Nanoparticles that teach immune cells tolerance could treat diabetes

People with type 1 diabetes struggle to produce insulin because their immune system attacks cells in the pancreas that make the sugar-regulating hormone. A team of researchers has designed functionalized nanoparticles that can reprogram immune cells in diabetic mice to stop assaulting the insulin-producing cells (Sci. Signaling 2016, DOI: 10.1126/scisignal.aad0612). To reestablish what’s called immune tolerance for pancreatic cells, Francisco J. Quintana of Harvard Medical School and coworkers decorated gold nanoparticles with two molecules: insulin and 2-(1´-H-indole-3´-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE). Once immune cells called dendritic cells take up the nanoparticles, ITE activates a transcription factor that turns on pathways involved in releasing signaling molecules directed at T cells. These molecules stop damage-inducing inflammation by telling T cells to stand down. The insulin molecules carried by the gold particles help target the dendritic cells’ message toward T cells attacking pancreatic cells. When the team injected the nanoparticles into mice that can develop type 1 diabetes spontaneously, about 25% of the animals became diabetic. For untreated mice, the incidence was about 75%. Quintana thinks similar particles could be designed for other autoimmune diseases such as multiple sclerosis.