scholarly journals Mouse primary microglia respond differently to LPS and poly(I:C) in vitro

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yingbo He ◽  
Natalie Taylor ◽  
Xiang Yao ◽  
Anindya Bhattacharya
Keyword(s):  
Microglial Activation ◽  
Poly I:C ◽  
Type I ◽  
Primary Microglia ◽  
Viral Dsrna ◽  
Functional Differences ◽  
Genome Wide ◽  
Gene Level ◽  
Signal Cascades

AbstractMicroglia, CNS resident innate immune cells, respond strongly to activation of TLR3 and TLR4, which recognize viral dsRNA poly(I:C) and bacterial endotoxin LPS, respectively. However, few studies have thoroughly and parallelly compared functional phenotypes and downstream mechanisms between LPS- and poly(I:C)-exposed primary microglia. Here, we investigated the responses of mouse primary microglia upon LPS and poly(I:C) stimulation by detecting various phenotypes ranging from morphology, proliferation, secretion, chemotaxis, to phagocytosis. Furthermore, we explored their sequential gene expression and the downstream signal cascades. Interestingly, we found that the microglial activation pattern induced by LPS was distinguished from that induced by poly(I:C). Regarding microglial morphology, LPS caused an ameboid-like shape while poly(I:C) induced a bushy shape. Microglial proliferation was also facilitated by LPS but not by poly(I:C). In addition, LPS and poly(I:C) modulated microglial chemotaxis and phagocytosis differently. Furthermore, genome-wide analysis provided gene-level support to these functional differences, which may be associated with NF-κb and type I interferon pathways. Last, LPS- and poly(I:C)-activated microglia mediated neurotoxicity in a co-culture system. This study extends our understanding of TLR roles in microglia and provides insights into selecting proper inflammatory microglial models, which may facilitate identification of new targets for therapeutic application.

scholarly journals Enhancing innate antiviral immune responses in rainbow trout by double stranded RNA delivered with cationic phytoglycogen nanoparticles

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Tamiru N. Alkie ◽  
Jondavid de Jong ◽  
Kristof Jenik ◽  
Karl M. Klinger ◽  
Stephanie J. DeWitte-Orr
Keyword(s):  
Rainbow Trout ◽  
Immune Responses ◽  
Cell Line ◽  
Culture Conditions ◽  
Type I Interferons ◽  
Poly I:C ◽  
Synthetic Analogue ◽  
Type I ◽  
Viral Dsrna

Abstract Innate immunity is induced when pathogen-associated molecular patterns (PAMPs) bind host pattern recognition receptors (PRRs). Polyinosinic:polycytidylic acid [poly(I:C)] is a synthetic analogue of viral dsRNA that acts as a PAMP, inducing type I interferons (IFNs) in vertebrates. In the present study, the immunostimulatory effects of high molecular weight (HMW) poly(I:C) in rainbow trout cells were measured when bound to a cationic phytoglycogen nanoparticle (Nano-HMW). The physical characteristics of the nanoparticle itself, when bound to different lengths of dsRNA and when cell associated was evaluated. Optimal concentration and timing for innate immune stimulation was measured using the RTG-P1 reporter cell line. The immunostimulatory effects of HMW poly (I:C) was compared to Nano-HMW in vitro using the RTgutGC cell line cultured in a conventional monolayer or a transwell culture system. The ability of an activated intestinal epithelium to transmit an antiviral signal to macrophages was evaluated using a co-culture of RTgutGC cells and RTSll (a monocyte/macrophage cell). In all culture conditions, Nano-HMW was a more effective inducer of IFN-related antiviral immune responses compared to HMW poly (I:C) alone. This study introduces the use of cationic phytoglycogen nanoparticles as a novel delivery system for immunomodulatory molecules to enhance immune responses in aquatic vertebrates.

scholarly journals Analysis of Apoptosis of Memory T Cells and Dendritic Cells during the Early Stages of Viral Infection or Exposure to Toll-Like Receptor Agonists

2010 ◽  
Vol 84 (10) ◽  
pp. 4866-4877 ◽  
Author(s):  
Kapil Bahl ◽  
Anette Hüebner ◽  
Roger J. Davis ◽  
Raymond M. Welsh
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Ex Vivo ◽  
Annexin V ◽  
Poly I:C ◽  
Type I ◽  
Memory T Cell ◽  
Lcmv Infection

ABSTRACT Profound type I interferon (IFN-I)-dependent attrition of memory CD8 and CD4 T cells occurs early during many infections. It is dramatic at 2 to 4 days following lymphocytic choriomeningitis virus (LCMV) infection of mice and can be elicited by the IFN-inducing Toll receptor agonist poly(I:C). We show that this attrition occurs in many organs, indicating that it is due to T cell loss rather than redistribution. This loss correlated with elevated intracellular staining of T cells ex vivo for activated caspases but with only low levels of ex vivo staining with annexin V, probably due to the rapid clearance of apoptotic cells in vivo. Instead, a high frequency of annexin V-reactive CD8α+ dendritic cells (DCs), which are known to be highly phagocytic, accumulated in the spleen as the memory T cell populations disappeared. After short in vitro incubation, memory phenotype T cells isolated from LCMV-infected mice (day 3) or mice treated with poly(I:C) (12 h) displayed substantial DNA fragmentation, as detected by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) assay, compared to T cells isolated from uninfected mice, indicating a role for apoptosis in the memory T cell attrition. This apoptosis of memory CD8 T cells early during LCMV infection was reduced in mice lacking the proapoptotic molecule Bim. Evidence is presented showing that high levels of T cell attrition, as found in young mice, correlate with reduced immunodomination by cross-reactive memory cells.

scholarly journals Vaccinia Virus-Mediated Inhibition of Type I Interferon Responses Is a Multifactorial Process Involving the Soluble Type I Interferon Receptor B18 and Intracellular Components

2008 ◽  
Vol 83 (4) ◽  
pp. 1563-1571 ◽  
Author(s):  
Zoe Waibler ◽  
Martina Anzaghe ◽  
Theresa Frenz ◽  
Astrid Schwantes ◽  
Christopher Pöhlmann ◽  
...  
Keyword(s):  
Vaccinia Virus ◽  
Type I Interferon ◽  
Poly I:C ◽  
Host Responses ◽  
Type I ◽  
Immune Modulators ◽  
Modified Vaccinia Virus Ankara ◽  
Multistep Process ◽  
Interferon Responses

ABSTRACT Poxviruses such as virulent vaccinia virus (VACV) strain Western Reserve encode a broad range of immune modulators that interfere with host responses to infection. Upon more than 570 in vitro passages in chicken embryo fibroblasts (CEF), chorioallantois VACV Ankara (CVA) accumulated mutations that resulted in highly attenuated modified vaccinia virus Ankara (MVA). MVA infection of mice and of dendritic cells (DC) induced significant type I interferon (IFN) responses, whereas infection with VACV alone or in combination with MVA did not. These results implied that VACV expressed an IFN inhibitor(s) that was functionally deleted in MVA. To further characterize the IFN inhibitor(s), infection experiments were carried out with CVA strains isolated after 152 (CVA152) and 386 CEF passages (CVA386). Interestingly, neither CVA152 nor CVA386 induced IFN-α, whereas the latter variant did induce IFN-β. This pattern suggested a consecutive loss of inhibitors during MVA attenuation. Similar to supernatants of VACV- and CVA152-infected DC cultures, recombinantly expressed soluble IFN decoy receptor B18, which is encoded in the VACV genome, inhibited MVA-induced IFN-α but not IFN-β. In the same direction, a B18R-deficient VACV variant triggered only IFN-α, confirming B18 as the soluble IFN-α inhibitor. Interestingly, VACV infection inhibited IFN responses induced by a multitude of different stimuli, including oligodeoxynucleotides containing CpG motifs, poly(I:C), and vesicular stomatitis virus. Collectively, the data presented show that VACV-mediated IFN inhibition is a multistep process involving secreted factors such as B18 plus intracellular components that cooperate to efficiently shut off systemic IFN-α and IFN-β responses.

scholarly journals ICSBP Is Essential for the Development of Mouse Type I Interferon-producing Cells and for the Generation and Activation of CD8α+ Dendritic Cells

2002 ◽  
Vol 196 (11) ◽  
pp. 1415-1425 ◽  
Author(s):  
Giovanna Schiavoni ◽  
Fabrizio Mattei ◽  
Paola Sestili ◽  
Paola Borghi ◽  
Massimo Venditti ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Consensus Sequence ◽  
Critical Role ◽  
Myeloid Cell ◽  
Poly I:C ◽  
Intercellular Adhesion Molecule ◽  
Type I ◽  
Mrna Levels ◽  
Virus Infections

Interferon (IFN) consensus sequence-binding protein (ICSBP) is a transcription factor playing a critical role in the regulation of lineage commitment, especially in myeloid cell differentiation. In this study, we have characterized the phenotype and activation pattern of subsets of dendritic cells (DCs) in ICSBP−/− mice. Remarkably, the recently identified mouse IFN-producing cells (mIPCs) were absent in all lymphoid organs from ICSBP−/− mice, as revealed by lack of CD11clowB220+Ly6C+CD11b− cells. In parallel, CD11c+ cells isolated from ICSBP−/− spleens were unable to produce type I IFNs in response to viral stimulation. ICSBP−/− mice also displayed a marked reduction of the DC subset expressing the CD8α marker (CD8α+ DCs) in spleen, lymph nodes, and thymus. Moreover, ICSBP−/− CD8α+ DCs exhibited a markedly impaired phenotype when compared with WT DCs. They expressed very low levels of costimulatory molecules (intercellular adhesion molecule [ICAM]-1, CD40, CD80, CD86) and of the T cell area-homing chemokine receptor CCR7, whereas they showed higher levels of CCR2 and CCR6, as revealed by reverse transcription PCR. In addition, these cells were unable to undergo full phenotypic activation upon in vitro culture in presence of maturation stimuli such as lipopolysaccharide or poly (I:C), which paralleled with lack of Toll-like receptor (TLR)3 mRNA expression. Finally, cytokine expression pattern was also altered in ICSBP−/− DCs, as they did not express interleukin (IL)-12p40 or IL-15, but they displayed detectable IL-4 mRNA levels. On the whole, these results indicate that ICSBP is a crucial factor in the regulation of two possibly linked processes: (a) the development and activity of mIPCs, whose lack in ICSBP−/− mice may explain their high susceptibility to virus infections; (b) the generation and activation of CD8α+ DCs, whose impairment in ICSBP−/− mice can be responsible for the defective generation of a Th1 type of immune response.

scholarly journals Type I interferon signaling mediates Mycobacterium tuberculosis–induced macrophage death

2020 ◽  
Vol 218 (2) ◽  
Author(s):  
Li Zhang ◽  
Xiuju Jiang ◽  
Daniel Pfau ◽  
Yan Ling ◽  
Carl F. Nathan
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Critical Role ◽  
Type I ◽  
Type I Ifn ◽  
Paracrine Signaling ◽  
Type I Ifns ◽  
Genome Wide ◽  
Mouse Macrophages ◽  
Definition Of

Macrophages help defend the host against Mycobacterium tuberculosis (Mtb), the major cause of tuberculosis (TB). Once phagocytized, Mtb resists killing by macrophages, replicates inside them, and leads to their death, releasing Mtb that can infect other cells. We found that the death of Mtb-infected mouse macrophages in vitro does not appear to proceed by a currently known pathway. Through genome-wide CRISPR-Cas9 screening, we identified a critical role for autocrine or paracrine signaling by macrophage-derived type I IFNs in the death of Mtb-infected macrophages in vitro, and blockade of type I IFN signaling augmented the effect of rifampin, a first-line TB drug, in Mtb-infected mice. Further definition of the pathway of type I IFN–mediated macrophage death may allow for host-directed therapy of TB that is more selective than systemic blockade of type I IFN signaling.

scholarly journals The Response of Tissue Mast Cells to TLR3 Ligand Poly(I:C) Treatment

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Piotr Witczak ◽  
Ewa Brzezińska-Błaszczyk ◽  
Justyna Agier
Keyword(s):  
Mast Cells ◽  
Bacterial Infections ◽  
Lymphatic Vessels ◽  
Poly I:C ◽  
Type I ◽  
Viral Dsrna ◽  
Mhc I ◽  
Antiviral Immune Response ◽  
Cellular Antiviral Response

Mast cells (MCs) are found mainly at the anatomical sites exposed to the external environment; thus, they are localized close to blood vessels, lymphatic vessels, and a multitude of immune cells. Moreover, those cells can recognize invading pathogens through a range of surface molecules known as pathogen recognition receptors (PRRs), mainly Toll-like receptors (TLRs). MCs are extensively engaged in the control and clearance of bacterial infections, but much less is known about their contribution to antiviral host response as well as pathomechanisms of virus-induced diseases. In the study, we employed in vivo differentiated mature tissue mast cells freshly isolated from rat peritoneal cavity. Here, we demonstrated that rat peritoneal mast cells (rPMCs) express viral dsRNA-specific TLR3 molecule (intracellularly and on the cell surface) as well as other proteins associated with cellular antiviral response: IRF3, type I and II IFN receptors, and MHC I. We found that exposure of rPMCs to viral dsRNA mimic, i.e., poly(I:C), induced transient upregulation of surface TLR3 (while temporarily decreased TLR3 intracellular expression), type II IFN receptor, and MHC I. TLR3 ligand-stimulated rPMCs did not degranulate but generated and/or released type I IFNs (IFN-α and IFNβ) as well as proinflammatory lipid mediators (cysLTs), cytokines (TNF, IL-1β), and chemokines (CCL3, CXCL8). We documented that rPMC priming with poly(I:C) did not affect FcεRI-dependent degranulation. However, their costimulation with TLR3 agonist and anti-IgE led to a significant increase in cysLT and TNF secretion. Our findings confirm that MCs may serve as active participants in the antiviral immune response. Presented data on modulated FcεRI-mediated MC secretion of mediators upon poly(I:C) treatment suggests that dsRNA-type virus infection could influence the severity of allergic reactions.

scholarly journals Strain and lineage-level methylome heterogeneity in the multi-drug resistant pathogenic Escherichia coli ST101 clone

2020 ◽  
Author(s):  
Melinda M. Ashcroft ◽  
Brian M. Forde ◽  
Minh-Duy Phan ◽  
Kate M. Peters ◽  
Leah W. Roberts ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Dna Methylation ◽  
Carbapenem Resistance ◽  
Mobile Genetic Elements ◽  
Dna Methyltransferases ◽  
Type I ◽  
E Coli ◽  
Genetic Elements ◽  
Functional Differences ◽  
Genome Wide

AbstractEscherichia coli Sequence Type (ST)101 is an emerging, multi-drug resistant lineage associated with carbapenem resistance. We recently completed a comprehensive genomics study on mobile genetic elements (MGEs) and their role in blaNDM-1 dissemination within the ST101 lineage. DNA methyltransferases (MTases) are also frequently associated with MGEs, with DNA methylation guiding numerous biological processes including genomic defence against foreign DNA and regulation of gene expression. The availability of Pacific Biosciences Single Molecule Real Time Sequencing data for seven ST101 strains enabled us to investigate the role of DNA methylation on a genome-wide scale (methylome). We defined the methylome of two complete (MS6192 and MS6193) and five draft (MS6194, MS6201, MS6203, MS6204, MS6207) ST101 genomes. Our analysis identified 14 putative MTases and eight N6-methyladenine DNA recognition sites, with one site that has not been described previously. Furthermore, we identified a Type I MTase encoded within a Transposon 7-like Transposon and show its acquisition leads to differences in the methylome between two almost identical isolates. Genomic comparisons with 13 previously published ST101 draft genomes identified variations in MTase distribution, consistent with MGE differences between genomes, highlighting the diversity of active MTases within strains of a single E. coli lineage. It is well established that MGEs can contribute to the evolution of E. coli due to their virulence and resistance gene repertoires. This study emphasises the potential for mobile genetic elements to also enable highly similar bacterial strains to rapidly acquire genome-wide functional differences via changes to the methylome.Impact StatementEscherichia coli ST101 is an emerging human pathogen frequently associated with carbapenem resistance. E. coli ST101 strains carry numerous mobile genetic elements that encode virulence determinants, antimicrobial resistance, and DNA methyltransferases (MTases). In this study we provide the first comprehensive analysis of the genome-wide complement of DNA methylation (methylome) in seven E. coli ST101 genomes. We identified a Transposon carrying a Type I restriction modification system that may lead to functional differences between two almost identical genomes and showed how small recombination events at a single genomic region can lead to global methylome changes across the lineage. We also showed that the distribution of MTases throughout the ST101 lineage was consistent with the presence or absence of mobile genetic elements on which they are encoded. This study shows the diversity of MTases within a single bacterial lineage and shows how strain and lineage-specific methylomes may drive host adaptation.Data SummarySequence data including reads, assemblies and motif summaries have previously been submitted to the National Center for Biotechnology Information (https://www.ncbi.nlm.nih.gov) under the BioProject Accessions: PRJNA580334, PRJNA580336, PRJNA580337, PRJNA580338, PRJNA580339, PRJNA580341 and PRJNA580340 for MS6192, MS6193, MS6194, MS6201, MS6203, MS6204 and MS6207 respectively. All supporting data, code, accessions, and protocols have been provided within the article or through supplementary data files.

scholarly journals Variation in Genome-wide NF-kappaB RELA Binding Sites upon Microbial Stimuli and Identification of a Virus Response Profile

2018 ◽  
Author(s):  
Lisa Borghini ◽  
Jinhua Lu ◽  
Martin Hibberd ◽  
Sonia Davila
Keyword(s):  
Binding Sites ◽  
Specific Activity ◽  
Adaptive Immune System ◽  
Poly I:C ◽  
Viral Dsrna ◽  
Expression Of Genes ◽  
Dna Binding Sites ◽  
Genome Wide ◽  
Pathogen Recognition Receptors ◽  
Nf Kappab

AbstractNF-kB transcription factors are master regulators of the innate immune response. Activated downstream of pathogen recognition receptors, they regulate the expression of genes to help fighting infections as well as recruiting the adaptive immune system. NF-kB responds to a wide variety of signals, but the processes by which stimulus-specificity is attained remain unclear. Here, we characterized the response of one NF-kB member, RELA, to four stimuli mimicking infection in human nasopharyngeal epithelial cells. Comparing genome-wide RELA binding, we observed stimulus-specific sites, although most sites overlapped across stimuli. Specifically, the response to Poly I:C – mimicking viral dsRNA and signalling through TLR3 – induced a distinct RELA profile, binding in the vicinity of antiviral genes and correlating with corresponding gene expression. This group of binding sites was also enriched in Interferon Regulatory Factor (IRF) motifs and showed overlapping with IRFs binding sites. A novel NF-kB target, OASL was further validated and showed TLR3-specific activation. This work showed that some RELA DNA binding sites varied in activation response following different stimulations and that interaction with more specialized factors could help achieve this stimulus-specific activity. Our data provide a genomic view of regulated host response to different pathogen stimuli.

scholarly journals Diosgenin Prevents Microglial Activation and Protects Dopaminergic Neurons from Lipopolysaccharide-Induced Neural Damage In Vitro and In Vivo

2021 ◽  
Vol 22 (19) ◽  
pp. 10361
Author(s):  
Shou-Lun Lee ◽  
Ssu-Chieh Tu ◽  
Ming-Yen Hsu ◽  
Ting-Yu Chin
Keyword(s):  
Dopaminergic Neurons ◽  
Dopaminergic Neuron ◽  
Microglial Activation ◽  
Neuroprotective Effect ◽  
Motor Dysfunction ◽  
Primary Microglia ◽  
Neural Damage ◽  
Age Related

Background: The prevention of age-related neurodegenerative disorders is an important issue in an aging society. Microglia-mediated neuroinflammation resulting in dopaminergic neuron loss may lead to the pathogenesis of Parkinson’s disease (PD). Lipopolysaccharide (LPS), an endotoxin, induces neuroinflammatory microglial activation, contributing to dopaminergic neuron damage. Diosgenin is a phytosteroid sapogenin with a wide spectrum of pharmacological activities, e.g., anti-inflammatory activity. However, the preventive effect of diosgenin on neuroinflammation is not clear. Thus, in this study, we further investigated the neuroprotective effect of diosgenin on LPS-induced neural damage in vitro and in vivo. Methods: For in vitro experiments, primary mesencephalic neuron-glia cultures and primary microglia cultures isolated from Sprague–Dawley rats were used. Cells were pretreated with diosgenin and then stimulated with LPS. The expression of proinflammatory cytokines or tyrosine hydroxylase (TH) in the cells was analyzed. In vivo, rats were fed a diet containing 0.1% (w/w) diosgenin for 4 weeks before being administered a unilateral substantia nigra (SN) injection of LPS. Four weeks after the LPS injection, the rats were assessed for lesion severity using the amphetamine-induced rotation test and TH immunohistochemistry. Results: Diosgenin pretreatment prevented LPS-induced neurite shortening in TH-positive neurons in mesencephalic neuron-glia cultures. In addition, pretreatment of primary microglia with diosgenin significantly reduced tumor necrosis factor-α (TNF-α) and inducible nitric oxide synthase (iNOS) expression. Moreover, diosgenin pretreatment significantly suppressed LPS-induced extracellular signal-regulated kinase (ERK) activation. In vivo, the intranigral injection of LPS in rats fed a diosgenin-containing diet significantly improved motor dysfunction and reduced TH expression in SN. Conclusion: These results support the effectiveness of diosgenin in protecting dopaminergic neurons from LPS-induced neuroinflammation.

scholarly journals Regulation of TRIF-mediated innate immune response by K27-linked polyubiquitination and deubiquitination

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Xin Wu ◽  
Caoqi Lei ◽  
Tian Xia ◽  
Xuan Zhong ◽  
Qing Yang ◽  
...  
Keyword(s):  
Immune Responses ◽  
Adaptor Protein ◽  
Innate Immune ◽  
Negative Regulator ◽  
Type I Interferons ◽  
Poly I:C ◽  
Type I ◽  
Innate Immune Responses

Abstract TIR domain-containing adaptor inducing interferon-β (TRIF) is an essential adaptor protein required for innate immune responses mediated by Toll-like receptor (TLR) 3- and TLR4. Here we identify USP19 as a negative regulator of TLR3/4-mediated signaling. USP19 deficiency increases the production of type I interferons (IFN) and proinflammatory cytokines induced by poly(I:C) or LPS in vitro and in vivo. Usp19-/- mice have more serious inflammation after poly(I:C) or LPS treatment, and are more susceptible to inflammatory damages and death following Salmonella typhimurium infection. Mechanistically, USP19 interacts with TRIF and catalyzes the removal of TRIF K27-linked polyubiquitin moieties, thereby impairing the recruitment of TRIF to TLR3/4. In addition, the RING E3 ubiquitin ligase complex Cullin-3-Rbx1-KCTD10 catalyzes K27-linked polyubiquitination of TRIF at K523, and deficiency of this complex inhibits TLR3/4-mediated innate immune signaling. Our findings thus reveal TRIF K27-linked polyubiquitination and deubiquitination as a critical regulatory mechanism of TLR3/4-mediated innate immune responses.

Sign in / Sign up

Export Citation Format

Share Document