TL;DR: In this paper, a review of NF-κB p65-mediated signaling is presented, followed by a discussion of strategies that directly target NF-Kb p65 in the context of chronic inflammation.
Abstract: The transcription factor NF-κB is a critical regulator of immune and inflammatory responses. In mammals, the NF-κB/Rel family comprises five members: p50, p52, p65 (Rel-A), c-Rel, and Rel-B proteins, which form homo- or heterodimers and remain as an inactive complex with the inhibitory molecules called IκB proteins in resting cells. Two distinct NF-κB signaling pathways have been described: 1) the canonical pathway primarily activated by pathogens and inflammatory mediators, and 2) the noncanonical pathway mostly activated by developmental cues. The most abundant form of NF-κB activated by pathologic stimuli via the canonical pathway is the p65:p50 heterodimer. Disproportionate increase in activated p65 and subsequent transactivation of effector molecules is integral to the pathogenesis of many chronic diseases such as the rheumatoid arthritis, inflammatory bowel disease, multiple sclerosis, and even neurodegenerative pathologies. Hence, the NF-κB p65 signaling pathway has been a pivotal point for intense drug discovery and development. This review begins with an overview of p65-mediated signaling followed by discussion of strategies that directly target NF-κB p65 in the context of chronic inflammation.
TL;DR: An overview is presented on the underlying mechanisms of the effects of SCFAs on both immune and endothelial cells, including HDACs, FFA2 and FFA3 receptors and GPR109A regulation of nuclear factor‐kappa B activation and mitogen‐activated protein kinase (MAPK) signaling pathways.
TL;DR: The mTOR-dependent autophagic flux impairment in a murine model of colitis, human intestinal epithelial cells and active UC patients is probably regulated by TLR4-MyD88-MAPK signalling and the NF-κB pathway.
TL;DR: It is suggested that miR-27a alleviates LPS-induced ALI in mice via reducing inflammation and apoptosis through blocking TLR4/MyD88/NF-κB activation.
Abstract: Acute lung injury (ALI) is a critical clinical condition with a high mortality rate, characterized with excessive uncontrolled inflammation and apoptosis. Recently, microRNAs (miRNAs) have been found to play crucial roles in the amelioration of various inflammation-induced diseases, including ALI. However, it remains unknown the biological function and regulatory mechanisms of miRNAs in the regulation of inflammation and apoptosis in ALI. The aim of this study is to identify and evaluate the potential role of miRNAs in ALI and reveal the underlying molecular mechanisms of their effects. Here, we analyzed microRNA expression profiles in lung tissues from LPS-challenged mice using miRNA microarray. Because microRNA-27a (miR-27a) was one of the miRNAs being most significantly downregulated, which has an important role in regulation of inflammation, we investigated its function. Overexpression of miR-27a by agomir-27a improved lung injury, as evidenced by the reduced histopathological changes, lung wet/dry (W/D) ratio, lung microvascular permeability and apoptosis in the lung tissues, as well as ameliorative survival of ALI mice. This was accompanied by the alleviating of inflammation, such as the reduced total BALF cell and neutrophil counts, decreased levels of tumor necrosis factor alpha (TNF-α), interleukin-1 (IL-6) interleukin-1β (IL-1β) and myeloperoxidase (MPO) activity in BAL fluid. Toll-like receptor 4 (TLR4), an important regulator of the nuclear factor kappa-B (NF-κB) signaling pathway, was identified as a novel target of miR-27a in RAW264.7 cells. Furthermore, our results showed that LPS stimulation increased the expression of MyD88 and NF-κB p65 (p-p65), but inhibited the expression of inhibitor of nuclear factor-κB-α (IκB-α), suggesting the activation of NF-κB signaling pathway. Further investigations revealed that agomir-miR-27a reversed the promoting effect of LPS on NF-κB signaling pathway. The results here suggested that miR-27a alleviates LPS-induced ALI in mice via reducing inflammation and apoptosis through blocking TLR4/MyD88/NF-κB activation.
TL;DR: It is demonstrated that inhibiting the canonical NF‐&kgr;B pathway dampened the therapeutic effect of ionizing radiation (IR), whereas non‐canonical NF-B deficiency promoted IR‐induced anti‐tumor immunity.
TL;DR: Although NF-κB has been identified to be a major contributor to cancer initiation and development, there is evidence revealing its role in tumor suppression, as well as a few important pharmacological strategies that have been developed to modulate NF-σB function.
Abstract: Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is responsible for the regulation of a large number of genes that are involved in important physiological processes, including survival, inflammation, and immune responses. At the same time, this transcription factor can control the expression of a plethora of genes that promote tumor cell proliferation, survival, metastasis, inflammation, invasion, and angiogenesis. The aberrant activation of this transcription factor has been observed in several types of cancer and is known to contribute to aggressive tumor growth and resistance to therapeutic treatment. Although NF-κB has been identified to be a major contributor to cancer initiation and development, there is evidence revealing its role in tumor suppression. This review briefly highlights the major mechanisms of NF-κB activation, the role of NF-κB in tumor promotion and suppression, as well as a few important pharmacological strategies that have been developed to modulate NF-κB function.
TL;DR: The present review focuses on the crosstalk between TLR signaling and Nrf2 pathway with respect to their role in modulation of inflammation in normal as well as pathologic conditions.
TL;DR: This study shows that UTI exerts both anti-inflammatory and anti-oxidative effects by targeting the JNK/NF-κB and PI3K/Akt/Nrf2 pathways.
Abstract: Ulinastatin (UTI) is a broad-spectrum serine protease inhibitor isolated and purified from human urine with strong anti-inflammatory and cytoprotective actions, which is widely used for the treatment of various diseases, such as pancreatitis and sepsis. Although the therapeutic effects of UTI are reported to be associated with a variety of mechanisms, the signaling pathways mediating the anti-inflammatory action of UTI remain to be elucidated. In the present study we carried out a systematic study on the anti-inflammatory and anti-oxidative mechanisms of UTI and their relationships in LPS-treated RAW264.7 cells. Pretreatment with UTI (1000 and 5000 U/mL) dose-dependently decreased the mRNA levels of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, iNOS) and upregulated anti-inflammatory cytokines (IL-10 and TGF-β1) in LPS-treated RAW264.7 cells. UTI pretreatment significantly inhibited the nuclear translocation of NF-κB by preventing the degradation of IκB-α. UTI pretreatment only markedly inhibited the phosphorylation of JNK at Thr183, but it did not affect the phosphorylation of JNK at Tyr185, ERK-1/2 and p38 MAPK; JNK was found to function upstream of the IκB-α/NF-κB signaling pathway. Furthermore, UTI pretreatment significantly suppressed LPS-induced ROS production by activating PI3K/Akt pathways and the nuclear translocation of Nrf2 via promotion of p62-associated Keap1 degradation. However, JNK was not involved in mediating the anti-oxidative stress effects of UTI. In summary, this study shows that UTI exerts both anti-inflammatory and anti-oxidative effects by targeting the JNK/NF-κB and PI3K/Akt/Nrf2 pathways.
TL;DR: It is demonstrated for the first time that the anti-aging protein Klotho may be a potential therapeutic agent to treat DCM by inhibiting oxidative stress and inflammation and the critical roles of the Nrf2 and NF-κB pathways in diabetes-stimulated cardiac injuries are demonstrated.
TL;DR: The data suggest that miR-124 can inhibit neuroinflammation in the development of PD by regulating the MEKK3/NF-κB signalling pathways and implicate mi R-124 as a potential therapeutic target for regulating the inflammatory response in PD.
Abstract: Parkinson’s disease (PD) is the most prevalent neurodegenerative disorder that is characterised by selective loss of midbrain dopaminergic (DA) neurons. Chronic inflammation of the central nervous system is mediated by microglial cells and plays a critical role in the pathological progression of PD. Brain-specific microRNA-124 (miR-124) expression is significantly downregulated in lipopolysaccharide (LPS)-treated BV2 cells and in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of PD. However, whether abnormal miR-124 expression could regulate the activation of microglia remains poorly understood. BV2 cells were activated by exposure to LPS, and the expression levels of miR-124, mitogen-activated protein kinase kinase kinase 3 (MEKK3), and the nuclear factor of kappaB (NF-κB) p-p65 were analysed. Over-expression and knockdown studies of miR-124 were performed to observe the effects on MEKK3/NF-κB signalling pathways, and the induction of pro-inflammatory and neurotoxic factors was assessed. In addition, a luciferase reporter assay was conducted to confirm whether MEKK3 is a direct target of miR-124. Meanwhile, production of miR-124, MEKK3, and p-p65; midbrain DA neuronal death; or activation of microglia were analysed when treated with or without miR-124 in the MPTP-induced model of PD. We found that the knockdown of MEKK3 could inhibit the activation of microglia by regulating NF-κB expression. Over-expression of miR-124 could effectively attenuate the LPS-induced expression of pro-inflammatory cytokines and promote the secretion of neuroprotective factors. We also first identified a unique role of miR-124 in mediating the microglial inflammatory response by targeting MEKK3/NF-κB signalling pathways. In the microglial culture supernatant (MCS) transfer model, over-expression of the miR-124 or knockdown of MEKK3 in BV2 cells prevented SH-SY5Y from apoptosis and death. Moreover, MEKK3 and p-p65 were abundantly expressed in the midbrain. Furthermore, their expression levels increased and microglial activation was observed in the MPTP-induced model of PD. In addition, exogenous delivery of miR-124 could suppress MEKK3 and p-p65 expression and attenuate the activation of microglia in the substantia nigra pars compacta of MPTP-treated mice. miR-124 also could prevent MPTP-dependent apoptotic midbrain DA cell death in a MPTP-induced PD model. Taken together, our data suggest that miR-124 can inhibit neuroinflammation in the development of PD by regulating the MEKK3/NF-κB signalling pathways and implicate miR-124 as a potential therapeutic target for regulating the inflammatory response in PD.
TL;DR: It is found that MERS-CoV 4b was required to prevent a robust NF-κB dependent response during infection, and a model where 4b outcompetes NF-α4 for KPNA4 binding and translocation into the nucleus as a mechanism of interference with the NF-σκB-mediated innate immune response is proposed.
Abstract: Middle East respiratory syndrome coronavirus (MERS-CoV) is a novel human coronavirus that emerged in 2012, causing severe pneumonia and acute respiratory distress syndrome (ARDS), with a case fatality rate of ~36%. When expressed in isolation, CoV accessory proteins have been shown to interfere with innate antiviral signaling pathways. However, there is limited information on the specific contribution of MERS-CoV accessory protein 4b to the repression of the innate antiviral response in the context of infection. We found that MERS-CoV 4b was required to prevent a robust NF-κB dependent response during infection. In wild-type virus infected cells, 4b localized to the nucleus, while NF-κB was retained in the cytoplasm. In contrast, in the absence of 4b or in the presence of cytoplasmic 4b mutants lacking a nuclear localization signal (NLS), NF-κB was translocated to the nucleus leading to the expression of pro-inflammatory cytokines. This indicates that NF-κB repression required the nuclear import of 4b mediated by a specific NLS. Interestingly, we also found that both in isolation and during infection, 4b interacted with α-karyopherin proteins in an NLS-dependent manner. In particular, 4b had a strong preference for binding karyopherin-α4 (KPNA4), which is known to translocate the NF-κB protein complex into the nucleus. Binding of 4b to KPNA4 during infection inhibited its interaction with NF-κB-p65 subunit. Thereby we propose a model where 4b outcompetes NF-κB for KPNA4 binding and translocation into the nucleus as a mechanism of interference with the NF-κB-mediated innate immune response.
TL;DR: It is shown that SAMHD1 suppresses the innate immune responses to viral infections and inflammatory stimuli by inhibiting nuclear factor-κB activation and type I interferon (IFN-I) induction.
Abstract: Sterile alpha motif and HD-domain-containing protein 1 (SAMHD1) blocks replication of retroviruses and certain DNA viruses by reducing the intracellular dNTP pool. SAMHD1 has been suggested to down-regulate IFN and inflammatory responses to viral infections, although the functions and mechanisms of SAMHD1 in modulating innate immunity remain unclear. Here, we show that SAMHD1 suppresses the innate immune responses to viral infections and inflammatory stimuli by inhibiting nuclear factor-κB (NF-κB) activation and type I interferon (IFN-I) induction. Compared with control cells, infection of SAMHD1-silenced human monocytic cells or primary macrophages with Sendai virus (SeV) or HIV-1, or treatment with inflammatory stimuli, induces significantly higher levels of NF-κB activation and IFN-I induction. Exogenous SAMHD1 expression in cells or SAMHD1 reconstitution in knockout cells suppresses NF-κB activation and IFN-I induction by SeV infection or inflammatory stimuli. Mechanistically, SAMHD1 inhibits NF-κB activation by interacting with NF-κB1/2 and reducing phosphorylation of the NF-κB inhibitory protein IκBα. SAMHD1 also interacts with the inhibitor-κB kinase e (IKKe) and IFN regulatory factor 7 (IRF7), leading to the suppression of the IFN-I induction pathway by reducing IKKe-mediated IRF7 phosphorylation. Interactions of endogenous SAMHD1 with NF-κB and IFN-I pathway proteins were validated in human monocytic cells and primary macrophages. Comparing splenocytes from SAMHD1 knockout and heterozygous mice, we further confirmed SAMHD1-mediated suppression of NF-κB activation, suggesting an evolutionarily conserved property of SAMHD1. Our findings reveal functions of SAMHD1 in down-regulating innate immune responses to viral infections and inflammatory stimuli, highlighting the importance of SAMHD1 in modulating antiviral immunity.
TL;DR: Results from genetic experiments and chemical activators of endoplasmic reticulum (ER) stress that suggest a link to the cytosolic inhibitor of NF-κB (IκB)α degradation pathway show that the UPR affects this major control point of NF -κB activation through several mechanisms.
Abstract: Stressful conditions occuring during cancer, inflammation or infection activate adaptive responses that are controlled by the unfolded protein response (UPR) and the nuclear factor of kappa light polypeptide gene enhancer in B-cells (NF-κB) signaling pathway. These systems can be triggered by chemical compounds but also by cytokines, toll-like receptor ligands, nucleic acids, lipids, bacteria and viruses. Despite representing unique signaling cascades, new data indicate that the UPR and NF-κB pathways converge within the nucleus through ten major transcription factors (TFs), namely activating transcription factor (ATF)4, ATF3, CCAAT/enhancer-binding protein (CEBP) homologous protein (CHOP), X-box-binding protein (XBP)1, ATF6α and the five NF-κB subunits. The combinatorial occupancy of numerous genomic regions (enhancers and promoters) coordinates the transcriptional activation or repression of hundreds of genes that collectively determine the balance between metabolic and inflammatory phenotypes and the extent of apoptosis and autophagy or repair of cell damage and survival. Here, we also discuss results from genetic experiments and chemical activators of endoplasmic reticulum (ER) stress that suggest a link to the cytosolic inhibitor of NF-κB (IκB)α degradation pathway. These data show that the UPR affects this major control point of NF-κB activation through several mechanisms. Taken together, available evidence indicates that the UPR and NF-κB interact at multiple levels. This crosstalk provides ample opportunities to fine-tune cellular stress responses and could also be exploited therapeutically in the future.
TL;DR: The joint role of ANRIL, miR‐181b and NF‐κB signalling could aid in further treating and diagnosing CAD and the inflammatory factors and vascular‐protective parameters were released to a greater level.
Abstract: This study was designed to investigate whether ANRIL affected the aetiology of coronary artery disease (CAD) by acting on downstream miR-181b and NF-κB signalling. Altogether 327 CAD patients diagnosed by angiography were included, and mice models of CAD were established. Human coronary endothelial cells (HCAECs) and human umbilical vein endothelial cells (HUVECs) were also purchased. In addition, shRNA-ANRIL, shRNA-NC, pcDNA3.1-ANRIL, miR-181b mimic, miR-181b inhibitor and miR-NC were transfected into the cells. The lipopolysaccharides (LPS) and pyrrolidine dithiocarbamate (PDTC) were also added to activate or deactivate NF-κB signalling. Both highly expressed ANRIL and lowly expressed miR-181b were associated with CAD population aged over 60 years old, with smoking history, with hypertension and hyperlipidemia, with CHOL H 4.34 mmol/L, TG ≥ 1.93 mmol/L and Hcy ≥ 16.8 μmol/L (all P < 0.05). Besides, IL-6, IL-8, NF-κB, TNF-α, iNOS, ICAM-1, VCAM-1 and COX-2 expressions observed within AD mice models were all beyond those within NC and sham-operated groups (P < 0.05). Also VEGF and HSP 70 were highly expressed within AD mice models than within NC and sham-operated mice (P < 0.05). Transfection of either pcDNA-ANRIL or miR-181b inhibitor could significantly fortify HCAECs' viability and put on their survival rate. At the meantime, the inflammatory factors and vascular-protective parameters were released to a greater level (P < 0.05). Finally, highly expressed ANRIL also notably bring down miR-181b expression and raise p50/p65 expressions within HCAECs (P < 0.05). The joint role of ANRIL, miR-181b and NF-κB signalling could aid in further treating and diagnosing CAD.
TL;DR: Important molecular contributions of NF-κB to mechanisms of self-tolerance to autoimmune phenotypes described in what is now a substantial catalog of immune defects conferred by mutations in NF-kkB pathways in mouse models are summarized.
Abstract: NF-κB (nuclear factor-kappa B) is a transcription complex crucial for host defense mediated by innate and adaptive immunity, where canonical NF-κB signaling, mediated by nuclear translocation of RelA, c-Rel, and p50, is important for immune cell activation, differentiation, and survival. Non-canonical signaling mediated by nuclear translocation of p52 and RelB contributes to lymphocyte maturation and survival and is also crucial for lymphoid organogenesis. We outline NF-κB signaling and regulation, then summarize important molecular contributions of NF-κB to mechanisms of self-tolerance. We relate these mechanisms to autoimmune phenotypes described in what is now a substantial catalog of immune defects conferred by mutations in NF-κB pathways in mouse models. Finally, we describe Mendelian autoimmune syndromes arising from human NF-κB mutations, and speculate on implications for understanding sporadic autoimmune disease.
TL;DR: A viral mechanism of immune evasion that involves the suppression of NF-κB activation is reviewed to provide new insights into and references for the control and prevention of viral diseases.
Abstract: Nuclear factor-κB (NF-κB) is an important transcription factor that induces the expression of antiviral genes and viral genes. NF-κB activation needs the activation of NF-κB upstream molecules, which include receptors, adaptor proteins, NF-κB (IκB) kinases (IKKs), IκBα, and NF-κB dimer p50/p65. To survive, viruses have evolved the capacity to utilize various strategies that inhibit NF-κB activity, including targeting receptors, adaptor proteins, IKKs, IκBα, and p50/p65. To inhibit NF-κB activation, viruses encode several specific NF-κB inhibitors, including NS3/4, 3C and 3C-like proteases, viral deubiquitinating enzymes (DUBs), phosphodegron-like (PDL) motifs, viral protein phosphatase (PPase)-binding proteins, and small hydrophobic (SH) proteins. Finally, we briefly describe the immune evasion mechanism of human immunodeficiency virus 1 (HIV-1) by inhibiting NF-κB activity in productive and latent infections. This paper reviews a viral mechanism of immune evasion that involves the suppression of NF-κB activation to provide new insights into and references for the control and prevention of viral diseases.
TL;DR: NKILA can serve as a promising agent of enhancing the cytotoxicity of X‐ray radiation on laryngeal cancer and addressing the radioresistance of larynGEal cancer.
Abstract: Laryngeal cancer is one of the most common head and neck malignant tumors and is commonly resistant to X-ray-based radiotherapy. NF-κB interacting lncRNA (NKILA) has been reported to serve as a tumor suppressor in several cancers through combining with NF-κB: IκB complex thereby inhibiting NF-κB activation. Herein, we demonstrated a low NKILA expression in laryngeal cancer and its correlation with shorter overall survival in patients with laryngeal cancer. NKILA serves as a tumor suppressor in laryngeal cancer by suppressing laryngeal cancer cell viability and migration, whereas promoting cell apoptosis; NKILA knockdown reverses the cytotoxicity of X-ray radiation on laryngeal cancer cells through combining with NF-κB: IκB complex to inhibit IκB phosphorylation, inhibit p65 nuclear translocation, and finally inhibit NF-κB activation. NF-κB binds to the promoter region of NKILA to activate its transcriptional activity, upregulated NKILA then inhibits IκB phosphorylation and NF-κB activation, thus forming a negative feedback loop to sensitize laryngeal cancer cell to X-ray radiation. In conclusion, NKILA can serve as a promising agent of enhancing the cytotoxicity of X-ray radiation on laryngeal cancer and addressing the radioresistance of laryngeal cancer.
TL;DR: PI demonstrated effective amelioration of synovial inflammation in the ankle joint of CIA mice while suppressing NF-κB-mediated production of pro-inflammatory effectors in activated macrophages.
Abstract: Background: Rheumatoid arthritis (RA) is a chronic autoimmune disorder, characterized by an increased number of M1-like macrophages in the joints. Polyphyllin I (PPI), one of the main components in the Rhizoma of Paris polyphyllin, displays a selective inhibitory effect on various tumor cells. Here we sought to investigate the anti-rheumatoid arthritis effects and mechanisms of PPI on macrophages in vivo and in vitro.
Materials and Methods: In vitro, primary bone marrow-derived macrophages (BMMs) and peritoneal elucidated macrophages (PEMs) were stimulated by lipopolysaccharide (LPS) and Interferon (IFN)-γ and then treated with PPI. We determined the degree of activation of IKKα/β and p65, two key mediators of the NF-κB-mediated inflammatory pathway, by measuring their phosphorylated forms by Western blot. The p65 nuclear localization was detected by immunofluorescent staining. Further, a NF-κB-linked luciferase reporter plasmid, as well as those expressing key mediators of the Toll-like receptor 4 pathway, such as myeloid differentiation primary response 88 (MYD88), interleukin-1 receptor (IL-1R) associated kinase (IRAK)-1, TNF receptor associated factors (TRAF)-6, Transforming growth factor-b–activated kinase 1 (TAK1) and p65, were used to identify the mechanism by which PPI achieves its inhibitory effects on macrophage-mediated inflammation. Moreover, a NF-κB inhibitor, p65-targeted siRNAs, and a p65 plasmid were further used to validate the anti-inflammatory mechanism of PPI. In vivo, PPI (1 mg/kg) was administered intragastrically one time a day for 7 weeks starting on the 42nd day after the first immunization with collagen in a collagen-induced arthritis (CIA) mouse model. Micro-computed Tomography scanning, histological examination, F4/80 and iNOS double immunofluorescent staining and CD4 immunohistochemical staining were performed to determine the effect of PPI treatment on joint structure and inflammation in this model.
Results: PPI reduced the inflammatory cytokines production of PEMs stimulated by LPS/IFN-γ, inhibited the phosphorylation of IKKα/β and p65, and prevented p65 nuclear localization. The NF-κB luciferase assay showed that the target of PPI was closely related to the NF-κB pathway. Moreover, NF-κB inhibition, siRNA-mediated knockdown of p65, and p65 overexpression eliminated PPI's inhibitory effect. In addition, PPI attenuated the bone erosion and synovitis, as well as M1-like macrophage and T cell infiltration, in the ankle joint of the CIA model.
Conclusion: PPI demonstrated effective amelioration of synovial inflammation in the ankle joint of CIA mice while suppressing NF-κB-mediated production of pro-inflammatory effectors in activated macrophages.
TL;DR: It is demonstrated that Ori exerts protective effects in diabetes‐induced renal injury in vivo and in vitro and may be ascribed to its anti‐inflammatory and modulatory effects on the TLR 4/p38‐MAPK and TLR4/NF‐&kgr;B signaling pathways.
TL;DR: Although it is still in infancy, targeting NF-κB or the NF-σB signaling pathway by miRNAs is becoming a promising strategy of cancer treatment.
Abstract: Nuclear factor kappa B (NF-κB) is a pluripotent and crucial dimer transcription factor that orchestrates various physiological and pathological processes, especially cell proliferation, inflammation, and cancer development and progression. NF-κB expression is transient and tightly regulated in normal cells, but it is activated in cancer cells. Recently, numerous studies have demonstrated microRNAs (miRNAs) play a vital role in the NF-κB signaling pathway and NF-κB-associated immune responses, radioresistance and drug resistance of cancer, some acting as inhibitors and the others as activators. Although it is still in infancy, targeting NF-κB or the NF-κB signaling pathway by miRNAs is becoming a promising strategy of cancer treatment.
TL;DR: PDK4 is indispensable to dictate the fate of TNF/NF‐κB‐mediated hepatocyte apoptosis under pyruvate dehydrogenase kinase 4 ( PDK4)‐deficient conditions.
TL;DR: The strong suppressive effects of ZER on the activation of inflammatory markers in the macrophages via MyD88‐dependent NF‐&kgr;B/MAPK/PI3K‐Akt signaling pathways suggest that ZER can be a preventive and potent therapeutic candidate for the management of various inflammatory‐mediated immune disorders.
TL;DR: The results suggest SIRT1 is a key regulator in RA pathogenesis by suppressing aggressive phenotypes and inflammatory response of FLS by inhibiting synovial hyperplasia and inflammation.
Abstract: Rheumatoid arthritis (RA) is an autoimmune disease of the joints characterized by synovial hyperplasia and chronic inflammation. Fibroblast-like synoviocytes (FLS) play a central role in RA initiation, progression, and perpetuation. Prior studies showed that sirtuin 1 (SIRT1), a deacetylase participating in a broad range of transcriptional and metabolic regulations, may impact cell proliferation and inflammatory responses. However, the role of SIRT1 in RA-FLS was unclear. Here, we explored the effects of SIRT1 on the aggressiveness and inflammatory responses of cultured RA-FLS. SIRT1 expression was significantly lower in synovial tissues and FLS from RA patients than from healthy controls. Overexpression of SIRT1 significantly inhibited RA-FLS proliferation, migration, and invasion. SIRT1 overexpression also significantly increased RA-FLS apoptosis and caspase-3 and -8 activity. Focusing on inflammatory phenotypes, we found SIRT1 significantly reduced RA-FLS secretion of TNF-α, IL-6, IL-8, and IL-1β. Mechanistic studies further revealed SIRT1 suppressed NF-κB pathway by reducing p65 protein expression, phosphorylation, and acetylation in RA-FLS. Our results suggest SIRT1 is a key regulator in RA pathogenesis by suppressing aggressive phenotypes and inflammatory response of FLS. Enhancing SIRT1 expression or function in FLS could be therapeutic beneficial for RA by inhibiting synovial hyperplasia and inflammation.
TL;DR: Glycyrrhizin may be used as an effective therapeutic agent against osteoporosis and bone resorption and reducing oxidative stress by inhibiting the MAPK and NF-κB pathways and activating the AMPK/NRF2 signaling.
Abstract: The treatment for osteoporosis involves inhibiting bone resorption and osteoclastogenesis. Glycyrrhizin (GLY) is a triterpenoid saponin glycoside known to be as the most medically efficacious component of the licorice plant. It has strong anti-inflammatory, antioxidant, and antitumor properties. We investigated the effect of GLY on osteoclastogenesis, bone resorption, and intracellular oxidative stress and its molecular mechanisms. In vitro osteoclastogenesis assays were performed using bone marrow monocytes with and without glycyrrhizin. We also evaluated the effects of glycyrrhizin on the secretion of TNF-α, IL-1β, and IL-6 in LPS-stimulated RAW 264.7 cells using ELISA. The effects of glycyrrhizin on the expression of osteoclast-related genes, such as Nfatc1, c-fos, Trap, and cathepsin K (CK), were investigated by RT-PCR. Intracellular reactive oxygen species (ROS) were detected in receptor activator of nuclear factor kappa-Β ligand (RANKL)-stimulated osteoclasts in the presence and absence of glycyrrhizin. During the inhibition of osteoclastogenesis by glycyrrhizin, phosphorylation of AMPK, Nrf2, NF-κB, and MAPK was analyzed using western blotting. Our results showed that glycyrrhizin significantly inhibited RANKL-induced osteoclastogenesis, downregulated the expression of NFATc1, c-fos, TRAP, CK, DC-STAMP, and OSCAR, and inhibited p65, p38, and JNK. Glycyrrhizin was found to significantly decrease the secretion of inflammatory cytokines (TNF-α, IL-1β, and IL-6). Additionally, glycyrrhizin reduced the formation of ROS in osteoclasts by inducing AMPK phosphorylation and nuclear transfer of NRF2, resulting in an upregulation of antioxidant enzymes, such as HO-1, NQO-1, and GCLC. In summary, we found that glycyrrhizin inhibited RANKL-induced osteoclastogenesis. It was also indicated that glycyrrhizin could reduce oxidative stress by inhibiting the MAPK and NF-κB pathways and activating the AMPK/NRF2 signaling. Therefore, glycyrrhizin may be used as an effective therapeutic agent against osteoporosis and bone resorption.
TL;DR: The results suggest that the anti-inflammatory effect of 4′MR is mainly through suppressing RAGE-mediated MAPK/NF-κB signaling pathway and NLRP3 inflammasome activation and could be a novel therapeutic agent for inflammation-related diseases.
Abstract: Advanced glycation end products (AGEs) could interact with the receptor for AGE (RAGE) as a sterile danger signal to induce inflammation. 4′-methoxyresveratrol (4′MR), a polyphenol derived from Dipterocarpaceae, has not been studied for its anti-inflammation effects. In the present study, we sought to explore the protective role of 4′MR in AGEs-induced inflammatory model using RAW264.7 macrophages. 4′MR significantly inhibited gene expression of pro-inflammatory cytokines and chemokines, such as interleukin 1β (IL-1β), interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-α) and monocyte chemoattractant protein-1 (MCP-1), as well as two typical pro-inflammatory enzymes, inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX2). Besides, 4′MR significantly decreased oxidative stress, demonstrated by levels of ROS production, protein carbonyl and advanced oxidation protein product via down-regulation of NADPH oxidase. Further analysis showed that 4′MR attenuated the RAGE overexpression induced by MGO-BSA. It also blocked the downstream signal of AGE-RAGE, particularly, MAPKs including p38 and JNK, and subsequently reduced NF-κB activation. Additionally, 4′MR significantly abated the activation of NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome including NLRP3 and cleaved caspase-1 and reduced the secretion of mature IL-1β. Taken together, our results suggest that the anti-inflammatory effect of 4′MR is mainly through suppressing RAGE-mediated MAPK/NF-κB signaling pathway and NLRP3 inflammasome activation. 4′MR could be a novel therapeutic agent for inflammation-related diseases.
TL;DR: This dataset reveals dynamic interactions in TNFR1-induced NF-κB signaling and identifies both known as well as novel interactors that may help to further unravel the molecular mechanisms steering TNF-induced inflammatory signaling and pathology.
Abstract: Tumor Necrosis Factor (TNF) has a crucial role in inflammation, cell proliferation and cell death. Dysregulation of TNF receptor 1 (TNFR1)-induced Nuclear Factor-kappa B (NF-κB) signaling leads to chronic inflammation and is associated with several human inflammatory pathologies. Hence, TNF neutralization suppresses inflammation and attenuates inflammatory pathology. However, despite its beneficial effects, anti-TNF therapy suffers from efficacy issues and severe immune side effects. There is thus an urging need to identify novel targets for pharmaceutical intervention in the NF-κB signaling pathway. Here, we present a protein-protein interaction dataset of the TNFR1-induced signaling pathway. For this, we used Virotrap, a novel method for studying protein complexes without disrupting the cellular integrity, on 12 central proteins controlling NF-κB and cell death signaling, both under resting conditions as well as upon TNF stimulation. Our dataset reveals dynamic interactions in TNFR1-induced NF-κB signaling and identifies both known as well as novel interactors that may help to further unravel the molecular mechanisms steering TNF-induced inflammatory signaling and pathology. Machine-accessible metadata file describing the reported data (ISA-Tab format)
TL;DR: T-cell immunoglobulin and mucin-domain containing-3 (Tim-3), mediating immune exhaustion in tumor microenvironment, has become a promising target for tumor therapy, but the exact mechanisms for tumor cell-intrinsic Tim-3 in tumor development and its potential contribution in Tim- 3-targeted therapy strategy have not been elucidated yet.
Abstract: T-cell immunoglobulin and mucin-domain containing-3 (Tim-3), mediating immune exhaustion in tumor microenvironment, has become a promising target for tumor therapy. However, the exact mechanisms for tumor cell-intrinsic Tim-3 in tumor development and its potential contribution in Tim-3-targeted therapy strategy have not been elucidated yet. In this study, we showed that human liver cancer tissues contained high ratio of Tim-3-expressing hepatocytes, and cytokines rich in tumor microenvironment and HBV involved in Tim-3 upregulation in malignant hepatocytes. We demonstrated that hepatocyte-specific Tim-3 overexpression enhances tumor cell growth, whereas Tim-3 inhibition on malignant hepatocytes by anti-Tim-3 antibodies or RNAi suppresses tumor growth both in vitro and in Tim-3 knockout mice. Mechanistically, the hepatocyte-Tim-3 receptor activates NF-κB phosphorylation, which in turn stimulates IL-6 secretion and STAT3 phosphorylation. Our results identify tumor cell-intrinsic functions of Tim-3 in tumorigenesis and suggest that blocking Tim-3 in tumor cells might contribute to the clinical efficacy of anti-Tim-3 antibody treatment in the future tumor therapy.
TL;DR: It is found that the expression of miR-216a could be significantly upregulated in the miiuy croaker after challenge with Vibrio anguillarum and lipopolysaccharide, and overexpression ofmiR- 216a suppresses inflammatory cytokine expression and negatively regulates NF-κB signaling, which inhibit an excessive inflammatory response.
Abstract: Inflammation is the host self-protection mechanism to eliminate pathogen invasion. The excessive inflammatory response can result in uncontrolled inflammation, autoimmune diseases, or pathogen dissemination. Recent studies have widely shown that microRNAs (miRNAs) contribute to the regulation of inflammation in mammals by repressing gene expression at the posttranscriptional level. However, the miRNA-mediated mechanism in the inflammatory response in fish remains hazy. In the present study, the regulatory mechanism of the miR-216a-mediated inflammatory response in teleost fish was addressed. We found that the expression of miR-216a could be significantly upregulated in the miiuy croaker after challenge with Vibrio anguillarum and lipopolysaccharide. Bioinformatics predictions demonstrated a potential binding site of miR-216a in the 3' untranslated region of the p65 gene, and the result was further confirmed by luciferase assay. Moreover, both the mRNA and protein levels of p65 in macrophages were downregulated by miR-216a. Deletion mutant analysis of the miR-216a promoter showed that the Ap1 and Sp1 transcription factor binding sites are indispensable for the transcription of miR-216a. Further study revealed that overexpression of miR-216a suppresses inflammatory cytokine expression and negatively regulates NF-κB signaling, which inhibit an excessive inflammatory response. The collective results indicate that miR-216a plays a role as a negative regulator involved in modulating the bacterium-induced inflammatory response.
TL;DR: Results indicate that α-cyperone exerts neuroprotective effects by inhibiting the production of inflammatory cytokines in BV-2 cells through activating Akt/Nrf2/HO-1 and suppressing the NF-κB pathway.
Abstract: Accumulating evidence has shown that activated microglia cause inflammatory immune response, which could lead to neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease. α-Cyperone, one of the main ingredients of Cyperus rotundus oil, has been reported to possess anti-inflammatory activity in activated macrophages. In this study, we found that α-cyperone markedly decreased the production of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) in LPS-induced BV-2 cells. Moreover, α-cyperone inhibited NF-κB activation and enhanced heme oxygenase-1 (HO-1), nuclear factor-E2-related factor 2 (Nrf2) and Akt expression. Furthermore, we found that α-cyperone could upregulate HO-1 expression and enhance nuclear translocation of Nrf2 via activating the Akt signaling pathway, and inhibition of Akt, Nrf2 or HO-1 attenuated LPS-induced expression of proinflammatory cytokines in BV-2 cells. Moreover, the toxicities of conditioned medium from activated microglia toward dopaminergic neuronal SH-SY5Y cells and hippocampal neuronal HT22 cells were significantly inhibited by pretreatment with α-cyperone. Taken together, our results indicate that α-cyperone exerts neuroprotective effects by inhibiting the production of inflammatory cytokines in BV-2 cells through activating Akt/Nrf2/HO-1 and suppressing the NF-κB pathway.
TL;DR: Evidence is provided that TRIM37 plays an important role in constitutive NF‐κB pathway activation and could serve as a prognostic factor and therapeutic target in NSCLC.