Protection Against Type 1 Diabetes Development in Mice With 4E-BP2 Deletion.

Abstract

Type 1 diabetes (T1D) is an autoimmune disease characterized by β-cell destruction promoted by autoreactive T cells. Eukaryotic translation initiation factor 4E (eIF4E)–binding protein 1 (4E-BP1) and 4E-BP2 are translational repressors and downstream targets of mammalian target of rapamycin complex 1 (mTORC1). Activation of the 4E-BP2/eIF4E pathway by 4E-BP2 deletion promotes translation initiation, inducing β-cell expansion and proliferation and regulating adaptive immunity. However, the involvement of 4E-BP2 in T1D remains unexplored. This study aimed to determine the role of 4E-BP2/eIF4E signaling in T1D prevention. We used the NOD mouse model of T1D and generated mice with global 4E-BP2 deletion in the NOD background (Eif4ebp2−/−). We assessed T1D development, glucose homeostasis, pancreas morphometry, and immune responses in Eif4ebp2−/− and littermate control mice. We found that Eif4ebp2−/− male mice exhibited reduced diabetes incidence, which did not occur in female mice, as well as preserved β-cell mass, improved insulin secretion in vitro, and comparable insulitis. Characterization of T-cell compartments showed decreased splenic CD8+ cytotoxic T-cell proliferation and increased pancreatic regulatory T-cell infiltration in Eif4ebp2−/− mice, potentially resulting from increased proliferation and suppressive capacity. Adoptive transfer studies demonstrated that Eif4ebp2−/− male lymphocytes were less diabetogenic than those of controls. In conclusion, activation of 4E-BP2/eIF4E by 4E-BP2 deletion protected against T1D, supporting 4E-BP2 as a potential therapy target. Mammalian target of rapamycin complex 1 (mTORC1) signaling is essential to β-cell mass, function, and adaptive immunity; however, its specific downstream mediators in type 1 diabetes (T1D) remain poorly defined. We investigated eukaryotic translation initiation factor 4E-binding protein 2 (4E-BP2), a major translational regulator downstream of mTORC1, by using global 4E-BP2-knockout mice on the NOD background. Loss of 4E-BP2 protected male NOD mice from T1D through preservation of β-cell mass and function, coupled with attenuation of autoimmune responses. These findings identify 4E-BP2 as a novel immunometabolic node, highlighting its potential as a therapeutic target for T1D prevention and treatment.