Effects of combination therapy with dipeptidyl peptidase-IV and histone deacetylase inhibitors in the non-obese diabetic mouse model of type 1 diabetes

Authors

  • S. M. Cabrera,

    1. Department of Pediatrics and the Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN
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  • S. C. Colvin,

    1. Department of Pediatrics and the Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN
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  • S. A. Tersey,

    1. Department of Pediatrics and the Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN
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  • B. Maier,

    1. Department of Pediatrics and the Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN
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  • J. L. Nadler,

    1. Department of Medicine and the Strelitz Diabetes Center, Eastern Virginia Medical School, Norfolk, VA, USA
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  • R. G. Mirmira

    Corresponding author
    1. Department of Medicine, Indiana University School of Medicine, Indianapolis, IN
    2. Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN
    3. Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN
    • Department of Pediatrics and the Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN
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Correspondence: R. G. Mirmira, Indiana University School of Medicine, 635 Barnhill Drive, MS2031B, Indianapolis, IN 46202, USA.

E-mail: rmirmira@iupui.edu

Summary

Type 1 diabetes (T1D) results from T helper type 1 (Th1)-mediated autoimmune destruction of insulin-producing β cells. Novel experimental therapies for T1D target immunomodulation, β cell survival and inflammation. We examined combination therapy with the dipeptidyl peptidase-IV inhibitor MK-626 and the histone deacetylase inhibitor vorinostat in the non-obese diabetic (NOD) mouse model of T1D. We hypothesized that combination therapy would ameliorate T1D by providing protection from β cell inflammatory destruction while simultaneously shifting the immune response towards immune-tolerizing regulatory T cells (Tregs). Although neither mono- nor combination therapies with MK-626 and vorinostat caused disease remission in diabetic NOD mice, the combination of MK-626 and vorinostat increased β cell area and reduced the mean insulitis score compared to diabetic control mice. In prediabetic NOD mice, MK-626 monotherapy resulted in improved glucose tolerance, a reduction in mean insulitis score and an increase in pancreatic lymph node Treg percentage, and combination therapy with MK-626 and vorinostat increased pancreatic lymph node Treg percentage. We conclude that neither single nor combination therapies using MK-626 and vorinostat induce diabetes remission in NOD mice, but combination therapy appears to have beneficial effects on β cell area, insulitis and Treg populations. Combinations of vorinostat and MK-626 may serve as beneficial adjunctive therapy in clinical trials for T1D prevention or remission.

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