scholarly journals Nogo-B Facilitates LPS-Mediated Immune Responses by Up-Regulation of TLR4-Signaling in Macrophage RAW264.7

2017 ◽  
Vol 41 (1) ◽  
pp. 274-285 ◽  
Author(s):  
Ying Zhu ◽  
Qiang Tong ◽  
Jia Ye ◽  
Yunye Ning ◽  
Ye Xiong ◽  
...  
Keyword(s):  
Immune Responses ◽  
Inflammatory Responses ◽  
Scavenger Receptor ◽  
Flow Cytometric Analysis ◽  
Mitogen Activated Protein Kinase ◽  
Enzyme Linked Immunosorbent Assay ◽  
Dependent Manner ◽  
Macrophage Scavenger Receptor ◽  
Mitogen Activated Protein ◽  
Regulatory Functions

Background/Aims: Nogo-B, a member of the reticulon family of proteins, is mainly located in the endoplasmic reticulum (ER). Here, we investigate the function and mechanism of Nogo-B in the regulation of TLR4-associated immune responses in the macrophage cell line of RAW264.7. Methods: Nogo-B was up- and down-regulated through the use of appropriate adenoviral vectors or siRNA, and the effects of Nogo-B on macrophages under liposaccharide (LPS) stimulation were evaluated via western blotting, immunofluorescence, enzyme-linked immunosorbent assay (ELISA), flow cytometric analysis, and transwell assay. Results: Our data indicates that the protein of Nogo-B was down-regulated in a time- and dose-dependent manner following LPS administration in the macrophage. Nogo-B overexpression increased the production of inflammatory cytokines (MCP-1, TNF-α, IL-1β, and TGF-β), enhanced macrophage migration activities, activated major histocompatibility complex II (MHC II), and elevated the expression of macrophage scavenger receptor 1(MSR1), all of which suggest that Nogo-B is necessary for immune responses and plays an important role in regulating macrophage recruitment. Mechanistically, Nogo-B may enhance TLR4 expression in macrophage surfaces, activate mitogen-activated protein kinase (MAPK) pathways, and initiate inflammatory responses. Conclusion: These findings illustrate the key regulatory functions of Nogo-B in facilitating LPS-mediated immune responses through promoting the phosphorylation of MAP kinase.

Chloroquine attenuates lipopolysaccharide-induced inflammatory responses through upregulation of USP25

2017 ◽  
Vol 95 (5) ◽  
pp. 481-491 ◽  
Author(s):  
Changyu Ding ◽  
Fangfang Li ◽  
Yupeng Long ◽  
Jiang Zheng
Keyword(s):  
Macrophage Activation ◽  
Nuclear Translocation ◽  
Inflammatory Responses ◽  
Ubiquitin Proteasome System ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Activation Of Transcription ◽  
Tnf Α ◽  
Mitogen Activated Protein ◽  
Ubiquitin Proteasome

Lipopolysaccharide (LPS) is a key pathogenic factor in sepsis, and its recognition by toll-like receptor 4 (TLR4) can activate two district signaling pathways, leading to activation of transcription factors including NF-κB and interferon regulatory factor 3 (IRF3). Chloroquine (CQ) has been shown to affect LPS–TLR4 colocalization and inhibit both MyD88-dependent and TRAM/TRIF-dependent pathways, though the mechanism involved is still poorly understood. Here, we found that the ubiquitin–proteasome system might be involved in this process. CQ increased USP25, a deubiquitinating enzyme, as well as mRNA and protein expression in a dose-dependent manner, which might to some degree be involved in CQ attenuation of LPS-induced macrophage activation. Overexpression of USP25 decreased LPS-induced inflammatory cytokines like TNF-α, IL-6, and IFN-β, while specific siRNA-mediated USP25 silencing increased TNF-α, IL-6, and IFN-β production and secretion. In addition, USP25 deletion strengthened mitogen-activated protein kinase (MAPKs) phosphorylation and IκB degradation. Moreover, USP25 interference increased NF-κB and IRF3 nuclear translocation. Taken together, our data demonstrated a new possible regulator of LPS-induced macrophage activation mediated by CQ, through upregulation of USP25.

scholarly journals Standardized Extract of Asparagus officinalis Stem Attenuates SARS-CoV-2 Spike Protein-Induced IL-6 and IL-1β Production by Suppressing p44/42 MAPK and Akt Phosphorylation in Murine Primary Macrophages

Molecules ◽  
2021 ◽  
Vol 26 (20) ◽  
pp. 6189
Author(s):  
Ken Shirato ◽  
Jun Takanari ◽  
Takako Kizaki
Keyword(s):  
Nuclear Translocation ◽  
Inflammatory Responses ◽  
Asparagus Officinalis ◽  
Mitogen Activated Protein Kinase ◽  
Spike Protein ◽  
Enzyme Linked Immunosorbent Assay ◽  
Signaling Proteins ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Tlr4 Signaling

Excessive host inflammation following infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with severity and mortality in coronavirus disease 2019 (COVID-19). We recently reported that the SARS-CoV-2 spike protein S1 subunit (S1) induces pro-inflammatory responses by activating toll-like receptor 4 (TLR4) signaling in macrophages. A standardized extract of Asparagus officinalis stem (EAS) is a unique functional food that elicits anti-photoaging effects by suppressing pro-inflammatory signaling in hydrogen peroxide and ultraviolet B-exposed skin fibroblasts. To elucidate its potential in preventing excessive inflammation in COVID-19, we examined the effects of EAS on pro-inflammatory responses in S1-stimulated macrophages. Murine peritoneal exudate macrophages were co-treated with EAS and S1. Concentrations and mRNA levels of pro-inflammatory cytokines were assessed using enzyme-linked immunosorbent assay and reverse transcription and real-time polymerase chain reaction, respectively. Expression and phosphorylation levels of signaling proteins were analyzed using western blotting and fluorescence immunomicroscopy. EAS significantly attenuated S1-induced secretion of interleukin (IL)-6 in a concentration-dependent manner without reducing cell viability. EAS also markedly suppressed the S1-induced transcription of IL-6 and IL-1β. However, among the TLR4 signaling proteins, EAS did not affect the degradation of inhibitor κBα, nuclear translocation of nuclear factor-κB p65 subunit, and phosphorylation of c-Jun N-terminal kinase p54 subunit after S1 exposure. In contrast, EAS significantly suppressed S1-induced phosphorylation of p44/42 mitogen-activated protein kinase (MAPK) and Akt. Attenuation of S1-induced transcription of IL-6 and IL-1β by the MAPK kinase inhibitor U0126 was greater than that by the Akt inhibitor perifosine, and the effects were potentiated by simultaneous treatment with both inhibitors. These results suggest that EAS attenuates S1-induced IL-6 and IL-1β production by suppressing p44/42 MAPK and Akt signaling in macrophages. Therefore, EAS may be beneficial in regulating excessive inflammation in patients with COVID-19.

scholarly journals FM0807 decelerates experimental arthritis progression by inhibiting inflammatory responses and joint destruction via modulating NF-κB and MAPK pathways

2019 ◽  
Vol 39 (9) ◽  
Author(s):  
Nanwen Zhang ◽  
Zhiwei Liu ◽  
Hongbin Luo ◽  
Weifang Wu ◽  
Kaimei Nie ◽  
...  
Keyword(s):  
Synovial Fluid ◽  
Inflammatory Responses ◽  
Mapk Pathway ◽  
Joint Destruction ◽  
Mitogen Activated Protein Kinase ◽  
Inflammatory Factors ◽  
Enzyme Linked Immunosorbent Assay ◽  
Therapeutic Effects ◽  
Dependent Manner ◽  
Tnf Α

Abstract Background: Rheumatoid arthritis (RA) is a chronic articular synovial inflammatory disease. The precise etiology underlying the pathogenesis of RA remains unknown. We aimed to investigate the inhibitory effect of curcumin analog FM0807 (curcumin salicylate monoester, 2-hydroxy-, 4-[(1E,6E)-7-(4-hydroxy-3-methoxyphenyl)-3,5-dioxo-1,6-heptadien-1-yl]-2-methoxyphenyl ester) on experimental RA and investigate its possible mechanisms of action. Method: Rats with Freund’s complete adjuvant (FCA)-induced arthritis (AIA) were administered aspirin (0.1 mmol.kg−1), curcumin (0.1 mmol.kg−1), FM0807 (0.1, 0.2 mmol.kg−1) and vehicle via gastric gavage, from days 7 to 21, once daily. The hind paw volume and arthritis index (AI) were measured, and radiographic and histological examinations were performed. Twenty-one days later, the animals were killed and left ankle joints were removed to measure protein expression of the elements of the nuclear factor κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathway by Western blot analysis. The enzyme-linked immunosorbent assay (ELISA) was employed to measure synovial fluid levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-1β and IL-10. Results: Compared with AIA group, FM0807 reduced the AI and swelling of the injected hind paw in a dose-dependent manner, and inhibited increases in inflammatory cell infiltration, pannus formation and cartilage destruction. FM0807 also potently attenuated the increase in the expression of inflammatory factors TNF-α, IL-6 and IL-1β in synovial fluid, while IL-10 levels were also elevated. FM0807 significantly suppressed phosphorylation of extracellular-signal-regulated kinase (ERK) 1/2 (ERK1/2), c-Jun-N-terminal kinase (JNK) 1/2 (JNK1/2), p38MAPK, inhibitor of NF-κB kinase (IKK), IκB and NF-κB p65 protein, (all P<0.05), which displayed more potential effects compared with those of the aspirin and curcumin groups. Conclusion: FM0807 exerts its therapeutic effects on RA by inhibiting cartilage degeneration. FM0807 treatment might be an effective therapeutic approach for RA.

scholarly journals CD200 Modulates S. aureus-Induced Innate Immune Responses Through Suppressing p38 Signaling

2019 ◽  
Vol 20 (3) ◽  
pp. 659 ◽  
Author(s):  
Bo Zhu ◽  
Yingying Yu ◽  
Xiaoyi Liu ◽  
Qin Han ◽  
Yanhua Kang ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Staphylococcal Infection ◽  
Mitogen Activated Protein Kinase ◽  
No Production ◽  
Dependent Manner ◽  
Innate Immune Responses ◽  
Mouse Macrophages ◽  
Mitogen Activated Protein ◽  
Negative Effect ◽  
Rapid Activation

Rapid activation of macrophages plays a central role in eliminating invading bacteria as well as in triggering the inflammatory responses, but how the anti-bacterial and the inflammatory responses are coordinated, in terms of macrophages, is not completely understood. In this study, we demonstrated that Staphylococcus aureus (S. aureus) induced the expression of CD200 in murine macrophages in a dose-dependent manner. We found that CD200 significantly suppressed the S. aureus-induced production of nitric oxide and proinflammatory cytokines in mouse macrophages. Concurrently, the bactericidal capability of macrophages was boosted upon the deletion of CD200. Furthermore, our data demonstrated that p38 mitogen-activated protein kinase (MAPK) was selectively down-regulated by CD200 administration, while enhanced upon CD200 silence in response to staphylococcal infection. The negative effect of CD200 siRNA on NO production in macrophages was largely abrogated upon the inhibition of p38 signaling, implying its critical involvement in this regulation. Together, our data demonstrate that CD200 plays a central role in regulating the inflammatory responses and the anti-bacterial activity of macrophages, at least partially, through suppressing p38 activity.

scholarly journals Role of MDA5 in regulating CXCL10 expression induced by TLR3 signaling in human rheumatoid fibroblast-like synoviocytes

2021 ◽  
Author(s):  
Tatsuro Saruga ◽  
Tadaatsu Imaizumi ◽  
Shogo Kawaguchi ◽  
Kazuhiko Seya ◽  
Tomoh Matsumiya ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Neutralizing Antibody ◽  
Poly I:C ◽  
Enzyme Linked Immunosorbent Assay ◽  
Dependent Manner ◽  
Inflammatory Reactions ◽  
Polyinosinic:Polycytidylic Acid ◽  
Tlr3 Signaling ◽  
Fibroblast Like Synoviocytes

AbstractC-X-C motif chemokine 10 (CXCL10) is an inflammatory chemokine and a key molecule in the pathogenesis of rheumatoid arthritis (RA). Melanoma differentiation-associated gene 5 (MDA5) is an RNA helicase that plays a role in innate immune and inflammatory reactions. The details of the regulatory mechanisms of CXCL10 production and the precise role of MDA5 in RA synovitis have not been fully elucidated. The aim of this study was to examine the role of MDA5 in regulating CXCL10 expression in cultured human rheumatoid fibroblast-like synoviocytes (RFLS). RFLS was stimulated with Toll-like receptor 3 (TLR3) ligand polyinosinic:polycytidylic acid (poly I:C), a synthetic double-stranded RNA mimetic. Expression of interferon beta (IFN-β), MDA5, and CXCL10 was measured by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blotting, and enzyme-linked immunosorbent assay. A neutralizing antibody of IFN-β and siRNA-mediated MDA5 knockdown were used to determine the role of these molecules in regulating CXCL10 expression downstream of TLR3 signaling in RFLS. Poly I:C induced IFN-β, MDA5, and CXCL10 expression in a concentration- and time-dependent manner. IFN-β neutralizing antibody suppressed the expression of MDA5 and CXCL10, and knockdown of MDA5 decreased a part of CXCL10 expression (p < 0.001). The TLR3/IFN-β/CXCL10 axis may play a crucial role in the inflammatory responses in RA synovium, and MDA5 may be partially involved in this axis.

Mitochondrial ROS initiate phosphorylation of p38 MAP kinase during hypoxia in cardiomyocytes

2002 ◽  
Vol 282 (6) ◽  
pp. L1324-L1329 ◽  
Author(s):  
Andre Kulisz ◽  
Ningfang Chen ◽  
Navdeep S. Chandel ◽  
Zuohui Shao ◽  
Paul T. Schumacker
Keyword(s):  
Kinase Inhibitor ◽  
Anion Channel ◽  
P38 Map Kinase ◽  
Proximal Region ◽  
Mitogen Activated Protein Kinase ◽  
Ros Generation ◽  
Dependent Manner ◽  
Adaptive Responses ◽  
Mitochondrial Ros ◽  
Mitogen Activated Protein

The p38 mitogen-activated protein kinase (MAPK) is phosphorylated in response to oxidative stress. Mitochondria in cardiomyocytes increase their generation of reactive oxygen species (ROS) during hypoxia (1–5% O2). These ROS participate in signal transduction pathways involved in adaptive responses, including ischemic preconditioning and gene transcription. The present study therefore tested the hypothesis that hypoxia induces p38 MAPK phosphorylation by augmenting mitochondrial ROS generation. In cardiomyocytes, phosphorylation of p38 was observed in a Po 2-dependent manner during hypoxia. This response was inhibited by rotenone, thenoyltrifluoroacetone, and myxothiazol, inhibitors of mitochondrial complexes I, II, and III, respectively. A similar inhibition was observed in the cells pretreated with anion channel inhibitor DIDS, which may block ROS release from mitochondria. During normoxia, increases in mitochondrial ROS elicited by azide (1–2 mM) or by the mitochondrial inhibitor antimycin A caused increased phosphorylation of p38. Brief treatment with exogenous H2O2 during normoxia also induced phosphorylation of p38 as hypoxia, but this effect was not abolished by myxothiazol or DIDS. The antioxidant N-acetyl-cysteine abolished the p38 response to hypoxia, presumably by scavenging H2O2, but the mitogen extracellular receptor kinase inhibitor PD-98059 did not inhibit p38 phosphorylation during hypoxia. Thus physiological hypoxia leads to p38 phosphorylation through a mechanism that requires electron flux in the proximal region of the mitochondrial electron transport chain, which suggests that either H2O2 or superoxide participates in activating that process.

scholarly journals Human Articular Chondrocytes Induce Interleukin-2 Nonresponsiveness to Allogeneic Lymphocytes

Cartilage ◽  
2016 ◽  
Vol 8 (3) ◽  
pp. 300-306 ◽  
Author(s):  
Satomi Abe ◽  
Hitoshi Nochi ◽  
Hiroshi Ito
Keyword(s):  
T Cells ◽  
Articular Chondrocytes ◽  
Interleukin 2 ◽  
Flow Cytometric Analysis ◽  
Third Party ◽  
Soluble Form ◽  
Enzyme Linked Immunosorbent Assay ◽  
Dependent Manner ◽  
Activated T Cells ◽  
Allogeneic Lymphocytes

Introduction We previously showed that articular chondrocytes (ACs) have immune privilege and immunomodulatory functions like those of mesenchymal stem cells. To elucidate these mechanisms, we focused on interleukin-2 (IL-2), which plays critical roles in lymphocyte mitogenic activity. The purpose of this study was to explore whether ACs affect the role of IL-2 underlying immunomodulatory functions. Material and Methods Irradiated human ACs from osteoarthritis donors were used. Third-party ACs were added to the mixed lymphocyte reaction (MLR) with or without recombinant human IL-2 (rhIL-2), and the levels of IL-2 and the soluble form of the IL-2 receptor α (sIL-2Rα) protein in supernatant were measured by enzyme-linked immunosorbent assay. Recombinant human IL-2 (rhIL-2) was also added to the MLR. To detect the expression of IL-2 receptor α (CD25) on lymphocytes in the MLR, flow cytometric analysis was performed. Last, ACs and allogeneic activated CD4+ T cell were co-cultured, and the expression of CD25 on activated T cells was examined by flow cytometry. Results Third-party ACs significantly inhibited the MLR and reduced the level of sIL-2Rα in a dose-dependent manner, but did not affect the concentration of IL-2. Exogenous rhIL-2 accelerated MLR but did not rescue the inhibitory effect of ACs. ACs inhibited the expression of CD25 on activated CD4+ T cells. Discussion Our results showed that third-party ACs inhibited the proliferation of allogeneic activated lymphocytes, thereby inhibiting production sIL-2Rα, although ACs did not affect IL-2 secretion from lymphocytes. Also, ACs inhibited CD25 expression on activated CD4+ T cells. Thus, ACs inhibited the immune response of allogeneic lymphocytes by inducing IL-2 nonresponsiveness.

scholarly journals Platyphyllenone Induces Autophagy and Apoptosis by Modulating the AKT and JNK Mitogen-Activated Protein Kinase Pathways in Oral Cancer Cells

2021 ◽  
Vol 22 (8) ◽  
pp. 4211
Author(s):  
Yen-Tze Liu ◽  
Hsin-Yu Ho ◽  
Chia-Chieh Lin ◽  
Yi-Ching Chuang ◽  
Yu-Sheng Lo ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Oral Cancer ◽  
Protein Expression ◽  
Caspase 3 ◽  
Therapeutic Option ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Cancer Proliferation ◽  
Mitogen Activated Protein

Platyphyllenone is a type of diarylheptanoid that exhibits anti-inflammatory and chemoprotective effects. However, its effect on oral cancer remains unclear. In this study, we investigated whether platyphyllenone can promote apoptosis and autophagy in SCC-9 and SCC-47 cells. We found that it dose-dependently promoted the cleavage of PARP; caspase-3, -8, and -9 protein expression; and also led to cell cycle arrest at the G2/M phase. Platyphyllenone up-regulated LC3-II and p62 protein expression in both SCC-9 and SCC-47 cell lines, implying that it can induce autophagy. Furthermore, the results demonstrated that platyphyllenone significantly decreased p-AKT and increased p-JNK1/2 mitogen-activated protein kinase (MAPK) signaling pathway in a dose-dependent manner. The specific inhibitors of p-JNK1/2 also reduced platyphyllenone-induced cleavage of PARP, caspase-3, and caspase -8, LC3-II and p62 protein expression. These findings are the first to demonstrate that platyphyllenone can induce both autophagy and apoptosis in oral cancers, and it is expected to provide a therapeutic option as a chemopreventive agent against oral cancer proliferation.

Docosahexaenoic Acid, a Peroxisome Proliferator-Activated Receptor-α Activator, Induces Apoptosis in Vascular Smooth Muscle Cells by Activation of P38 Mitogen-Activated Protein Kinase

Hypertension ◽  
2000 ◽  
Vol 36 (suppl_1) ◽  
pp. 679-679
Author(s):  
Quy N Diep ◽  
Rhian M Touyz ◽  
Ernesto L Schiffrin
Keyword(s):  
Smooth Muscle ◽  
Cytochrome C ◽  
Docosahexaenoic Acid ◽  
Vascular Smooth Muscle ◽  
Morphological Changes ◽  
Mitogen Activated Protein Kinase ◽  
Peroxisome Proliferator ◽  
Dependent Manner ◽  
Mitogen Activated Protein ◽  
P38 Mapks

9 Omega-3 fatty acids (n-3 FAs) exert a blood pressure-lowering effect in hypertension, possibly by influencing vascular structure. We previously demonstrated that n-3 FAs might induce vascular smooth muscle cell (VSMC) apoptosis, which could exert an effect on structure of blood vessels. This study investigated signaling pathways through which n-3 FAs mediate apoptosis in VSMCs. Cultured Mesenteric VSMCs from Sprague Dawley rats were stimulated with docosahexaenoic acid (DHA), a representative n-3 FA. Morphological changes of apoptosis and DNA fragmentation were examined by phase-contrast microscopy and fluorescence microscopy with Hoechst 33342 staining. To clarify possible pathways of apoptosis, expression of phosphorylated p38 mitogen-activated protein kinases (p38 MAPKs), bax, bcl-2, cytochrome C and peroxisome proliferator-activated receptors-α (PPARs-α) was evaluated by Western blot analysis. DHA treatment induced cell shrinkage, cell membrane blebbing and apoptotic bodies in VSMCs. DHA increased apoptosis (%) in a time-dependent manner to 1.5±0.1, 3.6±0.5, 7.1±0.4, 22.5±0.6, 50.8±1.8 and 61.4±0.9 after 0, 1, 3, 6, 17, and 24 h, respectively. DHA time-dependently activated p38 MAPKs, bax, PPARs-α and cytochrome C with maximal effects obtained after 5, 30 min, 1 h and 3 h, respectively to 551±42, 245±55, 310±12 and 407±14.7 % of controls, respectively. SB-203580 (10 -5 M) and SB-202190 (10 -5 M), selective p38 inhibitors, reduced DHA-elicited apoptosis and expression of PPARs-α, but had no effect on expression of bax or cytochrome C. The present results indicate that DHA induces apoptosis in VSMCs through at least two distinct mechanisms: (i) a p38-dependent pathway that regulates PPAR-α and (ii) a p38-independent pathway via dissipation of mitochondrial transmembrane potential. The death-signaling pathway mediated by DHA may involve an integration of these multiple pathways. By triggering VSMC apoptosis, DHA could play a pathophysiological role in vascular remodeling in cardiovascular disease.

Sign in / Sign up

Export Citation Format

Share Document