Mediators In Lipopolysaccharide Research Articles

Saponins from Allium macrostemon Bulbs Attenuate Endothelial Inflammation and Acute Lung Injury via the NF-κB/VCAM-1 Pathway.

Endothelial inflammation is a multifaceted physiological process that plays a pivotal role in the pathogenesis and progression of diverse diseases, encompassing but not limited to acute lung infections like COVID-19, coronary artery disease, stroke, sepsis, metabolic syndrome, certain malignancies, and even psychiatric disorders such as depression. This inflammatory response is characterized by augmented expression of adhesion molecules and secretion of pro-inflammatory cytokines. In this study, we discovered that saponins from Allium macrostemon bulbs (SAMB) effectively inhibited inflammation in human umbilical vein endothelial cells induced by the exogenous inflammatory mediator lipopolysaccharide or the endogenous inflammatory mediator tumor necrosis factor-α, as evidenced by a significant reduction in the expression of pro-inflammatory factors and vascular cell adhesion molecule-1 (VCAM-1) with decreased monocyte adhesion. By employing the NF-κB inhibitor BAY-117082, we demonstrated that the inhibitory effect of SAMB on VCAM-1 expression may be attributed to the NF-κB pathway's inactivation, as characterized by the suppressed IκBα degradation and NF-κB p65 phosphorylation. Subsequently, we employed a murine model of lipopolysaccharide-induced septic acute lung injury to substantiate the potential of SAMB in ameliorating endothelial inflammation and acute lung injury in vivo. These findings provide novel insight into potential preventive and therapeutic strategies for the clinical management of diseases associated with endothelial inflammation.

Biogenic derived nanoparticles modulate mitochondrial function in cardiomyocytes.

Preservation of mitochondrial functionality is essential for heart hemostasis and cardiovascular diseases treatment. However, the current nanomedicines including liposomes, polymers and inorganic nanomaterials are severely hindered by poor stability, high manufacturing costs and potential biotoxicity. In this research, we present novel polyphenolic nanoparticles (NPs) derived from naturally occurring pomegranate peel (PP, labelled as PPP NPs), which exhibit potent antioxidative and anti-inflammatory properties, serving as a modulator of mitochondrial function. PPP NPs have been identified to improve survival rates in models of mitochondrial depletion through enhancement of cardiomyocyte proliferation and the reduction of DNA damage. Moreover, PPP NPs can effectively inhibit the production of reactive oxygen species and inflammatory mediators in lipopolysaccharide (LPS)-induced mitochondrial damage. Utilizing human engineered heart tissue and mice models, PPP NPs were found to significantly improve contractile function and alleviate inflammation activities after LPS treatment. Mechanically, PPP NPs regulated inflammatory responses via a m6A dependent manner, as determined using RNA-seq and MeRIP-seq analyses. Collectively, these insights underscore the potential of PPP NPs as a novel therapeutic approach for mitochondrial dysfunction.

Bmal1 haploinsufficiency impairs fear memory and modulates neuroinflammation via the 5-HT2C receptor.

BMAL1, a key regulator of circadian rhythms, plays a multifaceted role in brain function. However, the complex interplay between BMAL1, memory, neuroinflammation, and neurotransmitter regulation remains poorly understood. To investigate these interactions, we conducted a study using BMAL1-haplodeficient mice (BMAL1+/-). We exposed BMAL1+/- mice to behavioral assessments including cued fear conditioning, new objection recognition (NOR) test, and Y-maze test to evaluate BMAL1+/- haplodeficiency impact on memory. Furthermore, biochemical changes were analyzed through western blotting, and ELISA to explore further the mechanism of BMAL1+/- in memory, and neuroinflammation. We found that BMAL1 haploinsufficiency led to deficits in cued fear learning and memory, while spatial memory and object recognition remained intact. Further analysis revealed dysregulated neurotransmitter levels and alterations in neurotransmitter-related proteins in the prefrontal cortex of BMAL1+/- mice. Pharmacological interventions targeting dopamine uptake or the 5-HT2C receptor demonstrated that inhibiting the 5-HT2C receptor could rescue fear learning and memory impairments in BMAL1+/- mice. Additionally, we observed downregulation of the inflammasome and neuroinflammation pathways in BMAL1+/- mice, which is validated by inflammation mediator lipopolysaccharide (LPS) administration. These findings highlight that BMAL1 haploinsufficiency leads to deficits in fear learning and memory, which are linked to alterations in neurotransmitters and receptors, particularly the 5-HT2C receptor. Targeting the 5-HT2C receptor may offer a potential therapeutic strategy for mitigating cognitive impairments associated with BMAL1 dysfunction.

Anti-inflammatory effect of two pomegranate seed oils obtained by green technologies in Caco-2 cells using the bioaccessible fraction from in vitro gastrointestinal digestion

Pomegranate seeds contain up to 20% oil with a high content of punicic acid (85%), which is responsible for several biological activities. In this work, two pomegranate oils obtained by a two-step sequential extraction, first with an expeller and then via supercritical CO2 technologies, have been studied in a static gastrointestinal in vitro digestion model to evaluate their bioaccessibility. The micellar phases obtained were evaluated by an in vitro model of intestinal inflammation and Caco-2 cells exposed to the inflammatory mediator lipopolysaccharide (LPS). Inflammatory response was assessed by measuring the production of interleukins IL-6 and IL-8, and tumor necrosis factor α (TNF-α), and by evaluating the monolayer integrity. The results obtained indicate that expeller pomegranate oil (EPO) provides the highest amount of micellar phase (ca. 93%) with free fatty acids and monoacylglycerols as major components. The micellar phase obtained with supercritical CO2 pomegranate oil (SCPO) is ca. 82% with similar lipid composition. Micellar phases of EPO and SCPO showed high stability and adequate particle size. EPO shows an anti-inflammatory response, reducing the production of IL-6, IL-8 and TNF-α in LPS stimulated caco-2 cells and increasing the integrity of the cell monolayer as measured by transepithelial electrical resistance (TEER). In the case of SCPO, the anti-inflammatory effect was only evident for IL-8. The present work demonstrates good digestibility, bioaccessibility and anti-inflammatory response of both EPO and SCPO oils.

Gintonin, a Panax ginseng-derived LPA receptor ligand, attenuates kainic acid-induced seizures and neuronal cell death in the hippocampus via anti-inflammatory and anti-oxidant activities

BackgroundGintonin (GT), a Panax ginseng-derived lysophosphatidic acid receptor (LPAR) ligand, has positive effects in cultured or animal models for Parkinson's disease, Huntington's disease, and so on. However, the potential therapeutic value of GT in treating epilepsy has not yet been reported. MethodsEffects of GT on epileptic seizure (seizure) in kainic acid [KA, 55mg/kg, intraperitoneal (i.p.)]-induced model of mice, excitotoxic (hippocampal) cell death in KA [0.2 μg, intracerebroventricular (i.c.v.)]-induced model of mice, and levels of proinflammatory mediators in lipopolysaccharide (LPS)-induced BV2 cells were investigated. ResultsAn i.p. injection of KA into mice produced typical seizure. However, it was significantly alleviated by oral administration of GT in a dose-dependent manner. An i.c.v. injection of KA produced typical hippocampal cell death, whereas it was significantly ameliorated by administration of GT, which was related to reduced levels of neuroglial (microglia and astrocyte) activation and proinflammatory cytokines/enzymes expression as well as increased level of the Nrf2-antioxidant response via the upregulation of LPAR 1/3 in the hippocampus. However, these positive effects of GT were neutralized by an i.p. injection of Ki16425, an antagonist of LPA1-3. GT also reduced protein expression level of inducible nitric-oxide synthase, a representative proinflammatory enzyme, in LPS-induced BV2 cells. Treatment with conditioned medium clearly reduced cultured HT-22 cell death. ConclusionTaken together, these results suggest that GT may suppress KA-induced seizures and excitotoxic events in the hippocampus through its anti-inflammatory and antioxidant activities by activating LPA signaling. Thus, GT has a therapeutic potential to treat epilepsy.

Gastrodin Regulates the Notch-1 Signal Pathway via Renin-Angiotensin System in Activated Microglia.

Notch-1 and renin angiotensin system (RAS) are involved in microglia activation. It has been reported that gastrodin inhibited inflammatory responses mediated by activated microglia. This study explored the possible interaction between this two pathways, and to determine whether gastrodin would exert its effects on both of them. Expression of RAS, Notch-1 signaling and proinflammatory mediators in lipopolysaccharide (LPS) activated BV-2 microglia subjected to various treatments was determined by Western blot and immunofluorescence. The protein expression of RAS, Notch-1 pathway and TNF-α and IL-1β was significantly increased in activated microglia. Exogenous Ang II markedly enhanced the expression of these biomarkers. Meanwhile, Azilsartan [a specific inhibitor of AT1 (AT1I)] inhibited the expression of Notch-1 pathway and proinflammatory cytokines. When Notch-1 signaling was inhibited with DAPT, ACE and AT1 expression remained unaffected, indicating that RAS can regulate the Notch-1 pathway in activated microglia but not reciprocally. Additionally, we showed here that gastrodin inhibited the RAS, Notch-1 pathway and inflammatory response. Remarkably, gastrodin did not exert any effect on expression of Notch-1 signaling when RAS was blocked by AT1I, suggesting that gastrodin acts on the RAS directly, not through the Notch-1 pathway. Furthermore, TNF-α and IL-1β expression was significantly increased in activated microglia treated with exogenous Ang II; the expression, however, was suppressed by gastrodin. Of note, expression of proinflammatory cytokines was further decreased in gastrodin and AT1I combination treatment. The results suggest that gastrodin acts via the RAS which regulates the Notch-1 signaling and inflammation in LPS-induced microglia.

Sex differences in the diathetic effects of shift work schedules on circulating cytokine levels and pathological outcomes of ischemic stroke during middle age

Shift work is associated with increased risk for vascular disease, including stroke- and cardiovascular-related mortality. However, evidence from these studies is inadequate to distinguish the effect of altered circadian rhythms in isolation from other risk factors for stroke associated with shift work (e.g., smoking, poor diet, lower socioeconomic status). Thus, the present study examined the diathetic effects of exposure to shifted LD cycles during early adulthood on circadian rhythmicity, inflammatory signaling and ischemic stroke pathology during middle age, when stroke risk is high and outcomes are more severe. Entrainment of circadian activity was stable in all animals maintained on a fixed light:dark 12:12 cycle but was severely disrupted during exposure to shifted LD cycles (12hr advance/5d). Following treatment, circadian entrainment in the shifted LD group was distinguished by increased daytime activity and decreased rhythm amplitude that persisted into middle-age. Circadian rhythm desynchronization in shifted LD males and females was accompanied by significant elevations in circulating levels of the inflammatory cytokine IL-17A and gut-derived inflammatory mediator lipopolysaccharide (LPS) during the post-treatment period. Middle-cerebral artery occlusion, 3 months after exposure to shifted LD cycles, resulted in greater post-stroke mortality in shifted LD females. In surviving subjects, sensorimotor performance, assessed 2- and 5-days post-stroke, was impaired in males of both treatment groups, whereas in females, recovery of function was observed in fixed but not shifted LD rats. Overall, these results indicate that early exposure to shifted LD cycles promotes an inflammatory phenotype that amplifies stroke impairments, specifically in females, later in life.

Extract of Pinus densiflora needles suppresses acute inflammation by regulating inflammatory mediators in RAW264.7 macrophages and mice

Context Pinus densiflora Siebold & Zucc. (Pinaceae) needle extracts ameliorate oxidative stress, but research into their anti-inflammatory effects is limited. Objective To investigate antioxidant and anti-inflammatory effects of a Pinus densiflora needles (PINE) ethanol extract in vitro and in vivo. Materials and methods We measured levels of reactive oxygen species (ROS), superoxide dismutase (SOD) and inflammatory mediators in lipopolysaccharide (LPS)-stimulated RAW264.7 cells at various PINE concentrations (25, 50 and 100 μg/mL; but 6.25, 12.5 and 25 μg/mL for interleukin-1β and prostaglandin E2 (PGE2)). Thirty ICR mice were randomized to six groups: vehicle, control, PINE pre-treatment (0.1, 0.3 and 1 mg/left ear for 10 min followed by arachidonic acid treatment for 30 min) and dexamethasone. The posttreatment ear thickness and myeloperoxidase (MPO) activity were measured. Results PINE 100 μg/mL significantly decreased ROS (IC50, 70.93 μg/mL, p < 0.01), SOD (IC50, 30.99 μg/mL, p < 0.05), malondialdehyde (p < 0.01), nitric oxide (NO) (IC50, 27.44 μg/mL, p < 0.01) and tumour necrosis factor-alpha (p < 0.05) levels. Interleukin-1β (p < 0.05) and PGE2 (p < 0.01) release decreased significantly with 25 μg/mL PINE. PINE 1 mg/ear inhibited LPS-stimulated expression of cyclooxygenase-2 and inducible NO synthase in RAW264.7 macrophages and significantly inhibited ear oedema (36.73–15.04% compared to the control, p < 0.01) and MPO activity (167.94–105.59%, p < 0.05). Discussion and conclusions PINE exerts antioxidant and anti-inflammatory effects by inhibiting the production of inflammatory mediators. Identified flavonoids such as taxifolin and quercetin glucoside can be attributed to effect of PINE.

Endothelial MEKK3-KLF2/4 signaling integrates inflammatory and hemodynamic signals during definitive hematopoiesis

AbstractThe hematopoietic stem cells (HSCs) that produce blood for the lifetime of an animal arise from RUNX1+ hemogenic endothelial cells (HECs) in the embryonic vasculature through a process of endothelial-to-hematopoietic transition (EHT). Studies have identified inflammatory mediators and fluid shear forces as critical environmental stimuli for EHT, raising the question of how such diverse inputs are integrated to drive HEC specification. Endothelial cell MEKK3-KLF2/4 signaling can be activated by both fluid shear forces and inflammatory mediators, and it plays roles in cardiovascular development and disease that have been linked to both stimuli. Here we demonstrate that MEKK3 and KLF2/4 are required in endothelial cells for the specification of RUNX1+ HECs in both the yolk sac and dorsal aorta of the mouse embryo and for their transition to intraaortic hematopoietic cluster (IAHC) cells. The inflammatory mediators lipopolysaccharide and interferon-γ increase RUNX1+ HECs in an MEKK3-dependent manner. Maternal administration of catecholamines that stimulate embryo cardiac function and accelerate yolk sac vascular remodeling increases EHT by wild-type but not MEKK3-deficient endothelium. These findings identify MEKK-KLF2/4 signaling as an essential pathway for EHT and provide a molecular basis for the integration of diverse environmental inputs, such as inflammatory mediators and hemodynamic forces, during definitive hematopoiesis.

Enrichment of Newly Synthesized Proteins following treatment of C2C12 Myotubes with Endotoxin and Interferon-γ.

Inflammation in muscle induces the synthesis of mediators that can impair protein synthesis and enhance proteolysis, and when sustained lead to muscle atrophy. Furthermore, muscle-derived mediators that are secreted may participate in disrupting the function of other peripheral organs. Selective identification of newly synthesized proteins can provide insight on biological processes that depend on the continued synthesis of specific proteins to maintain homeostasis as well as those proteins that are up- or down-regulated in response to inflammation. We used puromycin-associated nascent chain proteomics (PUNCH-P) to characterize new protein synthesis in C2C12 myotubes and changes resulting from their exposure to the inflammatory mediators lipopolysaccharide (LPS) and interferon (IFN)-γ for either a short (4h) or prolonged (16h) time period. We identified sequences of nascent polypeptide chains belonging to a total of 1523 proteins and report their detection from three independent samples of each condition at each time point. The identified nascent proteins correspond to approximately 15% of presently known proteins in C2C12 myotubes and are enriched in specific cellular components and pathways. A subset of these proteins was identified only in treated samples and has functional characteristics consistent with the synthesis of specific new proteins in response to LPS/IFNγ. Thus, the identification of proteins from their nascent polypeptide chains provides a resource to analyze the role of new synthesis of proteins in both protein homeostasis and in proteome responses to stimuli in C2C12 myotubes. Our results reveal a profile of actively translating proteins for specific cellular components and biological processes in normal C2C12 myotubes and a different enrichment of proteins in response to LPS/IFNγ. Collectively, our data disclose a highly interconnected network that integrates the regulation of cellular proteostasis and reveal a diverse immune response to inflammation in muscle which may underlie the concomitantly observed atrophy and be important in inter-organ communication.

Single-dose versus short-course prophylactic antibiotics for peroral endoscopic myotomy: a randomized controlled trial

Peroral endoscopic myotomy (POEM) has been recommended for achalasia treatment. To prevent the potential of infective risk, antibiotic prophylaxis is usually administered, whereas the additional need of antibiotic therapy after POEM is uncertain. The primary endpoint was to determine whether prophylaxis versus prophylaxis plus short therapy was needed after POEM. Consecutive patients scheduled for POEM were randomly assigned (1:1) to group A (prophylactic cefazolin 2 g IV) or group B (prophylaxis+ cefazolin 2 g IV× 3 followed by oral amoxicillin/clavulanate 3 g/day). Infective risk was assessed by means of host response, namely body temperature and serum levels of white blood cells and C-reactive protein; immune response (the cytokines interleukin [IL]-6, IL-1β, and tumor necrosis factor-α and microbial translocation mediators lipopolysaccharide binding protein and soluble CD14); and blood cultures at time points before (t0) and after (t1, t2) POEM. After POEM, none of the 124 enrolled patients (54.6 ± 12.6 years old; 64 men) developed any fever (body temperature: t0, 36.56± .49°C; t1, 36.53± .52°C; t2, 36.48± .41°C), without any differences between groups at any time point. Regarding systemic inflammation, no difference was reported between groups in serum levels of C-reactive protein and white blood cells. Considering microbial translocation mediated response, lipopolysaccharide binding protein (group A: t0, 1539 ± 168.6 pg/mL; t1, 1321 ± 149.1 pg/mL; t2, 2492 ± 283.2 pg/mL; group B: t0, 1318 ± 115.9 pg/mL; t1, 1492 ± 163.8 pg/mL; t2, 2600 ± 328.2 pg/mL) and soluble CD14 (group A: t0, 2.16 ± .15 μg/mL; t1, 1.89 ± .15 μg/mL; t2, 2.2 ± .15 μg/mL; group B: t0, 2.1 ± .13 μg/mL; t1, 2 ± .13 μg/mL; t2, 2.5 ± .2 μg/mL) were similar between the 2 groups; the immune response cytokines IL-6, IL-1β, and tumor necrosis factor-α also were similar in the 2 groups. In relation to blood cultures, at t1 the group B bacteremia rate was 3.2% (2/62) and group A was 1.6% (1/62) with no difference (P= .6). All subsequent blood cultures were negative at t2. According to our study, postprophylactic short-term antimicrobial therapy after POEM is not required because of a very low residual infective risk. (Clinical trial registration number: NCT03587337.).

Dissection of P2X4 and P2X7 Receptor Current Components in BV-2 Microglia.

Microglia cells represent the immune system of the central nervous system. They become activated by ATP released from damaged and inflamed tissue via purinergic receptors. Ionotropic purinergic P2X4 and P2X7 receptors have been shown to be involved in neurological inflammation and pain sensation. Whether the two receptors assemble exclusively as homotrimers or also as heterotrimers is still a matter of debate. We investigated the expression of P2X receptors in BV-2 microglia cells applying the whole-cell voltage-clamp technique. We dissected P2X4 and P2X7 receptor-mediated current components by using specific P2X4 and P2X7 receptor blockers and by their characteristic current kinetics. We found that P2X4 and P2X7 receptors are activated independently from each other, indicating that P2X4/P2X7 heteromers are not of functional significance in these cells. The pro-inflammatory mediators lipopolysaccharide and interferon γ, if applied in combination, upregulated P2X4, but not P2X7 receptor-dependent current components also arguing against phenotypically relevant heteromerization of P2X4 and P2X7 receptor subunits.

The β1-integrin plays a key role in LEC invasion in an optimized 3-D collagen matrix model.

Lymphangiogenesis, or formation of new lymphatic vessels, is a tightly regulated process that is controlled by growth factor signaling and biomechanical cues. Lymphatic endothelial cells (LECs) undergo remodeling, migration, and proliferation to invade the surrounding extracellular matrix (ECM) during both physiological and pathological lymphangiogenesis. This study optimized conditions for an in vitro three-dimensional (3-D) collagen-based model that induced LEC invasion and recapitulated physiological formation of lymphatic capillaries with lumens. Invasion of LECs was enhanced in the presence of sphingosine 1-phosphate (S1P). Effects of various known lymphangiogenic factors, vascular endothelial growth factor (VEGF)-A, basic fibroblast growth factor (bFGF), interleukin (IL)-8, and hepatocyte growth factor (HGF), were tested on LEC sprout formation synergistically with VEGF-C. Several of these growth factors significantly enhanced LEC invasion, and synergistic effects of some of these further enhanced the sprouting density and lumen volume. To determine the contribution of specific ECM components, we analyzed the expression of different integrin subunits. Basal expressions of the integrin α5- and integrin β1-subunits were high in LECs. The addition of fibronectin, which mediates cellular responses through these integrins, enhanced LEC sprouting density and sprout length dose-dependently. siRNA-mediated knockdown of the integrin β1-subunit suppressed LEC invasion and also inhibited VEGF receptor (VEGFR)3 and ERK activation. Furthermore, exposing LECs to the inflammatory mediator lipopolysaccharide (LPS) inhibited sprouting. This optimized model for LEC invasion includes S1P, VEGF-C, and fibronectin within a 3-D collagen matrix, along with VEGF-C, VEGF-A, bFGF, and HGF in the culture medium, and provides a useful tool to investigate the functional effect of various lymphangiogenic factors and inhibitors.

A novel polysaccharide from Acorus tatarinowii protects against LPS-induced neuroinflammation and neurotoxicity by inhibiting TLR4-mediated MyD88/NF-κB and PI3K/Akt signaling pathways

Our previous study has indicated that a crude polysaccharide derived from Acorus tatarinowii, AT50, remarkably improves learning and memory in scopolamine-induced amnesic mice and prevents the release of inflammatory mediators. To further explore the bioactive constituents of AT50, a novel polysaccharide (ATP50-3) was purified, and its anti-neuroinflammatory effects and underlying mechanisms were investigated. ATP50-3 significantly reduced abnormal elevation of inflammatory mediators in lipopolysaccharide (LPS)-induced proinflammatory BV2 cells in vitro and inhibited the activation of nuclear factor kappa B (NF-κB). Moreover, ATP50-3 down-regulated LPS-induced protein levels of Toll-like receptor 4 (TLR4), myeloid differentiation primary response protein (MyD88), p-PI3K (phosphoinositide 3-kinase), and p-Akt (protein kinase B). Further experiments demonstrated that TAK242 (a TLR4 inhibitor) and LY294002 (a PI3K inhibitor) remarkably augmented ATP50-3's down-regulation on LPS-induced proinflammatory mediators. Importantly, ATP50-3 provided neuroprotection against neuroinflammation-induced neurotoxicity in primary cortical and hippocampal neurons by mitigating overproduction of reactive oxygen species and damage to the mitochondrial membrane potential (MMP). Taken together, our findings suggest that ATP50-3 exerts anti-neuroinflammatory and neuroprotective effects through modulation of TLR4-mediated MyD88/NF-κB and PI3K/Akt signaling pathways.

Anti-inflammatory effect of aerial bulblets of Dioscorea japonica Thunb extract through inhibition of NF-κB and MAPK signalling pathway in RAW 264.7.

Yam (Dioscorea japonica Thunb) is a well-known health food in Korea and is widely distributed in the temperate and tropical regions. Although various medical effects of yam have been demonstrated, there is little current knowledge on the efficacy of Youngyeoja (YYJ; the aerial bulblets of the yam plant), their physiological effects, and their mechanism of action. To investigate the anti-inflammatory effects of YYJ, we examined the level of inflammatory mediators in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells treated with YYJ extract. Nitric oxide (NO) and prostaglandin E2 (PGE2) levels were determined using enzyme-linked immunosorbent assays. Expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were evaluated using real-time polymerase chain reaction and western blotting. In addition, activation of nuclear factor-kappaB (NF-κB) and mitogen-activated protein kinase (MAPK) was detected using western blotting. Treatment of macrophages with LPS markedly induced the production of NO and PGE2. YYJ treatment inhibited the induction of inflammatory mediators and the expression of iNOS and COX-2. More importantly, LPS-induced phosphorylation of nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor (IκB) was suppressed by treatment with YYJ, suggesting YYJ inhibited NF-κB activation. Furthermore, YYJ inhibited the LPS-induced phosphorylation of MAPKs. YYJ was shown to have a potent anti-inflammatory effect in LPS-stimulated RAW 264.7 cells, which may be attributed to its inhibitory effect on NF-κB and MAPK activation, consequently blocking the production of inflammatory factors. Therefore, these results suggest that the YYJ extracts could be used as anti-inflammatory agents.

NF‐κB activation mediates LPS‐or zymosan‐induced hypotension and inflammation reversed by BAY61‐3606, a selective Syk inhibitor, in rat models of septic and non‐septic shock

We have previously demonstrated that the activation of the spleen tyrosine kinase (Syk)/inhibitory-κB (IκB)-α/nuclear factor-κB (NF-κB) p65 signalling pathway contributes to hypotension and inflammatory response in a rat models of zymosan (ZYM)-induced non-septic shock. The purpose of this study was to further examine the possible mechanism underlying the effect of inhibition of Syk by BAY61-3606 via NF-κB activity at the level of nuclear translocation regarding the production of vasodilator and proinflammatory mediators in lipopolysaccharide (LPS) (septic)- and ZYM (non-septic)-induced shock. Administration of LPS (10mg/kg, ip) or ZYM (500mg/kg, ip) to male Wistar rats decreased mean arterial pressure and increased heart rate that was associated with an increase in the activities of cyclooxygenase and nitric oxide synthase, tumour necrosis factor-α, and interleukin-8 levels, and NF-κB activation and nuclear translocation in sera and/or cardiovascular and renal tissues. BAY61-3606 (3mg/kg, ip), the selective Syk inhibitor, given 1hour after LPS- or ZYM injection reversed all the above-mentioned effects. These results suggest that Syk contributes to the LPS- or ZYM-induced hypotension and inflammation associated with transactivation of NF-κB in septic and non-septic shock.

Effect of Inflammatory Mediators Lipopolysaccharide and Lipoteichoic Acid on Iron Metabolism of Differentiated SH-SY5Y Cells Alters in the Presence of BV-2 Microglia.

Lipopolysaccharide (LPS) and lipoteichoic acid (LTA), the Gram-negative and the Gram-positive bacterial cell wall components are important mediators of neuroinflammation in sepsis. LPS and LTA are potent activators of microglial cells which induce the production of various pro-inflammatory cytokines. It has been demonstrated that disturbance of iron homeostasis of the brain is one of the underlying causes of neuronal cell death but the mechanisms contributing to this process are still questionable. In the present study, we established monocultures of differentiated SH-SY5Y cells and co-cultures of differentiated SH-SY5Y cells and BV-2 microglia as neuronal model systems to selectively examine the effect of inflammatory mediators LPS and LTA on iron homeostasis of SH-SY5Y cells both in mono- and co-cultures. We monitored the IL-6 and TNFα secretions of the treated cells and determined the mRNA and protein levels of iron importers (transferrin receptor-1 and divalent metal transporter-1), and iron storing genes (ferritin heavy chain and mitochondrial ferritin). Moreover, we examined the relation between hepcidin secretion and intracellular iron content. Our data revealed that LPS and LTA triggered distinct responses in SH-SY5Y cells by differently changing the expressions of iron uptake, as well as cytosolic and mitochondrial iron storage proteins. Moreover, they increased the total iron contents of the cells but at different rates. The presence of BV-2 microglial cells influenced the reactions of SH-SY5Y cells on both LPS and LTA treatments: iron uptake and iron storage, as well as the neuronal cytokine production have been modulated. Our results demonstrate that BV-2 cells alter the iron metabolism of SH-SY5Y cells, they contribute to the iron accumulation of SH-SY5Y cells by manipulating the effects of LTA and LPS proving that microglia are important regulators of neuronal iron metabolism at neuroinflammation.

Peucedani Japonici Radix ameliorates lipopolysaccharide-induced neuroinflammation by regulating microglial responses

Neuroinflammation is an inflammatory process within the central nervous system that is mediated by microglial activation, which releases pro-inflammatory mediators leading to neurodegeneration. In this study, we investigated the effects of Peucedani Japonici Radix (PJR), a medicinal herb traditionally used in East Asia to treat neuroinflammation both in vitro and in vivo. First, we examined the effects of PJR on pro-inflammatory mediators in lipopolysaccharide (LPS)-stimulated BV-2 microglial cells. The results showed that PJR suppressed the LPS-induced increase of several inflammatory factors, such as nitric oxide, inducible nitric oxide synthase, cyclooxygenase-2, prostaglandin E2, interleukin-1β, and tumor necrosis factor-α. We also revealed that PJR inhibited the nuclear factor kappa B (NF-κB) pathway, which is the upstream modulator of inflammatory processes. Furthermore, to confirm the regulatory effects of PJR on microglia in vivo, we measured the number of ionized calcium-binding adapter molecule 1-positive cells in mouse brains and found that PJR treatment reduced microglial activation. Taken together, these results suggest that PJR inhibits microglia-mediated neuroinflammation through the modulation of NF-κB signaling and has the therapeutic potential to prevent inflammation-related neurodegenerative diseases.

Fucosterol inhibits the cholinesterase activities and reduces the release of pro-inflammatory mediators in lipopolysaccharide and amyloid-induced microglial cells

According to the cholinergic hypothesis, memory impairment in patients with Alzheimer’s disease (AD) is associated with the deficit of cholinergic function in the brain. In addition, microglial activation plays an important role in AD by producing pro-inflammatory cytokines, nitric oxide (NO), and prostaglandin E2 (PGE2). It was noted that lipopolysaccharide (LPS) and β-amyloid (Aβ) induced microglial activation leading to neuroinflammation and ultimately neuronal cell death. Fucosterol, a plant sterol found in brown algae, has been reported to exhibit several bioactivities. This study aimed to investigate the anti-cholinesterase activities of fucosterol and its effects on the release of pro-inflammatory mediators by LPS- and Aβ-induced microglial cells. Cholinesterase inhibition was determined using the modified Ellman colorimetric method. Expression of pro-inflammatory mediators was determined using RT-PCR and ELISA. The NO content was determined using the Griess test. Fucosterol exhibited dose-dependent inhibitory activities against both acetylcholinesterase and butyrylcholinesterase. It significantly inhibited the production of cytokines, namely interleukins (IL-6, IL-1β), tumor necrosis factor-α (TNF-α), NO, and PGE2 in LPS- or Aβ-induced microglial cells. Fucosterol provided protective effects against Aβ-mediated neuroinflammation by inhibiting the production of pro-inflammatory mediators. These findings provided insights into the development of fucosterol as a potential drug candidate for AD, a multifactorial neurodegenerative disorder.

Anti-inflammatory effect and mechanism of action of Lindera erythrocarpa essential oil in lipopolysaccharide-stimulated RAW264.7 cells.

The aim of this study was to investigate the chemical constituents of Lindera erythrocarpa essential oil (LEO) by gas chromatography-mass spectrometry and evaluate their inhibitory effect on the expression of pro-inflammatory mediators in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Fifteen compounds, accounting for 63.7 % of the composition of LEO, were identified. The main compounds were nerolidol (18.73 %), caryophyllene (14.41 %), α-humulene (7.73 %), germacrene-D (4.82 %), and α-pinene (4.47 %). LEO significantly inhibited the expression of inducible nitric oxide (NO) synthase and cyclooxygenase-2, and subsequent production of NO and prostaglandin E2. In addition, it reduced the release of pro-inflammatory cytokines in LPS-activated RAW264.7 cells. The molecular mechanism underlying the effect of LEO was associated with inhibition of the phosphorylation of mitogen-activated protein kinase (MAPK). Furthermore, LEO inhibited LPS-induced phosphorylation and degradation of inhibitor of kappa B-α, which is required for the activation of the p50 and p65 nuclear factor (NF)-κB subunits in RAW264.7 cells. Taken together, these data suggest that LEO exerted its anti-inflammatory effect by downregulating LPS-induced production of pro-inflammatory mediators through the inhibition of NF-κB and MAPK signaling in RAW264.7 cells.