scholarly journals Gene expression profiling reveals Nef induced deregulation of lipid metabolism in HIV-1 infected T cells

2016 ◽  
Vol 472 (1) ◽  
pp. 169-174 ◽  
Author(s):  
Surya Shrivastava ◽  
Jay Trivedi ◽  
Debashis Mitra
Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 506-506
Author(s):  
Joachim Weischenfeldt ◽  
Inge Damgaard ◽  
David Bryder ◽  
Claus Nerlov ◽  
Bo Porse

Abstract Nonsense-mediated mRNA decay (NMD) is a conserved cellular surveillance system that degrades mRNAs with premature termination codons (PTCs). PTC-containing transcripts can arise from faulty events such as erroneous mRNA processing events as well as mutations, and their translation may lead to the synthesis of deleterious proteins. In addition to serving as a genomic protection system, experiments in tissue culture cells have demonstrated that NMD regulates 5% of the normal mRNA pool suggesting that the NMD pathway may have a broader role in gene regulation. Finally, NMD has also been proposed to be important during lymphocyte development as a tool of riding the cells of transcripts resulting from unproductive re-arrangements events of T cell receptor and immunoglobulin genes. Although NMD has been studied extensively at the biochemical level, the actual role and importance of NMD in the mammalian organism has not been investigated. We therefore generated a conditional Upf2 knock-out mouse line (UPF2 being an essential NMD factor) which we crossed to different hematopoietic relevant Cre expressing lines. Full ablation of UPF2 (using the inducible Mx1-Cre deleter) led to complete loss of all nucleated cells in the bone marrow and death of the animals within 10 days. A similar phenotype was observed when Upf2fl/fl; Mx1Cre BM cells were transplanted into lethally irradiated WT recipients and induced with poly-IC, demonstrating the cell autonomous nature of the phenotype. Deletion of UPF2 in the myeloid lineage using the LysM-Cre deleter resulted in efficient ablation of UPF2 and the absence of NMD in reporter transfected bone marrow derived macrophages (BMDMs). However, the steady state levels of myeloid cells appeared unaltered. Finally, deletion of UPF2 in T cells using a Lck-Cre deleter led to a marked reduction of both CD4/CD8 double-positive and single-positive T cells and accumulation of PTC containing transcripts. Gene expression profiling experiments of BMDM and thymocytes from WT and UPF2-ablated animals identified a common core set of 27 up-regulated genes consistent with the role of NMD as a mRNA degrading system. The gene expression profiling data suggest that ablation of NMD leads to accumulation of unfolded proteins. In summary, these studies demonstrate the vital and cell-autonomous role of NMD in the hematopoietic system.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3068-3068
Author(s):  
Lindsay Nicholson ◽  
Emily Mavin ◽  
Lynne Minto ◽  
Julie Irving ◽  
Anne Dickinson ◽  
...  

Abstract Dendritic cells (DC) play a key role in the pathogenesis of Graft versus Host Disease (GvHD), a complication of haematopoietic stem cell transplantation and offer an attractive target for therapy. Regulatory T cells (Treg) have a potent immunoregulatory effect on the maturation and the antigen-presenting cell (APC) function of DC and adoptive transfer of Treg is highly efficacious in the induction of tolerance in an experimental model of GvHD and has entered Phase I clinical trials. Several mechanisms of suppression have been proposed, including Treg acting directly on DCs, attenuating their antigen-presenting and co-stimulatory functions by arresting their maturation. However, the molecular basis underpinning these effects in DCs remains ill-defined. We investigated the effect of Treg treatment on DCs by conducting gene expression profiling and confirmed the functional consequences using downstream assays. Immature, mature and Treg-treated DCs were generated from immuno-magnetic isolated monocytes (im-DC, mat-DC and Treg-DC, respectively) and moDC populations were generated using a well-established 6 day culture with GM-CSF and IL-4, followed by 24 hour LPS maturation. Treg were added on day 3 of culture at a 3:1 ratio. All cell populations were harvested on day 7 and sorted via FSC/SSC/CD3neg gating to remove Treg present in the co-culture and control for any changes in gene expression caused by shear stress. Gene expression profiling was carried out using the Illumina HumanHT12 microarray platform. Data was processed using R/Bioconductor workflows and the functional significance of differentially expressed genes was evaluated using Ingenuity Pathway Analysis software. Mat-DC and Treg-DC expression profiles were compared relative to the im-DC for data analysis. Upon LPS treatment, the levels of 1834 unique genes were differentially regulated in mat-DC by at least twofold (862 genes upregulated/972 downregulated) compared to the im-DC counterparts. In the Treg-DC, 1326 unique genes were differentially modulated (633 genes upregulated/693 genes downregulated). Microarray analysis of the CD markers identified a higher expression of the previously identified surface markers CD80, CD83 and CD86 in the mat-DC compared to the Treg-treated counterpart (validated by flow cytometry), confirming the semi-mature phenotype. Novel findings from the dataset include the reduction of the endocytotic-related genes, CD206 and CD209, in the Treg-DCs compared to the im-DC and this reduction manifested functionally in an impaired antigen uptake, as assessed by FITC-Dextran. Additionally, the surface marker, CD38, was downregulated in the Treg-DC compared to the mat-DC, confirmed by flow cytometry. CD38 has been shown to be NFκB-dependent and a marker of maturation in monocyte-derived DCs, further supporting the semi-mature phenotype. Furthermore, CD38 is functionally involved in CD83 expression and IL-12 induction. We assessed IL-12 cytokine secretion by Treg-treated DCs and showed a significantly reduced level of induction compared to mat-DC (p=0.0079). Pathway analysis revealed NFκB-related genes to be downregulated in the Treg-DC compared to the mat-DC. These differentially expressed genes included the TLR-adaptor protein, MYD88, the NFκB subunit, RELB and an inhibitor of NFκB, NFκB1A. This finding, coupled to the importance of NFκB signalling pathway in DC function, prompted us to investigate it at the functional level by measuring levels of phosphorylation of serine 536 of the RelA subunit as a marker of activity in response to LPS stimulation. DC cultured in the absence of Tregs (mat-DC) showed significantly higher levels of Ser536 phosphorylation when compared to those unstimulated cells (im-DC) (p= 0.0018). Concordant with the gene expression data, Treg-treated DCs (Treg-DC), showed a significantly attenuated NFκB activation when compared to their LPS-stimulated DCs counterparts (p = 0.0191), however, signalling was not completely abolished compared to those unstimulated DCs (p= 0.0003). In conclusion, gene expression profiles of Treg-treated DCs are significantly different to their mat-DC and im-DC counterparts. Here, we present the novel finding that Tregs modulate DC function, in part, by attenuation of the NFkB signalling pathway, arresting the DCs at a semi-mature phenotype, as evidenced by expression arrays and functional assays. Disclosures No relevant conflicts of interest to declare.


2011 ◽  
Vol 121 (10) ◽  
pp. 4170-4179 ◽  
Author(s):  
James C. Lee ◽  
Paul A. Lyons ◽  
Eoin F. McKinney ◽  
John M. Sowerby ◽  
Edward J. Carr ◽  
...  

Virology ◽  
2006 ◽  
Vol 352 (1) ◽  
pp. 86-99 ◽  
Author(s):  
Mayra Solis ◽  
Peter Wilkinson ◽  
Raphaelle Romieu ◽  
Eduardo Hernandez ◽  
Mark A. Wainberg ◽  
...  

PLoS ONE ◽  
2013 ◽  
Vol 8 (6) ◽  
pp. e64748 ◽  
Author(s):  
Luana Tatiana Albuquerque Guerreiro ◽  
Anna Beatriz Robottom-Ferreira ◽  
Marcelo Ribeiro-Alves ◽  
Thiago Gomes Toledo-Pinto ◽  
Tiana Rosa Brito ◽  
...  

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 5201-5201
Author(s):  
Chieh Lee Wong ◽  
Baoshan Ma ◽  
Gareth Gerrard ◽  
Martyna Adamowicz-Brice ◽  
Zainul Abidin Norziha ◽  
...  

Abstract Background The past decade has witnessed a significant progress in the understanding of the molecular pathogenesis of myeloproliferative neoplasms (MPN). A large number of genes have now been implicated in the pathogenesis of MPN but their relative importance, the mechanisms by which they cause different cell types to predominate and their implications for prognosis remain unknown. We hypothesized that there are other genes which may contribute to the pathogenesis of the different disease subtypes detectable only by cell-type specific analysis. Aim The aim of this study was to perform gene expression profiling on different cell types from patients with MPN in order to identify novel variants and driver mutations, to elucidate the pathogenesis and to identify predictors of survival in patients with MPN in a multiracial country. Methods We performed gene expression profiling on normal controls (NC) and patients with MPN from 3 different races (Malay, Chinese and Indian) in Malaysia who were diagnosed with essential thrombocythemia (ET), polycythemia vera (PV) and primary myelofibrosis (PMF) according to the 2008 WHO diagnostic criteria for MPN. Two cohorts of patients, the patient and validation cohorts, from 3 tertiary-level hospitals were recruited prospectively over 3 years and informed consents were obtained. Peripheral blood samples were taken and sorted into polymorphonuclear cells (PMNs), mononuclear cells (MNCs) and T cells. RNA was extracted from each cell population. Gene expression profiling was performed using the Illumina HumanHT-12 Expression Beadchip for microarray and the Illumina Nextera XT DNA Sample Preparation Kit for next generation sequencing on the patient and validation cohorts respectively. Results Twenty-eight patients (10 ET, 11 PV and 7 PMF) and 11 NC were recruited into the patient cohort. Twelve patients (4 ET, 4 PV and 4 PMF) and 4 NC were recruited into the validation cohort. Gene expression levels for each cell type in each disease were compared with NC. In the patient cohort, the number of differentially expressed genes in ET, PV and PMF was 0, 141 and 15 respectively for PMNs (p < 0.05 after multiple testing correction) and 5, 170 and 562 respectively for MNCs (p < 0.05). No differentially expressed genes were identified for T cells in any of the three disease groups. RNA-seq analysis of samples from the validation cohort was used to corroborate these findings. After combination, we were able to confirm differential expression of 0, 14 and 7 genes in ET, PV and PMF respectively for PMNs (p < 0.05) and 51 genes in only PMF for MNCs (p < 0.05). The validated differentially expressed genes for PMNs and MNCs were mutually exclusive except for one gene. The differentially expressed genes in PV and PMF for PMNs were involved in cellular processes and metabolic pathways whereas the differentially expressed genes for PMF in MNCs were involved in regulation of cytoskeleton, focal adhesion and cell signaling pathways. Conclusion This is the first study to use microarray and next generation sequencing techniques to compare cell type-specific expression of genes between different subtypes of MPN. The lack of differential expression in T cells validates the techniques used and indicates that they are not part of the neoplastic clone. Differential expression of genes for MNCs was seen only in PMF which may be related to their more severe phenotype. Interestingly, there were fewer differentially expressed genes in PMF compared to PV for PMNs. The lack of differential expression in ET may either reflect the relatively milder phenotype of the disease or that differential expression is limited to megakaryocytes-platelets which were not studied. The lists of mutually exclusive cell type-specific differentially expressed genes for PMNs and MNCs provide further insight into the pathogenesis of MPN and into the differences between its different forms. The identified genes also indicate further routes for investigation of pathogenesis and possible disease-specific targets for therapy. Disclosures Aitman: Illumina: Honoraria.


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