Conditional and specific inhibition of NF-κB in mouse pancreatic cells prevents cytokine-induced deleterious effects and improves islet survival posttransplant

Background. Islets are susceptible to damage by proinflammatory cytokines via activation of transcription factor NF-kappa B. We hypothesized that inhibition of NF-kappa B activity will decrease cytokine mediated beta-cell injury and improve islet transplant functional outcome. Methods. We created a transgenic mouse expressing a degradation resistant N-terminally deleted I kappa B alpha (Delta NI kappa B alpha) under the control of a commercially available,tetracycline-controlled transcriptional activation system using a rat insulin promoter. Isolated islets from transgenic and control mouse strains were exposed to cytokines in vitro and assayed or transplanted. Results. Western blot analysis showed that Delta NI kappa B alpha was significantly increased with doxycycline treatment. Cytokine-induced NF-kappa B activation was significantly decreased in transgenic (0.065 +/- 0.013 absorbance value/mu g protein) vs control islets (0.128 +/- 0.006; P < .05). Suppression of cytokine-mediated NF-kappa B activity decreased expression of inducible nitric oxide synthase, monocyte chemoattractant protein-1, and interferon-gamma inducible protein-10 RNA transcripts, and significantly decreased nitric oxide production in transgenic islets (0.084 +/- 0.043 mu M/Ag protein) vs controls (0.594 +/- 0.174; P <.01). The insulin stimulation index in islets exposed to cytokines was higher in transgenic vs controls (1.500 +/- 0.106 vs 0.800 +/- 0.098; P <.01). Syngeneic transplants of a marginal mass of intraportally infused transgenic islets resulted in a reversion to euglycemia in 69.2% of diabetic recipients at a mean of 7.8 +/- 1.1 days vs 35.7% of control islet recipients reverting at a mean of 15.8 +/- 2.9 days <.05). Conclusion. Conditional and specific suppression of NF-kappa B activity in beta cells protected islets from cytokine-induced dysfunction in vitro and in vivo. These results provide a proof of principle that inhibition of NF-kappa B activity in donor islets enhances function and improves the outcome of islet transplantation. (Surgery 2012;151:330-9.)