The Cytotoxic T Lymphocyte Antigen-4+49A/G Single Nucleotide Polymorphism Association With Visceral Leishmaniasis

Background: Several lines of evidence approve that innate and adaptive immunity play key roles in the defense against visceral leishmaniasis (VL). The polymorphism within the cytotoxic T lymphocyte antigen 4 (CTLA-4) gene alters its expression. Objectives: The main aim of this study was to evaluate the polymorphism within the +49 position of the CTLA-4 gene of Iranian patients with VL in comparison with healthy controls. Materials and Methods: In this cross-sectional study, 88 patients with clinical presentations of VL, who were seropositive for Leishmania (group 1), 86 patients without clinical presentations but seropositive (group 2), and 115 healthy controls (group 3) were assessed with respect to the CTLA-4 +49A/G polymorphism, using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The anti-Leishmania antibody titration was evaluated using an immunofluorescence method. Results: Our results indicated that both CTLA-4 +49A/G polymorphisms were significantly associated with VL. Conclusions: According to the results, the polymorphisms within the +49 position of CTLA-4 can be associated with VL and may be considered as risk factors for the disease

Hidden reach of the micromanagers

Small interfering RNAs can trigger unintended, microRNA-like off-target effects, but the impact of these effects on functional studies has been controversial. A recent study in BMC Genomics shows that microRNA-like effects can predominate among the 'hits' of functional genomics screens

Induction of microRNAs, mir-155, mir-222, mir-424 and mir-503, promotes monocytic differentiation through combinatorial regulation

Acute myeloid leukemia (AML) involves a block in terminal differentiation of the myeloid lineage and uncontrolled proliferation of a progenitor state. Using phorbol myristate acetate (PMA), it is possible to overcome this block in THP-1 cells (an M5-AML containing the MLL-MLLT3 fusion), resulting in differentiation to an adherent monocytic phenotype. As part of FANTOM4, we used microarrays to identify 23 microRNAs that are regulated by PMA. We identify four PMA-induced micro- RNAs (mir-155, mir-222, mir-424 and mir-503) that when overexpressed cause cell-cycle arrest and partial differentiation and when used in combination induce additional changes not seen by any individual microRNA. We further characterize these prodifferentiative microRNAs and show that mir-155 and mir-222 induce G2 arrest and apoptosis, respectively. We find mir-424 and mir-503 are derived from a polycistronic precursor mir-424-503 that is under repression by the MLL-MLLT3 leukemogenic fusion. Both of these microRNAs directly target cell-cycle regulators and induce G1 cell-cycle arrest when overexpressed in THP-1. We also find that the pro-differentiative mir-424 and mir-503 downregulate the anti-differentiative mir-9 by targeting a site in its primary transcript. Our study highlights the combinatorial effects of multiple microRNAs within cellular systems.Comment: 45 pages 5 figure

MiR-107 and MiR-185 Can Induce Cell Cycle Arrest in Human Non Small Cell Lung Cancer Cell Lines

Background: MicroRNAs (miRNAs) are short single stranded noncoding RNAs that suppress gene expression through either translational repression or degradation of target mRNAs. The annealing between messenger RNAs and 5' seed region of miRNAs is believed to be essential for the specific suppression of target gene expression. One miRNA can have several hundred different targets in a cell. Rapidly accumulating evidence suggests that many miRNAs are involved in cell cycle regulation and consequentially play critical roles in carcinogenesis. Methodology/Principal Findings: Introduction of synthetic miR-107 or miR-185 suppressed growth of the human non-small cell lung cancer cell lines. Flow cytometry analysis revealed these miRNAs induce a G1 cell cycle arrest in H1299 cells and the suppression of cell cycle progression is stronger than that by Let-7 miRNA. By the gene expression analyses with oligonucleotide microarrays, we find hundreds of genes are affected by transfection of these miRNAs. Using miRNA-target prediction analyses and the array data, we listed up a set of likely targets of miR-107 and miR-185 for G1 cell cycle arrest and validate a subset of them using real-time RT-PCR and immunoblotting for CDK6. Conclusions/Significance: We identified new cell cycle regulating miRNAs, miR-107 and miR-185, localized in frequently altered chromosomal regions in human lung cancers. Especially for miR-107, a large number of down-regulated genes are annotated with the gene ontology term 'cell cycle'. Our results suggest that these miRNAs may contribute to regulate cell cycle in human malignant tumors.Full Tex

Genome-wide association studies of autoimmune vitiligo identify 23 new risk loci and highlight key pathways and regulatory variants

Vitiligo is an autoimmune disease in which depigmented skin results from the destruction of melanocytes1, with epidemiological association with other autoimmune diseases2. In previous linkage and genome-wide association studies (GWAS1 and GWAS2), we identified 27 vitiligo susceptibility loci in patients of European ancestry. We carried out a third GWAS (GWAS3) in European-ancestry subjects, with augmented GWAS1 and GWAS2 controls, genome-wide imputation, and meta-analysis of all three GWAS, followed by an independent replication. The combined analyses, with 4,680 cases and 39,586 controls, identified 23 new significantly associated loci and 7 suggestive loci. Most encode immune and apoptotic regulators, with some also associated with other autoimmune diseases, as well as several melanocyte regulators. Bioinformatic analyses indicate a predominance of causal regulatory variation, some of which corresponds to expression quantitative trait loci (eQTLs) at these loci. Together, the identified genes provide a framework for the genetic architecture and pathobiology of vitiligo, highlight relationships with other autoimmune diseases and melanoma, and offer potential targets for treatment

A composite immune signature parallels disease progression across T1D subjects

At diagnosis, most people with type 1 diabetes (T1D) produce measurable levels of endogenous insulin, but the rate at which insulin secretion declines is heterogeneous. To explain this heterogeneity, we sought to identify a composite signature predictive of insulin secretion, using a collaborative assay evaluation and analysis pipeline that incorporated multiple cellular and serum measures reflecting beta cell health and immune system activity. The ability to predict decline in insulin secretion would be useful for patient stratification for clinical trial enrollment or therapeutic selection. Analytes from 12 qualified assays were measured in shared samples from subjects newly diagnosed with T1D. We developed a computational tool to identify a composite panel associated with decline in insulin secretion over 2 years after diagnosis. The tool employs multiple filtering steps to reduce data dimensionality, incorporates error-estimation techniques including cross-validation and sensitivity analysis, and is flexible to assay type, clinical outcome and disease setting. Using this novel analytical tool, we identified a panel of immune markers that, in combination, are highly associated with loss of insulin secretion. The methods used here represent a novel process for identifying combined immune signatures that predict outcomes relevant for complex and heterogeneous diseases like T1D

CTLA-4 Activation of Phosphatidylinositol 3-Kinase (PI 3-K) and Protein Kinase B (PKB/AKT) Sustains T-Cell Anergy without Cell Death

The balance of T-cell proliferation, anergy and apoptosis is central to immune function. In this regard, co-receptor CTLA-4 is needed for the induction of anergy and tolerance. One central question concerns the mechanism by which CTLA-4 can induce T-cell non-responsiveness without a concurrent induction of antigen induced cell death (AICD). In this study, we show that CTLA-4 activation of the phosphatidylinositol 3-kinase (PI 3-K) and protein kinase B (PKB/AKT) sustains T-cell anergy without cell death. CTLA-4 ligation induced PI 3K activation as evidenced by the phosphorylation of PKB/AKT that in turn inactivated GSK-3. The level of activation was similar to that observed with CD28. CTLA-4 induced PI 3K and AKT activation also led to phosphorylation of the pro-apoptotic factor BAD as well as the up-regulation of BcL-XL. In keeping with this, CD3/CTLA-4 co-ligation prevented apoptosis under the same conditions where T-cell non-responsiveness was induced. This effect was PI 3K and PKB/AKT dependent since inhibition of these enzymes under conditions of anti-CD3/CTLA-4 co-ligation resulted in cell death. Our findings therefore define a mechanism by which CTLA-4 can induce anergy (and possibly peripheral tolerance) by preventing the induction of cell death

Predicting and controlling the reactivity of immune cell populations against cancer

Heterogeneous cell populations form an interconnected network that determine their collective output. One example of such a heterogeneous immune population is tumor-infiltrating lymphocytes (TILs), whose output can be measured in terms of its reactivity against tumors. While the degree of reactivity varies considerably between different TILs, ranging from null to a potent response, the underlying network that governs the reactivity is poorly understood. Here, we asked whether one can predict and even control this reactivity. To address this we measured the subpopulation compositions of 91 TILs surgically removed from 27 metastatic melanoma patients. Despite the large number of subpopulations compositions, we were able to computationally extract a simple set of subpopulation-based rules that accurately predict the degree of reactivity. This raised the conjecture of whether one could control reactivity of TILs by manipulating their subpopulation composition. Remarkably, by rationally enriching and depleting selected subsets of subpopulations, we were able to restore anti-tumor reactivity to nonreactive TILs. Altogether, this work describes a general framework for predicting and controlling the output of a cell mixture

Oestradiol enhances tumour regression induced by B7-1/IL-2 adenoviral gene transfer in a murine model of breast cancer

The majority of breast cancers are oestrogen dependent and although current treatment strategies have improved, approximately 50% of the patients will develop metastasis. New treatments that result in long-term systemic immunity are therefore being developed. We have previously shown that adenoviral gene transfer of B7-I/IL-2 to murine breast cancer induces a high rate of complete turnout regression and systemic immunity. Since oestrogens not only affect breast cancer but also have been shown to modulate immune function and secretion of immune-regulatory cytokines, we explored whether administration of oestradiol altered the immune response induced by an adenoviral vector expressing B7-I/IL-2. An oestrogen-dependent murine breast cancer tumour was used in ovariectomised mice, supplemented either oestradiol or placebo. We report the somewhat unexpected finding that intratumoral injection of adenovirus expressing B7-I/IL-2 induces complete turnout regression in 76% of oestradiol-supplemented mice, while only 18% of the tumours regressed in the oestrogen-depleted group. Cured mice in both groups exhibited a similar CTL response against the tumour antigen. However, intratumoral IFN-? levels, 2 days after B7-I/IL-2 injection, were significantly higher in mice treated with oestradiol compared to placebo. This may be one mechanism explaining the higher response rate of tumours in oestradiol-replenished mice.</p

Association between the Cytotoxic T-Lymphocyte Antigen 4 +49G > A polymorphism and cancer risk: a meta-analysis

<p>Abstract</p> <p>Background</p> <p>As a key gene in the immunosurveillance of cell malignancy, Cytotoxic T-lymphocyte antigen 4 (CTLA-4 is an important negative regulator of T cell activation and proliferation. The CTLA-4 +49G > A polymorphism is one of the most commonly studied polymorphisms in this gene due to its association with cancer risks, but previous results have been conflicting.</p> <p>Methods</p> <p>We preformed a meta-analysis using 22 eligible case-control studies (including 32 datasets) with a total of 11,273 patients and 13,179 controls to summarize the existing data on the association between the <it>CTLA-4 </it>+49G > A polymorphism and cancer risk.</p> <p>Results</p> <p>Compared with the common <it>CTLA-4 </it>+49G > A GG genotype, the carriers of variant genotypes (<it>CTLA-4 </it>+49 GC/CC) had a 1.24-fold elevated risk of cancer (95% CI = 1.18-1.32, <it>P </it>< 0.05) under the dominant genetic model, as estimated using a fixed effect model. The effect of the <it>CTLA-4 </it>+49G > A polymorphism was further evaluated using stratification analysis. In four breast cancer studies, patients with the variant genotypes had a significantly increased risk of breast cancer (OR = 1.31, 95% CI = 1.17-1.48, <it>P </it>< 0.00001). A similar result was found in three skin cancer studies (OR = 1.30, 95% CI = 1.10-1.52, <it>P </it>= 0.001). In 26 solid tumor studies, subjects with the variant genotypes had a significantly higher risk of developing solid tumors (OR = 1.25, 95% CI = 1.18-1.33, <it>P </it>< 0.00001) compared with the 6 non-solid tumor studies (OR = 1.08, 95% CI = 0.79-1.48, <it>P </it>= 0.62). Patients with variant genotypes had significantly increased risk of non-epithelial tumors and epithelial tumors, with ORs of 1.23 (95% CI = 1.14-1.32, <it>P </it>< 0.00001) and 1.29 (95% CI = 1.17-1.41, <it>P </it>< 0.00001), respectively. It was also demonstrated that the increased risk of cancer associated with <it>CTLA-4 </it>+49G > A variant genotypes was more pronounced in Caucasians (OR = 1.29, 95% CI = 1.13-1.47, <it>P </it>= 0.0002), Asians (OR = 1.23, 95% CI = 1.16-1.32, <it>P </it>< 0.00001) and Chinese (OR = 1.23, 95% CI = 1.15-1.31, <it>P </it>< 0.00001).</p> <p>Conclusion</p> <p>Our meta-analysis suggests that the <it>CTLA-4 </it>+49G > A polymorphism genotypes (GA + AA) might be associated with an increased risk of cancer, especially in Caucasians and Chinese.</p