Interorgan Signaling Could Help Diabetics

Cross talk between different organs may provide a new target for scientists developing therapies to treat type 1 diabetes, according to a paper in Science (2008, 322, 1250). Working with mice, researchers led by Hideki Katagiri and Junta Imai of Tohoku University Graduate School of Medicine, in Sendai, Japan, found that the liver of obese individuals sends a directive to the pancreas to build more insulin-producing β cells, leading to high amounts of insulin in the blood stream. This signal is pathological in obese animals, which can suffer health problems from too much insulin buildup. But an insulin-producing directive could be good for type 1 diabetics for whom the pancreas does not make enough insulin. In particular, the Japanese team pinpointed a protein kinase called ERK in the liver that when activated induces the production of pancreatic β cells. When the team tried activating ERK in mouse models of type 1 diabetes, "the signaling increased β cell mass and normalized serum glucose levels," the researchers write. "Thus, interorgan metabolic relay systems may serve as valuable targets in regenerative treatments for diabetes." The search has now begun for the molecular signals involved in transmitting the message, Katagiri says.