Neuroinflammation In BV2 Microglial Cells Research Articles

Malaysian brown macroalga Padina australis mitigates lipopolysaccharide-stimulated neuroinflammation in BV2 microglial cells.

Neuroinflammation and microglial activation are pathological features in central nervous system disorders. Excess levels of reactive oxygen species (ROS) and pro-inflammatory cytokines have been implicated in exacerbation of neuronal damage during chronic activation of microglial cells. Padina australis, a brown macroalga, has been demonstrated to have various pharmacological properties such as anti-neuroinflammatory activity. However, the underlying mechanism mediating the anti-neuroinflammatory potential of P. australis remains poorly understood. We explored the use of Malaysian P. australis in attenuating lipopolysaccharide (LPS)-stimulated neuroinflammation in BV2 microglial cells. Fresh specimens of P. australis were freeze-dried and subjected to ethanol extraction. The ethanol extract (PAEE) was evaluated for its protective effects against 1 µg/ml LPS-stimulated neuroinflammation in BV2 microglial cells. LPS reduced the viability of BV2 microglia cells and increased the levels of nitric oxide (NO), prostaglandin E2 (PGE2), intracellular reactive oxygen species (ROS), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6). However, the neuroinflammatory response was reversed by 0.5-2.0 mg/ml PAEE in a dose-dependent manner. Analysis of liquid chromatography-mass spectrometry (LC-MS) of PAEE subfractions revealed five compounds; methyl α-eleostearate, ethyl α-eleostearate, niacinamide, stearamide, and linoleic acid. The protective effects of PAEE against LPS-stimulated neuroinflammation in BV2 microglial cells were found to be mediated by the suppression of excess levels of intracellular ROS and pro-inflammatory mediators and cytokines, denoting the protective role of P. australis in combating continuous neuroinflammation. Our findings support the use of P. australis as a possible therapeutic for neuroinflammatory and neurodegenerative diseases.

The therapeutic mechanism of Shenyuan Gan in lipopolysaccharide-induced neuroinflammation in BV2 microglial cells

ObjectiveTo study the therapeutic effects of Shenyuan Gan (参远苷, SYG) on the inflammatory response in BV2 microglial cells induced by lipopolysaccharide (LPS). MethodsThe cytotoxicity of SYG to BV2 microglial cells was evaluated using a Cell Counting Kit-8 (CCK-8) assay, and the effect of SYG concentrations on LPS-induced BV2 microglial cells was studied. The morphological changes were observed using an optical microscope. The nitric oxide (NO) concentration in cell culture supernatant was determined using Griess reagent. The expression of cytokines and inflammatory mediators were also measured by an enzyme-linked immunosorbent assay (ELISA). Western blot analysis was used to determine the levels of inducible NO synthase (iNOS), nuclear factor-kappa B (NF-κB) p65, alpha inhibitor of NF-κB (IκB-α), phosphorylation-IκB-α (p-IκB-α), NOD-like receptor 3 (NLRP3), and caspase-1 expression. Moreover, the expression of iNOS, NLRP3, and ionized calcium binding adapter molecule 1 (Iba1) was also observed using immunofluorescent staining. ResultsSYG had a low cytotoxic effect on BV2 microglial cells and could significantly decr-ease LPS-induced morphological changes of BV2 microglial cells (P < 0.05). ELISA results showed that SYG significantly inhibited the LPS-induced increase in interleukin (IL)-1β and IL-6 in BV2 microglia cells (P < 0.05), and Western blot analysis showed that the phosphorylation levels of iNOS, NF-κB p65, and IκB-α as well as NLRP3 and caspase-1 expression were also significantly decreased, and IκB-α expression was increased after SYG treatment (P < 0.05, compared with the LPS-treated group). The immunofluorescence results were consistent with the Western blot results, and Iba1 staining indicated that the cell morphology tended to be resting. These results indicate that SYG has a certain inhibitory effect on LPS-induced inflammation in BV2 microglial cells. ConclusionSYG can inhibit LPS-induced release of inflammatory factors in BV2 microglial cells by affecting the phosphorylation levels of NF-κB p65 and IκB-α. SYG is a valuable candidate for treating neuroinflammation-related diseases.

Cognitive enhancement and neuroprotective effects of OABL, a sesquiterpene lactone in 5xFAD Alzheimer's disease mice model

Alzheimer's disease (AD) is a neurodegenerative disease in which oxidative stress and neuroinflammation were demonstrated to be associated with neuronal loss and cognitive deficits. However, there are still no specific treatments that can prevent the progression of AD. In this study, a screening of anti-inflammatory hits from 4207 natural compounds of two different molecular libraries indicated 1,6-O,O-diacetylbritannilactone (OABL), a 1,10-seco-eudesmane sesquiterpene lactone isolated from the herb Inula britannica L., exhibited strong anti-inflammatory activity in vitro as well as favorable BBB penetration property. OABL reduced LPS-induced neuroinflammation in BV-2 microglial cells as assessed by effects on the levels of inflammatory mediators including NO, PGE2, TNF-α, iNOS, and COX-2, as well as the translocation of NF-κB. Besides, OABL also exhibited pronounced neuroprotective effects against oxytosis and ferroptosis in the rat pheochromocytoma PC12 cell line. For in vivo research, OABL (20 mg/kg B.W., i.p.) for 21 d attenuated the impairments in cognitive function observed in 6-month-old 5xFAD mice, as assessed with the Morris water maze test. OABL restored neuronal damage and postsynaptic density protein 95 (PSD95) expression in the hippocampus. OABL also significantly reduced the accumulation of amyloid plaques, the Aβ expression, the phosphorylation of Tau protein, and the expression of BACE1 in AD mice brain. In addition, OABL attenuated the overactivation of microglia and astrocytes by suppressing the expressions of inflammatory cytokines, and increased glutathione (GSH) and reduced malondialdehyde (MDA) and super oxide dismutase (SOD) levels in the 5xFAD mice brain. In conclusion, these results highlight the beneficial effects of the natural product OABL as a novel treatment with potential application for drug discovery in AD due to its pharmacological profile.

The Anti-diabetic Drug Gliquidone Modulates Lipopolysaccharide-Mediated Microglial Neuroinflammatory Responses by Inhibiting the NLRP3 Inflammasome.

The sulfonylurea drug gliquidone is FDA approved for the treatment of type 2 diabetes. Binding of gliquidone to ATP-sensitive potassium channels (SUR1, Kir6 subunit) in pancreatic β-cells increases insulin release to regulate blood glucose levels. Diabetes has been associated with increased levels of neuroinflammation, and therefore the potential effects of gliquidone on micro- and astroglial neuroinflammatory responses in the brain are of interest. Here, we found that gliquidone suppressed LPS-mediated microgliosis, microglial hypertrophy, and proinflammatory cytokine COX-2 and IL-6 levels in wild-type mice, with smaller effects on astrogliosis. Importantly, gliquidone downregulated the LPS-induced microglial NLRP3 inflammasome and peripheral inflammation in wild-type mice. An investigation of the molecular mechanism of the effects of gliquidone on LPS-stimulated proinflammatory responses showed that in BV2 microglial cells, gliquidone significantly decreased LPS-induced proinflammatory cytokine levels and inhibited ERK/STAT3/NF-κB phosphorylation by altering NLRP3 inflammasome activation. In primary astrocytes, gliquidone selectively affected LPS-mediated proinflammatory cytokine expression and decreased STAT3/NF-κB signaling in an NLRP3-independent manner. These results indicate that gliquidone differentially modulates LPS-induced microglial and astroglial neuroinflammation in BV2 microglial cells, primary astrocytes, and a model of neuroinflammatory disease.

HACE1 negatively regulates neuroinflammation through ubiquitylating and degrading Rac1 in Parkinson's disease models.

Neuroinflammation plays an important role in neurodegenerative diseases, such as Parkinson's disease (PD) and Alzheimer's disease. HACE1 (HECT domain and Ankyrin repeat Containing E3 ubiquitin-protein ligase 1) is a tumor suppressor. Recent evidence suggests that HACE1 may be involved in oxidative stress responses. Due to the critical role of ROS in neuroinflammation, we speculated that HACE1 might participate in neuroinflammation and related neurodegenerative diseases, such as PD. In this study, we investigated the role of HACE1 in neuroinflammation of PD models. We showed that HACE1 knockdown exacerbated LPS-induced neuroinflammation in BV2 microglial cells in vitro through suppressing ubiquitination and degradation of activated Rac1, an NADPH oxidase subunit. Furthermore, we showed that HACE1 exerted vital neuronal protection through increasing Rac1 activity and stability in LPS-treated SH-SY5Y cells, as HACE1 knockdown leading to lower tolerance to LPS challenge. In MPTP-induced acute PD mouse model, HACE1 knockdown exacerbated motor deficits by activating Rac1. Finally, mutant α-synuclein (A53T)-overexpressing mice, a chronic PD mouse model, exhibited age-dependent reduction of HACE1 levels in the midbrain and striatum, implicating that HACE1 participated in PD pathological progression. This study for the first time demonstrates that HACE1 is a negative regulator of neuroinflammation and involved in the PD pathogenesis by regulating Rac1 activity. The data support HACE1 as a potential target for PD and other neurodegenerative diseases.

Nilotinib inhibits microglia-mediated neuroinflammation to protect against dopaminergic neuronal death in Parkinson’s disease models

Microglia-mediated neuroinflammation is tightly correlated with the etiology and progression of neurodegenerative disorders, including Parkinson’s disease (PD). Nilotinib, a c-Abl inhibitor used for chronic myeloid leukemia, has been proven effective in relieving PD progression. However, whether nilotinib could affect neuroinflammation is largely unknown. In this current study, we investigated the role of nilotinib in microglia-mediated neuroinflammatory response in Parkinson’s disease. Lipopolysaccharide (LPS)-induced neuroinflammation in BV2 microglial cells and mouse brains were used as models for Parkinson’s disease. Our results demonstrated that nilotinib significantly suppressed LPS-induced neuroinflammation by reducing the production of pro-inflammatory factors including iNOS, COX-2, IL-1β, IL-6 and TNF-α in BV2 cells. Moreover, pretreatment of nilotinib attenuated the neurotoxicity of LPS-treated microglial conditioned medium to MES23.5 dopaminergic (DA) neurons. Mechanismly, nilotinib inhibited NF-κB signaling pathway and suppressed the nuclear translocation of p65 upon LPS stimulation. In LPS-injected mouse brains, nilotinib administration markedly suppressed the activation of microglia and down-regulated COX-2 as well as IL-1β expression. Most importantly, nilotinib effectively protected against microglial activation-mediated mouse DA neuronal loss. Taken together, our study suggests that nilotinib exerts anti-neuroinflammatory effect and protects DA neurons from activated microglia-induced inflammatory damage through suppressing NF-κB signaling pathway, indicating its potential application in further clinical trials.

Ganoderic Acid A Attenuates LPS-Induced Neuroinflammation in BV2 Microglia by Activating Farnesoid X Receptor

Neuroinflammation plays an important role in the onset and progression of neurodegenerative diseases. Microglia-mediated neuroinflammation have been proved to be the main reason for causing the neurodegenerative diseases. Ganoderic acid A (GAA), isolated from Ganoderma lucidum, showed anti-inflammatory effect in metabolism diseases. However, little research has been focused on the effect of GAA in neuroinflammation and the related mechanism. In the present study, lipopolysaccharide(LPS)-stimulated BV2 microglial cells were used to evaluate the anti-inflammatory capacity of GAA. Our data showed that GAA significantly suppressed LPS-induced BV2 microglial cells proliferation and activation in vitro. More strikingly, GAA promoted the conversion of BV2 microglial cells from M1 status induced by LPS to M2 status. Furthermore, GAA inhibited the pro-inflammatory cytokines release and promoted neurotrophic factor BDNF expression in LPS-induced BV2 microglial cells. Finally, we found that the expression of farnesoid-X-receptor (FXR) was prominently downregulated in LPS-stimulated BV2 microglial cells, antagonism of FXR with z-gugglesterone and FXR siRNA can reverse the effect of GAA in LPS-induced BV2 microglial cells. Taking together, our findings demonstrate that GAA can significantly inhibit LPS-induced neuroinflammation in BV2 microglial cells via activating FXR receptor.

Piperhancins A and B, Two Pairs of Antineuroinflammatory Cycloneolignane Enantiomers from Piper hancei

Two pairs of cycloneolignane enantiomers, piperhancins A and B (1 and 2, respectively), along with two enantiomeric pairs of biosynthetic related neolignanes, hancinone C (3) and piperhancin C (4), were isolated from the stems of Piper hancei. Compound 1 is an unprecedented 1',2:1,2'-dicyclo-8,3'-neolignane. Their structures and absolute configurations were elucidated by spectroscopic analyses, X-ray diffraction, and electronic circular dichroism calculations. Among all of the isolates, compounds (+)-1, (-)-1, (+)-2, (-)-2, and (+)-3 could significantly inhibit the production of nitric oxide secreted by lipopolysaccharide (LPS)-induced neuroinflammation in BV-2 microglial cells, with IC50 values of 1.1-26.3 μM. In addition, compound (-)-1 could decrease the mRNA levels of iNOS, IL-6, and TNF-α induced by LPS in BV-2 microglial cells.

Role of Militarine in PM2.5-Induced BV-2 Cell Damage.

A growing number of studies have shown that air fine particulate matter (PM2.5) pollution is closely associated with neuroinflammation in humans. Militarine, a glucosyloxybenzyl 2-isobutylmalate compound isolated from Bletilla striata, has been found to exert significant neuroprotective effects. However, the anti-inflammatory, antioxidant and antiapoptotic effects of militarine on PM2.5-stimulated BV-2 microglial cells have not been reported. This study aimed to investigate the protective effects of militarine against PM2.5-induced cytotoxicity and its mechanism in BV-2 microglial cells. Our results revealed that pretreatment with 0.31-1.25μg/mL militarine reversed the morphological changes caused by PM2.5 and decreased proinflammatory cytokine generation and gene expression in PM2.5-treated BV-2 cells. In particular, tumor necrosis factor-α and interleukin-6 expression was inhibited in a dose-dependent manner. Notably, militarine markedly inhibited the upregulation of Toll-like receptor 4, Toll-like receptor 2, and cyclo-oxygenase-2 expression at both the mRNA and protein levels and reduced NF-κB pathway-associated protein expression. Immunofluorescence analysis showed that militarine suppressed NF-κB activity through inhibiting p65 nuclear translocation. Our data suggested that militarine alleviated neuroinflammation in BV-2 microglial cells, possibly by inhibiting the expression of neuroinflammatory cytokines through the TLR/NF-κB signaling pathway. Additionally, militarine significantly reduced PM2.5-mediated reactive oxygen species (ROS) generation and cell apoptosis and restored the mitochondrial membrane potential (MMP; ΔΨm). Collectively, these findings demonstrate that militarine played a protective role against PM2.5-induced damage in BV-2 cells by exerting anti-inflammatory, antioxidant, and antiapoptotic effects.

Effects and mechanism of atractylone from rhizomes of Atractylodes macrocephala Koidzumi in LPS-induced neuro-inflammation in BV2 microglial cells

Effects and mechanism of atractylone from rhizomes of Atractylodes macrocephala Koidzumi in LPS-induced neuro-inflammation in BV2 microglial cells

Glabridin downregulates lipopolysaccharide-induced oxidative stress and neuroinflammation in BV-2 microglial cells via suppression of nuclear factor-κB signaling pathway

Background: Microglia initially undergoes chronic activation in response to the damages caused by stressful stimuli, such as bacterial infection and hypoxia. Inflammatory responses, as well as oxidative stress, perform crucial roles in the process of neuroinflammation, which results in brain damage. Glabridin is a natural organic compound with extensive beneficial properties such as anti-inflammatory and antioxidant properties. To the best of our knowledge, there are no studies conducted on the anti-neuroinflammatory activity of glabridin. Therefore, in this study, we aimed to investigate the potency of glabridin against the expression of lipopolysaccharide (LPS)-stimulated BV-2 cells. Materials and Methods: BV-2 cells were preincubated with glabridin followed by the LPS challenge. Subsequently, the cellular status of nitric oxide (NO), reactive oxygen species (ROS), prostaglandin E2(PGE2), and pro-inflammatory modulators (interleukin [IL]-1β and IL-6) were investigated and related signaling pathways were inspected via blotting assay. Results: Our results indicate that glabridin appreciably alleviated the LPS-induced accretion of inducible-NO synthase (iNOS), PGE2, IL-1β, and IL-6. Moreover, it noticeably allayed the NO/iNOS, PGE2/cyclooxygenase-2 protein statuses, and pro-inflammatory cytokine (tumor necrosis factor-α) on LPS-induced microglia. We also found that LPS severely increased the phosphorylation of Inhibitory kappa B kinases (IKKs), IκBα, p65, and nuclear factor (NF)-κB. Although glabridin supplementation suppressed the phosphorylation of the aforementioned molecules, LPS remarkable caused the nuclear interchange of NF-κBp65. Conclusion: Glabridin alleviates LPS-induced neuroinflammation in BV-2 cells by suppressing the accumulation of ROS and cell death and by inhibiting the pro-inflammatory responses via NF-κB-dependent mechanisms. According to our results, glabridin may be beneficial in neuroinflammation-related neurodegenerative disorders.

Neuroprotective effects of isoflurane against lipopolysaccharide-induced neuroinflammation in BV2 microglial cells by regulating HMGB1/TLRs pathway.

Microglia, as the first line of defence of the central nervous system (CNS), has a major role in inflammatory response. It was reported that isoflurane has a neuroprotective role in the pathological process of CNS by interfering with inflammatory response. While the mechanism and function of isoflurane in microglia-mediated inflammation are still not clearly articulated. In our study, the inflammation model was established by the activation of lipopolysaccharide (LPS) in BV2 cells in vitro. The results demonstrated that isoflurane inhibited the release of nitric oxide (NO) and enhanced the survival of BV2 cells, meanwhile, isoflurane reduced the levels of inflammatory factors and downregulated the expressions of inflammation-related genes and proteins in LPS-mediated BV2 cells. Furthermore, we demonstrated that overexpression of high-mobility group box 1 protein (HMGB1) could reverse the reduction in NO concentration, enhancement of cell BV2 viability and inhibition of inflammatory response, which were mediated by isoflurane in LPS-induced BV2 cells. Therefore, we suggested that isoflurane inhibits the activation of LPS-induced neuro microglia and reduces the release of inflammatory factors by regulating HMGB1, suggesting that isoflurane might play a protective role in LPS-induced neuroinflammation through the HMGB1 pathway.

The novel DYRK1A inhibitor KD03 alters neuroinflammation in BV2 microglial cells, wild-type, and Alzheimer's transgenic mice

The novel DYRK1A inhibitor KD03 alters neuroinflammation in BV2 microglial cells, wild-type, and Alzheimer's transgenic mice

Synthesis of gold and silver nanoparticles using flavonoid quercetin and their effects on lipopolysaccharide induced inflammatory response in microglial cells.

Quercetin is a plant origin phytochemical with several pharmaceutical activities such as antioxidant, immunomodulatory, and anti-inflammatory effects. However, consumption of quercetin is limited due to its low aqueous solubility and poor bioavailability. The aim of the present study was to synthesize silver and gold nanoparticles of quercetin with a view to improve its aqueous phase solubility and investigate the effects on LPS-induced neuroinflammation in BV-2 microglial cells. The average size of silver and gold-quercetin nanoparticles was 53 and 27nm, respectively. Absorption peaks in the UV-Vis spectra were observed at 555 and 405nm for gold and silver-quercetin nanoparticles, respectively. The particle size and mapping of silver and gold-quercetin nanoparticles were also determined using a STEM detector. The inflammatory stimulation of the BV-2 cells with LPS caused an elevated release of proinflammatory prostaglandin, E2, nitric oxide (NO), upregulated cyclooxygenase-2, inducible NO synthase mRNA, and protein levels, which were markedly inhibited by the pretreatment with gold-quercetin nanoparticles (highly soluble in water) without causing any cytotoxic effects. The findings of the present study suggest that the potential of gold-quercetin nanoparticles are much better than quercetin and that gold-quercetin nanoparticles might provide protection against inflammatory neurodegenerative disease via suppression of acute microglial activation.

Cystatin F involvement in adenosine A2A receptor-mediated neuroinflammation in BV2 microglial cells

Our previous studies have shown adenosine A2A R activation markedly promotes the expression of cystatin F (CF) and exacerbates the white matter lesions induced by hypoxic brain injuries. Thus, we hypothesized that CF was probably involved in neuroinflammation of activated microglia induced by A2A R activation. We transfected the BV2 cells with a CF shRNA vector and examined the production of pro-inflammatory cytokines in hypoxic-BV2 cells in which A2A R was activated or inactivated to confirm this hypothesis. Additionally, we also investigated the probable signaling pathways involved in modulation of A2A R activation on CF expression in hypoxia-activated BV2 cells. Activation of A2A R promoted CF expression, which was significantly increased after the low glucose and hypoxia treatments in BV2 cells. CF gene knockdown markedly inhibited the increase in the expression of pro-inflammatory cytokines induced by A2A R activation in hypoxic-BV2 cells. Furthermore, the increased expression of the CF induced by A2A R activation was remarkably inhibited in hypoxic-BV2 cells administrated with the PKA inhibitor H-89 and the PKC inhibitor staurosporine. Hence, these results indicate that hypoxia BV2 cells highly express CF, which is involved in A2A R activation-mediated neuroinflammation via the PKA/CREB and PKC/CREB or ERK1/2 signaling pathways.

Magnesium Lithospermate B Suppresses Lipopolysaccharide-Induced Neuroinflammation in BV2 Microglial Cells and Attenuates Neurodegeneration in Lipopolysaccharide-Injected Mice.

Chronic inflammation in the brain plays a critical role in major neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and multiple sclerosis (MS). Microglia, the resident macrophages and intrinsic components of the central nervous system (CNS), appear to be the main effectors in this pathological process. Magnesium lithospermate B (MLB) is one of the major bioactive components of Radix Salviae miltiorrhizae, which has been documented to protect neurons against multiple types of neuronal injury. However, its functions on microglia and the related neuroinflammation remain unknown. In the present study, BV2 microglial cells were used to assess the anti-neuroinflammatory capacity of MLB. Our data show that treatment with MLB could not only suppress lipopolysaccharide (LPS)-induced proliferation and morphological changes, but also interfere with cell cycle progression in BV2 cells. More strikingly, it attenuated the production of the inflammatory mediator nitric oxide (NO) and a panel of pro-inflammatory cytokine in LPS-stimulated BV2 cells, including tumor necrosis factor-α (TNF-α), interleukin (IL)-1α, IL-1β, and IL-6, and also promoted a phenotypic switch from the M1 to the M2 phenotype. Additionally, an in vivo study showed that the administration of MLB could ameliorate lipopolysaccharide-induced neurodegeneration and microglial activation in the hippocampus of adult mice. Mechanistically, MLB blocked the activation of the NF-κB pathway upon LPS stimulation, indicating that the effects of MLB on microglia may be mediated by the NK-κB pathway. These results suggest the therapeutic potential of MLB as a novel anti-inflammatory and microglia-modulating drug for neurodegenerative diseases.

Trans-caryophyllene inhibits amyloid β (Aβ) oligomer-induced neuroinflammation in BV-2 microglial cells

Amyloid β (Aβ) is the major component of senile plaques (SP) in the brains of Alzheimer's disease (AD) patients, and serves as an inflammatory stimulus for microglia. Trans-caryophyllene (TC), a major component in the essential oils derived from various species of medicinal plants, has displayed its neuro-protective effects in previous studies. However, whether TC has a protective role in AD remains unknown. In this study, the effects of TC on Aβ1–42-induced neuro-inflammation were investigated. We found that TC reduced the release of LDH in BV-2 microglial cells treated with Aβ1–42. In addition, pretreatment of BV2 microglia with TC at concentrations of 10, 25, and 50μM prior to Aβ stimulation led to significant inhibition of nitric oxide (NO) and prostaglandin E2 (PGE2) production, expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and secretion of pro-inflammatory cytokines. Notably, our results indicate that TC remarkably attenuated Aβ1–42-activated overexpression of toll-like receptor 4 (TLR4). We further demonstrated that TC markedly reversed Aβ1–42-induced phosphorylation and degradation of IκBα, nuclear translocation of p65, and NF-κB transcriptional activity. These findings suggest that TC may have therapeutic potential for the treatment of AD.

Ramulus Cinnamomi extract attenuates neuroinflammatory responses via downregulating TLR4/MyD88 signaling pathway in BV2 cells.

Ramulus Cinnamomi (RC), a traditional Chinese herb, has been used to attenuate inflammatory responses. The purpose of this study was to investigate the effect of RC extract on lipopolysaccharide (LPS)-induced neuroinflammation in BV2 microglial cells and the underlying mechanisms involved. BV2 cells were incubated with normal medium (control group), LPS, LPS plus 30 μg/mL RC extract, or LPS plus 100 μg/mL RC extract. The BV2 cell morphology was observed under an optical microscope and cell viability was detected by MTT assay. Nitric oxide level in BV2 cells was detected using Griess regents, and the levels of interleukin-6, interleukin-1β, and tumor necrosis factor α in BV2 cells were determined by ELISA. The expression levels of cyclooxygenase-2, Toll-like receptor 4 and myeloid differentiation factor 88 proteins were detected by western blot assay. Compared with the LPS group, both 30 and 100 μg/mL RC extract had no significant effect on the viability of BV2 cells. The levels of nitric oxide, interleukin-6, interleukin-1β and tumor necrosis factor α in BV2 cells were all significantly increased after LPS induction, and the levels were significantly reversed after treatment with 30 and 100 μg/mL RC extract. Furthermore, RC extract significantly inhibited the protein expression levels of cyclooxygenase-2, Toll-like receptor 4 and myeloid differentiation factor 88 in LPS-induced BV2 cells. Our findings suggest that RC extract alleviates neuroinflammation by downregulating the TLR4/MyD88 signaling pathway.

Effects of ginsenoside Re on LPS-induced inflammatory mediators in BV2 microglial cells

BackgroundMicroglial activation plays an important role in neurodegenerative diseases by producing several pro-inflammatory enzymes and pro-inflammatory cytokines. Lipopolysaccharide (LPS)-induced inflammation leads to the activation of microglial cells in the central nervous system (CNS) and is associated with the pathological mechanisms of neurodegenerative diseases, including PD, AD, and ALS. Ginseng is a natural antioxidant used in herbal medicine and contains ginsenosides (Rb1, Rg1, Rg3, Re, and Rd), which have anti-neoplastic and anti-stress properties.This study demonstrates the involvement of the anti-inflammatory signaling pathway, ginsenoside-Re (G-Re), which is one of the ginsenosides mediated by LPS-induced neuroinflammation in BV2 microglial cells.MethodsBV2 microglial cells were pretreated with 2 μg/ml G-Re and stimulated with 1 μg/ml LPS to induce neuroinflammation. To investigate the effect of G-Re on LPS-induced cell signaling, we performed western blotting and immunofluorescence using specific antibodies, such as phospho-p38, COX2, and iNOS.ResultsPretreatment with 2 μg/ml G-Re was neuroprotective against 1 μg/ml LPS-treated microglial cells. The neuroprotective events induced by G-Re treatment in neuroinflammation occurred via the phospho-p38, iNOS, and COX2 signaling pathways in BV2 cells.ConclusionTaken together, we suggest that G-Re exerts a beneficial effect on neuroinflammatory events in neurodegenerative diseases.

Kaempferol acts through mitogen‐activated protein kinases and protein kinase B/AKT to elicit protection in a model of neuroinflammation in BV2 microglial cells

Kaempferol, a dietary flavonoid and phyto-oestrogen, is known to have anti-inflammatory properties. Microglial activation has been implicated in various neurodegenerative diseases. Anti-inflammatory effects of kaempferol and the underlying mechanisms were investigated by using LPS-stimulated microglial BV2 cells. Cell viability was measured using MTT and neutral red assays. elisa, Western blot, immunocytochemistry and electrophoretic mobility-shift assay were used to analyse NO, PGE(2) , TNF-α and IL-1β production, inducible NOS (iNOS), COX-2 expression and the involvement of signalling pathways such as toll-like receptor-4 (TLR4), MAPK cascades, PKB (AKT) and NF-κB. Accumulation of reaction oxygen species (ROS) was measured by nitroblue tetrazolium and 2'7'-dichlorofluorescein diacetate assay. Matrix metalloproteinase activity was investigated by zymography and immunoblot assay. Phagocytotic activity was assessed by use of latex beads. Kaempferol significantly attenuated LPS-induced NO, PGE(2) , TNF-α, IL-1β and ROS production and phagocytosis in a concentration-dependent manner. Kaempferol suppressed the expression of iNOS, COX-2, MMP-3 and blocked the TLR4 activation. Moreover, kaempferol inhibited LPS-induced NF-κB activation and p38 MAPK, JNK and AKT phosphorylation. Kaempferol was able to reduce LPS-induced inflammatory mediators through the down-regulation of TLR4, NF-κB, p38 MAPK, JNK and AKT suggesting that kaempferol has therapeutic potential for the treatment of neuroinflammatory diseases.