Aims/hypothesis: Islet cell death is a key initiating and perpetuating event in type 1 diabetes and involves both immune-mediated and endogenous mechanisms. The epithelial pantetheinase vanin-1 is proinflammatory and cytoprotective via cysteamine release in some tissues. We investigated the impact of a vanin-1 deficiency on islet death and type 1 diabetes incidence.
Methods: Vanin-1-deficient mice were produced and tested in drug-induced and autoimmune diabetes models. The contribution of vanin-1 to islet survival versus immune responses was evaluated using lymphocyte transfer and islet culture experiments.
Results: The vanin-1/cysteamine pathway contributes to the protection of islet beta cells from streptozotocin-induced death in vitro and in vivo. Furthermore, vanin-1-deficient NOD mice showed a significant aggravation of diabetes, which depended upon loss of vanin-1 expression by host tissues. This increased islet fragility was accompanied by greater CD4+ insulitis without impairment of regulatory cells. Addition of cystamine, the product of pantetheinase activity, protected islets in vitro and compensated for vanin-1 deficiency in vivo.
Conclusions/interpretation: This study unravels a major cytoprotective role of cysteamine for islet cells and suggests that modulation of pantetheinase activity may offer alternative strategies to maintain islet cell homeostasis.