scholarly journals Phenol sulphotransferase and uridine diphosphate glucuronyltransferase from rat liver in vivo and in vitro. 2,6-Dichloro-4-nitrophenol as selective inhibitor of sulphation

1977 ◽  
Vol 165 (3) ◽  
pp. 553-559 ◽  
Author(s):  
Gerard J. Mulder ◽  
Egbert Scholtens
Keyword(s):  
Rat Liver ◽  
Inhibitory Effect ◽  
Selective Inhibitor ◽  
Biological Processes ◽  
Uridine Diphosphate ◽  
Duration Of Action ◽  
Long Duration

Microsomal UDP-glucuronyltransferase and cytosolic sulphotransferase share many substrates, such as phenols and hydroxamic acids. In a search for a selective inhibitor of sulphation, several phenolic compounds were tested. 2,6-Dichloro-4-nitrophenol is introduced as a selective inhibitor of sulphation in vivo, having no effect on UDP-glucuronyltransferase activity. As substrate for both conjugating enzymes the phenolic drug harmol (7-hydroxy-1-methyl-9H-pyrido[3,4-b]indole) was used. In the rat in vivo 2,6-dichloro-4-nitrophenol caused almost complete inhibition of harmol sulphation after a single intraperitoneal injection (26μmol/kg) for 48h; the percentage of harmol sulphated decreased from 75% in controls to 5% in the treated rats. The percentage of harmol glucuronidated increased from 25 to 95%. Pentachlorophenol was equally effective but also highly toxic. Salicylamide had only a very-short-lasting inhibitory effect on sulphation. In vitro, 2,6-dichloro-4-nitrophenol inhibited sulphation of harmol by a rat liver postmitochondrial supernatant completely at 1μm, whereas even at 100μm it had no effect on glucuronidation of harmol. It is concluded that 2,6-dichloro-4-nitrophenol is a selective inhibitor of sulphation and, further, that its long duration of action makes it suitable for studies on the regulatory role of sulphation in some biological processes.

scholarly journals Activity of the Pore-Forming Virulence Factor Listeriolysin O Is Reversibly Inhibited by Naturally Occurring S-Glutathionylation

2017 ◽  
Vol 85 (4) ◽  
Author(s):  
Jonathan L. Portman ◽  
Qiongying Huang ◽  
Michelle L. Reniere ◽  
Anthony T. Iavarone ◽  
Daniel A. Portnoy
Keyword(s):  
Protein Function ◽  
Inhibitory Effect ◽  
Cysteine Residue ◽  
Infection Model ◽  
Listeriolysin O ◽  
Content Type ◽  
Pore Forming Proteins

ABSTRACT Cholesterol-dependent cytolysins (CDCs) represent a family of homologous pore-forming proteins secreted by many Gram-positive bacterial pathogens. CDCs mediate membrane binding partly through a conserved C-terminal undecapeptide, which contains a single cysteine residue. While mutational changes to other residues in the undecapeptide typically have severe effects, mutation of the cysteine residue to alanine has minor effects on overall protein function. Thus, the role of this highly conserved reactive cysteine residue remains largely unknown. We report here that the CDC listeriolysin O (LLO), secreted by the facultative intracellular pathogen Listeria monocytogenes, was posttranslationally modified by S-glutathionylation at this conserved cysteine residue and that either endogenously synthesized or exogenously added glutathione was sufficient to form this modification. When recapitulated with purified protein in vitro, this modification completely ablated the activity of LLO, and this inhibitory effect was fully reversible by treatment with reducing agents. A cysteine-to-alanine mutation in LLO rendered the protein completely resistant to inactivation by S-glutathionylation, and a mutant expressing this mutation retained full hemolytic activity. A mutant strain of L. monocytogenes expressing the cysteine-to-alanine variant of LLO was able to infect and replicate within bone marrow-derived macrophages indistinguishably from the wild type in vitro, yet it was attenuated 4- to 6-fold in a competitive murine infection model in vivo. This study suggests that S-glutathionylation may represent a mechanism by which CDC-family proteins are posttranslationally modified and regulated and help explain an evolutionary pressure to retain the highly conserved undecapeptide cysteine.

Role of endothelial cells in regulating hemoglobin-induced changes in lymphatic pumping

1992 ◽  
Vol 263 (6) ◽  
pp. H1880-H1887 ◽  
Author(s):  
R. M. Elias ◽  
J. Eisenhoffer ◽  
M. G. Johnston
Keyword(s):  
Endothelial Cells ◽  
Smooth Muscle ◽  
Inhibitory Effect ◽  
Direct Inhibitory Effect ◽  
Induced Changes ◽  
Lymphatic Pumping ◽  
Pumping Activity

Studies with a sheep isolated duct preparation in vivo demonstrated that the route of administration of hemoglobin was important in demonstrating its inhibitory effect on lymphatic pumping. With autologous oxyhemoglobin administered intravenously (final plasma concentration 5 x 10(-5) M), pumping was not inhibited. However, the addition of oxyhemoglobin (5 x 10(-5) M) into the reservoir (lumen of the duct) resulted in > 95% inhibition of pumping. The extraluminal administration of oxyhemoglobin (10(-5) M) to bovine mesenteric lymphatics in vitro resulted in a 40% inhibition of pumping, whereas the introduction of oxyhemoglobin (10(-5) M) into the lumen of the vessels suppressed pumping 95%. In vessels mechanically denuded of endothelium, intraluminal oxyhemoglobin inhibited pumping 50%. These results suggested that oxyhemoglobin depressed pumping through an effect on both smooth muscle and endothelium. Once pumping was inhibited with oxyhemoglobin administration, stimulation of the duct with elevations in transmural pressure restored pumping activity when endothelial cells were present. However, in the absence of endothelium, pumping decreased with increases in distending pressures. We conclude that oxyhemoglobin has a direct inhibitory effect on lymphatic smooth muscle. The ability of oxyhemoglobin to alter the pressure range over which the lymph pump operates appears to be dependent on an intact endothelium.

scholarly journals LINC01006 facilitates cell proliferation, migration and invasion in prostate cancer through targeting miR-34a-5p to up-regulate DAAM1

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Enhui Ma ◽  
Qianqian Wang ◽  
Jinhua Li ◽  
Xinqi Zhang ◽  
Zhenjia Guo ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Prostate Gland ◽  
Inhibitory Effect ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Protein Coding ◽  
Novel Target

Abstract Background Prostate cancer (PCa) is a kind of malignancy occurring in the prostate gland. Substantial researches have proved the major role of long noncoding RNAs (lncRNAs) in PCa. However, the role of long intergenic non-protein coding RNA 1006 (LINC01006) in PCa has not been investigated yet. Methods RT-qPCR was used to examine the expression levels of LINC01006 and its downstream targets. The function of LINC01006 in PCa was tested by in vitro and in vivo assays. With application of RNA pull down, RNA immunoprecipitation (RIP) and luciferase reporter assays, the interaction among LINC01006, miR-34a-5p and disheveled associated activator of morphogenesis 1 (DAAM1) were verified. Results LINC01006 expression presented high in PCa cell lines. LINC01006 silencing suppressed cell proliferative, migratory, invasive capacities while accelerated apoptotic rate. Besides, LINC01006 knockdown also suppressed tumor growth and metastasis in vivo. Furthermore, miR-34a-5p, a tumor suppressor in PCa, was sponged by LINC01006. Moreover, DAAM1 was targeted by miR-34a-5p and promoted PCa progression. More intriguingly, rescue assays suggested that the inhibitory effect of LINC01006 knockdown on PCa development was offset by DAAM1 overexpression. Conclusions LINC01006 promoted PCa progression by sponging miR-34a-5p to up-regulate DAAM1, providing a novel target for PCa therapy.

Inhibitory Effect of Resveratrol on the Pharmacokinetics of Ticagrelor in Vivo and Vitro

2021 ◽  
Author(s):  
Peng Wang ◽  
Xiao-Xia Hu ◽  
Ying-hui Li ◽  
Nan-Yong Gao ◽  
Guo-quan Chen ◽  
...  
Keyword(s):  
Rat Liver ◽  
Liver Microsomes ◽  
In Vitro Study ◽  
Inhibitory Effect ◽  
Control Group ◽  
Rat Liver Microsomes ◽  
Sprague Dawley ◽  
Group B

This study was to evaluate the effect of resveratrol on the pharmacokinetics of ticagrelor in rats and the metabolism of ticagrelor in human CYP3A4 and liver microsomes. Eighteen Sprague-Dawley rats were randomly divided into three groups: group A (control group), group B (50mg/kg resveratrol), and group C (150mg/kg resveratrol ). After 30 minutes administration of resveratrol, a single dose of ticagrelor (18mg/kg) was administered orally. The vitro experiment was performed to examine the influence of resveratrol on ticagrelor metabolism in CYP3A4*1, human, and rat liver microsomes. Serial biological samples were assayed by validated UHPLC-MS/MS methods. In vivo study, the AUC and Cmax of ticagrelor in group B and C appeared to be significantly higher than the control group, while Vz/F and CLz/F of ticagrelor in group B and C were significantly decreased. In vitro study, resveratrol exhibited an inhibitory effect on CYP3A4*1, human and rat liver microsomes. The IC50 values of resveratrol were 56.75μM，69.07μM and 14.22μM, respectively. Our results indicated that resveratrol had a inhibitory effect on the metabolism of ticagrelor in vitro and vivo. It should be paid more attention to the clinical combination of resveratrol with ticagrelor and ticagrelor plasma concentration should be monitored to avoid the occurrence of adverse reaction.

The Role of the Microsomal Membrane in Control of Uridine Diphosphate Glucuronyltransferase Activity in vitro and in vivo

1974 ◽  
Vol 2 (6) ◽  
pp. 1167-1172 ◽  
Author(s):  
A. B. GRAHAM ◽  
D. T. PECHEY ◽  
G. C. WOOD ◽  
B. G. WOODCOCK
Keyword(s):  
Microsomal Membrane ◽  
Uridine Diphosphate

scholarly journals In vitro inhibition of porcine cytochrome P450 by 17β-estradiol and 17α-estradiol

2011 ◽  
Vol 4 (2) ◽  
pp. 78-84 ◽  
Author(s):  
Galia Zamaratskaia ◽  
Martin Rasmussen ◽  
Isabelle Herbin ◽  
Bo Ekstrand ◽  
Vladimir Zlabek
Keyword(s):  
Cytochrome P450 ◽  
Inhibitory Effect ◽  
17Β Estradiol ◽  
Cyp2e1 Activity ◽  
High Concentrations ◽  
Testicular Steroids ◽  
Sexually Mature

In vitro inhibition of porcine cytochrome P450 by 17β-estradiol and 17α-estradiol Sexually mature pigs are known to possess high concentrations of testicular steroids, which have been shown to change the activities of cytochrome P450 in vitro. The aim of the present study was to evaluate the regulation of CYP1A and CYP2E1 activity by the steroids dihydrotestosterone (DHT), 3β-androstenol, 17β-estradiol and 17α-estradiol. Catalytic activities of 7-ethoxyresorufin O-deethylase (EROD) and 7-methoxyresorufin O-demethylase (MROD) were used as markers of CYP1A activities, while p-nitrophenol hydroxylase (PNPH) was used as a marker of CYP2E1 activities. Of the steroids tested, only 17β-estradiol and 17α-estradiol inhibited EROD and MROD activities. This inhibition was observed when a steroid concentration of 100 μM was used, while lower concentrations showed no inhibitory effect. PNPH activities were inhibited only by 100 μM of 17β-estradiol. The significance of these results in vivo is unknown because inhibition was only found when concentrations of estrogens higher than physiological levels were used. Nevertheless, the results provided further evidence on the important role of estrogens in regulation of porcine cytochrome P450 activities.

scholarly journals Inhibiting IL-6 During Cytokine Storm in COVID-19: Potential Role of Natural Products

2021 ◽  
Author(s):  
Amirreza Nasirzadeh ◽  
Mohammad hosein Jafarzadeh Maivan ◽  
Javad Bazeli ◽  
Jafar Hajavi ◽  
Negar Yavarmanesh ◽  
...  
Keyword(s):  
Natural Products ◽  
Medicinal Plants ◽  
Inflammatory Responses ◽  
Survival Rates ◽  
Inhibitory Effect ◽  
Cytokine Storm ◽  
Regulatory Effects

Plant species with anti-inflammatory properties might play an essential role in combatting COVID-19 via reducing cytokine storms. We aimed to review the extant evidence of the potential therapeutic efficacy of natural products against cytokine storms by inhibiting interleukin-6 (IL-6) as a major pathological mediator. Data were collected following an electronic search in major databases (Pubmed, Scopus, Web of Science, Google Scholar) and also preprint articles on preprint and medRxiv servers by using a combination of relevant keywords. Seventeen active compounds and medicinal plants were found and reviewed in the present review. Results of both in-vivo and in-vitro experiments conducted on these compounds showed that Phillyrin, SMFM, Qiangzhi decoction, curcumin, Shen-Fu, Forsythia, and Alpha-Mangostin inhibit the production of IL-6. Andrographolide and Liu Shen Wan have an inhibitory effect on releasing this agent, while Ilex Asprella and Deoxy-11,12-didehydroandrographolide and naringin reduce the expression of IL-6. Theaflavin and Cholorogenic acid inhibit the secretion of IL-6, Xuebijing, and Chai-Hu-Gui-Zi-Gan-Jiang-Tang and Lipanpaidu prescription can reduce the serum level of IL-6. These agents also effectively improve infected lungs, increase survival rates, and minimize tissue damage. Medicinal plants and their phytochemical ingredients with down-regulatory effects on the expression of IL-6 have a potential influence on the inhibition of cytokine storms during viral infection caused by COVID-19. Therefore, phytochemicals could be regarded as promising candidates for managing cytokine storm inflammatory responses due to COVID-19 infection.

scholarly journals Dronerarone Acts as a Selective Inhibitor of 3,5,3′-Triiodothyronine Binding to Thyroid Hormone Receptor-α1: In Vitro and in Vivo Evidence

Endocrinology ◽  
2003 ◽  
Vol 144 (2) ◽  
pp. 552-558 ◽  
Author(s):  
H. C. van Beeren ◽  
W. M. C. Jong ◽  
E. Kaptein ◽  
T. J. Visser ◽  
O. Bakker ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Hormone Receptor ◽  
Thyroid Hormone Receptor ◽  
Density Lipoprotein ◽  
Inhibitory Effect ◽  
Selective Inhibitor ◽  
Receptor Protein ◽  
Qtc Interval

Dronedarone (Dron), without iodine, was developed as an alternative to the iodine-containing antiarrhythmic drug amiodarone (AM). AM acts, via its major metabolite desethylamiodarone, in vitro and in vivo as a thyroid hormone receptor α1 (TRα1) and TRβ1 antagonist. Here we investigate whether Dron and/or its metabolite debutyldronedarone inhibit T3 binding to TRα1 and TRβ1in vitro and whether dronedarone behaves similarly to amiodarone in vivo. In vitro , Dron had a inhibitory effect of 14% on the binding of T3 to TRα1, but not on TRβ1. Desethylamiodarone inhibited T3 binding to TRα1 and TRβ1 equally. Debutyldronedarone inhibited T3 binding to TRα1 by 77%, but to TRβ1 by only 25%. In vivo , AM increased plasma TSH and rT3, and decreased T3. Dron decreased T4 and T3, rT3 did not change, and TSH fell slightly. Plasma total cholesterol was increased by AM, but remained unchanged in Dron-treated animals. TRβ1-dependent liver low density lipoprotein receptor protein and type 1 deiodinase activities decreased in AM-treated, but not in Dron-treated, animals. TRα1-mediated lengthening of the QTc interval was present in both AM- and Dron-treated animals. The in vitro and in vivo findings suggest that dronedarone via its metabolite debutyldronedarone acts as a TRα1-selective inhibitor.

scholarly journals Exaggerated inflammation, impaired host defense, and neuropathology in progranulin-deficient mice

2009 ◽  
Vol 207 (1) ◽  
pp. 117-128 ◽  
Author(s):  
Fangfang Yin ◽  
Rebecca Banerjee ◽  
Bobby Thomas ◽  
Ping Zhou ◽  
Liping Qian ◽  
...  
Keyword(s):  
Host Defense ◽  
Hippocampal Slices ◽  
Interleukin 10 ◽  
Biological Processes ◽  
Listeria Monocytogenes Infection ◽  
The Brain ◽  
Deficient Mice

Progranulin (PGRN) is a widely expressed protein involved in diverse biological processes. Haploinsufficiency of PGRN in the human causes tau-negative, ubiquitin-positive frontotemporal dementia (FTD). However, the mechanisms are unknown. To explore the role of PGRN in vivo, we generated PGRN-deficient mice. Macrophages from these mice released less interleukin-10 and more inflammatory cytokines than wild type (WT) when exposed to bacterial lipopolysaccharide. PGRN-deficient mice failed to clear Listeria monocytogenes infection as quickly as WT and allowed bacteria to proliferate in the brain, with correspondingly greater inflammation than in WT. PGRN-deficient macrophages and microglia were cytotoxic to hippocampal cells in vitro, and PGRN-deficient hippocampal slices were hypersusceptible to deprivation of oxygen and glucose. With age, brains of PGRN-deficient mice displayed greater activation of microglia and astrocytes than WT, and their hippocampal and thalamic neurons accumulated cytosolic phosphorylated transactivation response element DNA binding protein–43. Thus, PGRN is a key regulator of inflammation and plays critical roles in both host defense and neuronal integrity. FTD associated with PGRN insufficiency may result from many years of reduced neutrotrophic support together with cumulative damage in association with dysregulated inflammation.

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