Project description:microRNA-126 is a microRNA predominately expressed by endothelial cells and controls angiogenesis. Unexpectedly, we found that mice deficient in miR-126 have a major impairment in their innate response to pathogen-associated nucleic acids, as well as HIV, which results in more widespread cell infection. Further examination revealed that this was due to miR-126 control of plasmacytoid DC (pDC) homeostasis and function, and that miR-126 regulates expression of TLR7, TLR9, NFkB1 and other innate response genes, as well as VEGF-receptor 2 (VEGFR2). Deletion of VEGFR2 on DCs resulted in reduced interferon production, supporting a role for VEGFR2 in miR-126 regulation of pDCs. These studies identify the miR-126/VEGFR2 axis as an important regulator of the innate response that operates through multiscale control of pDCs.
Project description:microRNA-126 is a microRNA predominately expressed by endothelial cells and controls angiogenesis. Unexpectedly, we found that mice deficient in miR-126 have a major impairment in their innate response to pathogen-associated nucleic acids, as well as HIV, which results in more widespread cell infection. Further examination revealed that this was due to miR-126 control of plasmacytoid DC (pDC) homeostasis and function, and that miR-126 regulates expression of TLR7, TLR9, NFkB1 and other innate response genes, as well as VEGF-receptor 2 (VEGFR2). Deletion of VEGFR2 on DCs resulted in reduced interferon production, supporting a role for VEGFR2 in miR-126 regulation of pDCs. These studies identify the miR-126/VEGFR2 axis as an important regulator of the innate response that operates through multiscale control of pDCs. Plasmactyoid dendritic cells were FACS-sorted from spleens from wildtype and miR-126 KO mice and their RNA extracted. RNA was amplified, labeled and hybridized to Mouse Gene 1.0 ST arrays with the data generation and quality control pipeline of 19 the Immunological Genome Project (www.immgen.org). Raw data were background-corrected and normalized using the RMA algorithm.
Project description:The interactions between proteins and nucleic acids have a fundamental function in many biological processes well beyond nuclear gene transcription and include RNA homeostasis, protein translation and pathogen sensing for innate immunity. While our knowledge of the ensemble of proteins binding individual mRNAs in mammalian cells has greatly been augmented by recent surveys, no systematic study on the native proteins of human cells differentially engaging various types of nucleic acids in a non sequence-specific manner has been reported. We designed an experimental approach to cover the non sequence-specific RNA and DNA binding space broadly, including methylation, and test for its ability to interact with the human proteome. We used 25 rationally designed nucleic acid probes in an affinity purification mass spectrometry and bioinformatics workflow to identify proteins from whole cell extracts of three different human cell lines. The proteins were profiled for their binding preferences to the different general types of nucleic acids. The study identified 746 high confidence direct binders, 249 of which were devoid of previous experimental evidence for binding nucleic acids. We could assign 513 specific affinities for sub-types of nucleic acid probes to 219 distinct proteins and to individual domains. The evolutionary conserved protein YB-1, previously associated with cancer and gene regulation, is shown to bind methylated cytosine preferentially conferring YB-1 a potential epigenetic function. Collectively, the dataset represents a rich resource of experimentally determined nucleic acid-specific binding proteins in humans and, indirectly, for other species. Identification of genomic YB-1 binding sites in HEK293 cells
Project description:Hypoxia controls reparative angiogenesis. MiRNAs are master regulators of gene expression in hypoxia and angiogenesis. However, we do not yet have a clear understanding of how hypoxia-induced miRNAs modulate vasoreparative processes. Here, we identify miR-130a as a mediator of the hypoxic response in human primary endothelial colony forming cells (ECFCs), a well-characterized subtype of endothelial progenitor. Under hypoxic conditions, miR-130a overexpression enhances ECFC pro-angiogenic capacity in vitro and potentiates their vasoreparative properties in vivo. Mechanistically, miR-130a orchestrates upregulation of VEGFR2, activation of STAT3-dependent transcription, and accumulation of HIF1α via translational inhibition of DDX6. These findings unveil a new role for miR-130a in hypoxia, whereby it modulates the VEGFR2/STAT3/HIF1α axis to increase the vasoregenerative capacity of ECFCs.
Project description:Acute myeloid leukemia (AML) harboring inv(16)(p13q22) expresses high levels of miR-126. Here we show that the CBFB-MYH11 (CM) fusion gene upregulates miR-126 expression through aberrant miR-126 transcription and perturbed miR-126 biogenesis via the HDAC8/RAN-XPO5-RCC1 axis. Aberrant miR-126 upregulation promotes survival of leukemia-initiating progenitors and is critical for initiating and maintaining CM-driven AML. We show that miR-126 enhances MYC activity through the SPRED1/PLK2-ERK-MYC axis. Notably, genetic deletion of miR-126 significantly reduced AML rate and extended survival in CM knock-in mice. Therapeutic depletion of miR-126 with an anti-miR-126 (miRisten) inhibited AML cell survival, reduced leukemia burden and leukemia stem cell (LSC) activity in inv(16) AML murine and xenograft models. Combination of miRisten with chemotherapy further enhanced the anti-leukemia and anti-LSC activity. Overall, this study provides molecular insights for the mechanism and impact of miR-126 dysregulation in leukemogenesis and highlights the potential of miR-126 depletion as a new therapeutic approach for inv(16) AML.
Project description:The interactions between proteins and nucleic acids have a fundamental function in many biological processes well beyond nuclear gene transcription and include RNA homeostasis, protein translation and pathogen sensing for innate immunity. While our knowledge of the ensemble of proteins binding individual mRNAs in mammalian cells has greatly been augmented by recent surveys, no systematic study on the native proteins of human cells differentially engaging various types of nucleic acids in a non sequence-specific manner has been reported. We designed an experimental approach to cover the non sequence-specific RNA and DNA binding space broadly, including methylation, and test for its ability to interact with the human proteome. We used 25 rationally designed nucleic acid probes in an affinity purification mass spectrometry and bioinformatics workflow to identify proteins from whole cell extracts of three different human cell lines. The proteins were profiled for their binding preferences to the different general types of nucleic acids. The study identified 746 high confidence direct binders, 249 of which were devoid of previous experimental evidence for binding nucleic acids. We could assign 513 specific affinities for sub-types of nucleic acid probes to 219 distinct proteins and to individual domains. The evolutionary conserved protein YB-1, previously associated with cancer and gene regulation, is shown to bind methylated cytosine preferentially conferring YB-1 a potential epigenetic function. Collectively, the dataset represents a rich resource of experimentally determined nucleic acid-specific binding proteins in humans and, indirectly, for other species.
Project description:Cutaneous lupus erythematosus (CLE) is a photosensitive autoimmune disease characterized by a strong type-I-interferon (IFN) associated inflammation. Keratinocytes are known to determine the interface-dermatitis-pattern in CLE by production of proinflammatory cytokines in the lower epidermis. These cytokines drive a cytotoxic anti-epithelial immune response resulting in keratinocytic cell death and release of endogenous nucleic acids (eNA). We hypothesized that these eNA (RNA- and DNA-motifs) have the capacity to activate innate immune pathways in keratinocytes via pathogen-recognition-receptors (PRR). Gene expression analyses revealed an excessive activation of innate immune response pathways with strong expression of IFN-regulated cytokines in CLE skin lesions. Cultured keratinocytes produce large amounts of these cytokines in response to stimulation of PRR with eNA. UV-stimulation enhances the immunogenicity of eNA and induces CLE-like skin lesions in knockout mice lacking the cytosolic DNase TREX1. Our results provide evidence for a pathogenetic role of endogenous nucleic acids in CLE. They are released within the cytotoxic inflammation along the dermo-epidermal junction and have the capacity to drive the LE-typical inflammation. UV-irradiation supports this inflammation by generation of highly immunostimulatory DNA motifs (8-OHG). These findings explain the photosensitivity of lupus patients and identify pathways of the innate immune system as targets for future therapies.
Project description:Toll-like receptors (TLRs) are mediators in the innate immune response by recognizing nucleic acids derived from microbial components as for TLR9 binding ability for CpG rich bacterial DNA. We studied the differential expression by microarrays of all known T-UCRs and near genes in a series of 6 primary B-CLL cases cells comparing cells treated in vitro with CpG ODN versus mock controls.
Project description:The goal of this study is to investigate the cell type-specific targets of miR-126-3p in human lung microvascular endothelial cells (HLMVEC). Following the transfections of HLMVEC with non-targeting negative controls, miR-126 mimics, or miR-126 antisense inhibitors, we calculated the copy number concentration of miR-126 in each sample and performed genome-wide RNA sequencing. Plotting the gene expression data for each transfection condition (Scramble, 126-OE and 126-KD) against their respective miR-126 concentrations, we performed a linear regression analysis to discover genes that were the most sensitive to changes in miR-126 levels. We identified 1258 genes that were upregulated and 1436 genes that were downregulated by miR-126-3p. Further comparison between the downregulated genes in HLMVEC and targets predicted by online databases including TargetScan and miRDB revealed 6 genes as potential direct targets of miR-126-3p. Our study is the first to report targets of miR-126-3p in HLMVEC and demonstrate the effect of miR-126 level alteration on the HLMVEC global transcriptome. These results add to the diverse functions of miR-126-3p in different endothelial cell types and provide basis for the development of cell type-specific treatment for lung diseases.