Probiotics and Postbiotics as an Alternative to Antibiotics: An Emphasis on Pigs.

Probiotics are being used as feed/food supplements as an alternative to antibiotics. It has been demonstrated that probiotics provide several health benefits, including preventing diarrhea, irritable bowel syndrome, and immunomodulation. Alongside probiotic bacteria-fermented foods, the different structural components, such as lipoteichoic acids, teichoic acids, peptidoglycans, and surface-layer proteins, offer several advantages. Probiotics can produce different antimicrobial components, enzymes, peptides, vitamins, and exopolysaccharides. Besides live probiotics, there has been growing interest in consuming inactivated probiotics in farm animals, including pigs. Several reports have shown that live and killed probiotics can boost immunity, modulate intestinal microbiota, improve feed efficiency and growth performance, and decrease the incidence of diarrhea, positioning them as an interesting strategy as a potential feed supplement for pigs. Therefore, effective selection and approach to the use of probiotics might provide essential features of using probiotics as an important functional feed for pigs. This review aimed to systematically investigate the potential effects of lactic acid bacteria in their live and inactivated forms on pigs.

Hypothalamic inflammation in metabolic disorders and aging.

The hypothalamus is a critical brain region for the regulation of energy homeostasis. Over the years, studies on energy metabolism primarily focused on the neuronal component of the hypothalamus. Studies have recently uncovered the vital role of glial cells as an additional player in energy balance regulation. However, their inflammatory activation under metabolic stress condition contributes to various metabolic diseases. The recruitment of monocytes and macrophages in the hypothalamus helps sustain such inflammation and worsens the disease state. Neurons were found to actively participate in hypothalamic inflammatory response by transmitting signals to the surrounding non-neuronal cells. This activation of different cell types in the hypothalamus leads to chronic, low-grade inflammation, impairing energy balance and contributing to defective feeding habits, thermogenesis, and insulin and leptin signaling, eventually leading to metabolic disorders (i.e., diabetes, obesity, and hypertension). The hypothalamus is also responsible for the causation of systemic aging under metabolic stress. A better understanding of the multiple factors contributing to hypothalamic inflammation, the role of the different hypothalamic cells, and their crosstalks may help identify new therapeutic targets. In this review, we focus on the role of glial cells in establishing a cause-effect relationship between hypothalamic inflammation and the development of metabolic diseases. We also cover the role of other cell types and discuss the possibilities and challenges of targeting hypothalamic inflammation as a valid therapeutic approach.

Investigation of Potential Antioxidant, Thrombolytic and Neuropharmacological Activities of Homalomena aromatica Leaves Using Experimental and In Silico Approaches.

The leaves of Homalomena aromatica are traditionally used in Bangladesh for the treatment of different chronic ailments. The purpose of this study was to explore in vitro antioxidant, thrombolytic activities, and in vivo neuropharmacological effects of methanolic extract of Homalomena aromatica (MEHA) leaves. Antioxidant activity of MEHA was assessed by a DPPH free radical scavenging assay and total phenolics content, total flavonoids content were also measured. The thrombolytic activity was determined by percentage of clot lysis and neuropharmacological activities by hole board, tail suspension, forced swimming and elevated plus maze tests. The results showed that the IC50 value of the extract against DPPH was 199.51 µg/mL. Quantitative analysis displayed higher contents of phenolics and flavonoids (147.71 mg gallic acid equivalent/g & 66.65 mg quercetin equivalent/g dried extract, respectively). The extract also showed a significant clot lysis (33.31%) activity. In case of anxiolytic activity, the elevate plus maze (EPM) test demonstrated an increase in time spent in open arms, and in case of hole board test, the number of head dipping was also significantly increased (p < 0.05). All the test compared with control (1% Tween in water) and standard (diazepam 1 mg/kg), significant dose (200 & 400 mg/kg) dependent anxiolytic activity was found. In antidepressant activity, there was a significant decrease in period of immobility in both test models (tail suspension and forced swimming) (p < 0.05). Moreover, 13 compounds were identified as bioactive, showed good binding affinities to xanthine oxidoreductase, tissue plasminogen activator receptor, potassium channel receptor, human serotonin receptor targets in molecular docking experiments. Furthermore, ADME/T analysis revealed their drug-likeness, likely pharmacological actions and non-toxic upon consumption. Taken together, our finding support the traditional medicinal use of this plant, which may provide a potential source for future drug discovery.

Astrocytic pyruvate dehydrogenase kinase-2 is involved in hypothalamic inflammation in mouse models of diabetes.

Hypothalamic inflammation plays an important role in disrupting feeding behavior and energy homeostasis as well as in the pathogenesis of obesity and diabetes. Here, we show that pyruvate dehydrogenase kinase (PDK)-2 plays a role in hypothalamic inflammation and its sequelae in mouse models of diabetes. Cell type-specific genetic ablation and pharmacological inhibition of PDK2 in hypothalamic astrocytes suggest that hypothalamic astrocytes are involved in the diabetic phenotype. We also show that the PDK2-lactic acid axis plays a regulatory role in the observed metabolic imbalance and hypothalamic inflammation in mouse primary astrocyte and organotypic cultures, through the AMPK signaling pathway and neuropeptidergic circuitry governing feeding behavior. Our findings reveal that PDK2 ablation or inhibition in mouse astrocytes attenuates diabetes-induced hypothalamic inflammation and subsequent alterations in feeding behavior.

Cellular Contributors to Hypothalamic Inflammation in Obesity.

The hypothalamus is a crucial organ for the maintenance of appropriate body fat storage. Neurons in the hypothalamic arcuate nucleus (ARH) detect energy shortage or surplus via the circulating concentrations of metabolic hormones and nutrients, and then coordinate energy intake and expenditure to maintain energy homeostasis. Malfunction or loss of hypothalamic ARH neurons results in obesity. Accumulated evidence suggests that hypothalamic inflammation is a key pathological mechanism that links chronic overconsumption of a high-fat diet (HFD) with the development of obesity and related metabolic complications. Interestingly, overnutrition-induced hypothalamic inflammation occurs specifically in the ARH, where microglia initiate an inflammatory response by releasing proinflammatory cytokines and chemokines in response to excessive fatty acid flux. Upon more prolonged HFD consumption, astrocytes and perivascular macrophages become involved and sustain hypothalamic inflammation. ARH neurons are victims of hypothalamic inflammation, but they may actively participate in hypothalamic inflammation by sending quiescence or stress signals to surrounding glia. In this mini-review, we describe the current state of knowledge regarding the contributions of neurons and glia, and their interactions, to HFD-induced hypothalamic inflammation.

Neuroprotective and Anti-Neuroinflammatory Effects of a Poisonous Plant Croton Tiglium Linn. Extract.

Neuroinflammation is involved in various neurological diseases. Activated microglia secrete many pro-inflammatory factors and induce neuronal cell death. Thus, the inhibition of excessive proinflammatory activity of microglia leads to a therapeutic effect that alleviates the progression of neuronal degeneration. In this study, we investigated the effect of Croton tiglium(C. tiglium) Linn. extract (CTE) on the production of pro- and anti-inflammatory mediators in microglia and astrocytes via RT-PCR, Western blot, and nitric oxide assay. Neurotoxicity was measured by cell viability assay and GFP image analysis. Phagocytosis of microglia was measured using fluorescent zymosan particles. CTE significantly inhibited the production of neurotoxic inflammatory factors, including nitric oxide and tumor necrosis factor-α. In addition, CTE increased the production of the neurotrophic factor, brain-derived neurotrophic factor, and the M2 phenotype of microglia. The culture medium retained after CTE treatment increased the survival of neurons, thereby indicating the neuroprotective effect of CTE. Our findings indicated that CTE inhibited pro-inflammatory response and increased the neuroprotective ability of microglia. In conclusion, although CTE is known to be a poisonous plant and listed on the FDA poisonous plant database, it can be used as a medicine if the amount is properly controlled. Our results suggested the potential benefits of CTE as a therapeutic agent for different neurodegenerative disorders involving neuroinflammation.

Hypothalamic inflammation and malfunctioning glia in the pathophysiology of obesity and diabetes: Translational significance.

Preclinical studies have suggested that chronic inflammation in the brain might be associated with multiple metabolic disorders, including obesity and diabetes. In particular, hypothalamic inflammation interferes with the endocrine system and modulates nutritional homeostasis, leading to metabolic alterations and consequent pathologies. With regard to the mechanisms underlying molecular and cellular pathogenesis, neurons, non-neuronal cells, and the crosstalk between them have gained particular attention. Specifically, malfunctioning glia have recently been implicated as an important component of pathological hypothalamic inflammation. Hypothalamic inflammation modulates food intake, energy expenditure, insulin secretion, hepatic glucose production, and glucose and fatty acid metabolism. Moreover, growing evidence suggests that hypothalamic inflammation is intrinsically associated with the pathogenesis of obesity, diabetes, and their dysfunctional consequences. However, the translational significance of hypothalamic inflammation has not yet been fully explored. In this review, we cover recent advances suggesting that hypothalamic inflammation and glia play a central role in the ontology of obesity, diabetes, and their complications. Finally, we explore the possibilities and challenges of targeting hypothalamic inflammation as a potential therapeutic strategy.

Hypothalamic lipid-laden astrocytes induce microglia migration and activation.

Obesity-induced hypothalamic inflammation is closely associated with various metabolic complications and neurodegenerative disorders. Astrocytes, the most abundant glial cells in the central nervous system, play a crucial role in pathological hypothalamic inflammatory processes. Here, we demonstrate that hypothalamic astrocytes accumulate lipid droplets under saturated fatty acid-rich conditions, such as obese environment, and that the lipid-laden astrocytes increase astrogliosis markers and inflammatory cytokines (TNFα, IL-1ß, IL-6, MCP-1) at the transcript and/or protein level. Medium conditioned by the lipid-laden astrocytes stimulate microglial chemotactic activity and upregulate transcripts of the microglia activation marker Iba-1 and inflammatory cytokines. These findings indicate that the lipid-laden astrocytes formed in free fatty acid-rich obese condition may participate in obesity-induced hypothalamic inflammation through promoting microglia migration and activation.

Chronic sleep deprivation-induced proteome changes in astrocytes of the rat hypothalamus.

Sleep deprivation (SD) can influence cognition, memory, and sleep/wake homeostasis and can cause impairments in many physiological processes. Because the homeostatic control of the sleep/wake cycle is closely associated with the hypothalamus, the current study was undertaken to examine proteomic changes occurring in hypothalamic astrocytes following chronic partial SD. After chronic partial SD for 7 days, astrocytes were prepared from rat hypothalamus using a Percoll gradient method, and their proteome profiles were determined by LC-MS/MS. Comparisons of the proteome profiles of hypothalamic astrocytes revealed that chronic partial SD increased (≥1.5-fold) 89 proteins and decreased (≤0.7-fold) 50 proteins; these changes in protein expression were validated by western blot or immunohistochemistry. DAVID and IPA analyses of these proteins suggested that SD may influence gliotransmission and astrocyte activation. PPP2R1A, RTN4, VAMP-2, LGI-1, and SLC17A7 were identified and validated as the main targets of SD in astrocytes. Our results suggest that SD may modulate gliotransmission in the hypothalamus, thereby disturbing sleep/wake homeostasis and increasing susceptibility to neurological disease; however, further studies are required to confirm whether the proteome changes are specific to SD.

Natural flavone jaceosidin is a neuroinflammation inhibitor.

Jaceosidin is a naturally occurring flavone with pharmacological activity. Jaceosidin, as one of the major constituents of the medicinal herbs of the genus Artemisia, has been shown to exert anticancer, anti-oxidative, anti-inflammatory, and immunosuppressive effects. This study was undertaken to determine the effect of jaceosidin on microglia and neuroinflammation. Microglia are the innate immune cells in the central nervous system, and they play a central role in the initiation and maintenance of neuroinflammation. We report that jaceosidin inhibits inflammatory activation of microglia, reducing nitric oxide (NO) production and proinflammatory cytokine expression. IC50 for NO inhibition was 27 ± 0.4 µM. The flavone also attenuated microglial neurotoxicity in the microglia/neuroblastoma co-culture. Systemic injection of jaceosidin ameliorated neuroinflammation in the mouse model of experimental allergic encephalomyelitis. These results indicate that plant flavone jaceosidin is a microglial inhibitor with anti-neuroinflammation activity.

Effects of obovatol on GSH depleted glia-mediated neurotoxicity and oxidative damage.

Earlier studies indicate that obovatol (OBO), isolated from a medicinal herb Magnolia obovata, has anti-inflammatory and anti-oxidative properties. Depletion of glutathione (GSH) in glial cells with the γ-glutamylcysteine synthase inhibitor D,L-buthionine-S,R-sulfoximine (BSO) is known to produce oxidative stress which, in turn, induces these cells to secrete inflammatory cytokines and other neurotoxic substances. In the present study, we investigated the ability of OBO to protect SH-SY5Y neuroblastoma cells from this effect. Human microglia, astrocytes and their surrogate THP-1 and U373 cell lines were activated by treatment with BSO. Such treatment depleted their intracellular GSH and increased levels of damage to DNA, lipids and proteins (8-OHdG, lipid peroxide, protein carbonyls and 3-nitrotyrosine), and activated the inflammatory pathways P38 MAP kinase and NFκB. These are accompanied by release of proinflammatory factors such as TNFα, IL-6 and nitric oxide. Their conditioned media were toxic to SH-SY5Y cells. All these effects were attenuated by pre-treatment with OBO. Prior treatment of SH-SY5Y cells with OBO also attenuated THP-1 or U373 conditioned media neurotoxicity and also reduced oxidative damage produced by treatment with hydrogen peroxide or BSO. Prior treatment with OBO potentiated survival of SH-SY5Y cells exposed to conditioned medium from BSO-treated THP-1, U373 cells, microglia and astrocytes. The data indicate that OBO could be anti-inflammatory, anti-oxidative and neuroprotective, and be an effective agent for inhibiting pathogenesis in neurological diseases such as Alzheimer disease, Parkinson disease and amyotrophic lateral sclerosis in which glial-mediated neuroinflammation and oxidative stress are thought to contribute to disease progression.

Suppression of mast-cell-mediated allergic inflammation by Lindera obtusiloba.

Allergic disease is a consequence of exposure to normally innocuous substances that elicit the activation of mast cells. Mast-cell-mediated allergic response is involved in many diseases such as anaphylaxis, allergic rhinitis, asthma and atopic dermatitis. The discovery of drugs for the treatment of allergic disease is an important subject in human health. In this study, we investigated the effect of Lindera obtusiloba water extract (LOWE) on the mast-cell-mediated allergic inflammation and possible mechanism of action using in vitro and in vivo models. LOWE reduced histamine release from various types of mast cells activated by immunoglobulin E (IgE) or phorbol 12-myristate 13-acetate and calcium ionophore A23187 (PMACI). The inhibitory effect of LOWE on histamine release was mediated by calcium signal. LOWE decreased the PMACI-stimulated gene expression of proinflammatory cytokines such as tumor necrosis factor-α and interleukin-6 in human mast cells. The inhibitory effect of LOWE on the proinflammatory cytokines was nuclear factor (NF)-κB dependent. In addition, LOWE suppressed compound 48/80-induced systemic allergic reaction and serum histamine release in mice and IgE-mediated local allergic reactions. Our results indicate that LOWE inhibits mast-cell-derived allergic inflammation and involvement of calcium, histamine, proinflammatory cytokines and NF-κB in these effects.

Inhibitors of microglial neurotoxicity: focus on natural products.

Microglial cells play a dual role in the central nervous system as they have both neurotoxic and neuroprotective effects. Uncontrolled and excessive activation of microglia often contributes to inflammation-mediated neurodegeneration. Recently, much attention has been paid to therapeutic strategies aimed at inhibiting neurotoxic microglial activation. Pharmacological inhibitors of microglial activation are emerging as a result of such endeavors. In this review, natural products-based inhibitors of microglial activation will be reviewed. Potential neuroprotective activity of these compounds will also be discussed. Future works should focus on the discovery of novel drug targets that specifically mediate microglial neurotoxicity rather than neuroprotection. Development of new drugs based on these targets may require a better understanding of microglial biology and neuroinflammation at the molecular, cellular, and systems levels.

2'-Hydroxycinnamaldehyde targets low-density lipoprotein receptor-related protein-1 to inhibit lipopolysaccharide-induced microglial activation.

2'-Hydroxycinnamaldehyde (HCA) isolated from the stem bark of Cinnamomum cassia and its derivative 2'-benzoyloxycinnamaldehyde (BCA) were reported to have anti-angiogenic, anti-proliferative, and anti-inflammatory effects in several human cancer cells and RAW 264.7 macrophage cells. However, effects of HCA/BCA on the neuroinflammation have not been investigated. In the present study, a potential anti-neuroinflammatory effect of HCA/BCA was assessed in lipopolysaccharide (LPS)-stimulated microglial cultures and microglia/neuroblastoma cocultures. Nitric oxide production, inflammatory gene expression, and signaling pathways were investigated. HCA/BCA significantly decreased the production of nitric oxide and tumor necrosis factor-alpha (TNF-α) in microglial cells. HCA/BCA also attenuated the expression of inducible nitric oxide synthase (iNOS) and pro-inflammatory cytokines such as interleukin-1ß (IL-1ß) and TNF-α at mRNA level via blockade of ERK, JNK, p38 MAPK, and NF-κB activation. Moreover, HCA/BCA was neuroprotective by reducing microglia-mediated neuroblastoma cell death in a microglia-neuroblastoma co-culture. Affinity chromatography and LC-MS/MS analysis identified low-density lipoprotein receptor-related protein 1 (LRP1) as a potential molecular target of HCA in microglial cells. Based on the studies using the receptor-associated protein (RAP) that blocks a ligand binding to LRP1 and the siRNA-mediated LRP1 gene silencing, we were able to conclude that HCA inhibited LPS-induced microglial activation via LRP1. Our results suggest that HCA/BCA be anti-inflammatory and neuroprotective in the CNS by targeting LRP1, and may have a therapeutic potential against neuroinflammatory diseases.

Clinopodium gracile inhibits mast cell-mediated allergic inflammation: involvement of calcium and nuclear factor-kappaB.

Mast cell-mediated allergic disease is involved in many diseases such as anaphylaxis, rhinitis, asthma and atopic dermatitis. The discovery of drugs for the treatment of allergic disease is an important subject in human health. In this study, we investigated the effect of the water extract of Clinopodium gracile Matsum var. multicaule (WECG) on the mast cell-mediated allergic inflammation and studied the possible mechanism of action. WECG inhibited compound 48/80-induced systemic anaphylaxis and immunoglobulin E-mediated cutaneous anaphylaxis in a dose-dependent manner. WECG dose-dependently reduced histamine release from rat peritoneal mast cells and human mast cells. The inhibitory effect of WECG on histamine release was mediated by the modulation of intracellular calcium. In addition, WECG attenuated the phorbol 12-myristate 13-acetate and calcium ionophore A23187-stimulated gene expression and secretion of proinflammatory cytokines such as tumor necrosis factor-alpha and interleukin-6 in human mast cells. The inhibitory effect of WECG on these proinflammatory cytokines was nuclear factor-kappaB (NF-kappaB) dependent. Our findings provide evidence that WECG inhibits mast cell-derived allergic inflammation and involvement of calcium and NF-kappaB in these effects.

Obovatol attenuates microglia-mediated neuroinflammation by modulating redox regulation.

BACKGROUND AND PURPOSE: Obovatol isolated from the medicinal herb Magnolia obovata exhibits a variety of biological activities. Here, the effect of obovatol and its mechanism of action on microglial activation, neuroinflammation and neurodegeneration were investigated. EXPERIMENTAL APPROACH: In microglial BV-2 cells stimulated with lipopolysaccharide (LPS), we measured nitric oxide (NO) and cytokine production, and activation of intracellular signalling pathways by reverse transcription-polymerase chain reaction and Western blots. Cell death was assayed in co-cultures of activated microglia (with bacterial LPS) and neurons and in LPS- induced neuroinflammation in mice in vivo. KEY RESULTS: Obovatol inhibited microglial NO production with an IC50 value of 10 mM. Obovatol also inhibited microglial expression of proinflammatory cytokines and inducible nitric-oxide synthase, which was accompanied by the inhibition of multiple signalling pathways such as nuclear factor kappa B, signal transducers and activators of transcription 1, and mitogen-activated protein kinases. In addition, obovatol protected cultured neurons from microglial toxicity and inhibited neuroinflammation in mice in vivo. One molecular target of obovatol in microglia was peroxiredoxin 2 (Prx2), identified by affinity chromatography and mass spectrometry. Obovatol enhanced the reactive oxygen species (ROS)-scavenging activity of Prx2 in vitro, thereby suppressing proinflammatory signalling pathways of microglia where ROS plays an important role. CONCLUSIONS AND IMPLICATIONS: Obovatol is not only a useful chemical tool that can be used to investigate microglial signalling, but also a promising drug candidate against neuroinflammatory diseases. Furthermore, our results indicate that Prx2 is a novel drug target that can be exploited for the therapeutic modulation of neuroinflammatory signalling.

Inhibition of microglial neurotoxicity by ethanol extract of Artemisia asiatica Nakai.

Artemisia asiatica Nakai has been used for the treatment of infections and inflammatory disorders in traditional Oriental medicine. Previously, an ethanol extract of A. asiatica has been shown to exert antioxidative and antiinflammatory activities and to exhibit protective effects against experimentally induced damage in the gastrointestinal system, liver and pancreas. This study examined whether the ethanol extract of A. asiatica affects inflammatory activation of microglia in the central nervous system, and whether the antiinflammatory activity of A. asiatica is related to neuroprotective effects. The extract of A. asiatica inhibited inflammatory activation of mouse microglial cells as determined by the production of nitric oxide and the expression of inducible nitric oxide synthase and inflammatory cytokine. The extract also protected nerve growth factor-differentiated PC12 cells against microglial cytotoxicity, indicating that the ethanol extract of A. asiatica may be neuroprotective by inhibiting microglial neurotoxicity.

Heme oxygenase-1 mediates cytoprotective effects of immunostimulation in microglia.

Microglia are brain-resident immune cells playing a pivotal role in the neuroinflammation. Previously, it has been shown that immunostimulation protects microglial cells against nitric oxide toxicity. Herein, we report that heme oxygenase-1 (HO-1) mediates the protective effects of immunostimulation. Pro-inflammatory activation of BV-2 microglial cells with endotoxin lipopolysaccharide (LPS) conferred a protection against various cytotoxic stimuli, whereas anti-inflammatory cytokines such as IL-4 and IL-10 were without effects. The LPS-induced cytoprotection was accompanied by HO-1 induction. The cytoprotective effect of LPS treatment was significantly attenuated by co-treatment with a HO-1 inhibitor, zinc protoporphyrin. Adenoviral expression of HO-1 in microglial cells was similarly cytoprotective, indicating that HO-1 mediates the cytoprotective effects of pro-inflammatory stimulation. Additional experiments revealed the involvement of carbon monoxide (CO) and iron, products of HO-1-mediated heme degradation, in the cytoprotective effect of LPS. Taken together, our results suggest that immunostimulation of microglia with LPS provides cytoprotective effects via HO-1 induction followed by the generation of CO and iron.

Upregulation of PBR mRNA expression in human neuroblastoma cells by flavonoids.

To investigate the putative mediation of peripheral benzodiazepine receptor (PBR) in the cytotoxicity of flavonoids, in this study, modulatory effects of several flavonoids on the lipid peroxide (LPO) production and PBR mRNA expression of human neuroblastoma cells were observed. Elevated levels of peroxidated products in cancer cells may activate pro-apoptotic and anti-proliferative signaling pathways. Treatment of 10(-6) M 4'-chlorodiazepam and PK 11195 ligands of the PBR for 6 days enhanced the generation of LPO of the human neuroblastoma cells. Several flavonoids, well-known cytotoxic substances, potentiated the enhancement of LPO production by PBR ligands. Treatment of 10(-6) M flavonoids for 6 days elevated the expression of PBR mRNA in cells. These findings indicate that the potential of flavonoids to induce apoptosis in cancer cells is strongly associated with their PBR-inducing properties, thereby providing a new mechanism by which polyphenolic compounds may exert their cancer-preventive and anti-neoplastic effects.

Decursin inhibits induction of inflammatory mediators by blocking nuclear factor-kappaB activation in macrophages.

In the course of screening inhibitors of matrix metalloproteinase (MMP)-9 induction in macrophages, we isolated decursin, a coumarin compound, from the roots of Angelicae gigas. As a marker for the screening and isolation, we tested expression of MMP-9 in RAW264.7 cells and THP-1 cells after treatment with bacterial lipopolysaccharide (LPS), the TLR-4 ligand. Decursin suppressed MMP-9 expression in cells stimulated by LPS in a dose-dependent manner at concentrations below 60 microM with no sign of cytotoxicity. The suppressive effect of decursin was observed not only in cells stimulated with ligands for TLR4, TLR2, TLR3, and TLR9 but also in cells stimulated with interleukin (IL)-1beta, and tumor necrosis factor (TNF)-alpha, indicating that the molecular target of decursin is common signaling molecules induced by these stimulants. In addition to the suppression of MMP-9 expression, decursin blocked nitric oxide production and cytokine (IL-8, MCP-1, IL-1beta, and TNF-alpha) secretion induced by LPS. To find out the molecular mechanism responsible for the suppressive effect of decursin, we analyzed signaling molecules involved in the TLR-mediated activation of MMP-9 and cytokines. Decursin blocked phosphorylation of IkappaB and nuclear translocation of NF-kappaB in THP-1 cells activated with LPS. Furthermore, expression of a luciferase reporter gene under the promoter containing NF-kappaB binding sites was blocked by decursin. These data indicate that decursin is a novel inhibitor of NF-kappaB activation in signaling induced by TLR ligands and cytokines.