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

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.

Download Full-text

Bakuchiol Suppresses Inflammatory Responses Via the Downregulation of the p38 MAPK/ERK Signaling Pathway

International Journal of Molecular Sciences ◽

10.3390/ijms20143574 ◽

2019 ◽

Vol 20 (14) ◽

pp. 3574 ◽

Cited By ~ 4

Author(s):

Hye-Sun Lim ◽

Yu Jin Kim ◽

Bu-Yeo Kim ◽

Soo-Jin Jeong

Keyword(s):

Mrna Expression ◽

P38 Mapk ◽

Inflammatory Responses ◽

Mitogen Activated Protein Kinase ◽

Enzyme Linked Immunosorbent Assay ◽

Mice Model ◽

Tnf Α ◽

Cox 2

The purpose of the present study was to evaluate the effects of bakuchiol on the inflammatory response and to identify the molecular mechanism of the inflammatory effects in a lipopolysaccharide (LPS)-stimulated BV-2 mouse microglial cell line and mice model. The production of prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) was measured by enzyme-linked immunosorbent assay. The mRNA expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), TNF-α, and IL-6 was measured using reverse transcription–polymerase chain reaction analysis. Mitogen-activated protein kinase (MAPK) phosphorylation was determined by western blot analysis. In vitro experiments, bakuchiol significantly suppressed the production of PGE2 and IL-6 in LPS-stimulated BV-2 cells, without causing cytotoxicity. In parallel, bakuchiol significantly inhibited the LPS-stimulated expression of iNOS, COX-2, and IL-6 in BV-2 cells. However, bakuchiol had no effect on the LPS-stimulated production and mRNA expression of TNF-α or on LPS-stimulated c-Jun NH2-terminal kinase phosphorylation. In contrast, p38 MAPK and extracellular signal-regulated kinase (ERK) phosphorylation were inhibited by bakuchiol. In vivo experiments, Bakuchiol reduced microglial activation in the hippocampus and cortex tissue of LPS-injected mice. Bakuchiol significantly suppressed LPS-injected production of TNF-α and IL-6 in serum. These results indicate that the anti-neuroinflammatory effects of bakuchiol in activated microglia are mainly regulated by the inhibition of the p38 MAPK and ERK pathways. We suggest that bakuchiol may be beneficial for various neuroinflammatory diseases.

Download Full-text

Potent Inhibitory Effects of Quercetin on Inflammatory Responses of Collagen-Induced Arthritis in Mice

Endocrine Metabolic & Immune Disorders - Drug Targets ◽

10.2174/1871530319666190206225034 ◽

2019 ◽

Vol 19 (3) ◽

pp. 308-315 ◽

Cited By ~ 1

Author(s):

Kiichiro Kawaguchi ◽

Masahiro Kaneko ◽

Ryo Miyake ◽

Hiroaki Takimoto ◽

Yoshio Kumazawa

Keyword(s):

Oral Administration ◽

Inflammatory Responses ◽

Inflammatory Cells ◽

Knee Joints ◽

Therapeutic Effects ◽

Dependent Manner ◽

Inhibitory Effects ◽

Collagen Induced Arthritis ◽

Tnf Α ◽

Flavonoid Quercetin

Background: Production of tumor necrosis factor (TNF)-α by inflammatory cells in lesions is the hallmark of the pathogenesis of rheumatoid arthritis (RA). Regulation of inflammatory responses in knee joints of patients with RA is critical for improving severe symptoms. Flavonoids have inhibitory effects on the acute and chronic inflammatory responses caused by TNF-α. The flavonoid quercetin (QUER) is one of the most prominent dietary antioxidants. Objective: The present study investigated the preventive and therapeutic effects of QUER on inflammatory responses in collagen-induced arthritis (CIA) in mice. Methods: Mice with CIA, a mouse model for RA, were treated with QUER orally three times a week either from the second immunization with collagen (day 21) or day 28 when symptoms of CIA had developed midway. Results: In both cases, inflammation-related clinical scores of knee joints were significantly reduced by treatment with QUER. Histological analyses showed that the representative characteristics of RA, such as damage to interchondral joints, infiltration of inflammatory cells, and pannus formation, were significantly reduced by QUER treatment. Oral administration of QUER significantly decreases lipopolysaccharide (LPS)-induced TNF-α production in a dose-dependent manner. Expression of TNF- α mRNA in knee joints was decreased in QUER-treated mice, compared with those of CIA controls. Conclusion: These results suggest that oral administration of QUER might effectively improve symptoms of RA.

Download Full-text

Chloroquine attenuates lipopolysaccharide-induced inflammatory responses through upregulation of USP25

Canadian Journal of Physiology and Pharmacology ◽

10.1139/cjpp-2016-0303 ◽

2017 ◽

Vol 95 (5) ◽

pp. 481-491 ◽

Cited By ~ 9

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.

Download Full-text

Morin Attenuates Ovalbumin-Induced Airway Inflammation by Modulating Oxidative Stress-Responsive MAPK Signaling

Oxidative Medicine and Cellular Longevity ◽

10.1155/2016/5843672 ◽

2016 ◽

Vol 2016 ◽

pp. 1-13 ◽

Cited By ~ 21

Author(s):

Yuan Ma ◽

Ai Ge ◽

Wen Zhu ◽

Ya-Nan Liu ◽

Ning-Fei Ji ◽

...

Keyword(s):

Oxidative Stress ◽

Airway Inflammation ◽

Inflammatory Responses ◽

Mapk Pathway ◽

Mapk Signaling ◽

Mitogen Activated Protein Kinase ◽

Intercellular Adhesion Molecule ◽

Enzyme Linked Immunosorbent Assay ◽

Chronic Asthma ◽

Cell Counts

Asthma is one of the most common inflammatory diseases characterized by airway hyperresponsiveness, inflammation, and remodeling. Morin, an active ingredient obtained from Moraceae plants, has been demonstrated to have promising anti-inflammatory activities in a range of disorders. However, its impacts on pulmonary diseases, particularly on asthma, have not been clarified. This study was designed to investigate whether morin alleviates airway inflammation in chronic asthma with an emphasis on oxidative stress modulation.In vivo, ovalbumin- (OVA-) sensitized mice were administered with morin or dexamethasone before challenge. Bronchoalveolar lavage fluid (BALF) and lung tissues were obtained to perform cell counts, histological analysis, and enzyme-linked immunosorbent assay.In vitro, human bronchial epithelial cells (BECs) were challenged by tumor necrosis factor alpha (TNF-α). The supernatant was collected for the detection of the proinflammatory proteins, and the cells were collected for reactive oxygen species (ROS)/mitogen-activated protein kinase (MAPK) evaluations. Severe inflammatory responses and remodeling were observed in the airways of the OVA-sensitized mice. Treatment with morin dramatically attenuated the extensive trafficking of inflammatory cells into the BALF and inhibited their infiltration around the respiratory tracts and vessels. Morin administration also significantly suppressed goblet cell hyperplasia and collagen deposition/fibrosis and dose-dependently inhibited the OVA-induced increases in IgE, TNF-α, interleukin- (IL-) 4, IL-13, matrix metalloproteinase-9, and malondialdehyde. In human BECs challenged by TNF-α, the levels of proteins such as eotaxin-1, monocyte chemoattractant protein-1, IL-8 and intercellular adhesion molecule-1, were consistently significantly decreased by morin. Western blotting and the 2′,7′-dichlorofluorescein assay revealed that the increases in intracellular ROS and MAPK phosphorylation were abolished by morin, implying that ROS/MAPK signaling contributes to the relief of airway inflammation. Our findings indicate for the first time that morin alleviates airway inflammation in chronic asthma, which probably occurs via the oxidative stress-responsive MAPK pathway, highlighting a novel profile of morin as a potent agent for asthma management.

Download Full-text

Comparison of therapeutic effects of different mesenchymal stem cells on rheumatoid arthritis in mice

PeerJ ◽

10.7717/peerj.7023 ◽

2019 ◽

Vol 7 ◽

pp. e7023 ◽

Cited By ~ 6

Author(s):

Qing Zhang ◽

Qihong Li ◽

Jun Zhu ◽

Hao Guo ◽

Qiming Zhai ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

Stem Cells ◽

Mesenchymal Stem Cells ◽

Therapeutic Effect ◽

Joint Destruction ◽

Enzyme Linked Immunosorbent Assay ◽

Control Group ◽

Therapeutic Effects ◽

Micro Ct ◽

Tnf Α

Background Rheumatoid arthritis (RA) is a chronic and nonspecific autoimmune disease, which leads to joint destruction and deformity. To investigate the potential of human mesenchymal stem cells (MSCs) as a new therapeutic strategy for patients with RA, we compared the therapeutic effects of bone marrow derived MSCs (BMSCs), umbilical cord derived MSCs (UCs), and stem cells derived from human exfoliated deciduous teeth (SHED) on collagen-induced arthritis (CIA) in mice. Methods A total of 24 DBA/1 mice were infused with type II collagen to induce RA in the experimental model. MSC-treated mice were infused with UCs, BMSCs, and SHED, respectively. Bone erosion and joint destruction were measured by micro-computed tomographic (micro-CT) analysis and hematoxylin and eosin staining. The levels of tumor necrosis factor α (TNF-α) and interleukin-1β (IL-1β) were measured by immunohistochemistry and Enzyme-Linked Immunosorbent Assay (ELISA). Results Systemic delivery of MSCs significantly improved the severity of the symptoms related to CIA to greater extent compared with the untreated control group. Micro-CT revealed reduced bone erosions in the metatarsophalangeal joints upon treatment with MSCs. Additionally, according to histologic evaluation, reduced synovitis and articular destruction were observed in MSC-treated groups. The levels of TNF-α and IL-1β in the serum and joints decreased with treatment by MSCs. Conclusion Our findings suggest that systemic infusion of UCs, BMSCs, and SHED may significantly alleviate the effects of RA. The therapeutic effect of BMSCs was greater than that of SHED, while the UCs were shown to have the best therapeutic effect on CIA mice. In conclusion, compared with BMSCs and SHED, UCs may be a more suitable source of MSCs for the treatment of patients with RA.

Download Full-text

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 ◽

10.3390/molecules26206189 ◽

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.

Download Full-text

Paclitaxel Inhibits Synoviocyte Migration and Inflammatory Mediator Production in Rheumatoid Arthritis

Frontiers in Pharmacology ◽

10.3389/fphar.2021.714566 ◽

2021 ◽

Vol 12 ◽

Author(s):

Xiaochen Chen ◽

Haofeng Lin ◽

Jinyang Chen ◽

Lisheng Wu ◽

Junqing Zhu ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

Inflammatory Mediator ◽

Mapk Pathway ◽

Bone Destruction ◽

New Drugs ◽

Mitogen Activated Protein Kinase ◽

Dependent Manner ◽

Inflammatory Mediator Production ◽

Tnf Α ◽

Mitogen Activated Protein

Activated fibroblast-like synoviocytes (FLSs) play a crucial role in the pathogenesis and progression of rheumatoid arthritis (RA). It is urgent to develop new drugs that can effectively inhibit the abnormal activation of RA-FLS. In our study, the RA-FLS cell line, MH7A, and mice with collagen-induced arthritis (CIA) were used to evaluate the effect of paclitaxel (PTX). Based on the results, PTX inhibited the migration of RA-FLS in a dose-dependent manner and significantly reduced the spontaneous expression of IL-6, IL-8, and RANKL mRNA and TNF-α-induced transcription of the IL-1β, IL-8, MMP-8, and MMP-9 genes. However, PTX had no significant effect on apoptosis in RA-FLS. Mechanistic studies revealed that PTX significantly inhibited the TNF-α-induced phosphorylation of ERK1/2 and JNK in the mitogen-activated protein kinase (MAPK) pathway and suppressed the TNF-α-induced activation of AKT, p70S6K, 4EBP1, and HIF-1α in the AKT/mTOR pathway. Moreover, PTX alleviated synovitis and bone destruction in CIA mice. In conclusion, PTX inhibits the migration and inflammatory mediator production of RA-FLS by targeting the MAPK and AKT/mTOR signaling pathways, which provides an experimental basis for the potential application in the treatment of RA.

Download Full-text

Nasal Epithelial Cells Activated with Alternaria and House Dust Mite Induce Not Only Th2 but Also Th1 Immune Responses

International Journal of Molecular Sciences ◽

10.3390/ijms21082693 ◽

2020 ◽

Vol 21 (8) ◽

pp. 2693

Author(s):

Seung-Heon Shin ◽

Mi-Kyung Ye ◽

Dong-Won Lee ◽

Mi-Hyun Chae ◽

Ba-Da Han

Keyword(s):

Epithelial Cells ◽

House Dust ◽

Inflammatory Responses ◽

Mapk Pathway ◽

House Dust Mites ◽

Enzyme Linked Immunosorbent Assay ◽

Chemical Mediator ◽

Nasal Epithelial Cells ◽

Tnf Α ◽

Ifn Γ

Chronic rhinosinusitis (CRS) is a heterogeneous disease characterized by mucosal inflammation. Airborne allergens are associated with upper and lower airway inflammatory disease. We investigated the effects of airborne allergen stimulation in the nasal epithelial cells and their effect on the peripheral blood mononuclear cells’ (PBMCs) Th immune polarization. Interleukin (IL)-10, IL-25, IL-33, and thymic stromal lymphopoietin (TSLP) levels were determined using the enzyme-linked immunosorbent assay (ELISA) in nasal polyp tissues. Cultured primary nasal epithelial cells were stimulated with Alternaria alternata, Aspergillus fumigatus, Dermatophagoides pteronyssinus (DP), and Dermatophagoides farina (DF) for 48 hours. IL-6, IL-25, IL-33, and TSLP production were measured by ELISA, and the nuclear factor-κB (NF-κB), activator protein 1 (AP-1), and mitogen-activated protein kinase (MAPK) expression were determined by western blot analyses. PBMCs were cultured with nasal epithelial cell-conditioned media (NECM), and IL-5, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α were measured. Innate lymphoid type2 cells (ILC2) were analyzed with flowcytometry. IL-25, IL-33, and TSLP levels were significantly higher in eosinophilic nasal polyps. Alternaria, DP, and DF enhanced IL-33 and TSLP production from the nasal epithelial cells through the NF-κB, AP-1, and MAPK pathway. NECM induced IL-5, IFN-γ, and TNF-α production from PBMCs, without increasing ILC2 expression. Alternaria and house dust mites enhanced the chemical mediator production from nasal epithelial cells and these allergens may induce not only Th2 inflammatory responses but also Th1 inflammatory responses in the nasal mucosa.

Download Full-text

Geniposide, a component of Gardenia jasminoides Ellis, inhibits NF-ĸB to attenuate LPS-induced injury in intestinal epithelial cells

10.21203/rs.3.rs-17588/v1 ◽

2020 ◽

Author(s):

Yizhe Cui ◽

Xinyue Qiao ◽

Qiuju Wang ◽

Rui Wu

Keyword(s):

Epithelial Cells ◽

Inflammatory Responses ◽

Intestinal Epithelial Cells ◽

Inflammatory Factors ◽

Enzyme Linked Immunosorbent Assay ◽

Intestinal Epithelial ◽

Migration Ability ◽

Gardenia Jasminoides ◽

Tnf Α ◽

Gardenia Jasminoides Ellis

Abstract Background: The nuclear factor-ĸB (NF-ĸB) transcriptional system is a major effector pathway involved in inflammatory responses. Previous studies found that a Gardenia decoction (GD) inhibited the expression of NF-κB in a lipopolysaccharide (LPS)-stimulated mouse intestinal injury model. Herein, we hypothesized that geniposide (GE), a component of Gardenia jasminoides Ellis, also exerts anti-inflammatory effects and inhibits NF-ĸB activity in LPS-induced intestinal epithelial cells (IEC-6). IEC-6 cells were stimulated with LPS, following which the effects of GE on NF-ĸB signaling in the IEC-6 cells were examined by western blotting to detect IĸB phosphorylation/degradation. The expression of NF-κB was determined by immunofluorescence assay (IFA). Enzyme-linked immunosorbent assay (ELISA) was used to detect the inhibitory effect of GE on the release of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) activated by LPS in IEC-6 cells. In addition, the migration ability of IEC-6 cells was observed by the scratch method. Results: These results showed that GE dose-dependently downregulated levels of the proinflammatory cytokines TNF-α, IL-6 and IL-1β that had been upregulated by LPS and suppressed the phosphorylation of IĸB and NF-ĸB induced by LPS. Our findings indicated that GE could reduce LPS-induced NF-ĸB signaling and proinﬂammatory expression in IEC-6 cells and significantly enhance the migration of IEC-6 cells. Moreover, GE inhibited the expression of NF-κB, nuclear transfer, and transcriptional activity in IEC-6 cells. Conclusion: GE could block the synthesis of inflammatory factors of IEC-6 cells by inhibiting activation of the IĸB/NF-κB signaling pathway induced by LPS.

Download Full-text

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

Cellular Physiology and Biochemistry ◽

10.1159/000456094 ◽

2017 ◽

Vol 41 (1) ◽

pp. 274-285 ◽

Cited By ~ 4

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.

Download Full-text