Intracellular calcium stores as master regulators of pancreatic beta-cell survival: studies on transplantable human islets and knockout mice

Canada has a growing diabetes epidemic, which costs the Canadian health care system an estimated $13 billion annually. More than two million Canadians have the disease, and by 2010, the number is expected to increase to three million. Diabetes is also a major health problem worldwide. Although diabetes can be treated with insulin, a cure for this devastating disease remains elusive. All forms of diabetes are associated with the loss of functional pancreatic islet cells. However, very little is known about the underlying factors controlling how and why pancreatic islet cells die. Dr. James Johnson recently discovered important networks of molecules that control survival of islet cells. For example, one such network includes the RyR2 protein, which controls the release of calcium in the cell, and the calpain protein, which can split other proteins in response to increased calcium. Dr. Johnson is comparing the role of this survival network to other molecular networks to investigate how pancreatic islet cells die. The research could lead to better therapies for diabetes, including more successful pancreatic islet transplantation, a promising experimental treatment that depends critically on the continued survival of the donated cells. The findings could also improve understanding of other diseases where calcium is involved in cell death, such as heart failure, Alzheimer’s disease and stroke.