UCP2 inhibition eliminates pancreatic β cell autoinflammation in T2DM with islet-mitochondrial sequential targeting nanomedicines.

Pancreatic β-cell dysfunction and mass loss are core pathologies of type 2 diabetes mellitus (T2DM), which are closely related to intense autoinflammation. However, the molecular mechanisms regulating β-cell autoinflammation remain unclear. Here, we show that STING is significantly elevated in T2DM β cells. We also clarify the key role of uncoupling protein 2 (UCP2), and reveal that interleukin-1β (IL-1β) drives β cells to produce autoinflammation through the UCP2/mtDNA/STING axis in T2DM. To inhibit UCP2 activity in vivo, we design a tailored nanomedicine, Mito-G, with sequential targeting from islets to β-cell mitochondria. Mito-G is a negatively charged ultra-small nanomedicine synthesized by polymerization of genipin (a potent UCP2 inhibitor) and glycine. It can specifically reach β cells and have a natural mitochondrial targeting. In this work, Mito-G effectively eliminates β-cell auto-inflammation by specifically inhibiting β-cell UCP2 activity in vivo, providing a paradigm for targeting autoinflammation of β cells to treat T2DM.