Document Detail

Effects of NHE1 expression level on CHO cell responses to environmental stress.
MedLine Citation:
PMID:  15801799     Owner:  NLM     Status:  MEDLINE    
Ammonia, lactate and CO(2) inhibit animal cell growth. Accumulation of these metabolic byproducts also causes a decrease in intracellular pH (pH(i)). Transport systems regulate pH(i) in eukaryotic cells. Ion transporters have been cloned and overexpressed in cells but have not been examined for protection against the buildup of ammonia, lactate or CO(2). The Na(+)/H(+) exchangers (NHE) transport H(+) ions from cells during acidification to increase pH(i). We examined whether overexpression of NHE1 would provide CHO cells with greater protection from elevated ammonia, lactate or CO(2). NHE1 CHO cells were compared to MT2-1-8 ("normal" levels of NHE) and AP-1 (devoid of any NHE activity) CHO cell lines. Expression of at least "normal" levels of NHE1 is necessary for CHO cell survival during exposure to 30 mM lactic acid without pH adjustment or to 20 mM NH(4)Cl with pH adjustment. Resistance to an acute acid-load increased when NHE1 was overexpressed in CHO cells. Surprisingly, the inhibitory effect on cell growth at 195 mmHg pCO(2)/435 mOsm/kg (normal levels are 40 mmHg pCO(2)/ 320 mOsm/kg) was not affected by the NHE1 level. Also, there was no further decrease in CHO cell growth in the absence of NHE1 expression during elevated osmolality alone (up to 575 mOsm/kg).
Lisa R Abston; William M Miller
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Biotechnology progress     Volume:  21     ISSN:  8756-7938     ISO Abbreviation:  Biotechnol. Prog.     Publication Date:    2005 Mar-Apr
Date Detail:
Created Date:  2005-04-01     Completed Date:  2005-07-06     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  8506292     Medline TA:  Biotechnol Prog     Country:  United States    
Other Details:
Languages:  eng     Pagination:  562-7     Citation Subset:  IM    
Interdepartmental Biological Sciences Program, Northwestern University, Evanston, Illinois 60208, USA.
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MeSH Terms
Ammonia / pharmacology*
CHO Cells
Carbon Dioxide / pharmacology*
Cell Division
Hydrogen-Ion Concentration
Lactic Acid / pharmacology*
Osmolar Concentration
Oxidative Stress
Sodium-Hydrogen Antiporter / metabolism*
Grant Support
Reg. No./Substance:
0/Sodium-Hydrogen Antiporter; 124-38-9/Carbon Dioxide; 50-21-5/Lactic Acid; 7664-41-7/Ammonia

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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