Assessing the role of microRNAs in post-transcriptional control of thymocytes and peripheral lymphocytes in NOD mice
Ontology highlight
ABSTRACT: As early as one month of age, non-obese diabetic (NOD) mice feature pancreatic infiltration of autoreactive T lymphocytes, which destruct insulin-producing beta cells, leading to autoimmune diabetes mellitus (T1D) within eight months. Thus, we hypothesized that during the development of T1D, the transcriptional modulation of immune reactivity genes, as well as, modulation of microRNAs (miRNAs) may occur during thymocytes mature into peripheral CD3+ T lymphocytes. Our aim is to analyze the transcriptional modulation of mRNA and microRNAs during development of thymocytes into peripheral CD3+ T lymphocytes in the context of the emergence of T1D.
Project description:Non-obese diabetic (NOD) mice feature pancreatic infiltration of autoreactive T lymphocytes as early as 1 month of age, which destruct insulin-producing beta-cells to finally emerge autoimmune diabetes mellitus (T1D) within 8 months. In view, we hypothesized that during the development of T1D, transcriptional modulation of immune reactivity genes may occur as thymocytes mature toward peripheral T lymphocytes. Transcriptome of thymocytes and peripheral CD3+ T lymphocytes from pre-diabetic or diabetic mice analyzed through microarray hybridizations allowed observation of 3,586 differentially expressed genes. Hierarchical clustering grouped mice according to age/T1D onset and genes to their ontology. Transcriptional activity of thymocytes toward peripheral T lymphocytes unraveled sequential participation of genes involved with CD4+/CD8+ T cell differentiation (Themis), tolerance induction (Foxp3), apoptosis (Fasl) to soon after T cell activation (IL4), while the emergence of T1D coincided with the expression of cytotoxicity (Crtam) and inflammatory response genes (Tlr) by peripheral T lymphocytes.
Project description:As early as one month of age, nonobese diabetic (NOD) mice feature pancreatic infiltration of autoreactive T lymphocytes, which destruct insulin-producing beta cells, producing autoimmune diabetes mellitus (T1D) within eightmonths. Thus, we hypothesized that during the development of T1D, the transcriptional modulation of immune reactivity genes may occur as thymocytes mature into peripheral T lymphocytes. The transcriptome of thymocytes and peripheral CD3+ T lymphocytes from prediabetic or diabetic mice analyzed through microarray hybridizations identified the differentially expressed genes.
Project description:As early as one month of age, nonobese diabetic (NOD) mice feature pancreatic infiltration of autoreactive T lymphocytes, which destruct insulin-producing beta cells, producing autoimmune diabetesmellitus (T1D) within eight months. Thus, we hypothesized that during the development of T1D, the transcriptional modulation of immune reactivity genes may occur as thymocytes mature into peripheral T lymphocytes. The transcriptome of thymocytes and peripheral CD3+ T lymphocytes from prediabetic or diabetic mice analyzed through microarray hybridizations identified the differentially expressed genes.
Project description:Phenotypic plasticity, the ability of one genotype to express different phenotypes in response to changing environmental conditions, is one of the most common phenomena characterising the living world and is not only relevant for the ecology but also for the evolution of species. Daphnia, the waterflea, is a textbook example for predator induced phenotypic plastic defences including changes in life-history, behaviour and morphology. However, the analysis of molecular mechanisms underlying these inducible defences is still in its early stages.<br><br>We exposed Daphnia magna to chemical cues of the predator Triops cancriformis to identify key processes underlying plastic defensive trait formation. D. magna is known to develop an array of morphological changes in the presence of T. cancriformis including changes of carapace morphology and cuticle hardening. To get a more comprehensive idea of this phenomenon, we studied four different genotypes originating from habitats with different predation history, reaching from predator-free to temporary habitats containing T. cancriformis.<br><br>We analysed the morphologies as well as proteomes of predator-exposed and control animals. Three genotypes showed morphological changes when the predator was present. Using a high-throughput proteomics approach, we found 294 proteins which were significantly altered in their abundance after predator exposure in a general or genotype dependant manner. Proteins connected to genotype dependant responses were related to the cuticle, protein synthesis and calcium binding whereas the yolk protein vitellogenin increased in abundance in all genotypes, indicating their involvement in a more general response. Furthermore, genotype dependant responses at the proteome level correlated well with local adaptation to Triops predation.<br><br>Altogether, our study provides new insights concerning genotype dependant and general molecular processes involved in predator-induced phenotypic plasticity in D. magna.
Project description:The tolerogenic anti-CD3 monoclonal antibodies (anti-CD3) are promising compounds for the treatment of type 1 diabetes (T1D). Anti-CD3 administration induces transient T-cell depletion both in preclinical and in clinical studies. Notably, said depletion mainly affects CD4+ but not CD8+ T cells. Moreover, T1D reversal in preclinical models is accompanied by the selective expansion of CD4+FOXP3+ T regulatory (Treg) cells, which are fundamental for the long-term maintenance of anti-CD3-mediated tolerance. The mechanisms that lead to this immune-shaping by affecting mainly CD4+ T effector cells while sparing CD4+FOXP3+ Treg cells have still to be fully elucidated. This study shows that CD3 expression levels differ from one T-cell subset to another. CD4+FOXP3- T cells contain higher amounts of CD3 molecules than do CD4+FOXP3+ and CD8+ T cells both in mice and in humans. Said differences may explain the anti-CD3-mediated immune resetting that occurs in vivo after anti-CD3 administration in mice. In addition, transcriptome analysis demonstrates that CD4+FoxP3+ Treg cells are significantly less responsive than CD4+FoxP3- T cells to anti-CD3 treatment at molecular levels. Thus, heterogeneity in CD3 expression likely confers the various T-cell subsets differing susceptibility to in vivo tolerogenic anti-CD3-mediated modulation. This data sheds new light on the molecular mechanism that underlies anti-CD3-mediated immune resetting, and thus may open new opportunities to improve this promising treatment.
Project description:To define the physiological properties of TCR signaling, We investigated the global dynamic view of TCR-dependent phosphorylation with the use of thymocytes stimulated with antibodies to CD3 to mimic TCR activation
Project description:Glucocorticoids induce rapid apoptosis of rat primary thymocytes through mechanisms requiring altered gene expression. The determination of genes regulating glucocorticoid-induced apoptosis of lymphocytes has received considerable attention. However, the role of specific non-coding microRNAs in the regulation of glucocorticoid-induced apoptosis of lymphocytes is poorly defined. Using deep sequencing analysis, we have identified microRNAs differentially expressed during glucocorticoid-induced apoptosis of rat primary thymocytes. We have also identified numerous loci that harbor probable novel microRNAs. Furthermore, we have validated the glucocorticoid-responsive expression of 2 novel microRNAs in the apoptotic rat primary thymocyte. These 2 novel microRNAs are predicted to target numerous messenger RNAs throughout the genome. Using whole genome expression analysis, we now seek to correlate the altered expression of these novel microRNAs with the expression of their predicted target mRNAs during glucocorticoid-induced apoptosis.
Project description:Insulin-dependent diabetes mellitus (T1D) is an organ-specific auto-immune disease caused by the selective destruction of the pancreatic beta cells by inflammatory cells, especially auto-reactive CD8+ T lymphocytes. In this study we evaluated the differential large scale gene expression profiling using cDNA microarrays of T (CD4+ and CD8+) and monocyte (CD14+) cells. In addition, considering that HLA class II profile may influence the expression of these molecules on the surface of peripheral blood cells, and considering that the mechanisms by which HLA class II susceptibility alleles drive the auto-immune response have not been elucidated, we intend to further stratify T1D patients according to the HLA class II profile. 20 pre-pubertal recently diagnosed T1D patients were selected, HLA-DRB1/DQB1 allele typing and separated in two groups. The group 1(G1) had patients with susceptibility alleles and group 2 (G2) with at least one protection allele. To established relationships between genes, the GeneNetwork 1.2 algorithm was used, 6 networks were obtained, TCD4+ G1 patients X controls, TCD4+ G2 patients X controls, and same situation to TCD8+ and CD14+.
Project description:Type 1 diabetes (T1D) results from autoimmune destruction of β cells in the pancreas. Protein tyrosine phosphatases (PTPs) are candidate genes for T1D and play a key role in autoimmune disease development and β-cell function. Here, we assessed the global protein and individual PTP profile in the pancreas of diabetic NOD mice treated with anti-CD3 mAb and IL-1RA combination therapy. The treatment reversed hyperglycemia compared to the anti-CD3 alone control group. We observed enhanced expression of PTPN2, a T1D candidate gene, and endoplasmic reticulum (ER) chaperones in the islets from cured mice.
Project description:Glucocorticoids induce rapid apoptosis of rat primary thymocytes through mechanisms requiring altered gene expression. The determination of genes regulating glucocorticoid-induced apoptosis of lymphocytes has received considerable attention. However, the role of specific non-coding microRNAs in the regulation of glucocorticoid-induced apoptosis of lymphocytes is poorly defined. Using deep sequencing analysis, we have identified microRNAs differentially expressed during glucocorticoid-induced apoptosis of rat primary thymocytes. We have also identified numerous loci that harbor probable novel microRNAs. Furthermore, we have validated the glucocorticoid-responsive expression of 2 novel microRNAs in the apoptotic rat primary thymocyte. These 2 novel microRNAs are predicted to target numerous messenger RNAs throughout the genome. Using whole genome expression analysis, we now seek to correlate the altered expression of these novel microRNAs with the expression of their predicted target mRNAs during glucocorticoid-induced apoptosis. Changes in gene expression during glucocorticoid-induced apoptosis of rat primary thymocyes (3 biological replicates) were measured after 6 hours of 100nM dexamethasone treatment in-vitro.