Triggering of B cell receptors (BCR) induces a massive synthesis of NFATc1 in splenic B cells. By inactivating the Nfatc1 gene and re-expressing NFATc1 we show that NFATc1 levels are critical for the survival of splenic B cells upon BCR stimulation. NFATc1 ablation led to decreased BCR-induced Ca++ flux and proliferation of splenic B cells, increased apoptosis and suppressed germinal centre formation and immunoglobulin class switch by T cell-independent antigens. By controlling IL-10 synthesis in B cells, NFATc1 supported the proliferation and IL-2 synthesis of T cells in vitro and appeared to contribute to the mild clinical course of Experimental Autoimmune Encephalomyelitis in mice bearing NFATc1-/- B cells. These data indicate NFATc1 as a key factor controlling B cell function.
NFATc1 affects mouse splenic B cell function by controlling the calcineurin--NFAT signaling network.
Specimen part
View SamplesIn this study we analyzed the myeloma cell contact-mediated changes on the transcriptome of skeletal precursor cells. Therefore, human mesenchymal stem cells (MSC) and osteogenic precursor cells (OPC) were co-cultured with the representative myeloma cell line INA-6 for 24 h. Afterwards, MSC and OPC were separated from INA-6 cells by fluorescence activated cell sorting. Total RNA of MSC and OPC fractions was used for whole genome array analysis.
Contact of myeloma cells induces a characteristic transcriptome signature in skeletal precursor cells -Implications for myeloma bone disease.
Sex, Age, Specimen part, Disease stage
View SamplesRationale: Estrogens attenuate cardiac hypertrophy and increase cardiac contractility via their cognate receptors ER and ER. Since female sex hormones enhance global glucose utilization and because myocardial function and mass are tightly linked to cardiac glucose metabolism we tested the hypothesis that expression and activation of the estrogen receptor (ER) might be required and sufficient to maintain physiological cardiac glucose uptake in the murine heart. Methods and Results: Cardiac glucose uptake quantified in vivo by 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) was strongly impaired in ovarectomized compared to gonadal intact female C57BL/6JO mice. The selective ER agonist 16-LE2 and the non-selective ER and ER agonist 17-estradiol completely restored cardiac glucose uptake in ovarectomized mice. Cardiac FDG uptake was strongly decreased in female ER knockout mice (ERKO) compared to wild type littermates. Biochemical assays, affymetrix cDNA array analysis, western blotting and immuno-staining of cardiac glucose transporters revealed a positive correlation of ER dependent cardiac FDG uptake with preserved cardiac glucose transporter-1 expression and micro-vascular localization. Conclusions: Systemic activation of the ER estrogen receptor is sufficient and its expression is required to maintain physiological glucose uptake in the murine heart, which is likely to contribute to known cardio-protective estrogen effects.
No associated publication
Sex, Age, Specimen part
View SamplesNeuronal function critically depends on coordinated subcellular distribution of mRNAs. Disturbed mRNA processing and axonal transport has been found in spinal muscular atrophy and could be causative for dysfunction and degeneration of motoneurons. Despite the advances made in characterizing the transport mechanisms of several axonal mRNAs, an unbiased approach to identify the axonal repertoire of mRNAs in healthy and degenerating motoneurons has been lacking. Here we used compartmentalized microfluidic chambers to investigate the somatodendritic and axonal mRNA content of cultured motoneurons by microarray analysis. In axons, transcripts related to protein synthesis and energy production were enriched relative to the somatodendritic compartment. Knockdown of Smn, the protein deficient in spinal muscular atrophy, produced a large number of transcript alterations in both compartments. Transcripts related to immune functions, including MHC class I genes, and with roles in RNA splicing were upregulated in the somatodendritic compartment. On the axonal side, transcripts associated with axon growth and synaptic activity were downregulated. These alterations provide evidence that subcellular localization of transcripts with axonal functions as well as regulation of specific transcripts with nonautonomous functions is disturbed in Smn-deficient motoneurons, most likely contributing to the pathophysiology of spinal muscular atrophy.
Subcellular transcriptome alterations in a cell culture model of spinal muscular atrophy point to widespread defects in axonal growth and presynaptic differentiation.
Specimen part
View SamplesIn the marrow and lymphatic tissues, chronic lymphocytic leukemia (CLL) cells interact with accessory cells that constitute the leukemia microenvironment. In lymphatic tissues, CLL cells are interspersed with CD68+ nurselike cells (NLC) and T cells. However, the mechanism regulating co-localization of CLL cells and these accessory cells are largely unknown. To dissect the molecular cross-talk between CLL and NLC, we profiled the gene expression of CD19-purified CLL cells before and after co-culture with NLC. NLC co-culture induced high-level expression of B cell maturation antigen (BCMA) and two chemoattractants (CCL3, CCL4) by CLL cells. Supernatants from CLL-NLC co-cultures revealed high CCL3/CCL4 protein levels. B cell receptor triggering also induced a robust induction of CCL3 and CCL4 expression by CLL cells, which was almost completely abrogated by a specific Syc inhibitor, R406. High CCL3 and CCL4 plasma levels in CLL patients suggest that activation of this pathway plays a role in vivo. These studies reveal a novel mechanism of cross-talk between CLL cells and their microenvironment, namely the secretion of two T cell chemokines by CLL-NLC interaction and in response to BCR stimulation. Through these chemokines, CLL cells can recruit accessory cells, and thereby actively create a microenvironment that favors their growth and survival.
High-level expression of the T-cell chemokines CCL3 and CCL4 by chronic lymphocytic leukemia B cells in nurselike cell cocultures and after BCR stimulation.
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View SamplesNatalizumab is a recombinant monoclonal antibody raised against integrin alpha-4 (CD49d). It is approved for the treatment of patients with multiple sclerosis (MS), a chronic inflammatory autoimmune disease of the CNS. Natalizumab blocks leukocyte extravasation across the blood-brain barrier by inhibiting the molecular interaction between integrin alpha-4/beta-1 heterodimers expressed on leukocytes and VCAM-1 on inflammatory-activated CNS endothelium. Here we investigated whether binding of this adhesion-blocking antibody to T lymphocytes modulated their phenotype by direct induction of intracellular signaling events. Natalizumab induced a mild upregulation of IL-2, IFN-gamma and IL-17 expression in activated primary human CD4+ T cells propagated ex vivo from healthy donors, consistent with a pro-inflammatory costimulatory effect on lymphokine expression. Overall, the relative effect of natalizumab was more pronounced in less than in fully activated T cells. Along with this, natalizumab binding triggered rapid MAPK/ERK phosphorylation. Furthermore, it decreased CD49d surface expression on effector cells within a few hours. Sustained CD49d downregulation could be attributed to integrin internalization and degradation. Importantly, also CD4+ T cells from some MS patients receiving their very first dose of natalizumab produced more IL-2, IFN-gamma and IL-17 already 24 h after infusion. Together these data indicate that in addition to its adhesion-blocking mode of action, natalizumab possesses mild direct signaling capacities, which may support a pro-inflammatory phenotype of peripheral blood T lymphocytes. This might explain why a rebound of disease activity is observed in some MS patients after natalizumab cessation.
Natalizumab exerts direct signaling capacity and supports a pro-inflammatory phenotype in some patients with multiple sclerosis.
Specimen part, Disease, Disease stage, Treatment
View Samplesprenatal stress response, genetic modification
No associated publication
Sex, Specimen part, Treatment
View SamplesGenome-wide comparative gene expression analysis of callus tissue of osteoporotic mice (Col1a1-Krm2 and Lrp5-/-) and wild-type were performed to identify candidate genes that might be responsible for the impaired fracture healing observed in Col1a1-Krm2 and Lrp5-/- mice.
Osteoblast-specific Krm2 overexpression and Lrp5 deficiency have different effects on fracture healing in mice.
Sex, Age, Specimen part
View SamplesUsing measles virus induced T cell suppression as a model, we established that T cell inhibitory protein isoforms can be produced from alternatively spliced pre-mRNAs as a result of virus-mediated ablation of T cell receptor dependent activation of the phosphatidylinositol-3-kinase (PI3K). To asses production of alternative splice variants in response to PI3K abrogation in T cells at a whole cell level, we performed a Human Exon 1.0 ST Array on RNAs isolated from T cells stimulated only or stimulated after PI3K inhibition. We developed a simple algorithm based on a splicing index to detect genes that undergo alternative splicing (AS) or are differentially regulated (RG) on T cell suppression. Applying our algorithm on this model 9% of the genes were assigned as AS, while only 3% were attributed to RG. Though there are overlaps, AS and RG genes differed with regard to functional regulated at the level of AS or RG were found enriched in different functional groups with AS targeting e. g. extra cellular matrix (ECM)-receptor interaction and focal adhesion, while cytokine-receptor interaction, Jak-STAT and p53 pathways were mainly RG. When combined, AS/RG dependent alterations targeted pathways essential for T cell receptor signaling, cytoskeletal dynamics and cell cycle entry strongly supporting the notion that PI3K abrogations interferes with key T cell activation processes at both levels, and that candidates represented within both categories bear the potential to actively contribute to T cell suppression
Accumulation of splice variants and transcripts in response to PI3K inhibition in T cells.
Specimen part, Treatment, Subject
View SamplesTherapy of autoimmune diseases by tolerogenic dendritic cells (DCs) represents an interesting option for clinical application. Mostly, immature or semi-mature stages of DCs have been shown to convert nave T cells into FoxP3+ induced regulatory T cells (iTreg). Here we found that murine bone marrow-derived DCs (BM-DCs) matured with cholera toxin (CT) produced cytotoxic T lymphocyte antigen 2 (CTLA-2) via cAMP signaling. CTLA-2 is a cathepsin L inhibitor, however, it exerted cathepsin L-independent tolerogenic functions as shown with cathepsin L knock-out BM-DCs. High or low dose CT (CThi, CTlo) or cAMP treatment of BM-DCs, but not other stimuli such as LPS or TNF, induced mRNA of both isoforms of CTLA-2 and CTLA-2. CThi-, CTlo- or cAMP-DCs display a mature phenotype (MHC IIhi, costimulationhi). Importantly, only CThi DCs secreted IL-1, IL-6 and IL-23. Consequently, CThi DCs instructed Th17 cell polarization while, CTlo- or cAMP-DCs induced TGF--dependent FoxP3+ iTreg conversion but little or no Th17 cells. iTreg conversion could be reduced by blocking of CTLA-2 with siRNAs and in accordance, addition of recombinant CTLA-2 increased the conversion towards iTreg in vitro. Injection of CTlo- or cAMP-DCs exerted MOG peptide-specific protective effects in experimental autoimmune encephalomyelitis (EAE). Together, we identified CTlo- or cAMP-induced CTLA-2 production by BM-DCs as a tool to enhance their iTreg induction in vitro and in vivo. These findings point to CTLA-2 as a novel mediator of immune evasion by cholera bacteria and its potential use to treat autoimmune diseases.
No associated publication
Specimen part
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