scholarly journals Sesamin: A Naturally Occurring Lignan Inhibits CYP3A4 by Antagonizing the Pregnane X Receptor Activation

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Yun-Ping Lim ◽  
Chia-Yun Ma ◽  
Cheng-Ling Liu ◽  
Yu-Hsien Lin ◽  
Miao-Lin Hu ◽  
...  
Keyword(s):  
Drug Effects ◽  
Pregnane X Receptor ◽  
Therapeutic Index ◽  
Receptor Activation ◽  
Dependent Manner ◽  
Metabolizing Enzymes ◽  
Sesame Seeds ◽  
Common Causes ◽  
Underlying Mechanisms ◽  
Dose Dependent

Inconsistent expression and regulation of drug-metabolizing enzymes (DMEs) are common causes of adverse drug effects in some drugs with a narrow therapeutic index (TI). An important cytochrome, cytochrome P450 3A4 (CYP3A4), is predominantly regulated by a nuclear receptor, pregnane X receptor (PXR). Sesamin, a major lignan constituent in sesame seeds and oil, exhibits a variety of biological functions; however, the effect of sesamin on the modulation of CYP3A4 is not well understood. In this study, the effects of sesamin on the PXR-CYP3A4 pathway were characterized, as well as the underlying mechanisms of those effects. Sesamin potently attenuated CYP3A4 induction in a dose-dependent manner by blocking the activation of PXR. The PXR inducer-mediated inhibition of CYP3A4 was further evidenced by the ability of sesamin to attenuate the effects of several PXR ligands in the CYP3A4 reporter assay. Further mechanistic studies showed that sesamin inhibited PXR by interrupting the interacting with coregulators. These results may lead to the development of new therapeutic and dietary approaches to reduce the frequency of inducer-drug interaction. Sesamin was established as a novel inhibitor of PXR and may be useful for modulating DMEs expression and drug efficacies. Modification of CYP3A4 expression and activity by consumption of sesamin may have important implications for drug safety.

Polydatin Attenuates Carbachol-induced Contraction of Guinea Pig Gallbladder

2019 ◽  
Vol 18 (1) ◽  
pp. 34-38
Author(s):  
Chen Lei ◽  
Pan Xiang ◽  
Shen Yonggang ◽  
Song Kai ◽  
Zhong Xingguo ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Guinea Pig ◽  
Smooth Muscles ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Cyclic Guanosine Monophosphate ◽  
Guanosine Monophosphate ◽  
Dependent Manner ◽  
Underlying Mechanisms ◽  
Dose Dependent

The aim of this study was to determine whether polydatin, a glucoside of resveratrol isolated from the root of Polygonum cuspidatum, warranted development as a potential therapeutic for ameliorating the pain originating from gallbladder spasm disorders and the underlying mechanisms. Guinea pig gallbladder smooth muscles were treated with polydatin and specific inhibitors to explore the mechanisms underpinning polydatin-induced relaxation of carbachol-precontracted guinea pig gallbladder. Our results shown that polydatin relaxed carbachol-induced contraction in a dose-dependent manner through the nitric oxide/cyclic guanosine monophosphate/protein kinase G and the cyclic adenosine monophosphate/protein kinase A signaling pathways as well as the myosin light chain kinase and potassium channels. Our findings suggested that there was value in further exploring the potential therapeutic use of polydatin in gallbladder spasm disorders.

Presynaptic Modulation of Synaptic Transmission by Pregnenolone Sulfate as Studied by Optical Recordings

2005 ◽  
Vol 94 (6) ◽  
pp. 4131-4144 ◽  
Author(s):  
Ling Chen ◽  
Masahiro Sokabe
Keyword(s):  
Synaptic Transmission ◽  
Glutamate Release ◽  
Hippocampal Slices ◽  
Receptor Activation ◽  
Optical Recording ◽  
Perforant Path ◽  
Dependent Manner ◽  
Pregnenolone Sulfate ◽  
Voltage Sensitive Dyes ◽  
Dose Dependent

The effects of pregnenolone sulfate (PREGS), a putative neurosteroid, on the transmission of perforant path–granule cell synapses were investigated with an optical recording technique in rat hippocampal slices stained with voltage-sensitive dyes. Application of PREGS to the bath solution resulted in an acute augmentation of EPSP in a dose-dependent manner. The PREGS effect was dependent on the extracellular Ca2+ concentration ([Ca2+]o), but independent of NMDA receptor activation. PREGS caused a decrease in paired-pulse facilitation, which implies that PREGS positively modulates presynaptic neurotransmitter releases. Firmer support for this mechanism was that PREGS augmented the synaptically induced glial depolarization (SIGD) that reflects the activity of electrogenic glutamate transporters in glial cells during the uptake of released glutamate. The selective α7nAChR antagonist α-BGT or MLA prevented the SIGD increase by PREGS. Furthermore DMXB, a selective α7nAChR agonist, mimicked the PREGS effect on SIGD and antagonized the effect of PREGS. The presynaptic effect of PREGS was partially attenuated by the L-type Ca2+ channel (VGCC) blocker nifedipine. Based on these findings, we proposed a novel mechanism underlying the facilitated synaptic transmission by PREGS: this neurosteroid sensitizes presynaptic α7nAChR that is followed by an activation of L-type VGCC to increase the presynaptic glutamate release.

scholarly journals Mechanisms of L-Triiodothyronine-Induced Inhibition of Synaptosomal Na+-K+-ATPase Activity in Young Adult Rat Brain Cerebral Cortex

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Pradip K. Sarkar ◽  
Avijit Biswas ◽  
Arun K. Ray ◽  
Joseph V. Martin
Keyword(s):  
Cerebral Cortex ◽  
Atpase Activity ◽  
Adrenergic Receptor ◽  
Receptor Activation ◽  
Mammalian Brain ◽  
Neuronal Membrane ◽  
Dependent Manner ◽  
Adrenergic Agonist ◽  
Adult Rat ◽  
Dose Dependent

The role of thyroid hormones (TH) in the normal functioning of adult mammalian brain is unclear. Our studies have identified synaptosomal Na+-K+-ATPase as a TH-responsive physiological parameter in adult rat cerebral cortex. L-triiodothyronine (T3) and L-thyroxine (T4) both inhibited Na+-K+-ATPase activity (but not Mg2+-ATPase activity) in similar dose-dependent fashions, while other metabolites of TH were less effective. Although both T3and theβ-adrenergic agonist isoproterenol inhibited Na+-K+-ATPase activity in cerebrocortical synaptosomes in similar ways, theβ-adrenergic receptor blocker propranolol did not counteract the effect of T3. Instead, propranolol further inhibited Na+-K+-ATPase activity in a dose-dependent manner, suggesting that the effect of T3on synaptosomal Na+-K+-ATPase activity was independent ofβ-adrenergic receptor activation. The effect of T3on synaptosomal Na+-K+-ATPase activity was inhibited by theα2-adrenergic agonist clonidine and by glutamate. Notably, both clonidine and glutamate activateGi-proteins of the membrane second messenger system, suggesting a potential mechanism for the inhibition of the effects of TH. In this paper, we provide support for a nongenomic mechanism of action of TH in a neuronal membrane-related energy-linked process for signal transduction in the adult condition.

Adenosine inhibition of neutrophil damage during reperfusion does not involve KATP-channel activation

1997 ◽  
Vol 273 (4) ◽  
pp. H1677-H1687 ◽  
Author(s):  
Zhi-Qing Zhao ◽  
James C. Todd ◽  
Hiroki Sato ◽  
Xin-Liang Ma ◽  
J. Vinten-Johansen
Keyword(s):  
Infarct Size ◽  
Superoxide Radical ◽  
Receptor Activation ◽  
Polymorphonuclear Neutrophils ◽  
Vehicle Group ◽  
Myeloperoxidase Activity ◽  
Dependent Manner ◽  
Glucose Levels ◽  
Radical Generation ◽  
Dose Dependent

This study tests the hypothesis that cardioprotection exerted by adenosine A2-receptor activation and neutrophil-related events involves stimulation of ATP-sensitive potassium (KATP) channels on neutrophils during reperfusion. The adenosine A2 agonist CGS-21680 (CGS) inhibited superoxide radical generation from isolated rabbit polymorphonuclear neutrophils (PMNs) in a dose-dependent manner from 17.7 ± 2.1 to 7.4 ± 1.3 nmol/5 × 106 PMNs ( P < 0.05). Pinacidil, a KATP-channel opener, partially inhibited superoxide radical production, which was completely reversed by glibenclamide (Glib). Incremental doses of Glib in combination with CGS (1 μM) did not alter CGS-induced inhibition of superoxide radical generation. CGS significantly reduced PMN adherence to the endothelial surface of aortic segments in a dose-dependent manner from 189 ± 8 to 50 ± 6 PMNs/mm2( P < 0.05), which was also not altered by incremental doses of Glib. Infusion of CGS (0.025 mg/kg) before reperfusion reduced infarct size from 29 ± 2% in the Vehicle group to 15 ± 1% in rabbits undergoing 30 min of ischemia and 120 min of reperfusion ( P< 0.05). Glib (0.3 mg/kg) did not change the infarct size (28 ± 2%) vs. the Vehicle group and did not attenuate infarct size reduction by CGS (16 ± 1%). Glib did not change blood glucose levels. Cardiac myeloperoxidase activity was decreased in the ischemic tissue of the CGS group (0.15 ± 0.03 U/100 mg tissue) compared with the Vehicle group (0.37 ± 0.05 U/100 mg tissue; P < 0.05). We conclude that adenosine A2 activation before reperfusion partially reduces infarct size by inhibiting neutrophil activity and that this effect does not involve KATP-channel stimulation.

scholarly journals Emodin promotes apoptosis of human endometrial cancer through regulating the MAPK and PI3K/ AKT pathways

2019 ◽  
Vol 13 (1) ◽  
pp. 489-496 ◽  
Author(s):  
Jun Jiang ◽  
Nanyang Zhou ◽  
Pian Ying ◽  
Ting Zhang ◽  
Ruojia Liang ◽  
...  
Keyword(s):  
Endometrial Cancer ◽  
Signaling Pathways ◽  
Tumor Development ◽  
Mapk Signaling ◽  
Dependent Manner ◽  
Western Blot Assay ◽  
Anti Oxidant ◽  
Underlying Mechanisms ◽  
Induced Apoptosis ◽  
Dose Dependent

AbstractEmodin, a major component of rhubarb, has anti-tumor effects in a variety of cancers, influencing multiple steps of tumor development through modulating several signaling pathways. The aim of this study is to examine the effect of emodin on cell apoptosis and explore the underlying mechanisms in human endometrial cancer cells. Here we report that emodin can inhibit KLE cell proliferation and induce apoptosis in a time- and dose-dependent manner. Western blot assay found that emodin was involved in MAPK and PI3K/Akt signaling pathways. Specifically, emodin significantly suppressed the phosphorylation of AKT, and enhanced the phosphorylation of MAPK pathways. Furthermore, the generation of reactive oxygen species (ROS) was up-regulated in KLE cells upon treatment with emodin, while the anti-oxidant agent N-acetyl cysteine (NAC) can inhibit emodin-induced apoptosis and promote the activation of AKT and Bcl-2. Taken together, we revealed that emodin may induce apoptosis in KLE cells through regulating the PI3K/AKT and MAPK signaling pathways, indicating the importance of emodin as an anti-tumor agent.

scholarly journals Triterpenoid Saponin AG8 from Ardisia gigantifolia stapf. Induces Triple Negative Breast Cancer Cells Apoptosis through Oxidative Stress Pathway

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Li-Hua Mu ◽  
Li-Hua Wang ◽  
Teng-Fei Yu ◽  
Yu-Ning Wang ◽  
Hong Yan ◽  
...  
Keyword(s):  
Triple Negative ◽  
Growth Factor Receptor ◽  
Cell Types ◽  
Ros Generation ◽  
Triterpenoid Saponin ◽  
Dependent Manner ◽  
Breast Cancers ◽  
Underlying Mechanisms ◽  
Apoptotic Pathways ◽  
Dose Dependent

Triple-negative breast cancers (TNBCs) are associated with poor patient survival because of the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expressions. Our previous studies have shown that the triterpenoid saponin AG8 from Ardisia gigantifolia stapf. inhibits the proliferation of MDA-MB-231 cells. In this study, the effects of AG8 were further analyzed in different TNBC cell types: MDA-MB-231, BT-549, and MDA-MB-157 cells. AG8 inhibited the viability of MDA-MB-231, BT-549, and MDA-MB-157 cells in a dose-dependent manner and showed stronger cytotoxicity to African American (AA) and mesenchymal (M) subtypes than Caucasian (CA) and mesenchymal stem-like (MSL) subtypes, respectively. AG8 impaired the uptake of MitoTracker Red CMXRos by the mitochondria of TNBC cells in a dose-dependent manner, and this was recovered by N-acetyl-l-cysteine (NAC). AG8 affected GSH, SOD, and MDA levels of TNBC cells, but different TNBC subtypes had different sensitivities to AG8 and NAC. In addition, we found that AG8 increased the Bax/Bcl-2 ratio and the levels of cytoplasmic cytochrome c and significantly decreased phosphorylation of ERK and AKT in BT549 and MDA-MB-157 cells. AG8 elicited its anticancer effects through ROS generation, ERK and AKT activation, and by triggering mitochondrial apoptotic pathways in TNBC cells. AG8 had selective cytotoxic effects against the AA and M TNBC subtypes and markedly induced MDA-MB-157 (AA subtype) cell apoptosis through pathways that were not associated with ROS, which was different from the other two subtypes. The underlying mechanisms should be further investigated.

scholarly journals ROS-Induced GATA4 and GATA6 Downregulation Inhibits StAR Expression in LPS-Treated Porcine Granulosa-Lutein Cells

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Xiaolu Qu ◽  
Leyan Yan ◽  
Rihong Guo ◽  
Hui Li ◽  
Zhendan Shi
Keyword(s):  
Molecular Mechanisms ◽  
Cell Model ◽  
Animal Husbandry ◽  
Dependent Manner ◽  
Progesterone Production ◽  
Progesterone Synthesis ◽  
Porcine Granulosa Cell ◽  
Underlying Mechanisms ◽  
Dose Dependent

LPS is a major endotoxin produced by gram-negative bacteria, and exposure to it commonly occurs in animal husbandry. Previous studies have shown that LPS infection disturbs steroidogenesis, including progesterone production, and subsequently decreases animal reproductive performance. However, little information about the underlying mechanisms is available thus far. In the present study, an in vitro-luteinized porcine granulosa cell model was used to study the underlying molecular mechanisms of LPS treatment. We found that LPS significantly inhibits progesterone production and downregulates the expressions of progesterone synthesis-associated genes (StAR, CYP11A1, and 3β-HSD). Furthermore, the levels of ROS were significantly increased in an LPS dose-dependent manner. Moreover, transcriptional factors GATA4 and GATA6, but not NR5A1, were significantly downregulated. Elimination of LPS-stimulated ROS by melatonin or vitamin C could restore the expressions of GATA4, GATA6, and StAR. In parallel, StAR expression was also inhibited by the knockdown of GATA4 and GATA6. Based on these data, we conclude that LPS impairs StAR expression via the ROS-induced downregulation of GATA4 and GATA6. Collectively, these findings provide new insights into the understanding of reproductive losses in animals suffering from bacterial infection and LPS exposure.

scholarly journals Antioxidant and Antidiabetic Effect of Hibiscus rosasinensis Flower Extract on Streptozotocin Induced Experimental Rats-a Dose Response Study

2011 ◽  
Vol 3 (4) ◽  
pp. 13-21 ◽  
Author(s):  
Mirunalini SANKARAN ◽  
Arulmozhi VADIVEL
Keyword(s):  
Diabetic Rats ◽  
Antioxidant Effect ◽  
Dependent Manner ◽  
Enzymatic Antioxidants ◽  
Control Groups ◽  
Metabolizing Enzymes ◽  
Detailed Mechanism ◽  
Flower Extract ◽  
Dose Response Study ◽  
Dose Dependent

The present study was designed to evaluate the antidiabetic and antioxidant effect of Hibiscus rosasinensis against streptozotocin induced diabetic rats. Streptozotocin (STZ) was administered as a single dose (40 mg/kg) to induce diabetes. The hypoglycemic activity of Hibiscus rosasinensis extract (HRSEt) was investigated in a dose dependent manner such as (125, 250 and 500 mg/kg bwt) by evaluating various biochemical parameters. The levels of blood glucose, carbohydrate metabolizing enzymes, TBARS, enzymatic and non-enzymatic antioxidants and lipid profiles were found to be significantly increased in diabetic rats when compared to control groups. Administration of extract in the treated groups showed altered changes in the above mentioned parameters and found that among the three doseses, 250 mg/kg showed best result when compared to other two doses. HRSEt possess antioxidant, hypoglycemic and hypolipidemic activity against streptozotocin induced diabetic rats. However the detailed mechanism(s) of action will require elucidating in further studies.

scholarly journals Sargachromenol fromSargassum micracanthumInhibits the Lipopolysaccharide-Induced Production of Inflammatory Mediators in RAW 264.7 Macrophages

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Eun-Jin Yang ◽  
Young Min Ham ◽  
Kyong-Wol Yang ◽  
Nam Ho Lee ◽  
Chang-Gu Hyun
Keyword(s):  
Screening Program ◽  
Prostaglandin E ◽  
Raw 264.7 ◽  
Dependent Manner ◽  
Raw 264.7 Macrophages ◽  
Macrophage Cells ◽  
Raw 264.7 Macrophage Cells ◽  
Anti Inflammatory ◽  
Underlying Mechanisms ◽  
Dose Dependent

During our ongoing screening program designed to determine the anti-inflammatory potential of natural compounds, we isolated sargachromenol fromSargassum micracanthum. In the present study, we investigated the anti-inflammatory effects of sargachromenol on lipopolysaccharide (LPS)-induced inflammation in murine RAW 264.7 macrophage cells and the underlying mechanisms. Sargachromenol significantly inhibited the LPS-induced production of nitric oxide (NO) and prostaglandin E2(PGE2) in a dose-dependent manner. It also significantly inhibited the protein expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) in a dose-dependent manner in LPS-stimulated macrophage cells. Further analyses showed that sargachromenol decreased the cytoplasmic loss of inhibitorκBα(IκBα) protein. These results suggest that sargachromenol may exert its anti-inflammatory effects on LPS-stimulated macrophage cells by inhibiting the activation of the NF-κB signaling pathway. In conclusion, to our knowledge, this is the first study to show that sargachromenol isolated fromS. micracanthumhas an effective anti-inflammatory activity. Therefore, sargachromenol might be useful for cosmetic, food, or medical applications requiring anti-inflammatory properties.

scholarly journals Activation of the TCA Cycle to Provide Immune Protection in Zebrafish Immunized by High Magnesium-Prepared Vibrio alginolyticus Vaccine

2021 ◽  
Vol 12 ◽  
Author(s):  
Jun Yang ◽  
Xiao-li Yang ◽  
Yu-bin Su ◽  
Xuan-xian Peng ◽  
Hui Li
Keyword(s):  
Tca Cycle ◽  
Dependent Manner ◽  
High Concentration ◽  
Immune Genes ◽  
Bacterial Diseases ◽  
The Tca Cycle ◽  
Aquaculture Industry ◽  
Innate Immune Genes ◽  
Underlying Mechanisms ◽  
Dose Dependent

Vaccines are safe and efficient in controlling bacterial diseases in the aquaculture industry and are in line with green farming. The present study develops a previously unreported approach to prepare a live-attenuated V. alginolyticus vaccine by culturing bacteria in a high concentration of magnesium to attenuate bacterial virulence. Furthermore, metabolomes of zebrafish immunized with the live-attenuated vaccines were compared with those of survival and dying zebrafish infected by V. alginolyticus. The enhanced TCA cycle and increased fumarate were identified as the most key metabolic pathways and the crucial biomarker of vaccine-mediated and survival fish, respectively. Exogenous fumarate promoted expression of il1β, il8, il21, nf-κb, and lysozyme in a dose-dependent manner. Among the five innate immune genes, the elevated il1β, il8, and lysozyme are overlapped in the vaccine-immunized zebrafish and the survival from the infection. These findings highlight a way in development of vaccines and exploration of the underlying mechanisms.

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