Project description:Type 1 diabetes is a multigenic disease caused by T-cell mediated destruction of the insulin producing β-cells. Although conventional (targeted) approaches of identifying causative genes have advanced our knowledge of this disease, many questions remain unanswered. Using a whole molecular systems study, we unraveled the genes/molecular pathways that are altered in CD4 T-cells from young NOD mice prior to insulitis (lymphocytic infiltration into the pancreas). Many of the CD4 T-cell altered genes lie within known diabetes susceptibility regions (Idd), including several genes in the diabetes resistance region Idd13 and two genes (Khdrbs1 and Ptp4a2) in the CD4 T-cell diabetogenic activity region Idd9/11. Alterations involved apoptosis/cell proliferation and metabolic pathways (predominant at 2 weeks), inflammation and cell signaling/activation (predominant at 3 weeks), and innate and adaptive immune responses (predominant at 4 weeks). We identified several factors that may regulate these abnormalities: IRF-1, HNF4A, TP53, BCL2L1 (lies within Idd13), IFNG, IL4, IL15, and prostaglandin E2, which were common to all 3 ages; AR and IL6 to 2 and 4 weeks; and Interferon (IFN-I) and IRF-7 to 3 and 4 weeks. Others were unique to the various ages (e. g. MYC, JUN, and APP to 2 weeks; TNF, TGFB1, NFKB, ERK, and p38MAPK to 3 weeks; and IL12 and STAT4 to 4 weeks). Our data suggest that diabetes resistance genes in Idd13 and Idd9/11, and BCL2L1, IL6-AR and IFNG-IRF-1-IFN-I/IRF-7-IL12 pathways play an important role in CD4 T-cells in the early pathogenesis of autoimmune diabetes. Thus, the alternative approach of investigation at the molecular systems level has captured new information, which combined with validation studies, offers the opportunity to test hypotheses on the role played by the genes/molecular pathways identified in this study, to understand better the mechanisms of autoimmune diabetes in CD4 T-cells, and to develop new therapeutic strategies for the disease. CD4 T-cells were purified from spleen leukocytes collected from 2-, 3- and 4-week old NOD mice and two age-matched control strains, NOR, and C57BL/6, (n=5 for each strain and each age group; except NOD2wk). NOR is an insulitis- and diabetes-free control strain that shares shares ~88% of its genome with NOD mice, including the diabetogenic H2g7 MHC haplotype and several important non-MHC T1D susceptibility loci. C57BL/6 is also a diabetes-resitant strain, but it is more genetically distantly related to NOD.

Project description:Type 1 diabetes is a multigenic disease caused by T-cell mediated destruction of the insulin producing β-cells. Although conventional (targeted) approaches of identifying causative genes have advanced our knowledge of this disease, many questions remain unanswered. Using a whole molecular systems study, we unraveled the genes/molecular pathways that are altered in CD4 T-cells from young NOD mice prior to insulitis (lymphocytic infiltration into the pancreas). Many of the CD4 T-cell altered genes lie within known diabetes susceptibility regions (Idd), including several genes in the diabetes resistance region Idd13 and two genes (Khdrbs1 and Ptp4a2) in the CD4 T-cell diabetogenic activity region Idd9/11. Alterations involved apoptosis/cell proliferation and metabolic pathways (predominant at 2 weeks), inflammation and cell signaling/activation (predominant at 3 weeks), and innate and adaptive immune responses (predominant at 4 weeks). We identified several factors that may regulate these abnormalities: IRF-1, HNF4A, TP53, BCL2L1 (lies within Idd13), IFNG, IL4, IL15, and prostaglandin E2, which were common to all 3 ages; AR and IL6 to 2 and 4 weeks; and Interferon (IFN-I) and IRF-7 to 3 and 4 weeks. Others were unique to the various ages (e. g. MYC, JUN, and APP to 2 weeks; TNF, TGFB1, NFKB, ERK, and p38MAPK to 3 weeks; and IL12 and STAT4 to 4 weeks). Our data suggest that diabetes resistance genes in Idd13 and Idd9/11, and BCL2L1, IL6-AR and IFNG-IRF-1-IFN-I/IRF-7-IL12 pathways play an important role in CD4 T-cells in the early pathogenesis of autoimmune diabetes. Thus, the alternative approach of investigation at the molecular systems level has captured new information, which combined with validation studies, offers the opportunity to test hypotheses on the role played by the genes/molecular pathways identified in this study, to understand better the mechanisms of autoimmune diabetes in CD4 T-cells, and to develop new therapeutic strategies for the disease.

Project description:Aims/hypothesis AGEs are considered environmental contributors of type 1 diabetes, but the exact role AGEs play early in pathogenesis of the disease, remains unidentified. We aimed to reduce AGEs with the pharmacotherapy alagebrium chloride in MIN6N8 cells and early in life in NOD mice to determine its impact on beta cell immunogenicity, function, and disease progression. Methods MIN6N8 cells were cultured with AGEs with or without short-term alagebrium therapy to determine the effect on ER stress and beta cell antigen presentation via a reporter assay for protein responses in the unfolded protein response, the enzymatic activity of endoplasmic reticulum aminopeptidase-1 (ERAP1) and the immunopeptidome. To determine the effect of short-term alagebrium therapy on beta cells in vivo, female NOD mice were treated with alagebrium and insulin secretion, insulitis, and immune cell repertoire were studied. Adoptive transfer studies and diabetes progression studies were used to consider the impact of alagebrium on immune cell function and disease outcome. Results In MIN6N8 cells, alagebrium therapy inhibited the induction of endoplasmic reticulum (ER) stress and the activity of ERAP1 by AGE-modified proteins. Alagebrium treated-MIN6N8 cells did not change the MHC Class I presentation of known beta cell antigens but did induce proteomic changes related to ER homeostatic pathways. Prior to overt autoimmune diabetes, female NOD mice treated with alagebrium for 30-40 days had improved insulin secretion, reduced insulitis and amplified proportions of pancreatic CD8+ T cells, mature B cells and F4/80+ macrophages. Splenocytes from alagebrium-treated mice adoptively transferred disease to NODscid recipients and maintained interferon production in vitro. While partial protection of islets by alagebrium was seen following the adoptive transfer of activated NOD G9C8 transgenic TCR CD8+ T cells, alagebrium therapy in NOD mice did not reduce diabetes progression. Conclusions/interpretation Our data suggests that in experimental models of diabetes, short-term alagebrium treatment allows for beta cell improvement, and maintenance of immune cell function, which does not fully mitigate diabetes progression.

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Molecular Phenotyping of Immune Cells from Young NOD Mice

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