title: Na(+) /H(+) exchanger 1 (NHE1) function is necessary for maintaining mammary tissue architecture.
abstract: BACKGROUND
  The mammary gland is an ideal model to study the link between form and function in normal tissue. Perhaps as interesting as the cues necessary to generate this structure are the signals required to maintain its branched architecture over the lifetime of the organism, since likely these pathways are de-regulated in malignancies. Previously, we have shown that the Na(+) /H(+) exchanger 1 (NHE1), a critical regulator of intracellular pH, was necessary for mammary branching morphogenesis. Here we provide strong evidence that NHE1 function is also necessary for maintaining mammary branched architecture.
  
  
  RESULTS
  Inhibition of NHE1 with 5-N-Methy-N-isobutyl amiloride (MIA) on branched structures resulted in a rapid (within 24 hr) and reversible loss of branched architecture that was not accompanied by any overt changes in cell proliferation or cell death. NHE1 inhibition led to a significant acidification of intracellular pH in the branched end buds that preceded a number of events, including altered tissue polarity of myoepithelial cells, loss of NHE1 basal polarity, F-actin rearrangements, and decreased E-cadherin expression.
  
  
  CONCLUSIONS
  Our results implicate NHE1 function and intracellular pH homeostasis as key factors that maintain mammary tissue architecture, thus, indirectly allowing for mammary function as a milk-providing (form) and -producing (function) gland.
authors.affiliation: Department of Biology, College of Staten Island, Staten Island, New York; Biology Doctoral Program, City University of New York Graduate Center, New York, New York.
authors.forename: Edmund C
authors.initials: EC
authors.lastname: Jenkins
authors.forename: Shawon
authors.initials: S
authors.lastname: Debnath
authors.forename: Sophia
authors.initials: S
authors.lastname: Varriano
authors.forename: Stephen
authors.initials: S
authors.lastname: Gundry
authors.forename: Jimmie E
authors.initials: JE
authors.lastname: Fata
mesh_terms: D000199:Actins / Q000378:metabolism; D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D015820:Cadherins / Q000378:metabolism; D027682:Cation Transport Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016923:Cell Death / Q000502:physiology; D016764:Cell Polarity / Q000502:physiology*; D002478:Cells, Cultured; D005260:Female; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D015151:Immunoblotting; D007633:Keratins / Q000378:metabolism; D008321:Mammary Glands, Animal / Q000033:anatomy & histology* / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D010590:Phalloidine; D000074082:Sodium-Hydrogen Exchanger 1; D017923:Sodium-Hydrogen Exchangers / Q000037:antagonists & inhibitors / Q000378:metabolism*; D062826:Zonula Occludens-1 Protein / Q000378:metabolism
chemical_list: D000199:Actins; D015820:Cadherins; D027682:Cation Transport Proteins; C490997:Slc9a1 protein, mouse; D000074082:Sodium-Hydrogen Exchanger 1; D017923:Sodium-Hydrogen Exchangers; C569043:Tjp1 protein, mouse; D062826:Zonula Occludens-1 Protein; D010590:Phalloidine; D007633:Keratins; D000584:Amiloride; C056369:5-(N-methyl-N-isobutyl)amiloride
keywords: NHE1; cellular polarity; intracellular pH; mammary epithelial ducts; mammary tissue architecture; sodium hydrogen exchanger; tissue polarity