Toll-Like Receptor-mediated Innate Immune Functions of Rodent Microglia Ex vivo

AbstractThe intestinal epithelium plays a variety of roles including providing an effective physical barrier and innate immune protection against infection. Two-dimensional models of the intestinal epithelium, 2D enteroids, are a valuable resource to investigate intestinal cell biology and innate immune functions and are suitable for high throughput studies of paracellular transport and epithelial integrity. We have developed a chicken 2D enteroid model that recapitulates all major differentiated cell lineages, including enterocytes, Paneth cells, Goblet cells, enteroendocrine cells and leukocytes, and self-organises into an epithelial and mesenchymal sub-layer. Functional studies demonstrated the 2D enteroids formed a tight cell layer with minimal paracellular flux and a robust epithelial integrity, which was maintained or rescued following damage. The 2D enteroids were also able to demonstrate appropriate innate immune responses following exposure to bacterial endotoxins, from Salmonella enterica serotype Typhimurium and Bacillus subtilis. Frozen 2D enteroids cells when thawed were comparable to freshly isolated cells. The chicken 2D enteroids provide a useful ex vivo model to study intestinal cell biology and innate immune function, and have potential uses in screening of nutritional supplements, pharmaceuticals, and bioactive compounds.

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MyD88-Dependent Responses Involving Toll-Like Receptor 2 Are Important for Protection and Clearance of Legionella pneumophila in a Mouse Model of Legionnaires' Disease

Infection and Immunity ◽

10.1128/iai.02049-05 ◽

2006 ◽

Vol 74 (6) ◽

pp. 3325-3333 ◽

Cited By ~ 90

Author(s):

Kristina A. Archer ◽

Craig R. Roy

Keyword(s):

Pattern Recognition ◽

Bacterial Growth ◽

Legionella Pneumophila ◽

Ex Vivo ◽

Innate Immune ◽

Toll Like Receptor ◽

Littermate Control ◽

Legionnaires Disease ◽

Deficient Mice

ABSTRACT Legionella pneumophila is a gram-negative facultative intracellular parasite of macrophages. Although L. pneumophila is the causative agent of a severe pneumonia known as Legionnaires' disease, it is likely that most infections caused by this organism are cleared by the host innate immune system. It is predicted that host pattern recognition proteins belonging to the Toll-like receptor (TLR) family are involved in the protective innate immune responses. We examined the role of TLR-mediated responses in L. pneumophila detection and clearance using genetically altered mouse hosts in which the macrophages are permissive for L. pneumophila intracellular replication. Our data demonstrate that cytokine production by bone marrow-derived macrophages (BMMs) in response to L. pneumophila infection requires the TLR adapter protein MyD88 and is reduced in the absence of TLR2 but not in the absence of TLR4. Bacterial growth ex vivo in BMMs from MyD88-deficient mice was not enhanced compared to bacterial growth ex vivo in BMMs from heterozygous littermate controls. Wild-type mice were able to clear L. pneumophila from the lung, whereas respiratory infection of MyD88-deficient mice caused death that resulted from robust bacterial replication and dissemination. In contrast to an infection with virulent L. pneumophila, MyD88-deficient mice were able to clear infections with L. pneumophila dotA mutants, indicating that MyD88-independent responses in the lung are sufficient to clear bacteria that are unable to replicate intracellularly. In vivo growth of L. pneumophila was enhanced in the lungs of TLR2-deficient mice, which resulted in a delay in bacterial clearance. No significant differences were observed in the growth and clearance of L. pneumophila in the lungs of TLR4-deficient mice and heterozygous littermate control mice. Our data indicate that MyD88 is crucial for eliciting a protective innate immune response against virulent L. pneumophila and that TLR2 is one of the pattern recognition receptors involved in initiating this MyD88-dependent response.

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Toll- like receptor-2 mediates local innate immune response against Trypanosoma cruzi in ex vivo infected human placental chorionic villi explants

Placenta ◽

10.1016/j.placenta.2017.10.005 ◽

2017 ◽

Vol 60 ◽

pp. 40-46 ◽

Cited By ~ 11

Author(s):

Christian Castillo ◽

Lorena Muñoz ◽

Ileana Carrillo ◽

Ana Liempi ◽

Lisvaneth Medina ◽

...

Keyword(s):

Immune Response ◽

Trypanosoma Cruzi ◽

Innate Immune Response ◽

Ex Vivo ◽

Innate Immune ◽

Toll Like Receptor ◽

Chorionic Villi ◽

Toll Like Receptor 2

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Novel Innate Immune Functions Revealed by Dynamic, Real-Time Live Imaging of Bacterial Infections

Critical Reviews™ in Immunology ◽

10.1615/critrevimmunol.v30.i2.10 ◽

2010 ◽

Vol 30 (2) ◽

pp. 107-117 ◽

Cited By ~ 4

Author(s):

Keira Melican ◽

Jorrit Boekel ◽

Monica Ryden-Aulin ◽

Agneta Richter-Dahlfors

Keyword(s):

Real Time ◽

Bacterial Infections ◽

Live Imaging ◽

Innate Immune ◽

Immune Functions

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Faculty Opinions recommendation of Toll-like receptor 9 mediates innate immune activation by the malaria pigment hemozoin.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1023167.266680 ◽

2005 ◽

Author(s):

Ricardo Gazzinelli

Keyword(s):

Immune Activation ◽

Innate Immune ◽

Toll Like Receptor ◽

Innate Immune Activation ◽

Malaria Pigment

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Faculty Opinions recommendation of Toll-like receptor 1 polymorphisms affect innate immune responses and outcomes in sepsis.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1123124.580249 ◽

2008 ◽

Author(s):

Joseph Mizgerd

Keyword(s):

Immune Responses ◽

Innate Immune ◽

Innate Immune Responses ◽

Toll Like Receptor

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Toll-like receptor 4-mediated cytokine synthesis and post-stroke depressive symptoms

Translational Psychiatry ◽

10.1038/s41398-021-01359-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Michal Korostynski ◽

Dzesika Hoinkis ◽

Marcin Piechota ◽

Slawomir Golda ◽

Joanna Pera ◽

...

Keyword(s):

Gene Expression ◽

Depressive Symptoms ◽

Ex Vivo ◽

Toll Like Receptor ◽

Toll Like Receptor 4 ◽

Post Stroke ◽

Cytokines And Chemokines ◽

Patient Health ◽

Post Stroke Depression ◽

Cytokine Synthesis

AbstractAltered cytokine synthesis thought to contribute to the pathophysiology of post-stroke depression (PSD). Toll-like receptor 4 (TLR4) is a master regulator of innate immunity. The aim of this study was to explore the putative association between TLR4-mediated cytokine synthesis and subsequent symptoms of PSD. In total, 262 patients with ischemic stroke and without a history of PSD were included. Depressive symptoms were assessed using the Patient Health Questionnaire-9 in 170 patients on Day 8 and in 146 at 3 months after stroke. Blood samples taken on Day 3 after stroke were stimulated ex vivo with lipopolysaccharide (LPS). Ex vivo synthesized cytokines (TNFα, IP-10, IL-1β, IL-6, IL-8, IL-10, and IL-12p70) and circulating cytokines (TNFα, IL-6, sIL-6R, and IL-1ra) were measured using the enzyme-linked immunoassay or cytometric method. RNA sequencing was used to determine the gene expression profile of LPS-induced cytokines and chemokines. LPS-induced cytokine synthesis and the gene expression of TLR4-dependent cytokines and chemokines did not differ between patients with and without greater depressive symptoms. The plasma level of IL-6, but not TNFα, sIL-6R, and IL-1ra, was higher in patients who developed depressive symptoms at 3 months after stroke (median: 4.7 vs 3.4 pg/mL, P = 0.06). Plasma IL-6 predicted the severity of depressive symptoms at 3 months after stroke (β = 0.42, P = 0.03). In conclusion, TLR4-dependent cytokine synthesis was not associated with greater post-stroke depressive symptoms in this study. Circulating IL-6 might be associated with depressive symptoms occurring at 3 months after stroke.

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Human Immunodeficiency Virus Infection Alters Tumor Necrosis Factor Alpha Production via Toll-Like Receptor-Dependent Pathways in Alveolar Macrophages and U1 Cells

Journal of Virology ◽

10.1128/jvi.00362-08 ◽

2008 ◽

Vol 82 (16) ◽

pp. 7790-7798 ◽

Cited By ~ 26

Author(s):

Marlynne Q. Nicol ◽

Jean-Marie Mathys ◽

Albertina Pereira ◽

Kevin Ollington ◽

Michael H. Ieong ◽

...

Keyword(s):

Tumor Necrosis Factor ◽

Tumor Necrosis ◽

Innate Immune ◽

Hiv Positive ◽

Toll Like Receptor ◽

Necrosis Factor Alpha ◽

Tnf Α ◽

Immunodeficiency Virus ◽

Factor Alpha ◽

Necrosis Factor

ABSTRACT Human immunodeficiency virus (HIV)-positive persons are predisposed to pulmonary infections, even after receiving effective highly active antiretroviral therapy. The reasons for this are unclear but may involve changes in innate immune function. HIV type 1 infection of macrophages impairs effector functions, including cytokine production. We observed decreased constitutive tumor necrosis factor alpha (TNF-α) concentrations and increased soluble tumor necrosis factor receptor type II (sTNFRII) in bronchoalveolar lavage fluid samples from HIV-positive subjects compared to healthy controls. Moreover, net proinflammatory TNF-α activity, as measured by the TNF-α/sTNFRII ratio, decreased as HIV-related disease progressed, as manifested by decreasing CD4 cell count and increasing HIV RNA (viral load). Since TNF-α is an important component of the innate immune system and is produced upon activation of Toll-like receptor (TLR) pathways, we hypothesized that the mechanism associated with deficient TNF-α production in the lung involved altered TLR expression or a deficit in the TLR signaling cascade. We found decreased Toll-like receptor 1 (TLR1) and TLR4 surface expression in HIV-infected U1 monocytic cells compared to the uninfected parental U937 cell line and decreased TLR message in alveolar macrophages (AMs) from HIV-positive subjects. In addition, stimulation with TLR1/2 ligand (Pam3Cys) or TLR4 ligand (lipopolysaccharide) resulted in decreased intracellular phosphorylated extracellular signal-regulated kinase and subsequent decreased transcription and expression of TNF-α in U1 cells compared to U937 cells. AMs from HIV-positive subjects also showed decreased TNF-α production in response to these TLR2 and TLR4 ligands. We postulate that HIV infection alters expression of TLRs with subsequent changes in mitogen-activated protein kinase signaling and cytokine production that ultimately leads to deficiencies of innate immune responses that predispose HIV-positive subjects to infection.

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Effects of spaceflight on innate immune function and antioxidant gene expression

Journal of Applied Physiology ◽

10.1152/japplphysiol.91361.2008 ◽

2009 ◽

Vol 106 (6) ◽

pp. 1935-1942 ◽

Cited By ~ 92

Author(s):

Farnaz P. Baqai ◽

Daila S. Gridley ◽

James M. Slater ◽

Xian Luo-Owen ◽

Louis S. Stodieck ◽

...

Keyword(s):

Space Shuttle ◽

Ex Vivo ◽

Innate Immune ◽

Oxygen Species ◽

Bacterial Product ◽

Th1 Response ◽

Antioxidant Gene ◽

Tnf Α ◽

Antioxidant Gene Expression ◽

Cell Mitogen

Spaceflight conditions have a significant impact on a number of physiological functions due to psychological stress, radiation, and reduced gravity. To explore the effect of the flight environment on immunity, C57BL/6NTac mice were flown on a 13-day space shuttle mission (STS-118). In response to flight, animals had a reduction in liver, spleen, and thymus masses compared with ground (GRD) controls ( P < 0.005). Splenic lymphocyte, monocyte/macrophage, and granulocyte counts were significantly reduced in the flight (FLT) mice ( P < 0.05). Although spontaneous blastogenesis of splenocytes in FLT mice was increased, response to lipopolysaccharide (LPS), a B-cell mitogen derived from Escherichia coli, was decreased compared with GRD mice ( P < 0.05). Secretion of IL-6 and IL-10, but not TNF-α, by LPS-stimulated splenocytes was increased in FLT mice ( P < 0.05). Finally, many of the genes responsible for scavenging reactive oxygen species were upregulated after flight. These data indicate that exposure to the spaceflight environment can increase anti-inflammatory mechanisms and change the ex vivo response to LPS, a bacterial product associated with septic shock and a prominent Th1 response.

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