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Activity and protein expression of Na+/K+ ATPase are reduced in microvillous syncytiotrophoblast plasma membranes isolated from pregnancies complicated by intrauterine growth restriction

Johansson, Martin LU ; Karlsson, L.; Wennergren, M.; Jansson, T. and Powell, Theresa L. (2003) In Journal of Clinical Endocrinology and Metabolism 88(6). p.2831-2837
Abstract

In contrast to classical transporting epithelia, the Na+/K+ ATPase is distributed to both the microvillous membrane (MVM) and the basal membrane (BM) of the placental syncytiotrophoblast. Na+/K+ ATPase is important in maintaining the electrochemical gradient for Na+, which represents the driving force for Na+-coupled transport of nutrients. We hypothesized that syncytiotrophoblast Na+/K+-ATPase activity is reduced in intrauterine growth restriction (IUGR). We isolated MVM and BM from control (n = 10) and IUGR placentas (n = 11). The protein expression of Na+/K+-ATPase α1-subunit was determined by Western blotting and... (More)

In contrast to classical transporting epithelia, the Na+/K+ ATPase is distributed to both the microvillous membrane (MVM) and the basal membrane (BM) of the placental syncytiotrophoblast. Na+/K+ ATPase is important in maintaining the electrochemical gradient for Na+, which represents the driving force for Na+-coupled transport of nutrients. We hypothesized that syncytiotrophoblast Na+/K+-ATPase activity is reduced in intrauterine growth restriction (IUGR). We isolated MVM and BM from control (n = 10) and IUGR placentas (n = 11). The protein expression of Na+/K+-ATPase α1-subunit was determined by Western blotting and found to be slightly reduced in MVM isolated from IUGR (-10%; P < 0.05) placentas. Na+/K+ ATPase activity was measured as the ouabain-sensitive, K+-dependent cleavage of the fluorescent pseudosubstrate 3-O-methylfluorescein phosphate and was reduced by 35% in MVM obtained from IUGR placentas (P < 0.02). To assess the transcriptional levels of Na+/K+-ATPase mRNA, real time PCR was used. No significant changes in steady state mRNA levels for Na+/K+-ATPase were detected. The expression of the Na+/K+-ATPase α1-subunit and Na+/K+-ATPase activity in the BM were unaffected in cases of IUGR. These data suggest that Na+/K+-ATPase activity is reduced in the MVM of placentas from IUGR pregnancies. These changes might impair the function of Na+-coupled transporters and contribute to the reduced growth of these fetuses.

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author
publishing date
type
Contribution to journal
publication status
published
in
Journal of Clinical Endocrinology and Metabolism
volume
88
issue
6
pages
2831 - 2837
publisher
The Endocrine Society
external identifiers
  • scopus:0038239459
ISSN
0021-972X
DOI
10.1210/jc.2002-021926
language
English
LU publication?
no
id
39c67f2f-8261-4e79-9be9-f030643e2b96
date added to LUP
2017-04-10 16:16:13
date last changed
2017-07-30 05:23:54
@article{39c67f2f-8261-4e79-9be9-f030643e2b96,
  abstract     = {<p>In contrast to classical transporting epithelia, the Na<sup>+</sup>/K<sup>+</sup> ATPase is distributed to both the microvillous membrane (MVM) and the basal membrane (BM) of the placental syncytiotrophoblast. Na<sup>+</sup>/K<sup>+</sup> ATPase is important in maintaining the electrochemical gradient for Na<sup>+</sup>, which represents the driving force for Na<sup>+</sup>-coupled transport of nutrients. We hypothesized that syncytiotrophoblast Na<sup>+</sup>/K<sup>+</sup>-ATPase activity is reduced in intrauterine growth restriction (IUGR). We isolated MVM and BM from control (n = 10) and IUGR placentas (n = 11). The protein expression of Na<sup>+</sup>/K<sup>+</sup>-ATPase α<sub>1</sub>-subunit was determined by Western blotting and found to be slightly reduced in MVM isolated from IUGR (-10%; P &lt; 0.05) placentas. Na<sup>+</sup>/K<sup>+</sup> ATPase activity was measured as the ouabain-sensitive, K<sup>+</sup>-dependent cleavage of the fluorescent pseudosubstrate 3-O-methylfluorescein phosphate and was reduced by 35% in MVM obtained from IUGR placentas (P &lt; 0.02). To assess the transcriptional levels of Na<sup>+</sup>/K<sup>+</sup>-ATPase mRNA, real time PCR was used. No significant changes in steady state mRNA levels for Na<sup>+</sup>/K<sup>+</sup>-ATPase were detected. The expression of the Na<sup>+</sup>/K<sup>+</sup>-ATPase α<sub>1</sub>-subunit and Na<sup>+</sup>/K<sup>+</sup>-ATPase activity in the BM were unaffected in cases of IUGR. These data suggest that Na<sup>+</sup>/K<sup>+</sup>-ATPase activity is reduced in the MVM of placentas from IUGR pregnancies. These changes might impair the function of Na<sup>+</sup>-coupled transporters and contribute to the reduced growth of these fetuses.</p>},
  author       = {Johansson, Martin and Karlsson, L. and Wennergren, M. and Jansson, T. and Powell, Theresa L.},
  issn         = {0021-972X},
  language     = {eng},
  month        = {06},
  number       = {6},
  pages        = {2831--2837},
  publisher    = {The Endocrine Society},
  series       = {Journal of Clinical Endocrinology and Metabolism},
  title        = {Activity and protein expression of Na+/K+ ATPase are reduced in microvillous syncytiotrophoblast plasma membranes isolated from pregnancies complicated by intrauterine growth restriction},
  url          = {http://dx.doi.org/10.1210/jc.2002-021926},
  volume       = {88},
  year         = {2003},
}