Mangiferin attenuates lipopolysaccharide-induced neuronal injuries in primary cultured hippocampal neurons.

Mangiferin, a naturally occurring potent glucosylxanthone, is mainly isolated from the Mangifera indica plant and shows potential pharmacological properties, including anti-bacterial, anti-inflammation, and antioxidant in sepsis-induced lung and kidney injury. However, there was a puzzle as to whether mangiferin had a protective effect on sepsis-associated encephalopathy. To answer this question, we established an in vitro cell model of sepsis-associated encephalopathy and investigated the neuroprotective effects of mangiferin in primary cultured hippocampal neurons challenged with lipopolysaccharide (LPS). Neurons treated with 20 µmol/L or 40 µmol/L mangiferin for 48 h can significantly reverse cell injuries induced by LPS treatment, including improved cell viability, decreased inflammatory cytokines secretion, relief of microtubule-associated light chain 3 expression levels and several autophagosomes, as well as attenuated cell apoptosis. Furthermore, mangiferin eliminated pathogenic proteins and elevated neuroprotective factors at both the mRNA and protein levels, showing strong neuroprotective effects of mangiferin, including anti-inflammatory, anti-autophagy, and anti-apoptotic effects on neurons in vitro.

Maackiain Prevents Amyloid-Beta-Induced Cellular Injury via Priming PKC-Nrf2 Pathway.

Amyloid-beta (Aß) peptide induces neurotoxicity through oxidative stress and inflammatory response. Brain deposition of a large amount of amyloid-beta (Aß), in particular Aß 42, promotes the development of Alzheimer's disease (AD). Maackiain is extracted from traditional Chinese medicine peony root and possesses antioxidative, antiosteoporosis, antitumor, and immunoregulatory effects. Whether Maackiain can reduce neurotoxicity caused by Aß accumulation remains elusive. Herein, we found that Maackiain downregulated Aß 42-induced cell injury and apoptosis in PC12 cells. Moreover, Maackiain prevented Aß 42 stimulation-induced generation of oxidative stress and reduced Aß 42-caused impairment of mitochondrial membrane potential in PC12 cells. Maackiain increased the superoxide dismutase activity and decreased malondialdehyde content that was induced by Aß 42. Mechanistic studies showed that Maackiain increased intranuclear Nrf2 expression. Consistently, Nrf2 silencing by RNA interference weakened the protective role of Maackiain against Aß exposure. In addition, calphostin C, a specific antagonist of protein kinase C, attenuated the promoting effects of Maackiain on Nrf2 nuclear translocation. Moreover, calphostin C attenuated the antioxidant and anti-inflammatory capabilities of Maackiain in PC12 cells. Collectively, Maackiain promoted Nrf2 activation through the PKC signaling pathway, thus preventing PC12 cells from Aß-induced oxidative stress and cell injury, suggesting that Maackiain is a potential drug for AD treatment.

Anaphylactic Rare Saponins Separated from Panax notoginseng Saponin and a Proteomic Approach to Their Anaphylactic Mechanism.

In recent years, many traditional Chinese medicine injections based on Panax notoginseng saponin (PNS) have been reported to cause anaphylaxis. Previous studies on the anaphylactic saponins of PNS and their mechanism are inadequate. In this study, potential anaphylactic saponins were obtained by the separation of PNS and preparation of each individual component through comprehensive techniques, such as liquid chromatography, preparative chromatography, HPLC, NMR, and MS. The anaphylactic abilities of these saponins were tested using RBL-2H3 cells via a ß-hexosaminidase release rate test. The results for the mechanism of anaphylaxis were obtained by a proteomic analysis using RBL-2H3 cells. The results indicate that, among all the saponins prepared, gypenoside LXXV and notoginsenoside T5 showed strong anaphylactic abilities and notoginsenoside ST-4 and ginsenoside Rk3 showed weak anaphylactic abilities. These 4 saponins can induce anaphylaxis via direct stimulation of effector cells. The gene oncology enrichment analysis results showed that, among these saponins, only gypenoside LXXV was related to organelles of the endoplasmic reticulum and Golgi apparatus and biological processes in response to organic cyclic compounds. Four proteins in RBL-2H3 cells with the accession numbers A0A0G2JWQ0, D3ZL85, D4A5G8, and Q8K3F0 were identified as crucial proteins in the anaphylactic process. This research will help traditional Chinese medicine injection manufacturers strengthen their quality control and ensure the safety of anaphylactic saponins.

Mechanisms and Molecular Targets of Compound Danshen Dropping Pill for Heart Disease Caused by High Altitude Based on Network Pharmacology and Molecular Docking.

Compound Danshen dropping pill (CDDP), a famous Chinese medicine formula, has been widely used to treat high-altitude heart disease in China. However, its molecular mechanisms, potential targets, and bioactive ingredients remain elusive. In this study, network pharmacology, molecular docking, and validation experiments were combined to investigate the effective active ingredients and molecular mechanisms of CDDP in the treatment of high-altitude heart disease. Tan IIA may be the main active component of CDDP in the treatment of high-altitude heart disease via HIF-1/PI3K/Akt pathways.

Global metabolomic and lipidomic analysis reveals the potential mechanisms of hemolysis effect of Ophiopogonin D and Ophiopogonin D' in vivo.

BACKGROUND: OPD and OPD' are the two main active components of Ophiopogon japonicas in Shenmai injection (SMI). Being isomers of each other, they are supposed to have similar pharmacological activities, but the actual situation is complicated. The difference of hemolytic behavior between OPD and OPD' in vivo and in vitro was discovered and reported by our group for the first time. In vitro, only OPD' showed hemolysis reaction, while in vivo, both OPD and OPD' caused hemolysis. In vitro, the primary cause of hemolysis has been confirmed to be related to the difference between physical and chemical properties of OPD and OPD'. In vivo, although there is a possible explanation for this phenomenon, the one is that OPD is bio-transformed into OPD' or its analogues in vivo, the other one is that both OPD and OPD' were metabolized into more activated forms for hemolysis. However, the mechanism of hemolysis in vivo is still unclear, especially the existing literature are still difficult to explain why OPD shows the inconsistent hemolysis behavior in vivo and in vitro. Therefore, the study of hemolysis of OPD and OPD' in vivo is of great practical significance in response to the increase of adverse events of SMI. METHODS: Aiming at the hemolysis in vivo, this manuscript adopted untargeted metabolomics and lipidomics technology to preliminarily explore the changes of plasma metabolites and lipids of OPD- and OPD'-treated rats. Metabolomics and lipidomics analyses were performed on ultra-high performance liquid chromatography (UPLC) system tandem with different mass spectrometers (MS) and different columns respectively. Multivariate statistical approaches such as principal component analysis (PCA) and orthogonal partial least square-discriminant analysis (OPLS-DA) were applied to screen the differential metabolites and lipids. RESULTS: Both OPD and OPD' groups experienced hemolysis, Changes in endogenous differential metabolites and differential lipids, enrichment of differential metabolic pathways, and correlation analysis of differential metabolites and lipids all indicated that the causes of hemolysis by OPD and OPD' were closely related to the interference of phospholipid metabolism. CONCLUSIONS: This study provided a comprehensive description of metabolomics and lipidomics changes between OPD- and OPD'-treated rats, it would add to the knowledge base of the field, which also provided scientific guidance for the subsequent mechanism research. However, the underlying mechanism require further research.

Author Correction: Ophiopogonin D maintains Ca2+ homeostasis in rat cardiomyocytes in vitro by upregulating CYP2J3/ EETs and suppressing ER stress.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

[Preliminary study of Realgar and arsenic trioxide on gut microbiota of mice].

The aim of this paper was to observe the effect of Realgar and arsenic trioxide on gut microbiota. The mice were divided into low-dose Realgar group(RL), medium-dose Realgar group(RM), high-dose Realgar group(RH), and arsenic trioxide group(ATO), in which ATO and RL groups had the same trivalent arsenic content. Realgar and arsenic trioxide toxicity models were established after intragastric administration for 1 week, and mice feces were collected 1 h after intragastric administration on day 8. The effects of Realgar on gut microbiota of mice were observed through bacterial 16 S rRNA gene sequences. The results showed that Lactobacillus was decreased in all groups, while Ruminococcus and Adlercreutzia were increased. The RL group and ATO group were consistent in the genera of Prevotella, Ruminococcus, and Adlercreutzia but different in the genera of Lactobacillus and Bacteroides. Therefore, the effects of Realgar and arsenic trioxide with the same amount of trivalent arsenic on gut microbiota were similar, but differences were still present. Protective bacteria such as Lactobacillus were reduced after Realgar administration, causing inflammation. At low doses, the number of anti-inflammatory bacteria, such as Ruminococcus, Adlercreutzia and Parabacteroides increased, which can offset the slight inflammation caused by the imbalance of bacterial flora. At high doses, the flora was disturbed and the number of Proteobacteria was increased, with aggravated intestinal inflammation, causing edema and other inflammatory reactions. Based on this, authors believe that the gastrointestinal reactions after clinical use of Realgar may be related to flora disorder. Realgar should be used at a small dose in combination with other drugs to reduce intestinal inflammation.

Mechanistic target of rapamycin-mediated autophagy is involved in the alleviation of lipopolysaccharide-induced acute lung injury in rats.

Acute lung injury (ALI) is a complex clinical syndrome with high morbidity and mortality rates. Autophagy is an adaptive process that plays a complex role in ALI. The aim of this study was to investigate the effects of autophagy on lipopolysaccharide (LPS)-induced lung injury by establishing a rat ALI model and to further explore the possible mechanisms involved. Rats were pretreated with the autophagy inhibitor 3-methyladenine (3-MA) or the autophagy activator rapamycin before they were challenged with the intratracheal instillation of LPS (5 mg/kg). The level of autophagy in the lung tissue was detected. Lung injury and vascular permeability were assessed. The role of the mechanistic target of rapamycin (mTOR)-mediated Unc-51-like kinase 1 (ULK1) and the class III PI3 kinase VPS34 in autophagy regulation was examined. LPS challenge induced autophagy and rapamycin pretreatment enhanced autophagy activity in LPS-induced ALI rats. LPS caused severe lung injury and high pulmonary vascular permeability, which could be alleviated by enhancing autophagy. In addition, the inhibition of mTOR upregulated the expression of ULK1 and VPS34 and thus increased LPS-induced autophagy. Autophagy plays a protective role in LPS-induced ALI, and enhancing autophagy via the inhibition of mTOR alleviates lung injury and pulmonary barrier function. Moreover, mTOR negatively mediates ULK1 and VPS34 to regulate LPS-induced autophagy in rats.

Ophiopogonin D Increases SERCA2a Interaction with Phospholamban by Promoting CYP2J3 Upregulation.

Ophiopogonin D (OPD), a compound from the Chinese herb Radix Ophiopogonis, reportedly induces increased levels of cytochrome P450 2J3 (CYP2J3)/epoxyeicosatrienoic acids (EETs) and Ca2+ in rat cardiomyocytes. Little is known regarding the specific mechanism between CYP2J3 and Ca2+ homeostasis. Here, we investigated whether CYP2J3 is involved in the protective action of OPD on the myocardium by activating the Ca2+ homeostasis-related protein complex (SERCA2a and PLB) in H9c2 rat cardiomyoblast cells. The interaction between SERCA2a and PLB was measured using fluorescence resonance energy transfer. OPD attenuated heart failure and catalyzed the active transport of Ca2+ into the sarcoplasmic reticulum by inducing the phosphorylation of PLB and promoting the SERCA2a activity. These beneficial effects of OPD on heart failure were abolished after knockdown of CYP2J3 in a model of heart failure. Together, our results identify CYP2J3 as a critical intracellular target for OPD and unravel a mechanism of CYP2J3-dependent regulation of intracellular Ca2+.

Mitochondrial Iron Overload-Mediated Inhibition of Nrf2-HO-1/GPX4 Assisted ALI-Induced Nephrotoxicity.

Aristolactam I (ALI) is an active component derived from some Traditional Chinese medicines (TCMs), and also the important metabolite of aristolochic acid. Long-term administration of medicine-containing ALI was reported to be related to aristolochic acid nephropathy (AAN), which was attributed to ALI-induced nephrotoxicity. However, the toxic mechanism of action involved is still unclear. Recently, pathogenic ferroptosis mediated lipid peroxidation was demonstrated to cause kidney injury. Therefore, this study explored the role of ferroptosis induced by mitochondrial iron overload in ALI-induced nephrotoxicity, aiming to identify the possible toxic mechanism of ALI-induced chronic nephropathy. Our results showed that ALI inhibited HK-2 cell activity in a dose-dependent manner and significantly suppressed glutathione (GSH) levels, accompanying by significant increases in intracellular 4-hydroxynonenal (4-HNE) and intracellular iron ions. Moreover, the ALI-mediated cytotoxicity could be reversed by deferoxamine mesylate (DFO). Compared with other inhibitors, Ferrostatin-1 (Fer-1), a ferroptosis inhibitor, obviously alleviated ALI-induced cytotoxicity. Furthermore, we have shown that ALI could remarkably increase the levels of superoxide anion and ferrous ions in mitochondria, and induce mitochondrial damage and condensed mitochondrial membrane density, the morphological characteristics of ferroptosis, all of which could be reversed by DFO. Interestingly, ALI dose-dependently inhibited these protein contents of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and glutathione peroxidase 4 (GPX4), which could be partly rescued by Tin-protoporphyrin IX (SnPP) and mitoTEMPO co-treatment. In conclusion, our results demonstrated that mitochondrial iron overload-mediated antioxidant system inhibition would assist ALI-induced ferroptosis in renal tubular epithelial cells, and Nrf2-HO-1/GPX4 antioxidative system could be an important intervention target to prevent medicine containing ALI-induced nephropathy.

[Ophiopogonin D protects cardiomyocytes against ophiopogonin D'-induced injury through suppressing endoplasmic reticulum stress].

This study is aimed to investigate the intervention effect and possible mechanism of ophiopogonin D( OPD) in protecting cardiomyocytes against ophiopogonin D'( OPD')-induced injury,and provide reference for further research on toxicity difference of saponins from ophiopogonins. CCK-8 assay was used to evaluate the effect of OPD and OPD' on cell viability. The effect of OPD on OPD'-induced cell apoptosis was measured by flow cytometry. Morphologies of endoplasmic reticulum were observed by endoplasmic reticulum fluorescent probe. PERK,ATF-4,Bip and CHOP mRNA levels were detected by Real-time quantitative polymerase chain reaction( PCR) analysis. ATF-4,phosphorylated PERK and e IF2α protein levels were detected by Western blot assay. RESULTS:: showed that treatment with OPD'( 6 µmol·L-1) significantly increased the rate of apoptosis; expressions of endoplasmic reticulum stress related genes were increased. The morphology of the endoplasmic reticulum was changed. In addition,different concentrations of OPD could partially reverse the myocardial cell injury caused by OPD'. The experimental results showed that OPD'-induced myocardial toxicity may be associated with the endoplasmic reticulum stress,and OPD may modulate the expression of CYP2 J3 to relieve the endoplasmic reticulum stress caused by OPD'.

[Aconitine ameliorates cardiomyocyte hypertrophy induced by angiotensin â ¡].

This paper was aimed to investigate the inhibitory effect of aconitine(AC) on angiotensin Ⅱ(Ang Ⅱ)-induced H9 c2 cell hypertrophy and explore its mechanism of action. The model of hypertrophy was induced by Ang Ⅱ(1×10-6 mol·L-1),and cardiomyocytes were incubated with different concentrations of AC. Western blot was used to quantify the protein expression levels of atrial natriuretic peptide(ANP),brain natriuretic peptide(BNP),ß-myosin heavy chain(ß-MHC),and α-smooth muscle actin(α-SMA). Real-time quantitative PCR(qRT-PCR) was used to quantify the mRNA expression levels of cardiac hypertrophic markers ANP,BNP and ß-MHC. In addition,the fluorescence intensity of the F-actin marker,an important component of myofibrils,was detected by using laser confocal microscope. AC could significantly reverse the increase of total protein content in H9 c2 cells induced by Ang Ⅱ; qRT-PCR results showed that AC could significantly inhibit the ANP,BNP and ß-MHC mRNA up-regulation induced by AngⅡ. Western blot results showed that AC could significantly inhibit the ANP,BNP and ß-MHC protein up-regulation induced by AngⅡ. In addition,F-actin expression induced by Ang Ⅱ could be inhibited by AC,and multiple indicators of cardiomyocyte hypertrophy induced by Ang Ⅱ could be down-regulated,indicating that AC may inhibit cardiac hypertrophy by inhibiting the expression of hypertrophic factors,providing new clues for exploring the cardiovascular protection of AC.

Astragalus membranaceus and Salvia miltiorrhiza Ameliorate Lipopolysaccharide-Induced Acute Lung Injury in Rats by Regulating the Toll-Like Receptor 4/Nuclear Factor-Kappa B Signaling Pathway.

Astragalus membranaceus and Salvia miltiorrhiza (AM/SM) are well used in Traditional Chinese Medicines (TCM) for nourishing Qi and activating blood circulation method. From TCM theory, the pathogenesis of acute lung injury (ALI) was determined as Qi deficiency and blood stagnation. In this study, we are aiming to investigate the protective and therapeutic effects of AM/SM on a rat model of lipopolysaccharide- (LPS-) induced ALI in rats and to elucidate potential molecular mechanisms. ALI was induced by intratracheal instillation of LPS (5 mg/kg) in Sprague-Dawley rats. SM/AM was given orally before and after LPS administration. Results demonstrated that AM/SM attenuated lung histopathological changes induced by LPS, decreased wet/dry weight ratios and protein concentrations, and inhibited the production of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in BALF. Moreover, AM/SM significantly downregulated protein and mRNA expression of toll-like receptors 4 (TLR-4), interleukin-1 receptor-associated kinase-1 (IRAK-1), and nuclear factor-kappa B (NF-κB/p65). These findings suggest that AM/SM showed protective and therapeutic effects in LPS-induced ALI rat through modulating TLR-4 signaling pathways. Nourishing Qi and activating blood circulation may be a beneficial treatment for ALI.

[Protective effect of ginsenoside Rb1 on doxorubicin-induced myocardial autophagy].

Ginsenoside Rb1 (Rb1), which is one of the main ingredients derived from Panax ginseng, has been found to have extensive pharmacological activities including antioxidant, anti-inflammatory, anticancer properties. In this study, the effect of Rb1 on doxorubicin-induced myocardial autophagy was studied with H9c2 as the study object. CCK-8 method, transmission electron microscope observation, fluorescence staining observation and Western blot were used to detect changes in H9c2 cell proliferation and autophagy after treatment. According to the results, doxorubicin could cause cell viability decrease, significant increase in the LC3-Ⅱ/LC3-I ratio and down-regulation of the expression of p62. Pretreatment with ginsenoside Rb1 inhibited cell viability decrease and increase in doxorubicin-induced autophagic structure and LC3-Ⅱ/LC3-I ratio, and down-regulation of the expression of p62. In conclusion, doxorubicin could induce H9c2 cell death and induce autophagy, and ginsenoside Rb1 showed a protective effect on DOX-induced cardiotoxicity, which may be correlated with suppression of DOX-induced autophagy.

[Effect of clinical doses of Realgar-Indigo Naturalis formula and large-dose of realgar on CYP450s of rat liver].

To investigate the effect of clinical dose of Realgar-Indigo Naturais formula (RIF) and large-dose of Realgar on main drug-metabolizing enzymes CYP450s of rat liver, as well as its regulatory effect on mRNA expression. Wistar rats were administrated orally with tested drugs for 14 days. A Cocktail method combined with HPLC-MS/MS was used in the determination of 4 cytochrome P450 isozymes (CYP1A2, CYP2B, CYP3A and CYP2C) in liver of the rats, and the mRNA expression levels of the above subtypes were detected by real-time fluorescent quantitative PCR. The results showed that RIF can significantly induce CYP1A2 and CYP2B enzyme activity, and inhibit CYP3A enzyme activity. This result was consistent with the mRNA expression. However, its single compound showed weaker or even contrary phenomenon. Different doses of Realgar also showed significant inconsistencies on CYP450 enzymes activity and mRNA expression. These phenomena may be relevant with RIF compatibility synergies or toxicity reduction. The results can also prompt drug interactions when RIF is combined with other medicines in application.

Influences of Realgar-Indigo naturalis, A Traditional Chinese Medicine Formula, on the Main CYP450 Activities in Rats Using a Cocktail Method.

The purpose of this work was to study the influences of Realgar-Indigo naturalis (RIF) and its principal element realgar on 4 main cytochrome P450 enzymes activities in rats. A simple and efficient cocktail method was developed to detect the four probe drugs simultaneously. In this study, Wistar rats were administered intragastric RIF and realgar for 14 days; mixed probe drugs were injected into rats by caudal vein. Through analyzing the pharmacokinetic parameter of mixed probe drugs in rats, we can calculate the CYPs activities. The results showed that RIF could inhibit CYP1A2 enzyme activity and induce CYP2C11 enzyme activity significantly. Interestingly, in realgar high dosage group, CYP3A1/2 enzyme activity was inhibited significantly, and different dosage of realgar manifested a good dose-dependent manner. The RIF results indicated that drug coadministrated with RIF may need to be paid attention in relation to drug-drug interactions (DDIs). Realgar, a toxic traditional Chinese medicine (TCM), does have curative effect on acute promyelocytic leukemia (APL). Its toxicity studies should be focused on. We found that, in realgar high dosage group, CYP3A1/2 enzymes activity was inhibited. This phenomenon may explain its potential toxicity mechanism.

Tanshinone IIA Protects Endothelial Cells from H2O2-Induced Injuries via PXR Activation.

Tanshinone IIA (Tan IIA) is a pharmacologically active substance extracted from the rhizome of Salvia miltiorrhiza Bunge (also known as the Chinese herb Danshen), and is widely used to treat atherosclerosis. The pregnane X receptor (PXR) is a nuclear receptor that is a key regulator of xenobiotic and endobiotic detoxification. Tan IIA is an efficacious PXR agonist that has a potential protective effect on endothelial injuries induced by xenobiotics and endobiotics via PXR activation. Previously numerous studies have demonstrated the possible effects of Tan IIA on human umbilical vein endothelial cells, but the further mechanism for its exerts the protective effect is not well established. To study the protective effects of Tan IIA against hydrogen peroxide (H2O2) in human umbilical vein endothelial cells (HUVECs), we pretreated cells with or without different concentrations of Tan IIA for 24 h, then exposed the cells to 400 µM H2O2 for another 3 h. Therefore, our data strongly suggests that Tan IIA may lead to increased regeneration of glutathione (GSH) from the glutathione disulfide (GSSG) produced during the GSH peroxidase-catalyzed decomposition of H2O2 in HUVECs, and the PXR plays a significant role in this process. Tan IIA may also exert protective effects against H2O2-induced apoptosis through the mitochondrial apoptosis pathway associated with the participation of PXR. Tan IIA protected HUVECs from inflammatory mediators triggered by H2O2 via PXR activation. In conclusion, Tan IIA protected HUVECs against H2O2-induced cell injury through PXR-dependent mechanisms.

Ginsenoside Rb1 Inhibits Doxorubicin-Triggered H9C2 Cell Apoptosis via Aryl Hydrocarbon Receptor.

Doxorubicin (DOX) is a highly effective chemotherapeutic agent; however, the dose-dependent cardiotoxicity associated with DOX significantly limits its clinical application. In the present study, we investigated whether Rb1 could prevent DOX-induced apoptosis in H9C2 cells via aryl hydrocarbon receptor (AhR). H9C2 cells were treated with various concentrations (- µM) of Rb1. AhR, CYP1A protein and mRNA expression were quantified with Western blot and real-time PCR analyses. We also evaluated the expression levels of caspase-3 to assess the anti-apoptotic effects of Rb1. Our results showed that Rb1 attenuated DOX-induced cardiomyocytes injury and apoptosis and reduced caspase-3 and caspase-8, but not caspase-9 activity in DOX-treated H9C2 cells. Meanwhile, pre-treatment with Rb1 decreased the expression of caspase-3 and PARP in the protein levels, with no effects on cytochrome c, Bax, and Bcl-2 in DOX-stimulated cells. Rb1 markedly decreased the CYP1A1 and CYP1A2 expression induced by DOX. Furthermore, transfection with AhR siRNA or pre-treatment with AhR antagonist CH-223191 significantly inhibited the ability of Rb1 to decrease the induction of CYP1A, as well as caspase-3 protein levels following stimulation with DOX. In conclusion, these findings indicate that AhR plays an important role in the protection of Ginsenoside Rb1 against DOX-triggered apoptosis of H9C2 cells.

Ferulic acid prevents LPS-induced up-regulation of PDE4B and stimulates the cAMP/CREB signaling pathway in PC12 cells.

AIM: Phosphodiesterase 4 (PDE4) isozymes are involved in different functions, depending on their patterns of distribution in the brain. The PDE4 subtypes are distributed in different inflammatory cells, and appear to be important regulators of inflammatory processes. In this study we examined the effects of ferulic acid (FA), a plant component with strong anti-oxidant and anti-inflammatory activities, on lipopolysaccharide (LPS)-induced up-regulation of phosphodiesterase 4B (PDE4B) in PC12 cells, which in turn regulated cellular cAMP levels and the cAMP/cAMP response element binding protein (CREB) pathway in the cells. METHODS: PC12 cells were treated with LPS (1 µg/mL) for 8 h, and the changes of F-actin were detected using laser scanning confocal microscopy. The levels of pro-inflammatory cytokines were measured suing ELISA kits, and PDE4B-specific enzymatic activity was assessed with a PDE4B assay kit. The mRNA levels of PDE4B were analyzed with Q-PCR, and the protein levels of CREB and phosphorylated CREB (pCREB) were determined using immunoblotting. Furthermore, molecular docking was used to identify the interaction between PDE4B2 and FA. RESULTS: Treatment of PC12 cells with LPS induced thick bundles of actin filaments appearing in the F-actin cytoskeleton, which were ameliorated by pretreatment with FA (10-40 µmol/L) or with a PDE4B inhibitor rolipram (30 µmol/L). Pretreatment with FA dose-dependently inhibited the LPS-induced production of TNF-α and IL-1ß in PC12 cells. Furthermore, pretreatment with FA dose-dependently attenuated the LPS-induced up-regulation of PDE4 activity in PC12 cells. Moreover, pretreatment with FA decreased LPS-induced up-regulation of the PDE4B mRNA, and reversed LPS-induced down-regulation of CREB and pCREB in PC12 cells. The molecular docking results revealed electrostatic and hydrophobic interactions between FA and PDE4B2. CONCLUSION: The beneficial effects of FA in PC12 cells might be conferred through inhibition of LPS-induced up-regulation of PDE4B and stimulation of cAMP/CREB signaling pathway. Therefore, FA may be a potential therapeutic intervention for the treatment of neuroinflammatory diseases such as AD.