scholarly journals P273 BI 443651 and BI 1265162 demonstrate in vitro inhibition of epithelial sodium channel (ENaC) in the Ussing chamber

2019 ◽  
Vol 18 ◽  
pp. S134
Author(s):  
B. Jung ◽  
P. Iacono ◽  
K. Benediktus ◽  
M. Hahn ◽  
G. Göggerle ◽  
...  
2021 ◽  
Vol 8 (1) ◽  
pp. e000861
Author(s):  
Sangya Yadav ◽  
Ciaran A Shaughnessy ◽  
Pamela L Zeitlin ◽  
Preston E Bratcher

IntroductionThe incubation of airway epithelia cells at low temperatures is a common in vitro experimental approach used in the field of cystic fibrosis (CF) research to thermo-stabilise F508del-CFTR and increase its functional expression. Given that the airway epithelium includes numerous ion transporters other than CFTR, we hypothesised that there was an impact of low temperature incubation on CFTR-independent ionoregulatory mechanisms in airway epithelia derived from individuals with and without CF.MethodsAfter differentiation at the air–liquid interface, nasal epithelia were incubated at either 37°C or 29°C (low temperature) for 48 hours prior to analysis in an Ussing chamber.ResultsWhile F508del-CFTR activity was increased after low temperature incubation, activity of CFTR in non-CF epithelia was unchanged. Importantly, cultures incubated at 29°C demonstrated decreased transepithelial potential difference (TEPD) and short-circuit currents (Isc) at baseline. The predominant factor contributing to the reduced baseline TEPD and Isc in 29°C cultures was the reduced activity of the epithelial sodium channel (ENaC), evidenced by a reduced responsiveness to amiloride. This effect was observed in cells derived from both non-CF and CF donors.DiscussionSignificant transcriptional downregulation of ENaC subunits β and γ were observed, which may partially explain the decreased ENaC activity. We speculate that low temperature incubation may be a useful experimental paradigm to reduce ENaC activity in in vitro epithelial cultures.


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

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

Hypertension ◽  
2000 ◽  
Vol 36 (suppl_1) ◽  
pp. 724-724
Author(s):  
Shyama M E Masilamani ◽  
Gheun-Ho Kim ◽  
Mark A Knepper

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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