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 Article Commentary: The Alternatively Spliced Form “b” of the Epithelial Sodium Channel α subunit (α ENaC): Any Prior Evidence of its Existence?

2010 ◽  
Vol 4 ◽  
pp. CMC.S5270
Author(s):  
Marlene F. Shehata
Keyword(s):  
Sodium Channel ◽  
Mrna Expression ◽  
Epithelial Sodium Channel ◽  
Protein Band ◽  
Sodium Balance ◽  
Kidney Cortex ◽  
Western Blots ◽  
Α Subunit ◽  
Alternatively Spliced ◽  
Additional Protein

The epithelial sodium channel (ENaC) is critical in maintaining sodium balance across aldosterone-responsive epithelia. ENaC is a combined channel formed of three subunits (αβγ) with α ENaC subunit being the most critical for channel functionality. In a previous report, we have demonstrated the existence and mRNA expression levels of four alternatively spliced forms of the α ENaC subunit denoted by -a, -b, -c and -d in kidney cortex of Dahl S and R rats. Of the four alternatively spliced forms presently identified, α ENaC-b is considered the most interesting for the following reasons: Aside from being a salt-sensitive transcript, α ENaC-b mRNA expression is ~32 fold higher than α ENaC wildtype in kidney cortex of Dahl rats. Additionally, the splice site used to generate α ENaC-b is conserved across species. Finally, α ENaC-b mRNA expression is significantly higher in salt-resistant Dahl R rats versus salt-sensitive Dahl S rats. As such, this commentary aims to highlight some of the previously published research articles that described the existence of an additional protein band on α ENaC western blots that could account for α ENaC-b in other rat species.

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 Effects of polychlorinated biphenyl (Aroclor 1254) on steroidogenesis and antioxidant system in cultured adult rat Leydig cells

2007 ◽  
Vol 192 (2) ◽  
pp. 325-338 ◽  
Author(s):  
Palaniappan Murugesan ◽  
Muthusamy Balaganesh ◽  
Karundevi Balasubramanian ◽  
Jagadeesan Arunakaran
Keyword(s):  
Antioxidant System ◽  
Leydig Cells ◽  
Hydroxysteroid Dehydrogenase ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Rt Pcr ◽  
Steroidogenic Enzymes ◽  
Aroclor 1254 ◽  
Nonenzymatic Antioxidants ◽  
Dose Dependent

Polychlorinated biphenyls (PCBs) are ubiquitous and persistent environmental contaminants that disturb normal endocrine functions, including gonadal functions in humans and mammals. In the present study, we examined the direct effects of PCB on rat Leydig cells in vitro. Adult Leydig cells were purified by Percoll gradient centrifugation method and the purity of Leydig cells was also determined by 3β-hydroxysteroid dehydrogenase (3β-HSD) staining method. Purified Leydig cells were exposed to different concentrations (10− 10–10− 7 M) of PCB (Aroclor 1254) for 24 h under basal and LH-stimulated conditions. After the experimental period, cultured media were collected and used for the assay of testosterone and estradiol. The treated cells were used for the quantification of cell-surface LH receptors and activities of steroidogenic enzymes, such as cytochrome P450 side-chain cleavage enzyme (P450scc), 3β-HSD, and 17β-hydroxysteroid dehydrogenase (17β-HSD). Leydig cellular enzymatic antioxidants, such as superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, γ-glutamyl transpeptidase, glutathione-S-transferase, and nonenzymatic antioxidants, such as vitamins C and E, were assayed. Lipid peroxidation (LPO) and reactive oxygen species (ROS) were also estimated in Leydig cells. In addition, total RNA was isolated from control and Aroclor 1254-exposed Leydig cells to monitor the steady-state mRNA levels by reverse transcription(RT)-PCR for steroidogenic acute-regulatory (StAR) protein, cytochrome P450scc, 3β-HSD, and 17β-HSD. Our results indicated that Aroclor 1254 (10− 9, 10− 8, and 10− 7 M) treatments significantly inhibit basal and LH-stimulated testosterone and estradiol production. In addition, the activities of steroidogenic enzymes, enzymatic and nonenzymatic antioxidants were significantly diminished in a dose-dependent manner. However, LPO and ROS were elevated in a dose-dependent manner under basal and LH-stimulated conditions. RT-PCR analysis of StAR mRNA level showed a decrease only in 10− 7 M dose of Aroclor 1254 treatment, while cytochrome P450scc, 3β-HSD, and 17β-HSD mRNAs were drastically decreased in both 10− 8 and 10− 7 M Aroclor 1254 treatment. These findings suggest that PCBs can act directly on Leydig cells to diminish testosterone production by inhibiting gene expression of steroidogenic enzymes and antioxidant system.

scholarly journals Resveratrol enhances decidualization of human endometrial stromal cells

Reproduction ◽  
2020 ◽  
Vol 159 (4) ◽  
pp. 453-463 ◽  
Author(s):  
Ana Cecilia Mestre Citrinovitz ◽  
Laila Langer ◽  
Thomas Strowitzki ◽  
Ariane Germeyer
Keyword(s):  
Cell Cycle ◽  
Stromal Cells ◽  
Antioxidant Properties ◽  
Trophoblast Invasion ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Cell Cycle Regulators ◽  
Rt Pcr ◽  
Endometrial Stromal Cells

The differentiation of endometrial stromal cells (ESC), named decidualization, is essential to regulate trophoblast invasion and to support pregnancy establishment and progression. Decidualization follows ESC proliferation and it has been described that cell cycle arrest contributes to a proper decidualization. Interestingly, resveratrol, a natural compound derived from grapes with antioxidant properties, has been widely studied in relation to endometrial health. However, little is known about the effect of resveratrol supplementation during decidualization. Therefore, in this study we evaluate the effect of resveratrol supplementation during decidualization. We used primary and immortalized human ESC and we decidualized them in vitro with a decidualization cocktail containing medroxyprogesterone acetate, estradiol and 8-Bromo-cyclic AMP. Pre-decidualized cells were further treated with the decidualization cocktail supplemented with resveratrol. Our results show that resveratrol supplementation increased, in a dose-dependent manner, the expression levels of prolactin and IGFBP1 (RT-PCR and ELISA), indicating an enhanced in vitro decidualization of human ESC. This enhanced decidualization was accompanied by a decrease in cell proliferation (crystal violet and CellTiter proliferation assay) and by changes in the mRNA levels of key cell cycle regulators (RT-PCR). Furthermore, resveratrol supplementation seemed to enhance decidualization by reinforcing the effect of the decidualization cocktail. We believe that resveratrol could to be an effective supplementation to reinforce hormone action during human ESC decidualization and that further insights into resveratrol action and its interaction with estradiol and progesterone signaling pathways could facilitate the identification of new therapeutic strategies for the improvement of women’s health.

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.

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.

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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