Microglia are resident CNS immune cells that are active sensors in healthy brain and versatile effectors under pathological conditions. Cerebral ischemia induces a robust neuroinflammatory response that includes marked changes in the gene expression and phenotypic profile of a variety of endogenous CNS cell types (astrocytes, neurons, microglia) as well as an influx of leukocytic cells (neutrophils, macrophages, T-cells) from the periphery. Many molecules and conditions can trigger a transformation of resting (or surveying) microglia to an activated (alerted/reactive) state. Here we review recent developments in the literature that relate to microglial activation in the experimental setting of in vitro and in vivo ischemia. We also present new data from our own laboratory demonstrating the direct effects of in vitro ischemic conditions on the microglial phenotype and genomic profile. Emphasis is placed on the role of specific molecular signaling systems such as hypoxia inducible factor-1 (HIF-1) and toll-like receptor-4 (TLR4) in regulating the microglial response in this setting. We then review histological and recent novel radiological data that confirms a key role for microglial activation in the setting of ischemic stroke in humans. We discuss recent progress in the pharmacological and molecular targeting of microglia in acute ischemic stroke. Finally, we explore how recent studies on ischemic preconditioning have increased interest in preemptively targeting microglial activation in order to reduce stroke severity.
Microglia in ischemic brain injury.
Specimen part
View SamplesWe report the genome-wide RNA sequencing of bone marrow derived macrophages after sequential TLR agonist stimulation. Overall design: Examination of sequential TLR agonist stimulation. Bone marrow derived macrophages (BMDMs) were prepared from male animals 6-12 weeks of age. Cells were isolated from femurs and tibias. The bone marrow cells were and grown in macrophage growth medium (RPMI 1640 supplemented with 10% FBS (Gibco), 1% penicillin-streptomycin (Gibco), 2 mM L-glutamine (Gibco), 1 mM sodium pyruvate (Gibco), 0.01 M HEPES (AmericanBio), and 30% L929-conditioned media as a source of CSF-1), and plated on petri dishes. Macrophage growth medium was supplemented on day 3. Cells were plated for use on day 6. For sequential stimuli, cells were first stimulated with, PBS, 100 ng/mL Poly I:C (InvivoGen), or 5 ng/mL LPS derived from Escherichia coli 055:B5 (Sigma-Aldrich). 24 hours after the initial stimulation, the media was removed and cells were washed twice with warmed macrophage growth media, and then the media was replaced with Poly I:C or LPS.
Specific sequences of infectious challenge lead to secondary hemophagocytic lymphohistiocytosis-like disease in mice.
Specimen part, Cell line, Subject
View SamplesPrevious studies indicate that the triterpene glycoside actein from the herb black cohosh inhibits growth of human breast cancer cells. This study seeks to identify genes altered in human breast cancer cells by treatment with actein, using gene expression analysis. We treated MDA-MB-453 human breast cancer cells with actein at 2 doses, 20 or 40 g/mL, for 6 or 24 h. We identified 5 genes that were activated after each of the treatments that are known to play a role in cellular responses to diverse stresses, including the DNA damage and unfolded protein responses. In addition, four genes that mediate the integrated stress response (ISR), including activating transcription factor 4, were induced under at least one of the 4 treatment conditions. We used hierarchical clustering to define clusters comprising patterns of gene expression. Two ISR genes, activating transcription factor 3 (ATF3) and DNA damage- inducible transcript 3, and lipid biosynthetic genes were activated after exposure to actein at 40 g/mL for 6 h, whereas the cell cycle genes cyclin E2 and cell division cycle 25A were repressed. Our results suggest that actein induces 2 phases of the ISR, the survival phase and the apoptotic phase, depending on the dose and duration of treatment. We confirmed the results of gene expression analysis with real-time RT-PCR for 18 selected genes and Western blot analysis for ATF3. Since actein activated transcription factors that enhance apoptosis, and repressed cell cycle genes, it may be useful in the prevention and therapy of breast cancer.
The growth inhibitory effect of actein on human breast cancer cells is associated with activation of stress response pathways.
No sample metadata fields
View SamplesPurpose: To compare the transcriptomes of IL-21-expressing, IL-21 and IL-4-expressing, and IL-4 expressing follicular helper T (Tfh) cells and Th2 cells in the spleen at 8 days following helminth infection Methods: Cell sorting of the populations was done for CD4+B220-CD44hiCXCR5hiPD-1hi cells of the various types, followed by mRNA purification. Overall design: CD4+Splenic T cell mRNA profiles 8 days post-infection of IL-21/IL-4 dual reporter mice with Nippostrongylus brasiliensis were generated by mRNA sequencing using Illumina HiSeq 2000.
TFH cells progressively differentiate to regulate the germinal center response.
Specimen part, Subject
View SamplesIn addition to being causally linked to the formation of multiple tumor types, tobacco use has been associated with decreased anticancer treatment efficacy and reduced survival time. A detailed understanding of the cellular mechanisms that are affected by tobacco smoke should facilitate the development of improved preventive and therapeutic strategies. We have investigated the effects of a tobacco smoke (TS) extract on the transcriptome of MSK-Leuk1 cells, a cellular model of oral leukoplakia. Using Affymetrix HGU133 Plus 2 arrays, 411 differentially expressed probesets were identified. The observed transcriptome changes were grouped according to functional information, and translated into molecular interaction network maps and signaling pathways. Pathways related to cellular proliferation, inflammation, apoptosis and tissue injury appeared to be perturbed. Analysis of networks connecting the affected genes identified specific molecular interactions, hubs and key transcription regulators affected by TS. Thus TS was found to induce several EGFR ligands forming an EGFR-centered molecular interaction network, as well as several AhR-dependent genes, including the xenobiotic metabolizing enzymes CYP1A1 and CYP1B1. Notably, the latter findings in vitro are consistent with our parallel finding that levels of CYP1A1 and CYP1B1 were increased in oral mucosa of smokers. Collectively, these results offer insights into the mechanisms underlying the procarcinogenic effects of TS and raise the possibility that inhibitors of EGFR or AhR signaling will prevent or delay the development of tobacco smoke-related tumors. Moreover, the inductive effects of TS on xenobiotic metabolizing enzymes may help explain reduced efficacy of chemotherapy, and suggest targets for chemopreventive agents in smokers.
Effects of tobacco smoke on gene expression and cellular pathways in a cellular model of oral leukoplakia.
No sample metadata fields
View SamplesNCI-60 cancer cell lines were profiled with their genome-wide gene expression patterns using Affymetrix HG-U133A chips.
A strategy for predicting the chemosensitivity of human cancers and its application to drug discovery.
No sample metadata fields
View Samples40 bladder cancer cell lines were profiled with their genome-wide gene expression patterns using Affymetrix HG-U133A chips.
A strategy for predicting the chemosensitivity of human cancers and its application to drug discovery.
No sample metadata fields
View SamplesT follicular helper (Tfh) cells are a subset of CD4+ T helper (Th) cells that migrate into germinal centers and promote B cell maturation into memory B and plasma cells. Tfh cells are necessary for promotion of protective humoral immunity following pathogen challenge, but when aberrantly regulated, drive pathogenic antibody formation in autoimmunity and undergo neoplastic transformation in angioimmunoblastic T-cell lymphoma and other primary cutaneous T-cell lymphomas. Limited information is available on the expression and regulation of genes in human Tfh cells. Using a fluorescence activated cell sorting-based strategy, we obtained primary Tfh and non-Tfh T effector (Teff) cells from tonsils and prepared genome-wide maps of active, intermediate, and poised enhancers determined by ChIP-seq, with parallel transcriptome analyses determined by RNA-seq. Tfh cell enhancers were enriched near genes highly expressed in lymphoid cells or involved in lymphoid cell function, with many mapping to sites previously associated with autoimmune disease in genome-wide association studies. A group of active enhancers unique to Tfh cells associated with differentially expressed genes was identified. Fragments from these regions directed expression in reporter gene assays. These data provide a significant resource for studies of T lymphocyte development and differentiation and normal and perturbed Tfh cell function. Overall design: Using a fluorescence activated cell sorting-based strategy, we obtained primary Tfh and non-Tfh T effector (Teff) cells from tonsils and prepared genome-wide maps of active, intermediate, and poised enhancers determined by ChIP-seq, with parallel transcriptome analyses determined by RNA-seq.
Global transcriptome analysis and enhancer landscape of human primary T follicular helper and T effector lymphocytes.
No sample metadata fields
View SamplesTumor epithelium and surrounding stromal cells were isolated using laser capture microdissection of human breast cancer to examine differences in gene expression based on tissue types from inflammatory and non-inflammatory breast cancer
A stromal gene signature associated with inflammatory breast cancer.
Specimen part, Disease, Race, Subject
View SamplesDuring chronic viral infection, the inflammatory function of CD4 T cells becomes gradually attenuated. Concurrently, Th1 cells progressively acquire the capacity to secrete the cytokine IL-10, a potent suppressor of antiviral T cell responses. To determine the transcriptional changes that underlie this T cell adaption process, we applied a single-cell RNA-sequencing approach and assessed the heterogeneity of IL-10-expressing CD4 T cells during chronic infection. Unexpectedly, our analyses revealed an IL-10-producing population with a robust Tfh-signature. Using IL-10 and IL-21 double-reporter mice, we further demonstrate that IL-10+IL-21+co-producing Tfh cells arise predominantly during chronic but not acute LCMV infection. Importantly, depletion of IL-10+IL-21+co-producing CD4 T cells or deletion of Il10 specifically in Tfh cells resulted in impaired humoral immunity and viral control. Mechanistically, B cell-intrinsic IL-10 signaling was required for sustaining germinal center reactions. Lastly, we demonstrate that IL-27 and type I IFNs differentially regulate the formation of this protective IL-10-producing Tfh subset. Thus, our findings elucidate a critical role for Tfh-derived IL-10 in promoting humoral immunity during persistent viral infection. Overall design: One sample prepared using 10x Genomics Chromium platform
Single-cell RNA sequencing unveils an IL-10-producing helper subset that sustains humoral immunity during persistent infection.
Specimen part, Subject, Time
View Samples