RNAi profiling of mouse macrophage response to DAP12 knockdown in basal conditions and in the response to IL-4 Basal and IL-4 response in DAP12 (TYROBP) KO mice
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ABSTRACT: DAP12 is a transmembrane protein, expressed as a disulfide-bonded homodimer and bears an immunoreceptor tyrosine-based activation motif (ITAM). DAP12 is broadly expressed in hematopoietic cells and associates with a variety of cell surface receptors in lymphoid and myeloid cells. Macrophages express several DAP12-associated receptors including triggering receptors expressed by myeloid cells (TREM)-1,2 and 3, myeloid DAP12-associating lectin (MDL)-1, CD200R like proteins CD200R3/R4 and CD300C/D/E . Experiment Overall Design: The current experiment was designed to evaluate the effect of DAP12 knockdown on macrophage gene expression, both in basal conditions and in the response to IL-4.
Project description:DAP12 is a transmembrane protein, expressed as a disulfide-bonded homodimer and bears an immunoreceptor tyrosine-based activation motif (ITAM). DAP12 is broadly expressed in hematopoietic cells and associates with a variety of cell surface receptors in lymphoid and myeloid cells. Macrophages express several DAP12-associated receptors including triggering receptors expressed by myeloid cells (TREM)-1,2 and 3, myeloid DAP12-associating lectin (MDL)-1, CD200R like proteins CD200R3/R4 and CD300C/D/E . Keywords: Cell type comparison
Project description:Polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL) is an inherited brain and bone disease. It manifests as dementia and bone fractures. The PLOSL phenotype is caused by loss-of-function mutations in one of the two genes encoding the components of the DAP12/TREM2 receptor complex. The DAP12/TREM2 complex is expressed in cells of the myeloid lineage, including microglia in the central nervous system (CNS). The molecular mechanisms producing the CNS phenotype of PLOSL remain largely unknown. To gain insight into dysfunctional CNS pathways behind PLOSL, we performed genome-wide expression analysis of Dap12 (Tyrobp)-deficient mouse microglial cells. Keywords: knock-out response
Project description:Polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL) is an inherited brain and bone disease. It manifests as dementia and bone fractures. The PLOSL phenotype is caused by loss-of-function mutations in one of the two genes encoding the components of the DAP12/TREM2 receptor complex. The DAP12/TREM2 complex is expressed in cells of the myeloid lineage, including microglia in the central nervous system (CNS). The molecular mechanisms producing the CNS phenotype of PLOSL remain largely unknown. To gain insight into dysfunctional CNS pathways behind PLOSL, we performed genome-wide expression analysis of Dap12 (Tyrobp)-deficient mouse microglial cells. Keywords: knock-out response Transcript profiles of three wild type and three Dap12-deficient primary microglial cultures were analyzed.
Project description:Polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL) is an inherited brain and bone disease. It manifests as dementia and bone fractures. The PLOSL phenotype is caused by loss-of-function mutations in one of the two genes encoding the components of the DAP12/TREM2 receptor complex. The DAP12/TREM2 complex is expressed in cells of the myeloid lineage, including microglia in the central nervous system (CNS). The molecular mechanisms producing the CNS phenotype of PLOSL remain largely unknown. To gain insight into dysfunctional CNS pathways behind PLOSL, we performed genome-wide expression analysis of Dap12 (Tyrobp)-deficient mouse brain. In Dap12-deficient mice, we observed alterations in several pathways involved in synaptic function. In agreement with the myelin loss in PLOSL patients, we also saw changes in transcript levels of genes encoding myelin components. Keywords: knockout response
Project description:Polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL) is an inherited brain and bone disease. It manifests as dementia and bone fractures. The PLOSL phenotype is caused by loss-of-function mutations in one of the two genes encoding the components of the DAP12/TREM2 receptor complex. The DAP12/TREM2 complex is expressed in cells of the myeloid lineage, including microglia in the central nervous system (CNS). The molecular mechanisms producing the CNS phenotype of PLOSL remain largely unknown. To gain insight into dysfunctional CNS pathways behind PLOSL, we performed genome-wide expression analysis of Dap12 (Tyrobp)-deficient mouse brain. In Dap12-deficient mice, we observed alterations in several pathways involved in synaptic function. In agreement with the myelin loss in PLOSL patients, we also saw changes in transcript levels of genes encoding myelin components. Keywords: knockout response Transcript profiles of the midbrain (diencephalon and basal ganglia) of three Dap12-knockout and three heterozygous mice were analyzed.
Project description:NKG2D ligands are broadly expressed in cancer. To exploit this, we engineered an adaptor chimeric antigen receptor (CAR) termed NKG2D / Dap10-12 in which NKG2D is co-expressed with a fusion of Dap10 and the Dap12 endodomain. Dap10 was deployed to provide co-stimulation while Dap12 delivers an activation signal via a single immunoreceptor tyrosine-based activation motif (ITAM). NKG2D / Dap10-12 T-cells elicited compelling anti-tumor activity in several solid tumor xenograft models. Disease eradication was accompanied by sustained functional persistence, indicated by reproducible protection from secondary tumor re-challenge. Anti-cancer activity was consistently superior to an analog of a clinical stage linear CAR comprising an NKG2D-CD3 fusion. Mechanistically, functionality of NKG2D / Dap10-12 CAR T-cells was underpinned by transcriptomic re-programming to increase oxidative phosphorylation and ribosome biosynthesis..
Project description:Nasu-Hakola disease (NHD), also designated polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL), is a rare autosomal recessive disorder characterized by progressive presenile dementia and formation of multifocal bone cysts, caused by a loss-of-function mutation of DAP12 or TREM2. TREM2 and DAP12 constitute a receptor/adaptor complex expressed on osteoclasts, dendritic cells, macrophages, monocytes, and microglia. At present, the precise molecular mechanisms underlying development of leukoencephalopathy and bone cysts in NHD remain largely unknown. We established THP-1 human monocyte clones that stably express small interfering RNA (siRNA) targeting DAP12 for serving as a cellular model of NHD. Genome-wide transcriptome analysis identified a set of 22 genes consistently downregulated in DAP12 knockdown cells. They constituted the molecular network closely related to the network defined by cell-to-cell signaling and interaction, hematological system development and function, and inflammatory response, where NF-kappaB acts as a central regulator. These results suggest that a molecular defect of DAP12 in human monocytes deregulates the gene network pivotal for maintenance of myeloid cell function in NHD.
Project description:Nasu-Hakola disease (NHD), also designated polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL), is a rare autosomal recessive disorder characterized by progressive presenile dementia and formation of multifocal bone cysts, caused by a loss-of-function mutation of DAP12 or TREM2. TREM2 and DAP12 constitute a receptor/adaptor complex expressed on osteoclasts, dendritic cells, macrophages, monocytes, and microglia. At present, the precise molecular mechanisms underlying development of leukoencephalopathy and bone cysts in NHD remain largely unknown. We established THP-1 human monocyte clones that stably express small interfering RNA (siRNA) targeting DAP12 for serving as a cellular model of NHD. Genome-wide transcriptome analysis identified a set of 22 genes consistently downregulated in DAP12 knockdown cells. They constituted the molecular network closely related to the network defined by cell-to-cell signaling and interaction, hematological system development and function, and inflammatory response, where NF-kappaB acts as a central regulator. These results suggest that a molecular defect of DAP12 in human monocytes deregulates the gene network pivotal for maintenance of myeloid cell function in NHD. We found that both DAP12 knockdown and control clones were capable of equally responding to phorbol 12-myristate 13-acetate (PMA), a known inducer of morphological differentiation of THP-1 cells, by exhibiting almost similar gene expression profiles between both, following a 24-hour exposure to 50 nM PMA.
Project description:The TREM2-DAP12 receptor complex sustains microglia functions. Heterozygous TREM2 variants subtly impair microglia, facilitating manifestation of Alzheimer’s Disease in the elderly. Homozygous inactivating mutations of TREM2 or DAP12 cause Nasu-Hakola disease (NHD), an early-onset dementia with leukoencephalopathy, myelin loss and gliosis. Here we investigated the impact of DAP12 deficiency in microglia and collateral damage to other brain cells by single-nucleus RNA-seq in NHD patients and DAP12 loss-of-function (KΔ75) mice. KΔ75 mice showed signatures of impaired microglia activation that reverberated in mild dysfunction of other brain cells. Paradoxically, NHD microglia were activated and associated with astrocytosis, hypoxia, and neuronal loss signatures. We envision that KΔ75 signatures recapitulate an early NHD stage in which DAP12-deficient microglia fail to clear toxic products generated during brain development and homeostasis. Conversely, NHD signatures reflect a late disease stage in which accumulated toxic products cause a widespread tissue damage that elicits TREM2-DAP12-independent microgliosis, astrogliosis, hypoxia, and neuronal death. This TREM2-DAP12-independent microglia activation in NHD has bearing on potential microglia-based therapies.
Project description:TREM-1 is an orphan immunoreceptor expressed on monocytes, macrophages, and neutrophils. TREM-1 associates with and signals via the adapter protein DAP12/TYROBP, which contains an immunoreceptor tyrosine-based activation motif (ITAM). TREM-1 activation by receptor cross-linking is pro-inflammatory, and can amplify cellular responses to Toll-like receptor (TLR) ligands such as bacterial lipopolysaccharide (LPS). To investigate the cellular consequences of TREM-1 activation, we have characterized global gene expression changes in human monocytes in response to TREM-1 cross-linking in comparison to and combined with LPS. Both TREM-1 activation and LPS up-regulate chemokines, cytokines, matrix metalloproteases, and PTGS/COX2, consistent with a core inflammatory response. However, other immunomodulatory factors are selectively induced, including SPP1 and CSF1 (i.e., M-CSF) by TREM-1 activation and IL-23 and CSF3 (i.e., G-CSF) by LPS. Additionally, cross-talk between TREM-1 activation and LPS occurs on multiple levels. While synergy in GM-CSF protein production is reflected in commensurate mRNA abundance, comparable synergy in IL-1b protein production is not. TREM-1 activation also attenuates the induction of some LPS target genes, including those that encode IL-12 cytokine family subunits. Whereas positive TREM-1 outputs are abolished by the PI3K inhibitor wortmannin, this attenuation is largely PI3K-independent. These experiments provide a detailed analysis of the cellular consequences of TREM-1 activation, and highlight some of the complexity in signal integration between ITAM- and TLR-mediated signaling. Experiment Overall Design: 11 anonymous donors were treated with Vehicle, isotype control antibody, TREM1 antibody, LPS, isotype control antibody plus LPS and TREM1 antibody plus LPS