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ABSTRACT:
PROVIDER: PRJNA97645 | ENA |
REPOSITORIES: ENA
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Project description:DC-SIGN initiates an immature dendritic cell phenotype triggering Rho activation that is utilised by HIV-1
| PRJNA97645 | ENA
Project description:DC-SIGN is a C-type lectin expressed by dendritic cells (DCs) that binds HIV-1, sequestering it within multivesicular bodies to facilitate transmission to CD4+ T cells. Here we characterize the molecular basis of signalling through DC-SIGN by large-scale gene expression profiling and phosphoproteome analysis. Solitary DC-SIGN activation leads to a phenotypically disparate transcriptional program from Toll-like receptor (TLR) triggering with downregulation of MHC II, CD86, and interferon response genes and with induction of the TLR negative regulator ATF3. Phosphoproteome analysis reveals DC-SIGN signals through the leukemia-associated Rho guanine nucleotide exchange factor (LARG) to induce Rho activity. This LARG activation also occurs on DC HIV exposure and is required for effective HIV viral synapse formation. Taken together HIV mediated DC-SIGN signalling provides a mechanism by which HIV evades the immune response yet induces viral spread. Experiment Overall Design: Circulating monocyte derived DCs were isolated from buffy coats by adherence and culture in IL-4 and granulocyte-macrophage colony-stimulating factor (GM-CSF). DC preparations analyzed were more than 98% pure. At day four 10 million immature DCs were either left unstimulated or stimulated using plate bound anti-DC-SIGN antibody for 2 hr. Three replicates of non-stimulated or stimulated cells were taken and used to extract total RNA.
2008-06-14 | E-GEOD-6090 | biostudies-arrayexpress
Project description:DC-SIGN is a C-type lectin expressed by dendritic cells (DCs) that binds HIV-1, sequestering it within multivesicular bodies to facilitate transmission to CD4+ T cells. Here we characterize the molecular basis of signalling through DC-SIGN by large-scale gene expression profiling and phosphoproteome analysis. Solitary DC-SIGN activation leads to a phenotypically disparate transcriptional program from Toll-like receptor (TLR) triggering with downregulation of MHC II, CD86, and interferon response genes and with induction of the TLR negative regulator ATF3. Phosphoproteome analysis reveals DC-SIGN signals through the leukemia-associated Rho guanine nucleotide exchange factor (LARG) to induce Rho activity. This LARG activation also occurs on DC HIV exposure and is required for effective HIV viral synapse formation. Taken together HIV mediated DC-SIGN signalling provides a mechanism by which HIV evades the immune response yet induces viral spread. Keywords: Activation state, signalling, Toll-like Receptor (TLR)
2007-04-24 | GSE6090 | GEO
Project description:DC-SIGN+ monocyte-derived dendritic cells (mo-DCs) play important roles in bacterial infections and inflammatory diseases, but the factors regulating their differentiation and proinflammatory status remain poorly defined. Here, we identify a micro-RNA, miR-181a, and a molecular mechanism that simultaneously regulate the acquisition of DC-SIGN+ expression and the activation state of DC-SIGN+ mo-DCs. Specifically, we show that miR-181a promotes DC-SIGN expression during terminal mo-DC differentiation and limits its sensitivity and responsiveness to TLR triggering and CD40 ligation. Mechanistically, miR-181a sustains ERK-MAPK signaling in mo-DCs, thereby enabling the maintenance of high levels of DC-SIGN and a high activation threshold. Low miR-181a levels during mo-DC differentiation, induced by inflammatory signals, do not support the high phospho-ERK signal transduction required for DC-SIGNhi mo-DCs and lead to development of proinflammatory DC-SIGNlo/- mo-DCs. Collectively, our study demonstrates that high DC-SIGN expression levels and a high activation threshold in mo-DCs are linked and simultaneously maintained by miR-181a.
2020-03-10 | GSE96847 | GEO
Project description:Dendritic cells (DC) serve a key function in host defense, linking innate detection of microbes to the activation of pathogen-specific adaptive immune responses. Whether there is cell-intrinsic recognition of HIV-1 by host innate pattern-recognition receptors and subsequent coupling to antiviral T cell responses is not yet known. DC are largely resistant to infection with HIV-1, but facilitate infection of co-cultured T-helper cells through a process of trans-enhancement. We show here that, when DC resistance to infection is circumvented, HIV-1 induces DC maturation, an antiviral type I interferon response and activation of T cells. This innate response is dependent on the interaction of newly-synthesized HIV-1 capsid (CA) with cellular cyclophilin A (CypA) and the subsequent activation of the transcription factor IRF3. Because the peptidyl-prolyl isomerase CypA also interacts with CA to promote HIV-1 infectivity, our results suggest that CA conformation has evolved under opposing selective pressures for infectivity versus furtiveness. Thus, a cell intrinsic sensor for HIV-1 exists in DC and mediates an antiviral immune response, but it is not typically engaged due to absence of DC infection. The virulence of HIV-1 may be related to evasion of this response, whose manipulation may be necessary to generate an effective HIV-1 vaccine. We analyzed the gene expression profiles of uninfected human monocyte-derived dendritic cells (MDDCs) and MDDCs infected with an envelope-defective GFP-encoding VSV-G-pseudotyped HIV-1 vector (HIVGFP(G)) and with VSV-G pseudotyped virus-like particles derived from SIVmac to deliver Vpx (SIVVLP(G)), alone or in combination. Cells were infected at day 4 of differentiation and cells were harvested 48 hours later. RNA was extracted with TRIzol. RNA was labeled and hybridized to Human Genome U133A 2.0 arrays arrays following the Affymetrix protocols. Data were analyzed in R and Bioconductor.
2010-09-09 | E-GEOD-22589 | biostudies-arrayexpress
Project description:Cell division cycle 42 (Cdc42) is a member of the Rho GTPase family and has pivotal functions in actin organization, cell migration and proliferation. Cdc42 has been shown to regulate antigen (Ag)-uptake in immature dendritic cells (DC) and controls their migration from tissues to lymph nodes. Previous reports demonstrated that Cdc42 is inactivated upon DC-maturation to avoid continued Ag-acquisition. To further study the molecular mechanisms of DC-control by Cdc42, we used bone marrow-derived DCs from Cdc42-deficient mice. We show that Cdc42-deficient DCs are phenotypically mature without additional maturation stimuli, as they upregulate CD86 from intracellular storages to the cell surface. They also accumulate invariant chain (Ii)-MHC class II complexes at the cell surface, which cannot efficiently present peptide Ag for priming of Ag-specific CD4 T cells. Lack of Cdc42 in immature DCs does not allow MHC class II maturation, as lysosomal Cathepsins are lost into the supernatant and Ii-MHC class II complexes cannot mature. Therefore Cdc42-deficient DCs are "pseudomature" and lose most functional hallmarks of antigen-presenting cells. Our results propose that Cdc42 keeps DCs in an immature state, while downregulation of Cdc42-activity during maturation facilitates generation of CD86+MHCII+ mature DCs.
2015-10-12 | PXD001934 | Pride
Project description:Here we investigate the relevance of the microenvironment in follicular lymphoma by studying the effect of the lectin DC-SIGN, expressed by macrophages on B-cell receptor activation. We compare the effect of DC-SIGN and anti-IgM stimulation on FL by treating 3 FL samples with 20 μg/ml of goat F(ab’)2 anti-IgM, 20 μg/ml of DC-SIGN-Fc or left untreated for 4 hours at 37°C. Total RNA was extracted using an RNeasy mini kit (Qiagen) and polyA libraries were 75bp PE sequenced on a HiSeq4000 (Ilumina). After gene expression profiling analysis we found that, although DC-SIGN-Fc appears to elicit a weaker transcriptional response than anti-IgM, the responses are closely related and encompass a wide range of canonical BCR response pathways.
2020-01-31 | E-MTAB-8708 | biostudies-arrayexpress
Project description:Dendritic cells (DC) serve a key function in host defense, linking innate detection of microbes to the activation of pathogen-specific adaptive immune responses. Whether there is cell-intrinsic recognition of HIV-1 by host innate pattern-recognition receptors and subsequent coupling to antiviral T cell responses is not yet known. DC are largely resistant to infection with HIV-1, but facilitate infection of co-cultured T-helper cells through a process of trans-enhancement. We show here that, when DC resistance to infection is circumvented, HIV-1 induces DC maturation, an antiviral type I interferon response and activation of T cells. This innate response is dependent on the interaction of newly-synthesized HIV-1 capsid (CA) with cellular cyclophilin A (CypA) and the subsequent activation of the transcription factor IRF3. Because the peptidyl-prolyl isomerase CypA also interacts with CA to promote HIV-1 infectivity, our results suggest that CA conformation has evolved under opposing selective pressures for infectivity versus furtiveness. Thus, a cell intrinsic sensor for HIV-1 exists in DC and mediates an antiviral immune response, but it is not typically engaged due to absence of DC infection. The virulence of HIV-1 may be related to evasion of this response, whose manipulation may be necessary to generate an effective HIV-1 vaccine.
2010-09-09 | GSE22589 | GEO
Project description:Identification of MEK-ERK or p38MAPK dependent genes in human monocyte derived dendritic cells. Dendritic cells (DC) promote tolerance or immunity depending on their maturation state. Previous studies have revealed that DC maturation is enhanced or accelerated upon MEK-ERK signaling pathway inhibition. We have now determined the contribution of MEK-ERK activation to the profile of gene expression of human immature monocyte-derived dendritic cells (MDDC) and peripheral blood myeloid DC. ERK inhibition altered the expression of genes that mediate CCL19-directed migration (CCR7) and LDL binding (CD36, SCARB1, OLR1, CXCL16) by immature DC. Besides, ERK upregulated CCL2 expression while impaired the expression of DC maturation markers (RUNX3, ITGB7, IDO1). MEK-ERK-regulated genes exhibited an over-representation of cognate sequences for the Aryl Hydrocarbon Receptor (AhR) transcription factor, and we show that AhR mediates some of the ERK-dependent transcriptional effects in DC. Therefore, MEK-ERK signaling pathway regulates antigen capture, lymph node homing and the acquisition of maturation-associated genes, and its contribution to the maintenance of the immature state of MDDC and myeloid DC is partly dependent on the activity of AhR. Since pharmacological modulation of the MEK-ERK signaling pathway has been proposed as a potential therapeutic strategy for cancer, our findings indicate that ERK inhibitors might influence the generation of anti-tumor responses through regulation of critical DC effector functions. Human peripheral blood monocytes from three independent healthy donors (DC4, DC5 and DC7) were isolated by anti-CD14-labeled magnetic microbeads. CD14+ monocytes were cultured for 5 days in RPMI 10% FCS containing GM-CSF and IL-4 to generate immature monocyte-derived dendritic cells (MDDC). Immature MDDC were exposed to MEK inhibitor, U0126, or p38MAPK inhibitor, SB203580 for 1 hour and a final dose of GM-CSF and IL-4 were added to the culture. Cells were collected for analysis after 4, 10 or 24 hours.Total RNA from each condition was extracted using the All prep DNA/RNA/protein mini kit (Qiagen) and hybridized to an Agilent Human Whole Genome (4x44) Oligo Microarray. All experimental procedures were performed following manufacturer instructions.
2013-05-03 | E-GEOD-39745 | biostudies-arrayexpress
Project description:Identification of MEK-ERK or p38MAPK dependent genes in human monocyte derived dendritic cells. Dendritic cells (DC) promote tolerance or immunity depending on their maturation state. Previous studies have revealed that DC maturation is enhanced or accelerated upon MEK-ERK signaling pathway inhibition. We have now determined the contribution of MEK-ERK activation to the profile of gene expression of human immature monocyte-derived dendritic cells (MDDC) and peripheral blood myeloid DC. ERK inhibition altered the expression of genes that mediate CCL19-directed migration (CCR7) and LDL binding (CD36, SCARB1, OLR1, CXCL16) by immature DC. Besides, ERK upregulated CCL2 expression while impaired the expression of DC maturation markers (RUNX3, ITGB7, IDO1). MEK-ERK-regulated genes exhibited an over-representation of cognate sequences for the Aryl Hydrocarbon Receptor (AhR) transcription factor, and we show that AhR mediates some of the ERK-dependent transcriptional effects in DC. Therefore, MEK-ERK signaling pathway regulates antigen capture, lymph node homing and the acquisition of maturation-associated genes, and its contribution to the maintenance of the immature state of MDDC and myeloid DC is partly dependent on the activity of AhR. Since pharmacological modulation of the MEK-ERK signaling pathway has been proposed as a potential therapeutic strategy for cancer, our findings indicate that ERK inhibitors might influence the generation of anti-tumor responses through regulation of critical DC effector functions.
2013-05-03 | GSE39745 | GEO