scholarly journals Effects of a thyromimetic on apolipoprotein B-100 in rats

2000 ◽  
Vol 25 (3) ◽  
pp. 299-308 ◽  
Author(s):  
Y Wada ◽  
S Matsubara ◽  
J Dufresne ◽  
GM Hargrove ◽  
ZF Stephan ◽  
...  
Keyword(s):  
Apolipoprotein B ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Mrna Editing ◽  
Human Hepatoma Cells ◽  
Apo B ◽  
Editing Activity ◽  
Cardiac Sparing ◽  
Dose Dependent

We have studied the effects of a cardiac sparing thyromimetic, CGS 23425, on postprandial levels of triglycerides, abundance of apolipoprotein B (apo B) protein and hepatic apo B mRNA expression in rats. When compared with control rats, triglyceride clearance was significantly accelerated by treatment with CGS 23425. A full return to baseline values was achieved within 8 h after ingesting a large quantity of fat, as compared to >24 h in control animals. The abundance of apo B-100 protein in CGS 23425-treated hyperlipidemic rats decreased in a dose-dependent manner, but levels of apo B-48 were not significantly affected. Like L-tri-iodothyronine (L-T(3)), treatment with 30 microg/kg CGS 23425 for 6 or 9 days decreased the levels of apo B-100 protein by 80% and 40% respectively. This change was paralleled by a 27% reduction in hepatic apo B-100 mRNA. To investigate a potential mechanism of CGS 23425 action, we measured in vitro apo B mRNA editing activity in hepatocellular extract from control or CGS 23425-treated rats. Treatment with CGS 23425 increased activity of the hepatic apo B-100 editosome, apobec-1. In human hepatoma cells which lack apobec-1 activity, apo B-100 mRNA levels remained the same in cells treated with or without the agent. In summary, these observations show that CGS 23425 decreases the levels of apo B-100 in rats. This action of CGS 23425 involves apo B-100 mRNA editing activity.

scholarly journals A Novel Mechanism in Regulating the Alpha-Subunit of the Epithelial Sodium Channel (α ENaC) by the Alternatively Spliced Form α ENaC-b

2009 ◽  
Vol 2 ◽  
pp. BCI.S880 ◽  
Author(s):  
Marlene F. Shehata
Keyword(s):  
Sodium Channel ◽  
Epithelial Sodium Channel ◽  
Dominant Negative Effect ◽  
Kidney Cortex ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Rt Pcr ◽  
Alternatively Spliced ◽  
Dose Dependent

Introduction In Dahl rats’ kidney cortex, the alternatively spliced form of the epithelial sodium channel α subunit (α ENaC-b) is the most abundant mRNA transcript (32+/-3 fold > α ENaC-wt) as was investigated by quantitative RT-PCR analysis. α ENaC-b mRNA levels were significantly higher in Dahl R versus S rats, and were further augmented by high salt diet. Objectives In the present study, we described the molecular cloning and searched for a possible role of α ENaC-b by testing its potential expression in COS7 cells as well as its impact on α ENaC-wt expression levels when co-expressed in COS7 cells in a dose-dependent manner. Methods Using RT-PCR strategy, the full-length wildtype α ENaC transcript and the alternatively spliced form α ENaC-b were amplified, sequenced, cloned, subcloned into PCMV-sport6 expression vector, expressed and co-expressed into COS7 cells in a dose-dependent manner. A combination of denaturing and native western blotting techniques was employed to examine the expression of α ENaC-b in vitro, and to determine if an interaction between α ENaC-b and α ENaC-wt occurs in vitro, and finally to demonstrate if degradation of α ENaC-wt protein does occur. Results α ENaC-b is translated in COS7 cells. Co-expression of α ENaC-b together with α ENaC-wt reduced α ENaC-wt levels in a dose-dependent manner. α ENaC-wt and α ENaC-b appear to form a complex that enhances the degradation of α ENaC-wt. Conclusions Western blots suggest a novel mechanism in α ENaC regulation whereby α ENaC-b exerts a dominant negative effect on α ENaC-wt expression. This is potentially by sequestering α ENaC-wt, enhancing its proteolytic degradation, and possibly explaining the mechanism of salt-resistance in Dahl R rats.

scholarly journals Potential Mechanisms of an Antiadenomyosis Chinese Herbal Formula Shaoyao-Gancao Decoction in Primary Cell Culture Model

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Yong-Ge Guan ◽  
Jin-Bin Liao ◽  
Kun-Yin Li ◽  
Yu-Cui Li ◽  
Yang Song ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Culture Model ◽  
Proliferation And Apoptosis ◽  
Medicine Prescription ◽  
Chinese Medicine Prescription ◽  
Induced Apoptosis ◽  
Dose Dependent

Background. Shaoyao-Gancao Decoction (SGD), a well-known traditional Chinese medicine prescription, has been widely used to treat adenomyosis, dysmenorrhea, abdominal pain, and inflammation in Asia. However, the mechanism underlying the effectiveness of SGD in the treatment of adenomyosis still remains elusive. The present study aimed to investigate the bioactivity of SGD and its underlying molecular mechanisms using cultured human adenomyosis-derived cells.Methods. Human adenomyosis-derived cells were treated with SGD and its major constituents (paeoniflorin and liquiritin)in vitro. Effects of SGD, paeoniflorin, and liquiritin on cell proliferation and apoptosis were examined by MTT assay and flow cytometry analyses. The effects of SGD, paeoniflorin, and liquiritin on the production of PGE2and PGF2αwere assayed using ELISA. ER-αand OTR mRNA expression levels were also evaluated by real-time qRT-PCR.Results. SGD, paeoniflorin, and liquiritin inhibited proliferation and induced apoptosis of human adenomyosis-derived cells in a dose-dependent manner. SGD and paeoniflorin significantly reduced the PGE2and PGF2αproduction. Furthermore, they remarkably decreased the mRNA levels of ER-αand OTR.Conclusions. The results of this study provide possible mechanisms for the bioactivity of SGD for treating adenomyosis and contribute to the ethnopharmacological knowledge about this prescription.

scholarly journals Evaluation of in Vitro Bio-Activities Effects of WST (Wushanshencha)

2019 ◽  
Vol 9 (7) ◽  
pp. 1325 ◽  
Author(s):  
Chong Li ◽  
Chaomin Liu ◽  
Jing Zhang ◽  
Honggang Li ◽  
Yan Zhou ◽  
...  
Keyword(s):  
Hepg2 Cells ◽  
Mutagenic Effect ◽  
High Dose ◽  
Dependent Manner ◽  
Human Hepatoma Cells ◽  
Related Factors ◽  
Anti Cancer ◽  
Functional Components ◽  
Dose Dependent

As a traditional Chinese drink, tea is favored for its rich flavor and its medicinal functionality. In this study, the in vitro bioactivities of Wushanshencha (WST; a local tea from Chongqing, China), which is processed mainly from the leaves of the wild Malus hupehensis (Pamp.) Rehd.). We assessed the scavenging capacity of tea extracts on 1, 1-diphenyl-2-picrylhydrazyl (DPPH); 2, 2′-azino-bis (3-ethylbenzthiazoline-6- sulphonic acid) diammonium salt (ABTS); and hydroxyl (OH) free radicals, and demonstrate the high antioxidant activity and dose-dependent relationship of these extracts. We also detail the anti-mutagenic effect of these tea extracts against the Salmonella typhimurium TA98 strain induced by the 2, 7-diaminofluorene (2, 7-AF) mutagen and the TA100 strain induced by the N-methyl-N′-nitro- N- nitrosoguanidine (MNNG) mutagen at concentrations of 1.25 and 2.50 mg/plate, respectively, with the high-dose groups showing better results. We investigated the anticancer mechanisms of WST extracts (40, 100, and 160 μg/mL) in HepG2 human hepatoma cells via 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay and quantitative real-time reverse transcription-polymerase chain reaction (RT-qPCR). The results showed that the proliferation of HepG2 cells was significantly inhibited in a dose-dependent manner by the tea extracts. Moreover, apoptosis in HepG2 cells was induced via upregulation of Caspase-3, Caspase-7, Caspase-8, Caspase-9, p21, p53, and Bax as well as downregulation of Bcl-2 apoptosis-associated factors, as assessed via mRNA expression levels after treating with WST extracts. The expression of inflammation-related factors, e.g., NF-κB, and Cox-2, was significantly downregulated by the WST extracts, demonstrating its inflammatory properties. Together, these observations indicated that WST extracts have anti-inflammatory and anti-cancer properties. In addition, high-performance liquid chromatography (HPLC) analysis showed that WST extracts contained chlorogenic acid, 4-hydroxycinnamic acid, isoquercitrin, taxifolin, quercitrin, rosmarinic acid, myricetin, baicalin, neosperidin dihydrochalcone, and quercetin. As such, WST appears to be an effectively functional drink, due to its rich functional components and anti-cancer activity.

Neopterin-induced Suppression of Erythropoietin Production In Vitro

Pteridines ◽  
1995 ◽  
Vol 6 (1) ◽  
pp. 12-16 ◽  
Author(s):  
W. Schobersberger ◽  
W. Jelkmann ◽  
J. Fandrey ◽  
S. Frede ◽  
H. Wachter ◽  
...  
Keyword(s):  
Inhibitory Effect ◽  
Inhibitory Influence ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Anemia Of Chronic Disease ◽  
Erythropoietin Production ◽  
High Concentrations ◽  
Dose Dependent

Summary The production of neopterin increases in several diseases with activation of the ceIlular immune response. As previously shown serum concentrations of neopterin are inversely correlated with blood hemoglobin concentrations in the anemia of hematological and malignant disorders. Besides the role of chronic immune activation on the disturbed iron metabolism, an inhibitory influence of pteridines on cellular erythropoietin production could not be excluded. To test the possibility that pteridines are able to suppress the hypoxia-induced production of erythropoietin, the effects of neopterin and 7,8-dihydroneopterin on the human ceIl line HepG2 (hepatoceIlular carcinoma) were investigated. 24 h incubation with neopterin induced a dose-dependent reduction of erythropoietin production. The erythropoietin concentration significantly decreased by - 57.6% with 300 11M and by - 34.9% with 100 11M neopterin, respectively. 7,8 dihydroneopterin did not influence erythropoietin production. The inhibitory effect of neopterin on erythropoietin production was a consequence of reduced erythropoietin-mRNA levels. The results of this study show a neopterin-induced suppression of hypoxia-induced erythropoietin formation in HepG2 cultures in a dose dependent manner. We speculate that under in vivo conditions high concentrations of neopterin can aggravate the anemia of chronic disease.

Oncotic pressure regulates gene transcriptions of albumin and apolipoprotein B in cultured rat hepatoma cells

1992 ◽  
Vol 263 (2) ◽  
pp. C397-C404 ◽  
Author(s):  
A. Yamauchi ◽  
Y. Fukuhara ◽  
S. Yamamoto ◽  
F. Yano ◽  
M. Takenaka ◽  
...  
Keyword(s):  
Apolipoprotein B ◽  
Protein S ◽  
Hepatoma Cells ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Oncotic Pressure ◽  
Regulation Of Expression ◽  
Apo B ◽  
Albumin Mrna ◽  
Rat Hepatoma

The mechanism of the accelerated syntheses of albumin and apolipoprotein B (apo B) in response to decreased oncotic pressure was investigated in cultured rat hepatoma H4-II-E cells. Addition of dextran (mol wt 6-9 x 10(4)) to the culture medium decreased the levels of albumin and apo B mRNAs in an oncotic pressure-dependent manner. The reductions of both mRNAs were attenuated with increase in the molecular weight of dextran, which resulted in a decrease in oncotic pressure. Addition of macromolecule increased the viscosity in medium; however, alteration of viscosity appeared not to correlate with albumin and apo B mRNA levels. Transcriptional run-on assays with isolated nuclei from dextran-treated vs. untreated hepatoma cells indicated that the changes in steady-state mRNA levels were mainly controlled at the transcriptional step. Treatment with cycloheximide increased albumin mRNA to the basal level, which was effectively suppressed by dextran, and resulted in superinduction of apo B mRNA. These changes occurred primarily at the transcriptional step. These results suggest that regulations of the expressions of the albumin and apo B genes for adaptive increases in the mRNAs may require the continued synthesis of a labile protein(s) or a limiting transcription factor(s). We conclude that oncotic pressure plays an important role in regulation of expression of the albumin and apo B genes at the transcriptional step.

Oxygenation of 18-hydroxycorticosterone as the final reaction for aldosterone biosynthesis

1984 ◽  
Vol 107 (3) ◽  
pp. 395-400 ◽  
Author(s):  
Itaru Kojima ◽  
Etsuro Ogata ◽  
Hiroshi Inano ◽  
Bun-ichi Tamaoki
Keyword(s):  
Carbon Monoxide ◽  
Hydroxysteroid Dehydrogenase ◽  
Dependent Manner ◽  
In Vitro Production ◽  
Mitochondrial Preparation ◽  
Final Reaction ◽  
Vitro Production ◽  
Dose Dependent ◽  
Cytochrome P 450

Abstract. Incubation of 18-hydroxycorticosterone with the sonicated mitochondrial preparation of bovine adrenal glomerulosa tissue leads to the production of aldosterone, as measured by radioimmunoassay. The in vitro production of aldosterone from 18-hydroxycorticosterone requires both molecular oxygen and NADPH, and is inhibited by carbon monoxide. Cytochrome P-450 inhibitors such as metyrapone, SU 8000. SU 10603, SKF 525A, amphenone B and spironolactone decrease the biosynthesis of aldosterone from 18-hydroxycorticosterone. These results support the conclusion that the final reaction in aldosterone synthesis from 18-hydroxycorticosterone is catalyzed by an oxygenase, but not by 18-hydroxysteroid dehydrogenase. By the same preparation, the production of [3H]aldosterone but not [3H]18-hydroxycorticosterone from [1,2-3H ]corticosterone is decreased in a dose-dependent manner by addition of non-radioactive 18-hydroxycorticosterone.

Appraisal of Immunological Impacts of Melaleuca leucadendra Extract over Macrophage Performance in Vitro

2020 ◽  
Keyword(s):  
Nitric Oxide ◽  
Interleukin 2 ◽  
Dependent Manner ◽  
Reduced Pressure ◽  
Medical Plant ◽  
Dose Dependent ◽  
Level Production ◽  
Melaleuca Leucadendra ◽  
Phagocytic Killing

This trial research was performed to discuss the immune-influence of Melaleuca leucadendra ‘paper-bark tree’ dried leaves which is an important medical plant known in many regions in the world. The leaves were dissolved in a mixture of (ethanol + water) (3:1) mixture, then filtered, evaporated and dried under reduced pressure to obtain leaves extract. The macrophages of blood derived origin were provided from rats and mixed with three different leaves extracts doses in tissue culture plates and incubated then stained with fluorescent acridine orange and examined under fluorescent microscope to assess the phagocytic and killing potency. The wells contents were aspirated and assayed for nitric oxide and interleukin-2 levels. The results displayed an obvious increase in phagocytic, killing performance as well as nitric oxide and IL-2 level production than control in a dose dependent manner. The obtained results suggested the immune-stimulant impact of the paper-bark tree leaves.

Serotonin elicits long-lasting enhancement of rhythmic respiratory activity in turtle brain stems in vitro

2001 ◽  
Vol 91 (6) ◽  
pp. 2703-2712 ◽  
Author(s):  
Stephen M. Johnson ◽  
Julia E. R. Wilkerson ◽  
Daniel R. Henderson ◽  
Michael R. Wenninger ◽  
Gordon S. Mitchell
Keyword(s):  
Brain Stem ◽  
Respiratory Activity ◽  
Dependent Manner ◽  
Frequency Increase ◽  
Burst Frequency ◽  
Bath Application ◽  
Burst Amplitude ◽  
Dose Dependent ◽  
The Brain

Brain stem preparations from adult turtles were used to determine how bath-applied serotonin (5-HT) alters respiration-related hypoglossal activity in a mature vertebrate. 5-HT (5–20 μM) reversibly decreased integrated burst amplitude by ∼45% ( P < 0.05); burst frequency decreased in a dose-dependent manner with 20 μM abolishing bursts in 9 of 13 preparations ( P < 0.05). These 5-HT-dependent effects were mimicked by application of a 5-HT1A agonist, but not a 5-HT1B agonist, and were abolished by the broad-spectrum 5-HT antagonist, methiothepin. During 5-HT (20 μM) washout, frequency rebounded to levels above the original baseline for 40 min ( P < 0.05) and remained above baseline for 2 h. A 5-HT3 antagonist (tropesitron) blocked the post-5-HT rebound and persistent frequency increase. A 5-HT3 agonist (phenylbiguanide) increased frequency during and after bath application ( P < 0.05). When phenylbiguanide was applied to the brain stem of brain stem/spinal cord preparations, there was a persistent frequency increase ( P < 0.05), but neither spinal-expiratory nor -inspiratory burst amplitude were altered. The 5-HT3receptor-dependent persistent frequency increase represents a unique model of plasticity in vertebrate rhythm generation.

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