Inhibition of the eukaryotic initiation factor-2[alpha] kinase PERK decreases risk of autoimmune diabetes in mice

Preventing the onset of autoimmune type 1 diabetes (T1D) is feasible through pharmacological interventions that target molecular stress-responsive mechanisms. Cellular stresses, such as nutrient deficiency, viral infection, or unfolded proteins, trigger the integrated stress response (ISR), which curtails protein synthesis by phosphorylating eukaryotic translation initiation factor-2[alpha] (eIF2[alpha]). In T1D, maladaptive unfolded protein response (UPR) in insulin-producing [beta] cells renders these cells susceptible to autoimmunity. We found that inhibition of the eIF2a kinase PKR-like ER kinase (PERK), a common component of the UPR and ISR, reversed the mRNA translation block in stressed human islets and delayed the onset of diabetes, reduced islet inflammation, and preserved [beta] cell mass in T1D-susceptible mice. Single-cell RNA-Seq of islets from PERK-inhibited mice showed reductions in the UPR and PERK signaling pathways and alterations in antigen-processing and presentation pathways in p cells. Spatial proteomics of islets from these mice showed an increase in the immune checkpoint protein programmed death-ligand 1 (PD-L1) in [beta] cells. Golgi membrane protein 1, whose levels increased following PERK inhibition in human islets and EndoC-[beta]H1 human [beta] cells, interacted with and stabilized PD-L1. Collectively, our studies show that PERK activity enhances [beta] cell immunogenicity and that inhibition of PERK may offer a strategy for preventing or delaying the development of T1D.
Introduction Type 1 diabetes (T1D) is a disorder of glucose homeostasis that results from the autoimmune destruction of insulin-producing islet [beta] cells. The importance of the immune system in initiating [...]