Shear stress increases expression of a KATP channel in rat and bovine pulmonary vascular endothelial cells
1 Institute for Environmental Medicine; and 2 Institute for Medicine and Engineering, University of Pennsylvania, Medical Center, Philadelphia, Pennsylvania 19104; and 3 Department of Cellular and Molecular Pharmacology, University of South Alabama, Mobile, Alabama 36688 Submitted 5 November 2002 ;...
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Published in | American Journal of Physiology: Cell Physiology Vol. 285; no. 4; pp. C959 - C967 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
United States
01.10.2003
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Subjects | |
Online Access | Get full text |
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Summary: | 1 Institute for Environmental Medicine; and
2 Institute for Medicine and Engineering, University of
Pennsylvania, Medical Center, Philadelphia, Pennsylvania 19104; and
3 Department of Cellular and Molecular Pharmacology,
University of South Alabama, Mobile, Alabama 36688
Submitted 5 November 2002
; accepted in final form 16 June 2003
We have shown previously that acute ischemia leads to depolarization of
pulmonary microvascular endothelial cells that is prevented with cromakalim,
suggesting the presence of ATP-sensitive K + (K ATP )
channels in these cells. Thus K ATP channel expression and activity
were evaluated in rat pulmonary microvascular endothelial cells (RPMVEC) by
whole cell current measurements, dot blot (mRNA), and immunoblot (protein) for
the inwardly rectifying K + channel (K IR ) 6.2 subunit and
fluorescent ligand binding for the sulfonylurea receptor (SUR). Low-level
expression of a K ATP channel was detected in endothelial cells in
routine (static) culture and led us to examine whether its expression is
inducible when endothelial cells are adapted to flow. Channel expression (mRNA
and both K IR 6.2 and SUR proteins) and inwardly rectified membrane
current by patch clamp increased significantly when RPMVEC were adapted to
flow at 10 dyn/cm 2 for 24 h in either a parallel plate flow chamber
or an artificial capillary system. Induction of the K ATP channel
with flow adaptation was also observed in bovine pulmonary artery endothelial
cells. Flow-adapted but not static RPMVEC showed cellular plasma membrane
depolarization upon stop of flow that was inhibited by a K ATP
channel opener and prevented by addition of cycloheximide to the medium during
the flow adaptation period. These studies indicate the induction of
K ATP channels by flow adaptation in pulmonary endothelium and that
the expression and activity of this channel are essential for the endothelial
cell membrane depolarization response with acute decrease in shear stress.
flow adaptation; K IR 6.2; sulfonylurea receptor; fluorescent glyburide; pulmonary microvascular endothelial cells
Address for reprint requests and other correspondence: A. B. Fisher, Institute
for Environmental Medicine, Univ. of Pennsylvania School of Medicine, 1 John
Morgan Bldg., 3620 Hamilton Walk, Philadelphia, PA 19104-6068 (E-mail:
abf{at}mail.med.upenn.edu ). |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0363-6143 1522-1563 |
DOI: | 10.1152/ajpcell.00511.2002 |