Project description:Analyze the effect of TLR9 deficiency on immue cell function at the gene expression level. Our hypothesis was that TLR9 deficiency promotes CD73 expression in T cells thus regulates autoimmune diabetes development in NOD mice. Sorted TCRb+ cells were pooled from several mice for furhter RNA extraction and cRNA labeling.
Project description:Analyze the effect of TLR9 deficiency on immue cell function at the gene expression level. Our hypothesis was that TLR9 deficiency promotes CD73 expression in T cells thus regulates autoimmune diabetes development in NOD mice.
Project description:Appropriate tuning of protein homeostasis through mobilization of the unfolded protein response (UPR) is key to the capacity of pancreatic beta cells to cope with highly variable demand for insulin synthesis. An efficient UPR ensures a sufficient beta cell mass and secretory output but can also affect beta cell resilience to autoimmune aggression. However, the factors regulating protein homeostasis in the face of metabolic and immune challenges are insufficie tly understood. We examined beta cell adaptation to stress in mice deficient for insulin-degrading enzyme (IDE), a ubiquitous protease with high affinity for insulin, a putative ill-defined role in protein homeostasis, and genetic association with type 2 diabetes. IDE deficiency induces a low-level UPR in both standard and autoimmune non-obese diabetic (NOD) mice, associated with rapamycin-sensitive beta cell proliferation, as well as protection from diabetes in NOD mice. Moreover, in NOD islets, IDE deficiency specifically induces strong upregulation of regenerating islet-derived protein 2, a protein attenuating inflammation and protecting from autoimmunity. Our findings establish a role of IDE in islet cell protein homeostasis, corroborate the link between low-level UPR and proliferation, and identify an anti-inflammatory islet cell response uncovered in the absence of IDE of potential interest in autoimmune diabetes.
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
Project description:We collected whole genome testis expression data from hybrid zone mice. We integrated GWAS mapping of testis expression traits and low testis weight to gain insight into the genetic basis of hybrid male sterility.
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.
Project description:This a model from the article:
Modelling the onset of Type 1 diabetes: can impaired macrophage phagocytosis make the difference between health and disease?
Maree AF, Kublik R, Finegood DT, Edelstein-Keshet L.Philos Transact A Math Phys Eng Sci.2006 May 15;364(1842):1267-82.
16608707,
Abstract:
A wave of apoptosis (programmed cell death) occurs normally in pancreatic beta-cells of newborn mice. We previously showed that macrophages from non-obese diabetic (NOD) mice become activated more slowly and engulf apoptotic cells at a lower rate than macrophages from control (Balb/c) mice. It has been hypothesized that this low clearance could result in secondary necrosis, escalating inflammation and self-antigen presentation that later triggers autoimmune, Type 1 diabetes (T1D). We here investigate whether this hypothesis could offer a reasonable and parsimonious explanation for onset of T1D in NOD mice. We quantify variants of the Copenhagen model (Freiesleben De Blasio et al. 1999 Diabetes 48, 1677), based on parameters from NOD and Balb/c experimental data. We show that the original Copenhagen model fails to explain observed phenomena within a reasonable range of parameter values, predicting an unrealistic all-or-none disease occurrence for both strains. However, if we take into account that, in general, activated macrophages produce harmful cytokines only when engulfing necrotic (but not apoptotic) cells, then the revised model becomes qualitatively and quantitatively reasonable. Further, we show that known differences between NOD and Balb/c mouse macrophage kinetics are large enough to account for the fact that an apoptotic wave can trigger escalating inflammatory response in NOD, but not Balb/c mice. In Balb/c mice, macrophages clear the apoptotic wave so efficiently, that chronic inflammation is prevented.
This model originates from BioModels Database: A Database of Annotated Published Models (http://www.ebi.ac.uk/biomodels/). It is copyright (c) 2005-2011 The BioModels.net Team.
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To cite BioModels Database, please use: Li C, Donizelli M, Rodriguez N, Dharuri H, Endler L, Chelliah V, Li L, He E, Henry A, Stefan MI, Snoep JL, Hucka M, Le Novère N, Laibe C (2010) BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models. BMC Syst Biol., 4:92.
Project description:Nonobese diabetic (NOD) mice congenic for B10 derived genes in the Idd9 region of chromosome 4 are highly protected from the development of diabetes. In order to identify possible candidate genes within the Idd9 susceptibility region and possible downstream mediators of protection, we compared gene expression between NOD and Idd9 CD4+ T-cells. CD4+ T-cells with an activated phenotype (CD44-high/CD62L-low) were sorted from the pancreatic lymph nodes of female 8-week old mice. Mice were bred at Taconic farms and were line 905 (NOD.B10-Idd9 congenic) and line 6359 (NOD-like control strain with a B10 congenic region on chromosome 1 which does not modify diabetes incidence). Three replicate samples were prepared, each from four pooled pancreatic lymph nodes. CD4+CD44-highCD62L-low T-cells were sorted from each sample.