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Altered Connexin 43 Expression Underlies Age-Dependent Decrease Of Regulatory T Cell Suppressor Function In Nonobese Diabetic Mice, Michel Kuczma, Cong-Yi Wang, Leszek Ignatowicz, Robert Gourdi, Piotr Kraj
Altered Connexin 43 Expression Underlies Age-Dependent Decrease Of Regulatory T Cell Suppressor Function In Nonobese Diabetic Mice, Michel Kuczma, Cong-Yi Wang, Leszek Ignatowicz, Robert Gourdi, Piotr Kraj
Biological Sciences Faculty Publications
Type 1 diabetes is one of the most extensively studied autoimmune diseases, but the cellular and molecular mechanisms leading to T cell–mediated destruction of insulin-producing β cells are still not well understood. In this study, we show that regulatory T cells (Tregs) in NOD mice undergo age-dependent loss of suppressor functions exacerbated by the decreased ability of activated effector T cells to upregulate Foxp3 and generate Tregs in the peripheral organs. This age-dependent loss is associated with reduced intercellular communication mediated by gap junctions, which is caused by impaired upregulation and decreased expression of connexin 43. Regulatory …
Camp-Dependent Protein Kinase Activation Lowers Hepatocyte Camp, Jackie D. Corbin, Stephen J. Beebe, Peter F. Blackmore
Camp-Dependent Protein Kinase Activation Lowers Hepatocyte Camp, Jackie D. Corbin, Stephen J. Beebe, Peter F. Blackmore
Bioelectrics Publications
Rat hepatocyte protein kinase was activated by incubating the cells with various cAMP analogs. Boiled extracts were then prepared and Sephadex G-25 chromatography was carried out. The G-25 procedure separated the analogs from cAMP since the resin had the unexpected property of binding cyclic nucleotides with differing affinities. Separation was necessary because the analogs would otherwise interfere with the sensitive protein kinase activation method developed for assay of cAMP. The cAMP analogs, but not 5'-AMP, lowered basal cAMP by 50-70%. The effect was rapid, analog concentration-dependent, and occurred parallel with phosphorylase activation, suggesting that the cAMP analogs act through cAMP-dependent …