New cause of diabetes discovered, offering potential target for new classes of drugs to treat the disease

Researchers have identified an enzyme that blocks insulin produced in the body-a discovery that could provide a new target to treat diabetes. The study, released on December 5 in the journal cell, focuses on nitric oxide, a compound that dilates blood vessels, improves memory, fights infection and stimulates the release of hormones, among other functions. How nitric oxide performs these activities had long been a mystery.

The researchers discovered a novel "carrier" enzyme (called SNO-CoA-assisted nitrosylase, or SCAN) that attaches nitric oxide to proteins, including the receptor for insulin action.

They found that the SCAN enzyme was essential for normal insulin action, but also discovered heightened SCAN activity in diabetic patients and mice with diabetes.

Mouse models without the SCAN enzyme appeared to be shielded from diabetes, suggesting that too much nitric oxide on proteins may be a cause of such diseases.

With this discovery, Stamler said, enzymes that attach the nitric oxide become a focus.

With diabetes, the body often stops responding normally to insulin.

The resulting increased blood sugar stays in the bloodstream and, over time, can cause serious health problems.

Reference: Hua-Lin Zhou, Zachary W. Grimmett, Nicholas M. Venetos, Colin T. Stomberski, Zhaoxia Qian, Precious J. McLaughlin, Puneet K. Bansal, Rongli Zhang, James D. Reynolds, Richard T. Premont, Jonathan S. Stamler. An enzyme that selectively S-nitrosylates proteins to regulate insulin signaling. Cell, 2023; DOI: 10.1016/j.cell.2023.11.009