IL-15 augments TCR-induced CD4⁺ T cell expansion in vitro by inhibiting the suppressive function of CD25High CD4⁺ T cells

Due to its critical role in NK cell differentiation and CD8(+) T cell homeostasis, the importance of IL-15 is more firmly established for cytolytic effectors of the immune system than for CD4(+) T cells. The increased levels of IL-15 found in several CD4(+) T cell-driven (auto-) immune diseases prompted us to examine how IL-15 influences murine CD4(+) T cell responses to low dose TCR-stimulation in vitro. We show that IL-15 exerts growth factor activity on both CD4(+) and CD8+ T cells in a TCR-dependent and Cyclosporin A-sensitive manner. In CD4(+) T cells, IL-15 augmented initial IL-2-dependent expansion and once IL-15R alpha was upregulated, IL-15 sustained the TCR-induced expression of IL-2/15R beta, supporting proliferation independently of secreted IL-2. Moreover, IL-15 counteracts CD4(+) T cell suppression by a gradually expanding CD25(High)CD4(+) T cell subset that expresses Foxp3 and originates from CD4(+)CD25(+) Tregs. These in vitro data suggest that IL-15 may dramatically strengthen the T cell response to suboptimal TCR-triggering by overcoming an activation threshold set by Treg that might create a risk for autoimmune pathology

Conserved structured domains in plant non-coding RNA enod40, their evolution and recruitment of sequences from transposable elements

Plant long noncoding RNA enod40 is involved in the regulation of symbiotic associations with bacteria, in particular, in nitrogen-fixing root nodules of legumes, and with fungi in phosphate-acquiring arbuscular mycorrhizae formed by various plants. The presence of enod40 genes in plants that do not form such symbioses indicates its other roles in cell physiology. The molecular mechanisms of enod40 RNA function are poorly understood. Enod40 RNAs form several structured domains, conserved to different extents. Due to relatively low sequence similarity, identification of enod40 sequences in plant genomes is not straightforward, and many enod40 genes remain unannotated even in complete genomes. Here, we used comparative structure analysis and sequence similarity searches in order to locate enod40 genes and determine enod40 RNA structures in nitrogen-fixing clade plants and in grasses. The structures combine conserved features with considerable diversity of structural elements, including insertions of structured domain modules originating from transposable elements. Remarkably, these insertions contain sequences similar to tandem repeats and several stem-loops are homologous to microRNA precursors.</p

1,25-Dihydroxyvitamin D-3 and its analog TX527 promote a stable regulatory T cell phenotype in T cells from type 1 diabetes patients

The emergence of regulatory T cells (Tregs) as central mediators of peripheral tolerance in the immune system has led to an important area of clinical investigation to target these cells for the treatment of autoimmune diseases such as type 1 diabetes. We have demonstrated earlier that in vitro treatment of T cells from healthy individuals with TX527, a low-calcemic analog of bioactive vitamin D, can promote a CD4(+)CD25(high)CD127(low) regulatory profile and imprint a migratory signature specific for homing to sites of inflammation. Towards clinical application of vitamin D-induced Tregs in autologous adoptive immunotherapy for type 1 diabetes, we show here that 1,25-dihydroxyvitamin D-3 [1,25(OH)(2)D-3] and TX527 similarly imprint T cells from type 1 diabetes patients with a CD4(+)CD25(high)CD127(low) regulatory profile, modulate surface expression of skin- and inflammation-homing receptors, and increase expression of CTLA-4 and OX-40. Also, 1,25(OH)(2)D-3 and TX527 treatment inhibit the production of effector cytokines IFN-gamma, IL-9, and IL-17. Importantly, 1,25(OH)(2)D-3 and TX527 promote the induction of IL-10-producing CD4(+)CD25(high)CD127(low) T cells with a stable phenotype and the functional capacity to suppress proliferation of autologous responder T cells in vitro. These findings warrant additional validation of vitamin D-induced Tregs in view of future autologous adoptive immunotherapy in type 1 diabetes

IL-15 augments TCR-Induced CD4+ T Cell Expansion In Vitro by Inhibiting the Suppressive Function of CD25High CD4+ T Cells

Due to its critical role in NK cell differentiation and CD8+ T cell homeostasis, the importance of IL-15 is more firmly established for cytolytic effectors of the immune system than for CD4+ T cells. The increased levels of IL-15 found in several CD4+ T cell-driven (auto-) immune diseases prompted us to examine how IL-15 influences murine CD4+ T cell responses to low dose TCR-stimulation in vitro. We show that IL-15 exerts growth factor activity on both CD4+ and CD8+ T cells in a TCR-dependent and Cyclosporin A-sensitive manner. In CD4+ T cells, IL-15 augmented initial IL-2-dependent expansion and once IL-15Rα was upregulated, IL-15 sustained the TCR-induced expression of IL-2/15Rβ, supporting proliferation independently of secreted IL-2. Moreover, IL-15 counteracts CD4+ T cell suppression by a gradually expanding CD25HighCD4+ T cell subset that expresses Foxp3 and originates from CD4+CD25+ Tregs. These in vitro data suggest that IL-15 may dramatically strengthen the T cell response to suboptimal TCR-triggering by overcoming an activation threshold set by Treg that might create a risk for autoimmune pathology

Interleukin-21 Is Required for the Development of Type 1 Diabetes in NOD Mice

OBJECTIVE: Interleukin (IL)-21 is a type 1 cytokine that has been implicated in the pathogenesis of type 1 diabetes via the unique biology of the nonobese diabetic (NOD) mouse strain. The aim of this study was to investigate a causal role for IL-21 in type 1 diabetes. RESEARCH DESIGN AND METHODS: We generated IL-21R–deficient NOD mice and C57Bl/6 mice expressing IL-21 in pancreatic β-cells, allowing the determination of the role of insufficient and excessive IL-21 signaling in type 1 diabetes. RESULTS: Deficiency in IL-21R expression renders NOD mice resistant to insulitis, production of insulin autoantibodies, and onset of type 1 diabetes. The lymphoid compartment in IL-21R−/− NOD is normal and does not contain an increased regulatory T-cell fraction or diminished effector cytokine responses. However, we observed a clear defect in autoreactive effector T-cells in IL-21R−/− NOD by transfer experiments. Conversely, overexpression of IL-21 in pancreatic β-cells induced inflammatory cytokine and chemokines, including IL-17A, IL17F, IFN-γ, monocyte chemoattractant protein (MCP)-1, MCP-2, and interferon-inducible protein-10 in the pancreas. The ensuing leukocytic infiltration in the islets resulted in destruction of β-cells and spontaneous type 1 diabetes in the normally diabetes-resistant C57Bl/6 and NOD × C57Bl/6 backgrounds. CONCLUSIONS: This work provides demonstration of the essential prodiabetogenic activities of IL-21 on diverse genetic backgrounds (NOD and C57BL/6) and indicates that IL-21 blockade could be a promising strategy for interventions in human type 1 diabetes

dietary supplementation with high doses of regular vitamin d3 safely reduces diabetes incidence in nod mice when given early and long term

High doses of the active form of vitamin D3, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) prevent diabetes in the non-obese diabetic (NOD) mouse but also elicit unwanted calcemic side-effects. Because immune cells themselves can convert vitamin D3 into 1,25(OH)2D3 locally, we hypothesized that dietary vitamin D3 can also prevent disease. Thus, we evaluated whether dietary administration of high doses of regular vitamin D3 (800 IU per day) during different periods of life (pregnancy and lactation, early-life (3-14 weeks of age), or lifelong (3-35 weeks of age)) safely prevents diabetes in NOD mice. We found that only lifelong treatment raised serum 25-hydroxyvitamin D3 from 173 nmol/L in controls to 290 nmol/L, without inducing signs of calcemic or bone toxicity, and significantly reduced diabetes development in both male and female NOD mice. This diabetes protection by vitamin D3 correlated with preserved pancreatic insulin content and improved insulitis scores. Moreover, vitamin D3 treatment decreased interferon-γ-positive CD8+ T-cells and increased CD4+(CD25+)FoxP3+ T-cells in pancreatic draining lymph nodes. In conclusion, this study shows for the first time that high doses of regular dietary vitamin D3 can safely prevent diabetes in NOD mice when administered lifelong, although caution is warranted with regards to administering equivalently high doses in humans

A Mathematical Model for Interpretable Clinical Decision Support with Applications in Gynecology

Over time, methods for the development of clinical decision support (CDS) systems have evolved from interpretable and easy-to-use scoring systems to very complex and non-interpretable mathematical models. In order to accomplish effective decision support, CDS systems should provide information on how the model arrives at a certain decision. To address the issue of incompatibility between performance, interpretability and applicability of CDS systems, this paper proposes an innovative model structure, automatically leading to interpretable and easily applicable models. The resulting models can be used to guide clinicians when deciding upon the appropriate treatment, estimating patient-specific risks and to improve communication with patients.We propose the interval coded scoring (ICS) system, which imposes that the effect of each variable on the estimated risk is constant within consecutive intervals. The number and position of the intervals are automatically obtained by solving an optimization problem, which additionally performs variable selection. The resulting model can be visualised by means of appealing scoring tables and color bars. ICS models can be used within software packages, in smartphone applications, or on paper, which is particularly useful for bedside medicine and home-monitoring. The ICS approach is illustrated on two gynecological problems: diagnosis of malignancy of ovarian tumors using a dataset containing 3,511 patients, and prediction of first trimester viability of pregnancies using a dataset of 1,435 women. Comparison of the performance of the ICS approach with a range of prediction models proposed in the literature illustrates the ability of ICS to combine optimal performance with the interpretability of simple scoring systems.The ICS approach can improve patient-clinician communication and will provide additional insights in the importance and influence of available variables. Future challenges include extensions of the proposed methodology towards automated detection of interaction effects, multi-class decision support systems, prognosis and high-dimensional data

Access to primary care for socio-economically disadvantaged older people in rural areas: exploring realist theory using structural equation modelling in a linked dataset

Background: Realist approaches seek to answer questions such as ‘how?’, ‘why?’, ‘for whom?’, ‘in what circumstances?’ and ‘to what extent?’ interventions ‘work’ using context-mechanism-outcome (CMO) configurations. Quantitative methods are not well-established in realist approaches, but structural equation modelling (SEM) may be useful to explore CMO configurations. Our aim was to assess the feasibility and appropriateness of SEM to explore CMO configurations and, if appropriate, make recommendations based on our access to primary care research. Our specific objectives were to map variables from two large population datasets to CMO configurations from our realist review looking at access to primary care, generate latent variables where needed, and use SEM to quantitatively test the CMO configurations. Methods: A linked dataset was created by merging individual patient data from the English Longitudinal Study of Ageing and practice data from the GP Patient Survey. Patients registered in rural practices and who were in the highest deprivation tertile were included. Three latent variables were defined using confirmatory factor analysis. SEM was used to explore the nine full CMOs. All models were estimated using robust maximum likelihoods and accounted for clustering at practice level. Ordinal variables were treated as continuous to ensure convergence. Results: We successfully explored our CMO configurations, but analysis was limited because of data availability. Two hundred seventy-six participants were included. We found a statistically significant direct (context to outcome) or indirect effect (context to outcome via mechanism) for two of nine CMOs. The strongest association was between ‘ease of getting through to the surgery’ and ‘being able to get an appointment’ with an indirect mediated effect through convenience (proportion of the indirect effect of the total was 21%). Healthcare experience was not directly associated with getting an appointment, but there was a statistically significant indirect effect through convenience (53% mediated effect). Model fit indices showed adequate fit. Conclusions: SEM allowed quantification of CMO configurations and could complement other qualitative and quantitative techniques in realist evaluations to support inferences about strengths of relationships. Future research exploring CMO configurations with SEM should aim to collect, preferably continuous, primary data