Thursday, February 21, 2013

The Nice, Unhealthy As well as histone deacetylase inhibitor IEM 1754

We measured blood glucose levels in PancMet KO and WT mice for the duration of 20 days after the rst STZ injection. MLDS treated PancMet KO mice displayed signicantly improved blood glucose levels compared with WT mice from day 4 to day 20.

This decrease was not resulting from diminished amount of islets or decreased b cell neogenesis, measured as the amount of singlet and doublet insulin positive cells while in the pancreas, but to a reduction of histone deacetylase inhibitor insulin positive area per islet. The number of islets with. 80% insulin positive area was markedly and signicantly decreased in PancMet KO mice compared with WT littermates. Conversely, the number of islets with,20% insulin positive area was signicantly increased in PancMet KO mice, suggesting a decrease in the number of insulin positive cells per islet in these mice. An increase in b cell death would likely explain the decrease in insulinpositive cells per islet and the diminished b cell mass in PancMet KO mice compared with WT littermates. Indeed, the percentage of TUNEL positive b cells at day 8 after the rst STZ injection was strikingly and signicantly increased in PancMet KO mice, even when compared with the expected cell death in WT mice treated with MLDS.

Determination of insulitis degree showed that the number of islets without PARP inltration was signicantly decreased, and the number of islets with clear inltration was signicantly increased, in PancMet KO compared with WT mice. Chemokines and cytokines are mediators of the immune response by IEM 1754 attracting and activating leukocytes. Because PancMet KO mice display increased lymphocyte inltration, we measured the level of the secreted chemokines MCP 1 and MIG from PancMet KO and WT mouse islets exposed to cytokines. As shown in Fig. 5F and G, cytokineinduced chemokine secretion is signicantly increased in PancMet KO compared with WT mouse islets. PancMet KO b cells are more sensitive to STZ and cytokine mediated cell death.

Therefore, we examined activation of NF kB as measured by phosphorylated p65/RelA in cytokine treated islets and found enhanced phospho p65 levels in PancMet KO mouse islets compared with WT islets. iNOS is a well known NF kB target gene induced by cytokines.

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