Pentobarbital may protect against neurogenic inflammation after surgery via inhibition of substance P release from peripheral nerves of rats.

The inflammatory response related to surgery is considered surgical inflammation. Most anesthetic agents directly or indirectly suppress the immune response. However, the intravenous anesthetics pentobarbital and ketamine were reported to inhibit the lipopolysaccharide-induced inflammatory response such as cytokines formation. Neurogenic inflammation is inflammation originating from the local release of inflammatory mediators, such as substance P (SP), by primary afferent neurons after noxious stimuli like surgery. Thus, in this study, we examined whether pentobarbital and ketamine suppress SP release from cultured dorsal root ganglion (DRG) neurons. DRG cells were dissected from male Wistar rats. Released SP was measured by radioimmunoassay. We demonstrated that higher concentrations of pentobarbital (100-1,000 µM) significantly inhibited capsaicin (100 nM)-induced, but not high K+ (50 mM)-induced, SP release from DRG cells, although a high concentration of ketamine (1 mM) did not. This study revealed that pentobarbital functions between the activation of vanilloid receptor subtype 1 (TRPV1) receptors, to which capsaicin selectively binds, and the opening of voltage-operated Ca2+ channels (VOCC) in the nerve endings. Therefore, the anti-inflammatory action of pentobarbital is mediated through different mechanisms than those of ketamine. Thus, the inhibitory effect of pentobarbital on SP release from peripheral terminals may protect against neurogenic inflammation after surgery.

Inhibition of neuroinflammation by MIF inhibitor 3-({[4-(4-methoxyphenyl)-6-methyl-2-pyrimidinyl]thio}1methyl)benzoic acid (Z-312).

Microglial overactivation-mediated neuroinflammation contributes greatly to the pathogenesis of neurodegenerative diseases, such as Parkinson's disease. Macrophage migration inhibitory factor (MIF) is a pleiotropic proinflammatory cytokine that is involved in the pathophysiology of various inflammatory diseases by inducing various proinflammatory cytokines. Compound 3-({[4-(4-methoxyphenyl)-6-methyl-2-pyrimidinyl]thio}methyl)benzoic acid (Z-312) is a novel small -molecule inhibitor of MIF tautomeric activity. In this study, we investigated the anti-inflammatory effects of Z-312 on liposaccharide (LPS)-induced neuroinflammation in vitro and in vivo. The results showed that Z-312 significantly decreased the production of nitric oxide (NO), interleukin (IL)-1ß, tumor necrosis factor (TNF)-α and IL-6 in LPS-stimulated microglial cells. Mechanistically, nuclear translocation of the p65 subunit of nuclear factor (NF)-κB, degradation and phosphorylation of IκBα, NF-κB transcriptional activity and phosphorylation of p38 mitogen-activated protein kinase (MAPK) and JNK were markedly attenuated by pretreatment with Z-312 in BV-2 microglial cells. In addition, Z-312 suppressed the neurotoxic effects of cell culture medium of LPS-activated BV-2 microglia on cocultured mouse HT22 neuroblastoma cells. An in vivo study demonstrated that Z-312 markedly ameliorated microglial activation and subsequent DA neuron loss in an LPS-induced Parkinson's disease (PD) mouse model. These results suggest that MIF inhibitor Z-312 may be a promising neuroprotective agent for the treatment of neuroinflammation-mediated neurological diseases.

Efficacy of active compounds of Chanqin granules on airway neurogenic inflammation induced by PM2.5 in vivo.

OBJECTIVE: To investigate the efficacy of active compounds of Chanqin (CQ) granules on PM2.5-induced airway neurogenic inflammation in vivo, and to elucidate the underlying mechanisms of action. METHODS: The Traditional Chinese Medicine systems pharmacology (TCMSP) database was searched, and the results were combined with oral bioavailability and drug analysis to identify the compounds in CQ granules. The pharmacophore modeling approach was used to predict the compound targets, and the diseases corresponding to the targets were obtained by searching the therapeutic target database (TTD), pharmacogenomics knowledgebase (PharmGKB) and DrugBank databases. Cytoscape software was used to construct the network pharmacological charts for Component-Target and Target-Disease interactions of the CQ granules. Then, the mechanisms of action and effectiveness of CQ granules for the treatment of PM2.5-induced airway neurogenic inflammation were analyzed. RESULTS: A total of 195 compounds and 171 targets were obtained from the analyses. A total of 569 corresponding diseases were identified for these targets. Component-target and target-disease networks were constructed. The possible mechanisms and effective components in CQ granules for treating airway neurogenic inflammation were analyzed. Quercetin, kaempferol and isorhamnetin, beta-sitosterol and sitosterol, which are typically found in the formulation, have extensive pharmacological activities, including anti-inflammatory, antioxidant and antiviral actions and neuroprotective properties. Among these targets, androgen receptor, estrogen receptor, prostaglandin G/H synthase 2, and inducible nitric oxide synthase play important pathological roles, including the induction of neurogenic inflammation. CQ granules may have therapeutic effectiveness for numerous diseases in addition to respiratory diseases, including neoplasms, digestive system diseases, cardiovascular diseases, respiratory tract diseases and nervous system diseases. In vivo, CQ granules are effective in treating pulmonary inflammation and downregulate neuropeptides in the bronchoalveolar lavage fluid after PM2.5 exposure. CQ granules significantly decreased the levels of neurokinin A, neurokinin B and calcitonin gene-related peptide in the lung and dorsal root ganglia. CQ also significantly suppressed the upregulation of p-extracellular regulated protein kinase 1/2 and p-methyl ethyl ketone 1/2 induced by PM2.5 exposure. CONCLUSION: CQ granules have potential for the treatment of neurogenic inflammation induced by PM2.5 in vivo, and the mechanism might involve downregulation of neuropeptides in the BALF, lung and dorsal root ganglia.

Shikonin ameliorates D-galactose-induced oxidative stress and cognitive impairment in mice via the MAPK and nuclear factor-κB signaling pathway.

Oxidative stress acts as the major causative factor for various age-associated neurodegenerative diseases, triggering cognitive and memory impairments. In the present study, the underlying neuroprotective mechanism governing how shikonin acts against D-galactose (D-gal)-induced memory impairment, neuroinflammation and neuron damage was examined. The results revealed that chronic administration of D-gal [150 mg/kg intraperitoneally (i.p.)] in mice caused cognitive and memory impairments, as determined by Morris water-maze test. Shikonin treatment, however, alleviated D-gal-induced memory impairment and reversed the D-gal-induced neural damage and apoptosis. Furthermore, western blotting and the results of morphological analysis revealed that shikonin treatments markedly reduced D-gal induced neuroinflammation through inhibition of astrocytosis as determined by glial fibrillary acidic protein (GFAP) detection, and downregulating other inflammatory mediators, including tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), and IL-6. Moreover, shikonin treatment led to inhibition of the activation of nuclear factor-κB (NF-κB) and the phosphorylation of mitogen-activated protein kinases (MAPKs), preventing neurodegeneration. Hence, taken together, the results of the present study suggested that shikonin attenuated D-gal-induced memory impairment, neuroinflammation and neurodegeneration, possibly via the NF-κB/mitogen-activated protein kinase (MAPK) pathway. Our data suggest that shikonin could be a promising, endogenous and compatible antioxidant candidate for age-associated neurodegenerative diseases, including Alzheimer's disease.

CSB6B prevents ß-amyloid-associated neuroinflammation and cognitive impairments via inhibiting NF-κB and NLRP3 in microglia cells.

Pathological ß-amyloid (Aß)-induced microglial activation could cause chronic neuroinflammation in the brain of Alzheimer's disease (AD) patients, and has been considered as one of the main pathological events of this disease. Chicago sky blue 6B (CSB6B), a pigment used in biochemical staining, has been reported to produce analgesic effects in neuroinflammatory-associated pain models. We have previously found that CSB6B could directly inhibit Aß aggregation and prevent Aß toxicity in neurons. However, it remains unclear whether this compound could prevent Aß-induced neuroinflammation and impairments of learning and memory in the AD models. In this study, CSB6B was found to effectively inhibit the production of pro-inflammatory cytokines, including tumor necrosis factor-α and interleukin-1ß, without affecting cell viability in BV2 microglia cells stimulated by Aß oligomer and lipopolysaccharide. Moreover, CSB6B significantly reduced mRNA expression of inducible nitric oxide synthase and increased mRNA expression of arginase-1, suggesting that CSB6B might promote the polarization of BV2 cells into M2 phenotype. In Aß oligomer-treated mice, hippocampal injection of CSB6B prevented cognitive impairments, and attenuated pro-inflammatory cytokines production. In addition, CSB6B inhibited nuclear transcription factor-κB (NF-κB), and restrainedthe activation of NOD-like receptor pyrin domain containing-3 (NLRP3) both in vitro and in vivo. According to our results, CSB6B may counteract Aß-induced cognitive impairments and neuroinflammation by inhibiting NF-κB and NLRP3. Combined with previous studies, we anticipated that CSB6B may further develop into a potential anti-AD drug with multiple functions on neurons and microglia cells, concurrently.

Effects of RO27-3225 on neurogenesis, PDGFRß+ cells and neuroinflammation after cerebral infarction.

Cerebral infarction causes severe social and economic burdens to patients due to its high morbidity and mortality rates, and the available treatments are limited. RO27-3225 is a highly selective melanocortin receptor 4 agonist that alleviates damage in many nervous system diseases, such as cerebral hemorrhage, traumatic brain injury and chronic neurodegenerative diseases. However, the effect of RO27-3225 on cerebral infarction remains unclear. In this study, we used a mouse model of transient middle cerebral artery occlusion (tMCAO) and administered RO27-3225 or saline to the mice through intraperitoneal injection. RO27-3225 increased the number of Nestin+/BrdU+ cells and doublecortin (DCX)+/BrdU+ cells in the subventricular zone (SVZ) and the number of DCX+/BrdU+ cells in the peri-infarct area on day 7 after tMCAO. Furthermore, RO27-3225 decreased the number of activated microglia (Iba1+ cells with a specific morphology) and the expression levels of Iba1, TNFα, IL6, and iNOS proteins and increased the number of PDGFRß+ cells in the peri-infarct region on day 3 after tMCAO. Finally, RO27-3225-treated mice exhibited significantly decreased infarct volumes, brain water contents, and neurological deficits after cerebral infarction. Thus, RO27-3225 can improve the outcomes following cerebral infarction, partially by regulating neurogenesis in the SVZ, PDGFRß+ cell survival and neuroinflammation in the peri-infarct zone. Our research reveals that RO27-3225 is a potential new treatment for cerebral infarction.

Baicalein attenuates the neuroinflammation in LPS-activated BV-2 microglial cells through suppression of pro-inflammatory cytokines, COX2/NF-κB expressions and regulation of metabolic abnormality.

Baicalein (5,6,7-trihydroxyflavone), isolated from the root of traditional Chinese herb Scutellaria baicalensis Georgi, has anti-inflammatory and anti-oxidative activities. This study explored the protective and modulatory mechanisms of baicalein on neuroinflammation, oxidative stress and metabolic abnormality in lipopolysaccharide (LPS)-activated BV-2 cells. Our results demonstrated that treatment with baicalein remarkably restrained the production of pro-inflammatory factors including nitric oxide (NO), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in LPS-activated BV-2 cells. Moreover, baicalein significantly inhibited reactive oxygen species (ROS) production, decreased cyclooxygenase-2 (COX-2) and nuclear factor-b (NF-κB)/p65 expression. 1H NMR metabolomics analysis revealed that 12 differential metabolites were regulated by baicalein, implicated in alanine, aspartate and glutamate metabolism, glutathione metabolism, arginine and proline metabolism, D-glutamine and D-glutamate metabolism. In conclusion, these results indicated that baicalein has protective and modulatory effects on neuroinflammation and oxidative stress in LPS-activated BV-2 cells.

Intranasal MMI-0100 Attenuates Aß1-42- and LPS-Induced Neuroinflammation and Memory Impairments via the MK2 Signaling Pathway.

Background: Accumulating evidence suggests inhibiting neuroinflammation as a potential target in therapeutic or preventive strategies for Alzheimer's disease (AD). MAPK-activated protein kinase II (MK2), downstream kinase of p38 mitogen activated protein kinase (MAPK) p38 MAPK, was unveiled as a promising option for the treatment of AD. Increasing evidence points at MK2 as involved in neuroinflammatory responses. MMI-0100, a cell-penetrating peptide inhibitor of MK2, exhibits anti-inflammatory effects and is in current clinical trials for the treatment of pulmonary fibrosis. Therefore, it is important to understand the actions of MMI-0100 in neuroinflammation. Methods: The mouse memory function was evaluated using novel object recognition (NOR) and object location recognition (OLR) tasks. Brain hippocampus tissue samples were analyzed by quantitative PCR, Western blotting, and immunostaining. Near-infrared fluorescent and confocal microscopy experiments were used to detect the brain uptake and distribution after intranasal MMI-0100 application. Results: Central MMI-0100 was able to ameliorate the memory deficit induced by Aß1-42 or LPS in novel object and location memory tasks. MMI-0100 suppressed LPS-induced activation of astrocytes and microglia, and dramatically decreased a series of pro-inflammatory cytokines such as TNF-α, IL-6, IL-1ß, COX-2, and iNOS via inhibiting phosphorylation of MK2, but not ERK, JNK, and p38 in vivo and in vitro. Importantly, one of the reasons for the failure of macromolecular protein or peptide drugs in the treatment of AD is that they cannot cross the blood-brain barrier. Our data showed that intranasal administration of MMI-0100 significantly ameliorates the memory deficit induced by Aß1-42 or LPS. Near-infrared fluorescent and confocal microscopy experiment results showed that a strong fluorescent signal, coming from mouse brains, was observed at 2 h after nasal applications of Cy7.5-MMI-0100. However, brains from control mice treated with saline or Cy7.5 alone displayed no significant signal. Conclusions: MMI-0100 attenuates Aß1-42- and LPS-induced neuroinflammation and memory impairments via the MK2 signaling pathway. Meanwhile, these data suggest that the MMI-0100/MK2 system may provide a new potential target for treatment of AD.

TRPA1 Channel as a Regulator of Neurogenic Inflammation and Pain: Structure, Function, Role in Pathophysiology, and Therapeutic Potential of Ligands.

TRPA1 is a cation channel located on the plasma membrane of many types of human and animal cells, including skin sensory neurons and epithelial cells of the intestine, lungs, urinary bladder, etc. TRPA1 is the major chemosensor that also responds to thermal and mechanical stimuli. Substances that activate TRPA1, e.g., allyl isothiocyanates (pungent components of mustard, horseradish, and wasabi), cinnamaldehyde from cinnamon, organosulfur compounds from garlic and onion, tear gas, acrolein and crotonaldehyde from cigarette smoke, etc., cause burning, mechanical and thermal hypersensitivity, cough, eye irritation, sneezing, mucus secretion, and neurogenic inflammation. An increased activity of TRPA1 leads to the emergence of chronic pruritus and allergic dermatitis and is associated with episodic pain syndrome, a hereditary disease characterized by episodes of debilitating pain triggered by stress. TRPA1 is now considered as one of the targets for developing new anti-inflammatory and analgesic drugs. This review summarizes information on the structure, function, and physiological role of this channel, as well as describes known TRPA1 ligands and their significance as therapeutic agents in the treatment of inflammation-associated pain.

Nerve sprouting and neurogenic inflammation characterize the neurogenic detrusor overactive bladder of patients no longer responsive to drug therapies.

Urothelium and Lamina Propria (LP) are considered an integrate sensory system which is able to control the detrusor activity. Complete supra-sacral spinal cord lesions cause Neurogenic Detrusor Overactivity (NDO) whose main symptoms are urgency and incontinence. NDO therapy at first consists in anti-muscarinic drugs; secondly, in intra-vesical injection of botulinum toxin. However, with time, all the patients become insensitive to the drugs and decide for cystoplastic surgery. With the aim to get deeper in both NDO and drug's efficacy lack pathogenesis, we investigated the innervation, muscular and connective changes in NDO bladders after surgery by using morphological and quantitative methodologies. Bladder innervation showed a significant global loss associated with an increase in the nerve endings located in the upper LP where a neurogenic inflammation was also present. Smooth muscle cells (SMC) anomalies and fibrosis were found in the detrusor. The increased innervation in the ULP is suggestive for a sprouting and could condition NDO evolution and drug efficacy length. Denervation might cause the SMC anomalies responsible for the detrusor altered contractile activity and intra-cellular traffic and favour the appearance of fibrosis. Inflammation might accelerate these damages. From the clinical point of view, an early anti-inflammatory treatment could positively influence the disease fate.

Lupeol inhibits LPS-induced neuroinflammation in cerebellar cultures and induces neuroprotection associated to the modulation of astrocyte response and expression of neurotrophic and inflammatory factors.

In the central nervous system (CNS), neuroinflammation, especially that modulated by the cell response of astrocytes and microglia, is associated with damage to neurons in neurodegenerative disorders such as Parkinson's disease, Alzheimer's disease and, Multiple Sclerosis. Lupeol is a dietary triterpene that has demonstrated biological activities as antioxidant. This study investigated the anti-inflammatory and neuroprotective effects of lupeol in an in vitro model of neuroinflammation in primary cerebellar cultures. Cultures were obtained from 6-day-old Wistar rats, subjected to inflammatory damage with lipopolysaccharide (LPS, 1 µg/mL) and treated with lupeol (0.1 µM). We observed, after a 48-hour treatment, through Fluorjade-B staining and immunocytochemistry (ICQ) for ßIII-tubulin, that lupeol induced neuroprotection in cultures submitted to inflammatory damage. On the other hand, through ICQ for GFAP, it was possible to observe that lupeol modulated the astrocyte morphology for Bergmann glia-like phenotype and, especially for velate astrocyte-like phenotype, both phenotypes associated with the neuroprotective profile. Moreover, RT-qPCR analysis showed that lupeol induced the down-regulation of the mRNA expression for proinflammatory markers TNF, iNOS and NLRP3, as well as the production of nitric oxide (method of Greiss), which were up-regulated by LPS, and also induced up-regulation of the mRNA expression for arginase and IL-6 mRNA. In addition, lupeol induced up-regulation of mRNA expression for neurotrophins GDNF and NGF and also for the sonic hedgehog-Gli pathway. Together, these results lead to the conclusion that lupeol inhibits neuroinflammation in cerebellar cultures and induces neuroprotection associated with the modulation of astrocyte response and expression of neurotrophic and inflammatory factors.

Luteoloside attenuates neuroinflammation in focal cerebral ischemia in rats via regulation of the PPARγ/Nrf2/NF-κB signaling pathway.

Luteoloside, a flavonoid compound, has been reported to have anti-inflammatory, anti-oxidative, antibacterial, antiviral, anticancer, and cardioprotective effects, among others, but its neuroprotective effects have rarely been studied. The purpose of this study was to investigate the protective effect of luteoloside on cerebral ischemia and explore its potential mechanism. Middle cerebral artery occlusion (MCAO) was performed to investigate the effects of luteoloside on cerebral ischemia-reperfusion (I/R). Male Sprague-Dawley rats were randomly divided into six groups: sham, MCAO, luteoloside (20 mg/kg, 40 mg/kg, 80 mg/kg) and nimodipine (4 mg/kg). The results showed that luteoloside alleviated neurologic deficits and cerebral edema as well as improved cerebral infarction and histopathological changes in MCAO rats. Luteoloside significantly inhibited I/R-induced neuroinflammation, as demonstrated by reduced levels of interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in the brain tissues of MCAO rats. Furthermore, our results demonstrated that luteoloside significantly suppressed the activation of nuclear factor-kappa B (NF-κB) signaling, upregulated the protein expression of peroxisome proliferator activated receptor gamma (PPARγ) and increased NF-E2-related factor (Nrf2) nuclear accumulation in MCAO rats. Collectively, our findings suggested that luteoloside played a crucial neuroprotective role by inhibiting NF-κB signaling in focal cerebral ischemia in rats. Furthermore, PPARγ and Nrf2 were also important for the anti-inflammatory effect of luteoloside. In addition, our data suggested that luteoloside might be an effective treatment for cerebral ischemia and other neurological disorders.

Minocycline attenuates ethanol-induced cell death and microglial activation in the developing spinal cord.

Developmental exposure to ethanol may cause fetal alcohol spectrum disorders (FASD), and the immature central nervous system (CNS) is particularly vulnerable to ethanol. In addition to vulnerability in the developing brain, we previously showed that ethanol also caused neuroapoptosis, microglial activation, and neuroinflammation in the spinal cord. Minocycline is an antibiotic that inhibits microglial activation and alleviates neuroinflammation. We sought to determine whether minocycline could protect spinal cord neurons against ethanol-induced damage. In this study, we showed that minocycline significantly inhibited ethanol-induced caspase-3 activation, microglial activation, and the expression of pro-inflammatory cytokines in the developing spinal cord. Moreover, minocycline blocked ethanol-induced activation of glycogen synthase kinase 3 beta (GSK3ß), a key regulator of microglial activation. Meanwhile, minocycline significantly restored ethanol-induced inhibition of protein kinase B (AKT), mammalian target of the rapamycin (mTOR), and ERK1/2 signaling pathways, which were important pro-survival signaling pathways for neurons. Together, minocycline may attenuate ethanol-induced damage to the developing spinal cord by inhibiting microglial activation/neuroinflammation and by restoring the pro-survival signaling.

Extracellular prolyl oligopeptidase derived from activated microglia is a potential neuroprotection target.

Prolyl oligopeptidase (PREP) is an abundant peptidase in the brain and periphery, but its physiological functions are still largely unknown. Recent findings point to a role for PREP in inflammatory processes. This study assessed the cellular and extracellular PREP activities in cultures of mouse primary cortical neurons, microglial cells and astrocytes, and immortalized microglial BV-2 cells under neuroinflammatory conditions induced by lipopolysaccharide (LPS) and interferon gamma (IFNγ). Furthermore, we evaluated the neuroprotective effect of a specific PREP inhibitor, KYP-2047, in a neuroinflammation model based on a coculture of primary cortical neurons and activated BV-2 cells. The inflammatory insult reduced intracellular and increased extracellular PREP activity specifically in microglial cells, suggesting that activated microglia excretes active PREP. A targeted proteomics approach revealed up-regulation in PREP protein levels in BV-2 cell growth medium but down-regulation in crude membrane-bound PREP after LPS+IFNγ. In the coculture of BV-2 cells and primary neurons, an increase in extracellular PREP activity was also detected after inflammation. KYP-2047 (10 µmol/L) significantly protected neurons against microglial toxicity and reduced the levels of the pro-inflammatory cytokine tumour necrosis factor alpha. In conclusion, these data point to an extracellular role for microglial PREP in the inflammatory process. Inhibition of PREP during neuroinflammation is a potential target for neuroprotection. Thus, PREP inhibitors may offer a novel therapeutic approach for the treatment of neurodegenerative disorders with an inflammatory component including Parkinson's and Alzheimer's diseases.

Vitamin C alleviates LPS-induced cognitive impairment in mice by suppressing neuroinflammation and oxidative stress.

Neuroinflammation is believed to be one of the primary causes of cognitive impairment. Previous studies showed that the antioxidant vitamin C (Vit C) performs many beneficial functions such as immunostimulant and anti-inflammatory actions, but its role in inflammatory cognitive impairment is unclear. In the current study, we investigated the effect and possible mechanism of action of Vit C in lipopolysaccharide (LPS)-induced cognitive impairment. Intracerebroventricular LPS-induced memory impairment was used as the model for neuroinflammatory cognitive dysfunction. Vit C was administered by intracerebroventricular microinjection 30 min prior to LPS exposure. It was found that Vit C significantly protected animals from LPS-induced memory impairment as evidenced by improved performance in the Morris water maze and novel object recognition tests without changes in spontaneous locomotor activity. Vit C pretreatment inhibited the activation of microglia and the production of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß). Furthermore, Vit C pretreatment markedly decreased the malondialdehyde (MDA) level, increased superoxide dismutase (SOD) activity, and modulated the Bax/Bcl-2 ratio and p-p38 MAPK activation in the hippocampus of LPS-treated mice. Together, these results suggest that vitamin C pretreatment could protect mice from LPS-induced cognitive impairment, possibly through the modulation of oxidative stress and inflammatory responses.

Anti-inflammatory effects of isoalantolactone on LPS-stimulated BV2 microglia cells through activating GSK-3ß-Nrf2 signaling pathway.

Isoalantolactone (ISO) is a sesquiterpene lactone isolated from Inula helenium that has been known to exhibit anti-inflammatory effect. Nevertheless, the effects of ISO on neuroinflammation have not been explored. BV2 microglia cells were pretreated with ISO and then stimulated with LPS. ISO attenuated the production of inflammatory mediators, such as TNF-α, IL-1ß, NO, and PGE2 in LPS-stimulated BV2 microglia cells. ISO suppressed the LPS-induced NF-κB activation in a concentration-dependent manner. The expression of Nrf2 and HO-1 were increased by the treatment of ISO. Inhibition of Nrf2 by siRNA could reverse the anti-inflammatory effects of ISO, as confirmed by the reversed inflammatory mediator production. Furthermore, ISO increased the level of phosphorylated GSK-3ß, the upstream molecule of Nrf2. In conclusion, these results indicated that ISO might exhibit its anti-inflammatory effects through activating GSK-3ß-Nrf2 signaling pathway.

Trigonelline mitigates lipopolysaccharide-induced learning and memory impairment in the rat due to its anti-oxidative and anti-inflammatory effect.

Brain inflammation is associated with cognitive dysfunction, especially in elderly. Trigonelline is a plant alkaloid and a major component of coffee and fenugreek with anti-diabetic, antioxidant, anti-inflammatory, and neuroprotective effects. In this study, the beneficial effect of trigonelline against lipopolysaccharide (LPS)-induced cognitive decline was assessed in the rat. LPS was injected i.p. at a dose of 500 µg/kg to induce neuroinflammation and trigonelline was administered p.o. at doses of 20, 40, or 80 mg/kg/day 1 h after LPS that continued for one week. Trigonelline-treated LPS-challenged rats showed improved spatial recognition memory in Y maze, discrimination ratio in novel object discrimination test, and retention and recall in passive avoidance paradigm. Additionally, trigonelline lowered hippocampal malondialdehyde (MDA) and acetylcholinesterase (AChE) activity and improved superoxide dismutase (SOD), catalase, and glutathione (GSH). Furthermore, trigonelline depressed hippocampal nuclear factor-kappaB (NF-κB), toll-like receptor 4 (TLR4), and tumor necrosis factor α (TNF α) in LPS-challenged rats. All of the effects of trigonelline followed a dose-dependent pattern and in some aspects, it acted even better than the routinely-used anti-inflammatory drug dexamethasone. Collectively, trigonelline is capable to diminish LPS-induced cognitive decline via suppression of hippocampal oxidative stress and inflammation and appropriate modulation of NF-κB/TLR4 and AChE activity.

Formononetin inhibits neuroinflammation and increases estrogen receptor beta (ERß) protein expression in BV2 microglia.

Formononetin is a bioactive non-steroidal polyphenol found in a variety of plants. In this study we evaluated the effects of formononetin on neuroinflammation in LPS-stimulated BV2 microglia. Results showed that formononetin significantly reduced the production of TNF-α, IL-6 and IL-1ß, nitrite and PGE2, as well as protein levels of iNOS and COX-2. Reporter gene assays showed that formononetin produced inhibition of NF-κB luciferase activity in HEK293 cells stimulated with TNF-α. Immunoblotting experiments revealed an inhibition of IKKα phosphorylation, with the resultant attenuation of phosphorylation and degradation of IκBα following LPS stimulation. Formononetin also produced an inhibition of nuclear translocation and DNA binding by NF-κB following LPS stimulation. RNAi experiments showed that transfection of BV2 microglia with ERß siRNA resulted in the loss of anti-inflammatory action of formononetin. MTT assay and MAP2 immunoreactivity experiments showed that formononetin produced significant neuroprotective activity by preventing BV2 microglia conditioned media-induced toxicity to HT22 neurons. Investigations on the effect of formononetin on MCF7 breast cancer cells revealed that, while the compound significantly increased ER-luciferase activity, its effects on proliferation were modest. This study has established that formononetin inhibits neuroinflammation by targeting NF-κB signalling pathway in BV2 microglia, possibly through mechanisms involving ERß. Formononetin appears to modulate ERß in MCF7 breast cancer cells with limited proliferative effect. Formononetin could therefore serve as a chemical scaffold for the development of novel compounds which have selective neuroprotective actions in the brain.

Protective role of ß-carotene against oxidative stress and neuroinflammation in a rat model of spinal cord injury.

Acute spinal cord injury (SCI) results in long-lasting functional impairments through both mechanical damage as well as secondary mechanisms, with limited available therapeutic options. ß-Carotene has been demonstrated to exert biological and pharmacological activities. We aimed to examine the protective effects of ß-carotene in a SCI rat model. We tested the hind-limb locomotor function, neuro-inflammation, oxidative stress, astrocyte activation and nuclear factor-κB (NF-κB) pathway activation of SCI rats, with or without ß-carotene treatment. ß-Carotene substantially improved locomotion that was reduced by SCI. ß-Carotene also relieved SCI-induced oxidative stress via regulation of reactive oxygen species, malondialdehyde, nitric oxide, and superoxide dismutase, as well as restored SCI-suppressed protein expressions of Nrf2 and HO-1. Additionally, ß-carotene decreased the generation of pro-inflammatory cytokines, including tumor necrosis factor-α, interleukin-1ß, interleukin-18 and cyclooxygenase-2, and inhibited the activation of astrocyte in the spinal cord. Furthermore, ß-carotene treatment markedly inhibited the NF-κB pathway activation. Our findings demonstrated that ß-carotene effectively reduced the progression of secondary injury events following SCI through preventing NF-κB pathway activation. Therefore, ß-carotene may be an effective candidate for treating SCI.

Esculentoside A exerts anti-inflammatory activity in microglial cells.

Esculentoside A (EsA) is a saponin isolated from the roots of Phytolacca esculenta. This study was designed to evaluate the pharmacological effects of EsA on lipopolysaccharide (LPS)-stimulated BV2 microglia and primary microglia cells. Our results indicated that EsA pretreatment significantly decreased LPS-induced production of Nitric Oxide (NO) and Prostaglandin E2 (PGE2) and impeded LPS-mediated upregulation of pro-inflammatory mediators' expression such as nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin-1ß (IL-1ß), interleukin-6 (IL-6), interleukin-12 (IL-12) and tumor necrosis factor-a (TNF-α) in both BV2 microglia and primary microglia cells. Moreover, EsA markedly suppressed nuclear factor-κB p65 (NF-κB p65) translocation by blocking IκB-α phosphorylation and degradation in LPS-treated BV2 cells. EsA also decreased phosphorylation level of mitogen-activated protein kinases (MAPKs) and inhibited NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome mediated caspase-1 activation in LPS-stimulated BV2 cells. Additionally, EsA decreased ß-amyloid1-42 (Aß1-42)-induced production of TNF-α, IL-1ß and IL-6 in primary microglia. Thus, EsA might be a promising therapeutic agent for alleviating neuroinflammatory diseases.