19 research outputs found
Transcriptional and Linkage Analyses Identify Loci that Mediate the Differential Macrophage Response to Inflammatory Stimuli and Infection
Macrophages display flexible activation states that range between pro-inflammatory (classical activation) and anti-inflammatory (alternative activation). These macrophage polarization states contribute to a variety of organismal phenotypes such as tissue remodeling and susceptibility to infectious and inflammatory diseases. Several macrophage- or immune-related genes have been shown to modulate infectious and inflammatory disease pathogenesis. However, the potential role that differences in macrophage activation phenotypes play in modulating differences in susceptibility to infectious and inflammatory disease is just emerging. We integrated transcriptional profiling and linkage analyses to determine the genetic basis for the differential murine macrophage response to inflammatory stimuli and to infection with the obligate intracellular parasite Toxoplasma gondii. We show that specific transcriptional programs, defined by distinct genomic loci, modulate macrophage activation phenotypes. In addition, we show that the difference between AJ and C57BL/6J macrophages in controlling Toxoplasma growth after stimulation with interferon gamma and tumor necrosis factor alpha mapped to chromosome 3, proximal to the Guanylate binding protein (Gbp) locus that is known to modulate the murine macrophage response to Toxoplasma. Using an shRNA-knockdown strategy, we show that the transcript levels of an RNA helicase, Ddx1, regulates strain differences in the amount of nitric oxide produced by macrophage after stimulation with interferon gamma and tumor necrosis factor. Our results provide a template for discovering candidate genes that modulate macrophage-mediated complex traits
Recommended from our members
Transcriptional and Linkage Analyses Identify Loci that Mediate the Differential Macrophage Response to Inflammatory Stimuli and Infection.
Macrophages display flexible activation states that range between pro-inflammatory (classical activation) and anti-inflammatory (alternative activation). These macrophage polarization states contribute to a variety of organismal phenotypes such as tissue remodeling and susceptibility to infectious and inflammatory diseases. Several macrophage- or immune-related genes have been shown to modulate infectious and inflammatory disease pathogenesis. However, the potential role that differences in macrophage activation phenotypes play in modulating differences in susceptibility to infectious and inflammatory disease is just emerging. We integrated transcriptional profiling and linkage analyses to determine the genetic basis for the differential murine macrophage response to inflammatory stimuli and to infection with the obligate intracellular parasite Toxoplasma gondii. We show that specific transcriptional programs, defined by distinct genomic loci, modulate macrophage activation phenotypes. In addition, we show that the difference between AJ and C57BL/6J macrophages in controlling Toxoplasma growth after stimulation with interferon gamma and tumor necrosis factor alpha mapped to chromosome 3, proximal to the Guanylate binding protein (Gbp) locus that is known to modulate the murine macrophage response to Toxoplasma. Using an shRNA-knockdown strategy, we show that the transcript levels of an RNA helicase, Ddx1, regulates strain differences in the amount of nitric oxide produced by macrophage after stimulation with interferon gamma and tumor necrosis factor. Our results provide a template for discovering candidate genes that modulate macrophage-mediated complex traits
Autoantibodies against podocytic UCHL1 are associated with idiopathic nephrotic syndrome relapses and induce proteinuria in mice
International audienc
Basophils and IgE contribute to mixed connective tissue disease development
International audienceBackground: Mixed connective tissue disease (MCTD) is a rare and complex autoimmune disease that presents mixed features with other connective tissue diseases, such as systemic lupus erythematosus, systemic sclerosis, and myositis. It is characterized by high levels of anti-U1 small nuclear ribonucleoprotein 70k autoantibodies and a high incidence of life-threatening pulmonary involvement. The pathophysiology of MCTD is not well understood, and no specific treatment is yet available for the patients. Basophils and IgE play a role in the development of systemic lupus erythematosus and thus represent new therapeutic targets for systemic lupus erythematosus and other diseases involving basophils and IgE in their pathogenesis.Objective: We sought to investigate the role of basophils and IgE in the pathophysiology of MCTD.Methods: Basophil activation status and the presence of autoreactive IgE were assessed in peripheral blood of a cohort of patients with MCTD and in an MCTD-like mouse model. Basophil depletion and IgE-deficient animals were used to investigate the contribution of basophils and IgE in the lung pathology development of this mouse model.Results: Patients with MCTD have a peripheral basopenia and activated blood basophils overexpressing C-C chemokine receptor 3. Autoreactive IgE raised against the main MCTD autoantigen U1 small nuclear ribonucleoprotein 70k were found in nearly 80% of the patients from the cohort. Basophil activation and IgE anti-U1 small nuclear ribonucleoprotein 70k were also observed in the MCTD-like mouse model along with basophil accumulation in lymph nodes and lungs. Basophil depletion dampened lung pathology, and IgE deficiency prevented its development.Conclusions: Basophils and IgE contribute to MCTD pathophysiology and represent new candidate therapeutic targets for patients with MCTD
QTL inheritance and allele effects on different traits in AXB/BXA BMDM.
<p>AA = Homozygous AJ allele; BB = Homozygous B6 allele. BMDMs were grouped based on their genotypes at the marker on the QTL peak. <i>P</i>-values were corrected for multiple testing (26 individuals) using the Bonferroni test.</p><p>QTL inheritance and allele effects on different traits in AXB/BXA BMDM.</p
shRNA- mediated <i>Ddx1</i> knockdown in C57BL/B6J immortalized macrophages relieves NO inhibition.
<p>Fold knockdown of <i>Ddx1</i> and fold change in NO levels are relative to the <i>Ddx</i>1 expression and the amount of NO in cells transduced with control shRNA (<i>LacZ</i>), respectively. Knocking down <i>E2f6</i>, the other candidate gene at this locus, did not affect the amount of NO produced. Shown are values of NO (μM) fold change obtained from two independent experiments using three different shRNA constructs. The knockdown level is indicated by the black triangles. Fold knockdown was calculated using the 2<sup>deltadelta</sup><i>Ct</i> method. The shRNA transductions and NO measurements were done in 3 independent replicates.</p
The transcriptional response in BMDM is regulated by stimulation-specific <i>trans</i>-loci.
<p>Expression quantitative trait loci (eQTL) in the RI mice were mapped in A) non-stimulated, B) IFNG+TNF-stimulated, C) <i>Toxoplasma</i>-infected, and D) CpG-Stimulated BMDM. Each dot represents a single eQTL (transcript). Significant eQTL located ≤ 10 Mb from the start of the physical location of the corresponding gene were designated as <i>cis</i> mapping (diagonal lines). All other eQTL were designated as <i>trans</i>-mapping (vertical lines). eQTL significance was calculated after 1000 permutations and reported at genome-wide thresholds corresponding to FDR ≤ 10%. Red spots identify genes mapping to a <i>trans</i>-eQTL hotpot (<i>trans</i>-band).</p
BMDM from AJ and B6 mice differ in their response to various stimuli.
<p>A) Stimulation of macrophages for ~ 18 hrs with IFNG+TNF resulted in high production of NO by AJ macrophages (black bars), while B) stimulation with LPS led to higher production of IL-12 in C57BL/6J (B6) macrophages (white bars). C) Stimulation of murine macrophages with LPS or CPG resulted in significantly higher production of IL-10 in B6 macrophages compared to the AJ macrophages. D) B6 macrophages stimulated with IL-4 produced significantly more urea, compared to AJ macrophages, while LPS stimulation induced low amounts of urea in both AJ and B6 BMDM. E) AJ macrophages stimulated with CPG or LPS produced significantly higher amounts of the chemokine CCL22 compared to B6 macrophages. F) The IFNG+TNF stimulated macrophages have increased toxoplasmacidal activity, which is slightly reduced in the presence of aminoguanidine (AG), an inducible nitric oxide synthase inhibitor. Where there was no detectable amount of cytokine/chemokine measured, including in all control (non-stimulated) BMDM, we do not include cytokine/chemokine data in the figures. Three independent replicates; Mean (SD) * <i>p < 0</i>.<i>05</i> (Student’s t-test).</p
Functional enrichments in the large <i>trans</i>-eQTL hotspots in AXB/BXA macrophages following IFNG+TNF-stimulation, CpG-stimulation, or <i>Toxoplasma</i>-infection.
<p>Functional enrichments in the large <i>trans</i>-eQTL hotspots in AXB/BXA macrophages following IFNG+TNF-stimulation, CpG-stimulation, or <i>Toxoplasma</i>-infection.</p