Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) is required for lipopolysaccharide stimulation of tumor necrosis factor alpha (TNF-alpha) translation: glucocorticoids inhibit TNF-alpha translation by blocking JNK/SAPK

Characterization of c-Jun N-terminal kinase (JNK) gene reveals involvement of immune defense against Vibrio splendidus infection in Apostichopus japonicus

The c-Jun N-terminal kinase (JNK) constitutes an evolutionarily conserved family of serine/threonine protein kinases, pivotal in regulating various physiological processes in vertebrates, encompassing apoptosis and antibacterial immunity. Nevertheless, the involvement of JNK in the innate immune response remains largely unexplored in pathogen-induced echinoderms. We isolated and characterized the JNK gene from Apostichopus japonicus (AjJNK) in our investigation. The full-length cDNA sequences of AjJNK spanned 1806 bp, comprising a 1299 bp open reading frame (ORF) encoding 432 amino acids, a 274 bp 5'-untranslated region (UTR), and a 233 bp 3'-UTR. Structural analysis revealed the presence of a classical S_TKc domain (37-335 amino acids) within AjJNK and contains several putative immune-related transcription factor-binding sites, including Elk-1, NF-κB, AP-1, and STAT5. Spatial expression analysis indicated ubiquitous expression of AjJNK across all examined tissues, with the highest expression noted in coelomocytes. The mRNA, protein, and phosphorylation levels of AjJNK were obviously induced in coelomocytes upon V. splendidus challenge and lipopolysaccharide stimulation. Immunofluorescence analysis demonstrated predominant cytoplasmic localization of AjJNK in coelomocytes with subsequent nuclear translocation following the V. splendidus challenge in vivo. Moreover, siRNA-mediated knockdown of AjJNK led to a significant increase in intracellular bacterial load, as well as elevated levels of Ajcaspase 3 and coelomocyte apoptosis post V. splendidus infection. Furthermore, the phosphorylation levels of AjJNK inhibited by its specific inhibitor SP600125 and also significantly suppressed the expression of Ajcaspase 3 and coelomocyte apoptosis during pathogen infection. Collectively, these data underscored the pivotal role of AjJNK in immune defense, specifically in the regulation of coelomocyte apoptosis in V. splendidus-challenged A. japonicus.

Mefunidone ameliorates acute liver failure in mice by inhibiting MKK4-JNK pathway

Acute liver failure (ALF) is a critical condition that can lead to substantial liver dysfunction. It is characterized by complex clinical manifestations and rapid progression, presenting significant challenges in diagnosis and treatment. We investigated the protective effect of mefunidone (MFD), a novel antifibrosis pyridone agent, on ALF in mice, and explored its potential mechanism of action. MFD pretreatment can alleviate lipopolysaccharide (LPS) and d-galactosamine (D-GalN)-induced ALF, reduce hepatocyte apoptosis, and reduce inflammation and oxidative stress. Additionally, MFD alleviated LPS/D-GalN-stimulated reactive oxygen species (ROS) production and cell death in AML12 cells. RNA sequencing enrichment analysis showed that MFD significantly affected the Mitogen-Activated Protein Kinase (MAPK) pathway. In vivo and in vitro experiments showed that MFD inhibited MKK4 and JNK phosphorylation. JNK activation caused by MKK4 and JNK activators could eliminate the therapeutic effect of MFD on AML12. In addition, MFD pretreatment alleviated ConA-induced ALF, reduced inflammation and oxidative stress in mice, and reduced mouse mortality. These results suggest that MFD can potentially protect against ALF, partially by inhibiting the MKK4-JNK pathway, and is a promising new therapeutic drug for ALF.

The role of MIF in periodontitis: A potential pathogenic driver, biomarker, and therapeutic target

OBJECTIVE

Periodontitis is an inflammatory disease that involves an imbalance in the oral microbiota, activation of inflammatory and immune responses, and alveolar bone destruction. Macrophage migration inhibitory factor (MIF) is a versatile cytokine involved in several pathological reactions, including inflammatory processes and bone destruction, both of which are characteristics of periodontitis. While the roles of MIF in cancer and other immune diseases have been extensively characterized, its role in periodontitis remains inconclusive.

RESULTS

In this review, we describe a comprehensive analysis of the potential roles of MIF in periodontitis from the perspective of immune response and bone regulation at the cellular and molecular levels. Moreover, we discuss its potential reliability as a novel diagnostic and therapeutic target for periodontitis.

CONCLUSION

This review can aid dental researchers and clinicians in understanding the current state of MIF-related pathogenesis, diagnosis, and treatment of periodontitis.

Probenecid Inhibits Influenza A(H5N1) and A(H7N9) Viruses In Vitro and in Mice

Avian influenza (AI) viruses cause infection in birds and humans. Several H5N1 and H7N9 variants are highly pathogenic avian influenza (HPAI) viruses. H5N1 is a highly infectious bird virus infecting primarily poultry, but unlike other AIs, H5N1 also infects mammals and transmits to humans with a case fatality rate above 40%. Similarly, H7N9 can infect humans, with a case fatality rate of over 40%. Since 1996, there have been several HPAI outbreaks affecting humans, emphasizing the need for safe and effective antivirals. We show that probenecid potently inhibits H5N1 and H7N9 replication in prophylactically or therapeutically treated A549 cells and normal human broncho-epithelial (NHBE) cells, and H5N1 replication in VeroE6 cells and mice.

Polypeptides Isolated from Lactococcus lactis Alleviates Lipopolysaccharide (LPS)-Induced Inflammation in Ctenopharyngodon idella

The main purpose of the present study was to evaluate the anti-inflammatory activity of Lactococcus lactis BL52 and isolate active substances responsible for anti-inflammatory activity. Head-kidney (HK) macrophages were used for in vitro bioassay-guided isolation, and the structure of the two peptides was identified by mass spectrometry analysis. Lipopolysaccharide (LPS)-induced inflammatory responses in Ctenopharyngodon idella were also examined to evaluate the in vivo anti-inflammatory activity of active substances. Two active peptides were isolated by HPLC from L. lactis BL52, and an in vitro anti-inflammatory assay demonstrated that peptide ALBL1 and ALBL2 dose-dependently inhibited LPS-induced inflammatory cytokines TNF-α, IL-6, and IL-1β and inflammatory factors NO and PGE 2 production in macrophages (p < 0.05). After being treated with 20 mg/Kg peptide ALBL1 and ALBL2, the expression levels of TNF-α, IL-6, IL-1β, NO, and PGE 2 were significantly inhibited (p < 0.05). Results from the in vivo test showed that when the concentration of peptide ALBL1 and ALBL2 reached 30 mg/Kg, the LPS-induced upregulations of TNF-α, IL-6, IL-1β, NO, and PGE 2 were prevented. In addition, peptide ALBL1 and ALBL2 blocked the expression of Toll-like receptor 2 (TLR2) and then suppressed the phosphorylation of nuclear transcription factor-kappa B (NF-κB) p65 and degradation inhibitor of IκBα. Moreover, C. idella treated with peptide ALBL1 and ALBL2 can relieve pathological inflammatory responses caused by LPS. These results suggest that the anti-inflammatory properties of peptide ALBL1 and ALBL2 might be a result from the inhibition of IL-6, IL-1β, and TNF-α expressions through the downregulation of Toll2/NF-κB signaling pathways.

Added to pre-existing inflammation, mRNA-lipid nanoparticles induce inflammation exacerbation (IE)

Current nucleoside-modified RNA lipid nanoparticle (modmRNA-LNP) technology has successfully paved the way for the highest clinical efficacy data from next-generation vaccinations against SARS-CoV-2 during the COVID-19 pandemic. However, such modmRNA-LNP technology has not been characterized in common pre-existing inflammatory or immune-challenged conditions, raising the risk of adverse clinical effects when administering modmRNA-LNPs in such cases. Herein, we induce an acute-inflammation model in mice with lipopolysaccharide (LPS) intratracheally (IT), 1 mg kg-1, or intravenously (IV), 2 mg kg-1, and then IV administer modmRNA-LNP, 0.32 mg kg-1, after 4 h, and screen for inflammatory markers, such as pro-inflammatory cytokines. ModmRNA-LNP at this dose caused no significant elevation of cytokine levels in naive mice. In contrast, shortly after LPS immune stimulation, modmRNA-LNP enhanced inflammatory cytokine responses, Interleukin-6 (IL-6) in serum and Macrophage Inflammatory Protein 2 (MIP-2) in liver significantly. Our report identifies this phenomenon as inflammation exacerbation (IE), which was proven to be specific to the LNP, acting independent of mRNA cargo, and was demonstrated to be time- and dose-dependent. Macrophage depletion as well as TLR3 -/- and TLR4-/- knockout mouse studies revealed macrophages were the immune cells involved or responsible for IE. Finally, we show that pretreatment with anti-inflammatory drugs, such as corticosteroids, can partially alleviate IE response in mice. Our findings characterize the importance of LNP-mediated IE phenomena in gram negative bacterial inflammation, however, the generalizability of modmRNA-LNP in other forms of chronic or acute inflammatory and immune contexts needs to be addressed.

Crosstalk between p38 MAPK and GR Signaling

The p38 MAPK is a signaling pathway important for cells to respond to environmental and intracellular stress. Upon activation, the p38 kinase phosphorylates downstream effectors, which control the inflammatory response and coordinate fundamental cellular processes such as proliferation, apoptosis, and differentiation. Dysregulation of this signaling pathway has been linked to inflammatory diseases and cancer. Secretion of glucocorticoids (GCs) is a classical endocrine response to stress. The glucocorticoid receptor (GR) is the primary effector of GCs and plays an important role in the regulation of cell metabolism and immune response by influencing gene expression in response to hormone-dependent activation. Its ligands, the GCs or steroids, in natural or synthetic variation, are used as standard therapy for anti-inflammatory treatment, severe asthma, autoimmune diseases, and several types of cancer. Several years ago, the GR was identified as one of the downstream targets of p38, and, at the same time, it was shown that glucocorticoids could influence p38 signaling. In this review, we discuss the role of the crosstalk between the p38 and GR in the regulation of gene expression in response to steroids and comprehend the importance and potential of this interplay in future clinical applications.

Differential regulation of lipopolysaccharide-induced IL-1β and TNF-α production in macrophages by palmitate via modulating TLR4 downstream signaling

Diabetic patients are susceptible to infectious diseases. Bacterial invasion activates immune cells such as macrophages through interaction between LPS and TLR4, and induces the expression of inflammatory mediators, including IL-1β and TNF-α, which play key roles in the elimination of infections. Unregulated overproduction or underproduction of these cytokines has been reported as a major factor in the development of septic shock, immune deficiency, and autoimmunity. Recent studies found that metabolic abnormalities of diabetes, such as hyperglycemia and dyslipidemia, played a major role in modulating the immune response. In this study, we studied the effects of palmitic acid (PA) pretreatment on LPS-induced IL-1β and TNF-α production and LPS-TLR4 signaling in macrophages. Compared with control, PA pretreatment significantly increased LPS-induced TNF-α production and secretion in macrophages. In contrast, LPS-induced IL-1β production and secretion was significantly suppressed by PA pretreatment. PA pretreatment did not affect the expression levels of TLR4 or Myd88, or the endocytosis of TLR4 in macrophages. However, PA pretreatment significantly suppressed the phosphorylation level and nuclear translocation of NF-κB, and the phosphorylation level of ERK1/2, whereas increased the phosphorylation levels of p38 and JNK. The activation of IKK which was upstream of NF-κB and ERK1/2 was attenuated, while the activation of TAK1 which was upstream of JNK and p38 was augmented by PA pretreatment. Inhibitors of NF-κB, MEK1/2, and p38 significantly decreased IL-1β expression, while JNK and p38 pathway inhibitors significantly inhibited TNF-α expression. The differential regulation of LPS-induced TNF-α and IL-1β production by PA was associated with cellular metabolism of PA, because inhibiting metabolism of PA with etomoxir or pretreatment with Br-PA which cannot be metabolized reversed these effects. We also showed that PA treatment increased acetylated IKK level which might contribute to the suppressed activation of IKK. The present study showed that LPS-induced production of TNF-α and IL-1β was regulated by different TLR4 downstream pathways in macrophages. PA differentially affected LPS-induced production of TNF-α and IL-1β in macrophages through differentially modulating these pathways. Further experiments will be needed to determine how these phenomena lead to the impaired immune response in patients with diabetes.

Glucocorticoid Resistance: Interference between the Glucocorticoid Receptor and the MAPK Signalling Pathways

Endogenous glucocorticoids (GCs) are steroid hormones that signal in virtually all cell types to modulate tissue homeostasis throughout life. Also, synthetic GC derivatives (pharmacological GCs) constitute the first-line treatment in many chronic inflammatory conditions with unquestionable therapeutic benefits despite the associated adverse effects. GC actions are principally mediated through the GC receptor (GR), a ligand-dependent transcription factor. Despite the ubiquitous expression of GR, imbalances in GC signalling affect tissues differently, and with variable degrees of severity through mechanisms that are not completely deciphered. Congenital or acquired GC hypersensitivity or resistance syndromes can impact responsiveness to endogenous or pharmacological GCs, causing disease or inadequate therapeutic outcomes, respectively. Acquired GC resistance is defined as loss of efficacy or desensitization over time, and arises as a consequence of chronic inflammation, affecting around 30% of GC-treated patients. It represents an important limitation in the management of chronic inflammatory diseases and cancer, and can be due to impairment of multiple mechanisms along the GC signalling pathway. Among them, activation of the mitogen-activated protein kinases (MAPKs) and/or alterations in expression of their regulators, the dual-specific phosphatases (DUSPs), have been identified as common mechanisms of GC resistance. While many of the anti-inflammatory actions of GCs rely on GR-mediated inhibition of MAPKs and/or induction of DUSPs, the GC anti-inflammatory capacity is decreased or lost in conditions of excessive MAPK activation, contributing to disease susceptibility in tissue- and disease- specific manners. Here, we discuss potential strategies to modulate GC responsiveness, with the dual goal of overcoming GC resistance and minimizing the onset and severity of unwanted adverse effects while maintaining therapeutic potential.

Hypertriglyceridemia during hospitalization independently associates with mortality in patients with COVID-19

BACKGROUND

Alteration in blood triglyceride levels have been found in patients with coronavirus disease 2019 (COVID-19). However, the association between hypertriglyceridemia and mortality in COVID-19 patients is unknown.

OBJECTIVE

To investigate the association between alteration in triglyceride level and mortality in hospitalized COVID-19 patients.

METHODS

We conducted a retrospective study of 600 hospitalized patients with COVID-19 diagnosis (ICD10CM:U07.1) and/or SARS-CoV-2 positive testing results between March 1, 2020 and December 21, 2020 at a tertiary academic medical center in Milwaukee, Wisconsin. De-identified data, including demographics, medical history, and blood triglyceride levels were collected and analyzed. Of the 600 patients, 109 patients died. The triglyceride value on admission was considered the baseline and the peak was defined as the highest level reported during the entire period of hospitalization. Hypertriglyceridemia was defined as greater than 150 mg/dl. Logistic regression analyses were performed to evaluate the association between hypertriglyceridemia and mortality.

RESULTS

There was no significant difference in baseline triglyceride levels between non-survivors (n = 109) and survivors (n = 491) [Median 127 vs. 113 mg/dl, p = 0.213]. However, the non-survivors had significantly higher peak triglyceride levels during hospitalization [Median 179 vs. 134 mg/dl, p < 0.001]. Importantly, hypertriglyceridemia independently associated with mortality [odds ratio=2.3 (95% CI: 1.4-3.7, p = 0.001)], after adjusting for age, gender, obesity, history of hypertension and diabetes, high CRP, high leukocyte count and glucocorticoid treatment in a multivariable logistic regression model.

CONCLUSIONS

Hypertriglyceridemia during hospitalization is independently associated with 2.3 times higher mortality in COVID-19 patients. Prospective studies are needed to independently validate this retrospective analysis.

A novel JNK induces innate immune response by activating the expression of antimicrobial peptides in Chinese mitten crab Eriocheir sinensis

c-Jun NH₂-terminal kinase (JNK) is a member of mitogen-activated protein kinases (MAPKs) that participates in the regulation of various physiological and pathological processes. In this study, we identified a novel JNK (EsJNK) and determined the cDNA sequence of its isoform (EsJNK-a) from the Chinese mitten crab Eriocheir sinensis. The open reading frame (ORF) of EsJNK was predicted to encode 421 peptides with a serine/threonine protein kinase, a catalytic (S_TKc) domain, and a low complexity region. The ORF of EsJNK-a was 1380 bp encoding a protein with 459 amino acids, which was 38 amino acids more than that of EsJNK. The predicted tertiary structure of EsJNK was conserved and contained 15 α-helices and 10 β-sheets. Phylogenetic tree analysis revealed that EsJNK was clustered with the JNK homologs of other crustaceans. Quantitative real-time PCR assays showed that EsJNK was expressed in all the tissues examined, but it was relatively higher in hemocytes, muscles, and intestines. The expression of EsJNK mRNA in the hemocytes was upregulated by lipopolysaccharides and peptidoglycans, as well as by Staphylococcus aureus or Vibrio parahaemolyticus challenge. Functionally, after silencing EsJNK by siRNA in crabs, the expression levels of two antimicrobial peptides (AMPs), namely, anti-lipopolysaccharide factor and crustin, were significantly inhibited. The purified recombinant EsJNK protein with His-tag accelerated the elimination of the aforementioned bacteria in vivo. However, knockdown of EsJNK had an opposite effect. These findings suggested that EsJNK might be involved in the antibacterial immune defense of crabs by regulating the transcription of AMPs.

Differential Effects of Toll-Like Receptor Activation and Differential Mediation by MAP Kinases of Immune Responses in Microglial Cells

Microglial activation is believed to play a role in many psychiatric and neurodegenerative diseases. Based largely on evidence from other cell types, it is widely thought that MAP kinase (ERK, JNK and p38) signalling pathways contribute strongly to microglial activation following immune stimuli acting on toll-like receptor (TLR) 3 or TLR4. We report here that exposure of SimA9 mouse microglial cell line to immune mimetics stimulating TLR4 (lipopolysaccharide-LPS) or TLR7/8 (resiquimod/R848), results in marked MAP kinase activation, followed by induction of nitric oxide synthase, and various cytokines/chemokines. However, in contrast to TLR4 or TLR7/8 stimulation, very few effects of TLR3 stimulation by poly-inosine/cytidine (polyI:C) were detected. Induction of chemokines/cytokines at the mRNA level by LPS and resiquimod were, in general, only marginally affected by MAP kinase inhibition, and expression of TNF, Ccl2 and Ccl5 mRNAs, along with nitrite production, were enhanced by p38 inhibition in a stimulus-specific manner. Selective JNK inhibition enhanced Ccl2 and Ccl5 release. Many distinct responses to stimulation of TLR4 and TLR7 were observed, with JNK mediating TNF protein induction by the latter but not the former, and suppressing Ccl5 release by the former but not the latter. These data reveal complex modulation by MAP kinases of microglial responses to immune challenge, including a dampening of some responses. They demonstrate that abnormal levels of JNK or p38 signalling in microglial cells will perturb their profile of cytokine and chemokine release, potentially contributing to abnormal inflammatory patterns in CNS disease states.

Small-Molecule Kinase Inhibitors for the Treatment of Nononcologic Diseases

Great successes have been achieved in developing small-molecule kinase inhibitors as anticancer therapeutic agents. However, kinase deregulation plays essential roles not only in cancer but also in almost all major disease areas. Accumulating evidence has revealed that kinases are promising drug targets for different diseases, including cancer, autoimmune diseases, inflammatory diseases, cardiovascular diseases, central nervous system disorders, viral infections, and malaria. Indeed, the first small-molecule kinase inhibitor for treatment of a nononcologic disease was approved in 2011 by the U.S. FDA. To date, 10 such inhibitors have been approved, and more are in clinical trials for applications other than cancer. This Perspective discusses a number of kinases and their small-molecule inhibitors for the treatment of diseases in nononcologic therapeutic fields. The opportunities and challenges in developing such inhibitors are also highlighted.

Heat-Killed Lactobacillus brevis Enhances Phagocytic Activity and Generates Immune-Stimulatory Effects through Activating the TAK1 Pathway

There is an increasing interest in using inactivated probiotics to modulate the host immune system and protect against pathogens. As the immunomodulatory function of heat-killed Lactobacillus brevis KCTC 12777BP (LBB) and its mechanism is unclear, we investigated the effect of LBB on immune response based on the hypothesis that LBB might exert stimulatory effects on immunity. In the current study, we demonstrate that administration of LBB can exert immune-stimulatory effects and promote clearance of foreign matters through enhancing phagocytosis. Treatment with LBB induced the production of TNF-α, IL-6, and nitric oxide in macrophages. Importantly, LBB directly increased the phagocytic activity of macrophages against bacterial particles. LBB was able to promote the production of TNF-α in bone marrow-derived macrophages and splenocytes and also increase the proliferation rate of splenocytes, suggesting that the immune-stimulating activity of LBB can be observed in primary immune cells. Investigation into the molecular mechanism responsible revealed that LBB upregulates TAK1 activity and its downstream ERK, p38, and JNK signaling pathways. To further confirm the immunomodulatory capability of LBB in vivo, we orally administered LBB to mice and assessed the effect on primary splenocytes. Splenocytes isolated from LBB-treated mice exhibited higher TNF-α expression and proliferative capacity. These results show that heat-killed L. brevis, a wildly consumed probiotic, may provide protection against pathogens through enhancing host immunity.

Elucidating the Pivotal Immunomodulatory and Anti-Inflammatory Potentials of Chloroquine and Hydroxychloroquine

Chloroquine (CQ) and hydroxychloroquine (HCQ) are derivatives of 4-aminoquinoline compounds with over 60 years of safe clinical usage. CQ and HCQ are able to inhibit the production of cytokines such as interleukin- (IL-) 1, IL-2, IL-6, IL-17, and IL-22. Also, CQ and HCQ inhibit the production of interferon- (IFN-) α and IFN-γ and/or tumor necrotizing factor- (TNF-) α. Furthermore, CQ blocks the production of prostaglandins (PGs) in the intact cell by inhibiting substrate accessibility of arachidonic acid necessary for the production of PGs. Moreover, CQ affects the stability between T-helper cell (Th) 1 and Th2 cytokine secretion by augmenting IL-10 production in peripheral blood mononuclear cells (PBMCs). Additionally, CQ is capable of blocking lipopolysaccharide- (LPS-) triggered stimulation of extracellular signal-modulated extracellular signal-regulated kinases 1/2 in human PBMCs. HCQ at clinical levels effectively blocks CpG-triggered class-switched memory B-cells from differentiating into plasmablasts as well as producing IgG. Also, HCQ inhibits cytokine generation from all the B-cell subsets. IgM memory B-cells exhibits the utmost cytokine production. Nevertheless, CQ triggers the production of reactive oxygen species. A rare, but serious, side effect of CQ or HCQ in nondiabetic patients is hypoglycaemia. Thus, in critically ill patients, CQ and HCQ are most likely to deplete all the energy stores of the body leaving the patient very weak and sicker. We advocate that, during clinical usage of CQ and HCQ in critically ill patients, it is very essential to strengthen the CQ or HCQ with glucose infusion. CQ and HCQ are thus potential inhibitors of the COVID-19 cytokine storm.

Effect of corticosteroid (triamcinolone acetonide) and chlorhexidin on chemotherapy- induced oxidative stress in buccal mucosa of rats

Oral mucositis (OM) refers to erythematous and ulcerative lesions of the oral mucosa. This pathology can occur by various causes. Cancer therapy is one of the well-known causes of OM such as chemotherapy and/or with radiation therapy. It has been widely mentioned that oxidative stress parameters such as lipid peroxidation (LP) levels increase during cancer process. Glutathione (GSH) is one of the major intracellular enzymes to detoxify oxidant molecules. The aim of this study was to investigate and compare the effects of Triamcinolone Acetonide (TA), a synthetic steroid chlorhexidine (CHX), a chemical antiseptic, on 5- fluorouracil (5-FU), a chemotherapeutic agent and soft abrasion induced OM in buccal mucosa of rats.OM was induced in rats through a combination of 5-FU treatment and mild abrasion of the cheek pouch with a wire brush. Buccal mucosa lipid peroxidation (LP) levels were higher (p< 0.05) in 5-FU group than in control although LP levels were lower (p<0.05) in TA group than in control group. The reduced glutathione levels were lower (p<0.05) in 5-FU group than in the control group although its level was higher (p<0.05) in TA and CHX groups than in the 5-FU group. Glutathione peroxidase activity was also higher (p<0.05) in TA group than the 5- FU group. In histopathological analyses, treatment with TA reduced 5-FU induced inflammatory cell infiltration and ulceration (p<0.001) but not with CHX.In conclusion, we observed that TA and CHX treatment modulated chemotherapy induced oxidative injury in the rat OM. However, only TA histopathologically ameliorated the 5-FU induced OM of rats. These findings suggest that TA is a useful agent for management of experimental oxidative injury and OM caused by the chemotherapy.

β-Caryophyllene Inhibits Cell Proliferation through a Direct Modulation of CB2 Receptors in Glioblastoma Cells

Glioblastomas are aggressive cancers characterized by uncontrolled proliferation and inflammation. b-caryophyllene (BCP) is a cannabinoid receptor 2 (CB2) agonist that showed an important anti-inflammatory effect through the interaction of CB2 and peroxisome proliferator-activated receptor gamma (PPARg) receptors. BCP effects were investigated in an in vitro model of glioblastoma. U-373 and U87, derived from a human glioblastoma, and human glioma stem-like cells (GSCs) were treated with BCP at different doses and time-points. AM360, a specific CB2 antagonist, was added 2 h before BCP treatment. BCP showed a significant anti-proliferative effect, reducing cell viability, inhibiting cell cycle, and increasing apoptosis, as demonstrated by Tunel assay, caspase-3 and caspase -9 activation. In addition, the pro-apoptotic BAX expression was increased, whereas the anti-apoptotic Bcl-2 expression was reduced. Treatment with BCP decreased Beclin-1, LC3 and p62/SQSTM1 expression, indicating a possible switch of autophagy to apoptosis. BCP’s anti-inflammatory effect was demonstrated by NF-κB reduction, PPARg activation and TNF-a decrease; BCP significantly reduced Jun N-Terminal Kinase (JNK) expression as a consequence of TNF-α inhibition. AM360 abrogated BCP effects, thus demonstrating the BCP mechanism of action through the CB2 receptor. These findings let us hypothesize that BCP may act as a tumor suppressor in glioblastoma, acting on CB2 receptor and modulating JNK.

Fish c-Jun N-Terminal Kinase (JNK) Pathway Is Involved in Bacterial MDP-Induced Intestinal Inflammation

The c-Jun NH₂-terminal kinases (JNKs) are an evolutionarily conserved family of serine/threonine protein kinases that play critical roles in the pathological process in species ranging from insects to mammals. However, the function of JNKs in bacteria-induced intestinal inflammation is still poorly understood. In this study, a fish JNK (CiJNK) pathway was identified, and its potential roles in bacterial muramyl dipeptide (MDP)-induced intestinal inflammation were investigated in Ctenopharyngodon idella. The present CiJNK was found to possess a conserved dual phosphorylation motif (TPY) in a serine/threonine protein kinase (S_TKc) domain and to contain several potential immune-related transcription factor binding sites, including nuclear factor kappa B (NF-κB), activating protein 1 (AP-1), and signal transducer and activator of downstream transcription 3 (STAT3), in its 5′ flanking regions. Quantitative real-time PCR results revealed that the mRNA levels of the JNK pathway genes in the intestine were significantly upregulated after challenge with a bacterial pathogen (Aeromonas hydrophila) and MDP in a time-dependent manner. Additionally, the JNK pathway was found to be involved in regulating the MDP-induced expression levels of inflammatory cytokines (IL-6, IL-8, and TNF-α) in the intestine of grass carp. Moreover, the nutritional dipeptide carnosine and Ala–Gln could effectively alleviate MDP-induced intestinal inflammation by regulating the intestinal expression of JNK pathway genes and inflammatory cytokines in grass carp. Finally, fluorescence microscopy and dual-reporter assays indicated that CiJNK could associate with CiMKK4 and CiMKK7 involved in the regulation of the AP-1 signaling pathway. Overall, these results provide the first experimental demonstration that the JNK signaling pathway is involved in the intestinal immune response to MDP challenge in C. idella, which may provide new insight into the pathogenesis of inflammatory bowel disease.

Caldecrin inhibits lipopolysaccharide-induced pro-inflammatory cytokines and M1 macrophage polarization through the immunoreceptor triggering receptor expressed in myeloid cells-2

Caldecrin was previously isolated as a serum calcium-decreasing factor from the pancreas and is known to suppress receptor activator of nuclear factor-κB ligand (RANKL)-induced calcium oscillation pathways in osteoclasts. Here, we explored the effects of caldecrin on lipopolysaccharide (LPS)-Toll-like receptor-4 (TLR-4) signaling pathways in macrophages. Caldecrin inhibited the LPS-induced gene expression of pro-inflammatory cytokines and M1 macrophage polarization in mouse bone marrow macrophages and the RAW264.7 mouse macrophage cell line. Next, we focused on triggering receptor expressed in myeloid cells-2 (TREM-2) as a co-receptor common to RANKL receptor and TLR-4, and established Trem2-KO RAW264.7 cells, in which Trem2 gene was deleted using the CRISPR/Cas9 system. Caldecrin-mediated alterations in pro-inflammatory cytokine expression and M1 macrophage polarization were not observed in Trem2-KO RAW264.7 cells. These results suggest that caldecrin is not only an inhibitor of osteoclast activation but also a negative regulator of LPS-induced inflammatory responses, functioning via TREM-2.

MAP kinase phosphatase-1, a gatekeeper of the acute innate immune response

Mitogen-activated protein kinase (MAPK)^§ cascades are crucial signaling pathways in the regulation of the host immune response to infection. MAPK phosphatase (MKP)-1, an archetypal member of the MKP family, plays a pivotal role in the down-regulation of p38 and JNK. Studies using cultured macrophages have demonstrated a pivotal role of MKP-1 in the restraint of the biosynthesis of both pro-inflammatory and anti-inflammatory cytokines as well as chemokines. Using MKP-1 knockout mice, several groups have not only confirmed the critical importance of MKP-1 in the regulation of the cytokine synthesis in vivo during the acute host response to bacterial infections, but also revealed novel functions of MKP-1 in maintaining bactericidal functions and host metabolic activities. RNA-seq analyses on livers of septic mice infected with E. coli have revealed that MKP-1 deficiency caused substantial perturbation in the expression of over 5000 genes, an impressive >20% of the entire murine genome. Among the genes whose expression are dramatically affected by MKP-1 deficiency are those encoding metabolic regulators and acute phase response proteins. These studies demonstrate that MKP-1 is an essential gate-keeper of the acute innate immune response, facilitating pathogen killing and regulating the metabolic response during pathogenic infection. In this review article, we will summarize the studies on the function of MKP-1 during acute innate immune response in the regulation of inflammation, metabolism, and acute phase response. We will also discuss the role of MKP-1 in the actions of numerous immunomodulatory agents.

Guavinoside B from Psidium guajava alleviates acetaminophen-induced liver injury via regulating the Nrf2 and JNK signaling pathways

GUB, a main phenolic compound present in guava fruits, could alleviate APAP-induced liver injury in vitro and in vivo by activating the Nrf2 signaling pathway and inhibiting the JNK signaling pathway.

Regulation of Dual-Specificity Phosphatase (DUSP) Ubiquitination and Protein Stability

Mitogen-activated protein kinases (MAPKs) are key regulators of signal transduction and cell responses. Abnormalities in MAPKs are associated with multiple diseases. Dual-specificity phosphatases (DUSPs) dephosphorylate many key signaling molecules, including MAPKs, leading to the regulation of duration, magnitude, or spatiotemporal profiles of MAPK activities. Hence, DUSPs need to be properly controlled. Protein post-translational modifications, such as ubiquitination, phosphorylation, methylation, and acetylation, play important roles in the regulation of protein stability and activity. Ubiquitination is critical for controlling protein degradation, activation, and interaction. For DUSPs, ubiquitination induces degradation of eight DUSPs, namely, DUSP1, DUSP4, DUSP5, DUSP6, DUSP7, DUSP8, DUSP9, and DUSP16. In addition, protein stability of DUSP2 and DUSP10 is enhanced by phosphorylation. Methylation-induced ubiquitination of DUSP14 stimulates its phosphatase activity. In this review, we summarize the knowledge of the regulation of DUSP stability and ubiquitination through post-translational modifications.

Transcription factor Fra-1 targets arginase-1 to enhance macrophage-mediated inflammation in arthritis

The polarization of macrophages is regulated by transcription factors such as nuclear factor kappa B (NF-κB) and activator protein 1 (AP-1). In this manuscript, we delineated the role of the transcription factor Fos-related antigen 1 (Fra-1) during macrophage activation and development of arthritis. Network level interaction analysis of microarray data derived from Fra-1- or Fra-2-deficient macrophages revealed a central role of Fra-1, but not of Fra-2 in orchestrating the expression of genes related to wound response, toll-like receptor activation and interleukin signaling. Chromatin-immunoprecipitation (ChIP)-sequencing and standard ChIP analyses of macrophages identified arginase 1 (Arg1) as a target of Fra-1. Luciferase reporter assays revealed that Fra-1 down-regulated Arg1 expression by direct binding to the promoter region. Using macrophage-specific Fra-1- or Fra-2- deficient mice, we observed an enhanced expression and activity of Arg1 and a reduction of arthritis in the absence of Fra-1, but not of Fra-2. This phenotype was reversed by treatment with the arginase inhibitor Nω-hydroxy-nor-L-arginine, while ʟ-arginine supplementation increased arginase activity and alleviated arthritis, supporting the notion that reduced arthritis in macrophage-specific Fra-1-deficient mice resulted from enhanced Arg1 expression and activity. Moreover, patients with active RA showed increased Fra-1 expression in the peripheral blood and elevated Fra-1 protein in synovial macrophages compared to RA patients in remission. In addition, the Fra-1/ARG1 ratio in synovial macrophages was related to RA disease activity. In conclusion, these data suggest that Fra-1 orchestrates the inflammatory state of macrophages by inhibition of Arg1 expression and thereby impedes the resolution of inflammation.

Discovery of synergistic anti-inflammatory compound combination from herbal formula GuGe FengTong Tablet

Multi-components in herbal formulae exert holistic effects in synergistic or additive manners. However, appropriate strategies and supportive evidences are still lacking to uncover the synergistic or additive combinations. The present investigation aimed at seeking a screening strategy to identify the targeted combinations in GuGe FengTong Tablet (GGFTT), an herbal formula. Two compounds, belonging to different chemical classes, were combined with different concentration ratios and their anti-inflammation effects were investigated. The most significant anti-inflammatory combinations were evaluated by combination index (CI) method (additive effect, CI = 1; synergism, CI < 1; antagonism, CI > 1). The modulating effects of candidate combinations on pro-inflammatory cytokines and MAPKs signaling pathway were also detected. Two combinations, "biochanin A + 6-gingerol" (Bio-6G) and "genistein + 6-gingerol" (Gen-6G), showed synergistic effects (CI < 1), and Bio-6G was selected for further study. Compared with single compound, Bio-6G could synergistically inhibit the production of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) and the activation of MAPKs signaling pathway in LPS-stimulated RAW264.7 cells. The combined results showed that Bio-6G was a synergistic anti-inflammatory combination in GGFTT. Our results could provide a useful strategy to screen the synergistic combinations in herbal formulae.

A novel JNK is involved in immune response by regulating IL expression in oyster Crassostrea gigas

The c-Jun N-terminal kinase (JNK) is a member of mitogen-activated protein kinases (MAPK) highly conserved from yeast to mammals and participates in regulating many physiological and pathological processes. In the present study, a novel JNK was identified from oyster Crassostrea gigas (designated as CgJNK) and its biological functions were investigated in response against lipopolysaccharide (LPS) stimulation. The CgJNK consists of 415 amino acids, which includes a serine/threonine protein kinase (S_TKc) domain with a conserved Thr-Pro-Tyr (TPY) motif. Phylogenetic analysis revealed that CgJNK shared high similarity with other members of the JNK subfamily. CgJNK mRNA was detected in all the tested tissues and CgJNK mRNA expression levels in hemocytes were significantly up-regulated from 6 to 72 h after LPS stimulation and reached the highest level (16.1-fold, p < 0.01) at 24 h. The phosphorylation level of CgJNK in C. gigas hemocytes was increased at 2 h after LPS stimulation. The subcellular localization of CgJNK phosphorylation in hemocytes was analyzed after LPS stimulation, and CgJNK phosphorylation could be detected in both cytoplasm and nucleus of oyster hemocytes at 2 h post LPS stimulation. Additionally, the interleukins (CgILs) were detected in hemocytes of CgJNK-knockdown oysters. CgIL17-1, CgIL17-2, CgIL17-4 and CgIL17-6 transcripts were decreased significantly in CgJNK-knockdown oysters at 24 h post LPS stimulation. In summary, these results suggested that CgJNK played an important role in the immune response of oysters by regulating IL expression.

Kudzu Leaf Extract Suppresses the Production of Inducible Nitric Oxide Synthase, Cyclooxygenase-2, Tumor Necrosis Factor-Alpha, and Interleukin-6 via Inhibition of JNK, TBK1 and STAT1 in Inflammatory Macrophages

Kudzu (Pueraria montana var. lobata (Willd.) Sanjappa & Pradeep) is a perennial leguminous vine, and its root and flower have been used for herbal medicine in Asia for a long time. Most dietary flavonoids are reported to be concentrated in its root, not in its aerial parts including leaves. In this study, we investigated whether kudzu leaf and its major constituent, robinin (kaempferol-3-O-robinoside-7-O-rhanmoside) possessed anti-inflammatory activity. To test this hypothesis, we used peritoneal macrophages isolated from BALB/c mice and stimulated the cells with lipopolysaccharide (LPS) or LPS plus interferon (IFN)-γ. Compared with kudzu root extract, its leaf extract was more potent in inhibiting the production of inducible nitric oxide synthase (iNOS), cyclooxygenase-2, tumor necrosis factor-α, and interleukin-6. Kudzu leaf extract decreased LPS-induced activation of c-Jun N-terminal kinase (JNK) and TANK-binding kinase 1(TBK1) with no effects on nuclear factor-κB and activator protein 1 transcriptional activity. Also, kudzu leaf extract inhibited LPS/IFN-γ-induced signal transducer and activator of transcription 1 (STAT1) activation partly via an altered level of STAT1 expression. Robinin, being present in 0.46% of dry weight of leaf extract, but almost undetected in the root, decreased iNOS protein involving modulation of JNK and STAT1 activation. However, robinin showed no impact on other inflammatory markers. Our data provide evidence that kudzu leaf is an excellent food source of as yet unknown anti-inflammatory constituents.

Identification and analysis of an MKK4 homologue in response to the nucleus grafting operation and antigens in the pearl oyster, Pinctada fucata

The mitogen-activated protein kinase kinase 4 (MKK4) is a key component of the c-Jun N-terminal kinase (JNK) signaling pathway and regulates multiple cellular activities. However, little is known about the roles of this kinase in pearl oyster. In this study, we identified an MKK4 homologue in Pinctada fucata by using a transcriptome database. Sequence analysis and protein structure prediction showed that PfMKK4 is highly conserved to MKK4 from other vertebrate and invertebrate species. Phylogenetic analysis revealed that PfMKK4 has the closest relationship with that from Crassostrea gigas. QPCR was used to investigate expression profiles in different healthy adult tissues and developmental stages of P. fucata. We found that PfMKK4 was ubiquitously expressed in all tissues and developmental stages examined except for in D-shaped larvae. Gene expression analysis suggested that PfMKK4 is involved in the response to the nucleus insertion operation. Lipopolysaccharide (LPS) and polyinosinic:polycytidylic acid [poly(I:C)] stimulation in vivo reduced PfMKK4 mRNA expression at 6 h, 48 h and 48 h, 72 h, respectively. LPS and poly(I:C) induced PfMKK4 phosphorylation in a primary mantle cell culture. These results contribute to better understanding of the potential role played by PfMKK4 in protecting the pearl oyster from injury caused by grafting or disease.

Sambulin A and B, non-glycosidic iridoids from Sambucus ebulus, exert significant in vitro anti-inflammatory activity in LPS-induced RAW 264.7 macrophages via inhibition of MAPKs's phosphorylation

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves of Sambucus ebulus L. (Adoxaceae) are widely used in Turkish folk medicine particularly against inflammatory disorders. The fresh leaves after wilted over fire or the poultices prepared are directly applied externally to heal burns, edema, eczema, urticarial and abscess. Two iridoids were recently isolated (sambulin A, sambulin B) from the leaves of S. ebulus.

AIM OF THE STUDY

This study aims to investigate the in vitro anti-inflammatory activities of these iridoids on LPS-induced RAW 264.7 macrophages.

MATERIALS AND METHODS

Raw 264.7 macrophages were treated with 12.5, 25 and 50µg/ml Sambulin A and 6.25, 12.5 and 25µg/ml Sambulin B and induced with 1µg/ml lipopolysaccaharides (LPS). Effect of the compounds on nitric oxide (NO) production and cytokines (TNFα, IL-6) were determined by Griess and ELISA assays respectively. iNOS and the phosphorylation levels of MAPKs (ERK, JNK) were examined by Western Blot.

RESULTS

Sambulin A and sambulin B inhibited 52.82% and 72.88% of NO production at 50 and 25µg/ml concentrations respectively. The levels of iNOS were significantly decreased by both molecules, sambulin B at 25µg/ml almost completely decreased iNOS levels (97.53%). Both molecules significantly inhibited TNFα productions. However, only sambulin B inhibited IL-6 production. Consequently, it was shown that sambulin B exerted its effect through the inhibition of ERK and JNK phosphorylations.

CONCLUSION

The prominent bioactivities exerted by two iridoids will contribute to explanation of the usage of S. ebulus in traditional medicine against rheumatoid diseases.

Effect of a corticosteroid (triamcinolone) and chlorhexidine on chemotherapy-induced oxidative stress in the buccal mucosa of rats

Oral mucositis manifests as erythematous and ulcerative lesions of the oral mucosa. Among its various causes, cancer treatment (e.g., chemotherapy with or without radiation therapy) is one of the more well known. It has been widely mentioned that oxidative stress parameters such as lipid peroxidation levels increase during the cancer process. Glutathione is one of the major intracellular enzymes used to detoxify oxidant molecules; it exists in both a reduced and oxidized state. Reduced glutathione is used as a substrate to synthesize glutathione peroxidase. We conducted a study to investigate and compare the effects of triamcinolone (a synthetic steroid) and chlorhexidine (a chemical antiseptic) on 5-fluorouracil (5-FU; a chemotherapeutic agent)-induced oral mucositis in the buccal mucosa of 36 rats. Oral mucositis was induced through a combination of 5-FU treatment and mild abrasion of the cheek pouch with a wire brush. The rats were treated with one of four regimens: saline placebo (group I), 5-FU only (group II), 5-FU plus triamcinolone (group III), and 5-FU plus chlorhexidine (group IV). Three rats in the triamcinolone group died of unknown causes on days 7 and 8, and 3 rats in the chlorhexidine group died on days 7 and 9. On day 9, the remaining 30 rats were sacrificed and examined. Buccal mucosa lipid peroxidation levels were significantly higher in the 5-FU-only group than in the control group and significantly higher in the control group than in the triamcinolone group (p < 0.05 for both). Levels of reduced glutathione were significantly lower in the 5-FU-only group than in both the triamcinolone group and the chlorhexidine group (p < 0.05). Glutathione peroxidase activity was significantly higher in the triamcinolone group than in the 5-FU-only group (p < 0.01). Histopathologic analysis revealed that treatment with triamcinolone significantly reduced 5-FU-induced inflammatory cell infiltration and ulceration (p < 0.001); no such reduction was seen with chlorhexidine. In conclusion, we observed that triamcinolone and chlorhexidine treatment modulated chemotherapy-induced oxidative injury in rat oral mucositis. However, only triamcinolone histopathologically ameliorated 5-FU-induced oral mucositis. These findings suggest that triamcinolone is a useful agent for the management of experimental oxidative injury and oral mucositis caused by 5-FU chemotherapy.

Isotrifoliol inhibits pro-inflammatory mediators by suppression of TLR/NF-κB and TLR/MAPK signaling in LPS-induced RAW264.7 cells

Soybeans, produced by Glycine max (L.) Merr., contain high levels of isoflavones, such as genistein and daidzein. However, soy leaves contain more diverse and abundant flavonol glycosides and coumestans, as compared to the soybean. This study investigated the anti-inflammatory effects of the major coumestans present in soy leaf (coumestrol, isotrifoliol, and phaseol) in lipopolysaccharide (LPS)-induced RAW264.7 cells. Coumestans significantly reduced LPS-induced nitric oxide (NO), prostaglandin E2 (PGE2), and reactive oxygen species (ROS) production; isotrifoliol had the most potent anti-inflammatory activity. Isotrifoliol reduced LPS-mediated induction of mRNA expression of inducible nitric-oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin (IL)-1β, IL-6, tumor necrosis factor alpha (TNFα), and chemokines, such as chemokine (C-C motif) ligand (CCL) 2, CCL3, and CCL4. Isotrifoliol prevented NF-κB p65 subunit activation by reducing the phosphorylation and degradation of the inhibitor of NF-κB. And isotrifoliol significantly suppressed phosphorylation of the extracellular signal-regulated protein kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (MAPK). Furthermore, isotrifoliol suppressed LPS-induced Toll-like Receptor (TLR) signaling pathway, including mRNA expression of TNF receptor associated factor 6, transforming growth factor beta-activated kinase 1 (TAK1), TAK1 binding protein 2 (TAB2), and TAB3. These results demonstrate that isotrifoliol exerts an anti-inflammatory effect by suppressing the expression of inflammatory mediators via inhibition of TLR/NF-κB and TLR/MAPK signaling in LPS-induced RAW264.7 macrophages. Therefore, isotrifoliol can be used as an anti-inflammatory agent, and coumestan-rich soy leaf extracts may provide a useful dietary supplement.

c-Jun N-terminal kinase (JNK) is involved in immune defense against bacterial infection in Crassostrea hongkongensis

c-Jun N-terminal kinase (JNK) is a universal and essential subgroup of the mitogen-activated protein kinase (MAPK) superfamily, which is highly conserved from yeast to mammals and functions in a variety of physiological and pathological processes. In this study, we report the first oyster JNK gene homolog (ChJNK) and its biological functions in the Hong Kong oyster Crassostrea hongkongensis. The ChJNK protein consists of 383 amino acids and contains a conserved serine/threonine protein kinase (S_TKc) domain with a typical TPY motif. Phylogenetic analysis revealed that ChJNK shared a close evolutionary relationship with Crassostrea gigas JNK. Quantitative RT-PCR analyses revealed broad expression patterns of ChJNK mRNA in various adult tissues and different embryonic and larval stages of C. hongkongensis. When exposed to Vibrio alginolyticus or Staphylococcus haemolyticus, ChJNK mRNA expression levels were significantly up-regulated in the hemocytes and gills in a time-dependent manner. Additionally, subcellular localization studies that ChJNK is a cytoplasm-localized protein, and that its overexpression could significantly enhance the transcriptional activities of AP-1-Luc in HEK293T cells. In summary, this study provided the first experimental demonstration that oysters possess a functional JNK that participates in host defense against bacterial infection in C. hongkongensis.

Lymphadenectomy promotes tumor growth and cancer cell dissemination in the spontaneous RET mouse model of human uveal melanoma

Resection of infiltrated tumor-draining lymph nodes (TDLNs) is a standard practice for the treatment of several cancers including breast cancer and melanoma. However, many randomized prospective trials have failed to show convincing clinical benefits associated with LN removal and the role of TDLNs in cancer dissemination is poorly understood. Here, we found in a well-characterized spontaneous mouse model of uveal melanoma that the growth of the primary tumor was accompanied by increased lymphangiogenesis and cancer cell colonization in the LNs draining the eyes. But, unexpectedly, early resection of the TDLNs increased the growth of the primary tumor and associated blood vessels as well as promoted cancer cell survival and dissemination. These effects were accompanied by increased tumor cell proliferation and expression of phosphorylated AKT. Topical application of a broad anti-inflammatory agent, Tobradex, or an oral treatment with cyclooxygenase-2 specific inhibitor, Celecoxib, reversed tumor progression observed after complete lymphadenectomy. Our study confirms the importance of tumor homeostasis in cancer progression by showing the enhancing effects of TDLN removal on tumor growth and cancer cell dissemination, and suggests that TDLN resection may only be beneficial if used in combination with anti-inflammatory drugs such as Tobradex and Celecoxib.

Long-Term Reduction of Kappa Opioid Receptor Function by the Biased Ligand, Norbinaltorphimine, Requires c-Jun N-Terminal Kinase Activity and New Protein Synthesis in Peripheral Sensory Neurons

A single administration of the κ opioid receptor (KOR) antagonist, norbinaltorphimine (norBNI), produces long-term reduction in KOR function in heterologous expression systems and brain that is mediated by activation of c-Jun N-terminal kinase (JNK). In this study, we examined the long-term effects of norBNI on adult rat peripheral sensory neurons in vivo and ex vivo. Following a single intraplantar (i.pl.) injection of norBNI into the hind paw, peripheral KOR-mediated antinociception in the ipsilateral, but not the contralateral, hindpaw was abolished for at least 9 days. By contrast, the antinociceptive response to mu and delta opioid receptor agonists was unaltered. The long-term inhibitory effect on antinociception produced by pretreatment with norBNI required occupancy of peripheral KOR and was completely blocked by i.pl. injection of the JNK inhibitor, SP600125. In cultures of peripheral sensory neurons, norBNI activated JNK for at least 30 minutes. Furthermore, norBNI blocked KOR-mediated inhibition of adenylyl cyclase activity measured 24 hours later in a JNK-dependent manner, but did not block activation of extracellular signal-regulated kinase (ERK). The long-term inhibitory effect of norBNI on KOR function in vivo and ex vivo was blocked by inhibitors of mRNA translation, cycloheximide and rapamycin. These data suggest that in peripheral sensory neurons norBNI is a KOR-biased ligand for activation of JNK signaling, resulting in long-term blockade of some (antinociception, inhibition of adenylyl cyclase activity), but not all (ERK), KOR signaling. Importantly, norBNI elicits de novo protein synthesis in sensory neuron terminals that produces selective long-term regulation of KOR.

miR-155 targets Caspase-3 mRNA in activated macrophages

To secure the functionality of activated macrophages in the innate immune response, efficient life span control is required. Recognition of bacterial lipopolysaccharides (LPS) by toll-like receptor 4 (TLR4) induces downstream signaling pathways, which merge to induce the expression of cytokine genes and anti-apoptotic genes. MicroRNAs (miRNAs) have emerged as important inflammatory response modulators, but information about their functional impact on apoptosis is scarce. To identify miRNAs differentially expressed in response to LPS, cDNA libraries from untreated and LPS-activated murine macrophages were analyzed by deep sequencing and regulated miRNA expression was verified by Northern blotting and qPCR. Employing TargetScan(TM) we identified CASPASE-3 (CASP-3) mRNA that encodes a key player in apoptosis as potential target of LPS-induced miR-155. LPS-dependent primary macrophage activation revealed TLR4-mediated enhancement of miR-155 expression and CASP-3 mRNA reduction. Endogenous CASP-3 and cleaved CASP-3 protein declined in LPS-activated macrophages. Accumulation of miR-155 and CASP-3 mRNA in miRNA-induced silencing complexes (miRISC) was demonstrated by ARGONAUTE 2 (AGO2) immunoprecipitation. Importantly, specific antagomir transfection effectively reduced mature miR-155 and resulted in significantly elevated CASP-3 mRNA levels in activated macrophages. In vitro translation assays demonstrated that the target site in the CASP-3 mRNA 3'UTR mediates miR-155-dependent Luciferase reporter mRNA destabilization. Strikingly, Annexin V staining of macrophages transfected with antagomir-155 and stimulated with LPS prior to staurosporine (SSP) treatment implied that LPS-induced miR-155 prevents apoptosis through CASP-3 mRNA down-regulation. In conclusion, we report that miR-155-mediated CASP-3 mRNA destabilization in LPS-activated RAW 264.7 macrophages suppresses apoptosis, as a prerequisite to maintain their crucial function in inflammation.

Oleoylethanolamide exerts anti-inflammatory effects on LPS-induced THP-1 cells by enhancing PPARα signaling and inhibiting the NF-κB and ERK1/2/AP-1/STAT3 pathways

The present study aimed to examine the anti-inflammatory actions of oleoylethanolamide (OEA) in lipopolysaccharide (LPS)-induced THP-1 cells. The cells were stimulated with LPS (1 μg/ml) in the presence or absence of OEA (10, 20 and 40 μM). The pro-inflammatory cytokines were evaluated by qRT-PCR and ELISA. The THP-1 cells were transiently transfected with PPARα small-interfering RNA, and TLR4 activity was determined with a blocking test using anti-TLR4 antibody. Additionally, a special inhibitor was used to analyse the intracellular signaling pathway. OEA exerted a potent anti-inflammatory effect by reducing the production of pro-inflammatory cytokines and TLR4 expression, and by enhancing PPARα expression. The modulatory effects of OEA on LPS-induced inflammation depended on PPARα and TLR4. Importantly, OEA inhibited LPS-induced NF-κB activation, IκBα degradation, expression of AP-1, and the phosphorylation of ERK1/2 and STAT3. In summary, our results demonstrated that OEA exerts anti-inflammatory effects by enhancing PPARα signaling, inhibiting the TLR4-mediated NF-κB signaling pathway, and interfering with the ERK1/2-dependent signaling cascade (TLR4/ERK1/2/AP-1/STAT3), which suggests that OEA may be a therapeutic agent for inflammatory diseases.

Sakuranetin Inhibits Inflammatory Enzyme, Cytokine, and Costimulatory Molecule Expression in Macrophages through Modulation of JNK, p38, and STAT1

Sakuranetin is flavonoid phytoalexin that serves as a plant antibiotic and exists in Prunus and several other plant species. Recently, we identified the anti-inflammatory effect of Prunus yedoensis and found that there were few studies on the potential anti-inflammatory activity of sakuranetin, one of the main constituents of Prunus yedoensis. Here, we isolated peritoneal macrophages from thioglycollate-injected mice and examined whether sakuranetin affected the response of the macrophages in response to lipopolysaccharide (LPS) plus interferon- (IFN-) γ or LPS only. Sakuranetin suppressed the synthesis of iNOS and COX2 in LPS/IFN-γ stimulated cells and the secretion of TNF-α, IL-6, and IL-12 in LPS stimulated cells. The surface expression of the costimulatory molecules, CD86 and CD40, was also decreased. Among the LPS-induced signaling molecules, STAT1, JNK, and p38 phosphorylation was attenuated. These findings are evidence that sakuranetin acts as anti-inflammatory flavonoid and further study is required to evaluate its in vivo efficacy.

TNF-α gene polymorphisms and expression

Tumor necrosis factor alpha (TNF-α) is a proinflammatory cytokine with an important role in the pathogenesis of several diseases. Its encoding gene is located in the short arm of chromosome 6 in the major histocompatibility complex class III region. Most of the TNF-α gene polymorphisms are located in its promoter region and they are thought to affect the susceptibility and/or severity of different human diseases. This review summarizes the data related to the association between TNF-α gene and its receptor polymorphisms, and the development of autoimmune diseases. Among these polymorphisms the -308G/A TNF-α promotor polymorphism has been associated several times with the the development of autoimmune diseases, however some discrepant results have been recorded. The other TNF-α gene polymorphisms had little or no association with autoimmune diseases. Current results about the molecules controlling TNF-α expression are also presented. The discrepancy between different records could be related partly to either the differences in the ethnic origin or number of the studied individuals, or the abundance and activation of other molecules that interact with the TNF-α promotor region or other elements.

Anti-inflammatory and anti-insulin resistance activities of aqueous extract from Anoectochilus burmannicus

This study investigated biological activities including antioxidative stress, anti‐inflammation, and anti‐insulin resistance of Anoectochilus burmannicus aqueous extract (ABE). The results showed abilities of ABE to scavenging DPPH and ABTS free radicals in a dose‐dependent manner. Besides, ABE significantly reduced nitric oxide (NO) production in the lipopolysaccharide (LPS)‐treated RAW 264.7 via inhibition of mRNA and protein expressions of nitric oxide synthase (iNOS). The LPS‐induced mRNA expressions of cyclooxygenase‐2 (COX‐2) and interleukin 1β (IL‐1β) were suppressed by ABE. Moreover, ABE exerted anti‐insulin resistance activity as it significantly improved the glucose uptake in tumor necrosis factor (TNF)‐α treated 3T3‐L1 adipocytes. In addition, ABE at the concentration of up to 200 μg/mL was not toxic to human peripheral blood mononuclear cells (PBMCs) and did not induce mutations. Finally, the results of our study suggest the potential use of A. burmannicus as anti‐inflammatory, anti‐insulin resistance agents, or food supplement for prevention of chronic diseases.

The complex cascade of cellular events governing inflammasome activation and IL-1β processing in response to inhaled particles

The innate immune system is the first line of defense against inhaled particles. Macrophages serve important roles in particle clearance and inflammatory reactions. Following recognition and internalization by phagocytes, particles are taken up in vesicular phagolysosomes. Intracellular phagosomal leakage, redox unbalance and ionic movements induced by toxic particles result in pro-IL-1β expression, inflammasome complex engagement, caspase-1 activation, pro-IL-1β cleavage, biologically-active IL-1β release and finally inflammatory cell death termed pyroptosis. In this review, we summarize the emerging signals and pathways involved in the expression, maturation and secretion of IL-1β during these responses to particles. We also highlight physicochemical characteristics of particles (size, surface and shape) which determine their capacity to induce inflammasome activation and IL-1β processing.

Effects and mechanisms of Shaofu-Zhuyu decoction and its major bioactive component for Cold - Stagnation and Blood - Stasis primary dysmenorrhea rats

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine (TCM) is used under the guidance of the theory of traditional Chinese medical sciences in clinical application. The Chinese herbal formula, Shaofu Zhuyu decoction (SFZYD), is considered as an effective prescription for treating Cold - Stagnation and Blood - Stasis (CSBS) primary dysmenorrhea. The previous studies showed the SFZYD exhibited significant anti-inflammation and analgesic effect. In this present study the metabolomics of CSBS primary dysmenorrhea diseased rats and the cytokine transcription in PHA stimulated-PBMC were investigated to explore the effects and mechanisms.

AIM OF THE STUDY

Explore a valuable insight into the effects and mechanisms of SFZYD on Cold - Stagnation and Blood - Stasis primary dysmenorrhea rats.

MATERIALS AND METHODS

We established CSBS primary dysmenorrhea diseased rats according the clinical symptoms. A targeted tandem mass spectrometry (MS/MS)-based metabolomic platform was used to evaluate the metabolic profiling changes and the intervention effects by SFZYD. The PBMC cell was adopted to explore the mechanisms by analyzing the signaling pathway evaluated by expression of inflammatory cytokines, c-jun and c-fos and corresponding phosphorylation levels.

RESULTS

Estradiol, oxytocin, progesterone, endothelin, β-endorphin and PGF2α were restored back to the normal level after the treatment of SFZYD. Total twenty-five metabolites (10 in plasma and 15 in urine), up-regulated or down-regulated, were identified. These identified biomarkers underpinning the metabolic pathway including pentose and glucuronate interconversions, steroid hormone biosynthesis, and glycerophospholipid metabolism are disturbed in model rats. Among these metabolites, twenty one potential biomarkers were regulated after SFZYD treated. The compound of paeoniflorin, a major bioactive compound in SFZYD, was proved to regulate the MAPK signaling pathway by inhibiting the expression of IL-1β, IL-2, IL-10, IL-12, TNFα, INFγ, c-jun and c-fos in PHA stimulated-PBMC.

CONCLUSION

These findings indicated that SFZYD improved the metabolic profiling and biochemical indicators on CSBS primary dysmenorrhea rats. And the mechanisms were closely related with the regulation of the MAPK pathway by reduction in phosphorylated forms of the three MAPK (ERK1/2, p38 and JNK) and down regulation of c-jun and c-fos by paeoniflorin. The data could be provided the guidance for further research and new drug discovery.

The low molecular weight fraction of human serum albumin upregulates production of 15d-PGJ2 in Peripheral Blood Mononuclear Cells

Activation of the innate immune system involves a series of events designed to counteract the initial insult followed by the clearance of debris and promotion of healing. Aberrant regulation can lead to systemic inflammatory response syndrome, multiple organ failure, and chronic inflammation. A better understanding of the innate immune response may help manage complications while allowing for proper immune progression. In this study, the ability of several classes of anti-inflammatory drugs to affect LPS-induced cytokine and prostaglandin release from peripheral blood mononuclear cells (PBMC) was evaluated. PBMC were cultured in the presence of dexamethasone (DEX), ibuprofen (IBU), and the low molecular weight fraction of 5% albumin (LMWF5A) followed by stimulation with LPS. After 24 h, TNFα, PGE2, and 15d-PGJ2 release was determined by ELISA. Distinct immunomodulation patterns emerged following LPS stimulation of PBMC in the presence of said compounds. DEX, a steroid with strong immunosuppressive properties, reduced TNFα, PGE2, and 15d-PGJ2 release. IBU caused significant reduction in prostaglandin release while TNFα release was unchanged. An emerging biologic with known anti-inflammatory properties, LMWF5A, significantly reduced TNFα release while enhancing PGE2 and 15d-PGJ2 release. Incubating LMWF5A together with IBU negated this observed increased prostaglandin release without affecting the suppression of TNFα release. Additionally, LMWF5A caused an increase in COX-2 transcription and translation. LMWF5A exhibited a unique immune modulation pattern in PBMC, disparate from steroid or NSAID administration. This enhancement of prostaglandin release (specifically 15d-PGJ2), in conjunction with a decrease in TNFα release, suggests a switch that favors resolution and decreased inflammation.

6-Mercaptopurine attenuates tumor necrosis factor-α production in microglia through Nur77-mediated transrepression and PI3K/Akt/mTOR signaling-mediated translational regulation

Background

The pathogenesis of several neurodegenerative diseases often involves the microglial activation and associated inflammatory processes. Activated microglia release pro-inflammatory factors that may be neurotoxic. 6-Mercaptopurine (6-MP) is a well-established immunosuppressive drug. Common understanding of their immunosuppressive properties is largely limited to peripheral immune cells. However, the effect of 6-MP in the central nervous system, especially in microglia in the context of neuroinflammation is, as yet, unclear. Tumor necrosis factor-α (TNF-α) is a key cytokine of the immune system that initiates and promotes neuroinflammation. The present study aimed to investigate the effect of 6-MP on TNF-α production by microglia to discern the molecular mechanisms of this modulation.

Methods

Lipopolysaccharide (LPS) was used to induce an inflammatory response in cultured primary microglia or murine BV-2 microglial cells. Released TNF-α was measured by enzyme-linked immunosorbent assay (ELISA). Gene expression was determined by real-time reverse transcription polymerase chain reaction (RT-PCR). Signaling molecules were analyzed by western blotting, and activation of NF-κB was measured by ELISA-based DNA binding analysis and luciferase reporter assay. Chromatin immunoprecipitation (ChIP) analysis was performed to examine NF-κB p65 and coactivator p300 enrichments and histone modifications at the endogenous TNF-α promoter.

Results

Treatment of LPS-activated microglia with 6-MP significantly attenuated TNF-α production. In 6-MP pretreated microglia, LPS-induced MAPK signaling, IκB-α degradation, NF-κB p65 nuclear translocation, and in vitro p65 DNA binding activity were not impaired. However, 6-MP suppressed transactivation activity of NF-κB and TNF-α promoter by inhibiting phosphorylation and acetylation of p65 on Ser276 and Lys310, respectively. ChIP analyses revealed that 6-MP dampened LPS-induced histone H3 acetylation of chromatin surrounding the TNF-α promoter, ultimately leading to a decrease in p65/coactivator-mediated transcription of TNF-α gene. Furthermore, 6-MP enhanced orphan nuclear receptor Nur77 expression. Using RNA interference approach, we further demonstrated that Nur77 upregulation contribute to 6-MP-mediated inhibitory effect on TNF-α production. Additionally, 6-MP also impeded TNF-α mRNA translation through prevention of LPS-activated PI3K/Akt/mTOR signaling cascades.

Conclusions

These results suggest that 6-MP might have a therapeutic potential in neuroinflammation-related neurodegenerative disorders through downregulation of microglia-mediated inflammatory processes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-016-0543-5) contains supplementary material, which is available to authorized users.