From immunobiology to β-cell biology The changing perspective on type 1 diabetes

Type 1 Diabetes (T1D) is characterized by the immune mediated destruction of beta cells. Clinical studies have focused on drug therapies to modulate autoimmunity, yet none of these interventions has resulted in durable preservation of beta-cell function. These findings raise the possibility that initiating or propagating events outside of the immune system should be considered in future efforts to prevent or reverse T1D. An emerging concept suggests that defects inherent to the beta cell may trigger autoimmunity. A study by Engin et al. in type 1 diabetic NOD mice suggests that excessive beta-cell endoplasmic reticulum stress arising from environmental insults results in abnormal protein synthesis, folding, and/or processing. Administration of the chemical protein folding chaperone TUDCA resulted in recovery of beta-cell endoplasmic reticulum function and a diminished incidence of diabetes in NOD mice. We propose here that these data and others support a model whereby an inadequate or defective beta-cell endoplasmic reticulum response results in the release of beta-cell antigens and neoantigens that initiate autoimmunity. Pharmacologic therapies that either mitigate these early beta-cell stressors or enhance the ability of beta cells to cope with such stressors may prove to be effective in the prevention or treatment of T1D.