scholarly journals Basolateral activation with TLR agonists induces polarized cytokine release and reduces barrier function in RPE in vitro

2020 ◽  
Author(s):  
Laura Terheyden ◽  
Johann Roider ◽  
Alexa Klettner
Keyword(s):  
Cell Viability ◽  
Barrier Function ◽  
Neuronal Cell ◽  
Poly I:C ◽  
Rpe Cells ◽  
Ussing Chambers ◽  
Tlr Agonists ◽  
Danger Signals ◽  
Polycytidylic Acid

Abstract Purpose Systemic inflammation may be of importance in the development of AMD. RPE cells can recognize danger signals with toll-like receptors (TLR) and may react in a pro-inflammatory manner. In this study, we evaluated the basal and apical secretions of TNFα, IL-6, and IL-1β in primary RPE cells and RPE/choroid explant cells under basolateral stimulation of TLR2, 3, and 4; the effects on barrier function; and their influence on neuronal cell viability. Methods RPE/choroid tissue explants were prepared from porcine eyes and cultivated in modified Ussing chambers; primary porcine RPE cells on transwell plates. Cells were basally stimulated with agonists Pam2CSK4 (Pam; TLR2), polyinosinic/polycytidylic acid (Poly I:C; TLR3), and lipopolysaccharide (LPS; TLR4) for 24 h. Supernatants were evaluated with ELISA for cytokines TNFα, IL-6, and IL-1β. Apical supernatants were applied to SHSY-5Y cells, and cell viability was evaluated in MTT assay. Barrier function was tested by measuring transepithelial electrical resistance (TER) and occludin immunostaining. Results None of the tested TLR agonists was toxic on RPE cells after 24 h of exposure. Unstimulated RPE cells secreted hardly any cytokines. Pam induced IL-6, IL-1ß, and TNFα on the basal and apical sides at all concentrations tested. Poly I:C induced IL-6 and TNFα primarily at the basal side at lower but on both sides at higher concentrations. LPS induced IL-6, IL-1ß, and TNFα apically and basally at all concentrations tested. In the RPE/choroid, a strong difference between apical and basal secretions could be found. IL-6 was constitutively secreted basally, but not apically, but was induced by all agonists on both sides. IL-1ß and TNFα alpha were strongly induced on the basal side by all agonists. TER was reduced by all agonists, with Pam and LPS being effective in all concentrations tested. Occludin expression was unaltered, but the distribution was influenced by the agonists, with a less distinct localization at the cell borders after treatment. None of the agonists or supernatants of treated RPE and RPE/choroid organ cultures exerted any effect on viability of SHSY-5Y cells. Conclusions Danger signals activating TLRs can induce polarized cytokine expression and contribute to the loss of barrier function in the RPE.

scholarly journals TLR3 activation increases chemokine expression in human fetal airway smooth muscle cells

2016 ◽  
Vol 310 (2) ◽  
pp. L202-L211 ◽  
Author(s):  
Arij Faksh ◽  
Rodney D. Britt ◽  
Elizabeth R. Vogel ◽  
Michael A. Thompson ◽  
Hitesh C. Pandya ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Respiratory Syncytial Virus ◽  
Signaling Pathways ◽  
Airway Smooth Muscle ◽  
Poly I:C ◽  
Airway Smooth Muscle Cells ◽  
Tlr Agonists ◽  
Polycytidylic Acid ◽  
Syncytial Virus

Viral infections, such as respiratory syncytial virus and rhinovirus, adversely affect neonatal and pediatric populations, resulting in significant lung morbidity, including acute asthma exacerbation. Studies in adults have demonstrated that human airway smooth muscle (ASM) cells modulate inflammation through their ability to secrete inflammatory cytokines and chemokines. The role of ASM in the developing airway during infection remains undefined. In our study, we used human fetal ASM cells as an in vitro model to examine the effect of Toll-like receptor (TLR) agonists on chemokine secretion. We found that fetal ASM express multiple TLRs, including TLR3 and TLR4, which are implicated in the pathogenesis of respiratory syncytial virus and rhinovirus infection. Cells were treated with TLR agonists, polyinosinic-polycytidylic acid [poly(I:C)] (TLR3 agonist), lipopolysaccharide (TLR4 agonist), or R848 (TLR7/8 agonist), and IL-8 and chemokine (C-C motif) ligand 5 (CCL5) secretion were evaluated. Interestingly, poly(I:C), but neither lipopolysaccharide nor R848, increased IL-8 and chemokine (C-C motif) ligand 5 secretion. Examination of signaling pathways suggested that the poly(I:C) effects in fetal ASM involve TLR and ERK signaling, in addition to another major inflammatory pathway, NF-κB. Moreover, there are variations between fetal and adult ASM with respect to poly(I:C) effects on signaling pathways. Pharmacological inhibition suggested that ERK pathways mediate poly(I:C) effects. Overall, our data show that poly(I:C) initiates activation of proinflammatory pathways in developing ASM, which may contribute to immune responses to infection and exacerbation of asthma.

scholarly journals A Higher Proportion of Eicosapentaenoic Acid (EPA) When Combined with Docosahexaenoic Acid (DHA) in Omega-3 Dietary Supplements Provides Higher Antioxidant Effects in Human Retinal Cells

Antioxidants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 828 ◽  
Author(s):  
Manuel Saenz de Viteri ◽  
María Hernandez ◽  
Valentina Bilbao-Malavé ◽  
Patricia Fernandez-Robredo ◽  
Jorge González-Zamora ◽  
...  
Keyword(s):  
Docosahexaenoic Acid ◽  
Eicosapentaenoic Acid ◽  
Cell Viability ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Ethyl Esters ◽  
Omega 3 ◽  
Rpe Cells ◽  
Antioxidant Effects

Retinal pigment epithelium (RPE) is a key regulator of retinal function and is directly related to the transport, delivery, and metabolism of long-chain n-3 polyunsaturated fatty acids (n3-PUFA), in the retina. Due to their functions and location, RPE cells are constantly exposed to oxidative stress. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have shown to have antioxidant effects by different mechanisms. For this reason, we designed an in vitro study to compare 10 formulations of DHA and EPA supplements from different origins and combined in different proportions, evaluating their effect on cell viability, cell proliferation, reactive oxygen species production, and cell migration using ARPE-19 cells. Furthermore, we assessed their ability to rescue RPE cells from the oxidative conditions seen in diabetic retinopathy. Our results showed that the different formulations of n3-PUFAs have a beneficial effect on cell viability and proliferation and are able to restore oxidative induced RPE damage. We observed that the n3-PUFA provided different results alone or combined in the same supplement. When combined, the best results were obtained in formulations that included a higher proportion of EPA than DHA. Moreover, n3-PUFA in the form of ethyl-esters had a worse performance when compared with triglycerides or phospholipid based formulations.

scholarly journals In Vitro Antioxidant Capacity and Neuronal Cell Toxicity of Roots of Ostericum koreanum Maximowicz

2011 ◽  
Vol 8 (3) ◽  
pp. 1451-1455
Author(s):  
Ramalingam Mahesh ◽  
Hyo Won Jung ◽  
Jun Hong Park ◽  
Yong-Ki Park
Keyword(s):  
Cell Viability ◽  
Ethyl Acetate ◽  
Antioxidant Activities ◽  
Radical Scavenging ◽  
Neuronal Cell ◽  
Ethyl Acetate Fraction ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Ostericum Koreanum

Ostericum koreanummaximowicz (Umbelliferae), a medicinal herb in Korean Oriental Medicine, has been applied to treat cold, headache, neuralgia and arthralgia. The ethyl acetate fraction ofO. koreanumroot was subjected toin vitroantioxidant activity with different methods for free radical scavenging activities. In addition, the cell viability and nitric oxide release assays were performed here for the first time in neuroblastoma (Neuro-2a) cell cultures. Among all the tested methods, the ethyl acetate fraction was expressed very active, exhibiting a good Trolox equivalent values and IC50, comparable to that of the commercial antioxidants, Trolox and ascorbic acid, respectively. The results showed that there was a reduction of cell viability by the fraction in a concentration dependent manner. These results suggest thatO. koreanumshows good antioxidant activitiesin vitroby inhibiting free radicals. These findings provide a rationale for thein vivotesting. Also, the major constituents behind the antioxidant mechanisms of this fraction warrant further study.

scholarly journals Ethanol-Induced Lymphatic Endothelial Cell Permeability via MAP-Kinase Regulation

2021 ◽  
Author(s):  
Matthew Herrera ◽  
Patricia Molina ◽  
Flavia M. Souza-Smith
Keyword(s):  
Endothelial Cell ◽  
Cell Viability ◽  
Barrier Function ◽  
Protein Localization ◽  
Cell Monolayer ◽  
Lymphatic Endothelial Cell ◽  
Cell Permeability ◽  
Gene Expressions ◽  
Mapk Activation

Chronic alcohol alters the immune system enhancing the susceptibility to inflammation, bacterial, and viral infections in alcohol users. We have shown that alcohol causes increased permeability of mesenteric lymphatic vessels in alcohol fed rats. The mechanisms of alcohol-induced lymphatic leakage are unknown. Endothelial cell monolayer permeability is controlled by junctional proteins complexes called tight junctions (TJ) and adherens junctions (AJ), and each can be regulated by MAPK activation. We hypothesize that ethanol induces lymphatic endothelial cell (LEC) permeability via disruption of LEC TJ through MAPK activation. An in vitro model of rat LECs was used. Ethanol-supplemented medium was added at concentrations of 0, 25, and 50 mM to confluent cells. Resistance-based barrier function, transwell permeability, cell viability, TJ, AJ, and MAPK protein activity, TJ and AJ gene expressions, and the role of p38 MAPK in barrier function regulation were measured. Ethanol increased the permeability of LECs compared to controls that was not associated with decreased cell viability. LECs treated with 50 mM ethanol showed an increase in phosphorylated levels of p38. No significant changes in TJ and AJ gene or protein expressions were observed after ethanol treatment. p38 inhibition prevented ethanol-induced increases in permeability. These findings suggest that p38 may play a role in the regulation of ethanol-induced LEC permeability, but altered permeability may not be associated with decreased TJ or AJ protein expression. Further investigation into junctional protein localization is needed to better understand the effects of ethanol on lymphatic endothelial cell-to-cell contacts and hyperpermeability.

Di-2-ethylhexyl phthalate (DEHP) induces apoptosis of mouse HT22 hippocampal neuronal cells via oxidative stress

2020 ◽  
Vol 36 (11) ◽  
pp. 844-851
Author(s):  
Wei Tu ◽  
Weifeng Li ◽  
Xingen Zhu ◽  
Linlin Xu
Keyword(s):  
Oxidative Stress ◽  
Cell Viability ◽  
Neuronal Cell ◽  
Underlying Mechanism ◽  
Treated Group ◽  
Dependent Manner ◽  
Ht22 Cells ◽  
Protein Levels ◽  
Ethylhexyl Phthalate

Di-2-ethylhexyl phthalate (DEHP) has been widely used as a plasticizer in industry and can affect memory; however, the underlying mechanism remains unclear. In the present study, mouse HT22 cells, an immortalized hippocampal neuronal cell line, was utilized as an in vitro model. We showed that DEHP dramatically inhibited cell viability and increased lactate dehydrogenase (LDH) release from the cells in a dose-dependent manner, suggesting that DEHP could cause cytotoxicity of mouse HT22 cells. The protein levels of cleaved Caspase-8, cleaved Caspase-3, and Bax markedly increased in the DEHP-treated cells, whereas there was a significant decrease in the Bcl-2 protein level, implying that DEHP could induce apoptosis of mouse HT22 cells. DEHP exposure significantly increased the content of malondialdehyde, whereas it markedly decreased the level of glutathione and the activities of glutathione peroxidase and superoxide dismutase, suggesting that DEHP induced oxidative stress of the cells. Compared with the DEHP-treated group, the inhibition of cell viability and the release of LDH were rescued in the N-acetyl-l-cysteine plus DEHP group. Furthermore, inhibition of oxidative stress could rescue the induction of apoptosis by DEHP. Collectively, our results indicated that DEHP could induce apoptosis of mouse HT22 cells via oxidative stress.

TLR3-induced activation of mast cells modulates CD8+ T-cell recruitment

Blood ◽  
2005 ◽  
Vol 106 (3) ◽  
pp. 978-987 ◽  
Author(s):  
Zane Orinska ◽  
Elena Bulanova ◽  
Vadim Budagian ◽  
Martin Metz ◽  
Marcus Maurer ◽  
...  
Keyword(s):  
Mast Cell ◽  
T Cell ◽  
Mast Cells ◽  
Cd8 T Cell ◽  
Poly I:C ◽  
Cell Recruitment ◽  
Polycytidylic Acid ◽  
Peritoneal Mast Cells

AbstractMast cells play an important role in host defense against various pathogens, but their role in viral infection has not been clarified in detail. dsRNA, synthesized by various types of viruses and mimicked by polyinosinic-polycytidylic acid (poly(I:C)) is recognized by Toll-like receptor 3 (TLR3). In this study, we demonstrate that poly(I:C) injection in vivo potently stimulates peritoneal mast cells to up-regulate a number of different costimulatory molecules. Therefore, we examined the expression and the functional significance of TLR3 activation in mast cells. Mast cells express TLR3 on the cell surface and intracellularly. After stimulation of mast cells with poly(I:C) and Newcastle disease virus (NDV), TLR3 is phosphorylated and the expression of key antiviral response cytokines (interferon β, ISG15) and chemokines (IP10, RANTES) is upregulated. Interestingly, mast cells activated via TLR3-poly(I:C) potently stimulate CD8+ T-cell recruitment. Indeed, mast-cell–deficient mice (KitW/KitW-v) given an intraperitoneal injection of poly(I:C) show a decreased CD8+ T-cell recruitment, whereas granulocytes normally migrate to the peritoneal cavity. Mast-cell reconstitution of KitW/KitW-v mice normalizes the CD8+ T-cell influx. Thus, mast cells stimulated through engagement of TLR3 are potent regulators of CD8+ T-cell activities in vitro and in vivo.

In vitro effect of the Phoneutria nigriventer spider venom on cell viability, paracellular barrier function and transcellular transport in cultured cell lines

Toxicon ◽  
2005 ◽  
Vol 46 (2) ◽  
pp. 130-141 ◽  
Author(s):  
Luciana de Paula Le Sueur ◽  
Carla Beatriz Collares-Buzato ◽  
Evanguedes Kalapothakis ◽  
Maria Alice da Cruz-Höfling
Keyword(s):  
Cell Viability ◽  
Cell Lines ◽  
Barrier Function ◽  
Spider Venom ◽  
Transcellular Transport ◽  
Cultured Cell ◽  
Vitro Effect ◽  
Phoneutria Nigriventer

scholarly journals Chicken DDX1 Acts as an RNA Sensor to Mediate IFN-β Signaling Pathway Activation in Antiviral Innate Immunity

2021 ◽  
Vol 12 ◽  
Author(s):  
Zhenyu Lin ◽  
Jie Wang ◽  
Wenxian Zhu ◽  
Xiangyu Yu ◽  
Zhaofei Wang ◽  
...  
Keyword(s):  
Viral Infections ◽  
Rna Virus ◽  
Direct Interaction ◽  
Poly I:C ◽  
Polycytidylic Acid ◽  
Pulldown Assay ◽  
Pathway Activation ◽  
Viral Yield ◽  
Antiviral Innate Immunity

Chickens are the natural host of Newcastle disease virus (NDV) and avian influenza virus (AIV). The discovery that the RIG-I gene, the primary RNA virus pattern recognition receptor (PRR) in mammals, is naturally absent in chickens has directed attention to studies of chicken RNA PRRs and their functions in antiviral immune responses. Here, we identified Asp-Glu-Ala-Asp (DEAD)-box helicase 1 (DDX1) as an essential RNA virus PRR in chickens and investigated its functions in anti-RNA viral infections. The chDDX1 gene was cloned, and cross-species sequence alignment and phylogenetic tree analyses revealed high conservation of DDX1 among vertebrates. A quantitative RT-PCR showed that chDDX1 mRNA are widely expressed in different tissues in healthy chickens. In addition, chDDX1 was significantly upregulated after infection with AIV, NDV, or GFP-expressing vesicular stomatitis virus (VSV-GFP). Overexpression of chDDX1 in DF-1 cells induced the expression of IFN-β, IFN-stimulated genes (ISGs), and proinflammatory cytokines; it also inhibited NDV and VSV replications. The knockdown of chDDX1 increased the viral yield of NDV and VSV and decreased the production of IFN-β, which was induced by RNA analog polyinosinic-polycytidylic acid (poly[I:C]), by AIV, and by NDV. We used a chicken IRF7 (chIRF7) knockout DF-1 cell line in a series of experiments to demonstrate that chDDX1 activates IFN signaling via the chIRF7 pathway. Finally, an in-vitro pulldown assay showed a strong and direct interaction between poly(I:C) and the chDDX1 protein, indicating that chDDX1 may act as an RNA PRR during IFN activation. In brief, our results suggest that chDDX1 is an important mediator of IFN-β and is involved in RNA- and RNA virus-mediated chDDX1-IRF7-IFN-β signaling pathways.

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