scholarly journals Cyclosporine stimulates the renal epithelial sodium channel by elevating cholesterol

2009 ◽  
Vol 296 (2) ◽  
pp. F284-F290 ◽  
Author(s):  
Jing Wang ◽  
Zhi-Ren Zhang ◽  
Chu-Fang Chou ◽  
You-You Liang ◽  
Yuchun Gu ◽  
...  
Keyword(s):  
Sodium Channel ◽  
Epithelial Sodium Channel ◽  
Disulfonic Acid ◽  
Severe Side Effect ◽  
Open Probability ◽  
A6 Cells ◽  
Induced Hypertension ◽  
Microscopy Data ◽  
Abca1 Protein ◽  
Epithelial Sodium Channel Enac

Cyclosporine A (CsA) is an efficient immunosuppressant used for reducing allograft rejection but with a severe side effect of causing hypertension. We hypothesize that the renal epithelial sodium channel (ENaC) may participate in CsA-induced hypertension. In the present study, we used the patch-clamp cell-attached configuration to examine whether and how CsA stimulates ENaC in A6 distal nephron cells. The data showed that CsA significantly increased ENaC open probability. Since CsA is an inhibitor of the ATP-binding cassette A1 (ABCA1) transporter, we employed 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid (DIDS), another ABCA1 inhibitor, and found that DIDS mimicked the effects of CsA on ENaC basal and cholesterol-induced activity but without any additive effect if combined with CsA. CsA and DIDS also had an identical effect on reduced ENaC activity caused by cholesterol extraction. ABCA1 protein was detected in A6 cells by Western blot analysis. Confocal microscopy data showed that both CsA and DIDS facilitated A6 cells to uptake cholesterol. Since enhanced ENaC activity is known to cause hypertension, these data together suggest that CsA may cause hypertension by stimulating ENaC through a pathway associated with inhibition of ABCA1 and consequent elevation of cholesterol in the cells.

Role of SGK in hormonal regulation of epithelial sodium channel in A6 cells

2003 ◽  
Vol 284 (2) ◽  
pp. C404-C414 ◽  
Author(s):  
Diego Alvarez de la Rosa ◽  
Cecilia M. Canessa
Keyword(s):  
Sodium Channel ◽  
Hormonal Regulation ◽  
Apical Membrane ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Epithelial Sodium Channel ◽  
Hormonal Stimulation ◽  
A6 Cells ◽  
Epithelial Sodium Channel Enac

The purpose of this study was to examine the role of the serum- and glucocorticoid-induced kinase (SGK) in the activation of the epithelial sodium channel (ENaC) by aldosterone, arginine vasopressin (AVP), and insulin. We used a tetracycline-inducible system to control the expression of wild-type (SGK[Formula: see text]), constitutively active (S425D mutation; SGK[Formula: see text]), or inactive (K130M mutation; SGK[Formula: see text]) SGK in A6 cells independently of hormonal stimulation. The effect of SGK expression on ENaC activity was monitored by measuring transepithelial amiloride-sensitive short-circuit current ( I sc) of transfected A6 cell lines. Expression of SGK[Formula: see text] or SGK[Formula: see text] and aldosterone stimulation have additive effects on I sc. Although SGK could play some role in the aldosterone response, our results suggest that other mechanisms take place. SGK[Formula: see text] abrogates the responses to AVP and insulin; hence, in the signaling pathways of these hormones there is a shared step that is stimulated by SGK. Because AVP and insulin induce fusion of vesicles to the apical membrane, our results support the notion that SGK promotes incorporation of channels in the apical membrane.

scholarly journals Hydrogen Sulfide Prevents Advanced Glycation End-Products Induced Activation of the Epithelial Sodium Channel

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Qiushi Wang ◽  
Binlin Song ◽  
Shuai Jiang ◽  
Chen Liang ◽  
Xiao Chen ◽  
...  
Keyword(s):  
Sodium Channel ◽  
Advanced Glycation End Products ◽  
Epithelial Sodium Channel ◽  
Sodium Reabsorption ◽  
Metabolic Memory ◽  
Advanced Glycation ◽  
Open Probability ◽  
A6 Cells ◽  
Glycation End Products ◽  
End Products

Advanced glycation end-products (AGEs) are complex and heterogeneous compounds implicated in diabetes. Sodium reabsorption through the epithelial sodium channel (ENaC) at the distal nephron plays an important role in diabetic hypertension. Here, we report that H2S antagonizes AGEs-induced ENaC activation in A6 cells. ENaC open probability(PO)in A6 cells was significantly increased by exogenous AGEs and that this AGEs-induced ENaC activity was abolished by NaHS (a donor of H2S) and TEMPOL. Incubating A6 cells with the catalase inhibitor 3-aminotriazole (3-AT) mimicked the effects of AGEs on ENaC activity, but did not induce any additive effect. We found that the expression levels of catalase were significantly reduced by AGEs and both AGEs and 3-AT facilitated ROS uptake in A6 cells, which were significantly inhibited by NaHS. The specific PTEN and PI3K inhibitors, BPV(pic) and LY294002, influence ENaC activity in AGEs-pretreated A6 cells. Moreover, after removal of AGEs from AGEs-pretreated A6 cells for 72 hours, ENaCPOremained at a high level, suggesting that an AGEs-related “metabolic memory” may be involved in sodium homeostasis. Our data, for the first time, show that H2S prevents AGEs-induced ENaC activation by targeting the ROS/PI3K/PTEN pathway.

scholarly journals Ankyrin G Expression Regulates Apical Delivery of the Epithelial Sodium Channel (ENaC)

2016 ◽  
Vol 292 (1) ◽  
pp. 375-385 ◽  
Author(s):  
Christine A. Klemens ◽  
Robert S. Edinger ◽  
Lindsay Kightlinger ◽  
Xiaoning Liu ◽  
Michael B. Butterworth
Keyword(s):  
Sodium Channel ◽  
Epithelial Sodium Channel ◽  
Ankyrin G ◽  
Epithelial Sodium Channel Enac

The epithelial sodium channel (ENaC) is intracellularly located as a tetramer

2002 ◽  
Vol 444 (4) ◽  
pp. 549-555 ◽  
Author(s):  
Lisette Dijkink ◽  
Anita Hartog ◽  
René Bindels ◽  
Carel van Os
Keyword(s):  
Sodium Channel ◽  
Epithelial Sodium Channel ◽  
Epithelial Sodium Channel Enac

Differential Regulation of the Epithelial Sodium Channel (ENaC) in Rat Kidney, Lung and Distal Colon in Response to Aldosterone.

Hypertension ◽  
2000 ◽  
Vol 36 (suppl_1) ◽  
pp. 724-724
Author(s):  
Shyama M E Masilamani ◽  
Gheun-Ho Kim ◽  
Mark A Knepper
Keyword(s):  
Sodium Channel ◽  
Epithelial Sodium Channel ◽  
Distal Colon ◽  
Β Subunit ◽  
Dietary Salt ◽  
Α Subunit ◽  
Salt Restriction ◽  
Γ Subunit ◽  
Dietary Salt Restriction ◽  
Epithelial Sodium Channel Enac

P170 The mineralocorticoid hormone, aldosterone increases renal tubule Na absorption via increases in the protein abundances of the α-subunit of the epithelial sodium channel (ENaC) and the 70 kDa form of the γ- subunit of ENaC (JCI 104:R19-R23). This study assesses the affect of dietary salt restriction on the regulation of the epithelial sodium channel (ENaC) in the lung and distal colon, in addition to kidney, using semiquantitative immunoblotting. Rats were placed initially on either a control Na intake (0.02 meq/day), or a low Na intake (0.2 meq/day) for 10 days. The low salt treated rats demonstrated an increase in plasma aldosterone levels at day 10 (control = 0.78 + 0.32 nM; Na restricted = 3.50 + 1.30 nM). In kidney homogenates, there were marked increases in the band density of the α-subunit of ENaC (286 % of control) and the 70 kDa form of γ-subunit of ENaC (262 % of control), but no increase in the abundance of the β-subunit of ENaC. In lung homogenates, there was no significant change in the band densities of the α, β, or γ subunits of ENaC. In distal colon, there was an increase in the band density of the β-subunit of ENaC (311 % of control) and an increase in both the 85 kDa (2355% of control) and 70 kDa (843 % of control) form of the γ subunit of ENaC in response to dietary Na restriction. However, there was no significant difference in the band density of the α-subunit of ENaC. These findings demonstrate tissue specific regulation of the three subunits of ENaC in response to dietary salt restriction.

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