Abstract 003: Direct and Indirect Effects of Prostaglandin E 2 and Its EP1/EP3 Receptors on Dendritic Cell Activation in Mice with L-NAME/High Salt-induced Hypertension

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Liang Xiao ◽  
Hana A Itani ◽  
Maria P Kraemer ◽  
Richard M Breyer ◽  
David G Harrison
Keyword(s):  
Cell Activation ◽  
Systolic Pressure ◽  
Adduct Formation ◽  
High Salt ◽  
Effector Memory ◽  
Prostaglandin E ◽  
Dendritic Cell Activation ◽  
Ep3 Receptor

We recently identified a pathway underlying immune activation in hypertension. Proteins oxidatively modified by reactive γ-ketoaldehydes (isoketals) accumulate in dendritic cells (DCs). These are immunogenic and lead to subsequent T lymphocytes activation. The local signals that stimulate DCs to accumulate isoketal adducts remain undefined. Prostaglandin E 2 (PGE 2 ) has been implicated in the inflammation associated with hypertension. We hypothesized that PGE 2 via its EP3 receptor contributes to DC activation in hypertension. EP3 -/- mice and wild type (WT) littermates were exposed to sequential hypertensive stimuli involving an initial 2-week exposure to the NOS inhibitor L-NAME (LN) in drinking water, a 2 week washout period, and a subsequent 4% high salt diet (HS) for 3 weeks. In WT mice, this protocol increased systolic pressure from 123±2 to 148±8 mmHg (p<0.05), and renal CD4 + and CD8 + effector memory T cells by 2 to 3 fold. This was associated with a striking accumulation of isoketal protein adducts in splenic DCs. However, the increases in blood pressure, renal T cell infiltration and DC isoketal formation were completely prevented in EP3 -/- mice. We further hypothesized that EP3 receptors contribute to oxidative stress production in the kidney. As measured by dihydroethidium with confocal microscopy, the LNHS protocol induced marked increases in superoxide production in WT mice, but not in EP3 -/- mice. To examine the direct effects of PGE 2 , splenic DCs were incubated with PGE 2 in vitro for 24 hours. PGE 2 dose-dependently increased isoketal-adduct formation in DCs (vehicle: 8.8±5.1% vs. 50 nM PGE 2 : 41.4±11.7%, p<0.05). Interestingly, this effect was not blocked by the EP3 receptor antagonist DG-041 (30 nM), but was completely prevented by the EP1 receptor blocker SC-51322 (20 μM). These data indicate both direct and indirect roles of PGE 2 in DC activation in hypertension. In vivo, PGE 2 has a predominant effect on EP3 receptors to enhance renal vascular ROS production, which likely leads to isoketal-adduct formation and accumulation in DCs. PGE 2 also acts directly on DCs via its EP1 receptors to stimulate intracellular isoketal formation. Together, these findings provide additional information as to how PGE 2 modulates inflammation in hypertension.

scholarly journals IL-10 Receptor Signaling Empowers Regulatory T Cells to Control Th17 Responses and Protect from GN

2018 ◽  
Vol 29 (7) ◽  
pp. 1825-1837 ◽  
Author(s):  
Paul Diefenhardt ◽  
Anna Nosko ◽  
Malte A. Kluger ◽  
Johannes V. Richter ◽  
Claudia Wegscheid ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Th17 Cells ◽  
Cell Activation ◽  
Molecular Mechanisms ◽  
Receptor Signaling ◽  
Dendritic Cell Activation ◽  
Fluorescent Reporter

Background Th17 cells are central pathogenic mediators of autoimmune disease, including many forms of GN. IL-10 receptor signaling (IL-10R) in regulatory T cells (Tregs) has been implicated in the downregulation of Th17 cells, but the underlying molecular mechanisms and functional relevance of this process remain unclear.Methods We generated mice with Treg-specific IL-10Ra deficiency and subjected these mice to nephrotoxic serum–induced nephritis as a model of crescentic GN. Immune responses and Treg phenotypes were extensively analyzed.Results Compared with controls, mice with IL-10Ra−/− Tregs showed a spontaneously overshooting Th17 immune response. This hyper-Th17 phenotype was further boosted during GN and associated with aggravated renal injury. Notably, abrogation of IL-10Ra signaling in Tregs increased dendritic cell activation and production of Th17-inducing cytokines. In contrast, Treg trafficking and expression of chemokine receptor CCR6 remained unaffected, indicating mechanisms of Th17 control, differing from those of previously identified CCR6+ Treg17 cells. Indeed, the capacity for direct in vitro suppression of Th17 responses by IL-10Ra−/− Tregs was significantly impaired. As underlying pathology, analyses conducted in vitro and in vivo using double-fluorescent reporter mice revealed strikingly decreased IL-10 production by IL-10Ra−/− Tregs. To assess, whether reduced IL-10 could explain the hyper Th17 phenotype, competitive cotransfer experiments were performed. Supporting our concept, IL-10Ra−/− T cells differentiated into Th17 cells at much higher frequencies than wild type T cells did during GN.Conclusions IL-10R engagement optimizes Treg-mediated suppression of Th17 immunity. We hypothesize a feed-forward loop, in which IL-10Ra signaling reinforces IL-10 secretion by Tregs which potently controls Th17 development via direct and indirect mechanisms. IL-10R thus may be a promising therapeutic target for the treatment of GN.

scholarly journals Serine Lipids of Porphyromonas gingivalis Are Human and Mouse Toll-Like Receptor 2 Ligands

2013 ◽  
Vol 81 (9) ◽  
pp. 3479-3489 ◽  
Author(s):  
Robert B. Clark ◽  
Jorge L. Cervantes ◽  
Mark W. Maciejewski ◽  
Vahid Farrokhi ◽  
Reza Nemati ◽  
...  
Keyword(s):  
Cell Activation ◽  
Inflammatory Responses ◽  
Periodontal Pathogen ◽  
Toll Like Receptor ◽  
Dendritic Cell Activation ◽  
Content Type ◽  
Hek Cells ◽  
Toll Like Receptor 2

ABSTRACTThe total cellular lipids ofPorphyromas gingivalis, a known periodontal pathogen, were previously shown to promote dendritic cell activation and inhibition of osteoblasts through engagement of Toll-like receptor 2 (TLR2). The purpose of the present investigation was to fractionate all lipids ofP. gingivalisand define which lipid classes account for the TLR2 engagement, based on bothin vitrohuman cell assays andin vivostudies in mice. Specific serine-containing lipids ofP. gingivalis, called lipid 654 and lipid 430, were identified in specific high-performance liquid chromatography fractions as the TLR2-activating lipids. The structures of these lipids were defined using tandem mass spectrometry and nuclear magnetic resonance methods.In vitro, both lipid 654 and lipid 430 activated TLR2-expressing HEK cells, and this activation was inhibited by anti-TLR2 antibody. In contrast, TLR4-expressing HEK cells failed to be activated by either lipid 654 or lipid 430. Wild-type (WT) or TLR2-deficient (TLR2−/−) mice were injected with either lipid 654 or lipid 430, and the effects on serum levels of the chemokine CCL2 were measured 4 h later. Administration of either lipid 654 or lipid 430 to WT mice resulted in a significant increase in serum CCL2 levels; in contrast, the administration of lipid 654 or lipid 430 to TLR2−/−mice resulted in no increase in serum CCL2. These results thus identify a new class of TLR2 ligands that are produced byP. gingivalisthat likely play a significant role in mediating inflammatory responses both at periodontal sites and, potentially, in other tissues where these lipids might accumulate.

scholarly journals CXCL8 Associated Dendritic Cell Activation Marker Expression and Recruitment as Indicators of Favorable Outcomes in Colorectal Cancer

2021 ◽  
Vol 12 ◽  
Author(s):  
Enhao Li ◽  
Xiaobao Yang ◽  
Yuzhang Du ◽  
Guanzheng Wang ◽  
David W. Chan ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Dendritic Cell ◽  
Cell Activation ◽  
Suppressor Cells ◽  
The Cancer Genome Atlas ◽  
Dendritic Cell Activation ◽  
Antitumor Effects ◽  
Activation Markers

Accumulating evidence suggests that tumor-infiltrating immune cells (TICs) in the tumor microenvironment (TME) serve as promising therapeutic targets. CXCL8 (IL-8) may also be a potential therapeutic target in cancer. CXCL8 is a potent chemotactic factor for neutrophils, myeloid-derived suppressor cells (MDSCs) and monocytes, which are considered immunosuppressive components in cancer-bearing hosts. Here, we identified the TME-related gene CXCL8 in a high-ImmuneScore population that contributed to better survival in colorectal cancer (CRC) patients from The Cancer Genome Atlas (TCGA) database. An integrated gene profile and functional analysis of TIC proportions revealed that the dendritic cell (DC) activation markers CD80, CD83, and CD86 were positively correlated with CXCL8 expression, suggesting that CXCL8 may be functional as antitumor immune response status in the TME. The gene signature was further validated in independent GSE14333 and GSE38832 cohorts from the Gene Expression Omnibus (GEO). To test the differential contributions of immune and tumor components to progression, three CRC cell lines, CT26, MC38 and HCT116, were used. In vitro results suggested no significant growth or survival changes following treatment with an inhibitor of the CXCL8 receptor (CXCR1/2) such as reparixin or danirixin. In vivo treatment with danirixin (antagonists of CXCR2) promoted tumor progression in animal models established with CT26 cells. CXCR2 antagonism may function via an immune component, with CXCR2 antagonist treatment in mice resulting in reduced activated DCs and correlating with decreased Interferon gamma (IFN-γ) or Granzyme B expressed CD8+ T cells. Furthermore, CXCL8 induced DC migration in transwell migration assays. Taken together, our data suggested that targeting the CXCL8-CXCR2 axis might impede DC activation or recruitment, and this axis could be considered a favorable factor rather than a target for critical antitumor effects on CRC.

scholarly journals MicroRNA-21 Regulates Diametrically Opposed Biological Functions of Regulatory T Cells

2021 ◽  
Vol 12 ◽  
Author(s):  
Jijun Sun ◽  
Ruiling Liu ◽  
Xiaozhen He ◽  
Jiang Bian ◽  
Wenbo Zhao ◽  
...  
Keyword(s):  
T Cells ◽  
Autoimmune Disease ◽  
Regulatory T Cells ◽  
Cell Activation ◽  
Treg Cells ◽  
Mechanistic Study ◽  
Dendritic Cell Activation ◽  
Adenoviral Delivery

Regulatory T cells (Tregs) are considered important for controlling the onset and development of autoimmune disease. Although studies have shown that miR-21 is expressed at higher levels in Treg cells, it remains largely elusive whether miR-21 regulates the immune-suppressive function of Tregs. In the current study, we generated mice lacking miR-21 specifically in their Tregs and investigated the role of miR-21 in regulating Treg function both in vitro and in vivo. Our study revealed that Tregs lacking miR-21 exhibit normal phenotype and unaltered function in suppressing T cell proliferation and dendritic cell activation in vitro. However, compared with miR-21-sufficient Tregs, they produce significant more IL-17 and IL-10 when under pathogenic Th17-priming condition. Adenoviral delivery of miR-21 into Treg cells is able to reduce the expression of both IL-17 and IL-10. Mechanistic study revealed that miR-21 down-regulates IL-10 expression through direct targeting of IL-10, and suppresses reprogramming of Tregs into IL-17-secreting cells through down-regulating Stat3 activity. However, we detected no significant or marginal difference in the development of various autoimmune diseases between wild type mice and mice with Treg-specific deletion of miR-21. In conclusion, our study demonstrated that miR-21 in Tregs regulates diametrically opposed biological Treg functions and is largely dispensable for the development of autoimmune disease.

scholarly journals Sodium activates human monocytes via the NADPH oxidase and isolevuglandin formation

2020 ◽  
Author(s):  
Natalia Ruggeri Barbaro ◽  
Justin Van Beusecum ◽  
Liang Xiao ◽  
Luciana do Carmo ◽  
Ashley Pitzer ◽  
...  
Keyword(s):  
Risk Factors ◽  
T Cells ◽  
Nadph Oxidase ◽  
Immune Cells ◽  
Adduct Formation ◽  
High Salt ◽  
Human Monocytes ◽  
Activation Markers

Abstract Aims Prior studies have focused on the role of the kidney and vasculature in salt-induced modulation of blood pressure; however, recent data indicate that sodium accumulates in tissues and can activate immune cells. We sought to examine mechanisms by which salt causes activation of human monocytes both in vivo and in vitro. Methods and results To study the effect of salt in human monocytes, monocytes were isolated from volunteers to perform several in vitro experiments. Exposure of human monocytes to elevated Na+ex vivo caused a co-ordinated response involving isolevuglandin (IsoLG)-adduct formation, acquisition of a dendritic cell (DC)-like morphology, expression of activation markers CD83 and CD16, and increased production of pro-inflammatory cytokines tumour necrosis factor-α, interleukin (IL)-6, and IL-1β. High salt also caused a marked change in monocyte gene expression as detected by RNA sequencing and enhanced monocyte migration to the chemokine CC motif chemokine ligand 5. NADPH-oxidase inhibition attenuated monocyte activation and IsoLG-adduct formation. The increase in IsoLG-adducts correlated with risk factors including body mass index, pulse pressure. Monocytes exposed to high salt stimulated IL-17A production from autologous CD4+ and CD8+ T cells. In addition, to evaluate the effect of salt in vivo, monocytes and T cells isolated from humans were adoptively transferred to immunodeficient NSG mice. Salt feeding of humanized mice caused monocyte-dependent activation of human T cells reflected by proliferation and accumulation of T cells in the bone marrow. Moreover, we performed a cross-sectional study in 70 prehypertensive subjects. Blood was collected for flow cytometric analysis and 23Na magnetic resonance imaging was performed for tissue sodium measurements. Monocytes from humans with high skin Na+ exhibited increased IsoLG-adduct accumulation and CD83 expression. Conclusion Human monocytes exhibit co-ordinated increases in parameters of activation, conversion to a DC-like phenotype and ability to activate T cells upon both in vitro and in vivo sodium exposure. The ability of monocytes to be activated by sodium is related to in vivo cardiovascular disease risk factors. We therefore propose that in addition to the kidney and vasculature, immune cells like monocytes convey salt-induced cardiovascular risk in humans.

Magnoliae Flos Essential Oil as an Immunosuppressant in Dendritic Cell Activation and Contact Hypersensitivity Responses

2020 ◽  
Vol 48 (03) ◽  
pp. 597-613 ◽  
Author(s):  
Chun-Hsien Chen ◽  
Hsin-Chun Chen ◽  
Wen-Te Chang ◽  
Meng-Shiou Lee ◽  
Yi-Chen Liu ◽  
...  
Keyword(s):  
Essential Oil ◽  
Cell Activation ◽  
Nasal Congestion ◽  
Critical Role ◽  
Adaptive Immune Response ◽  
Contact Hypersensitivity ◽  
Dendritic Cell Activation ◽  
Chinese Texts

Magnoliae Flos is a commonly used traditional medicinal material in Asia. It is used to treat sinusitis, nasal congestion, and hypersensitive skin. Because Magonlia Flos was described as an aromatic material in ancient Chinese texts, we hypothesized that its essential oil may be used to treat immune disorders. Dendritic cells (DCs), regarded as a major target of immunomodulators to control immune responses, play a critical role in the adaptive immune response. In this study, Magnoliae Flos essential oil (MFEO) decreased the production of the cytokines TNF-[Formula: see text], IL-6, and IL-12p70 in lipopolysaccharide (LPS)-stimulated DCs. It also suppressed the surface markers MHC II, CD80, and CD86 in LPS-stimulated DCs. Animal models demonstrated that the 2,4-Dinitro-1-fluorobenzene (DNFB) inducing a contact hypersensitivity response was inhibited following treatment with MFEO. In addition, MFEO inhibited the infiltration of T cells in the ears of DNFB-induced mice. To explore its bioactive compounds, the components of MFEO were analyzed using gas chromatography (GC) and GC-mass spectrometry. The results revealed that the major compounds in MFEO are camphor and 1,8-cineole. Additional DC bioassays confirmed that these compounds substantially suppressed cytokine production in LPS-induced DCs. Therefore, we demonstrated that MFEO exhibits an immunosuppressive effect both in vivo and in vitro, and camphor and 1,8-cineole may be the major components responsible for its immunosuppressive ability. The findings indicate that MFEO has the potential to be developed as a new immunosuppressant for excessive diseases.

Naturally arising CD4+CD25+ regulatory T cells suppress the expansion of colitogenic CD4+CD44highCD62L− effector memory T cells

2006 ◽  
Vol 290 (5) ◽  
pp. G1051-G1058 ◽  
Author(s):  
T. Kanai ◽  
K. Tanimoto ◽  
Y. Nemoto ◽  
R. Fujii ◽  
S. Makita ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Effector Memory ◽  
Late Time ◽  
Suppressive Activity ◽  
Time Point

Naturally arising CD4+CD25+ regulatory T (TR) cells have been shown to prevent and cure murine T cell-mediated colitis. However, their exact mechanism of controlling colitogenic memory CD4+ T cells in in vivo systems excluding the initial process of naive T cell activation and differentiation has not been examined to date. Using the colitogenic effector memory (TEM) CD4+ cell-mediated colitis model induced by adoptive transfer of colitogenic CD4+CD44highCD62L− lamina propria (LP) T cells obtained from colitic CD4+CD45RBhigh T cell-transferred mice, we have shown in the present study that CD4+CD25+ TR cells are able not only to suppress the development of colitis, Th1 cytokine production, and the expansion of colitogenic LP CD4+ TEM cells but also to expand these cells by themselves extensively in vivo. An in vitro coculture assay revealed that CD4+CD25+ TR cells proliferated in the presence of IL-2-producing colitogenic LP CD4+ TEM cells at the early time point (48 h after culture), followed by the acquisition of suppressive activity at the late time point (96 h after culture). Collectively, these data suggest the distinct timing of the IL-2-dependent expansion of CD4+CD25+ TR cells and the their suppressive activity on colitogenic LP CD4+ TEM cells.

scholarly journals Inhibition of prostaglandin E2 receptor EP3 mitigates thrombin-induced brain injury

2015 ◽  
Vol 36 (6) ◽  
pp. 1059-1074 ◽  
Author(s):  
Xiaoning Han ◽  
Xi Lan ◽  
Qiang Li ◽  
Yufeng Gao ◽  
Wei Zhu ◽  
...  
Keyword(s):  
Cell Death ◽  
Brain Injury ◽  
Rho Kinase ◽  
Receptor Activation ◽  
Prostaglandin E ◽  
Arterial Blood ◽  
Receptor Inhibition ◽  
Ep3 Receptor

Prostaglandin E2 EP3 receptor is the only prostaglandin E2 receptor that couples to multiple G-proteins, but its role in thrombin-induced brain injury is unclear. In the present study, we exposed mouse hippocampal slice cultures to thrombin in vitro and injected mice with intrastriatal thrombin in vivo to investigate the role of EP3 receptor in thrombin-induced brain injury and explore its underlying cellular and molecular mechanisms. In vitro, EP3 receptor inhibition reduced thrombin-induced hippocampal CA1 cell death. In vivo, EP3 receptor was expressed in astrocytes and microglia in the perilesional region. EP3 receptor inhibition reduced lesion volume, neurologic deficit, cell death, matrix metalloproteinase-9 activity, neutrophil infiltration, and the number of CD68+ microglia, but increased the number of Ym-1+ M2 microglia. RhoA-Rho kinase levels were increased after thrombin injection and were decreased by EP3 receptor inhibition. In mice that received an intrastriatal injection of autologous arterial blood, inhibition of thrombin activity with hirudin decreased RhoA expression compared with that in vehicle-treated mice. However, EP3 receptor activation reversed this effect of hirudin. These findings show that prostaglandin E2 EP3 receptor contributes to thrombin-induced brain damage via Rho-Rho kinase–mediated cytotoxicity and proinflammatory responses.

scholarly journals Cross-effect of TRPV1 and EP3 receptor on coughs and bronchopulmonary C-neural activities

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246375
Author(s):  
Xiuping Gao ◽  
Jianguo Zhuang ◽  
Lei Zhao ◽  
Wan Wei ◽  
Fadi Xu
Keyword(s):  
Sensory Nerve ◽  
Cell Voltage ◽  
Prostaglandin E ◽  
Cross Effect ◽  
C Fibers ◽  
Induced Currents ◽  
The Individual ◽  
Ep3 Receptor

Prostaglandin E2 (PGE2)-induced coughs in vivo and vagal nerve depolarization in vitro are inhibited by systemic and local administration of prostaglandin EP3 receptor (L-798106) and TRPV1 antagonists (JNJ 17203212). These results indicate a modulating effect of TRPV1 on the EP3 receptor-mediated cough responses to PGE2 likely through the vagal sensory nerve. This study aimed to determine whether 1) inhalation of aerosolized JNJ 17203212 and L-798106 affected cough responses to citric acid (CA, mainly stimulating TRPV1) and PGE2; 2) TRPV1 and EP3 receptor morphologically are co-expressed and electrophysiologically functioned in the individual of vagal pulmonary C-neurons (cell bodies of bronchopulmonary C-fibers in the nodose/jugular ganglia); and 3) there was a cross-effect of TRPV1 and EP3 receptor on these neural excitations. To this end, aerosolized CA or PGE2 was inhaled by unanesthetized guinea pigs pretreated without or with each antagonist given in aerosol form. Immunofluorescence was applied to identify the co-expression of TRPV1 and EP3 receptor in vagal pulmonary C-neurons (retrogradely traced by DiI). Whole-cell voltage patch clamp approach was used to detect capsaicin (CAP)- and PGE2-induced currents in individual vagal pulmonary C-neurons and determine the effects of the TRPV1 and EP3 receptor antagonists on the evoked currents. We found that PGE2-induced cough was attenuated by JNJ 17203212 or L-798106 and CA-evoked cough greatly suppressed only by JNJ 17203212. Approximately 1/4 of vagal pulmonary C-neurons co-expressed EP3 with a cell size < 20 μm. Both CAP- and PGE2-induced currents could be recorded in the individuals of some vagal pulmonary C-neurons. The former was largely inhibited only by JNJ 17203212, while the latter was suppressed by JNJ 17203212 or L-798106. The similarity of the cross-effect of both antagonists on cough and vagal pulmonary C-neural activity suggests that a subgroup of vagal pulmonary C-neurons co-expressing TRPV1 and EP3 receptor is, at least in part, responsible for the cough response to PGE2.

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