CHOP deletion does not impact the development of diabetes but suppresses the early production of insulin autoantibody in the NOD mouse.

C/EBP homologous protein (CHOP) has been proposed as a key transcription factor for endoplasmic reticulum (ER) stress-mediated β-cell death induced by inflammatory cytokines in vitro. However, the contribution of CHOP induction to the pathogenesis of type 1 diabetes is not yet clear. To evaluate the relevance of CHOP in the pathogenesis of type 1 diabetes in vivo, we generated CHOP-deficient non-obese diabetic (NOD.Chop (-/-)) mice. CHOP deficiency did not affect the development of insulitis and diabetes and apoptosis in β-cells. Interestingly, NOD.Chop (-/-) mice exhibited a delayed appearance of insulin autoantibodies compared to wild-type (wt) mice. Adoptive transfer with the diabetogenic, whole or CD8(+)-depleted splenocytes induced β-cell apoptosis and the rapid onset of diabetes in the irradiated NOD.Chop (-/-) recipients with similar kinetics as in wt mice. Expression of ER stress-associated genes was not significantly up-regulated in the islets from NOD.Chop (-/-) compared to those from wt mice or NOD-scid mice. These findings suggest that CHOP expression is independent of the development of insulitis and diabetes but might affect the early production of insulin autoantibodies in the NOD mouse.