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Epigenetic regulation of type 1 diabetes in nonobese diabetic mice

ABSTRACT: Background: Epigenetic alteration of the genome has been shown to provide palliative effects in mouse models of certain human autoimmune disorders. We have investigated whether chromatin remodeling could provide protection against autoimmune diabetes in nonobese diabetic (NOD) mice. Treatment of female mice during the transition from prediabetic to diabetic stage (18-24 weeks of age) with the well-characterized histone deacetylase inhibitor, Trichostatin A (TSA) effectively reduced the incidence of diabetes and abrogated the ability of splenocytes to adoptively transfer the disease into immunodeficient NOD.scid mice. Protection against diabetes was accompanied by histone hyperacetylation in pancreas and spleen, increased frequency of CD4+ CD62L+ cells in the spleen, reduction in cellular infiltration of islets, restoration of normoglycemia and glucose-induced insulin release by beta cells. In vitro activation of splenic T lymphocytes derived from protected mice resulted in enhanced expression of IFN-gamma mRNA and protein without altering the expression of Il4, Il17, Il18, Inos, and Tnfa genes nor the secretion of IL-2, IL-4, IL-17 and TNF-alpha proteins. Consistently, expression of the transcription factor involved in Ifng transcription, Tbet/Tbx21 but not Gata3 and Rorgt, respectively required for the transcription of Il4 and Il17, was upregulated in activated splenocytes of protected mice. These data indicate that abrogation of autoimmune diabetes is associated with the selective upregulation of certain inducible genes in T lymphocytes. Microarray analysis was performed to determine the changes in global gene expression underlying abrogation of autoimmune diabetes by TSA-mediated epigenetic modulation and identified a distinct group of genes down-regulated during this process.

ORGANISM(S): Mus musculus

PROVIDER: GSE26461 | GEO | 2012/12/01

SECONDARY ACCESSION(S): PRJNA136571

REPOSITORIES: GEO

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Project description:Background: Epigenetic alteration of the genome has been shown to provide palliative effects in mouse models of certain human autoimmune disorders. We have investigated whether chromatin remodeling could provide protection against autoimmune diabetes in nonobese diabetic (NOD) mice. Treatment of female mice during the transition from prediabetic to diabetic stage (18-24 weeks of age) with the well-characterized histone deacetylase inhibitor, Trichostatin A (TSA) effectively reduced the incidence of diabetes and abrogated the ability of splenocytes to adoptively transfer the disease into immunodeficient NOD.scid mice. Protection against diabetes was accompanied by histone hyperacetylation in pancreas and spleen, increased frequency of CD4+ CD62L+ cells in the spleen, reduction in cellular infiltration of islets, restoration of normoglycemia and glucose-induced insulin release by beta cells. In vitro activation of splenic T lymphocytes derived from protected mice resulted in enhanced expression of IFN-gamma mRNA and protein without altering the expression of Il4, Il17, Il18, Inos, and Tnfa genes nor the secretion of IL-2, IL-4, IL-17 and TNF-alpha proteins. Consistently, expression of the transcription factor involved in Ifng transcription, Tbet/Tbx21 but not Gata3 and Rorgt, respectively required for the transcription of Il4 and Il17, was upregulated in activated splenocytes of protected mice. These data indicate that abrogation of autoimmune diabetes is associated with the selective upregulation of certain inducible genes in T lymphocytes. Microarray analysis was performed to determine the changes in global gene expression underlying abrogation of autoimmune diabetes by TSA-mediated epigenetic modulation and identified a distinct group of genes down-regulated during this process. Female NOD mice were treated subcutaneously with TSA (500 µg/Kg body weight) during the transition from prediabetic to diabetic stage (18-24 weeks of age), at weekly intervals. Since we sought to determine the modulation of global gene expression associated with long-term protection against diabetes, TSA treated mice were killed between 32 and 36 weeks of age and total RNA was extracted from uninduced splenocytes. RNA was also extracted from splenocytes of untreated mice that became diabetic and those that did not develop diabetes till 36 weeks of age. Blood glucose levels were determined weekly to monitor the glycemic condition in untreated and TSA-treated mice. To minimize the variability in gene expression among individual mice, RNA was extracted from splenocytes of 3 to 5 mice per group and pooled. Each sample was hybridized to microchips in duplicate. Female NOD mice were treated with Trichostatin A (500 µg/Kg body weight) between 18-24 weeks of age or left untreated.

Project description:We demonstrate diverse roles of interferonâgamma (IFN-Î³) in the induction and regulation of immune-mediated inflammation using a transfer model of autoimmune diabetes. The diabetogenic CD4+BDC2.5 (BDC) T cell clone upon transfer into NOD.scid mice induced destruction of islets of Langerhans leading to diabetes. Administration of a neutralizing antibody to IFN-Î³ (H22) resulted in long term protection (LTP) from diabetes, with inflammation but persistence of a significant, albeit decreased numbers of Î²-cells. BDC T cells were a mixture of cells expressing high, intermediate and low levels of the T cell receptor. Clonotype-low BDC T cells were required for LTP. Furthermore, islet infiltrating leukocytes in the LTP mice contained Foxp3+CD4 T cells. Islet inflammation in both diabetic and LTP mice was characterized by heavy infiltration of macrophages. Gene expression profiles indicated that macrophages in diabetic mice were M1-type, while LTP mice contained M2-differentiated. The LTP was abolished if mice were treated with either an antibody depleting CD4 T cells, or a neutralizing antibody to CTLA-4, in this case, only at a late stage. Neutralization of IL-10, TGF-Î², GITR or CD25 had no effect. Transfer of only clonotype-high expressing BDC T cells induced diabetes but in contrast, H22 antibodies did not inhibit diabetes. While clonotype high T cells induced diabetes even when IFN-Î³ was neutralized, paradoxically, there was reduced inflammation and no diabetes if host myeloid cells lacked IFN-Î³ receptor. Hence, using monoclonal CD4 T cells, IFN-Î³ can have a wide diversity of roles, depending on the setting of the immune process. Experiment Overall Design: Pancreatic islets were laser-capture microdissected from mice injected with diabetogenic T cells. One cohort of mice also received injections with anti-interfereon gamma monoclonal antibody, which protected those mice from developing diabetes. RNA prepared from islets was amplified and analyzed by Affymetrix GeneChips. Each GeneChip was prepared from RNA pooled from 5 mice at each timepoint. GeneChips were prepared from RNA extracted at different days following injection of T cells. The following days were assayed day 0 (i.e., untreated), day 3 (for diabetic and protected islets), day 4 (diabetic and protected), day 5 (only for protected, as diabetic islets were too edematous to dissect), day 8 (diabetic and protected).

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Epigenetic regulation of type 1 diabetes in nonobese diabetic mice

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