Inhibitory effect of inflexinol on nitric oxide generation and iNOS expression via inhibition of NF-kappaB activation

Two new terpenoid glycosides from Isodon macrocalyx

One previously undescribed tricyclo-diterpenoid saponin (1), one undescribed dammarane triterpenoid saponin (2) and four known triterpenoids (3-6) were isolated from the aerial part of Isodon macrocalyx. Their structures were determined using 1 D- and 2 D-NMR, HRESIMS, and comparison of their spectroscopic data with previously reported data. The isolates were evaluated for their anti-HBV activity in vitro using the HBV transfected Hep G2.2.15 cell line. Compounds 2 and 3 exhibited moderate anti-HBV activity.

Ethnobotanical, Phytochemical, and Pharmacological Properties of the Subfamily Nepetoideae (Lamiaceae) in Inflammatory Diseases

Nepetoideae is the most diverse subfamily of Lamiaceae, and some species are well known for their culinary and medicinal uses. In recent years, there has been growing interest in the therapeutic properties of the species of this group regarding inflammatory illnesses. This study aims to collect information on traditional uses through ethnobotanical, pharmacological, and phytochemical information of the subfamily Nepetoideae related to inflammatory diseases. UNAM electronic resources were used to obtain the information. The analysis of the most relevant literature was compiled and organised in tables. From this, about 106 species of the subfamily are traditionally recognised to alleviate chronic pain associated with inflammation. Pharmacological studies have been carried out in vitro and in vivo on approximately 308 species belonging to the genera Salvia, Ocimum, Thymus, Mentha, Origanum, Lavandula, and Melissa. Phytochemical and pharmacological evaluations have been performed and mostly prepared as essential oil or high polarity extracts, whose secondary metabolites are mainly of a phenolic nature. Other interesting and explored metabolites are diterpenes from the abietane, clerodane, and kaurane type; however, they have only been described in some species of the genera Salvia and Isodon. This review reveals that the Nepetoideae subfamily is an important source for therapeutics of the inflammatory process.

Modular analysis of bioinformatics demonstrates a critical role for NF-κB in macrophage activation

To achieve the goal of identifying the gene groups that regulated macrophage activation, a total of 925 differentially expressed genes of activated macrophages were found at the intersection of the three series (GSE5099-1, GSE5099-2, and GSE18686) from the Gene Expression Omnibus (GEO) database, and a sub-network was constructed based on the protein-protein interaction (PPI) network. Four communities (K = 3) were identified from the sub-network using the CFinder software. Community 1 was considered as the gene group of interest base on the heat map. GO-BP and KEGG enrichment analysis with the DAVID software showed that the functions of the 14 genes in community 1 were mainly related to the NF-κB pathway. A network was constructed using the Cytoscape software. The diagram showed that STAT1, NFKBIA, NFKAIB, JUN, and RELA were the key genes in the regulation of macrophage activation. Among these genes, RELA (NF-κB P65) was an important member of the NF-κB family, while NFKBIA (IκBα) and NFKAIB (IκBβ) were the inhibitory factors of NF-κB. Small molecules capable of regulating these five genes were identified via the CMap software, and a network diagram was generated using the Cytoscape software to provide a reference for the development of new drugs that regulate macrophage activation.

Expression of 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) and its roles in activated microglia in vivo and in vitro

Background

We reported previously that amoeboid microglial cells in the postnatal rat brain expressed 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNPase) both in vivo and in vitro; however, the functional role of CNPase in microglia has remained uncertain. This study extended the investigation to determine CNPase expression in activated microglia derived from cell culture and animal models of brain injury with the objective to clarify its putative functions.

Methods

Three-day-old Wistar rats were given an intraperitoneal injection of lipopolysaccharide to induce microglial activation, and the rats were killed at different time points. Along with this, primary cultured microglial cells were subjected to lipopolysaccharide treatment, and expression of CNPase was analyzed by real-time reverse transcription PCR and immunofluorescence. Additionally, siRNA transfection was employed to downregulate CNPase in BV-2 cells. Following this, inducible nitric oxide synthase, IL-1β and TNF-α were determined at mRNA and protein levels. Reactive oxygen species and nitric oxide were also assessed by flow cytometry and colorimetric assay, respectively. In parallel to this, CNPase expression in activated microglia was also investigated in adult rats subjected to fluid percussion injury as well as middle cerebral artery occlusion.

Results

In vivo, CNPase immunofluorescence in activated microglia was markedly enhanced after lipopolysaccharide treatment. A similar feature was observed in the rat brain after fluid percussion injury and middle cerebral artery occlusion. In vitro, CNPase protein and mRNA expression was increased in primary microglia with lipopolysaccharide stimulation. Remarkably, inducible nitric oxide synthase, IL-1β, TNF-α, reactive oxygen species and nitric oxide were significantly upregulated in activated BV-2 cells with CNPase knockdown. siRNA knockdown of CNPase increased microglia migration; on the other hand, microglial cells appeared to be arrested at G1 phase.

Conclusions

The present results have provided the first morphological and molecular evidence that CNPase expression is increased in activated microglia. CNPase knockdown resulted in increased expression of various inflammatory mediators. It is concluded that CNPase may play an important role as a putative anti-inflammatory gene both in normal and injured brain.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-014-0148-9) contains supplementary material, which is available to authorized users.

Ligusticum wallichii Extract Inhibited the Expression of IL-1β after AMI in Rats

This study investigated the effects of Ligusticum wallichii on IL-1β expression in myocardium and central nervous system after AMI. AMI rat was administrated with Ligusticum wallichii extract. A series of assays were used to detect the effects of Ligusticum wallichii extract on infarct size, left ventricular ejection fraction, expression of TLR-4, NF-κB, and IL-1β in myocardium, IL-1β expression in serum and hypothalamus, and NPY expression in hypothalamus. We observed that Ligusticum wallichii extract improved the left ventricular ejection fraction and reduced infarct area enlargement after AMI, by inhibiting the expression of IL-1β in myocardium, serum, and hypothalamus. Ligusticum wallichii extract reduced the expression of IL-1β in myocardium by regulating TLR4-NF-κB signaling pathway and inhibited IL-1β in hypothalamus by regulating NPY mRNA expression.

Trehalose alleviates PC12 neuronal death mediated by lipopolysaccharide-stimulated BV-2 cells via inhibiting nuclear transcription factor NF-κB and AP-1 activation

Inflammation is implicated in the pathogenesis of Parkinson's disease (PD). Trehalose is a disaccharide which exhibits a variety of effects like anti-aggregation, autophagy enhancement in PD. It has also been known to suppress inflammation in many experimental models, involving endotoxin shock, murine dry eye and subarachnoid hemorrhage. However, whether trehalose has an anti-inflammation effect on PD is largely unknown. In the present study, we found trehalose inhibited generation of interleukin-1β, interleukin-6, tumor necrosis factor-α, and nitric oxide in the conditioned medium released from lipopolysaccharide (LPS)-stimulated BV-2 cells. LPS-induced nuclear transcription factors of NF-κB and AP-1 activation were also inhibited by trehalose. Then the conditioned medium of BV-2 cells was applied to PC12 neurons. As a result, both MTT and LDH indicated that trehalose decreased PC12 neuronal death. TUNEL assay showed that trehalose suppressed apoptosis of PC12 neurons. These results implied that trehalose exerted a protective effect on PC12 neurons against the neurotoxic effect triggered by BV-2 microglial activation through inhibiting NF-κB and AP-1 activation and inflammatory mediators and cytokines production in BV-2 cells.

Inhibitory effect of ent-Sauchinone on amyloidogenesis via inhibition of STAT3-mediated NF-κB activation in cultured astrocytes and microglial BV-2 cells

Background

ent-Sauchinone is a polyphenolic compound found in plants belonging to the lignan family. ent-Sauchinone has been shown to modulate the expression of inflammatory factors through the nuclear factor-kappa B (NF-κB) signaling pathway. It is well known that neuroinflammation is associated with amyloidogenesis. Thus, in the present study, we investigated whether ent-Sauchinone could have anti-amyloidogenic effects through the inhibition of NF-κB pathways via its anti-inflammatory property.

Methods

To investigate the potential effect of ent-Sauchinone on anti-neuroinflammation and anti-amyloidogenesis in in vitro studies, we used microglial BV-2 cells and cultured astrocytes treated with ent-Sauchinone (1, 5, and 10 μM) for 24 hours. For the detection of anti-neuro-inflammatory responses, reative oxygen species (ROS) and Nitric oxide (NO) generation and inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression were measured with assay kits and western blotting. β-secretase and β-secretase activities and β-amyloid levels were determined for measuring the anti-amyloidogenic effects of ent-Sauchinone by enzyme assay kits. NF-κB and STAT3 signals were detected with electromobility shift assay (EMSA) to study the related signaling pathways. The binding of ent-Sauchinone to STAT3 was evaluated by a pull-down assay and by a docking model using Autodock VINA software (Hoover’s Inc., Texas, United states).

Results

ent-Sauchinone (1, 5, and 10 μM) effectively decreased lipopolysaccharide (LPS)-(1 μg/ml) induced inflammatory responses through the reduction of ROS and NO generations and iNOS and COX-2 expressions in cultured astrocytes and microglial BV-2 cells. ent-Sauchinone also inhibited LPS-induced amyloidogenesis through the inhibition of β-secretase and β-secretase activity. NF- κB amyloid and STAT3, critical transcriptional factors regulating not only inflammation but also amyloidogenesis, were also inhibited in a concentration dependent manner by ent-Sauchinone by blocking the phosphorylation of I κB and STAT3 in cultured astrocytes and microglial BV-2 cells. The docking model approach showed that ent-Sauchinone binds to STAT3, and the employment of a STAT3 inhibitor and siRNA reversed ent-Sauchinone-induced inhibition NF-κB activation and Aβ generation.

Conclusions

These results indicated that ent-Sauchinone inhibited neuroinflammation and amyloidogenesis through the inhibition of STAT3-mediated NF-κB activity, and thus could be applied in the treatment of neuro-inflammatory diseases, including Alzheimer’s disease.

Anti-inflammatory effects of saponins derived from the roots of Platycodon grandiflorus in lipopolysaccharide‑stimulated BV2 microglial cells

Radix platycodi is the root of Platycodon grandiflorus A. DC, which has been widely used as a food material and for the treatment of a number of chronic inflammatory diseases in traditional oriental medicine. In this study, the anti‑inflammatory effects of the saponins isolated from radix platycodi (PGS) on the production of inflammatory mediators and cytokines in lipopolysaccharide (LPS)-stimulated BV2 murine microglial cells were examined. We also investigated the effects of PGS on LPS‑induced nuclear factor‑κB (NF-κB) activation and phosphoinositide 3-kinase (PI3K)/AKT and mitogen-activated protein kinase (MAPK) signaling pathways. Following stimulation with LPS, elevated nitric oxide (NO), prostaglandin E2 (PGE2) and pro-inflammatory cytokine production was detected in the BV2 microglial cells. However, PGS significantly inhibited the excessive production of NO, PGE2 and pro‑inflammatory cytokines, including interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in a concentration-dependent manner without causing any cytotoxic effects. In addition, PGS suppressed NF-κB translocation and inhibited the LPS-induced phosphorylation of AKT and MAPKs. Our results indicate that the inhibitory effect of PGS on LPS-stimulated inflammatory response in BV2 microglial cells is associated with the suppression of NF-κB activation and the PI3K/AKT and MAPK signaling pathways. Therefore, these findings suggest that PGS may be useful in the treatment of neurodegenerative diseases by inhibiting inflammatory responses in activated microglial cells.

Ganoderma lucidum ethanol extract inhibits the inflammatory response by suppressing the NF-κB and toll-like receptor pathways in lipopolysaccharide-stimulated BV2 microglial cells

Ganoderma lucidum is a traditional Oriental medicine that has been widely used as a tonic to promote longevity and health in Korea and other Asian countries. Although a great deal of work has been carried out on the therapeutic potential of this mushroom, the pharmacological mechanisms of its anti-inflammatory actions remain unclear. In this study, we evaluated the inhibitory effects of G. lucidum ethanol extract (EGL) on the production of inflammatory mediators and cytokines in lipopolysaccharide (LPS)-stimulated murine BV2 microglia. We also investigated the effects of EGL on the LPS-induced activation of nuclear factor kappaB (NF-κB) and upregulation of toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 (MyD88). Elevated levels of nitric oxide (NO), prostaglandin E(2) (PGE(2)) and pro-inflammatory cytokine production were detected in BV2 microglia following LPS stimulation. We identifed that EGL significantly inhibits the excessive production of NO, PGE(2) and pro-inflammatory cytokines, including interleukin (IL)-1β and tumor necrosis factor-α in a concentration-dependent manner without causing cytotoxicity. In addition, EGL suppressed NF-κB translocation and transcriptional activity by blocking IκB degradation and inhibiting TLR4 and MyD88 expression in LPS-stimulated BV2 cells. Our results indicate that the inhibitory effects of EGL on LPS-stimulated inflammatory responses in BV2 microglia are associated with the suppression of the NF-κB and TLR signaling pathways. Therefore, EGL may be useful in the treatment of neurodegenerative diseases by inhibiting inflammatory mediator responses in activated microglia.

Inflexinol reduces severity of acute pancreatitis by inhibiting nuclear factor-κB activation in cerulein-induced pancreatitis

OBJECTIVES

To examine the effect of inflexinol on the development of acute pancreatitis (AP) and to investigate the mechanisms responsible for the protective effect against AP.

METHODS

Acute pancreatitis was induced in mice by intraperitoneal injection of cerulein. Inflexinol was administered intraperitoneally 4 times every 6 hours from 1 hour before the first cerulein injection. Serum amylase activity and histology of the pancreas were measured. Determination of pancreatic nuclear factor-κB (NF-κB) p65 expression was conducted by Western blotting and immunohistochemistry to investigate the mechanisms responsible for the inflexinol effects.

RESULTS

Serum amylase activity in the cerulein group was significantly higher than that in the control group (P < 0.05). Pancreatic histology revealed marked inflammatory changes in the cerulein group such as interstitial edema, vacuolization, necrosis, and infiltration of inflammatory cells; and Western blotting and immunohistochemistry showed marked NF-κB p65 expression. Treatment with inflexinol significantly attenuated the inflammatory changes in pancreatic histology at 24, 48, and 72 hours (P < 0.05). Pancreatic NF-κB p65 expression decreased significantly after inflexinol treatment (P < 0.05).

CONCLUSION

Inflexinol reduced the severity of cerulein-induced AP by inhibiting NF-κB activation.

Anthocyanins downregulate lipopolysaccharide-induced inflammatory responses in BV2 microglial cells by suppressing the NF-κB and Akt/MAPKs signaling pathways

Anthocyanins are naturally occurring polyphenols that impart bright color to fruits, vegetables and plants and have a variety of protective properties, which have generally been attributed to their antioxidant capacity. However, little is known about the molecular mechanisms underlying anti-inflammatory effects of anthocyanins related to neurodegenerative diseases. Therefore, we determined whether anthocyanins isolated from black soybean seed coats would inhibit pro-inflammatory mediators and cytokines in lipopolysaccharide (LPS)-stimulated murine BV2 microglial cells. Our results showed that anthocyanins significantly inhibited LPS-induced pro-inflammatory mediators, such as nitric oxide (NO) and prostaglandin E(2), and pro-inflammatory cytokines including tumor necrosis factor (TNF)-α and interleukin (IL)-1β, without significant cytotoxicity. Anthocyanins also downregulated excessive expression of inducible NO synthase, cyclooxygenase-2, TNF-α, and IL-1β in LPS-stimulated BV2 cells. Moreover, anthocyanins inhibited nuclear translocation of nuclear factor-kappa B (NF-κB) by reducing inhibitor of NF-κB alpha degradation as well as phosphorylating extracellular signal-regulated kinase, c-Jun N-terminal kinase, p38 mitogen-activated protein kinase, and Akt. These findings suggest that anthocyanins may offer substantial therapeutic potential for treating inflammatory and neurodegenerative diseases accompanied by microglial activation.

Catalpol inhibits LPS plus IFN-γ-induced inflammatory response in astrocytes primary cultures

A large body of evidence suggests that the inflammatory reaction plays an important role in the pathogenesis of neurodegenerative diseases. Our previous studies described the neuroprotective effects of catalpol in lipopolysaccharide (LPS)-induced inflammatory models, in which catalpol was shown to prevent mesencephalic neuron death and ameliorate cognitive ability animals. To further investigate the protective effect and underlying mechanism of catalpol, astrocytes were pretreated with low (0.1mM) and high dose (0.5mM) catalpol for 1h prior to LPS plus interferon-γ stimulation. Biochemical analyses showed that NO and ROS production and iNOS activity were significantly reduced by catalpol. Data at transcriptional level also demonstrated that catalpol potently attenuated gene expressions involved in inflammation, such as iNOS, COX-2 and TLR4. In addition, our exploration further revealed that the suppressive action of catalpol on inflammation was mediated via inhibiting nuclear factor-κB (NF-κB) activation. Collectively, these results suggest that catalpol can exert inhibitory effects on the inflammatory reaction in astrocytes and that inactivation of NF-κB could be the major determinant for its anti-inflammatory mechanism. Therefore, catalpol may potentially be a highly effective therapeutic agent in treating neurodegenerative diseases associated with inflammation.

Exopolysaccharide of Laetiporus sulphureus var. miniatus downregulates LPS-induced production of NO, PGE₂, and TNF-α in BV2 microglia cells via suppression of the NF-κB pathway

Our previous study showed that the exopolysaccharide (EPS) of Laetiporus sulphureus var. miniatus was well characterized and prevented cell damage in streptozotocin-induced apoptosis. However, little is known about the molecular mechanisms underlying its anti-inflammatory effects. Therefore, we attempted in this study to determine whether EPS induces a significant inhibition of pro-inflammatory mediators in lipopolysaccharide (LPS)-stimulated murine BV2 microglia cells. Our results showed that EPS significantly inhibited LPS-induced pro-inflammatory mediators, such as nitric oxide (NO), prostaglandin E(2) (PGE(2)), and tumor necrosis factor-α (TNF-α), without any significant cytotoxicity. EPS also downregulated mRNA and protein expression of inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), and TNF-α in LPS-induced BV2 microglia cells. Our data also revealed that EPS treatment significantly reduced translocation of nuclear factor-κB (NF-κB) subunit p65 and its DNA-binding activity in LPS-stimulated BV2 microglia cells. Furthermore, we confirmed by using proteasome inhibitor N-acetyl-l-cysteine (NAC), that the inhibition of NF-κB activity influenced the expression of pro-inflammatory genes in LPS-induced BV2 microglia cells. As expected, NAC suppressed the expression of iNOS, COX-2, and TNF-α by blocking proteasome-mediated degradation. Taken together, our data indicate that EPS inhibits the expression of pro-inflammatory mediators by suppressing NF-κB activity.

Differential effects of salvinorin A on endotoxin-induced hypermotility and neurogenic ion transport in mouse ileum

BACKGROUND

Salvinorin A (SA) is the principal active ingredient of Salvia divinorum, with an established inhibitory action on gastrointestinal (GI) transit and colonic ion transport in mice. Under normal conditions, the effects of SA are mediated by kappa opioid (KOR) and cannabinoid (CB1 and CB2) receptors. However, the role of SA in pathophysiological conditions remains unresolved. The aim of this study was to characterize the in vitro and in vivo effects of SA on mouse ileum after endotoxin challenge.

METHODS

Changes in GI motility were studied in vitro, using smooth muscle preparations from the mouse ileum. In vivo, the fecal pellet output and small intestinal fluid content were measured. Neurogenic ion transport and intestinal permeability were examined using Ussing chambers. In addition, Western blot analysis of mucosa was performed and plasma nitrite/nitrate levels were determined.

KEY RESULTS

Salvinorin A inhibited endotoxin-induced ileal hypercontractility via KOR, CB1, and CB2 receptors. Neurogenic ion transport, which was significantly reduced after endotoxin challenge, was normalized by SA through a nitric oxide synthase (NOS)-dependent mechanism. Western blot analysis and plasma nitrite/nitrate level quantitation confirmed the involvement of NOS in the regulatory action of SA.

CONCLUSIONS & INFERENCES

This is the first report showing differential effects of SA on motor and secretory activity in mouse GI during endotoxemia. The outcomes of our study imply possible novel applications of SA and its analogs in the treatment of GI disorders.

Inflexinol inhibits colon cancer cell growth through inhibition of nuclear factor-kappaB activity via direct interaction with p50

Kaurane diterpene compounds have been known to be cytotoxic against several cancer cells through inhibition of nuclear factor-kappaB (NF-kappaB) activity. Here, we showed that inflexinol, a novel kaurane diterpene compound, inhibited the activity of NF-kappaB and its target gene expression as well as cancer cell growth through induction of apoptotic cell death in vitro and in vivo. These inhibitory effects on NF-kappaB activity and on cancer cell growth were suppressed by the reducing agents DTT and glutathione and were abrogated in the cells transfected with mutant p50 (C62S). Sol-gel biochip and surface plasmon resonance analysis showed that inflexinol binds to the p50 subunit of NF-kappaB. These results suggest that inflexinol inhibits colon cancer cell growth via induction of apoptotic cell death through inactivation of NF-kappaB by a direct modification of cysteine residue in the p50 subunit of NF-kappaB.

Mycoplasma genitalium lipoproteins induce human monocytic cell expression of proinflammatory cytokines and apoptosis by activating nuclear factor kappaB

This study was designed to investigate the molecular mechanisms responsible for the induction of proinflammatory cytokines gene expression and apoptosis in human monocytic cell line THP-1 stimulated by lipoproteins (LPs) prepared from Mycoplasma genitalium. Cultured cells were stimulated with M. genitalium LP to analyze the production of proinflammatory cytokines and expression of their mRNA by ELISA and RT-PCR, respectively. Cell apoptosis was also detected by Annexin V-FITC-propidium iodide (PI) staining and acridine orange (AO)-ethidium bromide (EB) staining. The DNA-binding activity of nuclear factor-κB (NF-κB) was assessed by electrophoretic mobility shift assay (EMSA). Results showed that LP stimulated THP-1 cells to produce tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6 in a dose-dependent manner. The mRNA levels were also upregulated in response to LP stimulation. LPs were also found to increase the DNA-binding activity of NF-κB, a possible mechanism for the induction of cytokine mRNA expression and the cell apoptosis. These effects were abrogated by PDTC, an inhibitor of NF-κB. Our results indicate that M. genitalium-derived LP may be an important etiological factor of certain diseases due to the ability of LP to produce proinflammatory cytokines and induction of apoptosis, which is probably mediated through the activation of NF-κB.

Progesterone prevents traumatic brain injury-induced intestinal nuclear factor kappa B activation and proinflammatory cytokines expression in male rats

We have previously shown that traumatic brain injury (TBI) can induce an upregulation of nuclear factor kappa B (NF-κB) and proinflammatory cytokines in the gut, which play an important role in the pathogenesis of acute gut mucosal injury mediated by inflammation. In this work, we investigated whether progesterone administration modulated intestinal NF-κB activity and proinflammatory cytokines expression after TBI in male rats. As a result, we found that administration of progesterone following TBI could decrease NF-κB binding activity, NF-κB p65 protein expression, and concentrations of interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) in the gut. TBI-induced damages of gut structure were ameliorated after progesterone injections. The results of the present study suggest that the therapeutic benefit of post-TBI progesterone injections might be due to its inhibitory effects on intestinal NF-κB activation and proinflammatory cytokines expression.