem, of course, is that mice aren't people. What worked in a mouse might not work in a person.

An even bigger problem is that the created islet cells are scattered here and there throughout the pancreas. Islet cells work best in clumps (as they exist naturally). So scientists will need to figure out how to get them to clump together.

* Transcription factors are proteins and like all proteins, their instructions are found in genes.

37.332 -121.903