LPS-induced CCL2 Research Articles

Particles in Raw Sheep Milk Can Modulate the Inflammatory Response in THP-1, a Human Monocyte Cell Line, In Vitro

Background: The UK dairy sheep industry is relatively small but growing, particularly for cheese and yogurt products. Anecdotally, sheep milk (SM) may be better tolerated by humans than cows’ milk and could have environmental as well as health benefits. All milk contains sub-micron particles called extracellular vesicles (EVs) which are mainly derived from the mammary epithelium. Physiologically, milk-derived EVs are thought to aid in the development of infant immunity and the microbiome, but may also have health benefits to adult humans. The purpose of this study was to determine whether EVs could be isolated from raw sheep milk and whether they have any effect on inflammatory responses in THP-1, a human monocyte cell line, in vitro. Methods: Using sequential ultracentrifugation, vesicles of <1 µm (LEV) followed by <200 nm (sEVs) were isolated from six individual sheep during mid-lactation. RNA was extracted and microRNA analyzed by RTqPCR for sequences previously identified in cows’ milk. Human THP-1 monocytes were differentiated into macrophages and incubated with SM-derived LEVs and sEVs in the presence of pro-inflammatory LPS to measure the effects on the secretion of the chemokine CCL-2 or in the presence of DMNQ and fluorescent dihydrorhodamine-1,2,3 to measure reactive oxygen species. Results: LEVs induced an increase in ROS in both monocytes and macrophages, whilst sEVs decreased DMNQ-mediated ROS in macrophages but not monocytes. Interestingly, the LEVs did not induce CCL2 release; however, they increased LPS-induced CCL2 secretion in monocytes but not macrophages. miR26a, miR92a, miR125b, miR155 and miR223 were identified in both sEVs and LEVs by RT-qPCR and could be responsible for the modulation of ROS and CCL2 expression. Conclusions: These findings suggest that like cows’ milk, sheep milk contains EVs, and they can influence human monocyte/macrophage responses, and so is worthy of further investigation for its potential human- and non-human-animal health benefits.

Notch signaling is activated in knee-innervating dorsal root ganglia in experimental models of osteoarthritis joint pain

BackgroundWe aimed to explore activation of the Notch signaling pathway in knee-innervating lumbar dorsal root ganglia (DRG) in the course of experimental osteoarthritis (OA) in mice, and its role in knee hyperalgesia.MethodsCultured DRG cells were stimulated with the TLR4 agonist, lipopolysaccharide (LPS). Notch signaling in the cells was either inhibited with the γ-secretase inhibitor, DAPT, or with soluble Jagged1, or activated through immobilized Jagged1. CCL2 production was analyzed at mRNA and protein levels. In in vivo experiments, knee hyperalgesia was induced in naïve mice through intra-articular (IA) injection of LPS. The effect of inhibiting Notch signaling was examined by pre-injecting DAPT one hour before LPS. OA was induced through surgical destabilization of the medial meniscus (DMM) in male C57BL/6 mice. Gene expression in DRG was analyzed by qRT-PCR and RNAscope in situ hybridization. Activated Notch protein (NICD) expression in DRG was evaluated by ELISA and immunofluorescence staining. DAPT was injected IA 12 weeks post DMM to inhibit Notch signaling, followed by assessing knee hyperalgesia and CCL2 expression in the DRG.ResultsIn DRG cell cultures, LPS increased NICD in neuronal cells. Inhibition of Notch signaling with either DAPT or soluble Jagged1 attenuated LPS-induced increases of Ccl2 mRNA and CCL2 protein. Conversely, activating Notch signaling with immobilized Jagged1 enhanced these LPS effects. In vivo, IA injection of LPS increased expression of Notch genes and NICD in the DRG. Pre-injection of DAPT prior to LPS alleviated LPS-induced knee hyperalgesia, and decreased LPS-induced CCL2 expression in the DRG. Notch signaling genes were differentially expressed in the DRG from late-stage experimental OA. Notch1, Hes1, and NICD were increased in the neuronal cell bodies in DRG after DMM surgery. IA administration of DAPT alleviated knee hyperalgesia post DMM, and decreased CCL2 expression in the DRG.ConclusionsThese findings suggest a synergistic effect of Notch signaling with TLR4 in promoting CCL2 production and mediating knee hyperalgesia. Notch signaling is activated in knee-innervating lumbar DRG in mice with experimental OA, and is involved in mediating knee hyperalgesia. The pathway may therefore be explored as a target for alleviating OA pain.

Role of heat shock protein 70 in regulation of anti-inflammatory response to curcumin in 3T3-L1 adipocytes.

Curcumin is a well-known phytochemical with anti-inflammatory effects. Heat shock protein (HSP) 70, an intracellular chaperone, inhibits proinflammatory signaling activation. Although curcumin has been shown to induce HSP70 expression in various cell types, whether HSP70 mediates the anti-inflammatory effects of curcumin in mature adipocytes remains unclear. To assess the role of HSP70 in regulating the anti-inflammatory response to curcumin in adipocytes, fully differentiated 3T3-L1 adipocytes were treated with curcumin, lipopolysaccharide (LPS), and/or the HSP70 inhibitor pifithrin-μ (PFT-μ). The expression levels of HSP70 and proinflammatory cytokines were then measured. Curcumin upregulated HSP70 expression at both protein and mRNA levels and attenuated LPS-induced Il6, Ptx3, and Ccl2 mRNA upregulation. PFT-μ tended to exacerbate the LPS-induced upregulation of Il6, Ptx3, Ccl2, and Tnfa mRNA expression. However, on curcumin pretreatment, the tendency of PFT-μ to upregulate LPS-induced proinflammatory cytokine expression decreased or disappeared. These results indicate that HSP70 is involved in the regulation of inflammatory responses but may not be crucial for the anti-inflammatory effects of curcumin in 3T3-L1 adipocytes.

Anti-inflammatory aromadendrane- and cadinane-type sesquiterpenoids from the South China Sea sponge Acanthella cavernosa.

One new aromadendrane-type sesquiterpenoid, namely ximaocavernosin P [(+)-1], and three new cadinane-type sesquiterpenoids, namely (+)-maninsigin D [(+)-4], (+)- and (−)-ximaocavernosin Q [(+)- and (−)-5], together with five related known ones [2, 3, (−)-4, 6, and 7], were isolated from the Hainan sponge Acanthella cavernosa. Compounds 4 and 5 were isolated as racemic forms, which were further separated to the corresponding enantiomers [(+)-4/(−)-4 and (+)-5/(−)-5], respectively, by using chiral-phase HPLC. The structures of new compounds were elucidated by extensive spectroscopic analysis and comparison with the reported data. In addition, the absolute configuration of optically pure (+)-1 and 2 were determined by time-dependent density functional theory/electronic circular dichroism (TDDFT-ECD) calculations or X-ray diffraction analysis. A plausible biosynthetic pathway of these sesquiterpenoids and their internal correlation were proposed and discussed. In an in vitro bioassay, (+)-aristolone (3) exhibited promising anti-inflammatory activity by the inhibition of LPS-induced TNF-α and CCL2 release in RAW 264.7 macrophages.

Coffee ingredients, hydroquinone, pyrocatechol, and 4-ethylcatechol exhibit anti-inflammatory activity through inhibiting NF-κB and activating Nrf2

• ・Pyrocatechol is the main coffee ingredient exhibiting anti-inflammatory activity. • ・Hydroquinone and 4-ethylcatechol in coffee exhibit anti-inflammatory activity. • ・Pyrocatechol, hydroquinone and 4-ethylcatechol inhibit NF-κB activation. • ・Pyrocatechol, hydroquinone and 4-ethylcatechol activate Nrf2. Pyrocatechol is a coffee ingredient that exhibits anti-inflammatory activity. We herein identified hydroquinone and 4-ethylcatechol as novel coffee ingredients inhibiting LPS-induced inflammatory responses. Similar to pyrocatechol, hydroquinone and 4-ethylcatechol significantly inhibited LPS-induced nitric oxide (NO) production and CCL2 secretion by suppressing the mRNA expression of iNOS and CCL2 in murine macrophage-like RAW264.7 cells. These ingredients also inhibited the LPS-induced activation of NF-κB, a pivotal transcription factor in inflammation, by preventing its nuclear localization, and induced the expression of Nrf2, a transcription factor negatively regulating LPS-induced inflammation. By utilizing Keap1 −/− MEFs reconstituted with Keap1 mutants in which major cysteine residues were substituted, we found that Cys151 in Keap1 was a critical sensor for pyrocatechol, hydroquinone, and 4-ethylcatechol to induce Nrf2 expression. However, the amounts of hydroquinone and 4-ethylcatechol in the coffee decoction were markedly lower than that of pyrocatechol, suggesting that pyrocatechol is the main coffee ingredient exhibiting anti-inflammatory activity.

LncRNA CAIF suppresses LPS-induced inflammation and apoptosis of cardiomyocytes through regulating miR-16 demethylation.

BackgroundThe long noncoding RNA, cardiac autophagy inhibitory factor (CAIF), and microRNA (miR)‐16 are reported to be involved in lipopolysaccharide (LPS)‐induced inflammatory responses and cell apoptosis in many diseases. Herein, we investigated the interaction between CAIF and miR‐16 in sepsis‐induced chronic heart failure (CHF).MethodsThe expression of CAIF and miR‐16 in plasma samples from sepsis‐induced CHF patients (n = 60) and healthy controls (n = 60) were measured using quantitative reverse‐transcription polymerase chain reaction (qRT‐PCR). The correlations between CAIF and miR‐16 across plasma samples from patients with sepsis‐induced CHF and healthy controls were analyzed using linear regression. The messenger RNA (mRNA) levels of inducible nitric oxide synthase, C‐C motif chemokine 2 (CCL2), growth‐regulated alpha protein (CXCL1), and interleukin‐6 (IL‐6) were evaluated using qRT‐PCR while nuclear factor κB activation was evaluated using luciferase assay.ResultsThe expression levels of CAIF and miR‐16 were downregulated in the plasma of sepsis‐induced CHF patients and were positively correlated in these patients. In cardiomyocytes, LPS treatment dose‐dependently decreased CAIF and miR‐16 levels. CAIF overexpression increased miR‐16 expression by demethylating miR‐16. CAIF and/or miR‐16 overexpression suppressed LPS‐induced CCL2, CXCL1, and IL‐6 expression at both the mRNA and protein levels. Analysis of cell apoptosis and western blot analysis showed that CAIF and/or miR‐16 overexpression inhibited LPS‐induced cardiomyocyte apoptosis by reducing Bax and cleaved caspase 3 levels and enhancing Bcl‐2 levels.ConclusionOur study is the first to report the abnormal expression of CAIF and miR‐16 in heart disease. CAIF plays a protective role in sepsis‐induced CHF by inhibiting cardiomyocyte apoptosis and inflammation, possibly by regulating miR‐16 demethylation.

Pathogenic Functions of Tumor Necrosis Factor Receptor-Associated Factor 6 Signaling Following Traumatic Brain Injury.

Neuroinflammation contributes to delayed (secondary) neurodegeneration following traumatic brain injury (TBI). Tumor necrosis factor receptor-associated factor 6 (TRAF6) signaling may promote post-TBI neuroinflammation, thereby exacerbating secondary injury. This study investigated the pathogenic functions of TRAF6 signaling following TBI in vivo and in vitro. A rat TBI model was established by air pressure contusion while lipopolysaccharide (LPS) exposure was used to induce inflammatory-like responses in cultured astrocytes. Model rats were examined for cell-specific expression of TRAF6, NF-κB, phosphorylated (p)-NF-κB, MAPKs (ERK, JNK, and p38), p-MAPKs, chemokines (CCL2 and CXCL1), and chemokine receptors (CCR2 and CXCR2) by immunofluorescence, RT-qPCR, western blotting, and ELISA, for apoptosis by TUNEL staining, and spatial cognition by Morris water maze testing. These measurements were compared between TBI model rats receiving intracerebral injections of TRAF6-targeted RNAi vector (AAV9-TRAF6-RNAi), empty vector, MAPK/NF-κB inhibitors, or vehicle. Primary astrocytes were stimulated with LPS following TRAF6 siRNA or control transfection, and NF-κB, MAPKs, chemokine, and chemokine receptor expression levels evaluated by western blotting and ELISA. TRAF6 was expressed mainly in astrocytes and neurons of injured cortex, peaking 3 days post-TBI. Knockdown by AAV9-TRAF6-RNAi improved spatial learning and memory, decreased TUNEL-positive cell number in injured cortex, and downregulated expression levels of p-NF-κB, p-ERK, p-JNK, p-p38, CCL2, CCR2, CXCL1, and CXCR2 post-TBI. Inhibitors of NF-κB, ERK, JNK, and p38 significantly suppressed CCL2, CCR2, CXCL1, and CXCR2 expression following TBI. Furthermore, TRAF6-siRNA inhibited LPS-induced NF-κB, ERK, JNK, p38, CCL2, and CXCL1 upregulation in cultured astrocytes. Targeting TRAF6-MAPKs/NF-κB-chemokine signaling pathways may provide a novel therapeutic approach for reducing post-TBI neuroinflammation and concomitant secondary injury.

Mas receptor activation attenuates allergic airway inflammation via inhibiting JNK/CCL2-induced macrophage recruitment

BackgroundDefective absorption of acute allergic airway inflammation is involved in the initiation and development of chronic asthma. After allergen exposure, there is a rapid recruitment of macrophages around the airways, which promote acute inflammatory responses. The Ang-(1−7)/Mas receptor axis reportedly plays protective roles in various tissue inflammation and remodeling processes in vivo. However, the exact role of Mas receptor and their underlying mechanisms during the pathology of acute allergic airway inflammation remains unclear. ObjectiveWe investigated the role of Mas receptor in acute allergic asthma and explored its underlying mechanisms in vitro, aiming to find critical molecules and signal pathways. MethodsMas receptor expression was assessed in ovalbumin (OVA)-induced acute asthmatic murine model. Then we estimated the anti-inflammatory role of Mas receptor in vivo and explored expressions of several known inflammatory cytokines as well as phosphorylation levels of MAPK pathways. Mas receptor functions and underlying mechanisms were studied further in the human bronchial epithelial cell line (16HBE). ResultsMas receptor expression decreased in acute allergic airway inflammation. Multiplex immunofluorescence co-localized Mas receptor and EpCAM, indicated that Mas receptor may function in the bronchial epithelium. Activating Mas receptor through AVE0991 significantly alleviated macrophage infiltration in airway inflammation, accompanied with down-regulation of CCL2 and phosphorylation levels of MAPK pathways. Further studies in 16HBE showed that AVE0991 pre-treatment inhibited LPS-induced or anisomycin-induced CCL2 increase and THP-1 macrophages migration via JNK pathways. ConclusionOur findings suggested that Mas receptor activation significantly attenuated CCL2 dependent macrophage recruitments in acute allergic airway inflammation through JNK pathways, which indicated that Mas receptor, CCL2 and phospho-JNK could be potential targets against allergic airway inflammation.

BK Channels Regulate LPS-induced CCL-2 Release from Human Pulmonary Endothelial Cells.

We recently established a role for the stretch-activated two-pore-domain K+ (K2P) channel TREK-1 (K2P2.1) in inflammatory cytokine secretion using models of hyperoxia-, mechanical stretch-, and TNF-α-induced acute lung injury. We have now discovered the expression of large conductance, Ca2+-activated K+ (BK) channels in human pulmonary microvascular endothelial cells and primary human alveolar epithelial cells using semiquantitative real-time PCR, IP and Western blot, and investigated their role in inflammatory cytokine secretion using an LPS-induced acute lung injury model. As expected, LPS induced IL-6 and CCL-2 secretion from pulmonary endothelial and epithelial cells. BK activation with NS1619 decreased LPS-induced CCL-2 but not IL-6 secretion from endothelial cells and had no effect on epithelial cells, although fluorometric assays revealed that BK activation hyperpolarized the plasma membrane potential (Em) of both cell types. Interestingly, BK inhibition (Paxilline) did not alter cytokine secretion or the Em in either cell type. Furthermore, LPS treatment by itself did not affect the Em or intracellular Ca2+ concentrations. Therefore, we propose BK channel activation as a novel targeted approach to counteract LPS-induced CCL-2 secretion from endothelial cells. This protective effect appears to occur via Em hyperpolarization but independent of intracellular Ca2+ concentrations.

Prostaglandin E2 Affects Interleukin 6 and Monocyte Chemoattractant Protein 1/CCL2 Production by Cultured Stem Cells of Apical Papilla

IntroductionRoot canal treatment of immature necrotic teeth is a major challenge in current endodontics. The effect of inflammatory mediators, such as prostaglandin, on the modulation of stem cells of the apical papilla (SCAP) is not completely understood. The aim of this study was to investigate the role of prostaglandin E2 (PGE2) on SCAP activation by Escherichia coli lipopolysaccharide (LPS) in vitro. MethodsSCAP cultures were established and characterized. Increasing concentrations of lipopolysaccharide (0.1–10 μg/mL) were used to investigate cyclooxygenase-2 (COX-2/PTGS2) and PGE2 receptors (EP1–4) gene expression. Then, SCAP were treated with a COX-2 inhibitor (indomethacin) before treatment with different concentrations of LPS. The levels of the chemokine CCL2/monocyte chemoattractant protein 1 and interleukin (IL)-6 were detected in cell supernatants (24 hours) by enzyme-linked immunosorbent assay. Data analysis was performed using analysis of variance followed by the Tukey post test. ResultsThe expression of COX-2 was up-regulated in the group treated with LPS at 1μg/mL compared with that in the control group. EP1–4 were detected in all experimental conditions at similar levels. SCAP treated with indomethacin presented a down-regulation in the production of LPS-induced CCL2 and the secretion of IL-6. ConclusionsSCAP showed increased COX-2 (PTGS2) gene expression induced by LPS and a PGE2-dependent production of IL-6 and CCL2.

Morin alleviates LPS-induced mastitis by inhibiting the PI3K/AKT, MAPK, NF-κB and NLRP3 signaling pathway and protecting the integrity of blood-milk barrier

Mastitis is a common veterinary clinical disease that restricts the development of dairy farming around the world. Morin, extracted from Mulberry Tree and other herbs, has been reported to possess the function of anti-bacteria, anti-oxidant, and anti-inflammatory. However, whether morin could protect lipopolysaccharide (LPS)-induced mouse mastitis in vivo has not well known. This study firstly aims to evaluate the effects of morin on LPS-induced mouse mastitis in vivo, and then try to illustrate the mechanism involved in the process. Before injected with LPS, mice were intraperitoneally pre-injected with different concentrations of morin, and mice of the control and LPS group were injected with the same amount of saline. Pathologic changes of mammary gland were determined by histopathological examination. Myeloperoxidase (MPO) activities of mammary gland were determined by the MPO kits. The mRNA expressions of inflammatory cytokines including TNF-α, IL-1β and IL-6, and those of chemokine factors CCL2 and CXCL2, and those of tight junctions occludin claudin-3 were examined by qRT-PCR analysis. The activities of IκB, p65, ERK, P38, AKT, PI3K, NLPR3, claudin-1, claudin-3 and occludin were determined by western blotting. The results showed that morin alleviated LPS-induced edema, destructed structures and infiltrated inflammatory cells of mammary gland. Morin administration significantly decreased LPS-induced TNF-α, IL-1β, IL-6, CCL2 and CXCL2 mRNA expressions. Furthermore, western blot analysis also showed that morin significantly reduced LPS-induced phosphorylation of p65, IκB, p38 and ERK, and enhanced LPS-induced phosphorylation of AKT and PI3K. It was also found that LPS-decreased claudin-3 and occludin expressions were also inhibited by morin treatment. In summary, above results suggest that morin indeed protect LPS-induced mouse mastitis in vivo, and the mechanism was through inhibiting the PI3K/AKT, MAPK, NF-κB and NLRP3 signaling pathways and protecting the integrity of blood-milk barrier by regulating the tight junction proteins expressions.

Proinflammatory profile of neonatal monocytes induced by microbial ligands is downmodulated by histamine

Although the neonatal period is characterized by relative immunological immaturity, an inflammatory response due to Toll-like receptor (TLR) activation is observed. Histamine may be one of the factors playing a role in restraining inflammation during the early stages of life. Therefore, we evaluated the responsiveness of human cord blood cells to TLR4 agonists and the immunomodulatory function of histamine in the inflammatory response. Compared with adults, mononuclear cells (MNCs) from newborns (NBs) exhibit impaired production of IFN-γ-inducible chemokines, such as CXCL10 and CXCL9, upon lipopolysaccharide (LPS) stimulation. Notably, LPS induced a 5-fold increase in CCL2 secretion in NBs. Evaluation of the effect of histamine on LPS-induced CCL2 secretion showed an inhibitory effect in the majority of adults, whereas this effect was detectable in all NBs. Histamine receptor (HR) blockage revealed partial involvement of H1R, H2R and H4R in LPS-induced CCL2 inhibition in MNCs from both NBs and adults. As monocytes are the main type of mononuclear cell that produces CCL2, we evaluated genes related to TLR signaling upon LPS stimulation. Monocytes from NBs showed up-regulation of genes associated with JAK/STAT/NF-κB and IFN signaling. Some differentially expressed genes encoding proinflammatory factors were preferentially detected in LPS-activated monocytes from NBs, and markedly down-regulated by histamine. The immunomodulatory role of histamine on CCL2 and CXCL8 was detected at the transcript and protein levels. Our findings show that NBs have enhanced CCL2 responsiveness to LPS, and that histamine acts in immune homeostasis during the neonatal period to counterbalance the robustness of TLR stimulation.

The autophagy receptor SQSTM1/p62 mediates anti-inflammatory actions of the selective NR3C1/glucocorticoid receptor modulator compound A (CpdA) in macrophages

ABSTRACTGlucocorticoids are widely used to treat inflammatory disorders; however, prolonged use of glucocorticoids results in side effects including osteoporosis, diabetes and obesity. Compound A (CpdA), identified as a selective NR3C1/glucocorticoid receptor (nuclear receptor subfamily 3, group C, member 1) modulator, exhibits an inflammation-suppressive effect, largely in the absence of detrimental side effects. To understand the mechanistic differences between the classic glucocorticoid dexamethasone (DEX) and CpdA, we looked for proteins oppositely regulated in bone marrow-derived macrophages using an unbiased proteomics approach. We found that the autophagy receptor SQSTM1 but not NR3C1 mediates the anti-inflammatory action of CpdA. CpdA drives SQSTM1 upregulation by recruiting the NFE2L2 transcription factor to its promoter. In contrast, the classic NR3C1 ligand dexamethasone recruits NR3C1 to the Sqstm1 promoter and other NFE2L2-controlled gene promoters, resulting in gene downregulation. Both DEX and CpdA induce autophagy, with marked different autophagy characteristics and morphology. Suppression of LPS-induced Il6 and Ccl2 genes by CpdA in macrophages is hampered upon Sqstm1 silencing, confirming that SQSTM1 is essential for the anti-inflammatory capacity of CpdA, at least in this cell type. Together, these results demonstrate how off-target mechanisms of selective NR3C1 ligands may contribute to a more efficient anti-inflammatory therapy.

TLR4/MyD88 -mediated CCL2 production by lipopolysaccharide (endotoxin): Implications for metabolic inflammation.

BackgroundObese human and mice were reported to have higher circularity endotoxin (LPS) levels as compared to their lean counter parts. The current study was aimed to reveal the molecular mechanisms underlying the LPS mediated induction of CCL2 in human monocytes/macrophages.MethodsHuman monocytic cell line THP-1, THP-1 cells derived macrophages and primary macrophages were treated with LPS and TNF-α (positive control). CCL2 expression was determined with real-time RT-PCR and ELISA. THP-1-XBlue™ cells, THP-1-XBlue™-defMyD cells, TLR4 neutralization antibody, TLR4 siRNA and inhibitors for NF-kB and MAPK were used to study the signaling pathways. Phosphorylation of NF-kB and c-Jun was analyzed by ELISA.ResultsLPS upregulates CCL2 expression at both mRNA (THP-1: 23.40 ± .071 Fold, P < 0.0001; THP-1-derived macrophages: 103 ± 0.56 Fold, < 0.0001; Primary macrophages: 48 ± 1.41 Fold, P < 0.0005) and protein (THP1 monocytes:1048 ± 5.67 pg/ml, P < 0.0001; THP-1-derived macrophages; 2014 ± 2.12, P = 0.0001; Primary macrophages: 859.5 ± 3.54, P < 0.0001) levels in human monocytic cells/macrophages. Neutralization of TLR4 blocked LPS-induced CCL-2 secretion (P < 0.0001). Silencing of TLR4 by siRNA also significantly reduced LPS-induced CCL-2 production. Furthermore, MyD88-Knockout cells treated with LPS did not produce CCL-2. NF-kB and c-Jun phosphorylation was noted in LPS treated cells.ConclusionOverall, our data reveal that LPS induces CCL-2 in monocytes/macrophages via TLR4/MyD88 signaling which leads to the activation of NF-kB/AP-1 transcription factors.

The opioid antagonist, β-funaltrexamine, inhibits lipopolysaccharide-induced neuroinflammation and reduces sickness behavior in mice

Brain pathologies such as neurodegenerative diseases, infection, traumatic brain injury, and mood disorders produce enormous personal and economic burdens. It is well established that neuroinflammation plays an important role in the etiology and/or manifestation of such disorders. Previously, we discovered that beta-funaltrexamine (β-FNA) inhibits inflammatory signaling in human astrocytes in vitro, resulting in reduced expression of proinflammatory cytokines/chemokines. The present study examines the effects of peripherally administered β-FNA on lipopolysaccharide (LPS)-induced neuroinflammation and sickness behavior in vivo. Adult male C57BL/6J mice were administered β-FNA and were then immediately administered bacterial lipopolysaccharide (LPS). At 24h post-injections, sickness behavior was assessed in an open-field test. Following behavioral analysis plasma and brains were collected. Levels of interleukin-6 (IL-6), interferon-γ inducible protein-10 (CXCL10), and monocyte chemoattractant protein-1 (CCL2) were determined by enzyme-linked immunosorbant assay (ELISA). At 24h post-LPS injection, IL-6, CCL2 and CXCL10 were increased in the plasma, whereas, only CCL2 and CXCL10 were elevated in the brain. β-FNA significantly inhibited LPS-induced CXCL10 and CCL2 expression in brain, but minimally or not at all in the plasma. LPS-induced sickness behavior, as indicated by a reduction in distance moved, was prevented by β-FNA. Overall, CXCL10 expression in the brain was most positively and significantly correlated with sickness behavior; whereas, anxiety-like behavior was most positively and significantly correlated with IL-6 and CCL2 levels in the plasma and levels of CXCL10 and CCL2 in the brain. The reduction in sickness behavior may be in part due to decreased chemokine expression in the brain; further examination of the anti-inflammatory and neuroprotective effects of β-FNA is warranted.

Ashwagandha attenuates TNF-α- and LPS-induced NF-κB activation and CCL2 and CCL5 gene expression in NRK-52E cells.

BackgroundThe aging kidney is marked by a chronic inflammation, which may exacerbate the progression of renal dysfunction, as well as increase the susceptibility to acute injury. The identification of strategies to alleviate inflammation may have translational impact to attenuate kidney disease.MethodsWe tested the potential of ashwaganda, sutherlandia and elderberry on tumor necrosis factor-α (TNF-α) and lipopolysaccharide (LPS) induced chemokine (CCL2 and CCL5) expression in vitro.ResultsElderberry water-soluble extract (WSE) was pro-inflammatory, while sutherlandia WSE only partially attenuated the TNF-α-induced changes in CCL5. However, ashwaganda WSE completely prevented TNF-α-induced increases in CCL5, while attenuating the increase in CCL2 expression and NF-κB activation. The same pattern of ashwagandha protection was seen using LPS as the pro-inflammatory stimuli.ConclusionsTaken together, these results demonstrate the ashwaganda WSE as a valid candidate for evaluation of therapeutic potential for the treatment of chronic renal dysfunction.

MicroRNA-146a-5p attenuates neuropathic pain via suppressing TRAF6 signaling in the spinal cord

Glia-mediated neuroinflammation plays an important role in the pathogenesis of neuropathic pain. Our recent study demonstrated that TNF receptor associated factor-6 (TRAF6) is expressed in spinal astrocytes and contributes to the maintenance of spinal nerve ligation (SNL)-induced neuropathic pain. MicroRNA (miR)-146a is a key regulator of the innate immune response and was shown to target TRAF6 and reduce inflammation. In this study, we found that in cultured astrocytes, TNF-α, IL-1β, or lipopolysaccharide (LPS) induced rapid TRAF6 upregulation and delayed miR-146a-5p upregulation. In addition, miR-146a-5p mimic blocked LPS-induced TRAF6 upregulation, as well as LPS-induced c-Jun N-terminal kinase (JNK) activation and chemokine CCL2 expression in astrocytes. Notably, LPS incubation with astrocytes enhanced the DNA binding activity of AP-1 to the promoters of mir-146a and ccl2. TRAF6 siRNA or JNK inhibitor SP600125 significantly reduced LPS-induced miR-146a-5p increase in astrocytes. In vivo, intrathecal injection of TNF-α or LPS increased spinal TRAF6 expression. Pretreatment with miR-146a-5p mimic alleviated TNF-α- or LPS-induced mechanical allodynia and reduced TRAF6 expression. Finally, SNL induced miR-146a-5p upregulation in the spinal cord at 10 and 21days. Intrathecal injection of miR-146a-5p mimic attenuated SNL-induced mechanical allodynia and decreased spinal TRAF6 expression. Taken together, the results suggest that (1) miR-146a-5p attenuates neuropathic pain partly through inhibition of TRAF6 and its downstream JNK/CCL2 signaling, (2) miR-146a-5p is increased by the activation of TRAF6/JNK pathway. Hence, miR-146a-5p may be a novel treatment for chronic neuropathic pain.

Anti-inflammatory effect of Marchantin M contributes to sensitization of prostate cancer cells to docetaxel

As pro-inflammatory cytokines and chemokines contribute to the malignancy of many types of human cancer, we examined the anti-inflammatory effect of bisbibenzyls, a diverse bioactive group of naturally occurring compounds. Marchantin M (Mar M) was identified through a screening process of these compounds as a potent anti-inflammatory agent based on its capacity to inhibit LPS-induced IL6, IL1β and CCL2 expression in HUVECs and PBMCs without affecting cell proliferation. Since Mar M has been found to exhibit anticancer activity, we observed that Mar M treatment also resulted in decreases in the expressions of IL6, IL1β and TNFα in metastatic prostate cancer (PCa) cells. This effect was further confirmed in other cancer cell lines that express high level of pro-inflammatory cytokines. Furthermore, inactivation of NF-κB, a critical transcription factor controlling many pro-inflammatory cytokine expressions, was observed in Mar M-treated PCa cells as evidenced by decreased phosphor-p65 and subsequently phosphor-STAT3. Mar M also suppressed phosphorylation of IKBα, an inhibitor of NF-κB in the cytosol. However, reduced phosphor-p65 by Mar M was slightly increased when knockdown of IKBα, suggesting that Mar M may target upstream molecules of IKBα/NF-κB signaling. Finally, treatment with Mar M resulted in more enhanced-sensitivity of PCa cells to docetaxel-induced apoptosis than that of the IL6 blocking. Our study demonstrates the potential of the anti-inflammatory agent Mar M as an adjuvant to improve the efficacy of traditional anticancer agents such as docetaxel.

Raw264.7 Cells Secrete Fibroblast Growth Stimulating Activity after Differentiation to Macrophages by Stimulation with Lipopolysaccharide

Raw264.7 cells are monocytic cells that can differentiate to activated macrophages after lipopoly-saccharide (LPS) stimulation. Here, we analyzed the factors secreted by Raw264.7 cells in response to LPS. The culture media of LPS-treated Raw264.7 cells was able to stimulate growth in MEF1F2 and NIH3T3 mouse fibroblast cell lines. We identified five secreted and LPS-induced chemokines, CCL2, CCL5, CCL12, CxCL2, and CxCL10, by microarray analysis and tested their stimulatory activity. We used commercially available bacterially expressed proteins, and found only CCL12, CxCL2 and CxCL10 stimulated growth in MEF1F2 and NIH3T3 cells. The saturation density of the cells was also increased. They were not able to stimulate growth in v-Src transformed MEF1F2 or SWAP-70 transformed NIH3T3 cells. We examined signaling pathways activated by these three factors. We found that ERK and p38 MAP kinase were activated and were required for the activity to stimulate the cell growth. Other pathways including phosophatidylinositol-3 kinase (PI3K), NFκB pathways were not activated. These results suggest that Raw264.7 cells secretes growth stimulation factors for fibroblasts when differentiated to macrophages implicating that fast growth of them is related to inflamation although the reason is still unclear.

Huperzine A Inhibits CCL2 Production in Experimental Autoimmune Encephalomyelitis Mice and in Cultured Astrocyte

The active role of chemokines and inflammatory cytokines in the central nervous system (CNS) during the pathogenesis of experimental autoimmune encephalomyelitis (EAE) has been clearly established. Recent studies from our laboratory reported that Huperzine A (HupA) can attenuate the disease process in EAE by the inhibition of inflammation, demyelination, and axonal injury in the spinal cord as well as encephalomyelitic T-cell proliferation. In this study, the effects of low dose HupA on CCL2, TNF-alpha, IL-6, and IL-1beta expression were evaluated in EAE. The effect of HupA on lipopolysachharide (LPS)-induced inflammatory molecule secretion was investigated in cultured-astrocytes in vitro. In MOG35-55-induced EAE mice, intraperitoneal injections of HupA (0.1 mg/kg•d−1) significantly suppressed the expression of CCL2, IL-6, TNF-alpha, and IL-1beta in the spinal cord. HupA also repressed LPS-induced CCL2 production, but with little influence on pro-inflammatory cytokines in primary cultured astrocytes. The inhibition effect of HupA on CCL2 is PPARgamma-dependent and nicotine receptor-independent. Conditioned culture media from HupA-treated astrocyte decreased PBMC migration in vitro. Collectively, these results suggest that HupA can ameliorate EAE by inhibiting CCL2 production in astrocyte, which may consequently decrease inflammatory cell infiltration in the spinal cord. HupA may have a potential therapeutic value for the treatment of MS and other neuroinflammatory diseases.